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27628 PE-1705B ' ' ' . ' ' , DRAINAGE REPORT for ~ Shelley Lake - 2" Addition Spokane County, Washington ' March,1999 IPE JOB #99029 1 ' Prepared by: Inland Pacifrc Engineering Comparry ' 707 W 7th Averrue, Szcite 200 Spokane, WA 99204 (509) 458-6840 ' . This report has been prepared by John McKervey, E.I.T. and the staff of Inland Pacific Engineenng Company under the direction of the undersigned professional engineer whose seal and signature ' aPPear hereon. ' t ti~ ~°x , 1 ~25462~ . EXPIRE _912~ „ Todd R. Whipple, P.E. ' f ' ' , DRA7NAGE REPORT FOR SHELLEY LAKE - 2"d ADDITION INTRODUCTION Shelley Lake 2°d Addition is part of the Shefley Lake PUD Plat and is adjacent to that portion of the Shefley Lake PUD which was included in the original Shefley Lake PUD Plat Drainage Report which , was completed in June, 1996 and approved. Basin P and Basin A-Temp which were part of the original Shelley Lake FUD drainage report have been incorporated into this report as portions of Basin A and Basin B. Shelley Lake 2' Addition includes 20 lots and adjoins the first phase of Shefley Lake at the southwest corner of the first phase. PURPOSE The purpose of this report is to detemvne the extent of storm drainage facilities -which will be re~quired to dispose ofthe increase in stormwater runoff createci by the development of Shefley Lake , 2 Addition. The storm dr ainage facilities for tlus project vvill be designed to dispose of runofffrom ten and fifty year design storms. This development is within the Aquifer Sensitive Area of Spokane ' County and is subject to `208' requirements. For this project the 10 and 50 year curves from the Spokane, Medical Lake, Reardon, Cheney and Rockford intensrty curves were used, as well as the SCS iso-pluvial rainfall curves. Per direcrion from Spokane County, the SCS curves have been further refined with the NOA►A► iso-pluvial curves. ANALYSIS METHODOL4GY ' . The Rational Method, which is recommended for basms less than ten acres in size, will be used to determine the peak discha.rges and runoffvolumes for a11 basins included in this report. ' PROJECT DESCRIPTION ' Shelley Lake 2°d Addition includes 201ots of the approved 2621ots and 459 units in the apProved preliminary plat and FEIS documents. The Shefley Lake subdivision is located in the North'/z ofthe SE 1/4 of the NE 1/4 of Section 242 T. 25 N., R. 44 E., W.M. within Spokane County, Washington. ' TOPOGRAPHY ' The eneral slo es within this lat v frm fl g p p ary o nearly at wrtlun several natural saddles to short slopes of up to 20-percent. Generally, the area covered by this report would be characterized as rolling. For development purposes, the natural slopin$ was used for design and is maimained as possible thrvughout the project. Inlartd Pacific Engineering 1 Shelley Lake 2"aAddition ' ' SDII.S As can be seen from the accompanying soils map from the Spokane County Soils Survey as . ' erf rm p o ed by the SCS, the srte consists of two soil types, both vvithui the Class B type. These soils are GgB and GmB and are described as follows. GgB - Garrison gravelly foam, 5 to 29 percent slopes: Soils within this soil type are somewhat excessively drained soils formed in gravelly glacial outwash material from a variety of igneous rock. ' Surface runoff is slow and the hazard of erosion is slight. Spokane County Guidelines for Stormwater Management indicate this to be a Soil Group Type B and pre-approved for drywell installation. Hydrologic Soil Classificution - B ' GmB - Garrison very gravelly loam, 0 to 8 percent slopes: This soil is generally the same