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Misc Combined Correspondence 2015-2023December 31, 2015 Todd Whipple Whipple Consulting Engineers, Inc. 2528 N. Sullivan Rd. Spokane Valley, WA 99216 Paul Nelson IPEC P.O. Box 1566 Spokane Valley, WA 99037 Re: PAINTED HILLS FLOODPLAIN REVIEW City Project No.: SUB-2015-0001 Development Engineering 11707 E Sprague Ave Suite 106 • Spokane Valley WA 99206 509.921.1000 • Fax: 509.921.1008 • cityhall@spokanevalley.org Ken Puhn West Consultants 2601 25th Street SE, Suite 450 Salem, OR 97302 GENERAL Review Comments for Submittal #1 We have looked over the submittal of the documents provided for the above-mentioned project. The goal of our review is, within our capacity, to make sure that the submittal to FEMA is complete and provides information enabling FEMA to review and see if the modifications "have been adequately designed" and "will be adequately maintained" (MT-2 submittal instructions). Do to the complexity of this project, we felt that it would be more expeditious to send out a set of comments consisting of some of the major items (this document) but then have a meeting where more detailed comments and concerns can be discussed in person. In this review, there were a few items for which we request further clarification noted below. Note: SS = Spokane Valley Street Standards, SRSM = Spokane Regional Stormwater Manual, ROW = right of way, General 1. These comments and those to be provided at the subsequent detailed-comment review meeting are to be applied in conjunction with comments from Spokane County. If any conflict should occur between the review comments from the two jurisdictions, please bring it to our attention for resolution. 2. Please apply for a Floodplain Development permit and a Land Disturbance permit for both Spokane Valley and Spokane County. Dev. Eng.: SUB-2015-0001 PAINTED HILLS Floodplain Review-General.docx 3. Contact Ecology regarding the need for a NPDES Construction Stormwater Permit. 4. If there is any concern with the acceptance of the design by FEMA, we recommend first having a preliminary discussion with Lynn Schmidt/Ecology prior to submittal to FEMA. FEMA Forms and Submittal 5. MT-2 Form Instructions a. Form 2 & 3 -check that they are completely filled out. b. Hydraulic calculations -include digital files for calcs supporting the Flood Control improvement design Civil Plans 6. Prior to Civil Plans approval the following must be accomplished: a. Include easement recording numbers on plans b. Provide a single, complete Financial Plan and an Operations and Maintenance (O&M) Manual for the project components, including the stormwater systems, levees, impact mitigations, etc. See SRSM chapter 11 for details. Include the person/entity responsible for the financing, operation and maintenance so that the project will be in compliance with SRSM chapter 11; 44 CFR §60.3(b)(7), §65.6(a)(12), and §65.lO(d). 7. General a. The drainage plans shall provide enough detail for a third party to construct the proposed facilities per the engineer's design (SRSM 3.5.2) b. Confirm that the plans contain the applicable minimum plan elements per SS and SRSM c. Make sure the design details are coordinated between the pre-app comments, Flood Control plans, the HEC-RAS models, the Geotechnical recommendations and the Biological Evaluation d. Stormwater facilities (including the park area) and maintenance access roads outside right- of-way and border easements must be in a tract or easement (SRSM 11.1.6, 11.2). 8. For the final submittal, the cover sheet shall be signed and dated by project proponent or agent 9. Sheet FC4.0 South Grading and Drainage Plan a. A note in the HEC-RAS PCM model says that Thorpe is raised at the culverts. If this is true provide design including elements per SS 4.6, especially SS 4.6.3. 10. Sheet FC4.1 West Grading and Drainage Plan a. Show proposed accesses from the site to Dishman-Mica Road that cross the levee. How will these accesses be constructed so as to not compromise the levee's function? Flood Control Development Narrative (dated July 23, 2015) 11. Report Narrative a. Page 3- i. Infiltration Rate -the gravel galleries are closer to P-5 (TP28) and the soils are more similar (SM) than those at P-3. Use infiltration rate from P-5 for the gravel galleries. ii. Hydraulic Analysis-Hydraflow is not on FEMA's list of approved software programs. We recommend that before submitting the study you check with FEMA to see if they will accept this software. Page 2 Dev. Eng.: SUB-2015-0001 PAINTED HILLS Floodplain Review -General.docx b. Page 6, Secondary Flow Across Madison Road -at STA 20+44 and 24+41 the drywell outflow rates provided in the table appear to be derived from TP-19 where the soils are SP but the test pits closest to these drywells, TP-20, TP-24 and TP-25, show the soils to be either clay or clayey sand. Please use drywell outflow rates that would be expected from these latter soils. 12. West half of the gravel gallery system is represented by Geotechnical Evaluation Phase II (IPEC 2015) boring 8-9. This boring shows that groundwater is very shallow, 11 feet below the ground surface, which puts the groundwater level near the top of the perforated drywell barrel sections and gravel galleries. We are concerned that if the groundwater is this high during a drought year then during a year that is wet enough to produce a 100-year storm the groundwater level will be significantly higher, high enough to make the drywell and gravel gallery infiltration ineffective. This concern is also applicable to the east portion of the infiltration system. Please address. Preliminary Geotechnical Evaluation, Phase 2 13. Include this report in the FEMA submittal Geotechnical Evaluation, Proposed Levee (Levee along east side of Dishman-Mica road) 14. Section 3.4 Closures -note that the proposed access appears to penetrate the levee If you have any questions, please email me at hallen@spokanevalley.org or call me at (509) 720-5319. Sincerely, enry M. Allen Development Engineer Copies: • Marianne Barrentine, Spokane County Public Works Building, 1026 W. Broadway Ave., Spokane, WA 99260 • Spokane Valley Planning Department -Deanna Horton • Spokane Valley Development Engineering-Project File Page 3 January 6, 2016 Todd Whipple Whipple Consulting Engineers, Inc. 2528 N. Sullivan Rd. Spokane Valley, WA 99216 Paul Nelson IPEC P.O. Box 1566 Spokane Valley, WA 99037 Development Engineering 11707 E Sprague Ave Suite 106 • Spokane Valley WA 99206 509.921.1000. Fax: 509.921.1008. cityhall®spokanevalley.org Ken Puhn West Consultants 2601 25th Street SE, Suite 450 Salem, OR 97302 Re: PAINTED HILLS FLOODPLAIN REVIEW -Comment Review Meeting Document City Project No.: SUB-201S-0001 DETAILED Review Comments for Submittal #1 We have looked over the submittal of the documents provided for the above-mentioned project. The goal of our review is, within our capacity, to make sure that the submittal to FEMA is complete and provides information enabling FEMA to review and see if the modifications ilhave been adequately designed" and ilwill be adequately maintained" (MT-2 submittal instructions). liThe supporting data must include all the information FEMA needs to review and evaluate the request" (44 CFR 65.6(a}{1)). In this review, there were a few items for which we request further clarification, provided below. Note: SS = Spokane Valley Street Standards, SRSM = Spokane Regional Stormwater Manual, ROW = right of way, General 1. These comments are to be applied in conjunction with comments from Spokane County. If any conflict should occur between the two reviews please bring it to our attention for resolution. 2. Please apply for a Floodplain Development permit and a Land Disturbance permit for both Spokane Valley and Spokane County. Include permit numbers on the plans. 3. Contact Ecology regarding the need for a NPDES Construction Stormwater Permit. 4. If there is any concern with the acceptance of the design by FEMA, we recommend first having a preliminary discussion with Lynn Schmidt/Ecology prior to submittal to FEMA. 5. Prior to construction permit release, the following needs to be accomplished: Dev. Eng.: SUB-2015-0001 PAINTED HILLS Floodplain Reviewl -Detailed.docx a. Copy of CLOMR from FEMA b. Plan approval from Spokane Valley and Spokane County 6. Prior to construction acceptance, the following needs to be accomplished: a. Copies ofthe Department of Ecology (DOE) drywell registrations for all new drywells (submitted with construction certification) b. Record drawings showing as-built condition c. Revisions to HEC-RAS model and reassessment of the freeboard if construction has altered the channels from that depicted in the model d. Formation of HOA with CC&R's if it will be responsible for the project components e. Letter from design engineers certifying project constructed according to approved plans and specifications f. Levee certifications (44 CFR 65.10 (e)) g. Construction Certification Package FEMA Forms and Submittal 7. MT-2 Form Instructions a. Form 2, i. D. Common Reg. Requirements -include proof of property owner notifications and evidence of regulatory floodway revision notification b. Form 3, i. C. Bridge/Culvert, 3. -finish filling out this section ii. E. Levee/Floodwall -please use Geotech reports and revised plans to fill out this section. If additional information is needed please bring it to our attention. c. Hydraulic cales -include digital files for cales supporting the Flood Control improvement design Civil Plans 8. Prior to Civil Plans approval the following must be accomplished: a. Recording numbers of the easements for the stormwater facilities (including the park area) and maintenance access roads outside right-of-way and border easements on the plans b. Provide a single, complete Financial Plan and an Operations and Maintenance (O&M) Manual for the funding, operation, maintenance, repair, and replacement of the project components, including the stormwater systems, levees, impact mitigations, etc. as described on the Civil plans and in the reports (such as the Geotech reports and the Biological Evaluation by BSW). Include specific tasks, frequencies and costs. See SRSM chapter 11 for details. Include the person/entity responsible for the financing, operation and maintenance so that the project will be in compliance with SRSM chapter 11; 44 CFR §60.3(b )(7), §65.6(a)(12), and §65.10(d). For the levees, provide a brief description of what some of the repairs may involve. All discussions need to be in terms a non- Page 2 Dev. Eng.: SU8-201S-0001 PAINTED HILLS Floodplain Reviewl -Detailed.docx technical person can understand. If a Financial Plan and an O&M Manual is created for the onsite development then these two manuals need to be under a single cover prior to final acceptance of the onsite construction. c. O&M manual-44 CFR 65.10 (d) states for levees "At a minimum, maintenance plans shall specify the maintenance activities to be performed, the frequency of their performance, and the person by name or title responsible for their performance. " Please make sure these items are covered including the frequency and name of responsible party. Prior to construction acceptance the O&M items mentioned in SRSM chapter 11 (e.g. financial plan, etc.) need to also be included. 9. General a. The drainage plans shall provide enough detail for a third party to construct the proposed facilities per the engineer's design (SRSM3.5.2) b. Confirm that the plans contain the applicable minimum plan elements per SRSM 3.5.2 c. Identify/specify and locate all structures (pipes, manholes, drywells, grates, ponds, levees, berms, fences, access roads, etc.), including their alignments, in space and their boundaries (as applicable). Provide lengths and dimensions as needed. For all structures reference applicable standard plans; make sure references are for correct jurisdiction. d. Provide maintenance access to all stormwater and levee facilities (SRSM 11.1.6), provide approaches where accesses connect to a road e. Stormwater facilities (including the park area) and maintenance access roads outside right-of-way and border easements must be in a tract or easement (SRSM 11.1.6, 11.2). Show easements/tracts on the plans. Easements must be recorded at the County with a copy of what was recorded (with the recording number on it) returned to Development Engineering or Spokane County, as applicable. Recording numbers must be placed on these flood mitigation plans, the on site civil plans (as applicable) and plat (as applicable) prior to final approvals. For drainage easements receiving water from Spokane Valley public facilities, please use the City's form. f. At points along all project levees call out proposed top of levee elevation, BFE and max required freeboard (44 CFR 65.10 (b)(1)(i) ). For levees that will also be used for access provide surfacing details. g. Please include our plans acceptance stamp on each sheet. Plans to be reviewed for acceptance once FEMA comments addressed. h. Include details for the proposed improvements to the existing levee between Thorpe and Dishman-Mica roads. Include, at least, existing and proposed elevations and slopes, elevations of the pedestrian bridges at the levee, cross- section showing existing and proposed geometry with surfacing, other items as mentioned above, items called out in sections 4.8.2, 5.2, 5.5, 6.6 of the Biological Evaluation by BSW and in section 3.4 of the Geotech report for this levee, etc. Evaluate the need for erosion protection at outlet of Thorpe culvert where the model shows velocities around 7 ft/s. Show how the ground will transition from the existing pedestrian bridge elevation to the raised levee elevation. Page 3 Dev. Eng.: SUB-2015-0001 PAINTED HILLS Floodplain Reviewl -Detaifed.docx i. Provide design details mentioned in the Biological Evaluation by BSW showing elk travel corridor improvements (sections 4.7,5.6,5.10,6.1-6.7) and impact mitigations (sections 5.0, 5.2, 5.6, 5.8, 5.10,6.1-6.7) that are pertinent to the improvements shown on these Civil plans. j. Show riparian buffer limits 10. For the final submittal, the cover sheet shall be signed and dated by project proponent or agent 11. Sheet FCO.O Cover sheet, include (SS 4.4.2) - a. Provide the following information: i. Spokane Valley 1. SUB-2015-0001 2. FPD-2015-???? (Floodplain Development permit number) 3. EGR-????-???? (Land Disturbance permit number) ii. Spokane County 1. Floodplain Development permit number 2. Grading permit number b. Include the following drywell construction note on the cover sheet: Construction of every drywell, including fabric and drainrock, shall be observed by the on-site inspector to confirm that it meets the design details and specifications. Drywells not observed shall have their performance verified by a full-scale drywell test. c. Easement recording numbers 12. Sheet FCO.l General Notes a. General Grading Note 6 -add that these elevations shall also be used for finished grade 13. Sheet FC4.0 South Grading and Drainage Plan a. Show existing culverts and alignment of Detail 1 FC4.3 b. For the ponds, per SRSM, detail the maintenance access roads (11.1.6) and fencing (7 .8. 7). For the south pond show how water will get past the fencing and into the pond. c. Show pavement cuts with dimensions d. Show how the north edge of the park area will transition back to existing ground and call out slopes e. A note in the HEC-RAS PCM model says that Thorpe is raised at the culverts. If this is true provide design including elements per SS 4.6, especially SS 4.6.3. f. Identify the dashed lines in Thorpe and Madison Roads g. Through the hydrograph, are the maximum velocities for flows down the slopes into the south pond and the distribution pond high enough to warrant erosion control measures on the slopes? h. Construction notes - i. Recommend calling out all pertinent detail sheets for the facilities ii. Note 4 -compaction -reference the specific Geotech report iii. Note 5 -include that pipe is to be rubber gasketed iv. Note 9 -compaction -reference the specific Geotech report i. Why does the gravel gallery extend all the way to Madison Road? Page 4 Dev. Eng.: SU8-201S-0001 PAINTED HILLS Floodplain Reviewl -Detailed.docx j. Legend -show property lines, proposed concrete and limits of proposed storm water ponds k. Title block -check road name 14. Sheet FC4.1 West Grading and Drainage Plan a. Show proposed accesses from the site to Dishman-Mica Road that cross the levee. How will these accesses be constructed so as to not compromise the levee's function? b. Dishman-Mica Road Section - i. Check road cross-slopes ii. Call out centerline iii. Future development should include a 6 foot sidewalk iv. Levee top should be shown higher than the road, provide range of distances between edge of future development and top of levee v. Provide path surfacing details 15. Sheet FC4.2 Triangle Pond a. Plan view- i. provide lines to show alignment of levee and adjacent channel ii. Show existing crossings to be removed as mentioned in the Geotech levee report section 3.1 iii. Show culvert at start of channel b. Construction Note 2 -provide pond access road details. c. For the pond and levee, per SRSM, detail the maintenance access road (11.1.6) and fencing (7.8.7) d. Levee Detail- i. Note -compaction -reference the specific Geotech report ii. show location of alignment line iii. specify width of slope between levee and channel and/or depth of channel iv. specify some details for slope at right bank of channel e. Title block -provide correct location 16. Sheet FC4.3 Grading and Drainage Details a. Provide design cales and details for the drywell rock b. Forebay Ponds Section i. Sidewalk is 5' ii. Confirm that drywell rock at culvert outlet will not erode iii. Show and callout drywell in the overflow/park area to identify rim elevation iv. Show right-of-way and border easement c. Gravel Gallery- i. provide pipe details. Is pipe perforated? ii. Specify geotextile d. Title block -provide correct location 17. Sheet FC5.0 Madison Drainage Plan a. Show road alignment with stationing, confirm future road widening width. b. Construction Notes- Page 5 Dev. Eng.: SU8-201S-0001 PAINTED HILLS Floodplain Reviewl -Detailed.docx i. Note 1-have arrows point to portion of pipe to be removed ii. Note 2 -include that minimum pavement section is 4/6 III. Note 5 -confirm pipe type on WSDOT pipe cover tables c. Title block -provide correct location 18. Sheet FC5.1 Pond Details a. Confirm that - i. The maintenance access roads {including alignment, cross-section, width, surfacing, slope, etc.} and fencing are detailed. Maintenance road must go within 15 feet of structures. ii. All side slopes are called out b. Forebay -show and dimension the drywell rock c. Collection pond -provide erosion protection on side slopes as needed d. Triangle Pond -confirm that maintenance road provides access to all structures e. Construction Notes- i. Note 3 -what is a CMD pipe? ii. Notes 6 & 7 -provide cross-sections and rock details. Need geotextile? f. Title block -provide correct location 19. Sheet FC9.0 -FC9.3 -Erosion Control a. General notes - i. include reference to Spokane Valley ii. Please add a note to the ESC standard notes that "A site log shall be completed with the project per SS 5.4" b. Show silt fence and stockpile locations c. Check numbering on Appendix 9A notes d. Title blocks -provide correct location Flood Control Development Narrative (dated July 23, 2015) 20. SRSM 3.4 -provide a. short discussion about floodplain background {e.g. see Biological Evaluation by BSW, sections 4.8.1, 4.8.2}, Painted Hills and how this project fits in, b. include discussion of Geotech Phase II study, c. maps showing locations of- i. all components discussed in report ii. all Geotech evaluation sites {Phase I and II} with the proposed flood mitigation components iii. contributing drainage basins iv. off-site easements d. calculations for all applicable structures such as -maximum velocities for flows down slopes into the south pond and the distribution pond, maximum velocities out of the 36-inch culverts, riprap sizing at culvert outlets, capacity ratings for beehive grates and gravel gallery pipe entrances, design calcs for v-ditch into triangle pond and riprap pad, etc. 21. Report Narrative Page 6 Dev. Eng.: SU8-201S-0001 PAINTED HILLS Floodplain Reviewl -Detailed.docx a. Page 1, Concept Design and Process -since the stormwater is being directly injected into the ground, how will this water be treated? b. Page 2- i. Both Ponds in Tandem - 1. Confirm that pipe inverts are 1.55 feet above pond bottom 2. How will the separation in elevation remove anything other than large suspended solids? Is the residence time long enough to enable fine sands and smaller particles to settle out? (note the forebay discussion mentions silt deposits) 3. Silt is mentioned as accumulating in the forebay. O&M manual needs to discuss maintenance details to ensure that the silt is removed ii. Broad Crested Weir- c. Page 3- 1. What is the 2.22 foot depth measured from? 2. Provide information supporting that the floating filter will have 10 times the surface area i. Infiltration Rate -the gravel galleries are closer to P-5 (TP28) and the soils are more similar at P-5 (SM) than those at P-3. Use infiltration rate from P-5 for the gravel galleries. ii. Hydraulic Analysis - 1. Hydraflow is not on FEMA's list of approved software programs. We recommend that before submitting the study you check with FEMA to see if they will accept this software. d. Page4- 2. Discuss how the storm volumes compare between the HSPF model and the Hydraflow model i. Hydraulic Analysis, continued -Table 2 -for 100-year storm how can the water level in the upstream collection pond be lower than at the downstream weir? How does this compare with the PCM HEC-RAS output elevations? e. Page 5, Table 4 -is heading If Elevation of inlet" supposed to be If Water Elevation at Inlet"? f. Page 6, Secondary Flow Across Madison Road -at STA 20+44 and 24+41 the drywell outflow rates provided in the table appear to be derived from TP-19 where the soils are SP but the test pits closest to these drywells, TP-20, TP-24 and TP-25, show the soils to be either clay or clayey sand. Please use drywell outflow rates that would be expected from these latter soils. g. Copies of referenced emails from West Consultants h. Please include some discussion about what happens to stormwater generated between the Triangle pond and Madison Road 22. Report Cales a. Include printouts of the input and of the culvert cales for the 100-year run b. 2-year storm run, Haase Pond - i. Is this the South Collection Pond? Page 7 Dev. Eng.: SU8-201S-0001 PAINTED HILLS Floodplain Reviewl -Detailed.docx ii. the orifice coefficient used for the culvert (pipe projecting) is 1.00. Please provide supporting documentation for this value. c. 2-year storm run, Overflow Pond - i. Is this the Forebay Pond? ii. Why does the contour area decrease as the stage increases? iii. Confirm crest length iv. Provide supporting documentation for the exfiltration rate d. 2-year storm run, Discharge Pond - i. Is this the Distribution Pond? ii. The outflow consists of 4 36-inch pipes at elevation 2001.44. What pipes are these? The gravel gallery consists of 18-inch pipes at elevation 1994.56 +/-. These pipes are shown with a 0.5% slope but the plans show the slope as flat, please explain. iii. The outflow is also modeled using a 78' weir at elevation 2007.44. Please explain where this is. e. Gravel Gallery Calc Sheet -provide an exhibit that relates the run (A, B, C, D, E) to the pipe on the plans. 23. Will the gravel gallery pipes, which have no slope, have the capacity to convey the peak flow without backing up the water too much? 24. West half of the gravel gallery system is represented by Geotechnical Evaluation Phase II (lPEC 2015) boring B-9. This boring shows that groundwater is very shallow, 11 feet below the ground surface, which puts the groundwater level near the top of the perforated drywell barrel sections and gravel galleries. These readings were taken in July 2015 in the summer of a declared statewide drought. {Per www.ncdc.noaa.gov, the monthly precipitation totals at Spokane Airport for 6 of the 7 months prior to July (March excluded) were near average to far below average with April and May at about 50% of normal, June at 6% of normal and July at 30% of normaL} We are concerned that if the groundwater is this high during a drought year then during a year that is wet enough to produce a 100-year storm the groundwater level will be significantly higher, high enough to make the drywell and gravel gallery infiltration ineffective. This concern is also applicable to the east portion of the infiltration system where the groundwater in July 2015 was 27 feet below existing ground (boring B-10). In a typical year this Chester Creek branch is flowing meaning that prior to the 100-year storm these flows could saturate the ground also resulting in very high groundwater levels. Please address. 25. Compare the 100-year water surface elevations between the HEC-RAS PCM run and the Hydraflow run. CLOMR Application Report (dated Sept 10, 2015) 26. Page 3 title block -please check the project location figure at the bottom 27. Unnamed Tributary flow -Page 5 says that the total flow for the Unnamed Tributary is 20 cfs but page 10 says it is 16 cfs. Please check. 28. Infiltration facilities - a. Page 9 says that the WCE report is 2014 but it should be 2015 Page 8 Dev. Eng.: SU8-201S-0001 PAINTED HILLS Floodplain Reviewl -Detailed.docx b. Page 10 near the top says that the pond is 215 ft wide by 215 ft long. Confirm that these dimensions are correct. 29. Interior Drainage -Page 13 last paragraph mentions 103 drywells, please confirm this number HEC-RAS Model 30. Confirm that the cross-section spacing and the profile downstream of Thorpe matches the Civil plan Preliminary Geotechnical Evaluation, Phase 1 31. Correct all incidences where P-5 is incorrectly called out as P-2 Preliminary Geotechnical Evaluation, Phase 2 32. Include this report in the FEMA submittal Geotechnical Evaluation, levee Evaluation and Certification (Existing levee between Thorpe and Dishman-Mica roads) 33. Section 2.1 Logs -section mentions previous Geotechnical reports. Please include a description of them in Section 1.4. 34. Section 3.4 -discuss the needed erosion protection for the high velocities (7 ft/s) just downstream of Thorpe Road as shown in the table 35. O&M Manual a. Section 3.10 Operation -forthe financial plan, how much money should be put aside to prepare for fixing flood damage? b. Section 3.20 Maintenance, for the financial plan - i. estimate how many mowings per year and their annual cost. Can 2.3H:1V slopes be mowed? ii. Estimate the frequency and annual cost for tree and objectionable material removal from the levee and creek channel. Geotechnical Evaluation, Proposed levee (levee along east side of Dishman-Mica road) 36. Section 3.4 Closures -note that the proposed access appears to penetrate the levee 37. Section 3.9 and 3.10 -please include the operation and maintenance plan Geotechnical Evaluation, Gustin Levee Evaluation (levee near 40th Avenue) 38. Section 2.2 Site Conditions -mentions fairways, please check 39. Section 3.5 Embankment Protection -FEMA FIS Station appears to differ from the HEC- RAS cross-section station, please include the HEC-RAS stations. 40. Section 3.9 and 3.10 -please include the operation and maintenance plan Page 9 Dev. Eng.: SU8-2015-0001 PAINTED HILLS Floodplain Reviewl -Detailed.docx Biological Evaluation by BSW 41. Section 5.4 mentions restoring the temporary trench area to its original contours but the civil plans show this area being regraded. Please check. Please provide a written response to each comment above to ensure that we properly review any revisions or lack thereof. All submittals must be submitted to the Permit Center. If you have any questions, please email me at hallen@spokanevalley.org or call me at (509) 720-5319. Sincerely, ~U"J/;~ 'Zv~.Allen Development Engineer Copies: • Bryan Walker, C/O NAI Black, 107 S. Howard St., Spokane WA 99201 • Marianne Barrentine, Spokane County Public Works Building, 1026 W. Broadway Ave., Spokane, WA 99260 • Spokane Valley Planning Department -Deanna Horton • Spokane Valley Development Engineering -Project File Page 10 OPERATIONS AND MAINTENANCE PLAN FOR PAINTED HILLS PRD FLOOD CONTROL SYSTEM Owner: Black Realty Inc. Party responsible for Operations & Maintenance: Painted Hills PRD Homeowners Assn. Parent Parcel Number(s): 45336.9191, 45334.0106, .0108, .0109, .0110, .0113, .0114, .9135, 44040.9144 LOCATED IN SECTION 33 & 34, T25N, R44E & SECTION 4, T24N, R44E, W.M. SPOKANE COUNTY, WASHINGTON The above parent parcels contain the Painted Hills PRD flood control drainage and levee system. The residential lot owners, commercial property owners and multi-family property owners of Painted Hills PRD are benefitting from these flood control facilities. The homeowners association of this project is responsible for (details described later): • The continued operations and maintenance, including repair and replacement as needed, of these facilities, • Providing funds to finance the continued operation and maintenance of these facilities, • The administration of this agreement with each property owner being bound by this agreement and with the responsibilities to be shared equally between each Painted Hills PRD property owner, and, • Establishing a maintenance committee and designating a member to be responsible for the administration of this plan. This operations and maintenance plan runs with the land and is binding upon the Painted Hills PRD Homeowners Association property owners, their heirs, successors and assigns. The City of Spokane Valley assumes no responsibility at all for any operations or maintenance of facilities mentioned herein or the administration of this plan. 1.00 PURPOSE This plan is to provide: 1. General operations and maintenance responsibilities for the facilities described herein, and 2. Cost estimates of the assessments to be paid by each property owner mentioned herein for the funding of this maintenance. Page 1 2.00 GENERAL OPERATIONAL CHARACTERISTICS Drainage Facilities The Painted Hills PRD flood control drainage and levee system is intended to collect and discharge stormwater runoff generated by upstream basins and, possibly, stormwater from adjacent properties that has historically flowed into the property and identified on FEMA panel as compensatory storage. The drainage facilities consist of a box culvert under Thorpe Road, a five foot wide concrete channel, a 48” and 60” concrete pipe mainline, manholes, a bio-infiltration swale and a drywell/gravel gallery infiltration field with associated pipe, manholes and headwalls. The system includes 4-18” culverts under Madison Road. A levee along the northerly side of Chester Creek between Thorpe Road and Dishman-Mica Road and then extending along the northerly side of Dishman-Mica Road to Wilbur Road is also a part of the system. A portion of stormwater runoff from the upstream basins south of the project flows in the Chester Creek channel under Thorpe Road continuing northwesterly under Dishman-Mica Road. The levee provides flood protection of the development site from Chester Creek. The remainder of stormwater runoff from upstream basins south of the project flows under Thorpe Road via the box culvert, enters the concrete channel, then flows in the pipe system, through the bio-infiltration swale into the drywell/gravel gallery infiltration field at the north end of the site where the flow is stored and infiltrated into the ground. Stormwater runoff from upstream basins east of the project flows under Madison Road in 18” culverts and outfalls into the 60” pipeline via manholes. It is important to provide adequate maintenance activities to ensure that the flood control facilities remain silt and debris free, as this silt and debris will affect their performance. Additionally, vegetation must be maintained to prevent erosion of the levee. Maintenance details are discussed below in Section 3.0. 3.00 MAINTENANCE REQUIREMENTS AND SCHEDULES Drainage Facilities The drainage facilities consist of several elements including: box culverts, stream channel, levee, concrete channel, storm drain mainline, culverts, outlet structure, bio-infiltration swale, inlet structure, drywell/gravel gallery infiltration field, manholes, catch basins, access roads, headwalls with trash racks and fencing. These elements are located as shown on the attached exhibit. The following describes these facilities and the recommended maintenance. A comprehensive visual inspection of the complete flood control drainage facilities should be conducted twice a year. More frequent inspections for various elements may be required as described below. For long duration storms, greater than 24 hours, the drainage facilities should be inspected during the storm event to identify any developing problems and safely correct them before they become major problems. Signs shall be posted notifying all residents to look for “potential” problems and to notify the homeowners’ association of those observations. In general it is important to provide adequate maintenance activities to ensure that the vegetated areas and structures remain silt, dirt and debris free because accumulations of these will affect the facilities function for stormwater storage volume as well as the ability of the drywells/gravel galleries to discharge Page 2 stormwater. Should these facilities fill up or become clogged, the flood control system will not function as intended putting areas at risk of flooding. Therefore, periodic maintenance is a must. Box Culvert: There are three box culverts adjoining the project site. These box culverts are within the public road right of way and will be maintained by the agency having jurisdiction (AHJ) of the roadway. Any problems noticed while inspecting or maintaining other elements of the system should be reported to the AHJ. Chester Creek and Levee: Chester Creek extends across the southwest corner of the site from Thorpe Road northwesterly for approximately 900 feet where it crosses under Dishman-Mica Road. The creek carries seasonal flows from the foothills to the south. The site is protected from flood flows by a levee along the northerly side of the creek. The creek channel and levee need to be maintained to ensure flood flows are prevented from entering the site. Maintenance of the channel and levee shall be the responsibility of the Painted Hills PRD Homeowner’s Association. Maintenance items include: • Regular mowing, grass should be kept at about 2-4 inches in height, • Removing trash, debris, noxious weeds plus items that reduce the amount of vegetative cover, • Removing any starts of woody vegetation that appear in the channel or on the levee side slopes, • Repairing any holes caused by animals on the levee side slopes, • Inspecting the levee side slopes and channel bottom making sure there are no breaches or breaks or erosion. Immediately repair with a sandy loess soil, compacted in place and follow up after the storm event with seeding or sodding the repair and more substantial maintenance activities if needed, • Repairing mowing damage, • Removing and replacing of the grass and underlying soil if it becomes contaminated to the extent that the grass is not healthy. Concrete Channel: There is approximately 370 feet of 5 foot wide concrete open channel extending from the easterly box culvert under Thorpe Rd to the corner of Thorpe Road and Madison Road. At Madison Road the channel flow enters into a 48” pipe fitted with a trash rack. The channel needs to be maintained to ensure there is no debris or vegetation blocking the flow out of the box culvert and along the channel. Additionally, the trash rack at the end of the channel needs to be kept clear. Maintenance of the channel shall be the responsibility of the Painted Hills PRD Homeowner’s Association. Maintenance items include: • Visually inspecting twice a year the walls and floor surface of the channel for damage or wear that would compromise the channel integrity. • Prior to each rainy season (August or September), inspecting the channel ensuring that there is no debris present. • Following large storm events or rapid snow melt events performing a visual inspection and Page 3 remove any deleterious debris and trash. • Instructing those performing other maintenance functions on the system to report any observed damage to the channel. Storm Drain Mainline: The storm drain mainline consists of 277 feet of 48” and 2174 feet of 60” RCP pipe from the downstream end of the concrete channel at Thorpe Rd and Madison Rd, running parallel to Madison Rd and ending at the bio-infiltration swale at the north end of the site. Additionally, there is 630 feet of 36” HDPE pipe from the downstream end of the bio-infiltration swale to the drywell/gravel gallery infiltration field. The pipes need to be maintained to prevent sediment and trash build-up in the bio-infiltration swale and the drywell/gravel gallery infiltration field. Maintenance of the storm drain mainline shall be the responsibility of the Painted Hills PRD Homeowner’s Association. Maintenance items include: • Annually inspecting the pipe openings on each end to ensure there is no blockage or damage to the ends. • Every three years or after substantial storm runoff, performing a TV inspection of the pipe looking for blockages, damage, etc., • Removing sediment build-up from the pipe, • Repairing any sections of damaged pipe. Manholes & Catch Basins: The mainline pipe system has manholes at pipe junctions and angle points. Along Madison Road there are catch basin connected by pipe to the mainline pipe system to drain overflow from the roadside swales. Manholes and catch basins need to be maintained to prevent blockage of flow within the system. Contact a professional to remove the debris, trash and sediment buildup. HOMEOWNERS ARE NOT TO ENTER THE MANHOLES. Maintenance of the manholes and catch basins shall be the responsibility of the Painted Hills PRD Homeowner’s Association. Maintenance items include: • During routine landscape maintenance of roadside swales, removing any debris from catch basin grates. • Annually inspecting catch basins for trash and sediment build-up and removing trash. • When sediment build-up fills ½ the depth of the sump (about 1 foot), removing the sediment. • Annually inspecting manhole lids and catch basin grates to ensure they are properly seated and are structurally sound. • Every five years, inspecting the structure walls to ensure the concrete walls are in good condition and the joints remain sealed. • Instructing those performing other maintenance functions on the system to report any missing lids or grates. Page 4 Cross Culverts: The cross culverts consist of 18” CMP pipe crossing under Madison Road flowing from east to west in four locations. The culverts connect into manholes on the 60” storm drain mainline. The cross culverts need to be maintained to prevent the reduction of seasonal flows within the pipes. The reduction in flow may be caused by sediment or trash build-up within the pipe or obstruction of the pipe entrance on the east side of Madison Rd. Maintenance of the cross culverts shall be the responsibility of the Painted Hills PRD Homeowner’s Association. Maintenance items include: • Annually inspecting the culvert openings on the east side of Madison Rd to ensure there is no blockage or damage to the culvert end. • Every five years performing a TV inspection of the pipe looking for blockages, damage, corrosion, etc., • Removing sediment build-up from the pipe, • Repairing any sections of damaged or corroded pipe. Bio-infiltration Swale: The bio-infiltration swale consists of a grass lined channel approximately 450 feet long with a 6 foot bottom width and 3:1 side slopes. The swale needs to be maintained to perform the function of removing any remaining contaminants prior to storm water entering the infiltration field. Maintenance of the bio-infiltration swale shall be the responsibility of the Painted Hills PRD Homeowner’s Association. Maintenance items include: • Annually inspecting the channel bottom and side slopes to ensure there is a covering of grass. • Reseeding any bare or dead areas of grass. • Removing any noxious weeds. Drywells/Gravel Gallery Infiltration Field: The drywell/gravel gallery infiltration field consists of four trenches (10’ wide by 13’ deep by 450’ long) filled with rock, 24” pipe running the length of each trench and drywells located at each end and at the middle. The drywells need to be maintained to prevent or reduce sediment buildup in the drywell barrel so as to not reduce infiltration into the surrounding ground. Maintenance of the drywells/gravel gallery infiltration field shall be the responsibility of the Painted Hills PRD Homeowner’s Association. Maintenance items include: • Visually inspecting twice a year the inside of the drywell barrel(s) by removing the lid to look into the structure. Have all debris and trash removed. Sediment must be removed before buildup reaches the bottom of the lowest slot out of the drywell in the barrel wall. Contact a professional to remove the debris, trash and sediment buildup. HOMEOWNERS ARE NOT TO ENTER THE DRYWELL. Page 5 Headwalls/Trash Racks: The trash racks at the headwalls need to be maintained to ensure there is no debris preventing the flow of storm water through the system. Additionally, the trash racks need to be inspected for physical integrity to ensure that no one can enter into the pipe system unless required for inspection/repair. Maintenance of the headwalls/trash racks shall be the responsibility of the Painted Hills PRD Homeowner’s Association. Maintenance items include: • Visually inspecting twice a year the trash racks for damage or corrosion that would compromise the trash rack integrity. • Prior to each rainy season (August or September), inspecting each trash rack ensuring that there is no debris present. • Following large storm events or rapid snow melt events performing a visual inspection and remove any deleterious debris and trash. • Instructing those performing other maintenance functions on the system to report any observed damage to the trash rack. Fencing: The fencing of various system elements needs to be maintained to restrict access to those elements and to protect the public. Maintenance of the fencing shall be the responsibility of the Painted Hills PRD Homeowner’s Association. Maintenance items include: • Visually inspect twice a year the entire fencing system for damaged fence fabric, posts, gates, etc. • Prior to each rainy season (August or September), inspecting each access point ensuring that locks and gates are functional. • Instructing those performing other maintenance functions on the system to report any observed breaches or damage to the fencing. Access Roads/Parking Pads: The access roads/parking pads to various system elements need to be maintained to allow maintenance vehicles access to those elements for periodic maintenance and emergency repairs to protect the public. Maintenance of the access roads/parking pads shall be the responsibility of the Painted Hills PRD Homeowner’s Association. Maintenance items include: • Visually inspecting annually the entire access road/parking pad system for rutting, potholes, etc. Regrade and repair with additional aggregate as needed. • Removing vegetation from the aggregate surface. • Instructing those performing other maintenance functions on the system to report any observed damage to the access roads/parking pads. Page 6 4.00 SINKING FUNDS A sinking fund is an account that is set up to receive regular deposits which are to be used for paying off future costs and debts. The sinking fund monies will be used to pay for planned and unplanned operation and maintenance costs along with certain future replacement costs for the storm drainage facilities. The sinking fund calculation should be revised as necessary to account for actual expenses and changes in rates. In setting up the fund, first the future replacement costs are estimated and then they are converted to annual costs (or deposits) by the following calculations. These calculations assume that the inflation rate is 3% (for estimating the future replacement costs), the typical interest rate is 2% (for estimating the annual costs) and the number of years before replacement is 20. Equations and guidance for using other rates and years can be found in Appendix A. 1) Estimate the value that the item will have in the future when it is time to replace it using the following equation: FV=PV*1.8061, where: FV = future value PV = present value 2) Estimate how much money will need to be deposited each year in a bank account in order to have enough money accumulated in time to pay for the replacement using the following equation. A=FV*0.0412, where: A = annual payment (or deposit) FV = future value (from step 1, above) Sinking Fund Calculation Results: The developer shall provide $25,000 to initiate the set-up of maintenance funds. The following values are the results of the calculations which are shown on the following page. Annual cost for regular operation and maintenance $25,954 Annual cost for replacements $11,894 Total annual costs $37,848 Total monthly costs (= total annual costs /12) $3154 Number of units 580 Monthly cost per lot (= total monthly costs /# lots) $5.44 Page 7 Sinking Fund Calculations REGULAR OPERATION AND MAINTENANCE COSTS Description Units Annual Quantity x Unit Price = Annual Cost Drywell cleaning EA 12 $300 $3,600 Catch Basin cleaning EA 4 $300 $1,200 Mowing EA 4 $2,000 $8,000 Debris removal EA 4 $2,000 $8,000 Channel/Trash Rack inspection EA 2 $500 $1,000 Pipeline TV inspection(3 years-3,053) LF 1018 $3 $3,054 Manhole inspection EA 11 $100 $1,100 Total $25,954 REPLACEMENT COSTS (for more information on calculations in this table see Appendix A) Un its Quantity x Unit Price = Present Value, PV n Inflation Rate, i1 Future Value, FV Interest Rate, i2 Annual Payment, A Drywell(12) EA 12 $4,000 $48,000 20 0.03 $86,693 0.02 $3,572 1/3 Manhole, 84” (9) EA 3 $4,100 $12,300 20 0.03 $22,215 0.02 $915 ¼ Manhole, 60” (2) EA 0.5 $2,500 $1,250 20 0.03 $2,258 0.02 $93 18” Culvert (280) LF 280 $50 $14,000 20 0.03 $25,286 0.02 $1,042 ¼ Catch basin (4) EA 1 $1,500 $1,500 20 0.03 $2,710 0.02 $112 Bio-infiltration swale-seeding (13,800 ) SF 13,800 $0.10 $1,380 20 0.03 2,493$ 0.02 $103 2” Asphalt pathway SY 2340 $10 $23,400 20 0.03 $42,263 0.02 $1,742 6” CSTC Access Rd CY 210 $40 $8,400 20 0.03 $15,172 0.02 $625 Grading Access Rd SF 11,340 $1.25 $14,175 20 0.03 $25,602 0.02 $1,055 Fencing LF 1770 $20 $35,400 20 0.03 $63,936 0.02 $2635 Total $11,894 Notes: n = number of years to replacement LS means Lump Sum, EA means Each, SY means square yard Page 8 IN WITNESS WHEREOF, the undersigned has reviewed the above information and determined it to be appropriate for the improvements proposed for this plan and has caused this instrument to be executed on this day of __________________________, 20____. Signature: Name (print): Title: STATE OF WASHINGTON ) COUNTY OF SPOKANE ) CITY OF SPOKANE VALLEY ) ss I certify that I know or have satisfactory evidence that is/are the individual(s) who personally appeared before me, and who acknowledged that he/she/they executed and signed this instrument and acknowledged it to be his/her/their free and voluntary act for the uses and purposes mentioned in this instrument. Dated this __________ date of ______________________, 20____. NOTARY PUBLIC In and for the State of Washington, Residing at My appointment expires: Page 9 Appendix A The future replacement costs can be estimated and then converted to annual costs (or deposits) by the following calculations. 1) Estimate the value that the item will have in the future when it is time to replace it using an assumed (best estimate) inflation rate and the following equation: FV=PV*(1+i1)n , where: FV = future value i1 = inflation rate PV = present value n = number of years to replacement Example values for the factor: (1+i)n n, years 5 10 15 20 i1 0.02 1.1041 1.2190 1.3459 1.4859 0.03 1.1593 1.3439 1.5580 1.8061 0.04 1.2167 1.4802 1.8009 2.1911 0.05 1.2763 1.6289 2.0789 2.6533 2) Estimate how much money will need to be deposited each year in a bank account in order to have enough money accumulated in time to pay for the replacement using an assumed (best estimate) interest rate and the following equation: A=FV* i2 / [(1+i2)n-1], where: A = annual payment i2 = interest rate FV = future value n = number of years to replacement Example values for the factor: i2/[(1+i2)n-1] n, years 5 10 15 20 i2 0.02 0.1922 0.0913 0.0578 0.0412 0.03 0.1884 0.0872 0.0538 0.0372 0.04 0.1846 0.0833 0.0499 0.0336 0.05 0.1810 0.0795 0.0463 0.0302 Page 10 Development Engineering 11707 E Sprague Ave Suite 106 • Spokane Valley WA 99206 509.921.1000 • Fax: 509.921.1008 • cityhall@spokanevalley.org January 4, 2017 Todd Whipple, P.E. Whipple Consulting Engineers 2528 N. Sullivan Road Spokane Valley, WA 99216 Re: Painted Hills Flood Control Plans Todd, With Dishman-Mica Road, Thorpe Road, and Madison Road Improvements City Project No.: SUB-2015-0001, EGR-2016-0066, & FP0-2016-0007 Review Comments for Submittal #2 Development Engineering has reviewed your submittal of the Flood Control Plans and supporting documents for the above-mentioned project. In our review, it was found that additional information is needed prior to permit issuance. Please see our comments below. Note: SVSS = Spokane Valley Street Standards, SRSM = Spokane Regional Stormwater Manual, ROW= Right of Way General 1. Prior to construction permit release, the following needs to be accomplished: a. Copy of CLOMR from FEMA b. Plan approval 2. Prior to construction acceptance, the following needs to be accomplished: a. Copies of the Department of Ecology (DOE) drywell registrations for all new drywells (submitted with construction certification) b. Record drawings showing as-built condition c. Revisions to HEC-RAS model and reassessment of the freeboard if construction has altered the channels from that depicted in the model d. Letter from design engineers certifying project constructed according to approved plans and specifications e. Levee certifications {44 CFR 65.10 (e)) f. Construction Certification Package Dev. Eng.: Painted HIiis Flood Control Plans -Review 112.docx Flood Control Development Narrative 3. General -please address the requirement for an overflow path for the 100-year storm mentioned in SRSM chapter 2.2.4, paragraph on Infiltration Facilities. 4. Background a. Page 1 paragraph 1-change ... when no flood events occurred ... to ... when no significant flood events occurred ... b. Page 2 -since 40th is an east-west oriented street should references to "east of 40th Avenue" be changed to "north (or south) of 40th Avenue"? c. Change references to "Spokane Rathdrum" aquifer to "Spokane Valley Rathdrum Prairie" aquifer. 5. Main Flow Across Thorpe Road a. Proposed Design i. Box Culvert/Open Channel -the text refers to 2-10" culverts but our records say that they are 18". Please check pipe size. ii. Pipe Mainline -text mentions that along Madison are manholes with sumps but, per WSDOT details, these structures are called catch basins. Please revise. iii. Gravel Gallery System - 1. Paragraph 1-please include the design outflow rates of the drywells and the pipe crosses (may need to provide calcs). 2. Paragraph 2 -The design flow of 64 cfs was at Thorpe, please revise the design flow to what it is at the gravel gallery system. iv. Infiltration Rate - 1. Paragraph 1-why is this paragraph included in that TP-29 is at the south end of the site by Thorpe whereas the gravel galleries are at the north end? 2. Paragraph 2 -please show how the 1.8 x 10·3 cfs/sf design flow rate was derived. 6. Secondary Flow Across Madison Road a. Paragraph 1 i. Second sentence -mention that the flow from the most northerly culvert ends up going into culvert at 30+42. ii. Third sentence -check that the culvert stations listed match those in the table below paragraph 3. 7. Attachments- a. Provide outflow rate calculations for the HOPE crosses. If the head required to achieve the outflow rate is significant then check this water surface elevation as a downstream condition in the channel and pipe hydraulic calcs. b. Open channel calcs -the Q may be a little bit more than 64 cfs when the flow from the two pipes at the upstream end of the channel are included. c. Pipe System calcs - i. Hydraflow is not on FEMA's list of approved software programs. We recommend that before submitting the study you check with FEMA to see if they will accept this software. Page 2 Dev. Eng.: Painted HIiis Flood Control Plans -Review #2.docx ii. Include the two-foot-high level spreader at the downstream end of the system. d. Gravel gallery - i. Confirm source of the infiltration rate. ii. Check totals for the sidewall area and bottom area columns. e. Bio-filtration swale design -the Manning's n of 0.2 is for shallow flow conditions. What depth does King County consider to be "shallow"? The depth calculated in the analysis is over 4 feet. Use a Manning's n applicable to a 4 foot flow depth. Biological Evaluation 8. Section 4.3, paragraph 1 -can a vegetative cover be greater than 100% (top of page 9)7 9. Section 5.3, paragraph 2 -confirm that the items mentioned ( work in channel only when dry, BM P's, spill protocols, minimal peripheral impacts, construction fences) are adequately provided in the construction documents. 10. Section 5.4-confirm that the items mentioned (BMP's, FEMA specifications) are adequately provided in the construction documents. 11. Section 6.2, page 26 -because the levees at the small bridges need to be raised, more than 200' of levee needs to be raised. 12. Section 6.7, paragraph 1, all of the 1% flood is being infiltrated. Operations and Maintenance Plan 13. General: a. This manual needs to be incorporated into the overall O&M Manual for the whole site. b. Include the levee O&M manual from the Geotech Levee Evaluation and Certification report as an appendix. c. Per CFR 65.6(a)(12) mention that the City Manager or designee will be the community official responsible for assuring maintenance activities are accomplished. 14. Page 1: a. Top- i. Spell out what a PRD is. ii. State the party who is responsible for O&M until the HOA is formed. b. Middle, bullet list -add bullet stating HOA is responsible for: Providing annual report each October to Spokane Valley Public Works describing the general status of sinking fund account and also specific inspections, findings and maintenance performed. c. Last paragraph before next section (1.00) -Change to say: The parties mentioned above are primarily responsible for all operations and maintenance of ... 15. Section 2.00, Drainage Facilities (page 2), paragraph 1- a. Second line -remove "possibly" and "that has historically flowed into the property and" Page 3 Dev. Eng.: Painted Hills Flood Control Plans -Review 112.docx b. Provide FEMA panel number and effective date. 16. 3.00 Maintenance Requirements and Schedules: a. Right after this section heading include: All inspections and repairs are to be performed by or directly overseen by a qualified professional per this schedule and following major events. Maintenance tasks are to be performed soon after the need is identified and before facility is to perform unless otherwise agreed to by the City. Repairs or replacements are to be completed immediately upon their identification unless otherwise agreed to by the City. Only qualified individuals may enter confined spaces. b. First paragraph, last line -change "recommended" to "minimum required" c. Chester Creek and Levee - i. Reference the levee O&M manual from the Geotech Levee Evaluation and Certification and include in the appendix. ii. Paragraph 1 - 1. 3rd sentence -add to the end: ... of the creek and along the north side of Dishman-Mica to Wilbur Road. 2. 4th sentence, revise to say: ... maintained to ensure flood carrying capacity is maintained and flood flows are ... 3. Last sentence, revise to say: "Maintenance of the channel and levee and obtaining permits to perform the maintenance shall be II iii. Paragraph 2, Maintenance Items - 1. 1st bullet-Geotech O&M says grass should be 3" high or taller. Include that grass should not be taller than 12" (per the Biological Evaluation) 2. 3rd bullet -at end include that only native grasses are to be on the levee. 3. 5th bullet -after this bullet add the following bullet: * Filling out the levee checklist and include it in the annual report to the City. d. Concrete Channel, first bullet -add to the end of the sentence: ... and repair or replace damaged portions. e. Manholes and Catch Basins i. 1st sentence -revise to say ... mainline pipe system has catch basins at pipe junctions and ... f. Bio-infiltration Swale Maintenance - i. Include mowing? ii. Include removal of accumulated sediments. g. Drywells/Gravel Gallery Infiltration Field -include that every X years the pipe and crosses are inspected by camera for clogging and debris. 17. 4.00 Sinking Fund a. Regular O&M costs - i. Confirm that the annual quantities represent "A comprehensive visual inspection of the complete flood control drainage facilities should be Page4 Dev. Eng.: Painted HIiis Flood Control Plans -Review 112.docx conducted twice a year." e.g. Drywell cleaning is 2x/year so annual quantity should be 24. ii. Mowing -mention which facilities are to be mowed iii. Debris removal -mention which facilities are to have removal iv. Pipeline TV inspection -mention which facilities are to be TV'd v. Manhole inspection -are these the Catch Basins on the trunkline along Madison? vi. Include - 1. levee inspection and maintenance 2. Madison cross-culvert inspection and maintenance 3. Swale reseeding and noxious weed removal 4. Fencing, access roads, parking pads, signs inspection and maintenance 5. Cost to prepare annual report b. Replacement Costs - i. in the first line the manholes are catch basins per WSDOT, ii. include trunkline along Madison and trash racks Preliminary Geotechnical Evaluation, Phase 1 18. Analysis and Preliminary Recommendations -paragraph 2 says that soils good for gravel galleries are in the south part of the site. So, the soils in the north part of the site are not good for gravel galleries? Full-scale Drywell Testing 19. Figure 1-show where the test occurred. Flood Control Plans General 20. Please include the following City project numbers on all plan sheets: a. SUB-2015-0001 (Subdivision) b. EGR-2016-0066 (Engineered Grading Permit) c. FDP-2016-0007 (Floodplain Development Permit) 21. All ROW dedications and easements shall be recorded prior to the use of the frontage improvements and flood control elements. Dedications for flood control elements need to be recorded prior to LOMR submittal with their file numbers entered on the plans. We have received and reviewed (comments sent December 15, 2016) the following for flood control elements: a. an access easement and a drainage easement for the flood control bioswale and infiltration areas, Page 5 Dev. Eng.: Painted Hills Flood Control Plans -Review 112.docx b. a temporary drainage easement (initially called a temporary construction easement) for the storm drain pipe along Madison Road, and c. a drainage easement along Thorpe Road. Please provide draft legal descriptions and exhibits for the following for flood control elements: a. Border Easements along Dishman-Mica that involve a levee, b. Slope easements along levee slopes not covered by a border easement, c. Access easements along levees that are outside the border easement. Please provide draft legal descriptions and exhibits for the following (non-flood control elements): a. ROW dedication at the NE corner of Thorpe and Dishman-Mica, b. ROW dedication at the NW corner of Thorpe and Madison, c. ROW dedication to the BCR's of Roads A through Don Madison, d. ROW dedication to the BCR's of Road E and the multi-family driveway approach on Dishman-Mica, e. Border Easements along Dishman-Mica that don't involve a levee, f. Border Easements along Thorpe and Madison, g. Access easement for Dishman-Mica sidewalk that meanders into site. 22. Based on the street classification and project soil types, a pavement design shall be required for Dishman-Mica, Thorpe and Madison per SVSS Chapter 8. 23. Please submit a striping and signage plan for Dishman-Mica Road. Coordinate with the Traffic Impact Analysis for required left turn lanes and two-way left turn lanes. Show how the two-way left turn lane will taper at the Chester Creek crossing where the pavement section narrows. 24. Please provide a Design Deviation Request for the following: a. Two driveway approaches for Dishman-Mica Road (SVSS 7.8.2.b) 25. For proposed utility adjustments and relocations, the applicant/engineer is required to contact each utility purveyor impacted by the required utility relocations and - a. Discuss with the purveyor the proposed work including relocations and adjustments as well as the costs for these activities, b. Obtain from the purveyor a written statement that they acknowledge and concur with or have alternatives for the needed work, and c. Forward a copy of the statement to Spokane Valley Development Engineering. Receipt of statements will be required prior to civil plan approval. d. Show the location of any relocated utilities. 26. Please submit a drainage report for the roadside swales. Include curb inlet and non- flooded roadway width calculations. 27. Confirm there is maintenance access to all stormwater and levee facilities (SRSM 11.1.6) and provide approaches where accesses connect to a road. 28. If flood flows varied from those modeled and they ended up exceeding system design, for instance at the infiltration/gravel gallery area, will there be any time for response · between the exceedance occurring and properties being inundated? Page 6 Dev. Eng.: Painted H/1/s Flood Control Plans -Review lf2. docx 29. Incorporate into the design the recommendations mentioned in: a. The Biological Evaluation in sections 5.3 (e.g. best management practices, construction fences around minimized work areas, restoration of impacts) and 6.5 (signs). b. O&M Manual, Drainage Facilities section (signs). Sheet C0.0 30. In the 'Dev. Const. lnsp.' contact information section, please revise the phone number to 599-6306 and the contact name to Ken Van Dyk. In the 'Roadways' section, please change the phone number to 720-5008 and remove the contact name. Applies to Sheet C9.0 as well. 31. Make sure all sheet titles match the titles in the Sheet Index. Sheet C0.1 (General Notes) 32. SV Note #6 -change should to shall. Sheet C0.Z (Dishman-Mica Road Sections) 33. For the Dishman-Mica Road Widening Calculations: a. Provide a column that depicts the existing super-elevated cross-slopes and adjust the proposed cross-slopes to match. The minimum proposed cross-slopes shall be 2%, b. Check the Proposed Curb Elevations. 34. For Sections 1 -3, please: a. Label the street centerline, b. Revise the cross-slope of the pavement widening to match the existing super- elevated cross-slopes and provide the range of cross-slopes, c. Verify the pavement section with a pavement design, d. Specify PG 70-28 for the HMA pavement. 35. For Section 1, please: a. Revise the planter strip width to 7' per SVSS 7.5.10, b. Extend the border easement to the toe of the slope or provide a separate slope easement, c. Reference SVSS Standard Plan R-103 for the 6' sidewalk. 36. For Section 2, please: a. List the range of pavement widths, b. Remove the 10' border easement. 37. For Section 3, please: a. Verify the need for the roadside swale, b. Extend the border easement to the toe of the levee slope or provide a separate slope easement, c. List the range of pavement widths, d. Adjust the 34' and 64' dimension strings to end at the ROW, e. For the 8' asphalt path: locate the construction line location and specify the pavement section and a cross-slope. If maintenance vehicles will utilize the asphalt path, verify the width and pavement section. Page 7 Dev. Eng.: Painted Hills Flood Control Plans -Review#2.docx Sheet C0.3 (Thorpe and Madison Road Sections) 38. For Section 4, please: a. Provide applicable stationing for this section, b. Reference SVSS Standard Plans R-102 for the curb and gutter and R-103 for the sidewalk, c. Verify the pavement section with a pavement design. 39. Provide a separate cross section of Thorpe Road that includes the concrete channel. 40. For Section 5, please: a. Provide applicable stationing for this section, b. Provide a pavement and gravel section for the meandering path, note that this path will be used by a vactor truck to clean out drainage facilities, c. Label the range of cross-slopes for the widening per the widening calculations, d. Adjust the border easement width to account for the meandering path, e. Label the varying swale widths to account for the meandering path, f. Label the dimension from the ROW to the centerline of the 60" storm pipe, g. Verify the pavement section with a pavement design. 41. For Sections 4 and S and the roadside swales, include the following or provide a separate swale section: a. 3:1 maximum side slopes, b. 12" treatment soil zone, c. If the following treatment soils are installed, the City of Spokane Va11ey does not require soil testing per SRSM: "For swales and ponds, the top 12 inches of soil shall consist of a thoroughly blended mix of 50% compost with 50% native soils." d. Note requiring swale bottoms and side slops shall be lined with sod/hydroseed, e. Typical bottom dimensions and depth, f. Show a typical drywell or catch basin section with the 6" treatment depth and minimum depth from rim to flowline. Sheet Cl.3 (Site Element Plan) 42. Coordinate the 'Madison Rd Easement Plan' section with Sheet C0.3. 43. Plan view calls out 2-10" culverts under Thorpe but our records say that they are 18". Please check pipe size. Sheets C3.00 -C3.23 44. Reference intersection detail sheet at all applicable intersections. 45. Make sure all proposed and existing ROW and all easements are labelled. a. Where levee is outside the ROW and Border Easements provide access and slope easements. Sheet C3.00 (Dishman-Mica Road P&P) 46. For the sidewalk that extends from Dishman-Mica Road to onsite: a. Provide the station and radius of the curve, b. Provide a plan view that shows the entire alignment of the onsite sidewalk. Page 8 Dev. Eng.: Painted HIiis Ffood Control Plans -Review 112.docx c. Provide finish grade spot elevations that comply with ADA guidelines and include a cross-slope for drainage. d. Show and label the access easement for all portions of the sidewalk located onsite. 47. Please identify the existing hydrant near STA 22+40 and the power pole and telephone pedestal near STA 22+60. Determine if relocations are required. 48. For the new guardrail it will need to extend farther to the south than indicated on the plan due to the posted speed limit and slopes. The curb and gutter does not provide an adequate barrier in this situation. Verify the required length of the guardrail and the clear zone requirements with AASHTO Roadside Design Guide. 49. For Construction Note #10, specify the start STA for the guardrail and reference new guardrail only. 50. For Construction Note #11, specify the start and end stations of the pavement taper. The required taper length shall be calculated per L = ws, where 'w' is the widening width and 's' is the posted speed limit of 45 mph. 51. The Traffic Impact Analysis mentions street lights along Dishman-Mica. Please show the light locations and specify that the lights will be installed with the plat. Specify necessary conduit sleeves to be installed with the frontage improvements. 52. In the profile, adjust the Top of Curb elevations to match the existing super-elevated cross-slopes and the revised Road Widening Calculations from Sheet C0.2. Sheet C3.01 (Dishman-Mica Road P&P) 53. For Construction Note #2, please reference Sheet C0.2. 54. For Construction Note #3, please reference a 'spill' curb, similar to Sheet C3.00. 55. For Construction Note #4, reference the appropriate plan sheet and detail for the asphalt path details. The City does not have specific standards for asphalt pathways. 56. Since the 8' pathway will be driven on, provide adequate turning radii around the approaches. 57. Verify Construction Note #5 for th is sheet. 58. For the pedestrian ramps at Road 'E', provide sidewalks on each side of the Road 'E' to down to the ramps or provide sidewalks from the top of the levees down to the pedestrian ramps. Short sections of adjacent sidewalk at the ramps will be acceptable. 59. Road E -show how stormwater flowing down/along Road E is captured before it gets to Dishman-Mica and is disposed of. 60. For Construction Note #10 please verify the Standard Plan R-113 reference, as it is intended for adjacent sidewalks. 61. For Construction Note #12, please verify the sheet reference. 62. For Construction Note #15, specify the start and end stations of the pavement taper. The required taper length shall be calculated per L = ws, where 'w' is the widening width and 's' is the posted speed limit of 45 mph. 63. For the approach at STA 35+25, show the curb returns and provide pedestrian ramps. Provide sidewalks down to the ramps. 64. Provide Type Ill barricades per SVSS Standard Plans R-142 at each approach and Road 'E' until they are operational. 65. Please provide centerline stations for the driveway approaches at STA 28+75 and 35+25. Page 9 Dev. Eng.: Pain ted Hills Flood Control Plans-Review 112.docx 66. In the profile, adjust the Top of Curb elevations to match the existing super-elevated cross-slopes and the revised Road Widening Calculations from Sheet C0.2. Sheet C3.02 {Dishman-Mica Road P&P} 67. See all applicable review comments from Sheet C3.0l for this sheet. 68. Please remove the extraneous hextag #1 near STA 39+75. 69. For levee and 8' path to be installed on church property from STA 35+82 to 39+80: a. Please provide evidence of granted permission from the church to build on their property. b. Provide access, slope and construction easements. 70. For Construction Note #9, specify the start and end stations of the pavement taper. The required taper length shall be calculated per L = ws, where 'w' is the widening width and 's' is the posted speed limit of 45 mph. 71. Any relocated utilities shall be located outside of the clear zone. 72. For Construction Note #10 please verify the Standard Plan R-113 reference, as it is intended for adjacent sidewalks. 73. Provide Type Ill barricade per SVSS Standard Plans R-142 at the approach until it is operational. Sheet C3.10 (Thorpe Road P&P} 74. In the Left Top of Curb Profile, show all text for the vertical curves. 75. In the profiles, the minimum 'k' value for sag vertical curves is 50 per SVSS Table 7.1. 76. In the profiles, the minimum 'k' value for crest vertical curves is 30 per SVSS Table 7.1. 77. For Construction Note #2, please reference Detail 4 on Sheet C0.3. 78. For Construction Note #6, reference the roadside swale section in the detail sheets, in addition to S-130. 79. Label existing sidewalk to remain between STA's 15+00 and 17+00. 80. Construction Note #7 at STA 11+53.78 should reference a driveway approach with a separated sidewalk. See Standard Plans R-110 through R-112. 81. Identify hextag #10 at each end of the existing sidewalk near STA 15+00 and 17+00. 82. For the change in direction of the sidewalks near STA's 13+90, 14+75, and 16+75, please limit the maximum angle of change to 30 degrees. 83. For Construction Note #17, please locate the drywell near the low point. Maintain 5' of horizontal clearance from the nearest curb inlet. Verify that the drywell rim will be 0.25'minimum below the adjacent flowline elevation. 84. Please provide stationing for all curb inlets. Limit maximum spacing of curb inlets to 100', or less depending on curb inlet calculations. Locate the curb inlets to maximize swale treatment. 85. Roadside swales are considered flat for volume calculations where the swale bottom slope is 1% or less. Address all roadside swales where the street grades exceed 1%. Sheet C3.11 (Thorpe Road P&P} 86. See all applicable review comments from Sheet C3.10 for this sheet. 87. Please provide a Construction Note for the 6' wide sidewalk at the box culvert. 88. Drainage easement to be labelled as permanent. Page 10 Dev. Enq.: Painted Hills Flood Control Plans -Review 112.docx 89. How will large debris lodged in the middle of the concrete channel get removed (say, at station 9+00)? Will equipment need to get down into the channel? If so, how? Provide access road and easement (include file number) along full length of channel? 90. Please provide a curb inlet at low point STA 19+56.36 and near STA 22+75. Provide stationing for all curb inlets. Limit maximum spacing of curb inlets to 100', or less depending on curb inlet calculations. Locate the curb inlets to maximize swale treatment. 91. For Construction Note #14 and the existing drywell to be abandoned, please specify that decommissioning drywells shall comply with WAC 173-218-120 and WSDOT Specs 7- 05.3(2) Abandon Existing Manholes. The following is required: a. Remove any structure within three feet of the land surface, b. Backfill up to three feet below the land surface with material that is uncontaminated, chemically and biologically inert, and that drains equal to or more slowly than the native material surrounding the UIC well, and c. Fill the remaining three feet directly below the land surface with native soil or other structurally sound material common with current engineering practices. 92. For Construction Note #16, please provide Thorpe Road stationing and offsets for each catch basin for construction clarity. 93. In the Centerline/Sawcut Profile, please provide the missing grade break elevations for STA's 23+35.57 and 23+55.57. Sheet C3.12 (Chester Creek Culvert Extension) 94. Please revise the sheet title and Section 'A' title to match the Sheet Index on Sheet C0.0. 95. Please label Thorpe Road. 96. For Section 1, a. Verify the ROW /easement dimensions. Sheet C0.3 shows a ROW width of 55'. b. Reference Std. Plan R-102 for the curb and gutter, c. Reference Std. Plan R-103 for the sidewalk, d. Specify how the curb and gutter will be secured to the precast panels, e. Set the top of sidewalk flush with the top of curb and gutter, f. The 4" HMA is the minimum thickness, it will need to vary to get the cross-slope. g. Specify a tack coat shall be applied to the precast panel decking prior to placing the asphalt paving, h. Provide a guardrail at the north end of the box culvert extension. 97. For Section 2, a. Provide construction details for the precast panel and footings, i. How will precast panel be secured to the existing culvert? ii. Footings need to be at or below elevation of existing culvert footings. b. Why is the FG@CL lower than the top of the precast panel? Sheet C3.20 -C3.23 (Madison Road P&P) 98. In public meetings, street lights were promised along Madison Road. Please show the light locations and specify that the lights will be installed with the plat. Specify necessary conduit sleeves to be installed with the frontage improvements. Page 11 Dev. Eng.: Painted Hff/s Flood Control Plans• Review 112.docx Sheet C3.20 {Madison Road P&P) 99. See all applicable review comments from Sheet C3.11 for this sheet. 100. Please provide stationing for all curb inlets. Limit maximum spacing of curb inlets to 100', or less depending on curb inlet calculations. Locate the curb inlets to maximize swale treatment. 101. Roadside swales are considered flat for volume calculations where the swale bottom slope is 1% or less. Address all roadside swales where the street grades exceed 1%. 102. For Construction Note #9, utilities shall not be located in sidewalks per SVSS 6.2.2 & 6.2.3. 103. Construction Note #14-channel access may need to be shown for the full length of the channel. 104. Construction Note #16 at STA 10+75 should reference a driveway approach with a separated sidewalk. See Standard Plans R-110 through R-112. Sheet C3.21 {Madison Road P&P) 105. See all applicable review comments from Sheet C3.20 for this sheet. Sheet C3.22 {Madison Road P&P) 106. See all applicable review comments from Sheet C3.21 for this sheet. Sheet C3.23 {Madison Road P&P) 107. See all applicable review comments from Sheet C3.22 for this sheet. 108. In public meetings, it was mentioned that the project sidewalk would extend and connect to the sidewalk by the school to the north. Please investigate. 109. For the pedestrian ramp at the southwest corner of Madison Road and Road 'C', please connect the ramp to the 10' asphalt path. Sheet C3.24 (Madison Road Storm Pipe Crossings) 110. For Sections 'A' & 'C', provide a 0.10' min. drop through the catch basin per SRSM 8.5.2. 111. For Sections 'C' & 'O', the soil cover over the culvert appears to be less than 1'. SRSM 8.4.2 requires culverts with soil cover less than 2' to be ductile iron. Soil cover is measured from top of pipe to bottom of asphalt pavement. Increase the soil cover to 1' and provide pipe data supporting the shallow soil cover for a CMP material. 112. Please specify the type of CMP. 113. Provide trash racks at the inlets of all the cross-culverts since the outlet of the 60" pipe has a trash rack. 114. Structures at the 60" RCP should be catch basins not manholes (per the narrative). Please show the sump. 115. Please revise the sheet title to match the Sheet Index on Sheet C0.0. Sheet C3.30 {Intersection Details) 116. For all details, label existing and proposed ROW's. 117. For the Curve Table, please specify that the data is taken at the back of curb. 118. For Detail 1: Page 12 Dev. Eng.: Painted Hills Flood Control Plans -Review 112.docx a. Provide a widened border easement per SVMC 20.20.090, b. Provide curve data and spot elevations for the south edge of pavement, c. Adjust the separated sidewalk location to the back of the ramp, d. Label the gutter slope at the base of the ramp. 119. For Detail 2: a. Rename 'Dishman-Mica Road' to 'Madison Road', b. Provide a widened border easement per SVMC 20.20.090, c. Revise the BCR top of curb spot elevation on Thorpe Rd to match the profile, d. Verify that the gutter slope at the base of the pedestrian ramp is 2% or less. 120. For Details 3-6: a. Revise the BCR top of curb spot elevations on Madison Rd to match the profile, b. Verify that the gutter slopes at the base of the pedestrian ramps and the cross- slope along the crosswalk are 2% or less, c. The longitudinal slope of Madison Rd at each intersection is less than 0.8%. Adjust the Madison Rd BCR top of curb spot elevations to create a 0.80% minimum longitudinal slope without a cross gutter or a 0.50% minimum longitudinal slope with a cross gutter (SVSS 7.5.4) or lower the BCR spot elevations on Roads 'A' -'D' so the intersections slope to the west. 121. For Detail 7: a. Verify that the gutter slope at the base of the pedestrian ramps and along the cross walk are 2% or less, b. Provide the future design of Road 'E', provide curb inlets on Road 'E' at the east BCR's. Sheet C4.0 -C4.2 (Proposed and Existing Levees) 122. To prevent unauthorized vehicular access, provide gates/bollards/etc. at the ends of the levees and where the levees cross approaches. 123. At points along all project levees call out BFE and max required freeboard (44 CFR 65.10 (b}(l} ). Sheet C4.0 (Proposed Levee P&P) 124. Show construction line along levee alignment. Include data to locate the construction line in space when it leaves the road alignment. 125. Call out easements. 126. Profile: a. Label profile. b. Profile should be along top of levee. 127. For Construction Note #1, reference the appropriate plan sheet and detail for the asphalt path details. The City does not have specific standards for asphalt pathways. 128. Approach at 28+80 -there is concern that pedestrians crossing the approach on the levee may not be seen by drivers pulling into the approach. Please look into providing pedestrian crossing of the approach near the road. 129. For portions of the levee that cross the driveways and Road 'E', specify a 2% maximum cross-slope for pedestrians and a thicker pavement section for traffic. Page 13 Dev. Eng.: Painted Hills Flood Control Plans -Review #2.docx Sheet C4.1 (Proposed Levee P&P) 130. See all applicable review comments from Sheet C4.0 for this sheet. 131. In Section 'A': a. show the finish grade being flush with the top of path and cross-slope, b. specify the depth of HMA and what standard it should be compacted to, c. Should the elevation per plan arrow point to the top of asphalt? 132. Levee Construction Notes: a. Note 1-recompact to what standard? b. Notes 2 and 5 -provide titles that match those of the documents being provided. 133. Seeding Note - a. % doesn't add up to 100%, please check. b. Confirm that this seed mix is approved by FEMA (see Biological Evaluation sections 5.4 & 6.2) Sheet C4.2 (Existing Levee P&P) 134. See all applicable review comments from Sheet C4.0 for this sheet. 135. Include a note requiring all non-compliant vegetation be removed per Biological Evaluation section 6.2. 136. Plan View: a. It is anticipated that the whole length of the existing levee will need to be used by vehicles for maintenance. With this: i. Confirm that the 5.5' wide asphalt pathway has adequate width, ii. Verify the turn radii and pavement section for its entire length, iii. At the south end provide a turn-around or continue the path up to the parking lot. b. Move the beginning of the levee alignment to be contiguous with the alignment of the new levee. Identify where 0+00 is located. c. Please revise section references of C4.5 to C4.4. d. Use BFE values per the effective flood insurance study, e. Per CFR 65.l0{b)(l) there needs to be an additional foot of freeboard at the bridges. Please confirm that this is provided, f. Incorporate Geotech recommendations from section 3.4 (Embankment Protection) of the levee Evaluation and Certification report, revised August 29, 2016. 137. Profile: a. Label profile, b. Levee elevation from 5+00 to 5+80 seems too low. Please check. 138. Construction Note 7 -in note for required minimum freeboard check the stations. 139. levee Construction Notes 2 and 5 -provide titles that match those of the documents being provided. 140. In Sections 1 and 2, a. Provide station limits, b. locate the construction line location on the levee, c. Call out a cross slope, Page 14 Dev. Eng.: Pain red Hills Flood Control Plans -Review 112.docx d. Specify a crushed gravel base beneath the asphalt path and compaction standard. 141. If any existing onsite bridges will experience vehicular traffic, please provide a bridge load rating. Sheet C4.3 (Proposed Levee Cross Sections) 142. General - a. Identify where O is located, b. Locate pathway on all sections. 143. Section SL-1-check stations and elevations. 144. Section SL-4-check elevations. 145. Section SL-9 -please revise road name to Road 'E'. Sheet C4.4 (Existing Levee Cross Sections) 146. General -Identify where O is located, Sheet CS.0 (Storm System Overview) 147. Include titles for profiles. 148. For upper profile provide stations for all structures. 149. Construction Notes: a. Provide all applicable details sheets for all notes. b. Note 5 -"manhole" should be "catch basin". Revise standard plan callout and specify depth of sump. Check spelling of "labelled". Sheet CS.1 (Concrete Channel P&P) 150. Plan View: a. Invert elevation of pipe from SO-CB #1 at the channel wall doesn't match the elevation in C5.2. Please verify the pipe slope from SD-CB#l to the concrete channel. b. Include the 100-year stormflow in the system calcs from the pipes originating from SO-CB #1 and SD-CB #2. c. Show the fence located north of the channel in cross section A. 151. Construction Notes: a. Note I -include CS.21 b. Note 4 -include S-121 152. Profile - a. Include slope down to culvert inlet. b. Check stationing on axis. 153. Please provide structural calculations and details for the fence, retaining walls and footings in Section 'A' (loads, dimensions, reinforcing, connections, etc.). Sheet CS.2 (Box Culvert and Channel Details) 154. Box Culvert Detail: a. General -Provide design details for box culvert and wing wall (design loading, dimensions, elevations, thickness, reinforcing, connections, etc.) Page 15 Dev. Eng.: Painted Hills Flood Control Plans • Review 112.docx b. Plan View - i. Drainage easement is permanent not temporary, ii. For culvert alignment line provide a bearing and a station equation where this alignment crosses the Thorpe alignment, iii. Check stationing of wing walls. c. Section 1 - i. Label the ROW, ii. Reference Std. Plan R-102 for the curb and gutter, iii. Reference Std. Plan R-103 for the sidewalk, iv. Specify how the north curb and the south curb and gutter will be secured to the precast panels, v. Set the top of sidewalk flush with the top of curb and gutter, vi. Specify a tack coat shall be applied to the precast panel decking prior to placing the asphalt paving, vii. Provide guardrails at both ends of the box culvert. viii. Adjust the 12' dimension to start at the face of the 6" curb. ix. Verify the precast panel deck thickness with Section 2. x. The 4" HMA is the minimum thickness, it will need to vary to get the cross-slope. xi. For slope down into the culvert inlet - 1. What is the stormwater velocity? 2. Is erosion protection needed? d. Section 2 -bottom of box is alluvial bed. Calculate scour and set footings below scour. 155. Channel and Pipe Connection: a. General -Provide design details for channel and trash rack (loads, dimensions, reinforcing, connections, etc.) b. Plan View - i. There are two set of lines where the channel turns, remove lines that do not represent the channel geometry ii. Provide channel alignment details and location of pipe inlet. iii. Drainage easement is permanent not temporary, Sheet CS.3 (Madison Pipe P&P) 156. Construction Notes: a. Note 3 -Structures at the 60" RCP should be catch basins not manholes (per the narrative). Call out standard plan for catch basins and specify depth of sump. b. Note 5 -is the concrete outlet a pad or slab (see C5.4)? c. Note 7 -specify frame and grate type and include S-121 reference. 157. Plan view: a. Make sure all structures are accessible for cleaning and have a construction note, b. In 60" pipe why is there a structure at 22+45? 158. Profile: a. Provide stations for all structures on concrete pipe, Page 16 Dev. Eng,: Painted Hills Flood Control Plans • Review H2.docx b. Make sure all pipes have length and slope information, c. Provide offset at 60" pipe outlet. 159. For the culverts under Madison Road, Spokane County GIS shows that there may be a 24" pipe near station 23+50. Please check. 160. Include the 100-year stormflow in the system calcs from the pipe originating from SD-CB #6. Sheet CS.4 (Bioswale P&P) 161. Include a short wall at the downstream end of the bioswale as a last trap for sediment. 162. Plan View: a. Clean up overlapping info, b. Provide dimensions/alignment/geometry information for fence, channel and pipes to locate them in space. c. Confirm all structures can be accessed for maintenance. d. Provide all dimensions for hammerhead tum around. e. Provide file number for easement. 163. Construction Notes: a. Make sure all notes have pertinent detail sheets referenced. b. Note 3 -gate should be wider than road. c. Note 9-specify frame and grate type and include S-121. d. Include note for infiltration head wall. 164. Bioswale Inlet Cross Section: a. Provide design details (dimensions, elevations, thickness, reinforcing, connections, etc.). b. Provide details for trash rack. c. In upper drawing check the orientation of the section arrows. d. Include the concrete level spreader in the hydraulic calcs. 165. Typical Bioswale Section A a. Call out minimum depth of section. b. The O&M manual says the side slopes are 3:1, please correct. c. Narrative says bioswale will be seeded not sodded, please revise. 166. Profile -show proposed grade. 167. Include the 100-year storm flow in the system calcs from the pipe originating from SD-CB #7. Sheet CS.5 (Infiltration P&P) 168. Plan View: a. Provide alignment information for pipes and structures to locate them in space. b. Confirm all structures - i. Have rim and inlet elevations and that elevations match those in profile. ii. Can be accessed for maintenance (especially by Vactor per the project narrative). c. Provide structure numbers to relate structures to those in the profile. d. Provide file number for easement. Page 17 Dev. Eng.: Painted Hills Flood Control Plans -Review #2.docx 169. Profile: a. Provide stations at structures. b. Show proposed grade. 170. Construction Notes: a. Make sure all notes have pertinent detail sheets and standard plans referenced. b. Note 7 -specify drywell type. c. Note 8 -specify fabric class. d. Note 9 -provide standard plan. e. Include note for infiltration head wall. Sheet CS.6 (Infiltration Headwall Details) 171. Provide design details for headwall, channel and trash rack (loads, dimensions, elevations, thickness, reinforcing, connections, angles, etc.). 172. Call out spacing between pipes. 173. Provide stations at end of channel and at pipe inverts. Sheet CS. 7 (Infiltration Headwall Details) 174. Drain field cross section -provide complete spec reference. 175. 24" HDPE Cross Detail -specify filter fabric and how it is attached to pipe. Sheet C9.0 (SWPPP Cover) 176. Legend -there isn't a storm drain pond, please revise. 177. Provide protection at infiltration headwall. CLO MR Application Narrative 178. Page 9 & page 14 paragraph 1-mentions that the infiltration facility maximum design flow is 84 cfs. Where was that flow rate obtained? 179. Page 13, end of 2nd paragraph-may want to also reference the Geotech investigation for the latest drywell design which is the document titled "Full-Scale Drywell Testing ... ". 180. Please include page numbers for all the narrative's pages. HEC-RAS model 181. Proposed Madison concrete pipe is initially 4 feet in diameter then goes to 5 feet in diameter but the second pipe in the model is 6 feet in diameter, please revise and update the text in the narrative. 182. At the outlet of the 5 foot pipe include the concrete level spreader (sheet CS.4). Forms 183. Riverine Structures Form -does the new culvert under Thorpe need to be included in one of the C. BRIDGE/CULVERT sections? Page 18 Dev. Eng.: Painted Hills Flood Control Plans -Review 112.docx Please provide a written response to each comment above to ensure that we properly review any revisions or lack thereof. All submittals must be submitted to the Permit Center located at 11707 E. Sprague Avenue, Suite 108. If you have any questions, please email us at criggs@spokanevalley.org and hallen@spokanevalley.org or call 720-5033 for Chad or 720-5319 for Henry. Sincerely, ~37 Development Engineer Copies: h~-tJ!a-- Henry M. Allen, P.E. Development Engineer • Bryan Walker, NAI Black, 107 S. Howard Street, Spokane, WA 99201 • Lynn Schmidt, WA Dept. of Ecology, 4601 N. Monroe, Spokane, WA 99205 • Marianne Barrentine, Spokane County Public Works Building, 1026 W. Broadway Ave., Spokane, WA 99260 • Spokane Valley Planning Department -Deanna Horton • Spokane Valley Development Engineering -Project File Page 19 Public Works Department Spokane County, Washington------------------- Mitchell S. Reister, P.E. --Director I County Enginee1· January 27, 2017 Whipple Consulting Engineers Attn: Todd Whipple, P.E. 2528 N. Sullivan Rd . Spokane Valley, WA 99216 City of Spokane Valley Development Engineering Attn: Henry Allen, P.E. 11707 E. Sprague Ave., Suite 106 Spokane Valley, WA 99206 RE: Painted Hills PRD Floodplain/CLOMR Submittal Review #2 Dear Mr. Whipple and Mr. Allen, Thank you for the opportunity to review and comment on the proposed Painted Hills PRD in the City of Spokane Valley. We appreciate the coordination and support in our efforts to insure that the proposed floodplain revisions meet the requirements of FEMA and both jurisdictions flood protection ordinances. Not only are some of the flood control facilities located within the unincorporated area of Spokane County but due to the proximity of the development, impacts could occur in unincorporated Spokane County in any case. Spokane County Public Works (SCPW) concurs with the comments of the City of Spokane Valley (CSV) dated 1/4/2017. The SCPW has also performed a preliminary review of the floodplain submittals and CLO MR application including HSPF and HEC-RAS model files received from Whipple Consulting Engineers, Inc. (WCE) on October 14, 2016. We have reviewed the proposed Spokane County floodplain modifications for compliance with the Spokane County Flood Damage Protection Code (SCC 3.20) and the Spokane Regional Stormwater Manual and also reviewed the proposed floodplain modifications within the CSV for impact to property in the jurisdiction of Spokane County. Prior to grading and construction permit issuance from Spokane County, a CLOMR from FEMA will be required. The comments below must be reviewed and addressed before we can complete our review and sign off on the CLOMR application. DEVELOPMENT SERVICES GENERAL COMMENTS The Golf Course overflow branch of the floodplain could run a flow higher than anticipated from the hydro logic modeling due to some of the following conditions: 1) A truly historic Hsupra-design" event. -----------1026 West Broadway Avenue • Spokane. WA 9'3260-0170 Painted Hills PRD Flood,J/bYi),Ctd~u1;1r7nM'iW~wtlf-(pE}gt/ fZJ51655 • TDD: (509) 477-713:.3 v-Jww.SpokaneCounty.org 1/27/2017 2) Unexpected flood basin response from unconsidered antecedent conditions such as a combination of snowpack over frozen ground similar to the conditions present right now. 3) Upstream diversion from the main channel to the overflow path due to undetected physical changes, poor maintenance, or rash actions during a flood emergency with unintended consequences. 4) Poorer than expected actual performance of the infiltration facility at the time of an anticipated or unanticipated flood event. The first three items are, of course, not the regulatory or lega I obligation of the stormwater design or Initial development, respectively. However, the reality of such a possibility is still there and we are dealing with the elimination of a floodplain and full urban development over it. Since the proposal is a fully artificial means of handling the flood flow, the potential backwater dynamics from the proposed infiltration facility should be summarized and provided for In the following recommended ways. Back-Water Behavior Revise the WCE Painted Hills Flood Control Narrative report dated 07/23/15 to include: a) The ultimate back-water behavior from any surcharging of the 60" pipe thru the four Madison Road cross-culverts and the subsequent filling and any escape from the east road ditch. Consider revising the WCE Painted Flood Control Plans dated September/2016 to include: b) An overland relief from the intake of the 60" pipe back to the Chester Creek main channel. Pipe in-flows exceeding its "flowing full" capacity Oust below the pipe crown) can't be further accepted anyhow, so it would seem to be best to get the excess water to the main channel rather than show up elsewhere. So long as this relief channel can't operate below the "flowing- full" and flood event levels, this would seem to be permissible and approvable. Outflow Behavior Re-write the Infiltration Rate section in the 07 /23/15 WCE Painted Hills Flood Control Narrative report and amend the supporting geotechnlcal Information In the following ways: 1. Delete the mention of TP-29 and the Type A and B drywells, which aren't relevant to the current design. 2. Mention confirming Borings B-1 & B-2 from the 04/19/16 IPEC report that appear to be within or near the footprint of the infiltration facility. Show the boreholes relative to the planned facility. 3. In the 06/28/16 IPEC report, the location of the tested drywell needs to be shown and its depth clarified (a Type 2 is mentioned). Show the tested drywell relative to the planned facility. 4. In the above same report, IPEC needs to show the derivation of the design discharge rate from the full-scale drywell test for the actual drywells shown on the plans. Drywells with both 3 and 4 active barrels are shown. 5. In the above same report, application of a 1.1 FOS in mentioned. Is this adequate for the unusual and major application versus that envisioned in the "Spokane 200" method? 6. IPfC not WCE needs to derive the unit rates of infiltration for the actual gravel galleries shown on the plans. 7. On Sheet CS.7, the 24" HOPE cross discharges into the galleries need to be reviewed and concurred with by IPEC. 8. IPEC needs to perform a mounding analysis for the infiltration facility from the design flood event, as surmised in their 04/19/16 report. Painted Hills PRD Floodplain/CLOMR Submittal Review #2 -Page 2 of 6 1/27/2017 GUSTIN DITCH FLOOD CONTROL FACILITY 1. The recorded drainage easement is blanket in area and generic in nature respectively, and unspecified as to its goals and terms. Furthermore, it must be recognized that the easement is located on private property and benefits only Spokane County, so the use of it to specifically benefit the PRD property within the City of Spokane Valley is not a given right. 2. In light of the above situation, the proposal needs to show a public benefit within Spokane County. Such a demonstration could be to Illustrate how the interception of the flood flows also removes the floodplain encumbrance over the intervening properties still within Spokane County between the triangle property and the subject PRD development. 3. Based upon the IPEC report dated October 14, 2014 which evaluates the site for drywell disposal, we have no concerns regarding the suitability of the site for the intended drywell farm. However, a report addendum is being requested that comes to a conclusion that the proposed infiltration facility will have no probable, significant adverse impacts to the residential properties In the plat located north of the triangle property including the swimming pool located in the tip of the triangle property. Although this is intuitively obvious due to the fact that the pond bottom elevation is below the swimming pool bottom elevation or any potential basements in the adjacent subdivision homes, this needs to be documented as part of the design considerations. 4. The recorded drainage easement is limited to the property below "contour 2002" per its legal description. WCE needs to clearly identify the 2002 elev. of the existing site contours. 5. Per term 3} the easement doesn't allow excavation "below finish elevation 1995" while the finished pond bottom of the constructed facility is proposed at elev. 1990. 6. Some re-orientation of the impoundment portion of the facility is needed due to the above elevation encroachments upon the easement restrictions. 7. The floodplain entry into the proposed infiltration facility should be culverted instead of an open channel in order to preserve a prescriptive access path around the east side of the pit area to the rear of the property. 8. See attached mark-up with comments for the Gustin Ditch Operations and Maintenance plan. MADISON RD 1. The changes are limited to the PRO frontage and Madison Road ROW, a city street. The existing old culverts are being replaced by those of equal or greater capacity, as to their ideal and actual conditions. The new culvert intakes are shown around the crowns of the proposed large conveyance line meaning there will be little to no back-water impact if the infiltration facility operates as intended. The flow dynamics from any unplanned surcharging of the large conveyance line would fill the ditch along the east side of Madison Road then escape overland across the roadway at its effective low points back into the PRD. This situation would not affect properties east of the Madison Road ROW within unincorporated Spokane County. CLOMR REPORT/CLOMR FORMS/GENERAL FLOODPlAIN COMMENTS 1. Page 9 of the CLOMR Application prepared by West Consultants notes that the levee south of Thorpe Road is not planned to be certified. What happens if there is a failure of this levee-does it result in more flow to the Golf Course Overflow channel? If so, the channel/pipe system/infiltration facility may need to account for this failure. FEMA has specific requirements and a process for modeling levees that are not certified. Discussions with FEMA regarding the certification of this levee should take place and be documented. Painted Hills PRD Floodplain/aOMR Submittal Review #2 • Page 3 of 6 1/27/2017 2. We suggest WCE investigate maintaining an overland path running west from the new box culvert back to the main flood channel. This would operate only should the large conveyance line become surcharged and would relieve any supra-design flows due to changes caused by sedimentation or levee failure at the upstream crossings/channel/levee, an unexpected flood basin response, or truly historic flows that would over-tax the infiltration facility. 3. The proposed 3-foot by 30-foot cutvert under Thorpe Road is acting like a bridge rather than a culvert. The HEC-RAS model shows the water surface at the top of the bridge opening with very minimal freeboard. Additional freeboard for this crossing should be evaluated. 4. The response to general comment #1 of Spokane County's comments from January 11, 2016 notes that the maintenance of the Triangle Pond/Gustin Levee should be eventually taken over by the owner of the future development in the County. This work primarily benefits the Painted Hills PRD, thus Spokane County believes the City of Spokane Valley should be ultimately held responsible for facility maintenance and an appropriate CSV official listed in the O&M manual. Also, any future development plans are speculative and therefore cannot be addressed at this time. 5. The response to CLOMR Application and Report #1 of Spokane County's comments from January 11, 2016 notes that the County should "address the blockage of the culvert at the private driveway immediately". We appreciate West Consultants reviewing the partially blocked culvert in the current state. This is a private driveway crossing and is not the County's responsibility to maintain, nor does the County have a drainage easement for access. The channel/pipe system/infiltration facility should be designed with a factor of safety to account for an increased flow to the Golf Course Overflow reach due to the cutvert sedimentation and any additional flows that may go to the Golf Course Overflow reach. An overflow channel or similar should be explored to handle increased flows to the Golf Course Overflow reach if there are increased flows that the pipe system cannot handle. At this time the County is not interested in pursuing additional survey and modeling to account for the flow split to be provided in this CLOMR application and it is our understanding that FEMA standards would model the culvert without sediment, in case. 6. Appendi)( A (FEMA Forms) a. Riverine Structures Form -Please review the bounding cross-sections for the Thorpe Road Culvert (Replacement) as they don't match those in the PCM HEC-RAS model. b. Riverine Structures Form -Please include the new culvert that will be replacing the three culverts under Thorpe Road. 7. Appendix H (Revised Floodplain Boundaries Flood Profile Floodway Data Table) a. The Revised Floodplain Boundaries map is hard to read and does not appear to be revised. Please review and provide accurate Post FIRM mapping with a useable scale and be sure that it accurately incorporates both the 100-and S00-year events. 8. Appendix I (Floodplain Workmap for CLOMR) a. The floodplain work maps for the CLO MR are missing some of the cross-sections and elevations around the triangle pond and the concrete channel and pipes along Thorpe and Madison Roads. These should show the effective floodplain limits as well as the proposed floodplain limits. 9. Appendix K (Painted Hills Flood Control Development Narrative) - a. Review the number and size of the current culverts that cross under Thorpe Road. Our records show three CMP culverts. Painted Hills PRD Floodplain/CLOMR Submittal Review #2 -Page 4 of 6 1/27/2017 b. Please explain/show how the 1.8 x 10·3 cfs/sf design flow was derived as the infiltration rate for the gravel galleries. c. Please e><plain the duration for the above infiltration rate and consider an event based model to address this as well as volume impacts. d. Please discuss the volume and porosity of the infiltration at the gravel galleries. e. The 100-year storm is noted as 64 cfs for the gravel gallery system; however, this flow does not account for the flows entering the pipe system from the East side of Madison Road. Please review and revise the calculations to include these flows. f. Please check the stationing listed in the Secondary Flow Across Madison Road. Also, the 100-year storm flows for the Madison Rd culverts need to be incorporated into the HEC- RAS proposed model. g. The Hydraflow Storm Sewer program used for the pipe system is not currently on the list of approved software programs from FEMA. Please address. h. A legend should be incorporated for what the different line colors represent on the Storm Sewer Profile from the Hydraflow software. PAINTED HIUS FLOOD CONTROL PLANS & HYDRAULIC MODEL 1. Sheet Cl.3 -Verify the number and size of the culverts under Thorpe Rd. We have pictures of three CMP culverts under Thorpe Rd. 2. Sheet C3.10 -Te><t is hidden for the left top of curb profile. Please fix. 3. Sheet C3.12 -The Chester Creek box culvert roadway width and culvert width on the plans does not match that of the CEM and PCM plans in HEC-RAS. Please review and fix. 4. Sheet C4.1-Check the year on Note #5 for the IPEC report. 5. Sheet C4.2 -Note which study and River Station these BFE values correspond to. Also note what Floodplain E><tent is called out ... current effective or proposed? 6. Sheet C5.0-A 60" concrete pipe is noted on the plans. However, in the CLOMR report (page 14) a 6-foot diameter culvert is called out. The HEC-RAS PCM model also uses a 6-foot diameter culvert. The culvert size information contradicts each other between the plans, the CLOMR report, and the HEC-RAS model. Please revise accordingly to be consistent. 7. Sheet CS.2-Culvert detail B-2 shows a culvert width (in direction of flow) of42 feet. The PCM HEC-RAS model deck/roadway width shows 22 feet. Please review and revise to match. The downstream culvert invert elevation in the plans does not match that of the PCM HEC-RAS model. Please review and revise. Please provide scour calculations for this culvert and confirm footings will be below the scour depth. 8. Sheet CS.4 -The bioswale inlet cross section does not adequately show what the concrete level spreader looks like. Please provide an additional view that captures the concrete level spreader. 9. Both the CEM FW and PCM FW HEC-RAS model for the Golf Course reach has cross-sections where an artificial boundary for the water surface elevation and energy grade line Is created due to the lack survey data specifically at RS 2863 and RS 1981. Please review and extend the cross- sections so an artificial boundary is not created. 10. The Main Channel Bank Stations for the Golf Course reach of the CEM, CEM FW, PCM and PCM FW models do not appear to be correct as they appear to be the stations at each end of the cross-section. Please review. Painted Hills PRO Floodplain/CLOMR Submittal Review 112 -Page 5 of 6 1/27/2017 GUSTIN DITCH FLOOD CONTROL PLANS & HYDRAULIC MODEL 1. Sheet C4.0-The invert elevations on the three-foot culvert addition does not match the invert elevations in HEC-RAS for River Station 1450. Please review and revise. 2. The Manning's n for the bottom of this culvert at RS 1450 is provided as 1 In HEC-RAS. Explain why a manning's n value of 1 is used. 3. There appears to be inconsistencies between sheet C4.0 and HEC-RAS for the levee elevations and base flood elevations as they do not match. Please review and revise. 4. A levee is not shown in HEC-RAS for RS 0 but Sheet C4.0 notes a levee elevation at this location. Please review. 5. Sheet CS.0 -Please label and map the proposed BFE for the triangle pond. Please add the sections and BFE's for RS-20 and RS-36 and show on the plan. Thank you for allowing us to review this submittal. If you have any questions, please don't hesitate to contact me at 477-7443 or mbarrentine@spokanecounty.org. We are also available to meet with either CSV staff and/or Developer engineering staff to discuss these comments further if requested. Sincerely, Marianne Barrentine, PE, CFM Environmental Programs Manager Email copies: Todd Whipple, Whipple Consulting Engineers Ken Puhn, West Consultants Paul Nelson, IPEC Lynn Schmidt, ECY Henry Allen, CSV Deanna Horton, CSV Carrie Koudelka, CSV Mitch Reister, SCPW Chad Coles, SCPW Matt Zarecor, SCPW Gary Nyberg, SCPW Jane Clark, SCPW Julie Shatto, SC B&P Painted Hills PRD Floodp/ain/aDMR Submittal Review #2 -Page 6 of 6 1/27/2017 OPERA TIO NS AND MAINTENANCE PLAN FOR GUSTIN DITCH FLOOD CONTROL SYSTEM Owner: Bar 4 Bar, Inc. & Timothy and Joanne Comer Party responsible for Operations & Maintenance: Painted Hills PRD Homeowners Assn. Parent Parcel Number(s): 45344.9108, 45343.9052 LOCATED IN SECTION 34, T2_5N, R44E, W.M. SPOKANE COUNTY, WASHINGTON The above parent parcels contain the Gustin ditch ana levee drainage system. The residents of Painted Hills PRO are benefitting from these flood control facilities. The homeowners association of the Painted Hills PRD project is responsible for (details described later): • The continued operation and maintenance, including repair and replacement as needed, of • th~J}sJ)i.ti~A&-,h,tq /J~M 17~,t c:./{d,lf;t!!,~ d~H~~q,,..., • Prf>VfcMtg iuntls to'ifnam:e ilie continbcd operation an<f ma:intenance oftl1ese facilities, ./ 4 • The administration of this agreement with each resident being bound by this agreement and with the responsibilities to be shar~d ~ually bptween each P4igted Hills PRD J.>Wpe1:ty • owner, and, /rt?A Cb111111,tl&!, c.1/A.l".f"da wdlf C)Vd,'4'// "ftt/11~"4,llc~ ,,,d. • Establishing amtenance committe and designating a member to be responsible for the Gv.s/i,, d'~ administration o c1-eJU!at I, b,r This 9perations and maintenance plan runs with the land and is binding upon tl1e Painted Hills PRD Homeowners Association property owners, their heirs, successors and assigns until such time as the Gustin property (Parrel No. 45344.9108) develops and then the owner of that parcel will assume responsibility for this plan. Parcel No. 45343.9052 is covered by a storm drainage easement granted to Spokane County as recorded in Book 659 Page 1803. Spokane County assumes no responsibility at all for any operations or maintenance of the faciliti~ -~ • mentioned herein or the administration of this plan. +-Sft?/4:t.tl~ CG-"u,,& tJ-C.0:$ V ,?J,fi!!/7,r~r 1.00 PURPOSE ""'~[:zd: 'f.~~ l14-6t? g~~as~ r~Jt/!J; ti,,.,-,:betPH~ . • ~1 ltN!-ctJ. tlf$p~11 ,-.~4,,,.~hle.y ,:~~~ b~f-1>1 Thisplan1stoprovide: ~llld' 5~ Jl/t:.l,fl"~ ~I' /'(!.~IJ. ~ A'e, _~ t!f.~ ~t,~ 1. General operations and--ff1aintenance responsibiliLies fortbe"facilities aescrioedl1er~1n, 'tl.f~ · ~ 2. Cost estimates of the assessments to be paid by each property owner mentioned herein for the funding of this maintenance. 2.00 GENERAL OPERATIONAL CHARACTERISTICS Drainage Facilities The Gustin ditch and levee drainage system is intended to collect and discharge stormwater runoff generated by upstream basins and, possibly, stormwater from adjacent properties that has historically flowed into this ditch. The drainage facilities consist primarily of a 36" culvert outfall, a 3 foot bottom width ditch. a levee along the south side of the ditch, an existing gravel (borrow) pit (pond) and 18 drywells. Stormwater runoff from the upstream basins is routed under Hwy 27 through a 36" culvert into the ditch where the storm water flows to the west. At the west end of the ditch the storm water flows into the bottom of the existing borrow pit and infiltrates through the bottom of the pit. During larger stonns the storm water will overflow into the drywells and infiltrate into the ground. It is important to provide adequate maintenance activities to ensure that the drainage facilities remain silt and dirt free, as this silt and dirt will affect their performance. Additionally, vegetation must be mainta:b1ed vent eros'ia' of the levee. Maintenance det~ils ..L , / are discussed below in Section 3.0. -----l'IPTe/0$/d~ .6ur _ ./-/dN,I 3.00 MAIN'IENANCEREQUIREMENTSAND CHEDULES Drainage Facilities l'~.5/r'l ?-frd,w 1 tv17A1il cl, 4:,1,(lf~.,/ ff'CM /Jui/4 .. V., t?!-ck4✓ //d. /~fa'frdJl?~"4/ ./r&.. r.s'1r"r.,b ✓11"'4'1~;J.:, .. The drainage facilities consist of a 3 6" culvert outfall, a 3 foot bottom width ditch. a levee along the south side of the· ditch, an existing borrow pit (pond) and 18 drywells and are located as shown in the attached exhibit. The followin_g describes these facilities and the recommended maintenance. . ~IM 4_$.~r ~r 7 A visual inspection of the drainage facilities s110uld be conducted ea~ Forfo";';g{iu'ltiol c-vb YM;6 .,. storms, greater t.ban 24 hours, the drainage facilities should be inspec'ted·tl~gthe storm event to ~«Ai"/&' /I/ identify any developing problems w,d safely correct them before they become major problems. V-b~/ "'~Y,1,., J-ill general it is important o provide adequate maintenance activities to ensure that the vegetated IJt!,178-1 areas and structures renwi.i1 silt, dirt aud debl'is free because accumulations of these wiU affe~t 1he '/e !J:?$ J ditch's and pond's function for stonnwater storage volume as well as the abjlity of the drywell:i to . ~l,ll ~ : discharge stormwater. Should these facilities fill up or become clogged, the only remedy would be-I# n~ to remove the material. Therefore, periodic maintenance is a must. Page2 Ditch with Levee: The culvert outfall needs to be maintained to ensure there is no debris or vegetation blocking the ,.,1( 1. flow out of tl1e culvert. The ditch needs to be maintained to eos'U!;e a strong, healthy, dense /" ,,tf ~~ vegetative cover and that it is free of debris. Maintenance of the ditch and outfall shall be the (,A/ -1fl .- responsibility of the Painted Hills PRD Homeowner'sAssocjation unti.l such time as tl1e Gustin -ltJ property (Parcel No. 45344.9108) is developed. At that tjme the owuer(s) of the new development l shall assume responsibility for mrufitenance of the ditch and le_vec. j ~ f if ~f llt If . Maintenance items include: I~ tj! I~ fi'J • Regular mowing, grass should be kept at abour@iches in height, • Removing trash, debris, noxious weeds plus j~hat reduce the amount of vegetative cover, • Removing any starts of woody vegetation that appeat in tl1e ditch or on~ 1:2.e side '-/,Ji :l_ _ slopes, butt'. ,;,4 _:,, a11d Hl,(.lfl4U &1?/7.v,.,__,, S1'';"" o~ ll '':Y • Repairing any holes caused ~infals on the levee side slopes, wNk C4'f!.V .5 rl/4Jftl4'h Slflf • Inspecting the ditch side slopes, levee side slopes and bottom making sure There are no ' ~ reaches or breaks or erosion. Immediately repair with a sandy loess soil, compacted in _ IA µfe-place an~ foU~w up after tb~ ~t~r~ event with seeding or soddhig of the repair and µ_iore .(" v¥• ~ substantial maintenance acttv1t1es 1f needed, J.., J,./1 . . • Repairing mowing damage, r//P1 ~/1',1 • Removal and replacement of the grass and underlying soil if it becomes contaminated to •tt\ vii the extent that the grass is not healthy. Pond & Drywells: At the borrow pit the pond bottom needs to be maintained to ensure there is no debris; vegetation or sediment preventing the infiltration of storm water through the bottom of the pond. Also, that no .. : debris, vegetation or sediment buildup rise to a level that would allow it to enter into the drywells. J--{ DryweJJs need to be maintained to prevent or reduce sediment buildup in the drywell barrel so as to jtJ'' not reduce infiltration into the surrounding ground. Maintenance of the pond and drywells shall be {I;,~~~ the responsibility of the Painted Hills PRD Homeowner's Association until such time as the Gustin -f,p I"' property (Parcel No. 45344.9108) is developed. At that time the owner(s) offue new development shall assume responsibility for maintenance. Maintenance items include: • Periodically visually inspect the grate and remove any deleterious debris and trash. • Biennially visually inspect the inside of the drywell barrel(s) by removing the grate to look into the stl'llcture. Have all debris and trash removed. Sediment must be removed before buildup reaches the bottom of the lowest slot out of the drywell in the barrel wall. Contact a professional to vacuum out the debris, trash and sediment buildup. HOMEOWNERS ARE NOT TO ENTER THE DRYWELLS. :v , l/~ 1~?k.,"f 11~~- Page 3 4.00 SINKING FUNDS A sinking fund is an account that is set up to receive regular deposits which arc to be used for paying off future costs and debts. The sinking fund monies will be used to pay for planned and unplanned operation and maintenance costs along with certain future replacement costs for the storm drainage facilities. The sinking fund calculation should be revised as necessary to account for actual expenses and changer•.