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PE-1885 PRAIRIE ORCHARD DRAINAGE REVIEW FINAL REPORT
CLC A55OCIATES Q E N V E R 5 P 0 K A?J E SALT LAKE CITY . Ic . ?&u"ri sep+ Sot 2 co z. Sv~b nn 4 z ii i i i~ . ~I i , . [3RAINAGE REPi7RT ~ for Prairie iDrchard I i_ ~ i~ i~ ~ Df~~~NAGE REPORT i' for , - Prairie C]rchard S,pQkane Cvunty, Washington September 2002 CLC Jfl6 #S020150 Fpla gn irmi,~raVerraents sE~vwn in fhis se t af paans a~ad calculativns canform tv the e ediEi~ons of the 5pvkar~e Cvunty Standards far Raaci and Sewer tir~n and the Spakane Cour~ty Guidelines fvr 5tarm Water Mar~agement. All e►~iatians have been apprvved by the 5pokane Gvunty Engineer. I approve ns {calculativns} fvr constructian. This report has been prepared by the stafF vf CLC Associates, I nc. u nder the direction vf the undersigned prvfessianal engineer whase seal and signature appear hereon. f3avad Randall, P.E. Phr41RlE C)RCHARf? afiAllVA+GF IVARRe4 Tl1IF GENERAL -This protect is c+n the Prairie ❑rchard prelimmary plat. The site has an existing residential hame an lat 7. The remainder af the sete is vacant with 6ieCd grass as the predominant land cover and Vegetation. The prvject site is lacated on the narth side vf 24`h Avenue between Adams Raad - and Progress Rvad in Spokane County, Washmgtvn. - PIJRPOSE ; The purpose of fhis repart %s to determine, the extertt af starm drainage facifities which wili be required to dispose of fhe increase irr stormwater runofF created by the development of the Prairie Qrchard plat. The storrr drainage facilities an this praject have been desigrted to dispose ' of runvfF fram a ten-year design starm, as required by the Spvkane Caunty Guidelines far 5tarmwafer Managemen#, (GSM). Caiculations are also included to illustrafe the ex#ent of containment for the 10- and 50-year stvrm evenfs. This development es within the Aquiter Sensitive Area of Spokane Caunty and is therefare subject to `208' requiremenls. Far this prvject, the 1 0- and 50-year intensFty curves from the 5pakane, nlledir,al Lake, Reardon, Cheney, and Rackfvrd areas were used, as well as the 5CS , isv-pluvial rairr#all curves. - ANALYSIS A9ETFIC}[3(3LaGY - Per the GSM, the Rational Mefhod, which is recommended far basins less than ten acres in , size, was used to determine the peak drscharges and runoff vofumes for all onsr#e basins. PR!)JECT [3ESC1?IPTlOlll ' The Prairie C3rchard plat is a 2.34-acre develvpment vf 7single-farniiy residential lofs. Prairue ' archard i5 Cocated in 5ection 26, T. 25N., R. 44 E., W.M. within 5pokane Caunry, Wasfaington. TC]POGRAPHY The site generally dratns to fihe southeast at slvpes ranging frvrn 0 to 15 percent. The Northwest corner of the site is ex#rernely flat and generally cirairrs to the norCh-northwest at s9apes rander 2 percent. The runaff frvm this narthwesterly porkion aF the site w►ifE be canveyed to a proposed pond on Lot 3of the F'rairie Qrchard final plat. The runoff from the remainder of the project wiA be conveyed to a propased pond vn Lot 7 of the Prairie Orchard final plat. I~ SQILS As can be seen frvm the accvmpanying soils map from the Spvkane County Soils Survey as per#ormed by the Soil Conservatian Service (SCS), the site cansists of sails with the CEass B type The soi6 type is described as fvlCows: CLC Asscaciates, Ine. 1 Prairie 47rchard i i i GmB -+Garrison very gravelly laam, Q tv 8 percerri' slopes: Sails within this type are - sc+mewhat excessively drained svils fvrmed in grave6y glaeial gutwash material fram a variety of , igneous rock. Surface runoff is medEUm, artd svii holds less then 5 inches vf water thak plarats ean use. GSM indreate this to be a Svil Growp Yype 6 and pre=apprvr+ett fvr doywell , instaflation. []RA1N.4GE NARRATIYL OffSltf' _ Based upan the generaf geagraphrc tendencies surrvunding this site, n❑ offsite f[ows are ' expected. Onsite Alf runoff within the drainage basin will be collected and treated using khe '208' runoff methad as cfescribed in the GSM. Frvm high points in the proposed road improvements, designed En1et Ivcatians and the assumed Eot grading, the propvsed Prairie archard plat was divided intv five aasins (1, 2, 3, 4, anc4 5). 6asin inforrnativn is provaded in Table 1. The cvntributing runoff fram ihe irnpervious street area is designed tv flow to dovunstream ponds by placement vf curb inlets, which divert runoff inta the grassy '208° ponds for treatmerrt. The runoff from each basin is directed to pvnds wi#hin the p[at, weth the exception of Basin 4. , Develaping Basin 4 rsduces the runoff cvefficient from 0.32 to 0.23. The runoff from Basin 4 wilE not be directed into ponds hecause crf the decrease in runofF. The drainage basins and pvnds are shown vn the basin rnap at the back of this report. Tab7e No. °I - Runoff Coetficient 5ummary , ' wLA '.~ti ~}I' a.. i~~ ' ~I.: 2....%q~a ^~a - ; • - , _ ' . :•2`~'x'7~~ ~ k"'q~ ~"~+''~'~~7 , - , o~.lil~`ii~:n` - ~ s,,~ ~;~~~,7ota~~►~e f ~7vta~l'lrriperr►io,iisn' , ~unoffrC. f~x ~z. ~ `"r~ -r y ~ [SFJAC1 -°C l ~ .1 I 53,81411.24 I 16,950 I .39 2 I 19,49810.45 I 7,500 I .44 3 ~ 31,438110.71 ~ 6,200 ~ .30 " 4 I 20,7511[].48 I 2,200 ~ .23 5 I 6,457I0.15 I 6,457 ~ .90 Cvmbined 2 and 5 22,51 QfD.52 I 10,512 ~ .5€1 - Cambined 3 and 5 34,483J9.79 I 9,645 .36 "Tata! Irnpervious Area included paved roadway area, 1,400 s.f per rvvf, and 60[} s.f. per cfriveway, pond, and , sidewalk areas. ~ gC" (irnperviflus area) _ .90 "C" (landscape area) = .15 i i CLC Associates, Inc. 2 ' Prairis Orchard I i ~ Drainage Calculativns Summary Bowstring calculatiarts have been bncluded for individual basiras to deterrnine the extent of storm drainage facilities requrred for the 10-year storm event, Weighted "G" F2C1fiC1ff GQeffIcf8fft5 WBfe calcula#ed for each basin of less than 10 acres as required by lhe Spokane Gounty Guidelr'nes fvr Starmwater