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20050755 Erosion Rpt 03202012° L~JLI~JL~ ENGINEERING, INCORPORATED -~aird ~e~y%ne~t ~i~ofrsr~o~ur/.: I~~urcfr ~:rosion Control Report Windshadow 14920 Berry Valley Drive SE Yelm, Washinyton Parcel Nos. 217242-0000, 2172424-0200, & 2172424-0300 Prepared For American West Bank 4 Nickerson Street Suite 200 Seattle, Niashington 93109 March 20, 2012 BASELINE Job No. OS-104 Prepared by: Jerry A. Waldron, P.E. r., [I ~,a . i e ~nY ll ~, - ~~ ~. i 31~ l iz -~-< L t 4a "l hereby state that Lhis Drainage & EroSiotvSedintznt C ontroi flan tcir [his project has been prepared by me or under nn~ supcrwsimi and meet, dte standani oPcarz and zxpzrttse which is usual and customary in Ihn commmtiry for protesstonal engineers. I undurs:und that Ciq~ of Yclm dues :wt and will not assume iiahi h;ti Par 0,.• :,ul~ici~ncy, suitability. ur performance of drainaee faciliues ;~ren~ rCCi by n,c " In~ r~ \s I yu CS V v ~l ~1 MAR ~ :~ ~Q12 Lend Planning 8 Use Engineering Surveying B~(: _-.--•------------- 1910-64th Avenue West • Tacoma, WA 96466 (253j 565-x491 Fax (253) 565-8563 Seattle (206) 824-1205 "The industry starts here'' 1 ' Table of Contents ' SECTION 1 -PROPOSED PROJECT DESCRIPTION 3 SECTION 2 -CONSTRUCTION SEQUENCE AND PROCEDURE 3 ' SECTION 3 -SOIL STABILIZATION AND SEDIMENT TRAPPING 4 ' SECTION 4 -PERMANENT EROSION CONTROL AND SITE RESTORATION 5 SECTION 5 - GEOTECHNICAL ANALYSIS AND REPORT 5 ' SECTION 6 -INSPECTION SEQUENCE 5 SECTION 7 -CONTROL OF POLLUTANTS OTHER THAN SEDIMENT 5 ' I N 8 T LITIES SECT O -U I 6 ' SECTION 9 -CONCLUSION 6 APPENDIX A -SITE PLAN, SOILS DESCRIPTION, AND FEMA ' APPENDIX B -CALCULATIONS 1 1 1 ~ G' 1 SECTION 1 -PROJECT DESCRIPTION ' The project proposal is to subdivide Parcels 217242-0000, 21724240200, & 21724240300 into 217 residential units composed of single-family residences and townhomes. The project ' site is composed of Soil Type A -Gravelly Sandy Loam and the storm design will utilize underground Low Impact Design BMPs to discharge all runoff generated from the development into the native penneable soils. There is a residential single-family home on-site, which will ' serve as a construction office and will be removed from the site prior to recording of the plat. A public street connected to Tahoma Boulevard to Berry Valley Road. The site is zoned Low Density Residential R-4. ' The 30.2-acre site is located at 14848 SE Berry Valley Rd in Yelm, WA. The subject property is located in the NW quarter of Section 24, Township 17 North, Range 1 East, and W.M. The project will propose a sewer S.T.E.P. system, watermain, storm drainage, and extend dry utilities from Tahoma Boulevard. The project improvements consist of subdividing the parcels into 175 lots for single-family ' residences, 10 open space/storm tract areas, 56-foot right of way dedication for the public road improvements and access to the residences, and 20' wide alley way. All interior streets shall be improved to Yelm City Standards for a Loca/Access Residential, including a 35-foot paved roadway with two 7.5-foot parking lanes, rolled curb and gutter, and a Moot concrete sidewalk on one side. The project will disturb approximately 24.3 Acres where the native soil is classified as Soil Type A. SECTION 2 -EROSION CONTROL SPECIALIST A Certified Professional in Erosion and Sediment Control, Jerry A. Waldron P.E. at Baseline Engineering, 253-565-4491, will be on-call until the contractor can provide an E.C.S. SECTION 3 -EXISTING SITE CONDITIONS The site is composed of two Predevetoped drainage basins where the middle portion of the site is a local depression at elevation 330. Predevetoped Basin 'A' is the northern half of the project site which slopes to the south at grades that range from less than 1 % to 12%. Predevetoped Basin 'B' is the southern half of the project site which slopes to the north at grades that range from less than 1% to 5%. The existing residence and detached barn are located near the southwest portion of the site and will be removed. All storm runoff remains onsite and infiltrates into the existing soils. At the middle portion of the site is an existing water well that currently serves the residences to the west, Parcel Nos. 21724240201 and 21724240202. Peak flows were generated utilizing the WHHM3 continuous storm model. 