~+ CP~dtk,i,1, Ut/ f-. At _s/4~ /~ f !fr ,d ~ ~/4u,)~ ✓:. In setting up the 'tltlu, · fast the future replacement costs are estimateo ana then they are converted to annual r deposits) by the following calculations. These calculations asst 1~inflation rate fr3% !for estimating tl1e future replacement costs), the typical interest ra,i 1s 2% {!P~stimating theGum-wf costs) and the number of years before replacement is 20. Equatioi:fa.and-guidance for using other rates and years can be found in Appendix A. 1) Estimate the value that the item will have in the future when it is time to replace itusing the following equation: FV=PV*l.8061, where: FV = future value PV = present value 2) Estimate how much money will need to be deposited each year in a bank account in order to have enough money accumulated in time to pay for the replacement using the following equation. A=FV*0.0412, where: A= annual payment (or deposit) FV = future value (from step 1, above) Sinking Fund Calculation Results: The following values are the results of the calculations which are shown on the following page. Annual cost for re Jar o eration and maintenance $10,500 $7,076 Total annual costs $17,576 Total monthl costs ( = total annual costs /12 $1,465 Number of units 580 Monthly cost er unit = total monthl costs/# units) $2.53 Page4 Sinking Fund Calculations Debris removal ff~nuM1_e,y d~.,,,tty >t-f/id Ylir. fPP~!t}t or vll'Y ~el Unit Annual Price = Cost $250 $4,500 $500 $2,000 $1,000 $4,000 Total $10,500 REPLACEMENT COSTS {for more information on calculations in this table see A;e1!endix A} Unit Present Value, Inflation Units Quantitvx Price = PV n. Rate, ii Drainage Structures LS 18 $4,000 $72,000 20 0.03 6" CSTC Access Rd CY 221 $40 $8,840 20 0.03 Grading Access Rd SF 11,400 $1.25 $14,250 20 0.03 Notes: n = number of years to replacement LS means Lump Sum, EA means Each, SY means square yard Page5 Future Value, Interest Annual FV Rate, h Pa:Yfilent, A $130,040 0.02 $5,358 $15,966 0.02 $658 $25,737 0.02 $1,060 Total $7,076 IN WrfNESS WHEREOF, the undersigned has reviewed the above information and determined it to be appropriate for the itnprovements proposed for this plan and has caused this instrument to be executed on this _____ day of _________ ___, 20 __ . Signature: _________________ _ Name (print): ________________ _ Title: ;-10/4 STATE OF WASHINGTON ) COUNTY OF SPOKANE ) CITY OF SPOKANE VALLEY) ss l certify that I know or have satisfactory evidence that ______________ is/are the lnclividua l(s) who personally appeared before me, and who acknowledged that he/she/they executed and signed this instrument and acknowledged it to be his/her/their free arid voluntary act for the uses and pUl])Oses mentloued in this instrument. Dated this ____ date of _________ ., 20 __ . NOTARY PUBLIC In and for the State of Wasbington, Residing at ___________ ~ My appointment expires: _______ _ Pagc6 Appendix A The future replacement costs can be estimated and then converted to annual costs (or deposits) by the following calculations. I) Estimate the value that the item will have in the future when it is time to replace it using an assumed (best estimate) inflation rate and the following equation: FV=PV*(l +ii)°, where: . . FV = future value ii = inflation rate PV = prese:nt value n = number of years to replacement Example values for the factor: (1 +i? n,, ears 5 10 15 20 it 0.02 1.1041 1.2190 1.3459 1.4859 0.03 1.1593 1.3439 1.5580 1.8061 0.04 1.2167 1.4802 1.8009 2.1911 0.05 1.2763 1.6289 2.0789 2.6533 2) Estimate how much money will need to be deposited each year in a bank account in order to have enough money accumulated in time to pay for the replacement using an assumed (best estimate) interest rate and the following equation: A=FV* h/ [(l+h)°-1], where: A = annual payment FV = future value h = interest rate n = number of years to replacement Example values for the factor: hi[(] +h)"-11 n, ve2rs 5 10 15 20 h 0.02 0.1922 0.0913 0.0578 0.0412 0.03 0.1884 0.0872 0.0538 0.0372 0.04 0.1846 0.0833 0.0499 0.0336 0.05 0.1810 0.0795 0.0463 0.0302 Page7 WCE No. 2013-1166 August 20, 2018 City of Spokane Valley 11707 E Sprague Ave, Suite 106 Spokane Valley, W A 99206 Attn: Mr. Henry Allen, P.E. Whipple Consulting Engineers, Inc. Re: Painted Hills Flood Control Development Narrative Dear Henry: AUG 2 0 20'8 CITY OF SPOKANE VALLEY This letter is provided as a description of the flood control plan associated with grading and site improvements that would be completed in conjunction with a future mixed-use development on approximately 99.S-acres of a former golf course property located at 4403 S Dishman-Mica Road. It is intended as an update to previous flood control narrative descriptions provided to the City by Whipple Consulting Engineers dated July 23,2015, October 13,2016, and July 6, 2017. Since the date of the last narrative provided to the City, the applicant has modified the proposed site design in order to obtain a Conditional Letter of Map Revision -Fill (CLOMR-F) from the Federal Emergency Management Agency (FEMA). This design update to obtain a CLOMR-F approval represents a change in the FEMA re-map effort for the project, which was formerly designed to revise the FEMA mapping through a Conditional Letter of Map Revision (CLOMR) process resulting from levee improvements and levee certifications. This change to a CLOMR-F was implemented due to concerns raised by the City at a meeting held on November 901.2017 wherein long-term levy maintenance was questioned by City staff. A call between FEMA representatives, WCE, WEST, and City staff occurred on January 18, 2018. The project site is located within the area identified as Storage Area 1 (SAl) in the effective FEMA Flood Insurance Study (FIS). SA 1 is designated as a compensatory storage area. Within a compensatory storage area loss of flood storage capacity due to placement of fill must be mitigated with an equivalent compensatory volume of storage or through a reduction in flows such that the net condition causes no adverse impact to the base flood or floodway elevations within the storage area. In addition, loss of infiltration capacity due to placement of fill or impervious surfaces must be mitigated in such a way that the decrease in infiltration capacity will cause no adverse impact to the base flood or floodway elevations within the storage area. The overall purpose of the "compensatory" requirement is to ensure that development activities do not cause an adverse impact on flood elevations within the storage area, or downstream of the development (e.g. increasing downstream flows due to reduced infiltration capacity within the storage area). With the current plan to pursue a CLOMR-F, the applicant is proposing to control and manage floodwaters and address compensatory storage requirements on the site through a combination of on-site fill, enhanced conveyance facilities (culverts) and infiltration galleries. Chester Creek main channel with the exception of a small extension of the culvert at Thorpe Road due to widening will remain unchanged. The intent of the Painted Hills PRD flood control design is to mimic the flood control project that Spokane County did on the Chester Creek mainstem, when the Kokomo area was taken out of the flood plain, by digging two deep borrow pits just West of Dishman-Mica Road and South of281h Avenue. 21 South Pines Rd .• Spokane Valley, WA 99206 ,~ PO Box 1566 • Veradale, WA 99037 Phone 509-893-2617 • Fax 509-926-0227 • WhippleCE.com • Info@WhippleCE.com Civil, Structural, Traffic, Survey, Landscape Architecture and Entitlements Painted Hills Flood Control Development Narrative (Storage Area #1 & #6) August 20,2018 Page 2 of6 This narrative restates and clarifies background information regarding the FEMA mapping for the site and further describes the current proposed plan. MAPPED FLOODPLAIN CONDITIONS History of Site Flood Analysis A hydrologic and hydraulic analysis for Chester Creek Basin was completed by Michael Baker Jr., Inc. and approved by Spokane County in a letter to the Federal Emergency Management Agency dated August 6, 1990. There are no long-term gage records for Chester Creek. The limited gage measurements on Chester Creek were collected near the Dishman-Mica Road crossing of Chester Creek for December 1994 through March 1995 and November 1995 through February 1996 when no significant flood events occurred. In February 2006, the hydraulic analysis for Chester Creek was revised by WEST Consultants, Inc. under a FEMA contract. The analysis established updated flood magnitude-frequency estimates for the watercourse. A steady flow hydraulic model has been developed for Chester Creek. 1 The reports concluded that spring floods in the upper Spokane River basin are due to snowmelt runoff from high elevation watersheds. Such floods are of less significance on Chester Creek because of the lower elevation of the water shed limit and the size of the snowpack. Spring runoff occurs about a month earlier with the more gradual rates than on the Spokane River. Nearly all maximum annual flood peaks on Chester Creek occur during the winter. Warm winds and rain can melt the snow rapidly. When winter rain causes snowmelt on partially frozen soil conditions, short-duration, intense runoff generates a flood peak during winter storms. During the more extreme events, Chester Creek runs over its banks filling localized depressions in the flood zone. 1 The duration of flooding is generally between 100 hours and 1000 hours, or between four days and forty days with smaller events occurring with greater frequency than large events. 1 Channel geometry for Chester Creek was developed from surveys conducted in March 2003. Overbank geometry was developed from topography developed by TerraPoint (2003). Flood plain boundaries for Chester Creek and the Unnamed Tributary to Chester Creek were delineated using 2-foot contour interval maps developed by TerraPoint from LiDAR data. 1 A watershed plan for Chester Creek was previously designed with management recommendations for drainage, flooding, water quality, and riparian habitat. As a result, flood control improvements have been implemented along Chester Creek. The improvements to the area began at the Painted Hills Golf Course. In 1998, a project to install new culverts and extensive dredging ofthe channel between Thorpe Road and Schafer Road was implemented. Two large volume borrow pits were constructed downstream. Each pit was designed for the retention and infiltration of Chester Creek floodwaters up to a 25-year event. One borrow pit for the unnamed Tributary to Chester Creek was constructed just north of E 40th Avenue and the other borrow pit for Chester Creek just West of Dishman Mica and South of281h Avenue. Before the storage areas #1 (compensatory area) and #6 (triangle pond) are to be modified (see Site Element Plan), it is important to understand where they are within the Chester Creek Basin, and what floodwaters they receive. Within the Chester Creek Basin, the storage areas are generally located in the northeast corner of the basin along the edge of the valley floor. Specifically, north of Thorpe Road and along Madison Road (Storage Area 1) and to the northeast of 40lh Avenue (Storage Area 6). The flood condition flows, as identified by WEST Consultants, are separated into three parts in relation to the three directions of flow that enters into the Painted Hills Development: the main flow (Golf Course Overflow Reach) across Thorpe Road, the secondary (Unnamed Tributary) flow from Highway 27, and the secondary flow across Madison Road. The project is proposing to redirect the anticipated flows of the l J ...J Painted Hills Flood Control Development Narrative (Storage Area #1 & #6) August 20,2018 Page 3 of6 identified flood events for storage area #1 (main flow and Madison secondary flow) to a discharge point at the north end of the development and for storage area #6 (Unnamed Tributary) to an existing offsite discharge point to the east of the development. Storage Area #1 (compensatory area) is a large storage area that encompasses the majority of the former Painted Hills Golf Course as well as areas to the east of Madison Road. There is no outflow route for this storage area so it is classified as compensatory storage and is allowed to infiltrate through the native soils and into the Spokane Valley Rathdrum Prairie Aquifer. The soils below the storage area include the Spokane Valley Rathdrum Prairie Aquifer as its base followed by layers of course sands that are topped by soils of an alluvial fan or an area of natural deposit from Chester Creek, before the creek was channelized. The floodwaters that enter Storage Area #1 are identified on the July 6, 2010 FIRM Map as the Chester Creek Golf Course Overflow. The Chester Creek Golf Course Overflow originates at a point to the south of Thorpe Road where there was at one time a breach in the man-made channel of Chester Creek. The breach was reportedly from a lack of maintenance and the overgrowth of vegetation in the main channel that blocked the main channel during a storm event. This flow of floodwater enters the storage area from the south at a low point in Thorpe Road through three 15" culverts and, if flow is larger, by overtopping Thorpe Road. Storage Area #6 (triangle pond) is a smaller storage area that is located east of 40tl1 Avenue primarily within a 30-foot-deep gravel pit that was excavated during the early development years of Spokane Valley. Spokane County obtained a drainage easement over the pit in 1983 for storm drainage (flood flow) purposes. The overflow route of storage area #6 is along the south side of 40tl1 Avenue and flows into Storage Area #1 via culverts under Madison Road. The soils below the storage area include the Spokane Valley Rathdrum Prairie Aquifer as its base followed by layers of course sands and gravels that were further exposed by the gravel pit excavation. The Main Flow Across Thorpe Road Concept Design and Process For the concept design the 100-year event was used to size facilities. When reviewing the Geotechnical Evaluations, Phase I (December 31,2013 -Revised August 29,2016) and Phase IT (July 23,2015) it was evident that there are "valley gravels" or well-draining soils that lead directly to the Spokane Valley Rathdrum Prairie Aquifer under the poor draining soils that cover the site. Therefore, we concluded that if we conducted flood waters into these well-draining soils the flood waters may be treated and discharged. Through extensive review, analysis and confirmation from geotechnical evaluations, it was determined that gravel galleries at the north end of the proposed development represented the optimal location for floodwater infiltration due to the fact that the groundwater depth in this location is much deeper than other locations on the site. See Supplemental Geotechnical Evaluation by IPEC dated April 19, 2016. Proposed Design See Site Element Plan in the attachments. 1 00 Year Flood Event There is currently a shallow channel to the South of Thorpe Road that conveys the flood water flow from the breach North to Thorpe Road. This 1 OO-year flood event, known as the Golf Course overflow Reach has a peak flow rate of 64 cfs, at the crossing of Thorpe Road, based on the existing FEMA FIS. Since the levee on the east side of Chester Creek immediately downstream of Thorpe Road is not certified to protect against the 100-year flood, a peak flow of 91 cfs will be used as the l Painted Hills Flood Control Development Narrative (Storage Area #1 & #6) August 20, 2018 Page 4 of6 design flow at Thorpe Road instead of the 64 cfs in the effective FIS . The larger 91 cfs flow is more conservative and simulates additional flow that could be contributed to the Golf Course Overflow Reach from the main channel of Chester Creek in the event of a failure of the non-certified levee (without-levee scenario). This provides a conservative design flow which accounts for a potential levee breach or additional overflows that could occur due to the continued mainstream Chester Creek Channel issues, primarily a lack of upstream channel maintenance, which could result in additional overflows. In addition to the overflow from Chester Creek the hillside above Madison Road has a peak design inflow of 15 cfs through the four operational 18" culverts of Madison Road. Therefore, the total peak 100-yr event flow rate used for conveyance and infiltration design for Storage Area #1 is 106 cfs. System Summary On the south side of Thorpe Road, the waters from a 1 OO-year without-levee flood event, the 91 cfs peak flow rate, is proposed to enter a box culvert on the south side of Thorpe Road. The box culvert has a capacity of216 cfs. From the box culvert the floodwater enters an open channel to a sloped headwall that holds two 48" concrete pipes. Each pipe has a capacity of 77 cfs for a total capacity of 154 cfs. The two 48" pipes extend north from the headwall along Madison Road, with manholes strategically placed to connect to the existing 18" culverts in Madison Road. This connection allows the design flow rate of 15 cfs from the Madison hills to be added to the 91 cfs, for a total design flow rate of 106 cfs. The two 48" pipes end at a vertical headwall where the floodwater splashes out onto a concrete pad and flows across a level spreader into a sloped biofiltration swale. The biofiltration swale cross section has a capacity of 269 cfs. Within the biofiltration swale the suspended solids are stripped out by the tall grasses. At the end of the biofiltration swale is a settling pond that allows the floodwater to settle and rise 1 foot in elevation before flowing over a 20-foot-wide rock weir into the infiltration pond that is 2 feet below the elevation of the rock weir. Within the infiltration pond the floodwater can begin to infiltrate through the pond bottom. When the floodwater in the infiltration pond rises 1 foot in elevation the floodwater will crest over the rim of the 48 drywells and fall into the infiltration trench where the floodwater will then infiltrate into the native soils and enter the Spokane Valley-Rathdrum aquifer. The infiltration trenches have a design capacity of 162 cfs. As demonstrated the flood control system has the capacity to handle the peak 100-yr event without-levee flood design flow rate of 106 cfs with a Factor of Safety of 1.53+/-. The following are descriptions of each design element in more detail. Box Culvert/Open Channel The Golf Course Overflow Reach flows coming from the upstream flow split on Chester Creek is anticipated to approach Thorpe Road as it currently does at the low point in the Thorpe Road profile where there are currently three IS" culverts within the natural drainage way of the Golf Course Overflow Reach. The flow will then enter into a 30-foot-wide by 3-foot-high box culvert under Thorpe Road, replacing the 3 existing culverts. The roadside ditches along Thorpe Road will be regraded to ensure positive flow toward the box culvert. Given the topography of the area, aside from shallow puddles caused by upstream localized depressions, all stormwater will enter into the proposed box culvert. The flow will exit on the north side of Thorpe Road and enter into a concrete open channel with a concrete bottom and vertical concrete walls and then flow to the sloped headwall of the two 48" Pipes. Pipe Mainline At the terminus of the open channel the flow will enter into a two-pipe, parallel, buried pipe system with WSDOT Type II catch basins along the East side of Madison Road. Once inside, the two 48" concrete pipes the flood flow will continue to the north end of the project with an outfall into a bio- filtration swale. Each WSDOT Type II catch basin will have a sump for the settling of particles in low l 1 Painted Hills Flood Control Development Narrative (Storage Area #1 & #6) August 20,2018 Page 5 of6 flow conditions. These particles or silt can then be vactored out of the manholes as part of the routine maintenance, prior to reaching the bio-filtration swale. Bio-filtration Swale (Channen/Settling Pond The bio-filtration channel receives the flood water upon discharge from the two 48" concrete pipes. The filtration will be planted with tall dryland grasses. The flow ofthe floodwater overland through the tall grass provides an initial phase of silt and solid removal before the floodwater flows into a settling pond where additional silt will settle before cresting over aI' rock weir with 8" minus rock compacted in place. Bio-infiltration pond The crested flood water from the settling pond then flows into an open surface bio-infiltration pond. Within the infiltration pond the suspended particles will continue to decelerate and settle downward to the pond bottom while the clear surface water crests over the rim of the drywells that leads into a gravel gallery system only when the floor dictates. Assuming that the infiltration pond discharges at the rate of 1.6xl0-4cfs/sfthe pond bottom in a non-frozen ground event would discharge (61 ,000xl.6xl 0-4) 9.76 cfs directly to the underlying soils, and not enter the drywells. Therefore, a flow represented by 9.76 cfs is generally consistent with a pre-project flow over Thorpe Road of 0.25' or 3 inches, which has been experienced once during the preparation of this project and documented on February 17,2017. The gravel gallery system is for the ultimate disposal into the aquifer, its fmal destination. See Bio-infiltration worksheet in the attachments. Gravel Gallery System Once floodwater flows exceed bottom infill rates it will rise to a depth of one foot and enter the discharge drywells which will evenly distribute the floodwater through gravel galleries by either flowing through the drywell barrels or distributing through the interconnected 12" perforated pipes and galleries along the pond's entire length. The gravel gallery system is based upon a system of 10-foot wide by 10-foot deep infiltration trenches with 3 trenches at 340 feet, a trench at 330 feet, and a trench at 100 feet. the trenches are lined with geo-fabric per WSDOT Std. Spec. 9-33.2(1) and filled with gravel drywell material in conformance with WSDOT Std. Spec. 9-03.12(5). Within the top 3 feet ofthe infiltration trench runs a 12" perforated pipe at a 0% slope that connects the trench drywells within each trench segment. As treated floodwater crests over the rims of the drywells, the floodwater fills from the bottom up, and equalizes throughout the trench. Once filled the gallery is at its maximum design infiltration rate of 162.64 cfs (see gravel gallery worksheet in the attachments). For analysis the 100-year storm has a peak flow rate of 91 cfs, plus the 15 cfs from the Madison Hills for a total design peak flow rate of 106 cfs. So, with a design outflow rate over 1.5 times greater than the design inflow rate the system will adequately discharge the 100-year flood. This is a conservative measure of protection. Infiltration Rate A full-scale drywell test was performed at the north end ofthe site. Based on this test we used the design flow rate of 1.8 x 10-3 cfs/sf for design of the gravel galleries in the open space area north of the proposed Cottages residential area. See attached IPEC Geotechnical Report dated June 28,2016. Maintenance of the pipe, bioswale, road and gravel gallery system is a semi-annual inspection of the gallery through the system drywells looking for a build-up of sediment and debris, and if needed, the removal of the sediment and debris by a vactor truck. SecondarY Protection l J l Painted Hills Flood Control Development Narrative (Storage Area #1 & #6) August 20,2018 Page 6 of6 As a secondary measure of protection, a detention facility is proposed at the south end of the project in the park area. A 176, 181-sf area located in the park area has been lowered 3 feet +/-from the existing ground surface. This area will be covered with grass turf and will function as park open space, with gentle 3: 1 side slopes for easy access. If for whatever reason an emergency situation exceeds the capacity of the pipe headwall or if the 48" concrete pipe inlets are blocked by debris, floodwater is intended to crest over the open channel wall and flow into the park as a temporary containment measure. The detention facility has an outlet located in the NE Comer. The outlet is a catch basin with a rim elevation placed 1 foot above the bottom of the park. The catch basin has an 18" pipe that connects into the western 48" concrete Pipe that runs along Madison Road. Below the rim ofthe catch basin the detention facility has a holding capacity of 178,699 cf or 4.1 O-acre feet, at a final grade of 5 ft depth the detention facility has an ultimate holding capacity of 943,866 cf or 21.67- acre feet. While the detention facility is not the ultimate disposal point for flood water the detention facility provides a secondary containment that will detain the floodwater and drain flood water back into the flood control system without risking a flood of the subdivision streets. Project Site Fill and Flood Protection Measures The project site is protected from the main channel of Chester Creek by the existing levee type fill of property along the existing Chester Creek channel and along Dishman-Mica Road. As was originally proposed and noted the project was going to be a levy type flood control project. However, it has since been modified to strictly a fill project where all future building pads will be placed 1.0 feet above the Base Flood Elevation (BFE). The new fill elevation is proposed to be placed 1 foot or more above the Chester Creek Base Flood Elevation (BFE) and then be graded out to the existing elevation toward Madison Road. Regardless of the grade back, all building pads will be placed above the BFE and certified to FEMA during the development. Therefore, it is incumbent upon the reader to understand that the grading plan of the project site will be to raise the surface. So that all residential building pads will be at least 1.0 foot above the BFE and will therefore always be out of the floodplain, even if the discharge measures experience some catastrophic failure of infiltration during a flood event. D . El eSlgn ements Box Open Pipes Bioswale Settling Rock Pond Drywell Infil. Culvert Channel Pond Weir Trench Width/Area 28' 28' 48" 6' 7,172 sf 2' 61 ,004 sf 48" 10 Length 45' 18' *2,629' 334' -20' --*1,450 Slope 0.5% 1.0% 0.26% 1.0% 0.0% 0.0% 0.0% -0.0% Depth 3' 6' -6' 6' 5' 7' 18' 10' Elev: inlbtm 2007.58 2007.36 2007.18 2000.04 1996.80 1997.80 1995.80 1996.80 1978.8 Elev: Out 2007.36 2007.18 2000.24 1996.80 -- --- *Indlcates a total The Secondary Flow Across Madison Road: The flow across Madison Road is divided into 5 basins from the heights above and to the east of Madison Road that correspond to the 5 culverts that are placed under Madison Road. The most northerly culvert does not have an outlet on the west side of Madison Road. Therefore, the floodwater that should enter this culvert goes to the south to the culvert at Sta 30+42. The floodwaters on the east side of Madison Rd distribute along the east side of Madison and appear to be separated into the four culverts that cross Madison Road at Stations (S to N) l3+22, 20+44, 24+41 and 30+42. As the development proposes to widen Madison Road on the west side, the 4 culverts will be replaced and extended. Since the proposed l Painted Hills Flood Control Development Narrative (Storage Area #1 & #6) August 20,2018 Page 7 of6 inverts of the extended culverts will fall below the proposed grade of the roadside swales, the culverts will connect into the East 48" pipe. The storm water along the west side of Madison Road will be collected in roadside swales where it will receive treatment. The swales will have catch basins with the rim set 6" above the swale bottom. Any excess treated flow that does not infiltrate and exceeds a 6" depth will enter the catch basins. The catch basins will be connected to the East 48" mainline pipe. West Consultants provided the following 100-year storm flows for each culvert during the 100-year storm. We are using these flows to size and design floodwater facilities. STA. 100 Year Storm Flow (cfs) 13+22 4 20+44 1 24+41 1 30+42 2 38+98 7 Total 15 Any floodwater generated west of the triangle pond along E 40th Avenue flows to the west. Then at Madison Road it flows south between the road and the easterly hillside. These flows will be intercepted with the replacement culverts installed at Stations 13+22 through 30+42 that are connected at manholes into the east 48" pipe. The Secondary Flow From Highway 27 (Spokane County) Proposed Design The existing and documented 16 cfs flood flow from Highway 27 (Unnamed Tributary) is currently conveyed via a 36" culvert (limiting factor) that empties into a ditch that flows West across the Gustin property (Parcel No. 45344.9108). The stormwater flows through the ditch and into the existing County borrow pit within the triangular parcel located northeast ofE 40th Avenue (Parcel No. 45343.9052). The existing ditch has been maintained over the years by the property owner (Gustin) to ensure that whatever floodwater comes out of the culvert under Highway 27 will be conveyed to the existing borrow pit. With this or a separate project the ditch will be replaced with a 36" pipe that extends from Highway 27 to the proposed infiltration (triangle) pond bottom in barrow pit. With the pipe there is no potential for floodwater to flow in the natural drainage way to the West. The existing pond is anticipated to be regraded with 18 drywells being installed. Design Elements: Proposed Pond 17,060 sf@El: 1990.00; 35,812 sf@El. 1995.00; 84,416 sf@ El. 2000.00 Drywell spacing 30', total drywell outflow 18.0 cfs, negates pond bottom, frozen ground flow Maintenance Access Road: 6" gravel, max grade 10%, min. radius 35' Fenced with gate Infiltration Pond WCE proposes to improve the outflow of the (triangle pond) borrow pit by regrading and expanding the lowest bottom area of the borrow pit and installing 18 double depth drywells into the bottom of the internal pond. The drywells will provide outflow during a frozen ground condition. Each double depth drywell will provide a design outflow of 1.0 cfs for a total of 18 cfs per the recommendations in the Geotechnical Evaluation by IPEC dated October 14, 2014. n.U~UM "'V, "'v ~o Page 8 of6 If you have any questions or comments in regard to this letter please feel free to contact us at (509) 893-2617. Sincerely, WHIPPLE CONSULTING ENGlNEERS, INC. TRWlbng Encl: Attachments CC: File , J l I ~ . 1 J J ATTACHEMENTS Bibliography Site Element Plan (Sheet Cl.3) 1 00 Year Flood Event Flows Thorpe Road Crossing Madison Hills Flow to Culverts Gustin Pipe Flow to Culverts System Capacity Box Culvert Madison Pipe Bioswale Trapezoidal Channel Storage and Discharge Pond Summary Worksheet Gravel Gallery Worksheet -North Bio-filtration Channel Worksheet Geotechnical Reports BIBLIOGRAPHY 1) Dawes, Larry. August 30, 2016. Biological Evaluation, Buffer Averaging, and Habitat Management Plan for the Painted Hills PRD. Biology Soil & Water, Inc., Spokane Valley, WA. 12-13. l -, .J J PAINTED HILLS PRD BIOLOGICAL EVALUATION, BUFFER AVERAGING, AND HABITAT MANAGEMENT PLAN Spokane County Tax Parcels #45336.9191 and 44041.9144 July 20,2015 (Revised August 30,2016) Biology Soil & W te 9 Inc. l J BIOLOGICAL EVALUATION, BUFFER AVERAGING, AND HABITAT MANAGEMENT PLAN for the PAINTED HILLS PRD Spokane County Tax Parcels #45336.9191 and 44041.9144 July 20,2015 (Revised August 30, 2016) Retained by NAIBlack Contact Person: Bryan Walker 107 S. Howard St., #500 Spokane, WA 99201 509.622.3593 (m) 509.623.1000 (0) bwalker@naiblack.com Investigated by Biology Soil & Water, Inc. Contact Person: Larry Dawes, Principal Biologist 3102 N. Girard Road Spokane Valley, WA 99212-1529 Phone 509-327-2684 Email: bswinc@icehouse.net l l I J J BIOLOGICAL EVALUATION, BUFFER AVERAGING, AND HABITAT MANAGEMENT PLAN for the PAINTED HILLS PRD Spokane County Tax Parcels #45336.9191 and 44041.9144 July 20, 2015 (Revised August 30, 2016) 1.0: Introduction Biology Soil & Water, Inc. (BSW) was retained by Black Realty to complete a Biological Evaluation (BE) and Habitat Management Plan (HMP) for the proposed Painted Hills Planned Residential Development (PRD) located in the City of Spokane Valley, WA. South Dishman Mica Road defines the west boundary of the site, E. Thorpe Road defmes the south boundary of the property, S. Madison Road defmes the East boundary, and developed private property defines the north property boundary (Figures 1-3). The Painted Hills Golf Course formerly occupied this location. The former club house is being renovated to expand the existing restaurant and the remainder of the site will become residential development and open space. The subject property is comprised of seven separate tax parcels including a 91.25 acre parcel where 580 residential units are proposed, and an 8+ acre parcel on the south end of the site that will be designated as a wildlife travel corridor. The Action Area was defined as a half mile radius of the 93+ acre Project Area so the site investigation would characterize adjacent areas where listed species could inhabit or be impacted by the project. This assessment addresses all Critical Areas and listed Priority Habitat and Species including Threatened, Endangered, Proposed, and Candidate Species in the Project Area. The USFWS and NMFS species lists were accessed on their web sites on 4/2112015 and updated August 29, 2016. No NMFS species are listed for the vicinity. The USF&W list indicated the potential presence of the species and critical habitat(s) shown in Table 1 (and in Appendix 1). Table 1. USFWS listed species and critical habitats potentially :>resent in the vicinity of Species ESUIDPS Federal Status Designated Critical Habitat Bull trout Salve linus confluentus Columbia River DPS Threatened Yes Water howellia, Howellia aquatilis Threatened No Spalding's silene, Silene spaldingii Threatened No Canada Lynx, Lynx canadensis Threatened No Yellow-billed cuckoo, Coccyzus americanus, Threatened No The undersigned investigated the Project and Action Areas on March 1, March 29, and April 19, 2015. The conclusions of this plan are based on an evaluation of habitat and species data for Spokane County compiled by State and Federal jurisdictions, an evaluation of construction plans and specifications for the proj ect, a literature review, and field investigations by the author of this report. The project will have no effect on Bull Trout or proposed Bull Trout Critical Habitat. The project will not result in the destruction or adverse modification of potential, designated or proposed Critical Habitat or Essential Fish Habitat for any fish species. The project will have no effect on the threatened species Water howellia, Spalding's silene, Canada lynx, or the Yellow-billed cuckoo. There will be no significant adverse effect on any listed Species of Concern. The site plan includes an 8+ acre wildlife travel corridor for deer and elk and over 30 acres of open space. 1 l ~ J I/Meou e:r fSi3nd Topo USA® 8 Nanal~'O.( -~. -'RiCl1monal'J 'Burnaby . '" \. SUlre~,. .~an~ley "~Vhile.Roclq: .. _._._._!.~I!'!?~J~19!.q_._._._._._._._._._._._._._._._ . .:.'-'-'-'-'-'-'-' -'-'-'''''-'-'-'-'-'-'''''''''''''-'''''-'-'-'-'''''-'-'-'-'-'r''''' ........ _._._._."\._.,.-._.-._ ......... _-_._. 'L ~:'4"~--I I "'!91:[!h&')~, -, ?.o:: Lak~'® ' ~1 " Is 3nd "", -, i 0 .... 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"" i -.- Tapa USA® 8 \ \ " TN ~ MN (14.7"E) -' l J ~ ~: '" " ,:~ l'~ BUILDING RESTRICIONS I§S -.... UIt IID1lIIC1ICIII I#ft.V ~ -~~ -.v m~w...~~ [€I ~V":"~LOCII ~I!I~-= r:';;!,.IU.V UNIT/LOT DATA Iif"Il't CJ 1! QiQE wa» D 2m ,. 30 _ 131 110 42 WWZ' 0 N ,. 1I • 3D ,. 20 24 I 1 I 1 I 1 1 l F 1 1 '-':' -------ti~ -- (U1 1ll' ) . 11' .. 0: • IJO It. MULTI-FAMILY 11.9SAC. PROJ _I """" DRAWN: RCVlan:o: L 'I \' 1:J.11t10 !WCE _,a au> r'''''''J COIO.lU.oIIlO'LUG h-"'or.mIlt:..\!,~Ujn:.ro TRW :"I .... Jl..t:vkU·v.,\ m'e. '01 uorn~ur .... \d .... ~.:1 ---------, ,;~I,'~---I I I I I :~-.-.:~-.-:.1''';;;;''( \ . I ! '._.1 I _-1\ I _" P R D PAINTED HILLS SITE 1 LAYOUT (PRO) DISHMAN.MICA RD. SPOKANE VALLEY,WA --. "'-.. ~ ... SHEET 1 OF 1 .. .'OBt.UUBER 13-1166 J The Project Area does not meet any of the Department of Natural Resources (DNR) criteria for High Quality Terrestrial Habitat. Washington Department of Fish and Wildlife (WDF&W) maps (Appendix 2: Critical Areas Maps) indicate the subject property falls within an Elk polygon (WDF&W Priority Habitat). An 8+ acre wildlife travel corridor is proposed along the entire south end of the project and the corridor will be enhanced with vegetative plantings to accommodate animals traveling through the area. Chester Creek and its associated 100-foot buffer bisects the SW comer of the property. Buffer Width Averaging is proposed to compensate for the encroachment of two lots and foot paths in the riparian buffer. The impact mitigation also includes riparian buffer enhancement. The existing buffer is almost totally devoid of woody vegetation because it was previously a driving range andlor maintained golf course fairway. An evaluation of streams and wetlands is included in this report. 2.0: Methods of Investigation The north parcel of the Project Area is located in Sec. 33, T25N, R44E and the south parcel is located in Sec. 4, T24N, R44E of Spokane County, W A (Figures 1-3). Biology Soil & Water, Inc. (BSW) investigated the property on March 1 and 29, and April 19, 2015 for wetlands, riparian habitat, and species protected under the Federal, State, and local regulations. The undersigned is familiar with the soils, vegetation, and hydrologic characteristics of this property from previous investigations of adjacent properties in the immediate vicinity and throughout the drainage basin. 3.0: Description of the Action and Project Areas Spokane is located in a valley at the westmost extent of the Rocky Mountains. From the north side of the Spokane River valley, the Selkirk Mountains extend north into Canada. On the south side of the Spokane River valley, a forested finger of the Bitterroot Mountains extends east from Lake Coeur d'Alene to Dishman Hills. The subject property is located in the Chester Creek valley with forested foothills on the east and west sides of the valley. The Painted Hills PRD is surrounded primarily by residential development with varying degrees of housing density, a few small undeveloped tracts of agriCUltural land in the Chester Creek valley, and forested land with varying densities of residential development (Figure 4). 3.1: Description of the Action Area For purposes of describing habitat in the surrounding area, the Action Area is defined as a half mile radius of the project area. Habitat types in the Action Area would be described as a mosaic of urban developed, fragments of conifer forest, and small tract agriculture. From the north property line, dense residential development extends north into the City. A church and residential development border the painted Hills PRD at the NW comer. Horizon Middle School is located NE of the site. From the east property line (S. Madison Rd) hay fields and pasture extend 250-500 feet toward the toe of the surrounding forested slopes. Sparse residential extends east up the forested hillsides. Commercial and single family residential development extends south from Thorpe Road except for the Chester Creek drainage and associated flood plain that is mainly forested and small tract agriculture. Undeveloped forested hillsides extend about 1200 feet east to the densely developed Ponderosa neighborhood. A mixture of commercial and residential land uses extend NW along Dishman-Mica Road. 5 3 7\ = 3 m J w U1 I -' -, Land uses in the Action Area are a mosaic of dense residential development on former agricultural land, remaining undeveloped small tracts of agricultural land, and forested land with varying densities of residential development. Large mammals that are willing to cross highways and residential developments interspersed with open farm land will find connectivity to a few hundred acres of wooded and sparsely populated foothills extending south and west from the Painted Hills PRD site to Dishman Hills. 3.2: Description of the Project Area The 93+ acre Painted Hills PRD property was formerly a golf course. Black Realty Inc. bought the property in a trustees auction in the fall of 2013 after the owners filed for bankruptcy in 2012. Except for cart paths, sand traps, and man-made water hazards, the entire property was planted in non-native turf grasses with sparse conifer and deciduous trees lining some of the fairways. The turf grass was maintained by treatment with herbicides and regular mowing of the greens, fairways and rough. These practices virtually eliminated the native herbaceous plant community. Honey willows were planted inside the OHWM of Chester Creek whose channel was historically dredged and maintained for flood control. The banks of the channel are covered with Reed canarygrass. Outside the OHWM of the stream channel where the vegetation was not mowed or maintained, the vegetative community is dominated with Canarygrass. Teasel, tansy, thistle, wormwood, and lettuce are also well represented. 4.0: Project Risk Assessment and Impacts Listed threatened and endangered species identified by jurisdictions for potential occurrence in Spokane County include the Yellow-billed Cuckoo (Coccyzus american us), Canada Lynx (Lynx canadensis), Bull trout (Salvelinus confiuentus), Water howellia (Howellia aquatilis) and Spalding's silene (Silene spaZdingii). A BSW field investigation determined that the project would have NO EFFECT on any of the above listed species. 4.1: Yellow-billed Cuckoo (Coccyzus american us), Federal Status: Threatened The yellow-billed cuckoo was formerly a very rare summer visitor to western Washington, especially in the Puget Sound area (Roberson 1980). Jewitt et al. (1953) described the former breeding range in Washington as ranging north to Bellingham, east to Ellensburg, south to Vancouver, and west to Grays Harbor. There are only two published records of yellow- billed cuckoo in eastern Washington. Yellowbilled cuckoos were detected on July 21, 1956,20 miles north of Grand Coulee Dam in Okanogan County (Weber and Larrison 1977) and in June 1978 at George, Grant County (Roberson 1980). The March and April investigations occurred before the Yellow-billed cuckoo would have migrated into the Spokane County area if it seasonally utilized the area for breeding or nesting. The investigation for the Yellow-billed cuckoo focused on specific habitat requirements of that species. Cuckoos prefer to nest in areas with at least 10 hectares (ha) (25 acres) of contiguous (riparian) woodland (Laymon 1998). The typical patch size is 20 ha (50 acres) or greater, and the likelihood of occupancy increases dramatically with increasing patch size, but they have been found breeding in patch sizes as small as 4 ha (l0 acres) along the Colorado River in southern California (Johnson, Matthew J., 2007). Yellow-billed cuckoo's nest in undisturbed stands of cottonwood/willow galleries greater than 10 acres in total area and greater than 100 meters wide along waterways. 7 J The project area does not contain, and is not in close proximity to, adequate habitat patches for that species. The largest habitat patch consisting of species utilized by the yellow- billed cuckoo is less than one tenth of the minimum patch size utilized by this reclusive species. The yellow-billed cuckoo is known not to utilize any habitat with characteristics of those found along Chester Creek adjacent to this project. This project will not impact yellow-billed cuckoo populations or habitat components. There is no suitable habitat for the yellow billed cuckoo in the vicinity of this project. 4.2: Bull Trout (Salvelinus confluentus) Threatened The U.S. Fish and Wildlife Service (USF&WS) lists the Columbia River population of bull trout as threatened. Small pockets of bull trout are present in isolated habitat fragments in the main stem and tributaries of the Columbia River. One isolated fragment of the Columbia River segment includes Coeur d'Alene Lake, its tributaries in the drainage basin, and the Spokane River. Bull trout populations have been identified in Coeur d'Alene Lake and three tributaries in its sub-basin, but no bull trout populations are known to occur presently, or have been noted historically, in the Spokane River downstream from the Post Falls Hydroelectric Dam (PBTIAT, 1998). The Post Falls dam stops the migration of fish out of the Coeur d'Alene basin downstream into the Spokane River. Waterfalls and dams prevents the upstream and downstream migration of bull trout into the segment of the Spokane River and its tributaries in the vicinity of the project area. No dam on the Spokane River has a fish passage facility and all dams create fish barriers for upstream and downstream migration. EPA fact sheets for 1999 NPDES permits for wastewater treatment plants discharging to the Spokane River state that bull trout cannot get past the Post Falls Dam (EPA 2008). There is no known population of bull trout in the Spokane River downstream of the Post Falls dam (pERC 2006). The USFWS does not include the Spokane River and its tributaries located downstream from the Post Falls dam in bull trout recovery planning efforts (Federal Register / Vol. 75, No. 200 / Monday, October 18, 2010). The project will have No Effect on Bull Trout. Bull Trout Critical Habitat Activities that may adversely modify critical habitat include those that alter the primary constituent elements to an extent that the value of critical habitat for both the survival and recovery of the bull trout is appreciably reduced. The proposed project will not destroy or adversely modify critical habitat by altering primary constituent elements. The value of critical habitat for both the survival and recovery of the bull trout will not be reduced as a result of this project. The project will not alter the minimum flow or natural flow regime of the subject stream, alter any segment of the stream, riparian vegetation, or any chemical parameters so as to reduce water quality, alter channel morphology or create instream barriers to bull trout movement. No decrease in water quantity will occur because of the project. The project will cause no significant and detrimental alterations to water quality and will have NO EFFECT on proposed Bull Trout Critical Habitat. 4.3: Spalding's catchfly (Silene spaldingil), Federal Status: Threatened The range of Spalding's silene (Silene spa/dingii) includes eastern Washington, northeast Oregon, Idaho, and western Montana. Spalding's silene occurs primarily in open grasslands with minor shrub and/or (occasionally) scattered conifer components. Spalding's silene is found most 8 I I . ..J J commonly in Idaho fescue/snowberry associations at elevations of 1900-3050 feet. These sites are typically dominated by Idaho fescue and have sparse cover of snowberry where the total vegetative cover is greater than 100%. Some of these sites occur in a mosaic of grassland and ponderosa pine forest. Spalding's silene populations have been found on all aspects, although there seems to be a preference for slopes that face north. On drier sites, the species can be found on the bluebunch wheatgrasslIdaho fescue association. Spalding's silene can occupy habitats that vary from sagebrush plains to mountain ridges. Spalding's silene generally occurs in native grasslands that are in reasonably good ecological condition, although populations have persisted in areas that have had moderate grazing pressure. Populations tend to be quite small and are currently quite fragmented, raising questions about their long-term viability. Fire may have historically played a role in maintaining habitat particularly in sites that are interspersed with ponderosa pine forest. Much of the historically suitable habitat has been lost through conversion or degradation. The timing of the site investigation did not coincide with the flowering of listed plant species. The project biologist is a qualified botanist and wetland professional that routinely completes site investigations during all seasons when snow does not cover vegetation. Site investigations often occur when salient plant flowering parts are senescent or may not be sufficiently preserved to allow taxonomic identification beyond genus to the species level. Twenty years of experience in plant identification during all life history and seasonal growth habits has equipped the project biologist to conduct accurate plant identifications and wetland investigations in accordance with best available science and consistent with the accepted professional practices for the conditions at the time the work was performed. Individual plants exhibit essential identification characteristics unique to their genera, but display sufficient variation so it is possible to categorize and differentiate each species within a genus using taxonomic keys. During plant senescence, individual characteristics often become blurred making it difficult or impossible for a botanist to differentiate among species within the genus. The sepals of the genus Silene form a bulbous calyx that is easily recognized and sufficient to identify the plant to genus. The Threatened species Silene spaZdingii overlaps in range and is somewhat similar in appearance with some other species in the genus. The field biologist is familiar with the species and has observed it at other locations. During the field investigation, the Silene genus was not identified in the Action or Project Areas. Previous years of cultivation, followed by the planting of turf grasses, years of mowing, and herbicide applications is sufficient grounds for discounting effects on Spalding's silene when considered alone. No populations of Spalding's silene were identified in the Project Area during the field investigation. The project will have NO EFFECT on Spalding's Silene and will not result in the destruction or adverse modification of potential, designated or proposed Spalding's silene Critical Habitat. 4.4: Water howellia (Howellia aquatilis) Howellia is found in seasonal wetlands, ponds and lakes because its seeds do not germinate under water. Since seeds germinate in the fall and over-winter as seedlings Howellia requires a dry autumn followed by a wet spring in order to establish for the year. In addition to seasonally fluctuating ponds, Howellia requires fertile, highly organic soils, which are generally maintained by deciduous trees surrounding the ponds. Research indicates that Howellia does not form a persistent seed bank, making this annual especially dependent on year to year reproductive success in order to persist. 9 I' I I' , I --, I 1 __ I No Howellia was observed in the Project Area. Howellia is found in seasonal wetlands, ponds and lakes. No Howellia habitat occurs in the Project Area. The project will have NO EFFECT on the Howellia aquatilis species and will not result in the destruction or adverse modification of potential, designated or proposed Howellia Critical Habitat. 4.5: Canada lynx (Lynx canadensis) Federal Status: Threatened Lynx prefer dense coniferous forest with sapling/pole thickets, rock outcrops, and wetlands at elevations of around 4000' to 4500'. The elevation of the Action Area is around 2010-2015 feet. Denning usually occurs in mature old growth stands with lots of deadfall. These forested stands do not occur in the Action Area. Lynx prefer snowshoe hare habitat, as they are dependent on snowshoe hare as a staple food item. Snowshoe hare prefers dense lodgepole stands that do not occur in the Project or Action Areas. BSW did not fmd any evidence of Canada lynx in the low elevations associated with the Project Area. The project will have NO EFFECT on the Canada lynx or Canada lynx habitat. 4.6: Species of Concern The site was also investigated for the presence of species from the Species of Concern list for Spokane County published by the U.S. Fish and Wildlife Service. Most of these species are also included in the WDF&W list of priority species that was adopted by the City of Spokane Valley. Each species is listed below, followed by an evaluation of available habitat, observed habitat utilization, and potential project effects. Bald eagle (Haliaeetus leucocephalus) The Bald eagle is listed as a State Sensitive species. Eagles do not nest near the Project Area. Human activity associated with major roads and urban development are limiting factors for Bald eagles in the Action Area. At any location in Spokane County road kill can provide food for transient opportunist eagles. However, Bald eagles do not routinely forage in the Action Area and no nest sites were observed by BSW within one-half mile of the Project Area. BSW concludes that noise and human activity during construction will not' impact eagle nesting as no nests were identified in the Action Area. Perching and foraging opportunities occur on the stream bank and eagles could utilize the stream corridor. The project will have NO EFFECT on the Bald eagle. Western Burrowing Owl (Athene cunicularia) No historical observation in the vicinity. No individuals, nests, or sign observed during the site survey. No Effect from project. California floater (Anodonta californiensis) freshwater mussel. No Effect from project. Ferruginous hawk (Buteo regalis) nests on rocky ledge or high ground vantage on prairie. No Effect from project. Giant Columbia spire snail (Fluminicola columbiana) cold, unpolluted, medium to large streams. No Effect from project. Loggerhead shrike (Lanius ludovicianus) A robin sized gray, black, and white bird of open areas. Community types not dominated by shrubs, such as grasslands and riparian areas, are not used. Loggerhead Shrikes prefer nesting in big sagebrush and antelope bitterbrush, and avoid spiny hopsage, rabbitbrush, and green rabbitbrush (Chrysothamnus viscidiflorus). Nest shrubs are taller, closer to an edge, and contain denser cover and fewer main stems than unoccupied shrubs. Roost shrubs are large, dense live shrubs, whereas tall, dead shrubs that provide good visibility are used for perching. No Effect from project. 10 • j 11 I Longeared myotis (Myotis evotis) Roosts are sometimes found in crevices in small basalt rock formations. Compared to random plots, roosts are in more open, rocky habitats, closer to edge of forest stands, and relatively distant from sources of permanent water. Often roost in Ponderosa pine trees >30 cm in diameter and >12 m high. Less use of grasslands and closed pine than expected. No significant effect if present in vicinity. Northern goshawk (Accipiter genti/is) goshawks select relatively closed-canopy conifferouslboreal forest habitat for nesting -No significant effect. Olivesided flycatcher (Contopus cooperi) found in boreal and western coniferous forests -No Effect Pallid Townsend's bigeared bat (Corynorhinus townsendii pallescens) Eastside mixed conifer forest, shrub-steppe, and riparian-wetlands. In Washington, old buildings, silos, concrete bunkers, barns, caves, and mines are common roost structures. No effect on roosting or hibernicula Peregrine falcon (Falco peregrinus) Two subspecies of peregrine falcons (Falco peregrinus) occur in Washington state at present, (F. p. pealei and F. p. anatum). Peale's peregrine falcon is a coastal subspecies so our concern in Spokane County is with F. p. anatum (Continental peregrine falcon). DDT exposure totally eliminated this subspecies from former breeding sites in eastern Washington. Following a ban on the use of DDT, captive-reared young birds have been released at several sites in Spokane County in an attempt to augment natural reintroductions by wild birds. There is no potential for degradation or loss of critical habitat for peregrine falcons in the project area. Peregrine falcons nest on cliffs or even man-made structures such as buildings or bridges that do not occur in the project area so no action is required to protect nest sites from human disturbance. The primary method used to reintroduce falcons to the wild is called "hacking". WDF&W does not currently use any hack sites in the vicinity. No significant effect Redband trout (Oncorhynchus mykiss) No Effect from project. Sagebrush lizard (Sceloporus graciosus) No Effect from project. Westslope cutthroat trout (Oncorhynchus clarki lewisi) No Effect from project. Palouse goldenweed (Haplopappus liatriformis) palouse, not in our area No Effect 4.7: WDF&W Priority Species Deer, Elk, and Gray Wolf Impacts to the WDF&W Priority Species White-tailed deer and Elk will be minimized by protecting a travel corridor through the site. The subject property is not mapped as White-tailed deer priority habitat. Wooded lands to the east and south are mapped as priority white-tailed deer habitat. However, deer utilize the site as they do all undeveloped parcels in the area. The site falls within the northern extent of the mapped Elk Habitat polygon in the Spokane Valley. The site does not provide cover or refugia required by elk and is not elk habitat, but Elk moving through the general area between Mica Peak and Dishman Hills could potentially cross the subject property on east/west treks. The developer will protect and enhance an east/west 8+ acre deer and elk travel corridor across the property. Woody vegetative plantings prescribed for the corridor will provide some habitat value and protective cover where none currently exists. Deer will continue to use the area set aside as a travel corridor. The site is also mapped as Gray wolf habitat. It is possible that wolves could travel through the area in search of prey. There are deer and abundant small (domesticated) mammals available in this residential area so their presence would not be well received in the surrounding neighborhoods. Wolves could also utilize the 8+ acre travel corridor for safe east/west passage through the property. 11 4.8: Wetlands Wetland Inventory Maps of the site show two wetlands on the property (Appendix 2). Both of the wetlands are shown to occur on the west side of Chester Creek. BSW investigated the mapped wetlands on March 1, 2015 and in each mapped wetland, dug a test hole on top of the creek bank in close proximity to the Chester Creek OHWM. On March 1, neither of the test holes had saturated soils in the top 16 inches of the soil profile. In Test Hole #1 the water table was at 21 inches and saturation occurred at 16 inches. In Test Hole 2, there was no saturation in the top 24 inches of the soil profile. The test holes were inspected again on March 29th and the water level in test holes was lower than on March 1 st. This result was expected due to the landscape position of the mapped wetlands. The year to date precipitation for Spokane was hovering slightly above normal for the year to slightly below normal for the year to date so wetland hydrology should have been present in what was a normal year at the time of the investigation if the subject areas were wetlands. The argument that Spokane was below normal for the hydrologic year is not valid for this drainage basin because it has a low elevation and runoff comes earlier in the year than many other drainages as will be explained in detail below. The wetland hydrologic criteria was not met in either test hole at the start of the growing season when the water table should have been at its annual high. Stream high water conditions consistent with a high water table does not typically occur during the growing season on Chester Creek. Seasonal high water occurs in the winter during rain on snow and frozen ground conditions. During the growing season, wetland conditions do not occur outside of the stream OHWM where the National Wetland Inventory Map indicates the wetlands occur. David Moore, DOE, investigated the site on June 8, 2016 and concurred with that fmding. 4.8.1: Chester Creek Flood Frequency A hydrologic and hydraulic analysis for Chester Creek was completed by Michael Baker Jr., Inc. and approved by Spokane County in a letter to the Federal Emergency Management Agency dated August 6, 1990. There are no long-term gage records for Chester Creek. The limited gage measurements on Chester Creek were collected near the Dishman-Mica Road crossing of Chester Creek from December 1994 through March 1995 and November 1995 through February 1996 when no flood events occurred. In February 2006, the hydraulic analysis for Chester Creek was revised by West Consultants, Inc. under a FEMA contract. The analysis established flood magnitude-frequency estimates for the watercourse. A steady flow model has been developed for Chester Creek. The reports conclude that spring floods in the upper Spokane River basin are due to snowmelt runoff from high elevation watersheds. Such floods are of less significance on Chester Creek because the lower elevation of the watershed limits the size of the snowpack so spring runoff occurs about a month earlier and at more gradual rates than on the Spokane River. Nearly all maximum annual flood peaks on Chester Creek occur during the winter. Warm winds and rain can melt the snow rapidly. The May 1948 flood on Hangman Creek was a non-typical flood caused by a heavy snowpack, a late, cold spring, and heavy rains during the critical snow melting period. All other maximum annual flood peaks on Hangman Creek occurred during the winter. When winter rain causes snowmelt on frozen soil conditions, short-duration, intense runoff generates a flood peak during winter storms. During the more extreme events, Chester Creek runs over its banks filling depressions in the flood zone. The duration of flooding is generally between 100 hours and 1000 hours, or between four days and forty days with smaller events occurring with greater frequency than large events. 12 Hydric soils form under saturated soil conditions. Wetlands have to exhibit saturated soils during the growing season, but those conditions seldom occur outside of the stream channel on Chester Creek because flooding usually happens in the winter. Floods are typically of a small magnitude so when over bank flow fills depressions outside of the channel, the water has usually infiltrated before the growing season begins. The subject areas may have been exposed to more frequent flooding in the past, but good planning and flood control measures designed to minimize flooding have moderated those historical flood events to some degree. Chester Creek does not follow the same hydro graph as snowmelt dominated systems. 4.8.2: Flood Protection Measures Channel geometry for Chester Creek were developed from surveys conducted in March 2003. Overbank geometry were developed from topography developed by TerraPoint (2003). Flood plain boundaries for Chester Creek and Unnamed Tributary to Chester Creek were delineated using 2 foot contour interval maps developed by TerraPoint from LiDAR data. Previously, a watershed plan for Chester Creek was designed with management recommendations for drainage, flooding, water quality, and riparian habitat. As a result, flood control improvements have been implemented along Chester Creek. The improvement area began at the Painted Hills Golf Course. In 1998, a project to install new culverts and extensive dredging of the channel between Thorpe Road and Schaffer Road was implemented. Two large volume borrow pits were constructed downstream. Each pit was designed for the retention and infiltration of Chester Creek floodwaters up to a 25 year event. One borrow pit was constructed just north ofE. 40th Avenue and the other just south of 28th Avenue. The Chester Creek channel has been historically maintained as has been reported in the literature and supported by direct evidence of spoil piles on the channel banks. Dredging makes the channel deeper and the dredging spoil piles make the channel banks higher. As a result of channel dredging, the surrounding areas are dewatered faster and the water table falls a corresponding distance deeper below the soil surface. Soils in the areas mapped as wetland exhibit some relic hydric characteristics from infrequent historical flooding, but with the exception of rare flood events, the water table is too far below the soil surface at the start of the growing season to meet the wetland hydrologic criteria. The two mapped wetlands do not meet the hydrologic criteria so they are not wetlands. They are low lying areas adjacent to Chester Creek that have been historically flooded, but flooding is far too infrequent for the subject areas to meet the wetland hydrologic criteria. Even if they were wetlands, they are on the opposite side of the creek from where development is proposed so the riparian buffer would be more restrictive and extend further east into the development than a wetland buffer. The undersigned filled out the current Wetland Rating Form and determined that if the mapped wetlands were actually wetlands, they would be Category 2 with a total point score of 19 points. The City Code assigns buffer widths based on points scored on the previous rating form. Using the previous rating form, the wetland scores 18 points for habitat functions so the buffer width would be 100 feet. The 100-foot buffer applied from the "(non)wetlands" located on the west side of the creek would only extend about 70 feet east of the creek so the 100-foot riparian buffer would be more restrictive to development and extend further east, even if wetlands did occur on the site as mapped. There are no wetlands on the subject property. Additional flood control measures are being incorporated into the project design (see the Painted Hills Flood Control Plan). In the original version of this report, shallow ponds and 13 l subsurface gravel galleries were proposed at the south end of the property in the proposed wildlife travel corridor. The stormwater plan was subsequently revised to eliminate the ponds and gravel galleries. A three foot box will be installed in the Right of Way to prevent back up on the Haase property south of Thorpe. On the north side of Thorpe, water will proceed east in a concrete channel to Madison Road where it will be piped north to an infiltration field at the north end of the development. This plan revision will eliminate potential wetland impacts on the south side of Thorpe. Other flood control measures will be required by FEMA as part of the levee certification process. To my knowledge, the channel was last dredged and maintained in 1998. Since that time honey willows planted in the Chester Creek channel have grown quite large. Roots of the honey willow compromise the integrity of the levee and their removal is required by FEMA as part of the levee certification process. Those riparian zone impacts cannot be mitigated in the stream channel or on the stream banks so the mitigation (replacement plantings) will occur in the riparian buffer and in the wildlife travel corridor. Replacement plantings of trees and shrubs will be installed as detailed later in this report. 4.9: Riparian Areas The DNR Water Type Map (Figure 5) defines Chester Creek as a Type F Water. Chapter 21.40 of the City of Spokane Valley Municipal Code, titled Critical Areas, bases stream buffer widths on the DNR Riparian Management Zones. Chester Creek is greater than 15 feet in width (bankfull) so the appropriate buffer width can be found in Table 21.40-10 of the City Code. The DNR guidance states that in Eastern Washington, if there is no site index information, as in this case, assume Site Class III unless site specific information indicates otherwise. The table indicates that a Type F Natural Water not classified as a Shoreline of the State, having a Site Class 3 designation, has a total buffer width of 100 feet. BSW delineated the Chester Creek OHWM in the field on March 31, 2015. The OHWM flags were surveyed and plotted on the site plan map along with the I ~O-foot riparian buffer by Whipple Consulting Engineers. The DNR Water Type Map also identified a Type F Water located about one mile east of the subject property. The map showed the stream crossing SR27 and running NW across a cultivated field before disappearing. There is no stream in that location so a Water Type Modification Form was submitted to Spokane County. The form was circulated to all appropriate agencies, the Water Type change was approved, and that stream segment was removed from the map. However, the FEMA map shows potential flood waters traveling toward the proposed development from that general direction. So additional work is being required by FEMA to raise the levee of an unregulated, man-made ditch located on adjacent property to the north. Several years ago, the ditch was proposed, approved, and created to convey stormwater to a borrow pit. After the levee improvements now required by FEMA, floodwater will have the same fate as stormwater and be conveyed into the borrow pit where it will infiltrate and have no impact on the proposed development. No impacts are proposed to regulated waters by this FEMA requirement so no mitigation is required. 5.0: Riparian Buffer Impacts, Buffer Averaging, and Impact Mitigation Chester Creek and its associated 100-foot buffer bisects the SW corner of the property. Buffer Width Averaging and buffer enhancement are proposed as mitigation for proposed riparian buffer impacts. The existing buffer is almost totally devoid of woody vegetation because the site was previously utilized and maintained as a golf course and driving range. 14 J J Map Output TOWNSHIP 0 NORTH HALF undefined, RANGE 0 (W.M.) HALF undefined, SECTION 0 1I Application #:. ___________ _ 28454 2 + 2B40 . : + U \-• 4/1/20159:23:14 AM NAD83 Contour Interval: 40 Feet Page 1 of 1 http://fortress. wa.gov/servleticom.esri.esrimap.Esrimap?ServiceN ame=fpars&ClientVersjon... 4/1/2015 · J l ...J J 1 .J Buffer impacts are proposed in six areas (Figure 6) with a total buffer impact of 23,877 sq. ft. (0.55 acres). The impacts will be mitigated in several ways. Buffer Averaging will be employed to insure no net loss of buffer occurs. The existing buffer will be enhanced by the planting of tree and shrub patches. The buffer replacement area will be enhanced by the planting of tree and shrub patches. The proposed 8+ acre wildlife habitat/travel corridor will be enhanced by the planting of tree and shrub patches. 5.1: Buffer Impacts from Two Homes Part of the buffer impact (8725.60 ft2) results from two lots located in close proximity to the southmost bridge across Chester Creek. The subject area experienced the highest intensity human activity on the property during the years of golf course operation. Foot and golf cart traffic from the club house was directed by cart paths over two bridges to the fairways, driving range, and practice areas across the creek where the buffer impact from two lots is proposed. The only remaining woody vegetation is located inside the Chester Creek channel where honey willows were planted in the channel thirty years ago. FEMA requires all woody vegetation and roots to be removed within 15 feet of the levee so no woody vegetation will remain in the subject area. The removal of woody vegetation and continued use of the two bridges and trails crossing the stream and buffer has the effect of funneling, controlling, and limiting human access to this narrow corridor or choke point. The existing bridges will be utilized and the cart paths will be extended east to connect the housing development on the east side of the creek to the bar and restaurant located in the former golf course clubhouse on the west side of the creek. This part of the riparian buffer will continue to experience high intensity human activity. This part of the buffer historically experienced the highest degree of degradation and will continue to experience the greatest intensity of human activity. The proposed impacts occur in an existing disturbed area that will benefit the least from protection, while the mitigation is proposed where it will have the greatest benefit for wildlife. The Critical Areas Ordinance states that buffer areas may be modified by the director if "the riparian area contains variations in sensitivity due to existing physical characteristics which justify the averaging." The variation in habitat physical characteristics and sensitivity in the riparian buffer are a result historical land uses and variation in the intensity of human activity. The area around the two bridges will benefit least from protection or habitat enhancement due to historical and continued high intensity human activity in this existing disturbed footprint. Some vegetative plantings will be installed between the proposed buffer encroachment and the creek, but there will be little wildlife activity in this area. Woody vegetation plantings will function mainly as human esthetic improvements but will have some benefit for birds. The vast majority of the vegetative plantings prescribed as mitigation for the buffer reduction will be installed in patches throughout the rest of the buffer where there will be little human activity and the vegetative enhancements will provide greater function for wildlife habitat. In the proposed buffer replacement area there is currently little woody vegetation so native trees and shrubs will be planted densely to improve habitat quality. Habitat enhancement will also occur in the designated wildlife travel corridor and where wildlife will benefit the most from the enhancement. 16 I J 11 ! J 'I I .J Variations in sensitivity are created by the existing physical characteristics (bridges and trails), historical land uses (vegetation removal and intense human activity), and the continued concentration of human activity on trails and bridges through that narrow corridor across the stream and buffer on both sides. That corridor has the least habitat function because it has the least wildlife activity. The proposed buffer impact will occur in the least sensitive area from the perspective of wildlife presence, use, and function. Buffer enhancement will occur where there is the least human activity and the greatest benefit for wildlife from the perspective of wildlife presence, use, and function. The total area contained within the buffer after averaging is greater than that contained within the standard buffer prior to averaging. 5.2: Buffer Impacts from the Trails and Road Improvement Three separate buffer impacts will occur from trails. Two of the impacts will result when the existing trails are extended from the bridges into the development and connected to a proposed trail in the 8+ acre wildlife travel corridor. A third impact will occur when an existing parking lot at the south end of the property is connected to the trail system. The three buffer impacts result in an additional 4356.09 sq. ft. of riparian buffer impact. The buffer impact areas will be replaced in the remediation area shown in Figure 6. The required improvement of Thorpe Road will result in an additional 2,752 sq. ft. of buffer impact. Those impacts are listed under the heading of Right-of-Way impacts on Figure 6. The total riparian buffer impact area of 23876.38 sq. ft. will be replaced with 24,136.34 sq. ft. of new buffer. The proposed 8+ acre Wildlife Travel Corridor is basically an extension of the buffer replacement area and will also be enhanced with vegetative plantings (Figure 7). 5.3: Mitigation of Willow Removal from the Chester Creek Levee As previously stated in Section 4.8.2 of this report (titled Flood Protection Measures) the creek banks in the project area are defined as a levee and are subject to a certification process. The channel may not have been dredged or maintained since 1998. Since that time, willows have grown taller in the Chester Creek channel. Willow roots compromise the integrity of the levee and their removal is required by FEMA as part of the levee certification process. The impacts associated with willow removal will be temporary. The equipment will operate when the channel is dry so water quality impacts are not an issue. Best Management Practices and spill control protocols will be strictly adhered to and peripheral impacts will be held to a minimum. The channel may be dry, but the equipment operators must respect the sensitivity of the area, install construction fences to identify minimized work areas, and take all prudent measures to minimize impact in the buffer. All temporary impact areas will be restored at the earliest possible moment to prevent soil erosion. The replacement woody vegetation plantings cannot be placed in the stream channel or within 15 feet of the levee so the replacement planting will occur in the riparian buffer and wildlife travel corridor as detailed later in this report. 5.4: Temporary Buffer Impact Mitigation Since the original HMP was submitted in 2015, it was determined that the height of the levee must be increased in two places. The purpose of raising the levee is to provide an additional one foot of freeboard at existing crossings. Starting at, and extending 100 feet north from Thorpe Road, the levee height will be raised one foot on the east side of the creek. The levee will also be raised one foot in height on the east side of the creek between and around the 18 l I l two foot bridges. This work will be completed in strict accordance with the Best Management Practices and comply with FEMA specifications. All areas with exposed soils on the new levee and peripheral disturbed soils will be planted with a native seed mix as specified by FEMA to prevent erosion and facilitate future levee inspection. 5.5: Buffer Impacts in the Two Commercial Triangles One small area of buffer impact could occur where Chester Creek exits the property and flows under Dishman-Mica Road (Figures 6 & 7). The riparian buffer extends slightly into an 1134.16 sq. ft. triangle of a commercially zoned lot. The triangle may never be impacted, but if the adjacent commercial area is developed, the adjacent land use will effectively destroy the buffer function. BSW is identifying that as an impact and relocating the small triangle of buffer to the proposed buffer averaging replacement and enhancement area that will provide greater benefit than leaving it in place in its current condition along the road where it has no habitat value. The same is true for a commercially zoned 5921.97 sq. ft. triangle of buffer located east of the restaurant parking lot (west side of the creek). An existing building in that general area may be tom down so the existing parking lot could be expanded at some future date. The subject triangle was historically mowed adjacent to the parking lot and provided no habitat function. The vegetative community is dominated by canarygrass with lettuce, tansy, knapweed, and wormwood also represented. The commercially' zoned triangle may never be impacted, but if the adjacent area is developed, that land use will effectively destroy the buffer function. BSW is identifying it as an impact and relocating the buffer to the proposed buffer replacement and enhancement area that would provide greater benefit than leaving it in its current condition where it has no habitat value. The area between the potential future impact and the stream will be enhanced as part of the mitigation plan. The buffer will be smaller in that area, but the resulting mitigation and vegetative enhancement will represent an improvement over the existing condition and justifies moving it instead of leaving it at the present location. 5.6: Mitigation Area Summary The proposed buffer mitigation provides very generous compensation for the proposed impacts. Buffer impacts are proposed in six areas with a total buffer impact of 23,877 sq. ft. (0.55 acres). The impacts will be mitigated in several ways. Buffer Averaging will be employed to insure no net loss of buffer occurs. The 23,877 sq. ft. impact area will be replaced with a 24,137 sq. ft. area that is contiguous with the existing riparian buffer. The area of proposed buffer reduction will be enhanced by the planting of tree and shrub patches. The remaining riparian buffer will also be enhanced by planting patches of native woody vegetation on both sides of the stream. The buffer replacement area will be enhanced by planting native tree and shrub patches. The buffer replacement area will be contiguous with the 8+ acre Wildlife Travel Corridor where additional tree and shrub plantings are proposed to mitigate the approximate 200 lineal feet of temporary impacts to the levee. All proposed temporary impact areas will also be restored with native vegetation as prescribed by FEMA (COE guidelines). The proposed vegetative enhancement of the remaining buffer areas, replacement buffer areas, and wildlife travel corridor provides generous mitigation to offset the impacts. The proposed vegetative enhancement represents a significant improvement compared to the existing condition and historical land uses of the last several decades, so buffer averaging results in the necessary biological, chemical, and physical support necessary to protect fish and wildlife. 20 l 1 l ., J J Monitoring of the vegetative plantings will continue for 5 years or until the City of Spokane Valley is satisfied that the conditions of the mitigation plan have been met. Reinforcement plantings and weed control will be prescribed by the project biologist as determined by annual site monitoring. The minimum container size shall be one half gallon. Vegetation shall be planted at the landscapers discretion according to conditions on the ground and the location of existing vegetation. Plantings shall be interspersed around existing vegetation, and where possible, in patches of 15-25 plants of mixed size and species as indicated in the plan. 5.7: Noxious weed control The dominant invasive species that were identified on the site include tumble mustard and knapweed. These species are known for their ability to propagate and spread rapidly with catastrophic impacts on native species. As required by Washington State Noxious Weed Control law, RCW 17.10, and the Spokane County Noxious Weed Board, invasive species will be managed through control measures that do not adversely impact native vegetation. Funds will be allocated for noxious weed monitoring and herbicide control as part of the proposed mitigation for this project. Black Realty shall contract their preferred weed control specialist to monitor the site and provide weed control in the enhancement area at the appropriate intervals throughout the growing season to prevent seed set. 5.8: Revegetation with Woody Plants In addition to noxious weed control, mitigation for buffer impacts will include the planting of native trees and shrubs. The buffer will be re-vegetated with native plants including species from the tree, shrub, and grass vegetative strata. The replication of natural spatial relationships, structural complexity, vertical stratification, and microhabitat diversity will be stressed in the planting design to achieve a mosaic of open areas and dense tree/shrub clusters. Vegetation will not be planted in a uniform manner. Shrubs will be planted in grouped patches and interspersed with other shrub species and height classes. Patch size will be variable with curving edges. The incorporation of these elements will increase landscape diversity and promote habitat elements that are often scarce or absent at sites that have been disturbed. Native species and endemic plant materials will be selected for site revegetation to help maintain ecotypes that are adapted to local climatic and soil conditions and preserve local genotypes. 5.9: Objectives for the Restored Riparian Buffer Restoration will be achieved by planting native trees, shrubs and grasses primarily to provide food and cover for wildlife. The Vegetation Plan will incorporate as many design features as possible for each function in order to increase the value for that function. Objective a: Re-establish species diversity and structural diversity in the buffer by replanting native tree and shrub species from each vegetative class. Objective b: Re-establish vegetative species and structural diversity to re-establish bird and mammal habitat values in the enhanced buffer areas. Objective c: Re-establish vegetative density in the riparian buffer area. 21 l l l , J J J J 5.10 Planting Strategy Woody plant materials will be installed at the industry standard density of 360 stems per acre. The buffer replacement area is 0.55 acres X 360 stems/acre = about 200 containers. The Buffer Replacement Area shall have 200 containers planted within that polygon. An additional 200 containers will be distributed throughout the east and west sides of the creek in the existing buffer and buffer reduction areas (Zone 1 and Zone 2, Figure 8). An additional 400 containers shall be planted in patches of 20 containers throughout the designated wildlife travel corridor. The replication of structural complexity, vertical stratification, and microhabitat diversity will be emphasized in the planting design. Shrubs will be planted in the buffer with the goal of providing wildlife habitat and enhancing the functions and values of the buffer. The vegetation will be planted in patches, have curving edges, and will not be planted in a uniform manner. 5.11: Rationale Structural complexity refers to the arrangement and degree of interspersion of plant community types throughout the system. Complex structural patterns (such as variable patch size, curving edges, and high degree of interspersion between species) increase the value of a system for wildlife. Good wildlife habitat consists of open areas interspersed with clusters of vegetation, several horizontal layers, and a variable structural pattern. Vertical stratification describes a community with good structural diversity and several horizontal layers (logs, woody debris, forbs, shrubs, and trees). Woody debris provides travel routes, perch sites, cover, and thermal refuge for a variety of small mammals and ground nesting birds. Microhabitat diversity refers to variety in microhabitat types. Examples of microhabitat types include herbaceous cover and shrubs that provide food, habitat, and substrate for a variety of animals. 6.0: Mitigation Planting Plan 6.1: Materials Specification Clusters of vegetation will be planted according to the guidelines prescribed above. The specified number of containers will be planted within each zone as shown in Figure 8. Zones 1 and 2: Riparian Buffer on East and West Sides of Chester Creek A total of 200 containers planted in existing buffer areas Common Name Scientific Name # Planted Trees Ponderosa pine Pinus ponderosa 20 Large shrubs serviceberry Amelanchier alnifoloia 40 mock orange Philadelphus lewisii 40 Small shrubs Wood's rose Rosa woodsii 30 common snowberry Symphoricarpos albus 50 Phlox sp. Phlox speciosa or longifolia 20 Total 200 22 l l l ~ _, - 1 J c:-.., 1------1------ O;~ ST1E R~C R_~.E r-~ ~ 0 N I I I I 1 SE , SEC.33, T.25N., R.44E" W.M. SW2, SEC.34, T.25N., R.44E., W,M . NEt, SEC. 4, T .24N., R.44E., W.M. INEATION, . . '" ~ g . " ~ . . I ! .1 IIH~----~-'----I ,II ,,-/' " . ~ "". I ~~ I ~ ______ ~ ____ ~ I· 1 H-' ~ M g -.--}--;;=-.:='--------- H------------1----~~--_7HII I ~'Hl------I ----ROBIE ST I 0: o I I I I I I , I , I I I I I I I I 1 ." N g ~ .~ . ( -........ . . ' /' ~. '-, I .. I 1 , I :1 " I I "-PROI'DnY UN£'. T'rI', I I 1 I I I I I I I STREAM BUFFER REMEDIATION EXHIBIT ~ DATUM: NAVD -88 lUM IHI or II ( !'itlUTH NlUO(RO!'aA SF~II I'IIO.l"cr WllltAtl O1VA11OtI or 1OOS.l7IUhVJQOj-700l1J11 tf~\1111q WIo..",tlS£() ron II F. VERTICAl. UAnlM FaUll.'; 5/13It alB ORf01NAL PR9AftAnON loW'. I I I I I I I I I I I I I I I I SCALE: PAOJ ,: HORIZONTAL: ""~ ' •• &0' DRAWN: VERTICAL.: fUMtweD: NI .. U .. 11 l1li. :::~~wr.'I!. Clstnl1. :UI'f\{'I'I¥l trw,..: "C" X "'.N""~ WLY~ ",W N."!! REMEDIATION J . LEGEND -.. -.. -•. -ORDlHNlV HJeII WAru "ARK (CHWM) ------EXlsnN~ SlREAII BUf'F£R OEUH£AnON D ElQSnNC SlREAII 9U<f£R AREA ImII AREA 01' STREAM BVf'F£R IIoIPAcr 2J.B77 .f AIIEA OF SlREAI! DUmR RD.lEDlAnoH 2-4,1371r P R D PAINTED HILLS IMPACTS COMMERCIAL: 5,921.97 SF +1 13416 SF 7,056.13 SF RESIPEN]AV 8,725,60 SF mA!l smEAt.!: 3.324.75 SF +781.68 SF +24966 SF 4,356,09 SF mAil REMEDIA]ON' 985.66 SF RIGHT OF-WAY: 2,752.90 SF TOTAL -23.876.38 Sf REMEDIATION REMEOIAnON: 24,136.34 SF z = w $ IJ) ~ CRAPHIC SCAlE 50 ~5 50 ~.~A--' .,- ( IN fIET ) 1 Inch _ 50 n. SHEET ilWCE STREAM BUFFER EXHIBIT 1 OF 1 W.1~C(,"'!lr.W(l(JY.oII!!.It; DISHMAN· MICA RD. JOB NUMBER :!.."'O.s::tt1Il~LNA.'i",.\:) L"::w.·ItWrt~tvW" (f.r,.'1';. SPOKANE VAUEY,WA 13-1166 r'I' .. '·.)!mMI"AJI;!...o~'X'"/1 l -1 • 1 J . , 1 I -J I -' BUILDING RESTRICIONS _lNIDOCIIPC ~ -.y IDDICI1U) 10 mc;u _ _ UIII1I<JII.Y IU1IICIID 10 :t1 " au.-~ AT ID1H I'IIONlITt lJlCZ ~.,:= t=-r.cu.y UNIT/LOT DATA ljZJ6!rn 0 !~ t;HCJE EN"" n 2M 70 J.l IIO-t:I .31 eo 42 00IJhll' D!!1 40 .. 30 20 TClTAIS ""Il1011l UlXED US( ... ns rr LOll ~LOlI"JlTUII1!I .. • 10 24 PROPERTY AREA SE • SEC.33. T .2SN .• R.44E •• W.M . SW*. SEC.34. T.2SN •• R.4 4E •• W.M . NE~. SEC. 4 . r24~ .. R.44E .. W.M. 1 MULTI-FAMILY 1 1 _95 AD. SCALE: ItOmZONTAI...: 1'.'30' vs:mICAL; N/A PRO .. '; CAll!: DRAV",: R!\IIR:WI!D: oo''OGJfO AWCE GUO '''·If ... .tCOl.~''.t\IHlU11C :-_·I'r.:rn"~LUIJ,r.~ TI1W :'I(M t-" ... .uC,\·nu.':.H 10:16 Ut~tr.x""\:.co'''':I.'J' \ "\ \-r~';~::;.~) -/--'-.-':.--.. --,-10 \ ,. I I I I I I P R D PAINTED HILLS SITE 1 LAYOUT (PRO) DISHMAN· MICA RD. SPOKANE VALLEY,WA I . __ ." ~ i\ • I , .::~~;:J:;-~: SHEET 1 OF 1 olOHNUMnEn 13-1166 l ~ J l J .J J . 1 J J I i '.! ~., ... !J f\j '-I <: ,'" .. "'t-: .C; ."C: .... -"' .. (~ "0 ~ I I I I I I I I I w > <! ~--------~---------+HHa a: [1") ____ ROSIE ST I a: a 'i , .. M 0 -~ • 0 ~ " . . " 0 -~ CD u . ~. pnOPERly UNE. T'rP. o STREAM BUFFER REMEDIATION EXHIBIT \. SCAt(, I-.SO· :) \ (T-) I"~ ~ ~ DATUM: NAVD -88 TT'.M tr:. OF 111[; ooun Il'OIurnDr/l rB',foR NlO.ECI VI1JII m £1 rvMY.)IIOr::xc:. nf 114-';"1l?'J) .. ;'O)1 rJl SE • SEC.33. T.25N .• R .44E., W.M. SW~, SEC.34, T.25N., R.44E .• W.M. NEt, SEC. 4, T .24N., R.44E., W.M. ,-+-~.....,I N EATI 0 N, -z.. 0 V\ ~ '"2: () 1'1 C 2-D t', (! I ;:z SCALE: PROJ#: 1;1·'\00 ~l:U::1~-"'" HORIZONTAL: DATe: Ol/tO/tD \ • .11'.'['1 ... ..:; ~';I..-'''. t'-tiO' DRAWU: OLD X Iv.'~j"~ ~Rl1c,lL: U-"!""~' n~I!Y~O: mw :':>lJJI W. IU·'".'U:JI\','A::itr..lOron 1It:\'Um:ll. [V.IUt.(fOI1I1&ro • 311:1'1 OlO ORIOINALPRt:.PAnATlON tW' ~ •• _001---_ ... ---___ OJ- LEGEND -•. -•. -.• -ORCtUARY HIQi WATeR U}.RK (OH'AU) ------EXISTING STREAU Blf'FLR OWH(ATIOU D [XlSTI"G Sm[Au DUFFDI .... E. z --= w $ (JJ 3 CRAPHIC SCALE \0 0 25 so 100 ' ... ~I(·.t Cl. .... ~.u.·,"l( ....... '.·llr. :--..:r""';',.:'J L·"A.·~I.:~') ~M·;"w~L!"1.r';'\!);CIf< III !"'l~~:-:'U I,I,J' :~'1:'''''r...:r:1 :Z20~D " I"±PElzt J:=z3::::=;i 22(j7~ sf P R D PAINTED HILLS STREAM BUFFER EXHIBIT DISHMAN·MICA RD. SPOKANE VALLEY,WA I IN <to ) II~h-50/t. SHEET 1 OF 1 JOaUUM&A 13-1166 I J J J I J J J Zone 3 -Buffer Replacement Area on East Side of Chester Creek 200 plants in patches Common Name Trees Large shrubs Small shrubs Total Ponderosa pine serviceberry Rocky mountain juniper chokecherry mock orange Wood's rose common snowberry Phlox sp. Scientific Name Pinus ponderosa Amelanchier alni/oloia Juniperous scopulorum Prunus virginiana Philadelphus lewisii Rosa woodsii Symphoricarpos albus Phlox speciosa or longifolia # Planted 22 33 30 20 30 20 25 20 200 Zone 4 -Wildlife Travel Corridor on East Side of Chester Creek 400 plants in patches Common Name Trees Large shrubs Small shrubs Total Ponderosa pine serviceberry Rocky mountain juniper chokecherry mock orange Wood's rose common snowberry Scientific Name Pinus ponderosa Amelanchier alni/oloia Juniperous scopulorum Prunus virginiana Philadelphus lewisii Rosa woodsii Symphoricarpos albus # Planted 50 60 30 50 60 70 80 400 Shrubs shall be planted in the approximate prescribed quantities depending on plant availability. Large shrubs should be planted in clusters on 10-foot centers. Small upland shrubs should be clustered on 3-6 foot centers around large shrubs. Depending on availability, the mixture of grass species listed below should be drill seeded or hydro seeded at a density of 22 pounds PLS per acre in all disturbed areas. Grasses should be planted during the growing season when precipitation and temperature levels will insure germination and survival. Grasses should be planted early in the fall so that the crop is well established by October 15. If gennination, growth, and root development are substantial before the end of the growing season, some degree of erosion control will be provided during the winter and spring months that follow. It may be necessary to irrigate the soil surface to keep it in a moist condition for the first two weeks after seeding. Irrigation should supplement rainfall as required to achieve a total from combined sources of 2 inches per week and no more than 0.25 inches per hour. Seed can also be installed to lie dormant over the winter and germinate in the spring. Grasses Common Name bluebunch wheatgrass Idaho fescue prairie junegrass Total Scientific Name Agropyron spicatum Festuca idahoensis lroeleria cristata 24 Bunch or Sod B B B PLS (lb/acre) 8.0 6.0 8.0 22.0 .J ...J 6.2: FEMA Mitigation Requirements All work on the levee and embankment shall be completed in strict compliance with FEMA requirements using the US Army Corps of Engineers manual titled Guidelines for Landscape Planting and Vegetation Management at Levees, Floodwalls, Embankment Dams, and Appurtenant Structures (ETL 1110-2-583 dated 30 April 2014). The manual states that all vegetation not in compliance with the ETL shall be removed. The removal of noncompliant vegetation includes trunk, stump, root ball, and roots greater than 112 inch diameter in the levee, or within 15 feet of the flood damage reduction structure. The following paragraphs have been inserted from COE manuals for reference. The conditions listed below shall be strictly adhered to, but project construction shall not be limited to the conditions listed below, but must be in compliance with all conditions in the referenced COE manual. "The only acceptable ground cover in the COE mandated vegetation free zone is perennial grasses to prevent erosion. Noxious weeds are not tolerable. The grass species must not grow to exceed 12 inches in height and be tolerant of mowing to a height of 3 inches to allow levee inspection at least once per year. It will be necessary to mow, burn, or graze to inspect for and control pests, weeds, and burrowing animals, repair damage to the embankment, and maintain the grass cover crop. Woody vegetative plantings prescribed for mitigation in this report shall not be placed in the levee, or within 15 feet of the flood damage reduction structure. The native grass species selected for the project shall be appropriate to the local climate, conditions, and surrounding or adjacent land uses. BSW recommends a sod type species, not a bunch grass type, should be selected or prescribed by COE, will tolerate mowing to heights as low as 3 inches as follows: "at least once each year for inspection, and in anticipation of flood conditions and associated monitoring and flood-fighting activities. b. If the local climate, hydraulic and hydrologic environment, soils, or other conditions will not support such grass species, then non-vegetative means of erosion control shall be employed, e.g., riprap, pavement, articulating concrete mats, or other engineered surface. c. A maximum grass height is specified for embankment dams and their appurtenant structures (see Paragraph 3-4c, "Vegetation-Free Zones")." "Paragraph 3-4c. Vegetation-Free Zones. Vegetation-free zones shall, when dry, be mowed to a height of 3-6 in. at any time the grass reaches a height of 12 in .. Mowing shall be triggered by grass heights of less than 12 in. if important to the health maintenance of the particular grass species. The maximum height of grasses shall be 12 in." "5-2. Operations and Maintenance Manual. For each project, it is important that the O&M manual include an annual maintenance program to control animal burrows and vegetative growth. It is also important that vegetation be managed in such a manner as to avoid the need for mechanized removal and associated embankment repair, and avoid any incidental growth and subsequent presence of endangered species that might prohibit access and activities necessary for O&M. 5-3. Removal of Non-Compliant Vegetation. a. All vegetation not in compliance with this ETL shall be removed. A detailed removal plan shall be submitted to the local USACE District Levee Safety Officer for review and comment before removal of vegetation. The removal plan shall expand on the following basic requirements. (1) By excavation, remove the trunk (or stem), stump, rootball, and all roots with diameters greater than ~ in. All such roots in, or within 15 ft of, the flood damage reduction structure shall be completely removed. (2) Assure that the resulting void is free of organic debris. (3) Fill and compact the void according to the original soil and compaction specifications: or, if no specifications exist, match adjacent soil and compaction. b. Removal of non-compliant vegetation can create significant issues for the 25 1 ...J owner/operator, as maintenance may require environmental permits. The local sponsor must coordinate with the Corps and other appropriate agencies and obtain all the required environmental permits (including Corps of Engineers 404 permits) before conducting work within the levees. Mechanized land clearing below the plane of the "Ordinary High Water Mark" will normally require Clean Water Act permits before work can commence. (Note that "Ordinary High Water Mark" is defmed in 33 CFR Part 328.3(e)." A grass seed mixture recommended or approved by FEMA and/or COE must be applied on the approximate 200 lineal feet of levee that will be raised by one foot and all peripheral embankment areas where the vegetation is temporarily disturbed by equipment. The agencies should prescribe one grass seed mixture for the Riparian Area (wetland species) and one for the adjacent upland. A list of suppliers who will prepare the prescribed grass seed mixtures and supply nursery stock specified in the vegetation plan follows. Grass seed: Grassland West PO Box 489 908 Port Drive Clarkston, W A 99403 1-800-582-2070 Trees, & Shrubs: Plants of the Wild PO Box 866 Tekoa, W A 99033 509-284-2848 6.3: Ponderosa Pine Planting Wildlife Habitat Institute 1025 East Hatter Creek Road Princeton, ID 83857 208-875-8704 ALWAYS plant after December 15 and before March 31. Plant ONLY conservation grade seedlings 20-24 feet from fast growing deciduous trees. Plant seedlings on 30 foot centers with no shrubs inter-planted close to the trees to prevent shading and competition that greatly reduces survival. A mulch of Ponderosa pine needles applied in a 3-6 foot radius around the tree trunk at planting will greatly reduce competition and increase tree survival. Ponderosa pine out-planting survival following Rhizopogon rubescens inoculation is 2-3 times higher compared to non-inoculated. Numerous studies have shown that ectomycorrhizal fungi can profoundly affect conifer performance by facilitating nutrient and water uptake, maintaining soil structure, and protecting roots from pathogens and environmental extremes. A specific ectomycorrhizal fungus, Rhizopogon rubescens, inoculated onto the root systems of Ponderosa pine seedlings greatly increase survival. Irrigation options are being explored at this mitigation site, but the landscaper should buy plants that have been inoculated or dust the planting holes with this fungi if it is available. 6.4: Additional Planting Guidelines Depending on availability, the mixture of grass species listed above should be seeded at a density of 25 pounds PLS per acre. Grasses should be planted during the growing season when precipitation and temperature levels will insure germination and survival. Grasses should be planted in early April so that the crop is well established before dry weather, in the fall so that 26 the crop is well established before October 15, or donnant seeded late in the fall so the seed will not germinate until spring. Site preparation and planting should occur in the fall and winter. Seeding rates of live, germinable seed or Live Pure Seed (LPS) are a product of seed lot purity and germination percentage. LPS calculations are based on the number of seeds per pound and the number of seeds per square foot at one pound per acre. A nursery will prepare a custom seed mix with the prescribed LPS for each species. Trees and shrubs should be planted after the end of the growing season when the plants are donnant. The best time to plant is late winter when sub-zero temperatures are over but plants are still donnant. Plants may be planted any time during the growing season when the daytime high temperatures are 70F or cooler if irrigation is available from the time of planting through the rest of the growing season. Each tree or shrub planted should be clearly identified with an easy to identify tag that identifies the species. Without such identification it is impossible for the monitoring biologist to tell which plants are enhancement plantings and which are native to the site. 6.S: Additional Site Protection Measures Many people drive, park and passively enjoy recreation in the area so the enhancement areas must be protected from human traffic after planting. Signs should be posted every 100 feet to explain the sensitivity of the newly planted areas and discourage foot traffic in newly seeded areas. Pennanent signs with Riparian Buffer Area, Natural Area Do Not Disturb, or similar language should be posted around the areas protected as riparian buffer. 6.6: Timeline for Construction Due to the appeals process, it is very difficult to predict when construction will be permitted. It is very unlikely that construction will begin in 2016, more likely that construction will begin in 2017. Regardless of which year construction begins, it is known that the first construction phase will include the stonnwater plan and the levee work. When that work is completed, disturbed areas will be reclaimed and planted in accordance with the tenns of this mitigation plan. BSW will monitor site impacts and mitigation work to insure the work is completed as specified in this plan. The five year monitoring requirement for each phase will be implemented as described below. 6.7: ESA and FEMA Compliance The purpose of this report is to confinn that the project is in compliance with Sections 9 and 10 of the Endangered Species Act. The proposed flood control and floodplain changes will have no effect on any listed species. For the Chester Creek Main Channel (golf course overflow reach) most of the 1% annual-chance floodplain within the project site is effectively being intercepted and directed to the infiltration facilities located on the north end of the project area, rather than entering the existing golf course and infiltrating. For the Chester Creek Unnamed Tributary, the floodway and 1 % annual chance floodplain are being intercepted by the gravel pit infiltration facility just north of 40th, and are being removed from the FEMA mapping. These actions are simply enhancement of the existing facility and the proposed changes will have no effect on any listed habitat or species. 27 7.0 THE MONITORING PLAN All monitoring plans require that a mitigation site be monitored annually to determine whether the goals and performance standards have been met. Monitoring typically lasts for 5 years or until the City of Spokane Valley is satisfied that the conditions of the mitigation plan have been met. The site should be monitored in the spring to evaluate the success of weed control from the previous year and prescribe weed control for the current year. The monitoring will also evaluate plant survival to insure that performance standards for percent ground cover of native vegetation are met. Planting of the original grass seed mixture will be repeated to fill in problem areas if they occur. The City of Spokane Valley will be notified immediately after diagnosis of failing functions, hydrologic systems, or biological vitality and integrity of the plantings as determined through annual monitoring. The vegetation will be managed to insure 80% areal cover with native grasses after five years (year 1=20%, year 2-30%, year 3=50%, year 4=70%, year 5=80%). Tree and shrub stock will be monitored to insure 80% survival after 5 years. Reinforcement plantings will be performed annually as necessary to insure performance standards are met at the end of five years. This above Monitoring Plan refers only to mitigation plantings prescribed by BSW and does not apply to levee monitoring and maintenance that will be continued indefinitely and is outside of the professional capabilities of the undersigned. 8.0 LIMITATIONS Within the limitations of scope, schedule, and budget, BSW services have been executed in accordance with best available science and generally accepted professional practices for the conditions at the time the work was performed. This report is not intended to represent a legal opinion. Specifically, there is no positive or negative recommendation towards the purchase, sale, lease, or construction on the subject property. No warrant, expressed or implied, is made. Larry Dawes Principal Biologist Biology Soil & Water, Inc. 3102 N. Girard Road Spokane Valley, WA 99212-1529 Phone 509-327-2684 Email: bswinc@icehouse.net 28 , I _J BIBLIOGRAPHY AND SUGGESTED REFERENCES Berglund, Erwin R.. 1976. Seeding to Control Erosion Along Forest Roads. Extension Circular 885. Oregon State University Extension Service. 6-8p. City of Spokane Valley Municipal Code Carroll, Carlos; Noss, Reed F.; Paquet, Paul C. 2001. Carnivores as focal species for conservation planning in the Rocky Mountain region. Ecological Applications. 11(4): 961-980. Cooper, Stephen V., Kenneth E. Neiman, and David W. Roberts. 1991. Forest habitat Types of Northern Idaho: A second Approximation. USDA: Forest Service; Intennountain research Station. General Technical Report INT-236. 143 p. Dale, B. C. 1983. Habitat relationships of seven species of passerine birds at Last Mountain Lake, Saskatchewan. M.S. thesis. University of Regina, Regina, Saskatchewan. 119 pages. Daubenmire, R. 1969. Structure and ecology of coniferous forests of the northern Rocky Mountains. Pages 25-41 in R. D. Taber, ed. Coniferous forests of the Northern Rocky Mountains. Univ. Mont., Missoula. 395pp Davis, S. K. 2004. Area sensitivity in grassland passerines: effects of patch size, patch shape, and vegetation structure on bird abundance and occurrence in southern Saskatchewan. The Auk 121: 1130-1145. Delaney, Kevin. 1994. Wildlife Notebook Series. Alaska Department of Fish and Game, http:/www.hitime.com.sdscptn.htm. FERC. 2006. Draft Environmental Impact Statement. Spokane River and Post Falls Hydroelectric Projects. Federal Energy Regulatory Commission. Office of Energy Projects. December 2006. Fonnan, R. T. and M. Gordon. 1986. Landscape Ecology. John Wiley and Sons, New York. 619 p. Frissell, C.A. 1992. Cumulative effects of land use on salmonid habitat on southwest Oregon streams. Oregon State University, Corvalis, OR. Grubb, P. J. 1977. The maintenance of species richness in plant communities: The importance of regeneration niche. Biological Review 52: 107-145. Hitchcock, C. Leo, and Arthur Cronquist. 1994. Flora of the Pacific Northwest. University of Washington Press, Seattle, W A. 730p. 29 --, Hitchcock, C. L., A. Cronquist, M. Ownbey, and J.W. Thompson. 1964. Vascular Plants of the Pacific Northwest, Part 2: Salicaceae to Saxifragaceae. University of Washington Press, Seattle. 597 pp. Koehler, Gary M. 1990. Population and habitat characteristics oflynx and snowshoe hares in northcentral Washington. Canadian Journal of Zoology. 68: 845-851. Koehler, Gary M.; Aubry, Keith B. 1994. Lynx:. In: Ruggiero, Leonard F.; Aubry, Keith B.; Buskirk, Steven W.; Lyon, L. Jack; Zielinski, William J., tech. eds. The scientific basis for conserving carnivores: American marten, fisher, lynx, and wolverine in the western United States. Gen. Tech. Rep. RM-254. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station: 74-98. Koehler, Gary M.; Brittell, J. David. 1990. Managing spruce-fir habitat for lynx and snowshoe hares. Journal of Forestry. 88(10): 10-14. Koehler, Gary M.; Hornocker, Maurice G.; Hash, Howard S. 1979. Lynx movements and habitat use in Montana. The Canadian Field-Naturalist. 93(4): 441-442. Maher, W. J. 1973. Matador Project: Birds 1. Population dynamics. Canadian Committee for the International Biological Programme, Matador Project, Technical Report 34. University of Saskatchewan, Saskatoon, Saskatchewan. 56 pages. Mancuso, Michael, December 2000. Field Investigation for Spiranthes Diluvialis (Ute Ladies- tresses) on BLM Lands Managed by the Shoshone Field Office, South-Central Idaho. Conservation Data Center Martin, A. C., H. 1. Zim, and A. L. Nelson. 1951. American Wildlife and Plants. Diver Publications, Inc., New York. 484 p. McCaffery, K. R., and W. A. Creed. 1969. Significance of forest openings for deer in northern Wisconsin. Technical Bulletin 44. Madison: Wisconsin Department of Natural Resources. 104 p. Moseley, R.K. 1998. Ute ladies tresses Spiranthes diluvialis in Idaho: 1997 status report. Report prepared by the Idaho Conservation Data Center, Boise, ID. Murray, Dennis L.; Boutin, Stan; O'Donoghue, Mark. 1994. Winter habitat selection by lynx and coyotes in relation to snowshoe hare abundance. Canadian Journal of Zoology. 72(8): 1444- 1451. NatureServe. 2010. NatureServe Explorer: An online encyclopedia oflife [web application]. Version 7.1. NatureServe, Arlington, Virginia. (PBTTAT) Panhandle Bull Trout Technical Advisory Team. 1998. Coeur d'Alene Lake Basin bull trout problem assessment. Draft. Prepared for the State ofIdaho. December 1998. 30 Sauer, J. R., J. E. Hines, and J. Fallon. 2005. The North American Breeding Bird Survey, Results and Analysis 1966 -2004. Version 2005.2. USGS Patuxent Wildlife Research Center, Laurel, MD Simpson, J.C., and R.1. Wallace 1982. Fishes ofIdaho. Department of Biological Sciences, University ofIdaho, Moscow. Singer, F. J. 1979. Habitat partitioning and wildlife relationships of cervids in Glacier National Park, Montana. Journal of Wildlife Management. 43(2):437-444. Spokane County Public Works Department: Building and Planning Division. 1996. Critical Areas Ordinance for the Protection of Wetlands, Fish and Wildlife Habitats and Geo- hazard Areas. Spokane County, W A. 69p. Stephens D. A. and S.H. Sturts. 1997. Idaho bird distribution. Idaho Museum of Natural History, Pocatello and Idaho Department ofFish and Game. Boise, ID. USDI Fish and Wildlife Service. 2001. Endangered and threatened wildlife and plants: fmal rule to list silene spaldingii (Spalding's catchfly) as threatened. Federal Register. 66 (196) 51598-51606. Washington Department ofFish and Wildlife and the Upper Columbia Basin Working Group of Timber, Fish and Wildlife (TFW). 1996. Washington Department of Fish and Wildlife. 1996. Priority Habitats and Species List: Habitat Program. Olympia, Washington. 28p. Washington Fish and Wildlife Commission. 1997. Policy of the Washington Department of Fish and Wildlife and Western Washington Treaty Tribes on Wild Salrnonids. Washington Fish and Game Commission, Olympia, W A. 68p. Washington State Department of Fish and Wildlife, 1997. Integrated Streambank Protection, Bank Erosion Assessment and Technigue Selection Guidance, Section III, Biological Considerations. Water Quality Standards For Ground Waters of the State of Washington. Chapter 173-200, WAC. Wolff, Jerry O. 1980. The role of habitat patchiness in the population dynamics of snowshoe hares. Ecological Monographs. 50(1): 111-130. Zim, H. S., A. C. Martin, and A. 1. Nelson. 1961. American Wildlife & Plants: A Guide to Wildlife Food Habits. Dover Publications, Inc. New York, NY. 31 Appendix 1 U.S. Fish & Wildlife Service SPOKANE COUNTY Updated 8/29/2015 LISTED Threatened Salvelinus confluentus) (Bull trout) -Columbia River distinct population segment Howellia aquatilis (Water howellia), plant Silene spaldingii (Spalding's silene), plant Spiranthes diluvialis (Ute ladies' -tresses), plant Lynx canadensis (Canada lynx) Coccyzus americanus (Yellow-billed cuckoo) SPECIES OF CONCERN Bald eagle (Haliaeetus leucocephalus) (delisted, monitor status) Burrowing owl (Athene cunicularia) California floater (Anodonta californiensis), mussel Ferruginous hawk (Buteo regalis) Giant Columbia spire snail (Fluminicola columbiana) Loggerhead shrike (Lanius ludovicianus) Long-eared myotis (Myotis evotis) Northern goshawk (Accipiter gentilis) Olive-sided flycatcher (Contopus cooperi) Pallid Townsend's big-eared bat (Corynorhinus townsendii paUescens) Peregrine falcon (Falco peregrinus) (Delisted, monitor status) Redband trout (Oncorhynchus mykiss) Sagebrush lizard (Sceloporus graciosus) Westslope cutthroat trout (Oncorhynchus clarki lewisi) Vascular Plants Haplopappus liatriformis (palouse goldenweed) 32 I I ' • Appendix 2 Critical Areas Maps 33 IPaC Trust Resources Reporl Generated August 29,201607:52 PM MDT. IPaC'13.0.8 This report is for informational purpos es only and should not be used for planning or analyzing project level ilTlpacts. For project reviews that require U.S. Fish & Wildlife Service mview or con currence, please return to th e IPaC website and request an official species list from th e Reguiatory Documen ts page. IPaC -Information for Planning and Conservation (https://ecos.fws.goJillQac/): A project planning tool to help streamline the U.S. Fish & Wildlife Service environmental review process. U.S. Fish and Wildlife Service Trust Resources List Endangered Species Act Species List (Il.SFff7S E ndanf.!er ed Species PrOf.!ram). There are a total of 5 threatened or endangered species on your species list. Species on this list should be considered in an effects analysis for your project and could include species that exist in another geographic area. For example, certain fishes may appear Oll the species list because a project could cause downstream effects on the species. Critical habitats listed under the Has Critical Habitat colwnn mayor may not lie within your project area. See the Critical habitats within your project area section below for critical habitat that lies within your project area. Please contact the designated FWS office if you have questions. Species that should be considered in an effects analysis for your project: l.~~:~~= ... _~~~~=~~_~~;"~=.~==~~J~~)~J~~s.C_~~~~~~~itat =J~.::~~~ct.==,.=~~~J i Yellow-Billed C~ckoo l Threatened i ~peci es ! Proposed critical habitat I W~s~gton Fish And I ~~O:~::~~~;~:;~~~~. =._. L ___ L~l ~_~.=~~J:ld~lf~ OffiC~~~_J I Fishes ! , .. -." -:0._ ·3.;.:-:.:... ........ .,.. __ ··.""~ .. ~...-~ ... -C", .. ""'-I •• 'C"'OHLO ..... Ie· ~~""'~"''''''4~ ... ~ ..... -=.cu.-~r:;:.=..--.....::c...:''''''-=-~'''~I''''~<.LIo=-"", .. = .... .,....-..;..=-~ ....... ~~u:-.·J~~''~~~~. ~'"t ... ..". ••• __ ~~..r.:. ____ -=..:.;.W;s' ... -n ____ : I Bull Trout 1 Threatened I species I Final designated criti cal l Washington Fish And I ; (Salve linus confluentus) ~ ~ info I habitat ! Wildlife Office I i~~i~f:::I~:~~:~~=:~~=:l~ ..... ~ __ L~c_ .. L __ ~_J~-.~~~"-~ 1 ••• M • ~=~"~.-.'.-'~~='~'--. ~"~'~""~."'-~~M=_·~. <'"T·'~~~~~~~"~-~-~=r'~~-·~~'~~'=~'=·'~-~-~"~~··T,·'~=-'~~~. ~~~=~"'~~.~ i Spalding's Catcbfiy 1 Threatened I species ~ 1 Washington Fish And I ! (Silene spaZdingii) [I info ~ ~ Wildlife Office i j •• :::,-.-;;;,u:t·~ " ........ ""I_.l~~J'!'_~=~~_-::..o:-":~n--:" ... .;Lr; .. =:".:_~~~_-=-~~=~J'~a:-~~~~g~_~.:=:=-.....c-..:oo..,.-r=~~~-.. .=-~,;,.""i= ...... ,......2:.l ... ·~=""'" ... ....-===-... ~ ..... ........, -, : Water h~wellia .. i Threatened! ~pecies ! ~ W~s~gton Fish And I (Howellza aquanlzs) ! I mfo ; I~ WIldlIfe Office i I·' , .•••. -=~= .. ~ .... ~= ~>~.~=~u.~_.=.~~,~=.~~='-.._~ =~~.,~~~~~.$=,.-. --·"=~~=~=~.!!-=~.n~~=. -=-'~~~.~~'J ,Mammals I .I'~ ~"'-"".-.~--_~ ..... _ .... _ .... " .... ___ .,... -..-..;n","-__ ", ... ___ .. "T-• ....-..r>_~ ..... :-..... _~~_--...-.-~~ ... ~ ................ UQ~"""""'~AJ~ ___ ~ _~=.o.--= ... :c:_~~·_~.~"-.... __ ..a1l<7~-rco".-. ..... --..:-.. -=1 ! Canada Lynx . 1 Threatened ! ~pecies ! Fin~l desilrnated clitical ! W~sh~ngton Fish And I I (Lynx canadensls) l ~ 111fo i ha bltat I WIldhfe Office I Population: (Contiguous U.S. DPS) II! ~ i ~ _____________________________ 1· __________ ' I • Critical habitats within your project area: There are no critical habitats within your project area. 0412112015 Information, Planning, and Conservation System (lPAC) Version 1.4 Page 3 of7 47"3726"N 47" 36'2B"N :: ~ ~ 9 :: ~ ~ 9 4ilO4OO N A Soil Map-Spokane County, Washington 480700 481000 481300 481600 481900 Map Scale: 1:12,700 if printed on Aiandscape (11" x 8.5') sheet = __ -=====-______ -========MetelS o 150 300 600 900 == ____ ~==== __ ==_= ______ ~==========~t o 500 1000 2000 3000 Map projection: Web Mercator Comer ooordinates: WGS84 Edge lies: UTM Zone llN WGS84 USDA Natural Resources Web Soil Survey National Cooperative Soil Survey ,-= Conservation Service r I 482200 482500 482800 I :: ~ !'.I 9 ~ ~ ~ ~ ~ i 483100 :: ~ (:l 9 4/1/2015 Page 1 of 3 47" 3726"N 47" 36'2B"N I l Soil Map-Spokane County, Washington MAP LEGEND Area of Interest (AOI) o Area of Interest (AOI) Salls I' , _.-l Soil Map Unit Polygons Soil Map Unit Lines o Soil Map Unit Points Special Point Features 'l2> Blowout i2Sl Borrow Pit )( Clay Spot Closed Depression '. / Gravel Pit , ....... Gravelly Spot q} Landfill ; Lava Flow ,'. .::::, .. Marsh or swamp .:~~~. Mine or Quarry @; Miscellaneous Water 0 Perennial Water Rock Outcrop -i-Saline Spot Sandy Spot =. Severely Eroded Spot Sinkhole Slide or Slip Ii Sodic Spot USDA Natural Resources -~ Conservation Service r -I I Spoil Area .-Stony Spot .. "', Very Stony Spot ." Wet Spot Other .-Special Line Features Water Features Streams and Canals Transportation +++ -" Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography Web Soil Survey National Cooperative Soil Survey MAP INFORMATION The soil surveys that comprise your AOI were mapped at 1 :24,000. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: Survey Area Data: Spokane County, Washington Version 5, Sep 4,2014 Soil map units are labeled (as space allows) for map scales 1 :50,000 or larger. Date(s) aerial images were photographed: Jun 4, 2011-Jul 5, 2011 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. 4/1/2015 Page 2 of3 1 l -, -1 l l l J ••• I Soil Map-Spokane County, Washington Map Unit Legend r..aPU~ifSYm~bl · .. ' 1040 1080 1200 3022 3054 3130 5040 5041 5073 7101 7110 7122 7170 7181 Totals for Area of Interest Natural Resources Conservation Service . :. r.,.ap.Un~Nai11e: '.' .. ' . Acre~dilA61 ..... Hardesty ashy silt loam, 0 to 3 percent slopes Narcisse silt loam, 0 to 3 percent slopes Endoaquolls and Fluvaquents, o to 3 percent slopes Bong ashy sandy loam, moist, 0 to 8 percent slopes Clayton ashy fine sandy loam, 0 to 8 percent slopes Phoebe ashy sandy loam, 0 to 3 percent slopes Spokane-Swakane complex, 3 to 15 percent slopes Spokane-Swakane complex, 15 to 30 percent slopes Lenz-Rock outcrop complex, 15 to 30 percent slopes Pits-Dumps complex Urban land-Opportunity, disturbed complex, 0 to 3 percent slopes Urban land-Marble, disturbed complex, 8 to 15 percent slopes Urban land-Springdale, disturbed complex, 0 to 3 percent slopes Urban land-Phoebe, disturbed complex, 3 to 8 percent slopes Web Soil Survey National Cooperative Soil Survey .' .' ; 14.4 108.4 61.9 14.3 7.2 29.2 7.9 43.1 37.6 12.0 11.4 0.1 153.0 112.9 613.5 "/'''.' . . ~P~ri:e!i('~fAdl ~ . ,.::': 2.3% 17.7% 10.1% 2.3% 12% 4.8% 1.3% 7.0% 6.1% 2.0% 1.9% 0.0% 24.9% 18.4% 10D.D% 4/1/2015 Page 3 of3 User Remarks: ,- This map II for (lonor,,' roferonco only. Tho US Fish and Wlldllfo Service Is not rosponslblo for tho uccurocy or currontnoss of tho bll60 dato shown on Ihls mup. All wotland, rolalod dolo should bo usod In accordanco with tho lavor motndota found on Iho Wotlands Mopporwob Glto. May 14, 2015 Freshwater ErnllrgeJlt Freshwater Foresled/Shrub Estuarine and Marine Deepwater Estuarine and Milrine Freshwater Pond Lar.e Rlvorine Other Alb uJe.tb vJ h'1!rtJl?} 7 ... T e<+her I ad'-~ , »0 T "-we-il dY,-,I. r r 1 -1 l SITE ELEMENT PLAN I , .J _J .J l J --' .J o « o ~ ~ II.! ID .J CHESTER CREEK DR /' EXISTING BOX CULVERT CHESTER CREEK ~ N 100' STREAM BUFFER WtE 5 GRAPHIC SCALE 200 0 100 200 400 Io.c." I I I ~. 1 1 ( IN FEET ) 1 inch -200 ft. ~ DATUM: NAVD -88 T8M $.5 OF THE SOUTH PONDEROSA SEWER PROJECT WITH AN ELEVATION OF 2005.87 (NAV029)-2009.67 (NAVDaa) WAS USED FOR THE VERTICAl DATUM FOR THIS MAP. ROADSIDE INFIL TRATION POND SETTLING POND STORAGE AREA #6 UNDERGROUND SERVICE ALERT ~:I1I~: ~ emaYOUDIQ TRIANGLE POND ~=~======~~>A~= 40TH AVENUE INFIL TRA TION FIELD SEE GUSTIN PIPE PLAN SET FOR MORE DETAILS 11 __ - BIOSWALE HEADWALL & EASEMENT TO BE RED AT FINAL PLAT T 1 I I ROADSIDE SWALE (TYPICAL) ~----T 18" CULVERT STORAGE AREA #1 2-48" RCP CONVEYANCE 2-48" RCP CONVEYANCE , TEMPORARY DRAINAGE EASEMENT 100' STREAM BUFFER EXISTING LEVEE 18" CULVERT 18" CULVERT 2-48" RCP CONVEYANCE STREAM BUFFER IMPACT MITIGATION 18" CULVERT AREA TEMP , --~ DRAINAGE EASEMENT 2-48" RCP CONVEYANCE LL ~~i~~~~ 2 B--14-1 JPP REVlSED PLANS 3 EXISTING 15" CMP CULVERTS TO BE REMOVED THORPE RD BO X CULVERT 30'W X 3'H BOX CULVERT SCALE: PROJ II: HORIZONTAL: DATE: 1· = 200' DRAWN: SEE GUSTIN PIPE PLAN SET FOR MORE DETAILS EXISTING 36"CULVERT , FUT\JRE TRACT/BORDER UTiUTY EASEMENT ~ 2B' ROW 1-1--------30' ~ I EXISTING " i ~ -l H ' , GROUND ~ __ 1 1---I ~:::===============1 I 10' MEANDERING , I PATH ROADSIDE SWALE l'--JOf\. 