as the ' Garrison gravelly loam, with the only difference being that the surface laYer is much more stonY and contains very little loam if any. Spokane County Guidelines for Stormwater ManaQement indicate this to be a Soil Group Type B and per-approved for drywell installation. ' Hydrologzc Soil Classrfication - B DRAINAGE NARItATIVE The offsite drainage which flows into Shelley Lake 2"d Addition has been incorporated into the basins included in this drainage report. As Shelley Lake 2nd Addition is located within the Aquifer Sensitive Area of Spokane County, all onsite drainage will be collected and treated using the `208' runoff ' method as described in the Spokane County Guidelines for Stormwater Manauement. To facilitate this analysis Shelley Lake 2"d Addition was divide into 3 basins (A►, B and D). The following Table 1 lists the basin deta.ils. 1 Table 1- Pond and Basin Summary ' Pond and B . asin Summary . • ~i Pond Basin Total Area *Total Impervious Weighted *1 , 208' Impervious ~ ' - ~ SF (AC) . Area SF (AC) `C' ` . Area'`SF A A 943,090 (2.16) 31,624 (0.73) 0.402 17,625 ~ B B 221,286 (5.08) 19,689 (0.45) 0.217 14,256 C C 62,726 (1.44) 62,726 (1.44) 0.900 62,726 D D 57,063 (1.31) 17,206 (0.40) 0.376 8,393 E E 972139 (2.23) 25,003 (0.57) 0.343 72385 * Total Impervious Area includes paved roadway area, 1600 st per roof and 600 s.f per driveway. `208' Impervious Area includes only the paved roadway area. Inland Pacific Errgineering 2 Shelley Lake 2"dAddition ' "208" Calculations ' Within each basin, the street areas from back of curb to back of curb were calculated to determine _ the required `208' storage. As shown on the `208' calculation worksheets inctuded, the `208' storage volumes provided are adequate to perform the ` 208' treatment for the fu-st half inch of rainfall. In ' addition to `208' treatment, the enclosed worksheets also show the calculations for the drywell requirements. The `208' storage and drywell requirements for each basin are summarized on the following Tabte 2. Table 2-`208' Treatment and Drywell Requirement Sununary `208' Treatment and Drywell Summary Pond Basin `208' Volume * `208' Area Required `208' Area , ~ . Drywells Required (CF) (SF) Provided Required A A 734 111096 1,120 1-Type B B B 594 887 2,192 1-Type B C C 2614 3,901 5,476 1-Type B D D 350 452 675 1-Type B E E 308 402 600 2-Type B * Based an a`208' starage depth of 8 inches. Side slope vofume is not included ?'otal Stormwater Storage Calculations In addition to the `208' storage requirements, the total stormwater storage for the 10-year design storm was also considered. Each of the ponds in Shelley Lake 2"d Addition will have the capacity to conta.in the required volume for the 10-year design storm. In addition, the 50-year design stomn was also exa.mined to determine the amount of overflow expected. This information is summarized in the ' following Table 3. ' ' Inland Pacific Engirreering 3 Shelley Lake 2"dAddition Table 3-1 U-year and 50~-year Stormwater Storage Volume Suntmary , - fi~- ~;-r,•::Y~ 0.,`. ~,i. = , ; ,L+i:l.:. t • . ;et;. ` . , Sl~, i , J' ~ i~ ' a Y 4-. f -0l ' ' t ~~`~+'~v.s : • r-,and 50-year Storage V_otame~-Sum~ma~/db~y ~~Bowstring ~ - . *~.:wt::-.c .'`a.=•~ . . . •~t~'y~r!~"~ J~.:~?s"`t%-e ~ • ~.'~'~i'~jp~`. ' .~rl-~~: k~(::~~,. • ~ . 1.-' '`'^"}!'4 M1.'- ~ ' ' ~ ` ci •^YNS '~~~~y~ ~ 1~.+~~ Y~ ~:v'.- . ;P ~Q ond 8asin ~ ~ 10-year ~year~~ '50:y,ear~ t4l s',sk; ' ' wi: , • i~~ 4;~ , %'~'.S :V.olume~ Volume_ -Volume l=j~ 1•. ` : i , ' ' • . • `~~~a~J} C" ~ ~ ~ Requlred Pr-ovide&7. rovided , ~ , ! °•w:~ ~ 'Y< f'~" ' ' , . • . • ~ (CF~~ L' A A 953 1)344 1,564 1,642 +78 B B 1,398 2,630 21208 . 