Management. TabEe 1 provides the hasin 5ize, tvtal irnpervaaus areas, and - runofF ceefficien#s. _ Provided storage volumes shvwn in the bawstring calculations were determined using the pvnd bvttam areas, 3:1 side s9opes and a one-foat depth. `208' Ca1C[IlatlorlS The '2U8' storage valume fvr each basin was designed to adequately cvntain tne nanoff created by the first haif-inch af rairafall upon the street impecvivus areas within the basin it serves. The , pravided pflnd bottQrn areas, alorrg with a water quality treatment to a depth of eight inches with 3;1 side slopes, provide the total vvlume shown Table 2 summarizes the requirements and de51gnS Q~ the p❑f1dS by ba51n. - 7ahle 2-`208' Area anri Volume Summarty . • `2~8' A•' a208' Pvn~d - Pond ' _ ' '~Basinl , irnperviaus `208' Vvltir~ne `208"Volume . Area RrnVided P~rimete'r: = A`rea (SF)y, , Required_l[CFy. , Pro►ri~ed {CF}L~ `45Fy t , Prn►►ided~L'F), 3,51A 5,120 213 f 284 340 ~ 83.8 1lB 12,000 500 583 750 119.7 ' ~ 2,5/1.r I 6'220 ~ 259 I 277 I 340 ~ 74 - - - - - . -%`208' impervious area consists af street area and driveways at f00SF - per dri►reway. Tvlal Stormwafer Storage Calculatians - !n addition #o the '208' starage requiremenfs, the tv#al sformwater storage for the 10-year design stomn was also considered. Each of the pond5 in P'rairie i]rchard will have the capacity to contaira the required voiume of t'he 10-year design storm. In additian, the 50-year design storm was also examined to verifjr that the 50-year event could be stored in #he pand as designed. This informatran is summarized in Table 3. ' CLC Associates, Pnc 3 Prairze Orchard I Table 3- Stvrmwater Starage Vvlume Surnmary _ . ; _ _ - - _ . - - y'.'' r e Volume-5urnmai ~I 0-year and 50-year StaW`ag r - r . , . - v _ ~.k . . _ ~ _ • . , - - _ _ - -~s='-'_„ 16-_ e~ I ' - k 5 0__ i~ ~..i~ "V V I U ~ e ' • : ' -year►~vlurr~e ~Y pand-~JoEtirne vf Dr•.y~well`s=~ Basin Pvnd - R'equired~{C~~, ' A- - . . -~~quired ~CF~ _F'r'vVided~, 4CF~ . __Regu,~r,~ed~~ ~ - , _ - . 1 6 313 590 930 1 double 2 and 5A C None Required ~ 301 451 EVone 3 and 5B p 64 231 456 'i dauble AValums Prowided is based ❑n 31 side sfapes and 1' depth; (Area)(1') t(Perimeter){1.5W} - g Vvlume is provided by Pand A INLET cALcuLArroNs Inlet calcuQatians wece perfvrrrqed in generak accordanee GSNI and 11}JJ.S D.Q.T. Hydraulic ' ManuaC ta determine the runoffi received and by-pass fl4ws for each inlet. 'By-pass flows calculated for tMe inlets on cantinuous grades were added to the following downgrade inlet. The analysis sFtvws that pcsnd 'A' requides Qne 5' #ype 1 curb inlet, and one 12' type 1 curb inlet. , i Rvnd `C' requires two 6' tYpe 1 curb inPets and Pond `8' requires vne 4' tYpe 1 curb anlet, which is under sump canditians. - FLooaEn vvIarN caLCuLa rrvrvs A diagram has been attached to the Appendix of fhis repor# depicting the worst case for the floaded vvidth caPcuPations. The 50-year sfarm pTVduced a flaoded width of 7.6 Feet adjacent tv Pvnd F1_ CDNCLUSION - As demanstrated by the calcuEativns and body af this report, the storm d'rainage facilities _ provided in this design wiEl adequately remvVe frvm the stree#s, stvre and dispose af the stvrmwater frvrn the site for the 10-year design starm as required by Spvkane Cvurrty. Calcufation worksheets for the 50-year storm event have been pravided tv evaluate the perfarrnance af the designed drainage facilities. Additivnally, the required `208' treatment area is prvaided for the runnff frorn the street impervious areas. _ CLC Rssaciafes, Irtc, 4 Prairie Orchard APPENDIX MAPS vicinity Map 5oifs Map DEVELOPEQ BpWSTRING CALCULATIE?NS 1 aRYear Design Storm 50-Year 5torm Evenf Inlet Calculations Flooded Width CaIculations BA51N MAI' ' ` m Nnrthsvasl mep Sernca 'l --Z' C uxs 6L x A - CoLUNs noux ~ :EL... CpGLIu wii ~'IN VEFIC R m nc VEACLEk YEYERCL~H Ra ~ ~.,~~j ~ Tr~CO e JAi:e Z tira hR4iHiA Q 4 ' I S'l V i p{ p I OAOUwN 4~+ r y■ F ~ WfQ9;Qj5j r fft wN W00➢LqWN : flQ ~ C~ ev ,~0 _ ~ T g SL• ' 'i , M APpw fYl ~jRp ~ YOARqe g YOPAOp ~ OMrzJ uana Ni LD ~ R ]AD ~ - m9N►Ldl C INT ~ CLIaSOn i I~ ie P ~ p~ Ov - f `3r~ G 1~ ~ ~ ~ m x~F p RFlle ".L{~ OF y s~ f~ YcCA6E M~eCA'9E o ~ ~a ~ a~ m ~ a~ Re a , wC Cx6 = m ~ m m 4' 0°1~ ~ B m ~ GKENBRp ; BEANE Ft0 ~ En m~`n BWRE Q..._ ' y ~ A,VA40H 8LiKE p~--~' rdik' ' m LE~-l-i^H~AaEr~~ A ATX !N 4 u6YqF • ~ A 136 Na z y~ p ~ m ua~[Po.. ~ MAMER FD IARM1fEA Ap 1_ ~ lMx~wEaF NA eA 77 h1ARiEft~ 9UA0 6A IS qp Q~ri ° noAVfS R g a , ~ oayig Y EVEI GREENa Rd EVERGFCEEN RDAp 1 Afi 5' f~ `~i= 9 ~M ` 3l =6syf ~~q N L~ q,/ 14~Q ~`t:~'r~+"`' .y ~ ~ Lful ~ ~ soelue ~ia~`eo~~ t~y 9+~b u m a,a eatnsa ~ ~ eOLIVaR ixx~Q0 EF NlAf Ci ~ ffAkHEAI 8AM F~f R ~ LN S~~ E~rsir oavn 6GL1 a0. MIH SU !ROOK Ra EiRIY GAW31 ~ c x el1iNE BkNHEN ~ 90UVAA K 6RNt3EN E s y"' ~+fV aa1 kNNlk a SBMNT99 1 R_ O t t ~&RHHSN ~ 9F yy~ 3uNN R 0.q BEST t~ 6i57 ~ BE9T BES' T [~(S ~ p lAIlNEH 6r BUSi R9 R ~T ~ * {R~r fi = ~~REES ~ e REES BESi 3- ~ eee ~ neee ~FS ~ ~ fp r~I Y~ W CALVIH c) ~rLviM ' N C Lvlp c K .4 r z O CALY" CAylN CALYiN SN m -10 A7~* CALVIN WARREH 1 0 4Y RAIME~N ,5 N 'KA 9EN ~4RREN ~ ~PhSRORD ~ I$ R4AM:~ ROAD , ' qancu ~ n q~ ~ rua a+ae !0 kMARA~IV 148 s a ;y h 9llRN9 RN 'm~ wC~I PRO6RE99 ROAB ~ Auari ~j 1~L1S 1 ~ T~NA t£5 S~"'y~ a~ Fdd'~ P a 9tl 1 ' SOk~11EA Sfl~ FduRR CE4 m ~Ew[R [s R qE%U • w P ME EP ~ ~EWlR ~ m 4Cq ~ a hY ^ ~ Y r L EWF~ ~ aLEpTUAt CT z exi - :Ep7u[~r T H~ ~ LI R ~ SIlLL9YANI R0 ermua ~ crrnu v- cE ZUav 5ULl.fVAN I fiOA[7 ~ CHEFYL °QIONH$kLN ~i ~ IOH 6 CT r~ N 156 Nr y~ x Ci ~e n ~ i a , ~~~,a~° ~z ,,yy1~~ =aVSd3BYtl ~ ~9fiRlANE ^-~y ~ a~KGR `'a ~ A~j' ' 'ISmm '47 ~ ~ - xAM6~n fd h ~Y ~ ~ i9 rY 'Py H ~ FST q 160 ' ~ ~7 ~ y ga0$~y a FQR 9 py C4NF7EAY A~ ~ ta a~ ei reLw ~ C6UKLIN Afl CONNIIN pa CARmIM! L~kIY HULLY'NGC1Q LN 1VY s r~ Ci N s P " 7 5XAIdAO R&7 ' L~4RNIN 58AtlA0CR a ~ ..4 N1aMNUan~ ~ Hf~~ l'•,Sw c a TPq ~ ~ s~ OxP 0 ~ y $ ~ p p ` A'I 4~~ AfGOiYpNilR I ~r~,, ~ ~ . y ~ ,•g' • 1~ dYhl rP xr` m 168 ~ a~ SrCEn Ro ~ sTeer~ ~n ~ z el zee + e 4 1[res3~~ N ~ x~~t [Fav~n N~,~ ~G-AP,kFF[~HC# ~ - - ..r ~ x~lira. ~4 S'~~ GxCC~ ~ ~~~c..w-~ ~ q . ~ c• _ _ _ ~ 172 £ 13 45 E C a . " aELL 99- ~ ~ AR 4 g ~ L eEtl B I7L08R LX roc~ .ALav p PCLT C ~ 511 R L S HIR EY Rn lT C7 ft] O7 .A Q C77 f17 L54 A Cl7 N E75 SOILS MAP Sheet 76 OF S+GS SUIL SLIRVEY OF SPOKANE CQJLJN7Y BOWSTRING CALCULATIONS. PEAK FLC7W CALCLILFITICJN pRqJEC°r. Prairie archard BpW5TRING METHDI] PRC].1ECT' Prairie Orchartt 10•Year Design Starm DE3ENTIQN BRSiN DESIGN BA51N' 1 ~ DESIGRIER 5KM _ BASIN. 