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SF-05-01 MISC DOCUMENTS S 06koaone ,,;oOValley 11707 E. Sprague Ave., Suite 106 ♦ Spokane Valley WA 99206 509.688.0239 ♦ Fax: 509.688.0295 ♦ hr@spokanevalley.org Memorandum Date: June 23, 2009 To: File ~ ~V-) From: Carrie A1ssAta, Deputy City Clerk Re: Moldy documents: Mica View C of E; Street and Drainage Plans Due to a water pipe breaking in City Hall's basement sometime last year, we are now discovering that several files contain documents with mold on them. The State Archivist Office confirmed with our City Clerk that we should make copies of, then destroy all moldy documents and make a not in the file; that is the purpose of this memorandum. The documents within this file are merely copies of documents which had mold and are now clean and can be handled without concern of contamination. In addition, the documents were moved from a 6-tab file to a 4-tab file, so some have been combined. The following lists the documents which were copied, then destroyed: • Submittal No. 4 for Review for Mica View - Certificates of Exemption Pierce Lane Private Road and Storm Drainage Plan, from WCE, dated September 15, 2005 • Preliminary Street and Drainage Plans Mica View C. of E., dated 9/16/04, Sheets 1, 2, 3, 41 51 61 71 8A, 813, 9, 10, 11, 12, 13, 14 of 14 YQ ze A AWCE, I . tembr 15, 2005 Sep W.O. No. 04-19 D~~ R ~ ~ Spokane County SEP 1 s ZD ~ Department of Public Works - Transportation D 05 1026 W. Broadway Spokane, WA 99260 V/Yo g~ . Attn: Tim Schwab, P.E. and Matt Zarecor, P.E. Development Services Engineers .cs~~CMLmmLIC DOCU11ffif` ; ~~°S ,y Re: Mica View - Certifcates of Exemption gPa~= ~1~11z Pierce Lane Private Road and Storm Drainage Plan ✓=-:s~ 0~~~~~`~'~`~ Submittal No. 4 for Review PROJECT f SUMINTA9. 0 ~ Dear Tim and Matt, Enclosed are one set of private road and drainage plans for review and approval. Also enclosed with this submittal are a revised Drainage Report and supplemental or revised calculations, of which a full document will be provided with mylars at final submittal. Below are responses to comments received from Spokane County in Tim's transmittal . of August 31, 2005 as well as responses to the City of Spokane Valley's comments from Sandra Raskell's, September 6, 2005 letter. Response to Spokane County Comments on 3rd Submittal County comments are bold and paraphrased with responses in normal text. PLANS 1. Side slope detail needs to be changed as the 5:1 slope cannot be maintained with the pond designs shown The detail for this has been revised to indicate that side slope will vary between 3:1 and 5:1 between the pond bottom and edge of road. 2. Provide trash rack for pipes larger than 18-inches This has been added . . . WHIPPLE CONSULTING ENGINEERS • CIVILAND TRANSPORTATION ENGINEERING 13218 E SPRAGUE AVENUE • SPOKANE VALLEY, WASHINGTON 99216 • PH: 509-893-2617 FAX: 509-926-0227 . '.3pokane County - Engineers . Submittal September 15, 2005 Page 2 3. Plans show inadequate treatment for Ponds J and K. We have reviewed this and believe the bottom area to be correct, the required pond bottom square feet for J and K from the GSM spreadsheet is 375 sf and the provided area from sheet 8A of 14 is 398 sf. This also includes the area of the cul-de-sac, however to better treat the water an additional 208 type swale was added to the end of the cul-de-sac to satisfy another comment, this pond is Pond L and has 600 sf of pond bottom area. ,4. Show the cut-off ditch in the typical section This has been added ~ ~s J 5. We recommend that you record a blanket drainage easement for the : natural drainage areas. This will be provided 6. Incorrect centerline elevation between 61+25 and 62+50 This has been checked and revised C . 7. The acceptance blocks should not show no preliminary plans These have been moved to "def points" and will only be printed on the mylars DRAINAGE REPORT 8. Add the pre and post 2 and 10 year storm information to the table in the report. t This has been added and the appropriate sheet attached for reference. ° 9. CN value comment Comment noted 10. Storrn water treatment for the cul-de-sac which is north and west of ° ponds J and K? A 208 pond has been added to the end of the cul-de-sac, calculations are attached for review - Spokane County - Engineers . 2"a Submittal September 15, 2005 Page 3 11. In the final drainage report malce sure all items are included or delete from the appendix list. Comment noted 12. Review and revise pond sizes between drainage report and plans Revised pond volume sheets have been provided and tables added in the revised Drainage Report 13. Comment on City of the Valley comments for that portion in the City of Spokane Valley. ~ Comment noted. - ~ MISCELLANEOUS 14. Question on work around the 70-foot easement at entrance from Pierce Road ~ This was discussed in a meeting and additional detail was added to the plans to more clearly define work effort and limits of such. 15. The drainage facilities lay outside the 70-foot private road easement, new easements shall be required. Please provide the following: a. Plat certificate, deed, deed of trust or conveying instrument b. List of signers c. Legal descriptions, exhibit of the easement area titled "Exhibit A", etc.. - d. Easement area drawing exhibit, titled "Exhibit B" e. Blanket Easement for the project drainage areas . We have requested these from the project surveyor and they will be provided under separate cover. 16. Provide a fire district approval letter This will be provided with final mylars 17. Provide a maintenance Manual and sinking fund calculations This will be provided with final mylars 18. Provide a draft copy of the CC&R's along with the HOA - UBI # ~ °Spokane County- Engineers - 2nd Submittal September 15, 2005 Page 4 This has been requested from the owner and wiil be provided upon receipt Citv of Spokane Valley Comments Below are comments from the City of Spokane Valley and their respective comments following each comment. , Plan Sheets ~ 1. Further detail the swale shown on Sheet 5 This has been added on Sheet 8B 2. Remove approval stamps . These have been turn off and will only be turned on for mylar use Drainage Report 1. Your report indicates a required volume for each swale to be 49 cf, but page 19 only lists 40 cf, please udate. This has been updated and the appropriate page included in this submittal. Essentially : the solution was to create a 40-foot by 1-foot flat swale (slope less than 2-percent) at the base of the hill to provide storage per the City of Spokane Valley technique of V=1133A, wherein, 40 cf of storage is required and 78 cf of storage is provided below the top back of curb along Pierce Road in the cul-de-sac, additional storage has also been provided in the cascading ponds throughout this reach by adding swales. Since the bottom swales alone store the required storage this additional storage has not been calculated and should help alleviate any potential problems associated with this reach. 2. Please submit drywell testing information A drywell was inadvertently added to this location which has since been removed 3. Report states galleries are to be used in svvales and ponds, however none shown. The report mis-spoke, under drains are used in the 208 ponds, not galleries . 'Spokane County - Engineers 2nd Submittal September 15, 2005 Page 5 4. It appears that there are numerous manholes/catch basins with less than the required 0.75 feet of freeboard. After a review of the plans we could not locate these freeboard issues. If it is in the pond volume sheet, it is only a reference elevation to determine elevations at the 0.8- foot mark from pond bottom for 208 ponds and is not specifically indicative of the design and construction contemplated. After your review should you have any questions related to this submittal please do not hesitate to call at 893-2617 or when your comments are ready for pick up so that this process can move along smoothly to approval/acceptance. SincereL 6 ~ ~ . ~ f . Todd R. Whipple, P.E. Enclosures - Plans and attachments as noted Cc: File DMINAGE REPORT FoR MiCAViEw CERTIFICATE OF EXEMPTION :-Spokane, Washington March, 2005 Revisec8 July, 2005 Revised August, 2005 Final Revision September, 2005 W.O. No. 2004-19 Prepared by: Whipple Consulting Engineers, Inc A Civil and Transportation Engineering Company 13218 E. Sprague Spokane Valley, WA 99216 Ph 509-893-2617 Fax 509-926-0227 This report has been prepared by the staff of WCE under the direction of the un rsigned professional engineer whose seal and signature appear hereon. _ °~wA , 2sas2 ~~s1~~~ EXPIRES 09-24-':Za(0' Todd R. Whipple, P.E. , - Final Response to Comments from 3rd Submittal and Final Submittai This is the 4th and final submittal of the Mica View C of E Drainage Report. The following are responses to comments received from Spokane County as well as the city of Spokane Valley (for that portion of Pierce Road in the City) which pertain to the storm drainage report. The cover letter detailing additional comments is a part of this resubmittal is attached for reference. Below are responses to comment received from Spokane County in Tim's transmittal of August 31, 2005 as well as responses to the City of Spokane Valley's comments from Sandra Raskell's, September 6, 2005 letter. Response to Spokane County Comments on 3rd Submittal County comments are bold and paraphrased with responses in normal text. PLANS 1. Side slope detail needs to be changed as the 5:1 slope cannot be maintained with the pond designs shown The detail for this has been revised to indicate that side slope will vary between 3:1 and 5:1 along the pond bottom and edge of road. 2. Provide trash rack for pipes larger than 18-inches This has been added 3. Plans show inadequate treatment for Ponds J and K. We have reviewed this and believe the bottom area to be correct, the required pond bottom square feet for J and K from the GSM spreadsheet is 375 sf and the provided area from sheet 8A of 14 is 398 sf. This also includes the area of the cul-de-sac, however to better treat the water an additional 208 type swale was added to the end of the cul-de-sac to satisfy another comment. 