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Ex#14 Geotechnical Evaluation Drainage Report OptimizedCONCEPT DRAINAGE REPORT FOR THE PONDEROSA RIDGE EAST SUBDIVISION Spokane Valley, Washington December 2022 WCE W.O. No. 2020-2798 Prepared by: Whipple Consulting Engineers, Inc. 21 S. Pines Road Spokane Valley, WA 99206 Whipplece.com This report has been prepared by the staff of WCE under the direction of the undersigned professional engineer whose seal and signature appear hereon. Todd R. Whipple, P.E. GENERAL The proposed Ponderosa Ridge East Preliminary Plat proposes the development of 81 residential lots ranging in size from approximately 5,150 ft2 to over 10,000 ft2 located on approximately 16.95 acres. The site lies within the City of Spokane Valley, WA, south of and adjacent to 44th Avenue and west of Farr Road. The site lies in the Nl/2 and NWl/4 of section 5, T 24 N., R 44 E., W.M., and is located within the aquifer sensitive area. A vicinity map is attached. The project proposes to extend 45th Avenue and 47th Avenue into the plat from Farr Road and construct a north/south Locust Road with connections to the Ponderosa Ridge Phase 1 and future phase along 46th A venue and 4gth A venue. The Ponderosa Ridge plat is in Spokane County and was an approved preliminary plat that expired and is again under application to complete. PURPOSE The purpose of this concept drainage report is to determine the storm drainage facilities that will be required to treat and dispose of the increase in stonn water runoff created by development of the vacant lands for the new development. The facilities will be designed to treat and dispose of the 2, 10, 25, 50 and 100-year storms or as required by the SRSM, for this analysis, as a concept stonn report, we are only verifying that the 100 year storm event can be maintained on site. Stormwater generated by this development will be collected in catch basins and pipes and treated in bioswales and discharged via gravel galleries or other types of injection systems such as ADS Stonntech type infiltrators, etc... The reviewer should note that due to roadway slopes greater than 2%, no roadside swales will be provided, only planting strips. The Intensity, Duration, and Frequency (IDF) curves from the Spokane, Medical Lake, Reardon, Cheney and Rockford intensity curves as modified by the Spokane Regional Storm Manual (SRSM) are used for bowstring calculations to detennine basin flows for reference for the Rational stonn. The 2, 10-, 25-, 50-and 100-year rainfall intensity iso-pluvials from the Spokane Regional Stonnwater Manual have been used for both the TR-55 and HEC-22 calculations for the HydroCAD storm water model. ANALYSIS METHODOLOGY The Rational Method, which is recommended for basins less than ten acres in size, should be used to determine the peak discharges and runoff volumes for all onsite basins. All off-site basins and all on-site basins larger than ten acres will use the SCS Method to detennine peak discharge and runoff volumes. For this Concept Stonnwater Analysis, the SCS Method as analyzed in the HydroCAD Stormwater Modelling program version 10.20-2f ( 40 node version) has been used. Additionally, one small basin north of 45th Avenue will use the rational method was used. Because of the hillside nature of this development, all ponds and facilities have been conceptually designed for the 100 year event. Additionally, in 2014 for the County Ponderosa Ridge project, a portion of 47th Avenue between the County project and Farr Road was to be extended for a 2nd access for that plat. At that time a Whipple Consulting Engineers Page 2 of8 Ponderosa Ridge East -Concept Drainage Report design along with a stonn drainage report was prepared and approved by the City of Spokane Valley. The County plat expired and 47th Avenue was not constructed, the associated design was somewhat cumbersome at that time and because of such and because quite a bit of detailed investigations were included as a part of that design, that report for the easterly portion of 47th is included in the appendix as a part of this analysis. TOPOGRAPHY The site is considered a rolling terrain site with existing slopes on site ranging averaging between 10% and 15% sloping down to 44th A venue from the south to the n01ih with varying levels east and west. As shown on the preliminary plat map, the proposed road system will follow contours, while the roads will be graded north and south the east/west slope orientation will be maintained for stonn water flows to generally follow the lay of the land. SOILS As can be seen from the USDA, Soil Conservation Service (SCS) soils repo1i as and as supplemented in a 2014 Inland Pacific Engineering Company geotechnical analysis for 47th A venue, for the noted second access and water booster station for the expired Ponderosa Ridge (Spokane County) project. The soils are noted below. At the time of final design, additional geotechnical evaluations will be made to confirm the homogenous aspects noted in the SCS soils map. Per the reports attached, the soil classification for this site per the are as follows: 3121-Marble loamy sand, 8 to 15 percent slopes. 7121-Urban land-Marble, disturbed complex, 3 to 8 percent slopes. 7121-Urban land-Marble, disturbed complex, 8 to 15 percent slopes All soils on site have the following hydrologic soil classification. Hvdrologic Soil Classification -A/B Per the geotechnical evaluation and test pits, the soils approaching 44th A venue were deeper well drained soils that may allow drywell type discharge solutions, however, other test pits have indicated weathered bedrock at 6 to 8 feet, it is the intent to use the ADS -Stormtech infiltrators until such time as an updated geotechnical investigation can be completed and additional infiltration tests observed to validate any confining layers that may or may not be present. Whipple Consulting Engineers Page 3 of8 Ponderosa Ridge East -Concept Drainage Report DRAINAGE NARRATIVE BASIN SUMMARY -Pre-Developed (HydroCAD Pre-Basin A) The existing site is 16.95 Acres in size. The drainage from this basin is generally from SE to NW with no observed drainages other than sheet flow operating as a shallow concentrated type of flow, as discussed in the SCS manual. For this project the pre-developed CN =65 for Woods/Grass combination, fair (light understory), HSG B, by using this value at CN=65 for the pre-developed analysis, it will result in larger storage volumes as it will provide a greater percentage of change, which is generally how the SCS method evaluates the storage as a change in percentage between the pre and post after the initial abstraction is removed. a e . re-eve o pe asm ummary a T bl 1 P D l d B . S T bl e Area ac) SCS Rate ( cfs) Basin Imp Pervious Off site Total 2-yr 10-yr 25-yr 50-yr 100-yr A 0 16.95 0 16.95 0.03 0.14 0.40 0.57 0.76 BASIN SUMMARY -Post-Developed Narrative The post developed site is divided into three basins, Basins A, B and C for analysis in the Concept Storm Report as shown on the attached basin map. Following are nan-atives on the various basins and sub-basins and where and how the water is treated and discharged. It should be noted that the two basins A and Bare generally separated at 45111 Avenue and Locust Road, wherein runoff south of 45th A venue is in Post Basin A which will be directed into Pond A and Post Basin Bis that part of Locust laying north of 45th Avenue discharging into Pond B. Post Basin C is a part of a previously analyzed basin on 47th Avenue and is expected to be developed as was originally approved and therefore, the stonn drainage analysis from that time period is attached as reference in this Concept Storm Drainage Report. At the time of final design, a fully updated drainage report for all Post Basins A, B and C will be combined into a final design report. Basin A (HydroCAD Post Basin A and Pond A (Hydrocad Labels 28, 4P and 6P) This basin while smaller than the pre-developed basin, is as described earlier and mimics the pre- developed basin A in that it collects drainage from the developed condition via pipes and catch basins from the SE to the NW and discharges in Pond A. All developed roads except for a portion of the easterly end of 47th Avenue (Basin C) and the two stub roads 46th and 43th A venues, are included in this basin. Pond A will be located at the NE quadrant of 45th A venue and Locust Road intersection. Whipple Consulting Engineers Page 4 of8 Ponderosa Ridge East -Concept Drainage Report For Post Basin A the following summarizes the intent of the overall design. • All runoffs will be captured in catch basins and routed to Pond A via a piped system. • All stormwater in Pond A will be treated by 12-inches of treatment soil and then discharged to the underlying infiltrators. The discharge orifice will be located in a proposed catch basin and will be 4-inches in size to match the outflow from the infiltration gallery. • At the time of construction, a split ring infiltration test will be conducted to confirm the discharge at that time and will be included in the final design. • For this analysis, it was presumed that all generated stormwaters will be maintained on site, with no offsite or intra-basin routing. • Proposed Pond A as proposed will have a 9,249 sf pond bottom, approximately 25,881 cf of pond storage, two inlets to the storm tech chambers and a chamber field using ADS Stormtech SC-740 chambers 7 rows wide by 6 chambers long, with a discharge rate of 0.44 cfs. Storage will remain in the pond and discharge to the chambers over time, however less than 72 hours. Basin B (100 year-Stormtech -Bowstring Analysis) This basin is part of Locust Road north of 45th Avenue and has been sized to store, treat, and discharge the 100 year event. For Post Basin B the following summarizes the intent of the overall design. • All runoffs will be captured in catch basins and routed to Pond B via a piped system. • All sto1mwater in Pond B will be treated by 12-inches of treatment soil and then discharged to the underlying infiltrators. The discharge orifice in a proposed catch basin will be 2 to 4-inches in size to match the outflow from the infiltration gallery. • At the time of construction, a split ring infiltration test will be conducted to confirm the discharge at that time and will be included in the final design. • For this analysis, it was presumed that all generated stormwaters will be maintained on site, with no offsite or intra-basin routing. • Proposed Pond Bas proposed will have a 4,440 sf pond bottom, approximately 14,540 cf of pond storage, two inlets to the storm tech chambers and a chamber field using ADS Stormtech SC-740 chambers 4 rows wide by 6 chambers long, with a discharge rate of 0.38 cfs. Storage will remain in the pond and discharge to the chambers over time, however less than 72 hours. Whipple Consulting Engineers Page 5 of8 Ponderosa Ridge East Concept Drainage Report Table No. 2 -Pond and Basin Summary SCS -POND BASIN INFORMATION SUMMARY CN Values CN Values 100-Year Req'd 100 -Year Area Pre-Post-Discharge Storage Basins (AC) Developed Development Rates Volumes (cfs) (ac-ft I ct) Pre Post A 13.26 65 75 0.76 6.00 0.467 ac-ft I 20,343 cf B 2.27 SRSM SRSM n/a 3.12 0.016 ac-ft I 683 cf c See Attached St01m Drainage Report from 2014 Totals 16.46 0.76 9.12 0.483 ac-ft I 21,040 cf POND DESIGN Ponds A and B will be sized to hold the 100-year stonn with at least one foot of freeboard, as currently proposed due to hillside development. Table No. 3 100-yr Pond Volume Summary 100-yr Storage Volume (ft3) Pond Required Provided Bottom Elevation 100-yrWSEL A 20,343 cf 25,881 cf 2185 2186.95 B 683 cf 14,539 cf 2160 2060.61 As can be seen, proposed Pond A and B, both have the ability to store and treat the 100-year stonn with no downstream discharges. CONCLUSION This report demonstrates that the SCS and Rational methods when combined can capture, detain, treat and discharge the proposed storm water design for this system to meet SRSM requirements. Per Page 3-6 of the SRSM, there are additional items that need to be addressed these areas are as follow: Critical Area Discussion: • There are no wetlands present on site • There are no DNR streams on site Whipple Consulting Engineers Page 6 of8 Ponderosa Ridge East -Concept Drainage Report • The soil types are Type A/B and should not be considered "erodible soils" • There are no identified susceptible species present on site • The site is in the Aquifer Sensitive Area and high susceptibility area of CARA Perpetual Maintenance of Facilities: The proposed storm drainage system will be a system of pipes and catch basin in public roads and as such will be owned by the Jmisdiction. The ponds, while part of the public system, will be maintained in Tracts within the plat and will be maintained by the project HOA. Offsite Easements: None are required at this time; however, some easements may be necessary for utilities or access with the Ponderosa Ridge (County) project to the west, but these will be pursued at time of final design. Regional Facilities: This project is not a part of any Spokane County or City of Spokane Valley regional system. Whipple Consulting Engineers Page 7 of8 Ponderosa Ridge East -Concept Drainage Report APPENDIX • VICINITY MAP • PONDEROSA RIDGE EAST PRELIMNINARY PLAT • BASINMAP • PRELIMINARY POND MAP • COUNTRY 3RD ADDITION FINAL PLAT • HYDROCAD PRE AND POST BASIN A CALCULATIONS • 100 YR-SRSM-BOWSTRING BASIN B CALCULATIONS • BASIN C PREVIOUS DRAINAGE REPORT • IPEC GEOTECHNICAL EVALUATION CA. 2014 • SCS SOILS REPORT Whipple Consulting Engineers Page 8 of8 Ponderosa Ridge East -Concept Drainage Report 44TH. AVENUE 0 4'. 0 er: er: w 1---------i LL 4'. :::r: () (/)1-------,- PRO.J #: 21-2798 DATE: 03/03/21 DRAWN: CTR APPROVED: TRW FIGURE 1 I DRAINAGE REPORT PONDEROSA RIDGE ADD. SPOKANE VALLEY, WASHINGTON VIC::: IN ITY MAP I _J_ s NOT TO SCALE ~WCE WHIPPLE CONSUL TING ENGINEERS 21 SOUTH PINES ROAD SPOKANE VALLEY, WASHINGTON 99206 PH: 509-893-2617 FAX: 509-926-0227 l1zoTM@ fiNTE~ ft~~ ~./f?f &~MIJJ~Lf t:l.AT , • i ~ I! @""'NAVO -88 r~x PAPCEL# 4532"" 9084 ~-..... ------ w > <{ I ~ <:t ' ' - PAPCEL# 4405:'. 9086 N2' 29' 19"W 20.17' PAPCEL# d40':'I: 91r PARCEL# 4405'.? 917F 2~ ''-'('1 IQ..!{, 40 lei.:; I "' l~O _,~ 1wo 1"--'C'I 10..l{• ~o a.::;. PO N DEROSA \ \ / -- ' '-; / PRELIMINARY PLAT PONDERDSA RIDGE EAST LOCATED IN A PORTION OF N 1 /2, NWl /4, SEC. 05, T. 24 N., R . 44 E., W.M. SPOKANE VALLEY, WA I c \<s 1~0 :i., 1d 1~f· ~c _,c I _,. i::~ wo wO w O '~' ('j LI r1 l ~~I~~ "-"' I-10...u. <o 4 Q u_~ a.:; o..:; "-~ -~-LN -______,_ \ ~E. ' I ' r1P.. --'· ' E:.? -' p~ \ ' f<I \ \ ' \ ------ / / / / --- / I / / I r \ I .-; / I I I I \ I I I I I I 10 IQ'.. I 1Z ____ J<{ 2: ----·_j 10 \I I I I I I I I I I I I I I I I I I I r I I I I I I I I \ I I I I I I I I \ I I I I I r I I I I I I I I I I VICINITY MAP SITE DATA TABLE PARCEL NUMBER 44052.9011 PROJECT ZONE R3 MAX ZONING DENSITY (8u/oc) 135.62 SF AC PROJECT AREA 738,478.03 16.95 RESIDENTIAL LOT AREA 550,737.12 12.64 TRACT AREA 52,731.92 1.21 RIGHT OF WAY AREA 135,008.99 3.10 MIN. LOT AREA 5,149.29 0.12 MAX. LOT AREA 10,200.17 0.23 NUMBER OF LOTS 81 NUMBER OF TRACTS 6 OCCUPANCY SINGLE FAMILY IMPERVIOUS AREA 264,609 I 6.07 WATER SERVICE PROVIDER SPOKANE COUNTY WATER DISTRICT #3 SEWER SERVICE PROVIDER I SPOKANE COUNTY FIRE DISTRICT I SPOKANE VALLEY FIRE DISTRICT SHEET INDEX PP1 PRELIMINARY PLAT COVER PP2 PRELIMINARY PLAT PP3 PRELIMINARY PLAT SITIE PLAN PP4 PRELIMINARY PLAT ROAD SECTIONS PPS PRELIMINARY PLAT PLAN AND PROFILE (LOCUST & 45TH) PP6 PRELIMINARY PLAT PLAN ANO PROFILE (46tH, 47th & 48th) PP7 44TH AVENUE ASPHALT PATH EXHIBIT (FARR RO. TD WOODRUFF RD.) GRAPHIC SCALE 100 0 50 100 200 ~--I I I ( IN FEET ) 1 inch = 100 ft. ENGINEER WHIPPLE CONSUL TING ENGINEERS 21 SOUTH PINES SPOKANE VALLEY, WA 99206 PHONE< 893-2617 CONTACT< TODD R. WHIPPLE, P.E. LEGAL DESCRI PTIDN PARCEL NUMBER 44052.9011 05-24-44 TR "D" OF SP92-746 AUD #9212170413 BK 9, PG 8 BEING A PTN OFNW1/4 EXC PTN OAF< BEG AT MOST SELY COR SD TR ·o· TH N 89DEG59MIN 45SDS w ALG s LN SD TR ·o· 164.40FT TH N ODEG 09MIN21 SOS E 265FT TH S 890EG 59MIN 45SDS E 164.40FT TO NWLY CORTR "A" SP79-144 TH S ODEG 09MIN 21 SOS W ALG W LN TR "A" 265FT TO POB FROM SPOKANE SCOUT SO I LS DESCRI PTIDN 3121-MARBLE LOAMY SANO, 8 TO 15 PERCENT SLOPES 7121-URBAN LAND-MARBLE, DISTURBED COMPLEX, 3 TO 8 PERCENT SLOPES 7122-URBAN LAND-MARBLE, DISTURBED COMPLEX, 8 TD 15 PERCENT SLOPES ' I '.; 60, ' ' f<C ,iQ~ i:>P-' 6! ' \ ' -' ' \ \ >-· ' __ ,-i I __ , I I I \ I SURV EYOR WHIPPLE CONSUL TING ENGINEERS 21 SOUTH PINES CRITICAL AREAS: I I I I -' < -v PRELIMINARY PLAT SCALE (H< 1·~100· / --"-' ' ' _,___ "--' -' -------->-- A 212012 sn ORIGINAL PREPARATIONS NO. DATE BY REVISIONS ---I I r . I / __ , SCALE: PROJ #: 20-2798 HORIZONTAL: DATE: 10/27/22 1"=100' DRAWN: SLS VERTICAL: REVIEWED: TRW N/A I I I I I ( I I I I I I I I I I I CML ~WCE STRUCTURAL SURVEYING TRAFFIC X PLANNING WHIPPLE CONSUL TING ENGINEERS LANDSCAPE 21 S. PINES ROAD OTHER SPOKANE VALLEY. WA 99206 PH 509·893·2617 FAX· 509·92&0227 SPOKANE VALLEY, WA 99206 PHONE< 893-2617 1. CITY OF SPOKANE VALLEYYRIORITY-HABITAT-SPECIES-MAP< ROCKY MOUNTAIN ELK CONTACT< DAVID COWELL, P.LS. O WNER LANZCE G. DOUGLASS INVESTMENTS, LLC 1402 E. MAGNESIUM STIE 202 SPOKANE, WA 99217 PHONE< 483-6532 CONTACT< LANZCE DOUGLASS NORTHWEST WHITIE TAIL DEER PLANS NOT APPROVED BY AGENCY PONDEROSA RIDGE EAST PRELIMINARY PLAT COVER 44TH AVE & FARR RD SPOKANE VALLEY, WA SHEET PP1 JOB NUMBER 20-2798 I FARR RD w > <l'. I ~ <:!' " " m m oo om ID <in ID<"'• NNN NNr.:- O>!l Oil' m m "' t'- " -- ' " m " <:!'~~ m ~ -[r) ~~ N~oi-N"":oi: ON o-"' t'-in >!) PRELIMINARY PLAT LAYO UT SCALE (H): 1"=60' ~NAVO-88 xxxx " m o"' N<in N'":i= O<t 0 >!) EXISTING TERMINUS TO BE EXTENDED 36 0.2 AC: 8756. l 6 SF" 35 0.2 AC 8506.54 !?F 34 0.2 AC 781 7.80 SF \ 33 0.2 AC 9349.87 SF -,.------ " " " m m m o_ Din I•, I /' . I • I I o I I I ~I I I J ----/ -. 'm 'o cri •Iii_ o~lii (J\•m -•o N-·= N'":ai= r-'"':00:: i---:o:i-·"' O<t O<t O<t <o~ '"' "' "' in in \tn in \ A 212s12 sn NO. DATE BY 37 \ 0.1 AC 6225.57 SF / • 1' 39 , 0.1 AC \ I ~169.16 SF _-,.-- --- " m o_ I' •m r-'":cri:: O<t "' in " m o_ ID <m ...---:tri:: O<t "' in ORIGINAL PREPARATIONS REVISIONS N~, NW;J:, SEC.05, T.24N., R.44E., W.M. TRACT uO" 0.2 AC 6913.54SF,~ 55" 0.3 AC "' 1 l 60.99 SF - PROPOSED 47TH AVE ' / I \ / I TRACT "E"l 0.4 AC I 16146.82 SF\"' I • J J - SCALE: PROJ #: HORIZONTAL: DATE: 1"=60' DRAWN: 11 , I I VERTICAL: REVIEWED: N/A ' TRACT "F'' 0.1 AC 3710.24SF" 7'2 0.2 AC 8241 ,87 SF' I' 73 0.2 AC 8091i3.95 SF I ;74 0.2 AC 758,6. 1 1 SF '75 1D.2 AC 6859.33 SF I • \ 76 I ! 0.1 AC ! 6528.64 SF 78 0.1 AC 6246.34 SF' CIVIL 20-2798 STRUCTURAL 10/27/22 SURVEYING TRAFFIC SLS X PLANNING LANDSCAPE TRW OTHER ~WCE WHIPPLE CONSULTING ENGINEERS 21 S PINES ROAD SPOKANE VALLEY. WA 99206 PH 509-89J.2617 FAX 509-926-0227 2 1 O' REAR YARD SEIB ACK -__ L __ UNDERGROUND SERVICE Al£RT ~:1cr: ~ IEFOR£ YOU DIG 5' SIDE YARD '--- SEIBACK r 15' FRONT YARD SEIB ACK (20' TO GARAGE) 5' SIDE YARD OR 15' FLANKING SEIB ACK TYPICAL LDT SETBACK DETAIL z NOT TO SCALE = w $ UJ 5: 0.1 AC 6533.21 SF GRAPHIC SCALE 60 0 30 60 120 .... ~I I I r I I ( IN FEET ) 1 inch = 60 ft. PLANS NOT APPROVED BY AGENCY PONDEROSA RIDGE EAST PRELIMINARY PLAT 44TH AVE & FARR RD SPOKANE VALLEY, WA SHEET PP2 JOB NUMBER 20-2798 \! ~""'NAVO-88 ~ xxxx ~ N~, NW;k, SEC.OS, T.24N., R.44E., W.M. 'i. f-----------------------------------------60" ROW-----------------------------------------J Tr''"~~--r I ·-~' ! "~ I 'l""'i~1T >:"'~'ti;,:,~ r-. L'=i~::sc::,o ice'.."'0f~" ~~~l:~~~-;;'_::_:::::~"::':~~:~:::~~~-~.S:::~~:f=~J-~-l ~.