11. Construct Roadways. 12. Hydroseed exposed soils. 13. Remove erosion control fence, interceptor ditches and catch basin inlet protection after erosion hazards have diminished or site is completely stabilized. 14. Call for final inspection. SECTION 3 -SOIL STABILIZATION AND SEDIMENT TRAPPING Temporary surface water interceptor swales and infiltration will be used to collect surface water flows. Rocked construction entrances will be installed to limit the loss of soil due to vehicles tracking it away from the site. We are encouraging the contractor to clear areas in phases and provide a temporary 10' vegegated buffer along the perimeter of the property. If constructed during the wet season up to five sediment traps will be constructed within the stormlopen space tracts. A sediment trap is not proposed in Developed Basin E since a majority of the site will be undisturbed forested area. Sediment ponds are sized using Waterworks 6.1, 3.5 and the SBUH method calculating peak flows for the 2-year 24-hour storm. See Appendix B for calculations Measures Taken to Control Sediment: 1. A planned construction sequence designed to provide for construction of erosion control features. 2. Gravel construction entrances to mitigate the introduction of sediment into any off-site storm facilities or adjacent public roadway facilities. 3. Installation of a Sediment Pond to dispose stormwater through infiltration if constructed during the dry season. 4. Timely stabilization of exposed soils to prevent erosion. 5. Interceptor swales used to intercept surface water and allow infiltration. 6. Installation of siltation fence as a final level of protection. 7. Silt fences will be utilized to control runoff velocities and sedimentation at appropriate locations on the project site. Interceptor swales will be installed in lowest elevations of the project. 8. Clean sediment from catch basins and the storm conveyance system. 9. The creation of airborne dust during construction will also need to be controlled by the contractor. This can be accomplished through the use of watering trucks during construction. Offsite Cleanup -When construction operations are such that debris from the work is deposited on the streets, the contractor shall, as a minimum, remove on a daily basis any deposits or debris which may accumulate on the roadway surface. Should daily removal be insufficient to keep the streets clean, the contractor shall perform removal operations on a more frequent basis. 4 All of the features contained within the Erosion Control Plan, if installed and periodically maintained, are expected to minimize the level of sediment-laden runoff entering any of the public road right-of-ways and adjacent properties. SECTION 4 -PERMANENT EROSION CONTROL AND SITE RESTORATION Permanent erosion control is provided by asphalt concrete pavement and landscaping exposed or disturbed areas. SECTION 5 - GEOTECHNICAL ANALYSIS AND REPORT The soils have been identified as 110 Spanaway Gravelly, Sandy, Loam which is a Hydrological Soil Group A, using the Soil Conservation Service {SCS) of Thurston County. See Appendix A for soils description. Soil logs will be taken to a depth of at least 3-feet below proposed retention facilities and analyzed at the time of construction of the Infiltration pond to verify the soil type, water table, and infiltration rate