4. Show the cut-off ditch in the typical section TFiis has been added 5. We recommend that you record a blanket drainage easement for the natural drainage areas. This will be provided 6. Incorrect centerline elevation between 61+25 and 62+50 This has been checked and revised Whipple Constelting Engineers Page 2 of 26 Mica view C of E- Drainage Report a 7. The acceptance blocks should not show no preliminary plans These have been moved to "def points" and will only be printed on the mylars Drainaqe Report 8. Add the pre and post 2 and 50 year storm information to the table irr the report. This has been added and the appropriate sheet attached for reference. 9. CN value comment Comment noted 10. Storm water treatment north and west of ponds J and K A 208 pond has been added to the end of the cul-de-sac, calculations are attached for review 11. In the final drainage report make sure all items are included or delete from the appendix list. Comment noted 12. Review and revise pond sizes befinreen drainage report and plans Revised sheets have been provided and these will be inserted in the final drainage report 13. Comment on City of the Valley comments for that portion in the City of Spokane Valley. Comment noted. MISCELLANEOUS 14. Question on work around the 70 easement at entrance from Pierce Road This was discussed in a meeting and additional detail was added to the plans to more clearly define work effort and limits of such. 15. The drainage facilities lay outside the 70-foot private road easement, new easements shall be required. Please provide the following: - a. Plat certificate, deed, deed of trust or conveying instrumerrt b. List of signers c. Legal descriptions, exhibit of the easement area titled "Exhibit A", etc.. d. Easement area drawing exhibit, titled "Exhibit B" e. Blanket Easement for the project drainage areas Whipple Consulting Engineers Page 3 of 26 Mica Vietiv C of E- Drainage Report . We have requested these from the project surveyor and they will be provided under separate cover. This has been requested and will be transmitted under separate cover. The following comments are from the Citv of Sookane Valley, we have only responded to those comrnents that are generally not duplic.ate comments from Spokane County or were comments based on the original 208 presentation. 16. Provide a fire district approval letter This will be provided with final mylars 17. Provide a maintenance Manual and sinking fund calculations This will be provided with final mylars 18. Provide a draft copy of the CC&R's along with the HOA - UBI # This has been requested from the owner and will be provided upon receipt City of Spokane Vallev Comments Below are comments from the City of Spokane Valley and their respective comments following each comment. Plan Sheets 1. Further detait the swate shown on Sheet 5 This has been added on Sheet 8B 2. Remove approval stamps These have been tum off and wi11 only be turned on for mylar use Drainage Report 1. Your report indicates a required volume for each swafe to be 49 cf, but page 19 only lists 40 cf, please udate. This has been updated and the appropriate page included in this submittal. Essentially the - solution was to create a 40-foot by 1-foot flat swale (slope less than 2-percent) at the base of the hill to provide storage per the City of Spokane Valley technique of V=1133A, wherein, 40 cf of storage is required and 78 cf of storage is provided below the top back of curb along Pierce Road in the cul-de-sac, additional storage has also been provided in the cascading ponds throughout this reach by adding swales. Since the bottom swales alone store the required storage this additional storage has not been calculated and shou{d he{p alleviate any potential Whipple Consulting Engineers Page 4 of 26 Mica View C of E- Drainage Report problems associated with this reach. 2. Please submit drywell testing information A drywell was inadvertently added to this location which has since been removed 3. Report states galleries are to be used in swales and ponds, however none shown. The report mis-spoke, under drains are used in the 208 ponds, not galleries 4. It appears that there are numerous manholes/catch basins with less than the required 0.75 feet of freeboard. After a review of the plans we could not locate these freeboard issues. If it is in the pond volume sheet, it is only a reference elevation to determine elevations at the 0.8-foot mark from pond bottom for 208 ponds and is not specifically indicative of the design and construction contemplated. Response to Comments from 2"d Submittal This is the third submittal of the Mica View C of E Drainage Report. The following are responses to comments received from Spokane County as well as the city of Spokane Valley (for that portion of Pierce Road in the City) which pertain to the storm drainage report. The cover letter detailing additional comments is a part of this resubmittal is attached for reference. Below are responses to the comments from the Agencies, which were very similar and many of which were the same comments, which were resubmitted a second time Agency . comments are in bold and generally paraphrased and responses in normal type font as required. Major changes in the design and documentation as it relates to this submittal area as follows: • 208 Treatment for CARA and ASA were added to the ponds, which changed the overall design concept of the ponds by adding under drains for discharge. Generally, there is no discharge for the 2 year at all as it will be maintained within the ponds below the discharge pipe. • Discharge at the base of Pierce Road was revised to not flow freely from the edge of the road into the cul-de-sac. Instead a level ditch was added to control runoff. For this installation, 48 cf of volume was required and 78 cf of volume was provided below the top of curb into Pierce Road, as discussed with Sandra Raskell, City of Spokane Valley (COV). Response to Spokane County and COV Comments on 2nd Submittal County comments are bold and paraphrased with responses in normal text. Whipple Consulting Engineers Page 5 of 26 Mica View C of E- Drainage Report ~ PLANS 14. Provide larger and more easily read Bearings for the roactway centerline These have been added 15. Provide BCR, MCR and ECR station on the curb returns For this project the only curb returns that we now have are on the curb returns at both cul-de- sacs, and these have been added as well as stationing around the new/proposed cul-de-sac. 16. Provide a profile for the cul-de-sac. In speaking with Tim, we noted that Wendy had indicated that points with elevations were acceptable, which is why we presented what we did, also for the 2"d submittal we added a table to list slope between points, in checking with Tim, he indicated that the table would be fine. 17. Specify dryland grasses for the bioswales and ditches As with the previous submittal, the ditches are to be irrigated and mowed, we have tried to note this better 18. Sheet 6 has incorrect name in title block This has been revised 19. Update curve data table on sheet 2 This has been checked and revised 20. The radius of the cul-de-sac should be 50-feet This has been revised by enlarging the gravel shoulder to 5-feet from the proposed 2-feet, which takes the sac to 50-feet. 21. Show existing and/or proposed utilities for the project This project only proposes public water service which is shown on the plan, sewer will be on site septic. 22. Show proposed finish grade contours for the proposed road. These have been significantly revised and reviewed for adequacy and consistency 23. The edge of asphalt was not updated for deletion of the thickened edge, please revise. These have been lowered 0.30 feet Whipple Consulting Engineers Page 6 of 26 Mica Yietiv C of E- Drainage Report 24. The edge of asphalt was not revised from the deletion of the original cul-de- sac. This has been revised 25. Stopping construction stationing conflicts between 64+00 and 63+25 This has been revised to 64+00 26. Pierce LanelRoad connection detail, notes do not match or are missing This has been revised. 27. Add pipe profiles, show invert elevations, existing and proposed ground, other utilities, etc. These have been added 28. Minimum pipe size is 10-inch for u-uns less than 44', or use 12-inch. All pipe has been revised to 12-inch except for the control pipes from the proposed ponds which are 6-inch. 29. Storm drainage tees are not allowed, add structures or modify discharge point. Structures and/or discharge locations have been revised. 