~~% ~ PLAN R-103 3• HMA CLASS j. PLAN R-103 j" ON 6" CSBC TYPICAL ROAD CROSS SECTION NOT TO SCALE TYPE "B" CURB ANO GUTTER PER STANDARD PLAN R-102 TYPICAL ROAD CROSS SECTION NOT TO SCALE I- I I I I I I I I I I I I I I I I 10' UTILITY EASEMENT TYPICAL ROAD CROSS SECTION NOT TO SCALE 10' UTILITY EASEMENT 11' BORDER EASEMENT 3" HMA CLASS l" ON 6" csBc 3" HMA CLASS j" ON 6" CSBC 2'__,c----------15'---------~--------15'---------+-2' SIDEWALK PER STANDARD PLAN R-103 TYPICAL ROAD CROSS SECTION NOT TO SCALE A NO. 2128/2 STT DATE BY ORIGINAL PREPARATIONS REVISIONS 3" HMA CLASS j" ON 6" CSBC SCALE: HORIZONTAL: AS SHOWN VERTICAL: N/A ClVIL PROJ #: 20~2798 STRUCTURAL DATE: 10/27/22 SURVEYING TRAFFIC DRAWN: SLS X PLANNING LANDSCAPE REVIEWED: TRW OTHER c 11' BORDER EASEMENT SIDEWALK PER STANDARD PLAN R-103 ~WCE WHIPPLE CONSULTING ENGINEERS 21 S PINES ROAD SPOKANE VALLEY. WA 99206 PH 509-893-2617 FAX 509-926·0227 D B 10' UTILITY EASEMENT -----1 I I I I I I I I I I I I I I I I UNDERGROUND SERVICE A1£RT ~:1cr: ~ llEFOA£YOODIO PLANS NOT APPROVED BY AGENCY PONDEROSA RIDGE EAST PRELIMINARY PLAT DETAILS 44TH AVE & FARR RD SPOKANE VALLEY, WA SHEET PP4 JOB NUMBER 20-2798 ---r-- FARR RD I w > <l'. I ~ '1" E ISllN Ev; R TO BE J ABANDONED AND REPLACED, EASEMENT TO BE VACA TED PRELIMINARY PLAT LAYOUT SCALE (H), 1 "-60' ~ :;~ NAVD-88 ';; xxxx i N A 2128/2 STT ORIGINAL PREPARATIONS NO. DATE BY REVISIONS N~, NW,J:, SEC.05, T.24N., R.44E., W.M. I - SCALE: HORIZONTAL: 1·=60' VERTICAL: N/A PROJ #: DATE: DRAWN: ,....,\' l I I 20w279B 10/27/22 SLS REVIEWED: TRW ~~~~c .. '_,URAl ~WCE , ,su~NG TRAFFIC X PLANNING LANDSCAPE OTHER \h/HIPPLE CONSULTING ENGINEERS 21 S PINES ROAD SPOKANE VALLEY, WA 992{)6 PH 509.SgJ.2617 FAX 500·926·0227 5" SIDE YARD SETBACK 10' REAR YARD SETBACK L._ -r 15" FRONT YARD SETBACK (20' TO GARAGE) UNllERGROUHO SERVICE ALERT tSk\ ::a:u: ~-""'"" 5' SIDE YARD OR 15' FLANKING SETBACK TYPICAL LDT SETBACK DETAIL NOT TO SCALE w _z_====-.-ti$:t-m ~ GRAPHIC SCALE 60 03060 5-? I I ( IN FEET ) 1 inch = 60 ft. PLANS NOT APPROVED BY AGENCY PONDEROSA RIDGE EAST PRELIMINARY PLAT 44TH AVE & FARR RD SPOKANE VALLEY, WA 120 ~ SHEET PP3 JOB NUMBER 20-2798 / / ' ' ---~-J - --,< / ---- / \ \ 8 -- IT I I /, ' ' I I - @. ~ -,uu•, ACT 2290 2280 2270 2260 2250 2240 2230 2220 2210 2200 2190 2180 2170 2160 ' 2150 10+00 """NAVO-88 xxxx ---\ \ -. -··----, \ ' I \ \ §Ji 6'1· 8 I I \~+uu -- 11+00 12+00 ' ' " ', \·~~! \ i \ \ \ I ! \ \ ',L I \ \ ·.=:i-:::-'_;.-·?-·--·--------~::---_1-::-_c -____ ' - '.\ i ~ i i! 1: I --. i ,! \, ·-I \ \ s \ '• -~ \ i ~ \ \ I © @ @ @ © I @ § \§ @ \8 @ @ I \ \ \ ---+o ,_ v-"' ' 1T -~ I~ ~ @ I ~\ ' \ I - '1 '.I \ @-@ ~~ l l \@ @ '1 I @ - I I, ( I @ -@ I I @ @ \ ,,_ @ \ I I I @ I§ ,--~--® I, .,..-I I ! § -1-@ I I I @1 @ @) --I @ --§ <Z1 I \ ~I I I @ -® I I @ ---~# \ ~ '"' \ @ i,n I I ' -@ .,._ la \ l \ ~\ @ ~ \\\ I@ " '---. '---. PROPOSED FG EG f ..___ ..___ -....;: .__,,, N~, NW;j:, SEC.05, T.24N., R.44E., W.M. I ',: l \ \ ·-\-1 \ : I --_cc-=-= -r------~ :--~---_ \ \ ~ I I I I i \ I ITRAI ® @l @, ® § IT -@ '@ IN @:··_ I \ \ -~ ~\ I ·--· '" --=-~ ----' ""' f-----.:. ~ --U-_ TRACT J ------ I·-II @ I I ! l ---@~, \ ® I ---l §) --@ -~ I 8 I $::= UJ ~--z- LOW POINT STA;=21+50.21 LOW POINT EL.=2173.15 PVI STA.=20+30.21 PVI EL.=2177,95 · K=40.00 AD=6.00% 240.00'VC I I I I I- ") \ J ·--j'\ I\ .,. ------,,.;3 _,_,, -,, ' "°' ( -----· d ''I Ii ---- 2290 2280 2270 2260 2250 2240 2230 2220 2210 2170 '2160 13+00 14+00 15+00 16+00 17+00 18+00 19+00 2o+OO 21+00 22+00 23+00 2150 2'2ll003 GRAPHIC SCALE 100 0 50 100 ~-I I 200 I --( IN FEET ) 1 inch = 100 ft. A 212s12 sn NO. DATE BY ORIGINAL PREPARATIONS REVISION SCALE: HORIZONTAL: 1~=100' VERTICAL: N/A PROJ #: DATE: DRAWN: REVIEWED: 20-2798 10/27/22 SLS TRW 2240 223~ I~ 0 "' 222~ ~;::; II 11 11 221% ~~ <f)UJW 2200 2180 2170 10+00 11+00 12+00 HIGH POINT STA.=14+24.05 HIGH POINT EL.=2208.87 PVI STA,=14+24.05 13+00 PVI EL.=2218.47 K=30.00 AD=-16.003 480.00'VC 14+00 15+00 17+00 16+00 17+00 FDR REFERENCE ONLY 18+00 18 82 2240 2190 2180 2170 18+00 18+82 PLANS NOT APPROVED BY AGENCY CIVIL STRUCTURAL SURVEYlNG TRAFFIC 1-+----t ~WC E PONDEROSA RIDGE EAST PRELIMINARY PLAT PLAN & PROFILE 44TH AVE & FARR RD X Pl.ANNING LANDSCAPE OTHER WHIPPLE CONSUL TING ENGINEERS 21 S PINES ROAD SPOKANE VALLEY. WA 99206 PH 509·893-2617 FAX 509·925-0227 SPOKANE VALLEY, WA s SHEET PP5 JOB NUMBER 20-2798 <2ID aID Gill 02) 9J) CID @ 00 @ I -• .. " ri "' ;;; II ~~ UlW 2260 2260 2250 2250 224-0 2230 2220 oO 2241§ ~ 00 i g 6~ " 223~ II .:&:; ~ 222ct; ;;j 2210 2200 2190 14+00 15+00 16+06+34 ] ~ 2210 ~ i ~ ~ 2200 i! '.> ~ ' ~ 2190 § 10+00 11+00 12+00 13+00 GRAPHIC SCALE 100 0 50 100 ~-I I ~ s~ NAVO-88 ? xxxx : 200 I --( IN FEET ) 1 inch = 100 ft. A 212s12 sn NO. DATE BY ) D or ~ ~ 0 .. ~~~ 22 2270'1 II" "' ~~ UlUlW 2260 224-0 2230 2220 2210 10+00 11+00 12+00 ORIGINAL PREPARATIONS REVISIONS HIGH POINT STA.=12+80.74 HIGH POINT EL.=2254.31 PVI STA.=13+40.74 PVI EL.=2259.11 K=30.00 AD=-12.00% 360.00'VC 13+00 14+00 15+00 16+00 SCALE: HORIZONTAL: 1"=100' VERTICAL: 1~=20' 17+00 18+00 PROJ #: DATE: DRAWN: REVIEWED: 2270 -~ ~260 "' Oi ·;}; "2250 ~ul 11 "' ~24-0 Ul w 2230 ~220 2210 18+82 20~2798 10/27/22 CIVlL STRUCTURAL SURVEY1NG TRAFFIC SLS X PLANNING LANDSCAPE TRW OTHER 5 2290 2280 2270 2260 o" oO 22~~ 0 22~ 11 .,,&:; .... ~ 2230" w 2220 '\ 2210 2200 2190 10+00 11+00 L1WCE WHIPPLE CONSULTING ENGINEERS 21 S PINES ROAD SPOKANE VALLEY. WA 99206 PH 509·693-2£17 FAX 509-926-0227 I I / r l 15+00 J--I I ' I PROPOSED PONDEROSA RIDGE PH 2 ______J. . . . . . UNDER SEPARATE APPLICATION . : . j __.... __.... ·1 (-~/-­ r' 1® I I 2280 2270 5 2260 PROPOSED FG I I I 2250 224-0 2230 2220 2210 2200 2190 12+00 13+00 14+00 15+00 16+00 17+00 17+99 FOR REFERENCE ONLY PLANS NOT APPROVED BY AGENCY PONDEROSA RIDGE EAST PRELIMINARY PLAT PLAN & PROFILE 44TH AVE & FARR RD SPOKANE VALLEY, WA SHEET PP6 JOB NUMBER 20-2798 N~, NW~, SEC.05, T.24N., R.44E., W .M . OVERVIEW SCALE• NOT TO SCALE CIVIL SCALE: PROJ #: 20-2798 STRUCTURAL SURVEYING HORIZONTAL: DATE: 10/27/22 TRAFFIC -0 NAVO -88 xxxx NTS DRAWN: SLS X PLANNING A 212012 sn ORIGINAL PREPARATIONS VERTICAL: LANDSCAPE REVIEWED: TRW OTHER NO. DATE BY REVISIONS N/A / / / / / / / / / / / / / / / / T r 5'1 ASPHA~~ PAlH-l-1---'--VARIES h::;:::;;::;:=~:::;;:~---, 1~[J,f~h-.U<.~1~·~-*··'l,l>. L:-,i ~~W.~ri·,, _ 2' RIP-RAP LINED V-DITCH TYPICAL ROAD CROSS SECTION E NOT TO SCALE PLANS NOT APPROVED BY AGENCY ~WCE PONDEROSA RIDGE EAST 44TH ASPHALT PATH EXHIBIT 44TH AVE & FARR RD SPOKANE VALLEY, WA WHIPPLE CONSUL TING ENGINEERS 21 S. PINES ROAD SPOKANE VALLEY. WA 99206 PH 509·893-2617 FAX 509·926-0227 SHEET PP7 JOB NUMBER 20-2798 \WCE_WORK\2020WCE PROJECTS\2020-2798 L. Douglass-Ponderosa COSV New\DWG\2798-BASIN MAP.dwg, 1/3/20231:12:06 PM, sschutz, AutoCAD PDF (General Documentation).pc3 / rnf/:t!Jf.j: ... ~~~ ,,,0 \\"-\ '\.:' ~',, '~\\:' N ~ .... en I l"1 l"1 -I '--.. ... ""'•. \, ' . '\ ,, : / / 1 ' ,I;! \~~/// / _......, i;\\\cV'>· . t? ! "'\, / \ ', ''\ /:/'/ . • 'I. .. 1// I /""' • ./\J; l ''----t I 01 I ~ \• l . ..---,...,.. I ,/ ,,.,.,. :x/ "-.L I 1 ~, !. I) / ~L;\\ ,,__---.... / ~ /-~ <\ /v·.// so\, /\/. ,.----<:::i •• / / . / / I \ / -1 /,...,.. / L.V·>· /~/ / ;. ·./I 1 •/ / . :i.>1.J ·1"co / i v ! I I I / ~ ' \ \ ;, \. ! .. ' . '-... '····· '"',,_ .,.~* ... ~\ '\ \ \ \ "'-,, '\ \ ""',,,, \'. \ .\ \ \ \ --2260--- - - --......_ ~·~·260= --~ .... ,_ ---2265-"-...... --,...,.. " -/ ""-----'\ \ \. \ ....... ( \ \ \ ) j I ( \ "-... " ' J \ \_ --PRE-DEVELOPMENT BASIN MAP PON DEROSA RIDGE ADD C::ONC::EPT STORM PRO.J#: 21-27981 ~WCE DATE: D 1 /03/23 DRAWN: STAFF APPROVED: TRW SPOKANE VALLEY, WASHINGTON WHIPPLE CONSULTING ENGINEERS CIVIL , STRUCTURAL AND TRANSPORTATION ENGINEERING 21 SOUTH PINES ROAD SPOKANE VALLEY, WASHINGTON 99206 PH: 509-893-2617 FAX: 509·926-0227 "' u q. c: .9 -:;; c "' E a 0 Cl I I : I !1 i~i I POND A 9,249 sf BOTTOM EL: 2185.00 25,881.93 cf @ 2.44' DEPTH BASIN A BASIN B BASIN C TOTAL AREAS BASIN DATA SF AC 577,412.52 13.26 61,555.94 1.41 78, 112.28 1.79 717,080.74 16.46 --I \ "' '"-.. - / ~/ SHEET 2 OF 2 1S 2798 Pre Dev Basin A 2S 2798 Post Dev Basin A 3R Pipe System to Pond 5R Pipe to Infiltrators 4P Concept Pond for Sizing and Discharge 6P Infiltration Basin Routing Diagram for 2798 - Concept StormPrepared by Whipple Consulting Engineers, Printed 1/3/2023 HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Subcat Reach Pond Link L. Douglass - Ponderosa Ridge East - COSV 2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 2HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Rainfall Events Listing (selected events) Event# Event Name Storm Type Curve Mode Duration (hours) B/B Depth (inches) AMC 1 25 yr Type II 24-hr Default 24.00 1 2.20 2 2 100 yr Type II 24-hr Default 24.00 1 2.60 2 L. Douglass - Ponderosa Ridge East - COSV 2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 3HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Area Listing (all nodes) Area (acres) CN Description (subcatchment-numbers) 13.260 75 1/4 acre lots, 38% imp, HSG B (2S) 16.400 65 Woods/grass comb., Fair, HSG B (1S) 29.660 69 TOTAL AREA L. Douglass - Ponderosa Ridge East - COSV 2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 4HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Soil Listing (all nodes) Area (acres) Soil Group Subcatchment Numbers 0.000 HSG A 29.660 HSG B 1S, 2S 0.000 HSG C 0.000 HSG D 0.000 Other 29.660 TOTAL AREA L. Douglass - Ponderosa Ridge East - COSV 2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 5HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Ground Covers (all nodes) HSG-A (acres) HSG-B (acres) HSG-C (acres) HSG-D (acres) Other (acres) Total (acres) Ground Cover Subcatchment Numbers 0.000 13.260 0.000 0.000 0.000 13.260 1/4 acre lots, 38% imp 2S 0.000 16.400 0.000 0.000 0.000 16.400 Woods/grass comb., Fair 1S 0.000 29.660 0.000 0.000 0.000 29.660 TOTAL AREA L. Douglass - Ponderosa Ridge East - COSV 2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 6HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Pipe Listing (all nodes) Line# Node Number In-Invert (feet) Out-Invert (feet) Length (feet) Slope (ft/ft) n Width (inches) Diam/Height (inches) Inside-Fill (inches) 1 2S 0.00 0.00 300.0 0.0800 0.010 0.0 12.0 0.0 2 3R 2,270.00 2,186.80 1,040.0 0.0800 0.010 0.0 12.0 0.0 3 5R 2,186.00 2,180.00 20.0 0.3000 0.010 0.0 12.0 0.0 L. Douglass - Ponderosa Ridge East - COSV Type II 24-hr 25 yr Rainfall=2.20"2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 7HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Time span=1.00-48.00 hrs, dt=0.05 hrs, 941 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=16.400 ac 0.00% Impervious Runoff Depth=0.19"Subcatchment 1S: 2798 Pre Dev Basin A Flow Length=1,370' Slope=0.1245 '/' Tc=232.7 min CN=65 Runoff=0.40 cfs 0.265 af Runoff Area=13.260 ac 38.00% Impervious Runoff Depth=0.48"Subcatchment 2S: 2798 Post Dev Basin A Flow Length=500' Tc=38.8 min CN=75 Runoff=3.77 cfs 0.534 af Avg. Flow Depth=0.37' Max Vel=14.40 fps Inflow=3.77 cfs 0.534 afReach 3R: Pipe System to Pond 12.0" Round Pipe n=0.010 L=1,040.0' S=0.0800 '/' Capacity=13.10 cfs Outflow=3.75 cfs 0.534 af Avg. Flow Depth=0.07' Max Vel=10.60 fps Inflow=0.27 cfs 0.308 afReach 5R: Pipe to Infiltrators 12.0" Round Pipe n=0.010 L=20.0' S=0.3000 '/' Capacity=25.37 cfs Outflow=0.27 cfs 0.308 af Peak Elev=2,186.42' Storage=0.328 af Inflow=3.75 cfs 0.534 afPond 4P: Concept Pond for Sizing and Outflow=0.27 cfs 0.308 af Peak Elev=2,180.02' Storage=0.000 af Inflow=0.27 cfs 0.308 afPond 6P: Infiltration Basin Outflow=0.27 cfs 0.308 af Total Runoff Area = 29.660 ac Runoff Volume = 0.799 af Average Runoff Depth = 0.32" 83.01% Pervious = 24.621 ac 16.99% Impervious = 5.039 ac L. Douglass - Ponderosa Ridge East - COSV Type II 24-hr 25 yr Rainfall=2.20"2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 8HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Summary for Subcatchment 1S: 2798 Pre Dev Basin A Runoff = 0.40 cfs @ 15.81 hrs, Volume= 0.265 af, Depth= 0.19" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 1.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr 25 yr Rainfall=2.20" Area (ac) CN Description 16.400 65 Woods/grass comb., Fair, HSG B 16.400 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 222.6 300 0.1245 0.02 Sheet Flow, Sheet Flow Woods: Light underbrush n= 0.400 P2= 0.04" 10.1 1,070 0.1245 1.76 Shallow Concentrated Flow, Shallow Concentrated Flow Woodland Kv= 5.0 fps 232.7 1,370 Total Subcatchment 1S: 2798 Pre Dev Basin A Runoff Hydrograph Time (hours) 48464442403836343230282624222018161412108642Flow (cfs)0.44 0.42 0.4 0.38 0.36 0.34 0.32 0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Type II 24-hr 25 yr Rainfall=2.20" Runoff Area=16.400 ac Runoff Volume=0.265 af Runoff Depth=0.19" Flow Length=1,370' Slope=0.1245 '/' Tc=232.7 min CN=65 0.40 cfs L. Douglass - Ponderosa Ridge East - COSV Type II 24-hr 25 yr Rainfall=2.20"2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 9HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Hydrograph for Subcatchment 1S: 2798 Pre Dev Basin A Time (hours) Precip. (inches) Excess (inches) Runoff (cfs) 1.00 0.02 0.00 0.00 1.50 0.04 0.00 0.00 2.00 0.05 0.00 0.00 2.50 0.06 0.00 0.00 3.00 0.08 0.00 0.00 3.50 0.09 0.00 0.00 4.00 0.11 0.00 0.00 4.50 0.12 0.00 0.00 5.00 0.14 0.00 0.00 5.50 0.16 0.00 0.00 6.00 0.18 0.00 0.00 6.50 0.20 0.00 0.00 7.00 0.22 0.00 0.00 7.50 0.24 0.00 0.00 8.00 0.26 0.00 0.00 8.50 0.29 0.00 0.00 9.00 0.32 0.00 0.00 9.50 0.36 0.00 0.00 10.00 0.40 0.00 0.00 10.50 0.45 0.00 0.00 11.00 0.52 0.00 0.00 11.50 0.62 0.00 0.00 12.00 1.46 0.03 0.00 12.50 1.62 0.05 0.00 13.00 1.70 0.06 0.03 13.50 1.76 0.08 0.09 14.00 1.80 0.09 0.19 14.50 1.84 0.10 0.29 15.00 1.88 0.10 0.35 15.50 1.91 0.11 0.39 16.00 1.94 0.12 0.40 16.50 1.96 0.12 0.38 17.00 1.98 0.13 0.35 17.50 2.01 0.14 0.32 18.00 2.03 0.14 0.30 18.50 2.05 0.15 0.28 19.00 2.06 0.15 0.26 19.50 2.08 0.16 0.24 20.00 2.09 0.16 0.23 20.50 2.11 0.17 0.21 21.00 2.12 0.17 0.20 21.50 2.14 0.17 0.19 22.00 2.15 0.18 0.18 22.50 2.16 0.18 0.17 23.00 2.18 0.19 0.16 23.50 2.19 0.19 0.15 24.00 2.20 0.19 0.15 24.50 2.20 0.19 0.14 25.00 2.20 0.19 0.14 25.50 2.20 0.19 0.13 26.00 2.20 0.19 0.12 26.50 2.20 0.19 0.10 Time (hours) Precip. (inches) Excess (inches) Runoff (cfs) 27.00 2.20 0.19 0.08 27.50 2.20 0.19 0.06 28.00 2.20 0.19 0.04 28.50 2.20 0.19 0.03 29.00 2.20 0.19 0.02 29.50 2.20 0.19 0.02 30.00 2.20 0.19 0.01 30.50 2.20 0.19 0.01 31.00 2.20 0.19 0.01 31.50 2.20 0.19 0.00 32.00 2.20 0.19 0.00 32.50 2.20 0.19 0.00 33.00 2.20 0.19 0.00 33.50 2.20 0.19 0.00 34.00 2.20 0.19 0.00 34.50 2.20 0.19 0.00 35.00 2.20 0.19 0.00 35.50 2.20 0.19 0.00 36.00 2.20 0.19 0.00 36.50 2.20 0.19 0.00 37.00 2.20 0.19 0.00 37.50 2.20 0.19 0.00 38.00 2.20 0.19 0.00 38.50 2.20 0.19 0.00 39.00 2.20 0.19 0.00 39.50 2.20 0.19 0.00 40.00 2.20 0.19 0.00 40.50 2.20 0.19 0.00 41.00 2.20 0.19 0.00 41.50 2.20 0.19 0.00 42.00 2.20 0.19 0.00 42.50 2.20 0.19 0.00 43.00 2.20 0.19 0.00 43.50 2.20 0.19 0.00 44.00 2.20 0.19 0.00 44.50 2.20 0.19 0.00 45.00 2.20 0.19 0.00 45.50 2.20 0.19 0.00 46.00 2.20 0.19 0.00 46.50 2.20 0.19 0.00 47.00 2.20 0.19 0.00 47.50 2.20 0.19 0.00 48.00 2.20 0.19 0.00 L. Douglass - Ponderosa Ridge East - COSV Type II 24-hr 25 yr Rainfall=2.20"2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 10HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Summary for Subcatchment 2S: 2798 Post Dev Basin A Runoff = 3.77 cfs @ 12.41 hrs, Volume= 0.534 af, Depth= 0.48" Routed to Reach 3R : Pipe System to Pond Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 1.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr 25 yr Rainfall=2.20" Area (ac) CN Description 13.260 75 1/4 acre lots, 38% imp, HSG B 8.221 62.00% Pervious Area 5.039 38.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 38.1 50 0.0400 0.02 Sheet Flow, Front Yards Grass: Short n= 0.150 P2= 0.04" 0.4 150 0.0800 5.74 Shallow Concentrated Flow, Gutter to Catch Basin Paved Kv= 20.3 fps 0.3 300 0.0800 16.68 13.10 Pipe Channel, Catch Basin to Pipe 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.010 PVC, smooth interior 38.8 500 Total Subcatchment 2S: 2798 Post Dev Basin A Runoff Hydrograph Time (hours) 48464442403836343230282624222018161412108642Flow (cfs)4 3 2 1 0 Type II 24-hr 25 yr Rainfall=2.20" Runoff Area=13.260 ac Runoff Volume=0.534 af Runoff Depth=0.48" Flow Length=500' Tc=38.8 min CN=75 3.77 cfs L. Douglass - Ponderosa Ridge East - COSV Type II 24-hr 25 yr Rainfall=2.20"2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 11HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Hydrograph for Subcatchment 2S: 2798 Post Dev Basin A Time (hours) Precip. (inches) Excess (inches) Runoff (cfs) 1.00 0.02 0.00 0.00 1.50 0.04 0.00 0.00 2.00 0.05 0.00 0.00 2.50 0.06 0.00 0.00 3.00 0.08 0.00 0.00 3.50 0.09 0.00 0.00 4.00 0.11 0.00 0.00 4.50 0.12 0.00 0.00 5.00 0.14 0.00 0.00 5.50 0.16 0.00 0.00 6.00 0.18 0.00 0.00 6.50 0.20 0.00 0.00 7.00 0.22 0.00 0.00 7.50 0.24 0.00 0.00 8.00 0.26 0.00 0.00 8.50 0.29 0.00 0.00 9.00 0.32 0.00 0.00 9.50 0.36 0.00 0.00 10.00 0.40 0.00 0.00 10.50 0.45 0.00 0.00 11.00 0.52 0.00 0.00 11.50 0.62 0.00 0.00 12.00 1.46 0.15 0.48 12.50 1.62 0.21 3.60 13.00 1.70 0.24 1.55 13.50 1.76 0.27 0.89 14.00 1.80 0.29 0.65 14.50 1.84 0.31 0.52 15.00 1.88 0.32 0.46 15.50 1.91 0.34 0.42 16.00 1.94 0.35 0.37 16.50 1.96 0.36 0.33 17.00 1.98 0.37 0.31 17.50 2.01 0.38 0.30 18.00 2.03 0.39 0.28 18.50 2.05 0.40 0.27 19.00 2.06 0.41 0.25 19.50 2.08 0.42 0.23 20.00 2.09 0.43 0.22 20.50 2.11 0.44 0.20 21.00 2.12 0.44 0.19 21.50 2.14 0.45 0.19 22.00 2.15 0.46 0.19 22.50 2.16 0.46 0.18 23.00 2.18 0.47 0.18 23.50 2.19 0.48 0.18 24.00 2.20 0.48 0.18 24.50 2.20 0.48 0.10 25.00 2.20 0.48 0.02 25.50 2.20 0.48 0.00 26.00 2.20 0.48 0.00 26.50 2.20 0.48 0.00 Time (hours) Precip. (inches) Excess (inches) Runoff (cfs) 27.00 2.20 0.48 0.00 27.50 2.20 0.48 0.00 28.00 2.20 0.48 0.00 28.50 2.20 0.48 0.00 29.00 2.20 0.48 0.00 29.50 2.20 0.48 0.00 30.00 2.20 0.48 0.00 30.50 2.20 0.48 0.00 31.00 2.20 0.48 0.00 31.50 2.20 0.48 0.00 32.00 2.20 0.48 0.00 32.50 2.20 0.48 0.00 33.00 2.20 0.48 0.00 33.50 2.20 0.48 0.00 34.00 2.20 0.48 0.00 34.50 2.20 0.48 0.00 35.00 2.20 0.48 0.00 35.50 2.20 0.48 0.00 36.00 2.20 0.48 0.00 36.50 2.20 0.48 0.00 37.00 2.20 0.48 0.00 37.50 2.20 0.48 0.00 38.00 2.20 0.48 0.00 38.50 2.20 0.48 0.00 39.00 2.20 0.48 0.00 39.50 2.20 0.48 0.00 40.00 2.20 0.48 0.00 40.50 2.20 0.48 0.00 41.00 2.20 0.48 0.00 41.50 2.20 0.48 0.00 42.00 2.20 0.48 0.00 42.50 2.20 0.48 0.00 43.00 2.20 0.48 0.00 43.50 2.20 0.48 0.00 44.00 2.20 0.48 0.00 44.50 2.20 0.48 0.00 45.00 2.20 0.48 0.00 45.50 2.20 0.48 0.00 46.00 2.20 0.48 0.00 46.50 2.20 0.48 0.00 47.00 2.20 0.48 0.00 47.50 2.20 0.48 0.00 48.00 2.20 0.48 0.00 L. Douglass - Ponderosa Ridge East - COSV Type II 24-hr 25 yr Rainfall=2.20"2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 12HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Summary for Reach 3R: Pipe System to Pond Inflow Area = 13.260 ac, 38.00% Impervious, Inflow Depth = 0.48" for 25 yr event Inflow = 3.77 cfs @ 12.41 hrs, Volume= 0.534 af Outflow = 3.75 cfs @ 12.45 hrs, Volume= 0.534 af, Atten= 1%, Lag= 2.2 min Routed to Pond 4P : Concept Pond for Sizing and Discharge Routing by Stor-Ind+Trans method, Time Span= 1.00-48.00 hrs, dt= 0.05 hrs Max. Velocity= 14.40 fps, Min. Travel Time= 1.2 min Avg. Velocity = 6.67 fps, Avg. Travel Time= 2.6 min Peak Storage= 272 cf @ 12.43 hrs Average Depth at Peak Storage= 0.37' , Surface Width= 0.96' Bank-Full Depth= 1.00' Flow Area= 0.8 sf, Capacity= 13.10 cfs 12.0" Round Pipe n= 0.010 PVC, smooth interior Length= 1,040.0' Slope= 0.0800 '/' Inlet Invert= 2,270.00', Outlet Invert= 2,186.80' Reach 3R: Pipe System to Pond InflowOutflow Hydrograph Time (hours) 48464442403836343230282624222018161412108642Flow (cfs)4 3 2 1 0 Inflow Area=13.260 ac Avg. Flow Depth=0.37' Max Vel=14.40 fps 12.0" Round Pipe n=0.010 L=1,040.0' S=0.0800 '/' Capacity=13.10 cfs 3.77 cfs3.75 cfs L. Douglass - Ponderosa Ridge East - COSV Type II 24-hr 25 yr Rainfall=2.20"2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 13HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Reach 3R: Pipe System to Pond Primary Stage-Discharge Discharge (cfs) 14131211109876543210Depth (feet)1 0 Reach 3R: Pipe System to Pond Storage Stage-Storage Storage (cubic-feet) 8007006005004003002001000Depth (feet)1 0 L. Douglass - Ponderosa Ridge East - COSV Type II 24-hr 25 yr Rainfall=2.20"2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 14HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Hydrograph for Reach 3R: Pipe System to Pond Time (hours) Inflow (cfs) Storage (cubic-feet) Elevation (feet) Outflow (cfs) 1.00 0.00 0 2,270.00 0.00 2.00 0.00 0 2,270.00 0.00 3.00 0.00 0 2,270.00 0.00 4.00 0.00 0 2,270.00 0.00 5.00 0.00 0 2,270.00 0.00 6.00 0.00 0 2,270.00 0.00 7.00 0.00 0 2,270.00 0.00 8.00 0.00 0 2,270.00 0.00 9.00 0.00 0 2,270.00 0.00 10.00 0.00 0 2,270.00 0.00 11.00 0.00 0 2,270.00 0.00 12.00 0.48 49 2,270.11 0.26 13.00 1.55 147 2,270.24 1.65 14.00 0.65 78 2,270.15 0.66 15.00 0.46 61 2,270.13 0.46 16.00 0.37 53 2,270.12 0.38 17.00 0.31 47 2,270.11 0.31 18.00 0.28 43 2,270.10 0.28 19.00 0.25 40 2,270.10 0.25 20.00 0.22 36 2,270.09 0.22 21.00 0.19 33 2,270.08 0.19 22.00 0.19 33 2,270.08 0.19 23.00 0.18 32 2,270.08 0.18 24.00 0.18 31 2,270.08 0.18 25.00 0.02 7 2,270.03 0.02 26.00 0.00 0 2,270.00 0.00 27.00 0.00 0 2,270.00 0.00 28.00 0.00 0 2,270.00 0.00 29.00 0.00 0 2,270.00 0.00 30.00 0.00 0 2,270.00 0.00 31.00 0.00 0 2,270.00 0.00 32.00 0.00 0 2,270.00 0.00 33.00 0.00 0 2,270.00 0.00 34.00 0.00 0 2,270.00 0.00 35.00 0.00 0 2,270.00 0.00 36.00 0.00 0 2,270.00 0.00 37.00 0.00 0 2,270.00 0.00 38.00 0.00 0 2,270.00 0.00 39.00 0.00 0 2,270.00 0.00 40.00 0.00 0 2,270.00 0.00 41.00 0.00 0 2,270.00 0.00 42.00 0.00 0 2,270.00 0.00 43.00 0.00 0 2,270.00 0.00 44.00 0.00 0 2,270.00 0.00 45.00 0.00 0 2,270.00 0.00 46.00 0.00 0 2,270.00 0.00 47.00 0.00 0 2,270.00 0.00 48.00 0.00 0 2,270.00 0.00 L. Douglass - Ponderosa Ridge East - COSV Type II 24-hr 25 yr Rainfall=2.20"2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 15HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Summary for Reach 5R: Pipe to Infiltrators Inflow Area = 13.260 ac, 38.00% Impervious, Inflow Depth > 0.28" for 25 yr event Inflow = 0.27 cfs @ 18.37 hrs, Volume= 0.308 af Outflow = 0.27 cfs @ 18.36 hrs, Volume= 0.308 af, Atten= 0%, Lag= 0.0 min Routed to Pond 6P : Infiltration Basin Routing by Stor-Ind+Trans method, Time Span= 1.00-48.00 hrs, dt= 0.05 hrs Max. Velocity= 10.60 fps, Min. Travel Time= 0.0 min Avg. Velocity = 6.54 fps, Avg. Travel Time= 0.1 min Peak Storage= 1 cf @ 18.36 hrs Average Depth at Peak Storage= 0.07' , Surface Width= 0.52' Bank-Full Depth= 1.00' Flow Area= 0.8 sf, Capacity= 25.37 cfs 12.0" Round Pipe n= 0.010 PVC, smooth interior Length= 20.0' Slope= 0.3000 '/' Inlet Invert= 2,186.00', Outlet Invert= 2,180.00' Reach 5R: Pipe to Infiltrators InflowOutflow Hydrograph Time (hours) 48464442403836343230282624222018161412108642Flow (cfs)0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Inflow Area=13.260 ac Avg. Flow Depth=0.07' Max Vel=10.60 fps 12.0" Round Pipe n=0.010 L=20.0' S=0.3000 '/' Capacity=25.37 cfs 0.27 cfs0.27 cfs L. Douglass - Ponderosa Ridge East - COSV Type II 24-hr 25 yr Rainfall=2.20"2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 16HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Reach 5R: Pipe to Infiltrators Primary Stage-Discharge Discharge (cfs) 26242220181614121086420Depth (feet)1 0 Reach 5R: Pipe to Infiltrators Storage Stage-Storage Storage (cubic-feet) 1514131211109876543210Depth (feet)1 0 L. Douglass - Ponderosa Ridge East - COSV Type II 24-hr 25 yr Rainfall=2.20"2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 17HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Hydrograph for Reach 5R: Pipe to Infiltrators Time (hours) Inflow (cfs) Storage (cubic-feet) Elevation (feet) Outflow (cfs) 1.00 0.00 0 2,186.00 0.00 2.00 0.00 0 2,186.00 0.00 3.00 0.00 0 2,186.00 0.00 4.00 0.00 0 2,186.00 0.00 5.00 0.00 0 2,186.00 0.00 6.00 0.00 0 2,186.00 0.00 7.00 0.00 0 2,186.00 0.00 8.00 0.00 0 2,186.00 0.00 9.00 0.00 0 2,186.00 0.00 10.00 0.00 0 2,186.00 0.00 11.00 0.00 0 2,186.00 0.00 12.00 0.00 0 2,186.00 0.00 13.00 0.00 0 2,186.00 0.00 14.00 0.20 0 2,186.06 0.20 15.00 0.24 0 2,186.07 0.24 16.00 0.26 0 2,186.07 0.26 17.00 0.27 1 2,186.07 0.27 18.00 0.27 1 2,186.07 0.27 19.00 0.27 1 2,186.07 0.27 20.00 0.27 1 2,186.07 0.27 21.00 0.26 0 2,186.07 0.26 22.00 0.25 0 2,186.07 0.25 23.00 0.25 0 2,186.07 0.25 24.00 0.24 0 2,186.07 0.24 25.00 0.22 0 2,186.07 0.22 26.00 0.19 0 2,186.06 0.19 27.00 0.16 0 2,186.06 0.16 28.00 0.11 0 2,186.05 0.11 29.00 0.07 0 2,186.04 0.07 30.00 0.04 0 2,186.03 0.04 31.00 0.03 0 2,186.03 0.03 32.00 0.02 0 2,186.02 0.02 33.00 0.02 0 2,186.02 0.02 34.00 0.01 0 2,186.02 0.01 35.00 0.01 0 2,186.02 0.01 36.00 0.01 0 2,186.01 0.01 37.00 0.01 0 2,186.01 0.01 38.00 0.01 0 2,186.01 0.01 39.00 0.00 0 2,186.01 0.00 40.00 0.00 0 2,186.01 0.00 41.00 0.00 0 2,186.01 0.00 42.00 0.00 0 2,186.00 0.00 43.00 0.00 0 2,186.00 0.00 44.00 0.00 0 2,186.00 0.00 45.00 0.00 0 2,186.00 0.00 46.00 0.00 0 2,186.00 0.00 47.00 0.00 0 2,186.00 0.00 48.00 0.00 0 2,186.00 0.00 L. Douglass - Ponderosa Ridge East - COSV Type II 24-hr 25 yr Rainfall=2.20"2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 18HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Summary for Pond 4P: Concept Pond for Sizing and Discharge Inflow Area = 13.260 ac, 38.00% Impervious, Inflow Depth = 0.48" for 25 yr event Inflow = 3.75 cfs @ 12.45 hrs, Volume= 0.534 af Outflow = 0.27 cfs @ 18.37 hrs, Volume= 0.308 af, Atten= 93%, Lag= 355.3 min Primary = 0.27 cfs @ 18.37 hrs, Volume= 0.308 af Routed to Reach 5R : Pipe to Infiltrators Routing by Stor-Ind method, Time Span= 1.00-48.00 hrs, dt= 0.05 hrs Peak Elev= 2,186.42' @ 18.37 hrs Surf.Area= 0.252 ac Storage= 0.328 af Plug-Flow detention time= 501.0 min calculated for 0.307 af (58% of inflow) Center-of-Mass det. time= 358.3 min ( 1,274.8 - 916.4 ) Volume Invert Avail.Storage Storage Description #1 2,185.00' 1.428 af 96.20'W x 96.20'L x 5.00'H Prismatoid Z=3.0 Device Routing Invert Outlet Devices #1 Primary 2,186.00'4.0" Horiz. Orifice/Grate C= 0.600 in 4.0" Grate (100% open area) Limited to weir flow at low heads Primary OutFlow Max=0.27 cfs @ 18.37 hrs HW=2,186.42' (Free Discharge) 1=Orifice/Grate (Orifice Controls 0.27 cfs @ 3.11 fps) Pond 4P: Concept Pond for Sizing and Discharge Inflow Primary Hydrograph Time (hours)48464442403836343230282624222018161412108642Flow (cfs)4 3 2 1 0 Inflow Area=13.260 ac Peak Elev=2,186.42' Storage=0.328 af 3.75 cfs 0.27 cfs L. Douglass - Ponderosa Ridge East - COSV Type II 24-hr 25 yr Rainfall=2.20"2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 19HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Pond 4P: Concept Pond for Sizing and Discharge Primary Stage-Discharge Discharge (cfs) 0.80.750.70.650.60.550.50.450.40.350.30.250.20.150.10.050Elevation (feet)2,190 2,189 2,188 2,187 2,186 2,185 Orifice/Grate Pond 4P: Concept Pond for Sizing and Discharge Storage Stage-Area-Storage Storage (acre-feet) 10Elevation (feet)2,190 2,189 2,188 2,187 2,186 2,185 Prismatoid L. Douglass - Ponderosa Ridge East - COSV Type II 24-hr 25 yr Rainfall=2.20"2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 20HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Hydrograph for Pond 4P: Concept Pond for Sizing and Discharge Time (hours) Inflow (cfs) Storage (acre-feet) Elevation (feet) Primary (cfs) 1.00 0.00 0.000 2,185.00 0.00 2.00 0.00 0.000 2,185.00 0.00 3.00 0.00 0.000 2,185.00 0.00 4.00 0.00 0.000 2,185.00 0.00 5.00 0.00 0.000 2,185.00 0.00 6.00 0.00 0.000 2,185.00 0.00 7.00 0.00 0.000 2,185.00 0.00 8.00 0.00 0.000 2,185.00 0.00 9.00 0.00 0.000 2,185.00 0.00 10.00 0.00 0.000 2,185.00 0.00 11.00 0.00 0.000 2,185.00 0.00 12.00 0.26 0.001 2,185.01 0.00 13.00 1.65 0.206 2,185.92 0.00 14.00 0.66 0.279 2,186.22 0.20 15.00 0.46 0.306 2,186.33 0.24 16.00 0.38 0.320 2,186.38 0.26 17.00 0.31 0.326 2,186.41 0.27 18.00 0.28 0.328 2,186.42 0.27 19.00 0.25 0.328 2,186.41 0.27 20.00 0.22 0.325 2,186.40 0.27 21.00 0.19 0.320 2,186.38 0.26 22.00 0.19 0.315 2,186.36 0.25 23.00 0.18 0.309 2,186.34 0.25 24.00 0.18 0.304 2,186.32 0.24 25.00 0.02 0.294 2,186.28 0.22 26.00 0.00 0.277 2,186.21 0.19 27.00 0.00 0.263 2,186.15 0.16 28.00 0.00 0.251 2,186.11 0.11 29.00 0.00 0.244 2,186.07 0.07 30.00 0.00 0.239 2,186.05 0.04 31.00 0.00 0.236 2,186.04 0.03 32.00 0.00 0.234 2,186.03 0.02 33.00 0.00 0.232 2,186.02 0.02 34.00 0.00 0.231 2,186.02 0.01 35.00 0.00 0.229 2,186.01 0.01 36.00 0.00 0.229 2,186.01 0.01 37.00 0.00 0.228 2,186.01 0.01 38.00 0.00 0.228 2,186.01 0.01 39.00 0.00 0.227 2,186.01 0.00 40.00 0.00 0.227 2,186.00 0.00 41.00 0.00 0.227 2,186.00 0.00 42.00 0.00 0.227 2,186.00 0.00 43.00 0.00 0.226 2,186.00 0.00 44.00 0.00 0.226 2,186.00 0.00 45.00 0.00 0.226 2,186.00 0.00 46.00 0.00 0.226 2,186.00 0.00 47.00 0.00 0.226 2,186.00 0.00 48.00 0.00 0.226 2,186.00 0.00 L. Douglass - Ponderosa Ridge East - COSV Type II 24-hr 25 yr Rainfall=2.20"2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 21HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Summary for Pond 6P: Infiltration Basin Inflow Area = 13.260 ac, 38.00% Impervious, Inflow Depth > 0.28" for 25 yr event Inflow = 0.27 cfs @ 18.36 hrs, Volume= 0.308 af Outflow = 0.27 cfs @ 18.38 hrs, Volume= 0.308 af, Atten= 0%, Lag= 1.7 min Discarded = 0.27 cfs @ 18.38 hrs, Volume= 0.308 af Routing by Stor-Ind method, Time Span= 1.00-48.00 hrs, dt= 0.05 hrs Peak Elev= 2,180.02' @ 18.38 hrs Surf.Area= 0.037 ac Storage= 0.000 af Plug-Flow detention time= 0.6 min calculated for 0.307 af (100% of inflow) Center-of-Mass det. time= 0.6 min ( 1,275.5 - 1,274.8 ) Volume Invert Avail.Storage Storage Description #1A 2,180.00' 0.034 af 34.75'W x 46.34'L x 3.50'H Field A 0.129 af Overall - 0.044 af Embedded = 0.085 af x 40.0% Voids #2A 2,180.50' 0.044 af ADS_StormTech SC-740 +Cap x 42 Inside #1 Effective Size= 44.6"W x 30.0"H => 6.45 sf x 7.12'L = 45.9 cf Overall Size= 51.0"W x 30.0"H x 7.56'L with 0.44' Overlap 42 Chambers in 7 Rows 0.078 af Total Available Storage Storage Group A created with Chamber Wizard Device Routing Invert Outlet Devices #1 Discarded 2,180.00'16.000 in/hr Exfiltration over Surface area Conductivity to Groundwater Elevation = 1,800.00' Discarded OutFlow Max=0.60 cfs @ 18.38 hrs HW=2,180.02' (Free Discharge) 1=Exfiltration ( Controls 0.60 cfs) L. Douglass - Ponderosa Ridge East - COSV Type II 24-hr 25 yr Rainfall=2.20"2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 22HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Pond 6P: Infiltration Basin - Chamber Wizard Field A Chamber Model = ADS_StormTech SC-740 +Cap (ADS StormTech® SC-740 with cap length) Effective Size= 44.6"W x 30.0"H => 6.45 sf x 7.12'L = 45.9 cf Overall Size= 51.0"W x 30.0"H x 7.56'L with 0.44' Overlap 51.0" Wide + 6.0" Spacing = 57.0" C-C Row Spacing 6 Chambers/Row x 7.12' Long +0.81' Cap Length x 2 = 44.34' Row Length +12.0" End Stone x 2 = 46.34' Base Length 7 Rows x 51.0" Wide + 6.0" Spacing x 6 + 12.0" Side Stone x 2 = 34.75' Base Width 6.0" Stone Base + 30.0" Chamber Height + 6.0" Stone Cover = 3.50' Field Height 42 Chambers x 45.9 cf = 1,929.5 cf Chamber Storage 5,635.7 cf Field - 1,929.5 cf Chambers = 3,706.2 cf Stone x 40.0% Voids = 1,482.5 cf Stone Storage Chamber Storage + Stone Storage = 3,412.0 cf = 0.078 af Overall Storage Efficiency = 60.5% Overall System Size = 46.34' x 34.75' x 3.50' 42 Chambers 208.7 cy Field 137.3 cy Stone L. Douglass - Ponderosa Ridge East - COSV Type II 24-hr 25 yr Rainfall=2.20"2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 23HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Pond 6P: Infiltration Basin Inflow Discarded Hydrograph Time (hours) 48464442403836343230282624222018161412108642Flow (cfs)0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Inflow Area=13.260 ac Peak Elev=2,180.02' Storage=0.000 af 0.27 cfs0.27 cfs Pond 6P: Infiltration Basin Discarded Stage-Discharge Discharge (cfs) 0.60.550.50.450.40.350.30.250.20.150.10.050Elevation (feet)2,183 2,182 2,181 2,180 Exfiltration L. Douglass - Ponderosa Ridge East - COSV Type II 24-hr 25 yr Rainfall=2.20"2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 24HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Pond 6P: Infiltration Basin Surface Storage Stage-Area-Storage Storage (acre-feet) 0.0750.070.0650.060.0550.050.0450.040.0350.030.0250.020.0150.010.0050 Surface/Horizontal/Wetted Area (acres)0.0360.0340.0320.030.0280.0260.0240.0220.020.0180.0160.0140.0120.010.0080.0060.0040.0020 Elevation (feet)2,183 2,182 2,181 2,180 Field A ADS_StormTech SC-740 +Cap L. Douglass - Ponderosa Ridge East - COSV Type II 24-hr 25 yr Rainfall=2.20"2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 25HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Hydrograph for Pond 6P: Infiltration Basin Time (hours) Inflow (cfs) Storage (acre-feet) Elevation (feet) Discarded (cfs) 1.00 0.00 0.000 2,180.00 0.00 2.00 0.00 0.000 2,180.00 0.00 3.00 0.00 0.000 2,180.00 0.00 4.00 0.00 0.000 2,180.00 0.00 5.00 0.00 0.000 2,180.00 0.00 6.00 0.00 0.000 2,180.00 0.00 7.00 0.00 0.000 2,180.00 0.00 8.00 0.00 0.000 2,180.00 0.00 9.00 0.00 0.000 2,180.00 0.00 10.00 0.00 0.000 2,180.00 0.00 11.00 0.00 0.000 2,180.00 0.00 12.00 0.00 0.000 2,180.00 0.00 13.00 0.00 0.000 2,180.00 0.00 14.00 0.20 0.000 2,180.01 0.20 15.00 0.24 0.000 2,180.01 0.24 16.00 0.26 0.000 2,180.02 0.26 17.00 0.27 0.000 2,180.02 0.27 18.00 0.27 0.000 2,180.02 0.27 19.00 0.27 0.000 2,180.02 0.27 20.00 0.27 0.000 2,180.02 0.27 21.00 0.26 0.000 2,180.02 0.26 22.00 0.25 0.000 2,180.01 0.25 23.00 0.25 0.000 2,180.01 0.25 24.00 0.24 0.000 2,180.01 0.24 25.00 0.22 0.000 2,180.01 0.22 26.00 0.19 0.000 2,180.01 0.19 27.00 0.16 0.000 2,180.01 0.16 28.00 0.11 0.000 2,180.01 0.11 29.00 0.07 0.000 2,180.00 0.07 30.00 0.04 0.000 2,180.00 0.04 31.00 0.03 0.000 2,180.00 0.03 32.00 0.02 0.000 2,180.00 0.02 33.00 0.02 0.000 2,180.00 0.02 34.00 0.01 0.000 2,180.00 0.01 35.00 0.01 0.000 2,180.00 0.01 36.00 0.01 0.000 2,180.00 0.01 37.00 0.01 0.000 2,180.00 0.01 38.00 0.01 0.000 2,180.00 0.01 39.00 0.00 0.000 2,180.00 0.00 40.00 0.00 0.000 2,180.00 0.00 41.00 0.00 0.000 2,180.00 0.00 42.00 0.00 0.000 2,180.00 0.00 43.00 0.00 0.000 2,180.00 0.00 44.00 0.00 0.000 2,180.00 0.00 45.00 0.00 0.000 2,180.00 0.00 46.00 0.00 0.000 2,180.00 0.00 47.00 0.00 0.000 2,180.00 0.00 48.00 0.00 0.000 2,180.00 0.00 L. Douglass - Ponderosa Ridge East - COSV Type II 24-hr 100 yr Rainfall=2.60"2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 26HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Time span=1.00-48.00 hrs, dt=0.05 hrs, 941 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=16.400 ac 0.00% Impervious Runoff Depth=0.34"Subcatchment 1S: 2798 Pre Dev Basin A Flow Length=1,370' Slope=0.1245 '/' Tc=232.7 min CN=65 Runoff=0.76 cfs 0.459 af Runoff Area=13.260 ac 38.00% Impervious Runoff Depth=0.71"Subcatchment 2S: 2798 Post Dev Basin A Flow Length=500' Tc=38.8 min CN=75 Runoff=6.02 cfs 0.784 af Avg. Flow Depth=0.48' Max Vel=16.33 fps Inflow=6.02 cfs 0.784 afReach 3R: Pipe System to Pond 12.0" Round Pipe n=0.010 L=1,040.0' S=0.0800 '/' Capacity=13.10 cfs Outflow=6.00 cfs 0.784 af Avg. Flow Depth=0.09' Max Vel=12.00 fps Inflow=0.41 cfs 0.558 afReach 5R: Pipe to Infiltrators 12.0" Round Pipe n=0.010 L=20.0' S=0.3000 '/' Capacity=25.37 cfs Outflow=0.41 cfs 0.558 af Peak Elev=2,186.95' Storage=0.467 af Inflow=6.00 cfs 0.784 afPond 4P: Concept Pond for Sizing and Outflow=0.41 cfs 0.558 af Peak Elev=2,180.02' Storage=0.000 af Inflow=0.41 cfs 0.558 afPond 6P: Infiltration Basin Outflow=0.41 cfs 0.558 af Total Runoff Area = 29.660 ac Runoff Volume = 1.243 af Average Runoff Depth = 0.50" 83.01% Pervious = 24.621 ac 16.99% Impervious = 5.039 ac L. Douglass - Ponderosa Ridge East - COSV Type II 24-hr 100 yr Rainfall=2.60"2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 27HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Summary for Subcatchment 1S: 2798 Pre Dev Basin A Runoff = 0.76 cfs @ 15.53 hrs, Volume= 0.459 af, Depth= 0.34" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 1.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr 100 yr Rainfall=2.60" Area (ac) CN Description 16.400 65 Woods/grass comb., Fair, HSG B 16.400 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 222.6 300 0.1245 0.02 Sheet Flow, Sheet Flow Woods: Light underbrush n= 0.400 P2= 0.04" 10.1 1,070 0.1245 1.76 Shallow Concentrated Flow, Shallow Concentrated Flow Woodland Kv= 5.0 fps 232.7 1,370 Total Subcatchment 1S: 2798 Pre Dev Basin A Runoff Hydrograph Time (hours) 48464442403836343230282624222018161412108642Flow (cfs)0.85 0.8 0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Type II 24-hr 100 yr Rainfall=2.60" Runoff Area=16.400 ac Runoff Volume=0.459 af Runoff Depth=0.34" Flow Length=1,370' Slope=0.1245 '/' Tc=232.7 min CN=65 0.76 cfs L. Douglass - Ponderosa Ridge East - COSV Type II 24-hr 100 yr Rainfall=2.60"2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 28HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Hydrograph for Subcatchment 1S: 2798 Pre Dev Basin A Time (hours) Precip. (inches) Excess (inches) Runoff (cfs) 1.00 0.03 0.00 0.00 1.50 0.04 0.00 0.00 2.00 0.06 0.00 0.00 2.50 0.07 0.00 0.00 3.00 0.09 0.00 0.00 3.50 0.11 0.00 0.00 4.00 0.12 0.00 0.00 4.50 0.14 0.00 0.00 5.00 0.16 0.00 0.00 5.50 0.19 0.00 0.00 6.00 0.21 0.00 0.00 6.50 0.23 0.00 0.00 7.00 0.26 0.00 0.00 7.50 0.28 0.00 0.00 8.00 0.31 0.00 0.00 8.50 0.34 0.00 0.00 9.00 0.38 0.00 0.00 9.50 0.42 0.00 0.00 10.00 0.47 0.00 0.00 10.50 0.53 0.00 0.00 11.00 0.61 0.00 0.00 11.50 0.74 0.00 0.00 12.00 1.72 0.07 0.00 12.50 1.91 0.11 0.02 13.00 2.01 0.14 0.09 13.50 2.08 0.16 0.23 14.00 2.13 0.17 0.43 14.50 2.18 0.19 0.61 15.00 2.22 0.20 0.72 15.50 2.26 0.21 0.76 16.00 2.29 0.22 0.74 16.50 2.32 0.23 0.68 17.00 2.34 0.24 0.61 17.50 2.37 0.25 0.55 18.00 2.39 0.26 0.50 18.50 2.42 0.27 0.46 19.00 2.44 0.27 0.42 19.50 2.46 0.28 0.39 20.00 2.48 0.29 0.36 20.50 2.49 0.29 0.33 21.00 2.51 0.30 0.31 21.50 2.52 0.31 0.29 22.00 2.54 0.31 0.27 22.50 2.56 0.32 0.26 23.00 2.57 0.32 0.24 23.50 2.59 0.33 0.23 24.00 2.60 0.34 0.22 24.50 2.60 0.34 0.21 25.00 2.60 0.34 0.21 25.50 2.60 0.34 0.19 26.00 2.60 0.34 0.17 26.50 2.60 0.34 0.14 Time (hours) Precip. (inches) Excess (inches) Runoff (cfs) 27.00 2.60 0.34 0.12 27.50 2.60 0.34 0.09 28.00 2.60 0.34 0.06 28.50 2.60 0.34 0.05 29.00 2.60 0.34 0.03 29.50 2.60 0.34 0.02 30.00 2.60 0.34 0.02 30.50 2.60 0.34 0.01 31.00 2.60 0.34 0.01 31.50 2.60 0.34 0.01 32.00 2.60 0.34 0.00 32.50 2.60 0.34 0.00 33.00 2.60 0.34 0.00 33.50 2.60 0.34 0.00 34.00 2.60 0.34 0.00 34.50 2.60 0.34 0.00 35.00 2.60 0.34 0.00 35.50 2.60 0.34 0.00 36.00 2.60 0.34 0.00 36.50 2.60 0.34 0.00 37.00 2.60 0.34 0.00 37.50 2.60 0.34 0.00 38.00 2.60 0.34 0.00 38.50 2.60 0.34 0.00 39.00 2.60 0.34 0.00 39.50 2.60 0.34 0.00 40.00 2.60 0.34 0.00 40.50 2.60 0.34 0.00 41.00 2.60 0.34 0.00 41.50 2.60 0.34 0.00 42.00 2.60 0.34 0.00 42.50 2.60 0.34 0.00 43.00 2.60 0.34 0.00 43.50 2.60 0.34 0.00 44.00 2.60 0.34 0.00 44.50 2.60 0.34 0.00 45.00 2.60 0.34 0.00 45.50 2.60 0.34 0.00 46.00 2.60 0.34 0.00 46.50 2.60 0.34 0.00 47.00 2.60 0.34 0.00 47.50 2.60 0.34 0.00 48.00 2.60 0.34 0.00 L. Douglass - Ponderosa Ridge East - COSV Type II 24-hr 100 yr Rainfall=2.60"2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 29HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Summary for Subcatchment 2S: 2798 Post Dev Basin A Runoff = 6.02 cfs @ 12.39 hrs, Volume= 0.784 af, Depth= 0.71" Routed to Reach 3R : Pipe System to Pond Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 1.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr 100 yr Rainfall=2.60" Area (ac) CN Description 13.260 75 1/4 acre lots, 38% imp, HSG B 8.221 62.00% Pervious Area 5.039 38.