used in the preliminary calculations and design. SECTION 6 -INSPECTION SEQUENCE The 'o!Io~,ving structural items will be used to control erosion and sedimentation during c_~nsnartian adivities- • Construction entrance • Filter fabric fences • Sediment Pond • Cover measures (hydroseeding, mulching, plastic cover, netting, free draining material, etc. ) The contractor will identify the Certified Erosion and Sedimentation Control Lead (CESCL) for the project and the CESCL shall inspect the temporary erosion (acilities prior to commencement of construction. During and following construction, the contractor shall inspect the erosion control facilities a minimum of once weekly and after every storm event. If the erosion control facilities are damaged, or if the project engineer or City of Yelm have determined that existing controls are inadequate, the contractor shall install additional measures as required. SECTION 7 -CONTROL OF POLLUTANTS OTHER THAN SEDIMENT The contractor shall be responsible for conlroiling pollutants at the work site. Key elements such as centralized areas for equipment and concrete truck washing and temporary storage of debris and other stockpiled materials are the responsibility of the contractor. 5 The contractor has the option of providing all required material for cover measures on-site at all times or prepare a Plan of Action to submit to City of Yelm. Note that a Plan of Action requires a sediment pond to be designed for the 2-year, 24-hour event. A Plan of Action shall contain the following: • Contractors name, address, phone number, emergency number. • Alfernate contract above information. • Clearly defined plan of action designed to prevent off-site migration of sediments, which will be implemented in the event that a major storm is predicted or off-site erosion is observed by the contractor, his/her employees or the County. • Description of materials to be used for cover and means by which it will be placed. List equipment to be used or number of personnel anticipated to be used to spread material. • Vendor or supplier of materials to be used; Ilst iwo alternatives and include phone numbers. • Means and time frame for cleanup of any materials that escape off-site and for repairs to the natural system, if damages have occurred. The contractor may elect to follow the detailed guidance on control of non-sediment pollutants as outlined in the Best Management Practices in the 1992 DOE Stormwater Management Manual for the Puget Sound Basin. SECTION 8 -UTILITIES During trenching activities, no more than 500 feet of open trench shall be allowed at any time. Excavated material shall be placed on the uphill side of the trench, except where limited by safety or space constraints. SECTION 9 -CONCLUSION Erosion control procedures as described in this report and illustrated on the design plans, if properly implemented, should mitigate anticipated erosion effects from the development of this project. This analysis is based on data and records either supplied to or obtained by Baseline Engineering, Inc. These documents are referenced within the text of the analysis. 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N m Y ~ O 5@ L ~ ~ L ~ ~ ~ 4' j K O 7 C°I N O o U Y O ul ~ tt _ ~ 3 _ g R~ LL U' o ~ W J ~ a Q `m A w n ~ 3 n v _ £ ~ ff ~ ~ ~ 3 g~ a ~}({ 4 ~ O~ ~ U C: t C3 , ~ E F n K in rn in in N N ti O c 6 p O [J' w m ~ ~ n ~^%r w A O 2U Map Unit Legend Thurston County, Waahington (WA067) Map UnR Symbol Map Unit Name ~ Atres lr 74 Nlsqually bamy ling sand. 3 to I S percent ~ slopes 110 Spanwway gmvelfy sandy loam, 0 to 3 ~ perttnt slopes 112 Spwnwway stony sandy loam, Olo3 percent slopP.s 113 Spanav:ay stony sandy bam, 3 to 75 08104-Windshadaw 3.4 12.8% 2.3 6.7% 26.0 Wtunl Rosoumos Web Soll Survey Conservation Sarvlee National CooDaralno Soil Survey Page 3 of 3 OR104-AVindshadow