30. Pond bottom and side slope along with offset distance conflicts. The corresponding detail has been revised as there was conflicting information 31. Provide trash racks for all pipe over 18-inches These have been added 32. For locations with rip rap, indicated material gradation and thickness on plans. Add a filter blanket per Section 4 of the GSM Addendum These have been checked and calculations added 33. Provide a sump in the ponds and rotate the weir 90-degrees, also the 3-inch depth may be excessive. ° Based upon the plan revisions and 208 storage, this comment does not apply 34. In the typical ditch and pond section, distances and slope conflicts, etc. The corresponding detail has been revised as there was conflicting information. Whipple Consulting Engineers Page 7 of 26 Mica Yiew C of E- Drainage Report r 35. Construction outside the 70-foot road and utility easements, please provide copy of the easement to allow this construction to occur or revise plans. These have been requested from the project surveyor Pat Moore and will be provided when plan revisions have been accepted by the County. 36. The drainage facilities lay outside the 70-foot private road easement, new easements shall be required. Please provide the following: f. Plat certificate, deed, deed of trust or conveying instrument g. List of signers h. Legal descriptions, exhibit of the easement area titled "Exhibit A", etc.. i. Easement area drawing exhibit, titled "Exhibit B" We have requested these from the project surveyor and they will be provided under separate cover. DRAINAGE REPORT 37. The drainage report states that the project is outside the ASA, this is incorrect, per the GSM the project is in the ASA and treatment is required prior to discharge - Treatment has been provided by the following raising the discharge pipe 6-inches off the pond bottom and allowing for discharge through the pond bottom via under drain pipes to the outlet . structures. 38. A 10 year design storm must be evaluated as well as the 2 and 50 This has been added as required. 39. Pass through basins will still reach the road, either provide cut off swales or include in pond calculations Cut off swales have been added to the plans. 40. CN Value of 78, how was this determined. The value of 78 was an average of the 30-feet of developed roadside swale of CN=68 and the asphalt section CN=98 by using the following equation ((2x68)+98))/3 = 78. 41. Show/provide time of concentration calculations for the post-developed basins These have been included. Whipple Consulting Engineers Page 8 of 26 Mica Vietiv C of E- Drainage Report 21 42. Revise the plans and calculations to show that the 2-year pre-developed is not exceeded by the 2-year post development fiow rates. Discharge rates have not been revised due to the requirement for 208 type treatment and with the exception of very slow release rates through the pond bottoms to the infiltration pipes, little to no flow is expected from the 2-year storms. 43. Revise detention areas to match pond areas that can be built. We are confused by this comment, but in discussions with Tim, believe that this relates back to the 3:1 vs 5:1 and some dimensional problems with a detail and or section which has been revised. 44. Use rational formula to check ditch velocities These have been revised and re-calculated and remain within acceptable limits. 45. Show how storm water at the end of Pierce Lane at Pierce Road is treated and detained. Prior to submittal of this 2"d package, this issue was discussed with Sandra Raskell at the City of Spokane Valley and it was indicated that because of the existing easement and right of way conditions and some of the changes made by the adjacent land owners the last 100-feet of roadway could not be stored, however, it would be routed to the roadside ditches and discharged from the swales to Pierce Road with as much detention as could be provided. The design includes the design for this comment. 46. Provide rip rap calculations These have been provided. MISCELLANEOUS 34. Provide a fire district approval letter This will be provided upon acceptance of the drainage plans 35. Provide an O&M Manual and Sinking Fund calculations. These will be provided after initial review of this 3rd submitta) 36. Provide a draft copy of the CC&R's along with the HOA- UBI # This has been requested and will be transmitted under separate cover. The following comments are from the Citv of Spokane Vallev, we have only responded to those comments that are generally not duplicate comments from Spokane County or were comments based on the original 208 presentation. Whipple Corrsulting Engineers Page 9 of 26 Mica View C of E- Drainage Report 9.Verify how runoff downstream of 62+50 will be treated and disposed, prior to entering the City of Spokane Valiey. As shown on the basin map and plans, this project proposes to intercept all storm drainage at about station 62+50 via Ponds A1 and A2 which discharge to the east. Below or northerly of 62+50, and currently within the City of Spokane Valley, the adjacent homeowners have disturbed the soil and surrounding area of the private road easement to a point that drainage treatment and discharge are nearly impossible if not completely impossible to treat and dispose. We have spoken with Sandra Raskell at the City of Spokane Valley and have indicated that we can cut off all upstream water south of 62+50 so that only that water downstream of that point will continue to run within the City and that our ability to treat and dispose is nearly impossible. Therefore, we have requested relief that the that area between 62+50 and 63+50 be allowed to run free as the existing slopes do now with no other upstream contributing basins being allowed to run to the cul-de-sac. Essentially the solution was to create a 40-foot by 1-foot flat swale (slope less than 2-percent) at the base of the hill to provide storage per the City of Spokane Valley technique of V=1133A, wherein, 40 cf of storage is required and 78 cf of storage is provided below the top back of curb along Pierce Road in the cul-de-sac. 12. Specify a grassy cover for the roadside swale This has been added; the grassy swale will be irrigated and mowed. Response to Comments from Original Submit#al This is the second submittal of the Mica View C of E Drainage Report. The following are . responses to comments received from Spokane County as well as the City of Spokane Valley (for that portion of Pierce Road in the City) which pertain to the storm drainage report. The cover letter detailing additional comments is a part of this resubmittal is attached for reference. Below are responses to the comments from the Agencies, which were very similar in nature and therefore will be answered in a very generic format. Agency comments are in bold italics and generally paraphrased and responses in normal type font as required. It should be noted that the overall design methodology for this project has been revised to move to a detain and release concept as the C of E's and associated road construction are being developed at a 1 per 5 Acre density, with the exception of the roadway, little if any additional runoff will be generated by the total development. Therefore, this project has been substantially revised along two major categories; first, the runoff from the road way will be treated and detained in swales and ponds along the roadside ditch and discharged at pre-developed 2 year and 50 year rates; second, pass through pipes have been included to discharge pre-developed rates under the proposed road along existing and defined drainage ways. Plans - General Comments • Drywell discharge issues with depth in ponds, geotech information etc. Whipple Consulting Engineers Page 10 of 26 Mica View C of E- Drainage Report . The concept for this project has been significantly revised to be similar to a large lot project, made up of C of E parcels where no specific drainage conditions have been imposed. Based on this the concept for this project has been revised to a detain and release design, where all curbs have been removed so storm water can move directly from the roadway into the grass lined swale and be directed via the swale to the individual detention ponds. From there the storm water will be stored to varying depths, and released at pre-developed rates at either the 2 or 50 year discharge intervals. This is accomplished via pipes, and weirs. Therefore, please note that NO DRYWELLS ARE PROPOSED AT THIS TIME. • Pond with berms 4-feet or higher wild require key-way and special consfruction, per Figure 47 of fhe Standard Plans. This has been noted and added to the plans ~ Easements for ponds outside of the existing easements This has been forwarded to the surveyor and will be provided when ready for easement preparation. • Remove the public roadway portion of this project, both agencies have requested that the access to this project from the existing cul-de-sac at Pierce Road be make private. This revision has been made and the singular access to this project has been made a private road. The following are more specific responses to comments received from Spokane County. Drainaqe Report 16. Discrepancies between plans and drainage report Because of the significant drainage plan and report changes these have been checked and verified prior to submittal of this plan set. 17. Provide a pre-developed basin map This has been included within the plans set and used for the crossing/pass through pipe construction as an exhibit. 