2,954 +746 C C 3,461 6,571 5,496 7,323 +1,827 D D 339 810 607 1,056 +449 E E 369 720 841 958 +117 * SO-year Volume Provided 'mclucles side slapa volume As can be seen in Table 3 all of the ponds will contain the 10-year and 50-year design storms. Curb Drop/Inlet Analysis The inlet for Pond D is on grade and therefore a curb drop analysis was performed for this pond. The analysis shows that the pond requires 12.58 feet of curb drop opening, therefore 2- 4' inlets and 1- 5' inlet will be used to capture the stormwater for this pond. The inlets for the remaining ponds are in sump condition. ' ' Inland Pacific Engineering 4 Shelley Lake 2"dAddition i APpENWX ~ . ` ~`IG~os 1' ' / ~ . ~ SPOKANE COUNTY, WASHINGTON 1, R. 44 E. ~ R. 45 E. Y •ry' 7 J E. . ~ ~ ~ ~ ~~~1 . 'r ~ ~ IS./tr ~ , ~ . 1 . t ~ • . 9. r ~ " ~ . ' y :~~~~'G GgA~ j .,pA . "AUKEE ST PAUL . :t •h AND F'`. . . , ~ . ~ , s~ yWradalei , -t ~ ~ : • . Gm B ' ~ 'r ' ' • If " ~ " 3 ~Vr ~ e } '~r ' II ` . ;~~ff+y,}~', l~~ t ~ • .-~.ti . . 'i. . A I~ r 1►' r. G g , • / ~ ~Ir^ GmB 44 CkC C'ctt I V: c~ 24 PeA~ Sc•Itoo1 GmB PsA r ` ~'3r cf) G 13 ~ G A Jr i . ~•~~r . ~ PROJECT - ~ j LO CATIO N - - ~ ~ - H ` GmB HsB ~ BsB U h B " • - PsA - ' W. . . - - ~'Arri 1 PsA ~ - - N i~kQ~, _ . . L a(3 - ~ _ _ _ , ~ ~ m ~ l.►. C n U h B ' ~ - - BkC' CoB o. • . r •c :B f BB f B t ' ~ • B a B 6 ~J+ ~ rl l Q ~j } '..'^'9•. x •'~f1 l8 ' . ' • y - 's. -.t.. , ~~r~'~ •'~'r. By '^•'~,~"`~"a'x.` • ~ . ~w //H h7Q r ~ S L7 y~st~}~A<. v k .;~•r~ ~y~ ~jr~ I iw + . . ' ~~L"i'~..' ^a~~/~7~ ~ `~~ii , ~".~^-'t~.,~ p'y+h.. ~ . ~ NOT TO SCALE I NLAND PACiFic SHELLEY LAKE 2ND ADDITION ENCINEERING 707 wegc 7tn • suite 200 (sos) ass-ssao SOILS M AP DATE: 03/02/99 ~ Spokane, WA 99204 FAX: (509) 458-6844~ ~ 1 CVJ O ~ v ~ • • • ~ ~ ~r ' X~ ~TA.'• • _ ^ . ~ ^ ~ 4~ 1:~y~t:. ~ • • • • • ~ is~ ■ ~ . ~ ~ • a• • i w • ~ 2-~;~ty~-j!,~i.. ~ • O D O . . ~ Q • ~1 , O • ~ ~ ~ • O p rogress'.:.: ~ ~ ~ • ~ ~ ' ~ • • • • ~ • • • ~ r-h E ~ , ~ ~'ti., • • . . o ° •:~~~~~;:f, , o .0. . 't''4: . ~~.i ~ • • ~ ' U • ~ C~*f::;.~. ; . ' • • • ; , ° ~ : a aa"L:i~ • p ~ • • ~~-r:_~.'.:'.. O • I: , • • O' O ~1• ' . • ~ . O p ~lO ~ ~:s= :2029 ~ ' . • • • . • . . . : • : . : ~ • . . • . . . . • . • . . . - . ~ j4, . : . , WA Y EV. • Lc. . . o o a ; •~o I I . ~ • u ~ • . . o ~ o o ~ ; Jr fiiRti ~ . . ' . ~ • ~ ' ~ ~ °o SCR 'm ' i . ~ ~ • • ~ • ~ ~ , f ~1 • • • • 1 „ . • • • . I' • , . ` o • 11 Veradale z~:° . •!I: • 7e i1•. s.. . ~ = 4 tANE:.. ~ ~ : L ~ S~ • ' • ~W • ~ • • ~ 7 ~~A. ~f ~ • • . • • o. . ' . l . 1 . ~ ~ p os ~JO O a o . o a . +I • • . ~n f?ACIFIC S7 PAUL & ---t ~ -t ; ; : ~ y , ti ~ ~ • ~ ~ ( ~ Y \'~irO►• n ■ • if f:• ; Gravel Pitx - - - - • . . • o . ~ . . 4TH . • . . AYE oa ~ ~ . - ~e o Tra Ier_ ~ : 00 . . OFPark l . o • a - • ` lw , • ♦ . L~ ~ - ~ . SL~~,e ,~~rr•. ~ : : ~ , ~i: a )20 p ~ ~ ~ ) . ii.:_ ~ a 1 - • . ~ _1L ~ Cenlral 4 . ( • H ikh 5ch Sewa e Disp •1 ~ ,'f, ~ i- _ ds = . ' ' ii 1 ' .1 ` . i , X • ':~~t i I? . . 86 II . ••.t I . ° aYpit. .;t ~ . P ROJ LoC r - i, _ ~ / / I 'VE~_~~_~~--------jj` nk j ~i 04.1 Ji ~ ~ ~ • r ( ` ? ' j~ ~ ~ii . ~ ~ , '1.