16' I : ~POSED 2-48" Rep PIPE ~M~A~D~IS~O~N~R~D=-~E~A~S~E~M~E~N~T~P-=L~A~N~ ______________ -----0- NOT TO SCALE X ""'L LiWCE 13-1166 smucruRAL SU~G 08/14/18 TlWAC JPP PlANNING WHIPPLE CONSUlTlNGENGINEERS LANDSCAPE 2528 NORTH SlA.lJVAN ROAD PLANS NOT APPROVED BY AGENCY SPOKANE VALLEY PAINTED HILLS PRD SITE ELEMENT PLAN DISHMAN·MICA RD. City of Spokane Valley ProJectIPermit No.: SUB-Z015-OO01 (Subdivision) FPD·2016-0007 (Flood PI .. ]n Development) EGR-2016-OO66 (Engineered Grading) City of Spokane Valley Development Engineering M .. $tTMI .... II -"*"'= ___ DNol RMe'Md o Revl~d forConforrnnu to Stru t5und&rd.and Acupted perChaplu 1.2 DateAccepted __ AccepUlluCornmenu SHEET C1.3 1 8-12-1 JPP ORIGINAL PREPARATION VERTICAL: REVlEWED: TRW OTHER SPOKANE vAlLEY. WA 99216 SPOKANE VALLEY,WA JOB NUMBER 13-1166 NO. DATE BY REVISIONS N/A PH:509·1!93-2611 FAX:.509-92f5.0221 J J J .J J 100 Year Flood Event Thorpe Road Crossing 64 cfs with Channel South of Thorpe 91 cfs without Channel South of Thorpe Madison Hills Flow to Culverts 15 cfs through 4 -18" Culverts Gustin Pipe Flow to Triangle Pond 16 cfs through 36" Culvert under Highway 27 I \ I ,-.. I II n r', I • J J J Ben Goodmansen From: Sent: Ken Puhn <kpuhn@westconsultants.com> Monday, July 16, 2018 8:37 AM To: Ben Goodmansen Subject: requested info for Painted Hills Ben, Per our conversation you had requested confirmation of water surface elevations in the vicinity of the Madison culverts and also the flood discharges entering your facilities. The 100-year water surface elevations calculated by our XPSWMM model within the Madison pipes are shown in the table below. The 100-yr discharges are shown in the 2nd table below. Note that the levee breach discharge came down slightly once I had the final design in the model. Let me know if you need anything else. Ken Node Max 100-yr WSE Pipe_Inlet 2009.49 SDMH 1B 2008.30 SDMH 1A 2008.12 SDMH 2A 2007.61 SDMH 2B 2007.86 SDMH 38 2006.51 SDMH 3A 2006.14 SDMH 4B 2005.64 SDMH 58 2004.63 SDMH 4A 2004.11 SDMH 6B 2003.99 SDMH 5A 2003.81 Pipe_Outlet 2003.71 US of 2003.72 Spreader 100-yr Location 100-yr levee (cfs) breach (cfs) Gustin Ditch Downstream of Hwy 27 16 n/a Golf Course Overflow @ Thorpe 64 91 Golf Course Overflow plus Madison hills inflows 79 106 1 J System Capacity Box Culvert Capacity 216.4 cfs @ 2 ft of depth, 1 ft of Freeboard Madison Mainline Pipe Capacity 154.32 cfs & 3.8 ft of depth Bio Filtration Channel 269.86 cfs @ 6 ft of depth Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Thursday, Jun 72018 Box Culvert Capacity Rectangular Highlighted Bottom Width (ft) = 28.33 Depth (ft) = 2.00 Total Depth (ft) = 3.00 Q (cfs) = 216.40 Area (sqft) = 56.66 Invert Elev (ft) = 1000.00 Velocity (ft/s) = 3.82 Slope (%) = 0.50 Wetted Perim (ft) = 32.33 N-Value = 0.040 Crit Depth, Yc (ft) = 1.22 Top Width (ft) = 28.33 Calculations EGL (ft) = 2.23 Compute by: Q vs Depth No. Increments = 30 N -\j()'\lA~ ~~ ~ SQS tl\ ~\\ ~~ S-l1 ~otk \~1\~-:r0c)~~ ¢ ~\~\f>.< Elev (ft) Section Depth (ft) 1004.00 ---,-----,.------,.------.---------,----.--------,----.,.--------,-4.00 1003.00 --+----t-----f----+-----+----j-----t---.---I-----t-3.00 1002.00 v ' -1-----+----+----1----=='(:-----1-----1--"1--1-----+-2.00 1001 .00 --i-----t----t----t------t----t-----t---t--t-----t-1.00 1000.00 -l-----+-----+----+----+---+----+--~-j-----+-0.00 999.00 ----L ___ --L--__ ----'-___ -'---__ --l. ___ ---'--__ ------'-___ -..I--__ --l._ -1 .00 o 5 10 15 20 25 30 35 40 -.J Reach (ft) Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Madison Pipe (1-48 in Pipe) Circular Diameter (ft) Invert Elev (ft) Slope (%) N-Value Calculations Compute by: No. Increments Elev (ft) 1005.00 1004.00 1003.00 1002.00 1001 .00 1000.00 999.00 o = 4.00 = 1000.00 Highlighted Depth (ft) Q (cfs) = 0.25 fe,. '''' 6fe '/-0/ = 0.013 / > r<~ 1"1 Area (sqft) Velocity (ft/s) Wetted Perim (ft) Crit Depth, Yc (ft) Top Width (ft) EGL (ft) Q vs Depth = 20 .. / . - '1 . - .. \ 1. /lfE HPJ X PLvt..V' 2. 11.:17£ MI't Y. FL (/w Section ---" ----. ---:::; ~ ~ . . .~ . -\ .. / . - '" "'----~ V 1 2 3 4 5 Reach (ft) 6 Tuesday, Jun 192018 = 3.80 = 77 .16 ~ = 12.34 \ = 6.25 = 10 .78 = 2.66 = 1.73 = 4.41 Depth (ft) 5.00 4.00 3.00 2.00 1.00 0.00 -1 .00 -, J Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Thursday, Jun 7 2018 Bioswale Capacity Trapezoidal Highlighted Bottom Width (ft) = 6.00 Depth (ft) = 6.00 Side Slopes (z: 1) = 3.00,3.00 Q (cfs) = 269.86 Total Depth (ft) = 6.00 Area (sqft) = 144.00 Invert Elev (ft) = 1000.00 Velocity (ft/s) = 1.87 Slope (%) = 1.00 Wetted Perim (ft) = 43 .95 N-Value = 0.175 Crit Depth, Yc (ft) = 2.64 Top Width (ft) = 42 .00 Calculations EGL (ft) = 6.05 Compute by: Q vs Depth No. Increments = 20 Elev (ft) Section Depth (ft) 1007.00 ---r----,----,----r----r---,..-----,.----.-------,-----,---....-------r-7.00 1006.00 1005.00 1004.00 1003.00 1002.00 1001.00 1000.00 ~. ----+--+.~--+---I-----+-~=-~-+--+-----+---I+-!..,....--I----II--6.00 -t------+-~\ -t------t---t---!--i-----+-----1/_~.. ---+---+-5.00 .\ _. . -t------+----t-'\--\ __ :1---_ ---t---t--+----+--;t7/--t----+-----t--4.00 -+----+----t-~\+--_\--+---t---t---t/--:--. -F--t---I--__+___+_ 3.00 -+----t----t----t----T-\----t-__ :~ ~!~. _.-: -t--t---J----t--2.00 -+----I---1----+-----Ti\-:. _--t---j-+---:./'--+----+-------i-+----+-1.00 -+---+---t----+--+----lo-t---~---+----t----t---+----t-0.00 999.00 ---L __ -L-__ .l.-_.--L __ -'--__ L--_-'-__ -L-_----' __ ---'-__ ...l.....-_--'-_ -1 .00 o 5 10 15 20 25 30 35 40 45 50 55 Reach (ft) I n r I -' BOX CULVERT/CONCRETE CHANNEL CALCULATIONS -I -I l 1 I -.-J PIPE SYSTEM CALCULATIONS MADISON ROAD CULVERT FLOW CALCULATIONS 1-- I -' I I n ~ ~ I: I -' Storage and Discharge Pond Summary Worksheet Settling Pond Infiltration Pond Emergency Park Storage GRAVEL GALLERY WORKSHEET -NORTH Outflow 162.64 cfs -Storage Volume 109,805 cf 1 L L_ L L WHIPPLE CONSULTING ENGINEERS POND VOLUME CALC SHEET Project: 13-1166 Designer: lPP FLOOD PONDS Volume to Bioswale Outlet Ponds Bottom Squared Area Side sf If STORAGE 61.004 247 *SETTLING 7,172 85 Total 68,176 Pond Bottom Elevation at Drywell 1995.80 1996.80 Pond Pond Drywell Inlet Elevation Elevatior (avg) 1996.80 1997.80 1996.80 1997.80 * Assumes portion of Bioswale to reach a depth of I' but does not include additional volume Volume to Pipe Inlet ._-- Ponds Bottom Squared Pond Pond Pond Area Side Bottom Drywell Inlet Elevation Elevation Elevatiol sf If at Drywell (avg) STORAGE 61.004 247 1995.80 1996.80 2000.24 SETTLING 7,172 85 1996.80 1996.80 2000.24 Total 68,176 *Does not include additional storage provided by Bioswale Emergency Park Storage -. Ponds Bottom Squared Pond Pond Pond Area Side Bottom Drywell Inlet Elevation Elevation ElevatioJ: sf If at Drywell (avg) 1 Rim 1176,1811 420 1 2006.00 1 2007.00 1 201 1.00 1 J :-J :-J ~ IJ --] --j Date: 6/19/2018 11 s, ~ Conic Side Total Conic Side Total Volume Slope Volume te Volume Slope Volume to Rim Volume to Rim to Inlet Volume to Inlet cf cf cf cf cf cf 6 1.004 1,482 62 ,486 122,008 5,928 127,936 0 0 0 7,172 508 7,680 62,486 135,616 Conic Side Total Conic Side *Total Volume Slope Volume te Volume Slope Volume to Rim Volume to Rim to Inlet Volume to Inlet cf cf cf cf cf cf 61,004 1,482 62,486 270,858 29,2 14 300,072 0 0 0 24,672 6,013 30,685 62,486 330,757 Conic Side Total Conic Side *Total Volume Slope Volume te Volume Slope Volume to Rim Volume to Rim to Inlet Volume to Inlet cf cf cf cf cf cf 176,181 1 2,518 1 178,699 1 880,905 1 62,961 1 943,8661 ac-ft = 4.10 21.67 L L ~ L WHIPPLE CONSULTING ENGINEERS GRAVEL GALLERY CALC SHEET 5/15/2018 13-1166 ENGINEER Painted Hills PRD JPP Note: infiltration rates per IPEC Geotechnical Report Dated December 31 ,2013 ---- Gallery CONTACT AREA A B C D E Totals Volume" Porosity Perimeter"Depth Number Length of Galleries 1 246.99 1 280.00 1 280.00 1 280.00 1 280.00 1 100.00 ---- Storage Volume = Sidewall Area= OutFlow = Sidewall Area+ Bottom Area " Infiltration Rate Note: Outflow Assumes a Full Gallery Width Ground Water EL. ft ft ft 246.99 - 10.00 - 10.00 - 10.00 - 10.00 - 10.00 - Gravel Volume Gallery Bott.EL ft cf -244016 -28,000 -28,000 -28,000 -28,000 -10,000 :=-J :::-J . ] ::-l ::-l ~ .~ Gallery Porosity Depth of Gravel Infiltration (Min) ITyp) Rate ft cflcf cfs/sf 10 0.3 1.80E-03 4 0.3 1.80E-03 ------- Storage Perimeter Sidewall Bottom Outflow Volume Area Area cf ft sf sf cfs 73205 988 3,952 61,004 116.92 8,400 580 5,800 0 10.44 8,400 580 5,800 0 10.44 8,400 580 5,800 0 10.44 8,400 580 5,800 0 10.44 3,000 220 2,200 0 3.96 109,805 162.64 "Note: Btm Area = Gallery Area -Contact Area l l I I I J J BIO-FILTRATION CHANNEL WORKSHEET 79 cfs With Channel South of Thorpe 83% of treatment achieved 106 cfs Without Channel South of Thorpe 69% of treatment achieved Open-Channel Hydraulics, Chow (reference) -, J J Bio-filtration Swale Design Based on King County 2005 Surface Water Design Manual (Section 6.2 and 6.3) Modified to model flow of flood water utilizing reference Open Channel Hydraulics, CHOW Design Flow: Qwq = 79.00 cfs With channel south of Thorpe Calculation of swale depth Q = 1.49 A Ro.67So.5 n·1 OR Manning's equation b = Q n (1 49 * y1.67S0.5r1 wq wq . where b OR Qwq y = [Qwq nwq (1.49 * b * SO.5rY6 nwq y S width known: b= 6.00 ft S= 0.010 ftIft nwq = 0.175 y= 5.17 ft Determining design flow velocity: Vwq = QWq / AwQ, max 1.0 fps where Vwq Awq = b*y + Z*i" Awq Z Z= 2 Awq= 111.10 sf Vwq = 0.71 fps = bottom width of swale (ft) ... minimum 2 ft width required, maximum 10ft = water quality design flow (cfs) = Manning's roughness coefficient for vegetal retardance conditions (CHOW) = design flow depth = longitudinal slope (along direction of flow) (ftIft) , slope shall be between 1 %-6%. If less than 1.5%, underdrains must be provided. Slope less than 1 % is considered a "wet biofiltration swale" and must be designed under those guidelines. Slope greater than 6% requires check dams with vertical drops of 12-inches = design flow velocity (fps) = cross-sectional area of flow at design depth (sf) = side slope length per unit height (e.g. for 3:1, Z = 3) Calculate swale length to achieve a minimum hydraulic residence time of 9 minutes (540 seconds): L = 540 * Vwq, minimum swale length is 100 ft L = 383.98 ft Calculation to verify n -value Per Table on page 182 of Open-Channel Hydraulics IVRh =VR In -plot 2.04 0.175 -, Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. --, 1 "I • J -, ., Bioswale @79 cfs Trapezoidal Bottom Width (ft) Side Slopes (z: 1) Total Depth (ft) Invert Elev (ft) Slope (%) N-Value Calculations Compute by: No. Increments Elev (ft) 1007.00 1006.00 \ " = 6.00 = 3.00,3.00 = 6.00 = 1000.00 = 1.00 = 0.175 Q vs Depth = 36 1005.00 \: 1004.00 1003.00 ~ \ .-- \ 1002.00 • 1 I 1001 .00 -..J 1000.00 -" . -.. \ \ I -..J 999.00 1-o 5 10 15 20 Section "V - .- Highlighted Depth (ft) Q (cfs) Area (sqft) Velocity (ft/s) Wetted Perim (ft) Crit Depth, Yc (ft) Top Width (ft) EGL (ft) I -I 'V I V 'V / V J 25 30 35 40 45 Reach (ft) Tuesday, Jun 192018 1J-. f ( O:~r,f;I(fll l 6jl ( f V,J V = 5.17 = 190.65 = 111 .08 = 1.72 = 38.68 = 2.22 \ = 37.00 (;II = 5.21 Depth (ft) 7.00 6.00 5.00 4.00 3.00 2.00 1.00 0.00 -1.00 50 55 -, -', -) 1- Bio-filtration Swale Design Based on King County 2005 Surface Water Design Manual (Section 6.2 and 6.3) Modified to model flow of flood water utilizing reference Open Channel Hydraulics, CHOW Design Flow: 106.00 cfs Without channel south of Thorpe Calculation of swale depth Q = 1.49 A Ro.67So.5 n-1 OR Manning's equation b = Q n (1 49 * y1.67S0.5)-1 wq wq . where OR width known: b = 6.00 ft S = 0.010 ftlft nwq = 0.130 y = 5.16 ft Determining design flow velocity: Vwq = QWq / Awq, max 1.0 fps Awq = b*y + z*1 Z= 3 where Awq= 123.80 sf VWq = 0.86 fps b Qwq nwq y S Vwq Awq Z = = = = = = = bottom width of swale (ft) ... minimum 2 ft width required, maximum 10ft water quality design flow (cfs) Manning's roughness coefficient for vegetal retardance conditions (CHOW) design flow depth longitudinal slope (along direction of flow) (ft/ft), slope shall be between 1 %-6%. If less than 1.5%, underdrains must be provided. Slope less than 1 % is considered a "wet biofiltration swale" and must be designed under those guidelines. Slope greater than 6% requires check dams with vertical drops of 12-inches design flow velocity (fps) cross-sectional area of flow at design depth (sf) side slope length per unit height (e.g. for 3:1, Z = 3) Calculate swale length to achieve a minimum hydraulic residence time of 9 minutes (540 seconds): L = 540 * Vwq, minimum swale length is 100 ft L = 462.36 ft Per Table on page 182 of Open-Channel Hydraulics IVRh =VR In -plot 2.74 0.175 ., Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Tuesday, Jul17 2018 Bioswale @ 106 cfs Trapezoidal Highlighted Bottom Width (ft) = 6.00 Depth (ft) = 5.16 ~ Side Slopes (z: 1) = 3.00,3.00 Q (cfs) = 255.89 -I Total Depth (ft) = 6 .00 Area (sqft) = 110.84 Invert Elev (ft) = 1000.00 Velocity (ft/s) = 2.31 -, Slope (%) = 1.00 Wetted Perim (ft) = 38 .63 I -, N-Value = 0.130 Crit Depth, Yc (ft) = 2.57 Top Width (ft) = 36.96 'I Calculations EGL (ft) = 5.24 I I Compute by: Q vs Depth . J No. Increments = 50 -, -, Elev (ft) Section Depth (ft) 1007.00 -,----,----.,------,----,----,------.----.---__ ,----,----r----,--7.00 1006.00 6.00 f\ ·V ... .-.-~ 1005.00 ~ I 5.00 , \ I - --.- .-1 . -~. - ~ ---- , 1004.00 .1{-4.00 \ -~ ---- ....J . ----/. _. . -_. ---. 1003.00 \. 3.00 V . . . .....J f\ _. -. 1002.00 \ 2.00 I . - _.J 1001 .00 1.00 \ ~ V 1000.00 J 0.00 J 999.00 -1 .00 1-0 5 10 15 20 25 30 35 40 45 50 55 ...J Reach (ft) OPEN-CHANNEL HYDRAULICS VEN TE CHOW, Ph.D. Professor of Hydraulic Engineering Universtty of Illinois McGRAW-HILL BOOK COMPANY New York Toronto London 1959 184 TABLE 7w 5. GUIDE IN SELECTION OF VEGETAL RETARDANCE* Stand Average length of grass, in. Degree of retardance >30 A Very high 11-24 B High Good 6-10 C Moderate 2-6 D Low <2 E Very low >30 B High 11-24 C Moderate Fair 6-10 D Low 2-6 D Low <2 E Very low * U.S. Soil Conservation Service [41]. 7 -18. The Permissible Velocity. The permissible velocity of flow in a grassed channel is the velocity that will prevent severe erosion in the channel for a reasonable length of time. Permissible velocities for differ- ent vegetal covers, channel slopes, and soil conditions, recommended on the basis of investigation by the Soil Conservation Service, are shown in Table 7-6. 7 -19. Selection of Grass. The selection of grass for the channel lining depends mainly on the climate and soil in which the plant will grow anci survive under the given conditions. From the hydraulic viewpoint, stability and other factors should also be considered. In general, a higher discharge requires a stronger or better lining. On steep slopes, bunch grasses, such as alfalfa, lespedeza, and kudzu, will develop channel- ing of the flow and, hence, are unsatisfactory for lining. For slopes greater than 5 %, only fine and uniformly distributed sod-forming grasses, such as Bermuda grass, Kentucky bluegrass, and smooth brome, are recommended for lining where the main flow occurs. Because of the objectionable spreading nature of sod-forming grasses, the top portion of the sides and the berm may be planted with grasses that do not spread easily, such as weeping love grass. For fast establishment of the lining, Bermuda grass and weeping love grass are recommended. Sometimes;. annuals are used as temporary protection until permanent covers by native grasses are established. Silt deposition in channels may be con- trolled by lining with bunch grasses, which will develop channeled flow, increase velocity, and thus reduce silting. 7 -20. Procedure of Design. Mter the kind of grass for channel lining is selected, the degree of retardance can be determined from the condition of the stem length and the density of growth. During the period of DESIGN OF CHANNELS FOR UNIFORM FLOW 185 est[1blishment, the grass will grow and the channel will be stabilized under a condition of low degree of retardance. The channel will not reach its maximum capacity until the grass cover is fully developed and well established. Therefore, it is suggested that the hydraulic design of a 151!assed channel consist of two stages. The first stage (A) is to design the channel for staQility, that is, to determine the channel dimensions uncleI' the condition of a lower degree of retardance. The second stage TABLE 7-6. PERMISSIBLE VELOCITIES FOR CHANNELS LINED WITH GRASS* Cover Bermuda grass Buffalo grass, Kentucky bluegrass, . smooth brome, blue grama Grass mixture Lespedeza sericea, weeping love Slope range, % 0-5 5-10 >10 0-5 5-10 >10 0-5 5-10 Permissible velocity, fps Erosion-resistant soils 8 7 6 7 6 5 5 4 Easily eroded soils 6 5 4 5 4 3 4 3 Do not use on slopes steeper than 10 % 0-5 3 .5 2.5 gl'ass, ischaemum (yellow blue-Do not use on slopes, steeper than 5 %, except for s't,em), kudzu, alfalfa, crabgrass side slopes in a combination channel Annuals-used on mild slopes qr as temporary protection until per- manent covers are established, common lespedeza, Sudan grass 0-5 3 .5 2.5 Use on slopes steeper than 5 % is not recom- mended REMARKS. The values apply to average, uniform stands of each type of cover. rJse velocities exceeding 5 fps only where good covers and proper maintenance can be obtained. ,. U.S. Soil Conservation Service [41]. (B) is to review the design for maximum capacity, that is, to determine the increase In depth of flow necessary to maintain a maximum capacity under the condition of a higher degree of retardance.For instance, if c@mmon lespedeza is selected as the grass for lining, the common lespedeza 0f low vegetal retardance (green, average length 4.5 in.) is used for the fh:st stage in design. Then, in the second stage, the common lespedeza 0f moderate vegetal retardance (green, uncut, average length 11 in.) sh0uld be used. Finally, a proper freeboard is added to the computed -L --l ,---l 182 .8 i ,6 .5 .4 .3 o .11 .~-t.. .2 ~~ ,. i '/ I ' ,-" f- s:: 0.\) .1 .08 .06 .015 .04 .03 . 002 .& . 8 .S -l ---...- --~ ,-l --L _' _ J __J__ 1.___ 1 _J _J __ 1 o f{1I t{ilJlI/lV~l-/If 0 ~II.CC.~ ( C flc7w UNIFORM FLOW ----- ~---~----.... -. o~o. ..... , ODD .::: :~ ----~ ----V~ " .- ~ ---~ V ~EEPING LOVEGRA§§ ----.. -. '1-GREEN, 2ND SEASON I ,._--'-,-------~ /. AVE. LENGTH 30" ( ~~ / I ------.------I ,~. ~ I / ~ .. I I I / "-" ... ~ I AEM~ ......... ..... ISC .. ..... GRf EN, 1ST SEASe N 0-r_ D .. AVE . LENGTH 36' / / AVERAGE (A) - .2 .3 .4.5.6 .8 1 S 2 -l1{3 4 G 6 e 10 V -1-. (a) Curves for A or ver R h vegetal retardance . 20 ~ --GREEN. AVE LENGTH 12'" J I I I ~ I I if l - I Geotechnical Reports Triangle Pond Infiltration (Storage Area 6) IPEC Proposed Stormwater Pond dated October 14, 2014 North Pond Location Boring IPEC Supplemental Geotechnical Evaluation dated April 19, 2016 Pavement Design (Public Roads) IPEC Geotechnical Evaluation -Proposed Street Improvements dated June 26, 2017 Full-Scale Drywell Testing IPEC Full-Scale Drywell Testing dated August 21,2017 IPEC Addendum to Full-Scale Drywell Testing dated August 22, 2017 Mounding Analysis IPEC Mounding Analysis dated August 22, 2017 J October 14,2014 Project No. 14-086 NAIBlack c/o Mr. Bryan Walker 107 South Howard Suite 500 Spokane, W A 99201 IPEC Inland Pacific Engineering Company Geotechnical Engineering and Consulting Re: Geotechnical Evaluation Proposed Stormwater Pond Parcel No. 45343.9052 Spokane Valley, W A Dear Mr. Walker: As you authorized, we have completed a geotechnical evaluation for geotechnical evaluation at the above-referenced site in Spokane Valley, Washington. The purpose of our services is to evaluate the subsurface soil and groundwater conditions relative to use as a stormwater management facility as part of the Painted Hills golf course property stormwater management system. This report summarizes the results of our site investigation, engineering analyses and recommendations. PROJECT DESCRIPTION We understand that the proposed project may consist of a residential development. The site consists of 91 acres currently developed as a golf course. Stormwater runoff will be treated using drywells and/or gravel galleries for subsurface infiltration. These type of facilities will also be used to manage potential floodwaters, if needed. To account for stormwater runoff volumes from the unnamed tributary along State Highway 27, you propose to use this parcel as a stormwater pond with drywells for subsurface infiltration. P.O. Box 1566, Veradale, WA 99037 Phrmp 'ino_ ?nO_h?h? ... J l Geotechnical Evaluation Proposed Stormwater Pond Spokane County, WA Inland Pacific Engineering Company AVAILABLE INFORMATION Project No. 14-086 Parcel No. 45343.9052 October 14,2014 Page 2 We were provided a conceptual site plan for the project by Whipple Consulting Engineers, Inc. (WCE). This plan showed the proposed pond limits, proposed and existing ground surface elevation contours, and property lines. This plan was prepared by WCE and was not dated . FIELD EVALUATION Procedures A geotechnical engineer from Inland Pacific Engineering Company (lPEC) observed the excavation of four test pits at the site. The test pits were excavated on October 1,2014 using a rubber-tired backhoe operated by an independent firm working under subcontract to IPEC. The geotechnical engineer from IPEC observed the test pit excavations and logged the surface and subsurface conditions. Ground surface elevations at the test pits were interpolated from the contours shown on the site plan. The soils encountered in the test pits were visually and manually classified in the field by our field personnel in accordance with ASTM D 2488, "Description and Identification of Soils (Visual- Manual Procedures)". The samples were returned to our facility for review of the classification by a geotechnical engineer and laboratory testing. Soils Encountered The test pist encountered glacially deposited silty sand at the surface overlying poorly graded sands to the termination depths of the test pits. Groundwater was not encountered in the test pits during or after excavation. Well log data in the vicinity of the site indicate that groundwater levels range from approximately 90 to 100 feet. Geologic maps indicate the soils in this area consist primarily of glacially deposited sands and gravels. According to the Soil Survey of Spokane County, the site soils are classified as Urban land-Springdale, disturbed complex. These soils are described as somewhat excessively drained soils that formed in sandy and gravelly glaciofluvial deposits with minor amounts of volcanic ash and loess in the upper part. The native soils exposed in the test pits were consistent with the NRCS data. Laboratory Testing We performed grain size analysis tests on samples obtained from the test pits. The tests were performed in accordance with ASTM Method of Test D 6913. The results of the tests performed are attached to this report. I l. J Geotechnical Evaluation Proposed Stormwater Pond Spokane County, WA Inland Pacific Engineering Company Project No. 14-086 Parcel No. 45343.9052 October 14, 2014 Page 3 ANALYSIS AND RECOMMENDATIONS Stormwater Recommendations Based on the data obtained from the test pits, field permeability test, and laboratory tests performed, it is our opinion that swales and drywells would be suitable for infiltration of stormwater. We estimated a design outflow rate for drywells using the results of the laboratory tests and the procedures described in the SRSM manual, Appendix 4A (Spokane 200 Method). The following table summarizes the results of the analysis. Normalized Recommended Design Test Depth USCS Percent Outflow Drywell Outflow Rate Pit (feet) Classification Fines Rate (cfs) (cfs/ft) Type A TypeB TP-1 10-12 SP 1.0 0.5 0.3 1.0 TP-2 10-12 SP 1.5 0.5 0.3 1.0 TP-3 10 -12 SP 1.4 0.5 0.3 1.0 TP-4 10-12 SP 1.6 0.5 0.3 1.0 These recommended design outflow rates include a safety factor of 1.3 as required by the SRSM. REMARKS This report is for the exclusive use of the addressee and the copied parties to use in design of the proposed project and to prepare construction documents. In the absence of our written approval, we make no representations and assume no responsibility to other parties regarding this report. The data, analyses, and recommendations may not be appropriate for other structures or purposes. We recommend that parties contemplating other structures or purposes contact us. Services performed by the geotechnical engineers for this project have been conducted in a manner consistent with that level of care ordinarily exercised by members of the profession currently practicing in this area under similar budget and time restraints. No warranty, expressed or implied, is intended or made. l I .J , J J J J Geotechnical Evaluation Proposed Stormwater Pond Spokane County, WA Inland Pacific Engineering Company GENERAL REMARKS Project No. 14-086 Parcel No. 45343.9052 October 14,2014 Page 4 It has been a pleasure being of service to you for this project. If you have any questions or need additional information, please do not hesitate to call me at (509) 209-6262 at your convenience. Sincerely, Inland Pacific Engineering Company 4L Paul T. Nelson, P.E. Principal Engineer Attachments: Figure 1, Site Location Map Figure 2, NRCS Map Figure 3, Test Pit Location Map Logs of Test Pits TP-l through TP-4 Descriptive Terminology Laboratory Test Results FIGUREl l l l J J Site Location Map IPEe Project No. 14-086 Proposed Stormwater Pond October 9, 2014 Inb.nd Pacific EDgineering Company Parcel No . 45343.9052 J Geotechnical EDgineering and Conrulting Spokane County, WA l . J -I I IPEe I Inland Pacific Engineering Company Geotechnical Engineering and Consulting FIGURE 2 NRCSMap Proiect No. 14-086 Proposed Stormwater Pond October 9, 2014 Parcel No. 45343.9052 Spokane County, WA 11 l I --' IPEe Inland Pacific Engineering Company Geotechnical Engineering and Consulting FIGURE 3 ", -----.. ' -"'---",," ~~~\~.,..----",\ Test Pit Location Map_ Project No. 14-086 Proposed Storrnwater Pond Parcel No. 45343.9052 Spokane County, W A ') / / / / October 9, 2014 n l J _...1 LOG OF TEST PIT PROJECT: 14-086 Geotechnical Evaluation Proposed Stormwater Pond Parcel No. 45343.9052 Spokane County, WA ELEV. DEPTH ASTM 02487 DESCRIPTION OF MATERIALS 1994.5 0.0 Symbol Inland Pacific :Engin~elin.ll Company Geotechnical Engineering and Consulting TEST PIT: TP-l LOCATION: See Test Pit Location Map DATE: 10/1/14 ISCALE: 1"=2' WL TESTS OR NOTES SM SILTY SAND WITH GRAVEL, fine to coarse grained, brown, moist. 1993.5 1.0 'Glacial Outwash) POORLY GRADED SAND WITH GRAVEL, medium to coarse grained, with Cobbles, brown, moist. (Glacial Outwash) SP End of test pit. 1979.5 15 .0 Groundwater not encountered. Test pit immediately backfilled. l J _J I -' J LOG OF TEST PIT Jl..Jl.. ..L.J '-.../ Inland Pacific Engi.n~erin.!l Company Geotechnical Engineering and Conrulting PROJECT: 14-086 TEST PIT: TP-2 Geotechnical Evaluation Proposed Stormwater Pond Parcel No. 45343.9052 Spokane County, WA LOCATION: DATE: 10/1/14 ELEV. DEPTH ASTM 02487 DESCRIPTION OF MATERIALS 1994.5 0.0 Symbol 1993.0 1.5 1979.5 15.0 -- SILTY SAND WITH GRAVEL, fine to coarse grained, brown, moist. SM (Glacial Outwash) SP POORLY GRADED SAND WITH GRAVEL, medium to coarse grained, with Cobbles, brown, moist. (Glacial Outwash) End of test pit. Groundwater not encountered. Test pit immediately backfilled. WL See Test Pit Location Map ISCALE: 1"=2' TESTS OR NOTES ------I ! n I --., J LU~ Ut-I t~ I fill Inland Pa rifle :Engine-e:ri:nl! Comll any G@otechnical Engineering and Consulting PROJECT: 14-086 TEST PIT: Geotechnical Evaluation Proposed Stormwater Pond Parcel No. 45343.9052 Spokane County, WA LOCATION: DATE: 10/1/14 ELEV. DEPTH ASTM 02487 DESCRIPTION OF MATERIALS 1995 0.0 Symbol 1994 1.0 SILTY SAND WITH GRAVELl fine to coarse grained, brown, SM moist. SP I(GlaciaIOutwash) POORLY GRADED SAND WITH GRAVELl medium to coarse grained, with Cobbles, brown, moist. (Glacial Outwash) End of test pit. i----=-'19~8~0'_+_...:.1=5"'-"'.O'_+_-____I Groundwater not encountered. Test pit immediately backfilled. WL TP-3 See Test Pit Location Map ISCALE: 1"=2' TESTS OR NOTES l I -) ---' I _I LOG OF TEST PIT PROJECT: 14-086 Geotechnical Evaluation Proposed Stormwater Pond Parcel No. 45343.9052 Spokane County, WA ELEV. DEPTH ASTM 02487 DESCRIPTION OF MATERIALS 1996 0.0 Symbol lLlI. .J-I '-" Inland Pacific ::Engine-eIin.g Camp any Geotechnical Engineering and Conrulting TEST PIT: TP-4 LOCATION: See Test Pit Location Map DATE: 10/1/14 -,SCALE: 1"=2' WL TESTS OR NOTES SILTY SAND WITH GRAVEL, fine to coarse grained, brown, SM moist. 1995 1.0 I{GlaciaIOutwash) POORLY GRADED SAND WITH GRAVEL,medium to coarse grained, with Cobbles, brown, moist. (Glacial Outwash) SP End of test pit. 1981 15.0 Groundwater not encountered. Test pit immediately backfilled. l - j I -, IPE e In12nd Pacific Engineering Cornp=y Geotechnical Engineering and Con"wting RELATIVE DENSITY OR CONSISTENCY VERSUS SPT N-VALVE COARSE-GRAINED SOILS FINE-GRAINED SOILS DENSITY N(BLOWSfFT) CONSISTENCY N(BLOWSIFf) Very Loose 0-4 Very Soft 0-1 Loose 4 -10 Soft 2-3 Medium-Dense 11 -30 Rather Soft 4-5 Medium 6-8 Dense 31 -50 Rather Stiff 9 -12 Stiff 13 -16 Very Dense > 50 Very Stiff 17 -30 Hard > 30 USCS SOIL CLASSIFICATION MAJOR DIVISIONS GROUP DESCRIPTIONS Coarse-Gravel and Gravel GW Well Graded Gravel Grained GravelIy Soils twilhllltlC:(lfn1,lIinu ) GP Poorly Graded Gravel Soils <50% coarse fraction Gravel GM Silty Gravel passes #4 sieve (with >12'k finl!s) GC Clayey Gravel <50% Sandy and Sand SW Well Graded Sand passes #200 Sandy Soils \v'IIh litllC:llCnl)£inn ) SP Poorly Graded Sand sieve >50% coarse fraction Sand SM Silty Sand passes #4 sieve (with >12';;' fin\!s) SC Clayey Sand Fine-ML Silt Grained Silt and Clay CL Lean Clay Soils Liquid Limit < 50 OL Organic Silt and Clay (low plasticity) >50% MH Inorganic Silt passes #200 Salt and Clay CH Fat Clay sieve Liquid Limit> 50 OH Organic Clay and Silt (med to high plasticity) Highly Organic Soils PT Peat IMuck MODIFIERS MOISTURE CONTENT DESCRIPTION RANGE DESCRIPTION FIELD OBSERVATION Occasional <5% Dry Absence of moisture, dusty, dry to the touch Trace 5% -12% Moist Dry of optimum moisture content With >12% Wet Wet of optimum moisture content MAJOR DIVISIONS WITH GRAIN SIZE SIEVE SIZE 12" 3" 3/4" 4 \0 40 200 GRAIN SIZE (INCHES) 12 3 0.75 0.19 0.079 0.0171 0.0029 Boulders Cobbles Gravel Sand Silt and Clay Coarse I Fine Coarse IMediumlFine L L L -..: L L J J J 3" 3/4" #4 #10 #20 #40 #100 #200 100.0 I I I I I "" ~K ; ; I ! ! ! 0 I ! i , ~ ~-90.0 .-1-. ~ -...:.... 1-----. 1---I-1--1--10 , 80.0 Ti 20 I t ! I i i I: t i p P 70.0 IIII T 30 e e ; I ! I I ! I r r t I ~ ; i I t C c 60.0 e II! ; I I i 40 e t 1 \ ' I i 1 I n n ! 1 I I t 50.0 -ii ' I ! 50 1 11 I \ I R p I I . . ! : i I e a I t s 40.0 I: II , I 60 I j a i I 1 s 1\ j I i Ii I I i " j I ; 30.0 ; 1-.-n n ''\ I I I 70 1 j e 9 , I , I d : ; ! 20.0 , , 80 ! I '1 \ I I I I I I i , I I 1 I I ; I Ii i 1 10.0 I -.-, I '\1 I 90 ! 1 1 ! I I ! i ! I 0.0 , 100 100 10 1 0.1 0.D1 0.001 GRAIN SIZE (mm) UNIFIED SOIL COARSE FINE COARSE MEDIUM FINE CLASSIFICATION FINES SYSTEM GRAVEL GRAVEL SAND SAND SAND Sample Identification: Sample Description: Lab '\ No. L14-039 SP Poorly Graded Sand with Gravel L14-039 .J IPEe Project: 40th Avenue Stormwater GRAIN SIZE Location: TP-1 @ 10-12' Inland Pacific Engineering Company REPORT Geot~chnica1 Engineering and Consulting Job No.: Dale: P.O Box 1566, Veradale, WA 99037 (509) 209-6262 14-086 10/1/2014 L L UNIFIED SOIL CLASSIFICATION SYSTEM L-J L COARSE GRAVEL Sample Identification: L14-040 l - L #4 I' I -/-H-T-- II! 1 #10 #20 1 I -+----~ ., ~ J #40 #100 #200 I I I' ; i I k~-l-t -t --,--.- I H -+-+--1--+ Tn ~ I i 1 I ++++++-+~--- I ~I -III I I I II I ! II III I I I I I II I I I I I I FINE GRAVEL fT ~ I 1\1 11 \~', I , I i I Ii Ii \I ,I 1/ I ~ Ii 1 I COARSE SAND [---I I "- If MEDIUM SAND I ! Ii I! I II II II Ii 1 1111 II I I I: ILl I I I' GRAIN SIZE (mm) FINE SAND i , I:· I : I -Il l J j 0.1 -r FINES Sample Description: SP Poorly Graded Sand with Gravel 0.01 Lab No. !PEe GRAIN SIZE REPORT Project: 40th Avenue Stormwater Inl:md P:acific Engineering Comp:my Geotechnical Engineering and Consulting P.D Box 1566, Veradale, WA 99037 (509) 209-6262 Location: TP-2 @ 10-12' Job No.: Date: 14-086 L 14-040 10/1/2014 L 1_ l_ 3" 3/4" I I 100.0 I'! IY ! r ~ , ~I I I i 90.0 ' -t -----r "-i I i J ; 80.0 P 70.0 I e I I C 60.0 e n t 50.0 P a 40.0 5 I 5 n 30.0 I I 9 ! I 20.0 Ii T . I I ; 10.0 ~i -- ! I I I ' I 0.0 100 10 UNIFIED SOIL COARSE FINE CLASSIFICATION GRAVEL SYSTEM GRAVEL Sample Identification: L14-041 IPE e InI:md P"cific Engineering Company Geotechnical Engineering:md Consulting P.O Box 1566, Veradale, WA 99037 (509) 209-6262 #4 I I, . i r-.., : i r\ ~ \ 1 I : I I , I ' , I : . .' I I I II I ~ ~ J ~J J L J J #10 #20 #40 #100 #200 I I I J " , I , t -i-I-mtt H ~f I 0 . I ~II ! -+f--!--+ ---I 10 I , ! ; I + I I I I I I I I 20 I , I I I I I I ; , I ! I ii , i I p , 1 I 30 e I II I 1, I , I I I I i' , I: ' I I I I I \ ! Ii • 1 C 1 , \ I 1/ : :, ' I I I ----40 e 1 ' 1 n ' I I Ii j I I I : t I \1 !I ' , 50 i I R , ! I I e : --t ~ I 60 I ! I a I I ' . , , I I i I 1 , , ; . , n , \ ! ' , 70 e ' I ; r-l--I ! i d I . , + \! i I I --: --80 I , , ! I ! I I I i 1 ! j I , 'i 90 I I ~r--1 I I I I I 1 -~H--4-1 i i I I i 1 100 0.1 0.01 0.001 GRAIN SIZE (mm) MEDIUM FINE FINES SAND SAND Sample Description: SP Poorly Graded Sand with Gravel [ Lab ] No. L14-041 GRAIN SIZE REPORT Project: 40th Avenue Stormwater Location: TP-3 @ 10-12' Job No.: Date: 14-086 10/1/2014 --.J L J 3" 3/4" #4 #10 #20 #40 #100 #200 100.0 . I I I 1 1 qr! ~~ I ! I I I I' 0 III \ i I 1 ' 90.0 --~-,\I--f-,-~. ~ , ~ -+ -t -. -----10 I I I I, I I " I i :1 ' i I 80.0 +T :. +t -I I -t--H-I-+-+--l-+-~'-+---+-I+1H--f-+'-, .-. 20 p I ~~ I I: ' I: I , i! p 70.0 r\ I I . -30 e e ! 'i' I ! I I , I I , I c I \ i i i I c 60.0 , I '\ ' , I 40 e e I ! i 'I n n ' I ; 1 ~ I t 1\ ! iii I I I 50.0 ! I \ . I ! -H1-H1-+--+1---+---I1'---+-t, ----50 p i, ' I I I; ! ,! R a i II I I i i ; I I I i I ~ s 40.0 I I !, \ i ' I' ! I t -60 a S 'I I 'I I. I ' 1 I ! ! I i . I ' I ' , I I j I : , i : n n 30.0 I' 'I I I \ I i ii' I:: -+-,, -+,---+H--H-+-+--+--+--'~ 70 e 9 . I I 'I\'!! d 'i ' :,' 1 1\ II ' Ii. ; ! I 20.0 ! --:'. \ I '!'! ! ' -+,--+----1 80 . i 'I ' I , I I i I I . ; , , ' , ,Ii i : i i i I' 10.0 ! I .. --_.-90 I ! Ii; t~,_1 I I I' /: I 0.0 Ii i " 100 100 10 0.1 0.01 0.001 GRAIN SIZE (mm) UNIFIED SOIL CLASSIFICATION COARSE FINE COARSE MEDIUM FINE FINES SYSTEM GRAVEL GRAVEL SAND SAND SAND Sample Identification: Sample Description: Lab No. L 14-042 SP Poorly Graded Sand with Gravel L 14-042 ' IPE e GRAIN SIZE proje~t: 40th Avenue Stormwater Location: I InI:md Pacific Engineering Comp:r.ny R E PO RT TP-4 @ 10-12 Geotechnical Engineering and Consultine t-J""'o""'b-:-N""'o-.: ----------..O=-a-t-e:------ P.D Box 1566, Veradale, WA 99037 (509) 209-6262 .____ 14-086 10/1/2914 I J April 19, 2016 Project No. 16-249 NAI Black c/o Mr. Bryan Walker 107 South Howard Suite 500 Spokane, W A 99201 Inland Pacific Engineering Company Geotec1mical Engineering and Consulting Re: Supplemental Geotechnical Evaluation Painted Hills Golf Course Property 4403 South Dishman-Mica Road Spokane Valley, WA Dear Mr. Walker: As you authorized, we have completed the supplemental geotechnical evaluation for the Painted Hills Golf Course property at the above-referenced site in Spokane Valley, Washington. The purpose of the supplemental evaluation is to provide additional soil and groundwater data to address concerns ofthe City of Spokane Valley. This report summarizes the results of our field investigation, laboratory testing, engineering analyses, and our opinions and recommendations for stormwater management. PROJECT DESCRIPTION We understand that the proposed proj ect may consist of a residential development. The site consists of91 acres currently developed as a golf course. Stormwater runoff will be treated using drywells and/or gravel galleries for subsurface infiltration. These type of facilities will also be used to manage potential floodwaters, if needed. This supplemental evaluation is intended to provide additional subsurface data at the north end ofthe site to assist in identifying areas where subsurface infiltration of stormwater may be feasible due to the presence of suitable soils at depth. P.o . Box 1566, Veradale, WA 99037 Phone 509-209-6262 -I I ~ , I _ ) -' Supplemental Geotechnical Evaluation Painted Hills Golf Course Property Spokane Valley, WA Inland Pacific Engineering Company AVAILABLE INFORMATION Project No. 16-249 Parcel No. 45344.9\08 April 19,2016 Page 2 We were provided a topographic survey for the project site by Whipple Consulting Engineers, Inc. (WCE). This topographic survey showed the existing roadways, existing structures, property lines, and existing ground surface elevation contours. This plan was prepared by WCE and was dated November 7,2013. The site was used as a golf course prior to our evaluation. The site is relatively level with some elevated golf greens and excavated areas for water hazards. The site is primarily grass-covered with scattered trees along the fairways and pine trees in the undeveloped area to the northwest. The clubhouse building is present at the southwest comer. In addition, we performed a preliminary geotechnical evaluation for the property in December 2013. The results of that evaluation, along with our opinions and recommendations, are summarized in our Preliminary Geotechnical Evaluation dated December 31,2013. We also performed a geotechnical evaluation for certification of the existing levee along Chester Creek in April 2014. The results of that evaluation are summarized in our Geotechnical Evaluation report dated February 12,2015. Lastly, we performed a geotechnical evaluation in July 2015 consisting often 50-foot borings in the south half of the property. The results ofthat evaluation are summarized in our Geotechnical Evaluation Phase 2 report dated July 23,2015. FIELD EVALUATION Procedures A geotechnical engineer from Inland Pacific Engineering Company (IPEC) observed the drilling of three penetration test borings at the site. The borings were drilled between March 17 and 19,2016 using a truck-mounted drill operated by an independent firm working under subcontract to IPEC. A geotechnical engineer or engineering assistant from IPEC observed the borings and logged the surface and subsurface conditions. After we logged the borings, they were abandoned in accordance with state requirements. Ground surface elevations at the borings were provided by WCE. The soils encountered in the borings were visually and manually classified in the field by our field personnel in accordance with ASTM D 2488, "Description and Identification of Soils (Visual- Manual Procedures)". The samples were returned to our facility for review of the classification by a geotechnical engineer and laboratory testing. ", -, , J J -' Supplemental Geotechnical Evaluation Painted Hills Golf Course Property Spokane Valley, WA Inland Pacific Engineering Company Soils Encountered Project No. 16-249 Parcel No. 45344.9108 April 19,2016 Page 3 In general, the borings encountered 2 feet of topsoil at the surface. Below the topsoil, the borings generally encountered glacially-deposited silty to clayey sands and/or gravels overlying poorly graded sands to tenmnation depths of the borings. The clayey sands and gravels were generally encountered in the upper 12 to 18 feet. Penetration resistances in the sands and gravels ranged from 15 to 90 blows per foot (BPF) and averaged 37 BPF, indicating that these soils were medium dense to very dense, but were typically dense. Geologic maps indicate the soils in this area consist primarily of alluvial and/or glacially deposited silts, clays, sands, and gravels. According to the Soil Survey of Spokane County, the site soils are classified by the Natural Resource Conservation Service (NRCS) as Hardesty ashy silt loam, Narcisse silt loam, Endoaquolls and Fluvaquents, Phoebe ashy sandy loam, and Urban land-Springdale disturbed complex. The native soils encountered in the borings were consistent with the NRCS data. Groundwater was encountered in Boring B-2 at a depth of71 feet. This depth corresponds to an elevation of 1934.6. Groundwater was not encountered in the remaining borings. The observed water levels further indicates that groundwater levels drop generally from south to north with higher levels near Chester Creek. Fluctuations in the groundwater level may occur due to rainfall, flooding, irrigation, spring thaw and other seasonal and annual factors not evident at the time the observations were made. ANALYSIS, OPINIONS, AND RECOMMENDATIONS Based on the data obtained from the recent and previous borings, previous test pits, field permeability tests, and laboratory tests performed, it is our opinion that subsurface infiltration of stormwater is feasible. The most promising layers are the glacial sands and gravels. These soils would be suitable for infiltration using standard drywells. We will perform a mounding analysis for the drywells after the proposed full-scale drywell test is completed to assess down-gradient impacts REMARKS This report is for the exclusive use of the addressee and the copied parties to use in design of the proposed project and to prepare construction documents. In the absence of our written approval, we make no representations and assume no responsibility to other parties regarding this report. The data, analyses, and recommendations may not be appropriate for other structures or purposes. We recommend that parties contemplating other structures or purposes contact us. ....J I j Suppkml!l1tal G,:oh::chnical Evaluation Painted Hills Golf Course Property Spokane Valky, \VA [nland Pacific Engineering Company Projectl\o. 16-249 Parcel No. 45344.9108 April 19,2016 Page 4 Services perfomled by the geotechnical engineers for this project have been conducted in a manner consistent \\,ith that level of care ordinarily exercised by members of the profession cun-emly practicing in tlus area under similar budget and time restraints. No wan-anty, expressed or implied, is intended or made. GENERAL REMARKS It has been a pleasure being of service to you for this project. If you have any questions or need additional infonnation, please do not hesitate to call me at (509) 209-6262 at your convenience. Sincerely, Paul T. Nelson, P.E. Principal Engineer Attachments: Figure 1, Site Location Map Figure 2, NRCS Map Figure 3, Boring Location Map Logs of Borings B-1 through B-3 Descriptive Terminology Laboratory Test Results FIGURE 1 --' Site Location Map IPEC: Project No. 16-249 Painted Hills Golf Course April 19,2016 Inland Pacific Engineering Company 4403 South Dishman-Mica Road Geotechnical Engineering and Consulting Spokane County, W A FIGURE 2 l J NRCSMap IPEC Project No. 16-249 Painted Hills Golf Course April 19, 2016 Inland Pacific Engineering Company 4403 South Dishman-Mica Road Geoteclmical Engineering and Consulting Spokane County, WA --, I I '-' l ., I , I FIGURE 3 --1 -------------_I~~::~~~~~:1 , \ , .-.\. -, I , I , " -', I , I , " -i ..... ~iE:J---,~------------------------,...... . I------·-".:~i~-'~=+ '" '; , ,) Boring Location Map IPEC: Project No. 16-249 Painted Hills Golf Course Inland Pacific Engineering Company 4403 South Dishman-Mica Road Geotechnical Engineering and Consulting Spokane County, W A , ,-, '.\.1,' : , , , April 19, 2016 'I 1 l I --J ~ -' ..., n. (!) ...J ;!: Z w ::;; w ...J n. n. :::l (/) (/) ...J ...J I 0 w f-z ;;: n. en .,. N <0 ;:: z (!i :::J ..: f-z W ::;; W ...J n. n. :::l (/) (/) ...J ...J I 0 W f-Z « n. en .,. N <0 ;;; f-() W ..., 0 a: n. <0 0 N _I (/) f-() w (3 a: n. () w n. CLIENT NAI Black Inland Pacific Engineering Company 3012 North Sullivan Road, Suite C Spokane Valley, WA 99216 Telephone: 509-209-6262 Fax: 509-290-5734 BORING NUMBER B-1 PAGE 1 OF 2 PROJECTNUMBER_1~6~-2~4~9 __________________________ _ PROJECT NAME Painted Hills Supplemental PROJECT LOCATION 4403 South Dishman-Mica Road DATE STARTED --'3"'-/1.:....:7..:..../1'-=6'--____ _ COMPLETED ....;3=/..:..;17:..:..1-'-'16=---____ _ HOLE SIZE ....;8:::...;'-!in=ch.:..:e=s ______ _ DRILLING CONTRACTOR Johnson Exploration Drilling GROUND ELEVATION 2005.9 ft GROUND WATER LEVELS: DRILLING METHOD --'H'-"o"-"II""ow.:..:....=S:..:.;te::.:..m"--'-'A=.;u9=e:.:...r __________________ _ AT TIME OF DRILLING _-_--..:..N-"=o~t ~enC!.::c'-"o-""un'-"t""'er'-"'e.::=..d ______________ _ LOGGED BY -'P'-'R.:.cF __________ _ CHECKED BY -'P.....;T:..:..N=--____ __ AT END OF DRILLING _---'-N'-"o~t ~en-"'c'-"o""unC!.::t~er_"'e.::=..d ______________ _ NOTES W 0.. I >-0:: I-W I-~ WCIl 0..<1:: --J2 TESTS w~ 0 o..::::l 2Z <C en 0 ----L-[>(I ss r--1Q-[XI SS r-1L Xl ss AFTER DRILLING --Not encountered ~ u:i Ie> cj u:i 0..0 ~--J :j e> MATERIAL DESCRIPTION (SM) SILTY SAND, fine to medium grained, with roots, dark brown, moist. ),1 /-(: :":\ 1/. ~;,,;, SM r--t~tf~~(~T~o~p~s~oi~I)~~~~~~~~-=_~~~---------~~ (SP-SM) POORLY GRADED SAND with SILT, medium to coarse :,\li ,i 2.0 "1:.1 .. J . '1' .. .. SP- SM .. .j: L r ·1 i ... 1: '1/: ,: 17.0 grained, a trace of Gravel, brown, moist, medium dense. (Glacial Outwash) (SP) POORLY GRADED SAND with GRAVEL, medium to coarse grained, brown, moist, very dense to medium dense. (Glacial Outwash) 1988.9 :;:1 20 -: ---==--[>(I SS <0 ~ <0 ii2 ': f-0 (!) <Ii ..: SP ...J 3~ [XI ss 0 f-(/) f-Z (!i , ...J ...J W ~ n. f- i5~ Xl SS Fines = 7% ~ w z w (!) (Continued Next Page) n , J J .., Il. l'l -' ~ z UJ :::;: UJ -' 0-Il. ::> rJ) rJ) -' -' :c 0 UJ I-Z ;;: Il. m v N <D F= z ~ ~ z UJ :::;: UJ -' 0-Il. ::> rJ) rJ) -' -' :c 0 UJ I-Z ;;: 0-m v N <D Vi I-U UJ .., 0 oc 0- ~ 0 N 1 Vi I-U UJ .., 0 OC 0- U UJ Q, CLIENT NAI Black PROJECT NUMBER 16-249 W Q. I >-0:: I-W I-~ WlIl Q.¢:: TESTS w~ -1::2: 0 Q.::J ::2:z <l: en ~Xl SS ~[01 ss --1L Xl ss ~MSS -r.,1 '" N -' -' UJ ~ Il. l- I '" ~ UJ Z UJ IIIIUIIU I o,vlll'-' L..11~llleC:;llIl~ vVIII~C1lly 3012 North Sullivan Road, Suite C Spokane Valley, WA 99216 Telephone: 509-209-6262 tjUKINl'J NUMtst:K ts-1 PAGE 2 OF 2 Fax: 509-290-5734 () uj I(9 0 Q.O 0 ~-I ::J (9 SP ,50,5 PROJECT NAME Painted Hills Supplemental PROJECT LOCATION 4403 South Dishman-Mica Road MATERIAL DESCRIPTION (SP) POORLY GRADED SAND with GRAVEL, medium to coarse grained, brown, moist, very dense to medium dense . (Glacial Outwash) (continued) End of boring. Groundwater not encountered with 49' of hollow-stem auger in the ground. Groundwater not encountered immediately after withdrawal of the auger. Bore hole then abandoned. 1955.4 l'lL-________________________________________________________________________________________________ ~ 1111,"-,11\".1 I a .... lll .... L...11~1I1c:::c:::IIII~ VVllllJCUIY 3012 North Sullivan Road, Suite C Spokane Valley, WA 99216 Telephone: 509-209-6262 tjUKINu NUIVltj~K t:S.~ PAGE 1 OF 3 Fax: 509-290-5734 CLIENT NAI Black PROJECT NUMBER _1'-"6:....:-2"-'4=9 _____________ _ DATE STARTED ....;3"'-'1.:...:7-'..'1'-"6:.-__ _ COMPLETED ....;3"'-'..:..:18"'-'..:..:16=----__ _ DRILLING CONTRACTOR Johnson Exploration Drilling PROJECT NAME Painted Hills Supplemental PROJECT LOCATION 4403 South Dishman-Mica Road GROUND ELEVATION 2005.6 ft GROUND WATER LEVELS: HOLE SIZE ....;8::...!!..!in.",ch.!-"e""s ___ _ DRILLING METHOD -'HC!:o""II""ow!:....-"S'-"te""m"-!...:A""ug""e:.:..r _________ _ AT TIME OF DRILLING _-_--...!.N""o"-t ~en""c"'o!.!.nt""e'-'=re'""'d _______ _ LOGGED BY -'-P..!R-'.!.F _____ _ CHECKED BY -'-P--'TC.!.N'--__ _ :'f AT END OF DRILLING 71 .00 ft, Elev 1934.60 ft NOTES '5L AFTER DRILLING 73.50 ft, Elev 1932.10 ft w ...., Q.. P; I ~ffi --' I-~ W CO ~ [bE--':2 iii 0 Q..:::> ::;: :2z w « TESTS MATERIAL DESCRIPTION --' U) ~r_~O~---_+------r_----------r_~~~----~~~~~~~~~~----~----~~~~--~--~~----~ ~ L...!:'-(SM) SILTY SAND, fine to medium grained, with roots, dark ::l SM !!,H, brown, moist. I fil :,I(;,i 2.0 (Topsoil) ~ ~ ~~?rA ~~~~;d~~~~~n~~~~t~~~~t~:n~~'. medium to coarse ;:!j /. (Glacial Outwash) ~ ~1Xl SS 12-33 SC ~ ~ 1'-"_---}~(~'45~5)~ ~ 6.5 z w ::;: w --' 0.. 0.. ::> Ul Ul --' --' ~ r---1L Xl ss W I-Z ~ 0> ;:!j to iii ~ 24-20 (44) (3 ~ ~ Xl SS 24-29 ~ (53) o ~~~~~~~ "'I ~ W ~ 0.. U w Q" ~I ~1XI SS 25-28 ~ 1'--"--1----l-(5~3:L.1) I-o (!) ai S ~o ~1XI SS 10-18 (28) I-I'-"----}~~~ Ul I-Z (3 --' --' w ~ 0.. I- ~ c...l.L Xl SS 11-13 ~ 1'--"--I----l-C£!24:L.1 ) w z w GC SP Fines = 8% (GC) CLAYEY GRAVEL with SAND, fine to coarse grained, brown, moist, dense. (Glacial Outwash) (SP) POORLY GRADED SAND with GRAVEL, medium to coarse grained, a trace of Cobbles, brown, moist, very dense to medium dense. (Glacial Outwash) 1999.1 1993.6 (!)~--~----~----~----------~--~--~--------------------------------------------------------~ (Continued Next Page) n n r L. ~ (!) ...J ~ Z w :::;; W ...J 0.. 0.. => Cf) ~ ...J :;: o W I-Z ~ '" ;;; to i:: z ~ ~ z w :::;; W ...J "-"-=> Cf) ~ ...J :;: o W I-Z ~ '" ;;; to ~ W (3 0:: "-to ;; N ~ W (3 0:: 0.. U w !k .. to N .. .J b I -...J (!) '" :5 Cf) => o ~ I-Z (3 , ...J ...J W ~ "-I- I '" ~ w z w (!) I I CLIENT NAI Black PROJECT NUMBER 16-249 w a.. CJ)w I ~ffi f-~ 3:f-=> a.. <I:: w al OZ...J w~ ...J::2: ...J=>« Cl a..=> alO> ::2:z o~ « CJ) ~ fXl SS 28-37 (65) 40 ~ SS 50/5" 45 ~ SS 50/5" 50 IXI SS 50/5" ~ ~ IX] SS 8-17 (25) ~ Inland Pacific Engineering Company BORING NUMBER B·2 3012 North Sullivan Road, Suite C PAGE 2 OF 3 Spokane Valley, WA 99216 Telephone: 509-209-6262 Fax: 509-290-5734 PROJECT NAME Painted Hills SU!;1Qlemental PROJECT LOCATION 4403 South Dishman-Mica Road ~ en 0 IC) TESTS a.. 0 MATERIAL DESCRIPTION ~ ~...J => C) (SP) POORLY GRADED SAND with GRAVEL, medium to coarse grained, a trace of Cobbles, brown, moist, very dense to medium dense. (Glacial Outwash) (continued) SP (Continued Next Page) -I l J E CLIENT NAI Black ............................... -, ':;:''' ' .............. ~ _ ...... ',.... ..... ·'1 3012 North Sullivan Road, Suite C Spokane Valley, WA 99216 Telephone: 509-209-6262 Fax: 509-290-5734 CVI'.II'IU l'IUIVIDt:~ D-~ PAGE 3 OF 3 PROJECTNUMBER_1~6~-2~4~9 __________________________ _ PROJECT NAME Painted Hills Supplemental PROJECT LOCATION 4403 South Dishman-Mica Road I I-~ o..~ w~ Cl ii,;~M SS 21-11 v 1/\1 (32) ~ ~L-__ ~~~~ ;! Z w ~ w ~ Q. Q. :;J CI) CI) ~ ~ ~ 75 w ~ z ;;: Q. en <!j <D r:: z ~ ;! z w ~ w ~ Q. Q. :;J CI) CI) ~ ~ I o w ~ z ~ en 1li '" Cii ~ u w C3 Cl: Q. '" ;; ~I w ~ Q. U W Q. :::1 -'; '" ie ... b TESTS cr.i <.S o ~ SP 75.0 MATERIAL DESCRIPTION (SP) POORLY GRADED SAND with GRAVEL, medium to coarse grained, a trace of Cobbles, brown, moist, very dense to medium dense. .Y (Glacial Outwash) (continued) End of boring. Groundwater encountered at 71' with 75' of hollow-stem auger in the ground. Goundwater encountered at 73.5' 10 minutes later. Groundwater not encountered to cave-in depth of 15' immediately after withdrawal of the auger. Bore hole then abandoned. 1930.6 -.J C,!) J J IIi :5 CI) :;J o ~ ~ z (3 , ~ ~ w ~ Q. ~ :c III ~ w z w C,!)L-________________________________________________________________________________________________ ~ I I l J -1 -I J J _I ~ (!) ...J ~ W ::< w ...J Il. CLIENT NAI Black Inland Pacilic Engineering Company 3012 North Sullivan Road, Suite C Spokane Valley, WA 99216 Telephone: 509-209-6262 Fax: 509-290-5734 PROJECTNUMBER_1~6~-2~4=9 __________________________ _ DATE STARTED -'3"'-./1-'-'S"-/1'-"6'--____ _ COMPLETED ....;3=/..:..;19"'-./..:..;16=--____ _ DRILLING CONTRACTOR Johnson Exploration Drilling DRILLING METHOD ....,H...:.:o""I1""ow!.!.-'=S:..o.:te""m'-!...!..:A""ug,.,e"-r __________________ _ LOGGED BY ....,Pc...:R..!!F __________ _ CHECKED BY ....,P.....;TC!.N'--____ __ NOTES BORING NUMBER B·3 PROJECT NAME Painted Hills Supplemental PROJECT LOCATION 4403 South Dishman-Mica Road PAGE 1 OF 2 GROUND ELEVATION 2004.5 ft GROUND WATER LEVELS: HOLE SIZE -'S=--'i"-'nc=h=e::::.s ______ _ AT TIME OF DRILLING _-_--....:.N.,.,o::..t.o::enC!.:c""'o"'-unC!.:t""'erc:::e::::.d ______________ _ AT END OF DRILLING _---'.N-'-"o::..t .::<!enC!.::c"",o-,",unC!.::t.::<!erc:::e::::.d ______________ _ AFTER DRILLING -Not encountered MATERIAL DESCRIPTION ~~~+-----+-----------+---~~----~~~--~~ __ ~--------~--~-------------------------------4 (J) L.!." (ML) SANDY SILT, with roots, dark brown, moist. g ML ~·>1 1; (Topsoil) o :,\li .,\ 2.0 ~ ~ (GC) CLAYEY GRAVEL with SAND, fine to coarse grained, brown, ~ ~~ moist, dense. ~ (Glacial Outwash) to ~~X1 SS g ~ z w ::< w ...J Il. Il. :::> (J) ~ ...J ~ r--1Q.-[><1 ss W I-Z ~ '" ;;; ~ Cii o w 9 ~r--1L Xl ss (; N, (J) o w 8.0 ~ SC ~ ~12.0 GC ~ ~ (SC) CLAYEY SAND with GRAVEL, medium to coarse grained, brown, moist to wet, dense. (Glacial Outwash) (GC) SILTY CLAYEY GRAVEL with SAND, fine to coarse grained, brown, moist, medium dense. (Glacial Outwash) 2002.5 1996.5 1992.5 ~ 18.0 1986.5 Il. U W Il. ~'~X1 SS to <:'! ...J ...J W :s: Il. I- ~~X1 SS ~ w z U.J SP Fines = 6% (SP) POORLY GRADED SAND with GRAVEL, medium to coarse grained, a trace of Cobbles, brown, moist, very dense to medium dense. (Glacial Outwash) (!)L-__ ~ ____ L_ __________ L_~~~ ________________________________________________________________ ~ (Continued Next Page) _...I .J ..J ..., "-(!J ..J « f-z w ::E w ..J "-"-::::> en en ..J ..J :I: Cl W f-Z « "-'" .,. '" to F: z (5 ::; « f-z w ::E w ..J "-"-::::> en en ..J ..J :I: Cl W f-Z « "-'" .,. '" to CLIENT NAI Black PROJECT NUMBER 16-249 W 0... >-0:: I f-W f-~ WID 0...<1: TESTS W~ -'~ 0 o...=> ~z <t: en r--lL Xl ss --4!L W ss r-1L XI ss IIlIdilU r"dl;lIll; ~nglneenng vompany 3012 North Sullivan Road, Suite C Spokane Valley, WA 99216 Telephone: 509-209-6262 Fax: 509-290-5734 () en I(9 <.5 0...0 en r?-' ::i <9 tSUKINu NUMtsER B-3 PAGE 2 OF 2 PROJECT NAME Painted Hills Supplemental PROJECT LOCATION 4403 South Dishman-Mica Road MATERIAL DESCRIPTION (SP) POORLY GRADED SAND with GRAVEL, medium to coarse grained, a trace of Cobbles, brown, moist, very dense to medium dense . (Glacial Outwash) (continued) SP i3i~[XJss ~~ __ ~~ __ ~ __________ ~ __ ~~~5~O.~5 ____________________________________________________________ ~1~95~4~.O o 0:: "-to o "'I ~ w o 0:: "-U w Q, ::;' to '" f-Cl ~ m ~ en ::::> Cl f-en f-Z (5 , ..J ..J W ~ "-f- I m ::J Ci w z w End of boring. Groundwater not encountered with 49' of hollow-stem auger in the ground. Groundwater not encountered immediately after withdrawal of the auger. Bore hole then abandoned. (!JL-________________________________________________________________________________________________ -" I l •. .J c Inland Pacific Engineering Company Geotechnical Engineering and Consulting RELATIVE DENSITY OR CONSISTENCY VERSUS SPT N-VALVE COARSE-GRAINED SOILS FINE-GRAINED SOILS DENSITY N(BLOWSIFT) CONSISTENCY N(BLOWSIFT) Very Loose 0 -4 Very Soft 0-1 Loose 4 -10 Soft 2-3 Medium-Dense 11 -30 Rather Soft 4-5 Medium 6-8 Dense 31 -50 Rather Stiff 9 -12 Stiff l3 -16 Very Dense > 50 Very Stiff 17 -30 Hard > 30 USCS SOIL CLASSIFICATION MAJOR DIVISIONS GROUP DESCRIPTIONS Coarse-Gravel and Gravel GW Well Graded Gravel Grained Gravelly Soils (wilh Iiltlc or no fines) GP Poorly Graded Gravel Soils <50% coarse fraction Gravel GM Silty Gravel passes #4 sieve (with> 12% fines) GC Clayey Gravel <50% Sandy and Sand SW Well Graded Sand passes #200 Sandy Soils (wilh Iil1lc or nfl fines) SP Poorly Graded Sand sieve >50% coarse fraction Sand SM Silty Sand passes #4 sieve (with> 12% fines) SC Clayey Sand Fine-ML Silt Grained Silt and Clay CL Lean Clay Soils Liquid Limit < 50 OL Organic Silt and Clay (low plasticity) >50% MH Inorganic Silt passes #200 Salt and Clay CH Fat Clay sieve Liquid Limit > 50 OH Organic Clay and Silt (med to high plasticity) Highly Organic Soils PT Peat IMuck MODIFIERS MOISTURE CONTENT DESCRIPTION RANGE DESCRIPTION FIELD OBSERVATION Occasional <5% Dry Absence of moisture, dusty, dry to the touch Trace 5% -12% Moist Dry of optimum moisture content With >12% Wet Wet of optimum moisture content MAJOR DIVISIONS WITH GRAIN SIZE SIEVE SIZE 12" 3" 3/4" 4 10 40 200 GRAIN SIZE (INCHES) 12 3 0.75 0.19 0.079 0.0171 0.0029 Boulaers Cobbles Gravel Sand Silt and Clay Coarse I Fine Coarse IMediumlFine l I --' Inland Pacific Engineering Company GRAIN SIZE DISTRIBUTION 3012 North Sullivan Road, Suite C Spokane Valley, WA 99216 Telephone: 509-209-6262 Fax: 509-290-5734 CLIENT NAI Black PROJECT NAME Painted Hills SU(2(2lemental PROJECT NUMBER 16-249 PROJECT LOCATION 4403 South Dishman-Mica Road u.s. SIEVE OPENING IN INCHES I U.S. SIEVE NUMBERS I HYDROMETER 0.: (.!) ...J g W ::;: W ...J n. n. :::> en en ...J ...J :i: o w !Z ~ '" ~ <0 r:: z ~ w ::;: W ...J n. n. :::> en ~ ...J :i: o w ... z ~ '" ~ <0 ~ W a cr: n. <0 c; N ~ I-I ~ W ~ >-CD 0::: w z u:: I-z w () 0::: w Q.. I 6 4 3 100 I : 95 90 85 80 75 70 65 : 60 55 50 45 40 35 30 25 : 20 15 10 5 0 100 COBBLES I I W a cr: n. U w !b I BOREHOLE ::; :. B-1 .... o U") .. , b (.!) 5 en :::> o tii ... z (3 IZl B-2 • B-3 BOREHOLE • B-1 IZl B-2 '. W N B-3 iii z ~ (.!) OEPH 30.0 25.0 30.0 OEPH 30.0 25.0 -30.0 2 1.5 1 ~ 1/23/8 3 4 6 810 1416 20 30 40 50 60 100140200 II I ~ il I I I I I I \ 1\ 1\: 1.1 1\ :\ 1\: ~ \ : : \ i\ : \: \ \ ~\ : : \ \" 1\ : 1\ ~~\ : \ lU \\ : \ \\ \ \\ \ : \ \ ~ : : 1'\ ~t---: : i' ~ : [ .. ,,-:t:: t=I: 10 1 0.1 0.01 GRAIN SIZE IN MILLIMETERS GRAVEL I SAND SILT OR CLAY coarse I fine I coarse medium fine I Classification LL PL PI SP-SM Poorly Graded Sand with Silt SP-SM Poorly Graded Sand with Silt SP-SM Poorly Graded Sand with Silt 0100 060 030 010 %Gravel %Sand %Silt 19 2.679 1.065 0.31 21.9 71.2 19 1.992 0.977 0.228 13.9 77.9 -19 4.708 2.032 0.473 39.7 54.1 0.001 Cc Cu 1.37 8.65 2.10 8.72 1.85 9.95 %Clay 6.8 8.2 6.2 -, l l l J June 26,2017 Project No. 16-249D Mr. Bryan Walker NAIBlack 107 S Howard Suite 500 Spokane, WA 99201 EC Inland Pacific Engineering Company Geotechnical Engineering and Consulting Re: Geotechnical Evaluation Proposed Street Improvements 4403 South Dishman-Mica Road Spokane Valley, WA Dear Mr. Walker: As you authorized, we have completed a geotechnical evaluation for the proposed street improvements to the roadways adjacent to the above referenced site in Spokane Valley, Washington. The purpose of the evaluation is to provide earthwork recommendations and pavement design for the proposed improvements. This report summarizes the results of our site observations, engineering analyses and recommendations. PROJECT DESCRIPTION The project consists of street improvements to the roadways adjacent to the proposed Painted Hills residential development located at the above referenced address. The improvements consist of about 6,000 feet of roadway on South Dishman Mica Road, East Thorpe Road, and South Madison Road. P.O. Box 1566. Veradale, WA 99037 Phone 509-209-6262 l , J Geotechnical Evaluation Proposed Street Improvements Spokane Valley, WA Inland Pacific Engineering Company AVAILABLE INFORMATION Project No. 16-249D 4403 S Dishman-Mica Rd June 26, 2017 Page 2 We were provided a topographic survey for the project site by Whipple Consulting Engineers, Inc. (WCE). This topographic survey showed the existing roadways, existing structures, property lines, and existing ground surface elevation contours. This plan was prepared by WCE and was dated November 7,2013. The site was used as a golf course prior to our evaluation. The site is relatively level with some elevated golf greens and excavated areas for water hazards. The site is primarily grass-covered with scattered trees along the fairways and pine trees in the undeveloped area to the northwest. The clubhouse building is present at the southwest comer. We were also provided civil plans for the roadway improvements. The plans showed the layout and elevations of the proposed roadways and elevation contours. The plans were prepared by WeE and dated August 17,2016. In addition, we performed a preliminary geotechnical evaluation for the property in December 2013. The results of that evaluation, along with our opinions and recommendations, are summarized in our Preliminary Geotechnical Evaluation dated December 31, 2013. We also performed a geotechnical evaluation for certification of the existing levee along Chester Creek in April 2014. The results of that evaluation are summarized in our Geotechnical Evaluation report dated Februruy 12, 2015. Furthermore, we peliormed a supplemental geotechnical evaluation in July 2015 consisting often, 50-foot borings in the south half of the property. The results of that evaluation are summruized in our Geotechnical Evaluation Phase 2 report dated July 23,2015. We also performed a second supplemental geotechnical evaluation at the north end of the property to evaluate soil conditions at depth and to better defme the static groundwater elevation in this area. We then performed a full-scale drywell test on a drywell installed near Boring B-1 from our second supplemental geotechnical evaluation. The results of these evaluations are summarized in our Supplemental Geotechnical Evaluation dated April 19, 2016 and our Full-Scale Drywell Testing report dated June 28,2016. Lastly, we performed bore hole permeability testing at the north end of the property to evaluate infiltration rates at the depth of the drywell tested in our Full-Scale Drywell Testing report. We also tested infiltration rates at deeper depths. The results of that evaluation are summarized in our Bore Hole Permeability Testing report dated September 16, 2016. ., l J J Geotechnical Evaluation Proposed Street Improvements Spokane Valley, WA Inland Pacific Engineering Company Procedures FIELD EVALUATION Project No. 16-249D 4403 S Dishman-Mica Rd lune26,2017 Page 3 A geotechnical engineer from Inland Pacific Engineering Company (IPEC) observed the excavation of twelve test pits at the site. The test pits were excavated on February 23,2017 using a backhoe operated by an independent firm under subcontract to IPEC. A geotechnical engineer from IPEC observed the test pit excavations and logged the surface and subsurface conditions. After we logged each test pit, the test pit was immediately backfilled. The soils encountered in the test pits were visually and manually classified in the field by our field personnel in accordance with ASTM D 2488, "Description and Identification of Soils (Visual- Manual Procedures)". The samples were returned to our facility for review of the classification by a geotechnical engineer and potential laboratory testing. Soils Encountered Geologic maps indicate the soils in this area consist primarily of alluvial and/or glacially deposited silts, clays, sands, and gravels. According to the Soil Survey of Spokane County, the site soils are classified by the Natural Resource Conservation Service (NRCS) as Narcisse silt loam (1080), Endoaquolls and Fluvaquents (1200), Hardesty ashy silt loam (1040), Phoebe ashy sandy loam (3130), Bong ashy loam, moist (3022), and Urban land-Springdale, disturbed complex (7170). The native soils encountered in the teste pits were consistent with the NRCS data. At the surface, the test pits encountered topsoil ranging from about ~ to 2 feet. The topsoil consisted of clayey to silty sand, silty gravel, and lean clay. Below the topsoil, the test pits along Dishman-Mica and Thorpe Road generally encountered alluvial soils to their termination depths. The alluvial soils consisted oflean clay and clayey to silty sand. Below the topsoil, the test pits along Madison Road generally encountered glacial outwash or alluvial soils to their termination depths. The glacial outwash consisted of clayey and silty to poorly graded sand with silt and silty gravel. The alluvial soils consisted of lean clay and clayey sand. Groundwater was encountered in Test Pits TP-4 through TP-7 at depths ranging from 2 to 4 feet below existing grades at the time of our exploration. Seasonal and annual fluctuations of groundwater levels should be anticipated. Laboratory Testing We obtained samples of the sub grade soil from Test Pit TP-2, TP-4, and TP-7 during our site investigation. Grain size analyses and modified Proctor tests were perfOlmed by us on the samples obtained from TP-4 and TP-7 in accordance with ASTM D6913 and ASTM D1557, respectively. The results of the tests are attached. n n n J J Geotechnical Evaluation Proposed Street Improvements Spokane VaHey, WA Inland Pacific Engineering Company Project No. 16-249D 4403 S Dishman-Mica Rd June 26, 2017 Page 4 In addition, resilient modulus (Mr) tests were performed on the samples obtained from TP-4 and TP-7 in accordance with AASHTO T307. The Mr tests were performed by Braun Intertec in Bloomington, Minnesota. Attached are data sheets summarizing the tests performed. ANALYSIS AND RECOMMENDATIONS Subgrade Preparation After removing the asphalt from the existing roadways, we anticipate the sub grade will consist of existing roadway embankment fill. We have assumed that during the construction of the existing roadways, the fill was compacted in accordance with local jurisdiction standards. Where road widening is planned, we recommend removing any existing topsoil. We recommend that the upper 8 inches of the resulting sub grade be scarified, moistened or dried to within 3 percent of optimum moisture, and compacted to a minimum of 95 percent of the modified Proctor maximum dry density detennined in accordance with ASTM D 1557. Where fill is required, we recommend that it be similarly moisture conditioned and compacted. If there are areas that cannot be compacted, we recommend that the unstable soils be removed and replaced with soils similar to the surrounding sub grade soils. We recommend that the sub grade surface be shaped to provide for positive drainage to minimize the potential for water to pond in the sub grade. Because the site soils are low to highly frost- susceptible, it will be important to avoid creating "bathtubs" in the subgrade where water can pond and freeze, which could heave the pavement. If site grading and construction are anticipated during cold weather, recommend that good winter construction practices be observed. All snow and ice should be removed from excavated and fill areas prior to additional earthwork or construction. No fill or pavements should be placed on soil which have frozen or contain frozen material. Frozen soils should not be used as backfill or fill. Test Rolling Prior to placing the aggregate base, we recommend that all subgrade areas be proof-rolled with a loaded dump truck. This precautionary measure would assist in detecting any localized soft areas. Any soft areas discovered during the proof-rolling operation should be excavated and replaced with a suitable structural fill material. The structural fill should be similar to the existing subgrade soil type to provide a uniform sUbgrade. We recommend that the proof-rolling process be observed by an experienced geotechnical engineer to make the final evaluation of the subgrade. l _ ) 1 l --.J -.J , J I --.J Geotechnical Evaluation Proposed Street Improvements Spokane Valley, WA Inland Pacific Engineering Company Pavement Section Design Project No . 16-249D 4403 S Dishman-Mica Rd June 26, 2017 PageS We performed a pavement section analysis in accordance with the "AASHTO Guide for Design of Pavement Structures, 1993" by the American Association of State Highway and Transportation Officials (AASHTO). For our analysis, we were provided an Average Daily Traffic (ADT) value of 5,300 for Dishman-Mica Road, 1,400 for Thorpe Road, and 1,700 for Madison Road. We were also provided percent trucks values of 2 percent for Thorpe and Madison Road, and 5 percent for Dishman-Mica Road. We were provided a percent growth value of 1.1 percent. Based on these provided parameters, we calculated the following Equivalent Single Axle Loads (ESAL): • Dishman-Mica Road: • Thorpe Road: • Madison Road: 2,617,545 330,000 389,954 We used resilient modulus values from the laboratory test results of (Mr) of 5,821 pounds per square inch (psi) for Thorpe Road and an Mr of 11,985 psi for Dishman-Mica and Madison Road. We also used the following parameters in our analysis provided in Chapter 8 of the City of Spokane Valley Street Standards, dated December of2009: • Reliability: 90 percent • Standard Deviation: 0.45 • Initial Serviceability Index: 4.2 • Terminal Serviceability Index: 0 Dishman-Mica Road: 2.50 0 Thorpe Road: 2.25 0 Madison Road: 2.25 • Structural Layer Coefficients: • Asphalt: 0.42 • Aggregate Base: 0.l4 • Drainage Layer Coefficient: 0 Dishman-Mica Road: 1.05 0 Thorpe Road: 0.85 0 Madison Road: 0.95 Based on this data, we calculated the following design structural numbers: • Dishman-Mica Road: • Thorpe Road: • Madison Road: 3.4 3.1 2.5 l l Geotechnical Evaluation Proposed Street Improvements Spokane ValIey, WA Inland Pacific Engineering Company Based on our analysis, we recommend the following pavement sections: • Dishman-Mica Road: Project No . 16-249D 4403 S Dishman-Mica Rd June 26, 2017 Page 6 o 4 inches of asphalt overlying 12 inches of crushed aggregate base • Thorpe Road: o 4 inches of asphalt overlying 12 inches of crushed aggregate base • Madison Road: o 4 inches of asphalt overlying 6 inches of crushed aggregate base We recommend specifying crushed aggregate base meeting the requirements of the Washington Department of Transportation (WSDOT) Standard Specification 9-03.9(3) for crushed gravel surfacing (base course and/or top course). We recommend that the asphalt concrete pavement meet the requirements ofWSDOT Standard Specification for Class 'is inch HMA asphalt concrete pavements. We recommend that the crushed gravel surfacing be compacted to a minimum of 95 percent of the modified Proctor maximum dry density. We recommend that the asphaltic concrete surface be compacted to minimum of 92 percent of the Rice density. GENERAL RECOMMENDATIONS The analyses and recommendations submitted in this rep0l1 are based on the data obtained from the test pits excavated at the locations indicated on the Test Pit Location Map on Figure 3. It should be recognized that the explorations performed for this evaluation reveal subsurface conditions only at discreet locations across the project site and that actual conditions in other areas could vary. Furthelmore, the nature and extent of any such variations would not become evident until additional explorations are performed or until construction activities have begun. If significant variations are observed at that time, we may need to modify our conclusions and recommendations contained in this repo11 to reflect the actual site conditions. We made water level observations in the test pits at the times and conditions stated on the test pit logs. These data were interpreted in the text of this report. The period of observation was relatively short and fluctuation in the groundwater level may occur due to rainfall, flooding, irrigation, spring thaw and other seasonal and annual factors not evident at the time the observations were made. Design drawings and specifications and construction planning should recognize the possibility of fluctuations. I . J ......, I • J J Geotechnical Evaluation Proposed Street Improwmcnts Spokane Valley. WA Inland Pacilic Engineering Company ProjCCI No. 16-249D 4403 S Dishman-Mica Rd June 26.2017 Page 7 -------------- REMARKS This report is for the exclusive use of the addressee and the copied palties to use in design ofthe proposed project and to prepare construction documents. in the absence of our written approval. we make no representations and assume no responsibility to other palties regarding this repOlt. The data, analyses. and recommendations may not be appropriate for other structures or purposes. We recommend that palties contemplating other structures or purposes contact liS. Services performed by the geotechnical engineers for this project have been conducted in a manner consistent with that level of care ordinarily exercised by members of the prOfession currently practicing in this area under similar budget and time restraints. No warranty. expressed or implied, is intended or made . GENERAL REMARKS It has been a pleasure being of service to you for this project. If you have any questions or need additional information. please do not hesitate to call me at (509) 209-6262 at your convenience. Sincerely, Inland Pacific Engineering Company ~ Gregory J. Voigt, P.E. Project Engineer Attachments: Figure I, Site Location Map Figure 2, NRCS Map Figure 3, Test Pit Location Maps Logs of Test Pits Descriptive Terminology Laboratory Test Results Paul T. Nelson, P.E . Principal Engineer .., I ., . , :l I j . J l -, .J IP EC Inland Pacific Engineering CC'mpan:. Geotechnical Engin~eliJ1g and C omulling FIGURE 1 Site Location M~ Project No. 16-249D Proposed Street Improvements June 26, 2017 4403 S Dislunan-Mica Rd Spokane Valley, W A FIGURE 2 ..., I ..., I _ J n _J NRCSMap 1 J IPEC Project No. 16-249D Proposed Street Improvements June 26, 2017 Inland Pacific Engineering Company 4403 S Dislunan-Mica Rd GeoteclmicaI Engimering md Consulting Spokane Valley, W A J FIGURE 3 l l 1 -' Test Pit Location Map 1 IPEC Project No. 16-249D Proposed Street Improvements June 26, 2017 Inland Pacific Engineering Company 4403 S Dishman-Mica Rd Geoteclmical Engineering and Consulting Spokane Valley, W A J -(/) >-() ~ o 0:: [l. () w !h en " N b (!) ai S (/) ::::> o >-(/) >-z C3 [l. >- I ID ~ W Z W EC CLIENT NAI Black Inland Pacific Engineering Company 3012 North Sullivan Road, Suite C Spokane Valley, WA 99216 Telephone: 509-209-6262 Fax: 509-290-5734 PROJECTNUMBER_1~6~-2~4=9D=-______________________ __ LOGGED BY GV NOTES UJ Q.. >-0:: oj J: I-UJ I-~ UJal c..:i 0...<1=' ...J~ oj UJ~ 0 Q..::J =i ~z « U) 0.0 <.) I(9 Q..a ~...J (9 CHECKED BY PTN MATERIAL DESCRIPTION (SC) CLAYEY SAND, fine-grained, brown, moist. (Alluvium) End of test pit. Groundwater not encountered. Test pit immediately backfilled. TEST PIT NUMBER TP-1 PAGE 1 OF 1 f (!)~ ____________________________________________________________________________________________ -J n I c J J CLIENT NAI Black Inland Pacific Engineering Company 3012 North Sullivan Road, Suite C Spokane Valley, WA 99216 Telephone: 509-209-6262 Fax: 509-290-5734 PROJECTNUMBER_1~6~-2~4=9~D ________________________ _ ~ DATE STARTED ~2~/2",,3,,-,/1,-,-7 ______ _ COMPLETED ~2~/2",,3,,-,/1,-,-7 ____ __ (!) ::; a. f- :c aJ ..J ~ W Z w LOGGED BY NOTES w 0.. I ~ffi I-~ WCD 0..<1= --l~ w~ 0 0..::> ~z <t: U) 0.0 GV () cr.> cj :1:<.9 cr.> 0..0 ~--l ::i <.9 CHECKED BY PTN MATERIAL DESCRIPTION (SC) CLAYEY SAND, fine-grained, brown, moist. (Alluvium) End of test pit. Groundwater not encountered. Test pit immediately backfilled. TEST PIT NUMBER TP-2 PAGE 1 OF 1 f (!)L-____________________________________________________________________________________________ ~ , ) l _ J l . 1 . I I --' J .J E CLIENT NAI Black Inland Pacific Engineering Company 3012 North Sullivan Road, Suite C Spokane Valley, WA 99216 Telephone: 509-209-6262 Fax: 509-290-5734 PROJECTNUMBER_1~6~-2~4~9~D ________________________ _ ~ DATE STARTED ....!2:!;/2:!31.!../1!..!.7 ______ _ COMPLETED --.'-2""/2""3"-/1!...!.7 ____ _ (!) z (!) ~ o iii I-0 W (3 '" D-o W ~ ~ en '" N r-- £:! ~ I-0 (!) ai :5 II) ::::J 0 l-II) I-Z (3 ..J ..J ~ D-~ I '" ..J ~ w Z w (!) EXCAVATION CONTRACTOR ..!.A-"I.t:.pi"-,n-"-e-=E~x""ca"-,v",,a""'tin,,,,gL-______ _ SM - •. ·1· 1. : I:· .: 5.0 End of test pit. Groundwater not encountered. Test pit immediately backfilled. TEST PIT NUMBER TP-3 PAGE 1 OF 1 MATERIAL DESCRIPTION f ·1 J CLIENT NAI Black Inland Pacific Engineering Company 3012 North Sullivan Road, Suite C Spokane Valley, WA 99216 Telephone: 509-209-6262 Fax: 509-290-5734 PROJECT NUMBER _1'-"6C-"-2:...!4-"C9D"'--___________ _ ~ DATE STARTED 2/23/17 COMPLETED -=2=:..:12:.:3;:...;/1:..:..7 __ _ C) 13 EXCAVATION CONTRACTOR ...!.A...!!I"'piC!.!ne><...!:E"'xc""a"'va,.,t!'-'in"'-9 ______ _ ~ EXCAVATION METHOD -=B::..:a'-"c"-"khc.:.:0:..:::e'--__________ _ TEST PIT NUMBER TP-4 PAGE 1 OF 1 PROJECT NAME Proposed Street Improvements PROJECT LOCATION -'S"'p""o"-'-ka"-!n.!.>e:....cV'-"a"'II"'-eyu.,-'-W!.!.A-'--________ _ GROUND ELEVATION TEST PIT SIZE 30 inches GROUND WATER LEVELS: '5l-AT TIME OF EXCAVATION 2.00 ft ~~~------------~ LOGGED BY -'G"'-V"--_____ CHECKED BY ...!P--'TC!.N"--___ Y. AT END OF EXCAVATION ...!.2:,..0,,-,0,,-,ft~ _________ _ ~ NOTES _____________________ .sr AFTER EXCAVATION 2.00 ft ~~~~====~==========~==~~================~~~~~~~~~~~~~======================~ en ::l UJ I a.. rIl I ~ffi .... I-~ UJ!D z B:i~ ~~ ~ 0 a..::J o ~z TESTS MATERIAL DESCRIPTION ~ C7j ~~o~.o~--_r-----_r-_r.~~--~~~~~~~~~~~~~~----~----------~ ~ L..!" (CL) LEAN CLAY with SAND, dark brown, moist. E'i '>i'; (Topsoil) w .... In :) 0 z « .~ "t .... z 9 z r--1d-C) Ui w 0 .... z w ::E w ~ Fines = 38% .' 2.0 • SM <I· (SM) SILTY SAND, fine-grained, with seams of Silt, brown, water-bearing. I (Alluvium) :··1:: " .... 0.. en -' -' I 0 w .... 5.0 z .: 5.0 ~ 0 Ol ..,. N to End of test pit. iii .... u w Groundwater encountered at 2 feet. (3 '" 0.. ~ Test pit immediately backfilled. 0 N -(/) .... u !!l 0 '" 0.. U w fh ~ Ol ..,. N ~ ~ to ..: 0 C) ai :) en :J 0 .... (/) .... z (3 -' -' ~ 0.. ~ I In -' ~ w z w C) l .' PE CLIENT NAI Black Inland Pacific Engineering Company 3012 North Sullivan Road, Suite C Spokane Valley, WA 99216 Telephone: 509-209-6262 Fax: 509-290-5734 PROJECT NUMBER _1""6'-"-2'-'4=90=--___________ _ ~ DATE STARTED -'2:'-'/2""'3"-/1'-'.7 ___ _ COMPLETED -,2:,-,/2",,3"-,/1,,-7 __ _ (!) 15 EXCAVATION CONTRACTOR ...:.A-"I"'pi"-'ne"-'=E~xc""a'_"va=.!t"_'in"'_g ______ _ ~ EXCAVATION METHOD -'B""a"-'c"'k!-"ho"-'e'--__________ _ ,,' I; ,I :~·.;·.2.0 ". MATERIAL DESCRIPTION ~ (CL) LEAN CLAY with SAND, brown, wet. ~ (Alluvium) ~ o Ol ~ ~ iii o LU (3 a: a. <0 ;; '" iii o LU (3 a: a. ~ CL 0;;i ~ .~ %% ~~5.0 End of test pit. Groundwater encountered at 2 feet. Test pit immediately backfilled. ~ U LU g, do ... N " !::! "? b ~ m S Ul ::l 0 I-Ul I-Z C3 ...:, ...J ~ a. !::: I m ...J ~ - -- LU Z LU (!) TEST PIT NUMBER TP-5 PAGE 1 OF 1 l l J J J If. o 0> '" :b ~ f-&l o '" a. <D ;; N iii o w o '" a. U w ~ '-; 0> '" Co; S £:! ": f-0 (!) <Ii ::i (/J :::J 0 f-(/J f-Z (3 ...J ...J ~ a. ~ I m ...J ~ w z w (!) E - Inland Pacific Engineering Company 3012 North Sullivan Road, Suite C Spokane Valley, WA 99216 Telephone: 509-209-6262 Fax: 509-290-5734 MATERIAL DESCRIPTION TEST PIT NUMBER TP-6 PAGE 1 OF 1 (SP-SM) POORLY GRADED SAND with SILT, fine to coarse-grained, brown, moist to water-bearing. (Glacial Outwash) .. : 5.0 End of test pit. Groundwater encountered at 3 1/2 feet. Test pit immediately backfilled. ! I' '.J -, .1 "'1 _.J .J Inland Pacific Engineering Company 3012 North Sullivan Road, Suite C Spokane Valley, WA 99216 Telephone: 509-209-6262 TEST PIT NUMBER TP-7 PAGE 1 OF 1 Fax: 509-290-5734 CLIENT NAI Black PROJECT NAME Proposed Street Improvements PROJECTNUMBER_1~6~-2~4~9~D ________________________ _ PROJECTLOCATION~S~p""o::..:.k~an~e~V~a~lI~ey~,~W~A~ ________ __ ~ DATE STARTED 2/23/17 COMPLETED .....:2:::.;12:;3""/1-'.:7'--____ _ GROUND ELEVATION TEST PIT SIZE 30 inches C> 6 EXCAVATION CONTRACTOR ...!.A.!!.lp"-'i!.!:ne~Ex"'c""ac!.!va"_'t!!.!in,..g ________ __ GROUND WATER LEVELS: iii ~ EXCAVATION METHOD .....:B""a""c::..:,kh""o""e'--__________ _ .sz. AT TIME OF EXCAVATION 4.00 ft ~~~----------------~ LOGGED BY ....;G:o-V-'-________ CHECKED BY -'P..."T""N'--_____ .Y AT END OF EXCAVATION _4.:..:,.=.;00=-ft=-=--_________ _ W NOTES "L AFTER EXCAVATION 4.00 ft ~~~~====;===========;===;=~================~~~~~~~~~~====~======================~ ~ -' I o W >-Z ~ o en ~ I f-~ Cl..<1= W~ o W Cl.. >-0:: f-W WIIl ...J~ Cl..:J ~z (f) TESTS MATERIAL DESCRIPTION w~O::..:..O~--_+----------_+--_r~~----~~~~~~~~~~~~--------~~~------~--------------~ ~:"'~ (CL) LEAN CLAY with SAND, trace roots, dark brown, moist. t;i '/.;", (Topsoil) W :;; CL :". I;: .~ ~ ~~~ z « ~ ~ ~-2L W o >-z W ::;; W ~ II) -' -' I o W ~ 5.0 ~ o en ~ II) t; W o 0:: a-w (; N Ui >-U W o 0:: a- U W e, b C> <ri :3 II) ::> o >-II) >-z (5 a->- :r: m -' ~ W Z W ;:" .. ,'. 2.0 Fines = 50% (CL) SANDY LEAN CLAY, brown, moist to wet. (Alluvium) End of test pit. Groundwater encountered at 4 feet. Test pit immediately backfilled. C>~ ____________________________________________________________________________________________ _J n J :; b ~ --.J m J 1 _ :5 rn ::> o >-rn >-z (!j 0.. >- r m ~ w z w Inland Pacific Engineering Company 3012 North Sullivan Road, Suite C Spokane Valley, WA 99216 Telephone: 509-209-6262 Fax: 509-290-5734 TEST PIT NUMBER TP-8 PAGE 1 OF 1 PROJECT NAME Proposed Street Improvements PROJECT LOCATION -'S"'p""o"'k!O!an-"'e:....V!..!a""".::.eyu,-'-W.:..:A-'--__________ _ GROUND ELEVATION ____ _ TEST PIT SIZE 30 inches GROUND WATER LEVELS: AT TIME OF EXCAVATION --=-=...!.N!.!:o~t ~en~c~o~un~t~er~ed~ _____ _ MATERIAL DESCRIPTION (SC) CLAYEY SAND with GRAVEL, fine to medium-grained, brown , moist. (Glacial Outwash) End of test pit. Groundwater not encountered. Test pit immediately backfilled. J ~~--------------------------------------------------------------------------------------------~ I _., ..., ., 1 J .J Cf. o m '" :b iii ti w (3 0:: Il. <D ;; '" iii l-t) W (3 0:: Il. t) W g, m '" N I Il. -' l- I <ll ..J ~ W Z w EC LOGGED BY GV NOTES w CL t) J: >-0:: oj ~w I(9 ~~ WCO 0 CL<l= ....J::2: oj CLa w~ ~....J 0 CL~ ::i ::2:z (9 ~ en 0.0 ~:.' SC II .~H;· :,\ (i. ,\ SM Inland Pacific Engineering Company 3012 North Sullivan Road, Suite C Spokane Valley, WA 99216 Telephone: 509-209-6262 TEST PIT NUMBER TP-9 Fax: 509-290-5734 1.0 CHECKED BY PTN MATERIAL DESCRIPTION (SM) SILTY SAND with GRAVEL, fine to medium-grained, brown, moist. (Glacial Outwash) PAGE 1 OF 1 ··2.0 P 0 0 pc , )< p :-o 0 GM ). ) < o ~I;- ). < P ~·~I;-5.0 (GM) SILTY GRAVEL, fine to coarse-grained, brown, moist. (Glacial Outwash) End of test pit. Groundwater not encountered. Test pit immediately backfilled. ~~--------------------------------------------------------------------------------------------~ ~, •• J J l I ~ I -' E·C Inland Pacific Engineering Company Geotechnical Engineering and Comulting RELATIVE DENSITY OR CONSISTENCY VERSUS SPT N-V AL VE COARSE-GRAINED SOILS FINE-GRAINED SOILS DENSITY N(BLOWSIFT) CONSISTENCY N(BLOWSIFT) Very Loose 0-4 Very Soft 0-1 Loose 5 -10 Soft 2-3 Medium-Dense 11 -30 Rather Soft 4-5 Medium 6-8 Dense 31 -50 Rather Stiff 9 -12 Stiff 13 -16 Very Dense > 50 Very Stiff 17 -30 Hard >30 USCS SOIL CLASSIFICATION MAJOR DIVISIONS GROUP DESCRIPTIONS Coarse-Gravel and Gravel GW Well Graded Gravel Grained Gravelly Soils (\\ilh linle (I'" 00 rUII::5) GP Poorly Graded Gravel Soils <50% coarse fraction Gravel GM Silty Gravel passes #4 sieve (with> 12% fines) GC Clayey Gravel <50% Sandy and Sand SW Well Graded Sand passes #200 Sandy Soils (\\;lhlinlc A"wrUlcs) SP Poorly Graded Sand sieve >50% coarse fraction Sand SM Silty Sand passes #4 sieve (with >12% fines) SC Clayey Sand Fine-ML Silt Grained Silt and Clay CL Lean Clay Soils Liquid Limit < 50 OL Organic Silt and Clay (low plasticity) >50% MH Inorganic Silt passes #200 Salt and Clay CH Fat Clay sieve Liquid Limit> 50 OH Organic Clay and Silt (med to high plasticity) Highly Organic Soils PT Peat IMuck MODIFIERS MOISTURE CONTENT DESCRIPTION RANGE DESCRIPTION FIELD OBSERVATION Occasional <5% Dry Absence of moisture, dusty, dry to the touch Trace 5% -12% Moist Dry of optimum moisture content With >12% Wet Wet of optimum moisture content MAJOR DIVISIONS WITH GRAIN SIZE SIEVE SIZE 12" 3" 3/4" 4 10 40 200 GRAIN SIZE (INCHES) 12 3 0.75 0.19 0.079 0.0171 0.0029 Boulders I Cobbles Gravel Sand Silt and Clay -Coarse I Fine Coarse I Medium I Fine n II l L Inland Pacific Engineering Company GRAIN SIZE DISTRIBUTION IPE 3012 North Sullivan Road, Suite C Spokane Valley, WA 99216 Telephone: 509-209-6262 Fax: 509-290-5734 CLIENT NAI Black PROJECT NAME ProQosed Street ImQrovements PROJECT NUMBER 16-2490 PROJECT LOCATION SQokane Valley, WA U.S. SIEVE OPENING IN INCHES I U.S. SIEVE NUMBERS I HYDROMETER ..., Il. <!l z <!l u; w o ... z w ::;; w ~ ~ ..J I o w ... z ~ o ~ N <0 ~ Z § z <!l in w o ... z w ::;; w ~ en ..J ..J I o w ... Z ~ o 0> .,. N <0 ::: en ... () w ..., 0 oc Il. <0 0 N en ... () I-J: c.9 iIi $ >-III ~ w z u:: I-z w u ~ w a.. 6 4 3 100 I 95 90 85 80 75 70 65 60 55 50 45 40 35 30 25 20 15 10 5 0 100 I w COBBLES ..., I 0 oc Il. () w BOREHOLE OEPTI-!h ~. TP-4 3.0 ;;; ~= TP-7 3.0 g ~ .., ... 0 <!l ai :3 BOREHOLE OEPTI-en :J ~. TP-4 3.0 en !z= TP-7 3.0 (3 w N u; Z ;;: oc <!l 2 1.5 1314 W: 3 :1-6 810 1416 20 30 40 5060 100140200 I 1"-r: T ~ ~I I I ~ -.... ) ~\ \ 1\\ I~ I~~ :I\" :\ ~. t1\ I\~ , \ : 10 1 0.1 0.01 GRAIN SIZE IN MILLIMETERS GRAVEL I SAND SILT OR CLAY I I coarse coarse fine medium fine C lassificatio n LL PL PI SILTY SAND(SM) SANDY LEAN CLAY(CL) 0100 060 030 010 %Gravel %Sand %Silt 12.7 0.245 3.4 58.8 9.5 0.268 0.2 49.7 0.001 Cc Cu %Clay 37.8 50.1 L L L _ L ---1 L Re~i1ient Modulus Testing -AASHTO T307 US Customary Units Date: April 10,2017 Client: Inland Pacific Engineering Company Paul Nelson P.O. Box 1566 Veradale, WA 99037 Sample Information Braun Sample 10.1 File Name: Sample Type: Test Date: Comments' COLUMN # I Chamber Confining PARAMETER Pressure DESIGNATION S3 UNIT psi PRECISION SEQUENCE I 6.0 Type 2 06-Apr-20 17 Spokane Valley. WA 2 3 Nominal Cycle Maximum No. Axial Stress Scyclic cl psi --- - I 2 2.1 3 4 5 COLUMN AVERAGE STANDARD DEV. Sample Diameter, in.: Sample Height. in.: Desired M.C., %: Desired Dry Density., pcf: 4 5 6 7 Actual Actual Actual Actual Applied Applied Applied Applied Maximum Cyclic Contact Maximum Axial Load Load Axial Load Stress Pm ax Pcyclic Pcontact Smax Ibs. Ibs. Ibs. psi 13.4 11.0 2.4 2.2 13.4 11.0 2.4 2.1 13.2 10.7 2.5 2.1 13.3 10.9 2.4 2.1 13.5 11.1 2.5 2.2 13.4 10.9 2.4 2.1 0.12 0.12 0.03 0.02 J 2.82 5.58 13.5 98.8 8 Actual Applied Cyclic Stress Scyclic psi 1.8 1.8 1.7 1.8 1.8 1.8 0.02 9 10 Actual Recov Def. Applied LVDTI Contact Reading Stress Scontact HI psi inches 0.4 0.00074 0.4 0.00071 0.4 0.00078 0.4 0.00085 0.4 0.00082 0.4 0.00078 0.00 0.00006 L --.l Project: BI702069 Project Description: Resilient Modulus Test AASHTOT307 Client 10: Station: Proposed Street Improvements TP-4 Sample M.e., % before, after: Sample Dry Den., pcf: Failed in Shear?: Triaxial Shear Strength, psi' II 12 Recov Def. Average LVDT2 Recov Def. Reading LVDT I and LVDT2 H2 H average inches inches 0.00063 0.00069 0.00060 0.00066 0.00067 0.00072 0.00074 0.00079 0.00071 0.00077 0.00067 0.00073 0.00005 0.00006 13.9,13.6 97.8 YES 44.2 13 Resilient Strain in/in 0.00012 0.00012 0.00013 0.00014 0.00014 0.00013 0.00001 J 14 Resilient Modulus Mr psi --- 14,342 15,062 13,377 12,325 12,968 13,615 1,091 L _. L _ ~ l~ L I COLUMN # II I I 2 I 3 I 4 I 5 I 6 I 7 I 25.2 21.3 3.9 4.1 2 25.2 21.3 3.9 4.0 SEQUENCE 2 6.0 4.0 3 25.2 21.4 3.8 4.0 4 25.2 21.6 3.6 4.1 5 25.1 21.2 3.8 4.0 I I COLUMN AVERAGE 25.2 21.4 3.8 4.0 0.07 0.14 0.12 0.01 STANDARD DEV. I COLUMN # II I I 2 I 3 I 4 I 5 I 6 I 7 I 35.7 31.0 4.7 5.7 2 35.4 30.4 5.1 5.7 SEQUENCE 3 6.0 5.7 3 35.7 31.0 4.8 5.7 4 35.6 30.7 4.9 5.7 5 35.5 30.7 4.8 5.7 COLUMN AVERAGE 35.6 30.8 4.8 5.7 STANDARD DEV. 0.12 0.25 0.14 0.02 I COLUMN # II I I 2 I 3 I 4 I 5 I 6 I 7 I 50.7 44.2 6.5 8.1 2 50.6 43.8 6.8 8.1 SEQUENCE 4 6.0 8.1 3 50.6 43.9 6.7 8.1 4 50.5 43.8 6.7 8.1 5 50.6 44.9 5.8 8.1 COLUMN AVERAGE 50.6 44.1 6.5 8.1 STANDARD DEV. 0.07 0.44 0.41 0.01 J I 8 I 3.4 3.4 3.4 3.5 3.4 3.4 0.02 I 8 I 5.0 4.9 5.0 4.9 4.9 4.9 0.04 I 8 I 7.1 7.0 7.1 7.0 7.2 7.1 0.07 Sample ID: I Project: B 1702069 Sheet No.2 of 7 9 0.6 0.6 0.6 0.6 0.6 0.6 0.02 9 0.8 0.8 0.8 0.8 0.8 0.8 0.02 9 1.0 1.1 1.1 1.1 0.9 1.0 0.07 ~ J L~ ~..--J I 10 I II I 0.00168 0.00149 0.00175 0.00156 0.00154 0.00136 0.00168 0.00149 0.00168 0.00149 0.00167 0.00148 0.00008 0.00007 I 10 I II I 0.00257 0.00230 0.00267 0.00239 0.00257 0.00230 0.00267 0.00239 0.00278 0.00249 0.00260 0.00233 0.00006 0.00005 I 10 I II I 0.00385 0.00414 0.00383 0.00412 0.00384 0.00413 0.00365 0.00393 0.00384 0.00414 0.00380 0.00409 0.00008 0.00009 ~ J J J 12 I 13 I 14 I 0.00159 0.00028 12,106 0.00165 0.00030 11,586 0.00145 0.00026 13,326 0.00158 0.00028 12,307 0.00159 0.00028 12,060 0.00157 0.00028 12,277 0.00008 0.00001 643 12 I 13 I 14 I 0.00244 0.00044 11,443 0.00253 0.00045 10,797 0.00243 0.00043 11,461 0.00253 0.00045 10,906 0.00264 0.00047 10,474 0.00246 0.00044 11,016 0.00006 0.00001 429 12 I 13 I 14 I 0.00400 0.00071 9,961 0.00397 0.00071 9,914 0.00398 0.00071 9,925 0.00379 0.00068 10,400 0.00399 0.00071 10,110 0.00395 0.00070 10,062 I 0.00009 0.00002 204 L_ L_ , I L- I I COLUMN # SEQUENCE 5 I I COLUMN # SEQUENCE 6 I COLUMN # SEQUENCE 7 L_ L-...; II 1 I 2 6.0 10.1 I COLUMN AVERAGE STANDARD DEV. II 1 I 2 4.0 2.1 II COLUMN AVERAGE II STANDARD DEV. II 1 I 2 4.0 4.0 COLUMN AVERAGE STANDARD DEV. L- I 3 I 1 2 3 4 5 I 3 I 1 2 3 4 5 I 3 I 1 2 3 4 5 L- 4 I 5 I 6 I 7 62.9 56.3 6.6 10.1 62.8 56.0 6.8 10.1 62.9 54.9 8.0 10.1 62 .9 55.0 7.9 10.1 63.0 54.9 8.1 10.1 62.9 55.4 7.5 10.1 0.05 0.68 0.71 0.01 4 I 5 I 6 I 7 13.0 11.0 2.0 2.1 13.0 11.0 2.0 2.1 13.0 10.9 2.1 2.1 13.0 11.0 2.0 2.1 13.0 11.0 2.0 2.1 13.0 11.0 2.0 2.1 0.04 0.05 0.04 0.01 4 I 5 I 6 I 7 24.8 21J 3.5 4.0 24.8 21.7 3.1 4.0 24.7 21.4 3.3 4.0 25 .0 21.7 3.3 4.0 24.8 21.4 3.4 4.0 24.8 21.5 3.3 4.0 0.09 0.18 0.14 0.02 L J I 8 I 9.0 9.0 8.8 8.8 8.8 8.9 0.11 I 8 I 1.8 1.8 1.8 1.8 1.8 1.8 0.01 I 8 I 3.4 3.5 3.4 3.5 3.4 3.5 0.03 Sample ID: 1 Project: B 1702069 Sheet NO.3 of 7 ~ 9 1.1 1.1 1J 1J 1J 1.2 0.11 9 0.3 0.3 0.3 0.3 0.3 0.3 0.01 9 0.6 0.5 0.5 0.5 0.6 0.5 0.02 -.J ~ ~ I 10 I 11 r-- 0.00483 0.00524 0.00481 0.00521 0.00482 0.00523 0.00462 0.00500 0.00481 0.00521 0.00478 0.00518 0.00009 0.00010 I 10 I 11 I 0.00057 0.00085 0.00059 0.00088 0.00062 0.00092 0.00063 0.00093 0.00058 0.00087 0.00060 0.00089 0.00003 0.00004 I 10 I 11 I 0.00194 0.00206 0.00203 0.00215 0.00193 0.00205 0.00208 0.00220 0.00195 0.00207 0.00199 0.00211 0.00006 0.00007 ~J '-J -~ _ J 12 I 13 I 14 0.00503 0.00090 10,059 0.00501 0.00089 10,073 0.00502 0.00090 9,840 0.00481 0.00086 10,292 0.00501 0.00090 9,855 0.00498 0.00089 10,024 I 0.00010 0.00002 186 12 I 13 I 14 I 0.00071 0.00013 13,985 0.00073 0.00013 13,512 0.00077 0.00014 12,725 0.00078 0.00014 12,771 0.00073 0.00013 13,602 0.00074 0.00013 13,319 0.00003 0.00001 551 12 I 13 I 14 I 0.00200 0.00036 9,597 0.00209 0.00037 9,312 0.00199 0.00036 9,649 0.00214 0.00038 9,128 0.00201 0.00036 9,541 0.00205 0.00037 9,445 0.00007 0.00001 219 L ~ " L L-L-~ L I COLUMN II II 1 I 2 I 3 I 4 I 5 I 6 I 7 1 36.6 32.1 4.5 5.9 2 36.6 32.2 4.4 5.9 SEQUENCE 8 4.0 5.9 3 36.6 32.0 4.6 5.9 4 36.7 32.1 4.6 5.9 5 36.6 32.0 4.6 5.9 I I COLUMN AVERAGE 36.6 32.1 4.5 5.9 0.03 0.08 0.09 0.00 STANDARD DEV. I COLUMN Ii II 1 I 2 I 3 I 4 I 5 I 6 I 7 1 48.8 43.2 5.5 7.8 2 48.6 42.9 5.7 7.8 SEQUENCE 9 4.0 7.8 3 48.6 42.1 6.5 7.8 4 48.7 43.8 4.9 7.8 5 48.8 42.8 5.9 7.8 II COLUMN AVERAGE 48.7 43.0 5.7 7.8 II STANDARD DEV. 0.09 0.63 0.59 0.01 I COLUMN II II 1 I 2 I 3 I 4 I 5 I 6 I 7 1 61.2 54.6 6.6 9.8 2 61.3 54.0 7.2 9.8 SEQUENCE 10 4.0 9.8 3 61.2 53.2 8.0 9.8 4 61.2 54.4 6.8 9.8 5 61.2 53.8 7.4 9.8 COLUMN AVERAGE 61.2 54.0 7.2 9.8 STANDARD DEV. 0.04 0.53 0.53 0.01 J I 8 I 5.2 5.2 5.1 5.2 5.1 5.2 0.01 I 8 I 6.9 6.9 6.8 7.0 6.9 6.9 0.10 I 8 I 8.8 8.7 8.6 8.7 8.6 8.7 0.09 Sample 10: 1 Project: B 1702069 Sheet No.4 of7 J J 9 I 10 0.7 0.00319 0.7 0.00333 0.7 0.003 18 0.7 0.003 17 0.7 0.00346 0.7 0.00327 0.01 0.00012 9 I 10 0.9 0.00444 0.9 0.00462 1.1 0.00463 0.8 0.00462 1.0 0.00463 0.9 0.00459 0.10 0.00008 9 I 10 1.1 0.00562 1.2 0.00566 1.3 0.00565 1.1 0.00561 1.2 0.00539 1.2 0.00558 0.09 0.00011 l --.J L -.J J -' ~ -~ I 11 I 12 I 13 I 14 I 0.00338 0.00328 0.00059 8,804 0.00353 0.00343 0.00061 8,450 0.00337 0.00328 0.00059 8,788 0.00336 0.00327 0.00058 8,845 0.00367 0.00356 0.00064 8,085 0.00346 0.00336 0.00060 8,595 0.00013 0.00013 0.00002 326 I 11 I 12 I 13 I 14 I 0.00469 0.00457 0.00082 8,523 0.00488 0.00475 0.00085 8,120 0.00489 0.00476 0.00085 7,969 0.00489 0.00475 0.00085 8,295 0.00489 0.00476 0.00085 8,095 0.00485 0.00472 0.00084 8,200 0.00009 0.00008 0.00002 214 I 11 I 12 I 13 I 14 I 0.00594 0.00578 0.00103 8,496 0.00598 0.00582 0.00104 8,358 0.00596 0.00580 0.00104 8,256 0.00591 0.00576 0.00103 8,497 0.00568 0.00554 0.00099 8,735 0.00589 0.00574 0.00103 8,468 0.00012 0.00012 0.00002 180 1-L L L-l L L L L I COLUMN # II I I 2 I 3 I 4 I 5 I 6 I 7 I I 11.1 9.5 1.6 1.8 2 11.1 9.5 1.6 1.8 SEQUENCE II 2.0 1.8 3 11.1 9.4 1.7 1.8 4 11.1 9.5 1.6 1.8 5 11.0 9.4 1.7 1.8 I I COLUMN AVERAGE 11.1 9.5 1.6 1.8 0.03 0.08 0.05 0.01 STANDARD DEV. I COLUMN # II I I 2 I 3 I 4 I 5 I 6 I 7 I 23.1 20.2 2.9 3.7 2 23.0 20.2 2.8 3.7 SEQUENCE 12 2.0 3.7 3 23.0 20.2 2.8 3.7 4 23.0 20.2 2.9 3.7 5 23 .1 203 2.8 3.7 COLUMN AVERAGE 23.0 20.2 2.8 3.7 STANDARD DEV. 0.04 0.05 0.04 0.01 I COLUMN # II I I 2 I 3 I 4 I 5 I 6 I 7 I 33.2 29.2 4.0 53 2 33.2 28.9 4.3 53 SEQUENCE 13 2.0 5.3 3 33.2 29.3 3.9 5.3 4 33.2 28.7 4.4 5.3 ! 5 33.2 29.1 4.1 5.3 I COLUMN AVERAGE 33.2 29.0 4.1 5.3 0.04 0.23 0.23 0.01 STANDARD DEV. L I 8 I 1.5 1.5 1.5 1.5 1.5 1.5 0.01 I 8 I 3.2 3.2 33 3.2 33 3.2 0.01 I 8 I 4.7 4.6 4.7 4.6 4.7 4.7 0.04 Sample 10: I Project: B 1702069 Sheet NO.5 0f7 J .--.J 9 I 10 I OJ 0.00041 0.3 0.00051 OJ 0.00045 03 0.00040 03 0.00049 0.3 0.00045 0.01 0.00005 9 I 10 I 0.5 0.00234 0.5 0.00245 0.4 0.00244 0.5 0.00233 0.5 0.00234 0.5 0.00238 0.01 0.00006 9 I 10 I 0.7 0.00393 0.7 0.00410 0.6 0.00409 0.7 0.00392 0.7 0.00391 0.7 0.00399 0.04 0.00009 -.J L~ L--.J J -J II I 12 I 13 I 14 0.00083 0.00062 0.00011 13,686 0.00095 0.00073 0.00013 11,774 0.00089 0.00067 0.00012 12,675 0.00083 0.00062 0.00011 13,915 I 0.00095 0.00072 0.00013 11,666 0.00089 0.00067 0.00012 12,743 0.00006 0.00005 0.00001 1,045 II I 12 I 13 I 14 I 0.00258 0.00246 0.00044 7,387 0.00268 0.00257 0.00046 7,088 0.00268 0.00256 0.00046 7,118 0.00256 0.00245 0.00044 7,413 0.00258 0.00246 0.00044 7,423 0.00262 0.00250 0.00045 7,286 0.00006 0.00006 0.00001 168 II I 12 I 13 I 14 I 0.00411 0.00402 0.00072 6,526 0.00429 0.00419 0.00075 6,200 0.00428 0.00419 0.00075 6,308 0.00411 0.00402 0.00072 6,441 0.004 10 0.00401 0.00072 6,538 0.00418 0.00408 0.00073 6,402 0.00010 0.00009 0.00002 146 L L ,_ L L L L ------I ICOLUMN# II I I 2 I 3 I 4 I 5 I 6 I 7 I I 44.7 36.2 8.5 7.2 2 44.6 36.8 7.8 7.2 SEQUENCE 14 2.0 7.2 3 44.6 36.5 8.1 7.2 4 44.6 37.3 7.3 7.2 5 44.7 363 84 7.2 I I COLUMN AVERAGE 44.7 36.6 8.0 7.2 0.04 044 046 0.0 1 STANDARD DEV. I COLUMN # II I I 2 I 3 I 4 I 5 I 6 I 7 I 56.7 47.0 9.6 9.1 2 56.7 48.2 8.6 9.1 SEQUENCE 15 2.0 9.1 3 56.7 48.0 8.7 9.1 4 56.7 47.9 8.9 9.1 5 56.7 46.8 9.9 9.1 IQLUMN AVERAGE 56.7 47.6 9.1 9.1 0.03 0.60 0.59 0.01 STANDARD DEV. I 8 I 5.8 5.9 5.9 6.0 5.8 5.9 0.07 I 8 I 7.6 7.7 7.7 7.7 7.5 7.6 0.10 Sample ID: I Project: B 1702069 Sheet NO.6 of7 9 I 14 1.3 1.3 1.2 1.3 1.3 0.07 9 I L5 14 14 14 1.6 1.5 0.10 I --' L J '. -I 10 0.00547 0.00549 0.00523 0.00549 0.00548 0.00543 0.00011 10 0.00669 0.00704 0.00704 0.00672 0.00674 0.00685 0.00017 ~. I II I 12 0.00573 0.00560 0.00575 0.00562 0.00548 0.00536 0.00575 0.00562 0.00573 0.00560 0.00569 0.00556 0.00012 0.00011 I II I 12 0.00695 0.00682 0.00729 0.00716 0.00729 0.00716 0.00696 0.00684 0.00698 0.00686 0.00709 0.00697 0.00018 0.00018 Erik 1. Knudson Laboratory Technician J ) I 13 I 14 I 0.00100 5,821 0.00100 5,886 0.00096 6,134 0.00100 5,978 0.00100 5,830 0.00099 5,930 0.00002 \30 I 13 I 14 I 0.00122 6,202 0.00128 6,050 0.00128 6,024 0.00122 6,298 0.00123 6,136 0.00124 6,142 0.00003 112 L _ L L _ l L L --L -. J -J L-j ~-:-J ~-J Quick Shear Confining Pressure 4 PSI Peak Shear Stress (psi) = 44.2 I 50.00 45.00 40.00 35.00 30.00 r.;- '" c. '-' 25.00 '" '" CI> ... .... rn 20.00 / / ! 15.00 10.00 5.00 0.00 o / / / /V / 2 ~ -_._--- 3 0/0 Strain Sample ID: I Project: B 1702069 Sheet NO.7 of7 --~ ~ ~ 4 5 t-_-J -j 6 L L L J J J J J J j I Universal Model Calculations -US Customary Units Braun Sample 10: Project: B 1702069 Station: TP-4 Seq. Conf. Axial Stress Bulk Deviator Mr Pred. Mr Ln(Mr) Ln(Bulk) Ln(Dev) psi psi psi psi psi psi 1 6.0 2.1 20.1 1.8 13,615 16,232 9.519 3.003 0.563 2 6.0 4.0 22.0 3.4 12,277 12,263 9.415 3.093 1.233 3 6.0 5.7 23.7 4.9 11,016 10,688 9.307 3.166 1.598 4 6.0 8.1 26.1 7.1 10,062 9,465 9.217 3.263 1.959 5 6.0 10.1 28.1 8.9 10,024 8,828 9.213 3.336 2.187 6 4.0 2.1 14.1 1.8 13,319 13,025 9.497 2.645 0.569 7 4.0 4.0 16.0 3.5 9,445 10,061 9.153 2.772 1.239 8 4.0 5.9 17.9 5.2 8,595 8,818 9.059 2.884 1.640 9 4.0 7.8 19.8 6.9 8,200 8,112 9.012 2.987 1.932 10 4.0 9.8 21.8 8.7 8,468 7,672 9.044 3.084 2.161 I 11 2.0 1.8 7.8 1.5 12,743 9,796 9.453 2.052 0.418 12 2.0 3.7 9.7 3.2 7,286 7,662 8.894 2.272 1.178 13 2.0 5.3 11.3 4.7 6,402 7,026 8.764 2.428 1.540 14 2.0 7.2 13.2 5.9 5,930 6,853 8.688 2.578 1.773 15 2.0 9.1 15.1 7.6 6,142 6,534 8.723 2.714 2.034 l _ L l l L J '-L -J '.-J J Universal Model Calculations -US Customary Units Braun Sample ID: Project: B1702069 Station: TP-4 SUMMARY OUTPUT ax5 kl k2 k3 Value 3475.7918 0.606811974 -0.499551386 Regression Statistics t-Stat 32.43723 5.954231958 -7.74275784 Multiple R 0.918187299 R Square 0.843067917 R-sqr Adj . 0.8169126 Adjusted R Square 0.816912569 Std Err 0.1196666 or 12.71 % Standard Error 0.11966659 Observations 15 ANOVA df SS MS F Significance F Regression 2 0.923161964 0.461581 32.2331 1.49372E-05 Residual 12 0.171841114 0.0143201 Total 14 1.095003078 Coefficients Standard Error t Stat P-value Lower 95% Upper 95% Lower 95.0% Upper 95.0% Intercept 8.153577586 0.251364796 32.43723 4.661E-13 7.605900745 8.701254427 7.605900745 8.701254427 X Variable 1 0.606811974 0.10191272 5.954232 6.67E-05 0.384763232 0.828860715 0.384763232 0.828860715 X Variable 2 -0.49955139 0.064518534 -7.742758 5.246E-06 -0.640125196 -0.358977576 -0.640125196 -0.358977576 L L I J ) '_ -~J :.. J , --J Universal Model Graph -US Customary Units Braun Sample ID: I Project: B 1702069 Station: TP-4 1 I 18,000 16,000 0 14,000 ,~ r::---- -+-6 psi t---.. 12,000 " .~~ r----____ 4 psi c -.6:-2 psi ";;j I'-.... " 0 ':' 10,000 Do ~ "i- \;l ... 0 o Predicted 6 psi til - 0 o Predicted 4 psi .E := 8,000 ~ ---L .6. £ .6. Predicted 2 psi "0 0 -~ -6,000 4,000 2,000 0 0 2 3 4 5 6 7 8 9 10 Deviator Stress, psi . ) II I "_. J . J I ' I .-> I 1 ---.J Inland Pacific Engineering Company MOISTURE-DENSITY RELATIONSHIP Ie 3012 North Sullivan Road, Suite C Spokane Valley, WA 99216 Telephone: 509-209-6262 Fax: 509-290-5734 CLIENT NAI Black PROJECT NUMBER 16-2490 ~ 0.. (!J Z (!J Ui w o !z w ::;; w > Ci: ~ ...l I o W t-Z ~ o '" ~ '" ;::: z ~ (!J Ui w o t-Z W ::;; 'U c. w -;;: ~ a. -en en ...l Z :! w Io fil >-t-0::: ~ 0 a. 0 '" '" <'i '" iii t-u w 0 '" a. '" ;; '" en t-u w 0 '" 0.. u w 9, ., '" '" 0 "- ~ '? t-o (!J <Ii :5 en => 0 t-en t-Z (3 '" 0 t-u 0 '" ,;;5 130 125 120 115 110 105 100 95 90 85 80 75 0.. --0 u w a. \ 5 1\ -, \ 1\ 1\ 'I 1\ 'I \ \ \ 1\ \ 17 / I" 10 r\ \ ~ \ \ '\ \ \ \ ~ 1\ \ 1\ \ \\ \ 1\ \ \ 1\ \ \ \ \ \ y r----., • 15 PROJECT NAME Pro(1osed Street Im(1rovements PROJECT LOCATION S(1okane Valle:i, WA Sample ID TP-4 Description of Material SILTY SAND(SM) Test Method ASTM 01557 Method A 1\ 1\ TEST RESULTS 1\ \ 1\ Maximum Dry Density 104.0 PCF \ \ Optimum Water Content 13.5 % \ i\ \ \ i\ \ A TTERBERG LIMITS \ 1\ 1\ \ 1\ i\ LL PL PI 1\ [\ ------ r\ \ \ 1\ 1\ '\ Curves of 100% Saturation 1\ 1\ for Specific Gravity Equal to: 1\ 1\ 11\ \ 2.80 '\. \. \ 1\ 2.70 \.. '\ 1\ \ 2.60 '\ 1\ 1\ 11\ \.. '\. 1\ 1\ '\ '\ 1,\ 1,\ I'\. '\ I'. I'\. '\ 1"\ "\ '\ 1,\ '\ I": " '" '\ '" '\, '" I"-.J "l 20 25 30 35 40 45 WATER CONTENT, % i I L l L Re~ilient Modulus Testing -AASHTO T307 US Customary Units Date: April 10,2017 Client: Inland Pacific Engineering Company Paul Nelson P.O. Box 1566 Veradale, WA 99037 Sample Information Braun Sample 10.1 File Name: Sample Type: Test Date: Comments' COLUMN # I Chamber Confining PARAMETER Pressure DESIGNATION S3 UNIT psi PRECISION SEQUENCE 1 6.0 Type 2 06-Apr-20 17 Spokane Valley. WA 2 3 Nominal Cycle Maximum No. Axial Stress Scyclic cl psi --- - I 2 2.3 3 4 5 I COLUMN AVERAGE STANDARD DEV. Sample Diameter, in.: Sample I-leight, in.: Desired M.e., %: Desired Dry Density., pcf: 4 5 6 7 Actual Actual Actual Actual Applied Applied Applied Applied Maximum Cyclic Contact Maximum Axial Load Load Axial Load Stress Pmax Pcyclic Pcontact Smax Ibs. Ibs. Ibs. psi 14.2 11.8 2.4 2.3 14.3 11.9 2.3 2.3 14.2 11.8 2.4 2.3 14.2 11.8 2.4 2.3 14.2 11.8 2.5 2.3 14.2 11 .8 2.4 2.3 0.02 0.07 0.05 0.00 2.80 5.51 14.3 104.7 8 Actual Applied Cyclic Stress Scyclic psi 1.9 1.9 1.9 1.9 1.9 1.9 0.01 J 9 10 Actual Recov Def. Applied LVDTI Contact Reading Stress Scontact HI psi inches 0.4 0.00049 0.4 0.00052 0.4 0.00051 0.4 0.00047 0.4 0.00050 0.4 0.00050 0.01 0.00002 J J Project: B 1702069 Project Description: Resilient Modulus Test AASHTOT307 Client 10: Station: Proposed Street Improvements TP-7 Sample M.C., % before, after: Sample Dry Den., pcf: Failed in Shear?: Triaxial Shear Strength, psi' II 12 Recov Dcf. Average LVDT2 Recov Def. Reading LVDT I and LVDT 2 H2 H average inches inches 0.00052 0.00051 0.00057 0.00054 0.00056 0.00053 0.00051 0.00049 0.00055 0.00053 0.00054 0.00052 0.00002 0.00002 14.7,14.2 106.1 YES 45.3 13 Resilient Strain in/in 0.00009 0.00010 0.00010 0.00009 0.00010 0.00009 0.00000 14 Resilient Modulus Mr psi --- 21 ,081 19,724 19,921 21 ,508 20,044 20,456 789 L L l L I II I I I I I I I COLUMN # 1 2 3 4 5 6 7 1 26.5 22.8 3.7 4.3 2 26.5 22.9 3.6 4.3 SEQUENCE 2 6.0 4.3 3 26.5 22.8 3.7 4.3 4 26.4 22.8 3.6 4.3 5 26.3 22.7 3.6 4.3 I I COLUMN AVERAGE 26.4 22.8 3.6 4.3 0.07 0.06 0.07 0.01 STANDARD DEV. I COLUMN # II 1 I 2 I 3 I 4 I 5 I 6 I 7 1 38.3 33.5 4.8 6.2 2 38.3 33.4 4.9 6.2 SEQUENCE 3 6.0 6.2 3 38.3 33.5 4.8 6.2 4 38.4 33.6 4.8 6.2 5 38.5 33.6 4.9 6.2 COLUMN AVERAGE 38.4 33.5 4.8 6.2 STANDARD DEY. 0.08 0.08 0.04 0.01 I COLUMNfI II 1 I 2 I 3 I 4 I 5 I 6 I 7 1 51.1 45.2 5.9 8.3 2 51.2 45.2 6.0 8.3 SEQUENCE 4 6.0 8.3 3 51.1 45.2 6.0 8.3 4 51.2 45.3 5.8 8.3 5 51.1 45.2 5.9 8.3 COLUMN AVERAGE 51.2 45.2 5.9 8.3 STANDARD DEV. 0.04 0.06 0.07 0.01 I 8 I 3.7 3.7 3.7 3.7 3.7 3.7 0.01 I 8 I 5.4 5.4 5.4 5.4 5.4 5.4 0.01 I 8 I 7.3 7.3 7.3 7.3 7.3 7.3 0.01 Sample ID: 1 Project: B 1702069 Sheet No.2 of7 9 0.6 0.6 0.6 0.6 0.6 0.6 0.01 9 0.8 0.8 0.8 0.8 0.8 0.8 0.01 9 1.0 1.0 1.0 0.9 1.0 1.0 0.01 J ~ -..l I 10 I 11 0.00104 0.00112 0.00100 0.00107 0.00099 0.00107 0.00099 0.00107 0.00095 0.00102 0.00099 0.00107 0.00003 0.00004 I 10 I 11 0.00165 0.00180 0.00150 0.00164 0.00157 0.00172 0.00157 0.00172 0.00156 0.00171 0.00157 0.00172 0.00007 0.00008 I 10 I 11 0.00218 0.00237 0.00217 0.00237 0.00227 0.00247 0.00216 0.00235 0.00226 0.00246 0.00221 0.00240 0.00005 0.00006 -.J J ----I 12 I 13 I 14 I 0.00108 0.00020 18,948 0.00103 0.00019 19,938 0.00103 0.00019 19,878 0.00103 0.00019 19,906 0.00099 0.00018 20,678 0.00103 0.00019 19,870 0.00003 0.00001 614 I 12 I 13 I 14 I 0.00173 0.00031 17,453 0.00157 0.00028 19,131 0.00164 0.00030 18,362 0.00165 0.00030 18,344 0.00164 0.00030 18,434 0.00165 0.00030 18,345 0.00008 0.00001 596 I 12 I 13 I 14 I 0.00227 0.00041 17,902 0.00227 0.00041 17,907 0.00237 0.00043 17,140 0.00226 0.00041 18,047 0.00236 0.00043 17,232 0.00231 0.00042 17,645 0.00005 0.00001 425 L -r L L __ L L L _ , I COLUMN # II 1 I 2 I 3 I 4 I 5 I 6 I 7 1 63.5 55.7 7.8 10.3 I 2 63 .5 56.3 7.2 10.3 ~EQUENCE 5 6.0 10.3 3 63.3 56.4 6.9 10.3 4 63.6 56.5 7.1 10.3 5 63.4 55.7 7.7 10.3 I I COLUMN AVERAGE 63.5 56.1 7.3 10.3 0.10 0.37 0.39 0.02 STANDARD DEV. I COLUMN # II 1 I 2 I 3 I 4 I 5 I 6 I 7 1 13.2 11.2 1.9 2.1 2 13.2 11.2 2.0 2.1 SEQUENCE 6 4.0 2.1 3 13.2 11.2 2.0 2.1 4 13.2 11.3 1.9 2.1 5 13.2 11.2 2.0 2.1 COLUMN AVERAGE 13.2 11.2 2.0 2.1 STANDARD DEV. 0.02 0.04 0.04 0.00 I COLUMN # II 1 I 2 I 3 I 4 I 5 I 6 I 7 1 25.6 22.3 3.4 4.2 2 25.6 22.2 3.4 4.1 SEQUENCE 7 4.0 4.1 3 25.6 22.5 3.1 4.2 4 25.5 22.2 3.3 4.1 5 25.6 22.5 3.1 4.1 COLUMN AVERAGE 25.6 22.3 3.3 4.1 STANDARD DEV. 0.04 0.16 0.15 0.01 I 8 I 9.0 9.1 9.1 9.1 9.0 9.1 0.06 I 8 I 1.8 1.8 1.8 1.8 1.8 1.8 0.01 I 8 I 3.6 3.6 3.6 3.6 3.6 3.6 0.03 Sample 10: 1 Project: B 1702069 Sheet No.3 of7 9 I 10 I 1.3 0.00279 1.2 0.00291 1.1 0.00278 1.2 0.00292 1.3 0.00295 1.2 0.00287 0.06 0.00008 9 I 10 I 0.3 0.00046 0.3 0.00042 0.3 0.00040 0.3 0.00042 0.3 0.00046 0.3 0.00043 0.01 0.00002 9 I 10 I 0.5 0.00109 0.6 0.00108 0.5 0.00108 0.5 0.00107 0.5 0.00113 0.5 0.00109 0.03 0.00002 '--~ J 11 I 12 I 13 I 14 I 0.00305 0.00292 0.00053 17,171 0.00319 0.00305 0.00055 16,615 0.00304 0.00291 0.00053 17,403 0.0031 9 0.00306 0.00055 16,605 0.00322 0.00308 0.00056 16,264 0.00314 0.00300 0.00054 16,812 0.00008 0.00008 0.00001 464 11 I 12 I 13 I 14 I 0.00056 0.00051 0.00009 19,788 0.00052 0.00047 0.00009 21,408 0.00051 0.00046 0.00008 22,194 0.00052 0.00047 0.00009 21,464 0.00057 0.00051 0.00009 19,655 0.00054 0.00048 0.00009 20,902 0.00003 0.00003 0.00000 1,122 11 I 12 I 13 I 14 I 0.00117 0.00113 0.00020 17,677 0.0011 6 0.00112 0.00020 17,900 0.00116 0.0011 2 0.00020 18,068 0.00115 0.00111 0.00020 18,003 0.00121 0.00117 0.00021 17,291 0.00117 0.00113 0.00020 17,788 0.00002 0.00002 0.00000 315 i L L L L L ~ L -J J 1 'COLUMN # II 1 1 2 1 3 1 4 1 5 1 6 --1-7--1 8 1 9---Tn 10 1 11 1 12 1 13 1 14 1 37.7 33.4 4.3 6.1 5.4 0.7 0.00184 0.00196 0.00190 0.00034 15,850 2 37.8 33.5 4.3 6.1 5.4 0.7 0.00174 0.00186 0.00180 0.00033 16,722 SEQUENCE 8 4.0 6.1 3 37.7 33.6 4.1 6.1 5.4 0.7 0.00184 0.00196 0.00190 0.00034 15,865 4 37.8 33.2 4.6 6.1 5.4 0.7 0.00167 0.00178 0.00173 0.00031 17,283 5 37.8 33.8 4.1 6.1 5.5 0.7 0.00168 0.00179 0.00174 0.00031 17,479 I I COLUMN AVERAGE 37.8 33.5 4.3 6.1 5.4 0.7 0.00175 0.00187 0.00181 0.00033 16,640 STANDARD DEV. 0.05 0.22 0.20 0.01 0.04 0.03 0.00008 0.00009 0.00008 0.00002 766 1 COLUMN # II 1 1 2 1 3 1 4 1 5 1 6 1 7 1 8 1 9 1 10 1 11 1 12 1 13 1 14 I 1 49.8 44.2 5.6 8.1 7.2 0.9 0.00247 0.00261 0.00254 0.00046 15,656 2 49.9 44.3 5.6 8.1 7.2 0.9 0.00249 0.00263 0.00256 0.00046 15,588 SEQUENCE 9 4.0 8.1 3 50.0 44.3 5.7 8.1 7.2 0.9 0.00247 0.00261 0.00254 0.00046 15,672 4 49.9 43 .9 6.0 8.1 7.1 1.0 0.00249 0.00263 0.00256 0.00046 15,404 5 49.9 44 .2 5.7 8.1 7.2 0.9 0.00248 0.00262 0.00255 0.00046 15,577 COLUMN AVERAGE 49.9 44 .2 5.7 8.1 7.2 0.9 0.00248 0.00262 0.00255 0.00046 15,579 STANDARD DEV. 0.09 0.17 0.17 0.01 0.03 0.03 0.00001 0.00001 0.00001 0.00000 107 1 COLUMN # II 1 1 2 1 3 1 4 1 5 1 6 1 7 1 8 1 9 1 10 1 11 1 12 1 13 1 14 1 1 61.1 54.6 6.5 9.9 8.8 1.0 0.00320 0.00340 0.00330 0.00060 14,869 2 60.6 53.2 7.4 9.8 8.6 1.2 0.00298 0.00317 0.00308 0.00055 15,573 SEQUENCE 10 4.0 10.0 3 62.2 55.2 7.0 10.1 8.9 1.1 0.00317 0.00338 0.00328 0.00059 15,159 4 62.0 54.7 7.3 10.0 8.9 1.2 0.00301 0.00321 0.00311 0.00056 15,843 5 62.1 54.8 7.4 10.1 8.9 1.2 0.00331 0.00352 0.00342 0.00062 14,431 COLUMN AVERAGE 61.6 54.5 7.1 10.0 8.8 1.1 0.00314 0.00334 0.00324 0.00058 15,175 STANDARDDEV. 0.72 0.74 0.38 0.12 0.12 0.06 0.00014 0.00014 0.00014 0.00003 560 Sample ID: I Project: B 1702069 Sheet No.4 of7 L l __ L L L_ L L_ L _ J L I COLUMN II II 1 I 2 I 3 I 4 I 5 I 6 I 7 1 12.0 10.4 1.6 2.0 I 2 12.0 10.4 1.6 1.9 SEQUENCE 11 1.9 1.9 3 12.0 10.3 1.7 1.9 4 12.0 10.3 1.7 1.9 5 12.0 10.4 1.6 2.0 I I COLUMN AVERAGE 12.0 10.4 1.7 1.9 0.02 0.06 0.05 0.00 STANDARD DEV. I COLUMN II II I I 2 I 3 I 4 I 5 I 6 I 7 I 24.1 213 2.8 3.9 2 24.0 21.3 2.7 3.9 SEQUENCE 12 2.0 3.9 3 24.1 21.2 2.9 3.9 4 24.1 21.2 2.9 3.9 5 24.0 21.2 2.8 3.9 COLUMN AVERAGE 24.1 21.2 2.8 3.9 STANDARD DEV. 0.04 0.06 0.07 0.01 I COLUMN II II I I 2 I 3 I 4 I 5 I 6 I 7 I 35.9 32.2 3.8 5.8 2 35.9 31.9 4.0 5.8 SEQUENCE 13 2.0 5.8 3 35.9 32.3 3.6 5.8 4 36.0 32.3 3.7 5.8 5 35.9 32.0 3.9 5.8 COLUMN AVERAGE 35.9 32.1 3.8 5.8 STANDARD DEV. 0.04 0.18 0.16 0.01 J I 8 I 1.7 1.7 1.7 1.7 1.7 1.7 0.01 I 8 I 3.4 3.5 3.4 3.4 3.4 3.4 0.0 1 I 8 I 5.2 5.2 5.2 5.2 5.2 5.2 0.03 Sample ID: I Project: B 1702069 Sheet NO.5 of? 9 0.3 0.3 OJ 0.3 0.3 OJ 0.01 9 0.5 0.4 0.5 0.5 0.4 0.5 0.01 9 0.6 0.7 0.6 0.6 0.6 0.6 0.03 l-_J l_ J I 10 I 11 I 0.00028 0.00059 0.00032 0.00063 0.00028 0.00060 0.00025 0.00055 0.00028 0.00059 0.00028 0.00059 0.00002 0.00003 I 10 I II I 0.00130 0.00137 0.00130 0.00137 0.00131 0.00138 0.00131 0.00138 0.00119 0.00126 0.00128 0.00135 0.00005 0.00005 I 10 I II I 0.00212 0.00223 0.00204 0.00214 0.00213 0.00224 0.00213 0.00224 0.00203 0.00214 0.00209 0.00220 0.00005 0.00005 J J 12 I 13 I 14 0.00043 0.00008 21,647 0.00047 0.00009 19,828 0.00044 0.00008 21,125 0.00040 0.00007 23,217 0.00044 0.00008 21,354 0.00044 0.00008 21,434 0.00002 0.00000 1,215 12 I 13 I 14 I 0.00134 0.00024 14,305 0.00134 0.00024 14,336 0.00134 0.00024 14,185 0.00134 0.00024 14,196 0.00123 0.00022 15,568 0.00132 0.00024 14,518 0.00005 0.00001 591 12 I 13 I 14 I 0.00217 0.00039 13,293 0.00218 0.00038 13,745 0.00218 0.00039 13,317 0.00218 0.00039 13,323 0.00209 0.00038 13,800 0.00216 0.00039 13,496 0.00004 0.00001 254 L l L ~ L L I COLUMN # II I I 2 I 3 I 4 I 5 I 6 I 7 I 48.1 40.2 7.8 7.8 2 48.0 41.5 6.5 7.8 SEQUENCE 14 2.0 7.8 3 48.1 41.4 6.7 7.8 4 48.0 39.9 8.1 7.8 5 48.1 41.3 6.8 7.8 I I COLUMN AVERAGE 48.0 40.9 7.2 7.8 0.03 0.72 0.72 0.01 STANDARD DEV I COLUMN # II I I 2 I 3 I 4 I 5 I 6 I 7 I 60.3 50.9 9.4 9.8 2 60.2 51.1 9.2 9.8 SEQUENCE 15 2.0 9.8 3 60.3 51.9 8.4 9.8 4 60.2 52.4 7.8 9.8 5 60.3 52.1 8.2 9.8 COLUMN AVERAGE 60.2 51.7 8.6 9.8 STANDARD DEV. 0.04 0.67 0.67 0.01 .J I 8 I 6.5 6.7 6.7 6.5 6.7 6.6 0.12 I 8 I 8.2 8.3 8.4 8.5 8.5 8.4 0.11 Sample 10: I Project: B 1702069 Sheet No.6 of7 9 I 10 1.3 0.00287 l.l 0.00287 l.l 0.00300 1.3 0.00286 1.1 0.00300 1.2 0.00292 0.12 0.00007 9 I 10 1.5 0.00352 1.5 0.00351 1.4 0.00352 1.3 0.00384 1.3 0.00369 1.4 0.00362 0.11 0.00014 J J I II I 12 I 0.00301 0.00294 0.00300 0.00293 0.00314 0.00307 0.00299 0.00293 0.00314 0.00307 0.00305 0.00299 0.00008 0.00007 II I 12 0.00369 0.00361 0.00367 0.00359 0.00369 0.00361 0.00402 0.00393 0.00387 0.00378 0.00379 0.00370 0.00015 0.00015 Erik J. Knudson Laboratory Technician _J I 13 I 14 0.00053 12,301 I 0.00053 12,736 0.00055 12,131 0.00053 12,280 0.00055 12,089 0.00054 12,307 0.00001 257 I 13 I 14 I 0.00065 12,699 0.00065 12,792 0.00065 12,940 0.00071 11 ,985 0.00068 12,409 0.00067 12,565 0.00003 378 L QJick Shear ( L-L L L J J :-j Confining Pressure 4 PSI Peak Shear Stress (psi) = 45.3 i 50.00 45.00 40.00 35.00 30.00 :=-til c. ';;;" 25.00 til Qj ... ... rn 20.00 15.00 10.00 5.00 / / / II 0.00 o / -- / / / / 2 3 % Strain Sample 10: I Project: B 1702069 Sheet No.7 of7 -~ 4 5 r_ J J ~ 6 L L L_ L~ L L J L-J L-J L _J _' _J _._J Universal Model Calculations -US Customary Units Braun Sample ID: Project: B 1702069 Station: TP-7 Seq. Conf. Axial Stress Bulk Deviator Mr Pred. Mr Ln(Mr) Ln(Bulk) Ln(Dev) psi psi psi psi psi psi I 6.0 2.3 20 .3 1.9 20,456 23 ,592 9.926 3.01 I 0.650 2 6.0 4.3 22.3 3.7 19,870 19,613 9.897 3.104 1.307 3 6.0 6.2 24.2 5.4 18,345 17,768 9.817 3.187 1.692 4 6.0 8.3 26 .3 7.3 17,645 16,552 9.778 3.269 1.992 5 6.0 10.3 28.3 9.1 16,812 15,799 9.730 3.342 2.208 6 4.0 2.1 14.1 1.8 20,902 21 ,278 9.948 2.649 0.598 7 4.0 4.1 16.1 3.6 17,788 17,740 9.786 2.782 1.287 8 4.0 6.1 18.1 5.4 16,640 16,138 9.720 2.897 1.692 9 4.0 8.1 20.1 7.2 15,579 15,250 9.654 3.000 1.969 I 10 4.0 10.0 22.0 8.8 15,175 14,667 9.627 3.090 2.178 11 1.9 1.9 7.7 1.7 21,434 17,875 9.973 2.047 0.519 12 2.0 3.9 9.9 3.4 14,518 15,326 9.583 2.293 1.236 13 2.0 5.8 11.8 5.2 13,496 14,194 9.510 2.470 1.650 14 2.0 7.8 13.8 6.6 12,307 13,802 9.418 2.623 1.890 15 2.0 9.8 15.8 8.4 12,565 13,363 9.439 2.758 2.125 l L L , L L L LJ Universal Model Calculations -US Customary Units Braun Sample ID: I Station: TP-7 SUMMARY OUTPUT ax5 kl k2 Value 10724.224 0.332780325 Reflression Statistics t-Stat 51.11372 4.526286657 Multiple R 0.897916763 R Square 0.806254513 R-sqr Adj. 0.7739636 Adjusted R Square 0.773963599 Std Err 0.0855097 or 8.93% Standard Error 0.085509723 Observations 15 ANOVA df SS MS F Significance F Regression 2 0.365134451 0.1825672 24.968463 5.28919E-05 Residual 12 0.087742953 0.0073119 Total 14 0.452877404 Coefficients Standard Error t Stat P-value Lower 95% Intercept 9.28026037 0.181561043 51.11372 2.065E-15 8.884672839 X Variable 1 0.332780325 0.073521708 4.5262867 0.0006942 0.172590285 X Variable 2 -0.32833968 0.046837238 -7.010227 1.414E-05 -0.430389258 --1 .J J J J J Project: Bl702069 k3 -0.328339683 -7.010227266 Upper 95% Lower 95.0% Upper 95.0% 9.675847901 8.884672839 9.675847901 0.492970365 0.172590285 0.492970365 -0.226290108 -0.430389258 -0.226290108 L L l L Universal Model Graph -US Customary Units Braun Sample ID: Station: TP-7 1 26,000 24,000 22,000 20,000 • ~ 18,000 ~ - .-16,000 til ':' 14,000 til .; 12,000 "0 o 10,000 ~ 000 8, 6,000 4,000 2,000 0 0 2 3 4 5 Deviator Stress, psi '-~1 ~ ti 7 r--l ---' r-) ~ 8 9 ,~ ~ , J ----, --l Project: B 1702069 --+-6 psi __ 4 psi --..-2 psi o Predicted 6 psi o Predicted 4 psi /:;. Predicted 2 psi I J J .. J l .J J 1 J J ) J r- ...J Inland Pacific Engineering Company MOISTURE-DENSITY RELATIONSHIP C 3012 North Sullivan Road, Suite C Spokane Valley, WA 99216 Telephone: 509-209-6262 Fax: 509-290-5734 CLIENT NAI Black PROJECT NUMBER 16-249D ..., a. (!) z (!) iii LU o I-Z LU :;; LU ~ a. a) ...J ...J I o LU ~ ~ o m ..,. N >D ~ ~ (!) iii LU o ~ LU ::;; LU ~ a) ...J ...J ..... u c. ~ U5 z LU 0 I o LU >-z cc <: 0 t- a. o m ..,. ~ iii t-u LU (3 a: a. <0 ;; N iii I-u LU (3 a: a. u LU !!: '-; ..,. '" i:i r-- £:! '? I-0 (!) oj :s a) ::J 0 I-a) I-Z (3 a: 0 I-u 0 a: a. U LU !!: 135 130 125 120 115 110 105 100 95 90 85 80 75 0 5 - 1\ \ 1\ \ '\ r\ 1\ \ 1\ \ '\ \ \ \ / 10 \ "' \ 1\ "\ \ r\ \ '\ 1\ 1\ \ 1\ \ \ 1\ \ \ 1\ \ \ \ \ 1\ '" I. 15 PROJECT NAME Prol2osed Street Iml2rovements PROJECT LOCATION Sl20kane Valley, WA Sample 10 TP-7 Description of Material SANDY LEAN CLAY(CL) Test Method ASTM 01557 Method A 1\ \ 1\ TEST RESULTS 1\ \ \ Maximum Dry Density 110.2 PCF 1\ \ Optimum Water Content 14.3 % \ ~ \ \ 1\ \ A TIER BERG LIMITS \ \ 1\ \ " 1\ LL PL PI 1\ 1\ ------ 1\ \ \ 1\ 1\ \ Curves of 100% Saturation 1\ " for Specific Gravity Equal to: \ f\ 1\ '\ 2.80 f\ '\ \ '\ 2.70 f\ \ '\ \ 2.60 \ \ \ \ 1\ 1\ \ 1,\ "- 1\ '\ \ I\. 1"'-1\ I\. '\ I" '\ 1"\ " 1"'-"- I'\" " "" '\ r":: '\ "" '\ N '\1 20 25 30 35 40 45 WATER CONTENT, % --_ .. .. I • J l -, August 21,2017 Project No. 16-249A NAI Black c/o Mr. Bryan Walker 107 South Howard Suite 500 Spokane, WA 99201 I E Inland Pacific Engineering Company Geotechnical Engineering and Consulting Re: Full-Scale Drywell Testing Proposed Stormwater Management Facility 4403 South Dishman-Mica Road Spokane Valley, WA Dear Mr. Walker: As you authorized, we have completed a full-scale drywell test on the drywell installed at the above-referenced site in Spokane Valley, Washington. The purpose of the testing was to establish a design flow rate. This report summarizes the results of our site investigation, engineering analyses and recommendations. AVAILABLE INFORMATION We were provided a topographic survey for the project site by Whipple Consulting Engineers, Inc. (WCE). This topographic survey showed the existing roadways, existing structures, property lines, and existing ground surface elevation contours. This plan was prepared by WCE and was dated November 7,2013. The site was used as a golf course prior to our evaluation. The site is relatively level with some elevated golf greens and excavated areas for water hazards. The site is primarily grass-covered with scattered trees along the fairways and pine trees in the undeveloped area to the northwest. The clubhouse building is present at the southwest comer. In addition, we performed a preliminary geotechnical evaluation for the property in December 2013. The results of that evaluation, along with our opinions and recommendations, are summarized in our Preliminary Geotechnical Evaluation dated December 31, 2013. P.O. Box 1566, Veradale, WA 99037 Phone 509-209-6262 I J l 1 I -J Full-Scale Drywell Testing Painted Hills Golf Course Spokane Valley, WA Inland Pacific Engineering Company Project No. 16-249A 4403 South Dishman-Mica Road August 21, 2017 Page 2 We also performed a geotechnical evaluation for certification of the existing levee along Chester Creek in April 2014. The results of that evaluation are summarized in our Geotechnical Evaluation report dated February 12,2015. Lastly, we perfOlmed a geotechnical evaluation in July 2015 consisting often 50-foot borings in the south half of the property. The results of that evaluation are summarized in our Geotechnical Evaluation Phase 2 report dated July 23 ,2015. FIELD EVALUATION A geotechnical engineer from Inland Pacific Engineering Company (IPEC) perfOlmed a full-scale drywell test on the Type 2 drywell (double depth) on May 6, 2016. The drywell test was performed in accordance with the Spokane Regional Stormwater Manual, Appendix 4B procedures. The drywell was installed at the location shown on Figure 3 (attached). ANALYSIS AND RECOMMENDATIONS We calculated a design outflow rate for the existing drywell using the results of the recent and previous laboratOlY tests and the procedures described in the SRSM manual, Appendix 4B (Full- Scale Drywell Test Method). Based on the test performed, we recommend using a design flow rate of 1.05 cfs for design. This recommended design outflow rate includes a safety factor of 1.1 as required by the SRSM. Attached are our calculations for the design outflow rate. If additional dtywell baITe1s are added, the safety factor increases. REMARKS This report is for the exclusive use of the addressee and the copied parties to use in design of the proposed project and to prepare construction documents. In the absence of our written approval, we make no representations and assume no responsibility to other paI1ies regarding this report. The data, analyses, and recommendations may not be appropriate for other structures or purposes. We recommend that parties contemplating other structures or purposes contact us. Services performed by the geotechnical engineers for this project have been conducted in a manner consistent with that level of care ordinarily exercised by members of the profession currently practicing in this area under similar budget and time restraints. No wan'anty, expressed or implied, is intended or made. 1 -, I ....J J Full-Scale Drywell Testing Painted Hills Golf Course Spokane Valley, WA Inland Pacific Engineering Company GENERAL REMARKS Project No. 16-249A 4403 South Dishman-Mica Road August 21,2017 Page 3 It has been a pleasure being of service to you for this project. If you have any questions or need additional information, please do not hesitate to call me at (509) 209-6262 at your convenience. Sincerely, Inland Pacific Engineering Company Paul T. Nelson, P.E. Principal Engineer Attachments: Figure 1, Site Location Map Figure 2, NRCS Map Figure 3, Drywell Location Map Laboratory Test Results Full-Scale Drywell Test Results Design Flow Rate Calculations l J I --' IPEC Inland Pacific Engineering Company Geotechnical Engineering and Consultmg FIGURE 1 Site Location Map Project No. 16-249A Painted Hills Golf Course 4403 South Dishman-Mica Road June 28,2016 Spokane County, WA J I J J 1 J IPEC: Inland Pacific Engineering Company Geotechnical Engineering and Consulting FIGURE 2 NRCSMap Project No. 16-249A Painted Hills Golf Course 4403 South Dishman-Mica Road June 28,2016 Spokane County, WA J l l -, I s.~~:~ .r.-' ---1 J' " FIGURE 3 RlW~!IXItJ:24 ---------,-" E-111B1.Z' ". " ,.' .~ ~ '. '. \, , ... -;~ J J J I I, 1. , I. 1, ." IPEC . ------~- Inland Pacific Engineering Company Geotechnical Engineering and Consulring Drywe I _ ........... . 'eH Boring Location Map Project No. 16-249A Painted Hills Golf Course August 21,2017 4403 South Dishman-Mica Road Spokane County, WA l I "I j I J J 1 -' J J Inland Pacific Engineering Company GRAIN SIZE DISTRIBUTION C 3012 North Sullivan Road, Suite C Spokane Valley, WA 99216 Telephone: 509-209-6262 Fax: 509-290-5734 CLIENT NAI Black PROJECT NAME Painted Hills Drvwell Test PROJECT NUMBER 16-249A PROJECT LOCATION 4403 South Dishman-Mica Road u.s. SIEVE OPENING IN INCHES I U.S. SIEVE NUMBERS I HYDROMETER ...., 0.. (9 tii UJ .... ...J ...J UJ ~ o en ...J ...J :x: o UJ .... Z ~ ~ r1i '" ;:: z § (9 z !;i UJ .... ...J ...J UJ ~ a: o en ...J ...J I o UJ .... Z ~ ...: .. ot '" iii .... u UJ (3 a: 0.. '" C; N iii .... u l-I (9 iIi S >-[lJ 0: UJ z u::: I-z UJ U 0: UJ (L 6 4 3 100 I 95 90 85 80 : 75 70 65 : 60 : 55 50 45 : : 40 35 30 : 25 20 15 : 10 5 0 100 I UJ COBBLES (3 I a: 0.. u UJ BOREHOLE OEPH 9, .,.; -:. L16·057 20.0 N '" on ~ ;0 fll ~ 0 (9 ai 5 BOREHOLE OEPH en ::> ~. L16-057 20.0 en .... z (9 .;, N en z ...: a: (9 1.5 1 314 112318 3 4 6 810 1416 20 30 40 50 60 100140200 f" ~i I II I I I I I I : \: • : : i\ : : : \: : • : : : \ \ \ : \ : : \ : ~ : : \ : \ : \ : : : ~ 10 1 0.1 0.01 GRAIN SIZE IN MILLIMETERS GRAVEL I SAND SILT OR CLAY coarse I fine I coarse medium fine Classification LL PL PI SP Poorly Graded Sand with Gravel 0100 060 030 010 %Gravel %Sand %Silt 50 5.212 2.167 0.904 42.9 53.6 0.001 Cc Cu 1.00 5.76 %Clay 3.5 l --1 -.J J J IPEC Inland Pacific Engineering Company Geotechnical Engineering and Consulting Full-Scale Drywell Test Results Project Name: ___ ...:P..;;.a:::in"'-'t;;...ed::...:c:H:::il:::ls...:D"-'ry"'-w...:e"'"'ll-'T:....:ec.:.st~ __ Test Date: 5/6/2016 Project Number: ______ ....;1...;.6..;;.