18. More clearly define sub basins This has been provided on a revised post-developed basin map. 19. Detention facilities not storing enough, issues with rines and drywell outflow rates. Whipple Consulting Engineers Page 11 of 26 Micu Yiew C of E- Drainage Report i ~ t The drainage scenario has been revised and the drywelis omitted as well as new pond calculations and designs have been incorporated. 20. Verify the calculations for 208 area being provided. We have revised the drainage calculations and moved to a swale catchment, with discharge to a detention pond and then release at the 2 and 50 year release rates and no 208 calculations are provided. 21. Provide further explanation of the calculation table in the drainage report, etc. This has been added, modified or changed where required Miscellaneous 22. Provide a fire district approval letter. Requested at the time of this submittal will be provided prior to final plan approval 23. Provide a mainfenance manual and sinking► fund calculations This will pre provided with the next submittal, be that paper or mylar as this proposed drainage solution has not been reviewed yet. , 24. Provide a draft copy of the CC&R's along with the Homeowners Association UBI This has been requested from the owner and will be provided prior to final plan approval. Whipple Consulting Engineers Page 12 of 26 Mica View C of E- Drainage Report REVISED DRAINAGE REPORT GENERAL The proposed Mica View Certificate of Exemption development consists of fourteen 5± acre residential lots located on approximately 87.95 acres. The site is located in the Dishman-Mica area west and south of Ponderosa Drive, approximately one-third of a mile northwest of the Dishman-Mica Road and Hallet Drive intersection in Spokane County. The intent of the storm drainage facilities for this project is to capture treat and discharge the runoff from Pierce Lane, a 3,300 If PRIVATE Road. The site lies within portions of sections 4 and 5 of T 24 N., R 44 E., W.M., and this project is not within the aquifer sensitive area, therefore treatment is required. A vicinity map is attached. PURPOSE The purpose of this drainage report is to determine the storm drainage facilities that will be required to treat and dispose storm water runoff for the new roadway provided for this project. The facilities, as proposed, will be designed to treat and dispose of the 2, 10, 50 and 100 year storms through a combination of swales, detention ponds and outlet structures which will be used to convey, store treat and dispose of the storm water runoff from this project. ANALYSIS METHODOLOGY The Rational Method with the Intensity, Duration and Frequency (IDF) curves from the Spokane, Medical Lake, Reardon, Cheney and Rockford intensity curve were used in the runoff and bowstring calculations for the peak flows for this project where required. Generally, most of the design has been completed using Hydraflow Hydrographs, version 8.0.0.1 by Intelisolve which have been used to implement the HEC-22, TR-20 and TR-55 drainage calculations and methods. TOPOGRAPHY The site has a rolling terrain with existing slopes varying from approximately 1% to over 18%. The future terrain of the project will match existing slopes as much as possible. The PRIVATE roadway will have a maximum slope of 10-percent. SOILS As can be seen from the accompanying soils map from the Spokane County Soils Survey as performed by the USDA, Soil Conservation Service (SCS), the site consists of three types of soils all generally within the Class B and Class C soil types. They are Clayton sandy loam (Cu6), Spokane complex (SsC), and Spokane very rocky complex (StC). The soil descriptions are as follows. Whipple Consulting Engineers Page 13 of 26 Mica view C of E- Drainage Report I i CuB - Clayton sandy loam, 0- 8 percent slopes: Within this complex the clayton soils are very deep, well-drained, moderately coarse textured soils formed from glaciofluvial material on broad, nearly level gently sloping terraces, with loam forrning the top 20 to 40 inches of surface layer. Hydrologic Soil Classirication - B SsC - Spokane complex, moderately shallow, 0 to 30-percent slopes: The Spokane complex series of soils are generally well drained and moderately coarse textured. These soils are similar to Spokane loam soils except that the depth of soil to bedrock varies from 20 to 30-inches with this soil type. These soils have a slight susceptibility to frost action, moderate to rapid permeability, and moderate resistance to erosion. Hydrologic Soil Classification - C StC - Spokane very rocky complex, moderately shallow, 0 to 30-percent slopes: The Spokane very rocky complex series of soils are generally well drained and moderately coarse textured. These soils are similar to Spokane loam soils except that the depth of soil to bedrock varies from 20 to 30-inches with this soil type and rock outcrop is included in these complexes. These soils have a slight susceptibility to frost action, moderate to rapid permeability, and moderate resistance to erosion. Hydrologic Soil Classification - C DRAINAGE NARRATI!!E BASIN SUMMARY Pre-Developed - Offsite Pass Through Basins Based upon comments received, an overall aerial topography map at 2-foot contours was ordered from Spokane County and supplied by John Bottelli, GIS manager. This additional documentation indicated that this site was subject to up gradient offsite pass through storm drainage. Therefore, attached to this report and included within the plan set, sheet 11 of 14 shows the 5-offsite basins that flow through this site. Theses upstream basins will generally be unaffected by the development of this property. Based upon comments received cut-off ditches/trenches have been added to keep the upstream offsite water and developed storm events separate. As to a pre developed basin map, the site generally lays along the ridge line of the hill with the exception of the pass through basins, storm drainage as it currently does will head to the north or south down hill along existing drainage ways. Pass Throuqh Basins As noted above, the aerial contours received from Spokane County have indicated that Whipple Consulting Engineers Page 14 of 26 Mica View C of E- Drainage Report r five basins A, B, C, D and E as shown on sheet 11 of 14 are generally up gradient . basins and may require cut-off ditches and pass through pipes to continue the flow of water from up gradient to down gradient. A brief description of each basin follows. Pass throuqh Basin A This basin is the westerfy pass through basin with the following characteristics • Area = 8.16 Acres • CN Value = 66 • Tc Length = 1100 If • 100-Year Discharge = 5.49 cfs • Solution for Pass Through = 24-inch Culvert with varying slopes • Velocity = 4.46 fps • 24-inch Capacity = 17.33 cfs @ 2%+/- Pass throuqh Basin B This basin is the second basin from the west with the following characteristics e Area = 6.68 Acres 0 CN Value = 66 o Tc Length = 1400 If • 100-Year Discharge = 2.89 cfs • Solution for Pass Through = 24-inch Culvert with varying slopes • Velocity = 3.63 fps • 24-inch Capacity = 17.33 cfs @ 2%+/- Pass throuQh Basin C This basin is the middle of the five upgradient basins with the following characteristics • Area = 5.77 Acres • CN Value = 66 • Tc Length = 1000 If • 100-Year Discharge = 2.70 cfs • Solution for Pass Through = 24-inch Culvert with varying slopes • Velocity = 3.55 fps • 24-inch Capacity = 17.33 cfs @ 2%+/- Whipple Consulting Engineers Page 15 of 26 Mica Yiew C of E- Drainage Report Pass throuqh Basin D This basin is the second basin from the east with the following characteristics • Area = 3.21 Acres • CN Value = 66 • Tc Length = 750 If • 100-Year Discharge = 1.50 cfs • Solution for Pass Through = 24-inch Culvert with varying slopes • Velocity = 1.50 fps • 24-inch Capacity = 17.33 cfs @ 2%+/- Upstream/Uqaradient Basin E This basin is the last basin to the east and it should be noted that while this is an upstream/upgradient basin, it generally does not reach the roadway and rather makes a characteristic semi-circular tum back to the main channel which lies south of the project area. This basin was modeled because a site visit will reveal that it appears upgradient but the contours do not lend themselves to this issue. Therefore, this information is provided for consideration, with the following basin characteristics, • Area = 4.87 Acres o CN Value = 66 • Tc Length = 900 If • Discharge = 2.11 cfs • Solution for Pass Through = does not pass under the road, ditch continues east • Velocity = 2.11 fps • 24-inch Capacity = 24.42 cfs @ natural contour Post-Developed - Basin Summaries Generally the site has been divided up into 13 basins with Basin A encompassing both sides of the road into A1 and A2, with a shared discharge. Additionally, comments