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 38.1 50 0.0400 0.02 Sheet Flow, Front Yards Grass: Short n= 0.150 P2= 0.04" 0.4 150 0.0800 5.74 Shallow Concentrated Flow, Gutter to Catch Basin Paved Kv= 20.3 fps 0.3 300 0.0800 16.68 13.10 Pipe Channel, Catch Basin to Pipe 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.010 PVC, smooth interior 38.8 500 Total Subcatchment 2S: 2798 Post Dev Basin A Runoff Hydrograph Time (hours) 48464442403836343230282624222018161412108642Flow (cfs)6 5 4 3 2 1 0 Type II 24-hr 100 yr Rainfall=2.60" Runoff Area=13.260 ac Runoff Volume=0.784 af Runoff Depth=0.71" Flow Length=500' Tc=38.8 min CN=75 6.02 cfs L. Douglass - Ponderosa Ridge East - COSV Type II 24-hr 100 yr Rainfall=2.60"2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 30HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Hydrograph for Subcatchment 2S: 2798 Post Dev Basin A Time (hours) Precip. (inches) Excess (inches) Runoff (cfs) 1.00 0.03 0.00 0.00 1.50 0.04 0.00 0.00 2.00 0.06 0.00 0.00 2.50 0.07 0.00 0.00 3.00 0.09 0.00 0.00 3.50 0.11 0.00 0.00 4.00 0.12 0.00 0.00 4.50 0.14 0.00 0.00 5.00 0.16 0.00 0.00 5.50 0.19 0.00 0.00 6.00 0.21 0.00 0.00 6.50 0.23 0.00 0.00 7.00 0.26 0.00 0.00 7.50 0.28 0.00 0.00 8.00 0.31 0.00 0.00 8.50 0.34 0.00 0.00 9.00 0.38 0.00 0.00 9.50 0.42 0.00 0.00 10.00 0.47 0.00 0.00 10.50 0.53 0.00 0.00 11.00 0.61 0.00 0.00 11.50 0.74 0.00 0.00 12.00 1.72 0.25 1.09 12.50 1.91 0.34 5.62 13.00 2.01 0.38 2.28 13.50 2.08 0.42 1.26 14.00 2.13 0.45 0.90 14.50 2.18 0.47 0.71 15.00 2.22 0.49 0.63 15.50 2.26 0.51 0.57 16.00 2.29 0.53 0.51 16.50 2.32 0.55 0.45 17.00 2.34 0.56 0.42 17.50 2.37 0.58 0.40 18.00 2.39 0.59 0.38 18.50 2.42 0.60 0.36 19.00 2.44 0.61 0.34 19.50 2.46 0.63 0.31 20.00 2.48 0.64 0.29 20.50 2.49 0.65 0.27 21.00 2.51 0.66 0.26 21.50 2.52 0.66 0.26 22.00 2.54 0.67 0.25 22.50 2.56 0.68 0.25 23.00 2.57 0.69 0.24 23.50 2.59 0.70 0.24 24.00 2.60 0.71 0.23 24.50 2.60 0.71 0.13 25.00 2.60 0.71 0.02 25.50 2.60 0.71 0.00 26.00 2.60 0.71 0.00 26.50 2.60 0.71 0.00 Time (hours) Precip. (inches) Excess (inches) Runoff (cfs) 27.00 2.60 0.71 0.00 27.50 2.60 0.71 0.00 28.00 2.60 0.71 0.00 28.50 2.60 0.71 0.00 29.00 2.60 0.71 0.00 29.50 2.60 0.71 0.00 30.00 2.60 0.71 0.00 30.50 2.60 0.71 0.00 31.00 2.60 0.71 0.00 31.50 2.60 0.71 0.00 32.00 2.60 0.71 0.00 32.50 2.60 0.71 0.00 33.00 2.60 0.71 0.00 33.50 2.60 0.71 0.00 34.00 2.60 0.71 0.00 34.50 2.60 0.71 0.00 35.00 2.60 0.71 0.00 35.50 2.60 0.71 0.00 36.00 2.60 0.71 0.00 36.50 2.60 0.71 0.00 37.00 2.60 0.71 0.00 37.50 2.60 0.71 0.00 38.00 2.60 0.71 0.00 38.50 2.60 0.71 0.00 39.00 2.60 0.71 0.00 39.50 2.60 0.71 0.00 40.00 2.60 0.71 0.00 40.50 2.60 0.71 0.00 41.00 2.60 0.71 0.00 41.50 2.60 0.71 0.00 42.00 2.60 0.71 0.00 42.50 2.60 0.71 0.00 43.00 2.60 0.71 0.00 43.50 2.60 0.71 0.00 44.00 2.60 0.71 0.00 44.50 2.60 0.71 0.00 45.00 2.60 0.71 0.00 45.50 2.60 0.71 0.00 46.00 2.60 0.71 0.00 46.50 2.60 0.71 0.00 47.00 2.60 0.71 0.00 47.50 2.60 0.71 0.00 48.00 2.60 0.71 0.00 L. Douglass - Ponderosa Ridge East - COSV Type II 24-hr 100 yr Rainfall=2.60"2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 31HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Summary for Reach 3R: Pipe System to Pond Inflow Area = 13.260 ac, 38.00% Impervious, Inflow Depth = 0.71" for 100 yr event Inflow = 6.02 cfs @ 12.39 hrs, Volume= 0.784 af Outflow = 6.00 cfs @ 12.42 hrs, Volume= 0.784 af, Atten= 0%, Lag= 1.9 min Routed to Pond 4P : Concept Pond for Sizing and Discharge Routing by Stor-Ind+Trans method, Time Span= 1.00-48.00 hrs, dt= 0.05 hrs Max. Velocity= 16.33 fps, Min. Travel Time= 1.1 min Avg. Velocity = 7.27 fps, Avg. Travel Time= 2.4 min Peak Storage= 383 cf @ 12.41 hrs Average Depth at Peak Storage= 0.48' , Surface Width= 1.00' Bank-Full Depth= 1.00' Flow Area= 0.8 sf, Capacity= 13.10 cfs 12.0" Round Pipe n= 0.010 PVC, smooth interior Length= 1,040.0' Slope= 0.0800 '/' Inlet Invert= 2,270.00', Outlet Invert= 2,186.80' Reach 3R: Pipe System to Pond InflowOutflow Hydrograph Time (hours) 48464442403836343230282624222018161412108642Flow (cfs)6 5 4 3 2 1 0 Inflow Area=13.260 ac Avg. Flow Depth=0.48' Max Vel=16.33 fps 12.0" Round Pipe n=0.010 L=1,040.0' S=0.0800 '/' Capacity=13.10 cfs 6.02 cfs6.00 cfs L. Douglass - Ponderosa Ridge East - COSV Type II 24-hr 100 yr Rainfall=2.60"2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 32HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Reach 3R: Pipe System to Pond Primary Stage-Discharge Discharge (cfs) 14131211109876543210Depth (feet)1 0 Reach 3R: Pipe System to Pond Storage Stage-Storage Storage (cubic-feet) 8007006005004003002001000Depth (feet)1 0 L. Douglass - Ponderosa Ridge East - COSV Type II 24-hr 100 yr Rainfall=2.60"2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 33HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Hydrograph for Reach 3R: Pipe System to Pond Time (hours) Inflow (cfs) Storage (cubic-feet) Elevation (feet) Outflow (cfs) 1.00 0.00 0 2,270.00 0.00 2.00 0.00 0 2,270.00 0.00 3.00 0.00 0 2,270.00 0.00 4.00 0.00 0 2,270.00 0.00 5.00 0.00 0 2,270.00 0.00 6.00 0.00 0 2,270.00 0.00 7.00 0.00 0 2,270.00 0.00 8.00 0.00 0 2,270.00 0.00 9.00 0.00 0 2,270.00 0.00 10.00 0.00 0 2,270.00 0.00 11.00 0.00 0 2,270.00 0.00 12.00 1.09 97 2,270.18 0.75 13.00 2.28 193 2,270.29 2.41 14.00 0.90 99 2,270.18 0.92 15.00 0.63 76 2,270.15 0.63 16.00 0.51 66 2,270.14 0.52 17.00 0.42 58 2,270.12 0.43 18.00 0.38 54 2,270.12 0.38 19.00 0.34 49 2,270.11 0.34 20.00 0.29 44 2,270.10 0.29 21.00 0.26 41 2,270.10 0.26 22.00 0.25 40 2,270.10 0.25 23.00 0.24 39 2,270.09 0.24 24.00 0.23 38 2,270.09 0.23 25.00 0.02 8 2,270.03 0.03 26.00 0.00 1 2,270.00 0.00 27.00 0.00 0 2,270.00 0.00 28.00 0.00 0 2,270.00 0.00 29.00 0.00 0 2,270.00 0.00 30.00 0.00 0 2,270.00 0.00 31.00 0.00 0 2,270.00 0.00 32.00 0.00 0 2,270.00 0.00 33.00 0.00 0 2,270.00 0.00 34.00 0.00 0 2,270.00 0.00 35.00 0.00 0 2,270.00 0.00 36.00 0.00 0 2,270.00 0.00 37.00 0.00 0 2,270.00 0.00 38.00 0.00 0 2,270.00 0.00 39.00 0.00 0 2,270.00 0.00 40.00 0.00 0 2,270.00 0.00 41.00 0.00 0 2,270.00 0.00 42.00 0.00 0 2,270.00 0.00 43.00 0.00 0 2,270.00 0.00 44.00 0.00 0 2,270.00 0.00 45.00 0.00 0 2,270.00 0.00 46.00 0.00 0 2,270.00 0.00 47.00 0.00 0 2,270.00 0.00 48.00 0.00 0 2,270.00 0.00 L. Douglass - Ponderosa Ridge East - COSV Type II 24-hr 100 yr Rainfall=2.60"2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 34HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Summary for Reach 5R: Pipe to Infiltrators Inflow Area = 13.260 ac, 38.00% Impervious, Inflow Depth > 0.50" for 100 yr event Inflow = 0.41 cfs @ 17.36 hrs, Volume= 0.558 af Outflow = 0.41 cfs @ 17.35 hrs, Volume= 0.558 af, Atten= 0%, Lag= 0.0 min Routed to Pond 6P : Infiltration Basin Routing by Stor-Ind+Trans method, Time Span= 1.00-48.00 hrs, dt= 0.05 hrs Max. Velocity= 12.00 fps, Min. Travel Time= 0.0 min Avg. Velocity = 8.08 fps, Avg. Travel Time= 0.0 min Peak Storage= 1 cf @ 17.35 hrs Average Depth at Peak Storage= 0.09' , Surface Width= 0.57' Bank-Full Depth= 1.00' Flow Area= 0.8 sf, Capacity= 25.37 cfs 12.0" Round Pipe n= 0.010 PVC, smooth interior Length= 20.0' Slope= 0.3000 '/' Inlet Invert= 2,186.00', Outlet Invert= 2,180.00' Reach 5R: Pipe to Infiltrators InflowOutflow Hydrograph Time (hours) 48464442403836343230282624222018161412108642Flow (cfs)0.44 0.42 0.4 0.38 0.36 0.34 0.32 0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Inflow Area=13.260 ac Avg. Flow Depth=0.09' Max Vel=12.00 fps 12.0" Round Pipe n=0.010 L=20.0' S=0.3000 '/' Capacity=25.37 cfs 0.41 cfs0.41 cfs L. Douglass - Ponderosa Ridge East - COSV Type II 24-hr 100 yr Rainfall=2.60"2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 35HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Reach 5R: Pipe to Infiltrators Primary Stage-Discharge Discharge (cfs) 26242220181614121086420Depth (feet)1 0 Reach 5R: Pipe to Infiltrators Storage Stage-Storage Storage (cubic-feet) 1514131211109876543210Depth (feet)1 0 L. Douglass - Ponderosa Ridge East - COSV Type II 24-hr 100 yr Rainfall=2.60"2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 36HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Hydrograph for Reach 5R: Pipe to Infiltrators Time (hours) Inflow (cfs) Storage (cubic-feet) Elevation (feet) Outflow (cfs) 1.00 0.00 0 2,186.00 0.00 2.00 0.00 0 2,186.00 0.00 3.00 0.00 0 2,186.00 0.00 4.00 0.00 0 2,186.00 0.00 5.00 0.00 0 2,186.00 0.00 6.00 0.00 0 2,186.00 0.00 7.00 0.00 0 2,186.00 0.00 8.00 0.00 0 2,186.00 0.00 9.00 0.00 0 2,186.00 0.00 10.00 0.00 0 2,186.00 0.00 11.00 0.00 0 2,186.00 0.00 12.00 0.00 0 2,186.00 0.00 13.00 0.27 1 2,186.07 0.27 14.00 0.37 1 2,186.08 0.37 15.00 0.39 1 2,186.09 0.39 16.00 0.41 1 2,186.09 0.41 17.00 0.41 1 2,186.09 0.41 18.00 0.41 1 2,186.09 0.41 19.00 0.41 1 2,186.09 0.41 20.00 0.40 1 2,186.09 0.40 21.00 0.39 1 2,186.09 0.39 22.00 0.38 1 2,186.09 0.38 23.00 0.37 1 2,186.08 0.37 24.00 0.36 1 2,186.08 0.36 25.00 0.35 1 2,186.08 0.35 26.00 0.32 1 2,186.08 0.32 27.00 0.29 1 2,186.07 0.29 28.00 0.26 0 2,186.07 0.26 29.00 0.23 0 2,186.07 0.23 30.00 0.20 0 2,186.06 0.20 31.00 0.17 0 2,186.06 0.17 32.00 0.13 0 2,186.05 0.13 33.00 0.08 0 2,186.04 0.08 34.00 0.05 0 2,186.03 0.05 35.00 0.03 0 2,186.03 0.03 36.00 0.03 0 2,186.02 0.03 37.00 0.02 0 2,186.02 0.02 38.00 0.02 0 2,186.02 0.02 39.00 0.01 0 2,186.02 0.01 40.00 0.01 0 2,186.01 0.01 41.00 0.01 0 2,186.01 0.01 42.00 0.01 0 2,186.01 0.01 43.00 0.00 0 2,186.01 0.00 44.00 0.00 0 2,186.01 0.00 45.00 0.00 0 2,186.01 0.00 46.00 0.00 0 2,186.00 0.00 47.00 0.00 0 2,186.00 0.00 48.00 0.00 0 2,186.00 0.00 L. Douglass - Ponderosa Ridge East - COSV Type II 24-hr 100 yr Rainfall=2.60"2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 37HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Summary for Pond 4P: Concept Pond for Sizing and Discharge Inflow Area = 13.260 ac, 38.00% Impervious, Inflow Depth = 0.71" for 100 yr event Inflow = 6.00 cfs @ 12.42 hrs, Volume= 0.784 af Outflow = 0.41 cfs @ 17.36 hrs, Volume= 0.558 af, Atten= 93%, Lag= 295.9 min Primary = 0.41 cfs @ 17.36 hrs, Volume= 0.558 af Routed to Reach 5R : Pipe to Infiltrators Routing by Stor-Ind method, Time Span= 1.00-48.00 hrs, dt= 0.05 hrs Peak Elev= 2,186.95' @ 17.36 hrs Surf.Area= 0.267 ac Storage= 0.467 af Plug-Flow detention time= 531.9 min calculated for 0.558 af (71% of inflow) Center-of-Mass det. time= 418.4 min ( 1,320.9 - 902.5 ) Volume Invert Avail.Storage Storage Description #1 2,185.00' 1.428 af 96.20'W x 96.20'L x 5.00'H Prismatoid Z=3.0 Device Routing Invert Outlet Devices #1 Primary 2,186.00'4.0" Horiz. Orifice/Grate C= 0.600 in 4.0" Grate (100% open area) Limited to weir flow at low heads Primary OutFlow Max=0.41 cfs @ 17.36 hrs HW=2,186.95' (Free Discharge) 1=Orifice/Grate (Orifice Controls 0.41 cfs @ 4.69 fps) Pond 4P: Concept Pond for Sizing and Discharge Inflow Primary Hydrograph Time (hours)48464442403836343230282624222018161412108642Flow (cfs)6 5 4 3 2 1 0 Inflow Area=13.260 ac Peak Elev=2,186.95' Storage=0.467 af 6.00 cfs 0.41 cfs L. Douglass - Ponderosa Ridge East - COSV Type II 24-hr 100 yr Rainfall=2.60"2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 38HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Pond 4P: Concept Pond for Sizing and Discharge Primary Stage-Discharge Discharge (cfs) 0.80.750.70.650.60.550.50.450.40.350.30.250.20.150.10.050Elevation (feet)2,190 2,189 2,188 2,187 2,186 2,185 Orifice/Grate Pond 4P: Concept Pond for Sizing and Discharge Storage Stage-Area-Storage Storage (acre-feet) 10Elevation (feet)2,190 2,189 2,188 2,187 2,186 2,185 Prismatoid L. Douglass - Ponderosa Ridge East - COSV Type II 24-hr 100 yr Rainfall=2.60"2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 39HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Hydrograph for Pond 4P: Concept Pond for Sizing and Discharge Time (hours) Inflow (cfs) Storage (acre-feet) Elevation (feet) Primary (cfs) 1.00 0.00 0.000 2,185.00 0.00 2.00 0.00 0.000 2,185.00 0.00 3.00 0.00 0.000 2,185.00 0.00 4.00 0.00 0.000 2,185.00 0.00 5.00 0.00 0.000 2,185.00 0.00 6.00 0.00 0.000 2,185.00 0.00 7.00 0.00 0.000 2,185.00 0.00 8.00 0.00 0.000 2,185.00 0.00 9.00 0.00 0.000 2,185.00 0.00 10.00 0.00 0.000 2,185.00 0.00 11.00 0.00 0.000 2,185.00 0.00 12.00 0.75 0.005 2,185.02 0.00 13.00 2.41 0.328 2,186.42 0.27 14.00 0.92 0.418 2,186.77 0.37 15.00 0.63 0.448 2,186.88 0.39 16.00 0.52 0.462 2,186.93 0.41 17.00 0.43 0.467 2,186.95 0.41 18.00 0.38 0.466 2,186.95 0.41 19.00 0.34 0.462 2,186.93 0.41 20.00 0.29 0.455 2,186.91 0.40 21.00 0.26 0.445 2,186.87 0.39 22.00 0.25 0.434 2,186.83 0.38 23.00 0.24 0.423 2,186.79 0.37 24.00 0.23 0.413 2,186.75 0.36 25.00 0.03 0.395 2,186.68 0.35 26.00 0.00 0.368 2,186.57 0.32 27.00 0.00 0.343 2,186.48 0.29 28.00 0.00 0.321 2,186.39 0.26 29.00 0.00 0.300 2,186.30 0.23 30.00 0.00 0.282 2,186.23 0.20 31.00 0.00 0.267 2,186.17 0.17 32.00 0.00 0.254 2,186.12 0.13 33.00 0.00 0.246 2,186.08 0.08 34.00 0.00 0.240 2,186.06 0.05 35.00 0.00 0.237 2,186.05 0.03 36.00 0.00 0.234 2,186.03 0.03 37.00 0.00 0.232 2,186.03 0.02 38.00 0.00 0.231 2,186.02 0.02 39.00 0.00 0.230 2,186.02 0.01 40.00 0.00 0.229 2,186.01 0.01 41.00 0.00 0.228 2,186.01 0.01 42.00 0.00 0.228 2,186.01 0.01 43.00 0.00 0.227 2,186.01 0.00 44.00 0.00 0.227 2,186.00 0.00 45.00 0.00 0.227 2,186.00 0.00 46.00 0.00 0.227 2,186.00 0.00 47.00 0.00 0.226 2,186.00 0.00 48.00 0.00 0.226 2,186.00 0.00 L. Douglass - Ponderosa Ridge East - COSV Type II 24-hr 100 yr Rainfall=2.60"2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 40HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Summary for Pond 6P: Infiltration Basin Inflow Area = 13.260 ac, 38.00% Impervious, Inflow Depth > 0.50" for 100 yr event Inflow = 0.41 cfs @ 17.35 hrs, Volume= 0.558 af Outflow = 0.41 cfs @ 17.37 hrs, Volume= 0.558 af, Atten= 0%, Lag= 1.1 min Discarded = 0.41 cfs @ 17.37 hrs, Volume= 0.558 af Routing by Stor-Ind method, Time Span= 1.00-48.00 hrs, dt= 0.05 hrs Peak Elev= 2,180.02' @ 17.37 hrs Surf.Area= 0.037 ac Storage= 0.000 af Plug-Flow detention time= 0.6 min calculated for 0.558 af (100% of inflow) Center-of-Mass det. time= 0.6 min ( 1,321.6 - 1,321.0 ) Volume Invert Avail.Storage Storage Description #1A 2,180.00' 0.034 af 34.75'W x 46.34'L x 3.50'H Field A 0.129 af Overall - 0.044 af Embedded = 0.085 af x 40.0% Voids #2A 2,180.50' 0.044 af ADS_StormTech SC-740 +Cap x 42 Inside #1 Effective Size= 44.6"W x 30.0"H => 6.45 sf x 7.12'L = 45.9 cf Overall Size= 51.0"W x 30.0"H x 7.56'L with 0.44' Overlap 42 Chambers in 7 Rows 0.078 af Total Available Storage Storage Group A created with Chamber Wizard Device Routing Invert Outlet Devices #1 Discarded 2,180.00'16.000 in/hr Exfiltration over Surface area Conductivity to Groundwater Elevation = 1,800.00' Discarded OutFlow Max=0.60 cfs @ 17.37 hrs HW=2,180.02' (Free Discharge) 1=Exfiltration ( Controls 0.60 cfs) L. Douglass - Ponderosa Ridge East - COSV Type II 24-hr 100 yr Rainfall=2.60"2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 41HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Pond 6P: Infiltration Basin - Chamber Wizard Field A Chamber Model = ADS_StormTech SC-740 +Cap (ADS StormTech® SC-740 with cap length) Effective Size= 44.6"W x 30.0"H => 6.45 sf x 7.12'L = 45.9 cf Overall Size= 51.0"W x 30.0"H x 7.56'L with 0.44' Overlap 51.0" Wide + 6.0" Spacing = 57.0" C-C Row Spacing 6 Chambers/Row x 7.12' Long +0.81' Cap Length x 2 = 44.34' Row Length +12.0" End Stone x 2 = 46.34' Base Length 7 Rows x 51.0" Wide + 6.0" Spacing x 6 + 12.0" Side Stone x 2 = 34.75' Base Width 6.0" Stone Base + 30.0" Chamber Height + 6.0" Stone Cover = 3.50' Field Height 42 Chambers x 45.9 cf = 1,929.5 cf Chamber Storage 5,635.7 cf Field - 1,929.5 cf Chambers = 3,706.2 cf Stone x 40.0% Voids = 1,482.5 cf Stone Storage Chamber Storage + Stone Storage = 3,412.0 cf = 0.078 af Overall Storage Efficiency = 60.5% Overall System Size = 46.34' x 34.75' x 3.50' 42 Chambers 208.7 cy Field 137.3 cy Stone L. Douglass - Ponderosa Ridge East - COSV Type II 24-hr 100 yr Rainfall=2.60"2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 42HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Pond 6P: Infiltration Basin Inflow Discarded Hydrograph Time (hours) 48464442403836343230282624222018161412108642Flow (cfs)0.44 0.42 0.4 0.38 0.36 0.34 0.32 0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Inflow Area=13.260 ac Peak Elev=2,180.02' Storage=0.000 af 0.41 cfs0.41 cfs Pond 6P: Infiltration Basin Discarded Stage-Discharge Discharge (cfs) 0.60.550.50.450.40.350.30.250.20.150.10.050Elevation (feet)2,183 2,182 2,181 2,180 Exfiltration L. Douglass - Ponderosa Ridge East - COSV Type II 24-hr 100 yr Rainfall=2.60"2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 43HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Pond 6P: Infiltration Basin Surface Storage Stage-Area-Storage Storage (acre-feet) 0.0750.070.0650.060.0550.050.0450.040.0350.030.0250.020.0150.010.0050 Surface/Horizontal/Wetted Area (acres)0.0360.0340.0320.030.0280.0260.0240.0220.020.0180.0160.0140.0120.010.0080.0060.0040.0020 Elevation (feet)2,183 2,182 2,181 2,180 Field A ADS_StormTech SC-740 +Cap L. Douglass - Ponderosa Ridge East - COSV Type II 24-hr 100 yr Rainfall=2.60"2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 44HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Hydrograph for Pond 6P: Infiltration Basin Time (hours) Inflow (cfs) Storage (acre-feet) Elevation (feet) Discarded (cfs) 1.00 0.00 0.000 2,180.00 0.00 2.00 0.00 0.000 2,180.00 0.00 3.00 0.00 0.000 2,180.00 0.00 4.00 0.00 0.000 2,180.00 0.00 5.00 0.00 0.000 2,180.00 0.00 6.00 0.00 0.000 2,180.00 0.00 7.00 0.00 0.000 2,180.00 0.00 8.00 0.00 0.000 2,180.00 0.00 9.00 0.00 0.000 2,180.00 0.00 10.00 0.00 0.000 2,180.00 0.00 11.00 0.00 0.000 2,180.00 0.00 12.00 0.00 0.000 2,180.00 0.00 13.00 0.27 0.000 2,180.02 0.27 14.00 0.37 0.000 2,180.02 0.37 15.00 0.39 0.000 2,180.02 0.39 16.00 0.41 0.000 2,180.02 0.41 17.00 0.41 0.000 2,180.02 0.41 18.00 0.41 0.000 2,180.02 0.41 19.00 0.41 0.000 2,180.02 0.41 20.00 0.40 0.000 2,180.02 0.40 21.00 0.39 0.000 2,180.02 0.39 22.00 0.38 0.000 2,180.02 0.38 23.00 0.37 0.000 2,180.02 0.37 24.00 0.36 0.000 2,180.02 0.36 25.00 0.35 0.000 2,180.02 0.35 26.00 0.32 0.000 2,180.02 0.32 27.00 0.29 0.000 2,180.02 0.29 28.00 0.26 0.000 2,180.02 0.26 29.00 0.23 0.000 2,180.01 0.23 30.00 0.20 0.000 2,180.01 0.20 31.00 0.17 0.000 2,180.01 0.17 32.00 0.13 0.000 2,180.01 0.13 33.00 0.08 0.000 2,180.00 0.08 34.00 0.05 0.000 2,180.00 0.05 35.00 0.03 0.000 2,180.00 0.03 36.00 0.03 0.000 2,180.00 0.03 37.00 0.02 0.000 2,180.00 0.02 38.00 0.02 0.000 2,180.00 0.02 39.00 0.01 0.000 2,180.00 0.01 40.00 0.01 0.000 2,180.00 0.01 41.00 0.01 0.000 2,180.00 0.01 42.00 0.01 0.000 2,180.00 0.01 43.00 0.00 0.000 2,180.00 0.00 44.00 0.00 0.000 2,180.00 0.00 45.00 0.00 0.000 2,180.00 0.00 46.00 0.00 0.000 2,180.00 0.00 47.00 0.00 0.000 2,180.00 0.00 48.00 0.00 0.000 2,180.00 0.00 L. Douglass - Ponderosa Ridge East - COSV Multi-Event Tables2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 45HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Events for Subcatchment 1S: 2798 Pre Dev Basin A Event Rainfall (inches) Runoff (cfs) Volume (acre-feet) Depth (inches) 25 yr 2.20 0.40 0.265 0.19 100 yr 2.60 0.76 0.459 0.34 L. Douglass - Ponderosa Ridge East - COSV Multi-Event Tables2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 46HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Events for Subcatchment 2S: 2798 Post Dev Basin A Event Rainfall (inches) Runoff (cfs) Volume (acre-feet) Depth (inches) 25 yr 2.20 3.77 0.534 0.48 100 yr 2.60 6.02 0.784 0.71 L. Douglass - Ponderosa Ridge East - COSV Multi-Event Tables2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 47HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Events for Reach 3R: Pipe System to Pond Event Inflow (cfs) Outflow (cfs) Elevation (feet) Storage (cubic-feet) 25 yr 3.77 3.75 2,270.37 272 100 yr 6.02 6.00 2,270.48 383 L. Douglass - Ponderosa Ridge East - COSV Multi-Event Tables2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 48HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Events for Reach 5R: Pipe to Infiltrators Event Inflow (cfs) Outflow (cfs) Elevation (feet) Storage (cubic-feet) 25 yr 0.27 0.27 2,186.07 1 100 yr 0.41 0.41 2,186.09 1 L. Douglass - Ponderosa Ridge East - COSV Multi-Event Tables2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 49HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Events for Pond 4P: Concept Pond for Sizing and Discharge Event Inflow (cfs) Primary (cfs) Elevation (feet) Storage (acre-feet) 25 yr 3.75 0.27 2,186.42 0.328 100 yr 6.00 0.41 2,186.95 0.467 L. Douglass - Ponderosa Ridge East - COSV Multi-Event Tables2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers Page 50HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC Events for Pond 6P: Infiltration Basin Event Inflow (cfs) Discarded (cfs) Elevation (feet) Storage (acre-feet) 25 yr 0.27 0.27 2,180.02 0.000 100 yr 0.41 0.41 2,180.02 0.000 L. Douglass - Ponderosa Ridge East - COSV Table of Contents2798 - Concept Storm Printed 1/3/2023Prepared by Whipple Consulting Engineers HydroCAD® 10.20-2f s/n 10129 © 2022 HydroCAD Software Solutions LLC TABLE OF CONTENTS Project Reports 1 Routing Diagram 2 Rainfall Events Listing (selected events) 3 Area Listing (all nodes) 4 Soil Listing (all nodes) 5 Ground Covers (all nodes) 6 Pipe Listing (all nodes) 25 yr Event 7 Node Listing 8 Subcat 1S: 2798 Pre Dev Basin A 10 Subcat 2S: 2798 Post Dev Basin A 12 Reach 3R: Pipe System to Pond 15 Reach 5R: Pipe to Infiltrators 18 Pond 4P: Concept Pond for Sizing and Discharge 21 Pond 6P: Infiltration Basin 100 yr Event 26 Node Listing 27 Subcat 1S: 2798 Pre Dev Basin A 29 Subcat 2S: 2798 Post Dev Basin A 31 Reach 3R: Pipe System to Pond 34 Reach 5R: Pipe to Infiltrators 37 Pond 4P: Concept Pond for Sizing and Discharge 40 Pond 6P: Infiltration Basin Multi-Event Tables 45 Subcat 1S: 2798 Pre Dev Basin A 46 Subcat 2S: 2798 Post Dev Basin A 47 Reach 3R: Pipe System to Pond 48 Reach 5R: Pipe to Infiltrators 49 Pond 4P: Concept Pond for Sizing and Discharge 50 Pond 6P: Infiltration Basin ~il ~ gwwv1t:rH1~ 'l-' ...... t()(J '1fl .. ~wl -eAr,6NAL &IA y;r12 u1~ IA.I I ?TlJ~E"tlt &#M1J1£e'7 Arc~~ Whipple Consulting Engineers Basin Calculation Worksheet 12/22/2022 TRW WCENo. 