-•. J . ' NOT TO SCALE \ J INLAND SH ELLEY LAKE 2N D AD DI Tl ON PACIFIc ENGINEERING VI CI N I TY M AP 707 weet 7tn • suite 200 (sos) 458-6840 DATE: 03/02/99 ~ Spokane. WA 99204 FAX: (509) 458-6844~ ` , i . WEIGHTED `C' FACT4RS 1 ~ . ~ Weighted Runoff Coefficient Caiculation ~ Project: Shelley Lake 2nd Addition Basin: A IF'E Job 99029 Total Area (acres: 2.16 Designei J. McKervey ' Imp. Area (acres) 0.726 Date: 03/25/99 Grass Area (acre: 1.4340 Imp. Area "C": 0.9000 Grass Area "C": 0.15 (Imp. Area)(Imp. "C")= 0.6534 ' (Grass Area)(Grass "C")= 0.2151 2.1600 0.8685 Weighted "C"= 0.8685 0.4021 2.1600 ' 1 1 1 . ' ' Weighted Runoff Coefficient Calculafion , Project: Shelley Lake 2nd Addition Basin: B IPE Job 99029 Total Area (acres; 5.08 Designei J. McKervey ' I mp. Area (acres) 0.452 Date: 03/15/99 Grass Area (acre: 4.6280 Imp. Area "C": 0.9000 Grass Area "C": 0.15 . (Imp. Area)(Imp. "C")= 0.4068 (Grass Area)(Grass "C")= 0.6942 ' - 5.0800 1.1010 Weighted "C"= 1.1010 0.2167 5.0800 ' ' ' . ' ' Weighted Runoff Coefficient Calculation Project: Shelley Lake 2nd Addition Basin: C I PE Job 99029 Total Area (acres): 9.21 Designer: J. McKervey ' I mp. Area (acres): 1.44 Date: 03/25/99 Grass Area (acres): 7.7700 Imp. Area "C": 0.9000 Grass Area "C": 0.15 (Imp. Area)(Imp. "C")= 1.2960 , (Grass Area)(Grass "C")= 1_1655 9.2100 2.4615 Weighted "C"= 2.4615 0.267264 9.2100 ' t ~ IIVeighted Runoff CoefficEent Calculation ~ Project: Shelley Lake 2nd Additian Basin: D IPE Job 99029 Total Area (acres 1,31 aesignei J. McKervey Imp. Area (acres) 0.395 Daste: 03125/99 Gra~s Area (acre: 0.9150 Imp. Area nC'. 0.9000 Gl'asS Ar~~ ~~C"` 0.15 ; (Imp. Area)(Imp. "C"}= 0.3555 (Grass Area)(Grass 'TC")- 0.-1373 1.3100 0.4928 Weighted "C"- 0.492$ _ 0.3761 1.3100 ~ ~ ~ ~ Weighted Runoff Coefficient Calculation Project: Shelley Lake 2nd Addition Basin: E IPE Job 99029, Total Area (acres' 2.23 Designei J. McKervey r I mp. Area (acres) 0.574 Date: 03/25/99 Grass Area (acre: 1.6560 Imp. Area "C": 0.9000 Grass Area "C": 0.15 (Imp. Area)(Imp. "C")= 0.5166 (Grass Area)(Grass "C")= 0.2484 2.2300 0.7650 Weighted "C"= 0.7650 0.343 2.2300 ' ' . ~ ~~7 S~'~SG C""LC~ B ~ ~rj~J ~ r ~■r ~ r ~r ~ ~ ~ ~ i■r ~ ~ ~ ~ ~ ~ ~ ~ ~ BOWSTRING METHOD PROJECT Shelley Lake 2nd Addition PEAK FLOW CALCULATION PROJECT:Shelley Lake 2nd Addition DETENTION BASIN DESIGN BASIN: A 6ASIN: A 10-Year Design Storm DESICNEf J. McKervey Tot Area 2.16 Acres DATE: 04106199 Imp. Area 17625 SF C = 0.40 Time Increment (min) 5 CASE 1 Time of Conc. (min) 9.24 outflow (cfs) 1 76 ft. Overiand Flow Design Year Flow 10 Area (acres) 2.16 Ct = 0,15 Impervious Area (sq ft) 17625 L= 76 ft. 'C' Factor 0.402 n= 0.40 '208' Volume Provided 750 S= 0.030 Area " C 0.868 Tc = 3.33 min., by Equation 3-2 of Guidelines Time Time 1nc. tMens. Q Devel. Vol.ln Vot.Out Storage 700 h Gutter flow (min) (sec) (inlhr) (cfs) (cu ft) (cu ft) (cu ft) Z1= 50.0 For Z2 9,24 554 2,34 2.03 1507 554 ~ 953 Z2= 3.5 Type6=1.0 n= 0.016 Rolled = 3.5 5 300 3.18 2.76 1110 300 810 S= 0.010 10 600 2.24 1.95 1534 604 934 15 900 1.77 1.54 1673 900 773 d= 0.196 ft. 20 1200 1.45 1.26 1748 1200 548 25 1500 1.21 1.05 1774 1500 274 A R Q Tc Tc total I Qc 30 1800 1.04 0.90 1796 1800 -4 35 2100 0.91 0.79 1808 2100 -292 1.03 0.10 2.03 5.91 9.24 2.34 2.03 40 2400 0.82 0.71 1843 2400 -557 45 2700 0.74 0.64 1856 2700 -844 Qpeak for Case 1= 2.03 cfs 50 3000 0,68 0.59 1883 3000 -1117 55 3300 0.64 0.56 1939 3300 -1361 60 3600 0,61 0.53 , 2007 3600 -1593 CASE 2 65 3900 0.60 0.52 2130 3900 -1770 70 4200 0.58 0.50 2210 4200 -1990 Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.56 0.49 2280 4500 -2220 peak flow =,90(3.18)(Imp. Area) = 1.16 cfs 80 4800 0.53 0.46 .2296 4800 -2504 85 5100 0,52 0.45 {2388 5100 -2712 90 5400 0.50 0.43 2426 5400 -2974 So, the Peak flow for the Basin is the greater of the iwo flows, 95 5700 0.49 0,43 2505 5700 -3185 2.03 cfs 100 6000 0.48 0,42 2579 6000 -3421 208' DRAINAGE POND CALCULATIONS Required '208'Storage Volume Impervious Area x.5 in ! 