Soil Description Thurston County, Washington 74-Nisqually loamy fine sand, 3 to 15 percent slopes Map Unit Setting • Mean annual precipitation: 40 to GO Inches • Mean annual air temperature: 50 degrees F • Frost-free period: 150 to 200 days Map Unit Composition • Nisqually and similar soils: 85 percent • Minor components: 5 percent Description of Nisqually Setting Landform: Terraces • Parent material: Sandy glacial outwash Properties and qualities • Slope: 3 to 15 percent • Depth to restrictive feature: More than 80 inches Drainage class: Somevahat excessively drained • Capacity of the most limiting layer to transmit water (Ksat): High (1.98 to 5.95 in/hr) • Depth to water table: More than 80 inches • Frequency of flooding: None • Frequency of ponding: None Available water capacity: Low (about 4.9 inches) Interpretive groups • Land capability (nonirrigated): 3e Typical profile • D to 5 inches: Loamy fine sand • 5 to 31 inches: Loamy fine sand • 31 to 6D inches: Loamy sand Minor Components Yelm Percent of map unit: 3 percent os t oa-tivinasl,adow Soil Description Norma Percent of map unit: 2 percent Landform: Depressions 11 ~~ 05104-\Vindshudow Soil llescription Thurston County, Washington 110-Spanaway gravelly sandy loam, 0 to 3 percent slopes Map Unit Setting • Mean annual precipitation: 35 to 65 inches • Mean annual air temperature: 50 degrees F Map Unit Composition • Spanaway anv similar soils: 100 percent Description of Spanaway Setti n g • Landform: Terraces, outwash plains • Parent material: Volcanic ash over gravelly outwash Properties and qualities • Slope: 0 to 3 percent Depth to restrictive feature: More than 80 inches Drainage class: Somewhat excessively drained • Capacity of the most limiting layer to transmit water (Ksat): High (1.98 to 5.95 I n/ h r) • Depth to water table: More than 80 inches • Frequency of flooding: None • Frequencv of ponding: None • Available water capacity: Low (about 3.8 inches) Interpretive groups • Land capability classification (irrigated): 3s • Land capability (nonirrigated): 3s Typical profile • 0 to 15 inches: Gravelly sandy loam • i5 to 20 inches: Very gravelly loam • 20 to 60 inches: Extremely gravelly sand ~~ 03104-«'indvhaduw• Soil Description Thurston County, Washington 112-Spanaway stony sandy loam, 0 to 3 percent slopes Map Unit Setting • Mean annual precipitation: 35 to 65 inches n9ean annual air temperature: 50 degrees F Map Unit Composition • Spanaway and similar soils: 100 percent Description of Spanaway Setting • Landform: Terraces, outwash plains • Parent material: Volcanic ash over gravelly outwash Properties and qualities Slope: 0 to 3 percent • Depth to res[rictive feature: More than 80 inches • Drainage class: Somewhat excessively drained • Capacity of the most limiting layer to transmit water (Ksat): Hlgh (1.98 to S95 in/hr) • Depth to water table: More than 80 inches • Frequency of flooding: None • Frequency of ponding: None • Available water capacity: Low (about 4.0 inches) Interpretive groups • Land capability (nonirrigated): 4s Typical profile • 0 to 16 inches: Stony sandy loam • 16 to 22 inches: Very gravelly sandy loam • 22 to 60 inches: Extremely gravelly sand `.fJ 08104-~i'in~lsliaduw Soil i)escriplion Thurston County, Washington 113-Spanaway stohy sandy loam, 3 to 15 percent slopes Map Unit Setting Mean annual precipitation: 35 to 65 inches • Mean annual air temperature: 50 degrees F Map Unit Composition • Spanaway and similar soils: 100 percent Description of Spanaway Setting • Landform: Terraces, outwash plains Parent material: Volcanic ash over gravelly outwash Properties and qualities • Slope: 3 to 15 percent Depth to restrictive feature: More than 80 inches • Drainage class: Somewhat excessively drained • Capacity of the most limiting Layer to transmit water (Ksaf): High (1.98 to 5.95 in/hr) • Depth to