20-2798 Project Name Pondersoa COSY Imp Per 0.9 0.15 SPOKANE COUNTY -SRSM-GRASSED PERCOLATION METHOD Basin Total Access/Parking Sidewalk Adi.SW Buildings sf /Street (st) sf sf sf PREA 714,593 0 0 0 0 Pre Total 714,593 0 0 0 0 Post Onsite Flow i Post Basin A 574,925 102,211 2,820 0 175,500 Post Basin B 61,556 16,399 2,178 0 10,500 Post Basin C 78,112 16,399 2,178 0 16,500 TOTAL 714,593 135,009 7,176 0 202,500 I Intensities from SRSM eqn. 5-13, per Table 5-7, Assumes Tc= 5 min I (2 yr)= 1.418 inches I (IO yr)= 2.619 inches NOTE: I (25 yr)= 3.319 inches I (50 yr)= 3.843 inches I(lOOyr)= 4.381 inches 1133 A Q=CIA (cfs) Total Total Weighted PGIS Pond Pond 2 yr LO yr 25 yr 50 yr JOO yr Impervious Pervious "C" sf Area (st) Vol (ct) 0.00 714,593.00 0.15 0.00 0 0 3.49 6.44 8.17 9.46 10.78 0.00 714,593.00 0.15 0.00 0 0 3.49 6.44 8.17 9.46 10.78 . I i 280,530.92 294,394.08 0.52 102,210.92 5,317 2,659 9.66 17.83 22.60 26.17 29.83 29,077.04 32,478.96 0.50 16,399.04 853 427 1.01 1.87 2.37 2.74 3.12 35,077.04 43,034.96 0.49 16,399.04 853 427 1.24 2.29 2.90 3.35 3.82 344,685 369,908 0.51 135,009.00 7,023 3,512 11.90 21.99 27.86 32.26 36.78 PEAK FLOW CALCULATION PROJECT: BOWSTRING METHOD PROJECT: Ponderosa COSV Rainfall Intensity Coefficients for Spokane 100-Year Design Storm Ponderosa COSV DETENTION BASIN BASIN: B taken from Table 5-7 SRSM Flow (weighted c) 20-2798 DESIGN DESIGNER: trw M,oo = 12.33 Qwc= 3.12 els BASIN: B DA TE: 3-Jan-23 N100 = 0.643 Flow (time of concentration) Qtc= 3.12 els Tot. Area 61,556 SF 1.41 Acres Time Increment (min) 10 Imp. Area 29,077 SF C= 0.9 Time of Cone. (min) 5.00 Perv. Area 32,479 SF C= 0.15 Outflow (els) 0.3809 Time Time Inc. lntens. Q Devel Vol.In Vol.Out Storage Wt.C= 0.50 PGIS Area= 16,399 Design Year Flow 100 (min) (sec) (in/hr) (els) (cu ft) (cu ft) (cu ft) Area (acres) 1.41 385 WCE Applicable Travel Time Ground Cover Coefficients Impervious Area (sq ft) 29,077 395 23700 0.26 0.1877 4466 9028 -4562 Per Table 5-6 SRSM 'C' Factor 0.50 405 24300 0.25 0.1805 4405 9257 -4851 Tyge of Cover K (ft/min) Area• C 0.713 415 24900 0.25 0.1805 4514 9485 -4972 Short Pasture 420 PGJS Area 16,399 425 25500 0.24 0.1734 4439 9714 -5274 Nearly Bare Ground 600 435 26100 0.24 0.1734 4543 9942 -5399 Small Roadside Ditch/ Grass 900 Time Time Inc. lntens. Q Devel. Vol.In Vol.Out Storage 445 26700 0.23 0.1663 4456 10171 -5714 Paved Area (use for parking lots) 1200 (min) (sec) (in/hr) (els) (cu ft) (cu ft) (cu ft) 455 27300 0.23 0.1663 4556 10399 -5843 Gutter - 4 inches deep 1500 5.00 300 4.38 3.12 1255 114 1141 465 27900 0.22 0.1591 4456 10628 -6171 Gutter - 6 inches deep 2400 475 28500 0.22 0.1591 4552 10856 -6305 Pipe -12-inch PVC/DI 3000 15 900 2.16 1.54 1543 343 1200 485 29100 0.21 0.152 4439 11085 -6646 Pipe-15/18-inch PVC/DI 3900 25 1500 1.56 1.11 1777 571 1205 <==I I 495 29700 0.21 0.152 4531 11314 -6783 Pipe -24-inch PVC/DI 4700 35 2100 1.25 0.89 1967 800 1167 505 30300 0.20 0.1449 4405 11542 -7137 45 2700 1.07 0.76 2129 1029 1101 515 30900 0.20 0.1449 4492 11771 -7279 Reaches 55 3300 0.94 0.67 2272 1257 1015 525 31500 0.19 0.1378 4354 11999 -7645 Reach I Off site also applicable for Pre-Developed Tc 65 3900 0.84 0.60 2401 1486 915 535 32100 0.19 0.1378 4436 12228 -7791 Length 0.00 75 4500 0.77 0.55 2518 1714 804 545 32700 0.18 0.1306 4285 12456 -8171 K 420.00 85 5100 0.71 0.50 2626 1943 684 555 33300 0.18 0.1306 4364 12685 -8321 Slope (ft/ft) 0.0400 be sure this is decimal equivalent slope 0.0000 95 5700 0.66 0.47 2727 2171 556 565 33900 0.17 0.1235 4200 12913 -8714 Travel Time 0.00 Minutes 105 6300 0.62 0.44 2822 2400 422 575 34500 0.17 0.1235 4274 13142 -8868 115 6900 0.58 0.42 2911 2628 282 585 35100 0.16 0.1164 4097 13371 -9273 Reach 2 Finished Lot from House to Street 125 7500 0.55 0.39 2995 2857 138 595 35700 0.16 0.1164 4167 13599 -9432 Length 30.00 135 8100 0.53 0.37 3076 3086 -10 605 36300 0.15 0.1093 3977 13828 -9850 K 420.00 145 8700 0.50 0.36 3152 3314 -162 615 36900 0.15 0.1093 4043 14056 -10013 Slope (ft/ft) 0.0400 be sure this is decimal equivalent slope 0.0000 155 9300 0.48 0.34 3226 3543 -317 625 37500 0.14 0.1021 3841 14285 -10444 Travel Time 0.36 Minutes 165 9900 0.46 0.33 3297 3771 -475 635 38100 0.14 0.1021 3902 14513 -10611 175 10500 0.45 0.32 3365 4000 -635 645 38700 0.13 0.095 3687 14742 -11055 Reach 3 Gutter Flow to Inlet/Catch Basin 185 11100 0.43 0.31 3430 4228 -798 655 39300 0.13 0.095 3744 14970 -11227 Length 300.00 195 11700 0.42 0.30 3494 4457 -963 665 39900 0.12 0.0879 3516 15199 -11683 K 2400.00 205 12300 0.40 0.29 3555 4685 -1130 675 40500 0.12 0.0879 3568 15428 -11859 Slope (ft/ft) l.0000 be sure this is decimal equivalent slope 0.0000 215 12900 0.39 0.28 3615 4914 -1299 685 41100 0.11 0.0808 3328 15656 -12329 Travel Time 0.13 Minutes 225 13500 0.38 0.27 3673 5143 -1470 695 41700 0.11 0.0808 3376 15885 -12509 235 14100 0.37 0.26 3729 5371 -1642 705 42300 0.10 0.0736 3122 16113 -12991 Reach 4 Pipe Flow Pipe Reach One (only need one if no Dia change) 245 14700 0.36 0.26 3784 5600 -1816 715 42900 0.10 0.0736 3166 16342 -13175 Length 20.00 255 15300 0.35 0.25 3837 5828 -1991 725 43500 0.09 0.0665 2900 16570 -13670 K 3000.00 12-inch Pipe minimum 265 15900 0.34 0.24 3889 6057 -2168 735 44100 0.09 0.0665 2940 16799 -13859 Slope (ft/ft) 0.0200 Average Slope for total pipe run 275 16500 0.33 0.24 3940 6285 -2345 745 44700 0.08 0.0594 2660 17027 -14367 Travel Time 0.05 Minutes 285 17100 0.33 0.23 3990 6514 -2524 295 17700 0.32 0.23 4038 6742 -2704 "1815A" TREATMENT REQUIREMENTS Reach 5 Pipe Flow Add additional pipe reacheds for other Dia 305 18300 0.31 0.22 4086 6971 -2885 Minimum "1815A" Volume Required 683 cu ft Length o.oo 315 18900 0.31 0.22 4132 7200 -3067 Provided Treatment Volume -Min. 4,440 cu ft K 3900.00 15/18-inch Pipe 325 19500 0.30 0.21 4178 7428 -3250 STORAGE REQ. -100 YEAR DESIGN STORM Slope (ft/ft) 0.0050 Average Slope for total pipe run 335 20100 0.29 0.21 4223 7657 -3434 Maximum Storage Required by Bowstring 1,205 cu ft Travel Time 0.00 Minutes 345 20700 0.29 0.21 4267 7885 -3618 Provided Pond Storage Volume to Inlet -Min 14,540 cu ft 355 21300 0.28 0.20 4321 8114 -3793 Provided Stormtec Storage Volume 1,798cuft Sum of Tc 0.53 Minutes 365 21900 0.27 0.19 4286 8342 -4057 Total Provided Volume 16,338 cu ft 375 22500 0.27 0.19 4402 8570.9 -4169 Tc for Analysis 5.00 Minutes 385 23100 0.26 0.19 4354 8799.4 -4446 Whipple Consulting Engineers INFILTRATION CALCULATIONS Pond Bottom Area Infiltration Rate Outflow Stormtech Chamber System 468 sf 3.07E-04 els/sf 0.1436760 els SC-740 Length (ft) Width (ft) Height unit dim 7.5 3.825 2.5 ends/sides 2 2 PROJECT: BASIN: DESIGNER: DATE: Ponderosa COSV B trw 01/03/23 Pond Drains In 72 Hrs Depth volume 0.5 ft 234 cf [Time 1628.66 sec I 0.45 hrs Rows Columns Note: Chambers in this scenario are spred out in three locations 4 6 Length Width Height Gallery Bottom Area Perimeter Area Total Area Infiltration Rate Outflow 30.44 Gravel Volume in Gallery 24 Units 2.8 cy/unit 67.2 cy Whipple Consulting Engineers 27.45 3.5 835.578 405.23 1240.808 3.07E-04 0.3809281 els Foundation Depth 6 in Storage 24 Units 74.9 cf/unit Foundation Depth 6 in 1797.6 cf Storage Provided StonnTech SC-740 Chamber SC-740 C..Ntln St.rate Ytl•es Per C-r ~-40" Staie Poioslty. Galoolat/on1 Bra BaMKi 1.-P>n • 6' (150rrrn) 9one8iue Undtl</hQ Chambers. SC.740 CllMI-st.,... Yo-. Per C._., (e11t.) Bli111i}!l'fl ~--·---~~--.-. ltJle:-.Atld U3cv. It (Q03lm? ofU>r/lf/tltrtldJ•-indl (25 "'"'of •kine ilundllon. a. .. Cumber aad Stone CUl11ber Stoo• i;:~.:;-oept11 Stonge tl'(m') 6 (1501 I 12 (3001 11a (4501 Storm Tedi SC-740 45.9(13) 74.912-1) I m (2.3) I 8114 (2..5! Note:1tssumeso(l5/Jmm)olst111ubooedurn1><ts, 0(15/Jmm) lllrrS/Jl'*'t/lrdmpa111it,'. -tofSlttlePer~ller r111•!.i.,.,,-n..: INSTAU.EC CHAMSER SYSTEM StWJ. P'ROVl::E THE'-°"° FACTORS SPECIFIED IH THE MSHTO LRfO BRSOGE CES4Gfril SPECIFICATIONS SECTION t1',t2 FOR EARnt ,_,., lN'E LMOS, WllH ~OEAATION i7.()ft IMPACT AHO MULl!PlE VE)tlct.£ PRESENCES. 9 Cd SbTtlTec:n a1 860.529..1111 ot ll&.192..2694 0t vtll OU' 'N!t>lke .i www.atcrmtKh.com f0t ~and prodr.lce lr.bm.uon. 2 1fJtt7 ~!?U\OU~ l>z+1tJkf::rE. 12.;~ 27 -S2. ~1u 'c, Storm Drainage Report FOR Ponderosa Temporary Fire Access Road Spokane Valley, WA November 2015 2014-1233 STORM DRAINAGE REPORT FOR PONDEROSA TEMPORARY FIRE ACCESS ROAD Spokane Valley, Washington November 2015 2014-1233 Prepared by: Whipple Consulting Engineers 2528 N. Sullivan Road Spokane Valley, WA PH: (509) 893-2617 FAX: (509) 926-0227 This report has been prepared by Nick Harmon, EIT of Whipple Consulting Engineers under the direction of the undersigned professional engineer whose seal and signature appears hereon: Todd R. Whipple, P.E. INTRODUCTION: The purpose of this drainage report is to identify drainage impacts resulting from the proposed development for the Ponderosa Temporary Fire Access Road. This drainage report will determine the drainage infrastructure improvements that are necessary to control and treat the stormwater runoff from the project site. The proposed project lies within the City of Spokane Valley and will be designed in accordance with the Spokane Regional Stormwater Manual (SRSM). Due to the well-draining onsite soil beneath the proposed ponds, treatment methods will be based on equation 6-lc:, V=l 133A, as outlined in the SRSM. NARRATIVE: PROJECT DESCRIPTION: The proposed project is a Fire access road that will be open to the public daily traffic and will connect Farr Road to Ponderosa Lane. The site is currently undeveloped and covered with field grass, weeds and pine trees. The proposed roadway will be not only for fire department access during an emergency but also as a public access while the phases of development continue. The roadway will be paved and will include the associated storm drainage facilities. The proposed stormwater facilities will adequately collect, treat and discharge the stormwater runoff from the proposed development. The proposed project is located between Ponderosa Lane and Farr Road along the 47th A venue alignment. The site is located within the City of Spokane Valley and lies in the NE 1A of Section 5, T 24 N., R 44 E., W.M. The parcel numbers for the project are 44052.9228 and 44052.9011. A vicinity map is attached in the Appendix. GEOTECHNICAL INFORMATION: As can be seen from the accompanying soils map from the United States Department of Agriculture (USDA), Web Soil Survey 2.0 as performed by the Natural Resources Conservation Service (NRCS), the site consists of three different soil types. The site soils are as follows: 3121 Marble loamy sand, 8 to 15 percent slopes, This series consists of deep, well drained soils. The permeability for this soil type is moderately high to very high. This soil is classified as Soil Group Type A within the Spokane Regional Stormwater Manual appendix 5E. 7122 Urban land Marble, disturbed complex, 8 to 15 percent slopes, This series consists of deep, well drained soils. The permeability for this soil type is high to high. This soil previously known as Bemhill silt loam is classified as Soil Group Type B within the Spokane Regional Stormwater Manual appendix 5E. Test Pits and a geotechnical evaluation was completed on site by IPEC and reported in the July 17, 2014 Geotechnical Evaluation Letter. Within the report, the soils of the web soil survey were Whipple Co11s11lting Engineers, Inc. Page 1of5 Ponderosa Ridge Fire Access · Drainage Report generally confirmed. An infiltration test was also completed and reported within the letter. Within the letter the area west of the ridge is recommended for drywell installation with design infiltration set at 0.3 cfs for a type A drywell and 1.0 cfs for a type B drywell. For the area to the east of the ridge the gravel gallery design infiltration rate is 3.70 x 104 cfs/sf. The soils will be verified at the exact pond locations at time of construction as noted on the plans. PRE-DEVELOPMENT BASIN INFORMATION: As shown on the Pre-Developed Basin Map located in the Appendix, the site gradually slopes generally from the south to the north and both east and west from high point located along the road alignment. T bl l P D I a e -re-eve opment P . s·t B . S roJect 1 e asm ummary Total Basin Impervious Area Area (sf) (sf) Pervious Area (sf) Pre-Basin A 279,247 0 279,247 Pre Basin B 66,637 0 66,637 Refer to basin calculat1ons in Appendix for areas and peak fl ows for all basins. From the existing ground contours, it appears that the excess stormwater that did not absorb into the soil generated in the pre-developed condition continues to flow to the north. POST-DEVELOPMENT BASIN INFORMATION: The Post-Development basins were separated into four (4) basins divided evenly on each side of the roadway. The Post-Development basins are defined by designed finish grades and storm drain facilities. Overall the project site has four (4) basins determined by first, site grading and second, treatment and discharge ponds. A copy of the basin map and calculations are included in the appendix with a summary provided in the following table. Whipple Co11sulti11g Engineers, Inc. Page 2 of5 Ponderosa Ridge Fire Access -Drai11age Report T bl 2 P t D a e -os ~ eve opmen ro_1ec I e asm t P . t s·t B . S ummary Total Basin Impervious Area Area (s0 (sO Pervious Area (sO Basin A 251,379 7,564 243,815 Basin B 27,868 7,679 20,189 Basin C 62,085 1,638 60,447 BasinD 4,552 1,786 2,766 (Method 1133A (ac)) PGIS Area (sf) Treatment AreaN olume (square feeUcubic feet) Required Provided Basin A and B 15,243 793/396 1000/547 Basins C and D 3,424 178/89 420/241 Refer to basin calculations in Appendix for areas and peak flows for all basins. *Note: The pond that will collect and discharge the water captured in Basins C and D was approved and called out in the construction plans for the Ponderosa Ridge Fire Access Grading Permit Plans and will be constructed at the time the temporary access road is constructed. Operational Characteristics: The stormwater generated within the basins of this site will sheet flow across the pavement to a ditch lined with dryland grass where it will then be collected by the proposed storm drainage ponds. The stormwater will be treated in each pond until the depth reaches 6 inches. Once the stormwater exceeds a height of 6 inches, it will spill into the drywell and be discharged underground as required per the Spokane Regional Stormwater Manual. Methodology: As required by the SRSM, the storm drainage facilities proposed for this site have been sized to attenuate the 10-and 25-year storm events using the Rational Method as outlined in Section 5.5 of the SRSM. Due to the small size of the basins within this analysis, the Rational Method has been used to calculate peak flows and volumes. The peak flows and volumes for these storm events are shown in the calculations that are included within the Appendix of this report. Water Quality Treatment: The proposed storm drainage pond has been designed to provide treatment volume based on Equation 6-lc (V::;ll33A) of the SRSM, as outlined in Section 6.7.1. Once the treated stormwater exceeds a height of 6 inches, it will spill into drywells, where it will be discharged underground. Whipple Co11sulti11g Engineers, Inc. Page 3 of 5 Ponderosa Ridge Fire Access -Drainage Report Critical Areas: Based on the Critical Area Maps provided by Spokane County, (DNR Streams, Fish and Wildlife, Wetlands, Geo-hazard Area and Critical Aquifer Resource Area), there does not appear to be any critical areas on site. No inventoried wetlands or federal flood zones are present within the project site. Down-Gradient Analysis: A down-gradient analysis is not needed for this site, as the Post-Development condition of the drainage area will be contained within the proposed ponds and are anticipated to contain the 25 year storm without discharge to the downslope properties. Results: As shown in Table 2 within this report we have provided the required treatment volume for the improvements proposed for the development. Table 3 below shows the onsite pond/swale storage summary for the 25-year storm events. T bl 3 P . s· P d/S I S a e -ro.1ect 1te on wae tora2e S mary um 25-YR Storm Required Provided Basin Vol. (cf) Vol. (cf) A+B 1,133 1,190 C+D 393 1,922 NOTE: Pond Bottom Infiltration was not accounted for wi1hin the Bowstring Calculations Pond for Basins C and D was approved in plans for Ponderosa Ridge Fire Access Grading Permit Plans. This pond will be constructed with the temporary access road and will adequately store and discharge the 25-year storm event as required by the SRSM. Ditch and Pipe Calculations Ditch and pipe calculations can be seen in the Appendix of this report. These calculations were based on the flows for the 50-year storm event to be conservative. Perpetual Maintenance of Facilities: This is residential development with a private road/fire access road as access. The ponds within the right of way surface maintenance will be provided by the homeowners. The City of Spokane Valley will not be liable for any maintenance or operation of the facilities. A maintenance plan will be provided to the owner if requested. Whipple Consultillg Engineers, Inc. Page4 of 5 Ponderosa Ridge Fire Access -Drainage Report Offsite Easements: There are no offsite easements required for this property. Regional Facilities: There are no known regional facilities that lie within the project site. No offsite regional facilities will be affected. CONCLUSION: As required by the City of Spokane Valley and the Spokane Regional Stormwater Manual, the onsite storm drainage facilities for this project will adequately collect, treat and discharge stormwater runoff generated by the site during the 25-year storm event. Whipple Cons11/ting Engineers, Inc. Page 5 of 5 Ponderosa Ridge Fire Access -Drainage Report APPENDIX VICINITY MAP .. ... PRO.J #: 1 4· I 233 DATE: 06/ l I /14 CRAWN: BNG APPROVED: TRW FIC3 URE 1 u'I nedeem er Lutheran Preschool E C111 n1·ron Dr -:.<'"q· '?)mor()n Dr ~ lt en ~ c: 2. t'l ~ 111 E Q- :i;:i s. C •t4tt. Ave IE 44tll Alfe ~ ~ ~ l 8 CJ) ..., a:: V> Ill ~ ::I s:: [ 47th~ Eoll4llh A'Je Ill .., ~ :0 0.. EFerretor N P OJECT SITE STCRM DRAINAGE REPORT PONDEROSA RIDGE PONDER.CSA LN & 47TH AVE ALIGN SPOKANE VALLEY, WASHINGTON VICINITY MAP Ponderosa Ct!re Cente • P.n rksuong M lie iJ • w s E NOT TO SCALE /!WCE WHIPPLE CONSULTING ENGINEERS CIVIL ANO TRANSPORTATION ENGINEERING 2528 NORTH SULLIVAN ROAD SPOKANE VALLEY. WASHINGTON 99218 PH: S09-ll93-2617 FAX: 509-926-0227 BASIN MAPS l':IWCe_ WORK\2014 WCE PROJECI'S\2014-12)) L.°""llNI --..... l'UD (Ref 174) • l'bue 2\DWG\1'11l£ AOCESS 12\DWG\123)-Buia M1111.d~ Pltli BASIN MAP, I Iii 2120 LS I ~.S2: 1 s AM. niclth OJ :r N ~ .... Pl Pl ; PRE-DEVELOPMENT BASIN MAP PONDEROSA RIDGE 44TH AVENUE AND SCHAF'ER RD. SPOKANE COUNTY, WASHINGTON PRO.J #: 1233 ~WC E DATE: 1 1 - 1 2-1 5 DRAWN: NJH APPROVED: TRW WHIPPLE CONSULTING ENGINEERS CIVIL, STRUCTURAL ANO TRANSPORTATION ENGINEER1NG 2528 NORTH SULLIVAN ROAD SPOKANE VALLEY, WASl11NGTON99216 PH: 509-993-2617 FAX: 509-926-0227 P:\WCI!