1 DATE 27-Sep-02 Tat. Area 53,814 SF 3 24 AcreS Imp Area 16,950 5F Time Incrernent (min) 5 C= 0.39 Lawns 0.35 . Tims af Cone. (mirs) 5.39 tmp. 0.90 Ouiflaw (cfs) 9 Design Year Flow 10 CASE 1 Area {acres} 1 24 Impervious Area [sq fit) 16950 60 ft Overiand Flow 'C' Factos 039 Araa ' G 0 477 Ct = 095 "208" Imp Area 12,000 L = 64 ft. n= 0.40 Tirne Time Inc Intens 4 Devel Val In Vol Dut 5torage S= 0.0220 (mEn} (sec) {inlhr) Ws) [r.u ft] (cu ft) (cu ft) 539 324 3 08 1.47 637 324 313 Tc = 317 arain , Gy Equation 3-2 Qf GuidEhnes 5 300 3.18 1 52 6i43 300 310 200 ft Qiteh flQw 10 600 2 24 107 759 600 159 15 900 1.77 084 853 900 -47 Z1 = SO Q Far Z2 20 1200 1 45 0.69 906 1200 -294 72 = 50.a Type B= 1.17 25 1500 1.21 [}.58 930 15[]4 -570 n= 00116 Rolled ~ 3 5 30 1800 1 04 O.50 548 1800 -852 5- 0.0090 35 2100 0.91 043 950 2100 -1140 . . 40 2400 082 0.39 982 24{]0 -1418 d= 0:1400 ft Flvw INidth 7.0 ft. 45 2100 034 4 35 982 2700 -1708 50 3000 068 32 1 009 300(} -1991 55 3300 0.64 031 1041 3300 °2259 A R 4 7c Tc total I Qc 60 3604 0.61 0.29 1080 3600 -2520 0 98 0.07 1*37 2 22 5 39 3 08 1.47 65 3800 060 0 29 1148 3900 -2752 70 4200 058 0 28 1193 4200 •3007 Qpeak far Case 1= 1.47 cFs 75 4500 055 0 27 1232 4500 -3268 80 4800 0 53 025 1242 48(](] -3558 85 5100 052 0.25 1293 5100 -3807 90 5400 050 0 24 1315 5440 -4[}85 CASE 2 95 5700 0.48 0 23 1358 5700 -+1342 100 5000 [}.48 0.23 1399 5[]00 -4501 ' Gase 2 assumes a Time vf Concentrafion lass than 5 minutes sv that fhe peak flcsw =.90(3 1$)(Irnp. Araa) ~ 1 11 cfs "208" TREATMENT REQIJIREMEIVTS Minimum °208" Volume Required 500 cu #t Providsd Treatrnent Vvlume 5$3 cu ft 5a, the Peak flvw for the 8a5in is the greater af the two flows, 1.47 cfs DRYWELL REQUIREMENTS -1Cl YEAR DE51GN 570RM - Mirtimum 5torage Required by Bowsiting 313 Gu ft PmVided Sfvrage Valvme -934 cu ft Numberand Type of Drywells Specified 0 Single I oouble i ~ - - - , , - i - , ~ - i ~ ~ ~ - --_PEAK FLCIW CALCLILATlO'N PRpJECT"Prairie 6r,6hard.Bc3W5TRING METHf]D PRQJECT F'raine Drchard 10-Year Design Storm DETENTiON BASIN aEstGN sA5iN• 2 ❑E51GNER:SKM • 6A5 iN. dATE. 14-R~ug-02 1'Of AP@3 rz`~K `19,i498 S'~F 0.~15 RCreS •P.~, 3mp Area ;1,500 5F TEme Increment {min} 5 C= Q 4+l L.awns 0.15 Yime of Gonc. {min} 5 63 tmp. 6 90 Qutflow (efs) 0.3; Design Year Flow 10 CRSE 1 Area (acres) 0 45 ImpervIoLs Area (sq ft) 7500 ' • ~ , 184;ft. Overiand flow 'G' FactQr 044 ArQa ' C 0 198 Ct "208" lmp Area „ .3;208r L 180 ft n= Q,4Qq "Fime Time lnc. lntens QDewel Vvl In llvl Out 5tarage , S (mtn sec) 4anlhr •r.~, , ~ ,:_n_,~.x [ 1 (cfs] ~Gu ftJ fcu ftl (cu ft) 5 63 338 3.02 0.59 268 141 967 7c w 5.29 min , byEquafion 3-2 of Guidelines 5 300 318 0.62 251 90 161 ,`~:J'5D( ft Gutter f3vw 10 600 2.24 44 314 180 134 15 340 177 0.35 353 270 83 Z 1= For Z2 20 1200 145 0.28 374 360 14 ~2 = Q, a 7ype B= 1,0 25 1500 1 21 0 24 384 450 -fi6 n VC) C... 1~6 Ralied = 3.5 30 1800 1.04 020 391 54fY -149 5= 35 2100 0.91 018 396 630 -234 40 2400 0.82 0.46 405 720 -315 o-°~-~=- d= t.:~ nD.097,0j ft. Flaw Width 4.9 ft. 45 2700 074 015 409 $10 -401 50 3000 58 0.13 416 900 -484 55 3300 0 64 0.13 429 990 •561 R R ~ Tc TG tqtsl I ' Qc 50 3500 0.61 0.12 445 1080 -635 [].24 17.45 0.59 p 34 563 302 (].59 65 3900 060 012 473 1170 -697 70 4200 0.58 I} i1 491 1260 -769 Qpeak Far Case 1= 0.59 cfs 75 45[}0 056 ai1 547 7350 -843 80 4840 0 53 010 571 1440 -929 85 5100 0.52 0.10 532 1530 -998 90 5404 0.50 010 541 1620 -1479 GASE 2 95 5740 0.49 0.117 559 1710 -1151 100 5000 0.48 009 576 18[}0 -4224 Case Z assumes a Tirr►e of ConcentratEon Isss than 5 minutes so thaf the peak fiovv = 90(3.18)(lmp. Area) = 0.49 cfs "208" 7REATIVIEN7 REQIJIREMENTS Minimum "20$" Valume Required 134 cu ft Provided Teaatment Volume • a., eu ft So, the Peak flow for the 6asin is tha greatpr af the twv flows, 0.59 Cfs C7RYWELt REC]UIREMENTS - 10 YEAFZ aESIGN 5TC7RM Mirrirrtum Stflrage Rsquired by Bawstring 167 cu ft Prouided Storage Valume -,+cu ft Number and Type af Orywells 5pecified 1 Single 0 Qouhle ~ 1 ~ ~ - - - ~ - - - - I - PEAK FLOW CFILGl1LATIDN PRDJEGT:4PC;~irie,Orc~7ar,d BflWSTRING METNOQ PR4JECT Prairie Qrchard 10-Year Design Storrn ❑ETENTION 6A51N DE51C,N BA51N. 3 DESIGNER: S1CM . _ , BASIN: DATE: 14-Aug-02 ' Tot ArBa P y~31038 5F 0.71 Acres i , Imp Area It,'6,20{l SF Time inCrarrient (mirr) 5 C= 030 Lawns 0.15 Time of Conc. (mier} 5,95 Imp Q 90 Outflaw {cfs} •p,3~ DesignYear'Flow 10 CASE 1 Araa {acres} 0.71 Imperviflus Area (sq ft) 6200 .'2201 ft. Qverland Flpw 'C' Facfor 0.30 Area ' C 0.214 Ct "208" Imp Area L = 22{l fl. n= j;:'~ ]:4Q Time Time Inc. Intens ❑ Devei Vol In lAoi.Qut 54vrage 5 = Q:0684 (mEn) {sec] [inlhr] (cfs) [cu ft] (cu ft) [cu (t) 596 358 2 93 063 300 107 193 Tc = 4.93 min., by Equatian 3-2 vf Guidelines 5 304 318 0.88 273 90 183 ff Gutter flow 10 600 2.24 0.48 345 1$0 155 15 900 1,77 0.38 386 270 116 Z1 = ~'S[} Q~l Fvr Z2 20 1200 1 45 0 31 4[]9 360 49 Z2 = 1.0' Type B~ 10 25 1500 1 21 026 419 450 •31 n= .D 016i Ra91ed = 3.5 30 1800 1.04 022 427 540 -113 S= 35 2100 0.91 0.19 432 530 -198 40 2400 4.82 0.18 442 720 -278 d= 0,1380; fk Flow Width 59 ft. 45 2700 074 016 446 810 -354 50 3000 0.68 0.15 453 900 -447 55 3300 06.4 014 468 990 -522 A ~ Q TG Tc tvtaf I Qc 60 36(}0 061 013 485 1080 -595 0.38 4.06 6.63 1.03 5 96 2.93 0.53 65 3940 0.60 0.13 575 1170 -655 7{] 4200 058 012 535 1260 -725 Qpeak for Case 1= 0.63 cfs 75 4500 0 56 012 553 1350 -797 80 4800 053 0.11 557 1440 -883 85 5100 052 41l 580 1530 -950 90 5400 080 O11 590 1620 •1030 CAS E 2 95 5700 049 010 609 171(} -1 101 .,__a.._.. 