12 infft 734 cu ft 208' Storage Volume Provided 750 cu ft DRYWELL REQUIREMENTS -10 YEAR DESIGN STO Maximum Storage Required by Bowstring 953 cu ft Total Storage Provided 1007 cu ft Number and Type of DryweUs Required 0 Single 1 Double ~ ~ ~ ~r ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ r ~ ~ BOWSTRING METHOD PROJECT: Shelley Lake 2nd Addition PEAK FLOW CALCULATION PROJECT Shelley Lake 2nd Addition DETENTION BASIN DESIGN BASIN: B BASIN: B 10-Year Design Storm DESIGNER: J. McKervey Tot. Area 5.08 Acres DATE: 03125199 Imp. Area 14256 SF C = 0,22 Time Increment (min) 5 CASE 1 Time of Conc, (min) 9.70 OuMow (cfs) , 1 680 ft. Overland Flow Design Year Flow 10 Area (acres) 5.06 Ct = 0.15 Impervious Area (sq ft) 14256 L= 680 ft. 'C' Factor 0.22 n= 0.40 '208' Volume Provided 1469 S= 0.100 Area " C 1.118 Tc = 8.65 min., by Equation 3-2 of Guidelines Time Time Inc. Intens. Q Devel. Vol.ln Vol.Out Storage 200 ft. Gutter flow (min) (sec) (iNhr) (cfs) (cu ft) (cu ft) (cu ft) Z1 = 50.0 For Z2 9.70 582 2.27 2.54 1980 582 1398 Z2 = 3.5 Type B =1.0 ' n= 0.016 Rolled = 3.5 5 300 3.18 3.55 1429 300 1129 S= 0.030 10 600 2.24 2.50 1998 600 ' 1398 15 900 1.77 1.98 2172 900 1272 d= 0.174 ft, 20 1200 1,45 1.62 2265 1200 1065 25 1500 1.21 1.35 2296 1500 796 A R Q Tc Tc total I Qc 30 1800 1,04 1.16 2322 1800 522 35 2100 0.91 1.02 2337 2100 237 0.81 0.09 2.54 1.06 9.70 2.27 2.54 40 2400 0,82 0.92 2381 2400 -19 45 2700 0.74 0.83 2397 2700 -303 Qpeak for Case 1= 2.54 cfs 50 3000 0.68 0.76 2430 3000 -570 55 3300 0,64 0.72 2502 3300 -798 60 3600 0.61 0.68 2589 3600 -1011 CASE 2 65 3900 0.60 0.67 2748 3900 -1152 70 4200 0.58 0.65 2851 4200 -1349 Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.56 0.63 2940 4500 -1560 ' peak flow =.90(3.18)(Imp. Area) = 0.94 cfs ; 80 4800 0.53 0.59 2960 4800 -1840 85 5100 0.52 0,58 3019 5100 -2021 90 5400 0.50 0.56 3128 5400 -2272 So, the Peak flow for the Basin is the greater of the two flows, 95 5700 0.49 0.55 3230 5700 -2470 2.54 cfs 100 6000 0.48 0.54 3325 6000 -2675 208' DRAINAGE POND CALCULATIONS Required'208' Storage Volume Imperoious Area x.5 in I 12 inlft 594 cu ft 208' Storage Volume Provided 1469 cu ft DRYWELL REQUIREMENTS -10 YEAR DESIGN STORI Maximum Storage Requiretl by Bowstring 1398 cu ft Total Storage Provided 1973 cu ft Number and Type of Drywells Required 0 Single 1 Double BOWSTRING METHOD PROJECT: Shelley Lake 2nd Addition PEAK FLOW CALCULATION PROJECT Shelley Lake 2nd Addition DETENTION BASIN DESIGN BASIN: C BASIN: C 10-Year Design Storm DESIGNER: J. McKervey Tot. Area 9.21 Acres DATE: 03125199 Imp. Area 62726 SF ~ C = 0.27 Time Increment (min) 5 CASE 1 Time of Conc. (min) 5.00 Outflow (cfs) 1 300 ft, Overland Flow Design Year Fiow 10 Area (acres) 9.21 Ct = 0.15 Impervious Area (sq ft) 62726 L= 300 ft. 'C' Factor 0.267 n= 0,02 '208' Volume Pravided 3669 S= 0.020 Area " C 2.459 Tc = 1.24 min., by Equation 3-2 of Guidelines Time Time Inc. Intens. Q Devel. Vol.ln Vol.Out Storage 1050 ft. Gutter flow (min) (sec) (iNhr) (cfs) (cu ft) (cu ft) (cu ft) Z1= 25.0 For Z2 5.00 300 3.18 7.82 3144 300 2844 Z2 = 1 Type B =1.0 - n= 0.016 Rolled = 3.5 5 300 3.18 7.82 3144 300 2844 S= 0.045 10 600 2.24 5.51 3867 600 3267 15 900 1.77 4.35 4361 900 3461 d= 0.322 ft. 20 1200 1,45 3.57 4642 1200 3442 25 1500 1.21 2,98 4767 1500 3267 A R Q Tc Tc total I Qc 30 1800 1,04 2,56 4864 1800 3064 35 2100 0.91 2.24 4928 2100 2828 1.35 0.16 7,82 3.02 5.00 3.18 7.82 40 2400 0.82 2.42 5045 2400 2645 , 45 2700 0.74 1.82 5099 2700 2399 Qpeak for Case 1= 7.82 cfs 50 3000 0.68 1.67 5187 3000 2187 55 3300 0.64 1.57 5354 3300 2054 60 3600 0.61 1.50 5553 3600 1953 CASE 2 65 3900 0.60 1.48 5905 3900 2005 70 4200 0.58 1.43 6136 4200 1936 Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.56 1.38 6337 4500 