water table: More than 80 inches • Frequency of flooding: None • Frequency of ponding: None • Available water capacity: Low (about 4.0 inches) Interpretive groups Land capability (nonirrigated): 4s Typical profile • 0 to 16 inches: Stony sandy loam • 16 to 22 inches: Very gravelly sandy loam • 22 to 60 inches: Extremely gravelly sand l~ 1 yea W w r ~e a. a u cu_u e ~ s _ °. mw "n ~ 98F~ O : ~ ~ ~ ~ C 0 ~ v Y•~• ~ Y s r' ~ ~ 'zo o - E Y~'~o J s Q ~T" < ~ ~ m ~ C § L ~' N 4 ~ IC c ~ =m yw/m ~ 3 5~~~~ ° " N S C7 = +E„ V O e~ m. yn 1fi W 'mow W 55 Y ~ ~ F ~$~g F- v Q ~. ~"~ ~ s ~ o S a -- f o 9 ~ ~ m ~ °S = ` F~~Ei ` X O °. c Z ~ ~ C EiZ.~ r O ~ qf~/J 2 ~n w~s i ~ .-a 9 o Z Z a w _ Tp ~ $- u~ 4~u ~~~~ 6a~ S•^ ~ O m y ~ nY ~ ~ - - _ _~= -== t =m s ~`~-a_ $ I °_- ~_ -- - -- ~ E a5 ~B~LLF a YE ~ee !J~°P an s p of ~30~¢ ~ • !-o W o ~\ _OW ~ c Zo R VALIEY __ D I ` ~~ 8 ~ O ~uu 3."wJ r ~ • ~ o 0 O H ar ~ I ~ m ~~ ~ ~N 0 ~ ~: ~, ` . \\ \ ° u \\ ~ . _. __ o ___ ___ _ ___- -~ ~_- `1 I ri•° _ - q 0 11 ~~ ° ; I` o ~~ y II ~ o ~ ~~ Q F ~, ° QE Hx~ 11 ~~ Z O ~ t7 V o a o u 1\ !I N w U H Y -' > : C;~ r /i 7 W Z Q ~ O a O N W 6 Q y v ~ ~' °' c N LL a z E ~! \ • O a§ a ~. ` -.. < ~ 'Q r \ W A $ ` J W Z ` I ~ \~ ` I~ ( APPENDIX B CALCULATIONS 1 ~ ~~ Ih~Q~SQ~l~11 I 60186 'VM '31L1V36 OOZ 3Lf1S '133kiLS NOSli3)IOIN 4 d'dHl 1N3WI03S - OS31 3.57'6 Will ~NV6 ONINI~ 1 )i rye :::>bne -.. ,, N N W Yy{ ~ V ++ a .+ < n R a g y~ ~ K F o ° `cCR ~ y d a u+ ^i ¢1 ~i [1 < R Uy G L V G ~ 4 2 < Lt' J c S S O 9 !I1 RI p} i 3 ¢~ g O ~3 ~ Jz~[ 2 N Y z~~ P n }•~ v»¢s r. •ow«ei . yrv .n...v wa-owi I +r - v~ir..n¢ ¢.u.w¢>p •.n • vq.nbi. wa 1, 76DC- tva¢-ao: «:7 >YI • Vu[~-+CY¢Ei) >Pws • 1e>.-si-rltu) .~..,._.. ~...~r.. - -~---~--- - -l~rm JNI '~NIa33Nl'JN3 ~.~~i°.~~- <1 ~r;~f ~ ~ ~~ I 0 '~~~ . ~! ; _ ~ ~ ~ NHCOOj'4F(5.f.7~1 ,£?'f-l4l~O~'GOe~'4 8i~:0~7. i10U9Zig Wnp-7S?~-~i SLOW ~6u 1f+J! f9C 50pf900Z1~ Wa&tYioAa HMS Roport rrWay. Jufy 20, 2011 Project CCrnayance Papa 1 08104Windshadow SBUH Conveyance Storm Drainage Calculations Developed Basin A Project Precips [2 yr) 2.00 in (5 yrJ 2.50 in (10 yr] 3.00 in (25 yr] 3.50 in [100 yr] 4.00 in [6 moj 1.28 in Drainage Aroa: Dev-A Hyd Method- SBUH Hyd Loss Method: SCS CN Number Peak Factor: 484.00 SCS Abs: 0.20 Storm Dur 24.00 hrs Area CN TC Pervious 0.4230 ac 50.00 0.16 hrs Impervious 0.2190 ac 98.00 0.02 hrs Total 0.6420 ac Supporting Data: Pervious CN Data: Landscaping Type A -Soils 50.00 0.4230 ac Impervious CN Data: 37' road + 5' SW 98.00 0.2190 ac Parvbus TC Data: Fk>.v type: Description: Length: Sbpe: Coati: Travel Time Stleet flow down larxfsgping SO 00 ft 1.00% 0.1 S00 9.39 min hnpervtous TC Data: Flow type: Descriptlon: Length Slope: CoefF Travel Time Sheet road to CB 18.00 ft 2.00% 0.0110 0.39 min Channel storm pipe 220.00 ft 1.00% 42.0000 0.87 min TC of 1.26 min < 5 min, program wlll use a lc of 5 min In computations. 100 yr Flow Time Vdume Summary. 0.2148 cis 7.83 hrs 3505 35 cf - 0.0805 acfl BasinlD Peak Q Peak T Peak Vd Area Method Raintype Event - (~) (~) (ac-ft) ac /Loss Dev-A 0.08 7.83 0.0194 0.64 SBUHlSCS TYPEIA 6 mo Dev-A 0,10 7.83 0.0324 0.64 SBUH/SCS TYPEIA 2 yr Dev-A 0,19 7.83 0.0665 0.64 SBUH/SCS TYPEIA 25 yr Dev-A 0.21 7.83 0.0805 0.64 SBUH/SCS TYPEIA 100 yr 2~ Project Name: Windshadow Uatc: 8/1 5120 7 7 Le znd: ProjectlYumber: US-104 entryspacc Sediment Pond (Pierce Counh• Stt[ndard) constants design values Given: Developed 'A' remarks Q. (2-yr, 24 hr): O.lOU cfs Qu>(10-}~, 24l><): O.l-5~ cfs Qmo(100-yr, 24 hr): 0.210 efs Soil Typc: a ITeight of riser (h): 3 ft Height ufeutet'gency nver!)oa• walcrsurfaCe (I3): 11.3 R use between 0.3 and 0.