received from the City of the Valley regarding Pierce Lane have resulted in the creation of two new basins for the 3rd submittal. These basins are A1 A and A2A which encompase that area north of Basins A1 and A2 as well as ponds A1 and A2, which cut off all water at 62+50. As noted eariier, this project is in the aquifer sensitive area and also within the "high" susceptibility area of the CARA map thereby requiring treatment of storrnwater prior to discharge. As this area has soils that are not conducive to drywells, see geotech reports attached in the appendix. The previous drainage report and geotechnical information make groundwater discharge very difficult due to somewhat poor soils and the presence of shallow rock. Therefore, and as noted earlier, it was Whipple Consulting Engineers Page 16 of 26 Mica Yiew C of E- Drainage Report determined to revise this drainage report and revise the site design from drywell discharge and 208-type swale/ponds to detention ponds using the natural drainage inrays as discharge locations. Once captured, stormwater will be treated by the pond bottoms with assistance from under drain pipes place 1 to 2 feet below the pond bottom to insure that these ponds, as required will drain within the required 72 hours. Therefore, this analysis considers the following. • That building 14 houses on 88 acres will have little to no impact to existing runoff characteristics or require enough change between the pre and post developed CN values to warrant specific analysis. . • That the single largest contributor to a change in runoff pattems, volumes and rates will be the presence of the 30-foot wide PRIVATE asphalt roadway. • Therefore, the limits of the basins are to the extents of the proposed improvements along the roadway including the proposed swales and ponds, this would require detention for the development of the 60-foot wide roadway and swale prism throughout the length of the roadway. • Because of this revision in drainage philosophy and in trying to determine better and more reasonable ways to control runoff from the streets, the Type "C" curbs that were originally proposed have been omitted so that straight sheet flow from the roadway along its entire length will run into the swales which will direct all runoff to the proposed ponds, where the storm water will be treated in the 6-inch sump that has been introduced into 'each pond with this 3rd submittal. The stormwater within this 6-inch sump will then be discharged via either evaporation, evapotranspiration or infiltration through the pond bottoms. • Based upon these basic concepts the basins were divided by existing drainages or drainage ways within the overall property so that discharges will follow historical drainage paths with maximum discharge from each pond limited to the pre-developed 50-year storm event, and in all cases below the pre-developed discharge rate. Basins A1 A and A2A This basin represents that portion of Pierce Lane from the City Limits to the existing Pierce Road cul-de-sac. As noted in the description for Basins A1 and A2 treatment options for this basin are difficult because Pierce Lane is on a 50-foot easement where room for ponds are none existent. Additionally, the adjacent neighbors have changed the land form so that overland discharge to historical drainage ways is not applicable. This is all compounded by the presence or rock and shallow silty/clayey soils that are not conducive to groundwater discharge. Based upon eady discussion Whipple Consulting Engineers Page 17 of 26 Mica Vietiv C of E- Drainage Report a with the COV these constraints were discussed and originally, it was thought that discharge directly to Pierce Road for this 125 foot segment could be accommodated. However, in this last review this has been modified to require storage behind the curb of the runoff from this area. Therefore, runoff volume from this basin has been calculated using the COV method of V=1133A to determine the extent of ponds. Additionally, and as a precautionary measure, a gravel gallery has been installed under the pond bottom with dimensions of 2' x 3' with a grate 6-inches above the pond bottom to facilitate some discharge to the underlying soils. Ultimately discharges from these two swales are either through, evaporation, evapotranspiration or infiltration. Highlights for this basin are as follows: • Basin (imits - 62+50 to 63+75 (125 feet) • Area = 0.27 / 0.41 Acres • Pre Developed CN = 66 • Post Developed CN = 78 • Weighted "C" = 0.27 / 0.41 • 2 year Discharge Rate (rational) = 0.15 / 0.10 • 10 year Discharge Rate (rational) = 0.23/ 0.16 • 25 year Discharge Rate (rational) = 0.30 / 0.20 • 50 year Discharge Rate (rational) = 0.34 / 0.23 • 100 year Discharge Rate (rational) = 0.38 / 0.26 e In all instances, the higher rate was used for analysis • Total Storage Volume @ 1.0 feet = 78 cf Basin A (A1 and A2) This basin is located above the existing Pierce Road and utilizes an existing drainage - way to the east as its discharge point. Highlights for this basin are as follows: • Basin limits - 58+50 to 62+50 • For this basin the length of asphalt for design was assumed to be 500 If rather than 400 If to compensate for the inability to detain the discharged water from 62+50 to 63+50 (at existing Pierce Road) because of existing home construction and driveway irnprovements associated with the properties 'along the right of way that have modified the existing terrain to preclude use of any discharge to an existing drainage way. See photos in the appendix. • Area = 0.78 Acres • Pre Developed CN = 66 • Post Developed CN = 78 • Pre Developed Discharge Rate, 2 year = 0.00 cfs • Pre Developed Discharge Rate, 50 year = 0.17 cfs • Post Developed Discharge Rate, 2 year = 0.12 cfs • Post Developed Discharge Rate, 50 year = 0.94 cfs Whipple Consulting Engineers Page 18 of 26 Mica Vieiv C of E- Drainage Report • Total Storage Volume @ 0.5 feet = 395 cf 0 "208" Required Bottom Area = 710 sf 0 "208" Bottom Area Provided = 710 sf Basins B and C These basins are identical in nature each discharging to their respective sides of the roads to the existing drainage ways. Highlights for each individual basin are as follows, please keep in rnind that these are duplicate basins: • Basin limits - 53+00 to 58+50 • Area = 0.39 Acres • Pre Developed CN = 66 • Post Developed CN = 78 • Pre Developed Discharge Rate, 2 year = 0.00 cfs • Pre Developed Discharge Rate, 50 year = 0.10 cfs • Post Developed Discharge Rate, 2 year = 0.06 cfs ~ Post Developed Discharge Rate, 50 year = 0.26 cfs • Total Storage Volume @ 0.5 feet = 390 cf 0 "208" Required Bottom Area = 700 sf 0 "208" Bottom Area Provided = 700 sf Basins D and E These basins are identical in nature each discharging to their respective sides of the roads to the existing drainage ways. Highlights for each individual basin are as follows, please keep in mind that these are duplicate basins: • Basin limits - 46+00 to 53+00 • Area = 0.51 Acres • Pre Developed CN = 66 • Post Developed CN = 78 • Pre Developed Discharge Rate, 2 year = 0.00 cfs • Pre Developed Discharge Rate, 50 year = 0.09 cfs • Post Developed Discharge Rate, 2 year = 0.05 cfs • Post Developed Discharge Rate, 50 year = 0.43 cfs • Total Storage Volume @ 0.5 feet = 513 cf 0 "208" Required Bottom Area = 933 sf •"208" Bottom Area Provided = 933 sf Whipple Consulting Engineers Page 19 of 26 Mica Vievv C of E- Drainage Report f Basins F and G These basins are identical in nature each discharging to their respective sides of the roads to the existing drainage ways. Highlights for each individual basin are as follows, please keep in mind that these are duplicate basins: • Basin limits - 42+50 to 46+00 • Area = 0.25 Acres • Pre Developed CN = 66 • Post Developed CN = 78 • Pre Developed Discharge Rate, 2 year = 0.00 cfs • Pre Developed Discharge Rate, 50 year = 0.05 cfs • Post Developed Discharge Rate, 2 year = 0.02 cfs • Post Developed Discharge Rate, 50 year = 0.21 cfs • Total Storage Volurne @ 0.5 feet = 263 cf 0 "208" Required Bottom Area = 449 sf 0 "208" Bottom Area Provided = 462 sf Basins H and I These basins are identical in nature each discharging to their respective sides of the roads to the existing drainage ways. Highlights for each individual basin are as follows, please keep in mind that these are duplicate basins: • Basin limits - 34+00 to 42+50 • Area = 0.62 Acres • Pre Developed CN = 66 • Post Developed CN = 78 • Pre Developed Discharge Rate, 2 year = 0.00 cfs • Pre Developed Discharge Rate, 50 year = 0.10 cfs • Post Developed Discharge Rate, 2 year = 0.06 cfs • Post Developed Discharge Rate, 50 year = 0.52 cfs • Total Storage Volume @ 0.5 feet = 610 cf •"208" Required Bottom Area = 1117 sf •"208" Bottom Area Provided = 1126 sf Basins J and K These basins are identical in nature each discharging to their respective sides of the roads to the existing drainage ways. This basin includes the storage for the cul-de-sac which is below grade of the ponds and allows for the cul-de-sac runoff to be captured in the swales and discharged directly to the respective drainages. Highlights for each individual basin are as follows, please keep in mind that these are duplicate basins: Whipple Consulting Engineers Page 20 of 26 Mica Vieiv C of E- Drainage Report ~ 0 0 Basin limits - 29+50 to 34+04 • Area = 0.21 Acres • Pre Developed CN = 66 • Post Developed CN = 78 • Pre Developed Discharge Rate, 2 year = 0.00 cfs • Pre Developed Discharge Rate, 50 year = 0.06 cfs • Post Developed Discharge Rate, 2 year = 0.03 cfs • Post Developed Discharge Rate, 50 year = 0.25 cfs • Total Storage Volume @ 0.5 feet = 229 cf 0 "208" Required Bottom Area = 375 sf 0 "208" Bottom Area Provided = 398 sf Tabie 1 A- SCS Basin Summary Table - 50 - Year Data SP4KANE COUNTY BASIN INFORMATiON - - ` 50 YEAR QATA . . , - ~ ~ . : 50-YEAR 50-1(EAR ' MINIMUM . CN VALUES CN VALUES PRE POST .50-YEAR _ BASINS QREA (AC) :PRE , POST DEVELOPED DEVELOPED DETENTION . DEVELbPED DEVELOPED RUNOFF RUNOFF VOLUME RATE (CFS) RATEJCFS) ~CfL.