_ WOJU<.\2014 WCE PRO!~CTS\2014-llJl L~-·""°"""""PUP (Re( 114) • l'l>a• 2\DWG\ftl\E ACCESS #2\DWG\123J· s .. U. Mop.d"1f, PQSl' BASIN MAP.11112/2015 l0:5B6 AM, l>idh POST-DEVELOPMENT BASIN MAP PCNDERCSA RIDGE PONDEROSA RIDGE & 47TH AVE ALIGN SPOKANE COUNTY, WASHINGTON ----- PROJ #: 1233 ~WC E DATE: 11-1 S·l S DRAWN: NJH APPROVED: TRW WHIPPLE CONSULTING ENGINEERS CIVIL . STRUCTURAL N'IO TRANSPORTATION ENGINEERING 2528 NORTH SULLIVAN AO/\O SPOKANE VALLEY, WASHINGTON 99216 PH: 509-!!93-F : 7 BASIN SUMMARY SHEET Whipple Consulting Engineers Basin Calculation Worksheet WCE No. I 1/11/2015 14-1233 Ponderosa Ridge NJH Temp Fire Access Road Imp 0.9 Per 0.15 SPOKANE COUNTY· SRSM ·GRASSED PERCOLATION METHOD Intensities from SRSM eqn. 5-13. per Table 5-7, Assumes Tc = 5 min I (2 yr)= 1.418 inches I (10 yr)= 2.619 inches NOTE: 1 (25 yr)= 3.319 inches I (50 yr)= 3.843 inches I(lOOyr)= 4.381 inches tl33A C=CIA (cfs) Basin I Total I Access/Parking I Sidewalk I DY I Buildings Total Total Weiehled PGIS Pond Pond 2 yr 10 yr 25 yr 50 yr lOOyr sf I /Street (stl I sf I WY I sf Impervious Pervious "Cu sf Area (st) Vol (cf) PRE A I 279,2471 OI 0 0 0.00 279,247.00 0.15 0.00 0.00 0.00 1.36 2.52 3.19 3.70 4.21 PRE B I 66,6371 OI 0 0 0.00 66,637.00 0.15 0.00 0.00 0.00 0.33 0.60 0.76 0.88 1.01 I Pre Total 345,884 0 0 0 () 0.001 345,884.00 ().15 0.00 0.00 0.001 1.691 3.121 3.95~ 4.581 5.22 --~ ~.-.. ,' POST A 251.379 7,564 0 0 0 7,564.00 243.815.00 0.17 7.564.00 393.48 196.741 1.41 2.61 3.31 3.83 4.36 POSTB 27.868 7,679 0 0, 0 7.679.00 20.189.00 0.36 7,679.00 399.46 199.73 0.32 0.60 0.76 0.88 1.00 POSTC 62,085 1,638 0 ol 0 1.638.00 60,447.00 0.17 1,638.00 85.21 42.61 0.34 0.63 0.80 0.93 1.06 POSTD 4,552 1.786 0 QI 0 1,786.00 2,766.00 0.44 1,786.00 92.91 46.45: 0.07 0.12 0.15 0.18 0.20 TOTAL 345,884 18,667 0 0 OI 3,424.00J 327~217.00 1.141 18,667.00I 971.061 485.531 2.141 3.961 s.021 s.81 I 6.63 Post A+ B 279,247 15,243 0 0 OI 15.243.00I 264,004.00 o. 191 15,243.00I 792.941 396.471 1.741 1.211 4.061 4.701 5.36 PostC+D 66,637 3.424 0 0 OI 3,424.00I 63,213.00 0.191 3,424.00I 178.121 89.061 0.411 0.761 0.961 1.111 1.26 POND VOLUME WORKSHEET I WHIPPLE CONSULTING ENGINEERS PONDVOLUMECALCSHEET Project: 14-1233 Designer: NJH Ponderosa Temporary Fire Access Road Basins Ponds/ Bottom Squared Pond Pond Swales Area Side Bottom Drywell Elevation Elevation sf lf at Drywell A A 1000 31.62 1000.00 1000.50 C&D F 420 20.49 1000.00 1000.50 Date: 11/12/2015 Ti Pond Conic Side Total Conic Inlet Volume Slope Volume to Volume ElevatioIJ to Rim Volume to Rim to Inlet (avg) cf cf cf cf 1001.00 500 47 547 1,000 1002.53 210 31 241 1,063 Calculations for this pond were provided in previosely approved plans (shown here for verification of sizing) '----\! -,----.__ b" . '. .. ___::_~' -•UV\',( -r-i ..--=i I I I I I I II I I II S1 Side Total Slope Volume Volume to Inlet cf cf 190 1,190 787 1,850 -~~ I I I GRAVEL GALLERY WORKSHEET WHIPPLE CONSUL TING ENGINEERS GRAVEL GALLERY CALC SHEET 11/1212015 14·1233 ENGINEER Ponderosa Temporary Fire Access Road NJH Note: infiltration rates per IPEC Geohazard Evaluation July 17, 2014 Basins Pond/Swale Number Length Width of Gallef'les ft ft C&O F 2 20.00 3.00 Ground Gravel Water Gallery EL. Bott. EL ft ft . Foundation Gallery Porosity Depth Depth of Gravel Infiltration (Min) 'Min) {Typ) Rate ft ft cf/cf cfs/sf 0 2 0.3 3.70E·04 Volume Storage Perimeter Sidewall Bottom Outflow Volume Area Area cf cf ft sf sf cfs 240 72 92.00 184.00 120 0.1125 Galleries as designed in previousely approved plans for Ponderosa Rid<1e Fire Access Gradina Permit Plans (Basins C and F for Pond F in oreviouse pla1 ns) -. olj ~ .;: . r . -.: . . ... Totals 2 20 3 240 72 92.00 184.00 120.00 0.1125 Storage Volume = Volume• P0<osity Sidewall Area= Perimeter' Depth OutFlow = Sidewall Area+ Bottom Area • Infiltration Rate Note: Outflow Assumes a Full Gallery 25-YEAR STORM EVENT BOWSTRING CALCULATIONS SRSM RATIONAL METHOD 25-Year Design Storm PROJECT: Ponderosa Temp Fire Access PROJECT INFORMATION BASIN: A and B Tot. Area Imp. Area Perv. Area Wt.C= 279,247 SF 15.243 SF 264,004 SF 0.19 6.41 Acres C= 0.9 C= PGISArea= 0.15 15.243 WCE Applicable Travel Time Ground Cover CoefficienL~ l'=r T•hlc S-' Sl<.$1\1 T·-of Cover K (ft/min) Shon P11s1ure 420 Nellflv Bare Ground 600 Small Roadside Ditch/ Ornss 900 Paved Area (use for parking lots) 1200 Guuer -4 inches deeo 1500 Guuer -6 inches deep 2400 Pioe-12-inch PVCJDI 3000 Pine -15/18-inch PVCJDI 3900 Pioe -24-inch PVC/DI 4700 Reaches Reach I Ol'fs1te also applicable for Pre-DcvcloDCd Tc Length 0.00 K 420.90 SI""" (fl/ft) OJ1490 be sure this is decim11I eauiv:ilem slope 0.0000 Travel Time o.oo Minutes Reach 2 Fmi>hcd Lot from House to Street Length 6412.()() K 420.00 Slope (rt/fl) O.Oc>25 bl: sure this is decimal equiv:llenc slODe 0.0000 Travel Time 5.73 Minules Rc:ich 3 Channel Lene.th 501.00 K 900.00 Slone {IVrl) 0.0809 be sure this is decim31 eauivalent slope 0.0000 Travel Time 1.97 Minuies Reat:h 4 Pme Flow I Pipe Rc~ch One (only need one if no Diam change) Lene.lh OJIO K 3000.00 12-inch Pi~ minimum Slone (ft/ll) o.oos9 Average Slooc for !Olol pipe run TrnvelTtrne 0.00 Minutes Reach 5 P1aeAow2 Add additio1ml pipe rcacheds for other Diam Length 11.CIO K 3900.00 l SI 18-inch Pioe Slope (fl/ft) 0.0050 Avcrolle Slope for toml pipe run Travel Time 0.00 Minutes Sum of Tc 7.70 Minules Tc f01" Analysis 7.70 Minutes Whipple consulting Engineers -BOWSTRING METHOD Time Increment (min) 5 Time of Cone. (min) 7.70 Outflow (cfs) 3 Design Year Flow 50 Area (acres) 6.41 Impervious Area (sq 11) 15243 'C' Factor 0.19 Area• C 1.224 PGIS Area 15.243 Time Time Inc. Jnrens. Q Devel Vol.In !min~ (sec) (in/hr) (els) (cu ft) 7.70 462 2.54 4.0692 2520 5 300 3.32 4.07 1636 10 600 2.16 2.64 1998 15 900 1.67 2.05 2165 20 1200 1.40 1.71 2322 25 1500 1.22 1.49 2466 30 1800 1.08 1.33 2599 35 2100 0.99 1.21 2722 40 2400 0.91 1.11 2837 45 2700 0.84 1.03 2945 50 3000 0.79 0.96 3046 55 3300 0.74 0.91 3143 60 3600 0.70 0.86 3235 65 3900 0.67 0.82 3323 70 4200 0.64 o.1a 3407 75 4500 0.61 0.75 3488 80 4800 0.59 0.72 3566 85 5100 0.57 0.69 3641 90 5400 0.55 0.67 3714 95 5700 0.53 0.65 3784 100 6000 0.51 0.63 3852 '1133A" TREATMENT AEQU IREMENTS Minimum "1133A" Volume Required Provided Treatment Volume -Min. PROJECT: Ponderosa Temp Fire Ac BASIN: A and B DESIGNER TRW DATE: 11-Nov-15 Rainfall lntenslly Coefficients for Spokane taken from Table 5-7 SRSM ~= 9.09 N~s~ 0.625 Flow (weighted C) Qwe= 4.07 cfs Flow (time of Concentration) Qte= Vol.Out (cul1) 13!!6 900 1800 2700 3600 4500 5400 6300 7200 8100 9000 9900 10800 11700 12600 13500 14400 15300 16200 17100 18000 1.05 els Storage (cu ft) 1133 == 736 198 -535 -1278 -2034 -2801 -3578 -4363 -5155 -5954 -6757 -7565 -8377 -9193 -10012 -10834 -11659 -12486 -13316 ·14148 396 cu tt 547 cu ft DAYWELL REQUIREMENTS -50 YEAR DESIGN STORM Maximum Storage Required by Bowstring Provided Storage Volume to Inlet -Mlnumum Number and Type of Drywalls Required 1133 cu ft 1,190cu11 O Single 3 Double SRSM RATIONAL METHOD 2.5-Year Design Storm PROJECT: Ponderosa Temp Fire Access PROJECT INFORMATION BASIN: C and D Tot. Area Imp.Area Perv. Area Wt.C= 66,637 SF 3,424 SF 63,213 SF 0.19 1.S3 Acres C= 0.9 C= 0.1S PGIS Area = 3,424 WCE Applicable Travel Time Ground Cover Coefficient~ l\:r T1tbh: , .. 6 SK.SM Tv~ ofCovtt K lfllmiru Shon P:lslure 420 Nearly Bare Ground 600 Small Roodsidc Dirchl Grass 900 Paved Area (use ror pari.ing lots) 1200 Guucr -4 inches deeo 1500 Gu lier -6 inches deep 2400 Pipe -12-inch PVC/DI JOOO Pipe -15/ I 8-inch PVCJD I 3900 Pipe -24-inch PVC/DI 4700 Reaches Reach I Off site also aoolicable for Pre-Developed Tc Leni:tb 0.00 K 420.00 Slope (ft/ftl 0.0400 be sure !his is d«im:il equivalent slope 0.0000 rrravcl Tame 0.00 Minutes Reach 2 Finished Lor from House 10 Slre1<l Len21h 418.00 K 420.00 Slope (ft/ft) 0.11625 be sure lhis is decimal equtvnlcnt slope 0.0000 Travel Time 3.98 Minu!es Reach 3 Channel l..en111h 129.00 K 900.00 s l<>Q• (fl/fl) 0.118110 be sure lhis is decimal equivaltnl slope 0.0000 Travel Time 0.51 Minutes Reach -I Pio~ Flow I P•!le Reach One (only need one ii no Diam ch:mae) Length 0.00 K 3000.00 12-incb Pipe minimum Slone (ft/fl) 11.110511 Avernc SI""" for total oioe run Tra\•el Time 0.00 Minutes ~each 5 PipcAow2 Add addi1ional oioe reachells for olher Diam Len 11th 0.00 K 3900.00 15/t8-inch Pipe Slope (fl/fr) 0.0050 Avera!fe Slope for IO(ol oic e run Travel lime 0.00 Minutes Sum of Tc 4.49 Minutes re for Analym 5.00 Minuies Whipple Consulting Engineers ·--BOWSTRING METHOD PROJECT: Ponderosa Temp Fire At. BASIN: Cando DESIGNER TRW DATE: 12-Nov-15 Time Increment (min) 5 Rainfall Intensity Coefficients for Spokane Tlme of Cone. (min) 5.00 taken from Table S-7 SRSM Outflow (els) 0.1125 M2~= 9.09 Design Year Flow so Nzs = 0.62S Area (acres) 1.53 lmpeivious Area (sq ft) 3424 Flow (weighted C) 'C'Factor 0.19 Qwc= 0.96 cfs Area• C 0.288 Flow (time ol Concentration) PGIS Area 3,424 Ole= 0.24 els Time Time Inc. lntens. Q Devel Vol.In Vol.Out Storage (min) (sec) (in/hr) (els) (CUI!) (cu It) (cu It) 5.00 300 3.32 0.9588 385 34 352 5 300 3.32 0.96 385 33.75 352 10 600 2.16 0.62 436 67.5 369 15 900 1.67 0.48 484 101.25 382 20 1200 1.40 0.40 525 13S 390 25 1500 1.22 0.3S S62 168.75 393 <== 30 1800 1.08 0.31 S95 202.5 393 35 2100 0.99 0.28 626 236.25 389 40 2400 0.91 0.26 6S4 270 384 45 2700 0.84 0.24 6BO 303.75 377 50 3000 0.79 0.23 705 337.5 368 SS 3300 0.74 0.21 729 371.25 358 60 3600 0.70 0.20 751 40S 346 65 3900 0.67 0.19 772 438.75 334 70 4200 0.64 0.18 793 472.5 320 75 4500 0.61 0.18 812 S06.25 306 80 4800 O.S9 0.17 831 S40 291 BS 5100 0.57 0.16 849 573.75 275 90 5400 0.55 0.16 866 607.5 259 9S 5700 0.53 0.15 883 641.25 242 100 6000 O.S1 0.15 900 67S 225 "1133A" TREATMENT REQUIREMENTS Minimum "1133A" Volume Required 69 cult Provided Treatment Volume • Min. 547 cu ft DRYWELL REQUIREMENTS -SO YEAR DESIGN STORM Maximum Storage Required by Bowstrtng 393 cu ft Provided Storage Volume to Inlet -Minumum 1.922 cu ft Graver Galleries CUL VERT CALCS & DITCH CALCS Channel Report Hydraflow Express Extension for Autodesk® Auto CAD® Civil 30® by Autodesk, Inc. Basin A Circular Diameter (ft) Invert Elev (ft) Slope(%) N-Value Calculations Compute by: Known Q ( cfs) Elev (ft) 102.00 0 = 1.50 = 100.00 = 1.00 = 0.024 Known Q = 3.83 1 Highlighted Depth (ft) Q (cfs) Area (sqft) Velocity (ft/s) Wetted Perim (ft) Crit Depth, Ye (ft) Top Width (ft) EGL (ft) Section 2 Reach (ft) Thursday, Nov 12 2015 = 0.90 = 3.830 = 1.11 = 3.45 = 2.66 = 0.75 = 1.47 = 1.09 3 Channel Report Hydra flow Express Extension for Autodesk® AutoCAD® Civil 30® by Autodesk, Inc. Basin C Circular Diameter (ft) Invert Elev (ft) Slope(%) N-Value Calculations Compute by: Known Q (cfs) Elev (ft) 100.00 0 = 1.00 = 100.00 = 1.00 = 0.024 Known Q = 0.93 1 Highlighted Depth (ft) Q (cfs) Area (sqft) Velocity (ft/s) Wetted Perim (ft) Grit Depth, Ye (ft) Top Width (ft) EGL (ft) Section 2 Reach (ft) Thursday, Nov 12 2015 = 0.49 = 0.930 = 0.38 = 2.42 = 1.55 = 0.41 = 1.00 = 0.58 Depth (ft: 3 Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 30® by Autodesk, Inc. Basin A Triangular Side Slopes (z: 1) Total Depth (ft) Invert Elev (ft) Slope(%) N-Value Calculations Compute by: Known Q (cfs) Elev (ft) 0 1 = 3.00, 3.00 = 1.00 = 100.00 = 8.00 = 0.027 Known Q = 3.83 2 Section 3 4 Reach (ft) Highlighted Depth (ft) Q (cfs) Area (sqft) Velocity (ft/s) Wetted Perim (ft) Grit Depth, Ye (ft) Top Width (ft) EGL (ft) 5 6 7 Thursday, Nov 12 2015 = 0.48 ::: 3.830 = 0.69 = 5.54 ::: 3.04 = 0.64 = 2.88 = 0.96 8 Depth (ft) Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 30® by Autodesk, Inc. Basin B Triangular Side Slopes (z: 1) Total Depth (ft) Invert Elev (ft) Slope(%) N-Value Calculations Compute by: Known Q ( cfs) Elev (ft) 0 1 = 3.00, 3.00 = 1.00 = 100.00 = 8.00 = 0.027 Known Q = 0.88 2 Section 3 4 Reach (ft) Highlighted Depth (ft) Q (cfs) Area (sqft) Velocity (ft/s) Wetted Perim (ft) Grit Depth, Ye (ft) Top Width (ft) EGL (ft) 5 6 7 Thursday, Nov 12 2015 = 0.28 = 0.880 = 0.24 = 3.74 = 1.77 = 0.36 = 1.68 = 0.50 8 Depth (ft) Channel Report Hydraflow Express Extension for Autodesk® Auto CAD® Civil 30® by Autodesk, Inc. Basin C Triangular Side Slopes (z: 1) Total Depth (ft) Invert Elev (ft) Slope(%) N-Value Calculations Compute by: Known Q ( cfs) Elev (ft) 102.00 101.50 0 1 = 3.00, 3.00 = 1.00 = 100.00 = 8.00 = 0.027 Known Q = 0.93 2 Section 3 4 Reach (ft) Highlighted Depth (ft) Q (cfs) Area (sqft) Velocity (ft/s) Wetted Perim (ft) Crit Depth, Ye (ft) Top Width (ft) EGL (ft) 5 6 Thursday, Nov 12 2015 7 = 0.28 = 0.930 = 0.24 = 3.95 = 1.77 = 0.36 = 1468 = 0.52 8 Depth (ft) 1.50 Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 30® by Autodesk, Inc. Basin D Triangular Side Slopes (z:1) Total Depth (ft) Invert Elev (ft) Slope(%) N-Value Calculations Compute by: Known Q (cfs) Elev (ft) 100.50 0 1 ;;;; 3.00, 3.00 = 1.00 = 100.00 ;;; 8.00 = 0.027 Known Q ;::: 0.18 2 Section 3 4 Reach (ft) Highlighted Depth (ft) Q (cfs) Area (sqft) Velocity (ft/s) Wetted Perim (ft) Crit Depth, Ye (ft) Top Width (ft) EGL (ft) 5 6 7 Thursday, Nov 12 2015 = 0.15 = 0.180 ;;;; 0.07 = 2.67 = 0.95 = 0.19 = 0.90 = 0.26 8 Depth (ft) July 17, 2014 Project No. 14-067 Mr. Lanzce Douglass IPEC Inland Pacific Engineering Company Geotechnical Engineering and Consulting Lanzce G. Douglass Constmction, Inc. 1402 East Magnesium Road Spokane,WA99217 Re: Geotechnical Evaluation Proposed Fire Access Road Parcel No. 44052.9011 Spokane Valley, WA Dear Mr. Douglass: As you authorized, we have completed a geotechnical evaluation for the proposed fire access road at the above-referenced site in Spokane Valley, Washington. The purpose of the evaluation was to evaluate the site soil, bedrock, and groundwater conditions to assist in design of a pavement section and stormwater management facilities. This report summarizes the results of our site investigation, engineering analyses and recommendations. PROJECT DESCRIPTION We understand that the proposed project will consist of constructing a roadway with stormwater management areas. Storm water runoff will be managed using infiltration swales with drywells or gravel galleries. At this time, we understand that the proposed roadway will be classified as a local access street by the City of Spokane Valley. AVAILABLE INFORM.A TION We were provided a sice plan for the project by Whipple Consulting Engineers, Inc. (WCE). This plan showed the proposed roadway in plan and profile view, property lines, proposed lots, ground smface elevation contours, and proposed drainage tracts. This plan was prepared by WCE and was dated June 17, 2014. P.O. Box 1566, Veradale, WA 99037 Phone 509-209-6262 Geotechnical Evaluation Ponderosa Fire Access Road Parcel No. 44052.9011 Inland Pacific Engineering Company Procedures FIELD EVALUATION Project No. 14-067 July 17, 2014 Spokane Valley, WA Page 2 A geotechnical engineer from Inland Pacific Engineering Company (IPEC) observed the excavation of five test pits at the site. The test pits were excavated on July 9, 2014 using a cracked backhoe operated by an independent firm working under subcontract to others. 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 not obtained as part of our scope. 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 pits encountered 6 inches to 1 foot of topsoil at the surface. Below the topsoil, Test Pits TP-1 through TP-3 encountered alluvial silty to poorly or well graded sands to their tennination depths. Test Pits TP-4 and TP-4 encountered glacially deposited poorly graded sands below the 3- foot depth which extended to depths of 8.5 and 5.5 feet, respectively. Weathered granite was encountered below these depths to the refusal depths of the test pits. Refusal is defined as the depth at which the excavation could not be advanced further. Refusal can be caused by boulders, bedrock, very dense soils, or obstructions. Because weathered bedrock was encountered in the test pits during excavation, it is our opinion that refusal was caused by intact bedrock. 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 40 to 120 feet. Geologic maps indicate the soils in this area consist primarily of glacially deposited sands over bedrock. According to the Soil Survey of Spokane County, the site soils are classified as Marble loamy sand and Urban land-Marble, disturbed complex. The native soils exposed in the test pits were consistent with the NRCS data. Field Permeability Testing A test pit permeability test was performed adjacent to Test Pit TP-2 July 9, 2014. The permeability test was performed in accordance with the Spokane Regional Stormwater Manual (SRSM) Appendix 4C procedures. Geotechnical Evaluation Ponderosa Fire Access Road Parcel No. 44052.9011 Inland Paci fic Engineering Company Project No. 14-067 July 17, 2014 Spokane Valley, WA Page 3 The following table summarizes the results of the test performed. Test Location Depth uses Percent Fines Infiltration (feet) Classification Rate ( cfs/ft2) P-1 (TP-2) 3-5 SW-SM 8.6 7.76 x 104 A Data sheet summarizing the test performed is attached. The above results do not include a safety factor. 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. ANALYSIS AND RECO.MMENDATIONS 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 and/or gravel galleries would be suitable for infiltration of stormwater. Drywell Recommendations We estimated a design outflow rate for drywells using the Spokane 200 Method from the Spokane Regional Stormwater Manual (SRSM) for Test Pit TP-2. The following table summarizes the results of the analysis. Hydraulic Recommended Design Test Depth uses Percent Conductivity Drywell Outflow Rate Pit (feet) Classification Fines (cfs) (emfs) Type A TvueB TP-2 12-14 SP 4.0 4.9 x 10·2 0.3 1.0 These recommended design outflow rates include a safety factor of 1.3 as recommended by the SRSM. Higher design outflow rates may be possible if full-scale drywell tests are performed. Gravel Gallery Recommendations Based on the data obtained from the test pits, field permeability test, and laboratory tests perfonned, it is our opinion that swales and gravel galleries would also be suitable for infiltration of stormwater. For design, we recommend using the following infiltration rate for design of gravel galleries. 1. Test P-1: 3.70 x 104 cfs/ft2 Geotechnical Evaluation Ponderosa Fire Access Road Parcel No. 44052.9011 Inland Pacific Engineering Company Project No. 14-067 July 17, 2014 Spokane Valley, WA Page4 This recommended design infiltration rate includes a safety factor of 2.1 as recommended by the SRSM. Infiltration would be through the sides and bottoms of the gallery trenches. Pavement Based on the test pit and laboratory test data, the subgrades for roadways will consist primarily of silty sands once the topsoil has been removed. For a local access road, we recommend a pavement section consisting of 3 inches of asphalt overlying 6 inches of crushed aggregate base. This is the minimum pavement section required according to the City of Spokane Valley Street Standards. It is our opinion that this recommended pavement section will provide adequate support for emergency vehicles. After stripping any topsoil or existing fill, we recommend that the upper 8 inches of the resulting subgrade 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 determined 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 subgrade soils. We recommend that the subgrade surface be shaped to provide for positive drainage to minimize the potential for water to pond in the subgrade. Because the site soils are low to moderately frost-susceptible, it will be important to avoid creating "bathtubs" in the subgrade where water can pond and freeze, which could heave the pavement. 