$ Plan of Aclion for LSC control mzysures? n uk Uewatzring time ('f); 24 hrs Gravity wustaat (c); 32.2 IL'szc^2 Se[tling vebcity (Vs): 0.0018 IL'scc Safety factor (FS): 2.0 Itcquired Design Parameters: Surface arts (As): l I I syf keq'd measured at weir invert .4s = FS*/OiVsJ Q: for no plmt njarri0n & 7:e jut Tun oJ'acrinrt Oritcz area (Ao): 0.0001 syC A0 = (:4s(?h/`~`J. j`(JQb*.ib00"T*~"0.5) Orifice dismcler f U); O.10 inches Lcngdt of bonom wzir for emergency overflow (L): ©ft use 6 feet L = (Q wn/(3.21'H^(3/2JJ)-2.4'H^2 Ossed ou Surface Area Provided: 120 s Uewaterine Orilice Surfsce.4rea provided' 120 syf OK -Lr = FS*/[J`6's} O: jnr nn plan 0f action & O n, br pJmt of acaion Orifice area: 0.0001 sqf .40 = /,4!'(3h}^~ S},{)IJ. b "Jbfiq*T"g"O. S i Onticc diameter: 0.10 inches Use 1" Orifice D- 24'(.40%3.)~l^OS a ~- WaleNJOrks HMS Report Friday, July 29. 2011 P oct: Conve ante p ° 2 08104-Windshadow SBUH Conveyance Storm Drainage Calculations Developed Basin B Project Precips [2 yr] 2.00 in [5 yr] 2.50 in [10 yr] 3.00 in [25 yrJ 3.50 in [100 yr] 4.00 in [6 mo) 1.28 in Drainage Area: Dev-8 Hyd Method: SBUH Hyd Loss Method: SCS CN Number Peak Factor: 484.00 SCS Abs: 0.20 Storm Dur 24.00 hrs Area CN TC Pervious 3.4190 ac 50.00 0.16 hrs Impervious 1.0880 ac 98.00 0.08 hrs Total 4.5070 ac Supporting Data: Pervious CN Data: Landscaping-Type A Soils 50.00 3.4190 ac impervious CfY Data: 37' road + 5' SW 98.00 1.0880 ac Pervious TC Data: Flew type- Description: Length: Sbpe: Coeff: Travel Time Sheet flow down landscap ing 50.00 ft 1.00% 0.1500 9.39 min Impervious TC Data: Flow type: Description: Length: Slope: Coeff Travel Time Sheet road to CB 18.00 fi 2.00% 0.0110 0.39 min Channel storm pipe 1046.00 ft 1.00% 42.0000 4.15 min TC of 4.54 min < 5 min, program will use a tc of 5 min in computatigns. 100 yr Flow Tlme Volume Summary: 1.0063 cfs 7.83 hrs 19006.31 cf - 0.4363 acft BasinlD Peak Q Peak T Peak Vol Area Method Rainrype Event --- (cfs) (hrs) (ac-ft) ac !Loss Dev-B 0.29 8.00 0.0965 4.51 SBUH/SCS TYPEIA 6 mo Dev-B 0.48 7.$3 0.1609 4.51 SBUH/SCS TYPEIA 2 yr Dev-B 0.88 7.$3 0.3519 4.51 SBUH/SCS TYPEIA 25 yr Dev-B 1.01 7.83 0.4363 4.51 SBUH/SCS 7YPE1A 100 yr 7_ 3 Project Name: R'inrlshsdow Date: Si 15r'209 4 Le cud: Project t\umbcr: U8-104 entry space Sediment Yond (Pierce County Standard) constants design values Givco: Developed '6' remarks Qz (2-yc 24 hr): OARO cfs Q:o(10-yr, za hr): 0.74; cfs Q:o,(100-yr, 246r): LOlO cis Soil Type: a Height of riser (h); 3 ft Height of emergency overflow water surface (II): U.3 ft use bahveen 0.3 and 0.5 Plan of action for ESC control measures' n nk Dewatzring time {"[~: 24 hrs Gravity constant (g): 32.2 fVSec^2 Sztttingvelociq•(Vs): O.OOIR fusee Safety factor (1''S): 2.0 Required Ucsign Parameters: Surface area (.4s): >33 sqf Req'd measured at weir invert As = Fb'*(~h'Vsj Q r fir nu plan ol:r~tion B O.a fur tan ojuctiar Orifice area (.Ao): 0.0Otl3 sqf ,4n = (~4s(2nJ^~. 5,t'(10.6*3600'T',y'0. ~i Orifice diameter (D): 0.21 inches Lcngdt of bottom weir for emergency overflow (L): ©ff use 6 feet L = (D :a~/(3.21'H^(3/2)))-2.4'H^2 Based on Surfacr Area Prot~ded: 575 s Dewaterina Orifice Sttrtacz Arca provided: i7j sqf OK $=hS°l Qi l:r) QrJ•9r ro p/rrx ufaclioro c f J;~~ft~. I:erz r;frrttinn Orifice area: 0.000) sqf An = (Asl2h1^QSj/I10.6*3600*T'g^0.>j Orifice diameter. 0.22 inches USe 1" Orifice ~~ WaterWOrKS HMS Report Fdday, July 29, 2011 Pmiect: Conveyance Page 3 08104-Windshadow SBUH Conveyance Storm Drainage Calculations Developed Basin C Project Precips [2 yr] 2,00 in [5 yr] 2,50 in (10 yr] 3.00 in (25 yr] 3.50 in [100 yr] 4.00 in (6 mo] 1.28 in Drainage Area: Dev-C Hyd Method: SBUH Hyd Loss Method: SCS CN Number Peak Factor: 484.OD SCS Abs: 0.20 Storm Dur 24.00 hrs Area CN TC Pervious 5.5910 ac 50.00 0.16 hrs Impervious 1.3690 ac 98.00 0.09 hrs Total 6.9600 ac Supporting Data: Pervious CN Data: Landscaping-Type A Soiis 50.00 5.5910 ac Impervious CN Data: 37' road + 5' SW 98.00 1.3690 ac Pervious TC Data: Flow type: Description: Length: Slope: Cceff: Travel Time Sheet flow