= - A1 ~ 0.39 ~ 66 ~ 78 ~ 0.17 ~ 0.94 ~ 1083 A2 ~ 0.39 ~ 66 ~ 78 ~ 0.17 + 0.94 ~ 1083 B ~ 0.39 ~ 66 78 ~ 0.10 ~ 0.47 ( 483 C ~ 0.39 ~ 66 + 78 ~ 0.10 ! 0.47 ~ 483 D ~ 0.51 ~ 66 ~ 78 ~ 0.09 0.48 ~ 758 - E ~ 0.51 ~ 66 N 78 ~ 0.09 0.48 ~ 758 F ~ 0.25 ~ 66 ~ 78 ~ 0.05 ' 0.21 ~ 292 G ~ 0.25 ~ 66 ~ 78 ~ 0.05 ( 0.21 ~ 292 H ~ 0.62 ~ 66 ~ 78 ~ 0.10 ~ 0.52 ~ 830 ' I ~ 0.62 ~ 66 ~ 78 ~ 0.10 ~ 0.52 ~ 830 J ~ 0.21 ~ 66 ~ 78 J 0.06 ~ 0.25 ~ 232 K ~ 0.21 ~ 66 ~ 78 ~ 0.06 j 0.25 ~ 232 T-otal .s 4 . ~74- --66 78 - Whipple Consulting Engineers Page 21 of 26 Mica View C of E- Drainage Report Table 1 B- Supplemental SCS Basin Summary Tabie - 2- Year Data SPOKANE COUNTY BASIN SUPPLEMENTAL INFORMATION 2 YEAR DATA . . 2-YEAR 2.-1(EAR 2-YEAR 2-YEAR - DETENTION PRE POST POST VOLUME ST4RAGE BASINS. AREA (AC) DEVELOPED DEVELOPED DEVELOPED • TO 208 . RUNOFF RUNOFF DISCHARGE VOLUME DEPTH _ RATE CFS RATE (CFS) RATE (CFS) (CF) (CF) _ ; . A1 ~ 0.39 ~ 0.00 ~ 0.12 ~ 0.02* ~ 385 ~ 395 A2 ~ 0.39 ~ 0.00 ( 0.12 ~ 0.02* ~ 385 395 6 ~ 0.39 ~ 0.00 0.06 ~ 0.01 192 ~ 390 C ~ 0.39 ~ 0.00 0.06 ~ 0.01 ~ 192 ~ 390 D ~ 0.51 ~ 0.00 ~ 0.05 0.01281 ~ 513 E ~ 0.51 ~ 0.00 ~ 0.05 0.01 281 ~ 513 F ~ 0.25 ~ 0.00 ~ 0.02 ~ 0.00 ~ 123 ~ 263 G ~ 0.25 ~ 0.00 ~ 0.02 ~ 0.00 ~ 123 263 H ~ 0.62 ~ 0.00 ~ 0.06 ~ 0.01 306 ~ 610 I ~ 0.62 ~ 0.00 ~ 0.06 ~ 0.01 306 ~ 610 J ~ 0.21 ~ 0.00 ~ 0.03 ~ 0.00 ~ 104 ~ 229 K ~ 0.21 0.00 ~ 0.03 ~ 0.00 ~ 104 ~ 229 Totals~ 4.74 ~ ~ 7,356 calculated rate shown is not consistent with the requirement for storage for the 208 event and the pipe at 6-inches in depth, rate should be zero. Whipple Consulting Engineers Page 22 of 26 Mica Vieiv C of E- Drainage Report 1 Table 1 B- Supplemental SCS Basin Summary Table - 10 - Year Data SPOKANE COUNTY BASIN SUPPLEMENTAL INFORMATIO{V 10 - YEAR DATA 1 O YEAR ' 1 O-YEAR 1 O YEAR 1 O-YEAR MINiMUM PRE POST POST . 5 0 YEAR STORAGE BASINS AREA (AC) DEVELOPED DEVELOPED DEVELOPED DETENTION RUNOFF RUNOFF DISCHARGE VOLUME VOLUME . . . RATCFS~ RATE (CFS _ RATE (CFS) _ (CF) . . _(CF) _ - I - I - I I A1 ~ 0.39 0.04 ~ 0.54 ~ 0.17* ~ 937 ~ 1083 A2 ~ 0.39 0.04 ~ 0.54 ~ 0.17* ~ 937 ~ 1083 B ~ 0.39 ~ 0.02 ~ 0.27 ~ 0.04* ~ 419. ~ 483 C ~ 0.39 ~ 0.02 ~ 0.27 0.04* ~ 419 ~ 483 D ~ 0.51 0.02 ~ 0.27 0.02 ~ 657 ~ 758 E 0.51 ~ 0.02 ~ 0.27 ~ 0.02 ~ 657 ~ 758 F 0.25 ~ 0.01 ~ 0.12 ~ 0.01 ~ 252 ~ 292 G ~ 0.25 ~ 0.01 ~ 0.12 ~ 0.01 252 * ~ 292 H ~ 0.62 ~ 0.03 ~ 0.29 ~ 0.02 ~ 718 ~ 830 I 0.62 ~ 0.03 ~ 0.29 ~ 0.02 ~ 718 ~ 830 J 0.21 ~ 0.01 ~ 0.15 0.01 ~ 200 ~ 232 K ~ 0.21 ~ 0.01 ~ 0.15 ~ 0.01 ~ 200 ~ 232 _Totals l 4.74 7,356 * = rate shown is inconsistent with options for discharge, a 0.01' change in outlet elevation results in 0.00 cfs as discharge, therefore, we believe that the rate should be the same or equal to the pre-developed level. Table 1 D- City of Valley Basin Summary Table ` CITY OF THE VALLEY BASIN INFORMATION 10-YEAR 50 YEAR 100-YEAR STORAGE WEIGHTED - ' VOLUME @ BASINS AREA (AC) «C„ DEVELOPED DEVELOPED DEVELOPED V-1133A RATE (CFS). RATE (CFS) RATE (CFS) ~CF _ I - ` _ - I ~ I A1 A ~ 0.28 ~ 0..27 ~ 0.23 ~ 0.34 ~ 0.38 ~ 48.7 A2A ~ 0.12 ~ 0.41 ~ 0.16 ~ 0.23 ~ 0.26 48.7 Whipple Corrsulting Engineers Page 23 of 26 Mica View C of E- Drainage Report POND DESIGN Ponds and outflow structures for this project were generally designed and sized using the Hydraflow program noted earlier. In some instances pond configurations were rnodified to better accommodate the existing site topography, but required volumes and outflow structures were maintained to meet minimums in any case. Generally, the ponds were sized to hold the 50 and 100 year storms with 1-foot of freeboard above the 100-year event. The ponds are summarized in Table 2. Table 2. Pond Summary Table . . : ~SPOKANE COUNTYPOND INFORMATION . TOPOF PROVIDED ° MINIMUM BERM OTTOM BOTTOM TOP OF 50 YEAR B 50 YEAR DETENTION POND AREA . ELEVATION STRUCTURE DETENTION DETENTION VOLUME ELEVATION ELEVATION (SF) . ' VOLUME PROVIDED (CF -=A1 ~ 675 ~ 2181.83 ~ 2182.28-1 2182.83 ~ 1083 ~ 1425_ A2 ~ 675 ~ 2181.83 ~ 2182.28 ~ 2182.83 ~ 1083 ~ 1425 B ~ 450 ~ 2207.00 ~ 2207.47 . ~ 2208.10 ~ 483 2035 C ~ 450 ~ 2207.00 ~ 2207.47 ~ 2208.10 483 ~ 2035 D ~ 415 ~.2226.50 ~ 2227.63 ~ 2227.60 ( 758 ~ 1815 E ~ 415 ~ 2226.50 ~ 2227.63 ~ 2227.60 ~ 758 ~ 1815 F ~ 462 ~ 2221.46 ~ 2221.99 ~ 2222.66 ~ 292 ~ 1158 G ~ 462 ~ 2221.46 ~ 2221.99 ~ 2222.66 ~ 292 1158 H ~ 462 ~ 2186.16 ~ 2187.26 ~ 2187.26 ~ 830 2484 I ~ 462 ~ 2186.16 ~ 2187.26 1 2187.26 ~ 830 2484 J ~ 398 ~ 2161.75 ~ 2162.25 1 2162.85 ~ 232 ~ 943 K ~ 398 ~ 2161.75 ~ 2162.25 ~ 2162.85 ( 232 943 L ~ 600 ~ 2157.47 ~ 2157.97 ~ 2159.37 ~ ~ 1671 . - ~ ~ ~ . F - I ~ - . . -CITY,OF SPOKANE VALLEY PONb INFORMATION REQUIRED DETENTION, BOTTOM BOTTOM STRUCTURE TOP BACK DETENTION VOLUME POND AREA ELEVATION ELEVATION OF CURB VOLUME AT PROVIDED (SF) STRUCTURE AT CURB (CF)-~ (CF) , A1 A ' 98 ~ 2175 ~ 2175.5 ~ 2176 ~ 49+ ~ 49+ A2A ~ 98 ~ 2175 ~ 2175.5 ~ 2176 ~ 49+ ~ 49+ Whipple Consulting Engineers Page 24 of 26 Mica vieiv C of E- Drainage Report HYDRAULICS As noted eariier, the pass through pipes on this project were sized to accommodate the full 100-year event. Discharge from the pond structures are sized for the 2 and 50-year release rates. While the minimum culvert pipe size for Spokane County is 12-inch, discharge pipes are sized according to the Hydraflow program and generally are 4- inches in diameter. As the storm water catchments on this project are the roadside swales, velocities for the 50-year storm for each basin were checked at the steepest slope along the roadway reach and are included for reference and summarized in Table 3 below. Table 3 Roadside Swale 50-year Velocities . : ::-SPOKANE COUNTII IfVFORMATION POND RATE (CFS) ' SLOPE (FT/FT) - DEPTH OF FLOW RESULTING ~ ' . - - (FT) VELOCITY (FPS) A1 ~ 0.47 ~ 0.0941 0.20 ~ 2.41 A2 0.47 ~ 0.0941 0.20 ~ 2.41 B 0.47 ~ 0.0737 ~ 0.21 ~ 2.19 C ~ 0.47 ~ 0.0737 ~ 0.21 ~ 2.19 D ~ 0.48 ~ 0.0267 ~ 0.25 ~ 1.51 E ~ 0.48 ~ 0.0267 ~ 0.25 ~ 1.51 F ~ 0.21 0.0153 0.21 ~ 0.99 G ~ 0.21 ~ 0.0153 0.21 ~ 0.99 H ~ 0.52 ~ 0.0500 ~ 0.23 ~ 1.95 I ~ 0.52 ~ 0.0500 ~ 0.23 ~ 1.95 J ~ 0.25 ~ 0.0800 0.16 1.94 K ~ 0.25 ~ 0.0800 0.16 ~ 1.94 Whipple Corrstclting Engineers Page 25 of 26 Miccr View C of E- Drainage Report c CITY OF.SPOF(ANEYALLEY. INFORMATION POND RATE (CFS) SLOPE (FT/FT) DEPTH OF FLOW~ RESULTING (FT) . VELOCITY (FPS . A1 A ~ 0.34 ~ 0.0941 ~ 0.17 ~ 2.22 A2A ~ 0.34 ~ 0.0941 ~ 0.17 ~ 2.22 Based upon Tab(e 24-2, page 6-56 af the Spokane County Guidelines for Storm Water - Management, the resulting velocities shown in Table 3 of this document are below the permissible velocities for the Cover noted as Grass Mixture which has permissible velocities of befinreen 3 and 4 fps. CONCLUSION . Based upon the information provided and the calculations performed we believe that this report surnmarizes and demonstrates that the detention and release design method for this project is adequate to detain and release the increase in storm water runofffrom this project. Based upon these assertions, we believe that the implementation of the storrn water control systems discussed here and as shown on the accompanying plans will meet or exceed the storm water requirements of Spokane County. Whipple Consultirrg Engineers Page 26 of 26 Mica Vieiv C of E- Drainage Reporl O APPENDIX 1. Vicinity Map 2. Soil Conservation Service, Spokane County, Site Exhibit (Soils map) 3. Offsite Pass Through Basin Map (11x17)(Full Size in Jacket at End) 4. Pre Developed Basin Map (11x17)(Full Size in .lacket at End) 5. Post Developed Basin Map (11x17)(Full Size in Jacket at End) 6. On Site Basin Summary Sheet 7. Basin Calculation Worksheets (Spokane County / COV) 8. Pass Through Basin - Hydrograph Calculations 9. Pass Through Basin - Pipe Calculations 10. On Site Pre Developed - Hydrograph Calculations 11. On Site Post Developed - Hydrograph Calculations 12. On Site Post Developed - Pond Reports 13. On Site Post Developed - Pond Volume Calc Sheet - 50 Year Elevation Volumes 14. On Site Post Developed - Pond and Outlet Structure Design Sheets 15. Roadside Svvale - Triangular Channel Worksheets for Velocity and Depth . 