100 6400 048 01(] 628 1800 -1172 Case 2 assumes a Time of Cancentcatian less than 5 minufes so that the peak flow c.90(3.1$)(Imp Area) = 0.41 cfs °208" TREATMENT REQUIREMENTS Minimurrc "208" Volume Required 70 cu ft Prmvided Treatrnent Vvfurne cu ft So, the Peak flow for the 6asin is the greater oi the two flows, 0.63 cfs ❑RYUVELL F;EQUIREMENTS - 10 YEAR 0.7E51G1V STORM Minir`cium Sfvrage Required hy Bowstring 193 cu ft Proaided 5torage VoPume cu ft Number and '1°ype of Qrywelis SpeciFed 1 Single 0 Qouble ' PEAK FLO1N CALCLJLATIC]N PROJECT:Prair_ie-[3rchard,t- . r_,. . _ - 1 a-Year Design Storm , SASIN.'4•PRE=i ' " ~ Tot. Area - 20,751' . SF 0.48 Acres Imp. Area - AM SF C = 0.32 rrieadow 0,30 1 mp. 0.90 CASE 1 220-ft. Overland Flvw Ct 0.15., ; i L = 220 ft. ' n - 0.40., S = 0_Q28D Tc = 6.44 min., by Equativn 3-2 Qf Guidelines ; - , .6, ft. Gut#er fiow Zi = 50.0 Fvr Z2 . Z2 _ 50.6; Type B = 1.0 } n- _ :A0i6; RoIIed = 3.5 5 = -A2OQO1 d= ft. F1vw Vlf idth 2.5 ft. , . . - A R Q 7c Tc fota! I Qc 0.12 002 0.43 0.00 6.44 2.81 0.43 ~ Qpeak fvr Case i = 0.43 cfs CASE 2 ~ Gase 2 assumes a Time of Concentrativn less than 5 minutes sa that the Reak flow -.90(3.18)(Imp• Area) 0.05 cfs ~ So, the Peak flvw for the Basin is fhe greater vf the twa flaws, - 0.43 cfs I' iI~ ' i I W~~ PE~4K FLa'' G~4LCULATIC)N PRO.lEGT: ` .Prairie~ grcha~d,;~~ti:~ . . . ,._.N: -4 1' %-.LL_ .).x 1 r! 10-1(ear Design 5tarm 6AS1N:'R4rP0 . Tot. Area 20,751; SF 0.48 Acres _ Imp. Area - , 20, SF C ~ 0.23 Lawns 0.15 - I m,p. fl.3{] CASE 1 . . - 220 ft. OvErland Flow +Ct L= 220 ft. ' n ' : Q:4(] S = ---~0,028{] Yc = 6.44 min., by Equation 3-2 vf Guidelines ' - 0 ft. +Gutter flow zi ~ 56.0 ForZ2 _ Z2 ~ ' - 50.0: Type B 1.0 n = .01-+5; Rofled = 3.5 - S - _fJ.2DD a', _ d= 43~: ft. '~low Width 2.2 f~. _A R Q Tc Tc total 1 Qc 0.09 0.02 0.31 0.00 6.44 2.81 0.33 ' Qpeak for Case 1 = 0.31 cfs i ~I - CAS E 2 ; iCase 2 a~sumes a Time of Concentration less than 5 minutes so that the peak flow =.90{3. 18}(imp. Area) ~ 0.14 cfs ~ So, the Feak flow for the Basin is the greater vf the trvv flows, 0.31 cfs , - - I - ~ ~ I ~ i - ~ - - - - PEAK FLDW CA,LCLJLATIC]N PRVJECT. P-_rairle Orchard,•, 80WSTRING METHDD PROJECT F'rairie 4rchard 10-Year Design Storm . . , . DE`fEdVTVON BA51N ❑ESIGN BASIN- 5 []ESlGhfER- 51tM . BASIN 5 ❑RTE, 14-Aug-02 TC]E APea 6,457,iSF O 15 AGFeS Imp Area y_46,4571 5F Time Inererrsent (min) 5 C = 090 Lawns a 15 - Time of Conc. (min) 5 00 . Imp 0.90 Qutf![aw (cfs) - 03 Design Year Flflw 10 CASE 1 Area {acres} 0,15 Impervivus Area (s4 ft) 6457 0'ft Glverland Flow 'C' Facfar fl gp - Area * C 0,133 Ct N~ ~ e•^. ,-,.~rt - "208" 1 mp Area 6,4571 L = 0 ft n` " Q 4Qa "fime Time lnc Intens C~ Devel Vvl.ln Val.Out Stvrage S _ .ea.~'~~D~ (mm) (sec) (iNhr) [cfs] (cu Ft) (eu ft) [cu ft] 5.00 300 3.18 4 42 171 90 81 Tc = 0.00 min , by Equafion 3-2 of Guidelines . 5 300 3.18 0 42 171 90 81 Y"•.~f#.Gutisrflr~w 10 60[} 2.24 030 210 18i] 30 15 904 1.77 0,24 237 270 -33 Z9 = Y50, p FDr Z2 20 1200 1.45 0 19 252 360 -108 Z2 = • 1.0 Type 6= 1.0 25 1500 1.21 016 259 450 -191 n= D D161 Ralled = 15 30 1800 104 0 14 2E4 540 -276 S 85 2100 0.91 012 267 530 -363 40 2400 0.82 011 274 720 -445 d w t] 0835+ft. Flow W€dth 4 2 ft 45 2700 0.74 010 277 $90 -533 rv' 50 3000 068 009 281 900 -619 SS 3300 064 0.09 290 990 -700 A R Cl Tc Tc tatal I QC 60 3600 0 51 008 349 1080 -779 0.18 0.04 042 2 26 5.00 3 18 0 42 65 3900 060 0.08 320 1170 -850 70 4200 058 008 333 1260 -927 Qpeak for Case 1= 0.42 cfs 75 4500 056 007 344 1350 -1 Q[1fi 80 4800 0 53 0,07 347 1440 -1093 65 5100 0.52 0 07 361 1530 •1 a 69 90 5400 fl 5f1 O.07 367 1620 -1253 CASE 2 95 5700 049 0.07 379 1714 -1331 100 6000 048 006 391 1800 -7409 Case 2 assumes a 7ime of Concentraticrn less khan 5 minutes sa that the peak t3ow =.90{3.18}(Imp. Area) = 0.42 cfs "208" TREATMENT REQUIREMENTS Minimum "208" V41ums Required 269 cu ft Prflvided Treatrnent V6lume ,:a,r ~ ~ ~u ft 50, the ReaK flow for the Basin i5 !he grea#er af the twp flpws, 0.42 Cts DRYWELL REQUIREhHEAfTS - 10 YEAR DE51Gh9 STC}RM Minimum Starage Requirsd by Bowstring 89 cu fi Pravided Storage Voiume . , , ~D-12r^ ~ cu ft . hlumber and Type of Gryweils Specifed I Smgfe 0 ooubie I ; ' I ! I , ~ , - - - - PERK FLaW GALCULAT6OIV PRO,fECT Prairie Orchard BQWSTRIAIG METFiQfl PRQJECT: Prairie Orchard 10-Year Design Storm OETENTIQN 6A51N aESIGN BASIN. 2 and 5(Pond C) DESIGNER 5KM BASIN. 2 snd 5(Pand C) QATE• 27-SeGr02 To#. Area 22.510, 5 F 0 52 Acres Imp. Area 10,592.5F Time IncremenY {min} 5 C= 0.50 'L.awns 4.15 • Time of Conc (min) 5£1 0 lmp. {}.90 Ouiflaw {cfs) Design Year FCQw 10 CA5 E 1 Area (acres ) 0.52 ImpEfVEd1]5 AfEa {Sq ft} 1(}512 180 ft aVeriand FIDw 'C' Factor 050 Area ` C 0.259 Ct = 0.15 "208" Imp. Area 6;220: L = 180 ft. rr = ' 0.4po- Time Time ine Intens Q [3e+rel, Vol ln Val.Out Storage 5 = 0.6360, (min) {sec) (inlhr) [cfs] [cu ft] (~u ft) (cu ft) , 5 61 336 3.02 078 352 0 352 TC = 5.2$ rrairr., by Equativn 3-2 df Guidehnes e== 5 300 3.18 0 82 33{] a 330 50.ft Gutterflow 10 640 2.24 058 414 0 414 15 900 1.77 046 454 4 464 Zi = 50A FQr Z2 20 1200 1.45 037 493 0 493 Z2 = 10 Typa B= 110 25 1500 1 21 0.31 505 0 505 n= '0.016 Rolled = 3.5 30 1804 104 O.27 515 fl 515 S= 00400 35 2100 091 0.24 521 0 521 40 2400 082 0.21 533 0 533 d= 0,1075 ft Flow Wadih 54 iL 45 2700 074 019 538 0 538 50 3000 068 018 547 o 547 55 3300 0 64 017 565 0 565 A R ❑ TC TG total I Qc 60 3600 061 0.15 5$6 0 586 029 0.05 0.78 0.32 5.61 3.02 0.78 65 