down landscapi ng 50.60 ft 1.00% 0.1500 9.39 min Impervious TC Data: Flow type: Description: Length: Slope: Cceff: Travel Time Sheet road to CB 18.00 ft 2.00% 0.0110 0.39 min Channel storm pipe 1281.00 ft 1.00% 42.0000 5.08 min 100 yr Flow Time Volume Summary: 1.2507 ctS 8.00 hrs 25472.93 cf - 0.5848 acft BasinlD Peak Q Peak T Peak Vol Area Method Raintype Event - (cfs) (hrs) (ao-ft) ac /Loss Dev-C 0.37 8.00 0.1214 6.96 SBUH/SCS TYPEtA 6 mo Dev-C 0.60 8.00 0.2024 6.96 SBUH/SCS TYPEIA 2 yr Dev-C 1.09 8.00 0.4638 6.96 SBUH/SCS TYPE1A 25 yr Dev-C 1.25 8.00 0.5848 6.96 SBUH/SCS TYPEIA 100 yr -, i ,~ `_, Project \ame: R'indshadoa• Uate: 8!15!2011 LcQend: Project \ umber: OR-104 entry spice Sediment Pond (Pierce County Standard) constants design values Given: Developed 'C' remarks ~' (2-yr, 24 hr): O.GUO cfc Qxi(10-yT, 24 hr): i)_92? cfs Qi~c(]00-yr, 24 hr): 1.2i0 cfs Soil T,'pc: a Height ofriser (h}: 3 ft Heigh) ofcmergency overflow water surface IH>: 0.3 It use between 0.3 end 0.5 Plan o[ Action for ESC control measuredi! n ok Dewstcriog torte (T) 24 hrs Gravity consrtrtt (g): 32.2 fJsec^2 Settling velocity (Vs): 0.0018 fdsec D'afery factor (h S}: 2.4 Reyuircd llesi>;n Parameters: Surface area (As): GG~ syf Rey'd measured at weir invert As = FS*(Q~`Vsj ~J: fur no plan gJ'artimt & .u fur +lan of ar.•tioa Orifice area (Ao): 0.0003 syf Ao =/.~ (2hJ^O..iJ/(T (1.6 *?600 *T*g''0. S/ Orifice diameter (U): 0.23 inches U = 24'(.9013.14)"0.5 Length of bottom weir for emergency overflow (L): 6 fl use G leer L = (O +co/(3.21"H^(3/2)J)-2.4"N^2 Based oo Surface urea Provided: 675 sit f Dc~raterine Orilice Sttrface Area provided: GiS syf OK As = !'S*(~j) `Y.tj Q ~ far +to plan 0f ac'ion & Q:a or plan n% acriun Orifice area: 0.0001 sqf .40 = lAs(?hl^0.5J/(I0.6* 360(1 *T*y^u, 51 Orifice diameter: 0.24 inches Use 1" Orifice ~~ VJaterWorks HMS Report Friday, July 29.2011 Pro ect: Conveyance Pa e 5 08104Windshadow SBUH Conveyance Storm Drainage Calculations Developed Basin E Project Precips (2 yr] 2.00 in [5 yr] 2.50 in [10 yr] 3.00 in 125 yr) 3.50 in (100 yr] 4.OD in (6 mo) 1.28 in Drainage Area: Dev-E Hyd Method: SBUH Hyd Loss Method: SCS CN Number Peak Factor: 484.00 SCS Abs: 0.20 Storm Dur 24.00 hrs Area CN TC Pervious 6.1660 ac 50.00 0.16 hrs Impervious 1.1960 ac 98.00 0.08 hrs Total 7.3620 ac Supporting Data: Pervious CN Data: Landscaping-Type A Soils 50.00 6.1660 ac Impervious CN Data: 3T road + 5' SW 98.00 1.1960 ac Pervious TC Data: Flow type: Description: Length: Slope: Cceff: Travel Time Sheet flow down landscapi ng 50.00 ft 1.00% 0.1500 9.39 min impervious TC Data: Flow type: Description: Length: Slope: Coeff: Travel Time Sheet road to CB 18.00 ft 2.00% 0.0110 0.39 min Channel storm pipe 1080.00 ft 1.00% 42.0000 4.29 min 7C o£ 4.57 min ~ 5 m„n, program wi!! use a tc of 5 min in camputalions. 100 yr Flow Time Volume Summary: 1.1015 cfs 7.83 hrs 23805.15 cf - 0.5465 acft BasinlD Peak Q Peak T Peak Vol Area Method 12aintype Event -- (cfs) (hrs) (acft) ac /Loss qev-E 0.32 8.00 0 1060 7.36 SBUHISCS TYPEIA 6 mo qev-E 0.53 7.83 0.1768 7.36 SBUHISCS TYPEIA 2 yr qev-E 0.96 7.83 0.4261 7.36 SBUHISCS TYPEIA 25 yr Dev-E 1.10 7.83 0.5465 7.36 SBUHISCS TYPE1q 100 yr 7 Project Name: ~~'indshadow Date: 811 512 0 1 1 Le end: Project Number: OR-104 entry space Sedimcur Pond (Pierce County Sraudard) constants design values <;iven: Developed 'F:' remarks Q: (2-yr, 24 6r): 0.530 cf's Qio(10-yr, 24hr): (1.915 cfs Qi~{100-yr, 24 hry: I.I00 cfs Soil Typc: a Height of ri;er(h): 3 h Height n1' cmcrgcnc}• overflow water surface ({{) 0.3 iT use betv,~een U.3 and 0.5 Plan of Ac[ion fnr F.SC contrul measures? n ok Dewatcring ume (I'): 24 hr; Gravin~constant(g): 32.2 ftser"2 Settling velocity (Vsl: 0.001$ fVscc Safety factor (FS): 2.U Required Uesl~n Parameters: Surface area (ASI: 589 sqf Req'd measured at weir invert As ° F.S'((1.