16. Pipe Calculations for Froude Number and Velocity for Rip Rap Design 17. Rip Rap Design Spreadsheets 18. All West - Geotechnical Evaluation 19. All West - Proposal for Construction Inspection 20. Copy of Letters in Response to Comments Received on Submittal No. 1 21. Copy of Letters in Response to Comments Received on Submittal No. 2 22. Copy of Letters in Response to Comments Received on Submittal No. 3 ~UL't:/31/'LUU.ti 15: `33 !''Ab 5094't7765`J sYUtlA1VL{ (:UU1V1'Y t:1Vla1Nt,L:Kb lfLj UUt . ~ . . Fai Transmittal o ~ SwIfQW. Development Services Departnent Division of Engineering and Raads . (509) 477•3600 ' Fax (509) 477-7655 Date: August 31, 2005 , To: Todd Vhipple, P.E. Fax-No: 926-0227 Company: WCE cc: Bruce Howard Faz No: 924-9728 From: Tim Schwab Number of Pages: 3 incl. cover Subject: CE9105 - Mica'tTiew Certificafe of Exemption Attached i.s our comment letter for the Mica View Certif cate of Exemption, 3rd submittal. If you want, we can meet with you to discuss these comments. If you have any questions please give me a call. Tim Schwab cc: Project File U25/31/'LUUS 15:53 r'A.2i 5U94'17'1655 ,YURAlvrl I:UUN'1'Y tivvltvhhtcJ ttxj uuz . ° . ; . ' ~ gP O g{ A l~T 1-:7 , CC) U N T Y ~ DMSION OF FNaNEERIHG AND ROADS ` A DMSION OF THE PUBLIC WORKS DEPARTMiEiVT i . ~ August 31, 2005 ' ~ Mr. Todd Whipple, P.E. Vahipple Consulting Engineers 13218 East Sprague Ave. ' Spokane Valley, WA 99216 ~ ~ ~ Subject CE 91-05 1Vlica'View Cet '-tifiicaYe of txemption Road and.Drainage Plan Submittal #3 ! s Mr. Whipple, ~ . ; We have reviewed your subnuttal of fihe road and drainake design documents we received on August 23, 2005 for the Mica View C. of E. project. Before the Cettif cate of Exernption can be accepted, the private . road proposed to serve the lots must meet the current de4ign standards. 3'hc following items need to bs . addressed or resolved prior to acceptance of the plans: ' PLANS : 1, The pand bottoms as shown in the plans will not wark with the constant 5:1 -slope from edge of : pavement to bottom of swale alang with the grade of the road. Either show that the slopes vary or revise pond bottom area to show tb.e flat area thit can be constructed. 2. Provide a trash rack far all culverts greater than 18". Include a detail. ' . ; 3. The plans show inadequate volume for 208 trea ent for Basins J& K. 4. In the typical section detail, show the cut-off di h. : 5. We recommend that you record a blanket drainAge easement for the natural drainage areas. : fi. On Sheet 3, the centerline station elevation list is incorrect. The edge of asphalt grades le$ and : . right at Sta. 61+25 and Sta. 62+50 don't match e 2% slope from the centerline grade. 7. The Spokane County acceptance block should ave preliminary an it or be put on a non printing. : layer until ready for mylars to avoid potential nfusion over acceptance of plans. ; 0 pRAINAGE REPORT • 8. Per requirements for detention basins on page 3 6 of the GSM, a 10 year storm design storm is to . be evaluated as weil as the 2 year and 50 year design storms. It appears most of the calculations • have been performed. Include in your report turrative a summary table wifh the 2,10 and 50 year design storms, pre-developed vs. post-develop from the pond for each basin so it is shown that ~ for each of these de+sign starms in each of the b ins, the rats in the post-developed conditivn is less than or equal to the rate in the pre-develaped c ndition. - 9. The predomitnant soil type for this site is Type soil. From Table 5 on page 6-8 of the GSM, the ; lawest value for Type C soil is 70 fbr forest la it with good ground cov+er. The Drainage Report , claims a CN value for existing of 66. Also we lieve your post-developed CN value is calculated I incorrectly and is also low. However, the diff nce beivveen CN values is rougbly similar and . . therefore we will accept you're the calculatiousing these CN values. In future submittals, • ` consider CN values that more appropriately fit soil types and land uses. 1026 W. Sroadway Ave. m Spokane, WA 99260-0170 s(509) 477-3600 FAX: (549) 477-7655 (2nd Floor) 4717478 (3rd Floor) o't'pD; (509) 477-7133 09/31/2005 15:54 FA% 5094777655 WYUxAtvZ I:UUN'1']f L'1Vli1Nrt3Ko ~uua 10. Show how storm water at the end of Pie3rce Lane'north of Basins J& K is treated and detained. Include drainage calculations and plan edits. 11. In final Drainage Regort, include alI items as listed in the Appendix and are mentioned in the report such as full sized basin maps and photos. 12. The ponds sizes shown in the drainage report and:the plans do not agree in size. Check all prnnds to make sure the size of jond in the arainage report, the size claimed on the swale detail block and the actuai size of the pond shown in the plans all agree. , 13. For the raad and impervious axea north of Basins A1 and AZ, we will accept the recomsnendations regarding treatrnent and disposal from the City of Sgokane Valley. MLSCELLANEOUS ' You have indicated that these wili be submitted at a tater date, but are mentioned for reference. 14. It appears that construction is proposed in these plans for the.connection to Pierce Road that is outside the existing 70' Road and Utility easement area. P7ease provide a copy of the easements to allow this construction ar revise the plans to fit within existing easement 15. 'i'he drainage facilities that lie outside of the existing 70' private road and utility easement (Auditor's Document Number 5194998) axe required to be placed within easernents. The easements shall meet the requirements of the Stornawater Guidelines. Pleas$ provide the following docunaentation so we can prepare the easements: a. Plat certificate: Deed, Deed of Trust, or Conveying Instrument (recorded copy); b. List of signatory names; c. Legal description exhibit of the easement area: Include a title "Exhiibit A", it shall be . stamped by a licensed Suiveyor, aIl margins shall be I " or greater, 8 point rninimum fant sizs, and the text shall be reproducible; and, d. Easement area exhibit Include a title "Exhibit B" and meet the requirements of the legal description exhibit. 16. Provide afire district approval letter. 17. Provide a maintenance rnanual and sinking fund calculation.s. 18. Provide a draft capy of the CC&Rs along with the Homeowner's Association UBI#. If you have any questions aboufi this review, please contact us at 477 3b00. Sixmcerely, . Matt Zarecor, P.E. Developm,ent Services EngineerlManager A zja Ti.m Schwab, P.E. Plan Review Bngineer ce: Bryan Walker, Ovvner File z~ ~ ►re +I ;t! • • ~ l3 • CiT1' ,~r ~~^_N : ~ w _ ' ` Ulley 11707 E Sprague Ave Suite 106 ♦ Spokane Valley WA 99206 509.921.1000 ♦ Fax: 509.921.1008 ♦ cityhall@spokanevalley.org September 6, 2005 Todd Whipple, P.E. Whipple Consulting Engineers 13218 E. Sprague Avenue Spokane Va11ey, WA 99216 . Re: Mica View C of E(SF-OI-OS) Street & Drainage Submittal #3 Comments Todd, . On August 23, 2005 Public Works received your third submittal of the street and drai.nage plans. Please update the following items on your next submittal: Plan Sheets 1. On Sheet 5, please further detail the swale. This sha11 include the width, length, and top of berm elevations. I suggest you add berms in the swale to slow the flow and allow further treatment. 2. Please remove the approval starnp from plan subrnittals. This is reserved for the FINAL mylar only. ~ Drainage Report 1. Your report indicates a required volume of each swale to be 49 c.f.; however on page 19 it states 40 c.f. Please upda.te. 2. Please submit drywell testing i.nformation for the proposed Type A drywells located in the swales. The only soil testing information given near the proposed location is not acceptable for drywells. Prior to acceptance this information shall be subnutted, reviewed and accepted, 3. Your report states galleries are to be used in the swales a.nd ponds; however they are no indicated in the pia.ns. Please update the plans or the drai.nage report. 4. It appears there are numerous manholes/catch basins that do not have the required 0.75 feet freeboard. Please revise to meet this requirement. Once this information is submitted, further review can occur. Other items may occur at the review of the next submittal. An entire drainage report is not required, only the items changed from the previous submittal. Please contact me at 688-0174 for any additional questions. SinceAely, Sandra R.askell, P.E. Development Engi.neer cc: Bryan Walker - Property Owner . Matt Zarecor - Spokane County Engineeri.ng Division Department of Public Works - Development Project File WHIPPLE CONSULTING ENGINEERS , POND VOLUME CALC SHEET 911512005 2004-19 Mlca View C of E's 16 by TRW Besins Ponds Boliom (do of Ddvewey Bottom Squared.. Pond. Outiet Top of , Conic . Side Total • CoNc Side Total , . Area Driveways Area:@, Area : Side' • Bottom ' Pipe IE Berm • Volume to Slope Volume to . Volume Slope Valume • .160 sf: less Drive . Elevatiorr: Elevation ElevaUon IE of Ouilet Pipe Volume. Pipe IE Elev. to Top of Berm Volume to Top of Berm • sf ea sf sf . If- . ' ' . cf cf cf cF cf cf I I I~~ I I 7~ I I I I I I I A1A I swale . I 80 I 0 I 0 I 601 7.751 2175.001 2175.501 2178.001 301 121 421 601 461 106 I I I I I ~ I I I I I I I I I A2A I swale I BO I 0 I 0 I 601 7.751 2175.001 2175.501 2178,001 .301 121 42 601 461 106 I I I I I I I I I I I I I I A1 I A1 I 710 I 0 I_ 0 I 7101 26.651 2183.541 2184.041 2185,041 3551 401 3951 10851 3601 1425 I I I I I I I I I I I I I I A2 I A2 I 710 I 0 I 0 I 7101 26.651 2183.541 2184.04 -2185,041 .3551 40I 3951 10851 3601 1425 I I I I I I I I I 1 I I I I I 6 I -B I 700 I 0 I 0I 7001 26.461 -2207.00I:- 2207.50I 2209,001 3501 401 3901 14001 6351 2035 I I I I I I I I I I I I I I I C I C I 700 I 0 -I 0 I 700I 26.461- 2207.001 2207.501 2209.001 350I 401 3901 14001 8351 2035 I I I I I I I I I 1 I I I I I 0 I D 935 I 0 I 0 I 9351 30.581 2228.50 2227,00 2228.001 4681 461 5131 14031 4131 1815 I I I I I i I I I I I I E I E ~ 935 I0 I 0I 9351 30.581 2226.50 2227,001 2228.00 .4681 46I 5131 14031 4131 1815 I I I I I I I I I I I I I I F I F I 462 I 0 I 0 I 462I. 21,491 2221.481 2221.961 2223.181 2311. ,321 2631 7851 3731 1158 I I I I I I I I I I I I I I I G I G I 462 I. 0 I 0 I 4621 21.491 2221.461 2221.961 2223.161 2311321 263I 7851 3731 1158 I I I I I I I I I I I I I I I H I H.I 1120 I 0 I 0.1 11201 33.47I 2186,16 2166.661 2187.861. 