3900 0.60 016 523 il 623 70 4200 058 0.15 6.47 0 647 ❑peak for Case 1= 0 78 cfs 75 4500 0,56 0 14 668 0 668 80 4800 0.53 0 14 573 4 673 " 85 5100 0.52 013 701 0 701 90 5400 050 013 713 0 713 CASE 2 95 5700 049 013 736 0 736 --T-==, 140 fiOQO 0.48 0 12 759 0 759 Case 2 assumes a Time of Corscentrativn less than 5 minutes sa that the peak flow =.90(3 18)(3mp Area) _ 0.69 cfs "2(}8" TREATMENT REQUIREMEIVTS Minirnum "24$" Volume Required 259 cu ft 'Arvvided 1`reatment VolumB 277 Cu ft 5rr, the Peak flow fvr the Basin is the great$r oF the twv flows, 0.78 cfs D RYWELL REQUIRE{NEIVTS - iQ YEAR D ESIGN STORN9 Minimum 5torage F7equired py Bowstring flcu ft PrDvided Storage Volume 451 cu ft Nurnber and Type o6 Drywells Specified 5ingle 0 Douhle i - - i - I - - I i , - , - - PEAK FLC]W CALCULA`fIC3N PFdC7JECT ~Pra9rie [Jrchard ~ ME~FfC3D PRC7JEC~. Praene Qrchard BvWSTRENG 10-Year []esign Storm ^ .N M. pETENTIOIW BASIiV DESIG1V BR59hl. 3 and 5{Pond R} ❑ESiGNER 51CM , BAS;N.;3,antl'5_[Pqnd A} DATE. 14-Aug t72 T~si F~rea ; . _39,4$3iSF 0.79 Acres Imp. Area 9,AFr4ji SF Time Increment {min} 5 C= 0 36 Lawns 4.15 Tirne of Conc (min) 5 89 lmp. 0.90 fJutflaw {Cfs} ❑esign Year Flow 10 ~ CASE 1 Area (acres) 079 Imperviaus Area {sq fk} 9545 .-r~ ~~'R~ w22~ it Overland Flow 'C' Factvr 0 36 Area ' C 0 285 Gt 1`5 "208" Imp Area 5;1fF9 L = 220 f#. n= '~1;4fl0! Time Time ~nc. Irstens Q Devel VoI fn Vol,Dui 5torage 5 = Q.06,80~ (min) (sec) {inlhr} (cfs) [cu ft) {cu Ft) {cu ft) 589 354 2.95 0 84 398 354 44 Tc = 4 93 min., by Equation 3-2 of Guidefines 5 300 118 091 354 344 64 114ft Gutter Flovd 10 600 2 24 4.64 459 600 -141 15 500 1.77 0.50 514 900 -388 Z1 = 50.0, ForZ2 20 1200 1.45 041 545 1200 -655 o Type B= 1.4 25 1500 1.21 Q 34 558 1500 -942 Z2 = 1= n= Rolled ~ 3 5 30 18[]0 1 04 0 30 559 9800 •1231 5= }O.Oi601 35 2100 0 91 0 26 575 2100 -1525 . . _ 40 2400 0.82 0.23 589 2440 -1 S11 d= 0.1315°ft. Fiow Width 6.6 ft 45 2700 0.74 0.29 594 2700 -2106 50 3(}00 0.68 O.19 604 3000 -2396 55 3340 064 Qi$ 623 3300 -2677 A R Q Tc Tc totaf I Qc 60 3504 0 51 017 646 3600 -2954 0.44 0.47 084 095 5 89 2 95 O.84 55 3900 060 017 667 3900 -3213 70 4200 4.58 0.17 714 4200 -3486 Opeak fvr Case 1= 0.84 cfs 75 4540 0.56 0.16 737 4500 -3763 80 4800 0.53 015 743 4800 -4057 85 5100 052 0.15 773 5900 -4327 90 5404 050 014 786 5404 -4614 CRSE 2 95 5700 0.49 Q 14 812 5700 -4888 100 60[]0 04$ 014 837 6000 -5163 Case 2 assurnes a Tirrie of Cvncenfration lass than 5 minutes so that the peak f1Qw =.90(3 18)(Imp. Area) = 0.63 cfs "208" TREATMENT REQiJIF2EMENTS Minimum "208" Vplume Requtred 213 cu ft Provided Treatm2rrt Vcrlume 284GCU ft Sp, the Peak fEoau for the Basin i5 the greater of the fwo filows, 0.84 cfs 0 R1`WELL REQUIREMEfVTS - 10 YEAR QESIGN 57DRM MinEmum 5tprage Re[{uired by Bowstnng 64 cu ft Provided 5torage Vralume ,4~6; cv ft Number and Type of Drywells Specified D 5mgla 1 Doub1s - i , - - , , , - - F~EAK FLOW CALCUL.RT6O€V PRr]JECT. Prairie Orchard BQWSTRIiVG METHQD PROJECT- Prairie flrchard 10-Year Qesign Storm [3ETENTIQN BASIN OESIGN BA511V. 2, 3, and S DES3GNER SI(NY 8A51N: 2, 3, and 5 DRTE: 27-Sep-02 Tot Area 56.953 SF 1.31 Acr$s Imp. Area 2G,757. 5F Time Increment (min) 5 C= 0 42 Lawns 0.15 . Time of Canc (min) 5.86 Imp. 0.90 Outflvw (efs) 1 Design Year F1ow 10 CASE 9 Area (acres) 1 31 ompervious Area (sq ft) 20157 180 ft. C}veriand Flow 'C' Faetor 042 Ar$a' C 0 543 Ct W [].15' "208° 1mp Area 11,340 L = 1 80 ft. . n _ 0.400 Time Time Inc Irrtsns 0 Devel, Vol.ln 11b1 Out 5tarage 5 = 0580 [mm] (sec) {iNhr) {cfs] (cu ft) [cu ft] [cu ft] 5.86 351 2.96 1 61 757 351 405 _ Tc = 4 37 mm , by Equakion 3-2 vf Gufdelines 5 300 3.18 1.73 895 300 395 200 ft. Gutter flow 10 600 2 24 1 22 876 600 276 15 900 1.77 0.96 980 9[]0 80 Z1 = 50,0 For Z2 20 1200 1 45 0 79 1039 1200 -161 Z2 = 1 0 Typa H =1 0 25 1500 1 21 066 1465 1500 -435 n= 0.03 fi RoIIsQ m 35 30 1s(?a 1 04 0 57 1085 1800 5315 5= 00160 35 2100 0.91 0.49 1097 2104 -1003 40 2400 0.82 045 1122 2400 -1278 d= 0.1680 ft. Flaw Width 8 4 ft 45 2700 6 74 0 40 9134 2700 -1566 50 3000 068 0.37 1152 3000 -1848 55 3300 0.E4 0.35 1189 3300 -2119 A R C1 Tc Tc total 1 Qc 60 3500 0 61 033 1233 3500 -2367 0.72 0A8 1 62 1 .48 5.86 296 1 61 55 3904 0 80 0.33 1310 39(]0 -2590 ' 70 4200 0 58 032 1361 4200 -2839 Qpe8k far Gase 1= 1.61 cfs 75 4500 056 030 1405 4500 -3095 80 4800 0 53 29 1497 4800 -3383 85 546[] 0.52 0.28 1475 5100 -3625 90 5400 0.50 0.27 1489 5400 -39€31 CASE 2 95 5700 0.49 0.27 1549 5700 -4151 9 00 6000 4.48 0.26 1596 6004 -44[)4 Case 2 assumes aTime of GonceMration less than 5 minutes sq 4hat fhe peak flow =•90(3.1 S)[Imp. Area) = 1 32 cfs "208" TREATfHENT REQUIREN1ENTi S Minirriurn °208" Volume Required 473 cu ft Providsd Treatment Voiume - Pond A 277 cu ft 50, 1he Pea1c flow for the BaSin is ihe greater vf the twa flvws. Prov3ded Treatmerrt Volurroe - Pond G 284 cu ft 1.81 cfs ❑RYWELL REQUIREMENTS - aa YEAR aE51GN 5TL1RM Minimum Sforage Required 4y Bowstring 405 cu ft Provided Sl,orage Volume - Porrd A 466 cu ft Prauided StQraga Walume - Pond C 459 cu ft Number and Typa of prywe915 Specified 0 5ingie 1 [3ouhle I- - - - , - i- - - ~ - - , i - - - - PEAK FLC)W CALCLJLATI[JN PROJECY: Prairie Clrchard ' BC3WSTRING iv1ETHc7D PROJECT, PrairEe C3rchard 50-Year Design Starm DETENTIQN BASIfV aESIGN BA51N: 1 DE51GNER.SFCNI BASIN- 1 DATE: 27-Ssp-02 Tot Area 53,814 5F 1.24 Acres Imp Area 16,950 SF Time Inerement (min) 5 Time of Canc. (min} 5 13 C= 4 39 Lawns 4 15 Dutfi1aw (cfs) 1 Imp 0.90 Llesign Year Flow 50 CRSE 1 Area (acres) 1.24 Imperrtiaus Rrea {sq ft} 15954 60 ff Overland Flow 'C' Factvr 0 39 Rrea ° C 0477 Ct = 015 "208" dmp. Area 12,004 . L = 60 ft n= 040 Time Time !nc lntens. Q DeVe1 Vol !n VoI.Qut Storage S _ 0,0220 (min) (sec) [inlhr) [cfs] (cu ft) [cu ft) [cu it] - 519 311 453 2.16 901 311 590 Tc = 3 17 min, by Equation 3-2 of Guidelinss 5 3(]0 318 1.52 610 300 310 200 ft ❑itch flaw 10 560 2.24 107 754 600 154 15 500 177 4.84 849 900 •51 Z1 = 500 Fvr Z2 20 1200 145 0.69 903 1200 -297 Z2 = 50.