-'VsJ O: for no plurs oJ'uction & Q_ ~a br plan of action Orifice area (:10): 0.0003 ;qf Ao = (9s(2h)^D.5)!(I R 6'T3bfi0'T•~'0. ?) Orifice diameter (U): 0.23 inches p = 24 "(Ao/3.141 ^Q 5 Leng[6 ofAottnm weir fur cmr_rgcncy overflow (L): Oft use 6 I'ect L = (O mu/(3.21'H^(3/2)))-2.4'N^2 Rased on Surface Area Provided: 625 sJt f Dewa[erine Orifice Surface .4re:+ provided: fi2S ;qf OK :1s = FS"(U/V~J Q: Jor no plan ojaction Rc Q:~~ tar .larr ufactiors Orifice arcs: O.C1003 sql' Au _ (As(2hi'Y1.51.~(JO.G"3600*T",~^p.51 Orifice diameter: 0.23 urches Use 1" Orifice IJ = ?4"(Aa%3.14)^0.5 ~-r U Waterworks HMS Report ' Friday. July 29.2071 ed: Conve ance Pro Pa e 6 08104Windshadow SBUH Conveyance Storm Drainage Calculations Developed Basin F Project Precips (2 yrj 2.00 in [5 yr] 2.50 in [10 yrJ 3.00 in [25 yr] 3.50 in [700 yr] 4.00 in [& ma) 1.28 in Drainage Area: Dev-F Hyd Method: SBUH Hyd Loss Method: SCS CN Number Peak Factor: 484.00 SCS Abs: 0.20 Storm Dur 24.00 hrs Area CN TC Pervious 6.3160 ac 50.00 0.16 hrs Impervious 1.9130 ac 98.00 0.11 hrs Total 8.2290 ac Supporting Data: Pervious CN Data: Landscaping-Type A Soils 50.00 6.3160 ac Impervious CN Data: 3T road + 5' SW 98.00 1.9130 ac Pervious TC Data: Flow type: Description: Length: Slope: Cceft: Travel Time Sheet flow down landscaping 50.00 ft 1.00% 0.1500 9.3g min Impervious TC Data: Flow type: Description: Length: Slope: Coeff: Travel Time Sheet road to CB 18.00 ft 2.00% 0.0110 0.39 min Channel storm pipe 1560.00 ft 1.t109'o 42.0000 6.19 rnirr 100 yr Flow Time Volume Summary: 1.7367 cfs 8.00 hrs 33784.67 cf - 0.7756 acft BasInID Peak Q Peak T Peak Vol Area Method Raintype Event -- (cfs) (hrs) (ac-ft) ac /Loss Dev-F 0.51 8.00 _ 0.1696 8.23 SBUHlSCS TYPEIA 6 mo Dev-F 0.84 8.00 0.2826 8.23 SBUHlSCS TYPEIA 2 yr Dev-F 1.51 8.00 0.6237 8.23 SBUH/SCS TYPEIA 25 yr Dev-F 1.74 8.00 0.7756 8.23 SBUHISCS TYPEIA 100 yr I Project Name: R'indshadow Date: 817512011 Le end: Project Number: 08-I l)4 entry space ~cdiment Pund (Yicrcz County Standard) constants design values Given: Uecclopzd 'F' remarks Qz (2-yr, 24 hr): 0.840 cfs Q:o(10-yr, 2d hrl: 1.290 cYs Qa~~,(100-yr. 241u'1: I.?40 cfs Soi! 'T yl.'e: a Height of riszr Qt); 3 ft height ol'cmzrgency overllo+^ wafer surface (H) 0.3 ft use beta~ecn 0.3 and O.S Plan of Action tirr LSC control measures? n ok Dewulcring time (T): 24 hrs Gravity constant (g): 32.2 fdsec^2 Settling vzlocin (Vs): O.OOIB fusee Safety lactor (ES): 2.0 Required Design Parameters: Surface area (As): 933 syl" Req'd measured at wzir invert ds = FS`(Q/VsJ Q: fnr n0 plan ofn clinn & );a 0r' Imt of nctinn Orifice area (Ao): O.000a sqf Ao - lA,c{2hj^0.?j/(1t).6~3600"Tg^0.S) (hifice diamerer (D): 0.28 incl[zs Length of bottom u~zir for emergency avzrflow (L). ~-~ L_ `Jft use 6 fee[ L = (O roc/{3.21'H^(3/2J))-2.4'H^2 13aszd on lurface .4rca Provided: 9&t) s~f Dewaterint[ Orifice Surface Area provided: 960 sqf OK .4s =l~S'r(QN,aJ O> for nn plan nfac tiun & Q,~ Jm~ ~Lvr ofaati0n Orifice area: 0.0005 gq l' AO = (A.r(Zhj'^0_~i/(10.6".3h00°!"g^0.51 Orifice diameter 0.29 inches Use 1" Orifice U = 24'!.40,-?. ! 4/ "ll. ~~~ L Conveyance Capaclly Developed Storage Area Conveyance Capacity Check 08104Windsahdow MANNING'S EQUATION FOR OPEN CHANNEL FLOW CIRCULAR PIPE CAPACITY I 12" Storm Pipe @ 0.5% 1.49~1R' S 2 SBUH Analysis Q= n Input Values d =diameter of pipo 1.OU ff h = hei ht of flow 0:90 ff S = lon itudinal sloe 0.0050 fU'ft n = rou hness coefficient 0.013 V =Velocity 3.62 fps A =Area P =Perimeter WA =Wetted Area 0.745 ftz W P =Wetted Perimeter 2.498 ft R = H draulic Radlus 0.298 ft Percent Full 90.0 Q = Quanti of flow 2.69 cfs > 2 fps for cleansing velocity 0100-yr = 1.74 cfs Developed F Basin Capacity Check for 100-vr storm 24-hr Storm Qpepe > Q100•yr 2,8g cfs > 1.74 cfs =_> MeelssaDacity PipeCapacity.xls Baseline Engineering, Inc. (JAW)