5601 501 6101 19041 5801 2484 I I I I I I I I l I I I I I I I I I 1120 I 0 I 0:I 11201 33,471 -2186.161. 2186.661 2187.861 5601 501 6101. 19041 5801 2484 I I I I I I I I I I I I I ~ J I J ~ 398 1 .0' 1 0 1 . 3981 19,951 2160.951' 2161.461 ' 2162.561 ' 1991 301 2291 6371 308 943 I I I I ( I ~ I I I I I I I I K I K I 398 I 0 I 0 I 3981 19.951 2160.951 '-2161.451 2162.55 1991 301 2291 6371 3061 943 1 I I I I I I I 1 I I I I I Cul-de•sac I L I 800 I 0 I0 I • 600I 24.491 2157.471 2157.871• 2159.371 3001 371 3371 11401 5311 1671 1 I I I I I I I 1 I I I I I ~ Tofals ( I I I I 9.370.001 1 I I I 4.685,001 535.761 5.220.761 15,647.4015.957.401 21,604,80 1 11 PEAK FLOW CALCULATION PROJECT; Mica View C of E BOWSTRING METHOD PROJECT: Mlca View C of E 50-Year Design Storm °DETENTION BASIN DESIGN BASIN: End Cul-de•Sac DESIGNER BNG ' BASIN: End Cul-de•Sac DATE: 12-Sep-05 . Tot. Area 11,642 SF 0.27 Acres .Time Increment (min) 5 Imp. Area 6,930 SF C= 0.9 Tfine of Conc. (min) 5.00 Perv. Area 4,712 SF C= 0.15 Outflow (cfs) 0.3 Wt. C= 0.60 208 Area = 6930 Design Year Flow 50 Area (acres) 0.27 CASE 1 .~-Impervious Area (sq ft) 6930 ' - . 'C' Factor 0.60 10 ft. Overland Flow . •~Area' C 0.159 ' Treatment Area 6,930 Ct = 0.15 L= 10 ft. . Tfine Time Inc. Intens. Q Devel. Vol.ln Vol.Out Storage n = 0.40 • (min) (sec) (inlhr) (cfs) (cu ft) (cu ft) (cu ft) S= 0.0200 5.00 300 4.58 0.73 293 90 203 Cul Tc = 1.11 min., by Equation 3•2 of Guidelines 5 300 4.58 0.66 264 90 174 10 600 3.21 0.46 322 180 142 50 ft. Gutter flow ••15 900 2.44 0.35 350 270 80 20 1200 1.98 0.28 -369 360 9 Z1 = 50.0 ForZ2 . 25 1500 1.68 024 385 450 •65 Z2 = 50.0 Type 6=1.0 30 1800 1.46 021 397 540 -143 n= 0.016 Rolled = 3.5 35 2100 1.30 0.19 409 630 •221 S= 0.0300 40 2400 1.18 0.17 422 720 -298 45 2700 1.08 0,16 435 810 -375 d= 0.0860 ft. Flow Width 4.3 ft. 50 3000 1.01 0,14 447 900 -453 55 3300 0.94 0,13 458 990 -532 . 60 3600 0.88 0.13 467 1080 -613 A R Q Tc Tc total I Qc 65 3900 0.83 0,12 477 1170 -693 0.37 0.04 0.73 0.42 5.00 4.58 0.73 ..~70 4200 0,79 0,11 489 1260 -771 75 4500 0.77 0.11 507 1350 -843 Qpeak for Case 1= 0.73 cfs . r 80 4800 0.75 0,11 529 1440 -911 85 5100 0,73 0.11 547 1530 -983 " .90 5400 0.70 0.10 550 1620 -1070 , .95 5700 0.68 0.09 546 1710 -1164 CASE 2 ' 100 6000 0.88 0.10 594 1800 -1206 Case 2 assumes a Time of Concentratlon less than 5 minutes so that the "208" TREATMENT REQUIREMENTS peak flow =,90(Tc=5 intensity)(Imp. Area) = 0.86 cfs Minimum "208" Volume Required 289 cu ft Provided Treatment Volume - Minimum 300 cu ft DRYWELL REQUIREMENTS - 50 YEAR DESIGN STORM So, the Peak flow for the Basin is the greater af the lwo flows, ; Maximum Storage Required by Bowstring 203 cu ft 0.73 cfs ;Provided Storage Volume to Inlet - Minumum 300 cu ft ' Number and Type of Drywells Required 1 Single • • 0 Double r ' • PEAK FLOW CALCULATION PROJECT: Mica View C of E :BOWSTRING METHOD PROJECT: Mica View C of E ° 10-Year Design Storm DETENTION BASIN DESIGN BASIN: End Cul-de-sac DESIGNER; BNG ' BASIN: End Cui-de-sac DATE: 12-Sep-05 Tot. Area 11,642 SF 0.27 Acres Imp. Area 6,930 SF C= 0.90 , Time Increment (min) 5 Per, Area 4,712 SF C= 0.15 Time of Conc. (min) 5.00 Wt, C 0.60 208 Area = 6930.00 . Outflow (cfs) 0.3 - . Design Year Flow 10 CASE 1 : Area (acres) 0.27 . , Impervious Area (sq ft) 6930 10 ft. Overland Flow :'C Factor 0.60 . Area' C 0,159 Ct = 0.15 - . Asphaltic Area 6,930 , L = 10 ft. • ' n= 0.40 Time Time Inc. Intens. Q Devel. Vol.ln Vol.Out Storage S = 0.0200 . (min) (sec) (inlhr) (cfs) (cu ft) (cu ft) (cu ft) 5.00 300 3.18 0.51 204 90 114 Tc = 1.11 min., by Equation 3-2 of Guidelines 5 300 3.18 0.45 183 90 93 50 ft. Gutter flaw ..10 600 2.24 0.32 225 180 45 15 900 1.76 025 252 270 -18 Z1= 50.0 For Z2 - 20 1200 1.45 0.21 271 360 -89 Z2 = 50.0 Type B=1.0 . 25 1500 1.23 0.18 282 450 -168 n= 0.016 Rolled = 3.5 30 1800 1.05 0.15 286 540 -254 S= 0.0300 35 2100 0.91 0.13 287 630 -343 40 2400 0.81 0.12 290 720 -430 d= 0.0750 ft. Flow Width 3.8 ft. 45 2700 0.74 0.11 297 810 -513 50 3000 0,69 0.10 306 900 -594 55 3300 0,65 0.09 316 990 -674 A R Q Tc Tc total I Qc .~'60 3600 0.61 0.09 325 1080 -755 0.28 0.04 0.51 0.46 5.00 3,18 0.51 65 3900 0,58 0.08 335 1170 -835 ~ 70 4200 0,56 0.08 348 1260 -912 Q peak for Case 1= 0.51 cfs 75 4500 0.55 0.08 365 1350 -985 80 4800 0.55 0.08 385 1440 -1055 ' 85 5100 0.53 0.08 398 1530 -1132 ' 90 5400 0.50 0.07 392 1620 -1228 CASE 2 95 . 5700 0.45 0.06 375 1710 -1335 100 6000 0.49 0.07 429 1800 -1371 Case 2 assumes a Time of Concentratlon less than 5 minutes so that the peak flow =.90(Tc=5 intensity)(imp. Area) = 0.45 cfs '"208" TREATMENT REQUIREMENTS • Minimum "208" Volume Requiretl 289 cu ft Providetl Treatment Volume - Minimum 300 cu ft , So, the Peak flow for the Basin is the greater of the two flows, DRYWELL REQUIREMENTS -10 YEAR DESIGN STORM 0.51 cfs ` Maximum Storage Required by Bowstring 114 cu ft Provided Storage Volume - Minimum 300 cu ft Number and Type of Drywells Requlred 1 Single ' 0 Double , ~ . , Hydraflow Plan View p Ousfall Oidfafl Oultali Ouifail autfall 1 5 11 2 14 G 3 7 8 9 10 Project file: Pass Through Basins.stm No. Lines:11 09-13-2005 HydraDow Slorm Sewers 2003 . • ~ Page 1 - ~ Storrn Sewer Summary Report • Line Line ID Flow Line Line Invert Invert Line HGL HGL Minor Dns No. rate size length EL Dn EL Up slope down up loss line (cfs) (in) (ft) (ft) (ft) N (ft) (ft) (ft) No. 1 Pass Through A 6.49 24 c 24.0 175.33 177.10 7.375 176.23 178.00 0.05 Eqa 2 Inserted Line 5.59 24 c 62.0 177.10 177.41 0.500 178.33 178.63 0.02 1 3 inserted Line 5.49 24 c 19.0 177.41 180.00 13.632 178.66 180.83 0.31 2 4 Pass Through B 2.89 24 c 122.0 203.44 204.05 0.500 204.04 205.18 0.04 End 5 Pass Through C 3.70 24 c 40.0 205.89 209.61 9.300 206.57 210.29 0.04 End 6 inserted Line 3.20 24 c 62.0 209.61 209.91 0.484 210.46 210.76 0.01 5 7 Inserted Line 2.70 24 c 18.0 209.91 215.00 28.278 210.78 215.58 0.20 6 8 Pass Through D 2.50 24 c 210.0 217.29 218.36 0.510 217.85 219.59 0.00 End 9 Inserted Line 2.00 24 c 90.5 218.36 218.76 0.442 219.60 219.67 0.00 8 10 Inserted Line 1.50 24 c 15.9 218.78 222.91 25.975 219.67 223.34 0.14 9 11 Pass Through E 2.11 12 x 60 b 100.0 100.00 102.00 2.000 100.18 102.18 0.09 End Project File: Pass Through Basins.stm Number of lines: 11 Run Date: 09-13-2005 NOTES: c= circular, e= ellipUcal; b= box; Return period = 100 Yrs.; " Indicates surcharge condition. Hydraflow Storm Sevrers 2003 Storm Sewer Profile Proj, file: Pass Through Basins.stm ~ d Elev. (ft) ~ Lr 197.00 . . , „ . . . . . , . _ 192.00 Ln: ~ . . ____,._,.A_,..,. (M) ~ 157.00 Ln:1 Ln- ~I 24 (in) 24 / 182.00 „ . _ ~j_.~...~_~,.• j._.._.._.._._....,,,__., 177.00 172.00 0 10 20 30 40 50 60 70 80 90 100 110 Reach (ft) Hydraflow Storm Sewers 2003 ~~orm Se~rer ~rof~ I~ Proj, fiile: Pass Tt~rough B2~sins stm + ~ E1ev. (ft) 216.00 213.00 , - ~ 24 (ir,).,.~..,~.r 210.00 , - - ~ ..,e,o,,..,,.,,,,..,m,,,. . „ . . . . . . . . . . . . . . 207.00 i _ . . , - ~ . . . . . 204,00 ~ i 241.OD o 10 20 30 40 50 60 70 80 90 100 110 120 1 30 - Reach {ft} Hydraflaw Skorm 5ewers 2003 Storm Sewer Prvfiie Proj. file; Pass Through Basins.stm ~ 1- + Elev. (ft) 238,00 _ ,,,,,,,W,,,, - - - - - ,,,,,,,,,,,,,,,,,,y... . „ , , , . „ , . . , . 233.00 - - ~ Ln: 10 ~ . „ 24_ { in} 228.0{} 3 , 24,,(in) , , , , 24 (in) , , , 223.00 - , r- ~ .~..~W.;::;;;:,Y.X,,,.i,,, . 0 218.0 .,,,,,,,,.m....~_..,,... . , 213.00 0 25 50 75 100 125 150 175 200 225 250 275 300 325 Reach (ft) Hydraflaw 5torm 5ewers 2003 Storm Sewer Profile Proj. file: Pass Through Basins.stm ~ P l~ ~ ~ Elev. (ft) 236.00 . . . . . . . . . . _ . . . . . . . . „ . , , . . . , . . „ , 229.00 ~ _ a.. . . , .._..1..,.,...,,,,. _Ln:,4 24 (in) . ~ _ 222.00 ~ Ln: 6 Ln:-5 24 (in) 24 (i_.~~~.____,~...... , ~ . ~ . _ _ . . . _ . _ , ~ . . m....__,....., - - - _ , . _ _ 215.00 ~ _ = - - - - - ~ . - ~ - _ ► - ~u_~a=- 208.00 ~ : _ _ . _ 201.00 0 10 20 30 40 50 60 70 80 90 100 110 120 Reach (ft) . Hydraflow Storm Sewers 2003 Storm Sewer Profile Proj. file: Pass Through Basins.stm ~ ~ 4 Elev, (ft) 117.00 - __._W.~.~e _ 113.00 . . . . . . . . . . , , . ~ Ln:11 109.00 . . . . . . ..0 . . . , . . 1.2...,X ...6(n)...:.:...::.::._._... . . . __.._:;W:;., . . . . . . . . . . . . . . , . . . . . . . . . , . . . . . _ ~ ~ ~ . _ _ . . . . . ~ . _ ~ _ _ 105.00 . . . . . . . . . . . , . , . . . . . . . . . . . 7> ~ -i , . ~ .ti_ . _I........ . , _W_ - 101.00 ~ _........,,_......_m_._... . . _ .,.mm. . . _ . . . . . _ . . . . . . , . . , . , . . . . . . , , . _ .:mm .W . . ~ .T.._~.:._ . 97.00 I 0 10 20 30 40 50 60 70 80 90 100 Reach (ft) Hydraflow Storm Sewers 2003 • ~ f