1837 peak flow =.90(3.18)(Imp. Area) = 4.12 cfs 80 4800 0.53 1.30 6389 4800 1589 85 5100 0.52 1.28 6652 5100 1552 90 5400 0.50 1.23 6765 5400 1365 So, the Peak flow for the Basin is the greater of the two flows, 95 5700 0,49 1,20 6991 5700 1291 7.82 cfs 100 6000 0.48 1.18 7203 6000 1203 208' DRAINAGE POND CALCULATIONS Required'208' Storage Volume , = Impervious Area x.5 in I 12 inlft 2614 cu ft 208' Storage Volume Provided 3669 cu ft DRYWELL REQUIREMENTS -10 YEAR DESIGN STORM Maximum Storage Required by Bowstring 3461 cu ft Total Storage Provided 4928 cu ft Number antl Type of Drywells Required 0 Single 1 Double BOWSTRING METHOD PROJECT: Shelley Lake 2nd Addition PEAK FLOW CALCULATION PROJECT Shelley Lake 2nd Addition DETENTION BASIN DESIGN BASIN: D BASIN: D 10-Year Design Storm DESIGNER: J. McKervey Tot. Area 1.31 Acres DATE: 03J25199 Imp. Area 8393 SF C = 0.38 Time Increment (min) 5 CASE 1 Time af Conc. (min) 5.17 Outflow (cfs) 1 23 ft. Overland Flow Design Year Flow 10 Area (acres) 1.31 Ct = 0.15 Impervious Area (sq ft) 8393 L= 23 ft. 'C' Factor 0.38 n= 0.40 '208' Volume Provided 452 S= 0.020 Area * C 0.498 Tc = 1.84 min., by Equation 3-2 of Guidelines Time Time Inc. Intens. Q Devel. Vol.ln Vol.Out Storage < 480 ft. Gutter flow (min) (sec) (inmr) (cfs) (cu ft) (cu ft) (cu ft) Z1= 50.0 For Z2 5.17 310 3.14 1.56 649 310 339 Z2= 3.5 TypeB=1.0 n= 0.016 Rolled = 3.5 5 300 3.18 1.58 636 300 336 S= 0.020 10 600 2.24 1.12 787 600 ' 187 15 900 1.77 0.88 886 900 -14 d= 0.156 ft. 20 1200 1.45 0.72 942 1200 -258 25 1500 1.21 0.60 967 1500 -533 A R Q Tc Tc total I Qc 30 1800 1.04 0.52 986 1800 -814 35 2100 0.91 0.45 999 2100 •1101 0,65 0.08 1,56 3.33 5.17 3.14 1.56 40 2400 0.82 0.41 1023 2400 -1377 45 2700 0.74 0.37 1033 2700 -1667 Qpeak for Case 1= 1,56 cfs , 50 3000 0,68 0.34 1051 3000 -1949 . 55 3300 0.64 0.32 1085 3300 -2215 60 3600 0.61 0.30 1125 3600 -2475 CASE 2 65 3900 0.60 0.30 1196 3900 -2704 70 4200 0.58 0.29 .1243 4200 -2957 Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.56 0.28 1284 4500 -3216 peak flow =.90(3.18)(Imp. Area) = 0.55 cfs 80 4800 0.53 0.26 1294 4800 -3506 ' 85 5100 0.52 0.26 1347 5100 -3753 90 5400 0.50 0.25 1370 5400 -4030 So, the Peak flow for the Basin is the greater of the two flows, 95 5700 ' 0.49 0.24 1416 5700 -4284 1.56 cfs 100 6000 0.48 0.24 1459 6000 -4541 208' DRAINAGE POND CALCULATIONS Required'208' Storage Volume , = Impervious Area x,5 in 112 iNft 350 cu ft 208' Storage Volume Provided 452 cu ft DRYWELL REQUIREMENTS -10 YEAR DESIGN STORI Maximum Storage Required by Bowstring 339 cu ft Total Storage Provided 452 cu ft Number and Type of Drywells Required 0 Single 1 Oouble r ~ ~ ~ r ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ r ~ ~ BOWSTRING METHOD PROJECT: Shelley Lake 2nd Addition PEAK FLOW CALCULATION PROJECT Shelley Lake 2nd Addition DETENTION BASIN DESIGN BASIN: E BASIN: E 10•Year Design Storm DESIGNER: J. McKervey Tot. Area 2.23 Acres DATE: 03125/99 Imp. Area 7385 SF C = 0.34 Time Increment (min) 5 CASE 1 Time of Conc. (min) 7.03 Outflow (cfs) 2 90 ft, Overland Flow Design Year Flow 10 Area (acres) 2.23 Ct = 0.15 Impervious Area (sq ft) 7385 L= 90 ft. 