-2_4"'9;;...A'--____ _ Test Location: Existing Drywell Client: ______ N_A_I_B_la_c_k _____ _ Depth: 20' Elapsed Depth to Time Time Water (seconds) (feet) 10:00 0 19.5 11:00 3600 18.2 11:10 600 18.2 11:20 600 18.2 11 :30 600 18.2 11:35 18.3 11 :40 18.6 11 :45 19.1 11 :50 19.5 Depth to Water (feet) 20.0 - 18.0 I 17.5 .." ... .." . .." ... ..".. . .." ... ..,,-' .." ... .." ... .." ... Flow Meter Reading (fe) 596.6 1171.5 1261.0 1350.7 1441.1 Volume of Water Flow Rate (cfs) (fe) 574.90 1.60E-Ol 89.50 1.49E-Ol 89.70 l.50E-01 90.40 1.51E-Ol Average Flow Rate: 1.50E-OI 1.62E-Ol 1.60E-01 1.58E-01 1.S6E-01 1.54E-Ol 1.52E-01 1.S0E-01 1.48E-Ol 1.46E-Ol 1.44E-Ol Flow Rate (cfs) 1.42E-Ol +----------r----- 11:00 11:10 P.O. Bo, 1.:'6(1. '·('mel.lIe. \\ '900~7 Phone: .:'U\)-109-6262 11:20 11:30 ~Flow Rate (cfs) -', l .J ------ o r j\/l ~ ,'; 7.-e-J ~ 0.-~~ <J r~·.", {;A l Q~51~JJII;2-ecJ. JJ(gcv ~k ,+A~-!--esT I I ::; Ie II re I () ,-P tv q.ii!?/ ~ rv ~ N-y LV e i ( H ~ (YI CJ ){.; v1Il (.e,.~ ~,p I 't ell' (.,J e-i i ~ I '\ (lolk-~~/' d~uJJ!e der ;~ a::;: !/ / o() ~ -P.s H= )F ':! ~ He -[0 o. -' rlt -- 2:.1::0(1 7)) c-/~r _c -fs __ , ~( ~d:e.r 'Vle (J e <~d '-'\. OOl-I -0 D'.) r ct;{cp ( ~ Ii ) &~ r(;b!e-4 [? -{ ~r:J.., 3~ S Z f c;t5' ~~:J ~o ~~-E: ifeS ~ I , ( /10 = J, DS e;:C-S ~- , IPEC Inland Pacific Engineering Company NAM E.oF PROJ~CT l " ./ 1 •• -" SHEET NUMBER --Geotechni cal Engineering and ConSUllinf! ,. '-... H f!( t: "" ~k ... J~. I _ ~,...-r ..... ., I-.:.f I? ~::. ! { >" ' OF ~C~OM~PU~TE~D~BY~~C~HE~CK~~B~y ~rJO=B~NU~M~BE-R --~DA-TE~~~-J P.O. Box 1566. Veradale. WA 99037 Phone 509-209-6262 /~f/l.,."'/ /Uft" ~ I b --2 t.../ ,. A -). /-! f..R -I August 22, 2017 Project No. 16-249A NAI Black c/o Mr. Bryan Walker 107 South Howard Suite 500 Spokane, W A 99201 Inland Pacific Engineering Company Geoteclmical Engineering and Consulting Re: Addendum to Full-Scale Drywell Testing Proposed Stormwater Management Facility 4403 South Dishman-Mica Road Spokane Valley, WA Dear Mr. Walker: As you authorized, we have completed a full-scale drywell test on the drywell installed at the above-referenced site in Spokane Valley, Washington. The purpose ofthe testing was to establish a design flow rate. This addendum provides our recommendations for a design infiltration rate for proposed gravel galleries between the drywells. AVAILABLE INFORMATION We were provided a topographic survey for the project site by Whipple Consulting Engineers, Inc. (WCE). This topographic survey showed the existing roadways, existing structures, property lines, and existing ground surface elevation contours. This plan was prepared by WCE and was dated November 7,2013. The site was used as a golf course prior to our evaluation. The site is relatively level with some elevated golf greens and excavated areas for water hazards. The site is primarily grass-covered with scattered trees along the fairways and pine trees in the undeveloped area to the northwest. The clubhouse building is present at the southwest corner. In addition, we performed a preliminary geotechnical evaluation for the property in December 2013. The results of that evaluation, along with our opinions and recommendations, are summarized in our Preliminary Geotechnical Evaluation dated December 31,2013. P.O. Box 1566, Veradale, WA 99037 Phone 509-209-6262 J Addendum to Full-Scale Drywell Testing Painted Hills Golf Course Spokane Valley, WA Inland Pacific Engineering Company Project No. 16-249A 4403 South Dishman-Mica Road August 22, 2017 Page 2 We also perfonned a geotechnical evaluation for certification of the existing levee along Chester Creek in April 2014. The results of that evaluation are summarized in our Geotechnical Evaluation report dated February 12,2015. Lastly, we perfonned a geotechnical evaluation in July 2015 consisting often 50-foot borings in the south half of the property. The results of that evaluation are summarized in our Geotechnical Evaluation Phase 2 report dated July 23,2015. FIELD EVALUATION A geotechnical engineer from Inland Pacific Engineering Company (lPEC) perfonned a full-scale drywell test on the Type 2 drywell (double depth) on May 6, 2016. The drywell test was perfonned in accordance with the Spokane Regional Stonnwater Manual, Appendix 4B procedures. The drywell was installed at the location shown on Figure 3 (attached). ANALYSIS AND RECOMMENDATIONS We calculated a design outflow rate for the existing drywell to be 1.05 cfs for design. This recommended design outflow rate included a safety factor of 1.1 as required by the SRSM. Using this design outflow rate and assuming a typical infiltration area of 600 square feet for a Type 2 drywell, we recommend using a design infiltration rate of 1.8 x 10-3 cubic feet per second per square foot (cfsIW). This recommended infiltration rate also includes a safety factor of 1.1. REMARKS This report is for the exclusive use of the addressee and the copied parties to use in design of the proposed project and to prepare construction documents. In the absence of our written approval, we make no representations and assume no responsibility to other parties regarding this report. The data, analyses, and recommendations may not be appropriate for other structures or purposes. We recommend that parties contemplating other structures or purposes contact us. Services perfonned by the geotechnical engineers for this project have been conducted in a manner consistent with that level of care ordinarily exercised by members of the profession currently practicing in this area under similar budget and time restraints. No warranty, expressed or implied, is intended or made. l l • ..J Addendum to Full-Scale Drywell Testing Painted Hills Golf Course Spokane Valley, WA Inland Pacific Engineering Company GENERAL REMARKS Project No. 16-249A 4403 South Dishman-Mica Road August 22, 2017 Page 3 It has been a pleasure being of service to you for this project. If you have any questions or need additional information, please do not hesitate to call me at (509) 209-6262 at your convenience. Sincerely, Inland Pacific Engineering Company Paul T. Nelson, P.E. Principal Engineer l I J .. ~ August 22, 2017 Project No. 16-249 NAI Black c/o Mr. Bryan Walker 107 South Howard Suite 500 Spokane, W A 99201 Inland Pacific Engineering Company Geotechnical Engineering and Consulting Re: Mounding Analysis Painted Hills Golf Course Property 4403 South Dishman-Mica Road Spokane Valley, WA Dear Mr. Walker: As requested by Mr. Todd Whipple of Whipple Consulting Engineers, Inc. (WCE), we have prepared this report for the above-referenced site in Spokane Valley, Washington. The purpose of our services was to perform a mounding analysis for the proposed infiltration galleries at the north side of the site. This report summarizes the results of our additional engineering analyses and opinions. AVAILABLE INFORMATION We were provided a topographic survey for the project site by Whipple Consulting Engineers, Inc. (WCE). This topographic survey showed the existing roadways, existing structures, property lines, and existing ground surface elevation contours. This plan was prepared by WCE and was dated November 7,2013. The site was used as a golf course prior to our evaluation. The site is relatively level with some elevated golf greens and excavated areas for water hazards. The site is primarily grass-covered with scattered trees along the fairways and pine trees in the undeveloped area to the northwest. The clubhouse building is present at the southwest comer. We were also provided civil plans for the roadway improvements. The plans showed the layout and elevations of the proposed roadways and elevation contours. The plans were prepared by WeE and dated August 17, 2016. P.O. Box 1566. Veradale. WA 99037 Phone 509-209-6262 l J Mounding Analysis Painted Hills Golf Course Property Spokane Valley, WA Inland Pacific Engineering Company Project No. 16-249 4403 South Dishman-Mica Road August 22,2017 Page 2 In addition, we perfonned a preliminary geotechnical evaluation for the propelty in December 2013. The results of that evaluation, along with our opinions and recommendations, are summarized in our Preliminary Geotechnical Evaluation dated December 31 , 2013. We also perfonned a geotechnical evaluation for certification of the existing levee along Chester Creek in April 2014. The results of that evaluation are summarized in our Geotechnical Evaluation report dated Febmary 12,2015. Furthennore, we perfOlmed a supplemental geotechnical evaluation in July 2015 consisting often, 50-foot borings in the south half of the property. The results ofthat evaluation are summarized in our Geotechnical Evaluation Phase 2 report dated July 23, 2015. We also perfonned a second supplemental geotechnical evaluation at the north end of the property to evaluate soil conditions at depth and to better defme the static groundwater elevation in this area. We then perfonned a full-scale drywell test on a drywell installed near Boring B-1 from our second supplemental geotechnical evaluation. The results of these evaluations are summmized in our Supplemental Geotechnical Evaluation dated April 19, 2016 and our Full-Scale Drywell Testing report dated June 28, 2016. ANALYSIS AND OPINIONS We perfonned a mounding analysis for the proposed infiltration galleries to assess potential down- gradient impacts due to infiltration of the 100-year flood event. We performed the analyses based on work by Bianchi and Mucke1 (1970) and using methods developed by Todd (1080). Using these methods, we estimated the geometry of groundwater mounding by using the hydraulic conductivity (permeability) calculated based on our full-scale drywell test using the United States Bureau of Reclamation USBR 7300-89 procedure and transmissivity of the soils to estimate the mounding as a function of distance from the center of an equivalent square pond basin. We used a specific yield of 0.27 for the soils and an unsaturated aquifer thickness of 70 feet based on our previous borings. The annual stormwater volume and pond area were provided by WeE. The following table summarizes the input values. Water Volume Total Gallery Hydraulic Location Conductivity (ft3) Area (ft2) (cmls) Infiltration Gallery 72,384 33,928 7.1 x 10-3 For the flood event stormwater volume, we calculated a groundwater mound height ranging from 9.01 feet at the pond center dissipating to less than 6 inches approximately 275 feet from the center of the pond. Based on the results of the mounding analysis and the depth to groundwater, it is our l J ...J I -' Mounding Analysis Painted Hills Golf Course Property Spokane VaHey, WA Inland Pacific Engineering Company Project No. 16-249 4403 South Dishman-Mica Road August 22, 2017 Page 3 opinion that infiltration of stormwater in the proposed pond will not have significant down-gradient adverse impacts and will likely migrate north towards the Spokane River. Results of our mounding analysis are attached. REMARKS This report is for the exclusive use of the addressee and the copied parties to use in design of the proposed project and to prepare construction documents. In the absence of our written approval, we make no representations and assume no responsibility to other parties regarding this report. The data, analyses, and recommendations may not be appropriate for other structures or purposes. We recommend that parties contemplating other structures or purposes contact us. Services performed by the geotechnical engineers for this project have been conducted in a manner consistent with that level of care ordinarily exercised by members of the profession currently practicing in this area under similar budget and time restraints. No warranty, expressed or implied, is intended or made. GENERAL REMARKS It has been a pleasure being of service to you for this project. If you have any questions or need additional information, please do not hesitate to call me at (509) 209-6262 at your convenience. Sincerely, Inland Pacific Engineering Company Paul T. Nelson, P.E . L ~_ L l __ ' L IPEC Inland Pacific Engineering Company Goot.clullc.I Engineering and Consulting Parameter Area of Infiltration Length of Equivalent Square for Basin Inflow Rate (total) Inflow Rate (per unit surface area) Time Since Start of Inflow Distance From Center of Recharge Hydraulic Conductivity Aquifer Thickness Transmissivity Specific Yield Distance Ratio U(4TtlS)05 hSlWt Mound Height L L L '-J J L--1 __ 1 Project Number: 16-249 Test Location: Client: NAI Black 100-YEAR FLOOD GROUNDWATER MOUND HEIGHT CALCULATIONS -INFILTRATION GALLERY IProject: Painted Hills Symbol Units A, If 3.4E+04 L ft 184 WI ft3/day 72384 W ftldav 2.1 t days 3 x ft 0 k cm/s 7.1E-03 b ft 70 T ft2/dav 1409 Sy dimensionless 0.27 xlL dimensionless 0.00 w dimensionless 0.74 1II dimensionless 0.38 H ft 9.01 3.4E+04 3.4E+04 3.4E+04 3.4E+04 184 184 184 184 72384 72384 72384 72384 2.1 2.1 2.1 2.1 3 3 3 3 92 184 276 7.1 E-03 7.1E-03 7.1 E-03 7.1E-03 70 70 70 70 1409 1409 1409 1409 0.27 0.27 0.27 0.27 0.50 1.00 1.50 0.00 0.74 0.74 0.74 0.74 0.25 0.14 0.02 0.00 5.93 3.32 0.47 0.00 Inland Pacific Engill eenng Company P.O Box 1566 Veradale. WA 99037 Ik -0.0071 cm/s -I Distance 3.4E+04 3.4E+04 3.4E+04 184 184 184 72384 72384 72384 2.1 2.1 2.1 3 3 3 7.1 E-03 7.1E-03 7.1 E-03 70 70 70 1409 1409 1409 0.27 0.27 0.27 0.00 0.00 0.00 0.74 0.74 0.74 0.00 0.00 0.00 L- Infillration Gallery 3.4E+04 3.4E+04 3.4E+04 184 184 184 72384 72384 72384 2.1 2.1 2.1 3 3 3 7.1E-03 7.1E-03 7.1E-03 70 70 70 1409 1409 1409 0.27 0.27 0.27 0.00 0.00 0.00 0.74 0.74 0.74 0.00 0.00 0.00 "-"-"-"-"-"-"-"---- - -- ---------_/ I '~ ____ 2_~DA~N~ ___ : __ +_ l'< '2' SSS"52'00"E 90.00' "'.".,-::t-----....;..;;.;",;;,..;;.....,:L;;.::""'.J I'? C).ao' R20 <S? -iC\J . ~ ex. g . w E HOUSE j In ~ 2 co s 12,110 S.F. 30' to n co N ;U 0 0 Col 0 0 z 1 CD oW N 0 n 0 ~ 0 to , LINE BEARING DISTANCE R1 N62°57 36 W 43.00 0 Z R2 N77°1445 E 39.84 I . 30' ~ ~ ~ t) ~ ( / I I I I I I I I / I I I / / I I / / I / SSS'46'48"E 95.00' ----l ~/ I PROJ #: 1 B'21 17 DATE: OB/09/1B DRAWN: JAG APPROVED: JAG SCALE: 1 "= 1 00' / / I I I I / I u-i/ I ~I I I I / I I I I I I I / L-____ .J PROPOSED CONDITIONS VERCLER RD. & 23RD AVE. LiWCE SPO-VAL, WASHINGTON WHIPPLE CONSULTING ENGINEERS CIVIL AND TRANSPORTATION ENGINEERING 21 SOUTH PINES ROAD SPOKANE VALLEY, WASHINGTON 99206 PH: 509-893-2617 FAX: 5()9..926-0227 August 20, 2018 ~WCE Whipple Consulting Engineers, Inc. City of Spokane Valley 11707 E. Sprague Ave, Ste. 106 Spokane Valley, WA 99206 Attn: Henry M. Allen, PE, Development Engineer Re: PAINTED HILLS FLOODPLAIN REVIEW #2 City Project No.: SUB-2015-0001 Review Comment Responses for Submittal #2 Dear Mr. Allen: RE~EIVED AUG 2 0 201J G:lY OF SPOKANE V/iLLEY Since the submittal and city comments, the concept of Levee protection from flood has been rejected by the City of Spokane Valley. This plan set has changed dramatically to a CLOMR-F concept of protection, where the lower areas below the BFE are filled. Additionally, while the capture and disposal of floodwater remained the same, the ultimate disposal shifted from solely a gravel gallery disposal to an infiltration Pond Storage and gravel gallery disposal. As comments no longer apply or have been changed the response this letter tries to resolve any concerns. Enclosed are our responses to City of Spokane Valley comments provided January 4, 2017 with regards to the Painted Hills PRD Floodplain/CLOMR second submittal. Our response is shown in bold following your comment. Note: SVSS = Spokane Valley Street Standards, SRSM = Spokane Regional Stormwater Manual, ROW = Right of Way General 1. Prior to construction permit release, the following needs to be accomplished: a. Copy of CLOMR from FEMA b. Plan approval We acknowledge that the items listed in a. through b. need to be accomplished for construction permit release. 2. Prior to construction acceptance, the following needs to be accomplished: a. Copies of the Department of Ecology (DOE) drywell registrations for all new drywells (submitted with construction certification) b. Record drawings showing as-built condition c. Revisions to HEC-RAS model and reassessment of the free board if construction has altered the channels from that depicted in the model d. Letter from design engineers certifying project constructed according to approved plans and specifications e. Levee certifications (44 CFR 65.10 (e)) 218~@Wis Pines Rd. • Spol<a ne Valley, WA 99206 1l PO Box 1566 • Veradale, WA 99j3jge 1 ~hone 509-8 93-2617 • Fax 509-926-0227 • WhippleCE.com • lnfo@WhippleCE.com Civil, Structural, Traffic, Survey, Landscape Architecture and Entitlements f. Construction Certification Package We acknowledge that the items listed In a. through f. need to be accomplished for construction acceptance. Flood Control Development Narrative 3. General -please address the requirement for an overflow path for the 100-year storm mentioned in SRSM chapter 2.2.4, paragraph on Infiltration Facilities. We appreciate that the SRSM has this requirement, but as with all standards, requirements are written to cover the majority of situations. There are always exceptions that need to be looked at differently which this site falls into. Since our site is the regional low point designated as compensatory storage, with any possible overflow route blocked by prior development, a requirement for an overflow route is setting us up for failure. The facilities in this submittal are for the relocation of the compensatory storage of floodwaters. Stormwater overflow disposal will be addressed with submittal of plans for each specific subdivision. 4. Background a. Page 1 paragraph 1-change ... when no flood events occurred ... to ... when no significant flood events occurred ... Paragraph revised to include "significant.'' b. Page 2 -since 40th is an east-west oriented street should references to "east of 40th Avenue" be changed to "north (or south) of 40th Avenue"? The portion of 40th Ave adjacent to Storage Area 6 runs northwest to southeast so we have revised the reference to "northeast of'. c. Change references to "Spokane Rathdrum" aquifer to "Spokane Valley Rathdrum Prairie" aquifer. Aquifer references have been revised. 5. Main Flow Across Thorpe Road a. Proposed Design i. Box Culvert/Open Channel-the text refers to 2-10" culverts but our records say that they are 18". Please check pipe size. We have checked the culverts in the field and there are 3-15" CMP culverts. Text revised. 8/20/2018 Page 2 ii. Pipe Mainline-text mentions that along Madison are manholes with sumps but, per WSDOT details, these structures are called catch basins. Please revise. Manhole has been revised to WSDOT Type II catch basin. iii. Gravel Gallery System - 1. Paragraph 1-please include the design outflow rates of the drywells and the pipe crosses (may need to provide calcs). The outflow rate of 162.64 cfs has been documented with the new gallery design. These calculations are provided in the flood control narrative appendix. 2. Paragraph 2 -The design flow of 64 cfs was at Thorpe, please revise the design flow to what it is at the gravel gallery system. The design flow rate for storage area 1 has been revised to 118 cfs as documented in the flood control narrative. iv. Infiltration Rate - 1. Paragraph 1-why is this paragraph included in that TP-29 is at the south end of the site by Thorpe whereas the gravel galleries are at the north end? The paragraph has been deleted. 2. Paragraph 2 -please show how the 1.8 x 10-3 cfs/sf design flow rate was derived. See IPEC addendum report dated 8-22-17 6. Secondary Flow Across Madison Road a. Paragraph 1 i. Second sentence -mention that the flow from the most northerly culvert ends up going into culvert at 30+42. Sentence revised to state flows goes to the south. ii. Third sentence-check that the culvert stations listed match those in the table below paragraph 3. Stations revised to match table. 7. Attachments - B/20/2018 Page 3 a. Provide outflow rate calculations for the HOPE crosses. If the head required to achieve the outflow rate is significant then check this water surface elevation as a downstream condition in the channel and pipe hydraulic calcs. After consultation with the Geotech, the crosses have been eliminated and 12" perforated pipe will be installed the entire length of the gravel gallery. b. Open channel calcs -the Q may be a little bit more than 64 cfs when the flow from the two pipes at the upstream end of the channel are included. The open Channel has been revised since the last submittal. The revised open channel occurs between the box culvert and headwall of the two -48" concrete pipes. The design flow has been based upon the 103 cfs 100 yr flood assuming that the channel to the south has been breached just before Thorpe Road. The flow from the roadside swales are anticipated to occur prior to the 100 yr flood, as they have a different time of concentration. c. Pipe System calcs - i. Hydraflow is not on FEMA's list of approved software programs. We recommend that before submitting the study you check with FEMA to see if they will accept this software. So noted Hydroflow calculations are no longer included in the analysis. ii. Include the two-foot-high level spreader at the downstream end of the system. A 1-foot high spreader, has been called out per the design of the hydraulic engineer (West Consultants) d. Gravel gallery- i. Confirm source of the infiltration rate. See IPEC addendum report dated 8-22-17 ii. Check totals for the sidewall area and bottom area columns. The gravel gallery calculations have been revised with the change to the design. e. Bio-filtration swale design -the Manning's n of 0.2 is for shallow flow conditions. What depth does King County consider to be "shallow"? The depth calculated in the analysis is over 4 feet. Use a Manning's n applicable to a 4-foot flow depth. The manning's n-value has been revised per the Open Channel Hydraulics book by Ven te Chow, specifically Curves for A table on Page 182. Please see the appendix of the Flood Control narrative for a copy of the referenced material. 8/20/2018 Page 4 Biological Evaluation 8. Section 4.3, paragraph 1-can a vegetative cover be greater than 100% (top of page 9)? See Biology Soil and Water, Inc. letter dated June 8, 2017. 9. Section 5.3, paragraph 2 -confirm that the items mentioned (work in channel only when dry, BMP's, spill protocols, minimal peripheral impacts, construction fences) are adequately provided in the construction documents. Notes have been added to plans covering these items. 10. Section 5.4-confirm that the items mentioned (BM P's, FEMA specifications) are adequately provided in the construction documents. Notes have been added to plans covering these items. 11. Section 6.2, page 26 -because the levees at the small bridges need to be raised, more than 200' of levee needs to be raised. See Biology Soil and Water, Inc. letter dated June 8, 2017. 12. Section 6.7, paragraph 1, fill of the 1% flood is being infiltrated. See Biology Soil and Water, Inc. letter dated June 8, 2017. Operations and Maintenance Plan 13. General: a. This manual needs to be incorporated into the overall O&M Manual for the whole site. Noted. This manual will be incorporated into an overall O&M Manual at the time of its development. b. Include the levee O&M manual from the Geotech Levee Evaluation and Certification report as an appendix. As the City of Spokane Valley has formally rejected the Levee design, all levee design and documentation has been removed. 8/20/2018 Page 5 c. Per CFR 65.6(a)(12) mention that the City Manager or designee will be the community official responsible for assuring maintenance activities are accomplished. Responsible official statement has been added on page 1. 14. Page 1: a. Top- i. Spell out what a PRD is. Abbreviations section has been added on page 1. ii. State the party who is responsible for O&M until the HOA is formed. Responsible party section has been revised to add Black Reality as the responsible party until the HOA is formed. b. Middle, bullet list -add bullet stating HOA is responsible for: Providing annual report each October to Spokane Valley Public Works describing the general status of sinking fund account and also specific inspections, findings and maintenance performed. Bullet items have been added with regards to reporting. c. Last paragraph before next section (1.00) -Change to say: The parties mentioned above are primarily responsible for all operations and maintenance of ... Paragraph has been revised to refer to the parties mentioned above. 15. Section 2.00, Drainage Facilities (page 2), paragraph 1- a. Second line -remove "possibly" and "that has historically flowed into the property and" Paragraph has been revised per the comment. b. Provide FEMA panel number and effective date. FEMA panel number and effective date have been added. Mainline manhole callout has been revised to WSDOT catch basins. 16. 3.00 Maintenance Requirements and Schedules: 8/20/2018 Page 6 a. Right after this section heading include: All inspections and repairs are to be performed by or directly overseen by a qualified professional per this schedule and following major events. Maintenance tasks are to be performed soon after the need is identified and before facility is to perform unless otherwise agreed to by the City. Repairs or replacements are to be completed immediately upon their identification unless otherwise agreed to by the City. Only qualified individuals may enter confined spaces. The above paragraph has been added. b. First paragraph, last line -change "recommended" to "minimum required" Recommended has been revised to "minimum required." Box Culvert. A table has been added identifying location and agency having jurisdiction. c. Chester Creek and Levee - i. Reference the levee O&M manual from the Geotech Levee Evaluation and Certification and include in the appendix. Reference to the O&M manual has been added to this section and the manual added as Appendix B. ii. Paragraph 1 - 1. 3rd sentence-add to the end: ... of the creek and along the north side of Dishman-Mica to Wilbur Road. This sentence has been revised to include additional language. 2. 4th sentence, revise to say: ... maintained to ensure flood carrying capacity is maintained and flood flows are ... This sentence has been revised to include additional language. 3. Last sentence, revise to say: "Maintenance of the channel and levee and obtaining permits to perform the maintenance shall be ,, This sentence has been revised to include additional language. 8/20/2018 iii. Paragraph 2, Maintenance Items - 1. pt bullet -Geotech O&M says grass should be 3" high or taller. Include that grass should not be taller than 1211 (per the Biological Evaluation) Page 7 This sentence has been revised to include additional language. 2. 3rd bullet -at end include that only native grasses are to be on the levee. A sentence has been added to allow only native grasses. 3. 5th bullet -after this bullet add the following bullet: * Filling out the levee checklist and include it in the annual report to the City. This sentence has been added. d. Concrete Channel, first bullet-add to the end of the sentence: ... and repair or replace damaged portions. This sentence has been revised to include additional language. Pipe lengths updated to current plan under Storm Drain Mainline section. e. Manholes and Catch Basins i. ist sentence -revise to say ... mainline pipe system has catch basins at pipe junctions and ... Sentence has been revised to replace manholes with WSDOT Type II catch basins and reference to manholes deleted in heading and throughout section. Catch basin "lids" added to annual inspection. Cross Culverts. Reference to manholes revised to WSDOT Type II catch basins and TV inspections revised to three years. f. Bio-infiltration Swale Maintenance - i. Include mowing? The bio-infiltration swale is not to be mowed. ii. Include removal of accumulated sediments. A sentence has been added for removal of accumulated sediment. g. Drywells/Gravel Gallery Infiltration Field -include that every X years the pipe and crosses are inspected by camera for clogging and debris. 8/20/2018 Page 8 A sentence has been added for camera inspection every three years. Fencing. Signs have been added to the twice a year visual inspection. 17. 4.00 Sinking Fund Direction has been added to update the fund calculations per contracted costs and to update each time new contracts are obtained. a. Regular O&M costs - i. Confirm that the annual quantities represent "A comprehensive visual inspection of the complete flood control drainage facilities should be conducted twice a year." e.g. Drywell cleaning is 2x/year so annual quantity should be 24. A cost has been added to cover two comprehensive system inspections. This removes the inspection element from the maintenance tasks. Therefore, drywell cleaning annually is a quantity of 12. ii. Mowing-mention which facilities are to be mowed Mowing description has been revised to include levee embankments. iii. Debris removal -mention which facilities are to have removal Debris removal description has been revised to include those facilities anticipated to need debris removal. iv. Pipeline TV inspection -mention which facilities are to be TV'd Pipeline TV inspection has been revised to include the facilities to be TV'd. v. Manhole inspection -are these the Catch Basins on the trunkline along Madison? Catch basin has been added to the manhole inspection description. vi. Include - 1. Levee inspection and maintenance Levee inspection is included in comprehensive system inspection. Levee maintenance is included in the mowing line item. 2. Madison cross-culvert inspection and maintenance 8/20/2018 Page 9 Culverts has been added to debris removal and pipeline inspection descriptions. 3. Swale reseeding and noxious weed removal A line item has been added for swale reseeding and noxious weed removal. 4. Fencing, access roads, parking pads, signs inspection and maintenance A line item has been added for fencing, access roads, parking pads, signs inspection and maintenance. 5. Cost to prepare annual report A line item has been added for cost to prepare annual report. A line item has been added at 20% of total annual costs for contingencies to cover unexpected costs. b. Replacement Costs - i. in the first line the manholes are catch basins per WSDOT, Table has been revised adding line items to break out each type of manhole, catch basin, etc .. ii. include trunkline along Madison and trash racks Table has been revised adding line items to break out each pipe size including trunkline, culverts and infiltration field. A line item has been added for trash racks. A line item has been added for signs. Preliminary Geotechnical Evaluation, Phase 1 18. Analysis and Preliminary Recommendations -paragraph 2 says that soils good for gravel galleries are in the south part ofthe site. So, the soils in the north part of the site are not good for gravel galleries? No, the first paragraph states that the site soils are suitable for subsurface infiltration. The second paragraph points out that in the southern portion of site where the alluvial soils are deeper, it may be advantageous to use gravel galleries as opposed to drywells. Supplemental geotechnical work including borings and a drywell test at the north end of the site demonstrate that infiltration is feasible. It is important to consider all of the available reports, and geotechnical information. 8/20/2018 Page 10 Full-scale Drywell Testing 19. Figure 1-show where the test occurred. See IPEC revised report dated 8-21-17. Flood Control Plans General 20. Please include the following City project numbers on all plan sheets: a. SUB-2015-0001 (Subdivision) Number has been added to all sheets. b. EGR-2016-0066 (Engineered Grading Permit) Number has been added to all sheets. c. FDP-2016-0007 (Floodplain Development Permit) Number has been added to all sheets. 21. All ROW dedications and easements shall be recorded prior to the use of the frontage improvements and flood control elements. Dedications for flood control elements need to be recorded prior to LOMR submittal with their file numbers entered on the plans. We have received and reviewed (comments sent December 15, 2016) the following for flood control elements: a. an access easement and a drainage easement for the flood control bioswale and infiltration areas, b. a temporary drainage easement (initially called a temporary construction easement) for the storm drain pipe along Madison Road, and c. a drainage easement along Thorpe Road. As per our discussions, these easements and dedications will be completed following CLOMR review prior to LOMR submittal. Please provide draft legal descriptions and exhibits for the following for flood control elements: a. Border Easements along Dishman-Mica that involve a levee, As per our discussions, these easements and dedications will be submitted for review and completed following CLOMR review prior to LOMR submittal. 8/20/2018 Page 11 b. Slope easements along levee slopes not covered by a border easement, As per our discussions, these easements and dedications will be submitted for review and completed following CLOMR review prior to LOMR submittal. c. Access easements along levees that are outside the border easement. As per our discussions, these easements and dedications will be submitted for review and completed following CLOMR review prior to LOMR submittal. Please provide draft legal descriptions and exhibits for the following (non-flood control elements): a. ROW dedication at the NE corner of Thorpe and Dishman-Mica, As per our discussions, these easements and dedications will be submitted for review and completed following CLOMR review prior to LOMR submittal. b. ROW dedication at the NW corner of Thorpe and Madison, As per our discussions, these easements and dedications will be submitted for review and completed following CLOMR review prior to LOMR submittal. c. ROW dedication to the BCR's of Roads A through Don Madison, As per our discussions, these easements and dedications will be submitted for review and completed following CLOMR review prior to LOMR submittal. d. ROW dedication to the BCR's of Road E and the multi-family driveway approach on Dishman-Mica, As per our discussions, these easements and dedications will be submitted for review and completed following CLOMR review prior to LOMR submittal. e. Border Easements along Dishman-Mica that don't involve a levee, As a levee is no longer part of the flood control design the need for an additional easement is being assessed. As per our discussions, these easements and dedications will be submitted for review and completed following CLOMR review prior to LOMR submittal. f. Border Easements along Thorpe and Madison, 8/20/2018 Page 12 As a levee is no longer part of the flood control design the need for an additional easement is being assessed. As per our discussions, these easements and dedications will be submitted for review and completed following CLOMR review prior to LOMR submittal. g. Access easement for Dishman-Mica sidewalk that meanders into site. As per our discussions, these easements and dedications will be submitted for review and completed following CLOMR review prior to LOMR submittal. 22. Based on the street classification and project soil types, a pavement design shall be required for Dishman-Mica, Thorpe and Madison per SVSS Chapter 8. A pavement design has been provided in IPEC report dated June 26, 2017. See flood control narrative for referenced report. 23. Please submit a striping and signage plan for Dishman-Mica Road. Coordinate with the Traffic Impact Analysis for required left turn lanes and two-way left turn lanes. Show how the two-way left turn lane will taper at the Chester Creek crossing where the pavement section narrows. Signage and striping plans for Dishman-Mica Road, Thorpe Road, and Madison Road have been provided on sheets Cl0.0, Cl0.1, & C10.2 24. Please provide a Design Deviation Request for the following: a. Two driveway approaches for Dishman-Mica Road (SVSS 7.8.2.b) 25. For proposed utility adjustments and relocations, the applicant/engineer is required to contact each utility purveyor impacted by the required utility relocations and - a. Discuss with the purveyor the proposed work including relocations and adjustments as well as the costs for these activities, So Noted, with the revised plans coordination with the water and sewer purveyors will be completed. b. Obtain from the purveyor a written statement that they acknowledge and concur with or have alternatives for the needed work, and So noted, c. Forward a copy of the statement to Spokane Valley Development Engineering. Receipt of statements will be required prior to civil plan approval. 8/20/2018 Page 13 So Noted, d. Show the location of any relocated utilities. Relocated utilities are shown on the Water and Sewer plans. 26. Please submit a drainage report for the roadside swales. Include curb inlet and non- flooded roadway width calculations. A drainage report has been prepared for the roadway frontage. 27. Confirm there is maintenance access to all stormwater and levee facilities (SRSM 11.1.6) and provide approaches where accesses connect to a road. Maintenance access has been provided for storm and flood control facilities. 28. If flood flows varied from those modeled and they ended up exceeding system design, for instance at the infiltration/gravel gallery area, will there be any time for response between the exceedance occurring and properties being inundated? As Flood Events occur over a period of days and weeks there is time to manage the flood control facilities if need be. The proposed flood control facility is designed to handle the 100-year flood event, with additional design capacity as a part of the design safety factor. In addition, a surge protection at the open channel and headwall is included that will take the surge into the lowered park area. This additional storage would eventually be channeled back into the flood system via a catch basin and pipe to the west 48" pipe. For any Flood event beyond the 100-year event the proposed finish floor of the residences and the commercial buildings are graded above the BFE, so any flooding would be maintained in the streets, with minimal incursion into the structures. See Flood Control Narrative for specific design information. 29. Incorporate into the design the recommendations mentioned in: a. The Biological Evaluation in sections 5.3 (e.g. best management practices, construction fences around minimized work areas, restoration of impacts) and 6.5 (signs). As the Levees are no longer part of the flood control system it is proposed that the implementation of the biological evaluation and management plan be prepared after the completion and survey of the completed fill, otherwise an approved plan would have ta be modified once the fill is surveyed. 8/20/2018 Page 14 b. O&M Manual, Drainage Facilities section (signs). Signs are proposed to be placed upon fences. Sheet C0.0 30. In the 'Dev. Const. lnsp.' contact information section, please revise the phone number to 599-6306 and the contact name to Ken Van Dyk. In the 'Roadways' section, please change the phone number to 720-5008 and remove the contact name. Applies to Sheet C9.0 as well. Contacts have been revised on sheets C0.0 and C9.0. 31. Make sure all sheet titles match the titles in the Sheet Index. Sheet titles and/or sheet index have been revised to match. Sheet C0.1 (General Notes) 32. SV Note #6 -change should to shall. Note revised to read "shall." Sheet C0.2 (Dishman-Mica Road Sections) 33. For the Dishman-Mica Road Widening Calculations: a. Provide a column that depicts the existing super-elevated cross-slopes and adjust the proposed cross-slopes to match. The minimum proposed cross-slopes shall be 2%, The widening calculations have been revised and the cross slope has been matched. b. Check the Proposed Curb Elevations. The proposed curb elevations are based upon the varying cross slope and have been checked accordingly. 34. For Sections 1 -3, please: a. Label the street centerline, The centerline has been labeled. b. Revise the cross-slope of the pavement widening to match the existing super- elevated cross-slopes and provide the range of cross-slopes, The cross slopes have been revised to match the existing cross slope. 8/20/2018 Page 15 c. Verify the pavement section with a pavement design, See IPEC Geotechnical Evaluation dated June 26, 2017. d. Specify PG 70-28 for the HMA pavement. The HMA pavement type has been added. 35. For Section 1, please: a. Revise the planter strip width to 7' per SVSS 7 .5.10, The planter strip width has been revised. b, Extend the border easement to the toe of the slope or provide a separate slope easement, The border easement has been extended to encompass the toe of slope c. Reference SVSS Standard Plan R-103 for the 6' sidewalk. The Standard Plan has been referenced. 36. For Section 2, please: a. list the range of pavement widths, The range of pavement widths does not vary within the cross section. The pavement width does change at the bridge crossing and becomes 19' wide. b. Remove the 10' border easement. Border easement has been revised to 15' 37. For Section 3, please: a. Verify the need for the roadside swale, The roadside swale along Dishman Mica Road has been reduced in size, and will capture any project flow and receive plowed snow from the road surface. b. Extend the border easement to the toe of the levee slope or provide a separate slope easement, The border easement has been revised. c. List the range of pavement widths, 8/20/2018 Page 16 The range of pavement widths are shown. See previous response. d. Adjust the 34' and 64' dimension strings to end at the ROW, Dimension strings have been adjusted. e. For the 8' asphalt path: locate the construction line location and specify the pavement section and a cross-slope. If maintenance vehicles will utilize the asphalt path, verify the width and pavement section. The asphalt path width and cross section have been revised to a 10-foot path with 1-foot shoulders. An alignment has been added and will act as the construction line. Sheet C0.3 (Thorpe and Madison Road Sections) 38. For Section 4, please: a. Provide applicable stationing for this section, Stationing has been added to the section. b. Reference SVSS Standard Plans R-102 for the curb and gutter and R-103 for the sidewalk, The standard plans have been referenced. c. Verify the pavement section with a pavement design. See IPEC Geotechnical Evaluation dated June 26, 2017. 39. Provide a separate cross section of Thorpe Road that includes the concrete channel. For clarity and simplification, the cross section of Thorpe Road and the channel/box culvert has been provided on Sheet CS.1. A note has been added to this affect. 40. For Section 5, please: a. Provide applicable stationing for this section, Stationing has been added to the section. b. Provide a pavement and gravel section for the meandering path, note that this path will be used by a vactor truck to clean out drainage facilities, A pavement section has been provided. 8/20/2018 Page 17 c. Label the range of cross-slopes for the widening per the widening calculations, The slope has been revised to be 3.00% d. Adjust the border easement width to account for the meandering path, The boarder easement has been revised to the width of the proposed tract. e. Label the varying swale widths to account for the meandering path, The swale width is uniform, the cross section has been revised to reflect the uniform width with a note listing the range of widths from swale to path. f. Label the dimension from the ROW to the centerline of the 60" storm pipe, This dimension has been added to the 2-48" pipes. g. Verify the pavement section with a pavement design. See IPEC Geotechnical Evaluation dated June 26, 2017. 41. For Sections 4 and 5 and the roadside swales, include the following or provide a separate swale section: a. 3:1 maximum side slopes, The slope has been labeled on a typical section. b. 12" treatment soil zone, The treatment soil has been called out on a typical section. c. If the following treatment soils are installed, the City of Spokane Valley does not require soil testing per SRSM: "For swales and ponds, the top 12 inches of soil shall consist of a thoroughly blended mix of 50% compost with 50% native soils." So noted. A note has been added to the typical swale section. d. Note requiring swale bottoms and side slops shall be lined with sod/hydroseed, A note for hydro seeding has been added with a seeding note on Sheet C4.1. e. Typical bottom dimensions and depth, A typical cross section has been provided with the elements of items a through f. 8/20/2018 Page 18 f. Show a typical drywell or catch basin section with the 6" treatment depth and minimum depth from rim to flowline. A typical catch basin has been shown with call outs of 0.5' bottom to rim and 0.8' bottom to flowline. Sheet Cl.3 (Site Element Plan) 42. Coordinate the 'Madison Rd Easement Plan' section with Sheet C0.3 . The plan and section have been coordinated. 43. Plan view calls out 2-10" culverts under Thorpe but our records say that they are 1811 • Please check pipe size. We have checked and measured the culverts in the field and there are 3-15" CMP culverts. The text has been revised. Sheets C3.00 -C3.23 44. Reference intersection detail sheet at all applicable intersections. The intersection detail sheet was referenced with the centerline-centerline callout in the plan view. 45. Make sure all proposed and existing ROW and all easements are labelled. a. Where levee is outside the ROW and Border Easements provide access and slope easements. The ROW and easements have been labeled. Sheet C3.00 (Dishman-Mica Road P&P) 46. For the sidewalk that extends from Dishman-Mica Road to onsite: a. Provide the station and radius of the curve, A reference is made to see sheet C3.03. Sheet C3.03 has a plan and profile for the sidewalk. b. Provide a plan view that shows the entire alignment of the onsite sidewalk. Plan view has been added on sheet C3.03. 8/20/2018 c. Provide finish grade spot elevations that comply with ADA guidelines and include a cross-slope for drainage. Page 19 Profile has been added on sheet C3.03.Cross slope callouts have been added on sheet C3.03. d. Show and label the access easement for all portions of the sidewalk located onsite. Access easement has been added on sheet C3.03. 47. Please identify the existing hydrant near STA 22+40 and the power pole and telephone pedestal near STA 22+60. Determine if relocations are required. The existing fire hydrant has been called out. There is no relocation necessary. 48. For the new guardrail it will need to extend farther to the south than indicated on the plan due to the posted speed limit and slopes. The curb and gutter does not provide an adequate barrier in this situation. Verify the required length of the guardrail and the clear zone requirements with AASHTO Roadside Design Guide. New guardrail has been called out two feet behind the curb at the location of the existing guardrail. 49. For Construction Note #10, specify the start STA for the guardrail and reference new guardrail only. Stationing for new guardrail has been added. See construction note 9. 50. For Construction Note #11, specify the start and end stations of the pavement taper. The required taper length shall be calculated per L = ws, where 'w' is the widening width and 's' is the posted speed limit of 45 mph. The pavement taper south of the Dishman-Mica Rd box culvert and at the north end of the property has been calculated by L=WS and the start and end stations have been called out. The taper just north of the Dishman-Mica Rd box culvert has been widened per the meeting on 6/12/17. 51. The Traffic Impact Analysis mentions street lights along Dishman-Mica. Please show the light locations and specify that the lights will be installed with the plat. Specify necessary conduit sleeves to be installed with the frontage improvements. Street lights have been called out at public intersections. 52. In the profile, adjust the Top of Curb elevations to match the existing super-elevated cross-slopes and the revised Road Widening Calculations from Sheet C0.2. 8/20/2018 Page 20 The TBC has been revised to match the existing super-elevated cross-slopes. Sheet C3.01 (Dishman-Mica Road P&P) 53. For Construction Note #2, please reference Sheet C0.2. Sheet CO.Z has been referenced in construction note 2. 54. For Construction Note #3, please reference a 'spill' curb, similar to Sheet C3.00. Spill curb is now referenced in construction note 3. 55. For Construction Note #4, reference the appropriate plan sheet and detail for the asphalt path details. The City does not have specific standards for asphalt pathways. Sheet and detail are now referenced in construction note 4. 56. Since the 8' pathway will be driven on, provide adequate turning radii around the approaches. With the removal of the levee the path will no longer be driven upon. 57. Verify Construction Note #5 for this sheet. Note 5 has been revised to reference a different construction item. 58. For the pedestrian ramps at Road 'E', provide sidewalks on each side of the Road 'E' to down to the ramps or provide sidewalks from the top of the levees down to the pedestrian ramps. Short sections of adjacent sidewalk at the ramps will be acceptable. Sidewalks and ramps are now provided at Sundown Road (road E). 59. Road E -show how stormwater flowing down/along Road E is captured before it gets to Dishman-Mica and is disposed of. Plan has been revised to direct stormwater off Sundown Rd via under Type 2 curb inlets into roadside swales behind the sidewalk/curb. See sheet C3.03 for details. 60. For Construction Note #10 please verify the Standard Plan R-113 reference, as it is intended for adjacent sidewalks. Note has been revised to reference Std Plan R-111. 61. For Construction Note #12, please verify the sheet reference. 8/20/2018 Page 21 Note has been revised to reference sheet C4.2. 62. For Construction Note #15, specify the start and end stations of the pavement taper. The required taper length shall be calculated per L = ws, where 'w' is the widening width and 's' is the posted speed limit of 45 mph. Taper stations have been added. Per meeting at the City, the taper length has been shortened to provide full width widening at the driveway approach. 63. For the approach at STA 35+25, show the curb returns and provide pedestrian ramps. Provide sidewalks down to the ramps. This is outside the match line and shows on sheet C3.02 64. Provide Type Ill barricades per SVSS Standard Plans R-142 at each approach and Road 'E' until they are operational. Construction note 13 added to provide for barricades. 65. Please provide centerline stations for the driveway approaches at STA 28+ 75 and 35+25. Centerline stations have been added. 66. In the profile, adjust the Top of Curb elevations to match the existing super-elevated cross-slopes and the revised Road Widening Calculations from Sheet C0.2. The TBC elevations have been revised to match the super-elevated cross-slopes. Sheet C3.02 {Dishman-Mica Road P&P) 67. See all applicable review comments from Sheet C3.01 for this sheet. (53)For Construction Note #2, please reference Sheet C0.2. Sheet C0.2 has been referenced in construction note 2. (54)For Construction Note #3, please reference a 'spill' curb, similar to Sheet C3.00. Spill curb is now referenced in construction note 3. (55)For Construction Note #4, reference the appropriate plan sheet and detail for the asphalt path details. The City does not have specific standards for asphalt pathways. Sheet and detail are now referenced in construction note 4. 8/20/2018 Page 22 (56)Since the 8' pathway will be driven on, provide adequate turning radii around the approaches. With the removal of the levee the path will no longer be driven upon. (57)Verify Construction Note #5 for this sheet. Note 5 has been revised to reference a different construction item. {63)For the approach at STA 35+25, show the curb returns and provide pedestrian ramps. Provide sidewalks down to the ramps. The plan has been revised. (65)Please provide centerline stations for the driveway approaches at STA 28+75 and 35+25. Centerline stations have been added. (66)In the profile, adjust the Top of Curb elevations to match the existing super-elevated cross-slopes and the revised Road Widening Calculations from Sheet C0.2. The TBC has been revised to match the super-elevated cross-slopes. 68. Please remove the extraneous hextag #1 near STA 39+75. The Hex tag has been removed. 69. For levee and 8' path to be installed on church property from STA 35+82 to 39+80: a. Please provide evidence of granted permission from the church to build on their property. With the removal of the Levee from the flood control system the levee on the church property has also been removed b. Provide access, slope and construction easements. A slope and construction easement has been shown. See sheet C4.0. 70. For Construction Note #9, specify the start and end stations of the pavement taper. The required taper length shall be calculated per L = ws, where 'w' is the widening width and 's' is the posted speed limit of 45 mph. Stations have been added. 8/20/2018 Page 23 71. Any relocated utilities shall be located outside of the clear zone. Construction note 7 required relocations to be outside the clear zone. Additional utility items have had hextags added. 72. For Construction Note #10 please verify the Standard Plan R-113 reference, as it is intended for adjacent sidewalks. Note has been revised to reference Std Plan R-111. 73. Provide Type Ill barricade per SVSS Standard Plans R-142 at the approach until it is operational. Construction note 11 added to provide for barricades. Sheet C3.10 (Thorpe Road P&P) 74. In the Left Top of Curb Profile, show all text for the vertical curves. Profile adjusted to show all text. 75. In the profiles, the minimum 'k' value for sag vertical curves is 50 per SVSS Table 7.1. As requested in the 6/12/17 meeting the difference in elevation between a VC with K=S0 and a VC with a K=40 has been calculated. The difference is 0.59'. Due to the lack of room to lengthen the existing VC the grades had to be changed to calculate the VC with K=S0. 76. In the profiles, the minimum 'k' value for crest vertical curves is 30 per SVSS Table 7.1. The length of room provided in this area of Thorpe allowed for the VC to be lengthened and meet the K value of 30. 77. For Construction Note #2, please reference Detail 4 on Sheet C0.3. Reference revised to Detail 4 on sheet C0.3. 78. For Construction Note #6, reference the roadside swale section in the detail sheets, in addition to S-130. Reference has been revised to Detail A on sheet C0.3 and Std Plan S-130. 79. Label existing sidewalk to remain between STA's 15+00 and 17+00. Label with stations has been added. 8/20/2018 Page 24 80. Construction Note #7 at STA 11+53.78 should reference a driveway approach with a separated sidewalk. See Standard Plans R-110 through R-112. Construction note 19 added to reference Std Plan R-110. 81. Identify hextag #10 at each end of the existing sidewalk near STA 15+00 and 17+00. Hextag 10 added with stationing. 82. For the change in direction of the sidewalks near ST A's 13+90, 14+75, and 16+75, please limit the maximum angle of change to 30 degrees. The angle has been revised to 30 degrees. 83. For Construction Note #17, please locate the drywell near the low point. Maintain 5' of horizontal clearance from the nearest curb inlet. Verify that the drywell rim will be 0.2S'minimum below the adjacent flowline elevation. The Catch Basin has been moved to the lowest pond level. 84. Please provide stationing for all curb inlets. Limit maximum spacing of curb inlets to 100', or less depending on curb inlet calculations. Locate the curb inlets to maximize swale treatment. Curb inlet location table added to sheet C3.11 per note on this sheet. Spacing has been revised per 100 ft maximum and/or to maximize treatment. 85. Roadside swales are considered flat for volume calculations where the swale bottom slope is 1% or less. Address all roadside swales where the street grades exceed 1%. Check dams have been added where slope exceeds 1%. See sheet C0.3 for check dam detail. Sheet C3.11 (Thorpe Road P&P) 86. See all applicable review comments from Sheet C3.10 for this sheet. (77)For Construction Note #2, please reference Detail 4 on Sheet C0.3. Reference revised to Detail 4 on sheet C0.3. (78)For Construction Note #6, reference the roadside swale section in the detail sheets, in addition to S-130. 8/20/2018 Page 25 Reference has been revised to Detail A on sheet C0.3 and Std Plan S-130. 87. Please provide a Construction Note for the 6' wide sidewalk at the box culvert. Construction note 18 added for 6 ft sidewalk 88. Drainage easement to be labeled as permanent. Easement label has been revised. 89. How will large debris lodged in the middle of the concrete channel get removed (say, at station 9+00)? Will equipment need to get down into the channel? If so, how? Provide access road and easement (include file number) along full length of channel? With the revised design, large debris that fits through the box culvert would flow strait through the open channel and would be pushed against the angled trash racks of the headwall as flood waters rise the debris would float/rise up the trash rack, thus clearing the inlet of debris. Additionally, a maintenance road and gate are placed above the headwall. With a mini-excavator any piled debris can be removed safely. See sheet CS.1 for more detail. Per previous discussions, easements will be recorded and file numbers added after the CLOMR is received. 90. Please provide a curb inlet at low point STA 19+56.36 and near STA 22+75. Provide stationing for all curb inlets. Limit maximum spacing of curb inlets to 100', or less depending on curb inlet calculations. Locate the curb inlets to maximize swale treatment. Inlets have been added. Curb inlet location table added to sheet C3.11. Spacing has been revised per 100 ft maximum and/or to maximize treatment. 91. For Construction Note #14 and the existing drywell to be abandoned, please specify that decommissioning drywells shall comply with WAC 173-218-120 and WSDOT Specs 7- 05.3(2) Abandon Existing Manholes. The following is required: a. Remove any structure within three feet of the land surface, b. Backfill up to three feet below the land surface with material that is uncontaminated, chemically and biologically inert, and that drains equal to or more slowly than the native material surrounding the UIC well, and c. Fill the remaining three feet directly below the land surface with native soil or other structurally sound material common with current engineering practices. Construction note revised and decommissioning notes added to sheet C3.11. 92. For Construction Note #16, please provide Thorpe Road stationing and offsets for each catch basin for construction clarity. 8/20/2018 Page 26 Construction note directs to sheet C5.1 for location info. 93. In the Centerline/Sawcut Profile, please provide the missing grade break elevations for STA's 23+35.57 and 23+55.57. Grade break elevations have been added. Sheet C3.12 (Chester Creek Culvert Extension) 94. Please revise the sheet title and Section 'A' title to match the Sheet Index on Sheet C0.0. Titles have been revised to match. 95. Please label Thorpe Road. Thorpe Road has been labeled. 96. For Section 1, a. Verify the ROW/easement dimensions. Sheet C0.3 shows a ROW width of 55'. ROW width revised to show 55 feet. b. Reference Std. Plan R-102 for the curb and gutter, Reference added to Std. Plan R-102. c. Reference Std. Plan R-103 for the sidewalk, Reference added to Std. Plan R-103. d. Specify how the curb and gutter will be secured to the precast panels, Curb and gutter will be doweled to the precast culvert sections. e. Set the top of sidewalk flush with the top of curb and gutter, Top of sidewalk revised to be flush with top of curb. f. The 4" HMA is the minimum thickness, it will need to vary to get the cross-slope. Note revised for 4" min thickness and thickness varies to achieve cross slope. 8/20/2018 g. Specify a tack coat shall be applied to the precast panel decking prior to placing the asphalt paving, Page 27 Note added to tack coat prior to paving. h. Provide a guardrail at the north end of the box culvert extension. A guardrail has been called out on the north end of the box culvert extension. 97. For Section 2, a. Provide construction details for the precast panel and footings, i. How will precast panel be secured to the existing culvert? The panel has been revised to a precast box culvert and the details are provided on sheet CS.21. Shop drawings to be provided at time of construction. ii. Footings need to be at or below elevation of existing culvert footings. Note added to install new footing at or below existing footings. b. Why is the FG@CL lower than the top of the precast panel? Section revised to show FG above culvert deck. Sheet C3 .20 -C3.23 (Madison Ro ad P&P) 98. In public meetings, street lights were promised along Madison Road. Please show the light locations and specify that the lights will be installed with the plat. Specify necessary conduit sleeves to be installed with the frontage improvements. Street lights have been added at the future street intersections. See construction note 19. Sheet C3.20 (Madison Road P&P) 99. See all applicable review comments from Sheet C3.11 for this sheet. (78)For Construction Note #6, reference the roadside swale section in the detail sheets, in addition to S-130. Reference has been revised to Detail A on sheet C0.3 and Std Plan 5-130. 100. Please provide stationing for all curb inlets. Limit maximum spacing of curb inlets to 100', or less depending on curb inlet calculations. Locate the curb inlets to maximize swale treatment. 8/20/2018 Page 28 Curb inlet location table added to sheet C3.20. Spacing has been revised per 100 ft maximum and/or to maximize treatment. 101. Roadside swales are considered flat for volume calculations where the swale bottom slope is 1% or less. Address all roadside swales where the street grades exceed 1%. Check dams have been added where slope exceeds 1%. See sheet C0.3 for check dam detail. 102. For Construction Note #9, utilities shall not be located in sidewalks per SVSS 6.2.2 & 6.2.3. Construction note9 has been revised to have utilities relocated outside of sidewalk. Relocation to be coordinated with utility company. 103. Construction Note #14-channel access may need to be shown for the full length of the channel. With the design change, channel access has been relocated to another sheet 104. Construction Note #16 at STA 10+75 should reference a driveway approach with a separated sidewalk. See Standard Plans R-110 through R-112 . With the design change the driveway has been removed. Sheet C3.21 (Madison Road P&P) 105. See all applicable review comments from Sheet C3.20 for this sheet. (78)For Construction Note #6, reference the roadside swale section in the detail sheets, in addition to S-130. Reference has been revised to Detail A on sheet C0.3 and Std Plan S-130. (lO0}Please provide stationing for all curb inlets. Limit maximum spacing of curb inlets to 100', or less depending on curb inlet calculations. Locate the curb inlets to maximize swale treatment. Curb inlet location table added to sheet C3.20 per note on this sheet. Spacing has been revised per 100 ft maximum and/or to maximize treatment. (l0l)Roadside swales are considered flat for volume calculations where the swale bottom slope is 1% or less. Address all roadside swales where the street grades exceed 1%. 8/20/2018 Page 29 Not applicable on this section of Madison Rd as grades do not exceed 1%. (102)For Construction Note #9, utilities shall not be located in sidewalks per SVSS 6.2.2 & 6.2.3. Construction note9 has been revised to have utilities relocated outside of sidewalk. Relocation to be coordinated with utility company. Sheet C3.22 (Madison Road P&P) 106. See all applicable review comments from Sheet C3.21 for this sheet. (78)For Construction Note #6, reference the roadside swale section in the detail sheets, in addition to S-130. Reference has been revised to Detail A on sheet C0.3 and Std Plan S-130. (l00)Please provide stationing for all curb inlets. Limit maximum spacing of curb inlets to 100', or less depending on curb inlet calculations. Locate the curb inlets to maximize swale treatment. Curb inlet location table added to sheet C3.20 per note on this sheet. Spacing has been revised per 100 ft maximum and/or to maximize treatment. (101)Roadside swales are considered flat for volume calculations where the swale bottom slope is 1% or less. Address all roadside swales where the street grades exceed 1%. Not applicable on this section of Madison Rd. (102)For Construction Note #9, utilities shall not be located in sidewalks per SVSS 6.2.2 &6.2.3. Construction note9 has been revised to have utilities relocated outside of sidewalk. Relocation to be coordinated with utility company. Sheet C3.23 {Madison Road P&P) 107. See all applicable review comments from Sheet C3.22 for this sheet. (78)For Construction Note #6, reference the roadside swale section in the detail sheets, in addition to S-130. Reference has been revised to Detail A on sheet C0.3 and Std Plan S-130. 8/20/2018 Page 30 (l00)Please provide stationing for all curb inlets. Limit maximum spacing of curb inlets to 100', or less depending on curb inlet calculations. Locate the curb inlets to maximize swale treatment. Curb inlet location table added to sheet C3.20 per note on this sheet. Spacing has been revised per 100 ft maximum and/or to maximize treatment. (l0l)Roadside swales are considered flat for volume calculations where the swale bottom slope is 1% or less. Address all roadside swales where the street grades exceed 1%. Not applicable on this section of Madison Rd. {102)For Construction Note #9, utilities shall not be located in sidewalks per SVSS 6.2.2 & 6.2.3. Construction note9 has been revised to have utilities relocated outside of sidewalk. Relocation to be coordinated with utility company. 108. In public meetings, it was mentioned that the project sidewalk would extend and connect to the sidewalk by the school to the north. Please investigate. The sidewalk has been shown and called out to extend to the existing sidewalk to the north approximately 300'. The meandering path ends at the property line. A 5' walk has been called out per construction note 21. 109. For the pedestrian ramp at the southwest corner of Madison Road and Road 'C', please connect the ramp to the 10' asphalt path. Ramp has been revised to connect to path Sheet C3.24 (Madison Road Storm Pipe Crossings) 110. For Sections 'A' & 'C', provide a 0.10' min. drop through the catch basin per SRSM 8.5.2. A 0.1' drop has been added to the catch basins. 111. For Sections 'C' & 'D', the soil cover over the culvert appears to be less than 1'. SRSM 8.4.2 requires culverts with soil cover less than 2' to be ductile iron. Soil cover is measured from top of pipe to bottom of asphalt pavement. Increase the soil cover to 1' and provide pipe data supporting the shallow soil cover for a CMP material. The pipe has been revised to call out DI. 8/20/2018 Page 31 112. Please specify the type of CMP. A note specifying the CMP has been added. WSDOT STD. 9-05.1(2). 113. Provide trash racks at the inlets of all the cross-culverts since the outlet of the 60" pipe has a trash rack. Trash racks have been added. See sheet C3.24 for details. 114. Structures at the 60" RCP should be catch basins not manholes (per the narrative). Please show the sump. Manholes have been revised to catch basins with sumps. See construction note 3 on sheet CS.3. 115. Please revise the sheet title to match the Sheet Index on Sheet co.a. The sheet title has been coordinated with the sheet index. Sheet C3.30 (Intersection Details) 116. For all details, label existing and proposed ROW's. Existing and proposed ROWs have been labeled. 117. For the Curve Table, please specify that the data is taken at the back of curb. A note has been added to this affect. 118. For Detail 1: a. Provide a widened border easement per SVMC 20.20.090, The border easements have been revised b. Provide curve data and spot elevations for the south edge of pavement, A radius length and spot elevations have been added. c. Adjust the separated sidewalk location to the back of the ramp, The sidewalk has been revised to meet the back of the ramp. d. Label the gutter slope at the base of the ramp. The gutter slope has been labeled. 8/20/2018 Page 32 119. For Detail 2: a. Rename 'Dishman-Mica Road' to 'Madison Road', The road name has been revised. b. Provide a widened border easement per SVMC 20.20.090, The border easements have been revised c. Revise the BCR top of curb spot elevation on Thorpe Rd to match the profile, The BCR has been revised to match the road profile. d. Verify that the gutter slope at the base of the pedestrian ramp is 2% or less. The gutter slope has been labeled and a max of 2% slope in front of the pedestrian ramp has been called out. 120. For Details 3-6'. a. Revise the BCR top of curb spot elevations on Madison Rd to match the profile, The BCRs have been revised to match the profile. b. Verify that the gutter slopes at the base of the pedestrian ramps and the cross- slope along the crosswalk are 2% or less, The gutter slope has been labeled and a max of 2% slope in front of the pedestrian ramp has been called out. c. The longitudinal slope of Madison Rd at each intersection is less than 0.8%. Adjust the Madison Rd BCR top of curb spot elevations to create a 0.80% minimum longitudinal slope without a cross gutter or a 0.50% minimum longitudinal slope with a cross gutter (SVSS 7.5.4) or lower the BCR spot elevations on Roads 'A' -'D' so the intersections slope to the west. The elevations have been kept so that water flows around the intersections to the east and will enter the roadside swales for treatment. 121. For Detail 7: 8/20/2018 a. Verify that the gutter slope at the base of the pedestrian ramps and along the cross walk are 2% or less, Page 33 The gutter slope has been labeled and a max of 2% slope in front of the pedestrian ramp has been called out. b. Provide the future design of Road 'E', provide curb inlets on Road 'E' at the east BCR's. See sheet C3.03 for the plan and profile of Sundown Rd (Road E). Type 2 curb inlets have been called out on the east BCRs. For Items 122 to 146 the Levee has been removed from the flood control plan including the referenced sheets Sheet C4.0 -C4.2 (Proposed and Existing Levees) 122. To prevent unauthorized vehicular access, provide gates/bollards/etc. at the ends of the levees and where the levees cross approaches. 123. At points along all project levees call out BFE and max required freeboard (44 CFR 65.10 (b)(l) ). Sheet C4.0 (Proposed Levee P&P) 124. Show construction line along levee alignment. Include data to locate the construction line in space when it leaves the road alignment. 125. Call out easements. 126. Profile: a. Label profile. b. Profile should be along top of levee. 127. For Construction Note #1, reference the appropriate plan sheet and detail for the asphalt path details. The City does not have specific standards for asphalt pathways. 128. Approach at 28+80 -there is concern that pedestrians crossing the approach on the levee may not be seen by drivers pulling into the approach. Please look into providing pedestrian crossing of the approach near the road. 129. For portions of the levee that cross the driveways and Road 'E', specify a 2% maximum cross-slope for pedestrians and a thicker pavement section for traffic. Sheet C4.1 (Proposed Levee P&P) 130. See all applicable review comments from Sheet C4.0 for this sheet. (124) Show construction line along levee alignment. Include data to locate the construction line in space when it leaves the road alignment. 8/20/2018 Page 34 (125) Call out easements. (126) Profile: a. Label profile. b. Profile should be along top of levee. (127) For Construction Note #1, reference the appropriate plan sheet and detail for the asphalt path details. The City does not have specific standards for asphalt pathways 131. In Section 'A': a. show the finish grade being flush with the top of path and cross-slope, b. specify the depth of HMA and what standard it should be compacted to, c. Should the elevation per plan arrow point to the top of asphalt? 132. Levee Construction Notes: a. Note 1-recompact to what standard? b. Notes 2 and 5 -provide titles that match those of the documents being provided. 133. Seeding Note - a. % doesn't add up to 100%, please check. b. Confirm that this seed mix is approved by FEMA (see Biological Evaluation sections 5.4 & 6.2) Sheet C4.2 (Existing Levee P&Pl 134. See all applicable review comments from Sheet C4.0 for this sheet. (124) Show construction line along levee alignment. Include data to locate the construction line in space when it leaves the road alignment. (125) Call out easements. (126) Profile: a. Label profile. b. Profile should be along top of levee. (127) For Construction Note #1, reference the appropriate plan sheet and detail for the asphalt path details. The City does not have specific standards for asphalt pathways (128) Approach at 28+80 -there is concern that pedestrians crossing the approach on the levee may not be seen by drivers pulling into the approach. Please look into providing pedestrian crossing of the approach near the road. 135. Include a note requiring all non-compliant vegetation be removed per Biological Evaluation section 6.2. 8/20/2018 Page 35 136. Plan View: a. It is anticipated that the whole length of the existing levee will need to be used by vehicles for maintenance. With this: i. Confirm that the 5.5' wide asphalt pathway has adequate width, ii. Verify the turn radii and pavement section for its entire length, iii. At the south end provide a turn-around or continue the path up to the parking lot. b. Move the beginning of the levee alignment to be contiguous with the alignment of the new levee. Identify where 0+00 is located. c. Please revise section references of C4.5 to C4.4. d. Use BFE values per the effective flood insurance study, e. Per CFR 65.l0(b}(l) there needs to be an additional foot of freeboard at the bridges. Please confirm that this is provided, f. Incorporate Geotech recommendations from section 3.4 (Embankment Protection) of the Levee Evaluation and Certification report, revised August 29, 2016. 137. Profile: a. Label profile, b. Levee elevation from 5+00 to 5+80 seems too low. Please check. 138. Construction Note 7 -in note for required minimum freeboard check the stations. 139. Levee Construction Notes 2 and 5 -provide titles that match those of the documents being provided. 140. In Sections 1 and 2, a. Provide station limits, b. Locate the construction line location on the levee, c. Call out a cross slope, d. Specify a crushed gravel base beneath the asphalt path and compaction standard. e. 141. If any existing onsite bridges will experience vehicular traffic, please provide a bridge load rating. Sheet C4.3 {Proposed Levee Cross Sections) 142. General - s120;201s Page 36 a. Identify where O is located, b. Locate pathway on all sections. 143. Section SL-1-check stations and elevations. 144. Section SL-4 -check elevations. 145. Section SL-9-please revise road name to Road 'E'. Sheet C4.4 (Existing Levee Cross Sections) 146. General -Identify where O is located, Sheet CS.O (Storm System Overview) 147. Include titles for profiles. Titles have been added to the profiles. 148. For upper profile provide stations for all structures. Stationing has been added for structures. 149. Construction Notes: a. Provide all applicable details sheets for all notes. The brief construction notes have been removed since the sheet is intended as an overview of the flood system. Detailed construction notes are on the storm sheets following CS.O. b. Note 5-"manhole" should be "catch basin". Revise standard plan callout and specify depth of sump. Check spelling of "labelled". The construction notes have been removed but where this item shows up on other sheets, the notes have been revised to indicate WSDOT catch basins with 2 foot sumps. Sheet CS.1 Concrete Channel P&P 150. Plan View: a. Invert elevation of pipe from SD-CB #1 at the channel wall doesn't match the elevation in CS.2. Please verify the pipe slope from SD-CB#l to the concrete channel. IE's have been verified. 8/20/2018 b. Include the 100-year stormflow in the system calcs from the pipes originating from SD-CB #1 and SD-CB #2. Page 37 The peak for the flow through the catch basins will occur much sooner than the peak for the channel flow, therefore, the catch basin flows have not been included. c. Show the fence located north of the channel in cross section A. The fence has been added. 151. Construction Notes: a. Note I -include CS.21 Note revised to include CS.21. b. Note 4 -include S-121 Note revised to include C-121. 152. Profile - a. Include slope down to culvert inlet. See revised slope callout on sheet CS.1 b. Check stationing on axis. Stationing has been verified. 153. Please provide structural calculations and details for the fence, retaining walls and footings in Section 'A' (loads, dimensions, reinforcing, connections, etc.). See sheet C6.0 and C6.l for structural details for retaining walls and footings. See separate package for calculations. Sheet CS.2 (Box Culvert and Channel Details) 154. Box Culvert Detail: a. General -Provide design details for box culvert and wing wall (design loading, dimensions, elevations, thickness, reinforcing, connections, etc.) See note 2. The contractor will supply shop drawings and design calculations when they pick a supplier of the pre-cast structure. b. Plan View - i. Drainage easement is permanent not temporary, The note has been revised. 8/20/2018 Page 38 ii. For culvert alignment line provide a bearing and a station equation where this alignment crosses the Thorpe alignment, See sheet CS.1 for bearing and station equation. iii. Check stationing of wing walls. Stationing of wing walls are from the culvert alignment and not Thorpe Rd and have been verified. c. Section 1 - i. Label the ROW, The ROW has been labeled. ii. Reference Std. Plan R-102 for the curb and gutter, Standard plan R-102 has been referenced. iii. Reference Std. Plan R-103 for the sidewalk, Standard plan R-103 has been referenced. iv. Specify how the north curb and the south curb and gutter will be secured to the precast panels, The curb and gutter will be cast onto the deck with dowels epoxied into the deck. The curb will be cast into the box section per the detail on CS.10. v. Set the top of sidewalk flush with the top of curb and gutter, The top of sidewalk has been set flush with the top of curb and gutter. vi. Specify a tack coat shall be applied to the precast panel decking prior to placing the asphalt paving, A note specifying a tack coat shall be applied has been added. vii. Provide guardrails at both ends of the box culvert. A guardrail at the south end of the box culvert has been provided. On the north end of the culvert there is a 7.5' sidewalk and there will also be a 6' chain-link fence for channel access control. There is no room to place a guardrail with these limitations. 8/20/2018 Page 39 viii. Adjust the 12' dimension to start at the face of the 6" curb. The dimension has been revised to 14.5 feet to accommodate standard precast box sections .. ix. Verify the precast panel deck thickness with Section 2. The thickness has been revised so sections 1 and 2 match at 1.5 feet. x. The 4" HMA is the minimum thickness, it will need to vary to get the cross-slope. A note has been added specifying a varying thickness. xi. For slope down into the culvert inlet - 1. What is the stormwater velocity? Per the Capacity calculation of the box culvert, at a depth of 2 feet and an area of 56.66 sf the velocity of 216.4 ds (which is twice the 100-year storm rate) has a projected velocity of 3.82 ft per second. Per Open Channel Hydraulics, Chow section 7-9 The Maximum Permissible Velocity Figure 7-3 of the U.S.S.R. Data shows that a 200 mm or 8" particle or rock surface can withstand a velocity of 13 ft per second +/-before scour occurs. 2. Is erosion protection needed? Erosion protection has been added. 1' -2' angular rip-rap 3' deep has been called out. The erosion protection extends up the slope to the right-of-way. Based upon the information of item 1 with the erosion protection there is no scour anticipated. d. Section 2 -bottom of box is alluvial bed. Calculate scour and set footings below scour. The bottom of the box is rocked as well as the approach within the ROW. See response above. 155. Channel and Pipe Connection: a. General -Provide design details for channel and trash rack (loads, dimensions, reinforcing, connections, etc.) Structural details have been provided on sheet CG.0 and C6.1. Trash rack details have been provided on sheet CS.6. 8/20/2018 b. Plan View - i. There are two set of lines where the channel turns, remove lines that do not represent the channel geometry Page 40 The line has been removed and the channel has been hatched to more clearly show where the channel bottom is. ii. Provide channel alignment details and location of pipe inlet. The alignment location in the channel bottom is centered iii. Drainage easement is permanent not temporary, The drainage easement label has been revised. Sheet CS.3 (Madison Pipe P&P) 156. Construction Notes: a. Note 3 -Structures at the 60" RCP should be catch basins not manholes (per the narrative). Call out standard plan for catch basins and specify depth of sump. Note revised to catch basins with 2 ft sump. b. Note 5 -is the concrete outlet a pad or slab (see CS.4)? Construction note 4 on sheet CS.3 revised to pad. c. Note 7 -specify frame and grate type and include S-121 reference. Construction note 7 has been revised to include Type 1 Frame and Grate and to reference SVSS S-121. 157. Plan view: a. Make sure all structures are accessible for cleaning and have a construction note, Meandering path to be used for access. b. In 60" pipe why is there a structure at 22+45? The pipes and structures have been revised. 158. Profile: a. Provide stations for all structures on concrete pipe, Stationing has been provided for all structures. b. Make sure all pipes have length and slope information, 8/20/2018 Page 41 Pipe information has been verified for all pipes. c. Provide offset at 60" pipe outlet. A station and offset from Madison Rd has been provided. 159. For the culverts under Madison Road, Spokane County GIS shows that there may be a 24" pipe near station 23+50. Please check. All Madison Rd culverts have been surveyed and verified with no evidence of a 24" culvert. 160. Include the 100-year stormflow in the system calcs from the pipe originating from SD-CB #6. The 100-year flood has been added, please see the flood control narrative Sheet CS.4 (Bioswale P&P) 161. Include a short wall at the downstream end of the bioswale as a last trap for sediment. The design has been revised to include a 1' deep settling pond at the bottom of the bioswale, with a 20' wide rock weir overflow into a 2' deep infiltration pond with a field of drywells set at 1' above the pond surface. This is the design that prevents sediment from entering the gravel gallery. 162. Plan View: a. Clean up overlapping info, Labels have been revised. b. Provide dimensions/alignment/geometry information for fence, channel and pipes to locate them in space. Station and offset has been provided to Madison Rd to give reference of location in space. c. Confirm all structures can be accessed for maintenance. An access maintenance road has been provided. d. Provide all dimensions for hammerhead turn around. Dimensions have been provided. 8/20/2018 Page 42 e. Provide file number for easement. Space has been provided for inserting file number once easement is recorded after receipt of CLOMR-F comments prior to LOMR submittal per our discussions. 163. Construction Notes: a. Make sure all notes have pertinent detail sheets referenced. Verified. b. Note 3 -gate should be wider than road. Double swing gate width has been revised and is called out to be 16'. c. Note 9-specify frame and grate type and include 5-121. Construction note 9 has been revised to include Type 1 Frame and Grate and to reference SVSS S-121. d. Include note for infiltration head wall. The infiltration headwall h~s been removed from the design 164. Bioswale Inlet Cross Section: a. Provide design details (dimensions, elevations, thickness, reinforcing, connections, etc.). See sheet C6.0 and CG.l for structural details. b. Provide details for trash rack. See sheet CS.3 for trash rack details. c. In upper drawing check the orientation of the section arrows. Revised. d. Include the concrete level spreader in the hydraulic calcs. The level spreader has been added to the west consultants' calculations. 165. Typical Bioswale Section A a. Call out minimum depth of section. 8/20/2018 Page 43 The minimum7 foot depth of the section has been added. b. The O&M manual says the side slopes are 3:1, please correct. Manual has been revised to 2:1 side slopes. 166. Narrative says bioswale will be seeded not sodded, please revise. Note revised to seed the bio-swale. 167. Profile -show proposed grade. The proposed grade of 1.00% has been added. 168. Include the 100-year stormflow in the system calcs from the pipe originating from SD-CB #7. The peak for the flow through the catch basin will occur much sooner than the peak for the mainline flow, therefore, the catch basin flow has not been included. Sheet CS.5 (Infiltration P&P} 169. Plan View: a. Provide alignment information for pipes and structures to locate them in space. Station and offset of Madison Rd has been provided at corners to locate them in space. b. Confirm all structures - i. Have rim and inlet elevations and that elevations match those in profile. Rim and invert elevations have revised and verified. ii. Can be accessed for maintenance (especially by Vactor per the project narrative). Distance has been verified. c. Provide structure numbers to relate structures to those in the profile. Structure numbers have been provided in plan and profile views. d. Provide file number for easement. Space has been provided for inserting file number once easement is recorded after receipt of CLOMR-F comments prior to LOMR submittal per our discussions. 8/20/2018 Page 44 170. Profile: a. Provide stations at structures. Stationing has been provided for structures. b. Show proposed grade. The proposed grade matches existing grade. 171. Construction Notes: a. Make sure all notes have pertinent detail sheets and standard plans referenced. Verified. b. Note 7 -specify drywell type. The drywells are per City of Spokane Valley standards with additional barrels to achieve added depth. c. Note 8 -specify fabric class. The fabric class has been specified. d. Note 9 -provide standard plan. Note 9 has been revised. e. Include note for infiltration head wall. The infiltration headwall has been removed from the design. Sheet CS.6 Infiltration Headwall Details 172. Provide design details for headwall, channel and trash rack (loads, dimensions, elevations, thickness, reinforcing, connections, angles, etc.). 173. Call out spacing between pipes. 174. Provide stations at end of channel and at pipe inverts. The infiltration Headwall has been removed from the design. Sheet CS.7 (Infiltration Headwall Details) 175. Drain field cross section -provide complete spec reference. 8/20/2018 Page 45 176. 24" HDPE Cross Detail -specify filter fabric and how it is attached to pipe. The design has been revised. Sheet C9.0 (SWPPP Cover} 177. Legend -there isn't a storm drain pond, please revise. "Pond" revised to "facility" as we don't want washout at the bio-swale. 178. Provide protection at infiltration headwall. Protection at the infiltration headwall has been added. CLO MR Application The CLOMR Application has been revised since the City's rejection of the Levee Design. A CLOMR-F application has been provided. Narrative 179. Page 9 & page 14 paragraph 1-mentions that the infiltration facility maximum design flow is 84 cfs. Where was that flow rate obtained? 180. Page 13, end of 2nd paragraph -may want to also reference the Geotech investigation for the latest drywell design which is the document titled "Full-Scale Drywell Testing ... ". 181. Please include page numbers for all the narrative's pages. HEC-RAS model 182. Proposed Madison concrete pipe is initially 4 feet in diameter then goes to 5 feet in diameter but the second pipe in the model is 6 feet in diameter, please revise and update the text in the narrative. 183. At the outlet of the 5-foot pipe include the concrete level spreader (sheet CS.4). Forms 184. Riverine Structures Form -does the new culvert under Thorpe need to be included in one of the C. BRIDGE/CULVERT sections? 8/20/2018 Page 46 If you have any questions, please don't hesitate to contact our office at 893-2617. We are also available to meet with either CSVand/or SCE staff to discuss these responses further. Sincerely, WHIPPLE CONSULTING ENGINEERS, INC. Todd R. Whipple, P.E. Cc: Bryan Walker, NAI Black Marianne Barrentine, Spokane County Email copies: 8/20/2018 Ken Puhn, West Consultants Paul Nelson, IPEC Larry Dawes, Biology Soil & Water, Inc. Page 47 dWCE Whipple Consulting Engineers, Inc. September 21, 2018 WCE No. 2013-1166 City of Spokane Valley 1021 o·E. Sprague Ave Spokane Valley, WA 99206 Attn: Henry Allen Re: Painted Hills PRD -Flood Control Plans Response to Comments #3 Dear Henry: We have received your comment letter dated September 14, 2018 and offer the following response. For clarity your comments are listed below with our response in Bold. General 1. In several locations, your letter dated August 20, 2018 refers to the City of Spokane Valley as formally rejecting the concept of utilizing levees for flood protection. The City has not made any rejection of a levee-based proposal. No decisions of on the proposal or any alternative variation of the proposal have been made by the City. In prior conversations the City has pointed out that its willingness to provide approvals as a local project sponsor pursuant to 44 CFR 65.10 in uncertain and cannot be assumed in advance. The choice of whether to pursue an application based on certification of a levee system or the current fill- based proposal is entirely up to the project proponent. Yes, you are correct, no official rejection of the levee system was proctored by the City. It was our presumption during several meetings that the City believed a Fill option might be a better option, which we have embraced. We apologize for any assertions to the contrary. 2. The amount of net fill (328,289 cubic yards) is significant. The City does not have prescribed mitigation standards for this level of activity. Please provide additional information on your plans for coordinating delivery and management of this fill, including steps occurring prior to and during phases of construction. For example, what will be the source of the fill? What haul routes will be utilized? What do you see as the timing of the fill work? Are there other environmental impacts from importing such a significant amount of fill? Please give consideration to potential mitigation measures associated with construction/fill transportation system impacts. 21 South Pines Rd. • Spokane Valley, WA 99206 ·· ~ PO Box i 566 • Veradale, WA 99037 Phone 509-893-2617 • Fax 509-926-0227 • WhippleCE.com • lnfo@WhippleCE.com Civil, Structural, Traffic, Survey, Landscape Architecture and Entitlements City of Spokane Valley -Response to Comments Painted Hills PRD Flood Control Plans September 21, 2018 Page 2 of2 These are all good questions and will have to be determined. WCE will work with the City to determine the appropriate routes to be used, trucks per day limit, etc. At this time WCE has not worked with IPEC on a schedule as the contract has not been awarded yet. We would propose these issues be incorporated into the EIS responses. 3. Please provide a disc with copies of the electronic files of the calculations including the hydrology and hydraulic models and the stormwater calculations. A disc will be provided when Ken Puhn of West Consultants returns to his office. However, these should be considered DRAFT until FEMA approval is received and should be considered work in progress and propriety and not for distribution. Flood Control Plans 4. Sheets C4.0, C520, C5.30, and C5.31 -please provide additional contour label information to make it clear and easy to determine the existing and proposed topography, elevations, and slopes. The existing ground contours have not been shown on any these sheets for clarity of the finish ground surface. As for Sheet C4.0 more labels have been added; hopefully to more clearly depict the elevation differences between the two surfaces. 5. Sheet C4.0 -do the net fill quantities include the drain rock for the infiltration pond? The net fill quantities do not include the drain rock. The drain rock volume is estimated to be 15,800-cy. If you have any questions or comments regarding this letter please feel free to contact me at (509) 893-2617. Sin e~~ Justin Penner, EIT JPP Encl: CC: File ~ Stantec December 17, 2018 File: 2047071100 Attention: Henry Allen, P.E. Project Manager City of Spokane Valley 10210 E. Sprague Ave. Spokane Valley, WA 99206 Dear Mr. Allen, Stantec Consulllng Services Inc. 621 W. Mallon Avenue, Sui1e 309, Spokane, WA 99201 Reference: City of Spokane Valley -Painted Hills -CLOMR, Ordinance & Hydrology Initial Completeness Review Stantec has contracted with the City of Spokane Valley (City) to conduct an extensive review of the Conditional Letter of Map Revision (CLOMR) submittal for the Painted Hills development submitted to the City. The first task of the review is to conduct an initial completeness review of the submitted material to verify that all documents, models, data, etc. required for the CLOMR submittal review have been provided. This letter provides a summary of the initial completeness review. This letter will not provide any statement regarding the quality or adequacy of the submitted material. Following the initial completeness review, a detailed review will be conducted. In general, the submittal appears to be near complete; however, Stantec has not estimated the effort required to address identified deficient items. If any item is found to be missing during the detailed review that was not discovered during the initial completeness review, Stantec will notify the City of Spokane Valley at that time. Below our signature block, you will find Stantec's comments for the Initial Completeness of the CLOMR, Ordinance and Hydrology reviews with respect to FEMA requirements. For a more complete breakdown of the CLOMR review, please refer to the attached CLOMR Checklist. Regards, Stantec Consulting Services INC. Alan Gay Russ Connole Associate, Senior Engineer Senior Project Manager • I • I () Stantec December 17, 2018 Henry Allen, P.E. Page 2 of 8 Reference: City of Spokane Valley -Painted Hills -CLOMR Review Initial Completeness Review cc: Zak Whitten, PE, Water Resources Engineer Erman Caudill, PE, Civil Engineer Attachments: CLOMR Initial Completeness, Ordinance Initial Completeness, Hydrology Initial Completeness CLOMR Initial Completeness I. There were numerous documents provided. It was assumed that the document "CLOMR Applicaton for the Proposed Painted Hills Development" would be the narrative provided to FEMA for the CLOMR review, but it is unclear whether or not the other information will be part of the submittal. A lot of information is provided in the "Painted Hills Flood Control Development Narrative", but it is uncertain whether this document will be submitted to FEMA or not. It is recommended that a more clear and easy-to-follow narrative be submitted to FEMA. The review for FEMA will be conducted by personal unfamiliar with the project and therefore, the information should be presented in such a way that the project narrative, purpose and details can be easily followed and understood. a. If both documents are to be submitted, it is recommended that language referring to the submittal as a CLOMR-F be revised. From the initital completeness review, it appears the analysis that is provided in the package will revise the floodplain mapping for three detailed studies, including the removal of Unnamed Tributary to Chester Creek. Therefore, a CLOMR is required which will establish new flood hazard mapping. With the new floodplains estabaslished, a CLOMR-F may not be required since the the properties will not be within the new, effective Base Floodplain established in the CLOMR. 2. The MT-2 Forms and the "CLOMR Applicaton for the Proposed Painted Hills Development" indicate that no change to the hydrology was completed for this task. The CLOMR Applicatoin also does not have a detailed write-up of the hydrology. It is Stantec's understanding that the basis of the floodplains being removed from this location is a combination of till and new infiltration basins. Given the infiltration basins are part of the hydrologic analysis and used a hydrologic program HSPF, it is recommended that a detailed narrative be added discussing the changes to the original Flood Insurance Rate Map (FIRM). For example, initial completeness review inticates that Unnamed Tributary to Chester Creek is being removed from the Flood Hazard mapping. Is the removal based soley upon fill or has the additional of infiltration basins removed floodplain? As stated previously, the FEMA reviewer will not have previous knowledge of the project or the methodologies and procedures used for the analysis. ~ Stantec December 17, 2018 Henry Allen, P.E. Page 3 of 8 Reference: City of Spokane Valley -Painted Hills -CLOMR Review Initial Completeness Review 3. CLOMR's require the submittal contain example documentation of legal notice to be sent to all affected property owners within and outside of the the City's jurisdiction, explaining the impact of the proposed action on their property. No documentation was found. 4. CLOMR submittal guidance states that in locations where sediment transport affects hydrology, the effects of sediment transport should be considered in the hydrology and Section F of Form 3 should be submitted. Will sediment have an impact to the infiltration basins? Documentation should be provided in the narrative stating whether or not sediment will have an impact and if so, how it will be mitigated. 5. No shapefiles or CAD files were provided. Spatial files representing the following are required: a. New cross-sections and profile centerlines for the new hydraulic model and results; b. New floodplain boundaries; c. All of the data used in determining the revised floodplain boundaries, flood profiles and floodway boundaries. This includes the contours deleveloped from the 2003 LiDAR. 6. The CLOMR application states that the topography used was the 2003 LiDAR from the effective FIS. However, the person who is assigned to review the CLOMR will not have access to this information. It is recommended that not only do you provide all the LiDAR information including the spatial files, but also the survey report [if available) to illustrate the topography data satifies the FEMA guidelines and specs (Vertical Accuracy needs to be +/-98cm) 7. The CLOMR submittal requires a certified topography map. In order for this to be completed, a registered engineer or surveyor will need to certify the topographic work map they prepared using the 2003 LIDAR data with a PE stamp. Ordinance Initial Com leteness This portion of our review has been organized by applicable Spokane Valley Municipal Code (SVMC) ordinance chapter. 1. Flood Plain Ordinance SVMC 21 .30 a. Plans. Screening Comment: Plans drawn to scale showing the general nature, location, dimensions, and elevations of the area in question have been provided. II ~ Stantec December 17, 2018 Henry Allen, P.E. Page 4 of8 Reference: City of Spokane Valley -Painted Hills -CLOMR Review Initial Completeness Review b. Application made for all relevant federal. state, and local permits. Screening Comments: i. A draft application has been prepared for a Conditional Letter of Map Revision (CLOMR) for FEMA. Pending detailed review, it appears to be unnecessary to submit a CLOMR-F (CLOMR-Fill) application. Please see the completeness review specific to the CLOMR. The letter from Todd Whipple addressed to Henry Allen dated August 20, 2018, states that a CLOMR-F is being sought, but the submittal package includes only a CLOMR application. ii. Plan title blocks imply that permits issued by the City of Spokane Valley will also be sought, and presumably permits will also be sought from Spokane County for portions of the project under Spokane County jurisdiction. However, a review of the submitted material does not include a draft or final version of a permit application to either entity. It appears that applications for the following local permits are missing: 1. Spokane Valley: Grading permit for placement of more than 50 cubic yards of fill. 2. Spokane County: Grading Permit for placement of more than 50 cubic yards of fill prior to issuance of a building permit. iii. The erosion and sediment control plan inclusion in the plan set indicates that the project proponents intend to comply with the requirement under the Washington Statewide Construction Stormwater General Permit to apply for coverage as a site disturbing more than one acre. This application process is generally done on-line within 60-90 days before construction is scheduled to begin, so application is premature at this time. We recommend written assurance that this is the project proponent's intent. iv. Drywell registration documentation to the Washington Department of Ecology will be needed since part of the flood control strategy includes drywell installation. A table included in the project documentation would provide assurance of intent to comply with this requirement. c. Watercourse maintenance, Screening comment A watercourse operations and maintenance plan has been noted as "awaiting completion per jurisdiction comments" (p259, CLOMR application). d. Public utility plans for water and sewer are included in the project package. () Stantec December 17, 2018 Henry Allen, P.E. Page 5 of 8 Reference: City of Spokane Valley -Painted Hills -CLOMR Review Initial Completeness Review e. Department of Ecology approval will be required for development in a floodplain. f. Demonstration that the project will not interfere with infiltration capacity is inherent in the design intent. g. Note that per SVMC 21 30.090, in the event the base flood elevation is increased by any amount. affected adjacent property owners must be notified, and provide their notarized approval. The detailed review will check if this provision applies; if it does apply, the applicants will be responsible for addressing this provision and they may be required to demonstrate compliance prior to any City approvals. 2. Critical Areas Ordinance SVMC 21 .40 a. A critical area report is required. The document in the CLOMR application package includes a report titled, "Painted Hills PRD, Biological Evaluation, Buffer Averaging, and Habitat Management Plan" that has many elements of a critical area report. However, it does not conform with the requirements of a critical area report included in SVMC 21 .40. Specifically, a statement in the document that it was prepared to conform to SVMC 21.40 appears to be missing. b . As impacts to the critical areas within the project limits are part of the project action, mitigation measures will be required. The report titled, "Painted Hills PRD, Biological Evaluation, Buffer Averaging, and Habitat Management Plan" includes many components of a mitigation plan. Its contents need to reflect the requirements for a mitigation plan included in SVMC 21 .40. Specifically, a cost estimate appears to be missing. The Erosion and Sediment Control Plan (ESCP) and what appears to be the critical areas mitigation pion are consistent. c. A monitoring plan is required as part of the ordinance. It appears that a mitigation monitoring plan is included in the report 1itled, "Painted Hills PRD, Biological Evaluation, Buffer Averaging, and Habitat Management Plan" includes many components of a monitoring plan. The monitoring plan must comply with SVMC 21.40. d. Sureties. A surety is to be supplied. Typically, a surety is negotiated once the critical area report, maintenance pion, and monitoring plan hove been accepted. e. Special Flood Hazard Area additional requirements must be included in the submittal package in accordance with SVMC 21 .40. Many of these requirements apply to content in the CLOMR application package. However, an index directing the reviewer and future users of the documents would make the package easier to use. 'I ' ~ Stantec December 17, 2018 Henry Allen, P.E. Page 6 of 8 Reference: City of Spokane Valley -Painted HIiis -CLOMR Review Initial Completeness Review 3. Land Disturbing Activities SVMC 24.50 a. A grading permit is required under this ordinance, consistent with the requirement under Flood Plain Ordinance SVMC 21.30. Components of the grading permit application include: i. A completed permit application form; this is not included in the documents reviewed to date. ii. Two sets of plans, and two copies each of reports, specifications, and reporting documents. However, noting that the reviewed materials are all on electronic media, the requirement for a second set of documents is mitigated. iii. Erosion and Sediment Control Plans area included, as are geotechnical reports, a drainage report, and a SEPA checklist. The outline above is not intended to be a comprehensive review of the submitted documents with respect to the referenced ordinances. This review letter is intended to alert the project proponents to missing documents. Once all missing documents are supplied, a comprehensive and complete review can commence. Hydrology Initial Completeness From a Hydrology standpoint, the fundamental question formulated based on a first pass review is this: A large pervious area currently allows infiltration in a distributed fashion into an underlying sand and gravel layer. The proposed development concentrates that flow and increases the volume by converting pervious to impervious, while allowing infiltration only at distinct locations. A series of dry wells and gravel galleries are incorporated into the development to try to promote similar overall infiltration characteristics as the previously more pervious tract. The test pits and borings indicate a cover soil with silt, clay, etc. that might slow down surface infiltration. However, there seems to be a continuous and more pervious sand and gravel layer below that can accept anything that infiltrates through that top layer (assuming it doesn't have a limited capacity). The geotechnical report alludes to the underlying groundwater being much deeper, but a full geologic section isn't provided. The proposed condition will likely have the same silt to clay type surface cover with the sand and gravel underlayment at a modest depth. In the absence of a more thorough regional hydrogeologic report, all of this leads me to conclude the infiltration approach can function, but the entire system is based on the assumed surface infiltration rates, the infiltration measures penetrating sufficiently through the surface to the underlying sand and gravel, and the assumption that the underlying more permeable layer is not confined and has excess capacity. I'm assuming the last point has been proven moot in this area, so the following questions are presented to get a better understanding of the importance of that infiltration rate . I () Stantec December 17, 2018 Henry Allen, P.E. Page 7 of 8 Reference: City of Spokane Valley -Painted HIiis -CLOMR Review Initial Completeness Review and how it relates to the design assumptions and so we can compare those assumptions to the previous work prepared for the effective FEMA study: 1. To help facilitate the review and to assure we aren't misinterpreting the design intent, please provide an annotated copy or copies of drawing sheet C 1 .0 and C 1.3 with indications of flow directions, peak discharges, estimates of total runoff volumes, and infiltration rates & volumes for a 100-year, 24-hour duration standard storm event based on FEMA Effective Data, Corrected Existing, and Proposed Conditions. Reference points should be placed at flow path splits, structures, significant infiltration points, and hydraulically significant points within the study area. Providing the discharge and volume values in an accompanying table with corresponding point numbers is acceptable. a. The purpose for the request is to help us perform a basic mass-balance and infiltration rate type review of the stormwater runoff with and without development. 2. An XP-SWMM model is provided for culverts under Madison Road. We request that this model be exported to EPA-SWMM format. The discharge values within the SWMM model will help with the hydraulic review. 3. Several proposed storm water facilities on the site are designed with dry wells and gravel galleries to promote infiltration. The geotechnical data indicates these features may be effective if properly designed, installed, and maintained. For FEMA CLOMR purposes they seem to be assumed to fully function as designed and infiltration is not affected by antecedent conditions. For City review and long-term maintenance considerations, what happens if these facilities fail and sufficient infiltration no longer occurs? This could be due to excessively wet antecedent conditions, accumulation of sediment and debris, bioaccumulation and clogging, or other causes. Are any structures at risk? Do any of the proposed or existing roadways overtop? Any downstream impacts due to additional discharge leaving the site? a. If this information is contained in the provided data, it was not readily apparent from the initial review; in the response cover letter for the revised submittal, please highlight where this information is located within the submittal 4. It appears the proposed infiltration pond at the northern boundary of the site has been sized to contain a 50-year storm based on simplified runoff assumptions using the rational method. Fundamentally, what happens during a 100-year, 24-hour storm event with a higher peak discharge and runoff volume? Have discharge hydrographs been developed and routed? Are the conveyance structures adequate to control that overflow? Similarly, if the basin does not provide sufficient infiltration, what structures are at risk? ~ Stantec December 17, 2018 Henry Allen, P.E. Page 8 of8 Reference: City of Spokane Valley -Painted HIiis -CLOMR Review lnlHal Completeness Review C a. The same question would apply for the modifications to Storage Area #6. The questions above are pertinent to the initial completeness review and our overall understanding. During the detailed review phase of the project, we're planning to review the HSPF model in greater detail and will document that review. Initial Completeness Summary The applicant shall address all initial completeness questions and comments listed in the CLOMR, Ordinance and Hydrology Sections above and submit an updated floodplain permit application that includes all elements to the City of Spokane Valley for review. ' ,, SOTVOf]~ l)O.lM1.11e ---a --:FValley · December 19, 2018 Mr. Todd Whipple Whipple Consulting Engineers 21 South Pines Road Spokane Valley, WA 99206 Community and Public Works l0210 E Sprague A venue • Spokane Valley WA 99206 Phone: (509) 720-5305 • Fax: (509) 720-5075 • www.spokanevalley.org Email: planning@spokanevalley.org RE: Painted Hills Planned Residential Development (PRD) File Nos: PRD-2015-0001, SUB-2015-0001, EGR- 2016-0066 and FPD-2016-0007: Floodplain Modification Supplemental Completeness Review Mr. Whipple: Due to the complexity of the flood control aspect of the project, the City has hired technical experts to assist the City with its review of the proposed floodplain modifications. The City's intention to retain subject matter experts for this aspect of the project was mentioned in the City's letter to you dated September 14, 2018. Stantec Consulting Services, Inc. (Stantec) was selected to perform the work. Stantec has reviewed your August 20, 2018, submittal to determine any additional information necessary to allow a detailed technical/substantive review. The additional required information is stated in the attached letter from Stantec. Once the requested information has been received by the City, the City will have Stantec conduct a detailed review of the proposed floodplain modifications to support the City's analysis of the applications identified above. This is expected to proceed in conjunction with the floodplain analysis and mitigation measures identified in the Draft Environmental Impact Statement that you and your consultants are currently working on. The City has not yet been provided any DEIS-related materials. We understand that Spokane County is reviewing that portion of the floodplain located outside of the City. However, please note that the City has determined that as part of its review of the floodplain, it will also review the portion located outside of the City since it is part of the same system and has the potential to impact the properties located within the City. The City will be contacting Spokane County to discuss coordination to avoid duplicative review where possible. Please address the items noted in the Stantec letter, as it is necessary for floodplain review and will be especially relevant and necessary once you provide the Draft Environmental Impact Statement. At this time no further action will be taken until this additional information is provided. If you have questions, I can be reached at (509) 720-5335. Respectfully, ,J;j~~ Lori Barlow, AICP Senior Planner LBarlow@spokanevalley.org Attachment: Stantec Consulting Services Inc. December 17, 2018 letter CLOMR Submittal Initial Screening Checklist Cc: David Black, Black Realty Inc., 107 S. Howard Street, Spokane, WA 99201 Bryan Walker, Black Realty Inc., 107 S. Howard Street, Spokane, WA 99201 Spokane Valley Deputy City Manager -John Hohman Spokane Valley Legal Department -Erik Lamb Spokane Valley Community and Public Works Dept.-Deanna Horton, Henry Allen March 8, 2019 dWCE WCE No. 2013-1166 Whipple Consulting Engineers, Inc. City of Spokane Valley 1021 0 E. Sprague Ave Spokane Valley, WA 99206 Attn: Henry Allen Re: Painted Hills PRD -CLOMR Review Stantec Comments Dear Henry: We have received the comment letter from Stantec Dated December 17, 2018 and offer the following response. For clarity the comment is shown below with our response in bold . . CLOMR Initial Completeness l. There were numerous documents provided. It was assumed that the document ''CLOMR Application for the Proposed Painted Hills Development" would be the narrative provided to FEMA for the CLO MR review, but it is unclear whether or not the other information will be part of the submittal. A lot of information is provided in the "Painted Hills Flood Control Development Narrative", but it is unce1tain whether this document will be submitted to FEMA or not. It is recommended that a more clear and easy-to- follow narrative be submitted to FEMA. The review for FEMA will be conducted by personal unfamiliar with the project and therefore, the information should be presented in such a way that the project narrative, purpose and details can be easily followed and understood. The WCE Flood Control Narrative has been revised, and included with this submittal. a. If both documents are to be submitted, it is recommended that language refening to the submittal as a CLOMR-F be revised. From the initial completeness review, it appears the analysis that is provided in the package will revise the floodplain mapping for three detailed studies, including the removal of Unnamed Tributary to Chester Creek. Therefore, a CLOMR is required which will establish new flood hazard mapping. With the new floodplains established, a CLOMR-F may not be required since the properties will not be within the new, effective Base Floodplain established in the CLO MR. The application being provided to FEMA is a CLOMR. The WEST authored report titled: CLO MR Application fol' the Proposed Painted Hills Development is the primary explanatory report associated with the CLOMR. The MT-2 Forms included in the report also report the application as a CLOMR. Some WCE materials which are provided as CLOMR report appendices inadvertently referred to a CLOMR-F rather than a CLOMR. Rather than revising all of the supplemental WCE materials, they will pro\ide a letter to the communities clarif}ing that references to a CLOMR-F should be considered as just a CLOMR. Since the primary CLOMR report and the MT-2 forms correctly reference a CLOMR, we believe this will be appropriately clear for the FEMA re,,iewer 21 South Pines Rd. • Spokane Valley, WA 99206 l PO Box 1566 • Veradale, WA 99037 Phone 509-893-2617 • Fax 509-926-0227 • WhippleCE.com • lnfo@WhippleCE.com Civil, Structural, Traffic, Survey, Landscape Architecture and Entitlements City of Spokane Valley Painted Hills PRD -Response Letter Stantec Comments March 8, 2019 Page 2 ofll 2. The MT-2 Forms and the "CLOMR Application for the Proposed Painted Hills Development" indicate that no change to the hydrology was completed for this task. The CLOMR Application also does not have a detailed write-up of the hydrology. It is Stantec's understanding that the basis of the floodplains being removed from this location is a combination of fill and new infiltration basins. Given the infiltration basins are part of the hydrologic analysis and used a hydrologic program HSPF, it is recommended that a detailed narrative be added discussing the changes to the original Flood Insurance Rate Map (FIRM). For example, initial completeness review indicates that Unnamed Tributary to Chester Creek is being removed from the Flood Hazard mapping. Is the removal based solely upon fill or has the additional of infiltration basins removed floodplain? As stated previously, the FEMA reviewer will not have previous knowledge of the project or the methodologies and procedures used for the analysis. It should be noted that the FIS HSPF model was not modified for this CLOMR. The CLOMR report has been updated to better clarify this fact. The main WCE facility is designed to have a peak design outflow discharge that exceeds the 0.2% annual chance FIS inflows. Since the facility capacity exceeds the inflows, there is no remaining ponded water in the project site under the proposed design. Accordingly, no modifications were needed for the hydrologic model. The lower portion of the Unnamed Tributary is being removed from the floodplain based on the proposed infiltration facility in Storage Area 6. This is described on Page 11 of the CLO MR report. The facility (storage and infiltration) can contain the 0.2% annual chance flood. The left over bank flowpath for the Unnamed Tributary is based on failure of the levee on the left overbank between Highway 27 and the storage area. Since that portion of the channel will be conveyed via a culvert in the proposed design, there is no need for a without levee scenario. Accordingly, the removal of the left bank overflow path and the main flowpath of the Unnamed Tributary are based on a combination of a proposed culvert and the proposed infiltration facility in SA6. Additional text describing this has been added to the CLOMR report. 