{] Type B= 1.0 25 1500 1.21 058 927 9500 -573 n= 0016 RoIIBd =15 30 1$00 104 050 946 18flo -854 S= , 0,0090 35 2100 0.91 043 958 2100 •1142 443 2404 0 82 0 39 980 2400 •1420 d= 0.1620 ft. FI❑w Width 8 9 ft. 45 2700 0.74 0 35 991 2700 -1709 54 3000 0.68 0 32 1008 3000 -1992 55 3300 0 64 0 31 1040 3300 -2250 A R Q Tc Tc t[rtal I Qc 50 3600 0.61 029 1079 3600 -2521 1.31 0.08 2.17 2.02 5.19 4.53 2 16 65 3900 [7.6{1 4 29 9147 3800 -2753 70 4200 0.58 0 28 1192 4200 -3008 Qpeak fQr Case 1= 2.16 efs 75 4500 p 56 027 1231 4500 -3269 80 4800 0 53 0,25 1249 4800 -3559 85 5100 0.52 0.25 1292 5100 -3808 90 5440 0.50 024 1394 5400 -4[]86 CASE 2 95 5700 049 0.23 1357 5700 -4343 100 6040 0.48 0.23 1398 5000 -4602 Cass 2 assumes a Time ot CQncentration Iess than 5 minutes so that the peak fl4w = 90{4 58}(Im,p Rrea) = 1.60 cfs °208" TREATMENT REQUIREMENTS MERimum "208° VvlUme Required 500 cu ft Pravided Treatment Vofurne 583 cu ft Sv, tha Psak flow far the Basin is the greater of the twv flows, 2.1$ Cfs OR'CWELL FtEQL@IREN1ENTS - 50 YEAR DE51GN 5TOF:M Minimum 5torage Requ€red by Bowstring 590 cu ft Pravided Storage Volucn9 930 Cu ft Number and Type of Drywells Specified 0 5ingle , I f3ouble - i - - - - - - I - - - - - - - -I , - i - i i - - ~ ' i i ' PEF1K FLnW CA'LGt1LATfON PRa,9ECT' ~r,alrie~ii~C7rCh~ar[i~,MBOWSTRING METHC]D PR{3JECT Prairie Qrehard 50-Year pe5lgn StDrm ~ DETENTIaN BASIN i7E51GN BASIN• 2 DE51GiWER"SECM -Lj: , BASIN°'._``:. _ 21 DATE. 14-Aug-02 ' Tot. Area .1 9;'4961 SF 0,45 Acres ' Imp, Area 7,5001 SF Time Increrrient (min) 5 - Time of Conc {min} 560 C= 044 Lawns 0.15 Uutflow (cfs) ' 03t Imp, 0.9CY De&ign Year Flaw 50 CASE 4 Area (acres) 0.45 ImperVious Area (sq ft) 7500 y#801ft. DaeMand Flow 'C' FaCtor p 44 Area ' C 0196 Ck= ::;~~2L18" Imq Area : : L = 180 F#. n° 0:-4 0) Time Time Inc. Intens. Q aewel VoE In Vral {]ut Sforage S = (m») (sec) (mFhr) (cis) 4cu ft] (cu ft) {cu Ft) 5.60 336 4.41 0.87 390 301 7c = 5 29 min , by Equation 3-2 of Guidelines 5 300 3.18 0.62 251 90 161 C]~ft ~utter ilow 10 600 2 24 044 314 180 134 Z1 = ~~e°rt 50°.0 15 900 1 77 4.35 352 270 82 For22 2C1 1200 1 45 028 374 380 14 ~'Z - r2~~'~`f 1.Q~ TYPe B=]A 25 1500 1.21 0.24 383 450 -67 ~ n= 'J:E F!olled = 3 5 30 1800 1.04 0.20 391 540 -149 5.= 00400 35 2100 091 0.18 395 630 -235 44 2400 0.82 016 405 720 -315 d= ft. Flow Wtdth 5 6ft, 45 2700 074 a.15 409 810 -401 50 3000 0.E8 0.13 416 900 -484 55 3300 064 0.13 429 990 -561 A Ft a Tc Tc t6tat I Qc 50 3604 0.61 12 445 9480 -635 032 0.06 6.87 31 5.60 4 41 0.87 65 3900 0.6(] 0.12 473 1170 -697 74 4200 058 0.11 481 1260 -769 Qpeak for Case 1= 0 $7 cfs 75 450[} 056 0.11 507 1350 -843 80 4840 0.53 010 511 1440 a929 85 5100 0.52 010 532 1530 -998 90 5400 fl 5f3 010 541 1620 -1079 CASE 2 95 5700 0.49 iq 559 1710 -1 i51 100 5000 0.48 009 576 1800 -1224 Case 2 assumes a Time af ConcentratiQn 1e55 than 5 minufes so that the peak flaw = 90[4 58](lmp Area) _ 0.71 cfs "208" TREATMENT REQUIREMEEVTS Min3mum "20$" Volurne Required 134 cu t# Rrpvided Treatmsnt Volume cu ft 50, the Peak flaw for the Basin is the greater of the two flows, 0.87 Cfs DRYUVELL REQL1IREMENTS - 50 YEAR DE51,r,EV STORM Minimum 5torage Required by 8qwstring 2$9 cu h Provided Skorage Volume . cW fi{ Number and Type of Drywells 5peciFiec! 1 single 0 C]auble i I ~ ~ - , - - - - - I - ~ - - i PE/aK FLQW ~GALCLJLRTIC3N PRDJECT. ~Psr,airie~QrClia~rd, BC7W5TRING METHOD PRQJECT- PraErie Orehard 50-YBar Design atorm DETEiWTION SASIN DE51GN BASIiV, 3 4ESIGNEF2`5!SM` 8A5EN aATE. 14-Aug-02 Tot Arsa °z."'.:~'31;q38 5F 0 71 Acres Imp, Anea 1F;20Q~SF Time 9ncrerrsent (mm) 5 • Time of Ganc (mEn) 5 87 C= 0.30 Lawns Q 15 Outflaw (cfs) - ; a,3; Imp, t] 90 CJesign Year Flow 50 CASE 1 Area (acres) 071 1'mpervious Area (sq ft) 6200 3=~" 20~(t. Overland Flow `C' Factor 0.30 Area ' C 0 214 Ct = z;rF s``~[]„15y "208" !mp Rrea . 1',675- L = 220 fl. n= ~Q".44 Time Time Inc. 1Mens. Q Qevel. VoV.ln Vt~l Out 5ivrage S = 580 (min) [sec] {iNhr} {cFs) [cu ft] (cu i#) (cu ft) 5 87 352 4 34 093 438 10E 332 Tc = 4 93 min, hy Equation 3-2 ofi Guidelines 5 300 3.18 0.68 273 90 183 ` 11 Q; ff Lautter flvw 10 660 2.24 0.48 344 180 164 15 900 1 77 038 386 270 116 Z1 = 'kbj Far Z2 20 1200 1.45 0.31 409 360 49 Z2 = : .1.0? Type B = 1 0 25 1500 1 21 026 419 456 -31 n= -C1.0161, Rnlled = 3 5 • 30 1800 104 022 427 540 -19 3 5= 6.(}160~ 35 2100 091 019 432 630 -198 40 2400 D 82 018 441 720 -279 d= r._ o 1365jft Flow Widih 6.8 ft. 45 2700 074 016 446 $14 -364 50 3(30[7 0.68 0.15 453 900 -447 55 3300 0 64 6 14 468 990 -522 A R Q Tc Tc total d cc Sa 3600 0.61 0.13 485 1080 -595 0.48 007 0.93 0.94 5.87 4 34 093 65 3900 0.60 0 13 515 1170 -655 70 42(]0 0.58 012 535 1260 -725 Qpeak for Case 1 ~ 0,93 cfs 75 4500 0 56 0 12 553 1350 -797 80 4800 0.53 011 557 1440 -883 85 5100 0.52 0.11 580 1530 -554 9(1 5400 0 50 Q 11 580 1620 -1030 CASE 2 95 5700 049 10 649 9710 -1 1Q1 100 6000 048 010 628 1800 -1172 Gass 2 assumes a7irna of Cnncentratign less #har) 5 minutes so that the peak f[ow = 90(4.58){Imp. Area} = 0.59 cfs "208" TREATMENT REQlJIf,EH1ENT5 Mirnmum "208" 1lolume Required 70 cu ft Provided Treatment Valume `cu ft Sa, the Peak flow for the Basin is the greater vf the two flflws, 0.93 Cfs DRYWELL REQUiREMEiVTS - 50 YEAR QESIGN STZ]RM Mmimum 5toraga Requireti hy Bnwstring 332 cu ft Prov3ded 5tarage Vnlume cu ft IVumber and Type of Drywells Specified 1 Single 0 Double - PEAK FLnW CALCULATIC)N PR9JECT: PraiCid,,C]fCh4,rd;-sj , 50-Year [3esign Storm BASIN:4;PREt Tat. Area 207751` SF 0.48 Acres lmp. Area 000 SF - C = 0.32 meadauv 0.30 Imp. [].90 CA5 E 1 - 220 ft. DVerland Flow Ct = '0.15 I L = 22[l ft. _ n = 44 5 = 0.0280 'Tc = 644 min., by Equativn 3-2 af Guidelines Q ft. Gufter flow Z1 = 50:0° Fvr Z2 _ Z2 = 50.0 Type g = 1.0 n = -6.016 Ro11ed = 3.5 5 ~ . Q.D200 d- ,D88Cl:ft, Flvw Width 4.4 ft. FI R Q Tc Tc total I Qc 0.39 0.04 0.64 0.00 6.44 4.18 0.64 ` Qpeak for Case 1 = 0.64 cfs CASE 2 ; Case 2 assumes a Time of Concentratian less than 5 minutes so fhat the - peak flaw =.30(4.58)(1mp. Area) = 0.08 cfs ; So, the Peak fRauv fvr the BasFn is the greater af the two flows, ' 0.64 cfs I ' PEAK FLOW GALCULATIDN PRQJECT:`Prai~~Warc~iar.d q , 50-Year oesign Stvrm ~ BA51N: ~;4 ~'~ST•;~- ~ ~Tot. Area 2~;75:1 SF 0.48 Acres J Imp. Area 2;Z(}0 5F ' ~ G = 0.23 Lawns 0.15 Imp, (}.9(} i CASE 1 . • 226 ft. Overland Flow ' Ct = - .0:1-5 L = 220 ft. n = 0.40 ~ - S = '0.0,2$~ : Tc = 6.44 min., by Equation 3-2 vf Guidelines ~ - '6 ft. (autter flow zi = . 