'C' Factor 0,34 n= 0.40 '208' Volume Provided 402 S= 0.020 Area " C 0.758 Tc = 4.16 min., by Equation 3-2 of Guidelines Time Time Inc. Intens. Q Devel. Vol.ln Vol.Out Storage 440 ft, Gutter flow (min) (sec) (inlhr) (cfs) (cu ft) (cu ft) (cu ft) Z1 = 50,0 Far Z2 7.03 422 2.68 2.03 1146 843 303 Z2 = 3.5 Type B =1.0 n= 0.016 Rolled = 3.5 '5 300 3.18 2.41 969 600 369 S= 0.020 10 600 2.24 1.70 1263 12001 63 15 900 1.77 1.34 1400 1800 -400 d= 0.172 ft. 20 1200 1.45 1.10 1477 2400 -923 25 1500 1.21 0.92 1508 3000 -1492 A R Q Tc Tc total I Qc 30 1800 1.04 0.79 1532 3600 -2068 35 2100 0.91 0.69 1548 4200 -2652 0.79 0.69 2.03 2.86 7.03 2.68 2.03 40 2400 0.82 0.62 1581 4800 -3219 45 2700 0.74 0.56 1595 5400 -3805 Qpeak for Case 1= 2.03 cfs 50 3000 0.68 0.52 1621 6000 -4379 55 3300 0.64 0.49 1671 6600 -4929 60 3600 0.61 0.46 1731 7200 -5469 CASE 2 65 3900 0.60 0.45 -1839 7800 -5961 70 4200 0.58 0.44 1910 8400 -6490 Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.56 0.42 1972 9000 -7028 peak flow =,90(3.18)(Imp. Area) = 0.49 cfs 80 4800 0.53 0.40 1986 9600 -7614 85 5100 0.52 0.39 2067 10200 -8133 90 5400 0.50 0.38 2101 10800 •8699 So, the Peak flow for the Basin is the greater of the two flows, 95 5700 0.49 0.37 2171 11400 -9229 2.03 cfs 100 6000 0.48 0.36 2236 12000 -9764 208' DRAINAGE POND CALCULATIONS Required'208' Storage Volume , = Imperoious Area x.5 in ! 12 inlft 308 cu ft 208' Storage Volume Provided 402 cu ft DRYWELL REQUIREMENTS -10 YEAR DESIGN STORI Maximum Storage Required by Bowstring 369 cu ft Total Storage Provided 540 cu ft Number antl Type of Drywells Required 0 Single 2 Double ~ 50-year STORM BOWSTRING METHOD PROJECT; Shelley Lake 2nd Addition PEAK FLOW CALCULATION PROJECT:Shelley Lake 2nd Addition DETENTION BASIN DESIGN BASIN: A BASIN A DESIGNEf JEM Tot Area 2.16 Acres DATE; 04106 Imp. Area 17625 SF C = 0.40 Time Incremert (min) 5 CASE 1 Time of Conc. (min) 8.76 Outflow (cfs) 1 76 ft, Overland Flow Design Year Flow 50 Area (acres) 2.16 Ct = 0.15 Imparvious Area (sq ft) 17625 L= 76 ft. 'C' Factor 0.402 n= 0.40 '208' Volume Provided 750 S= 0.030 Area ' C 0.668 Tc = 3.33 min., by Equation 3-2 of Guidelines z Time Ttme Inc. Intens. Q Qevel, -Vol.ln Vo1.0ut Storage 700 R Gutter flow (min) (sec) (inlhr) (cfis) (cu ft) (cu ft) (cu ft) Z1= 50.0 8,76 525 3.28 2,85 2008 525 1482 Z2 = 3.5 n= 0.016 5 3Q0 4.58 3,98 1599 300 1299 S= 0.010 10 600 3,20 2,78 2164 600 o 1564 15 90Q 2,45 2.13 2295 900 1395 d= 0.223 ft. 20 1200 1.95 1.69 ' 2334 1200 1134 25 1500 1,62 1.41 2361 1500 861 A R Q Tc Tc total I Qc 30 1800 1.56 1.35 2680 1800 880 35 2100 1.28 1.11 2533 2100 433 1.33 0.11 2.85 5.42 8.76 3.28 2.85 40 2400 1,19 1.03 2653 24Q0 253 45 2700 1.08 0.94 2704 2700 -0 Qpeak for Case 1= 2.85 cfs 50 3000 0,99 0.86 2732 3000 -268 55 3300 0.92 0.60 2779 3300 -521 fiU 3600 0.87 0.76 2855 3600 -745 CASE 2 65 3900 0.82 0,71 29Q4 3900 -995 70 4200 0.80 0,69 3042 4200 -1158 Case 2 assumes a Time of Concentration less than 5 minuties so that the 75 4504 0.77 0,67 3128 4500 -1372 peak flow =.90(4,58)(Imp. Area) = 1,67 cfs 80 4800 0.75 0.65 3242 4800 -1558 85 5100 0.72 0,63 3300 5100 -1800 90 5400 0.71 0.62 3439 5400 -1961 So, the Peak flow for the Basin is the greater of the two flows, 95 5700 0.69 0.60 3522 5700 -2178 2.85 cfs 100 6000 0.67 0,58 3595 6000 -2405 208' DRAINAGE POND CALCULATIONS Required'208' Storage Volume = Impervious Area x,5 in 112 inlft 734 cu ft ' '208' Volume Provided 750 cu ft DRYWELL REQUIREMENTS - 50 YEAR DESIGN STORM Maximum Storage Required by Bowstring 1564 cu ft Total Storage Provided 1007 cu ft Number and Type af Drywells Required 0 Single 1 Doubfe fNLAND PACIFIC EM(31NEERING ' m m r m m m m m m m m m m i m m m m m 50-year STORM BOWSTRING METHOD PROJECT Shelley Lake 2nd Addi6on PEAK FLOW CALCULATION PROJECT Shelley Lake 2nd AddiGon OETENTION BASIN DESIGN BASIN: B BASIN B DESIGNEIJEM Tot. Area 5,08 Acres DATE; 03125 Imp. Area 14256 SF C = 0,22 Time Increment (min) 5 . CASE 1 Time of Conc, (min) 9.61 ` Outflow (cfs) 1 680 ft. Overland Flow Design Year Flow 50 Area (acres) 5.08 Ct = 0.15 Impervious Area (sq ft) 14255.67 L= 680 ft. 