3. CLOMR's require the submittal contain example documentation oflegal notice to be sent to all affected property owners within and outside of the City's jurisdiction explaining· the impact of the proposed action on their property. No documentation was found. Property owner notifications are required prior to submittal to FEMA and the process for this has been discussed previously with the City and County during prior submittal and reviews of the CLOMR application. This project has been going on for some time and has undergone several changes during back and forth review and discussions between WCE and the City and County. Since the design has been evolving based on these discussions, in order to avoid public confusion, we are waiting until the City and County review is complete and we have agreement upon the proposed plan. At that point the final notification text will be provided to the communities who will place the text on letterhead and mail to the appropriate property owners. The notifications will be mailed either prior to or coincident with submittal to FEMA 4. CLOMR submittal guidance states that in locations where sediment transport affects hydrology, the effects of sediment transport should be considered in the hydrology and Section F of Form 3 should be submitted. Will sediment have an impact to the infiltration basins? Documentation should be provided in the narrative stating whether or not sediment will have an impact and if so, how it will be mitigated. City of Spokane Valley Painted Hills PRD -Response Letter Stantec Comments March 8, 2019 Page3 ofll The inflows to the Thorpe Box Culvert and the main infiltration facility flow through grassy fields, with no physical channel, at low velocities (average 1.5 ft/s). Due to the low velocities, combined with the natural filtering effects of the vegetation, it is not expected that sediment will have significant impacts to the infiltration facilities. Additionally, the proposed design by WCE also includes sumps within Manholes, a bioftltration swale, a settling pond and overflow weirs into drywells to allow for settlement of sediment prior to entering the gravel galley under the inf'lltration pond. The inflow to the Storage Area 6 infiltration facility flows through a grassy channel, at low velocity (average ~3 ft/s). It is similarly expected that the low velocities and filtering effects of the vegetation will minimize sediment transport into the facility. A similar design with sumps in manholes and overflow weirs into the drywells allows for settlement of sediment prior to entering the drywells of the triangle pond. Finally, WCE has developed a grading plan of the site that keeps the finish floor of all proposed structures 1 foot above the Base Flood Elevation (BFE). And WCE has developed an Operations and Maintenance Plan for the facility to ensure the facilities receive regular maintenance and inspections to minimized the long-term effects of sediment that may enter these infiltration systems. 5. No shapefiles or CAD files were provided. Spatial files representing the following are required: a. New cross-sections and profile centerlines for the new hydraulic model and results; b. New floodplain boundaries; c. All of the data used in determining the revised floodplain boundaries, flood profiles and floodway boundaries. This includes the contours developed from the 2003 LiDAR. All requested mes have been included with the comment responses. 6. The CLOMR application states that the topography used was the 2003 LiDAR from the effective FIS. However, the person who is assigned to review the CLOMR will not have access to this information. It is recommended that not only do you provide all the LiDAR information including the spatial files, but also the survey report (if available) to illustrate the topography data satisfies the FEMA guidelines and specs (Vertical Accuracy needs to be +/-98cm) The CLOMR application will be submitted to FEMA electronically through the online LOMC website. The FEMA submittal package will include some additional electronic materials that are required for the FEMA review which are not part of the package provided to the City. The digital materials will include work map mes such at the LiDAR contour data and digital SFHB linework. The survey report has not been included; however, the 2003 LiDAR data is the same data used for the effective FIS. The data was reviewed and approved by FEMA at the time of the effective FIS. 7. The CLOMR submittal requires a certified topography map. In order for this to be completed, a registered engineer or surveyor will need to certify the topographic work map they prepared using the 2003 LID AR data with a PE stamp. City of Spokane Valley Painted Hills PRD-Response Letter Stantec Comments March 8, 2019 Page 4 ofll A certified topographic map has been developed by WCE and will be provided with the CLOMR application. Ordinance lllitial Completeness This portion of our review has been organized by applicable Spokane Valley Municipal Code (SVMC) ordinance chapter. 1. Flood Plain Ordinance SVMC 21.30 So, Noted a. Plans. Screening Comment: Plans drawn to scale showing the general nature, location, dimensions, and elevations of the area in question have been provided. Reference: City of Spokane Valley -Painted Hills -CLOMR Review Initial Completeness Review b. Applicationmadeforallrelevant federal, state, and local permits. Screening Comments: 1. A draft application has been prepared for a Conditional Letter of Map Revision (CLOMR) for FEMA. Pending detailed review, it appears to be unnecessary to submit a CLOMR-F (CLO MR-Fill) application. Please see the completeness review specific to the CLOMR. The letter from Todd Whipple addressed to Henry Allen dated August 20, 2018, states that a CLOMR-Fis being sought, but the submittal package includes only a CLOMR application. The CLOMR-F language has been removed please see the revised Flood Control Narrative. ii. Plan title blocks imply that permits issued by the City of Spokane Valley will also be sought, and presumably permits will also be sought from Spokane County for portions of the project under Spokane County jurisdiction. However, a review of the submitted material does not include a draft or final version of a permit application to either entity. It appears that applications for the following local permits are missing: 1. Spokane Valley: Grading permit for placement of more than 50 cubic yardsoffill. An amended land disturbance permit was submitted to the City of Spokane Valley on August 20th 2018. A copy of the submitted application is attached. 2. Spokane County: Grading Permit for placement of more than 50 cubic yards of fill prior to issuance of a building permit. City of Spokane Valley Painted Hills PRD -Response Letter Stantec Comments March 8, 2019 Page 5 ofll A grading permit and a floodplain permit was submitted to Spokane County on October 14th 2016. A copy of the submitted application is attached. iii. The erosion and sediment control plan inclusion in the plan set indicates that the project proponents intend to comply with the requirement under the Washington Statewide Construction Stormwater General Permit to apply for coverage as a site disturbing more than one acre. This application process is generally done on-line within 60-90 days before construction is scheduled to begin, so application is premature at this time. We recommend written assurance that this is the project proponent's intent It is the intent of the project developer to follow all applicable requirements of the agencies that have jurisdiction over the property. 1v. Drywell registration documentation to the Washington Department of Ecology will be needed since part of the flood control strategy includes drywell installation. A table included in the project documentation would provide assurance of intent to comply with this requirement. Drywell registration is a condition of plan acceptance. It is anticipated that prior to the acceptance of the Flood Control Plan Set and the Gustin pipe plan Set that the proposed drywells will be registered and copies of the registration will be provided to the City of Spokane Valley and Spokane County. c. Watercourse maintenance, Screening comment: A watercourse operations and maintenance plan has been noted as "awaiting completion per jurisdiction comments" (p259, CLOMR application). The proposed operations and maintenance manual (0 &M) for the Home Owners Association has been drafted and previously submitted (October 14, 2016). With the completion of the EIS process, the O & M will be updated and submitted as a part of the Final Flood control plan approval. d. Public utility plans for water and sewer are included in the project package. So. Noted. e. Department of Ecology approval will be required for development in a floodplain. Although the DOE maintains oversight of the NFIP at the state level, to our knowledge they do not need to be part of the CLO MR process. CLOMR.s and LOMRs only require review and signatures from the local community's Floodplain Administrator prior to submittal to FEMA and DOE is generally not involved in that process. Other CLOMR.s and LOMRs within Washington have not required DOE specific approval provided the projects meet local community ordinances, which generally include state level NFIP requirements. City of Spokane Valley Painted Hills PRD -Response Letter Stantec Comments March 8, 2019 Page 6 ofll f. Demonstration that the project will not interfere with infiltration capacity is inherent in the design intent. It appears that a summary of the mounding analysis dated August 22nd 2017, of the infiltration gallery at the time, did not get included into the flood control narrative. The flood control narrative has been revised to include a summary of the mounding analysis and its potential for impact of adjacent stormwater facilities. g. Note that per SVMC 21 30.090, in the event the base flood elevation is increased by any amount, affected adjacent property owners must be notified, and provide their notarized approval. The detailed review will check if this provision applies; if it does apply, the applicants will be responsible for addressing this provision and they may be required to demonstrate compliance prior to any City approvals. The proposed project will not cause any increase in BFE for any adjacent properties. Since floodplain changes will occur offsite (reduced BFEs or removal ofFloodway) the required public notifications will be sent out by the City and County base on language we provide. 2. Critical Areas Ordinance SVMC 21.40 a. A critical area report is required. The document in the CLOMR application package includes a report titled, Painted Hills PRD, Biological Evaluation, Buffer Averaging, and Habitat Management Plan" that has many elements of a critical area report. However, it does not conform with. the requirements of a critical area report included in SVMC 21 .40. Specifically, a statement in the document that it was prepared to conform to SVMC 21.40 appears to be missing. The biological evaluation, Critical Area Report and habitat management plan has been revised. A Statement that the report was completed in conformance with SVMC 21.40 is included in the first page of the report. b. As impacts to the critical areas within the project limits are part of the project action, mitigation measures will be required. The report titled, Painted Hills PRD, Biological Evaluation, Buffer Averaging, and Habitat Management Plan" includes many components of a mitigation plan. Its contents need to reflect the requirements for a mitigation plan included in SVMC 21.40. Specifically, a cost estimate appears to be missing. The Erosion and Sediment Control Plan (ESCP) and what appears to be the critical areas mitigation plan are consistent. The biological evaluation, Critical Area Report and habitat management plan has been revised. An updated cost estimate has been included under section 10.0. c. A monitoring plan is required as part of the ordinance. It appears that a mitigation monitoring plan is included in the report titled, Painted Hills PRD, Biological Evaluation, Buffer Averaging, and Habitat Management Plan" includes many components of a monitoring plan. The monitoring plan must City of Spokane Valley Painted Hills PRD -Response Letter Stantec Comments March 8, 2019 Page 7 ofll comply with SVMC 21.40. The biological evaluation, Critical Area Report and habitat management plan has been revised. A monitoring plan has been included under section 9.0. So, Noted. d. Sureties. A surety is to be supplied. Typically, a surety is negotiated once the critical area report, maintenance plan, and monitoring plan have been accepted. e. Special Flood Hazard Area additional requirements must be included in the submittal package in accordance with SVMC 21 .40. Many of these requirements apply to content in the CLOMR application package. However, an index directing the reviewer and future users of the documents would make the package easier to use. So noted the Municipal Code Section 21.40.041 does apply primarily to the elements of the CLOMR as a whole a cover letter that may index each element, may be beneficial at the time of submittal. 3. Land Disturbing Activities SVMC 24.50 a. A grading permit is required under this ordinance, consistent with the requirement under Flood Plain Ordinance SVMC 21.30. Components of the grading permit application include: i. A completed permit application form; this is not included in the documents reviewed to date. ii. Two sets of plans, and two copies each of reports, specifications, and reporting documents. However, noting that the reviewed materials are all on electronic media, the requirement for a second set of documents is mitigated. iii. Erosion and Sediment Control Plans area included, as are geotechnical reports, a drainage report, and a SEP A checklist. The outline above is not intended to be a comprehensive review of the submitted documents with respect to the referenced ordinances. This review letter is intended to alert the project proponents to missing documents. Once all missing documents are supplied, a comprehensive and complete review can commence. An amended land disturbance permit was submitted to the City of Spokane Valley on August 20th 2018. A copy of the submitted application is attached. Hydrology Initial Completeness From a Hydrology standpoint, the fundamental question formulated based on a first pass review is this: A large pervious area currently allows infiltration in a distributed fashion into an underlying sand and gravel layer. The proposed development concentrates that flow and increases the volume by converting pervious to impervious, while allowing infiltration only at distinct locations. A series City of Spokane Valley Painted Hills PRD -Response Letter Stantec Comments March 8, 2019 Page 8 ofll of dry wells and gravel galleries are incorporated into the development to try to promote similar overall infiltration characteristics as the previously more pervious tract. The test pits and borings indicate a cover soil with silt, clay, etc. that might slow down surface infiltration. However, there seems to be a continuous and more pervious sand and gravel layer below that can accept anything that infiltrates through that top layer {assuming it doesn't have a limited capacity}. The geotechnical report alludes to the underlying groundwater being much deeper, but a full geologic section isn't provided. The proposed condition will likely have the same silt to clay type surface cover with the sand and gravel underlayment at a modest depth. In the absence of a more thorough regional hydrogeologic report, all of this leads me to conclude the infiltration approach can function, but the entire system is based on the assumed surface infiltration rates, the infiltration measures penetrating sufficiently through the surface to the underlying sand and gravel, and the assumption that the underlying more permeable layer is not conf"med and has excess capacity. I'm assuming the last point has been proven moot in this area, so the following questions are presented to get a better understanding of the importance of that infiltration rate and how it relates to the design assumptions and so we can compare those assumptions to the previous work prepared for the effective FEMA study: We are unsure of which report from the Geotechnical engineer you are referring to as there are a total of eleven (11) reports for the project, some of which have been revised per City comment. All of the Geotechnical reports compiled to date have been attached to this letter for easier reference these reports have been numbered 1-11. In regard to the underlying soil layers and flood control infiltration: Reports 1, 2, & 6 provide information to a depth from 15 feet deep test pits and 50 feet deep borings. dated December 31, 2013, October 14, 2014, and July 23 2016 respectfully. While Report 1 includes infiltration rates at a depth of 2.5 feet the design is based upon the additional exploration to the north. At the north end of the project site per Report 8 dated April 19, 2016 borings were completed to a depth of 50 and 75 feet once groundwater was encountered. The boring logs provide a sample of the underlying soils. Based upon this information a full depth drywell was installed and tested for infdtration. Report 9 dated August 21, 2017 (revised) established the infiltration rate of the north pond and gravel gallery. I. To help facilitate the review and to assure we aren't misinterpreting the design intent, please provide an annotated copy or copies of drawing sheet Cl .0 and Cl.3 with indications of flow directions, peak discharges, estimates of total runoff volumes, and infiltration rotes & volumes for a I 00-year, 24-hour duration standard storm event based on FEMA Effective Data, Corrected Existing, and Proposed Conditions. Reference points should be placed at flow path splits, structures, significant infiltration points, and hydraulically significant points within the study area. Providing the discharge and volume values in an accompanying table with corresponding point numbers is acceptable. The proposed infiltration facility design outflows are steady state and are not assumed to be volume limited. This follows the assumptions used in the effective FIS. Since inflows to the project site are being captured with infiltration facilities that exceed the peak discharges, there was no need to modify the HSPF model to model the proposed conditions. Accordingly, the requested information does not exist. Above ground storage areas included in the design are additional safety measures City of Spokane Valley Painted Hills PRO -Response Letter Stantec Comments March 8, 2019 Page 9 ofll that are above and beyond what is needed to infiltrate the FIS discharges and remove the project site from the floodplain. a. The purpose for the request is to help us perform a basic mass-balance and infiltration rate type review of the stonnwater runoff with and without development. While we understand the purpose, much of this work has been done in the IPEC mounding analysis Report 11. 2. An XP-SWMM model is provided for culverts under Madison Road. We request that this model be exported to EP A-SWMM format. The discharge values within the SWMM model will help with the hydraulic review. Export to EP ASWMM format requires a paid software extension that we do not own, therefore we cannot fulfill this request. We have provided some output flies with these comment responses and can provide other information upon request. 3. Several proposed storm water facilities on the site are designed with dry wells and gravel galleries to promote infiltration. The geotechnical data indicates these features may be effective if properly designed, installed, and maintained. For FEMA CLO MR purposes they seem to be assumed to fully function as designed and infiltration is not affected by antecedent conditions. For City review and long-term maintenance considerations, what happens if these facilities fail and sufficient infiltration no longer occurs? This could be due to excessively wet antecedent conditions, accumulation of sediment and debris, bioaccumulation and clogging, or other causes. Are any structures at risk? Do any of the proposed or existing roadways overtop? Any downstream impacts due to additional discharge leaving the site? a. If this information is contained in the provided data, it was not readily apparent from the initial review; in the response cover letter for the revised submittal, please highlight where this information is located within the submittal This information is touched on in the narrative and contained within the design and the design features of the flood control facility as shown on the plans. Within your assessment you considered failure based upon the failure of one or more of the items: excessively wet antecedent conditions, sediment, and debris. Debris: the transport of large vegetation within the floodwater from upstream of the facility. The floodwater flows over grassy fields at low velocity without a deep channel where large debris is typically transported. Any debris (brush grass or tree limbs) that are transported are conveyed through the 30' wide box culvert as detailed on sheet C5.10 into an open channel. At the end of the open channel is a headwall that includes two-48" concrete pipes. Over the entrance to these pipes are sloped trash racks. As floodwater rises vegetation floats and clears the opening of the two concrete pipes. In addition to the trash racks which can be cleared with an excavator bucket, during a flood event, any overflow of the floodwater out of the open channel will flow into the pond area before topping Thorpe Road. Any floodwater that enters the park area is stored and released via infiltration or overflow into a catch basin that is piped into Madison pipe. The O & M manual City of Spokane Valley Painted Hills PRD -Response Letter Stantec Comments March 8, 2019 Page 10 ofll includes the removal of debris from the flood control facility after an event. Sediment: the transport of suspended solids within the floodwater from upstream of the facility. As previously stated, the floodwaters flow across grassed fields with no distinct channel, thus limiting the transport of sediment. Within the WCE design as shown on sheets C5.20 through C5.22 The manholes include sumps that capture sediment. On sheet C5.30 the bioswale and sediment pond are shown. The tall grasses of the bioswale remove further suspended solids before the floodwater enters the settling pond. Within the settling pond velocities are further reduced to remove more suspended solids before the floodwater crests over a broad crested weir into the inf'lltration pond. Within the inf'Iltration pond on Sheet C5.31 the floodwater is essentially at a stand still as the water fdters through the treatment soil. If the pond inflow rate exceeds the infdtration outflow rate then floodwater slowly rises to rim of the drywells and enters the infiltration gallery on sheet CS.32 which has been shown to have a higher infiltration rate than the peak inflow rate of the model. The 0 & M manual includes the removal of sediment from the open channel, the Manholes the bioswale, the settling pond and the infiltration pond as needed on a flood event basis. Exces-sivelv wet antecedent conditions: A condition of oversaturated soil surfaces prior to a flood event, thus producing a volume and peak flow rate greater than that modeled by the FIS. It should be reiterated that the primary infiltration facility design inflow exceeds the FIS peak inflow for the 0.2% annual chance event (including the levee failure scenario), and further additional above ground storage has been incorporated into the design. While no facility can be designed for the ultimate unknown flood event that would require the evacuation of the residents in the area, the design does provide the means to rapidly reduce the volume of floodwater in the area. 4. It appears the proposed infiltration pond at the northern boundary of the site has been sized to contain a SO-year storm based on simplified runoff assumptions using the rational method. Fundamentally, what happens during a 100-year, 24-hour storm event with a higher peak discharge and runoff volume? Have discharge hydro graphs been developed and routed? Are the conveyance structures adequate to control that overflow? Similarly, if the basin does not provide sufficient infiltration, what structures are at risk? a. The same question would apply for the modifications to Storage Area #6. While the concept storm drainage report utilizes the 50-year storm event as the design volume to be held within localized swales and ponds and then discharged via drywells. The north pond is designed to hold and discharge an event greater than a 100-year flood event, understand that the 100-year flood event is larger than a 100-year 24 hr. storm event. As the storage areas #1 and #6 are the geographic low point of the area, and the creation of the ponds only shifts and lowers that point even further, there is no overflow route that does not exceed the Base Flood Elevation (BFE) in order for the water to flow to the Chester Creek channel. Therefore, there are no overflow routes or discharge hydrographs for these compensatory storage areas. As all structures are proposed to be placed 1 foot above BFE no structures are anticipated to be at risk. The questions above are pertinent to the initial completeness review and our overall understanding. During the detailed review phase of the project, we're planning to review the City of Spokane Valley Painted Hills PRD -Response Letter Stantec Comments March 8, 2019 Page 11 ofll HSPF model in greater detail and will document that review. So, noted Initial Completeness summary The applicant shall address all initial completeness questions and comments listed in the CLOMR, Ordinance and Hydrology Sections above and submit an updated floodplain permit application that includes all elements to the City of Spokane Valley for review So, noted please refer to the responses provided. If you have any questions or comments in regard to this response letter please feel free to contact us at (509) 893-261 7. Thank you Todd R. Whipple, P.E. TRW/bng Encl: City of Spokane Valley, Land Disturbance Permit 8-20-18 Spokane County Floodplain Development Permit 10-13-16 Spokane County Building Permit (Grading) 10-13-16 Revised Flood Control Narrative 3-5-19 BSW Revised BE, CAR, and HMP (within the Appendix of the narrative) IPEC Geotechnical Summary of Reports 1-11 ~ Stantec August 1, 2019 File: 2047071100 Attention: Henry Allen, PE Project Manager City of Spokane Valley 10210 E. Sprague Ave. Spokane Valley, WA 99206 Dear Mr. Allen, Stantoc Consulting Services Inc. 621 West Mallon Avenue Suite 309, Spokane WA 99201-2181 Reference: City of Spokane Valley-Painted Hills Development CLOMR, Ordinance, & Hydrology/ Hydraulics Detailed Review, Update The City of Spokane Valley (City) has contracted Stantec Consulting Services Inc. (Stantec) to perform an independent technical review of an application for a Conditional Letter of Map Revision (CLOMR) and related technical documents associated with the Proposed Painted Hills Development project. Under an intergovernmental agreement with Spokane County (County), the City has directed Stantec to also perform an independent technical review of County-related documents associated with the Proposed Painted Hills Development project. The proposed development is located along Chester Creek near the intersections of Dishman-Mica Road, Thorpe Road, and Madison Road to the south of the City. The subject tract of land was historically a low-lying flood-prone area that was used as a golf course. The proposed development will place a significant amount of fill in the area to facilitate construction of residential, multi-family residential, commercial, and passive open-space areas. An infiltration pond and an extensive set of drainage improvements is proposed to manage stormwater runoff and reduce associated flood risks to acceptable levels. The CLOMR application and related documents were prepared and assembled by Whipple Consulting Engineers (WCE). Stantec reviewed the original supporting documentation provided by the City and issued a letter detailing our "Initial Completeness Review'' on December 17, 2018. WCE responded to the Stantec Initial Completeness Review by letter dated March 8, 2019 and has provided a revised narrative and additional data for consideration. Stantec has reviewed this additional information and has prepared this letter to document our observations. In summary, based on the scope of our review, WCE's proposed engineering design appears to be consistent with City, County and FEMA requirements. However, we did find features of the proposed design that require additional information or analysis. Also, it is understood that this review was an overall completeness and methodology-based review, while it is the responsibility of the engineer of record (WCE) to certify the design is correct, appropriate, and all applicable design and permitting requirements have been met. This letter outlines the topics Stantec reviewed, the observations that were made, and identifies a number of items the applicant (WCE) will be required to provide to the City, County and/or FEMA as a part of the continuing construction permitting process. August 1, 2019 Henry Allen, PE Page 2 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology/ Hydraulics Detailed Review In the sections that follow our signature block, you will find Stantec's documentation for the Detailed Review. The following sections are organized to follow the same outline used in the Initial Completeness Review, beginning with the CLOMR, then followed by Ordinances (including applicable Spokane County Ordinances), Hydrology, and now Hydraulics. We've also added a section following Hydraulics that addresses the detailed City comments and WCE responses in WCE's August 20, 2018 submittal and their status with respect to the March 6, 2019 WCE submittal. Responses requiring additional follow-up by project proponents are flagged with this symbol: All other new comments -those that do not require follow-up -are flagged with this symbol: ✓ Balded, italicized text indicates documents referred to by the project proponents that we were unable to locate in the submitted material. We hope this information meets your needs with respect to the Proposed Painted Hills Development and will help facilitate moving forward with an appropriate course of action for the project. Please don't hesitate to contact us should you, or WCE, have any comments or questions related to our work. Regards, Stantec Consulting Services Inc. Erman Caudill, PE (KY #23451 ), CFM Senior Engineer, Water c:~(!A Russ Connole, PE Senior Project Manager Alan Gay, PE Associate, Senior Engineer August 1, 2019 Henry Allen, PE Page 3 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology/ Hydraulics Detalled Review 1 CLOMR DETAILED REVIEW For the previous submittal, Stantec relied on the WCE "Painted Hills Flood Control Development Narrative" dated August 20, 2018 and "DRAFT CLOMR Application for the Proposed Painted Hills Developmenf' that was prepared by West Consultants Inc. and dated August 16, 2018. Stantec had several comments during the Initial Completeness Review related to understanding the proposed conditions and relating the design to most current proposed configuration. 1. There were numerous documents provided. It was assumed that the document "CLOMR Applicaton for the Proposed Painted Hills Development" would be the narrative provided to FEMA for the CLOMR review, but it is unclear whether or not the other information will be part of the submittal. A lot of information is provided in the "Painted Hills Flood Control Development Narrative", but it is uncertain whether this document will be submitted to FEMA or not. It is recommended that a more clear and easy-to-follow narrative be submitted to FEMA. The review for FEMA will be conducted by personnel unfamiliar with the project and therefore, the information should be presented in such a way that the project narrative, purpose and details can be easily followed and understood. WCE response: The WCE Flood Control Narrative has been revised, and included with this submittal. ✓ The revised CLOMR narrative has been reviewed. The revised "Painted Hills Flood Control Development Narrative" by WCE dated March 6, 2019 provides a slightly better explanation of the proposed configuration from a hydrologic stance and will be instrumental in FEMA's review process for the CLOMR application. The West Consultants CLOMR Application document provides the critical support data for the FEMA review of the CLOMR. Much of the additional information is support data for the proposed design and for FEMA purposes should be indicated as such. a. If both documents are to be submitted, it is recommended that language referring to the submittal as a CLOMR-F be revised. From the initital completeness review, it appears the analysis that is provided in the package will revise the floodplain mapping for three detailed studies, including the removal of Unnamed Tributary to Chester Creek. Therefore, a CLOMR is required which will establish new flood hazard mapping. With the new floodplains established, a CLOMR-F may not be required since the the properties will not be within the new, effective Base Floodplain established in the CLOMR. WCE response: The application being provided to FEMA is a CLOMR. The WEST authored report titled: CLOMR Application for the Proposed Painted Hills Development is the primary explanatory report associated with the CLOMR. The MT-2 Forms included in the report also report the application as a CLOMR. Some WCE materials which are provided as CLOMR report appendices inadvertently referred to a CLOMR-F rather than a CLOMR. Rather than revising all of the supplemental WCE materials, they will provide a letter to the communities clarifying that references to a CLOMR-F should be considered as just a CLOMR. Since the primary CLOMR report and the MT-2 forms correctly reference a CLOMR, we believe this will be appropriately clear for the FEMA reviewer. August 1, 2019 Henry Allen, PE Page 4 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology/ Hydraulics Detailed Review ✓ The WCE response provides sufficient clarification regarding the project proponents intent for the CLOMR application to FEMA. 2. The MT-2 Forms and the "CLOMR Applicaton for the Proposed Painted Hills Development" indicate that no change to the hydrology was completed for this task. The CLOMR Application also does not have a detailed write-up of the hydrology. It is Stantec's understanding that the basis of the floodplains being removed from this location is a combination of fill and new infiltration basins. Given the infiltration basins are part of the hydrologic analysis and used a hydrologic program HSPF, it is recommended that a detailed narrative be added discussing the changes to the original Flood Insurance Rate Map (FIRM). For example, initial completeness review inticates that Unnamed Tributary to Chester Creek is being removed from the Flood Hazard mapping. Is the removal based soley upon fill or has the addition of infiltration basins removed floodplain? As stated previously, the FEMA reviewer will not have previous knowledge of the project or the methodologies and procedures used for the analysis. WCE Response: It should be noted that the FIS HSPF model was not modified for this CLOMR. The CLOMR report has been updated to better clarify this fact. The main WCE facility is designed to have a peak design outlaw discharge that exceeds the 0.2% annual chance FIS inflows. Since the facility capcity exceeds the inflows, there is no remaining ponded water in the project site under the proposed design. Accordingly, no modifications were needed for the hydrologic model. The lower portion of the Unnamed Tributary is being removed from the floodplain based on the proposed infiltration facilty in Storage Area (SA) 6. This is described on Page 11 of the CLOMR report. The facilty (storage and infiltration) can contain the 0.2% annual chance flood. The left overbank flowpath for the Unnamed Tributary is based on failure of the levee on the left overbank between Highway 27 and the storage area. Since that portion of the channel will be conveyed via a culvert in the proposed design, there is no need for a without levee scenario. Accordingly, the removal of the left bank overflow path and the main flowpath of the Unnamed Tributary are based on a combination of a proposed culvert and the proposed infiltraiton facilty in SA6. Additional text describing this has been added to the CLOMR report. ✓ The WCE response regarding the Flood Insurance Study (FIS) modeling is sufficient and is supported by the detailed review of the hydrologic and hydraulic models discussed in greater detail in sectons 3 and 4 of this review letter. 3. CLOMRs require the submittal contain example documentation of legal notice to be sent to all affected property owners within and outside of the the City's jurisdiction, explaining the impact of the proposed action on their property. No documentation was found. WCE Response: Property owner notifications are required prior to submittal to FEMA and the process for this has been discussed previously with the City and County during prior submittal and reviews of the CLOMR application. This project has been going on for some time and has undergone several changes during back and forth review and discussions between WCE and the City and County. Since the design has been evolving based on these discussions, in order to avoid public confusion, we are waiting until the City and County review is complete and we have agreement upon the proposed plan. At that point the final notification text will be provided to the August 1, 2019 Henry Allen, PE Page 5 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology/ Hydraulics Detailed Review communities who will place the text on letterhead and mail to the appropriate property owners. The notifications will be mailed either prior to or coincident with submittal to FEMA. ✓ The proposed solution has been reviewed with City of Spokane Valley and Spokane County staff. Both communities are in agreement with this approach. 4. CLOMR submittal guidance states that in locations where sediment transport affects hydrology, the effects of sediment transport should be considered in the hydrology and Section F of Form 3 should be submitted. Will sediment have an impact to the infiltration basins? Documentation should be provided in the narrative stating whether or not sediment will have an impact and if so, how it will be mitigated. WCE Response: The inflows to the Thorpe Box Culvert and the main infiltration facility flow through grassy fields, with no physical channel, at low velocities (average 1.5 ft/s). Due to the low velocities, combined with the natural filtering effects of the vegetation, it is not expected that sediment will have significant impacts to the infiltration facilities. Additionally, the proposed design by WCE also includes sumps within Manholes, a biofiltration swale, a settling pond and overflow weirs into drywells to allow for settlement of sediment prior to entering the gravel gallery under the infiltration pond. The inflow to the Storage Area 6 infiltration facility flows through a grassy channel, at low velocity (average ~3 ft/s). It is similarly expected that the low velocities and filtering effects of the vegetation will minimize sediment transport into the facility. A similar design with sumps in manholes and overflow weirs into the drywalls allows for settlement of sediment prior to entering the drywells of the Triangle Pond. Finally, WCE has developed a grading plan of the site that keeps the finish floor of all proposed structures 1 foot above the Base Flood Elevation (BFE). And WCE has developed an Operations and Maintenance Plan for the facility to ensure the facilities receive regular maintenance and inspections to minimize the long-term effects of sediment that may enter these infiltration systems. ✓ The response from WCE indicates that sediment transport, settlement, and removal has been considered. A review of the Painted Hills Flood Control Development Narrative revised March 6, 2019, indicates the elements in WCE's response paragraphs are included, and a draft Operations and Maintenance (O&M) Plan was made available for review. It is understood that a final O&M document may be held back until the Draft Environmental Impact Statement (EIS) has been released. Comments on the adequacy of the draft O&M Plan are addressed further in a later sections (2.1 and 5.4) of these comments. 5. No shapefiles or CAD files were provided. Spatial files representing the following are required: a. New cross-sections and profile centerlines for the new hydraulic model and results; b. New floodplain boundaries; August 1, 2019 Henry Allen, PE Page 6 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology / Hydraulics Detailed Review c. All of the data used in determining the revised floodplain boundaries, flood profiles and floodway boundaries. This includes the contours deleveloped from the 2003 LiDAR. WCE Response: All requested files have been included with the comment response. ✓ A review of the submitted documents indicates that the above information has been included or addressed as appropriate. 6. The CLOMR application states that the topography used was the 2003 LiDAR from the effective FIS. However, the person who is assigned to review the CLOMR will not have access to this information. It is recommended that not only do you provide all the LiDAR information including the spatial files, but also the survey report (if available) to illustrate the topography data satifies the FEMA guidelines and specs (Vertical Accuracy needs to be +/-98cm). WCE Response: The CLOMR application will be submitted to FEMA electronically through the online LOMC website. The FEMA submittal package will include some additional electronic materials that are required for the FEMA review which are not part of the package provided to the City. The digital materials will inlcued work map files such as LiDAR contour data and digital SFHB linework. The survey report has not been included; however the 2003 LiDAR data is the same data used for the effective FIS. The data was reviewed and approved by FEMA at the time of the effective FIS. ✓ The response provides sufficient indication that the underlying data used in preparing the electronic models supporting the CLOMR application are acceptable to FEMA, and therefore acceptable to the City of Spokane Valley and Spokane County. 7. The CLOMR submittal requires a certified topography map. In order for this to be completed, a registered engineer or surveyor will need to certify the topographic work map they prepared using the 2003 LiDAR data with a PE stamp. WCE Response: A certified topographic map has been developed by WCE and will be provided with the CLOMR application. ✓ A review of the submitted materials includes topographic maps of the project area signed and stamped by a Washington-licensed professional land surveyor. 2 LOCAL ORDINANCE DETAILED REVIEW This portion of our review has been organized by applicable Spokane Valley Municipal Code (SVMC) ordinance chapter and Spokane County Code (SCC) ordinance chapter. Stantec provided comments with the Initial Completeness Review and WCE responded. For brevity, only those items with outstanding issues or where Stantec has provided additional comments have been included herein. August 1, 2019 Henry Allen, PE Page 7 of 76 Reference: City of Spokane Valley-Painted Hills Development CLOMR, Ordinance, & Hydrology/ Hydraulics Detailed Review 2.1 FLOODPLAIN ORDINANCE SVMC 21.30 c. Watercourse maintenance, Screening comment: A watercourse operations and maintenance plan has been noted as "awaiting completion per jurisdiction comments" (p259, CLOMR application). WCE Response: The Proposed operations and maintenance manual (O&M) for the Home Owners Association has been drafted and previously submitted (October 14, 2016). with the completion of the EIS process, the O&M will be updated and submitted as a part of the final flood control plan approval. -+ The final version of the watercourse O&M plan must be provided for review before ordinance compliance review can be completed. The submitted documents include a section titled, "Operations and Maintenance Plan For Painted Hills PRD Flood Control System". (PRD is defined as "Planned Residential Development") This section of the submittal appears to address ownership, purpose, describes the general drainage facility layout and function, and includes maintenance requirements and schedule for the drainage facilities, including the box culvert, Chester Creek and levee, concrete channel, storm drain mainline, manholes and catch basins, cross culverts under Madison Road, the bio-infiltration swale, and the drywells and gravel gallery. It also includes a section addressing financing, describing the annual maintenance fund and resulting estimated cost per lot. These items address basic O&M requirements for a Home Owner's Association (HOA). In its capacity as the entity ultimately responsible to assure continued maintenance and operability of the flood management facilities per 44 CFR Part 65.6(a)(12) and City Ordinance 21.30.070.D.7.b, the City may require the project proponents and/or their successors fund a professionally-managed maintenance and operations entity. A detailed review is also included in section 5.4 of this letter, comments 13-17. Once the official copy is submitted for review, it will be evaluated. d. Department of Ecology approval will be required for development in a floodplain. WCE Response: Although the DOE maintains oversite of the NFIP at the state level, to our knowledge they do not need to be part of the CLOMR process. CLOMRs and LOMRs only require review and signatures from the local community's Floodplain Administrator prior to FEMA and DOE is generally not involved in that process. Other CLOMRs and LOMRs within Washington have not required DOE specific approval provided the projects meet local community ordinances, which generally include state level NFIP requirements. -+ The ordinance requirement in 21.30.070.D.7.a is for the City to notify adjacent communities -in this case Spokane County -and the Department of Ecology prior to any alteration or relocation of a watercourse, and submit evidence of such notification to the Federal Insurance Administration. As a result, the City may require additional information from the project proponent if Ecology requests such information from the City. 2.2 CRITICAL AREAS ORDINANCE SVMC 21.40 (2010 VERSION) ✓ The Critical area report, titled, "Biological Evaluation, Critical Areas Report, and Habitat Management Plan" (Biology Soil & Water, Inc., updated February 28, 2019) has been reviewed August 1, 2019 Henry Allen, PE Page 8 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology/ Hydraulics Detailed Review against the version of SVMC 21 .40 in effect at the time of vesting in 2014. The Critical Area Report is in conformance with the requirements in that document. 2.3 LAND DISTURBING ACTIVITIES SVMC 24.50 ✓ The City of Spokane Valley Land Disturbance Permit Application has been reviewed and appears complete. As noted above, it is supported by the project plans and documents in the CLOMR application package. 2.4 FLOOD DAMAGE ORDINANCE SCC3.20 2.4.1 3.20.230 Critical Facilities requires "(2) Construction of new critical facilities shall be located outside the limits of the 500-year floodplain when identified on the community's Flood Insurance Rate Map (FIRM), except when no feasible alternative site is available. Critical facilities shall have the lowest floor elevated to or above the level of the 500-year frequency flood. Floodproofing and sealing measures shall be taken to ensure that toxic substances will not be displaced by or released into floodwaters." Critical facilities are defined as, " ... a facility for which even a slight chance of flooding would be too great. Critical facilities include, but are not limited to, schools, child care facilities, hospitals, police, fire and emergency response installations, nursing homes, or installations which produce, use, or store hazardous materials or hazardous waste." ✓ Reviewing the applicants' submitted materials, it does not appear that any Critical Facilities are planned for inclusion in the 500-year (0.2% annual recurrence probability) floodplain area. Also, item (3) states, "Access routes shall be elevated to or above the level of the 500-year frequency flood to the extent possible." ✓ A review of the Revised Flood map in the Painted Hills CLOMR Draft compared with the PRO plan set, indicates that the travelled ways in Spokane County's jurisdiction will be outside of the 500- year frequency flood area. However, a version of the proposed condition flood map with the proposed street layout would be very helpful in facilitating any future reviews. 2.4.2 3.20.300 Flood plain development permit required/3.20.310 Application for Floodplain Development Permit. ~ A Spokane County Floodplain Development Permit Application is included with the March 6, 2019 submittal. A review of that document, signed 10/13/16 by Brian Walker of Black Realty, Inc., indicates the application was only for the water-related construction. It includes watercourse alteration and fill material used for water-related construction. As Base Flood Elevation has been established for the area in question, Section F requirements apply. The requirement there is for a surveyor licensed in the State of Washington to stamp and sign the site plan. The Flood Control site plan topographic maps have been stamped and signed by Jon A. Gordon, PLS. However, those maps, in particular Sheet C1 .0 covering the area under Spokane County jurisdiction, do not show the floodplain boundary, nor is there a temporary benchmark with elevation shown. August 1, 2019 Henry Allen, PE Page 9 of 76 Reference: 2.4.3 City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology/ Hydraulics Detailed Review 3.20.340(2)(c) ✓ The requirement for hydrologic and/or hydraulic modeling studies from development proponents showing the impact of the proposed development on the base flood elevation has been met. -+ Note that 3.20.340(3) requires a certification of the actual elevations showing project compliance with floodplain development permit conditions and requirements for residential structures, stamped and signed by a licensed land surveyor registered in the State of Washington. 2.4.4 3.20.340(5) requires that maintenance be provided within the altered or relocated portion of the watercourse so that the flood-carrying capacity is not diminished. A written maintenance agreement for this purpose shall be required and the County Engineer may require the agreement to be recorded. The submitted documents include a statement in the CLOMR Application in Appendix J, "Note: O&M Plans awaiting completion per jurisdiction comments.". -+ An official O&M Plan is needed for review. However, the submitted documents include a section titled, "Operations and Maintenance Plan For Gustin Ditch Flood Control System". This section of the submittal appears to address ownership, purpose, describes the general drainage facility layout and function, and includes maintenance requirements and schedule for the drainage facilities, including the drainage culvert, conveyance channel referred to as a 3 foot bottom width ditch, a levee along the south side of the ditch, the existing gravel pit, referred to elsewhere as Triangle Pond, and 18 drywalls to be installed in Triangle Pond. It also includes a section addressing financing, describing the annual maintenance fund and resulting estimated cost per lot. It appears the required elements of an HOA-based O&M plan have been addressed. However, Spokane County, per 44 CFR Part 65.6(a)(12) and Spokane County Code 3.20.340(5)(b) may require the project proponents and/or their successors fund a professionally-managed maintenance and operations entity to maintain the proposed Gustin Ditch flood control system. Once the official version of the O&M Plan has been submitted, it will be reviewed. 2.4.5 3.20.510 Anchoring. All new development and substantial improvements shall be anchored to prevent flotation, collapse or lateral movement of the structure or works. ✓ A review of the submitted flood control plans indicates engineered slope and watercourse stabilization measures for piping, infiltration areas, and embankments are to be constructed. The PRO road improvements in the flood plain are not in Spokane County's jurisdiction. 2.4.6 3.20.520 Construction Materials and Methods. ✓ The same comments noted for 3.20.510 apply to this section. 2.4. 7 3.20.530 Utilities. ✓ No water supply wells or on-site waste disposal systems are proposed. Standard construction details for water and sewer systems have been provided; if current standard construction practices are followed during construction, infiltration of floodwaters into the water and sewer systems should be minimal. 0 • v 'l v,i:h <:01 11 wi"I, In ,,11r1 I August 1, 2019 Henry Allen, PE Page 10 of 76 Reference: 2.4.8 City of Spokane Valley-Painted Hills Development CLOMR, Ordinance, & Hydrology / Hydraulics Detailed Review 3.20.540 Subdivision and Other Proposed Developments. ✓ The PRD plans for buildings anticipated to be in areas subject to flooding during a 1-percent- annual-chance flood event are not in Spokane County's jurisdiction, 2.4.9 3.20.550 Review of Building Permits. ~ A building permit application work sheet was submitted with the March 6, 2019 submittal set. The application is for grading. 5,100 cubic yards of native soil fill are noted on the application. Under "Additional Site Information", The box for "Are there any wetlands, streams or ponds within 200 feet of the property?" Is marked, "no". However, the Unnamed Tributary to Chester Creek identified on the Flood Insurance Rate Map is on parcels 45344.9108, and 45343.9052 according to sheet P1 .3 of the PRD plans. Also, on the same form, the box for "Are there slopes greater than 30% on the property? Is marked "no", but the borrow pit on parcel 45343.9052 appears to have slopes with a drop of 30-feet in 46 horizontal feet. 2.4.10 3.20.610 Residential Construction. ✓ No residential construction is planned for the project in the area under Spokane County jurisdiction. 2.4.11 3.20.620 Nonresidential Construction. ✓ No occupied structures are planned for the project in the area under Spokane County jurisdiction. 2.4.12 3.20.630 Manufactured Homes and 3.20.640 Recreational Vehicles. ✓ No manufactured homes or recreational vehicle parking areas are planned for siting on the project. 2.4.13 3.20.650 Encroachments. ✓ No increase in water surface elevation is modeled for the areas within Spokane County jurisdiction. 2.4.14 3.20.660 Floodways. ✓ No floodways, either existing or proposed within the project are within the project improvement area and within Spokane County jurisdiction, except the inlet to the Chester Creek culverts at Thorpe Road. The project hydrologic and hydraulic analyses include the subject culverts, demonstrating that the culverts have been designed to carry the 1-percent-annual-chance flood event, and not result in an increase in base flood discharge. 2.4.15 3.20.690 Special Requirements, Flood Storage Areas. ✓ The flood storage area designed for parcel 45343.9052 has a study and design prepared by a Washington-licensed professional civil engineer, that shows the proposed flood storage area will have sufficient capacity to store and infiltrate floodwaters for the 1 percent annual chance flood event. August 1, 2019 Henry Allen, PE Page 11 of76 Reference: City of Spokane Valley-Painted Hills Development CLOMR, Ordinance, & Hydrology/ Hydraulics Detailed Review 2.5 CRITICAL AREAS ORDINANCE SCCl 1.20 2.5.1 11.20.030 Allowable Uses and Activities within Wetlands, Fish and Wildlife Habitats, and Geo- Hazard Areas. ✓ The proposed filling of greater than 50 cubic yards (5,100 cubic yards) is classified as a limited use in all three critical area categories. The proposed use as a stormwater detention/disposal facility is also limited. Under the 11.20.030.C process flow chart, additional information is required. The project proponents have prepared a Biological Evaluation, Critical Areas Report, and Habitat Management Plan (Biology Soil & Water, Inc., February 28, 2019). Protection measures have been proposed in this document. 2.5.2 11.20.050 Wetlands. ✓ According to the information presented by the project proponents, no wetlands are on the project site within Spokane County jurisdiction. The project proponents concluded that the waters from the Unnamed Ttributary to Chester Creek crossing Spokane County jurisdiction being piped to the borrow pit infiltration basin in parcel 45343.9052 result in no impacts to regulated waters, so no mitigation is required. 2.5.3 11.20.060 Fish and Wildlife Habitat Conservation Areas. ✓ No wildlife priority habitat areas are concluded to be impacted by the project within Spokane County's jurisdiction. However, an east-west 1 O+ acre travel corridor is to be preserved by the developer for wildlife travel across the site by white-tailed deer, elk, and gray wolf. 2.5.4 11.20.070 Geologically Hazardous Areas. ✓ The project's Biological Evaluation, Critical Areas Report, and Habitat Management Plan did not address geologically hazardous areas. However, several geotechnical reports and addenda have been prepared for the project and have been provided by the project proponents. Among the criteria for geologically hazardous areas are slopes greater than 30%, soils identified by the NRCS as having a sever potential for erosion, both of which are present in the project area within Spokane County jurisdiction. 2.5.5 11.20.070.C. Regulations. Spokane County Erosion Control requirements apply. ✓ Project proponents have prepared a Storm Water Pollution Prevention Plan/Erosion Control Plan (SWPPP/ECP) for the areas to be disturbed by the project within Spokane County jurisdiction. It does not appear that plan sheet C5.1, the site plan showing the location of the improvements, includes the locations of the selected Best Management Practices (BMPs) included in the SWPPP/ECP. C5.1 does callout side slope seeding using a grass seed specified on the plan. It is unclear if the steeper slopes of the north face of the borrow pit are intended to be seeded. It does not appear that area is intended for regrading to reduce slope steepness, calculated to be 65% (approximately 1V: 1.5H). A review of the site soils per NRCS web soil survey shows it to be "Urban land-Springdale disturbed complex. Springdale gravelly complex soils in the 11.20.090 Appendix L are shown to have a severe erosion potential. Using the universal soil loss equation August1,2019 Henry Allen, PE Page 12 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology / Hydraulics Detailed Review estimate confirms a severe erosion potential. Though sediment will be trapped within the borrow pit, it may be prudent from a safety and long-term maintenance perspective for the project proponents to address the erosion potential of the north face slope of the borrow pit. 2.6 MOUNDING ANALYSIS REPORT AUGUST 22, 2017, PREPARED BY IPEC, STAMPED BY PAUL T. NELSON. ✓ No comment. Conclusions appear to be supported by calculations. 3 TECHNICAL REVIEW OF HYDROLOGIC DATA ✓ WCE's response to Stantec's Initial Completeness Review dated March 8, 2019 adequately addresses the hydrologic questions posed. A more thorough review of site hydrologic conditions, proposed stormwater management features, and the indication that all structures will be placed at least 1 foot above the base flood elevations was instrumental in resolving those questions. Summarizing our understanding of the hydrologic design: WCE used hydrologic discharge data from the prior effective report by West Consultants Inc. ("Flood Insurance Study Hydrologic Analysis for Chester Creel<', West Consultants, Inc. December 8, 2004). No changes to FEMA Effective Discharge Values are proposed. The channel and culverts along the east side of the site, generally parallel to the west side of Madison Road, are designated in the FEMA "Flood Insurance Study for Spokane County, Washington (53063CV000A)" dated July 6, 2010 as the "Chester Creek Golf Course Overflow" reach. The published 1-percent-annual-chance discharge for the reach is 64 cubic feet per second (cfs). WCE assumed this discharge plus a 27 cfs overflow from Chester Creek (91 cfs total) as inflow for the proposed box culvert beneath Thorpe Road and a short section of concrete channel near the intersection of Thorpe Road and Madison Road. The existing channel that flows north along the west side of Madison Road will be replaced with a dual 48-inch pipe culvert arrangement that will convey the 91 cfs from the south plus an additional 15 cfs (106 cfs total) from five 18-inch culverts that enter from the area east of Madison Road. The bioswale and infiltration pond receive discharge from the outlet of this pipe system. The reported capacities of these features are as follows: -Box culvert (30'W x 3'H) beneath Thorpe Road= 216 cfs -Dual 48-inch pipe culverts = 154 cfs -Bioswale = 269 cfs -Infiltration trenches in the pond = 162 cfs WCE cites a number of geotechnical studies and reports to conclude the proposed infiltration pond, gravel gallery system, and related features can infiltrate at least as much as the existing site features. However, regarding infiltration capacity, these reports and the provided calculations all reference a single full-scale drywell test conducted by IPEC on May 6, 2016. August 1, 2019 Henry Allen, PE Page 13 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology/ Hydraulics Detailed Review WCE also cites an October 14, 2014 IPEC report using the Spokane 200 Method to calculate that the Triangle Pond drywells will each have a capacity of 1 cfs. ✓ The hydraulic design discharge capacity of the proposed features appears to be adequate when compared to the effective discharges. The revised narrative provides a description of the assumptions used by WCE and will be instrumental in the CLOMR application. -+ The infiltration rate in the discussion contained in the revised WCE narrative on narrative page 5 of 6 under the heading "Bio-infiltration pond" doesn't agree with the value used in the Gravel Gallery Cale Sheet in the attachments. Reviewing the backup data provided in Report 9, the Full-Scale Drywall Testing, dated June 28, 2016, and the August 21, 2017 supplement, IPEC's data shows a drywall capacity of 0.149 to 0.151 cfs. Using the SRSM approach from Appendix 4B, IPEC proportioned the qa, allowable flow, to be 1.15 cfs; using a factor of safety of 1.1 appropriate to the very low fines passing the No. 200 sieve, one arrives at the recommended drywell infiltration flow rate of 1.05 cfs for design, which when divided by the typical 600 square feet of drywall infiltration area yields a design infiltration rate of 1.8 x 10-3 cfs/square foot. This infiltration rate value is carried forward to the WCE Gravel Gallery Cale Sheet used to calculate the gravel gallery design capacity of 162.64 cfs, including direct infiltration in the gravel fill itself of 116.92 cfs. In the System Summary section of the narrative, the 61,000 square foot bio-infiltration pond is said to have a discharge rate of 1.6 x 104 cfs/sf, for a total infiltration capacity of 9. 76 cfs. The difference of 105.26 cfs is the bulk of the infiltration capacity claimed for the system. Reviewing the detailed design on sheets C5.31 and C5.32, the gravel gallery section for the drywells shows gravel to 18- feet deep, with perforated 12" pipe extending 1 0'from the bottom of each drywell barrel. This is consistent with the Gravel Gallery Cale Sheet parameters. Project proponents will need to reconcile the narrative with the calculations and plans. -+ It is recommended that WCE validate and/or justify the assumptions that the infiltration rate from the May 6, 2016 dry well test is applicable to the gravel gallery area since the areas appear to be separated by 230 feet. -+ If the project proponents wish to claim on-site storage as the backup for infiltration in handling the design flooding event, it is further recommended that WCE provide a volumetric analysis demonstrating that sufficient storage is provided to keep flood elevations below the proposed base flood elevations and that corresponding structure elevations are still appropriate if the proposed infiltration rate were to be unrealized or substantially decline. -+ Though the August 21, 2017 supplement to IPEC Report 9 includes a Figure 3 map indicating the drywell location, there isn't a reference on Figure 3 or elsewhere to locate Figure 3 in relation to the rest of the project; from Sheet P3.0 compared to sheet C1 .1 of the Flood Control plan set, it appears this existing drywell was located approximately 230 feet west of the west end of the proposed Gravel Gallery. The Completeness review letter dated December 17, 2018 requested on p7, item 1, " .. please provide an annotated copy or copies of drawing sheet C1 .0 and C1 .3 with indications of flow directions, peak discharges, estimates of runoff volumes, and infiltration rates and volumes for a 100-year, 24 hour duration standard storm event base on FEMA Effective Data, Corrected Existing, August 1, 2019 Henry Allen, PE Page 14 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology / Hydraulics Detailed Review and Proposed Conditions. Reference points should be placed at flow path splits, structures, significant infiltration points, and hydraulically significant points within the study area. Providing the discharge and volume values in an accompanying table with corresponding points numbers is acceptable." WCE Response: The proposed infiltration facility design outflows are steady state and are not assumed to be volume limited. This follows the assumptions used in the effective FIS. Since inflows to the project are being captured with infiltration facilities that exceed the peak discharges, there was no need to modify the HSPF model to model the proposed conditions. Accordingly, the requested information does not exist. Above ground storage areas included in the design are additional safety measures that are above and beyond what is needed to infiltrate the FIS discharges and remove the project site from the floodplain. ✓ As noted above, the infiltration capacity claimed for the project appears to be at least partially supported. The backup claim is that should infiltration prove insufficient, then the storage volume will be "additional safety measures" that would store enough flood water to prevent a rise in the flood elevation above the established BFE. See recommendation above beginning, "If the project proponents wish to claim ... " -+ Please note the FEMA CLOMR review team may have additional questions, comments, and or request additional data in order to better understand the existing and proposed configurations. ✓ The revised WCE narrative does not include discussion of the design discharges on the main body of Chester Creek. Based on the West Consultants DRAFT CLOMR application it appears these values are not being revised and are consistent with the FEMA FIS (116 cfs near Thorpe Road), but clarification to the WCE front end narrative is recommended prior to submitting to FEMA as a part of the CLOMR application. If a discharge other than 116 cfs was used to design the channel geometry near the intersection of Thorpe Road and Dishman-Mica Road, further review is warranted. 4 TECHNICAL REVIEW OF HYDRAULIC DATA As previously mentioned, the revised "Painted Hills Flood Control Development Narrative" by WCE dated March 6, 2019 will be instrumental in FEMA's review process for the CLOMR application. That narrative essentially serves as a summary for the West Consultants Inc. CLOMR Application document, which provides the critical support data for the FEMA review of the CLOMR. Much of the additional information provided is support data for the proposed design and for FEMA purposes it should be indicated as such. ✓ For CLOMR purposes, the screening review recommended the previously submitted "DRAFT" CLOMR Application for the Proposed Painted Hills Development" by West Consultants Inc. dated August 16, 2018 be revised to reflect the latest proposed configuration and results without extraneous information. References to options that include levees or a CLOMR-F have been removed in the currently submitted "DRAFT" CLOMR. ✓ The revised WCE narrative clearly explains the design assumptions and revised geometry for the proposed development. The West Consultants CLOMR Application document provides hydraulic support data. The hydraulic design data and provided CLOMR application data reviews generally r,a l'jll -::1;)1 CCllril ll/r,il ll"I ,wr, I August 1, 2019 Henry Allen, PE Page 15 of 76 Reference: City of Spokane Valley-Painted Hills Development CLOMR, Ordinance, & Hydrology / Hydraulics Detalled Review did not identify any hydraulic design elements for the proposed development that appeared to be fundamentally flawed from a technical stance. The FEMA review team responsible for the CLOMR application may have additional comments and/or request additional clarifications. ✓ In the Stantec Initial Completeness Review, question 4 related consideration of sediment transport impacts on hydrology and hydraulics. WCE has provided a response related to design assumptions and the pending O&M Plan. We concur with that approach and consider this question resolved. 5 REVIEW OF AUGUST 20, 2018 WCE RESPONSES TO CITY COMMENTS WCE provided responses to City of Spokane Valley Comments on August 20, 2018, on "Painted Hills Floodplain Review #2" provided by the City on January 4, 2017. Stantec has reviewed each request and response against the material included in the March 8, 2019 WCE Painted Hills Flood Control package. 5.1 GENERAL 1. City: Prior to construction permit release, the following needs to be accomplished: a. Copy of CLOMR from FEMA b. Plan approval WCE Response: We acknowledge that the items listed in a. through b. need to be accomplished for construction permit release. ✓ As these items will follow submittal of the CLOMR Application, there is no follow-up needed at this time. 2. City: Prior to construction acceptance, the following needs to be accomplished : a. Copies of the Department of Ecology (DOE) drywell registrations for all new drywells (submitted with construction certification) b. Record drawings showing as-built condition c. Revisions to HEC-RAS model and reassessment of the free board if construction has altered the channels from that depicted in the model d. Letter from design engineers certifying project constructed according to approved plans and specifications e. Levee certifications (44 CFR 65.10 (e)) f. Construction Certification Package WCE Response: We acknowledge that the items listed in a. through f. need to be accomplished for construction acceptance. ✓ As these items will follow construction, there is no follow-up needed at this time. August 1, 2019 Henry Allen, PE Page 16 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology/ Hydraulics Detailed Review 5.2 FLOOD CONTROL DEVELOPMENT NARRATIVE 3. City: General -please address the requirement for an overflow path for the 100-year storm mentioned in SRSM chapter 2.2.4, paragraph on Infiltration Facilities. WCE Response: We appreciate that the SRSM has this requirement, but as with all standards, requirements are written to cover the majority of situations. There are always exceptions that need to be looked at differently which this site falls into. Since our site is the regional low point designated as compensatory storage, with any possible overflow route blocked by prior development, a requirement for an overflow route is setting us up for failure. The facilities in this submittal are for the relocation of the compensatory storage of floodwaters. Stormwater overflow disposal will be addressed with submittal of plans for each specific subdivision. ✓ The project proponents have provided hydraulic calculations and supporting geotechnical data showing that the proposed improvements for stormwater overflow management include capacity sufficient to convey and infiltrate not only the 10-year design storm event as required in SRSM chapter 2.2.4, paragraph on Infiltration Facilities, but also the 100-year storm volume to drywells and the underlying voids in Spokane Valley gravel. As a result, Stantec concludes the current submittal shows conformance with SRSM chapter 2.2.4, paragraph on Infiltration Facilities. 4. City: Background a. Page 1 paragraph 1-change "when no flood events occurred" to "when no significant flood events occurred". WCE Response: Paragraph revised to include "significant." ✓ The City's request has been adequately addressed. b. Page 2 -since 40th is an east-west oriented street should references to "east of 40th Avenue" be changed to "north (or south) of 40th Avenue"? WCE Response: The portion of 40th Ave adjacent to Storage Area 6 runs northwest to southeast so we have revised the reference to "northeast of. ✓ The City's request has been adequately addressed. c. Change references to "Spokane Rathdrum" aquifer to "Spokane Valley Rathdrum Prairie" aquifer. WCE Response: Aquifer references have been revised . ✓ The City's request has been addressed. 5. Main Flow Across Thorpe Road a. Proposed Design August 1, 2019 Henry Allen, PE Page 17 of 76 Reference: City of Spokane Valley-Painted Hills Development CLOMR, Ordinance, & Hydrology / Hydraulics Detalled Review i. Box Culvert/Open Channel -the text refers to 2-10" culverts but our records say that they are 18". Please check pipe size. WCE Response: We have checked the culverts in the field and there are 3-15" CMP culverts. Text revised. ✓ Based on WCE's statement and a review of the text, the City's comment has been addressed. Noted that there are four 18" culverts under Madison Road. ii. Pipe Mainline -text mentions that along Madison are manholes with sumps but, per WSDOT details, these structures are called catch basins. Please revise. WCE Response: Manhole has been revised to WSDOT Type II catch basin . ✓ Based on WCE's statement and a review of the text, the City's comment has been addressed. iii. Gravel Gallery System - 1. Paragraph 1-please include the design outflow rates of the drywells and the pipe crosses (may need to provide cal cs). WCE Response: The outflow rate of 162.64 cfs has been documented with the new gallery design. These calculations are provided in the flood control narrative appendix. ✓ Based on WCE's statement and a review of the text and additional documentation, the City's comment has been addressed. 2. Paragraph 2 -The design flow of 64 cfs was at Thorpe, please revise the design flow to what it is at the gravel gallery system. WCE Response: The design flow rate for storage area 1 has been revised to 118 cfs as documented in the flood control narrative. ✓ The design flow rate at Thorpe is now shown to be 91 cfs in both the text and the supporting appendix material. As discussed in more detail in Section 3, the technical review portion of this letter regarding hydrologic calculations, the hydraulic capacity of the new box culvert under Thorpe Road is to be 216 cfs. iv. Infiltration Rate - l. Paragraph 1-why is this paragraph included in that TP-29 is at the south end of the site by Thorpe whereas the gravel galleries are at the north end? WCE Response: The paragraph has been deleted. ✓ Based on WCE's response the City's comment has been addressed. August 1, 2019 Henry Allen, PE Page 18 of 76 Reference: City of Spokane Valley-Painted Hills Development CLOMR, Ordinance, & Hydrology / Hydraulics Detailed Review 2. Paragraph 2 -please show how the 1.8 x 10-3 cfs/sf design flow rate was derived. WCE Response: See IPEC addendum report dated 8-22-17. ✓ Based on WCE's response and a review of the referenced supporting document, the City 's comment has been addressed. 6. Secondary Flow Across Madison Road a. Paragraph 1 i. Second sentence -mention that the flow from the most northerly culvert ends up going into culvert at 30+42. WCE Response: Sentence revised to state flows goes to the south. ✓ Based on WCE's response and a review of the text, the City's comment has been addressed. ii. Third sentence -check that the culvert stations listed match those in the table below paragraph 3. WCE Response: Stations revised to match table. -+ A review of the table shows that in addition to the culvert stations noted in the text, the table below paragraph 3 includes a culvert at Station 38+98, for which West Consultants provided a 100-year storm flow of 7 cfs. However, this particular culvert's station is not specifically mentioned in the text. One can infer that this is the most northerly culvert referred to in the second sentence of the first paragraph that does not have an outlet on the west side of Madison Road; however, please reference that culvert's station in the text as well as in the table. 7. Attachments a. Provide outflow rate calculations for the HOPE crosses. If the head required to achieve the outflow rate is significant then check this water surface elevation as a downstream condition in the channel and pipe hydraulic calcs. WCE Response: After consultation with the Geotech, the crosses have been eliminated and 12" perforated pipe will be installed the entire length of the gravel gallery. -+ As noted in Section 3 of this review letter, Stantec has reviewed the hydraulic calculations provided by the project proponents and concerned about the reliance on a single drywell test extrapolated to show infiltration capacity for two separate areas. There is concern related to the underlying soil infiltration rate used in the gravel gallery; please see Section 3 of this letter. b. Open channel calcs -the Q may be a little bit more than 64 cfs when the flow from the two pipes at the upstream end of the channel are included. August 1, 2019 Henry Allen, PE Page 19 of76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology / Hydraulics Detalled Review WCE Response: The open Channel has been revised since the last submittal. The revised open channel occurs between the box culvert and headwall of the two -48" concrete pipes. The design flow has been based upon the 103 cfs 100 yr flood assuming that the channel to the south has been breached just before Thorpe Road. The flow from the roadside swales are anticipated to occur prior to the 100 yr flood, as they have a different time of concentration. ✓ Based on WCE's response and a review of the text, the City's comment has been addressed. c. Pipe System calcs - i. Hydraflow is not on FEMA's list of approved software programs. We recommend that before submitting the study you check with FEMA to see if they will accept this software. WCE Response: So noted; Hydraflow calculations are no longer included in the analysis. ✓ A review of the submitted material shows that Hydraflow calculations are still included in the submitted documents; they are, however, supplemented by commentary referencing SRSM guidance and supplemented by a report of an XPSWMM model analysis conducted by Ken Puhn of West Consultants. The report of that analysis includes 100-year return event water surface elevations at several system locations. ii. Include the two-foot-high level spreader at the downstream end of the system. WCE Response: A 1-foot high spreader, has been called out per the design of the hydraulic engineer (West Consultants). ✓ The 1-foot high spreader is consistent with the SWMM output and appears to be a feasible structure based on the design of the settling basin and gravel gallery presented in the PRO plans provided by WCE (sheet C5.30). d. Gravel gallery- i. Confirm source of the infiltration rate. WCE Response: See IPEC addendum report dated 8-22-17. ✓ Based on WCE's response and a review of the submitted material, the City's comment has been addressed. ii. Check totals for the sidewall area and bottom area columns. The gravel gallery calculations have been revised with the change to the design. WCE Response: The gravel gallery calculations have been revised with the change to the design. August 1, 2019 Henry Allen, PE Page 20 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology / Hydraulics Detailed Review ✓ Based on WCE's response, the revised text, the inclusion of the one-page email report on SWMM modeling, and the annotations in the Hydraflow output, the City's comment has been addressed. e. Bio-filtration swale design -the Manning's n of 0.2 is for shallow flow conditions. What depth does King County consider to be "shallow"? The depth calculated in the analysis is over 4 feet. Use a Manning's n applicable to a 4-foot flow depth. WCE Response: The Manning's n-value has been revised per the Open Channel Hydraulics book by Ven te Chow, specifically Curves for A table on Page 182. Please see the appendix of the Flood Control narrative for a copy of the referenced material. ✓ A review of the "Bio-filtration Swale Design" spreadsheet printouts as well as the appended reference material from Chow shows reasonably conservative values of manning's n have been used. 5.3 BIOLOGICAL EVALUATION 8. Section 4.3, paragraph 1-can a vegetative cover be greater than 100% (top of page 9}? WCE Response: See Biology Soil and Water, Inc., letter dated June 8, 2017. ~ We have been unable to locate the referenced letter in the submitted material. 9. Section 5.3, paragraph 2 -confirm that the items mentioned (work in channel only when dry, BMP's, spill protocols, minimal peripheral impacts, construction fences) are adequately provided in the construction documents. WCE Response: Notes have been added to plans covering these items. ✓ Construction documents now have SWPPP/ESCP documents covering the gravel gallery and Triangle Pond areas that adequately address the City's comment. 10. Section 5.4 -confirm that the items mentioned (BM P's, FEMA specifications) are adequately provided in the construction documents. WCE Response: Notes have been added to plans covering these items. ✓ Construction documents now have BMPs and show buffer areas consistent with Section 5.4; the City's comment has been adequately addressed. 11. Section 6.2, page 26 -because the levees at the small bridges need to be raised, more than 200' of levee needs to be raised. WCE Response: See Biology Soil and Water, Inc., letter dated June 8, 2017. August 1, 2019 Henry Allen, PE Page 21 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology / Hydraulics Detailed Review • We have been unable to locate the referenced letter in the submitted material. However, the Biological Evaluation format and content appear to be different from what the City commented on and in-line with the infiltrative approach rather than levee enhancement. 12. Section 6.7, paragraph 1, all of the 1% flood is being infiltrated. WCE Response: See Biology Soil and Water, Inc., letter dated June 8, 2017. • We have been unable to locate the referenced letter in the submitted material. However, the Biological Evaluation format and content appear to be different from what the City commented on and in-line with the infiltrative approach rather than levee enhancement. 5.4 OPERATIONS AND MAINTENANCE PLAN 13. General: a. This manual needs to be incorporated into the overall O&M Manual for the whole site. WCE Response: Noted. This manual will be incorporated into an overall O&M Manual at the time of its development. ✓ Given the timing of the response relative to development of a Draft EIS, this response adequately addresses the City's comment. b. Include the levee O&M manual from the Geotech Levee Evaluation and Certification report as an appendix. WCE Response: As the City of Spokane Valley has formally rejected the Levee design, all levee design and documentation has been removed. ✓ The response adequately addresses the City's comment. c. Per CFR 65.6{a)(12) mention that the City Manager or designee will be the community official responsible for assuring maintenance activities are accomplished. WCE Response: Responsible official statement has been added on page 1. • The available copy of the O&M Plan, page 1, does not reference the City Manager or designee as the community official responsible for assuring maintenance activities are accomplished. The referenced regulation is 44 CFR 65.6(a)(12), " ... and the title of the local community official who will be responsible for assuring that the maintenance activities are accomplished." Under this federal regulation and City ordinance 21.30.070.D.7.b, the City may require the project proponents and/or their successors fund a professionally-managed maintenance organization to maintain the flood protection facilities. August 1, 2019 Henry Allen, PE Page 22 of 76 Reference: 14. Page 1: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology/ Hydraulics Detailed Review a. Top- i. Spell out what a PRO is. WCE Response: Abbreviations section has been added on page 1. -+ The available copy of the O&M Plan, page 1, does not include a list of abbreviations. iii. State the party who is responsible for O&M until the HOA is formed. WCE Response: Responsible party section has been revised to add Black Reality as the responsible party until the HOA is formed. -+ The available copy of the O&M Plan does not include Black Realty as the responsible party until the HOA is formed. b. Middle, bullet list -add bullet stating HOA is responsible for: Providing annual report each October to Spokane Valley Public Works describing the general status of sinking fund account and also specific inspections, findings and maintenance performed. WCE Response: Bullet items have been added with regards to reporting. -+ The available copy of the O&M Plan does not include the requested bullet items. c. Last paragraph before next section (1.00) -Change to say: The parties mentioned above are primarily responsible for all operations and maintenance of ... WCE Response: Paragraph has been revised to refer to the parties mentioned above. -+ The available copy of the O&M Plan does not include the requested change to the last paragraph. 15. Section 2.00, Drainage Facilities (page 2), paragraph 1 a. Second line -remove "possibly" and "that has historically flowed into the property and" WCE Response: Paragraph has been revised per the comment. -+ The available copy of the O&M Plan does not include the requested changes to the second line of paragraph 1. b. Provide FEMA panel number and effective date. WCE Response: FEMA panel number and effective date have been added. Mainline manhole callout has been revised to WSDOT catch basins. August1,2019 Henry Allen, PE Page 23 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology / Hydraulics Detalled Review -+ The available copy of the O&M Plan does not include the requested additions to Section 2.00. 16. 3.00 Maintenance Requirements and Schedules: a. Right after this section heading include: All inspections and repairs are to be performed by or directly overseen by a qualified professional per this schedule and following major events. Maintenance tasks are to be performed soon after the need is identified and before facility is to perform unless otherwise agreed to by the City. Repairs or replacements are to be completed immediately upon their identification unless otherwise agreed to by the City. Only qualified individuals may enter confined spaces. WCE Response: The above paragraph has been added. -+ The available copy of the O&M Plan does not include the requested addition to Section 3.00. b. First paragraph, last line -change "recommended" to "minimum required" WCE Response: Recommended has been revised to "minimum required." Box Culvert. A table has been added identifying location and agency having jurisdiction. -+ The available copy of the O&M Plan does not include the requested addition to the last line of the first paragraph of Section 3.00. c. Chester Creek and Levee - i. Reference the levee O&M manual from the Geotech Levee Evaluation and Certification and include in the appendix. WCE Response: Reference to the O&M manual has been added to this section and the manual added as Appendix B. -+ The available copy of the O&M Plan does not include the requested additional reference or the addition of an Appendix B that includes the levee O&M manual. ii. Paragraph 1 1. 3rd sentence -add to the end: " ... of the creek and along the north side of Dishman- Mica to Wilbur Road." WCE Response: This sentence has been revised to include additional language. -+ The available copy of the O&M Plan does not include the requested revision to the third sentence of the first paragraph. 2. 4th sentence, revise to say: " ... maintained to ensure flood carrying capacity is maintained and flood flows are .. " August 1, 2019 Henry Allen, PE Page 24 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology / Hydraulics Detailed Review WCE Response: This sentence has been revised to include additional language. + The available copy of the O&M Plan does not include the requested revision to the fourth sentence of the first paragraph. 3. Last sentence, revise to say: "Maintenance of the channel and levee and obtaining permits to perform the maintenance shall be ... " WCE Response: This sentence has been revised to include additional language. + The available copy of the O&M Plan does not include the requested revision to the last sentence of the first paragraph. iii. Paragraph 2, Maintenance Items - 1. 1st bullet -Geotech O&M says grass should be 3" high or taller. Include that grass should not be taller than 12" (per the Biological Evaluation) WCE Response: This sentence has been revised to include additional language. + The available copy of the O&M Plan does not include the requested revision to the first bullet of the second paragraph. 2. 3rd bullet -at end include that only native grasses are to be on the levee. WCE Response: A sentence has been added to allow only native grasses. + The available copy of the O&M Plan does not include the requested additional sentence under the third bullet of the second paragraph. 3. 5th bullet -after this bullet add the following bullet: " Filling out the levee checklist and include it in the annual report to the City. WCE Response: This sentence has been added. + The available copy of the O&M Plan does not include the requested additional bullet and sentence under the fifth bullet of the second paragraph. d. Concrete Channel, first bullet -add to the end of the sentence:" ... and repair or replace damaged portions." WCE Response: This sentence has been revised to include additional language. Pipe lengths updated to current plan under Storm Drain Mainline section. + The available copy of the O&M Plan does not include the requested addition to the first bullet under Concrete Channel. e. Manholes and Catch Basins August1,2019 Henry Allen, PE Page 25 of 76 Reference: City of Spokane Valley-Painted Hills Development CLOMR, Ordinance, & Hydrology / Hydraulics Detailed Review i. 1st sentence -revise to say" ... mainline pipe system has catch basins at pipe junctions and ... " WCE Response: Sentence has been revised to replace manholes with WSDOT Type II catch basins and reference to manholes deleted in heading and throughout section. Catch basin "lids" added to annual inspection. Cross Culverts. Reference to manholes revised to WSDOT Type II catch basins and TV inspections revised to three years. ~ The available copy of the O&M Plan does not include the requested revision to the first sentence under Manholes and Catch Basins. f. Bio-infiltration Swale Maintenance - i. Include mowing? WCE Response: The bio-infiltration swale is not to be mowed. ✓ The response has adequately addressed the City's comment. ii. Include removal of accumulated sediments. WCE Response: A sentence has been added for removal of accumulated sediment. ~ The available copy of the O&M Plan does not include the requested addition of a sentence added for removal of accumulated sediments under Bio-infiltration Swale. g. Drywalls/Gravel Gallery Infiltration Field -include that every X years the pipe and crosses are inspected by camera for clogging and debris. WCE Response: A sentence has been added for camera inspection every three years. fencing. Signs have been added to the twice a year visual inspection. ~ The available copy of the O&M Plan does not include the requested addition of a sentence added for camera inspection under Drywells/Gravel Gallery Infiltration Field. 17. 4.00 Sinking Fund WCE Response: Direction has been added to update the fund calculations per contracted costs and to update each time new contracts are obtained. a. Regular O&M costs - August1,2019 Henry Allen, PE Page 26 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology / Hydraulics Detailed Review i. Confirm that the annual quantities represent "A comprehensive visual inspection of the complete flood control drainage facilities should be conducted twice a year." e.g. Drywell cleaning is 2x/year so annual quantity should be 24. WCE Response: A cost has been added to cover two comprehensive system inspections. This removes the inspection element from the maintenance tasks. Therefore, drywell cleaning annually is a quantity of 12. -+ The available copy of the O&M Plan does not include the addition of a cost to cover two comprehensive system inspections each year. ii. Mowing -mention which facilities are to be mowed WCE Response: Mowing description has been revised to include levee embankments. -+ The available copy of the O&M Plan does not include the addition of a description of what mowing is to be done. iii. Debris removal -mention which facilities are to have removal WCE Response: Debris removal description has been revised to include those facilities anticipated to need debris removal. -+ The available copy of the O&M Plan does not include the addition of a description to the debris removal line item. iv. Pipeline TV inspection -mention which facilities are to be TV'd WCE Response: Pipeline TV inspection has been revised to include the facilities to be TV'd. -+ The available copy of the O&M Plan does not include the addition of which facilities are to be TV'd. v. Manhole inspection -are these the Catch Basins on the trunkline along Madison? WCE Response: Catch basin has been added to the manhole inspection description. -+ The available copy of the O&M Plan does not include the change to add catch basin to the manhole inspection description. vi. Include - 1. Levee inspection and maintenance WCE Response: Levee inspection is included in comprehensive system inspection. Levee maintenance is included in the mowing line item. August 1, 2019 Henry Allen, PE Page 27 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology / Hydraulics Detailed Review ✓ Though the available copy of the O&M Plan has not been updated, based on clarifications described above, the City's comment has been adequately addressed. 2. Madison cross-culvert inspection and maintenance. WCE Response: Culverts has been added to debris removal and pipeline inspection descriptions. • The available copy of the O&M Plan does not include the change to add culverts to the debris removal and pipeline inspection descriptions. 3. Swale reseeding and noxious weed removal WCE Response: A line item has been added for swale reseeding and noxious weed removal. • The available copy of the O&M Plan does not include the additional line item for swale reseeding and noxious weed removal. 4. Fencing, access roads, parking pads, signs inspection and maintenance WCE Response: A line item has been added for fencing, access roads, parking pads, signs inspection and maintenance. • The available copy of the O&M Plan does not include the additional line item for fencing, access roads, parking pads, sign inspection and maintenance. 5. Cost to prepare annual report WCE Response: A line item has been added for cost to prepare annual report. A line item has been added at 20% of total annual costs for contingencies to cover unexpected costs. • The available copy of the O&M Plan does not include the additional line item for cost to prepare an annual report, or the 20% contingency line item. b. Replacement Costs - i. in the first line the manholes are catch basins per WSDOT, WCE Response: Table has been revised adding line items to break out each type of manhole, catch basin, etc. • The available copy of the O&M Plan does not include the revision for type of catch basin or manhole under "Replacement Costs". ii. include trunkline along Madison and trash racks August 1, 2019 Henry Allen, PE Page 28 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology/ Hydraulics Detailed Review WCE Response: Table has been revised adding line items to break out each pipe size including trunkline, culverts and infiltration field. A line item has been added for trash racks. A line item has been added for signs. -+ The available copy of the O&M Plan does not include the revision for pipe size differentiation, or the addition of trash rack or sign line items under "Replacement Costs". 5.5 PRELIMINARY GEOTECHNICAL EVALUATION, PHASE 1 18. Analysis and Preliminary Recommendations -paragraph 2 says that soils good for gravel galleries are in the south part of the site. So, the soils in the north part of the site are not good for gravel galleries? WCE Response: No, the first paragraph states that the site soils are suitable for subsurface infiltration. The second paragraph points out that in the southern portion of site where the alluvial soils are deeper, it may be advantageous to use gravel galleries as opposed to drywells. Supplemental geotechnical work including borings and a drywell test at the north end of the site demonstrate that infiltration is feasible. It is important to consider all of the available reports, and geotechnical information. ✓ Based on the above response, the City's comment has been adequately addressed. 5.6 FULL-SCALE DRYWELL TESTING 19. Figure 1-show where the test occurred. WCE Response: See IPEC revised report dated 8-21-17. -+ Figure 3 of the revised report shows the drywell location, but as noted in Section 3 of this comment letter, it is difficult to tell where that map is in relation to the rest of the project site. 5.7 FLOOD CONTROL PLANS 20. Please include the following City project numbers on all plan sheets: a. SUB-2015-0001 (Subdivision) WCE Response: Number has been added to all sheets. ✓ Verified; the City's comment has been adequately addressed. b. EGR-2016-0066 (Engineered Grading Permit) WCE Response: Number has been added to all sheets. ✓ Verified; the City's comment has been adequately addressed. August 1, 2019 Henry Allen, PE Page 29 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology / Hydraulics Detailed Review c. FDP-2016-0007 (Floodplain Development Permit) WCE Response: Number has been added to all sheets. ✓ Verified; the City's comment has been adequately addressed. 21. All ROW dedications and easements shall be recorded prior to the use of the frontage improvements and flood control elements. Dedications for flood control elements need to be recorded prior to LOMR submittal with their file numbers entered on the plans. We have received and reviewed (comments sent December 15, 2016) the following for flood control elements: a. an access easement and a drainage easement for the flood control bioswale and infiltration areas, b. a temporary drainage easement (initially called a temporary construction easement) for the storm drain pipe along Madison Road, and c. a drainage easement along Thorpe Road. WCE Response: As per our discussions, these easements and dedications will be completed following CLOMR review prior to LOMR submittal. ✓ A review of the plans indicates relevant easement boundaries and types are shown throughout the plan set. Given the project status is pre-LOMR, the City's comments have been adequately addressed. City: Please provide draft legal descriptions and exhibits for the following for flood control elements: a. Border Easements along Dishman-Mica that involve a levee, WCE Response: As per our discussions, these easements and dedications will be submitted for review and completed following CLOMR review prior to LOMR submittal. ✓ Given the project status is pre-LOMR, the City's comments have been adequately addressed. b. Slope easements along levee slopes not covered by a border easement, WCE Response: As per our discussions, these easements and dedications will be submitted for review and completed following CLOMR review prior to LOMR submittal. ✓ Given the project status is pre-LOMR, the City's comments have been adequately addressed. c. Access easements along levees that are outside the border easement. August 1, 2019 Henry Allen, PE Page 30 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology/ Hydraulics Detailed Review WCE Response: As per our discussions, these easements and dedications will be submitted for review and completed following CLOMR review prior to LOMR submittal. ✓ Given the project status is pre-LOMR, the City's comments have been adequately addressed. City: Please provide draft legal descriptions and exhibits for the following (non-flood control elements): a. ROW dedication at the NE corner of Thorpe and Dishman-Mica, WCE Response: As per our discussions, these easements and dedications will be submitted for review and completed following CLOMR review prior to LOMR submittal. ✓ Given the project status is pre-LOMR, the City's comments have been adequately addressed. b. ROW dedication at the NW corner of Thorpe and Madison, WCE Response: As per our discussions, these easements and dedications will be submitted for review and completed following CLOMR review prior to LOMR submittal ✓ Given the project status is pre-LOMR, the City's comments have been adequately addressed. c. ROW dedication to the BCR's of Roads A through D on Madison, WCE Response: As per our discussions, these easements and dedications will be submitted for review and completed following CLOMR review prior to LOMR submittal ✓ Given the project status is pre-LOMR, the City's comments have been adequately addressed. d. ROW dedication to the BCR's of Road E and the multi-family driveway approach on Dishman- Mica, WCE Response: As per our discussions, these easements and dedications will be submitted for review and completed following CLOMR review prior to LOMR submittal. ✓ Given the project status is pre-LOMR, the City's comments have been adequately addressed. e. Border Easements along Dishman-Mica that don't involve a levee, WCE Response: As a levee is no longer part of the flood control design the need for an additional easement is being assessed. As per our discussions, these easements and dedications will be submitted for review and completed following CLOMR review prior to LOMR submittal. ✓ Given the project status is pre-LOMR, the City's comments have been adequately addressed. August 1, 2019 Henry Allen, PE Page 31 of 76 Reference: City of Spokane Valley-Painted Hills Development CLOMR, Ordinance, & Hydrology / Hydraulics Detailed Review f. Border Easements along Thorpe and Madison, WCE Response: As a levee is no longer part of the flood control design the need for an additional easement is being assessed. As per our discussions, these easements and dedications will be submitted for review and completed following CLOMR review prior to LOMR submittal. ✓ Given the project status is pre-LOMR, the City's comments have been adequately addressed. g. Access easement for Dishman-Mica sidewalk that meanders into site. WCE Response: As per our discussions, these easements and dedications will be submitted for review and completed following CLOMR review prior to LOMR submittal. ✓ Given the project status is pre-LOMR, the City's comments have been adequately addressed. 22. Based on the street classification and project soil types, a pavement design shall be required for Dishman-Mica, Thorpe and Madison per SVSS Chapter 8. WCE Response: A pavement design has been provided in IPEC report dated June 26, 2017. See flood control narrative for referenced report. • The referenced report has been reviewed and includes an industry standard approach to pavement design recommendations. The PRO plans have been reviewed and pavement sections are included on sheet P2.0 of that plan set. However, the plan sheet sections do not completely agree with IPEC's recommended sections for aggregate base thickness, though the thickness design parameters are within the range of standard sections for Spokane Valley. 23. Please submit a striping and signage plan for Dishman-Mica Road. Coordinate with the Traffic Impact Analysis for required left turn lanes and two-way left turn lanes. Show how the two-way left turn lane will taper at the Chester Creek crossing where the pavement section narrows. WCE Response: Signage and striping plans for Dishman-Mica Road, Thorpe Road, and Madison Road have been provided on sheets CIO.O, CI0.1,& CI0.2 ✓ The referenced drawings sheets are included in the plan set and include the requested two-way left turn lane and taper on Dishman-Mica Road. 24. Please provide a Design Deviation Request for the following: a. Two driveway approaches for Dishman-Mica Road (SVSS 7.8.2.b) • No response has been received from WCE regarding this request, or a response has not been forwarded for review. August 1, 2019 Henry Allen, PE Page 32 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology/ Hydraulics Detailed Review 25. For proposed utility adjustments and relocations, the applicanUengineer is required to contact each utility purveyor impacted by the required utility relocations and: - a. Discuss with the purveyor the proposed work including relocations and adjustments as well as the costs for these activities, WCE Response: So Noted, with the revised plans coordination with the water and sewer purveyors will be completed. -+ Submitted plans include water and sewer utility connections, which evidence at least some plan coordination with the utility providers. Costs have not been included with the materials available for review. b. Obtain from the purveyor a written statement that they acknowledge and concur with or have alternatives for the needed work, and WCE Response: So noted. -+ Written statements from utility purveyors were not included in the materials available for review. c. Forward a copy of the statement to Spokane Valley Development Engineering. Receipt of statements will be required prior to civil plan approval. WCE Response: So Noted. -+ Written statements from utility purveyors were not included in the materials available for review. d. Show the location of any relocated utilities. WCE Response: Relocated utilities are shown on the Water and Sewer plans. ✓ Relocated utilities have been verified to be shown on the street and Water plans. 26. Please submit a drainage report for the roadside swales. Include curb inlet and non-flooded roadway width calculations. WCE Response: A drainage report has been prepared for the roadway frontage. ✓ A drainage report was included and reviewed. The report follows SRSM requirements for analyses and content. No further comments are deemed necessary regarding the report content. 27. Confirm there is maintenance access to all stormwater and levee facilities (SRSM 11.1.6) and provide approaches where accesses connect to a road. August 1, 2019 Henry Allen, PE Page 33 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology / Hydraulics Detailed Review WCE Response: Maintenance access has been provided for storm and flood control facilities. ✓ A review of the provided plans verifies maintenance access has been provided for the storm and flood control facilities. 28. If flood flows varied from those modeled and they ended up exceeding system design, for instance at the infiltration/gravel gallery area, will there be any time for response between the exceedance occurring and properties being inundated? WCE Response: As Flood Events occur over a period of days and weeks there is time to manage the flood control facilities if need be. The proposed flood control facility is designed to handle the 100-year flood event, with additional design capacity as a part of the design safety factor. In addition, a surge protection at the open channel and headwall is included that will take the surge into the lowered park area. This additional storage would eventually be channeled back into the flood system via a catch basin and pipe to the west 48" pipe. For any Flood event beyond the 100-year event the proposed finish floor of the residences and the commercial buildings are graded above the BFE, so any flooding would be maintained in the streets, with minimal incursion into the structures. See Flood Control Narrative for specific design information. ~ Proponents' response is generally consistent with the provided design and calculations, except as noted in comments in Section 3 of this letter. 29. Incorporate into the design the recommendations mentioned in: a. The Biological Evaluation in sections 5.3 (e.g. best management practices, construction fences around minimized work areas, restoration of impacts) and 6.5 (signs). WCE Response: As the Levees are no longer part of the flood control system it is proposed that the implementation of the biological evaluation and management plan be prepared after the completion and survey of the completed fill, otherwise an approved plan would have to be modified once the fill is surveyed. ✓ The Biological Evaluation documents submitted with March 5, 2019 package is organized differently from the comment and WCE's response. It appears that the design has incorporated the key recommendation of the current Biological Evaluation, including: o Buffer widths, o Vegetation for noxious weed control, erosion and sediment control, and habitat enhancement However, wetland buffer notification signs or placement were not noted in the design documents. August 1, 2019 Henry Allen, PE Page 34 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology / Hydraulics Detailed Review b. O&M Manual, Drainage Facilities section (signs). WCE Response: Signs are proposed to be placed upon fences. ✓ So noted. Drainage facility signs were found in one location in the plan set. Sheet C5.30 contains a callout for placement of sign. However, precise location is not identified. Sheet C0.O 30. In the 'Dev. Const. lnsp.' contact information section, please revise the phone number to 599-6306 and the contact name to Ken Van Dyk. In the 'Roadways' section, please change the phone number to 720- 5008 and remove the contact name. Applies to Sheet C9.0 as well. WCE Response: Contacts have been revised on sheets C0.0 and C9.0. ✓ Plan review verifies that this has been done. 31. Make sure all sheet titles match the titles in the Sheet Index. WCE Response: Sheet titles and/or sheet index have been revised to match. ~ Sheet index needs to be updated to include C7.X Water Utility plans and C8.X Sewer Utility plans. In addition, plan sheet references were changed in this submittal and many callouts were not updated with new numbering and sheet names. Sheet C0.1(General Notes) 32. SV Note #6 -change should to shall. WCE Response: Note revised to read "shall.'' ✓ Spokane Valley General Construction note #6 now reads, "shall". Sheet C0.2 (Dishman-Mica Road Sections) 33. For the Dishman-Mica Road Widening Calculations: a. Provide a column that depicts the existing super-elevated cross-slopes and adjust the proposed cross-slopes to match. The minimum proposed cross-slopes shall be 2%, WCE Response: The widening calculations have been revised and the cross slope has been matched. August 1, 2019 Henry Allen, PE Page 35 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology/ Hydraulics Detailed Review ✓ Review of Sheet C0.2 confirms WCE's response. However, the minimum proposed cross slopes are less than 2% from Station 27+00 through 32+00, then Stations 32+85.69 and 33+00. However, these variances do match the existing cross slopes as requested. b. Check the Proposed Curb Elevations. WCE Response: The proposed curb elevations are based upon the varying cross slope and have been checked accordingly. ✓ A spot check of curb elevations corroborates WCE's response and appears to match the plans .. 34. For Sections 1-3, please: a. Label the street centerline, WCE Response: The centerline has been labeled. ✓ A check of the sections verifies use of the standard centerline symbol. b. Revise the cross-slope of the pavement widening to match the existing super-elevated cross-slopes and provide the range of cross-slopes, WCE Response: The cross slopes have been revised to match the existing cross slope. ✓ A plan check verifies that the design cross slopes match the existing cross slopes. c. Verify the pavement section with a pavement design. WCE Response: See IPEC Geotechnical Evaluation dated June 26, 2017. + The pavement sections generally follow the guidance of the referenced report; however, in this case on Dishman-Mica the design aggregate base is 6-inches rather than the IPEC- recommended 12-inches in depth. See comment response 22. d. Specify PG 70-28 for the HMA pavement. WCE Response: The HMA pavement type has been added. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 35. For Section t please: a. Revise the planter strip width to 7' per SVSS 7.5.10. WCE Response: The planter strip width has been revised. August1,2019 Henry Allen, PE Page 36 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology/ Hydraulics Detailed Review ✓ A review of the plans verifies that the City's comment has been adequately addressed. b. Extend the border easement to the toe of the slope or provide a separate slope easement, WCE Response: The border easement has been extended to encompass the toe of slope. ✓ A review of the plans verifies that the City's comment has been adequately addressed. c. Reference SVSS Standard Plan R-103 for the 6' sidewalk. WCE Response: The Standard Plan has been referenced. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 36. For Section 2, please: a. Listthe range of pavement widths, WCE Response: The range of pavement widths does not vary within the cross section. The pavement width does change at the bridge crossing and becomes 19' wide. ✓ A review of the plans verifies that the City's comment has been adequately addressed. b. Remove the 1 O' border easement. WCE Response: Border easement has been revised to 15' ✓ A review of the plans verifies that the City's comment has been adequately addressed in a manner consistent with other comments. 37. For Section 3, please: a. Verify the need for the roadside swale, WCE Response: The roadside swale along Dishman Mica Road has been reduced in size, and will capture any project flow and receive plowed snow from the road surface. ✓ The City's comment has been adequately addressed in a manner consistent with other comments and responses. b. Extend the border easement to the toe of the levee slope or provide a separate slope easement, WCE Response: The border easement has been revised. ✓ A review of the plans verifies that the City's comment has been adequately addressed. c. List the range of pavement widths August 1, 2019 Henry Allen, PE Page 37 of 76 Reference: City of Spokane Valley-Painted Hills Development CLOMR, Ordinance, & Hydrology / Hydraulics Detailed Review WCE Response: The range of pavement widths are shown. See previous response. ✓ A review of the plans indicates the range of pavements widths applicable to Section 3 is 19-feet to 22 feet; both values are shown on the section, with the 19-foot value included in "Pavement Width is 19' at Chester Creek Crossing". In that sense the City's comment has been addressed. d. Adjust the 34' and 64' dimension strings to end at the ROW. WCE Response: Dimension strings have been adjusted. ✓ A review of the plans verifies that the City's comment has been adequately addressed. e. For the 8' asphalt path: locate the construction line location and specify the pavement section and a cross-slope. If maintenance vehicles will utilize the asphalt path, verify the width and pavement section. WCE Response: The asphalt path width and cross section have been revised to a 10-foot path with 1-foot shoulders. An alignment has been added and will act as the construction line. -+ From the revised plans, the WCE response is accurate. However, the asphalt path pavement section is not shown. Sheet CO. 3 (Thorpe and Madison Road Sections) 38. For Section 4, please: a. Provide applicable stationing for this section. WCE Response: Stationing has been added to the section. ✓ A review of the plans verifies that the City's comment has been adequately addressed. b. Reference SVSS Standard Plans R-102 for the curb and gutter and R-103 for the sidewalk, WCE Response: The standard plans have been referenced. ✓ A review of the plans verifies that the City's comment has been adequately addressed. c. Verify the pavement section with a pavement design. WCE Response: See IPEC Geotechnical Evaluation dated June 26, 2017. -+ The pavement sections generally follow the guidance of the referenced report; however, in this case on Thorpe the design aggregate base is 6-inches rather than the IPEC-recommended 12- inches in depth. See comment response 22. 39. Provide a separate cross section of Thorpe Road that includes the concrete channel. August 1, 2019 Henry Allen, PE Page 38 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology/ Hydraullcs Detailed Review WCE Response: For clarity and simplification, the cross section of Thorpe Road and the channel/box culvert has been provided on Sheet C5.1. A note has been added to this affect. ✓ A review of the plans indicates the response is generally correct. However, the note on plan sheet C0.3 states, "See Sheet C5.2 for details"; when looking for that sheet, the detail sheet with the referenced detail is actually numbered "C5.1 0" in its title block. The sheet index on C0.0 is consistent with the "C5.1 0" designation. 40. For Section 5, please: a. Provide applicable stationing for this section. WCE Response: Stationing has been added to the section. ✓ A review of the plans verifies that the City's comment has been adequately addressed. b. Provide a pavement and gravel section for the meandering path, note that this path will be used by a vactor truck to clean out drainage facilities, WCE Response: A pavement section has been provided. ✓ A review of the plans verifies that the City's comment has been adequately addressed. c. Label the range of cross-slopes for the widening per the widening calculations, WCE Response: The slope has been revised to be 3.00%. ✓ A review of the plans verifies that the City's comment has been adequately addressed. d. Adjust the border easement width to account for the meandering path. WCE Response: The boarder easement has been revised to the width of the proposed tract. ✓ A review of the plans verifies that the City's comment has been adequately addressed. e. Label the varying swale widths to account for the meandering path. WCE Response: The swale width is uniform, the cross section has been revised to reflect the uniform width with a note listing the range of widths from swale to path. ✓ A review of the plans verifies that the City's comment has been adequately addressed. f. Label the dimension from the ROW to the centerline of the 60" storm pipe. WCE Response: This dimension has been added to the 2-48" pipes. -+ A dimension line has been added from the ROW line to somewhere on the more easterly 48-inch pipe. However, from the detail as drafted it is unclear where that dimension is supposed to August 1, 2019 Henry Allen, PE Page 39 of 76 Reference: City of Spokane Valley-Painted Hills Development CLOMR, Ordinance, & Hydrology / Hydraulics Detalled Review intersect the pipe. g. Verify the pavement section with a pavement design. WCE Response: See IPEC Geotechnical Evaluation dated June 26, 2017. ✓ A review of the plans and the referenced report verifies that the City's comment has been adequately addressed; in this case the IPEC report and section call-out agree. See comment response 22 for additional detail. 