50:6 For Z2 ~ Z2 = - 5(}:0 Type B=1.[l ~ n = _r 0:01-Rolled = 3.5 S = 0.0260i d= r~=6.0'760; ft. FIvw Wid#h 3.9 ft. R, R fl Tc Tc fvtal ! Qc 0.30 0.04 0.46 0.00 6.44 4.18 4_46 - Opeak for Case 1 _ 0.46 c#s - CAS E 2 Case 2 assumes a Time vf Cancentrativn Ress than 5 mfnu#es sv that the peak ffQUV =.90(4.58}(Imp. Area) = 0.21 cfs Sv, fhe Peak flvw for the Basin is the greater af #he twa flaws, ~ 0.46 cfs ~ ~ - - i- - - - - - ~ - - - PEAK FLQW GALCULATION PRC]JEGT: ~Pra9rie OrcYrard BOWSTRfNG METhIOD PRQJECT Pralrie Urchard 50-Yesr DeSlgfi StOrm DEi"ENTICJN BASIP1 pESPGN BASIN: 5 DE51GNER, 5KM BASIN: 5 QATE, 14-Aug-02 Tot llre2 ;~6;457r'ESF 4.15 Acres Imp Ares ' 4. 6,45T5F Time Increment {r`c'un) 5 . Time nf ConG (min) 500 C= 0.90 Lawns 0 15 C]utflow {Cfs} • •`0 3Imp 0 90 ❑esigrr Year Flaw 50 CASE 1 AreB (aCres) 015 w- Imperviosls Area (sq ft) 6457 a(f#. Querland Flow 'C' Factor 0.90 Area ' G 0.133 Ct= ~Y'•4,,(}'.~'S~ "208"Imp Area L Q ft. n~ -'f] 40t1 ~"ime Time Ine. Ir~tens. Qe+reL VoI.In Vo1 Q~at 5forage 5 0.0200S (min) (sec) {in,mr} (cfs] {cu ft} (cu Ft) (cu it) . 500 300 4 58 ' ❑.61 248 90 155 Te = 0,00 rnin., by Equatiorr 3-2 of Guidelines ~ s=- 5 300 318 0.42 171 90 81 ~-''32D'ft. Gutter ilow 90 600 224 030 210 180 30 15 904 177 0.24 237 274 -33 prrac : .,n Z9 For Z2 20 1200 1,45 0.19 252 360 -108 Z2= TypeB=l.a 25 1500 121 096 259 450 -191 n= Rolfed = 3 5 30 1800 1.04 0.14 264 540 -276 5= ~t'6:(}486~ 35 2100 0.31 012 287 630 -363 40 2400 082 Q 11 274 720 -446 d= 0.09601 ft. Flow Wsdth 4.8 ft. 45 2700 0 74 0.10 277 810 -533 50 3000 068 009 281 900 -619 55 3300 0.64 0.{}9 290 990 -700 A R Q TC TC totaf I QC 60 3600 061 00$ 341 1080 -779 0.24 0.05 0.81 2.06 5.00 4 58 061 65 3900 060 0.08 320 1170 -850 70 4240 0.58 0.08 333 9260 -927 ❑peak for Gase 1= 0.61 cfs 75 4544 0.56 007 344 1350 -1006 80 4800 0 53 0.07 347 1440 -1093 85 5100 O.52 3.07 361 1530 -7169 90 54[}0 050 007 367 1820 -1253 CASE 2 95 5700 0 49 0.07 379 1710 -1331 r- 100 6000 0 48 006 391 1800 -1409 Case 2 assumes a 7ima of Concentration less than 5 minutes so that the peak flow =.90(4.58)(lmp. Area) = 0 61 cfs "208° TREATNIEIVT RECtUIREMENTS Minimurn "208" Valume Reqwred 269 cu ft ProVided Treatment Vvlume - ' V• ;cu ff Sa, tha Peak flow for the Basin is 4he grester Qf t h e twa f~ows, . y~ J~, IY.61 G#5 ❑RY►NELL REQUIREMENTS - 50 YEAR DESIC,N STC7RA9 VV1inimum 5tqrage Required by Bowstring 156 cu ft Pravided 5tarage VoEume - cu ft Number and Type vf Drywells Specified 1 Single 0 Qouple - - - - - - - ~ PEAK FLOW CALCULATIDN PROJECT: Prairig Qrchard BCTWSTRING METHOD PROJECT, Prairde OrChard 50-Year Design Starm ❑E1'ENTItJM1t 6AS1N QE51GN 6A5fhl. 2 and 5A ❑ESIGNER SKM , BASIN; 2 and 5A DATE• 27-5ep-02 Tot. Rrea 22,510 5 F p 52 Acres Imp. ArBa '10,512 SF 3ime Increment {min} 5 • Time of Gonc. (min) 5.58 C= 050 [.awns 0 15 C]utflow {cfs} . 0' fmp. [1.90 Design Ye.ar Flow 50 CASE 1 Area {acres} 0.52 lmpervious Area (sq ft) 10512 180 ft. Gverland Flow 'C' Faetvr 0.50 Area ' C • O.259 Gt = 0.15 "208" Imp. Area 6,220 L = 18(7 ft, n= 0400 Time Time Inc, Intens. Q C]avei. Vol.ln VvLout 5tvrage 5 = 00360 [min] (sec) {inlhr) [cfs] [eu Fc] (cu it) (cu ft) 5.58 335 4 42 114 513 0 513 Tc = 5 29 min, by Equation 3-2 af Guadelines 5 300 3.18 0.82 330 0 330 50,ft. CutEer Nvw 10 600 214 058 413 0 413 15 900 1.77 0.46 464 0 464 Z 1= 50.0 For Z2 20 1200 1.45 0.37 492 0 492 Z2 = 1.0; Type B= 1.0 25 1500 1.21 0.31 505 4 505 n= 0016 RoIled - 3 5 30 1800 1 04 0 27 515 , 0 595 5 = , 0.0400 35 2100 10.91 0.24 521 0 521 40 2404 0 82 021 533 0 533 d= 0 9240 ft Flew Wtdth 6.2 ft. 45 2700 074 0.19 538 D 538 513 3000 0.68 0.18 547 0 547 55 3300 064 0.17 565 0 555 A R a Tc 7C total I Oc 50 3604 0 61 016 586 0 586 039 006 1.14 029 5.58 4 42 1 14 65 3940 064 016 523 a 623 70 4200 0.58 015 647 0 647 Qpeak for Gase 1= 1 14 cfs 75 4500 056 014 568 d 66$ 80 4800 053 014 673 0 673 85 5100 0.52 0.13 701 0 701 90 5400 0.50 013 713 0 713 CA5 E 2 95 5700 0 49 013 736 Q 736 100 6000 048 012 759 D 759 Gase 2 assumes a Time vf ConcentratiQn Iess than 5 mmvtes so that the peak flow =.90{4 58}(Imp Area) = 0.99 cfs "208" TREATMENT REQl11REMENTS Minimurn "208" Valume Required 259 cw Ft Provided `freatment Volume 277 cu ft So, the Peak flow far the Basin ss ihe greater of the two flows, 1.14 cfs ORYWELL REQLJIREMENTS - 50 YEAR DESIGN STORM Minimum 5tprage F$equired kay Bowstring a cu ft Provided Storage 1!oluma 451 cu ft Number and Type of Orywells 5pecifiied 0 Single 0 ❑oubfe ' - I- ~ i - i ~ -I - i I I i - --i -i . . 4, - . -r.. ._~..r _ PEAK FLOW GALCULATlflN PRnJECT',Pr .aiOrCh....Bftf° BOW57RlNG ME~'HQD PROJECT Praine ~3rchard Sfl-Year '~esign Starrt'i pE7'EN710N BASIN DE51GN 6A51Af. 3 and 5(Pond A) C7ESIGh1ER;5ECM 6ASifV; ~'S.and: 5'(03`hd R) DATE: 14-Aug-02 Tot. Area ' r. 34',483, 5 F 0.79 Acres Imp Area Tima Increment (min) 5 ^ Time of Conc {min} 580 C= 036 Lawns 0. 15 Outf€vw (c#s) ' i, Imp. 0.90 [7esign Year Flaw 54 CASE I Area ~acres} 079 Imperviaus Area (sq ft) 9845 Overiand FIow 'C' Factar 0,36 Area ' C 0285 Gt = ~~''a,,~' 0.151 "208" Imp Area L = 220 ff. n= Time T9me Inc, Iniens. 