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. We recommend specifying crushed gravel 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 of WSDOT Standard Specification for Class V2 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. Geotechnical Evaluation Ponderosa Fire Access Road Parcel No. 44052.9011 Inland Pacific Engineering Company REMARKS Project No. 14-067 July 17, 2014 Spokane Valley, WA Page 5 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 reconunendations 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. Engineering Company 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-1 through TP-5 Descriptive Terminology Field Permeability Test Results Laboratory Test Results FIGURE 1 Site Location Map IPEC Project No. 14-067 Proposed Fire Access Road July 16, 2014 I.nland Pacific Engineering Comp.any Parcel No. 44052.9011 Geotecbnical EnPieering and Consulting Spokane Valley, WA FIGURE2 NRCSMap IPEC Project No. 14-067 Proposed Fire Access Road July 16, 2014 lnland Pacific En~euing Compmy Parcel No. 44052.9011 ~ottclmiaJ In!ineeiing and Consulting Spokane V allev, WA I / ,, I I IPEC Inland Pacific Enginttrlng Comp my Geoteclmical Engineering and Consulting FIGURE3 Test Pit Location Map Proiect No. 14-067 Proposed Fire Access Road July 16, 2014 Parcel No. 44052.9011 Spokane Valley, WA 1--·-------1 I ' 'j I I: l' I l 'Ii I I • I rro .. 11: i). 1 I 1 ... r I I I '101 '< 111;1! \ ~ /\ 1 I~ 1!1·1 : I E1-1 I ,l I ------·-; \ \ n \ LOG OF TEST PIT IPEC PROJECT: ELEV. DEPTH 0.0 0.5 2.0 7.0 14·067 Geotechnical Evaluation Proposed Fire Access Road Parcel No. 44052.9011 Spokane Valley, WA ASTM 02487 DESCRIPTION OF MATERIALS Symbol Inl:md Pacific Tugin~erin.g Comp:rny Geotechnical Enginming and Consulting TEST PIT: TP-1 LOCATION: See Test Pit Location Map DATE: 7/9/14 I SCALE: 1"=2' WL TESTS OR NOTES SM SILTY SAND, fine grained, with roots, dark brown, moist. (Topsoil} SM ;:,1L1 r ;:,ANLJ, rme gramea, Drown, moist. (Alluvium) POORLY GRADED SAND WITH SILT, fine grained, brown, moist. (Alluvium) SP·SM End of test pit. Groundwater not encountered. Test pit immediately backfilled. LOG OF TEST PIT PROJECT: 14-067 Geotechnical Evaluation Proposed Fire Access Road Parcel No. 44052.9011 Spokane Valley, WA ELEV. DEPTH ASTM 02487 DESCRIPTION OF MATERIALS 0.0 Symbol SM SILTY SAND, fine grained, with roots, brown, moist. (Topsoil) 1.0 Sil TY SAND, fine grained, brown, moist. (Alluvium) SM 3.0 IPEC Inland Pacific En~e-.elin.g Compmy Geoteclmical EnJ:Pneering md Consulting TEST PIT: TP-2 LOCATION: See Test Pit Location Map DATE: 7/9/14 !SCALE: 1"=2' WL TESTS OR NOTES WELL GRADED SANO WITH SILT, medium grained, brown, moist. SW-SM {Alluvium) 5.0 POORLY GRADED SAND, fine grained, brown, moist. (Alluvium) SP End of test pit 15.0 Groundwater not encountered. Test pit immediately backfilled. LOG OF TEST PIT IPEC PROJECT: ELEV. DEPTH 0.0 0.5 2.5 4.0 6.0 Inl:md Pacific Enginet!li:n_g Comp:my Geotechnic.al Engineering and Consulting 14~067 TEST PIT: TP-3 Geotechnical Evaluation LOCATION: See Test Pit location Proposed Fire Access Road Parcel No. 44052.9011 Map Spokane Valley, WA DATE: 7/9/14 I SCALE: 111=2' ASTM 02487 DESCRIPTION OF MATERIALS WL TESTS OR NOTES Symbol SM Sil lY SAND, fine grained, with roots, dark brown, moist. (Topsoil) Sil lY SAND, fine grained, brown, moist. SM {Alluvium) POORLY GRADED SANO WITH SILT, fine grained, brown, SP-SM moist. {Alluvium) POORLY GRADED SAND, fine to medium grained, brown, moist. SP (Alluvium) End of test pit Groundwater not encountered. Test pit immediately backfilled. LOG OF TEST PIT IPEC PROJECT: ELEV. DEPTH 0.0 1.0 3.0 8.5 9.5 Inl:md Pacific Engi.n~ering Comp:m)' ~otec:hnical EngineeriDg :ind Consulting 14·067 TEST PIT: TP-4 Geotechnical Evaluation LOCATION: See Test Pit Location Proposed Fire Access Road Map Parcel No. 44052.9011 Spokane Valley, WA DATE: 7/9/14 !SCALE: 1"=21 ASTM 02487 DESCRIPTION OF MATERIALS Wl TESTS OR NOTES Symbol SILTY SAND, fine to medium grained, with roots, dark SM brown, moist. (Toosoil) SILTY SAND, fine grained, brown, moist. SM (Alluvium) POORLY GRADED SAND, fine to medium grained, a trace of Gravel, Cobbles, and Boulders, brown, moist. (Glacial Outwash) SP GP POORLY GRADED GRAVEL, fine to coarse grained, light brown, moist. (Weathered Granit""\ Refusal Groundwater not encountered. Test pit immediately backfilled. LOG OF TEST PIT IPEC PROJECT: ELEV. DEPTH 0.0 1.0 3.0 5.5 6.5 14-067 Geotechnical Evaluation Proposed Fire Access Road Parcel No. 44052.9011 Spokane Valley, WA ASTM 02487 DESCRIPTION OF MATERIALS Symbol lnl:md P:i.cific Enjin~ering Company Geotechnic:il Engineering and Consulting TEST PIT: TP-5 LOCATION: See Test Pit Location Map DATE: 7/9/14 I SCALE: 1 '=2' WL TESTS OR NOTES SILTY SANO, fine grained, with roots, dark brown, moist. SM (Topsoil) SILTY SANO, fine grained, brown, moist. SM (Alluvium) POORLY GRADED SAND, fine to medium grained. (Alluvium) SP POORLY GRADED GRAVEL, fine to coarse grained, light GP brown, moist. {Weathered Granitel Refusal Groundwater not encountered. Test pit immediately backfilled. IPEC Inland Pacific Engineering Company Gcoteehnieal Engineedng and Consulting RELATIVE DENSITY OR CONSISTENCY VERSUS SPT N-V AL VE COARSE-GRAINED SOILS FINE-GRAINED SOILS DENSITY N(BLOWS/Ff) CONSISTENCY N(BLOWS/Ff) Very Loose 0-4 Very Soft 0-1 Loose 4 ·IO 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 uses SOIL CLASSIFICATION MAJOR DIVISIONS GROUP DESCRIPTIONS Coarse· Gravel and Gravel GW Well Graded Gravel Grained Gravelly Soils l••itbli11l,«r.ofi11c•l GP Poorly Graded Gravel Soils <50% coarse fraction Gravel GM Silty Gravel passes #4 sieve fwilh>l21Mi""s) GC Clayey Gravel <50% Sandy and Sand SW Well Graded Sand passes#200 Sandy Soils cwilhlink1.1tel)fuint SP Poorly Graded Sand sieve >50% coarse fraction Sand SM Silty Sand passes #4 sieve (with >12".i-fl.Rl!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 I Muck 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 Cobbles Gravel Sand Si It and Clay Coarse I Fine Coarse !Medium I Fine IPEC Inland Pacific Engineering Company Geotechnical Engineering and Consulting Test Pit Permeability Test Results Project Name: Ponderosa Fire Access Road Test Date: 7/912014 ------- Projecl Number: 14-067 Test Location: __ P;...·...;..l _.(T.;..;P;...-...;..2).___ Client: Lanzce G. Douglass Construction, Inc. Depth: ___ 3_' -_5_' __ _ Average Test Pi1 Dimensions: Length (ft): 4.50 Width (ft): 4.50 Depth (ft): __ 2 __ Elapsed Depth to Flow Volume Flow Infiltration Meter Time Time Water Reading of Water Rate Rate (seconds) (inches} (ft3) (ft3) (cfs) (cfs/ft2) 11:00 0 30.0 509.74 12:00 3600 28.5 560.70 50.96 l.42E-02 6.29E-04 12:10 600 28.5 571.18 10.48 l.75E-02 7.76E-04 12:20 600 28.5 581.65 10.47 l.75E-02 7.76E-04 12:30 600 28.5 592.12 10.47 l.75E-02 7.76E-04 12:31 60 30.0 Average Infiltration Rate: 7.76E-04 Depth to Water (inches) 27.5 +---.---.----..----,.-----. 11:00 12:00 12:10 12:20 12:30 12:31 Infiltration Rate (cfs/sq ft) 9.00€·04 .------------ 8.00E·04 r-----:~F;;;;;;;;;;;;;;;;;;;;-t;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;-. 7.00E-04 +~--==.,.....""--------- 600E-04 ~----------­ S.OOE-04 +------------ 4.00E-04 +------------ 3.00E-04 +------------ 2.00E·04 +------------ 1.00E·04 +------------ 0.00E+OO +----.-------..---~ ....-infiltration Rate (cfs/sq ft) 11:00 12;00 12:10 12:20 P.O. Box 1566, Veradale, WA 99037 Phone 509-209-6262 3" 314• #4 #10 #20 #40 #100 #200 100.00 I I I I I I ll\ 0 I I 90.00 i ' I I \ I 10 : I 80.00 I\ 20 p p 70.00 30 e e r r \ c c 60.00 40 e e n n \ I I 50.00 ' I 50 p A e a 40.00 I s I 60 \ a s i i 30.00 70 n n \ e 9 d 20.00 i"lo. I I 1~ 80 !'-.. .....__ 10.00 I " 90 0.00 100 100 10 1 0.1 0.01 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 L14-003 SW-SM· Well Graded Sand with Silt No. L14-003 IPEC Project: Ponderosa Fire Access Road GRAIN SIZE Location: p.1 (TP-2) @ 3, _ 5, Inland Pacific: Enginemng Campany REPORT Geotechnical Engineering and Consulting Job No.: Date: P.O Box 1566, Veradale, WA 99037 (509) 209-6262 14-067 7/11/2014 I 3• 314" #4 #10 #20 #40 #100 #200 I . I I I I I 100.00 I I I ~ I + I I I I 0 I I 11 ! ~ I i I 90.00 I \ 10 I I I 80.00 \I 20 p p 70.00 e I , I 30 e r r c c 60.00 e I l I 40 e \ n n t t 50.00 I 11 50 p \ R e a t s 40.00 I I 11 60 a s i i 30.00 n n \I I 70 e g d 20.00 \I 80 10.00 i'-I I "'-...... 90 ......_ -· 0.00 100 100 10 1 0.1 0.01 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 L14-004 J No. L14·004 SP· Poorly Graded Sand IPEC Project: Ponderosa Fire Access Road GRAIN SIZE Location: TP-2 @ 12, _ 14, Inland P:i.cific Enginttring Company REPORT Geote!chnical Engineering :wd Consulting Job No.: Date: P.O Box 1566, Veradale, WA 99037 (509) 209·6262 14-067 7/11/2014 I 3' 314' #4 #10 #20 #40 #100 #200 • I -I I I 100.00 w ......... ....... I 0 i I i ~ ~ I I I 90.00 ...... I I I I ""· ! ' 10 I B0.00 \ 20 I\ p p 70.00 e I I\ I 30 e r r c c 60.00 )i \I\ 40 e e n n I I 50.00 . \ 50 R p e a I\ I s 40.00 I \ 60 a s ~ i i n n 30.00 I '\ 70 e g I\ d ' 20.00 !lo 80 10.00 90 I 0.00 100 100 10 1 0.1 0.01 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 L14-005 SM -Silty Sand No. L14-005 IPEC Project: Ponderosa Fire Access Road GRAIN SIZE Location: TP-3 @ 1, _ 3, Inland Paci.ftc: Enginel!Iing Company REPORT Geotechnic:al Engineering and Consulting Job No.: Date: P.O Box 1566, Veradale, WA 99037 (509) 209-6262 14-067 7/11/2014 3" 3/4" #4 #10 #20 #40 #100 #200 100.00 I I I I ["'-. ~ NI, I j l I 0 ! i .. -I l 90.00 ~ ~ ~ ......... "I I i 10 I ~ l'l ! 80.00 ; ; \ 20 p p 70.00 e \ 30 e r r c c 60.00 40 e e n n t I 50.00 ~ 50 p ' R e a I 40.00 s \ I 60 a s i i n n 30.00 \ I 70 e 9 d 20.00 I I 80 \ 10.00 r-.. 90 I I r r---• 0.00 100 100 10 1 0.1 O.Q1 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 L14-006 SP -Poorly Graded Sand No. L14-006 IPEC Project: Ponderosa Fire Access Road GRAIN SIZE Location: TP-4 @ 3, _ 5, Inland Pacific E.ngjneBing Company REPORT Geotechnical Engineering and Consulting Job No.: Date: P.0 Box 1566, Veradale, WA 99037 (509) 209-6262 14-067 7/11/2014 United States Department of Agriculture A product of the National Cooperative Soil Survey, a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local participants Custom Soil Resource Report for Spokane County, Washington Natural Resources Conservation Service December 28, 2020 Preface Soil surveys contain information that affects land use planning in survey areas. They highlight soil limitations that affect various land uses and provide information about the properties of the soils in the survey areas. Soil surveys are designed for many different users, including farmers, ranchers, foresters, agronomists, urban planners, community officials, engineers, developers, builders, and home buyers. Also, conservationists, teachers, students, and specialists in recreation, waste disposal, and pollution control can use the surveys to help them understand, protect, or enhance the environment. Various land use regulations of Federal, State, and local governments may impose special restrictions on land use or land treatment. Soil surveys identify soil properties that are used in making various land use or land treatment decisions. The information is intended to help the land users identify and reduce the effects of soil limitations on various land uses. The landowner or user is responsible for identifying and complying with existing laws and regulations. Although soil survey information can be used for general farm, local, and wider area planning, onsite investigation is needed to supplement this information in some cases. Examples include soil quality assessments (http://www.nrcs.usda.gov/wps/ portal/nrcs/main/soils/health/) and certain conservation and engineering applications. For more detailed information, contact your local USDA Service Center (https://offices.sc.egov.usda.gov/locator/app?agency=nrcs) or your NRCS State Soil Scientist (http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/contactus/? cid=nrcs142p2_053951). Great differences in soil properties can occur within short distances. Some soils are seasonally wet or subject to flooding. Some are too unstable to be used as a foundation for buildings or roads. Clayey or wet soils are poorly suited to use as septic tank absorption fields. A high water table makes a soil poorly suited to basements or underground installations. The National Cooperative Soil Survey is a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local agencies. The Natural Resources Conservation Service (NRCS) has leadership for the Federal part of the National Cooperative Soil Survey. Information about soils is updated periodically. Updated information is available through the NRCS Web Soil Survey, the site for official soil survey information. The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or a part of an individual's income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require 2 alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (voice and TDD). To file a complaint of discrimination, write to USDA, Director, Office of Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410 or call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity provider and employer. 3 Contents Preface....................................................................................................................2 How Soil Surveys Are Made..................................................................................5 Soil Map..................................................................................................................8 Soil Map................................................................................................................9 Legend................................................................................................................10 Map Unit Legend................................................................................................11 Map Unit Descriptions.........................................................................................11 Spokane County, Washington.........................................................................13 3121—Marble loamy sand, 8 to 15 percent slopes.....................................13 7121—Urban land-Marble, disturbed complex, 3 to 8 percent slopes........14 7122—Urban land-Marble, disturbed complex, 8 to 15 percent slopes......16 References............................................................................................................19 4 How Soil Surveys Are Made Soil surveys are made to provide information about the soils and miscellaneous areas in a specific area. They include a description of the soils and miscellaneous areas and their location on the landscape and tables that show soil properties and limitations affecting various uses. Soil scientists observed the steepness, length, and shape of the slopes; the general pattern of drainage; the kinds of crops and native plants; and the kinds of bedrock. They observed and described many soil profiles. A soil profile is the sequence of natural layers, or horizons, in a soil. The profile extends from the surface down into the unconsolidated material in which the soil formed or from the surface down to bedrock. The unconsolidated material is devoid of roots and other living organisms and has not been changed by other biological activity. Currently, soils are mapped according to the boundaries of major land resource areas (MLRAs). MLRAs are geographically associated land resource units that share common characteristics related to physiography, geology, climate, water resources, soils, biological resources, and land uses (USDA, 2006). Soil survey areas typically consist of parts of one or more MLRA. The soils and miscellaneous areas in a survey area occur in an orderly pattern that is related to the geology, landforms, relief, climate, and natural vegetation of the area. Each kind of soil and miscellaneous area is associated with a particular kind of landform or with a segment of the landform. By observing the soils and miscellaneous areas in the survey area and relating their position to specific segments of the landform, a soil scientist develops a concept, or model, of how they were formed. Thus, during mapping, this model enables the soil scientist to predict with a considerable degree of accuracy the kind of soil or miscellaneous area at a specific location on the landscape. Commonly, individual soils on the landscape merge into one another as their characteristics gradually change. To construct an accurate soil map, however, soil scientists must determine the boundaries between the soils. They can observe only a limited number of soil profiles. Nevertheless, these observations, supplemented by an understanding of the soil-vegetation-landscape relationship, are sufficient to verify predictions of the kinds of soil in an area and to determine the boundaries. Soil scientists recorded the characteristics of the soil profiles that they studied. They noted soil color, texture, size and shape of soil aggregates, kind and amount of rock fragments, distribution of plant roots, reaction, and other features that enable them to identify soils. After describing the soils in the survey area and determining their properties, the soil scientists assigned the soils to taxonomic classes (units). Taxonomic classes are concepts. Each taxonomic class has a set of soil characteristics with precisely defined limits. The classes are used as a basis for comparison to classify soils systematically. Soil taxonomy, the system of taxonomic classification used in the United States, is based mainly on the kind and character of soil properties and the arrangement of horizons within the profile. After the soil 5 scientists classified and named the soils in the survey area, they compared the individual soils with similar soils in the same taxonomic class in other areas so that they could confirm data and assemble additional data based on experience and research. The objective of soil mapping is not to delineate pure map unit components; the objective is to separate the landscape into landforms or landform segments that have similar use and management requirements. Each map unit is defined by a unique combination of soil components and/or miscellaneous areas in predictable proportions. Some components may be highly contrasting to the other components of the map unit. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The delineation of such landforms and landform segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, onsite investigation is needed to define and locate the soils and miscellaneous areas. Soil scientists make many field observations in the process of producing a soil map. The frequency of observation is dependent upon several factors, including scale of mapping, intensity of mapping, design of map units, complexity of the landscape, and experience of the soil scientist. Observations are made to test and refine the soil-landscape model and predictions and to verify the classification of the soils at specific locations. Once the soil-landscape model is refined, a significantly smaller number of measurements of individual soil properties are made and recorded. These measurements may include field measurements, such as those for color, depth to bedrock, and texture, and laboratory measurements, such as those for content of sand, silt, clay, salt, and other components. Properties of each soil typically vary from one point to another across the landscape. Observations for map unit components are aggregated to develop ranges of characteristics for the components. The aggregated values are presented. Direct measurements do not exist for every property presented for every map unit component. Values for some properties are estimated from combinations of other properties. While a soil survey is in progress, samples of some of the soils in the area generally are collected for laboratory analyses and for engineering tests. Soil scientists interpret the data from these analyses and tests as well as the field-observed characteristics and the soil properties to determine the expected behavior of the soils under different uses. Interpretations for all of the soils are field tested through observation of the soils in different uses and under different levels of management. Some interpretations are modified to fit local conditions, and some new interpretations are developed to meet local needs. Data are assembled from other sources, such as research information, production records, and field experience of specialists. For example, data on crop yields under defined levels of management are assembled from farm records and from field or plot experiments on the same kinds of soil. Predictions about soil behavior are based not only on soil properties but also on such variables as climate and biological activity. Soil conditions are predictable over long periods of time, but they are not predictable from year to year. For example, soil scientists can predict with a fairly high degree of accuracy that a given soil will have a high water table within certain depths in most years, but they cannot predict that a high water table will always be at a specific level in the soil on a specific date. After soil scientists located and identified the significant natural bodies of soil in the survey area, they drew the boundaries of these bodies on aerial photographs and Custom Soil Resource Report 6 identified each as a specific map unit. Aerial photographs show trees, buildings, fields, roads, and rivers, all of which help in locating boundaries accurately. Custom Soil Resource Report 7 Soil Map The soil map section includes the soil map for the defined area of interest, a list of soil map units on the map and extent of each map unit, and cartographic symbols displayed on the map. Also presented are various metadata about data used to produce the map, and a description of each soil map unit. 8 9 Custom Soil Resource Report Soil Map 527290052729605273020527308052731405273200527326052733205273380527290052729605273020527308052731405273200527326052733205273380479110 479170 479230 479290 479350 479410 479470 479110 479170 479230 479290 479350 479410 479470 47° 36' 49'' N 117° 16' 41'' W47° 36' 49'' N117° 16' 22'' W47° 36' 32'' N 117° 16' 41'' W47° 36' 32'' N 117° 16' 22'' WN Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 11N WGS84 0 100 200 400 600 Feet 0 35 70 140 210 Meters Map Scale: 1:2,590 if printed on A portrait (8.5" x 11") sheet. Soil Map may not be valid at this scale. MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Map Unit Polygons Soil Map Unit Lines Soil Map Unit Points Special Point Features Blowout Borrow Pit Clay Spot Closed Depression Gravel Pit Gravelly Spot Landfill Lava Flow Marsh or swamp Mine or Quarry Miscellaneous Water Perennial Water Rock Outcrop Saline Spot Sandy Spot Severely Eroded Spot Sinkhole Slide or Slip Sodic Spot 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 The soil surveys that comprise your AOI were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: 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: Spokane County, Washington Survey Area Data: Version 12, Jun 4, 2020 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Jun 18, 2019—Jul 23, 2019 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. Custom Soil Resource Report 10 Map Unit Legend Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI 3121 Marble loamy sand, 8 to 15 percent slopes 16.2 89.6% 7121 Urban land-Marble, disturbed complex, 3 to 8 percent slopes 0.6 3.4% 7122 Urban land-Marble, disturbed complex, 8 to 15 percent slopes 1.3 7.0% Totals for Area of Interest 18.1 100.0% Map Unit Descriptions The map units delineated on the detailed soil maps in a soil survey represent the soils or miscellaneous areas in the survey area. The map unit descriptions, along with the maps, can be used to determine the composition and properties of a unit. A map unit delineation on a soil map represents an area dominated by one or more major kinds of soil or miscellaneous areas. A map unit is identified and named according to the taxonomic classification of the dominant soils. Within a taxonomic class there are precisely defined limits for the properties of the soils. On the landscape, however, the soils are natural phenomena, and they have the characteristic variability of all natural phenomena. Thus, the range of some observed properties may extend beyond the limits defined for a taxonomic class. Areas of soils of a single taxonomic class rarely, if ever, can be mapped without including areas of other taxonomic classes. Consequently, every map unit is made up of the soils or miscellaneous areas for which it is named and some minor components that belong to taxonomic classes other than those of the major soils. Most minor soils have properties similar to those of the dominant soil or soils in the map unit, and thus they do not affect use and management. These are called noncontrasting, or similar, components. They may or may not be mentioned in a particular map unit description. Other minor components, however, have properties and behavioral characteristics divergent enough to affect use or to require different management. These are called contrasting, or dissimilar, components. They generally are in small areas and could not be mapped separately because of the scale used. Some small areas of strongly contrasting soils or miscellaneous areas are identified by a special symbol on the maps. If included in the database for a given area, the contrasting minor components are identified in the map unit descriptions along with some characteristics of each. A few areas of minor components may not have been observed, and consequently they are not mentioned in the descriptions, especially where the pattern was so complex that it was impractical to make enough observations to identify all the soils and miscellaneous areas on the landscape. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The objective of mapping is not to delineate Custom Soil Resource Report 11 pure taxonomic classes but rather to separate the landscape into landforms or landform segments that have similar use and management requirements. The delineation of such segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, however, onsite investigation is needed to define and locate the soils and miscellaneous areas. An identifying symbol precedes the map unit name in the map unit descriptions. Each description includes general facts about the unit and gives important soil properties and qualities. Soils that have profiles that are almost alike make up a soil series. Except for differences in texture of the surface layer, all the soils of a series have major horizons that are similar in composition, thickness, and arrangement. Soils of one series can differ in texture of the surface layer, slope, stoniness, salinity, degree of erosion, and other characteristics that affect their use. On the basis of such differences, a soil series is divided into soil phases. Most of the areas shown on the detailed soil maps are phases of soil series. The name of a soil phase commonly indicates a feature that affects use or management. For example, Alpha silt loam, 0 to 2 percent slopes, is a phase of the Alpha series. Some map units are made up of two or more major soils or miscellaneous areas. These map units are complexes, associations, or undifferentiated groups. A complex consists of two or more soils or miscellaneous areas in such an intricate pattern or in such small areas that they cannot be shown separately on the maps. The pattern and proportion of the soils or miscellaneous areas are somewhat similar in all areas. Alpha-Beta complex, 0 to 6 percent slopes, is an example. An association is made up of two or more geographically associated soils or miscellaneous areas that are shown as one unit on the maps. Because of present or anticipated uses of the map units in the survey area, it was not considered practical or necessary to map the soils or miscellaneous areas separately. The pattern and relative proportion of the soils or miscellaneous areas are somewhat similar. Alpha-Beta association, 0 to 2 percent slopes, is an example. An undifferentiated group is made up of two or more soils or miscellaneous areas that could be mapped individually but are mapped as one unit because similar interpretations can be made for use and management. The pattern and proportion of the soils or miscellaneous areas in a mapped area are not uniform. An area can be made up of only one of the major soils or miscellaneous areas, or it can be made up of all of them. Alpha and Beta soils, 0 to 2 percent slopes, is an example. Some surveys include miscellaneous areas. Such areas have little or no soil material and support little or no vegetation. Rock outcrop is an example. Custom Soil Resource Report 12 Spokane County, Washington 3121—Marble loamy sand, 8 to 15 percent slopes Map Unit Setting National map unit symbol: 2wdk Elevation: 1,560 to 2,500 feet Mean annual precipitation: 15 to 22 inches Mean annual air temperature: 45 to 50 degrees F Frost-free period: 100 to 140 days Farmland classification: Prime farmland if irrigated Map Unit Composition Marble and similar soils:75 percent Minor components:25 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Marble Setting Landform:Outwash plains Landform position (three-dimensional):Tread Down-slope shape:Linear Across-slope shape:Linear Parent material:Sandy glaciofluvial deposits Typical profile Oi - 0 to 1 inches: slightly decomposed plant material A - 1 to 4 inches: loamy sand E - 4 to 8 inches: loamy sand E and Bt1 - 8 to 27 inches: sand E and Bt2 - 27 to 53 inches: sand C - 53 to 60 inches: sand Properties and qualities Slope:8 to 15 percent Depth to restrictive feature:More than 80 inches Drainage class:Well drained Capacity of the most limiting layer to transmit water (Ksat):High to very high (5.95 to 19.98 in/hr) Depth to water table:More than 80 inches Frequency of flooding:None Frequency of ponding:None Available water capacity:Low (about 3.1 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 4s Hydrologic Soil Group: A Ecological site: F043AY509WA - Warm, Xeric, Sandy, Outwash Terraces and Plains (Ponderosa Pine/Dry Grass) Pinus ponderosa / Pseudoroegneria spicata, Pinus ponderosa / Festuca idahoensis Other vegetative classification: ponderosa pine/Idaho fescue (CN140) Hydric soil rating: No Custom Soil Resource Report 13 Minor Components Marblespring Percent of map unit:10 percent Landform:Outwash terraces Landform position (three-dimensional):Tread Down-slope shape:Linear Across-slope shape:Linear Other vegetative classification:ponderosa pine/bluebunch wheatgrass (CN130) Hydric soil rating: No Hardesty Percent of map unit:5 percent Landform:Drainageways, depressions Landform position (three-dimensional):Tread Down-slope shape:Linear, concave Across-slope shape:Linear, concave Other vegetative classification:ponderosa pine/ninebark (CN190) Hydric soil rating: No Bong Percent of map unit:5 percent Landform:Outwash plains Landform position (three-dimensional):Tread Down-slope shape:Linear Across-slope shape:Linear Other vegetative classification:ponderosa pine/bluebunch wheatgrass (CN130) Hydric soil rating: No Hagen Percent of map unit:5 percent Landform:Outwash terraces Landform position (three-dimensional):Riser Down-slope shape:Linear Across-slope shape:Convex Other vegetative classification:ponderosa pine/common snowberry (CN170) Hydric soil rating: No 7121—Urban land-Marble, disturbed complex, 3 to 8 percent slopes Map Unit Setting National map unit symbol: 2mdn1 Elevation: 1,750 to 2,360 feet Mean annual precipitation: 18 to 20 inches Mean annual air temperature: 45 to 50 degrees F Frost-free period: 100 to 130 days Farmland classification: Not prime farmland Map Unit Composition Urban land:60 percent Custom Soil Resource Report 14 Marble, disturbed, and similar soils:35 percent Minor components:5 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Urban Land Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 8 Hydric soil rating: No Description of Marble, Disturbed Setting Landform:Outwash plains Landform position (three-dimensional):Tread Down-slope shape:Linear Across-slope shape:Linear Parent material:Sandy glaciofluvial deposits Typical profile A - 0 to 4 inches: loamy sand E - 4 to 8 inches: loamy sand E and Bt1 - 8 to 27 inches: sand E and Bt2 - 27 to 53 inches: sand C - 53 to 60 inches: sand Properties and qualities Slope:3 to 8 percent Depth to restrictive feature:More than 80 inches Drainage class:Well drained Capacity of the most limiting layer to transmit water (Ksat):Moderately high to high (0.57 to 1.98 in/hr) Depth to water table:More than 80 inches Frequency of flooding:None Frequency of ponding:None Available water capacity:Very low (about 3.0 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 4s Hydrologic Soil Group: B Ecological site: F043AY509WA - Warm, Xeric, Sandy, Outwash Terraces and Plains (Ponderosa Pine/Dry Grass) Pinus ponderosa / Pseudoroegneria spicata, Pinus ponderosa / Festuca idahoensis Other vegetative classification: ponderosa pine/Idaho fescue (CN140) Hydric soil rating: No Minor Components Hardesty, disturbed Percent of map unit:2 percent Landform:Drainageways, depressions Landform position (three-dimensional):Tread Down-slope shape:Linear, concave Across-slope shape:Linear, concave Other vegetative classification:ponderosa pine/ninebark (CN190) Custom Soil Resource Report 15 Hydric soil rating: No Marblespring, disturbed Percent of map unit:1 percent Landform:Outwash terraces Landform position (three-dimensional):Tread Down-slope shape:Linear Across-slope shape:Linear Other vegetative classification:ponderosa pine/bluebunch wheatgrass (CN130) Hydric soil rating: No Phoebe, disturbed Percent of map unit:1 percent Landform:Outwash plains Landform position (three-dimensional):Tread Down-slope shape:Linear Across-slope shape:Linear Other vegetative classification:ponderosa pine/common snowberry (CN170) Hydric soil rating: No Hagen, disturbed Percent of map unit:1 percent Landform:Outwash terraces Landform position (three-dimensional):Tread Down-slope shape:Linear Across-slope shape:Convex Other vegetative classification:ponderosa pine/common snowberry (CN170) Hydric soil rating: No 7122—Urban land-Marble, disturbed complex, 8 to 15 percent slopes Map Unit Setting National map unit symbol: 2mdnc Elevation: 1,750 to 2,360 feet Mean annual precipitation: 18 to 20 inches Mean annual air temperature: 45 to 50 degrees F Frost-free period: 100 to 130 days Farmland classification: Not prime farmland Map Unit Composition Urban land:60 percent Marble, disturbed, and similar soils:35 percent Minor components:5 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Urban Land Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 8 Custom Soil Resource Report 16 Hydric soil rating: No Description of Marble, Disturbed Setting Landform:Outwash plains Landform position (three-dimensional):Riser Down-slope shape:Linear Across-slope shape:Linear Parent material:Sandy glaciofluvial deposits Typical profile A - 0 to 4 inches: loamy sand E - 4 to 8 inches: loamy sand E and Bt1 - 8 to 27 inches: sand E and Bt2 - 27 to 53 inches: sand C - 53 to 60 inches: sand Properties and qualities Slope:8 to 15 percent Depth to restrictive feature:More than 80 inches Drainage class:Well drained Capacity of the most limiting layer to transmit water (Ksat):Moderately high to high (0.57 to 1.98 in/hr) Depth to water table:More than 80 inches Frequency of flooding:None Frequency of ponding:None Available water capacity:Very low (about 3.0 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 4s Hydrologic Soil Group: B Ecological site: F043AY509WA - Warm, Xeric, Sandy, Outwash Terraces and Plains (Ponderosa Pine/Dry Grass) Pinus ponderosa / Pseudoroegneria spicata, Pinus ponderosa / Festuca idahoensis Other vegetative classification: ponderosa pine/Idaho fescue (CN140) Hydric soil rating: No Minor Components Rock outcrop Percent of map unit:1 percent Hydric soil rating: No Marblespring, disturbed Percent of map unit:1 percent Landform:Outwash terraces Landform position (three-dimensional):Riser Down-slope shape:Linear Across-slope shape:Linear Other vegetative classification:ponderosa pine/bluebunch wheatgrass (CN130) Hydric soil rating: No Bong, moist, disturbed Percent of map unit:1 percent Landform:Outwash plains Landform position (three-dimensional):Riser Custom Soil Resource Report 17 Down-slope shape:Linear Across-slope shape:Linear Other vegetative classification:ponderosa pine/common snowberry (CN170) Hydric soil rating: No Lakespring, disturbed Percent of map unit:1 percent Landform:Outwash plains, terraces Landform position (three-dimensional):Tread Down-slope shape:Linear Across-slope shape:Convex Other vegetative classification:ponderosa pine/ninebark (CN190) Hydric soil rating: No Hardesty, disturbed Percent of map unit:1 percent Landform:Drainageways, depressions Landform position (three-dimensional):Tread Down-slope shape:Linear, concave Across-slope shape:Linear, concave Other vegetative classification:ponderosa pine/ninebark (CN190) Hydric soil rating: No Custom Soil Resource Report 18 References American Association of State Highway and Transportation Officials (AASHTO). 2004. Standard specifications for transportation materials and methods of sampling and testing. 24th edition. American Society for Testing and Materials (ASTM). 2005. Standard classification of soils for engineering purposes. ASTM Standard D2487-00. Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of wetlands and deep-water habitats of the United States. U.S. Fish and Wildlife Service FWS/OBS-79/31. Federal Register. July 13, 1994. Changes in hydric soils of the United States. Federal Register. September 18, 2002. Hydric soils of the United States. Hurt, G.W., and L.M. Vasilas, editors. Version 6.0, 2006. Field indicators of hydric soils in the United States. National Research Council. 1995. Wetlands: Characteristics and boundaries. Soil Survey Division Staff. 1993. Soil survey manual. Soil Conservation Service. U.S. Department of Agriculture Handbook 18. http://www.nrcs.usda.gov/wps/portal/ nrcs/detail/national/soils/?cid=nrcs142p2_054262 Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for making and interpreting soil surveys. 2nd edition. Natural Resources Conservation Service, U.S. Department of Agriculture Handbook 436. http:// www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053577 Soil Survey Staff. 2010. Keys to soil taxonomy. 11th edition. U.S. Department of Agriculture, Natural Resources Conservation Service. http:// www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053580 Tiner, R.W., Jr. 1985. Wetlands of Delaware. U.S. Fish and Wildlife Service and Delaware Department of Natural Resources and Environmental Control, Wetlands Section. United States Army Corps of Engineers, Environmental Laboratory. 1987. Corps of Engineers wetlands delineation manual. Waterways Experiment Station Technical Report Y-87-1. United States Department of Agriculture, Natural Resources Conservation Service. National forestry manual. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/ home/?cid=nrcs142p2_053374 United States Department of Agriculture, Natural Resources Conservation Service. National range and pasture handbook. http://www.nrcs.usda.gov/wps/portal/nrcs/ detail/national/landuse/rangepasture/?cid=stelprdb1043084 19 United States Department of Agriculture, Natural Resources Conservation Service. National soil survey handbook, title 430-VI. http://www.nrcs.usda.gov/wps/portal/ nrcs/detail/soils/scientists/?cid=nrcs142p2_054242 United States Department of Agriculture, Natural Resources Conservation Service. 2006. Land resource regions and major land resource areas of the United States, the Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook 296. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/? cid=nrcs142p2_053624 United States Department of Agriculture, Soil Conservation Service. 1961. Land capability classification. U.S. Department of Agriculture Handbook 210. http:// www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_052290.pdf Custom Soil Resource Report 20