41. For Sections 4 and 5 and the roadside swales, include the following or provide a separate swale section: a. 3:1 maximum side slopes, WCE Response: The slope has been labeled on a typical section. ✓ A review of the plans and the referenced report verifies that the City's comment has been adequately addressed. b. 12" treatment soil zone. WCE Response: The treatment soil has been called out on a typical section. ✓ A review of the plans verifies that the City's comment has been adequately addressed. c. If the following treatment soils are installed, the City of Spokane Valley does not require soil testing per SRSM: "For swales and ponds, the top 12 inches of soil shall consist of a thoroughly blended mix of 50% compost with 50% native soils. " WCE Response: So noted. A note has been added to the typical swale section. ✓ A review of the plans verifies that the City's comment has been adequately addressed. d. Note requiring swale bottoms and side slops shall be lined with sod/hydroseed. WCE Response: A note for hydro seeding has been added with a seeding note on Sheet C4.1. -+ The note for hydro seeding is on C0.3. No Sheet C.4.1 was in the plan set. e. Typical bottom dimensions and depth, WCE Response: A typical cross section has been provided with the elements of items a through f. ✓ A review of the plans verifies that the City's comment has been adequately addressed. August1,2019 Henry Allen, PE Page 40 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology / Hydraulics Detailed Review f. Show a typical drywell or catch basin section with the 6" treatment depth and minimum depth from rim to flowline. WCE Response: A typical catch basin has been shown with call outs of 0.5' bottom to rim and 0.8' bottom to flowline. ✓ A review of the plans verifies that the City's comment has been adequately addressed. Sheet C1 .3 (Site Element Plan) 42. Coordinate the 'Madison Rd Easement Plan' section with Sheet C0.3. WCE Response: The plan and section have been coordinated. + The Madison Rd Easement Plan section is similar to the section 5 shown on C0.3, except the dimensions from the ROW line to the east-most pipe are different. 43. Plan view calls out 2-1 O" culverts under Thorpe but our records say that they are 18". Please check the pipe size. WCE Response: We have checked and measured the culverts in the field and there are 3-15" CMP culverts. The text has been revised. ✓ A review of the plans and associated documents verifies that the City's comment has been adequately addressed. Sheets C3.00-C3.23 44. Reference intersection detail sheet at all applicable intersections. WCE Response: The intersection detail sheet was referenced with the centerline-centerline callout in the plan view. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 45. Make sure all proposed and existing ROW and all easements are labelled. a. Where levee is outside the ROW and Border Easements provide access and slope easements. WCE Response: The ROW and easements have been labeled. + A review of the plans indicates there are some sheets on which some easements have not been labeled; otherwise, the review verifies that the City's comment has been addressed. Sheet C3.00 (Dishman-Mica Road P&P) August 1, 2019 Henry Allen, PE Page 41 of76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology / Hydraulics Detailed Review 46. For the sidewalk that extends from Dishman-Mica Road to onsite: a. Provide the station and radius of the curve, WCE Response: A reference is made to see sheet C3.03. Sheet C3.03 has a plan and profile for the sidewalk. ✓ A review of the plans verifies that the City's comment has been adequately addressed. b. Provide a plan view that shows the entire alignment of the onsite sidewalk. WCE Response: Plan view has been added on sheet C3.03. ✓ A review of the plans verifies that the City's comment has been adequately addressed. c. Provide finish grade spot elevations that comply with ADA guidelines and include a cross- slope for drainage. WCE Response: Profile has been added on sheet C3.03. Cross slope callouts have been added on sheet C3.03. ✓ A review of the plans verifies that the City's comment has been adequately addressed. d. Show and label the access easement for all portions of the sidewalk located onsite. WCE Response: Access easement has been added on sheet C3.03. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 47. Please identify the existing hydrant near STA 22+40 and the power pole and telephone pedestal near STA 22+60. Determine if relocations are required. WCE Response: The existing fire hydrant has been called out. There is no relocation necessary. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 48. For the new guardrail it will need to extend farther to the south than indicated on the plan due to the posted speed limit and slopes. The curb and gutter does not provide an adequate barrier in this situation. Verify the required length of the guardrail and the clear zone requirements with AASHTO Roadside Design Guide. WCE Response: New guardrail has been called out two feet behind the curb at the location of the existing guardrail. ✓ A review of the plans verifies that the City's comment has been adequately addressed. August 1, 2019 Henry Allen, PE Page 42 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology / Hydraulics Detailed Review 49. For Construction Note #10, specify the start STA for the guardrail and reference new guardrail only. WCE Response: Stationing for new guardrail has been added. See construction note 9. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 50. For Construction Note #11, specify the start and end stations of the pavement taper. The required taper length shall be calculated per L = ws, where 'w' is the widening width and 's' is the posted speed limit of 45 mph. WCE Response: The pavement taper south of the Dishman-Mica Rd box culvert and at the north end of the property has been calculated by L=WS and the start and end stations have been called out. The taper just north of the Dishman-Mica Rd box culvert has been widened per the meeting on 6/12/17. ✓ A review of the plans verifies that the City's comment has been adequately addressed. However, station callouts do not have offsets, which would help verify calculation. 51. The Traffic Impact Analysis mentions streetlights along Dishman-Mica. Please show the light locations and specify that the lights will be installed with the plat. Specify necessary conduit sleeves to be installed with the frontage improvements. WCE Response: Street lights have been called out at public intersections. -+ In review of the plans, new street light location is not identified at Thorpe Road intersection where an existing light is getting removed. Conduit locations not identified in plans. However, note for Sundown Rd intersection indicates "coordinate final location and power supply with Inland Power". 52. In the profile, adjust the Top of Curb elevations to match the existing super-elevated cross slopes and the revised Road Widening Calculations from Sheet C0.2 WCE Response: The TBC has been revised to match the existing super-elevated cross- slopes. -+ In review of the plans, most elevations are matching Sheet C0.2. However, TBC elevations at Stations 25+00, and 25+50 do not match table. Sheet C3.01 (Dishman~Mica Road P&P) 53. For Construction Note #2, please reference Sheet C0.2. WCE Response: Sheet C0.2 has been referenced in construction note 2. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 54. For Construction Note #3, please reference a 'spill' curb, similar to Sheet C3.00. August1,2019 Henry Allen, PE Page 43 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology / Hydraulics Detailed Review WCE Response: Spill curb is now referenced in construction note 3. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 55. For Construction Note #4, reference the appropriate plan sheet and detail for the asphalt path details. The City does not have specific standards for asphalt pathways. WCE Response: Sheet and detail are now referenced in construction note 4. ✓ A detail is not referenced in note 4. However, pathway section information is provided in note. Therefore, a review of the plans indicates the intent of the City's comment has been adequately addressed. 56. Since the 8' pathway will be driven on, provide adequate turning radii around the approaches. WCE Response: With the removal of the levee the path will no longer be driven upon. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 57. Verify Construction Note #5 for this sheet. WCE Response: Note 5 has been revised to reference a different construction item. ✓ A review of the plans verifies that the City's comment has been adequately addressed. Note 5 is no longer being reference and noted as "Reserved". 58. For the pedestrian ramps at Road 'E', provide sidewalks on each side of the Road 'E' to down to the ramps or provide sidewalks from the top of the levees down to the pedestrian ramps. Short sections of adjacent sidewalk at the ramps will be acceptable. WCE Response: Sidewalks and ramps are now provided at Sundown Road (road E). ✓ A review of the plans verifies that the City's comment has been adequately addressed. 59. Road E -show how stormwater flowing down/along Road E is captured before it gets to Dishman- Mica and is disposed of. WCE Response: Plan has been revised to direct stormwater off Sundown Rd via under Type 2 curb inlets into roadside swales behind the sidewalk/curb. See sheet C3.03 for details. -+ In review of the plans, this does not appear have been addressed. There are no Type 2 curb inlets called out on Sundown and details are not provided on sheet C3.03. In fact, although not called out anywhere in the plans, the plan view shows inlets on Dishman-Mica where the spill curb is located (which won't direct flow to the swale). A transition from spill curb to standard curb needs to occur if inlets remain on Dishman-Mica and there are no Type 2 inlets indicated on Sundown. 60. For Construction Note #10 please verify the Standard Plan R-113 reference, as it is intended for adjacent sidewalks. August 1, 2019 Henry Allen, PE Page 44 of 76 Reference: City of Spokane Valley-Painted Hills Development CLOMR, Ordinance, & Hydrology/ Hydraulics Detailed Review WCE Response: Note has been revised to reference Std Plan R-111. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 61. For Construction Note #12, please verify the sheet reference. WCE Response: Note has been revised to reference sheet C4.2. + In review of the plans, note #12 has been changed to "Reserved". Perhaps callout is no longer required as there is no Sheet C4.2 in plan set. 62. For Construction Note #15, specify the start and end stations of the pavement taper. The required taper length shall be calculated per L = ws, where 'w' is the widening width and 's' is the posted speed limit of 45 mph. WCE Response: Taper stations have been added. Per meeting at the City, the taper length has been shortened to provide full width widening at the driveway approach. + In review of the plans, taper occurs on sheet C3.02 and it is unclear what length the taper is supposed to be because offsets are not provided. The calculations show 175', plan view has the taper at 163' based on station callouts, and Note 9 indicates 220.5'. It is unclear which taper length is intended. 63. For the approach at STA 35+25, show the curb returns and provide pedestrian ramps. Provide sidewalks down to the ramps. WCE Response: This is outside the match line and shows on sheet C3.02 ✓ A review of the plans verifies that the City's comment is addressed regarding sheet C3.02. 64. Provide Type Ill barricades per SVSS Standard Plans R-142 at each approach and Road 'E' until they are operational. WCE Response: Construction note 13 added to provide for barricades. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 65. Please provide centerline stations for the driveway approaches at STA 28+75 and 35+25. WCE Response: Centerline stations have been added. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 66. In the profile, adjust the Top of Curb elevations to match the existing super-elevated cross-slopes and the revised Road Widening Calculations from Sheet C0.2. WCE Response: The TBC elevations have been revised to match the super-elevated cross- slopes. August 1, 2019 Henry Allen, PE Page 45 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology/ Hydraullcs Detalled Review -+ In review of the plans, most elevations are matching Sheet C0.2. However, TBC elevation at Station 32+50 does not match table. Sheet C3.02 {Dishman-Mica Road P&P) 67. See all applicable review comments from Sheet C3.01 for this sheet. (53) For Construction Note #2, please reference Sheet C0.2. WCE Response: Sheet C0.2 has been referenced in construction note 2. ✓ A review of the plans verifies that the City's comment has been adequately addressed. (54) For Construction Note #3, please reference a 'spill' curb, similar to Sheet C3.00. WCE Response: Spill curb is now referenced in construction note 3. ✓ A review of the plans verifies that the City's comment has been adequately addressed. (55) For Construction Note #4, reference the appropriate plan sheet and detail for the asphalt path details. The City does not have specific standards for asphalt pathways. WCE Response: Sheet and detail are now referenced in construction note 4. ✓ A detail is not referenced in note 4. However, pathway section information is provided in note. Therefore, a review of the plans indicates the intent of the City's comment has been adequately addressed. (56) Since the 8' pathway will be driven on, provide adequate turning radii around the approaches. WCE Response: With the removal of the levee the path will no longer be driven upon. ✓ A review of the plans verifies that the City's comment has been adequately addressed if levee has been removed. (57) Verify Construction Note #5 for this sheet. WCE Response: Note 5 has been revised to reference a different construction item. ✓ A review of the plans verifies that the City's comment has been adequately addressed. Note 5 is no longer being reference and noted as "Reserved" (63) For the approach at STA 35+25, show the curb returns and provide pedestrian ramps. Provide sidewalks down to the ramps. WCE Response: The plan has been revised. August 1, 2019 Henry Allen, PE Page 46 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology/ Hydraulics Detalled Review ✓ A review of the plans verifies that the City's comment has been adequately addressed. A commercial driveway per R-111 is now being proposed. (64) Provide Type Ill barricades per SVSS Standard Plans R-142 at each approach and Road 'E' until they are operational. WCE Response: None given. (addressed in comment 73) ✓ A review of the plans verifies that the City's comment has been adequately addressed. Barricades are provided in Note 11. (65) Please provide centerline stations for the driveway approaches at STA 28+ 75 and 35+25. WCE Response: Centerline stations have been added. ✓ A review of the plans verifies that the City's comment has been adequately addressed. (66) In the profile, adjust the Top of Curb elevations to match the existing super-elevated cross-slopes and the revised Road Widening Calculations from Sheet C0.2. WCE Response: The TBC elevations have been revised to match the super-elevated cross- slopes. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 68. Please remove the extraneous hextag #1 near STA 39+75. WCE Response: The Hex tag has been removed. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 69. For levee and 8' path to be installed on church property from STA 35+82 to 39+80: a. Please provide evidence of granted permission from the church to build on their property. WCE Response: With the removal of the Levee from the flood control system the levee on the church property has also been removed ✓ A review of the plans verifies that the City's comment has been adequately addressed. b. Provide access, slope and construction easements. WCE Response: A slope and construction easement has been shown. See sheet C4.0. ~ In review of the plans, a 36' border/levee access and maintenance easement is indicated on the sheet, it is unclear if this is still the case based on comment #69. No easements are indicated on Sheet C4.0. Sheet C5.0 has a note indicating "Temporary access & drainage easement to be De•:fgn with corn1n1nily in rnird August1,2019 Henry Allen, PE Page 47 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology/ Hydraulics Detailed Review altered at final plat". Temporary access, slope and construction easements should be established prior to construction, not at final plat. 70. For Construction Note #9, specify the start and end stations of the pavement taper. The required taper length shall be calculated per L = ws, where 'w' is the widening width and 's' is the posted speed limit of 45 mph. WCE Response: Stations have been added. -+ In review of the plans, it is unclear what length the taper is supposed to be because offsets are not provided. The calculations show 175', plan view has the taper at 163' based on station callouts, and Note 9 indicates 220.5'. It is unclear which taper length is intended or required. 71. Any relocated utilities shall be located outside of the clear zone. WCE Response: Construction note 7 required relocations to be outside the clear zone. Additional utility items have had hextags added. ✓ In review of the plans, there are no hextags added to plan view. However, the note covers the possibility and directs contractor to coordinate with the appropriate agency prior to relocation. 72. For Construction Note #10 please verify the Standard Plan R-113 reference, as it is intended for adjacent sidewalks. WCE Response: Note has been revised to reference Std Plan R-111. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 73. Provide Type Ill barricade per SVSS Standard Plans R-142 at the approach until it is operational. WCE Response: Construction note 11 added to provide for barricades. ✓ A review of the plans verifies that the City's comment has been adequately addressed. Sheet C3.10 (Thorpe Road P&P) 74. In the Left Top of Curb Profile, show all text for the vertical curves. WCE Response: Profile adjusted to show all text. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 75. In the profiles, the minimum 'k' value for sag vertical curves is 50 per SVSS Table 7.1. WCE Response: As requested in the 6/12/17 meeting the difference in elevation between a VC with K=50 and a VC with a K=40 has been calculated. The difference is 0.59'. Due to the lack of room to lengthen the existing VC the grades had to be changed to calculate the VC with K=50. De,,,r v/th co,nrnureily in 1)1ind August 1, 2019 Henry Allen, PE Page 48 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology/ Hydraulics Detailed Review ✓ A review of the plans verifies that the City's comment has been addressed based on information provided. However, WCE response intended to convey that the grades had to be changed to calculate the VC with K=40 (not 50). 76. In the profiles, the minimum 'k' value for crest vertical curves is 30 per SVSS Table 7.1. WCE Response: The length of room provided in this area of Thorpe allowed for the VC to be lengthened and meet the K value of 30. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 77. For Construction Note #2, please reference Detail 4 on Sheet C0.3. WCE Response: Reference revised to Detail 4 on sheet C0.3. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 78. For Construction Note #6, reference the roadside swale section in the detail sheets, in addition to S-130. WCE Response: Reference has been revised to Detail A on sheet C0.3 and Std Plan S-130. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 79. Label existing sidewalk to remain between STA's 15+00 and 17+00. WCE Response: Label with stations has been added. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 80. Construction Note #7 at ST A 11 +53. 78 should reference a driveway approach with a separated sidewalk. See Standard Plans R-110 through R-112. WCE Response: Construction note 19 added to reference Std Plan R-110. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 81. Identify hextag #10 at each end of the existing sidewalk near STA 15+00 and 17+00. WCE Response: Hextag 10 added with stationing. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 82. For the change in direction of the sidewalks near ST A's 13+90, 14+75, and 16+75, please limit the maximum angle of change to 30 degrees. WCE Response: The angle has been revised to 30 degrees. ✓ A review of the plans verifies that the City's comment has been adequately addressed. August 1, 2019 Henry Allen, PE Page 49 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology / Hydraulics Detalled Review 83. For Construction Note #17, please locate the drywell near the low point. Maintain 5' of horizontal clearance from the nearest curb inlet. Verify that the drywell rim will be 0.25'minimum below the adjacent flowline elevation. WCE Response: The Catch Basin has been moved to the lowest pond level. ✓ Profile shows Top of Curb LT at Sta 12+93.40. Catch basin callout is located at Sta. 12+78.5, so this is not the low point of the swale. However, curb inlet is shown near 12+91 so flow gets to the drywell and swale will function as designed, maintaining minimum 5' of clearance from nearest inlet. Based on these parameters, the intent of the City's comment has been addressed. 84. Please provide stationing for all curb inlets. Limit maximum spacing of curb inlets to 100', or less depending on curb inlet calculations. Locate the curb inlets to maximize swale treatment. WCE Response: Curb inlet location table added to sheet C3.11 per note on this sheet. Spacing has been revised per 100 ft maximum and/or to maximize treatment. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 85. Roadside swales are considered flat for volume calculations where the swale bottom slope is 1 % or less. Address all roadside swales where the street grades exceed 1 %. WCE Response: Check dams have been added where slope exceeds 1 %. See sheet C0.3 for check dam detail. ✓ A review of the plans verifies that the City's comment has been adequately addressed. Sheet C3.11 (Thorpe Road P&P) 86. See all applicable review comments from Sheet C3.10 for this sheet. (77) For Construction Note #2, please reference Detail 4 on Sheet C0.3. WCE Response: Reference revised to Detail 4 on sheet C0.3. ✓ A review of the plans verifies that the City's comment has been adequately addressed. (78) For Construction Note #6, reference the roadside swale section in the detail sheets, in addition to S-130. WCE Response: Reference has been revised to Detail A on sheet C0.3 and Std Plan S-130. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 87. Please provide a Construction Note for the 6' wide sidewalk at the box culvert. WCE Response: Construction note 18 added for 6 ft sidewalk ✓ A review of the plans verifies that the City's comment has been adequately addressed. August 1, 2019 Henry Allen, PE Page 50 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology / Hydraulics Detailed Review 88. Drainage easement to be labeled as permanent. WCE Response: Easement label has been revised. ✓ A review of the plans verifies that the intent City's comment has been adequately addressed. Labels do not say permanent, but they do not say temporary either. 89. How will large debris lodged in the middle of the concrete channel get removed {say, at station 9+00)? Will equipment need to get down into the channel? If so, how? Provide access road and easement {include file number) along full length of channel? WCE Response: With the revised design, large debris that fits through the box culvert would flow strait through the open channel and would be pushed against the angled trash racks of the headwall as flood waters rise the debris would float/rise up the trash rack, thus clearing the inlet of debris. Additionally, a maintenance road and gate are placed above the headwall. With a mini-excavator any piled debris can be removed safely. See sheet C5.1 for more detail. Per previous discussions, easements will be recorded and file numbers added after the CLOMR is received. ✓ A review of the plans verifies that the intent City's comment has been adequately addressed, with proposed trash rack and access to channel being provided. 90. Please provide a curb inlet at low point STA 19+56.36 and near STA 22+75. Provide stationing for all curb inlets. Limit maximum spacing of curb inlets to 100', or less depending on curb inlet calculations. Locate the curb inlets to maximize swale treatment. WCE Response: Inlets have been added. Curb inlet location table added to sheet C3.11. Spacing has been revised per 100 ft maximum and/or to maximize treatment. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 91. For Construction Note #14 and the existing drywell to be abandoned, please specify that decommissioning drywells shall comply with WAC 173-218-120 and WSDOT Specs 7-05.3{2) Abandon Existing Manholes. The following is required: a. Remove any structure within three feet of the land surface, b. Backfill up to three feet below the land surface with material that is uncontaminated, chemically and biologically inert, and that drains equal to or more slowly than the native material surrounding the UIC well, and c. Fill the remaining three feet directly below the land surface with native soil or other structurally sound material common with current engineering practices. WCE Response: Construction note revised and decommissioning notes added to sheet C3.11. ✓ A review of the plans verifies that the City's comment has been adequately addressed. August 1, 2019 Henry Allen, PE Page 51 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology / Hydraullcs Detailed Review 92. For Construction Note #16, please provide Thorpe Road stationing and offsets for each catch basin for construction clarity. WCE Response: Construction note directs to sheet C5.1 for location info. -+ In reviewing the plans, there is no Sheet C5.1. The note refers to Sheet C5.01, there is no Sheet C5.01 either. The detail appears to be on Sheet C5.10, but there are no callouts for the catch basin and piping locations on the Box Culvert Detail. There are similar issue with Note 17. 93. In the Centerline/Sawcut Profile, please provide the missing grade break elevations for STA's 23+35.57 and 23+55.57. WCE Response: Grade break elevations have been added. ✓ A review of the plans verifies that the City's comment has been adequately addressed. Sheet C3.12 (Chester Creek Culvert Extension) 94. Please revise the sheet title and Section 'A' title to match the Sheet Index on Sheet C0.0. WCE Response: Titles have been revised to match. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 95. Please label Thorpe Road. WCE Response: Thorpe Road has been labeled. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 96. For Section 1, a. Verify the ROW/easement dimensions. Sheet C0.3 shows a ROW width of 55'. WCE Response: ROW width revised to show 55 feet. ✓ A review of the plans verifies that the City's comment has been adequately addressed. b. Reference Std. Plan R-102 for the curb and gutter, WCE Response: Reference added to Std. Plan R-102. ✓ A review of the plans verifies that the City's comment has been adequately addressed. c. Reference Std. Plan R-103 for the sidewalk, WCE Response: Reference added to Std. Plan R-103. ✓ A review of the plans verifies that the City's comment has been adequately addressed. August 1, 2019 Henry Allen, PE Page 52 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology / Hydraulics Detailed Review d. Specify how the curb and gutter will be secured to the precast panels, WCE Response: Curb and gutter will be doweled to the precast culvert sections. ✓ A review of the plans verifies that the City's comment has been adequately addressed. e. Set the top of sidewalk flush with the top of curb and gutter, WCE Response: Top of sidewalk revised to be flush with top of curb. ✓ A review of the plans verifies that the City's comment has been adequately addressed. f. The 4" HMA is the minimum thickness, it will need to vary to get the cross-slope. WCE Response: Note revised for 4" min thickness and thickness varies to achieve cross slope. ✓ A review of the plans verifies that the City's comment has been adequately addressed. g. Specify a tack coat shall be applied to the precast panel decking prior to placing the asphalt paving, WCE Response: Note added to tack coat prior to paving. ✓ A review of the plans verifies that the City's comment has been adequately addressed. h. Provide a guardrail at the north end of the box culvert extension. WCE Response: A guardrail has been called out on the north end of the box culvert extension. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 97. For Section 2, a. Provide construction details for the precast panel and footings i. How will precast panel be secured to the existing culvert? WCE Response: The panel has been revised to a precast box culvert and the details are provided on sheet C5.21. Shop drawings to be provided at time of construction. -+ In review of the plans, the box culvert detail is located on Sheet C5.11, not C5.21. Otherwise, the city's comment is adequately addressed. ii. Footings need to be at or below elevation of existing culvert footings. WCE Response: Note added to install new footing at or below existing footings. ✓ A review of the plans verifies that the City's comment has been adequately addressed. August 1, 2019 Henry Allen, PE Page 53 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology/ Hydraulics Detalled Review b. Why is the FG@CL lower than the top of the precast panel? WCE Response: Section revised to show FG above culvert deck. ✓ A review of the plans verifies that the City's comment has been adequately addressed. Shee'I C3.20 -C3.23 (Madison Road P&P) 98. In public meetings, street lights were promised along Madison Road. Please show the light locations and specify that the lights will be installed with the plat. Specify necessary conduit sleeves to be installed with the frontage improvements. WCE Response: Street lights have been added at the future street intersections. See construction note 19. ~ In reviewing the plans, street lights were added at the future street intersections, and notes were added to sheets. However, the location appears to be outside of the Madison Road ROW, and west of the intersections. The City will need to verify if the location of the future lights meets the intent of the request. Sheet C3.20 (Madison Road P&P} 99. See all applicable review comments from Sheet C3.11 for this sheet. (78) For Construction Note #6, reference the roadside swale section in the detail sheets, in addition to S-130. WCE Response: Reference has been revised to Detail A on sheet C0.3 and Std Plan S-130. ~ In reviewing the plans, note refers to sheet C.03 (not C0.3), this typo is on remaining Madison Road sheets as well. 100. Please provide stationing for all curb inlets. Limit maximum spacing of curb inlets to 100', or less depending on curb inlet calculations. Locate the curb inlets to maximize swale treatment. WCE Response: Curb inlet location table added to sheet C3.20. Spacing has been revised per 100 ft maximum and/or to maximize treatment. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 101. Roadside swales are considered flat for volume calculations where the swale bottom slope is 1 % or less. Address all roadside swales where the street grades exceed 1 %. WCE Response: Check dams have been added where slope exceeds 1 %. See sheet C0.3 for check dam detail. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 102. For Construction Note #9, utilities shall not be located in sidewalks per SVSS 6.2.2 &6.2.3. August 1, 2019 Henry Allen, PE Page 54 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology/ Hydraulics Detailed Review WCE Response: Construction note 9 has been revised to have utilities relocated outside of sidewalk. Relocation to be coordinated with utility company. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 103. Construction Note #14 -channel access may need to be shown for the full length of the channel. WCE Response: With the design change, channel access has been relocated to another sheet ✓ A review of the plans verifies that the City's comment has been adequately addressed. Note has been changes to "Reserved". 104. Construction Note #16 at STA 10+75 should reference a driveway approach with a separated sidewalk. See Standard Plans R-110 through R-112. WCE Response: With the design change the driveway has been removed. ✓ A review of the plans verifies that the City's comment has been adequately addressed. Sheet C3.21 (Madison Road P&P) 105. See all applicable review comments from Sheet C3.20 for this sheet. (78) For Construction Note #6, reference the roadside swale section in the detail sheets, in addition to S-130. WCE Response: Reference has been revised to Detail A on sheet C0.3 and Std Plan S-130. -+ In reviewing the plans, note refers to sheet C.03 (not C0.3). Similar reference errors throughout the plan set. (100) Please provide stationing for all curb inlets. Limit maximum spacing of curb inlets to 100', or less depending on curb inlet calculations. Locate the curb inlets to maximize swale treatment. WCE Response: Curb inlet location table added to sheet C3.20 per note on this sheet. Spacing has been revised per 100 ft maximum and/or to maximize treatment. ✓ A review of the plans verifies that the City's comment has been adequately addressed. (101 )Roadside swales are considered flat for volume calculations where the swale bottom slope is 1 % or less. Address all roadside swales where the street grades exceed 1 %. WCE Response: Not applicable on this section of Madison Rd as grades do not exceed 1 %. ✓ A review of the plans verifies that the City's comment has been adequately addressed. August 1, 2019 Henry Allen, PE Page 55 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology / Hydraulics Detailed Review (102)For Construction Note #9, utilities shall not be located in sidewalks per SVSS 6.2.2 & 6.2.3. WCE Response: Construction Note 9 has been revised to have utilities relocated outside of sidewalk. Relocation to be coordinated with utility company. ✓ A review of the plans verifies that the City's comment has been adequately addressed. Sheet C3.22 (Madison Road P&P) 106. See all applicable review comments from Sheet C3.21 for this sheet. (78) For Construction Note #6, reference the roadside swale section in the detail sheets, in addition to S-130. WCE Response: Reference has been revised to Detail A on sheet C0.3 and Std Plan S-130. (100)Please provide stationing for all curb inlets. Limit maximum spacing of curb inlets to 100', or less depending on curb inlet calculations. Locate the curb inlets to maximize swale treatment. WCE Response: Curb inlet location table added to sheet C3.20 per note on this sheet. Spacing has been revised per 100 ft maximum and/or to maximize treatment. ( 101) Roadside swales are considered flat for volume calculations where the swale bottom slope is 1 % or less. Address all roadside swales where the street grades exceed 1 %. WCE Response: Not applicable on this section of Madison Rd as grades do not exceed 1 %. (102)For Construction Note #9, utilities shall not be located in sidewalks per SVSS 6.2.2 & 6.2.3. WCE Response: Construction Note 9 has been revised to have utilities relocated outside of sidewalk. Relocation to be coordinated with utility company. ~ This sheet was not included in the submittal, verifications cannot be made on comments. It can be assumed that similar incorrect sheet references as indicated on prior and following sheets will apply to this sheet as well. Sheet C3.23 (Madison Road P&P) 107. See all applicable review comments from Sheet C3.22 for this sheet. (78) For Construction Note #6, reference the roadside swale section in the detail sheets, in addition to S-130. WCE Response: Reference has been revised to Detail A on sheet C0.3 and Std Plan S-130. ~ In reviewing the plans, note refers to sheet C.03 (not C0.3) August 1, 2019 Henry Allen, PE Page 56 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology / Hydraulics Detailed Review (100)Please provide stationing for all curb inlets. Limit maximum spacing of curb inlets to 100', or less depending on curb inlet calculations. Locate the curb inlets to maximize swale treatment. WCE Response: Curb inlet location table added to sheet C3.20 per note on this sheet. Spacing has been revised per 100 ft maximum and/or to maximize treatment. ✓ A review of the plans verifies that the City's comment has been adequately addressed. Table is located on sheet C3.23. (101 )Roadside swales are considered flat for volume calculations where the swale bottom slope is 1 % or less. Address all roadside swales where the street grades exceed 1 %. WCE Response: Not applicable on this section of Madison Rd. ✓ A review of the plans verifies that the City's comment has been adequately addressed. (102)For Construction Note #9, utilities shall not be located in sidewalks per SVSS 6.2.2 & 6.2.3. WCE Response: Construction Note 9 has been revised to have utilities relocated outside of sidewalk. Relocation to be coordinated with utility company. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 108. In public meetings, it was mentioned that the project sidewalk would extend and connect to the sidewalk by the school to the north. Please investigate. WCE Response: The sidewalk has been shown and called out to extend to the existing sidewalk to the north approximately 300'. The meandering path ends at the property line. A 5' walk has been called out per construction note 21. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 109. For the pedestrian ramp at the southwest corner of Madison Road and Road 'C', please connect the ramp to the 1 0' asphalt path. WCE Response: Ramp has been revised to connect to path ✓ A review of the plans verifies that the City's comment has been adequately addressed. Sheet C3.24 {Madison Road Storm Pipe Crossings) -+ This sheet appears to have been switched to sheet C5.22. It is incorrectly referred to throughout the plan set. It is also now called Madison RD Culvert Plan. 110. For Sections 'A' & 'C', provide a 0.1 0' min. drop through the catch basin per SRSM 8.5.2. WCE Response: A 0.1' drop has been added to the catch basins. August 1, 2019 Henry Allen, PE Page 57 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology/ Hydraulics Detailed Review ~ In review of the plans, catch basins do not appear to have a 0.1' drop. This is the case for all catch basins. 111. For Sections 'C' & 'D', the soil cover over the culvert appears to be less than 1 '. SRSM 8.4.2 requires culverts with soil cover less than 2' to be ductile iron. Soil cover is measured from top of pipe to bottom of asphalt pavement. Increase the soil cover to 1' and provide pipe data supporting the shallow soil cover for a CMP material. WCE Response: The pipe has been revised to call out DI. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 112. Please specify the type of CMP. WCE Response: A note specifying the CMP has been added. WSDOT STD. 9-05.1 (2). ✓ A review of the plans verifies that the City's comment has been adequately addressed. 113. Provide trash racks at the inlets of all the cross-culverts since the outlet of the 60" pipe has a trash rack. WCE Response: Trash racks have been added. See sheet C3.24 for details. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 114. Structures at the 60" RCP should be catch basins not manholes (per the narrative). Please show the sump. WCE Response: Manholes have been revised to catch basins with sumps. See construction note 3 on sheet C5.3. ~ A review of the plans verifies that the City's comment has been adequately addressed. However, there is no Sheet C5.3. This could be referring to Note 3 on C5.20. It is incorrectly referred to throughout the plan set. 115. Please revise the sheet title to match the Sheet Index on Sheet co.a. WCE Response: The sheet title has been coordinated with the sheet index. ~ A review of the plans verifies that the City's comment has been adequately addressed. However, Sheet C3.24 was switched to C5.22 and the references to this sheet needs to be updated throughout the plan set. Sheet C3.30 (Intersection Details) 116. For all details, label existing and proposed ROW's. WCE Response: Existing and proposed ROWs have been labeled. August 1, 2019 Henry Allen, PE Page 58 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology / Hydraulics Detailed Review ✓ A review of the plans verifies that the City's comment has been adequately addressed. 117. For the Curve Table, please specify that the data is taken at the back of curb. WCE Response: A note has been added to this affect. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 118. For Detail 1: a. Provide a widened border easement per SVMC 20.20.090, WCE Response: The border easements have been revised ✓ A review of the plans verifies that the City's comment has been adequately addressed. b. Provide curve data and spot elevations for the south edge of pavement, WCE Response: A radius length and spot elevations have been added. ✓ A review of the plans verifies that the City's comment has been adequately addressed. c. Adjust the separated sidewalk location to the back of the ramp, WCE Response: The sidewalk has been revised to meet the back of the ramp. ✓ A review of the plans verifies that the City's comment has been adequately addressed. d. Label the gutter slope at the base of the ramp. WCE Response: The gutter slope has been labeled. ~ In reviewing the plans, the gutter slope is labeled on both sides of the base of the ramp, but the base of the ramp is not labeled. The TP elevations labeled at the base of the ramp indicate a slope of 6.0%. Max slope at the base of the ramp should be 2% or less. ~ New Comment: Thorpe is mis-spelled (Thopre) in Details 1 and 2. 119. For Detail 2: a. Rename 'Dishman-Mica Road' to 'Madison Road', WCE Response: The road name has been revised. ✓ A review of the plans verifies that the City's comment has been adequately addressed. b. Provide a widened border easement per SVMC 20.20.090, WCE Response: The border easements have been revised August 1, 2019 Henry Allen, PE Page 59 of 76 Reference: City of Spokane Valley-Painted Hills Development CLOMR, Ordinance, & Hydrology / Hydraulics Detailed Review ✓ A review of the plans verifies that the City's comment has been adequately addressed. c. Revise the BCR top of curb spot elevation on Thorpe Rd to match the profile, WCE Response: The BCR has been revised to match the road profile. ✓ A review of the plans verifies that the City's comment has been adequately addressed. d. Verify that the gutter slope at the base of the pedestrian ramp is 2% or less. WCE Response: The gutter slope has been labeled and a max of 2% slope in front of the pedestrian ramp has been called out. ✓ A review of the plans verifies that the City's comment has been adequately addressed. Max slope of 2% is not called out. However, the gutter slope is 1.16%, meeting the intent. 120. For Details 3-6: a. Revise the BCR top of curb spot elevations on Madison Rd to match the profile, WCE Response: The BCRs have been revised to match the profile. ✓ A review of the plans verifies that the City's comment has been adequately addressed. b. Verify that the gutter slopes at the base of the pedestrian ramps and the cross-slope along the crosswalk are 2% or less, WCE Response: The gutter slope has been labeled and a max of 2% slope in front of the pedestrian ramp has been called out. • In reviewing the plans, the gutter slope is labeled on both sides of the base of the ramp, but the base of ramp is not labeled. In detail 2, the TP elevations labeled at the base of the ramp indicate slopes of 17%+ at base of ramps. Max slope at the base of the ramp should 2% or less per SP R- 107. c. The longitudinal slope of Madison Rd at each intersection is less than 0.8%. Adjust the Madison Rd BCR top of curb spot elevations to create a 0.80% minimum longitudinal slope without a cross gutter or a 0.50% minimum longitudinal slope with a cross gutter (SVSS 7.5.4) or lower the BCR spot elevations on Roads 'A' -'D' so the intersections slope to the west. WCE Response: The elevations have been kept so that water flows around the intersections to the east and will enter the roadside swales for treatment. • In reviewing the plans, Details 5 and 6 do not provide a 0.50% minimum longitudinal slope on the southwest curb returns. 121. ForDetail7: August 1, 2019 Henry Allen, PE Page 60 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology/ Hydraulics Detailed Review a. Verify that the gutter slope at the base of the pedestrian ramps and along the cross walk are 2% or less, WCE Response: The gutter slope has been labeled and a max of 2% slope in front of the pedestrian ramp has been called out. -+ In reviewing the plans, Details 7 provides a max of 2% slope. However, the southeast curb return does not provide a 0.50% minimum longitudinal slope. b. Provide the future design of Road 'E', provide curb inlets on Road 'E' at the east BCR's. WCE Response: See sheet C3.03 for the plan and profile of Sundown Rd (Road E). Type 2 curb inlets have been called out on the east BCRs. -+ In reviewing the plans, this is not the case. Top of Curb elevations are not labeled on Sheet C3.03. However, the intersection design indicates flow goes to the east around the curb returns to Sundown. Sundown flows toward the west to the same location. There are no curb inlets at this low spot indicated on the plans for the east BCRs. For Items 122 through 146 the Levee has been removed from the flood control plan including the referenced sheets Sheet C4.0 (Grading Plan) -+ It is unclear what the intent of this sheet is, as nothing is identified outside of overall quantities. Sheet CS.0 (Storm System Overview} 147. Include titles for profiles. WCE Response: Titles have been added to the profiles. -+ In reviewing the plans, there is only one profile. Title is not shown. In addition, none of the sheet callouts are correct on this sheet. Sheets C5.1 to C5.5 do not exist. 148. For upper profile provide stations for all structures. WCE Response: Stationing has been added for structures. ✓ A review of the plans verifies that the City's comment has been adequately addressed. There is only one profile, structures have stations. 149. Construction Notes: a. Provide all applicable details sheets for all notes. August 1, 2019 Henry Allen, PE Page 61 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology/ Hydraulics Detailed Review WCE Response: The brief construction notes have been removed since the sheet is intended as an overview of the flood system. Detailed construction notes are on the storm sheets following C5.0. ~ In reviewing the plans, there are no construction notes on this sheet. Construction notes are on C5.20 and C5.21. b. Note 5 -"manhole" should be "catch basin". Revise standard plan callout and specify depth of sump. Check spelling of "labelled". WCE Response: The construction notes have been removed but where this item shows up on other sheets, the notes have been revised to indicate WSDOT catch basins with 2 foot sumps. ✓ In reviewing the plans, there are no construction notes on this sheet. However, sheets with construction notes have Catch basins labeled in notes (Sheets C5.20 and C5.21 ). Sheet CS.1 (Concrete Channel P&P) ~ In reviewing the plans, this appears to now be Sheet C5.10, and it is now called Box Culvert- Channel-Pipe Plan 150. Plan View: a. Invert elevation of pipe from SD-CB #1 at the channel wall doesn't match the elevation in C5.2. Please verify the pipe slope from SD-CB#I to the concrete channel. WCE Response: IE's have been verified. ~ In reviewing the plans, this is now shown on sheet C5.20. Pipe slopes are labeled 0.0025. Calculating slopes based on box culvert to CDCB #1 inverts (2007.18 and 2006.05) over 451 .40', slope is .0027. b. Include the 100-year stormflow in the system calcs from the pipes originating from SD- CB #1 and SD-CB #2. WCE Response: The peak for the flow through the catch basins will occur much sooner than the peak for the channel flow, therefore, the catch basin flows have not been included. ✓ A review of the plans verifies that the City's comment has been adequately addressed. c. Show the fence located north of the channel in cross section A. WCE Response: The fence has been added. ✓ A review of the plans verifies that the City's comment has been adequately addressed, the detail being referenced is now Detail 4. 151 . Construction Notes: August 1, 2019 Henry Allen, PE Page 62 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology/ Hydraulics Detailed Review a. Note 1 -include C5.21 WCE Response: Note revised to include C5.21 . -+ In reviewing the plans, this no longer appears to be applicable on this sheet. However, Sheet C5.20 has headwall referenced to Sheet C5.1, should be Sheet C5.10. b. Note 4 -include S-121 WCE Response: Note revised to include C-121. ✓ In reviewing the plans, this no longer appears to be applicable on this sheet. However, Note 4 on sheet C5.20 references 18" culvert with rubber gasket indicates see sheet C5.22 for details. Which has a rubber gasket detail. 152. Profile - a. Include slope down to culvert inlet. WCE Response: See revised slope callout on sheet C5.1 ✓ In reviewing the plans, this no longer appears to be applicable on this sheet. Slope is provided on sheet C5.20 b. Check stationing on axis. WCE Response: Stationing has been verified. ✓ In reviewing the plans, this no longer appears to be applicable on this sheet. Again, this applies to sheet C5.20 and appears to have been addressed. 153. Please provide structural calculations and details for the fence, retaining walls and footings in Section 'A' (loads, dimensions, reinforcing, connections, etc.). WCE Response: See sheet C6.0 and C6.1 for structural details for retaining walls and footings. See separate package for calculations. -+ In reviewing the plans, structural details are provided. A separate review of these details and calculations from a licensed structural engineer is recommended. Sheet C5.2 (Box Culvert and Channel Details) -+ In reviewing the Plans, this also appears to be Sheet C5.10 -+ New comment, there are many callouts to sheets that no longer exist or that have been changed. 154. Box Culvert Detail: August 1, 2019 Henry Allen, PE Page 63 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology/ Hydraulics Detailed Review a. General -Provide design details for box culvert and wing wall (design loading, dimensions, elevations, thickness, reinforcing, connections, etc.) WCE Response: See note 2. The contractor will supply shop drawings and design calculations when they pick a supplier of the pre-cast structure. -+ The city will need to decide if this approach is an acceptable solution. b. Plan View - i. Drainage easement is permanent not temporary, WCE Response: The note has been revised. ✓ A review of the plans verifies that the City's comment has been adequately addressed. ii. For culvert alignment line provide a bearing and a station equation where this alignment crosses the Thorpe alignment WCE Response: See sheet CS.1 for bearing and station equation. ✓ A review of the plans verifies that the City's comment has been adequately addressed. Although there is no sheet C5.1, this is on Sheet C5.10. iii. Check stationing of wing walls. WCE Response: Stationing of wing walls are from the culvert alignment and not Thorpe Rd and have been verified. ✓ A review of the plans verifies that the City's comment has been adequately addressed. c. Section 1- i. Label the ROW WCE Response: The ROW has been labeled. ✓ A review of the plans verifies that the City's comment has been adequately addressed. ii. Reference Std. Plan R-102 for the curb and gutter, WCE Response: Standard plan R-102 has been referenced. ✓ A review of the plans verifies that the City's comment has been adequately addressed. iii. Reference Std. Plan R-103 for the sidewalk, WCE Response: Standard plan R-103 has been referenced. ✓ A review of the plans verifies that the City's comment has been adequately addressed. August1,2019 Henry Allen, PE Page 64 of 76 Reference: City of Spokane Valley-Painted Hills Development CLOMR, Ordinance, & Hydrology / Hydraulics Detailed Review iv. Specify how the north curb and the south curb and gutter will be secured to the precast panels, WCE Response: The curb and gutter will be cast onto the deck with dowels epoxied into the deck. The curb will be cast into the box section per the detail on C5.10. ✓ A review of the plans verifies that the City's comment has been adequately addressed. v. Set the top of sidewalk flush with the top of curb and gutter, WCE Response: The top of sidewalk has been set flush with the top of curb and gutter. ✓ A review of the plans verifies that the City's comment has been adequately addressed. vi. Specify a tack coat shall be applied to the precast panel decking prior to placing the asphalt paving, WCE Response: A note specifying a tack coat shall be applied has been added. ✓ A review of the plans verifies that the City's comment has been adequately addressed. vii. Provide guardrails at both ends of the box culvert. WCE Response: A guardrail at the south end of the box culvert has been provided. On the north end of the culvert there is a 7.5' sidewalk and there will also be a 6' chain-link fence for channel access control. There is no room to place a guardrail with these limitations. ✓ A review of the plans verifies that the City's comment has been adequately addressed if the city agrees with WCE Response. viii. Adjust the 12' dimension to start at the face of the 6" curb. WCE Response: The dimension has been revised to 14.5 feet to accommodate standard precast box sections. ✓ A review of the plans verifies that the City's comment has been adequately addressed. ix. Verify the precast panel deck thickness with Section 2. WCE Response: The thickness has been revised so sections 1 and 2 match at 1.5 feet. ✓ A review of the plans verifies that the City's comment has been adequately addressed. x. The 4" HMA is the minimum thickness, it will need to vary to get the cross-slope. WCE Response: A note has been added specifying a varying thickness. ✓ A review of the plans verifies that the City's comment has been adequately addressed. August 1, 2019 Henry Allen, PE Page 65 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology/ Hydraulics Detailed Review xi. For slope down into the culvert inlet - 1. What is the stormwater velocity? WCE Response: Per the Capacity calculation of the box culvert, at a depth of 2 feet and an area of 56.66 sf the velocity of 216.4 cfs (which is twice the 100-year storm rate) has a projected velocity of 3.82 ft per second. Per Open Channel Hydraulics, Chow section 7-9 The Maximum Permissible Velocity Figure 7-3 of the U.S.S.R. Data shows that a 200 mm or 8" particle or rock surface can withstand a velocity of 13 ft per second +/-before scour occurs. ✓ A review of the provided documents verifies that the City's comment has been adequately addressed. 2. Is erosion protection needed? WCE Response: Erosion protection has been added. 1 '-2' angular rip-rap 3' deep has been called out. The erosion protection extends up the slope to the right-of-way. Based upon the information of item 1 with the erosion protection there is no scour anticipated. ✓ A review of the provided documents verifies that the City's comment has been adequately addressed. d. Section 2 -bottom of box is alluvial bed. Calculate scour and set footings below scour. WCE Response: The bottom of the box is rocked as well as the approach within the ROW. See response above. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 155. Channel and Pipe Connection: a. General -Provide design details for channel and trash rack (loads, dimensions, reinforcing, connections, etc.) WCE Response: Structural details have been provided on sheet C6.0 and C6.1. Trash rack details have been provided on sheet C5.6. ✓ A review of the plans verifies that the City's comment has been adequately addressed. b. Plan View - i. There are two set of lines where the channel turns, remove lines that do not represent the channel geometry. WCE Response: The line has been removed and the channel has been hatched to more clearly show where the channel bottom is. ii. Provide channel alignment details and location of pipe inlet. August1,2019 Henry Allen, PE Page 66 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology / Hydraulics Detailed Review WCE Response: The alignment location in the channel bottom is centered iii. Drainage easement is permanent not temporary, WCE Response: The drainage easement label has been revised. ✓ A review of the plans verifies that the City's comment has been adequately addressed. Sheet C5.3 (Madison Pipe P&Pl -+ This is now Sheet C5.20 -+ In review of the plans, many sheet and detail callouts are incorrect because of the sheet numbering\naming change, continuous issue throughout the plan set. 156. Construction Notes: a. Note 3 -Structures at the 60" RCP should be catch basins not manholes (per the narrative}. Call out standard plan for catch basins and specify depth of sump. WCE Response: Note revised to catch basins with 2 ft sump. ✓ A review of the plans verifies that the City's comment has been adequately addressed. b. Note 5 -is the concrete outlet a pad or slab (see C5.4)? WCE Response: Construction note 4 on sheet C5.3 revised to pad. ✓ A review of the plans verifies that the City's comment has been adequately addressed. Take into account that all sheets being referenced are incorrect, the note is on Sheet C5.21. c. Note 7 -specify frame and grate type and include S-121 reference. WCE Response: Construction note 7 has been revised to include Type 1 Frame and Grate and to reference SVSS S-121. ✓ A review of the plans verifies that the City's comment has been adequately addressed. Take into account that all sheets being referenced are incorrect, the note is on Sheet C5.21. 157. Plan view: a. Make sure all structures are accessible for cleaning and have a construction note, WCE Response: Meandering path to be used for access. ✓ A review of the plans verifies that the City's comment has been adequately addressed. b. In 60" pipe why is there a structure at 22+45? August 1, 2019 Henry Allen, PE Page 67 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology/ Hydraulics Detailed Review WCE Response: The pipes and structures have been revised. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 158. Profile: a. Provide stations for all structures on concrete pipe, WCE Response: Stationing has been provided for all structures. ✓ A review of the plans verifies that the City's comment has been adequately addressed. b. Make sure all pipes have length and slope information, WCE Response: Pipe information has been verified for all pipes. ✓ A review of the plans verifies that the City's comment has been adequately addressed. c. Provide offset at 60" pipe outlet. WCE Response: A station and offset from Madison Rd has been provided. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 159. For the culverts under Madison Road, Spokane County GIS shows that there may be a 24" pipe near station 23+50. Please check. WCE Response: All Madison Rd culverts have been surveyed and verified with no evidence of a 24" culvert. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 160. Include the 100-year stormflow in the system calcs from the pipe originating from SD-CB #6. WCE Response: The 100-year flood has been added, please see the flood control narrative ✓ A review of the plans verifies that the City's comment has been adequately addressed. Sheet C5.4 (Bioswale P&P) -+ This is now Sheet C5.30 (Bioswale/Settling Pond P&P -+ In review of the plans, many sheet and detail callouts are incorrect because of the sheet numbering\naming changes, continuous issue throughout the plan set. 161 . Include a short wall at the downstream end of the bioswale as a last trap for sediment. August 1, 2019 Henry Allen, PE Page 68 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology / Hydraulics Detailed Review WCE Response: The design has been revised to include a 1' deep settling pond at the bottom of the bioswale, with a 20' wide rock weir overflow into a 2' deep infiltration pond with a field of drywells set at 1' above the pond surface. This is the design that prevents sediment from entering the gravel gallery. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 162. Plan View: a. Clean up overlapping info, WCE Response: Labels have been revised. ✓ A review of the plans verifies that the City's comment has been adequately addressed. b. Provide dimensions/alignmenUgeometry information for fence, channel and pipes to locate them in space. WCE Response: Station and offset has been provided to Madison Rd to give reference of location in space. ~ In reviewing the plans, the alignment for the bioswale needs horizontal reference information (PCs, PTs, and Curve data). ~ 15' access roads (locations and elevations) are not defined. ~ Locations of drainfield pipes, structures, and limits of drywell rock are not defined. ~ Fence location is not defined. c. Confirm all structures can be accessed for maintenance. WCE Response: An access maintenance road has been provided. ✓ A review of the plans verifies that the City's comment has been adequately addressed. d. Provide all dimensions for hammerhead turn around. WCE Response: Dimensions have been provided. ~ There does appear to be a hammerhead turn around. 15' access roads (locations and elevations) are not defined. e. Provide file number for easement. WCE Response: Space has been provided for inserting file number once easement is recorded after receipt of CLOMR-F comments prior to LOMR submittal per our discussions. ✓ A review of the plans verifies that the City's comment has been adequately addressed. August 1, 2019 Henry Allen, PE Page 69 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology / Hydraulics Detalled Review 163. Construction Notes: a. Make sure all notes have pertinent detail sheets referenced. WCE Response: Verified. + There are references to Detail B that does not exist on Sheets C5.31 and C5.32. + Detail A has seed mix reference to a sheet that does not exist. b. Note 3 -gate should be wider than road. WCE Response: Double swing gate width has been revised and is called out to be 16'. + In reviewing the plans, double swing gate does not appear be called out and it is not evident where the gate is located. c. Note 9 -specify frame and grate type and include S-121. WCE Response: Construction note 9 has been revised to include Type 1 Frame and Grate and to reference SVSS S-121. + A review of the plans verifies that the City's comment has been adequately addressed. However, this is note 6. d. Include note for infiltration head wall. WCE Response: The infiltration headwall has been removed from the design ✓ A review of the plans verifies that the City's comment has been adequately addressed. 164. Bioswale Inlet Cross Section: a. Provide design details (dimensions, elevations, thickness, reinforcing, connections, etc.). WCE Response: See sheet C6.0 and C6. 1for structural details. + Structural details are provided on these sheets. It is recommended structural calculations and details be reviewed by a licensed structural engineer. b. Provide details for trash rack. WCE Response: See sheet C5.3 for trash rack details. ✓ A review of the plans verifies that the City's comment has been adequately addressed. Although these are located on Sheet C5.30. c. In upper drawing check the orientation of the section arrows. August 1, 2019 Henry Allen, PE Page 70 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology / Hydraulics Detailed Review WCE Response: Revised. ✓ A review of the plans verifies that the City's comment has been adequately addressed. d. Include the concrete level spreader in the hydraulic calcs. WCE Response: The level spreader has been added to the west consultants' calculations. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 165. Typical Bioswale Section A a. Call out minimum depth of section. WCE Response: The minimum? foot depth of the section has been added. ~ Minimum depth of section is noted as 6' to bottom of treatment soil for this section. Treatment soil is identified as 1.5' deep, indicating 4.5' of depth to bottom of swale. If 7' is the intended minimum depth of the bioswale, it is not identified correctly. b. The O&M manual says the side slopes are 3:1, please correct. WCE Response: Manual has been revised to 2:1 side slopes. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 166. Narrative says bioswale will be seeded not sodded, please revise. WCE Response: Note revised to seed the bio-swale. ~ Note to be seeded was added, but it is referring to a seed mix on a sheet that does not exist. 167. Profile -show proposed grade. WCE Response: The proposed grade of 1.00% has been added. ✓ A review of the plans verifies that the City's comment has been adequately addressed. 168. Include the 100-year stormflow in the system calcs from the pipe originating from SD-CB #7. WCE Response: The peak for the flow through the catch basin will occur much sooner than the peak for the mainline flow, therefore, the catch basin flow has not been included. ✓ A review of the plans verifies that the City's comment has been adequately addressed. Sheet C5:5 (Infiltration P&P) ~ This sheet is now broken up into Sheets C5.31 and C5.32. August 1, 2019 Henry Allen, PE Page 71 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology/ Hydraulics Detailed Review -+ Construction notes refer to a Detail B, that does not exist. They also refer to Section C on the incorrect sheet. -+ References on previous sheets have not been updated to reflect new sheet numbers and details. 169. Plan View: a. Provide alignment information for pipes and structures to locate them in space. WCE Response: Station and offset of Madison Rd has been provided at corners to locate them in space. -+ This only shows location of pond bottom, not structures within the pond. Locations of pipes and structures are not adequately identified within the drainfield. b. Confirm all structures - i. Have rim and inlet elevations and that elevations match those in profile WCE Response: Rim and invert elevations have revised and verified. -+ Invert elevations are not noted anywhere in plan or profile. -+ Detail F on Sheet C5.32 has pond bottom noted at 1996.8. Infiltration pond notes indicate a bottom elevation of 1995.80 and minimum berm elevation of 2002.80 (7' depth}. Typical sections shown 6' minimum from top of berm to bottom of treatment soil. Together, this information would make a depth of 4.5'. Overall, there is no consistency in callouts and the intended design is unclear. -+ Section F on sheet C5.32 shows both Drywell Rims and Pond Bottoms to be 1996.80, with 1.0' between them. Notes indicate pond bottom of 1995.8. It is not clear which one is correct. ii. Can be accessed for maintenance (especially by Vactor per the project narrative}. WCE Response: Distance has been verified. ✓ A review of the plans verifies that the City's comment has been adequately addressed. c. Provide structure numbers to relate structures to those in the profile. WCE Response: Structure numbers have been provided in plan and profile views. -+ Structure numbers are not provided in plan or profile. d. Provide file number for easement. WCE Response: Space has been provided for inserting file number once easement is recorded after receipt of CLOMR-F comments prior to LOMR submittal per our discussions. August1,2019 Henry Allen, PE Page 72 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology / Hydraulics Detailed Review ✓ A review of the plans verifies that the City's comment has been adequately addressed. 170. Profile: ~ Typical sections are used in lieu of plan and profiles. This is acceptable if a reference location is provided to each row of drywells. a. Provide stations at structures. WCE Response: Stationing has been provided for structures. ~ Stations are not provided. As noted above, a reference location could be used in lieu of stationing, if one was provided. b. Show proposed grade. WCE Response: The proposed grade matches existing grade. ~ It appears that it is the existing grade that is not shown, rather than proposed. Unless this pond already exists and happens to be at the exact location as the proposed cross-section throughout the entire pond. 171. Construction Notes: a. Make sure all notes have pertinent detail sheets and standard plans referenced. WCE Response: Verified. ~ Notes refer to sections that do not exist as well to details on incorrect pages; some are not even called out. b. Note 7 -specify drywell type. WCE Response: The drywells are per City of Spokane Valley standards with additional barrels to achieve added depth. ~ Tripe Depth Drywell per COSV Standard plan S-101 is referenced. Type 'B" drywells only go to double depth in S-101, so this is not a standard drywell installation. In addition, these are quadruple depth because the of the added section for perforated pipe and extended gravel gallery at the bottom of the drywells. Additional detail is required for drywell installing. c. Note 8 -specify fabric class. WCE Response: The fabric class has been specified. ✓ A review of the plans verifies that the City's comment has been adequately addressed. It is called out in the standard plan reference. August 1, 2019 Henry Allen, PE Page 73 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology / Hydraulics Detailed Review d. Note 9 -provide standard plan. WCE Response: Note 9 has been revised. + Note 9 does no longer exists, it is not known which note this would be referring to, therefore which standard it should call out. e. Include note for infiltration head wall. WCE Response: The infiltration headwall has been removed from the design. ✓ A review of the plans verifies that the City's comment has been adequately addressed. + New comment. The City is concerned about the erodability of fill due to the very large volume proposed for fill material, and its proximity to flood plain areas between the proposed alignment of 43rd Street and Painted Hills Street. The entire set of submittal documents has been scanned for mention of a fill specification for the material to be used to construct embankments and particularly roadway embankments throughout the project site. No mention was found. Please provide. Sheet C6.6 (Infiltration Headwall Details) 172. Provide design details for headwall, channel and trash rack (loads, dimensions, elevations, thickness, reinforcing, connections, angles, etc.). 173. Call out spacing between pipes. 174. Provide stations at end of channel and at pipe inverts. WCE Response: The infiltration Headwall has been removed from the design. ✓ A review of the plans verifies that the City's comment has been adequately addressed. Sheet C6.7 (Infiltration Headwall Details) 175. Drain field cross section -provide complete spec reference. 176. 24" HOPE Cross Detail -specify filter fabric and how it is attached to pipe. WCE Response: The design has been revised. ✓ A review of the plans verifies that the City's comment has been adequately addressed. Sheet C9.0 (S WPPP Cover) 177. Legend -there isn't a storm drain pond, please revise. WCE Response: "Pond" revised to "facility" as we don't want washout at the bio-swale. ✓ A review of the plans verifies that the City's comment has been adequately addressed. August 1, 2019 Henry Allen, PE Page 74 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology / Hydraulics Detailed Review 178. Provide protection at infiltration headwall. WCE Response: Protection at the infiltration headwall has been added. ✓ A review of the plans verifies that the City's comment has been adequately addressed. Sheets C-9.0 (SWPPP Cover) 179. Legend -there isn't a storm drain pond, please revise. WCE Response: "Pond" revised to "facility" as we don't want washout at the bio-swale. ✓ A review of the plans verifies that the City's comment has been adequately addressed. Sheets C10.0 to C10.2 (Signing and striping plans) ✓ New Comments: These are added sheets to the plan. Based on a review of signing and striping plans: Below are items of note. + MUTCD standards should be identified in addition to any Spokane Valley Standard plans identified. + Per COSV Street Standards 4.10: TEMPORARY TRAFFIC CONTROL PLAN: A temporary traffic control plan shall be included with the right-of-way permit. The plan shall be in detail appropriate to the complexity of the project per MUTCD Chapter 6 B. o Comment: This will be required prior to issuing permit for work within public right-of-way. + Per COSV Street Standards 4.11.3 SIGNING PLAN: + The permanent signing plan shall: Show the longitudinal location of each sign (horizontal offset and station) o Comment: Only station has been noted, offsets are not provided in plan set. + Specify the sign legend and sign type (from MUTCD and International Fire Code); o Comment: Street name signs are not indicated in the plan set (existing or proposed). + Specify the sign size and applicable standard plan; o Comment: Sign sizes are not indicated in the plans. + Refer to Standard Plan R-140 for post and base dimensions and installation plan; o Comment: This is not noted in the plans. August1,2019 Henry Allen, PE Page 75 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology / Hydraulics Detailed Review -+ Specify the blank gauge of the sign; and, o Comment: This is not noted in the plans. -+ Note the reflectorization provided. o Comment: This is not noted in the plans. -+ Per COSV Street Standards 4.11.4 STRIPING PLAN: -+ The striping plan shall show: Color and type; Lane widths, taper lengths, storage lengths, etc.; Striping/skip interval; o Comment: Lane widths are not provided on sheet C10.2 -+ Any construction or application notes, (e.g., application temperatures, surface cleaning methods to be used prior to application, etc.); o Comment: Not addressed in plan set. -+ Typical treatments for acceleration/deceleration lanes, turning lanes, and crosswalks; o Comment: Not addressed in plan set. -+ Station and offset or dimensions to all angle points, symbol locations, and line terminations. o Comment: Offsets not identified in plan set. Radii needs to be identified for all radial transitions. 6 CLOMR APPLICATION The City's comment as of 8/20/18: "The CLOMR Application has been revised since the City's rejection of the Levee Design. A CLOMR-F application has been provided." The application has been further revised to a CLOMR Application, recognizing the proposed flood plain alteration. References to a CLOMR-F has been deleted. 6.1 NARRATIVE 180. Page 9 & page 14 paragraph 1-mentions that the infiltration facility maximum design flow is 84 cfs. Where was that flow rate obtained? 181. Page 13, end of 2nd paragraph -may want to also reference the Geotech investigation for the latest drywell design which is the document titled "Full-Scale Drywell Testing ... ". 182. Please include page numbers for all the narrative's pages. HEC-RAS model 183. Proposed Madison concrete pipe is initially 4 feet in diameter then goes to 5 feet in diameter but the second pipe in the model is 6 feet in diameter, please revise and update the text in the narrative. 184. At the outlet of the 5-foot pipe include the concrete level spreader (sheet C5.4). August 1, 2019 Henry Allen, PE Page 76 of 76 Reference: City of Spokane Valley -Painted Hills Development CLOMR, Ordinance, & Hydrology / Hydraulics Detailed Review WCE Response: WCE did not provide responses to these comments. ✓ The above comments have been superseded by a detailed review of the updated CLO MR Application. All the above comments are either no longer relevant or they have been addressed. 6.2 FORMS 185. Riverine Structures Form -does the new culvert under Thorpe need to be included in one of the C. BRIDGE/CULVERT sections? WCE Response: WCE did not provide response to these comments. ✓ A Riverine Structures Form has been included in the revised CLOMR submittal, including hydraulic analyses of the box culvert proposed under Thorpe Road; the culvert at Highway 27 for the entry to the proposed pipe in the Gustin Ditch, and the concrete channel at the golf course. Design w;th community in niind ~ Stantec CLOMR Submittal Initial Screening Checklist Project Name: Painted Hills Development Date: December 19, 2018 Location: City of Spokane Valley, Washington Reviewer: Zach Whitten, PE - Required Received Item Descrlptlon (Y/N) (Y/N) Comff'.le_n_t Provide a written description, certified by a registered Professional Engineer. A narrative is provided but is not sealed. Initial screening of the narrative appears to be unclear, A lot of documents Sealed Report/Narrative about the purpose of the request, the scope of the proposed project, and y Y/N were provided but it is unclear if all documents are to be submitted with CLO MR or how they tie-in to application. the methodology used to analyze the project effects. Review Fee Payment Not included as part of the initial CLOMR submittal y y Payment of $7,000 is stated but no basis given. CLOMR has a unique pay structure and should be reviewed Provide completed forms applicable to your request. Ensure that MT-2 Form MT-2 forms are completed but it appears that the there are 3 streams being affected but only one Form 2 and Form 3 is filled out. Forms should be filled out for each affected stream/reach. MT-2 Application Forms 1 signed by the requester, certifying engineer and each community affected y y Also, no community signature is provided. Given the study location includes two communities (City of Spokane by the revision. Valley and Spokane County). two signatures may be required Community Is the acknowledgment of the study from all communities effected by y N Does not appear that the County of Spokane has acknowledged project. Acknowledement change State Approval If required, does the application required approval from the state N N Does not appear that the State of Washington requires special approval Provide a FEMA acceptable hydrologic analysis in digital format, drainage Hydrologic models are provided digitally but a detailed writeup of the analysis is not provided within the CLO MR Hydrologic Analysis area map and associated backup information (e.g., calculations used to y N application. More detail will need to provided. Also, no spatial files associated with models were found. Spatial determine lag time, CN and loss values as well as landuse and soil maps), files will be required to verify model validity Provide a FEMA acceptable hydraulic analysis in digital formaand associated Hydraulic models are provided digitally but not spatial files or calculation sheets were received with model. All Hydraulic Analysis backup information (e.g., calculations used to determine manning's n-y Y/N spatial files associated with the models should be included values. etc.) Submit an analysis of sediment transport. lf sediment transport will not Sediment Transport affect the base flood elevation (BFE) or a structure, then indicate that this y N No statement about sediment transport is made. Will sediment transportion have an effect on the perfomance of section is not applicable, and include an explanation as to why a sediment the infiltration basin? A statement should be provided regarding this answer analysis was not performed. Workmaps are provided but are not stamped. No other topography was provided thus in workmap with the Certified Topographic Please provide a certified topographic work map that meets the mapping topography will need to be stamped. Also, the application states that the LiOAR that was used in the effective 2003 y Y/N study was used, but no shapefiles of the UOAR, statement of accuracy or survey report was provided. Though the Work Map requirements outlined in MT-2 Form 2 UDAR may have been used in the effective study, the reviewer will not have access to the data, nor will he or she know if hte mapping meets current standards Submit a revised FIRM, at the scale of the effective FIRM, which shows the revised boundary delineation of the base floodplain, 0.2-percent-annual An noted FIRM Provided. It is noted that a portion of the floodplain outside of the highlighted "affected area" is Annotated FIRM chance floodplain, and regulatory fioodway and how it ties into the y y different from the effective floodplain. Did this study modify this floodplain? It is located just east of the "affected boundary delineation shown on the effective FIRM at the downstream and area11 polygon. upstream ends of the revised reach Annoted FWDT Submit Annotated Floodway Data Table comparing the results of the y y Provided hydraulic models corresponding to those discussed in the Narrative. Annotated Profiles Submit annotated revised flood profiles y y Provided Proposed/as-built plans All plans asscoaited with project, as-built or proposed, should be submitted y y Provided with a certified engineer stamp. 65.10 Requirements If the project involves levees, floodwalls or berms, documentation should be N N Not required for this study provided that demonstrates that 65.10 requirements have been meet. Submit example documentation of legal notice to be sent to all affected Property Owner property owners within and outside of the community, explaining the y N Not provided Notification impact of the proposed action on their property. Documentation to be sent after technical review is complete. If the revision result in changing or establishing floodway boundaries, please Floodway Notice provide floodway public notice or a statement by your community that it has y N Not provided notified all affected property owners, in compliance with NFIP regulation Subparagraph 65.7(b)(l). () Stantec CLOMR Submittal Initial Screenlhg Checklist -- R~ulred R«elved Item Destr'lptlon (Y/N) (Y/N) Com,:n~t Endangered Species Act Submit documentation of compliance with the ESA requirements. To learn y y Provided Compliance more about ESA compliance, please see the MT-2 lnstructlons manual. Operation and If the request Involves a benn, levee, flood wall, dam, and/or detention basin project, please submit an officially adopted maintenance and y y Provided Maintenance Plan operation plan. Provide digital computer-aided design (CAD) or geographic information system (GIS) data that are spatially referenced that are associated with i=tles associated With determining floodplain boundaries, flood profiles, floodway boundaries, all data necessary to Digital Spatial Data determining floodplain boundaries, flood profiles, floodway boundaries, all y N demonstrate that the physical modifications to the floodplain, hydrologlc and hydarulic modeling need to br data necessary to demonstrate that the physical modifications to the provided. the submittal did not contain any of these files. floodplain, hydrologlc and hydarullc modeling, etc. 4-/ Painted Hills EIS Review September 19, 2019 Mr. Read Stapleton, AICP DOWL 720 SW Washington St, Ste 750 Portland, OR 97205 Community & Public Works Department I 0210 E Sprague A venue •·Spokane Valley WA 99206 Phone: (509) 720-5000 • Fax: (509) 720-5075 • www.spokanevalley.org Email: permitcenter@spokanevalley.org Subject: Review of Draft EIS, dated May 31, 2019 Dear Mr. Stapleton: Thank you for the draft environmental impact statement (DEIS) you provided for review. This letter is intended to identify issues and topics on which the City, as the lead agency for whom the DEIS has been prepared, requests additional research and examination in order to meet its requirements under SEPA (chapter 43.21C RCW). Alternatives assessment SEP A requires that environmental impact statements present and analyze reasonable project alternatives, one of which is to be considered a "no action" alternative. You have presented the "no action" alternative and a single project alternative that is based on essentially the same grading and floodwater management approach as the subject proposal. There should be a more extensive discussion of how the issue of reasonable project alternatives was considered. The DEIS should discuss how the concept of reasonable alternatives (WAC 197-11-440(5)(b), 197- 11-786) was used to limit the identified alternative to a proposal so similar to the subject proposal. There should be a discussion of how the single project alternative was determined to have a lower environmental cost or decreased level of environmental degradation than the subject proposal. WAC 197-11-440(5)(b). The City is concerned that the DEIS does not adequately explain other potentially feasible and more environmentally benign development alternatives of the site that avoids or minimizes impacts to the flood zone and other environmental aspects of this area as required by SEP A and recommends that you present and analyze such an alternative in the DEIS. Flood Hazard Management The City's consultant engineer has reviewed the underlying CLOMR Application completed by WEST Consultants and the Flood Control Narrative provided by Whipple Consulting Engineers ( collectively referred to as the "hydraulic model materials") as described in its comment letter to Painted Hills EIS Review Mr. Read Stapleton Sept. 19, 2019 Page 2 the City dated August 1, 2019 and provided to Whipple Consulting Engineers on August 28, 2019. An overall completeness and methodology review indicated that the analysis is close to a complete FEMA submittal. However, the greater intensity of land use at the site as a result of the proposal requires detailed discussion of risks associated with the off-site and on-site storm drainage and channel improvements that are proposed. The components of the floodwater management system need to be addressed in relation to potential points of failure and consequences of failure. In general terms the DEIS should contain a discussion of risk assessment and develop an analysis of changes in hazards, exposure, and vulnerability at the site and in the surrounding community as a result of this proposal. This discussion should encompass short-and long-term actions that are necessary to ensure that the flood control system remains in optimal operating condition in perpetuity. This points to several risk assessment topics that will need to be addressed more fully in the DEIS. The following is a general statement of such topics. Each topic should be developed with an appropriate level of detail. Other, different risk assessment topics may also be indicated as you address this issue. The topics listed below are descriptive of the kind of risk assessment that the City requests in the DEIS, and are not to be understood as limitations on this subject or as the sole considerations that need to be addressed. • System failure potential -The flood management system described in the DEIS relies on a coordinated set of interrelated systems, which appear to include the following premises: o Floodwaters will be managed, in part, through significant conveyance facilities and infiltration facilities; o Chester Creek flows enter the proposed development from the south; o The floodwater flows will be adequately conveyed through the conveyance facilities around the southern and then eastern side of the proposed development to the proposed drywell gallery at the northeast corner; o There is sediment removal through a bioswale and settling pond; o The drywell gallery will percolate at predicted rates; o The subterranean groundwater mounding at the infiltration facility will have no adverse off-site impacts; o Unnamed tributary flows from the east will be captured in a pipe system and conveyed to an offsite pit which will be widened, deepened, and have drywells installed to infiltrate stormwater; o The overall system of conveyance facilities and drywell galleries will continue to operate at optimal condition in perpetuity without any appreciable change or deterioration in system performance over time and notwithstanding potential changes in circumstances related to external factors such as varying levels of system degradation, impact from extreme weather events, such as snowfall occurrences followed by sudden warming, offsite development activity, or other occurrences. The DEIS should clearly list these (or other applicable) premises and describe them fully. The DEIS should provide references as appropriate to justify their use as planned for this Painted Hills EIS Review Mr. Read Stapleton Sept. 19, 2019 Page 3 proposal. The DEIS should describe potential risks or losses associated with hazards that this system may present, including identifying possible points of failure within the system. These risks should include discussion of potential events (from mild to extreme) within and across given periods of time and specific to place of possible impact. Because the proposed project will purportedly also remove offsite areas from the floodplain, consequences of its removal should also be addressed in conjunction with the risks and losses discussed above. Finally, the hydraulic model materials should be incorporated by reference to the DEIS. • System failure impacts -The DEIS should investigate impacts of system failure, identifying and explaining what will happen if individual components of the system fail to work as planned. The DEIS should also identify recourse for any system failure for each potential point of vulnerability. This discussion should help reviewers assess the probability of types of system failure for different foreseeable events and the adverse consequences of system failure. • Ground water impact-The hydraulic model materials supporting the design of the onsite infiltration system appears to be based upon a single drywell test ( documented in IPEC reports dated June 28, 2016 and August 21, 2017) that is located on the western edge of the infiltration system. Given that the infiltration system is a critical component for the system to work as anticipated, more discussion regarding the use of the single drywell test as the basis for the infiltration and percolation analysis and risks associated with such reliance should be included, or additional tests from within the proposed infiltration system area should be conducted to further support the infiltration and percolation analysis. Additionally, the DEIS should discuss whether modifying the distribution of the onsite infiltration that occurs near Chester Creek will negatively impact groundwater inflows and thus reduce base flows to Chester Creek, as it is designated as a Type F (fishbearing) stream on Washington Department of Natural Resources maps. • Gustin Pit groundwater impact -The offsite "Gustin Pit" had no mounding analysis done to assess downgradient impacts at that site. The DEIS should discuss risks of not conducting an analysis and potential impacts, or alternatively if the applicant conducts the analysis, then it should be incorporated into the DEIS. • System maintenance-The DEIS assigns responsibility for flood control system maintenance and operations to the project's homeowners association. The DEIS should state all expectations for system maintenance and operation. This discussion should identify contingencies for all foreseeable risks in the event that system maintenance and operation is not performed. If the homeowners association becomes insolvent or is poorly equipped or trained to maintain the stormwater management system, describe contingency plans to ensure that risks, including system failure, do not materialize. The DEIS should identify a more fully guaranteed approach to funding and sustaining system maintenance to ensure the system is adequately maintained in perpetuity and that liability Painted Hills EIS Review Mr. Read Stapleton Sept. 19, 2019 Page4 for system maintenance and performance will not fall to the general public or to any governmental agency, including the City of Spokane Valley or Spokane County. Transportation impacts during construction The DEIS provides an estimate of the number of truck trips to manage the export and import of earth and gravel for the proposal, noting that nearly 400,000 cubic yards of material will be moved through the use of approximately 12,500 truck trips. The DEIS averages out the trips across four years of construction, presuming a steady flow of movement every business day of the year. This is unlikely and seems to overlook potential construction-related transportation impacts as well as opportunities to mitigate those impacts. The DEIS should take a more detailed look at truck impacts to the roadway system, to local traffic, identification of the most likely routes of travel, and when fill-related truck transportation is likely to occur along those routes. This analysis should examine variability in trip generation occurrence through the expected duration of construction. Phases of construction, seasonality, and intensity of use of the street system by other users (e.g., school busing schedules, work rush hours), should all be analyzed in conjunction with expected trip generation patterns during project construction. The potential that more intense use of the street system than projected, or that construction-related transportation may take longer than projected, should be discussed. The DEIS should also review axle loads and likely pavement impacts to the surrounding street system, particularly those local access and collector routes relied upon for site access and haul routes, as well as mitigation measures to minimize such pavement impacts. Grading and fill Information about the source of the fill materials should be provided, describing how the proponent will ensure that only clean fill is used. In addition, the discussion of type of fill material should address impacts that large scale importation of different types of fill may have on future development or the operation of the floodwater management system, such as decreased groundwater infiltration due to use of fill that does not provide the same level of infiltration as current soils. Finally, given the extent of necessary fill and estimated time to import the fill, there should also be more detailed discussion of erosion control during the course of importing the fill, including implications of failure of identified erosion control strategies. Multi-family access The proposed access road to the multi-family development site is in the 100-year flood plain. Impacts and possible mitigation measures, such as through alternative alignment, should be considered in the DEIS. Procedure The DEIS should describe the process this project will follow to integrate local project approvals with other agency determinations. Currently, the City believes that submission of the CLOMR application is dependent upon completion of the EIS process and review and approval of other project permits. This process should be discussed, as well as how or whether local approvals for the project would reference FEMA's expected review and action on the CLOMR and subsequent LOMR. The DEIS should describe how the likely range of FEMA actions during the CLO MR Painted Hills EIS Review Mr. Read Stapleton Sept. 19, 2019 Page 5 review may interrelate with the DEIS and the local land use applications and decisions in the event of revisions to the project that may arise during FEMA review. FEMA may provide conditions that could influence the project's design or could inform the City's potential conditions of approval. However, the City is the permitting local agency. The DEIS should explain this relationship, the relative timing of agency actions, and how the outcome ofFEMA's review can influence the applicant's and the City's responses. The possibility of supplemental environmental review, or re-visiting the elements of the project after FEMA review of the CLOMR, should be considered. If the applicant believes a different process may be warranted, it should provide discussion of that analysis, as well as necessary support. Respectfully, J) . (rJJU Lori Barlow, AICP Senior Planner Cc. Bryan Walker, Black Realty Inc. Todd Whipple, Whipple Consulting Engineers John Hohman, Deputy City Manager Henry Allen, PE, Sr. Engineer January 24, 2020 Mr. Read Stapleton, AICP DOWL 720 SW Washington St, Ste 750 Portland, OR 97205 Subject: Draft DEIS Dear Read, Community & Public Works Department 10210 E Sprague Avenue • Spokane Valley WA 99206 Phone: (509) 720-5000 • Fax: (509) 720-5075 • www.spokanevalley.org Email: pcrmitcenter@spokanevallcy.org Thank you again for having the phone call with us on January 23, 2020, to discuss the status of the draft DEIS. Specifically, we appreciate you providing clarification on your client's intent to pursue FEMA review of the CLOMR application concurrently with the EIS process. As we discussed, we understand you are working to address comments on the draft DEIS provided by the City in its letter dated September I 9, 2019. We understand that you intend to provide the CLOMR application to FEMA for review concurrently with the DEIS review process in order to engage with FEMA so that its review input can be considered and incorporated into the EIS. This will allow further development of possible environmental impacts as well as mitigation to further enhance development of the EIS. As we have discussed in prior letters, we look forward to receiving the revised draft of the DEIS so we may issue it and continue the EIS process. We understand you hope to have it ready for submittal before the end of February. If you have any questions, please contact me at (509) 720-5335 or lbarlow@spokanevalley.org. Respectfully, 'rR~ f6awnrJ Lori Barlow, AICP Senior Plmmer Cc: Bryan Walker, Black Realty, Inc. Todd Whipple, Whipple Consulting Engineers Erik Lamb, Deputy City Attorney Ken Harper, Menke Jackson Beyer, LLP, Attorney for City Nathan Smith, Kutak Rock, Attorney for Applicant Page 1 OPERATIONS AND MAINTENANCE PLAN FOR PAINTED HILLS PLANNED RESIDENTIAL DEVELOPMENT FLOOD CONTROL SYSTEM & PLAT AMENITIES Abbreviations PRD – Planned Residential Development HOA – Homeowner’s Association C.E.- Contracted Entity COSV- City of Spokane Valley OHWM- Ordinary High Water Mark AHJ- Agency Having Jurisdiction OSHA- Occupational Safety and Health Administration Owner: Black Realty Inc.; or HOA as created via the Washington Secretary of State. Party(s) responsible for Operations & Maintenance: 1) Black Realty Inc. until the formation of an HOA is complete. 2) Painted Hills PRD Homeowners Assn. 3) Contracted Maintenance Entity 4) Community Oversight – per CFR 65.6(a)(12) the City of Spokane Valley (COSV) Manager or designee, and Spokane County Manager or designee (offsite facilities) will be responsible for assuring that the maintenance activities are accomplished based on the governing jurisdictional boundary. Parent Parcel Number(s)-COSV: 45336.9191, 45334.0106, .0108, .0109, .0110, .0113, .0114, .9135, 44040.9144 LOCATED IN SECTION 33 & 34, T25N, R44E & SECTION 4, T24N, R44E, W.M. SPOKANE COUNTY, WASHINGTON The above parent parcels contain the Painted Hills PRD flood control drainage system. The residential lot owners, commercial property owners and multi-family property owners of Painted Hills PRD, are benefitting from these flood control facilities. The homeowner’s association of this project, which is comprised of residential, multi-family and commercial lot owners, is responsible for (details described later):  The continued operations and maintenance, including repair and replacement as needed, of these facilities, see PRD Flood Control Plans.  Providing funds to finance the continued operation and maintenance of these facilities,  The administration of this agreement with each property owner within the PRD being bound by this agreement and with the responsibilities to be shared equally between each Painted Hills PRD property owner, (see fee schedule for applicable percentages) or contracted entity.  Establishing a maintenance committee and designating an HOA member to be responsible for the administration of this plan,  Providing an annual report each October to Spokane Valley Public Works describing the general status of the sinking fund account, and Page 2  Providing an annual report each October to Spokane Valley Public Works describing specific inspections, findings and maintenance performed, see checklist. This operations and maintenance plan runs with the land and is binding upon the Painted Hills PRD Homeowners Association property owners, their heirs, successors and assigns. The parties mentioned above are primarily responsible for all operations and maintenance of facilities mentioned herein and the administration of this plan. Offsite Parcel Number(s)-County: 45336.9108 (Gustin Ditch), 45343.9052 (Triangle Pond) LOCATED IN SECTION 34, T25N, R44E, W.M. SPOKANE COUNTY, WASHINGTON The above offsite County parcels are also a part of the Painted Hills PRD flood control drainage system. The residential lot owners, commercial property owners and multi-family property owners of Painted Hills PRD, are benefitting from these flood control facilities. The homeowner’s association of this project, which is comprised of residential, multi-family and commercial lot owners, is responsible for (details described later):  The continued operations and maintenance, including repair and replacement as needed, of these facilities, see Gustin Pipe Plan set.  Providing funds to finance the continued operation and maintenance of these facilities,  The administration of this agreement with each property owner within the PRD being bound by this agreement and with the responsibilities to be shared equally between each Painted Hills PRD property owner, (see fee schedule for applicable percentages) or contracted entity.  Establishing a maintenance committee and designating an HOA member to be responsible for the administration of this plan,  Providing an annual report each October to Spokane County Public Works describing the general status of the sinking fund account, and  Providing an annual report each October to Spokane County Public Works describing specific inspections, findings and maintenance performed, see checklist. This operations and maintenance plan runs with the land and is binding upon the Painted Hills PRD Homeowners Association property owners, their heirs, successors and assigns until such time as the Gustin property (Parcel No. 45344.9108) develops and then the owner of that parcel will assume responsibility for this plan. Parcel No. 45343.9052 (triangle pond) is covered by a storm drainage easement granted to Spokane County as recorded in Book 659 Page 1803. Spokane County assumes no responsibility at all for any operations or maintenance of the facilities mentioned herein or the administration of this plan. Spokane County and the City of Spokane Valley and their authorized agents are granted access rights for routine inspection and emergency repairs, but in doing so incur no responsibility to perform these functions at any time. 1.00 PURPOSE This plan is to provide: 1. General operations and maintenance responsibilities for the facilities described herein, and 2. Cost estimates of the assessments to be paid by each property owner mentioned herein for the funding of this maintenance. Page 3 2.00 GENERAL OPERATIONAL CHARACTERISTICS Parent Parcel(s) Drainage Facilities-COSV The Painted Hills PRD flood control drainage and existing Chester Creek system is intended to collect and discharge stormwater runoff generated by upstream basins and stormwater from adjacent properties as is identified on FEMA panel (53063C0751D, effective date July 6, 2010) as compensatory storage or pass through storm flows. The PRD drainage facilities consist of a box culvert under Thorpe Road with a concrete channel, headwall and trash rack, two 48” pipe mainlines between the box culvert and discharge facility with another concrete headwall and trash rack at the outlet, WSDOT catch basins/manholes, a bio-infiltration swale, settling pond with two 48” pipe outlets, headwall and trash rack (upstream, and downstream), and a infiltration field/pond with associated drywells that receives runoff form the settling pond. The system also includes 4-18” cross culverts under Madison Road that connect easterly of to the two 48” pipe mainlines. A portion of stormwater runoff from the upstream basins south of the project flows in the Chester Creek channel under Thorpe Road continuing northwesterly under Dishman-Mica Road. This channel is also a part of the system and will need to be maintained in conjunction with the City of Spokane Valley The remainder of stormwater runoff from upstream basins south of the project flows under Thorpe Road via the PRD box culvert then flows into the pipe system, through the grassed bio-infiltration swale and into settling pond, until discharging into the infiltration pond at the north end of the site where the flow is stored and infiltrated into the ground. Stormwater runoff from upstream basins east of the project flows under Madison Road into 18” culverts and outfalls into the two easterly 48” pipelines via WSDOT catch basins/manholes. It is important to provide adequate maintenance activities to ensure that the flood control facilities remain silt and debris free, as this silt and debris will affect their performance. Additionally, vegetation must be maintained to prevent erosion of the system. Maintenance details are discussed below in Section 3.0. Offsite Parcel(s) Drainage Facilities- County The offsite County triangular pond located to the east of the Painted Hills project site (off of 40th Avenue and west of Hwy. 27) is a part of the Whipple Consulting Engineers (WCE) Gustin Pipe Plan set. This triangular pond and Gustin ditch are part of the County’s existing stormwater and floodplain system. The improvements to this existing County storm system includes the addition of a 36” storm pipe running parallel and within the existing Gustin Ditch, stormwater drywells, and a gravel access/maintenance road to the pond bottom. The existing Gustin Ditch (Parcel No. 45344.9108) is intended to collect and discharge stormwater runoff into the triangle pond (Parcel No. 45343.9052) that is generated by upstream basins and from adjacent properties as is identified on FEMA panel (53063C0751D, effective date July 6, 2010). It is important to provide adequate maintenance activities to ensure that the flood control facilities remain silt and debris free, as this silt and debris will affect their performance. Additionally, vegetation must be maintained to prevent erosion of the system. Maintenance details are discussed below in Section 3.0. Page 4 3.00 MAINTENANCE REQUIREMENTS AND SCHEDULES All inspections and repairs are to be performed by or directly overseen by qualified professionals and personnel (contracted entity) per this schedule and following major events. Maintenance tasks are to be performed soon after the need is identified and before the facility is to perform unless otherwise agreed to by the City or County for offsite drainage facilities. Repairs or replacements are to be completed immediately upon their identification unless otherwise agreed to by the City or County. Only qualified individuals may enter confined spaces and all OSHA rules must be followed. Major repairs or reconstruction will need to be designed, approved, and inspected by professional engineers and the City of Spokane Valley or Spokane County for applicable offsite facilities. Parent Parcel(s) Drainage Facilities-COSV The drainage facilities consist of several elements including: box culverts, existing Chester Creek channel, storm drain mainline, culverts, outlet structure, bio-infiltration swale, inlet structure, infiltration pond and associated drywells, manholes, catch basins, access roads, headwalls with trash racks, fencing, and plant material. These elements are located as shown on the attached exhibit. The following describes these facilities and the minimum required maintenance. A comprehensive visual inspection of the complete PRD flood control drainage facilities should be conducted twice a year. More frequent inspections for various elements may be required as described below. For long duration storms, greater than 24 hours, the drainage facilities should be inspected during the storm event to identify any developing problems and safely correct them before they become major problems. Signs shall be posted notifying all residents to look for “potential” problems and to notify the homeowners’ association of those observations. In general, it is important to provide adequate maintenance activities to ensure that the vegetated areas and structures remain silt, dirt and debris free because accumulations of these will affect the facilities function for stormwater storage volume as well as the ability of the drywells and pond bottom to discharge stormwater. Should these facilities silt up or become clogged, the flood control system will not function as intended putting the PRD at risk of flooding. Therefore, periodic maintenance is a must. Irrigation of Drainage Facilities-COSV The Painted Hills PRD Homeowner’s Association and qualified personnel (contracted entity) shall ensure that all drainage facilities are properly irrigated on a regular schedule to maintain and promote healthy vegetation. Proper irrigation of vegetation is imperative to help to prevent erosion of channels, slopes, and swale and pond bottoms. Personnel shall be careful not to overwater or erosion or excessive saturation may result. This includes the roadside swales and/or landscape strip along Dishman Mica Road, Thorpe Road, and Madison Road. Box Culvert-COSV: There are three box culvert crossings adjoining the project site; two are under Thorpe Road and one is under Dishman Mica Road. These box culverts are within the public road right of way and will be maintained by the agency having jurisdiction (AHJ) of the roadway. Any problems noticed while inspecting or maintaining other elements of the system should be reported to the AHJ. Page 5 LOCATION AGENCY HAVING JURISDICTION (AHJ) Thorpe Rd near Madison Rd-Proposed City of Spokane Valley Thorpe Rd near Dishman-Mica Rd-Existing City of Spokane Valley Dishman-Mica Rd-Existing City of Spokane Valley Chester Creek-COSV: In addition to the instructions listed below, see Appendix B, Chester Creek, Operation & Maintenance Manual from “Geotechnical Evaluation, Levee Evaluation and Certification, 4403 South Dishman-Mica Road, Spokane County, Washington” prepared by Inland Pacific Engineering Company Project No. 14- 037, dated February 12, 2015, Revised August 29, 2016. As part of the project, stream buffer mitigation impact areas are also necessary due to grading operations (fill) within the Chester Creek buffer area. Maintenance of the required buffer mitigation areas are essential to restore and enhance the disturbed riparian areas that provide a natural cover and provide food for native species; this will be accomplished by re-establishing vegetation and by noxious weed control/reduction, and providing adequate irrigation for healthy vegetative growth. For the complete report, including the planting schedule and guidelines for planting and maintaining healthy vegetation in these mitigated areas, see the see the Biological Evaluation, Critical Areas Report, and Habitat Management Plan for Painted Hills completed Larry Dawes of Biology Soil & Water, Inc. provided in the Appendix (dated 02/28/19). It should be noted, that some maintenance items listed below are taken directly from the above-mentioned report; mitigation requirements listed below are also required for a minimum of five years if performance goals are met, or until performance goals are met following the 5-year minimum requirement. The Performance goals are listed in the maintenance items below, and the City of Spokane Valley and Larry Dawes of Biology Soil & Water, Inc (or other professional Biologist) will determine if these goals have been satisfied after 5- years. Annual maintenance of the mitigation areas should still continue after the required performance goals are met, to ensure healthy vegetative growth and provide erosion control; however, the required amount of vegetation and monitoring reports will not be stipulated or required by the City of Spokane Valley. Chester Creek extends across the southwest corner of the site from Thorpe Road northwesterly for approximately 900 feet where it crosses under Dishman-Mica Road. The creek carries seasonal flows from the foothills to the south. The site is protected from flood flows by an existing levee along the northerly side of the creek and along the north side of Dishman-Mica Rd to Wilbur Rd. The intent of the Painted Hills PRD fill project is to fill on the landward (north easterly) side existing levee, which will provide further protection from flooding on the interior landward side of the painted Hills Development. After the project is filled, the creek channel will need to be maintained to ensure flood carrying capacity is not diminished. Maintenance of the channel, up to the Ordinary High Water Mark (OHWM) shall be the responsibility of the City of Spokane Valley, while maintenance above the (OHWM) including obtaining permits to perform the maintenance, shall be the responsibility of the Painted Hills PRD Homeowner’s Association in coordination with the City of Spokane Valley. Maintenance items (above the OHWM) include:  Regular mowing, grass should be kept at 3 inches or more in height but shall not exceed 12 inches, with the last mowing occurring to allow 8-10 inches of growth prior to winter  Removing trash, debris, noxious weeds plus items that reduce the amount of vegetative cover,  Removing any starts of woody vegetation that appear in the channel side slopes. Only native grasses shall be used in the channel, Page 6  Repairing any holes caused by burrowing animals and human activity such as utility work, ORV’s or vandalism on the channel side slopes, traps for burrowing animals shall be used if required,  Inspecting the channel side slopes making sure there are no breaches or breaks or erosion and check for root and tree start invasion. Immediately repair with a sandy loess soil, compacted in place, or bentonite type soil, and follow up after the storm event with seeding or sodding the repair and more substantial maintenance activities if needed,  Repairing mowing damage,  Removing and replacing of the native grass and underlying soil if it becomes degraded to the extent that the grass is not healthy and/or wilted,  Annually inspecting all mitigation areas to ensure re-establishment of vegetation in compliance with the Biological Evaluation Report mentioned above,  Annually Inspecting the mitigation areas for noxious weed in the Spring to determine if the previous year’s weed control measures were adequate, and to make preparations for the current year accordingly,  Filling out the levee checklist and include the checklist in the annual report to the City.  Providing adequate irrigation for all required vegetative growth, especially for the Chester Creek stream buffer mitigation impact areas,  Performance Goal-Ensuring herbaceous vegetations reaches 80% areal cover with native grasses after five years, (year 1=20%, year 2=30%, year 3=50%, & year 5=80%) for buffer mitigation areas,  Performance Goal -Ensuring a 100% survival of tree and shrub plantings and 80% survival every year after for five years until performance goals are met for buffer mitigation areas,  Notifying the City of Spokane Valley (COSV) immediately if any observed functionality of the mitigation areas is failing (unhealthy looking or wilting vegetation), Storm Drain Mainline, Concrete Channel, Headwalls, and Trash Rack, and Outlet Pipes -COSV: The storm drain mainline consists of 5,251 linear feet of 48” pipe from the downstream end of the new box culvert at Thorpe Rd and Madison Rd, running parallel to Madison Rd and ending at the bio- infiltration swale at the north end of the site. The bio-infiltration swale further outlets to the settling pond that discharges to the large infiltration pond through (2)-48” outlet pipes that have concrete headwalls and trash racks on the upstream and downstream side if the outlet pipes. The pipes need to be maintained to prevent sediment and trash build-up in the bio-infiltration swale and the infiltration field/pond and associated drywells. The concrete channel and associated headwalls and trash racks located downstream of the Thorpe Road box culvert also needs to be inspected for physical integrity to prevent a breach/leak in the channel or headwall and to ensure no obstructions are blocking the passage for stormwater, and to prevent unauthorized entry into the storm system. Maintenance of the storm drain mainline shall be the responsibility of the Painted Hills PRD Homeowner’s Association and/or the contracted entity (C.E.). Maintenance items include:  Annually inspecting the pipe openings on each end to ensure there is no blockage or damage to the ends,  Every three years or after substantial storm runoff, performing a TV inspection of the pipe looking for blockages, damage, etc., visual inspection can be made at pipe manhole locations by authorized maintenance personnel,  Removing sediment build-up from the pipe,  Repairing any sections of damaged pipe,  Visually inspecting twice a year the concrete channel, headwalls, and trash racks for damage or Page 7 corrosion that would compromise the trash rack integrity.  