0 C3evel Vol,In VolAut 5torage 5 = ~''"Q~0680 (mm) [ssc) (inlhr) {cfs) (cu ft) (cu ft) {cv fR) 580 348 436 1 24 579 348 231 TG = 4.93 rnin , by Equatian 3-2 of Guidellnes ~w- 5 300 318 091 364 300 64 O,ft, Gutterflow 10 500 224 0 64 458 500 -142 15 900 177 0.50 513 900 -387 Z1 = J50 01 For Z2 20 1200 145 041 544 1200 -656 Z2 = 1~0. TypB 8= 9.0 25 1500 1 21 034 558 1500 -942 n= 'sf1.b161 RalIed = 3 5 30 1800 1,04 0 30 568 1800 -1232 S= _ 44~18{fj 35 21[30 091 0.25 575 2100 -1525 40 2400 0,82 023 588 2400 -1812 d= ' 52 qi ft, Flow Wadth 76 ft. 45 2700 0.74 021 594 2700 -2106 50 3[]04 0 68 a.19 604 3000 -2396 55 3300 0.64 4.18 623 3300 -2677 A R Q Tc Tc tatal I Qc 60 36(]0 f1.51 017 645 3600 -2954 0 59 0.08 124 0.87 5.80 4 36 1.24 55 3900 0.60 017 687 39[}[] -3213 70 4200 058 0.17 793 4200 -3487 • Qpeak for Case 1= 1.24 cfs 75 4500 0.55 0.16 737 4500 -3763 SQ 4840 053 015 742 4800 -4058 85 5100 0 52 O.1 S 773 5100 -4327 90 5400 O.5fl 014 786 5400 -4614 CASE2 95 5740 049 014 812 5700 -4888 100 60[}0 048 014 836 6000 -5164 Case 2 assumes a Time of Cvncentrafian less than 5 rrdinutes sa that the peak flow =.90(4,58){Imp Area} = 0 91 cfs "248" TREATMEIVT REQUIREMENTS Minimum "208" Volume ReGwred 213 cu ft Provicfed Treatment Vv9urrie ` 29cu ff So, the Peak flpw for the Basin is the greater of the two flows, 7.24 cfs ❑RYWELL REQUIREMENTS • 50 YEAE2DESIGN 57OF2M Minimum 5torage Required by Bowsfring 231 cu ft Provtded 5torage Volume 46Bs cu fit Numher and Type of Drywells apeCified 0 5ingl$ 1 Double - , - - , - , , i - - ~ PEAK FLC}W CALCULATIQN PROJECT• Prairie vrchard BC3WSTRING 1VtETHC1D PFtC1JEC7 PrauEe Orehard 50-Year Design Storm ❑ETENTIQN BASIN DE51Gh1 BA51N 2. 3, and 5 DE5IGNER Sf{M BASlN' 2, 3, and 5 QATE. 27-Sep-02 Tot Area 56,993 SF 1 31 Acrss Imp Area 20,957 5F 1'ime Increment {min} 5 . Time of Ganc {min} 5.72 C= 0.42 Lawns fl 15 C7utflaw (cfs) 1 Imp. 0.90 Design Year Flow 50 CASE 1 Area {acres} 1 31 ImperNious Area (sq ft) 20157 180 ft, Overland Flaw °G' Factor 0 42 ' Area ` C O.543 Ct = 095 "208" Imp Area 11,340 L = 180 ft. n= 0 400 T[me Time fnc. lntens Q Devef Val ln Val,out StRrage S ~ 00680 (rrim) (sec) [iNhr) icfs1 (cu ft) (cu ft) {cu ft) 5.72 343 4 38 2 38 1495 343 752 Tc = 4 37 m{n., by Eqvafion 3-2 af Guidelmes 5 300 318 173 695 300 395 200 fit. Gutter flow 10 660 224 1 22 872 5170 272 15 900 1.77 095 978 900 78 Z1 = 500 For Z2 20 1200 1 45 079 1037 1200 -1 fi3 Z2 = 1(7 Type B= 1.0 25 1500 1 21 0 56 9063 1500 -437 n= 0.018 Rolied = 3 5 30 18QLY 1 04 0.57 1 083 9 SOQ -717 5= 00160 35 2100 091 0.49 1095 2100 -1004 40 2400 O.82 045 1121 2440 -1279 d= 01940 ft. Fiow Width 9 7 ft 45 2700 0.74 40 1132 2700 •1588 50 3000 C?M, 0.37 1151 3000 -1849 55 3300 0 64 035 1188 3300 •29 12 A R Q Tc Tc total I ae 50 350[] 0 61 0 33 1232 3600 -2368 096 CY 9i3 2.37 1.35 5.72 4 38 2.38 65 3900 060 033 13(}9 3904 •2581 70 4200 0 56 0.32 1360 4200 -284p Qpeak for Case 1= 2 38 cfs 75 4500 055 0.30 1405 4500 -3495 80 4800 4 53 0.29 1416 4800 -3384 85 5100 052 0.28 1474 5100 -3625 90 5400 050 0 27 1499 -540[} -3901 GASE 2 95 5700 049 027 1549 5300 -4151 104 6000 048 026 1595 600[} -4405 Gase 2 assumes a Tirria oi Concentratian less than 5 rninutes so that ths peak flow = 90(4.58)(Imp. Area) = t 91 cfs "208' 7REA7MENT REf1UIREMEIVTS AAinimum "208" Volume Reguired 473 cu ft Provided Treatmen# Volume - Pond A 277 ru ft Sa, the Peak flow for the 8asin is the greater of the two flows, Prcauided Treatrnent Volume - Pflnd C 284, cu ft 2.35 efs DRYWELL REQIJIREMENTS - 50 YEe4R r3E51CaAI STf}Fift14 tUtinimum Stvrage Reqwired 4y Bowstring 752 cu ft Prouided 5torage Valume - Pand A 466 c.u ft F'rovided 5torage Volume - Rnnd C 451 cu ft Numher and Type of Qrywrells Specified 0 S+ngle 1 Dvuble INLET CALCULATIONS, _ _ I _ _ _ _ _ i - 1 I 1 I I . _ i' • Pxaine Qrchard S0201 60 Spokane Cnunty, Washington 0$l14102 , 50-Year Design 5torsn Engineer: F?NR CCTTRB INLET CALCLFLATTONS an CQntinuous Grade Curb Inlet Basin Basm } Gutter Aauginess I3epih Uischarge iniet By-Pass Pond Street-and , Peak F1Qw By-Pass 54ope CrQSS slope Caeff. Z of Flow per Length Length Flflw . , ~ . „r`Station'.. a „ - . ; .(cfs), S - 112 n n d * QalLa*~ La Q - Qa 24TH AVE C Sta 17+98.11 1.14 1.14 0.0552 0.0260 00160 3125 0.11 0.076 fi 0.68 24TH AVE - - - c Sta 18+09.21 0.68 0.0552 0.0200 0.0160 3125 0.09 0.063 5 0.31 24TH AVE A Sta 19+50.56 1.24 1.55 0.0167 0.0200 0.0160 3125 0.15 0.106 12 0.27 - - 24TH AVE A Sta 19+77.80 0.27 0.0181 0.020€1 0.0160 3125 0.08 0.055 S -4.00 NOTE: TYPES 1 8c 2 C`CTRB 11VI,ETS Curb Inlet Depression = 2 in. * Calculated ger Figure 18 ❑f the Spokane County Guidelanes far Starmwater Management Calculated per Frgure If of the Spokane Cauncy Guidelines fvr Stormwatcr Management CurbDropC i - , - ; - - ; i i , - - - - - - Prairie C7rchard S0201 34 Spokane County, Washington 09127102 , 50-Year Starm Event Engineer: DNR CURB DR[]P FLOW CAPACITTES sn 5ump Cvnditians Curb Tnlet Basin Basin + [erlei Maximum Maximum Hy-Pass Basin Street and Inlet Type Peak F14w By-Pass* Length Fi'ow Depth** I7ischarge*** Flow Station (cfs) Q (ft) H pa C? - C?a ' 8ums cul-de-sac TYPE a ~ Sta 1+$1 82 CURB 2.16 2 lf 400 0.50 4 37 -2.29 iNQTE• TYPE 1 CURB 1NLET TYPE 2 CURB 1NLE7' C7a = 3[l87 * L"H^ 1+15 Curb Iniet pepressivn =2 in. Curb [nlet Depressivn =2 in. Where L= Length vf CurTo Drop, H~ F1Qw I]epth Maxamum Inlet Height = 8in. Gurb IInlei Length =4 ft. Maximum Inlet Heigh[ = f in. * Fiy-Pass flows frorn upscream inlets on continuaus grades Maximum Flaw Depth ss based on Inlet herght Calculated per 5ectian 4-1 of the Spokane Caunty GurdeZines for Storrai►t ater Management Curb[JrvpS I FLOODED WIDTH CALCULATION. ~ ; 1 s' 7.6' FL4W WI61N " TYPICAL ROAD CR055-SECTION COLLEGTOR ARTER[AL, 2 LANE NC3N FL(3OI7Ed 2dNE WID`fH (FT) 1fi.❑ - ~ . i _