Prior to each rainy season (August or September), inspecting each trash racks ensuring that there is no debris present,  Following large storm events or rapid snow melt events performing a visual inspection and remove any deleterious debris and trash,  Instructing those performing other maintenance functions on the system to report any observed damage to the trash rack. Catch Basins-COSV: The mainline pipe system has WSDOT Type II catch basins at pipe junctions and angle points. Along Madison Road there are catch basins connected by pipe to the mainline pipe system to drain overflow from the roadside swales. Catch basins need to be maintained to prevent blockage of flow within the system. Contact a professional or have the contracted entity remove the debris, trash and sediment buildup, such as AAA Sweeping LLC. HOMEOWNERS ARE NOT TO ENTER THE MANHOLES/CATCH BASINS. Maintenance of the catch basins shall be the responsibility of the Painted Hills PRD Homeowner’s Association or the C.E. Maintenance items include:  During routine landscape maintenance of roadside swales, removing any debris from catch basin grates,  Annually inspecting catch basins for trash and sediment build-up and removing trash,  When sediment build-up fills ½ the depth of the sump (about 1 foot), removing the sediment,  Annually inspecting catch basin grates and lids to ensure they are properly seated and are structurally sound,  Every five years, inspecting the structure walls to ensure the concrete walls are in good condition and the joints remain sealed,  Instructing those performing other maintenance functions on the system to report any missing lids or grates. Cross Culverts (Flap Gates)-COSV: The cross culverts consist of 18” CMP pipe crossing under Madison Road flowing from east to west in four locations. The culverts connect into WSDOT Type II catch basins on the 48” storm drain mainline. The cross culverts need to be maintained to prevent the reduction of seasonal flows within the pipes. The reduction in flow may be caused by sediment or trash build-up within the pipe or obstruction of the pipe entrance on the east side of Madison Rd. Maintenance of the cross culverts from the inlet up to, but not including the flap gates shall be the responsibility the City of Spokane Valley. However, the flap gates shall be the responsibility of the of the Painted Hills PRD Homeowner’s Association or the C.E. Maintenance items include:  Annually inspecting the flap gates to ensure proper operation,  Every three years performing a TV inspection of the flap gates looking for blockages, damage, corrosion, etc., and notifying the City of Spokane Valley if the pipes themselves need maintenance,  Removing sediment build-up from the flap gates,  Repairing any sections or components of the flap gates. Page 8 Bio-infiltration Swale/Channel, Roadside Swales, and Settling Pond-COSV: The bio-infiltration swale/channel consists of a grass lined channel approximately 320 feet long with a 6- foot bottom width and 2:1 side slopes and approximately 6-feet in depth. The swale needs to be maintained to perform the function of removing any remaining contaminants including fugitive silts prior to storm water entering the infiltration pond, with adequate irrigation provided for vegetation establishment. Following the bio-infiltration channel is a settling pond to further reduce the sediment loading in the infiltration pond. The settling pond then discharges to the large infiltration pond through (2)-48” outlet pipes with headwalls and trash racks (see the Stormdrain Mainline Section on page 6 of this report for inclusion of the outlet pipes, headwalls and trash racks). Additionally, roadside swales along Dishman Mica Road, Thorpe Road, and Madison Road, require similar maintenance as the bio-infiltration swale/channel that includes removing any sediment buildup or debris from the swales, and adequately irrigating the swale to promote a heathy growth of grass. Maintenance of the bio-infiltration swale, roadside swales, and settling pond shall be the responsibility of the Painted Hills PRD Homeowner’s Association or the C.E. Maintenance items include:  Annually inspecting the bio-infiltration swale/channel bottom and side slopes to ensure there is a covering of grass, grass can be mowed no shorter than 8 to 10 inches, once annually,  Annually inspecting the settling pond bottom and side slopes to ensure there is a covering of grass, grass can be mowed no shorter than 8 to 10 inches,  Removing accumulations of sediment that bury the grass cover for the channel, swales, and pond,  Reseeding any bare or dead areas of grass for the channel, swales, and pond,  Removing any noxious weeds within the channel, swales, and pond (spraying is acceptable),  Providing adequate irrigation for the bio-infiltration channel, swale, and pond (including side slopes),  Annually inspecting the roadside swale bottoms and side slopes to ensure there is a covering of grass, grass should be mowed in the same manner as residential home yards Infiltration Field/Pond and Associated Drywells-COSV: As previously mentioned, the infiltration pond receives runoff from the settling pond through (2)-48” outlet pipes. The infiltration pond is comprised of 48-double depth drywells, and the drywells need to be maintained to prevent or reduce sediment buildup in the drywell barrel so as to not reduce infiltration into the surrounding ground. The infiltration field/pond bottom also needs to remain free of debris and sediment build-up as it is the first point of infiltration. The Maintenance of the drywells and infiltration pond shall be the responsibility of the Painted Hills PRD Homeowner’s Association or the C.E. Maintenance items include:  Visually inspecting twice a year the inside of the drywell barrel(s) by removing the grate to look into the structure. Have all debris and trash removed. Sediment must be removed before buildup reaches the bottom of the lowest slot out of the drywell in the barrel wall. Contact a professional to remove the debris, trash and sediment buildup. HOMEOWNERS ARE NOT TO ENTER THE DRYWELL, as these drywells are 12-feet in depth with no internal ladder system.  Removing accumulations of sediment that bury the grass cover, Page 9 Fencing-COSV: The fencing of various system elements needs to be maintained to restrict access to those elements and to protect the public. Maintenance of the fencing shall be the responsibility of the Painted Hills PRD Homeowner’s Association or the C.E. Maintenance items include:  Visually inspect twice a year the entire fencing system for damaged fence fabric, posts, gates, signs, etc.  Prior to each rainy season (August or September), inspecting each access point ensuring that locks and gates are functional.  Instructing those performing other maintenance functions on the system to report any observed breaches or damage to the fencing. Access Roads/Parking Pads-COSV: The access roads/parking pads to various system elements need to be maintained to allow maintenance vehicles access to those elements for periodic maintenance and emergency repairs to protect the public. Maintenance of the access roads/parking pads shall be the responsibility of the Painted Hills PRD Homeowner’s Association or the C.E. Maintenance items include:  Visually inspecting annually, the entire access road/parking pad system for rutting, potholes, etc. Regrade and repair with additional aggregate as needed.  Removing vegetation from the aggregate surface.  Instructing those performing other maintenance functions on the system to report any observed damage to the access roads/parking pads. Interior Asphalt Pathway, exterior Asphalt Pathway, and Concrete Sidewalk-COSV: The interior asphalt pathway, the exterior asphalt pathway (Madison Road & Dishman Mica Road), and concrete sidewalk (Dishman Mica Road & Thorpe Road) that provide pedestrian access around and through the project site need to be maintained to allow safe pedestrian travel. Maintenance of the asphalt pathways and concrete sidewalk shall be the responsibility of the Painted Hills PRD Homeowner’s Association or the C.E. Maintenance items include:  Visually inspecting annually, the entire pathway and sidewalk for rutting, potholes, cracking of concrete or tree root intrusion, and repair or replace with additional asphalt or concrete as needed.  Removing vegetation or debris from the surface.  Instructing those performing other maintenance functions on the system to report any observed damage to the asphalt pathway or concrete sidewalk. Offsite Parcel(s) Drainage Facilities-County The existing Gustin Ditch (Parcel No. 45344.9108) is intended to collect and discharge stormwater runoff into the triangle pond (Parcel No. 45343.9052) that is generated by upstream basins and stormwater from adjacent properties as is identified on FEMA panel (53063C0751D, effective date July 6, 2010). Currently, stormwater runoff from the upstream basins is routed under Hwy 27 through a 36” culvert into Page 10 the Gustin Ditch where the storm water flows to the west to the exiting pond. The improved drainage system will consist of a 36” conveyance pipe running parallel and within the existing Gustin Ditch (Parcel No. 45344.9108) to intercept the upstream basin stormwater. This existing flow will continue to discharge to the existing triangle pond (Parcel No. 45343.9052) through the 36” storm outlet pipe. The triangle pond will also have 18- stormwater drywells and a gravel road installed to provide access for maintenance to the pond and stormwater drywells. These existing flows normally infiltrate into the existing pond bottom, however, during larger storms the stormwater will overflow into the drywells and infiltrate into the ground. The additional stormwater capacity provided by the drywells will capture and eliminate the existing FEMA designated 100-Year Storm Event that would have theoretically continue to West if these drywells were not installed. A visual inspection of the drainage facilities should be conducted twice a year. For long duration storms, greater than 24 hours, the drainage facilities should be inspected during the storm event to identify any developing problems and safely correct them before they become major problems. It is important to provide adequate maintenance activities to ensure that the drainage facilities remain silt and dirt free, as this silt and dirt will affect their performance. Additionally, vegetation must be maintained to prevent erosion of ditch and/or pond sides and to prevent flow restrictions within the ditch and/or pond from the build-up of dead vegetation and tree and shrub invasion. Maintenance details are further discussed below. Gustin Ditch with Pipe and Catch Basins-County: The 36” PVC pipe needs to be maintained to ensure there is no debris or vegetation blocking the flow of stormwater through the pipe. The pipe mainline has two 12” PVC cross culverts near the end of the pipe mainline to further capture runoff from overland flow from the Gustin Ditch Property (Parcel No. 45344.9108). The ditch needs to be maintained to ensure a strong, healthy, dense vegetative cover and that it is free of debris. Maintenance of the ditch and outfall shall be the responsibility of the Painted Hills PRD Homeowner’s Association until such time as the Gustin property (Parcel No. 45344.9108) is developed. At that time the owner(s) of the new development shall assume responsibility for maintenance of the ditch and levee. Maintenance items include:  Regular mowing, grass should be kept at 3 inches or more in height but shall not exceed 12 inches, with the last mowing occurring to allow 8-10 inches of growth prior to winter,  Removing trash, debris, noxious weeds plus items that reduce the amount of vegetative cover,  Removing any starts of woody vegetation that appear in the ditch. Only native grasses shall be used to repair at removal areas,  Repairing any holes caused by burrowing animals and human activity such as utility work, ORV’s or vandalism on the ditch side slopes,  Inspecting the ditch side slopes, and bottom making sure there are no breaches or breaks or erosion and check for root and tree start invasion. Immediately repair with a sandy loess soil, compacted in place and follow up after the storm event with seeding of the repair with native grasses and more substantial maintenance activities if needed,  Repairing mowing damage,  Removal and replacement of the grass and underlying soil if it becomes contaminated to the extent that the grass is not healthy.  Annually inspecting the pipe openings on each end to ensure there is no blockage or damage to the ends,  Every three years or after substantial storm runoff, performing a TV inspection of the pipe(s) looking for blockages, damage, etc., visual inspection can be made at pipe manhole locations by Page 11 authorized maintenance personnel,  Removing sediment build-up from the pipe,  Repairing any sections of damaged pipe. Catch Basins-County: The Gustin Ditch pipe system has County Manholes (48” and 72” diameter) at pipe junctions and angle points. Catch basins need to be maintained to prevent blockage of flow within the system. Contact a professional or have the contracted entity remove the debris, trash and sediment buildup, such as AAA Sweeping LLC. HOMEOWNERS ARE NOT TO ENTER THE MANHOLES/CATCH BASINS. Maintenance of the catch basins shall be the responsibility of the Painted Hills PRD Homeowner’s Association or the C.E. Maintenance items include:  During routine landscape maintenance of roadside swales, removing any debris from catch basin grates,  Annually inspecting catch basins for trash and sediment build-up and removing trash,  When sediment build-up fills ½ the depth of the sump (about 1 foot), removing the sediment,  Annually inspecting catch basin grates and lids to ensure they are properly seated and are structurally sound,  Every five years, inspecting the structure walls to ensure the concrete walls are in good condition and the joints remain sealed,  Instructing those performing other maintenance functions on the system to report any missing lids or grates. Triangle Pond & Drywells-County: The pond bottom needs to be maintained to ensure there is no debris, vegetation or sediment preventing the infiltration of storm water through the bottom of the non-irrigated pond. Also, that no debris, vegetation or sediment buildup rise to a level that would allow it to enter into the drywells. Drywells need to be maintained to prevent or reduce sediment buildup in the drywell barrel that would reduce infiltration into the surrounding ground. Maintenance of the pond and drywells shall be the responsibility of the Painted Hills PRD Homeowner’s Association until such time as the Gustin property (Parcel No. 45344.9108) is developed. At that time the owner(s) of the new development shall assume responsibility for maintenance. Maintenance items include:  Periodically visually inspect the grate and remove any deleterious debris and trash.  Biennially visually inspect the inside of the drywell barrel(s) by removing the grate to look into the structure. Have all debris and trash removed. Sediment must be removed before buildup reaches the bottom of the lowest slot out of the drywell in the barrel wall. Contact a professional to vacuum out the debris, trash and sediment buildup. HOMEOWNERS ARE NOT TO ENTER THE DRYWELLS. Fencing-County: The fencing around the triangle pond needs to be maintained to restrict access to those elements and to protect the public. Maintenance of the fencing shall be the responsibility of the Painted Hills PRD Homeowner’s Association or the C.E. Page 12 Maintenance items include:  Visually inspect twice a year the entire fencing system for damaged fence fabric, posts, gates, signs, etc.  Prior to each rainy season (August or September), inspecting each access point ensuring that locks and gates are functional.  Instructing those performing other maintenance functions on the system to report any observed breaches or damage to the fencing. Access Roads/Parking Pads-County: The access roads/parking pads to the triangle pond need to be maintained to allow maintenance vehicles access to those elements for periodic maintenance and emergency repairs to protect the public. Maintenance of the access roads/parking pads shall be the responsibility of the Painted Hills PRD Homeowner’s Association or the C.E. Maintenance items include:  Visually inspecting annually, the entire access road/parking pad system for rutting, potholes, etc. Regrade and repair with additional aggregate as needed.  Removing vegetation from the aggregate surface.  Instructing those performing other maintenance functions on the system to report any observed damage to the access roads/parking pads. 4.00 SINKING FUNDS A sinking fund is an account that is set up to receive regular deposits which are to be used for paying off future costs and debts. The sinking fund monies will be used to pay for planned and unplanned operation and maintenance costs along with certain future replacement costs for the storm drainage facilities. The sinking fund calculation should be revised as necessary to account for actual expenses and changes in rates. In setting up the fund, first the future replacement costs are estimated and then they are converted to annual costs (or deposits) by the following calculations. These calculations assume that the inflation rate is 3% (for estimating the future replacement costs), the typical interest rate is 2% (for estimating the annual costs) and the number of years before replacement is 20 (expect for buffer mitigation area replacement. Equations and guidance for using other rates and years can be found in Appendix A. 1) Estimate the value that the item will have in the future when it is time to replace it using the following equation: FV=PV*1.8061, where: FV = future value PV = present value 2) Estimate how much money will need to be deposited each year in a bank account in order to have enough money accumulated in time to pay for the replacement using the following equation. A=FV*0.0412, where: A = annual payment (or deposit) FV = future value (from step 1, above) Page 13 Sinking Fund Calculation Results: The developer shall provide $95,000 to initiate the set-up of maintenance funds, and provide for one year of maintenance. The following values are the results of the calculations which are shown on the following page. The fund calculations shall be updated once the actual cost of operation and maintenance items are contracted. As contracts are renewed, the costs shall be adjusted accordingly. Annual cost for regular operation and maintenance $152,392 Annual cost for replacements $76,979 Total annual costs $229,370 Total monthly costs (= total annual costs /12)$19,114.18 *Number of units (SF lots +MF lots) +(Commercial) 596+(18,400sf/100SF)=615 Monthly cost per lot (= total monthly costs /# lots)$31.08 Total annual cost per lot/unit $372.96 *Note: Number of units is based on 255-single family lots, 49 cottage units/lots, 240 apartment units, 52 mixed use apartment units, and 18,400 square feet of commercial building area divided by 1,000 square feet (for an equivalent unit/lot). Page 14 Sinking Fund Calculations-Parent Parcel(s)-COSVUnit Annual Price = CostComprehensive System InspectionEA2$1,000 $2,000 Drywell CleaningEA48 $500 $24,000 Catch Basin CleaningEA23 $300 $6,900 Mowing Channel EmbankmentsEA4 $2,000 $8,000 Mowing Roadside SwalesEA4 $2,000 $8,000 Debris Removal – culverts, catch basins, bio-swale, channels, drywells, manholesEA4 $2,000 $8,000 Channel/Trash Rack InspectionEA9 $500 $4,500 Pipeline TV Inspection – mainline, culverts, (3 years)LF5,750 $3 $17,250 Manhole/Catch Basin InspectionEA23 $100 $2,300 Fence, Access Road, Parking Area, Sign MaintenanceEA1 $500 $500 Swale & Pond Reseeding/Noxious Weed RemovalEA1 $500 $500 Reseeding/Noxious Weed Removal for buffer mitigation area EA1 $5,000 $5,000 1st Year Monitoring Report + ASBUILT ReportLS 1 $6,500 $6,500 Annual Monitoring Report (after 1st year)LS 1 $1,000 $1,000 Annual Report PreparationEA1 $1,500 $1,500 ContingencyLS1 20% $19,190 Total $115,140 REGULAR OPERATION AND MAINTENANCE COSTS-COSVDescriptionUnitsAnnual Quantity x Page 15 UnitPrice =Drywell (48) (25%)EA 12 $10,000 $120,000 20 0.03 $216,733 0.02 $8,920 48” ADS N-12 HDPE pipeline (5,251) (25%) LF 1313 $150 $196,913 20 0.03 $355,646 0.02 $14,637 48” ADS N-12 HDPE culvert pipes (120 LF) (100%)LF 120 $150 $18,000 20 0.03 $32,510 0.02 $1,338 24” CMP pipeline (136) (100%)LF 136 $70 $9,520 20 0.03 $17,194 0.02 $708 18” PS46 ASTM F679 PVC (pipeline-future) (40) (100%)LF 40 $40 $1,600 20 0.03 $2,890 0.02 $119 15” Perforated HDPE (underdrain) (40) (100%) LF 40 $30 $1,200 20 0.03 $2,167 0.02 $89 12” SDR-35 ASTM D3034 PVC pipe to mainline(44) LF 44 $24 $1,056 20 0.03 $1,907 0.02 $78 12” CMP pipe to outfall (119) (100%)LF 119 $30 $3,570 20 0.03 $6,448 0.02 $265 WSDOT Catch basin, Type II (12)EA2 $4,500 $9,000 20 0.03 $16,255 0.02 $669 Catch basin, Type I (12)EA2 $1,500 $3,000 20 0.03 $5,418 0.02 $223 Infiltration & Settling Pond -seeding (189,644+7,172 )+ Roadsides Swale Seeding (49,187 ) + Landscape Strip Seeding (2,471 )SF 248474 $0.10 $24,847 20 0.03 $44,877 0.02 $1,847 Trash Racks (8) (100%)EA8 $2,000 $16,000 20 0.03 $28,898 0.02 $1,189 Signs (4) (25%)EA1 $200 $200 20 0.03 $361 0.02 $15 Buffer Mitigation Area (25%) of total cost of VegetationLS5 $6,785 $33,925 5 0.03 $39,328 0.02 $7,557 2” Asphalt pathway (9702 LF interor + 2,482 LF Madision Rd+ 822 LF Dishm. Rd)SY 14501 $10 $145,013 20 0.03 $261,910 0.02 $10,779 6” CSTC Access Rd (1,113 LF) (25%)CY 2087 $40 $83,480 20 0.03 $150,774 0.02 $6,205 Fencing (132 LF)LF 132 $35 $4,620 20 0.03 $8,344 0.02 $343 PC Concrete Sidewalk (Dishm.-356 LF+ 1356 LF Thorpe)SY 991 $36 $35,664 20 0.03 $64,413 0.02 $2,651 Total $57,635 REPLACEMENT COSTS-Parent Parcel(s)-COSV(for more information on calculations in this table see Appendix A)UnitsQuantity x Present Value, PVnInflation Rate, i1Future Value, FVInterest Rate, i2Annual Payment, A Notes: n = number of years to replacement LS means Lump Sum, EA means Each, SY means square yard, LF means Linear Feet, CY means Cubic Yards Quantity x is based on either a complete replacement (100%) or assumed 25% of the total rounded to the nearest whole number Page 16 Sinking Fund Calculations-Offsite Parcel(s)-County Unit Annual Price = CostComprehensive System InspectionEA2$500 $1,000 Drywell CleaningEA 18 $500 $9,000 Manhole CleaningEA 9 $300 $2,700 Mowing Ditch EmbankmentsEA 4 $2,000 $8,000 Debris Removal – culverts, catch basins, pond ditch, drywells, manholesPipeline TV Inspection – mainline, culvertsLF 1,481 $3 $4,443 Manhole InspectionEA 9 $100 $900 Fence, Access Road, Parking Area, Sign MaintenanceEA 1 $500 $500 Pond Reseeding/Noxious Weed RemovalEA 1 $500 $500 ContingencyLS 1 20% $6,209 Total $37,252 EA 4 $1,000 $4,000 REGULAR OPERATION AND MAINTENANCE COSTS-COUNTYDescriptionUnitsAnnual Quantity x Page 17 UnitPrice =Drywell (12) (25%)EA 12 $10,000 $120,000 20 0.03 $216,733 0.02 $8,920 36” PS46 ASTM F679 PVC pipeline (1441) (25%) LF 361 $150 $54,150 20 0.03 $97,801 0.02 $4,025 12” SDR-35 ASTM D3034 PVC pipeline (136) (100%)LF 136 $70 $9,520 20 0.03 $17,194 0.02 $708 Type I -48-County ManholeEA 2 $4,500 $9,000 20 0.03 $16,255 0.02 $669 72" County ManholeEA 5 $7,500 $37,500 20 0.03 $67,729 0.02 $2,788 Triangle Pond-seeding (17,060 SF) (100%)SF 17060 $0.10 $1,706 20 0.03 $3,081 0.02 $127 Signs (4) (25%)EA1 $200 $200 20 0.03 $361 0.02 $15 6” CSTC Access Rd (770 LF) (25%)CY 214 $40 $8,556 20 0.03 $15,452 0.02 $636 Fencing (560 LF) (100%)LF 560 $35 $19,600 20 0.03 $35,400 0.02 $1,457 Total $19,344 REPLACEMENT COSTS Offsite Parcel(s)-County (for more information on calculations in this table see Appendix A)UnitsQuantity x Present Value, PVnInflation Rate, i1Future Value, FVInterest Rate, i2Annual Payment, A Page 18 IN WITNESS WHEREOF, the undersigned has reviewed the above information and determined it to be appropriate for the improvements proposed for this plan and has caused this instrument to be executed on this day of __________________________, 20____. Signature: Name (print): Title: STATE OF WASHINGTON ) COUNTY OF SPOKANE ) CITY OF SPOKANE VALLEY ) ss I certify that I know or have satisfactory evidence that is/are the individual(s) who personally appeared before me, and who acknowledged that he/she/they executed and signed this instrument and acknowledged it to be his/her/their free and voluntary act for the uses and purposes mentioned in this instrument. Dated this __________ date of ______________________, 20____. NOTARY PUBLIC In and for the State of Washington, Residing at My appointment expires: Page 19 Appendix A The future replacement costs can be estimated and then converted to annual costs (or deposits) by the following calculations. 1) Estimate the value that the item will have in the future when it is time to replace it using an assumed (best estimate) inflation rate and the following equation: FV=PV*(1+i1)n , where: FV = future value i1 = inflation rate PV = present value n = number of years to replacement Example values for the factor: (1+i)n n, years 5 10 15 20 i1 0.02 1.1041 1.2190 1.3459 1.4859 0.03 1.1593 1.3439 1.5580 1.8061 0.04 1.2167 1.4802 1.8009 2.1911 0.05 1.2763 1.6289 2.0789 2.6533 2) Estimate how much money will need to be deposited each year in a bank account in order to have enough money accumulated in time to pay for the replacement using an assumed (best estimate) interest rate and the following equation: A=FV* i2 / [(1+i2)n-1], where: A = annual payment i2 = interest rate FV = future value n = number of years to replacement Example values for the factor: i2/[(1+i2)n-1] n, years 5 10 15 20 i2 0.02 0.1922 0.0913 0.0578 0.0412 0.03 0.1884 0.0872 0.0538 0.0372 0.04 0.1846 0.0833 0.0499 0.0336 0.05 0.1810 0.0795 0.0463 0.0302 Page 20 Appendix B – Chester Creek Channel, Operation & Maintenance Manual Modified from “Geotechnical Evaluation, Levee Evaluation and Certification, 4403 South Dishman-Mica Road, Spokane County, Washington” prepared by Inland Pacific Engineering Company Project No. 14-037, dated February 12, 2015, Revised August 29, 2016. Page 21 CHESTER CREEK CHANNEL ABOVE THE ORDINARY HIGH WATER MARK OPERATION & MAINTENANCE MANUAL FOR OPERATION AND MAINTENANCE Painted Hills PRD Homeowners Association IPEC Project No. 14-037 WCE Project # 13-1166 Updated January 2020 By Inland Pacific Engineering Company 3012 North Sullivan Road Building S-5, Suite C Spokane Valley, WA 99216 & Whipple Consulting Engineers 21 S Pines Road Spokane Valley, WA 99206 Page 22 1.00 PURPOSE This Operations and Maintenance manual is intended to provide general operations and maintenance guidelines for the Chester Creek channel located at 4403 South Dishman-Mica Road in Spokane County, Washington. The intent of the Painted Hills PRD project is to fill on the landward (north easterly) side existing levee, which will provide further protection from flooding on the interior landward side of the painted Hills Development. This O & M has been amended from the original Chester Creek Levee O & M provided by Inland Pacific Engineering Company. After the project is filled, the creek channel will need to be maintained to ensure flood carrying capacity is maintained. Maintenance of the channel, up to the Ordinary High Water Mark (OHWM) shall be the responsibility of the City of Spokane Valley. Maintenance above the (OHWM) including obtaining permits to perform the maintenance, shall be the responsibility of the Painted Hills PRD Homeowner’s Association in coordination with the City of Spokane Valley. This general maintenance for the Chester Creek channel is inclusive whether in or out of Spokane County public road rights-of-ways. Implementation of these guidelines will ensure that the channel’s flood carrying capacity is maintained. 2.00 INTRODUCTION The east side of the channel is typically at a 2.3:1 to 3:1 (H:V) slope. The land side of the channel is also at a 3:1 slope from the Dishman-Mica Road bridge to approximately 300 feet southeast. Between this point and Thorpe Road, the land side slope is much less and, in some areas, relatively level with the crest. As mentioned above, the intent of the Painted Hills PRD project is to fill on the landward (north easterly) side existing levee. This existing levee was constructed by the previous landowner for the development of the golf course on the property and we believe it was constructed in the early 1990’s by the property owner. 3.00 GENERAL OPERATION AND MAINTENANCE 3.10 Operation – During flood periods, the creek channel side slopes above the (OHWM) should be patrolled to locate possible sand boils, unusual wetness of the landward slope, or breaches. The inspector may look for indications of sliding or sloughing, that scouring action is not occurring, that the channel is not being overtopped, and that no other conditions exist that might adversely affect the integrity of the channel side slopes. Any damage or observed issues below the (OHWM) should be reported to the City of Spokane Valley immediately.  Boils – A boil is a condition where enough pressure is produced by high water levels so that water is piped through or under the channel bottom and channel side slopes with sufficient velocity to carry earthen materials to the landward side of the channel. If not controlled, these particles of earthen materials will be eroded from within the channel, causing subsidence to the channel section. The continuation of this process Page 23 may result in a break in the channel side slopes, allowing flood waters to flow over the crest or through the channel side slopes.  Scour – Careful observation should be made of the creek channel side slopes to detect potential erosion due to current action. Careful observation at the locations of bridge structures should be made. In general, current velocities in Chester Creek are not expected to cause significant scouring.  Creek Channel Topping – If the anticipated high-water level will exceeds the top elevation of the channel , steps should be taken to provide emergency topping to raise the channel side slope above forecasted water levels. These steps could include sandbagging or hauling additional fill to raise the channel wall height. 3.11 A post-flood assessment of the creek channel side slopes above the (OHWM) should be completed within 24 hours of the event. The assessment should document any damage to the channel caused by flood waters. Any repairs necessary should then be completed after review and evaluation of options. Any damage or observed issues below the (OHWM) should be reported to the City of Spokane Valley immediately. 3.20 Maintenance – Maintenance activities for the creek channel above the (OHWM) are described in this section. Below is a maintenance description for each of the elements affecting channel conveyance performance.  Inspections – channel inspection should include a visual inspection of the channel channel side slope sat a minimum of every 12 months for signs of erosion or settlement. Preferably, the inspection should be completed in the fall prior to the rainy season. The inspections should include the following: o Unusual settlement, sloughing, or material loss of grade. o Caving on both the creekside and landside of the channel which might affect stability of the channel section. o Seepage or saturated areas that may be occurring. o Drainage in the creek is in good working condition facilities are not being clogged. o That the channel is shaped to drain properly to onsite Painted Hills PRD drainage facilities. o Ensuring that no unauthorized vehicles are located on the channel bottom and channel side slopes. o Rodent damage along the channel side slopes.  Erosion Protection – The channel side slope vegetation is a grass cover. The grass should be mowed to a minimum height no shorter than 8 inches. Page 24 No trees should be growing on the creek channel bottom or side slopes. No excavations, structures, or other obstructions should be on the creek channel bottom or side slopes. Remove accumulation of drift, grass clippings, or other objectionable materials from the creek channel side slopes. Attached is a checklist for the annual or post-flood inspection. Page 25 CHESTER CREEK CHANNEL 4403 SOUTH DISHMAN-MICA ROAD SPOKANE COUNTY, WA CREEK CHANNEL CHECKLIST (ABOVE THE OHWM ONLY) Date: _______________________________________________________ Item Location and Description Action Has the creek channel side slopes settled or lost cross section? Has stream action caused any slope washing or scouring? Has there been any seepage or saturated areas? Has vegetation been maintained? Have weeds been removed? Dates? Condition of any riprap? Have there been any authorized or unauthorized encroachments? Have burrowing animals been exterminated/removed and the creek channel channel side slopes repaired? Is the creek channel free of obstructions and/or debris? Are there any areas where the creek is affecting the channel side slopes? Has there been any recent high-water events? Miscellaneous conditions: Note: Use additional sheets as necessary. Signed: Title: Page 26 Appendix C – Letter of Map Revision (LOMR) To be inserted once completed. WESNCSITE ELEMENT PLANC1.3JPP 1" = 200'N/AXDISHMAN-MICA RD.SPOKANE VALLEY,WADRAWN:PROJ #:REVIEWED:DATE:DATUM: NAVD - 8813-1166JOB NUMBERSHEETTRW13-116604/20/20WCETBM S-5 OF THE SOUTH PONDEROSA SEWER PROJECTWITH AN ELEVATION OF 2005.87 (NAVD29)=2009.67(NAVD88) WAS USED FOR THE VERTICAL DATUM FOR THISMAP.WHIPPLE CONSULTING ENGINEERS2528 NORTH SULLIVAN ROADSPOKANE VALLEY, WA 99216PH: 509-893-2617 FAX: 509-926-0227CIVILSTRUCTURALSURVEYINGTRAFFICPLANNINGLANDSCAPEOTHER SPOKANE VALLEY PAINTED HILLS PRDVERTICAL:HORIZONTAL:SCALE:REVISIONSNO. DATE BY 08-12-16JPP ORIGINAL PREPARATION1Reviewed for Conformance toStreet Standards andAccepted per Chapter 1.2Not ReviewedDate AcceptedAcceptance CommentsCity of Spokane ValleyDevelopment EngineeringCity of Spokane ValleyProject/Permit No.:SUB-2015-0001(Subdivision)FPD-2016-0007(Flood Plain Development)EGR-2016-0066(Engineered Grading)08-14-18JPP REVISED PLANS201-03-20JMH REVISED PLANS3DISHMAN-MICA ROADTHORPE ROADMADISON ROAD 40TH AVENUEHIGHWAY 27 WILBER ROAD MADISON RD EASEMENT PLAN- April 21st, 2020 WCE No. 2013-1166 City of Spokane Valley 1 0210 E. Sprague Ave, Spokane Valley, WA 99206 Attn: Henry Allen dWCE Whipple Consulting Engineers, Inc. Re: Painted Hills PRD O & M Manual Precursory review comments Dear Mr. Allen: We have received your email on February 71\ 2020 and offer the following response. For clarity your comments are listed below with our response in Bold. Plan sheet Cl .3 I was looking at plan sheet Cl.3 and noted that there are some design items that will need O&M that need to be included (in the description, tasks, schedules and costs): I. Dishman-Mica Road: the planting strip, sidewalk, roadside swale and path A separate paragraph was added under section 3.00, page 9 (Interior Asphalt Pathway, Exterior Asphalt pathway, and Concrete sidewalk). The plating strip \'\-·as added to the Bio-infiltration Swale/Channel paragraph on page 8. 2. Stream buffer impact mitigation area: Per the biological evaluation, critical areas report and habitat management plan ( especially sections 8, 9 and 10), please include tasks and funding for the maintenance of the items utilized for the mitigation of buffer impacts on Chester Creek. Items include noxious weed monitoring and control (perpetual?); signage maintenance; maintenance of irrigation for plant establishment; annual monitoring with reporting; annual mortality replacement of grasses, shrubs and trees; measures implemented for at least 5 years and until performance objectives are met. Please see the Chester Creek paragraph on page 5 for incorporation of these items. 3. Thorpe Road: roadside swale and sidewalk A separate paragraph was added under section 3.00, page 9 (Interior Asphalt Pathway, Exterior Asphalt pathway, and Concrete sidewalk). The roadside swales were added to the Bio-infiltration Swale/Channel paragraph on page 8. 4. Madison Road: the roadside swa]e, planting area and path Please see response to comment #1 above 2i South Pines Rd. • Spokane Valley, WA 99206 A PO Box i 566 • Veradale, WA 99037 Phone 509-893-2617 • Fax 509-926-0227 • WhippleCE.com • lnfo@WhippleCE.com Civil, Structural, Traffic, Survey, Landscape Architecture and Entitlements Response to Comments City of Spokane Valley April 21, 2020 Page 2 of5 5. Triangle Pond and Gustin Pipe a. Include the O&M for the Triangle Pond items (access road, ground cover, sedimentation, drywells, etc.) and Gustin Pipe facilities that the proponent/HOA will be responsible for; confirm with Spokane County on the tasks and costs. b. Confirm with the County that there are easements in place allowing people the ability to access and work in the pond and on the pipe. These were added on pages 9 and 10 under Offsite Parent Parcel(s) Drainage Facilities (County) section. An easement exhibit and legal will be forthcoming that will allow for County access and performing work as necessary. O&MManual 1. Page 1 a. Abbreviations: include CE and AHJ Added as requested. b. Suggest removing paragraph starting with "Responsible Official" and, instead, for the City in the list of "Party responsible" say something to the effect: 1. Community oversight -per CFR 65.6(a)(12) the City Manager or designee will be the local community official responsible for assuring that the maintenance activities are accomplished. Revised as requested. c. Paragraph starting with "The residential lot owners ... " - 1. This paragraph mentions that the citizens south of Thorpe are benefitting, how so? This statement was removed. 11. Revise last sentence to say something like: The homeowners association of this project, which is composed ofresidential, multi-family and commercial lot owners, is responsible for (details described later): Revised as requested. 2. Section 2.00 a. 1st paragraph - 1. in the list of the PRD facilities include the concrete channel upstream of the pipes, the upstream and downstream headwalls with trash racks and the settling pond. Revised as requested. Response to Comments City of Spokane Valley April 21, 2020 Page 3 ofS ii. Recommend not including the pipe type for the 48" pipes; it does not match the type in the plans. Revised as requested. b. Include triangle pond and Gustin pipe These were added on pages 9 and 10 under Offsite Parent Parcel(s) Drainage Facilities (County) section. 3. Section 3.00 a. Chester Creek i. in the first paragraph 1. it says that the project is to replace the easterly levee but other documents say that the levee is to remain and that fill will be placed landward (eastward) of the levee. Please confirm if the latter is the correct description. The latter is true and the language was revised accordingly. 2. The City will be responsible for maintaining the Creek's bed and banks up to the ordinary high water mark (OHWM); the proponent/HOA is responsible for maintenance above the OHWM. For more information on this please contact Aaron Clary at aclary@spokanevalley.org. The language was revised to reflect this, including the separate 0 & M Manual for the Levee. ii. Maintenance items, third bullet - 1. City will maintain the channel bottom. Revised, please see above. 2. The current conundrum: I do believe the Geotech's recommendation is to only have grasses on the channel banks but Fish and Wildlife wants trees to be kept on the channel banks. We are currently in discussion with F&W about this. The Geotechnical recommendation should govern as this is a flood control issue. Therefore, only grasses should be allowed on the channel banks. Response to Comments City of Spokane Valley April 21, 2020 Page 4 of5 b. Storm Drain mainline 1. In the list of what the storm drain consists of and the maintenance items, consider here including the concrete channel upstream of the pipes and the upstream and downstream headwalls with trash racks ( confirm that these items are included in the costs). Suggest moving the Headwalls/trash racks section on page 6 to here since it seems to be a component of the stormdrain mainline. Up to you. Also, since the function of the trash racks is so critical please consider adding to the maintenance items to inspect function of trash racks during large storm events and for qualified personnel to safely remove obstructing debris if possible. Revised as requested. c. Cross culverts -the City will maintain the cross culverts from the inlet up to but not including the flap gates. Proponent/HOA to inspect and maintain the flap gates and catch basins. The language was revised accordingly. d. Bio-infiltration swale 1. Include the settling pond. Change title to be: Bio-infiltration swale and Settling pond. the language was revised as requested. 11. In the description and maintenance items include those for the settling pond. Revised as requested. 4. Section 4.00 Sinking Funds a. In the calculations- 1. Remove the Madison Road culverts and replace with the flap gates. Revised as requested. 11. Should mowing include the settling pond and the infiltration field? Yes; and this has been revised. m. Debris removal should also include the concrete channel, trash racks, settling pond and the infiltration field. Yes; this has been revised. Response to Comments City of Spokane Valley April 21, 2020 Page 5 of5 iv. Reseeding and noxious weed removal should also include the settling pond and the infiltration field. Revised as requested. v. Include the Chester Creek, triangle pond and Gustin pipe activities. The offsite County facilities were added as separate calculations for clarity. 5. Appendix B Chester Creek O&M a. Again, the City will maintain the channel bottom and banks up to the OHWM. For questions about this please contact Aaron Clary at acJa1y@spokanevall ey.org. If, during a flood, scouring is observed please contact the City Stonnwater Section of Public Works. If, after the flood or during other times of the year, an inspection reveals channel damage below OHWM please contact the City Stonnwater Section of Public Works. The language was revised accordingly. If you have any questions or comments regarding this letter please feel free to contact me at (509) 893-2617. Sincerely, Whipple Consulting Engineers, Inc. Camden Robinson, E.I.T. Encl: CC: Sponsor dWCE Whipple Consulting Engineers MEMORANDUM TO: Allen, P.E. PROJECT NO: Painted Hills REGARDING: Response to Stantec Letter; CLOMR, Ordinance & Hydrology/Hydraulics Details Designers Pre-amble: In regard to the flood control pond located at the north end <?(the project site. Per comments received, additional testing by Budinger and Associates was completed per SRSM methods within the proposed pond area. Bore hole infiltration testing was completed, as full dryivell testing was not allowed within the floodplain prior to CLO MR approval. The result of which are described where applicable in this response letter. For the purpose of the CLOMR application the infiltration from the Budinger report has been used, and the pond has been sized accordingly. The "Budinger Pond" now encompass the area, where the IPEC full scale D,ywell test was completed per IPEC report dated August 21, 2017 (Item 9). It is believed that the infiltration of the native soil is somewhere between the results o_fthese two reports (JPEC 1.8x10-3 and Budinger 4.6296xJ0·6). Therefore, it is the intention of the designer to complete full scale drywell testing within the pond area upon the approval of the CLO MR and issuance of a grading permit. From this testing information the .final size of the pond shall be determined and certified through the LOMR process. Within the provided plan set there are two versions o_f'ponds the Budinger Pond and the JPEC pond, While the Budinger pond will be used.for the CLOMR the IPEC pond as the desired design is provided as well. It is the intention of this project that upon acceptance and approval of the CLO MR by the City and the FEMA, that.full scale drywell tests will be performed on the subject site to better determine an outflow rate. Should the ou(fiow rate diminish with these tests, it should be expected that the large ex;filtration pond will be reduced in size. It should be noted, that prior to the bore hole tests, WCE did submit a plan to pe,form full-scale drywell tests, but were told that we could not do that work in the flood plain until the CLOMR was completed. We have received the comment letter from Stantec Dated August 1, 2019 addressed to Henry Allen, P .E. and offer the following response. For clarity the comments are shown below, where the comment is to be verified as complete the document has been tiuncated with the following symbol[... . .. ]. For additional clarity our response has been provided in bold. City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 2 of89 1 [Stantec] CLOMR DETAILED REVIEW For the previous submittal, Stantec relied on the WCE "Painted Hills Flood Control Development Narrative" dated August 20, 2018 and "DRAFT CLO MR Application for the Proposed Painted Hills Development" that was prepared by West Consultants Inc. and dated August 16, 2018. Stantec had several comments during the Initial Completeness Review related to understanding the proposed conditions and relating the design to the most current proposed configuration. 1. [Stantec] There were numerous documents provided. It was assumed that the document "CLOMR Application for the Proposed Painted Hills Development" would be the narrative provided to FEMA for the CLOMR review, but it is unclear whether or not the other information will be part of the submittal. A lot of information is provided in the "Painted Hills Flood Control Development Narrative", but it is uncertain whether this document will be submitted to FEMA or not. It is recommended that a more clear and easy-to-follow narrative be submitted to FEMA. The review for FEMA will be conducted by personnel unfamiliar with the project and therefore, the information should be presented in such a way that the project narrative, purpose and details can be easily followed and understood. [... . .. ] D The WCE response provides sufficient clarification regarding the project proponents intent for the CLOMR application to FEMA. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 2. [Stantec] The MT-2 Forms and the "CLOMR Application for the Proposed Painted Hills Development" indicate that no change to the hydrology was completed for this task. The CLOMR Application also does not have a detailed write-up of the hydrology. It is Stantec's understanding that the basis of the floodplains being removed from this location is a combination of fill and new infiltration basins. Given the infiltration basins are part of the hydrologic analysis and used a hydrologic program HSPF, it is recommended that a detailed narrative be added discussing the changes to the original Flood Insurance Rate Map (FIRM). For example, initial completeness review indicates that Unnamed Tributary to Chester Creek is being removed from the Flood Hazard mapping. Is the removal based soley upon fill or has the addition of infiltration basins removed floodplain? As stated previously, the FEMA reviewer will not have previous knowledge of the project or the methodologies and procedures used for the analysis. [... . .. ] • [Stantec] The WCE response regarding the Flood Insurance Study (FIS) modeling is City of Spokane Valley -Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 3 of89 sufficient and is supported by the detailed review of the hydrologic and hydraulic models discussed in greater detail in sections 3 and 4 of this review letter. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 3. [Stantec] CLOMR.s require the submittal contain example documentation oflegal notice to be sent to all affected property owners within and outside of the City's jurisdiction, explaining the impact of the proposed action on their property. No documentation was found. [... . .. ] D [Stantec] The proposed solution has been reviewed with City of Spokane Valley and Spokane County staff. Both communities are in agreement with this approach. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 4. [Stantec] CLOMR submittal guidance states that in locations where sediment transport affects hydrology, the effects of sediment transport should be considered in the hydrology and Section F of Form 3 should be submitted. Will sediment have an impact to the infiltration basins? Documentation should be provided in the narrative stating whether or not sediment will have an impact and if so, how it will be mitigated. [... . .. ] D [Stantec] The response from WCE indicates that sediment transport, settlement, and removal has been considered. A review of the Painted Hills Flood Control Development Narrative revised March 6, 2019, indicates the elements in WCE's response paragraphs are included, and a draft Operations and Maintenance (O&M) Plan was made available for review. It is understood that a final O&M document may be held back until the Draft Environmental Impact Statement (EIS) has been released. Comments on the adequacy of the draft O&M Plan are addressed further in later sections (2.1 and 5.4) of these comments. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 5. [Stantec] No shapefiles or CAD files were provided. Spatial files representing the following arerequired: a. New cross-sections and profile centerlines for the new hydraulic model and results; b. New floodplain boundaries; City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 4 of89 c. All of the data used in determining the revised floodplain boundaries, flood profiles and floodway boundaries. This includes the contours developed from the 2003 LiDAR. [... . .. ] D [Stantec] A review of the submitted documents indicates that the above information has been included or addressed as appropriate. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 6. [Stantec] The CLO MR application states that the topography used was the 2003 LiDAR from the effective FIS. However, the person who is assigned to review the CLOMR will not have access to this information. It is recommended that not only do you provide all the LiDAR information including the spatial files, but also the survey report (if available) to illustrate the topography data satifies the FEMA guidelines and specs (Vertical Accuracy needs to be +/-98cm). [... . .. ] D [Stantec] The response provides sufficient indication that the underlying data used in preparing the electronic models supporting the CLOMR application are acceptable to FEMA, and therefore acceptable to the City of Spokane Valley and Spokane County. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 7. [Stantec] The CLOMR submittal requires a certified topography map. In order for this to be completed, a registered engineer or surveyor will need to certify the topographic work map they prepared using the 2003 LiDAR data with a PE stamp. [... . .. ) D [Stantec] A review of the submitted materials includes topographic maps of the project area signed and stamped by a Washington-licensed professional land surveyor. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 2 [Stantec] LOCAL ORDINANCE DETAILED REVIEW This portion of our review has been organized by applicable Spokane Valley Municipal Code (SVMC) ordinance chapter and Spokane County Code (SCC) ordinance chapter. Stantec provided comments with the Initial Completeness Review and WCE responded. For City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 5 of89 brevity, only those items with outstanding issues or where Stantec has provided additional comments have been included herein. 2.1 [Stantec] FLOODPLAIN ORDINANCE SVMC 21.30 c. Watercourse maintenance, Screening comment: A watercourse operations and maintenance plan has been noted as "awaiting completion per jurisdiction comments" (p259, CLOMR application). [... . .. ] D [Stantec] The final version of the watercourse O&M plan must be provided for review before ordinance compliance review can be completed. The submitted documents include a section titled, "Operations and Maintenance Plan For Painted Hills PRD Flood Control System". (PRD is defined as "Planned Residential Development") This section of the submittal appears to address ownership, purpose, describes the general drainage facility layout and function, and includes maintenance requirements and schedule for the drainage facilities, including the box culvert, Chester Creek and levee, concrete channel, storm drain mainline, manholes and catch basins, cross culverts under Madison Road, the bio-infiltration swale, and the drywells and gravel gallery. It also includes a section addressing financing, describing the annual maintenance fund and resulting estimated cost per lot. These items address basic O&M requirements for a Home Owner's Association (HOA). In its capacity as the entity ultimately responsible to assure continued maintenance and operability of the flood management facilities per 44 CFR Part 65.6(a)(12) and City Ordinance 21.30.070.D.7.b, the City may require the project proponents and/or their successors fund a professionally- managed maintenance and operations entity. A detailed review is also included in section 5.4 of this letter, comments 13 -17. Once the official copy is submitted for review, it will be evaluated. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. As indicated in the response to CLO MR review item 4. The draft O& M manual has been submitted and reviewed by Stantec. As Agreed, to in Item 4 The "final O&M document may be held back until the Draft Environmental Impact Statement (EIS) has been released" thus allowing for changes to construction plans to occur. d. [Stantec] Department of Ecology approval will be required for development in a floodplain. (... . .. ) D [Stantec] The ordinance requirement in 21 .30.070.D.7.a is for the City to notify adjacent communities-in this case Spokane County-and the Department of Ecology prior to any alteration or relocation of a watercourse, and submit evidence of such City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 6 of89 notification to the Federal Insurance Administration. As a result, the City may require additional information from the project proponent if Ecology requests such information from the City. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. If the department of ecology makes an official request then the official request will be considered at that time. 2.2 [Stantec] CRITICAL AREAS ORDINANCE SVMC 21.40 (2010 VERSION) ✓ The Critical area report, titled, "Biological Evaluation, Critical Areas Report, and Habitat Management Plan" (Biology Soil & Water, Inc., updated February 28, 2019) has been reviewed against the version of SVMC 21.40 in effect at the time of vesting in 2014. The Critical Area Report is in conformance with the requirements in that document. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 2.3 [Stantec] LAND DISTURBING ACTIVITIES SVMC 24.50 ✓ The City of Spokane Valley Land Disturbance Permit Application has been reviewed and appears complete. As noted above, it is supported by the project plans and documents in the CLOMR application package. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 2.4 [Stantec] FLOOD DAMAGE ORDINANCE SCC3.20 (Spokane County Code) 2.4.1 [Stantec] 3.20.230 Critical Facilities requires "(2) Construction of new critical facilities shall be located outside the limits of the 500-year floodplain when identified on the community's Flood Insurance Rate Map (FIRM), except when no feasible alternative site is available. Critical facilities shall have the lowest floor elevated to or above the level of the 500-year frequency flood. Floodproofing and sealing measures shall be taken to ensure that toxic substances will not be displaced by or released into floodwaters." Critical facilities are defined as, " ... a facility for which even a slight chance of flooding would be too great. Critical facilities include, but are not limited to, schools, child care facilities, hospitals, police, fire and emergency response installations, nursing homes, or installations which produce, use, or store hazardous materials or hazardous waste." ✓ Reviewing the applicants' submitted materials, it does not appear that any Critical Facilities are planned for inclusion in the 500-year (0.2% annual recurrence probability) floodplainarea. WCE Verifies Comment as Complete, please remove this completed item from future City of Spokane Valley -Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 7 of89 comments for ease of review and response. Also, item (3) states, "Access routes shall be elevated to or above the level of the 500-year frequency flood to the extent possible." ✓ [Stantec] A review of the Revised Flood map in the Painted Hills CLO MR Draft compared with the PRD plan set, indicates that the travelled ways in Spokane County's jurisdiction will be outside of the 500-year frequency flood area. However, a version of the proposed condition flood map with the proposed street layout would be very helpful in facilitating any future reviews. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. The project proposes no new streets within Spokane County Jurisdiction. 2.4.2 [Stantec] 3.20.300 Flood plain development permit required/3.20.310 Application for Floodplain Development Permit. • [Stantec] A Spokane County Floodplain Development Permit Application is included with the March 6, 2019 submittal. A review of that document, signed 10/13/16 by Brian Walker of Black Realty, Inc., indicates the application was only for the water- related construction. It includes watercourse alteration and fill material used for water-related construction. As Base Flood Elevation has been established for the area in question, Section F requirements apply. The requirement there is for a surveyor licensed in the State of Washington to stamp and sign the site plan. The Flood Control site plan topographic maps have been stamped and signed by Jon A. Gordon, PLS. However, those maps, in particular Sheet Cl.0 covering the area under Spokane County jurisdiction, do not show the floodplain boundary, nor is there a temporary benchmark with elevation shown. WCE Response: the permit application submitted upon request is the only application that the county has accepted, attempts to update the application have been denied, stating that the hold on the City of Spokane Valley EIS does not allow the county to act upon the property. Updates included the removal of the levee, and an update to the fill and cut material volumes as well as other details such as slopes and streams. The BFE lines have been turned on and the elevation has been certified to the project datum NA VD-88. Also, the surveyor of record has been revised to David Cowell, PLS. Additionally, as this has been included as a part of Painted Hills for flood control as a contributing basin, the County may elect to process this separately, as a separate jurisdiction. We would expect successful conclusion to be a condition of the preliminary plat. 2.4.3 3.20.340(2)(c) ✓ [Stantec] The requirement for hydro logic and/or hydraulic modeling studies from development proponents showing the impact of the proposed development on the base flood elevation has beenmet. City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 8 of89 D[Stantec] Note that 3.20.340(3) requires a certification of the actual elevations showing project compliance with floodplain development permit conditions and requirements for residential structures, stamped and signed by a licensed land surveyor registered in the State of Washington. WCE takes note of the comment and verifies complete: In addition to the permit requirements, a required LOMR will be completed with the construction of the flood control facilities and associated fill. The LOMR will certify to FEMA the final elevations of the project. 2.4.4 [Stantec] 3 .20.340(5) requires that maintenance be provided within the altered or relocated portion of the watercourse so that the flood-carrying capacity is not diminished. A written maintenance agreement for this purpose shall be required and the County Engineer may require the agreement to be recorded. The submitted documents include a statement in the CLOMR Application in Appendix J, "Note: O&M Plans awaiting completion per jurisdiction comments.". D [Stantec] An official O&M Plan is needed for review. However, the submitted documents include a section titled, "Operations and Maintenance Plan For Gustin Ditch Flood Control System". This section of the submittal appears to address ownership, purpose, describes the general drainage facility layout and function, and includes maintenance requirements and schedule for the drainage facilities, including the drainage culvert, conveyance channel referred to as a 3 foot bottom width ditch, a levee along the south side of the ditch, the existing gravel pit, referred to elsewhere as Triangle Pond, and 18 drywells to be installed in Triangle Pond. It also includes a section addressing financing, describing the annual maintenance fund and resulting estimated cost per lot. It appears the required elements of an HOA-based O&M plan have been addressed. However, Spokane County, per 44 CFR Part 65.6(a)(l2) and Spokane County Code 3.20.340(5)(b) may require the project proponents and/or their successors fund a professionally-managed maintenance and operations entity to maintain the proposed Gustin Ditch flood control system. Once the official version of the O&M Plan has been submitted, it will be reviewed. WCE Response: See response to 2.1 item C, If Spokane county makes an official request for a professionally managed maintenance and operation entity. Then the request will be addressed with that jurisdiction and the share of the responsibility between Spokane County and the HOA will be determined, as this is an existing Spokane County storm drainage facility. 2.4.5 [Stantec] 3.20.510 Anchoring. All new development and substantial improvements shall be anchored to prevent flotation, collapse or lateral movement of the structure or works. ✓ [Stantec] A review of the submitted flood control plans indicates engineered slope and watercourse stabilization measures for piping, infiltration areas, and embankments are to be constructed. The PRD road improvements in the flood plain City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 9 of89 are not in Spokane County's jurisdiction. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 2.4.6 [Stantec] 3.20.520 Construction Materials and Methods. ✓ [Stantec] The same comments noted for 3 .20.510 apply to this section. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 2.4.7 [Stantec] 3.20.530 Utilities. ✓ [Stantec] No water supply wells or on-site waste disposal systems are proposed. Standard constmction details for water and sewer systems have been provided; if current standard construction practices are followed during construction, infiltration of floodwaters into the water and sewer systems should be minimal. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 2.4.8 [Stantec] 3.20.540 Subdivision and Other Proposed Developments. ✓ [Stantec] The PRD plans for buildings anticipated to be in areas subject to flooding during a I-percent-annual-chance flood event are not in Spokane County's jurisdiction, WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 2.4.9 [Stantec] 3.20.550 Review of Building Permits. D[Stantec] A building permit application work sheet was submitted with the March 6, 2019 submittal set. The application is for grading. 5,100 cubic yards of native soil fill are noted on the application. Under "Additional Site Information", The box for "Are there any wetlands, streams or ponds within 200 feet of the property?" Is marked, "no". However, the Unnamed Tributary to Chester Creek identified on the Flood Insurance Rate Map is on parcels 45344.9108, and 45343 .9052 according to sheet P 1.3 of the PRD plans. Also, on the same form, the box for "Are there slopes greater than 30% on the property? Is marked "no", but the borrow pit on parcel 45343.9052 appears to have slopes with a drop of 30-feet in 46 horizontal feet. WCE Response: the permit application submitted upon request is the only application that the county has accepted, attempts to update the application have been denied, stating that the City of Spokane Valley EIS does not allow the county to act upon the property until complete. This document will be updated as available, comments noted .. City of Spokane Valley -Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 10 of89 2.4.10 [Stantec] 3.20.610 Residential Construction. ✓ [Stantec] No residential construction is planned for the project in the area under Spokane County jurisdiction. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 2.4.11 [Stantec] 3.20.620 Nonresidential Construction. ✓ [Stantec] No occupied structures are planned for the project in the area under Spokane County jurisdiction. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 2.4.12 [Stantec] 3.20.630 Manufactured Homes and 3.20.640 Recreational Vehicles. ✓ [Stantec] No manufactured homes or recreational vehicle parking areas are planned for siting on the project. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 2.4.13 [Stantec] 3.20.650 Encroachments. ✓ [Stantec] No increase in water surface elevation is modeled for the areas within Spokane County jurisdiction. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 2.4.14 [Stantec] 3.20.660 Floodways. ✓ [Stantec] No floodways, either existing or proposed within the project are within the project improvement area and within Spokane County jurisdiction, except the inlet to the Chester Creek culverts at Thorpe Road. The project hydrologic and hydraulic analyses include the subject culverts, demonstrating that the culverts have been designed to carry the I-percent-annual-chance flood event, and not result in an increase in base flood discharge. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. Note the inlet to the box culvert on Thorpe Rd is within City of Spokane Valley Right-of-way. 2.4.15 [Stantec] 3.20.690 Special Requirements, Flood Storage Areas. ✓ [Stantec] The flood storage area designed for parcel 45343.9052 has a study and design prepared by a Washington-licensed professional civil engineer, that shows the proposed flood storage area will have sufficient capacity to store and infiltrate City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 11 of89 floodwaters for the 1 percent annual chance flood event. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 2.5 [Stantec] CRITICAL AREAS ORDINANCE SCCll.20 (Spokane County Code) 2.5.1 11.20.030 Allowable Uses and Activities within Wetlands, Fish and Wildlife Habitats, and Geo-Hazard Areas. ✓ [Stantec] The proposed filling of greater than 50 cubic yards (5,100 cubic yards) is classified as a limited use in all three critical area categories. The proposed use as a stormwater detention/disposal facility is also limited. Under the 11.20.030.C process flow chart, additional information is required. The project proponents have prepared a Biological Evaluation, Critical Areas Report, and Habitat Management Plan (Biology Soil & Water, Inc., February 28, 2019). Protection measures have been proposed in this document. WCE Response: Comment is acknowledged, the site is currently a Spokane County stormwater detention/disposal facility, revisions will be made when requested by Spokane County, through that process. 2.5.2 [Stantec] 11.20.050 Wetlands. ✓ [Stantec] According to the information presented by the project proponents, no wetlands are on the project site within Spokane County jurisdiction. The project proponents concluded that the waters from the Unnamed Tributary to Chester Creek crossing Spokane County jurisdiction being piped to the borrow pit infiltration basin in parcel 45343 .9052 result in no impacts to regulated waters, so no mitigation is required. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 2.5.3 [Stantec] 11.20.060 Fish and Wildlife Habitat Conservation Areas. ✓ [Stantec] No wildlife priority habitat areas are concluded to be impacted by the project within Spokane County's jurisdiction. However, an east-west 1 O+ acre travel corridor is to be preserved by the developer for wildlife travel across the site by white-tailed deer, elk, and graywolf. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. the project will not block 2.5.4 [Stantec] 11.20.070 Geologically Hazardous Areas. ✓ [Stantec] The project's Biological Evaluation, Critical Areas Report, and Habitat Management Plan did not address geologically hazardous areas. However, several geotechnical reports and addenda have been prepared for the project and have been City of Spokane Valley -Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 12 of89 provided by the project proponents. Among the criteria for geologically hazardous areas are slopes greater than 30%, soils identified by the NRCS as having a sever potential for erosion, both of which are present in the project area within Spokane County jurisdiction. WCE Response: Comment is acknowledged, the site is currently a Spokane County stormwater detention/disposal facility, revisions will be made when requested by Spokane County, through that process. 2.5.5 (Stantec] 11.20.070.C. Regulations. Spokane County Erosion Control requirements apply. ✓ (Stantec] Project proponents have prepared a Storm Water Pollution Prevention Plan/Erosion Control Plan (SWPPP/ECP) for the areas to be disturbed by the project within Spokane County jurisdiction. It does not appear that plan sheet C5 .1, the site plan showing the location of the improvements, includes the locations of the selected Best Management Practices (BMPs) included in the SWPPP/ECP. CS.I does callout side slope seeding using a grass seed specified on the plan. It is unclear if the steeper slopes of the north face of the borrow pit are intended to be seeded. It does not appear that area is intended for regrading to reduce slope steepness, calculated to be 65% (approximately 1 V: 1.5H). A review of the site soils per NRCS web soil survey shows it to be "Urban land-Springdale disturbed complex. Springdale gravelly complex soils in the 11.20.090 Appendix L are shown to have a severe erosion potential. Using the universal soil loss equation estimate confirms a severe erosion potential. Though sediment will be trapped within the borrow pit, it may be prudent from a safety and long-term maintenance perspective for the project proponents to address the erosion potential of the north face slope of the borrow pit. WCE Response: The Gustin Pipe Plan Set Dated 8-20-18, shows the slopes being regraded, Since the County was not allowed to act on the application the review of the plan set was not completed, If Stantec is authorized by Spokane County to complete the plan review then we will address those comments accordingly, other than as a comment to a County application comment noted. 2.6 [Stantec] MOUNDING ANALYSIS REPORT AUGUST 22, 2017, PREPARED BY IPEC, STAMPED BY PAUL T. NELSON. ✓ [Stantec] No comment. Conclusions appear to be supported by calculations. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. Note additional boring tests and infiltration testing, Per SRSM was completed within the triangle pond. The Budinger Report Dated June 1, 2020. Recommended a design infiltration rate between 4.1 cfs and 6.8 cfs. per drywell. The IPEC infiltration Rate used within the mounding analysis was limited to 1.0 cfs per drywell. Since the Budinger design infiltration rate is higher than the IPEC rate used in the analysis it can be concluded that by inspection of the rates that the mound developed from the flood water would be less than originally calculated, and therefore City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 13 of89 verified complete. 3 [Stantec] TECHNICAL REVIEW OF HYDROLOGIC DATA ✓ [Stantec] WCE's response to Stantec's Initial Completeness Review dated March 8, 2019 adequately addresses the hydrologic questions posed. A more thorough review of site hydrologic conditions, proposed stormwater management features, and the indication that all structures will be placed at least 1 foot above the base flood elevations was instrumental in resolving thosequestions. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. [Stantec] Summarizing our understanding of the hydro logic design: [... ...] ✓ [Stantec] The hydraulic design discharge capacity of the proposed features appears to be adequate when compared to the effective discharges. The revised narrative provides a description of the assumptions used by WCE and will be instrumental in the CLO MR application. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. D [Stantec] The infiltration rate in the discussion contained in the revised WCE narrative on narrative page 5 of 6 under the heading "Bio-infiltration pond" doesn't agree with the value used in the Grave] Gallery Cale Sheet in the attachments. Reviewing the backup data provided in Report 9, the Full-Scale Drywell Testing, dated June 28, 2016, and the August 21, 2017 supplement, IPEC's data shows a drywell capacity of 0.149 to 0.151 cfs. Using the SRSM approach from Appendix 4B, IPEC proportioned the qa, allowable flow, to be 1.15 cfs; using a factor of safety of 1.1 appropriate to the very low fines passing the No. 200 sieve, one arrives at the recommended drywell infiltration flow rate of 1.05 cfs for design, which when divided by the typical 600 square feet of drywell infiltration area yields a design infiltration rate of 1.8 x 1 o-3 cfs/square foot. This infiltration rate value is carried forward to the WCE Gravel Gallery Cale Sheet used to calculate the gravel gallery design capacity of 162.64 cfs, including direct infiltration in the gravel fill itself of 116.92 cfs. In the System Summary section of the narrative, the 61,000 square foot bio-infiltration pond is said to have a discharge rate of 1.6 x 10-4 cfs/sf, for a total infiltration capacity of 9.76 cfs. The difference of 105.26 cfs is the bulk of the infiltration capacity claimed for the system. Reviewing the detailed design on sheets CS.31 and CS.32, the gravel gallery section for the drywells shows gravel to 18-feet deep, with perforated 12" pipe extending l0'from the bottom of each drywell barrel. This is consistent with the Gravel Gallery Cale City of Spokane Valley -Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 14 of89 Sheet parameters. Project proponents will need to reconcile the narrative with the calculations and plans. WCE Response: It is understandable that the two infiltration rates do not match. As they are inftltration rates at two different locations. The infiltration rate in the pond bottom is located at the pond bottom and the infiltration rate for the gravel gallery is 18 feet below the existing surface. Please note that with the Budinger report dated January 17, 2020, provided an infiltration test through the Bore hole infiltration test at the depth of the proposed drywells. That infiltration rate while not as accurate as a full drywell test, resulted in an inflltration rate of 2 inches per square foot or 4.6296x10-(j cfs per SF. TO be conservative, the design has been changed to include a pond (Budinger) based upon this infiltration rate. As mentioned previously this is the value and pond size that is proposed to go through the CLOMR process. • [Stantec] It is recommended that WCE validate and/or justify the assumptions that the infiltration rate from the May 6, 2016 dry well test is applicable to the gravel gallery area since the areas appear to be separated by 230 feet. WCE Response: The Budinger Report dated January 17,2020 provided boring and infiltration testing at the new pond location per the SRSM. With the new Budinger pond, as mention previously, the proposed pond area now includes the IPEC full scale Drywell test area. Therefore, there are two tests with significantly differing results, for the CLOMR will move forward with the most conservative. Upon completion of the CLOMR, we would propose several full scale drywell tests for confirmation of either Budinger or IPEC or somewhere in between. Upon completion of that testing program prior to construction, a revised pond size may be warranted. • [Stantec] If the project proponents wish to claim on-site storage as the backup for infiltration in handling the design flooding event, it is further recommended that WCE provide a volumetric analysis demonstrating that sufficient storage is provided to keep flood elevations below the proposed base flood elevations and that corresponding structure elevations are still appropriate if the proposed infiltration rate were to be unrealized or substantially decline. WCE Response: A volumetric analysis has been added to the narrative. •[Stantec] Though the August 21, 2017 supplement to IPEC Report 9 includes a Figure 3 map indicating the drywell location, there isn't a reference on Figure 3 or elsewhere to locate Figure 3 in relation to the rest of the project; from Sheet P3.0 compared to sheet Cl.1 of the Flood Control plan set, it appears this existing drywell was located approximately 230 feet west of the west end of the proposed Gravel Gallery. The Completeness review letter dated December 17, 2018 requested on p7, item 1, " .. please provide an annotated copy or copies of drawing sheet Cl.0 and Cl.3 with indications of flow directions, peak discharges, estimates of runoff volumes, and City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 15 of89 infiltration rates and volumes for a 100-year, 24 hour duration standard storm event base on FEMA Effective Data, Corrected Existing, and Proposed Conditions. Reference points should be placed at flow path splits, structures, significant infiltration points, and hydraulically significant points within the study area. Providing the discharge and volume values in an accompanying table with corresponding points numbers is acceptable." WCE Response: The proposed infiltration facility design outflows are steady state and are not assumed to be volume limited. This follows the assumptions used in the effective FIS. Since inflows to the project are being captured with infiltration facilities that exceed the peak discharges, there was no need to modify the HSPF model to model the proposed conditions. Accordingly, the requested information does not exist. Above ground storage areas included in the design are additional safety measures that are above and beyond what is needed to infiltrate the FIS discharges and remove the project site from the floodplain. ✓ [Stantec] As noted above, the infiltration capacity claimed for the project appears to be at least partially supported. The backup claim is that should infiltration prove insufficient, then the storage volume will be "additional safety measures" that would store enough flood water to prevent a rise in the flood elevation above the established BFE. See recommendation above beginning, "If the project proponents wish to claim ... " WCE Response: The facility infiltration has been updated with the Budinger Report Dated January 17, 2020. As such please see the volumetric analysis of the facility with the Budinger pond provided with the Updated Narrative in the appendix. • [Stantec] Please note the FEMA CLO MR review team may have additional questions, comments, and or request additional data in order to better understand the existing and proposed configurations. ✓ [Stantec] The revised WCE narrative does not include discussion of the design discharges on the main body of Chester Creek. Based on the West Consultants DRAFT CLOMR application it appears these values are not being revised and are consistent with the FEMA FIS (116 cfs near Thorpe Road), but clarification to the WCE front end narrative is recommended prior to submitting to FEMA as a part of the CLO MR application. If a discharge other than 116 cfs was used to design the channel geometry near the intersection of Thorpe Road and Dishman-Mica Road, further review is warranted. WCE: Response: There has been no modification to increase the main line flow within the Chester Creek, only a reduction in flow, as considered in the without channel to the south scenario which would allow a larger volume of water to enter the project site at the Thorpe Road crossing than at the existing box culvert. 4 [Stantec] TECHNICAL REVIEW OF HYDRAULIC DATA As previously mentioned, the revised "Painted Hills Flood Control Development City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 16 of89 Narrative" by WCE dated March 6, 2019 will be instrumental in FEMA's review process for the CLOMR application. That narrative essentially serves as a summary for the West Consultants Inc. CLOMR Application document, which provides the critical support data for the FEMA review of the CLOMR. Much of the additional information provided is support data for the proposed design and for FEMA purposes it should be indicated as such. ✓ [Stantec] For CLOMR purposes, the screening review recommended the previously submitted "DRAFT" CLOMR Application for the Proposed Painted Hills Development" by West Consultants Inc. dated August 16, 2018 be revised to reflect the latest proposed configuration and results without extraneous information. References to options that include levees or a CLOMR-F have been removed in the currently submitted "DRAFT" CLOMR. ✓ [Stantec] The revised WCE narrative clearly explains the design assumptions and revised geometry for the proposed development. The West Consultants CLOMR Application document provides hydraulic support data. The hydraulic design data and provided CLO MR application data reviews generally did not identify any hydraulic design elements for the proposed development that appeared to be fundamentally flawed from a technical stance. The FEMA review team responsible for the CLOMR application may have additional comments and/or request additional clarifications. ✓ [Stantec] In the Stantec Initial Completeness Review, question 4 related consideration of sediment transport impacts on hydrology and hydraulics. WCE has provided a response related to design assumptions and the pending O&M Plan. We concur with that approach and consider this question resolved. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 5 [Stantec] REVIEW OF AUGUST 20, 2018 WCE RESPONSES TO CITY COMMENTS WCE provided responses to City of Spokane Valley Comments on August 20, 2018, on "Painted Hills Floodplain Review #2" provided by the City on January 4, 2017. Stantec has reviewed each request and response against the material included in the March 8, 2019 WCE Painted Hills Flood Control package. 5.1 [Stantec] GENERAL 1. [Stantec] City: Prior to construction permit release, the following needs to be accomplished: a. Copy of CLOMR from FEMA b. Plan approval [... . .. ] ✓ [Stantec] As these items will follow submittal of the CLOMR Application, there is no follow-up needed at this time. WCE Verifies Comment as Complete, please remove this completed item from future City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 17 of89 comments for ease of review and response. 2. [Stantec] City: Prior to construction acceptance, the following needs to be accomplished: a. Copies of the Department of Ecology (DOE) drywell registrations for all new drywells (submitted with construction certification) b. Record drawings showing as-built condition c. Revisions to HBC-RAS model and reassessment of the free board if construction has altered the channels from that depicted in the model d. Letter from design engineers certifying project constructed according to approved plans and specifications e. Levee certifications (44 CFR 65 .10 (e)) f. Construction Certification Package [... . .. ] ✓ [Stantec] As these items will follow construction, there is no follow-up needed at this time. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 5.2 [Stantec] FLOOD CONTROL DEVELOPMENT NARRATIVE 3. City: General -please address the requirement for an overflow path for the 100-year storm mentioned in SRSM chapter 2.2.4, paragraph on Infiltration Facilities. [... ...] ✓ [Stantec] The project proponents have provided hydraulic calculations and supporting geotechnical data showing that the proposed improvements for stormwater overflow management include capacity sufficient to convey and infiltrate not only the I 0-year design storm event as required in SRSM chapter 2.2.4, paragraph on Infiltration Facilities, but also the 100-year storm volume to drywells and the underlying voids in Spokane Valley gravel. As a result, Stantec concludes the current submittal shows conformance with SRSM chapter 2.2.4, paragraph on Infiltration Facilities. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 4. (Stantec] City: Background [... . .. ] a. Page 1 paragraph 1-change "when no flood events occurred" to "when no significant flood events occurred". ✓ [Stantec] The City's request has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 18 of89 [... . .. ] b. [Stantec] Page 2 -since 40th is an east-west oriented street should references to "east of 40th A venue" be changed to "north ( or south) of 40th Avenue"? ✓ [Stantec] The City's request has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. [... ...] c. [Stantec] Change references to "Spokane Rathdrum" aquifer to "Spokane Valley Rathdrum Prairie" aquifer. ✓ [Stantec] The City's request has been addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 5. [Stantec] Main Flow Across Thorpe Road a. Proposed Design [... . .. ] 1. Box Culvert/Open Channel -the text refers to 2-10" culverts but our records saythat they are 18 11 • Please check pipe size. ✓ [Stantec] Based on WCE's statement and a review of the text, the City's comment has been addressed. Noted that there are four 18" culverts under Madison Road. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. [. .. ...) ii. [Stantec] Pipe Mainline -text mentions that along Madison are manholes with sumps but, per WSDOT details, these structures are called catch basins. Please revise. ✓ [Stantec] Based on WCE's statement and a review of the text, the City's comment has been addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. [... . .. ] iii. [Stantec] Gravel Gallery System - l. Paragraph 1-please include the design outflow rates of the drywells and the pipe crosses (may need to provide calcs). ✓ [Stantec] Based on WCE's statement and a review of the text and additional documentation, the City's comment has been addressed. WCE Verifies Comment as Complete, please remove this completed item from City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 19 of89 future comments for ease of review and response. [ ...... ] 2. [Stantec] Paragraph 2 -The design flow of 64 cfs was at Thorpe, please revise the design flow to what it is at the gravel gallery system. ✓ [Stantec] The design flow rate at Thorpe is now shown to be 91 cfs in both the text and the supporting appendix material. As discussed in more detail in Section 3, the technical review portion of this letter regarding hydrologic calculations, the hydraulic capacity of the new box culvert under Thorpe Road is to be 216 cfs. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. iv. Infiltration Rate - 1. Paragraph 1-why is this paragraph included in that TP-29 is at the south end of the site by Thorpe whereas the gravel galleries are at the north end? WCE Response: The paragraph has been deleted. ✓ [Stantec] Based on WCE's response the City's comment has been addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. [ ...... ] 2. [Stantec] Paragraph 2 -please show how the 1.8 x 10-3 cfs/sf design flow rate was derived. ✓ [Stantec] Based on WCE' s response and a review of the referenced supporting document, the City's comment has been addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 6. [Stantec] Secondary Flow Across Madison Road a. Paragraph I [... . .. ] 1. Second sentence -mention that the flow from the most northerly culvert endsup going into culvert at 30+42. ✓ [Stantec] Based on WCE's response and a review of the text, the City's comment has been addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. ii. Third sentence -check that the culvert stations listed match those in the City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 20 of89 table below paragraph 3. WCE Response: Stations revised to match table. D [Stantec] A review of the table shows that in addition to the culvert stations noted in the text, the table below paragraph 3 includes a culvert at Station 38+98, for which West Consultants provided a 100-year storm flow of 7 cfs. However, this particular culvert's station is not specifically mentioned in the text. One can infer that this is the most northerly culvert referred to in the second sentence of the first paragraph that does not have an outlet on the west side of Madison Road; however, please reference that culvert's station in the text as well as in the table. WCE Response: the northern most culvert at STA 39+00 +/-, which has no western outlet has been added to the text and the Stationing has been revised to match the stationing of the plan set. 7. [Stantec] Attachments [... . .. ] a. Provide outflow rate calculations for the HDPE crosses. If the head required to achieve the outflow rate is significant then check this water surface elevation as a downstream condition in the channel and pipe hydraulic calcs. • [Stantec] As noted in Section 3 of this review letter, Stantec has reviewed the hydraulic calculations provided by the project proponents and concerned about the reliance on a single drywell test extrapolated to show infiltration capacity for two separate areas. There is concern related to the underlying soil infiltration rate used in the gravel gallery; please see Section 3 of this letter. WCE Response: the Budinger report dated January 17, 2020 has provided additional bore hole and inftltration testing per SRSM. The Budinger pond area includes the IPEC full Scale Drywell Test Area. [... . .. ] b. [Stantec] Open channel cal cs -the Q may be a little bit more than 64 cfs when the flow from the two pipes at the upstream end of the channel are included. ✓ [Stantec] Based on WCE's response and a review of the text, the City's comment has been addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. [... . .. ] c. [Stantec] Pipe System calcs - 1. Hydraflow is not on FEMA's list of approved software programs. We recommend that before submitting the studyyou check with FEMA to see if they will accept this software. City of Spokane Valley -Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page21 of89 ✓ [Stantec] A review of the submitted material shows that Hydraflow calculations are still included in the submitted documents; they are, however, supplemented by commentary referencing SRSM guidance and supplemented by a report of an XPSWMM model analysis conducted by Ken Puhn of West Consultants. The report of that analysis includes 100-year return event water surface elevations at several system locations. WCE Response: The Hydroflow calculations referred to are the Hydroflow express calculations, used for facility capacity calculations, that are attached to the project narrative, and not within the CLOMR submittal. The Hydroflow Express Calculations are simple repetitive manning's and other hydraulic formula calculations used to determine the theoretical capacities of the facility. Hydroflow Hydrographs was initially used to model the flood event and provide a volumetric analysis. In previous responses that calculation method was removed. Yet a volumetric analysis was again requested. The analysis now provided by West is not generated by Hydroflow, but is the extrapolation of data from the simulated flood event provided by West consultants over 263 hours (11 +/-days). ii. [Stantec] Include the two-foot-high level spreader at the downstream end of the system. W CE Response: A I-foot high spreader, has been called out per the design of the hydraulic engineer (West Consultants). ✓ [Stantec] The 1-foot high spreader is consistent with the SWMM output and appears to be a feasible structure based on the design of the settling basin and gravel gallery presented in the PRD plans provided by WCE (sheet CS.30). WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. d. [Stantec] Gravel gallery - i. Confirm source of the infiltration rate. WCE Response: See IPEC addendum report dated 8-22-17. ✓ [Stantec] Based on WCE's response and a review of the submitted material, the City's comment has been addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 11. [Stantec] Check totals for the sidewall area and bottom area columns. The gravel gallery calculations have been revised with the change to the design. WCE Response: The gravel gallery calculations have been revised with the change to the design. City of Spokane Valley -Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 22 of89 ✓ [Stantec] Based on WCE's response, the revised text, the inclusion of the one- page email report on SWMM modeling, and the annotations in the Hydraflow output, the City's comment has been addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. e. Bio-filtration swale design -the Manning's n of 0.2 is for shallow flow conditions. What depth does King County consider to be "shallow"? The depth calculated in the analysis is over 4 feet. Use a Manning's n applicable to a 4- foot flow depth. WCE Response: The Manning's n-value has been revised per the Open Channel Hydraulics book by Ven te Chow, specifically Curves for A table on Page 182. Please see the appendix of the Flood Control narrative for a copy of the referenced material. ✓ [Stantec] A review of the "Bio-filtration Swale Design" spreadsheet printouts as well as the appended reference material from Chow shows reasonably conservative values ofmanning's n have been used. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 5.3 [Stantec] BIOLOGICAL EVALUATION 8. Section 4.3, paragraph 1-can a vegetative cover be greater than 100% (top of page9}? WCE Response: See Biology Soil and Water, Inc., letter dated June 8, 2017. • [Stantec] We have been unable to locate the referenced letter in the submitted material WCE Response the document is a single page easy to overlook, The BSW answer is yes greater than 100% when you consider vegetation not in just 2 dimensions (2D) but in 3 dimensions. With tree coverage overlapping bushes, and bush coverage overlapping grasses. Therefore, this compounding of overlapping vegetative cover when viewed in a 2D plan view would exceed 100% or the area of the site. BSW Response (6-8-17) (attached) Yes. Where there are multiple canopies including a combination of tree, shrub, herbaceous, the cover may be greater than 100% as is the case in instance referred to in the BE, attached in the appendix to this response. 9. [Stantec] Section 5.3, paragraph 2 -confirm that the items mentioned (work in channel only when dry, BMP's, spill protocols, minimal peripheral impacts, construction fences) are adequately provided in the construction documents. WCE Response: Notes have been added to plans covering these items. ✓ [Stantec] Construction documents now have SWPPP/ESCP documents covering the gravel gallery and Triangle Pond areas that adequately address the City's comment. WCE Verifies Comment as Complete, please remove this completed item from future City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 23 of89 comments for ease of review and response. 10. [Stantec] Section 5.4-confirm that the items mentioned (BMP's, FEMA specifications) are adequately provided in the construction documents. WCE Response: Notes have been added to plans covering these items. ✓ [Stantec] Construction documents now have BMPs and show buffer areas consistent with Section 5.4; the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 11. [Stantec] Section 6.2, page 26-because the levees at the small bridges need to be raised, more than 200' oflevee needs to be raised. WCE Response: See Biology Soil and Water, Inc., letter dated June 8, 2017. • [Stantec] We have been unable to locate the referenced letter in the submitted material. However, the Biological Evaluation format and content appear to be different from what the City commented on and in-line with the infiltrative approach rather than levee enhancement. BSW Response (6-8-17): The plan was changed so it is now estimated that about 400 lineal feet of levee will be raised. WCE Response: the plans have changed again, since this comment, to a fill project. 12. [Stan tee] Section 6. 7, paragraph 1, all of the 1 % flood is being infiltrated. WCE Response: See Biology Soil and Water, Inc., letter dated June 8, 2017. • [Stantec] We have been unable to locate the referenced letter in the submitted material. However, the Biological Evaluation format and content appear to he different from what the City commented on and in-line with the infiltrative approach rather than levee enhancemenl BSW response (6-8-17): The referenced sentence in the report should be considered amended to state "For the Chester Creek Golf Course Overflow Reach, the 1 % annual- chance floodplain within the project site is effectively being intercepted and directed into the inf'tltration facilities located on the north end of the project area rather than entering the existing golf course and infiltrating. WCE Response: The referenced section in the current report is now section 8.6. which has removed the statement altogether. 5.4 [Stantec] OPERATIONS AND MAINTENANCE PLAN items 13 through 17 have not been updated since the review of the Draft O&Mwas completed as stated in section: CLOMR Review Item 4 (This Letter). Therefore, the response to the items have been postponed until the comments can be brought up to date. City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 24 of89 WCE Response: So Noted 5.5 [Stantec] PRELIMINARY GEOTECHNICAL EVALUATION, PHASE 1 18. Analysis and Preliminary Recommendations -paragraph 2 says that soils good for gravel galleries are in the south part of the site. So, the soils in the north part of the site are not good for gravel galleries? l... . .. I ✓ [Stantec] Based on the above response, the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 5.6 [Stantec] FULL-SCALE DRYWELL TESTING 19. Figure 1-show where the test occurred. WCE Response: See IPEC revised report dated 8-21-17. • Figure 3 of the revised report shows the clrywell location, but as noted in Section 3 of this comment letter, it is difficult to tell where that map is in relation to the rest of the project site. WCE Response: The Budinger Report Dated January 17, 2020 has revised the test location and all pertinent information included, see appendix to this document. 5.7 FLOOD CONTROL PLANS 20. [Stantec] Please include the following City project numbers on all plan sheets: a. SUB-2015-0001 (Subdivision) [... . .. ] ✓ [Stantec] Verified; the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. b. [Stantec] EGR-2016-0066 (Engineered Grading Permit) [... . .. ] ✓ [Stantec] Verified; the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. c. [Stantec] FDP-2016-0007 (Floodplain Development Permit) [... . .. I ✓ [Stantec] Verified; the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. City of Spokane Valley -Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 25 of89 21. [Stantec] All ROW dedications and easements shall be recorded prior to the use of the frontage improvements and flood control elements. Dedications for flood control elements need to be recorded prior to LOMR submittal with their file numbers entered on the plans. We have received and reviewed (comments sent December 15, 2016) the following for flood control elements: a. an access easement and a drainage easement for the flood control bioswale and infiltration areas, b. a temporary drainage easement (initially called a temporary construction easement) for the storm drain pipe along Madison Road, and c. a drainage easement along Thorpe Road. [... . .. ] ✓ [Stantec] A review of the plans indicates relevant easement boundaries and types are shown throughout the plan set. Given the project status is pre-LOMR, the City's comments have been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. [... . .. ] [Stantec] City: Please provide draft legal descriptions and exhibits for the following for flood control elements: a. Border Easements along Dishman-Mica that involve a levee, ✓ [Stantec] Given the project status is pre-LOMR, the City's comments have been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. b. [Stantec] Slope easements along levee slopes not covered by a border easement, [... . .. ] ✓ [Stantec] Given the project status is pre-LOMR, the City's comments have been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. c. [Stantec] Access easements along levees that are outside the border easement. [... . .. ] ✓ [Stantec] Given the project status is pre-LOMR, the City's comments have been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. City of Spokane Valley -Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 26 of89 [Stantec] City: Please provide draft legal descriptions and exhibits for the following (non-flood control elements): a. ROW dedication at the NE corner of Thorpe and Dishman-Mica, [... . .. ] ✓ [Stantec] Given the project status is pre-LOMR, the City's comments have been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. b. (Stantec] ROW dedication at the NW corner of Thorpe and Madison, [... . .. ] ✓ (Stantec] Given the project status is pre-LOMR, the City's comments have been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. c. [Stantec] ROW dedication to the BCR's of Roads A through Don Madison, [... ...) ✓ [Stantec] Given the project status is pre-LOMR, the City's comments have been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. [... .. .] d. [Stantec] ROW dedication to the BCR's of Road E and the multi-family driveway approach on Dishman-Mica, ✓ [Stantec] Given the project status is pre-LOMR, the City's comments have been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. e. [Stantec] Border Easements along Dishman-Mica that don't involve a levee, [... . .. ] ✓ [Stantec] Given the project status is pre-LOMR, the City's comments have been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. f. [Stantec] Border Easements along Thorpe and Madison, City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 27 of89 [... . .. ] ✓ [Stantec] Given the project status is pre-LOMR, the City's comments have been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. g. [Stantec] Access easement for Dishman-Mica sidewalk that meanders into site. [... . .. ] ✓ [Stantec] Given the project status is pre-LOMR, the City's comments have been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 22. [Stantec] Based on the street classification and project soil types, a pavement design shall be required for Dishman-Mica, Thorpe and Madison per SVSS Chapter 8. WCE Response: A pavement design has been provided in IPEC report dated June 26, 2017. See flood control narrative for referenced report. D [Stantec] The referenced report has been reviewed and includes an industry standard approach to pavement design recommendations. The PRD plans have been reviewed and pavement sections are included on sheet P2.0 of that plan set. However, the plan sheet sections do not completely agree with IPEC's recommended sections for aggregate base thickness, though the thickness design parameters are within the range of standard sections for Spokane Valley. WCE Response: The Plan Set has been revised to match the recommended pavement sections. 23. [Stantec] Please submit a striping and signage plan for Dishman-Mica Road. Coordinate with the Traffic Impact Analysis for required left tum lanes and two-way left tum lanes. Show how the two-way left tum lane will taper at the Chester Creek crossing where the pavement section narrows. WCE Response: Signage and striping plans for Dishman-Mica Road, Thorpe Road, and Madison Road have been provided on sheets ClO.O, CIO. l ,& CI0.2 ✓ [Stantec] The referenced drawings sheets are included in the plan set and include the requested two-way left tum lane and taper on Dishman-Mica Road. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 24. [Stantec] Please provide a Design Deviation Request for the following: a. Two driveway approaches for Dishman-Mica Road (SVSS 7.8.2.b) D [Stantec] No response has been received from WCE regarding this request, or a response City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 28 of89 has not been forwarded for review. WCE Response: See Revised Plans, only a single driveway to Dishman-Mica Road has been provided for the commercial site pad, see sheet C3.0l @ ST A 28-75 +/-(RT). Therefore, comment no longer applies. 25. [Staniec] For proposed utility adjustments and relocations, the applicant/engineer is required to contact each utility purveyor impacted by the required utility relocations and:- a. Discuss with the purveyor the proposed work including relocations and adjustments as well as the costs for these activities, WCE Response: So Noted, with the revised plans coordination with the water and sewer purveyors will be completed. • [Stantec] Submitted plans include water and sewer utility connections, which evidence at least some plan coordination with the utility providers. Costs have not been included with the materials available for review. WCE Response: Until this project has been through the public hearing process Utility coordination is limited, as well as project costs. A 30% to 50% utility design level for construction plans is occurring prior to being heard by a hearing examiner, who establishes project conditions, and standards. Utility plans will be formalized upon project approval by the affected utilities. b. Obtain from the purveyor a written statement that they acknowledge and concur with or have alternatives for the needed work, and WCE Response: So noted. • Written statements from utility purveyors were not included in the materials available for review. WCE Response: The preliminary plat application has the appropriate will serve letters of service guarantee, no other submittal to the City for utilities outside their approval authority will be made until after preliminary plat approval. c. [Stantec] Forward a copy of the statement to Spokane Valley Development Engineering. Receipt of statements will be required prior to civil plan approval. WCE Response: So Noted. • Written statements from utility purveyors were not included in the materials available for review. WCE Response: The preliminary plat application has the appropriate will serve letters of service guarantee, ,io other submittal to the City for utilities outside their approval authority will be made until after preliminary plat approval. d. [Stantec] Show the location of any relocated utilities. City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page29 of89 WCE Response: Relocated utilities are shown on the Water and Sewer plans. ✓ [Stantec] Relocated utilities have been verified to be shown on the street and Water plans. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 26. [Stantec] Please submit a drainage report for the roadside swales. Include curb inlet and non-flooded roadway width calculations. WCE Response: A drainage report has been prepared for the roadway frontage. ✓ [Stantec] A drainage report was included and reviewed. The report follows SRSM requirements for analyses and content. No further comments are deemed necessary regarding the report content. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 27. [Stantec] Confirm there is maintenance access to all stormwater and levee facilities (SRSM 11.1.6) and provide approaches where accesses connect to a road. WCE Response: Maintenance access has been provided for storm and flood control facilities. ✓ [Stantec] A review of the provided plans verifies maintenance access has been provided for the storm and flood control facilities. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 28. [Stantec] If flood flows varied from those modeled and they ended up exceeding system design, for instance at the infiltration/gravel gallery area, will there be any time for response between the exceedance occurring and properties being inundated? WCE Response: As Flood Events occur over a period of days and weeks there is time to manage the flood control facilities if need be. The proposed flood control facility is designed to handle the 100-year flood event, with additional design capacity as a part of the design safety factor. In addition, a surge protection at the open channel and headwall is included that will take the surge into the lowered park area. This additional storage would eventually be channeled back into the flood system via a catch basin and pipe to the west 48" pipe. For any Flood event beyond the 100-year event the proposed finish floor of the residences and the commercial buildings are graded above the BFE, so any flooding would be maintained in the streets, with minimal incursion into the structures. See Flood Control Narrative for specific design information. D [Stantec] Proponents' response is generally consistent with the provided design and calculations, except as noted in comments in Section 3 of this letter. City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page30 of89 WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. Section 3 is the technical review of hydrologic data, and addresses the infiltration rates, a volumetric analysis, and the capacity of the Budinger pond facility have been provided, the proposed facility is sized so that adequate time will/would be available. 29. [Stantec] Incorporate into the design the recommendations mentioned in: a. The Biological Evaluation in sections 5.3 (e.g. best management practices, construction fences around minimized work areas, restoration of impacts) and 6.5 (signs). WCE Response: As the Levees are no longer part of the flood control system it is proposed that the implementation of the biological evaluation and management plan be prepared after the completion and survey of the completed fill, otherwise an approved plan would have to be modified once the fill is surveyed. • [Stantec] The Biological Evaluation documents submitted with March 5, 2019 package is organized differently from the comment and WCE's response. It appears that the design has incorporated the key recommendation of the current Biological Evaluation, including: o Buffer widths, o Vegetation for noxious weed control, erosion and sediment control, and habitat enhancement However, wetland buffer notification signs or placement were not noted in the design documents. b. O&M Manual, Drainage Facilities section (signs). WCE Response: Signs are proposed to be placed upon fences. • [Stantec] So noted. Drainage facility signs were found in one location in the plan set. Sheet C5.30 contains a callout for placement of sign. However, precise location is not identified. WCE Response: The Flood Control Facility Sign on Sheet CS.to is not the Proposed Stream Buffer Sign Proposed in the BSW report. As the biological evaluation and management plan will occur after the flood control grading has been completed the biological implementation will be incorporated in the construction plans after the Public Hearing. See original response to item 29a. City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page31 of89 Sheet CO.O 30. [Stantec] In the 'Dev. Const. lnsp.' contact information section, please revise the phone number to 599-6306 and the contact name to Ken Van Dyk. In the 'Roadways' section, please change the phone number to 720-5008 and remove the contact name. Applies to Sheet C9.0 as well. WCE Response: Contacts have been revised on sheets CO.O and C9.0. ✓ [Stantec] Plan review verifies that this has been done. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 31. [Stantec] Make sure all sheet titles match the titles in the Sheet Index. WCE Response: Sheet titles and/or sheet index have been revised to match. u [Stantec] Sheet index needs to be updated to include C7.X Water Utility plans and C8.X Sewer Utility plans. In addition, plan sheet references were changed in this submittal and many callouts were not updated with new numbering and sheet names. WCE Response: The sheet and or sheet indexes have been revised to match, and detail callouts have been reviewed. Sheet CO. !(General Notes) 32. [Stantec] SV Note #6 -change should to shall. WCE Response: Note revised to read "shall." ✓ [Stantec] Spokane Valley General Construction note #6 now reads, "shall". WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. Sheet C0.2 (Dishman-Mica Road Sections) 33. [Stantec] For the Dishman-Mica Road Widening Calculations: a. Provide a column that depicts the existing super-elevated cross-slopes and adjust the proposed cross-slopes to match. The minimum proposed cross- slopes shall be 2%, WCE Response: The widening calculations have been revised and the cross slope has been matched. !J [Stantec] Review of Sheet C0.2 confinns WCE's response. However, the minimum proposed cross slopes are less than 2% from Station 27+00 through 32+00, then Stations 32+85.69 and 33+00. However, these variances do match the existing cross slopes as requested. City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 32 of89 WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. b. [Stantec] Check the Proposed Curb Elevations. WCE Response: The proposed curb elevations are based upon the varying cross slope and have been checked accordingly. • [Stantec] A spot check of curb elevations corroborates WCE's response and appears to match theplans. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 34. [Stantec] For Sections 1-3, please: a. Label the street centerline, WCE Response: The centerline has been labeled. • [Stantec J A check of the sections verifies use of the standard centerline symbol. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. b. [Stantec] Revise the cross-slope of the pavement widening to match the existing super-elevated cross-slopes and provide the range of cross-slopes, WCE Response: The cross slopes have been revised to match the existing cross slope. • [Stantec] A plan check verifies that the design cross slopes match the existing cross slopes. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. c. [Stantec] Verify the pavement section with a pavementdesign. WCE Response: See IPEC Geotechnical Evaluation dated June 26, 2017. J [Stantec] The pavement sections generally follow the guidance of the referenced report; however, in this case on Dishman-Mica the design aggregate base is 6- inches rather than the IPEC-recommended 12-inches in depth. See comment response 22. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. The pavement sections for Dishman-Mica has been revised to have a base of 12". d. [StantecJ Specify PG 70-28 for the HMA pavement. WCE Response: The HMA pavement type has been added. =:I [Stantec] A review of the plans veiifies that the City's comment has been adequately addressed. City of Spokane Valley -Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 33 of89 WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 35. [Stantec] For Section !,please: a. Revise the planter strip width to 7' per SVSS 7.5.10. WCE Response: The planter strip width has been revised. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. b. [Stantec] Extend the border easement to the toe of the slope or provide a separate slope easement, WCE Response: The border easement has been extended to encompass the toe of slope. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. c. [Stantec] Reference SVSS Standard Plan R-103 for the 6' sidewalk. WCE Response: The Standard Plan has been referenced. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 36. [Stantec] For Section 2, please: a. List the range of pavement widths, WCE Response: The range of pavement widths does not vary within the cross section. The pavement width does change at the bridge crossing and becomes 19' wide. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. b. [Stantec] Remove the 10' border easement. WCE Response: Border easement has been revised to 15' ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 34 of89 addressed in a manner consistent with other comments. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 37. [Stantec] For Section 3, please: a. Verify the need for the roadside swale, WCE Response: The roadside swale along Dishman Mica Road has been reduced in size, and will capture any project flow and receive plowed snow from the road surface. ✓ [Stantec] The City's comment has been adequately addressed in a manner consistent with other comments and responses. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. b. [Stantec] Extend the border easement to the toe of the levee slope or provide a separate slope easement, WCE Response: The border easement has been revised. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. c. [Stantec] List the range of pavement widths WCE Response: The range of pavement widths are shown. See previous response. ✓ [Stantec] A review of the plans indicates the range of pavements widths applicable to Section 3 is 19-feet to 22 feet; both values are shown on the section, with the 19-foot value included in "Pavement Width is 19' at Chester Creek Crossing". In that sense the City's comment has been addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. d. Adjust the 34' and 64' dimension strings to end at the ROW. WCE Response: Dimension strings have been adjusted. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. e. [Stantec] the 8' asphalt path: locate the construction line location and specify City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page35 of89 the pavement section and a cross-slope. If maintenance vehicles will utilize the asphalt path, verify the width and pavement section. WCE Response: The asphalt path width and cross section have been revised to a IO-foot path with I-foot shoulders. An alignment has been added and will act as the construction line. • [Stantec] From the revised plans, the WCE response is accurate. However, the asphalt path pavement section is not shown. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. The pavement section for the to-foot asphalt path has been provided on Sheet C0.2 Detail 3 Dishman-Mica Rd Cross section. Sheet CO. 3 (Thorpe and Madison Road Sections) 38. [Stantec] For Section 4, please: a. Provide applicable stationing for this section. WCE Response: Stationing has been added to the section. J [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. b. [Stantec] Reference SVSS Standard Plans R-102 for the curb and gutter and R- I 03 for the sidewalk, WCE Response: The standard plans have been referenced. D [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. c. [Stantec] Verify the pavement section with a pavement design. WCE Response: See IPEC Geotechnical Evaluation dated June 26, 2017. 0 [Stantec] The pavement sections generally follow the guidance of the referenced report; however, in this case on Thorpe the design aggregate base is 6-inches rather than the IPEC-recommended 12-inches in depth. See comment response 22. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. The pavement sections for Thorpe Road has been revised to have a base of 12". 39. [Stantec] Provide a separate cross section of Thorpe Road that includes the concrete channel. City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page36 of89 WCE Response: For clarity and simplification, the cross section of Thorpe Road and the channel/box culvert has been provided on Sheet C5. l. A note has been added to this affect. ✓ (Stantec] A review of the plans indicates the response is generally correct. However, the note on plan sheet C0.3 states, "See Sheet CS.2 for details"; when looking for that sheet, the detail sheet with the referenced detail is actually numbered "CS .1 0" in its title block. The sheet index on C0.0 is consistent with the "C5.l 0" designation. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. The callout is no longer needed and has been removed. 40. [Stantec] For Section 5, please: a. Provide applicable stationing for this section. WCE Response: Stationing has been added to the section. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. b. [Stantec] Provide a pavement and gravel section for the meandering path, note that this path will be used by a vactor truck to clean out drainage facilities, WCE Response: A pavement section has been provided. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. c. [Stantec] Label the range of cross-slopes for the widening per the widening calculations, WCE Response: The slope has been revised to be 3.00%. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. d. [Stantec] Adjust the border easement width to account for the meandering path. WCE Response: The boarder easement has been revised to the width of the proposed tract. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 37 of89 comments for ease of review and response. e. [Stantec] Label the varying swale widths to account for the meandering path. WCE Response: The swale width is uniform, the cross section has been revised to reflect the unifonn width with a note listing the range of widths from swale to path. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. f. [Stantec] Label the dimension from the ROW to the centerline of the 60" storm pipe. WCE Response: This dimension has been added to the 2-48" pipes. D [Stantec] A dimension line has been added from the ROW line to somewhere on the more easterly 48-inch pipe. However, from the detail as drafted it is unclear where that dimension is supposed to intersect the pipe. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. The dimensions have been revised to be from the ROW line to the centerline of the easterly pipe, from the center of the easterly pipe to the westerly pipe and then to the boarder easement. g. [Stantec] Verify the pavement section with a pavement design. WCE Response: See IPEC Geotechnical Evaluation dated June 26, 2017. ✓ [Stantec] A review of the plans and the referenced report verifies that the City's comment has been adequately addressed; in this case the IPEC report and section call-out agree. See comment response 22 for additional detail. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 41 . [Stantec] For Sections 4 and 5 and the roadside swales, include the following or provide a separate swale section: a. 3: 1 maximum side slopes, WCE Response: The slope has been labeled on a typical section. J [Stantec] A review of the plans and the referenced report verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. b. [Stantec] 12" treatment soil zone. WCE Response: The treatment soil has been called out on a typical section. • [Stantec] A review of the plans verifies that the City's comment has been adequately City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 38 of89 addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. c. [Stantec] If the following treatment soils are installed, the City of Spokane Valley does not require soil testing per SRSM: "For swales and ponds, the top 12 inches of soil shall consist of a thoroughly blended mix of 50% compost with 50% native soils." WCE Response: So noted. A note has been added to the typical swale section. '.J [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. d. [Stantec] Note requiring swale bottoms and side slops shall be lined with sod/hydro seed. WCE Response: A note for hydro seeding has been added with a seeding note on Sheet C4.1. D [Stantec J The note for hydro seeding is on C0.3. No Sheet C.4.1 was in the plan set. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. A note on C0.3 references the hydro seeding note on sheet CS.31. e. [Stantec] Typical bottom dimensions and depth, WCE Response: A typical cross section has been provided with the elements of items a through f. D [StantecJ A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. f. [Stantec] Show a typical drywell or catch basin section with the 611 treatment depth and minimum depth from rim to flow line. WCE Response: A typical catch basin has been shown with call outs of 0.5' bottom to rim and 0.8' bottom to flowline. ::::J [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 39 of89 Sheet Cl.3 (Site Element Plan) 42. [Stantec] Coordinate the 'Madison Rd Easement Plan' section with Sheet C0.3. WCE Response: The plan and section have been coordinated. • [Stantec] The Madison Rd Easement Plan section is similar to the section 5 shown on C0.3, except the dimensions from the ROW line to the east-most pipe are different. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. See response to 40f 43. [Stantec] Plan view calls out 2-10" culverts under Thorpe but our records say that they are 18 ". Please check the pipe size. WCE Response: We have checked and measured the culverts in the field and there are 3-15" CMP culverts. The text has been revised. ✓ [Stantec] A review of the plans and associated documents verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. Sheets C3.00 -C3.23 44. [Stantec] Reference intersection detail sheet at all applicable intersections. WCE Response: The intersection detail sheet was referenced with the centerline-centerline callout in the plan view. ✓ (Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 45. [Stantec] Make sure all proposed and existing ROW and all easements are labelled. a. Where levee is outside the ROW and Border Easements provide access and slope easements. WCE Response: The ROW and easements have been labeled. 0 [Stantec] A review of the plans indicates there are some sheets on which some easements have not been labeled; otherwise, the review verifies that the City's comment has been addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. The sheets have been reviewed to ensure all applicable easements have been shown. heet C3.00 (Dishman-Mica Road P&P) 46. [Stantec] For the sidewalk that extends from Dishman-Mica Road to onsite: a. Provide the station and radius of the curve, City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 40 of89 WCE Response: A reference is made to see sheet C3.03. Sheet C3.03 has a plan and profile for the sidewalk. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. b. [Stantec] Provide a plan view that shows the entire alignment of the onsite sidewalk. WCE Response: Plan view has been added on sheet C3.03. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. c. (Stantec] Provide finish grade spot elevations that comply with ADA guidelines and include a cross-slope for drainage. WCE Response: Profile has been added on sheet C3.03. Cross slope callouts have been added on sheet C3.03. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. d. [Stantec] Show and label the access easement for all portions of the sidewalk located onsite. WCE Response: Access easement has been added on sheet C3.03. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 47. [Stantec] Please identify the existing hydrant near STA 22+40 and the power pole and telephone pedestal near STA 22+60. Determine ifrelocations are required. WCE Response: The existing fire hydrant has been called out. There is no relocation necessary. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. City of Spokane Valley -Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 41 of89 48. [Stantec] For the new guardrail it will need to extend farther to the south than indicated on the plan due to the posted speed limit and slopes. The curb and gutter does not provide an adequate barrier in this situation. Verify the required length of the guardrail and the clear zone requirements with AASHTO Roadside Design Guide. WCE Response: New guardrail has been called out two feet behind the curb at the location of the existing guardrail. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 49. [Stantec] For Construction Note #10, specify the start STA for the guardrail and reference new guardrail only. WCE Response: Stationing for new guardrail has been added. See construction note 9. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 50. [Stantec] For Construction Note #11, specify the start and end stations of the pavement taper. Therequired taper length shall be calculated per L = ws, where 'w' is the widening width and 's' is the posted speed limit of 45 mph. WCE Response: The pavement taper south of the Dishman-Mica Rd box culvert and at the north end of the property has been calculated by L=WS and the start and end stations have been called out. The taper just north of the Dishman-Mica Rd box culvert has been widened per the meeting on 6/12/17. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. However, station callouts do not have offsets, which would help verify calculation. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. offsets have been added. 51. [Stantec] The Traffic Impact Analysis mentions streetlights along Dishman- Mica. Please show the light locations and specify that the lights will be installed with the plat. Specify necessary conduit sleeves to be installed with the frontage improvements. WCE Response: Street lights have been called out at public intersections. D [Stantec] In review of the plans, new street light location is not identified at Thorpe Road intersection where an existing light is getting removed. Conduit locations not City of Spokane Valley -Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 42 of89 identified in plans. However, note for Sundown Rd intersection indicates "coordinate final location and power supply with Inland Power". WCE Response: Sheet C3.0 has been revised to show that the existing light will be removed and replaced with like and kind similar to sundown. 52. [Stantec] In the profile, adjust the Top of Curb elevations to match the existing super- elevated cross slopes and the revised Road Widening Calculations from Sheet C0.2 WCE Response: The TBC has been revised to match the existing super-elevated cross-slopes. :J [Stantec] In review of the plans, most elevations are matching Sheet C0.2. However, TBC elevations at Stations 25+00, and 25+50 do not match table. WCE Response: The profile and tables on Sheet C0.2 have been coordinated to match. Sheet C3.0l (Dishmru'l-Mica Road P&P) 53. [Stantec] For Construction Note #2, please reference Sheet C0.2. WCE Response: Sheet C0.2 has been referenced in construction note 2. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 54. [Stantec] For Construction Note #3, please reference a 'spill' curb, similar to Sheet C3.00. WCE Response: Spill curb is now referenced in construction note 3. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 55. [Stantec] For Construction Note #4, reference the appropriate plan sheet and detail for the asphalt path details. The City does not have specific standards for asphalt pathways. WCE Response: Sheet and detail are now referenced in construction note 4. ✓ [Stantec] A detail is not referenced in note 4. However, pathway section infonnation is provided in note. Therefore, a review of the plans indicates the intent of the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 43 of89 56. [Stantec] Since the 8' pathway will be driven on, provide adequate turning radii around the approaches. WCE Response: With the removal of the levee the path will no longer be driven upon. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 57. [Stantec] Verify Construction Note #5 for this sheet. WCE Response: Note 5 has been revised to reference a different construction item. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. Note 5 is no longer being reference and noted as "Reserved". WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 58. [Stantec] For the pedestrian ramps at Road 'E', provide sidewalks on each side of the Road 'E' to down to the ramps or provide sidewalks from the top of the levees down to the pedestrian ramps. Short sections of adjacent sidewalk at the ramps will be acceptable. WCE Response: Sidewalks and ramps are now provided at Sundown Road (road E). ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 59. [Stantec] Road E-show how stormwater flowing down/along Road Eis captured before it gets to Dishman-Mica and is disposed of. WCE Response: Plan has been revised to direct stormwater off Sundown Rd via under Type 2 curb inlets into roadside swales behind the sidewalk/curb. See sheet C3.03 for details. • [Stantec] In review of the plans, this does not appear have been addressed. There are no Type 2 curb inlets called out on Sundown and details are not provided on sheet C3.03. In fact, although not called out anywhere in the plans, the plan view shows inlets on Dishman-Mica where the spill curb is located (which won't direct flow to the swale). A transition from spill curb to standard curb needs to occur if inlets remain on Dishman-Mica and there are no Type 2 inlets indicated on Sundown. WCE Response: With the change from levee to fill, Sundown no longer needs to extend so far into the project to get over the levee. The intersection plan has been revised and fture City of Spokane Valley -Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 44 of89 type 2 and ponds have been shown at the Sundown PC/PT's. 60. [Stantec] For Construction Note #10 please verify the Standard Plan R-113 reference, as it is intended for adjacent sidewalks. WCE Response: Note has been revised to reference Std Plan R-111. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 61. [Stantec] For Construction Note #12, please verify the sheet reference. WCE Response: Note has been revised to reference sheet C4.2. • [Stantec] In review of the plans, note #12 has been changed to "Reserved". Perhaps callout is no longer required as there is no Sheet C4.2 in plan set. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. The callout is no longer in use. 62. [Stantec] For Construction Note #15, specify the start and end stations of the pavement taper. The required taper length shall be calculated per L = ws, where 'w' is the widening width and 's' is the posted speed limit of 45 mph. WCE Response: Taper stations have been added. Per meeting at the City, the taper length has been shortened to provide full width widening at the driveway approach. • [Stantec] In review of the plans, taper occurs on sheet C3.02 and it is unclear what length the taper is supposed to be because offsets are not provided. The calculations show 17 5 ', plan view has the taper at 163' based on station call outs, and Note 9 indicates 220.5'. It is unclear which taper length is intended. WCE Response: Sheet C3.02 has been revised to show a 175' length taper. Please see sheet C3.02 for details. 63. [Stantec] For the approach at STA 35+25, show the curb returns and provide pedestrian ramps. Provide sidewalks down to the ramps. WCE Response: This is outside the match line and shows on sheet C3.02 ✓ [Stantec] A review of the plans verifies that the City's comment is addressed regarding sheetC3.02. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. Note, the pedestrian ramp is intended to be flush with tactile warning and bollards. 64. [Stantec] Provide Type Ill barricades per SVSS Standard Plans R-142 at each approach and Road 'E' until they are operational. City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 45 of89 WCE Response: Construction note 13 added to provide for ban-icades. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 65. [Stantec] Please provide centerline stations for the driveway approaches at STA 28+75 and35+25. WCE Response: Centerline stations have been added. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 66. [Stantec] In the profile, adjust the Top of Curb elevations to match the existing super- elevated cross-slopes and the revised Road Widening Calculations from Sheet C0.2. WCE Response: The TBC elevations have been revised to match the super-elevated cross-slopes. '.J [Stantec] In review of the plans, most elevations are matching Sheet C0.2. However, TBC elevation at Station 32+50 does not match table. WCE Response: The TBC elevations and spreadsheets have been coordinated to match, except when maintaining positive drainage. Sheet C3.02 {Dishman-Mica Road P&P) 67. [Stantec] See all applicable review comments from Sheet C3.01 for this sheet. (53) For Construction Note #2, please reference Sheet C0.2. WCE Response: Sheet C0.2 has been referenced in construction note 2. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. (54) [Stantec] For Construction Note #3, please reference a 'spill' curb, similar to Sheet C3.00. WCE Response: Spill curb is now referenced in construction note 3. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. City of Spokane Valley -Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 46 of89 (55) [Stantec] For Construction Note #4, reference the appropriate plan sheet and detail for the asphalt path details. The City does not have specific standards for asphalt pathways. WCE Response: Sheet and detail are now referenced in construction note 4. ✓ [Stantec] A detail is not referenced in note 4. However, pathway section information is provided in note. Therefore, a review of the plans indicates the intent of the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. (56) [Stantec] Since the 8' pathway will be driven on, provide adequate turning radii around the approaches. WCE Response: With the removal of the levee the path will no longer be driven upon. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed if levee has been removed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. (57) [Stantec] Verify Construction Note #5 for this sheet. WCE Response: Note 5 has been revised to reference a different construction item. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. Note 5 is no longer being reference and noted as "Reserved" WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. (63) [Stantec] For the approach at STA 35+25, show the curb returns and provide pedestrian ramps. Provide sidewalks down to the ramps. WCE Response: The plan has been revised. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. A commercial driveway per R-111 is now being proposed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. the commercial driveway per std plan R-115, at the path interface a tactile warning surface has been placed and called out. (64) [Stantec] Provide Type Ill barricades per SVSS Standard Plans R-142 at each approach and Road 'E' until they are operational. WCE Response: None given. (addressed in comment 73) ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 47 of89 addressed. Barricades are provided in Note 11. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. (65) [Stantec] Please provide centerline stations for the driveway approaches at STA 28+75 and 35+25. WCE Response: Centerline stations have been added. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. (66) [Stantec] In the profile, adjust the Top of Curb elevations to match the existing super-elevated cross-slopes and the revised Road Widening Calculations from Sheet C0.2. WCE Response: The TBC elevations have been revised to match the super- elevated cross-slopes. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 68. [Stantec] Please remove the extraneous hextag #1 near STA 39+75. WCE Response: The Hex tag has been removed. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 69. [Stantec] For levee and 8' path to be installed on church property from STA 35+82 to 39+80: a. Please provide evidence of granted pennission from the church to build on their property. WCE Response: With the removal of the Levee from the flood control system the levee on the church property has also been removed ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. City of Spokane Valley -Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 48 of89 b. [Stantec] Provide access, slope and construction easements. WCE Response: A slope and construction easement has been shown. See sheet C4.0. • [Stantec] In review of the plans, a 36' border/levee access and maintenance easement is indicated on the sheet, it is unclear if this is still the case based on comment #69. No easements are indicated on Sheet C4.0. Sheet CS.0 has a note indicating "Temporary access & drainage easement to be altered at final plat". Temporary access, slope and construction easements should be established prior to construction, not at final plat. WCE Response: This wider easement is no longer needed and has been replaced by a standard 15' border easement. 70. [Stantec] For Construction Note #9, specify the start and end stations of the pavement taper. The required taper length shall be calculated per L = ws, where 'w' is the widening width and 's' is the posted speed limit of 45 mph. WCE Response: Stations have been added. :::J [Stantec] In review of the plans, it is unclear what length the taper is supposed to be because offsets are not provided. The calculations show 175', plan view has the taper at 163' based on station callouts, and Note 9 indicates 220.5'. It is unclear which taper length is intended orrequired. WCE Response: Sheet C3.02 has been revised to show a 175' taper. The notes have been revised to specify a 175' taper. 71. [Stantec] Any relocated utilities shall be located outside of the clear zone. WCE Response: Construction note 7 required relocations to be outside the clear zone. Additional utility items have had hextags added. ✓ [Stantec] In review of the plans, there are no hextags added to plan view. However, the note covers the possibility and directs contractor to coordinate with the appropriate agency prior to relocation. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. Hextag 7 has been placed where removal is apparent. The note is provided for those items where the impact is to be revealed during construction. Both methods ensure compliance with City standards. 72. [Stantec] For Construction Note #10 please verify the Standard Plan R-113 reference, as it is intended for adjacent sidewalks. WCE Response: Note has been revised to reference Std Plan R-111. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 49 of89 comments for ease of review and response. Standard Plan R 113 has been referenced. AS R-113 provides the configuration needed for the right-in right-out restriction to the driveway per the traffic study, and maintains the separated 10-foot path. 73. [Stantec] Provide Type Ill barricade per SVSS Standard Plans R-142 at the approach until it is operational. WCE Response: Construction note 11 added to provide for barricades. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. Sheet C3 .10 (Thorpe Road P &P) 7 4. [Stantec] In the Left Top of Curb Profile, show all text for the vertical curves. WCE Response: Profile adjusted to show all text. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 75. [Stantec] In the profiles, the minimum 'k' value for sag vertical curves is 50 per SVSS Table 7.1. WCE Response: As requested in the 6/12/17 meeting the difference in elevation between a VC with K=50 and a VC with a K=40 has been calculated. The difference is 0.59'. Due to the lack of room to lengthen the existing VC the grades had to be changed to calculate the VCwith K=50. ✓ [Stantec] A review of the plans verifies that the City's comment has been addressed based on information provided. However, WCE response intended to convey that the grades had to be changed to calculate the VC with K=40 (not 50). WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 76. [Stantec] In the profiles, the minimum 'k' value for crest vertical curves is 30 per SVSS Table 7.1. WCE Response: The length of room provided in this area of Thorpe allowed for the VC to be lengthened and meet the K value of 30. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. City of Spokane Valley -Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 50 of89 77. [Stantec] For Construction Note #2, please reference Detail 4 on Sheet C0.3. WCE Response: Reference revised to Detail 4 on sheet C0.3. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 78. [Stantec] For Construction Note #6, reference the roadside swale section in the detail sheets, in addition to S-130. WCE Response: Reference has been revised to Detail A on sheet C0.3 and Std Plan S-130. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 79. [Stantec] Label existing sidewalk to remain between STA's 15+00 and 17+00. WCE Response: Label with stations has been added. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 80. [Stantec] Construction Note #7 at STA 11+53.78 should reference a driveway approach with a separated sidewalk. See Standard Plans R-110 through R-112. WCE Response: Construction note 19 added to reference Std Plan R-110. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. Standard Plan R-113 with the adjacent sidewalk has been called out. As a driveway with separated sidewalk would not allow enough space to transition the 10ft, at 30 degrees, between the box culvert and the driveway. 81. [Stantec] Identify hextag #10 at each end of the existing sidewalk near STA 15+00 and 17+00. WCE Response: Hextag 10 added with stationing. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future City of Spokane Valley -Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 51 of89 comments for ease of review and response. 82. [Stantec] For the change in direction of the sidewalks near STA's 13+90, 14+75, and 16+75, please limit the maximum angle of change to 30 degrees. WCE Response: The angle has been revised to 30 degrees. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 83. [Stantec] For Construction Note #17, please locate the drywell near the low point. Maintain 5' of horizontal clearance from the nearest curb inlet. Verify that the drywell rim will be 0.25'minimum below the adjacent flowline elevation. WCE Response: The Catch Basin has been moved to the lowest pond level. ✓ [Stantec] Profile shows Top of Curb LT at Sta 12+93.40. Catch basin callout is located at Sta. 12+78.5, so this is not the low point of the swale. However, curb inlet is shown near 12+91 so flow gets to the drywell and swale will function as designed, maintaining minimum 5' of clearance from nearest inlet. Based on these parameters, the intent of the City's comment has been addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 84. [Stantec] Please provide stationing for all curb inlets. Limit maximum spacing of curb inlets to 100', or less depending on curb inlet calculations. Locate the curb inlets to maximize swale treatment. WCE Response: Curb inlet location table added to sheet C3. l 1 per note on this sheet. Spacing has been revised per 100 ft maximum and/or to maximize treatment. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 85. [Stantec] Roadside swales are considered flat for volume calculations where the swale bottom slope is 1 % or less. Address all roadside swales where the street grades exceed 1%. WCE Response: Check dams have been added where slope exceeds 1 %. See sheet C0.3 for check dam detail. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. City of Spokane Valley -S tantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 52 of89 WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. Sheet C3 .11 (Thorpe Road P &P) 86. [Stantec] See all applicable review comments from Sheet C3 .10 for this sheet. (77) For Construction Note #2, please reference Detail 4 on Sheet C0.3. WCE Response: Reference revised to Detail 4 on sheet C0.3. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. (78) [Stantec] For Construction Note #6, reference the roadside swale section in the detail sheets, in addition to S-130. WCE Response: Reference has been revised to Detail A on sheet C0.3 and Std Plan S-130. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 87. [Stantec] Please provide a Construction Note for the 6' wide sidewalk at the box culvert. WCE Response: Construction note 18 added for 6 ft sidewalk ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 88. [Stantec] Drainage easement to be labeled as permanent. WCE Response: Easement label has been revised. ✓ [Stantec] A review of the plans verifies that the intent City's comment has been adequately addressed. Labels do not say permanent, but they do not say temporary either. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 89. [Stantec] How will large debris lodged in the middle of the concrete channel get removed {say, at station 9+00)? Will equipment need to get down into the channel? If so, how? Provide access road and easement {include file number) along full City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 53 of89 length of channel? WCE Response: With the revised design, large debris that fits through the box culvert would flow strait through the open channel and would be pushed against the angled trash racks of the headwall as flood waters rise the debris would float/rise up the trash rack, thus clearing the inlet of debris. Additionally, a maintenance road and gate are placed above the headwall. With a mini-excavator any piled debris can be removed safely. See sheet C5.l for more detail. Per previous discussions, easements will be recorded and file numbers added after the CLOMR is received. ✓ [Stantec] A review of the plans verifies that the intent City's comment has been adequately addressed, with proposed trash rack and access to channel being provided. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 90. [Stantec] Please provide a curb inlet at low point STA 19+56.36 and near STA 22+75. Provide stationing for all curb inlets. Limit maximum spacing of curb inlets to 100', or less depending on curb inlet calculations. Locate the curb inlets to maximize swale treatment. WCE Response: Inlets have been added. Curb inlet location table added to sheet C3.1 l. Spacing has been revised per 100 ft maximum and/or to maximize treatment. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 91. [Stantec] For Construction Note #14 and the existing drywell to be abandoned, please specify that decommissioning drywells shall comply with WAC 173-218- 120 and WSDOT Specs 7-05.3 {2) Abandon Existing Manholes. The following is required: a. Remove any structure within three feet of the land surface, b. Backfill up to three feet below the land surface with material that is uncontaminated, chemically and biologically inert, and that drains equal to or more slowly than the native material surrounding the DIC well, and c. Fill the remaining three feet directly below the land surface with native soil or other structurally sound material common with CUITent engineering practices. WCE Response: Construction note revised and decommissioning notes added to sheet C3. l 1. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 54 of89 WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 92. [Stantec] For Construction Note #16, please provide Thorpe Road stationing and offsets for each catch basin for construction clarity. WCE Response: Construction note directs to sheet C5.l for location info. 0 [Stantec] In reviewing the plans, there is no Sheet C5.l. The note refers to Sheet CS.01, there is no Sheet C5.01 either. The detail appears to be on Sheet CS.IO, but there are no callouts for the catch basin and piping locations on the Box Culvert Detail. There are similar issue with Note 17. WCE Response: The plan set has been revised to establish a single reference. 93. In the Centerline/Sawcut Profile, please provide the missing grade break elevations for STA's 23+35.57 and 23+55.57. WCE Response: Grade break elevations have been added. ✓ A review of the plans verifies that the City's comment has been adequately addressed._ WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. The reference to Sawcut has been removed. Sheet C3.12 (Chester Creek Culve1t Extension) 94. [Stantec] Please revise the sheet title and Section 'A' title to match the Sheet Index on Sheet C0.0. WCE Response: Titles have been revised to match. ✓ [Stantec] A review of the plans verifies that the City's co1mnent has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 95. [Stantec] Please label Thorpe Road. WCE Response: Thorpe Road has been labeled. ✓ (Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 96. [Stantec] For Section 1, a. Verify the ROW/easement dimensions. Sheet C0.3 shows a ROW width of 55'. WCE Response: ROW width revised to show 55 feet. City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 55 of89 ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. b. Reference Std. Plan R-102 for the curb and gutter, WCE Response: Reference added to Std. Plan R-102. ✓ A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. c. [Stantec] Reference Std. Plan R-103 for the sidewalk, WCE Response: Reference added to Std. Plan R-103. ✓ [Stantec] A review of the plans verifies that the City's c01mnent has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. d. [Stantec] Specify how the curb and gutter will be secured to the precast panels, WCE Response: Curb and gutter will be doweled to the precast culvert sections. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. e. [Stantec] Set the top of sidewalk flush with the top of curb and gutter, WCE Response: Top of sidewalk revised to be flush with top of curb. ✓ [Stantec] WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. f. [Stantec] The 4" HMA is the minimum thickness, it will need to vary to get the cross-slope. WCE Response: Note revised for 4" min thickness and thickness varies to achieve cross slope. City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 56 of89 ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. g. [Stantec] Specify a tack coat shall be applied to the precast panel decking prior to placing the asphalt paving, WCE Response: Note added to tack coat prior to paving. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. h. [Stantec] Provide a guardrail at the north end of the box culvert extension. WCE Response: A guardrail has been called out on the north end of the box culvert extension. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 97. [Stantec] For Section 2, a. Provide construction details for the precast panel and footings i. How will precast panel be secured to the existing culvert? WCE Response: The panel has been revised to a precast box culvert and the details are provided on sheet C5.21. Shop drawings to be provided at time of construction. D [Stantec] In review of the plans, the box culvert detail is located on Sheet C5 .11, not CS .21. Otherwise, the city's comment is adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. The references have been revised 11. [Stantec] Footings need to be at or below elevation of existing culvert footings. WCE Response: Note added to install new footing at or below existing footings. b. [Stantec] Why is the FG@CL lower than the top of the precast panel? WCE Response: Section revised to show FG above culvert deck. ✓ [Stantec] A review of the plans verifies that the City's comment has City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 57 of89 been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. This note has been modified. Sheet C3.20 -C3.23 {Madison Road P&P) 98. [Stantec] In public meetings, street lights were promised along Madison Road. Please show the light locations and specify that the lights will be installed with the plat. Specify necessary conduit sleeves to be installed with the frontage improvements. WCE Response: Street lights have been added at the future street intersections. See construction note 19. • [Stantec] In reviewing the plans, street lights were added at the future street intersections, and notes were added to sheets. However, the location appears to be outside of the Madison Road ROW, and west of the intersections. The City will need to verify if the location of the future lights meets the intent of the request. WCE Response: So noted, a review of future Street Plans after the Public Hearing with the conditions set by the Hearing Examiner will determine the intent of the request, the original offer was intended to be street lights (30'+/-tall) with short 12' lights along the meandering trail for safety. Sheet C3.20 {Madison Road P&P) 99. [Stantec] See all applicable review comments from Sheet C3 .11 for this sheet. (78) For Construction Note #6, reference the roadside swale section in the detail sheets, in addition to S-130. WCE Response: Reference has been revised to Detail A on sheet C0.3 and Std Plan S-130. • [Stantec] In reviewing the plans, note refers to sheet C.03 (not C0.3), this typo is on remaining Madison Road sheets as well. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. The reference has been revised on all affected sheets. 100. [Stantec] Please provide stationing for all curb inlets. Limit maximum spacing of curb inlets to 100', or less depending on curb inlet calculations. Locate the curb inlets to maximize swale treatment. WCE Response: Curb inlet location table added to sheet C3.20. Spacing has been revised per 100 ft maximum and/or to maximize treatment. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 58 of89 comments for ease of review and response. 101. (Stantec] Roadside swales are considered flat for volume calculations where the swale bottom slope is 1 % or less. Address all roadside swales· where the street grades exceed 1%. WCE Response: Check dams have been added where slope exceeds 1 %. See sheet C0.3 for check dam detail. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 102. [Stantec] For Construction Note #9, utilities shall not be located in sidewalks per svss 6.2.2 &6.2.3. WCE Response: Construction note 9 has been revised to have utilities relocated outside of sidewalk. Relocation to be coordinated with utility company. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 103. [Stantec] Construction Note #14 -channel access may need to be shown for the full length of the channel. WCE Response: With the design change, channel access has been relocated to another sheet ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. Note has been changes to "Reserved". WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 104. [Stantec] Construction Note #16 at STA 10+75 should reference a driveway approach with a separated sidewalk. See Standard Plans R-110 through R-112. WCE Response: With the design change the driveway has been removed. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. Sheet C3.21 (Madi son Road P&P) 105. [Stantec] See all applicable review comments from Sheet C3.20 for this sheet. City of Spokane Valley -Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 59 of89 (78) For Construction Note #6, reference the roadside swale section in the detail sheets, in addition to S-130. WCE Response: Reference has been revised to Detail A on sheet C0.3 and Std Plan S-130. D [Stantec] In reviewing the plans, note refers to sheet C.03 (not C0.3). Similar reference errors throughout the plan set. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. the note has been revised. (100) [Stantec] Please provide stationing for all curb inlets. Limit maximum spacing of curb inlets to 100', or less depending on curb inlet calculations. Locate the curb inlets to maximize swale treatment. WCE Response: Curb inlet location table added to sheet C3.20 per note on this sheet. Spacing has been revised per 100 ft maximum and/or to maximize treatment. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. ( 101) [Stantec] Roadside swales are considered flat for volume calculations where the swale bottom slope is 1 % or less. Address all roadside swales where the street grades exceed 1 %. WCE Response: Not applicable on this section of Madison Rd as grades do not exceed 1 %. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. (102) [Stantec] For Construction Note #9, utilities shall not be located in sidewalks per SVSS 6.2.2 & 6.2.3. WCE Response: Construction Note 9 has been revised to have utilities relocated outside of sidewalk. Relocation to be coordinated with utility company. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 60 of89 Sheet C3 .22 (Madison Road P&P) 106. [Stantec] See all applicable review comments from Sheet C3.21 for this sheet. (78) For Construction Note #6, reference the roadside swale section in the detail sheets, in addition to S-130. WCE Response: Reference has been revised to Detail A on sheet C0.3 and Std Plan S-130. (100)[Stantec] Please provide stationing for all curb inlets. Limit maximum spacing of curb inlets to 100', or less depending on curb inlet calculations. Locate the curb inlets to maximize swale treatment. WCE Response: Curb inlet location table added to sheet C3.20 per note on this sheet. Spacing has been revised per 100 ft maximum and/or to maximize treatment. ( 101 )[Stantec] Roadside swales are considered flat for volume calculations where the swale bottom slope is 1 % or less. Address all roadside swales where the street grades exceed 1 %. WCE Response: Not applicable on this section of Madison Rd as grades do not exceed 1 %. (102)For Construction Note #9, utilities shall not be located in sidewalks per svss 6.2.2 & 6.2.3. WCE Response: Construction Note 9 has been revised to have utilities relocated outside of sidewalk. Relocation to be coordinated with utility company. D [Stantec] This sheet was not included in the submittal, verifications cannot be made on comments. It can be assumed that similar incorrect sheet references as indicated on prior and following sheets will apply to this sheet as well. WCE Response: Sheet C3.22 was submitted Separately to the City of Spokane Valley on August 24th 2018, WCE verifies comments as complete. Sheet C3.23 (Madison Road P &P) 107. [Stantec] See all applicable review comments from Sheet C3.22 for this sheet. (78) For Construction Note #6, reference the roadside swale section in the detail sheets, in addition to S-130. WCE Response: Reference has been revised to Detail A on sheet C0.3 and Std Plan S-130. D In reviewing the plans, note refers to sheet C.03 (not C0.3) WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. The reference has been revised on all affected sheets. WCE Response: So noted. The notes have been revised as appropriate on all affected sheets. (100)[Stantec] Please provide stationing for all curb inlets. Limit maximum City of Spokane Valley -Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 61 of89 spacing of curb inlets to 100', or less depending on curb inlet calculations. Locate the curb inlets to maximize swale treatment. WCE Response: Curb inlet location table added to sheet C3.20 per note on this sheet. Spacing has been revised per 100 ft maximum and/or to maximize treatment. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. Table is located on sheet C3.23. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. (101) [Stantec] Roadside swales are considered flat for volume calculations where the swale bottom slope is 1 % or less. Address all roadside swales where the street grades exceed I%. WCE Response: Not applicable on this section of Madison Rd. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. (102)[Stantec] For Construction Note #9, utilities shall not be located in sidewalks per SVSS 6.2.2 & 6.2.3. WCE Response: Construction Note 9 has been revised to have utilities relocated outside of sidewalk. Relocation to be coordinated with utility company. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 108. [Stantec] In public meetings, it was mentioned that the project sidewalk would extend and connect to the sidewalk by the school to the north. Please investigate. WCE Response: The sidewalk has been shown and called out to extend to the existing sidewalk to the north approximately 300'. The meandering path ends at the property line. A 5' walk has been called out per construction note 21. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 109. [Stantec] For the pedestrian ramp at the southwest corner of Madison Road City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 62 of89 and Road 'C', please connect the ramp to the 1 0' asphalt path. WCE Response: Ramp has been revised to connect to path ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. Sheet C3 .24 (Madison Road Storm Pipe Crossings) • [Stantec] This sheet appears to have been switched to sheet CS.22. It is incorrectly referred to throughout the plan set. It is also now called Madison RD Culvert Plan. WCE Response: So, noted, the Plan Set has been revised. 11 o. [Stantec] For Sections 'A' & 'C', provide a 0.10' min. drop through the catch basin per SRSM 8.5.2. WCE Response: A 0.1' drop has been added to the catch basins. D[Stantec] In review of the plans, catch basins do not appear to have a 0.1' drop. This is the case for all catch basins. WCE Response: For the type 1 catch basins a drop has been done where the flood design has not been compromised, however for the WSDOT Catch Basins as part a regional flood facility the inverts cannot be dropped by Stormwater standards. Nor can the inverts of the 18" pipes be lowered to match inverts as the pipes have a waterman flap, which would hold the flow from the Madison Hills till after the Chester Creek flow has passed. The inverts of the 18" pipes have been set at 0.3 ft above the 48" pipe invert. 111. [Stantec] For Sections 'C' & 'D', the soil cover over the culvert appears to be less than 1 '. SRSM 8.4.2 requires culverts with soil cover less than 2' to be ductile iron. Soil cover is measured from top of pipe to bottom of asphalt pavement. Increase the soil cover to 1' and provide pipe data supporting the shallow soil cover for a CMP material. WCE Response: The pipe has been revised to call out DI. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 112. [Stantec] Please specify the type of CMP. WCE Response: A note specifying the CMP has been added. WSDOT STD. 9- 05.1(2). ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 63 of89 WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 113. [Stantec] Provide trash racks at the inlets of all the cross-culverts since the outlet of the 60" pipe has a trash rack. WCE Response: Trash racks have been added. See sheet C3.24 for details. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. Details Sheets CS.10 and CS.30 114. [Stantec] Structures at the 60" RCP should be catch basins not manholes (per the narrative). Please show the sump. WCE Response: Manholes have been revised to catch basins with sumps. See construction note 3 on sheet CS .3. D [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. However, there is no Sheet CS.3. This could be referring to Note 3 on CS.20. It is incorrectly referred to throughout the plan set. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. The page references have been updated as needed. 115. [Stantec] Please revise the sheet title to match the Sheet Index on Sheet CO.O. WCE Response: The sheet title has been coordinated with the sheet index. D [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. However, Sheet C3.24 was switched to CS.22 and the references to this sheet needs to be updated throughout the plan set. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. The page references have been updated as needed. Sheet C3 .30 (Intersection Details) 116. [Stantec] For all details, label existing and proposed ROW's. WCE Response: Existing and proposed ROWs have been labeled. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 117. [Stantec] For the Curve Table, please specify that the data is taken at the back of City of Spokane Valley -Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 64 of89 curb. WCE Response: A note has been added to this affect. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 118. [Stantec] For Detail 1: a. Provide a widened border easement per SVMC 20.20.090, WCE Response: The border easements have been revised ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. b. [Stantec] Provide curve data and spot elevations for the south edge of pavement, WCE Response: A radius length and spot elevations have been added. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. c. [Stantec] Adjust the separated sidewalk location to the back of the ramp, WCE Response: The sidewalk has been revised to meet the back of the ramp. ✓ [Stantec] WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. d. [Stantec] Label the gutter slope at the base of the ramp. WCE Response: The gutter slope has been labeled. • [Stantec] In reviewing the plans, the gutter slope is labeled on both sides of the base of the ramp, but the base of the ramp is not labeled. The TP elevations labeled at the base of the ramp indicate a slope of 6.0%. Max slope at the base of the ramp should be 2% or less. • New Comment: Thorpe is mis-spelled (Thopre) in Details 1 and 2. WCE Response: The gutter slopes at the curb ramps have been revised and, the spelling of Thorpe has been corrected, please note that at the ramp the grade will be City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 65 of89 forced to a 2% slope for ADA. 119. [Stantec] For Detail 2: a. Rename 'Dishman-Mica Road' to 'Madison Road', WCE Response: The road name has been revised. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. b. [Stantec] Provide a widened border easement per SVMC 20.20.090, WCE Response: The border easements have been revised ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. c. [Stantec] Revise the BCR top of curb spot elevation on Thorpe Rd to match the profile, WCE Response: The BCR has been revised to match the road profile. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. d. [Stantec] Verify that the gutter slope at the base of the pedestrian ramp is 2% or less. WCE Response: The gutter slope has been labeled and a max of 2% slope in front of the pedestrian ramp has been called out. ✓ [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. Max slope of 2% is not called out. However, the gutter slope is 1.16%, meeting the intent. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 120. [Stantec] For Details 3-6: a. Revise the BCR top of curb spot elevations on Madison Rd to match the profile, WCE Response: The BCRs have been revised to match the profile. ✓ [Stantec] A review of the plans verifies that the City's comment has been City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 66 of89 adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. b. [Stantec] Verify that the gutter slopes at the base of the pedestrian ramps and the cross-slope along the crosswalk are 2% or less, WCE Response: The gutter slope has been labeled and a max of 2% slope in front of the pedestrian ramp has been called out. • [Stantec] In reviewing the plans, the gutter slope is labeled on both sides of the base of the ramp, but the base of ramp is not labeled. In detail 2, the TP elevations labeled at the base of the ramp indicate slopes of 17%+ at base of ramps. Max slope at the base of the ramp should 2% or less per SP R-107. WCE Response: The gutter slope at the curb ramps have been revised. c. [Stantec] The longitudinal slope of Madison Rd at each intersection is less than 0.8%. Adjust the Madison Rd BCR top of curb spot elevations to create a 0.80% minimum longitudinal slope without a cross gutter or a 0.50% minimum longitudinal slope with a cross gutter (SVSS 7.5.4) or lower the BCR spot elevations on Roads 'A' -'D' so the intersections slope to the west. WCE Response: The elevations have been kept so that water flows around the intersections to the east and will enter the roadside swales for treatment. • [Stantec] In reviewing the plans, Details 5 and 6 do not provide a 0.50% minimum longitudinal slope on the southwest curb returns. WCE Response: The gutter slope at the curb ramps have been revised. 121 . [Stantec] For Detail 7: a. Verify that the gutter slope at the base of the pedestrian ramps and along the cross walk are 2% or less, WCE Response: The gutter slope has been labeled and a max of 2% slope in front of the pedestrian ramp has been called out. • [Stantec] In reviewing the plans, Details 7 provides a max of 2 % slope. However, the southeast curb return does not provide a 0.50% minimum longitudinal slope. WCE Response: The gutter slope at the curb ramps have been revised. b. [Stantec] Provide the future design of Road 'E', provide curb inlets on Road 'E' at the east BCR's. WCE Response: See sheet C3.03 for the plan and profile of Sundown Rd (Road E). Type 2 curb inlets have been called out on the east BCRs. • [Stantec] In reviewing the plans, this is not the case. Top of Curb elevations are not labeled on Sheet C3.03. However, the intersection design indicates flow goes City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 67 of89 to the east around the curb returns to Sundown. Sundown flows toward the west to the same location. There are no curb inlets at this low spot indicated on the plans for the east BCRs. WCE Response: The gutter slope at the curb ramps have been revised, Note the low point of Sundown falls within the future street section, therefore a temporary pond is called out to capture any small amounts of storm water. Type 2 will be included at the PCR's during subdivision design. For Items 122 through 146 the Levee has been removed from the flood control plan including the referenced sheets WCE Verifies Items 122 through 146 as Complete Sheet C4.0 (Grading Plan) • [Stantec] It is unclear what the intent of this sheet is, as nothing is identified outside of overall quantities. WCE Response: the overall quantities and global reference is the intent of the sheet. A fill specification has also been added to this sheet by other comment, lot grading in accordance with future BFE's etc. show lots I+ feet to 2+ feet above streets, etc ... Sheet C5.0 (Storm System Overview) 147. [Stantec] Include titles for profiles. WCE Response: Titles have been added to the profiles. D [Stantec] In reviewing the plans, there is only one profile. Title is not shown. In addition, none ofthe sheet callouts are correct on this sheet. Sheets C5.1 to C5.5 do not exist. WCE Response: Titles have been shown for applicable viewports. The callouts have been revised to call out the correct references. 148. [Stantec] For upper profile provide stations for all structures. WCE Response: Stationing has been added for structures. • [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. There is only one profile, structures have stations. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 149. [Stantec] Construction Notes: a. Provide all applicable details sheets for all notes. WCE Response: The brief construction notes have been removed since the sheet is intended as an overview of the flood system. Detailed construction notes are on the storm sheets following C5.0. City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 68 of89 D [Stantec] In reviewing the plans, there are no construction notes on this sheet. Construction notes are on CS.20 and CS.21. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. b. [Stantec] Note 5 -"manhole" should be "catch basin". Revise standard plan callout and specify depth of sump. Check spelling of "labelled". WCE Response: The construction notes have been removed but where this item shows up on other sheets, the notes have been revised to indicate WSDOT catch basins with 2-foot sumps. D [Stantec] In reviewing the plans, there are no construction notes on this sheet. However, sheets with construction notes have Catch basins labeled in notes (Sheets CS.20 andC5.21). WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. Sheet C5. l(Concrete Channel P&P) D [Stantec] In reviewing the plans, this appears to now be Sheet CS. I 0, and it is now called Box Culvert-Channel-Pipe Plan 150. [Stantec] Plan View: a. Invert elevation of pipe from SD-CB #1 at the channel wall doesn't match the elevation in CS.2. Please verify the pipe slope from SD-CB#l to the concrete channel. WCE Response: !E's have been verified. D [Stantec] In reviewing the plans, this is now shown on sheet CS.20. Pipe slopes are labeled 0.0025. Calculating slopes based on box culvert to CDCB #1 inverts (2007.18 and 2006.05) over 451.40', slope is .0027. WCE Response: The Pipe slopes have been verified with the revision to the pipes. b. (Stantec] Include the 100-year stormflow in the system cal cs from the pipes originating from SD-CB #1 and SD-CB #2. WCE Response: The peak for the flow through the catch basins will occur much sooner than the peak for the channel flow, therefore, the catch basin flows have not been included. D [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. c. [Stantec] Show the fence located north of the channel in cross section A. City of Spokane Valley -Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 69 of89 WCE Response: The fence has been added. D [Stantec] A review of the plans verifies that the City's comment has been adequately addressed, the detail being referenced is now Detail 4. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 151. [Stantec] Construction Notes: a. Note 1 -include C5.21 WCE Response: Note revised to include C5.21. D [Stantec] In reviewing the plans, this no longer appears to be applicable on this sheet. However, Sheet C5.20 has headwall referenced to Sheet C5.l, should be Sheet C5.10. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. b. Note 4 -include S-121 WCE Response: Note revised to include C-121. D [Stantec] In reviewing the plans, this no longer appears to be applicable on this sheet. However, Note 4 on sheet C5.20 references 18" culvert with rubber gasket indicates see sheet C5.22 for details. Which has a rubber gasket detail. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. the rubber gasket has been removed from the note. 152. [Stantec] Profile - a. Include slope down to culvert inlet. WCE Response: See revised slope callout on sheet C5.l D [Stantec] In reviewing the plans, this no longer appears to be applicable on this sheet. Slope is provided on sheet C5.20 WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. b. [Stantec] Check stationing on axis. WCE Response: Stationing has been verified. D [Stantec] In reviewing the plans, this no longer appears to be applicable on this sheet. Again, this applies to sheet C5.20 and appears to have been addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. City of Spokane Valley -Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 70 of89 153. [Stantec] Please provide structural calculations and details for the fence, retaining walls and footings in Section 'A' (loads, dimensions, reinforcing, connections, etc.). WCE Response: See sheet C6.0 and C6. l for structural details for retaining walls and footings. See separate package for calculations. • [Stantec] In reviewing the plans, structural details are provided. A separate review of these details and calculations from a licensed structural engineer is recommended. WCE Response: Sheets C6.0 through C6.2 Structural Details have been revised and a Structural Calculation package has been prepared and attached to this letter. Sheet C5 .2 (Box Culvert and Channe·1 Details) • [Stantec] In reviewing the Plans, this also appears to be Sheet C5 .10 • [Stantec] New comment, there are many callouts to sheets that no longer exist or that have been changed. WCE Response: Callouts have been verified and revised as needed. 154. [Stantec] Box Culvert Detail: a. General -Provide design details for box culvert and wing wall ( design loading, dimensions, elevations, thickness, reinforcing, connections, etc.) WCE Response: See note 2. The contractor will supply shop drawings and design calculations when they pick a supplier of the pre-cast structure. • [Stantec] The city will need to decide if this approach is an acceptable solunon. WCE Response: As the box culverts are a custom build and meet HS-20 or HS 25 design loads the supplier will not provide shop drawings until the project has been approved, through the public hearing process. We would expect a condition from the Hearing examiner or FEIS process. b. [Stantec] Plan View - i. Drainage easement is permanent not temporary, WCE Response: The note has been revised. D A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. ii. For culvert alignment line provide a bearing and a station equation where this alignment crosses the Thorpe alignment WCE Response: See sheet C5.1 for bearing and station equation. D [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. Although there is no sheet C5. l, this is on Sheet C5.10. City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 71 of89 WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. iii. [Stantec] Check stationing of wing walls. WCE Response: Stationing of wing walls are from the culvert alignment and not Thorpe Rd and have been verified. 0 [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. c. [Stantec] Section 1- i. Label the ROW WCE Response: The ROW has been labeled. 0 [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. ii. [Stantec] Reference Std. Plan R-102 for the curb and gutter, WCE Response: Standard plan R-102 has been referenced. • [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. iii. [Stantec] Reference Std. Plan R-103 for the sidewalk, WCE Response: Standard plan R-103 has been referenced. D [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. iv. [Stantec] Specify how the north curb and the south curb and gutter will be secured to the precast panels, WCE Response: The curb and gutter will be cast onto the deck with dowels epoxied into the deck. The curb will be cast into the box section per the detail on C5.10. 0 [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 72 of89 WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. v. [Stantec] Set the top of sidewalk flush with the top of curb and gutter, WCE Response: The top of sidewalk has been set flush with the top of curb and gutter. • [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. vi. [Stantec] Specify a tack coat shall be applied to the precast panel decking prior to placing the asphalt paving, WCE Response: A note specifying a tack coat shall be applied has been added. • [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. vii. [Stantec] Provide guardrails at both ends of the box culvert. WCE Response: A guardrail at the south end of the box culvert has been provided. On the north end of the culvert there is a 7.5' sidewalk and there will also be a 6' chain-link fence for channel access control. There is no room to place a guardrail with these limitations. • [Stantec] A review of the plans verifies that the City's comment has been adequately addressed if the city agrees with WCE Response. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. viii. [Stantec] Adjust the 12' dimension to start at the face of the 6" curb. WCE Response: The dimension has been revised to 14.5 feet to accommodate standard precast box sections. • [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. ix. [Stantec] Verify the precast panel deck thickness with Section 2. WCE Response: The thickness has been revised so sections 1 and 2 match at 1.5 feet. City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 73 of89 0 [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. x. [Stantec] The 4" HMA is the minimum thickness, it will need to vary to get the cross-slope. WCE Response: A note has been added specifying a varying thickness. D [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. xi. [Stantec] For slope down into the culvert inlet - 1. What is the stormwater velocity? WCE Response: Per the Capacity calculation of the box culvert, at a depth of 2 feet and an area of 56.66 sf the velocity of 216.4 cfs (which is twice the 100-year storm rate) has a projected velocity of 3.82 ft per second. Per Open Channel Hydraulics, Chow section 7-9 The Maximum Permissible Velocity Figure 7-3 of the U.S.S.R. Data shows that a 200 mm or 8" particle or rock surface can withstand a velocity of 13 ft per second+/-before scour occurs. D [Stantec] A review of the provided documents verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 2. [Stantec] Is erosion protection needed? WCE Response: Erosion protection has been added. 1 '-2' angular rip-rap 3' deep has been called out. The erosion protection extends up the slope to the right-of-way. Based upon the information of item 1 with the erosion protection there is no scour anticipated. D [Stantec] A review of the provided documents verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. d. [Stantec] Section 2 -bottom of box is alluvial bed. Calculate scour and set footings below scour. WCE Response: The bottom of the box is rocked as well as the approach within City of Spokane Valley -Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 74 of89 the ROW. See response above. • [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 155. [Stantec] Channel and Pipe Connection: a. General -Provide design details for channel and trash rack (loads, dimensions, reinforcing, connections, etc.) WCE Response: Structural details have been provided on sheet C6.0 and C6.1. Trash rack details have been provided on sheet C5.6. • [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. b. [Stantec] Plan View - i. There are two set of lines where the channel turns, remove lines that do not represent the channel geometry. WCE Response: The line has been removed and the channel has been hatched to more clearly show where the channel bottom is. ii. [Stantec] Provide channel alignment details and location of pipe inlet. WCE Response: The alignment location in the channel bottom is centered iii. [Stantec] Drainage easement is permanent not temporary, WCE Response: The drainage easement label has been revised. • [Stantec] A review of the plans verifies that the City's comment has been adequately addressed._ WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. Sheet C5.3 (Madison Pipe P&P) • [Stantec] This is now Sheet C5.20 WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. D [Stantec] In review of the plans, many sheet and detail callouts are incorrect because of the sheet numbering\naming change, continuous issue throughout the plan set. WCE Response: The sheets and callouts have been revised throughout, we will continue to verify up to the start of construction. City of Spokane Valley -Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 75 of89 156. [Stantec] Construction Notes: a. Note 3 -Structures at the 60" RCP should be catch basins not manholes (per the narrative}. Call out standard plan for catch basins and specify depth of sump. WCE Response: Note revised to catch basins with 2 ft sump. • [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. b. [Stantec] Note 5 -is the concrete outlet a pad or slab (see C5.4)? WCE Response: Construction note 4 on sheet C5.3 revised to pad. • [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. Take into account that all sheets being referenced are incorrect, the note is on SheetC5.21. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response., Details on sheet CS.3, and Sheets C6.0 to C6.2 c. Note 7 -specify frame and grate type and include S-121 reference. WCE Response: Construction note 7 has been revised to include Type 1 Frame and Grate and to reference SVSS S-121. • A review of the plans verifies that the City's comment has been adequately addressed. Take into account that all sheets being referenced are incorrect, the note is on SheetC5.21. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 157. Plan view: a. Make sure all structures are accessible for cleaning and have a construction note, WCE Response: Meandering path to be used for access. • [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. b. [Stantec] In 60" pipe why is there a structure at 22+45? WCE Response: The pipes and structures have been revised. • [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 76 of89 WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 158. [Stantec] Profile: a. Provide stations for all structures on concrete pipe, WCE Response: Stationing has been provided for all structures. • [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. b. [Stantec] Make sure all pipes have length and slope information, WCE Response: Pipe information has been verified for all pipes. u [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. c. [Stantec] Provide offset at 60" pipe outlet. WCE Response: A station and offset from Madison Rd has been provided. '.J [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 159. [Stantec] For the culverts under Madison Road, Spokane County GIS shows that there may be a 24" pipe near station 23+50. Please check. WCE Response: All Madison Rd culverts have been surveyed and verified with no evidence of a 24" culvert. D [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 160. [Stantec] Include the 100-year stormflow in the system calcs from the pipe originating from SD-CB #6. WCE Response: The 100-year flood has been added, please see the flood control narrative D [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 77 of89 WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. Sheet C5.4 (B ioswale P&P) • [Stantec] This is now Sheet C5.30 (Bioswale/Settling Pond P&P WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. • [Stantec] In review of the plans, many sheet and detail callouts are incorrect because of the sheet numbering\naming changes, continuous issue throughout the plan set. WCE Response: The sheets and callouts have been revised throughout. 161. [Stantec] Include a short wall at the downstream end of the bioswale as a last trap for sediment. WCE Response: The design has been revised to include al' deep settling pond at the bottom of the bioswale, with a 20' wide rock weir overflow into a 2' deep infiltration pond with a field of drywells set at l' above the pond surface. This is the design that prevents sediment from entering the gravel gallery. • [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. the rock weir has been revised to be 2 48" pipes see Sheet CS.32 for a profile of the pipes. 162. [Stantec] Plan View: a. Clean up overlapping info, WCE Response: Labels have been revised. • [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. b. [Stantec] Provide dimensions/alignment/geometry information for fence, channel and pipes to locate them in space. WCE Response: Station and offset has been provided to Madison Rd to give reference of location in space. • [Stantec] In reviewing the plans, the alignment for the bioswale needs horizontal reference information (PCs, PTs, and Curve data). WCE Response: an alignment has been provided, with PCs, PTs. Line and curve tables City of Spokane Valley -Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 78 of89 have also been provided. • [Stantec] 15' access roads (locations and elevations) are not defined. WCE Response: A 15' wide access road has been called out. • [Stantec] Locations of drainfield pipes, structures, and limits of drywell rock are not defined. WCE Response: the gallery/drainfield has been removed from the design. Each drywell will be standalone per City of Spokane Valley Standard Plan. A Detail and location table is shown on Sheet CS.32. • [Stantec] Fence location is not defined. WCE Response: the fence is called out to be installed within the top of the headwall and along the Madison Rd pathway, within the shoulder. c. Confinn all structures can be accessed for maintenance. WCE Response: An access maintenance road has been provided. • [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. d. [Stantec] Provide all dimensions for hammerhead tum around. WCE Response: Dimensions have been provided. • [Stantec] There does appear to be a hammerhead tum around. 15' access roads (locations and elevations) are not defined. WCE Response: the hammerhead turn around has been removed from the design. e. [Stantec] Provide file number for easement. WCE Response: Space has been provided for inserting file number once easement is recorded after receipt of CLOMR-F comments prior to LOMR submittal per our discussions. • [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 163. [Stantec] Construction Notes: City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 79 of89 a. Make sure all notes have pertinent detail sheets referenced. WCE Response: Verified. O[Stantec] There are references to Detail B that does not exist on Sheets C5.31 and C5.32. WCE Response: Detail B has been removed D [Stantec] Detail A has seed mix reference to a sheet that does not exist. WCE Response Seed mix reference has been verified on Sheet CS.31 b. [Stantec] Note 3 -gate should be wider than road. WCE Response: Double swing gate width has been revised and is called out to be 16'. D [Stantec] In reviewing the plans, double swing gate does not appear be called out and it is not evident where the gate is located. WCE Response: The gate has been added West of the pipe crossing. c. (Stantec] Note 9 -specify frame and grate type and include S-121. WCE Response: Construction note 9 has been revised to include Type 1 Frame and Grate and to reference SVSS S-121. D [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. However, this is note 6. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. d. [Stantec] Include note for infiltration head wall. WCE Response: The infiltration headwall has been removed from the design D [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 164. [Stantec] Bioswale Inlet Cross Section: a. Provide design details ( dimensions, elevations, thickness, reinforcing, connections, etc.). WCE Response: See sheet C6.0 and C6.lfor structural details. D [Stantec] Structural details are provided on these sheets. It is recommended structural calculations and details be reviewed by a licensed structural engineer. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. A structural calculation package has been City of Spokane Valley -Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 80 of89 provided with this submittal and is in the appendix to this response. b. [Stantec] Provide details for trash rack. WCE Response: See sheet C5.3 for trash rack details. ::J [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. Although these are located on Sheet C5.30. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. c. [Stantec] In upper drawing check the orientation of the section arrows. WCE Response: Revised. • [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. d. (Stantec] Include the concrete level spreader in the hydraulic cal cs. WCE Response: The level spreader has been added to the west consultants' calculations. • [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 165. [Stantec] Typical Bioswale Section A a. Call out minimum depth of section. WCE Response: The minimum7 foot depth of the section has been added. • [Stantec] Minimum depth of section is noted as 6' to bottom of treatment soil for this section. Treatment soil is identified as 1.5' deep, indicating 4.5' of depth to bottom of swale. If 7' is the intended minimum depth of the bioswale, it is not identified correctly. WCE Response: the minimum depth is 6-ft from top of slope to swale Bottom with 2:1 side slope. b. [Stantec] The O&M manual says the side slopes are 3: I, please correct. WCE Response: Manual has been revised to 2: 1 side slopes. D [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 81 of89 166. [Stantec] Narrative says bioswale will be seeded not sodded, please revise. WCE Response: Note revised to seed the bio-swale. • [Stantec] Note to be seeded was added, but it is referring to a seed mix on a sheet that does not exist. WCE Response: The Seed Note is referenced as sheet C5.31 167. [Stantec] Profile -show proposed grade. WCE Response: The proposed grade of 1.00% has been added. 0 A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 168. [Stantec] Include the 100-year stonnflow in the system calcs from the pipe originating from SD-CB #7. WCE Response: The peak for the flow through the catch basin will occur much sooner than the peak for the mainline flow, therefore, the catch basin flow has not been included. • [Stantec] A review of the plans verifies that the City's comment has been adequately addressed._ WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. Sheet C5.5 (Infiltration P&P) • [Stantec] This sheet is now broken up into Sheets C5.31 and CS.32. WCE Response: So noted. • [Stantec] Construction notes refer to a Detail B, that does not exist. They also refer to Section C on the incorrect sheet. WCE Response: Construction notes have been revised. • [Stantec] References on previous sheets have not been updated to reflect new sheet numbers and details. WCE Response: The plan set notes and references have been revised throughout, we continue to check and double check, it should be expected that with the many sheet revisions most if not all have been revised. The remaining will be corrected as found. 169. [Stantec] Plan View: a. Provide alignment information for pipes and structures to locate them in City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 82 of89 space. WCE Response: Station and offset of Madison Rd has been provided at comers to locate them in space. D [Stantec] This only shows location of pond bottom, not structures within the pond. Locations of pipes and structures are not adequately identified within the drainfield. WCE Response: the gallery/drainfield has been removed from the design. Each drywell will be standalone per City of Spokane Valley Standard Plan. A Detail and location table is shown on Sheet CS.32. b. [Stantec] Confinn all structures - i. Have rim and inlet elevations and that elevations match those in profile WCE Response: Rim and invert elevations have revised and verified. (] [Stantec] Invert elevations are not noted anywhere in plan or profile. WCE Response pipes within drainfield have been removed from this design. • [Stantec] Detail Fon Sheet C5.32 has pond bottom noted at 1996.8. Infiltration pond notes indicate a bottom elevation of 1995.80 and minimum berm elevation of 2002.80 (7' depth). Typical sections shown 6' minimum from top of berm to bottom of treatment soil. Together, this information would make a depth of 4.5'. Overall, there is no consistency in callouts and the intended design is unclear. WCE Response: Detail F has been removed from the design, Detail D depth matches difference in pond bottom and min Berm Elevation within biofiltration Pond data Table on C5.31 • [Stantec] Section Fon sheet C5.32 shows both Drywell Rims and Pond Bottoms to be 1996.80, with 1.0' between them. Notes indicate pond bottom of 1995.8. It is not clear which one is correct. ii. Can be accessed for maintenance (especially by Vactor per the project narrative). WCE Response: Distance has been verified. • [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. c. [Stantec] Provide structure numbers to relate structures to those in the profile. WCE Response: Structure numbers have been provided in plan and profile views. • [Stantec] Structure numbers are not provided in plan or profile. City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 83 of89 WCE Response: Detail F has been removed from the design, Drywell number have been added to the plan view and the locations are provided on Sheet CS.32 d. [Stantec] Provide file number for easement. WCE Response: Space has been provided for inserting file number once easement is recorded after receipt of CLOMR-F comments prior to LOMR submittal per our discussions. • [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 170. [Stantec] Profile: • [Stantec] Typical sections are used in lieu of plan and profiles. This is acceptable if a reference location is provided to each row of drywells. a. Provide stations at structures. WCE Response: Stationing has been provided for structures. • [Stantec] Stations are not provided. As noted above, a reference location could be used in lieu of stationing, if one was provided. WCE Response: Detail F has been removed from the design, Drywell number have been added to the plan view and the locations are provided on Sheet CS.32 b. [Stantec] Show proposed grade. WCE Response: The proposed grade matches existing grade. • [Stantec] It appears that it is the existing grade that is not shown, rather than proposed. Unless this pond already exists and happens to be at the exact location as the proposed cross-section throughout the entire pond. WCE Response: Detail F has been removed from the design. 171. [Stantec] Construction Notes: a . Make sure all notes have pertinent detail sheets and standard plans referenced. WCE Response: Notes and references have been verified. • [Stantec] Notes refer to sections that do not exist as well to details on incorrect pages; some are not even called out. WCE Response: Detail F has been removed from the design. b. [Stantec] Note 7 -specify drywell type. City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 84 of89 WCE Response: The drywells are per City of Spokane Valley standards with additional barrels to achieve added depth. • [Stantec] Tripe Depth Drywell per COSV Standard plan S-101 is referenced. Type 'B" drywells only go to double depth in S-101, so this is not a standard drywell installation. In addition, these are quadruple depth because the of the added section for perforated pipe and extended gravel gallery at the bottom of the drywells. Additional detail is required for drywell installing. WCE Response: Detail F has been removed from the design. c. [Stantec] Note 8 -specify fabric class. WCE Response: The fabric class has been specified. D [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. It is called out in the standard plan reference. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. d. [Stantec] Note 9 -provide standard plan. D [Stantec] Note 9 does no longer exists, it is not known which note this would be referring to, therefore which standard it should call out. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. e . [Stantec] Include note for infiltration head wall. WCE Response: The infiltration headwall has been removed from the design. D [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 0 [Stantec] New comment. The City is concerned about the erodability of fill due to the very large volume proposed for fill material, and its proximity to flood plain areas between the proposed alignment of 43rd Street and Painted Hills Street. The entire set of submittal documents has been scanned for mention of a fill specification for the material to be used to construct embankments and particularly roadway embankments throughout the project site. No mention was found. Please provide. WCE Response: A fill specification has been placed on Sheet C4.0. with a minimum of 92% compaction density, and the requirement that all material from offsite be able to meet the same specification per the Geotechnical engineer. City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 85 of89 Sheet C6.6 (Infiltration Headwall Details) 172. [Stantec] Provide design details for headwall, channel and trash rack (loads, dimensions, elevations, thickness, reinforcing, connections, angle!l, etc.). 173. [Stantec] Call out spacing between pipes. 174. [Stantec] Provide stations at end of channel and at pipe inverts. WCE Response: The infiltration Headwall has been removed from the design. D [Stantec] A review of the plans verifies that the City's comment has been adequately addressed._ WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. Sheet C6. 7 (Infiltration HeadwaU Details) 175. [Stantec] Drain field cross section -provide complete spec reference. 176. [Stantec] 24" HOPE Cross Detail -specify filter fabric and how it is attached to pipe. WCE Response: The design has been revised. D [Stantec] A review of the plans verifies that the City's comment has been adequately addressed._ WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. (Now sheet C6.2) Sheet C9.0 (SWPPP Cove1·) 177. [Stantec] Legend -there isn't a storm drain pond, please revise. WCE Response: "Pond" revised to "facility" as we don't want washout at the bio- swale. '.J [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. 178. [Stantec] Provide protection at infiltration headwall. WCE Response: Protection at the infiltration headwall has been added. D [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. Sheets C9.0 (SWPPP Cover) 179. [Stantec] Legend -there isn't a sto1m drain pond, please revise. WCE Response: "Pond" revised to "facility" as we don't want washout at the bio- City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 86 of89 swale. • [Stantec] A review of the plans verifies that the City's comment has been adequately addressed. WCE Verifies Comment as Complete, please remove this completed item from future comments for ease of review and response. Sheets Cl0.0 to Cl0.2 (Signing and striping plans) • [Stantec] New Comments: These are added sheets to the plan. Based on a review of signing and striping plans: Below are items of note. • [Stantec] MUTCD standards should be identified in addition to any Spokane Valley Standard plans identified. WCE Response: A cover sheet has been provided with the WCE General notes -Traffic Signal, Channelization &. Stripping. Within the general notes are all references to MUTCD, WSDOT, and City of Spokane Valley standards where applicable. • [Stantec] Per COSV Street Standards 4.10: TEMPORARY TRAFFIC CONTROL PLAN: A temporary traffic control plan shall be included with the right-of-way permit. The plan shall be in detail appropriate to the complexity of the project per MlJTCD Chapter 6 B. o Comment: This will be required prior to issuing permit for work within public right-of-way. WCE Response: So Noted, a traffic control plan submitted by the contractor shall be submitted at the time of right-of-way permit. D [Stantec] Per COSV Street Standards 4.11.3 SIGNING PLAN: D [Stantec] The permanent signing plan shall: Show the longitudinal location of each sign (horizontal offset and station) o Comment: Only station has been noted, offsets are not provided in plan set. WCE Response: So noted, stations and offsets have been provided for all signs shown on plan. • [Stantec] Specify the sign legend and sign type (from MlJTCD and International Fire Code); o Comment: Street name signs are not indicated in the plan set ( existing or proposed). WCE Response: Street names for existing roadways have been called out on the sheet specific to that street in this case sheet Cl0.2 Thorpe Road. Future street channelization and signing plans will provide, street name signs during the creation of those public streets. City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 87 of89 • [Stantec] Specify the sign size and applicable standard plan; o Comment: Sign sizes are not indicated in the plans. WCE Response: So noted. Please see the sign details on each sheet. The sign sizes are listed below the MUTCD sign label. • [Stantec] Refer to Standard Plan R-140 for post and base dimensions and installation plan; o Comment: This is not noted in the plans. WCE Response: Standard Plan R-140 has been referenced in the plans. • [Stantec] Specify the blank gauge of the sign; and, o Comment: This is not noted in the plans. WCE Response: this specification is provided from MUTCD and WSDOT standards were applicable, See WCE General Notes -Traffic signals, Channelization, & Signing for the reference to these standards. • [Stantec] Note the reflectorization provided. o Comment: This is not noted in the plans. WCE Response: this specification is provided from MUTCD and WSDOT standards were applicable, See WCE General Notes -Traffic signals, Channelization, & Signing for the reference to these standards. D [Stantec] Per COSY Street Standards 4.11.4 STRIPING PLAN: • [Stantec] The striping plan shall show: Color and type; Lane widths, taper lengths, storage lengths, etc.; Striping/skip interval; o Comment: Lane widths are not provided on sheet Cl0.2 WCE Response: Existing and proposed lane widths are called out for each road section. • [Stantec] Any construction or application notes, (e.g., application temperatures, surface cleaning methods to be used prior to application, etc.); o Comment: Not addressed in plan set. WCE Response: this specification is provided from MUTCD and WSDOT standards were applicable, See WCE General Notes -Traffic signals, Channelization, & Signing for the reference to these standards. • [Stantec] Typical treatments for acceleration/deceleration lanes, turning lanes, and crosswalks; o Comment: Not addressed in plan set. City of Spokane Valley -Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 88 of89 WCE Response: Treatments for lanes, and turning lanes are typical of the WSDOT standard plans called out. Storage lengths and taper Rates reference the WSDOT design manual. D [Stantec] Station and offset or dimensions to all angle points, symbol locations, and line terminations. o Comment: Offsets not identified in plan set. Radii needs to be identified for all radial transitions. WCE Response: Offsets are provided and Radii within radial tapers are called out. 6 CLO MR APPLICATION (West Consultants) The City's comment as of 8/20/18: "The CLO MR Application has been revised since the City's rejection of the Levee Design. A CLOMR-F application has been provided." The application has been further revised to a CLOMR Application, recognizing the proposed flood plain alteration. References to a CLOMR-F has been deleted. WEST Response: all references to a CLOMR-F have been removed 6.1 NARRATIVE 180. Page 9 & page 14 paragraph 1-mentions that the infiltration facility maximum design flow is 84 cfs. Where was that flow rate obtained? 181 . Page 13, end of 2nd paragraph -may want to also reference the Geotech investigation for the latest drywell design which is the document titled "Full-Scale Drywell Testing ... ". 182. Please include page numbers for all the narrative's pages. HEC-RAS model 183. Proposed Madison concrete pipe is initially 4 feet in diameter then goes to 5 feet in diameter but the second pipe in the model is 6 feet in diameter, please revise and update the text in the narrative. 184. At the outlet of the 5-foot pipe include the concrete level spreader (sheet C5.4). D The above comments have been superseded by a detailed review of the updated CLOMR Application. All the above comments are either no longer relevant or they have been addressed. 6.2 FORMS 185. Riverine Strnctures Form -does the new culvert under Thorpe need to be included in one of the C. BRIDGE/CULVERT sections? • A Riverine Strnctures Form has been included in the revised CLOMR submittal, including hydraulic analyses of the box culvert proposed under Thorpe Road; the culvert at Highway 27 for the entry to the proposed pipe in the Gustin Ditch, and the concrete channel at the golf course. City of Spokane Valley-Stantec Painted Hills-Flood Control -Response Letter June 29, 2020 Page 89 of89 Appendix 1. BSW-Clarification Letter 2. Flood Vs. Pond Storage Comparison 263 HR Storm 3. Results of Subsurface Exploration and Infiltration Testing 4. Results of Infiltration Testing 5. Structural Calculations Chad W. Coles, P.E. – Director / County Engineer 1026 West Broadway Avenue  Spokane, WA 99260-0170 Phone: (509) 477-3600  Fax: (509) 477-7655  TDD: (509) 477-7133 www.spokanecounty.org Lori Barlow, AICP, Senior Planner City of Spokane Valley 10210 East Sprague Avenue, Spokane Valley, WA 99206 Dear Ms. Barlow, Spokane County Public Works submits the following comments relative to Floodplain and Stormwater issues for the EIS for the proposed Painted Hills PRD: 1.Off-Site Proposal: We are concerned with the overall lack of detail and clarity on offsite proposal in Spokane County and with addressing of the associated impacts. Suggest maps/plans specifically to address the offsite areas. Also, the Biological Report and Cultural Resource Survey do not appear to address off site project area at all. 2.CLOMR and Permitting Process: Spokane County requests that the CLOMR and CLOMR-F package include all floodplain modifications, both in the City and the County. Before County would sign off on the CLOMR application, we perform a detailed review and accept project plans sets, engineering/geotech reports addressing infiltration and floodplain hydraulic engineering, and a detailed Operation and Maintenance manual. Spokane County Public Works will not approve or issue floodplain permits for work in County until FEMA approves the CLOMR and CLOMR-F for the entire project and CSV has approved the development. It’s not clear if this is proposed, but there needs to be an alternative to infiltration testing beyond full scale construction of all the proposed drywells in the Triangle Pond. 3.Triangle Pond /Gustin Ditch– Need to address use of Spokane County’s existing drainage easement and current property owners needs for the Triangle Pond. This will require project proponent to negotiate an agreement to purchase or obtain easement and compensation for both. Also proposed plans cannot encumber County plans for extension of 40th Ave. around the Triangle pond. Note as well that these need to be addressed with letters of intent from property owners at a minimum before the County can sign off the Community Acknowledgement for the CLOMR application. 4. Risk Analysis- This table needs more detail on potential failure impacts. A map to address potential flooding would be helpful. This is critical for the Operations and Maintenance manual and future maintenance efforts to insure potential failures and their impacts are minimized. 5.Factors of Safety: Please clarify factor of safety for design flows in the stormwater systems, both on and off site. We see different flow capacity for pipes and system in different parts of the report and not sure its addressed at all for the off-site facilities. Suggest a table of facilities with design flows and factors of safety. August 31,2021 Chad W. Coles, P.E. – Director / County Engineer 1026 West Broadway Avenue  Spokane, WA 99260-0170 Phone: (509) 477-3600  Fax: (509) 477-7655  TDD: (509) 477-7133 www.spokanecounty.org 6. HOA Maintenance: Spokane County has continuing concern with HOA being responsible for maintenance, due to the uncertainty of their long term existence and capability to do the critical work needed with this complex of a stormwater/flood control facilities. Need stronger guarantee of ongoing maintenance for entire system, including facilities in Spokane County. Note also, a proposed detailed Operations and Maintenance Manual for the entire system and proposed implementation/organization plan will need to be submitted before the County will sign the Community Acknowledgment for the CLOMR. Thank you for the opportunity to comment. Sincerely, Marianne Barrentine, PE, CFM Water & Environmental Program Manager WCE No. 13-1166A September 24, 2021 City of Spokane Valley 501 N Anderson Ellensburg, WA 98926 Attn: Lori Barlow, Senior Planner Re: PRD-2015-0001 Painted Hills PRD – DEIS Agency Comments – Response Dear Lori This letter is intended to provide a response to comments received from the City of Spokane Valley, Spokane County and the Federal Emergency Management Agency (FEMA) during the public comment period for the Painted Hills Planned Residential Development (PRD) Draft Environmental Impact Statement (DEIS). This letter specifically addresses comments related to the FEMA review procedures and flood control measures planned for the PRD project and our comments are provided for additional information and context for the agency representatives planning to attend our upcoming meeting. Our hope is that by providing these responses prior to the meeting, we can offer agency representatives some more context and be as efficient as possible in resolving the questions and concerns at the meeting. For clarity agency comments are provided below with the development team response in bold. Item A – DEIS inclusion of Onsite and Offsite Improvements and Analysis  The first observation made while making the first read through of the material is that the DEIS does not seem to provide analysis for the entirety of the subject development or its potential effects outside of the project area. (Roxanne Pilkerton, FEMA) 1. Off-Site Proposal: We are concerned with the overall lack of detail and clarity on offsite proposal in Spokane County and with addressing of the associated impacts. Suggest maps/plans specifically to address the offsite areas. Also, the Biological Report and Cultural Resource Survey do not appear to address off site project area at all. (Marianne Barrentine, PE, Spokane County WA & Enviro Program Manager) The Gustin Pipe Plan Set under grading permit B160-4296, has been awaiting the completion of the EIS before acceptance by Spokane County for review. The detail of the offsite improvement is included within this plan set, the flood control analysis, and the CLOMR analysis. A biological assessment and a cultural resource survey has now been requested by Spokane County, So reports have been ordered at this time. The development team looks forward to the completion of this 2016 application, with the submittal of the Gustin Pipe plan set, and CLOMR. ~WCE Whipple Consulting Engineers, Inc. 21 South Pines Rd . • Spokane Valley, WA 99206 Li PO Box 1566 • Veradale, WA 99037 Phone 509-893-2617 • Fax 509-926-0227 • WhippleCE.com • lnfo@WhippleCE.com Civil , Structural, Traffic, Survey, Landscape Architecture and Entitlements City of Spokane Valley PRD-2015-0001 Painted Hills PRD – DEIS Agency Comments – Response October 12, 2021 Page 2 of 9 Item B1 – CLOMR and CLOMR-F – Anticipated Application  Are there parts of this proposed development that occur on land located in Unincorporated Spokane County? If so will a separate hearing and decision be made? Will both jurisdictions need to sign final plat/agreement/mapping documents? Will CLOMR/CLOMR-F applications need to be done by Spokane County? (Roxanne Pilkerton, FEMA) Yes, there are off-site flood control improvements planned within Spokane County. Specifically, under grading Permit B160-4296. These activities will also require a flood plain development permit. the county permit request is an administrative process and does not require a public hearing. These off-site improvements will be permitted separately from the PRD request in the City of Spokane Valley. However, Spokane County has placed the permit on hold pending the completion of the EIS. The development anticipates that as a condition of the PRD that these improvements would be completed. However, as this pipe proposal in Spokane County is on property within the UGA, and Zoned as LDR, there is the possibility that a following unassociated development project, under a separate land use application would take up the pipe project and move forward with the development of the property in accordance with Spokane County development code. The development Team has submitted a single CLOMR that includes both areas within the City of Spokane Valley and Spokane County as they are both linked to the compensatory storage over the Painted Hills Golf Course. Separate local agency application processes are required for the construction elements in each jurisdiction. However, each local agency application is intended to use the one CLOMR for reference. The CLOMR will include two Community Acknowledgement Forms, one for the City of Spokane Valley and one for Spokane County. • It appears that both a Conditional Letter of Map Revision (CLOMR) and a Conditional Letter of Map Revision based on fill (CLOMR-F) will be required for this proposed development. The DEIS only identifies a CLOMR as required and the SEPA Checklist lists a CLOMR-F as required. Because the applicant is anticipating removal from the SFHA by both off and on- site storm drainage and channel improvements, as well as fill being added to the site, both a CLOMR and CLOMR-F will be required. (Roxanne Pilkerton, FEMA) The terms CLOMR and CLOMR-F have been used interchangeably with this project. It is recognized that these are two different processes. The intent is to submit only a CLOMR. The CLOMR will involve fill, infiltration facilities, channelization, new culverts, and other components which change the floodplain hydraulics and floodplain extents significantly. Although there is fill involved as one component of the project, a CLOMR-F is specific to the MT-1 application process which is meant for more simplistic changes to the floodplain that do not require full hydraulics analysis and a more detailed review by FEMA. The complexity and interconnected components of the proposed project, as well as the proposed revisions to the floodways, require use of the MT-2 application process; therefore, the fill component will not be submitted separately as a CLOMR-F using the MT-1 process. Once City of Spokane Valley PRD-2015-0001 Painted Hills PRD – DEIS Agency Comments – Response October 12, 2021 Page 3 of 9 all project components are in place (with the exception of actual buildings), a LOMR will be submitted to reflect the changes. 2. CLOMR and Permitting Process: Spokane County requests that the CLOMR and CLOMR-F package include all floodplain modifications, both in the City and the County. Before County would sign off on the CLOMR application, we perform a detailed review and accept project plans sets, engineering/geotech reports addressing infiltration and floodplain hydraulic engineering, and a detailed Operation and Maintenance manual. Spokane County Public Works will not approve, or issue floodplain permits for work in County until FEMA approves the CLOMR and CLOMR-F for the entire project and CSV has approved the development. It’s not clear if this is proposed, but there needs to be an alternative to infiltration testing beyond full scale construction of all the proposed drywells in the Triangle Pond. (Marianne Barrentine, PE, Spokane County WA & Enviro Program Manager) An early draft of the CLOMR was submitted to the County under Grading permit application B160-4296. This permit has been put on hold pending the completion of the City of Spokane Valley EIS. Updated plans and reports have been prepared since the initial submittal as well as an offsite full scale drywell test. With the completion of the EIS, the CLOMR can be updated and submitted for City and County review. Item B2 CLOMR/CLOMR-F – approval process and order of permitting.  A CLOMR-F will necessitate Spokane Valley (and Spokane County if fill is being added to the site in Unincorporated Spokane County) to sign the community acknowledgment form. I’ve attached a RISK Map Fact Sheet to this email that gives an overview of what a community will be attesting to with their signature on a CLOMR/CLOMR-F. (Roxanne Pilkerton, FEMA) As stated above, the intent is to submit only a single CLOMR which contains all project components located within the City and the County, as the project components require use of the MT-2 application process. The CLOMR package will include Community Acknowledgement Forms for both the City and County.  FEMA strongly suggests that Spokane Valley (and Spokane County as required) have the applicant submit the CLOMR/CLOMR-F and receive FEMA approval prior to issuing the needed permitting for the installation of dry wells and infiltration testing. FEMA has recently reviewed the Spokane Valley ordinance as part of a Community Assistance Contact and supports and approves the proposed new language that states “If a CLOMR application is made, then the project proponent shall also supply the full CLOMR documentation package to the Floodplain Administrator to be attached to the floodplain development permit, including all required property owner notifications.”The DEIS states on electronic page 24 of 179, in the fourth paragraph that “Because it is expected that the CLOMR review and the City construction document review will be occurring at the same time, the applicant expects that any system design revisions requested/required by FEMA to ensure approval of the CLOMR will be integrated with revisions to the construction document package as necessary before the City issues final approval of the construction document.” It appears as if there is City of Spokane Valley PRD-2015-0001 Painted Hills PRD – DEIS Agency Comments – Response October 12, 2021 Page 4 of 9 already the assumption that system design changes could be required that further demonstrates why Spokane Valley (and Spokane County as required) have the applicant submit the CLOMR and CLOMR-F, receive approval, prior to issuing permits. FEMA suggests that if Spokane Valley (and Spokane County as required) considers approving the project that they would also consider adding a condition to the approval of the Painted Hills Development that no permits will be issued until the CLOMR/CLOMR-F are submitted to and given approval from FEMA. (Roxanne Pilkerton, FEMA)  FEMA can only approve a LOMR and LOMR-F if they are consistent with the approved CLOMR and CLOMR-F. Could Field changes in lieu of plans or process, not be allowed and all proposed changes are reviewed in consideration of the approved CLOMR and CLOMR-F documents? (Roxanne Pilkerton, FEMA) We understand that FEMA would like the CLOMR submitted as soon as possible. We also understand that the LOMR needs to reflect the construction elements submitted and approved within the CLOMR. In prior discussions and documents with the City, the applicant team has been told that the needed drywell installation and testing could not be permitted until the completion of the EIS. To understand the need for the drywell test is to understand the condition that the requirement was made. Below is a part of Sheet C1.3 (4-20-18 flood control plan set) with the location of the IPEC drywell emphasized. The test was not within the proposed pond location per stormwater standards (SRSM). So, the request (permit application) was made to test within the pond bottom. This test was denied, COSV letter Dated October 7, 2019, stating that the test could not be completed until after the EIS was complete. During the EIS process alternatives were developed with the preferred alternative being labeled Alternative #2. and additional model information, from WEST consultants was provided that calculated the flood flows and the volume of the floodwater anticipated to enter the pond in the 100 year event. This information expanded the size of the pond. IPEC Drywell Test SETlll G POND ROADSIDE SWALE 18" CULVERT City of Spokane Valley PRD-2015-0001 Painted Hills PRD – DEIS Agency Comments – Response October 12, 2021 Page 5 of 9 Without the required testing, alternative 2 was separated into 2A and 2B, during the redesign. Shown below is a portion of Sheet C1.3 (6-30-20 flood control plan set) As shown within the plan set the IPEC drywell test site is within the preferred option and within the smaller pond. This plan set submitted in June of 2020 has yet to be reviewed by City Staff (176 days and counting). With the determination of the design infiltration within the pond bottom per stormwater standards (SRSM), the flood control plans can be completed and the CLOMR updated. The plans, reports and CLOMR must first be reviewed by both Spokane County and the City of Spokane Valley, prior to their signing of the Mt-2 Form and allowing for the submittal of the CLOMR to FEMA The applicant anticipates that as a condition of the PRD approval, that the approval of the flood control plans would only occur after FEMA has reviewed and approved the CLOMR. In our upcoming meeting, the applicant team would like to discuss with the agencies if there are any other approaches to the permit sequencing that would better meet the agency and applicant needs.  On electronic page 15 of 279, partial paragraph, states that “Off-site and on-site storm drainage and channel improvements will be made that will result in the removal of approximately 48 acres of the site from the FEMA one percent-annual-chance floodplain (100-year floodplain).” The first full paragraph, details that “These improvements to the Gustin Ditch and to the triangle pond will eliminate the possibility of the floodwater inflows to the site from the east as modeled in the current FEMA floodplain insurance study for the area.” The second full paragraph asserts that “….will be completed that would also result in the removal of approximately 44 acres of off-site properties from the FEMA 100-year floodplain. Before these statements are made, the CLOMR/CLOMR-F would need to be reviewed and approved by FEMA. (Roxanne Pilkerton, FEMA) The DEIS is an intent document and until the development team is allowed to submit the CLOMR to FEMA, we can only report the findings of WEST Consultants. It is understood that this outcome (removal of mapped 100-year floodplain areas) is subject to review and IPEC Drywell Test PR CU RE T OPTION (BUD NGER RESUL ) 2-48" ADS -• 2 YPE HD E P PE CULVER-s/OUILETS S TTL NG POND EADWA L City of Spokane Valley PRD-2015-0001 Painted Hills PRD – DEIS Agency Comments – Response October 12, 2021 Page 6 of 9 approval by FEMA through the CLOMR. We can clarify this point in the Final EIS. (see response to Item B2)  Spokane Valley (and Spokane County as required) will need to ensure that flood permits are issued for any work on City roads located in the SFHA. Any fill or changes to culverts, bridge abutments, etc. will need to be included in the CLOMR and CLOMR-F applications. (Roxanne Pilkerton, FEMA) The development team understands that these features will be a component of the CLOMR application and subject to acquiring the appropriate permits.  FEMA recognizes that the subject property is located in the compensatory storage area designation of Spokane Valley. Because the DEIS speaks to the CLOMR removing this flood designation, FEMA suggests that the application for the CLOMR and CLOMR-F be approved by FEMA prior to permits being issued. (Roxanne Pilkerton, FEMA) As stated above, before the CLOMR can be submitted, City Staff needs to review the June 2020 submittal, which can then be used to finalizing the CLOMR for FEMA submittal. It is anticipated that the permits for the Flood Control Plans will not be issued until the public hearing of the PRD and conditioned for CLOMR approval by FEMA.  FEMA suggests that both Spokane Valley and the applicant, separately, request to speak to the MT-2 processing team to discuss the anticipated staging of fill that will be brought and stored on the site, if located in the SFHA. The storage of fill for 4 to 10 years could change flooding conditions and the CLOMR-F, and the CLOMR may need to address this. The MT-2 team is happy to discuss the requirements for the CLOMR and CLOMR- F applications for this situation. If contact information is needed, please let me know. (Roxanne Pilkerton, FEMA) The development now proposes that as a part of the installation of the flood control plans and grading permit(s) that the onsite and offsite flood control systems, and the onsite fill be placed prior to the final platting of the first phase of the PRD development. This is a change to the phased development timeline included in resource documents of the DEIS. The development is confident that the conditions of the LOMR can be meet as a majority of the fill material needed will come from onsite. The references to the 4-to-10-year phasing were a part of an early estimation of material prior to the expansion of the flood control infiltration pond, and was a means to quantify the anticipated truck traffic. This memo has been replaced by the haul plan and the conditions of transport of material included there in.  The SEPA checklist states that approximately 25 percent of the site would be covered with impervious surfaces, the DEIS states 25 percent in Alternative 2b, but 30 percent in Alternative 2a. (Roxanne Pilkerton, FEMA) City of Spokane Valley PRD-2015-0001 Painted Hills PRD – DEIS Agency Comments – Response October 12, 2021 Page 7 of 9 The SEPA Checklist written in 2018 for alternative 2 while valid has been expanded by the EIS process. The DEIS as an expansion of the original SEPA and circulated for public comment should be referenced instead.  The SEPA checklist states that “Off-site flood convenance improvements in Spokane County are anticipated on parcel numbers…..” FEMA would like to know how Spokane County is involved with the proposed project and where they are at with any required hearing or decision criteria. (Roxanne Pilkerton, FEMA) The development team has been directed that the offsite improvements under Grading Permit B160 -4296 are on hold until the EIS is complete. The offsite improvements include the extension/piping of the culvert under SR 27 and the pond improvements within the triangle parcel.  The SEPA checklist lists that the threatened or endangered species are “None known.” This seems to contradict information provided in Appendix H. (Roxanne Pilkerton, FEMA) The SEPA Checklist written in 2018 for alternative 2 before the completion of expert reports while valid has been expanded by the EIS process. The DEIS as an expansion of the original SEPA and circulated for public comment should be referenced instead. Therefore, the biological evaluation included in Appendix H is the information that should be referenced. .  The scope of the DEIS and the attached Appendices do not appear to be consistent in their analysis of the alternatives, or even which alternatives are discussed. (Roxanne Pilkerton, FEMA) The development team understands that there is some confusion in regard to the reference materials within the appendices as most of these documents were generated prior to the determination of significance by the City of Spokane Valley and the requirement of the EIS. During the EIS process the City of Spokane Valley has provided a review of the 2018 Flood Control Plans and the CLOMR, which has modified the project away from the design included in the original reports. Attempts to include the multiple alternatives associated with the EIS process within these singular reports have proved challenging.  QUESTION: When is Spokane Valley anticipating requiring that the LOMR and LOMR-F be approved? Would it be prior to buildings being constructed? (Roxanne Pilkerton, FEMA) It is the development team’s understanding that the LOMR would be required by the City and County before any building permits are issued within the existing mapped 100-year floodplain. City of Spokane Valley PRD-2015-0001 Painted Hills PRD – DEIS Agency Comments – Response October 12, 2021 Page 8 of 9 3. Triangle Pond /Gustin Ditch– Need to address use of Spokane County’s existing drainage easement and current property owners needs for the Triangle Pond. This will require project proponent to negotiate an agreement to purchase or obtain easement and compensation for both. Also proposed plans cannot encumber County plans for extension of 40th Ave. around the Triangle pond. Note as well that these need to be addressed with letters of intent from property owners at a minimum before the County can sign off the Community Acknowledgement for the CLOMR application. (Marianne Barrentine, PE, Spokane County WA & Enviro Program Manager) The development team has negotiated with the property owner of the triangle parcel for the construction of the pond improvements. The pond improvements are allowed under the maintenance clause of the County Stormwater Easement (83 0859 vol 659 Page 1803) created during the county road project (CRP-1923). The development team has also negotiated with the Gustin property owner, to install a pipe from the SR 27 ROW to the pond within the triangle parcel. The agreement also includes the creation of a stormwater easement to Spokane County, as the road project simply redirected the stormwater onto the Gustin property, which the property owner maintained within a ditch. Upon Completion of the EIS the Applicant wishes to complete the review of the Grading Permit B160-4296, including the use of the stormwater easement to disperse floodwater. 4. Risk Analysis- This table needs more detail on potential failure impacts. A map to address potential flooding would be helpful. This is critical for the Operations and Maintenance manual and future maintenance efforts to insure potential failures and their impacts are minimized. (Marianne Barrentine, PE, Spokane County WA & Enviro Program Manager) This table and map of the area was included to address comments from City of Spokane Valley in preliminary reviews of the DEIS. It is important to note that while there is always potential for failure, the probability of failure is even smaller than the occurrence of the 100-year flood event for which the system is designed. 5. Factors of Safety: Please clarify factor of safety for design flows in the stormwater systems, both on and off site. We see different flow capacity for pipes and system in different parts of the report and not sure its addressed at all for the off-site facilities. Suggest a table of facilities with design flows and factors of safety. (Marianne Barrentine, PE, Spokane County WA & Enviro Program Manager) The “Factor of Safety” quoted within the DEIS is in reference to the capacity of the two 48” pipes along Madison Road. There are other elements of the flood control system each with their own capacities for carrying floodwater. These capacities are greater than the capacity of the two 48” pipes. As the two 48” pipes serve as the limitation for the system, it was emphasized that their carrying capacity of the two pipes is 1.5 times the design flow event. City of Spokane Valley PRD-2015-0001 Painted Hills PRD – DEIS Agency Comments – Response October 12, 2021 Page 9 of 9 There is a report for the offsite Gustin Pipe, that includes a hydraulic analysis of the 36” pipe with the 16 CFS of flow from the 36” culvert under SR 27. This report is waiting to be submitted to Spokane County upon the completion of the DEIS. 6. HOA Maintenance: Spokane County has continuing concern with HOA being responsible for maintenance, due to the uncertainty of their long term existence and capability to do the critical work needed with this complex of a stormwater/flood control facilities. Need stronger guarantee of ongoing maintenance for entire system, including facilities in Spokane County. Note also, a proposed detailed Operations and Maintenance Manual for the entire system and proposed implementation/organization plan will need to be submitted before the County will sign the Community Acknowledgment for the CLOMR. (Marianne Barrentine, PE, Spokane County WA & Enviro Program Manager) The development team has considered the use of a HOA for the maintenance of flood control systems as has been done within the past under both jurisdictions. We believe that in this case the difference is the scale of the anticipated flow, and the compensatory storage of the site. While an HOA has as much or more motivation to complete the maintenance of a flood system as a public utility it seems that the voluntary nature of an HOA is more of the concern. An HOA is a non-technical management corporation that hires out the maintenance of HOA properties to professional services, including the maintenance of the flood control facilities. Since the publication of the EIS alternative to the traditional HOA has presented itself. Within the PRD is a commercial multi-family apartment development. While apartments are residential, they function as a commercial entity that routinely contracts with professional services, to maintain and insure continuity of the investment which at this time the 304 units of apartments proposed is approximately a $67.5 million dollar investment. Naturally the multi-family apartment development would be a part of the HOA. But if the parcels that include the flood facilities were owned by the multi-family apartment development, then their maintenance is ensured, and adds stability, consistency, and responsibility. The development team anticipates further discussions with the City of Spokane Valley in regard to this matter. If you have any questions or Comments in regard to this letter, please feel free to contact us at (509) 893-2617. Thank you Todd R. Whipple, P.E. TRW/bng Cc: File, Sponsor From:Pilkenton, Roxanne To:Lori Barlow Cc:Deanna Horton Subject:Painted Hills - Additional Comments Date:Wednesday, September 8, 2021 6:10:08 PM Attachments:image003.png[EXTERNAL] This email originated outside the City of Spokane Valley. Always use caution when openingattachments or clicking links. Hi Lori, Thank you so much for allowing me the time to speak during the DEIS Hearing for Painted Hills. While I was able to make comments I exceeded my three minutes and wanted to send my comments via email as well. Please accept the following comments: I thought I heard Mr. Stapleton say that if the offsite improvements were made to the east of the project, then flooding would not occur on site. Even if risk is reduced greatly, there is still risk. In Mr. Stapleton’s presentation he presented a “proposed floodplain” slide and then a “floodplain comparison” slide. The applicant has not submitted the required CLOMR and CLOMR-F to FEMA for review. Even after submitting the CLOMR and CLOMR-F, FEMA may ask for additional information, such as incorporating the entire project area in the limits of study. It appears as if the Chester Creek channel and levee are not included in the project analysis. The proposed floodplain may look vastly different than what was presented. The staging of large amounts of fill over a multi-year period should be discussed and analyzed in the CLOMR-F application. Mr. Stapleton spoke to the existing undersized culverts adjacent to the project. Does the City keep an inventory of culverts? Are these the only undersized culverts that affect the proposed project? HOA responsibilities as explained by Mr. Stapleton and as included in the DEIS are of concern and do not speak to what would happen if the HOA is to dissolve or go bankrupt. Please let me know if I can offer any further explanation. Kind regards, Roxanne Roxanne Reale-Pilkenton, CFM Floodplain Management Specialist | Mitigation | Region 10 Office: (425) 487-4654 | Mobile: (425) 892-4036 roxanne.reale-pilkenton@fema.dhs.gov | Preferred pronouns she/her Federal Emergency Management Agency fema.gov Federal Emergency Management Agency (FEMA), Region 10 is committed to providing access, equal opportunity, and reasonable accommodation in its services, programs, activities, education, and employment for individuals with disabilities. To request a disability accommodation contact me at least five (5) working days in advance at 425-487-4654 or roxanne.reale-pilkenton@fema.dhs.gov.