'C' Factor 0.217 n= 0.40 '208' Volume Provided 1469 S= 0.100 Area * C 1.102 Tc = 8.65 min., by Equation 3-2 of Guidelines Time Time Inc. Intens. Q Devel. Vol.ln Vol.Out Storage 200 ft. Gutter flow (min) (sec) (iNhr) (cfs) (cu ft) (cu ft) (cu ft) Z1= 50.0 9.61 577 3.07 3.38 2613 577 2036 Z2 = 3.5 n= 0.016 5 300 4.58 5.05 2030 300 1730 S= 0.030 10 600 3.20 3,53 2808 600 2208 15 900 2.45 2.70 2960 900 2060 d= 0.198 ft, 20 1200' 1.95 2.15 3001 1200 1801 25 1500 1.62 1.79 3029 1500 1529 A R Q Tc Tctotal I Qc 30 1800 1.56 1,72 3433 1800 1633 35 2100 1.28 1.41 3240 2100 1140 1.05 0,10 3.62 0,97 9.61 3.07 3.38 40 2400 1.19 1.31 3391 2400 991 45 2700 1.08 1.19 3448 2700 748 Qpeak for Case 1= 3.38 cfs 50 3000 0.99 1,09 3488 3000 488 55 3300 0.92 1.01 3546 3300 246 60 3600 0.87 0.96 3641 3600 41 CASE 2 65 3900 0.82 0.90 3703 3900 -197 • 70 4200 0.80 0.88 3877 4200 -323 Case 2 assumes a Time of ConcentraUon less than 5 minutes so that the 75 4500 0.77 0.85 3986 4500 -514 peak flow =.90(4.58)(Imp. Area) = 1.35 cfs 80 4800 0.75 0.83 4131 4800 -669 85 5100 0.72 0.79 4204 5100 -896 ' 90 5400 0.71 0.78 4380 5400 -1020 So, the Peak flow for the Basin is the greater of the two flows, 95 5700 0.69 0.76 4485 5700 -1215 3.38 cfs 100 6000 0.67 0.74 4576 6000 -1424 208' DRAINAGE POND CALCULATIONS Required'208' Storage Volume = Impervious Area x.5 in 112 iNft 594 cu ft . '208' Volume Provided 1469 cu ft DRYWELL REQUIREMENTS - 50 YEAR DESIGN STORM Maximum Storage Required by Bowstring 2208 cu ft Total Storage Provided 1973 cu ft Number and Type of Drywells Required 0 Single ' 1 Double INLAND PACIFIC ENGINEERING r m m m m m m m m m m m m m m m m m m 50-year STORM BOWSTRING METHOD PROJECT: Shelley Lake 2nd Addition PEAK FLOW CALCULATION PROJECT Shelley Lake 2nd Addition DETENTION BASIN DESIGN BASIN: C BASIN C DESIGNER; JEM Tot. Area 1.44 Acres DATE: 03125 Imp. Area 62726 SF C = 0.90 Time Increment (min) 5 CASE 1 Time of Conc. (min) 5,00 Outflow (cfs) 0.3 40 ft. Overland Flow Design Year Flow 50 Area (acres) 1.44 Ct = 0.15 ImpeNious Area (sq ft) 62726 L= 40 ft. 'C' Factor 0.9 n= 0.02 '208' Volume Provided 3669 S= 0.020 Area * C 1.296 Tc = 0.37 min., by Equation 3-2 of Guidelines Time Time Inc. Intens. Q Devel. Vol.ln Vol.Out Storage 1010 ft. Gutter flow (min) (sec) (iNhr) (cfs) (cu ft) (cu ft) (cu ft) Z1= 25.0 5.00 300 4.58 5.94 2386 90 2296 Z2 = 1 n= 0.016 5 300 4.58 5,94 2386 90 2296 S= 0.045 10 600 3.20 4.15 2911 180 ~ 2731 15 900 2.45 3.18 3182 270 2912 d= 0.291 ft. 20 1200 1.95 2.53 3290 360 2930 25 1500 1.62 2.10 3363 450 2913 A R Q Tc Tc total I Qc 30 1800 1.56 2.02 3845 540 3305 35 2100 128 1.66 3653 630 3023 1.10 0.14 5.94 3,12 5.00 4.58 5.94 40 2400 1.19 1.54 3842 720 3122 45 2100 1.08 1.40 3922 810 3112 Qpeak for Case 1= 5.94 cfs 50 3000 . 0.99 1.28 3980 900 3080 ' 55 3300 0,92 1.19 4056 990 3066 60 3600 0.87 1.13 4174 1080 3094 CASE 2 65 3900 0.82 1.06 4253 1170 3083 70 4200 0.80 1.04 4460 1260 3200 Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.77 1.00 4592 1350 3242 peak flow =.90(4.58)(Imp. Area) = 5.94 cfs 80 4800 0.75 0.97 4765 1440 3325 85 5100 0,72 0.93 4854 1530 3324 90 5400 0.71 0.92 5063 1620 3443 So, the Peak flow for the Basin is the greater of the two flows, 95 5700 0.69 0.89 5188 1710 3478 5.94 cfs 100 6000 0.67 0.87 5298 1800 3498 208' DRAINAGE POND CALCULATIONS Required '208' Storage Volume = Imperoious Area x.5 in ! 12 inlft 2614 cu ft . ~ '208' Volume Provided 3669 cu ft DRYWELL REQUIREMENTS - 50 YEAR DESIGN STORM Maximum Storage Required by Bowstring 3325 cu ft ' Total Storage Provided 4928 cu ft Number and Type of Drywells Required 1 Single 0 Double INLAND PACIFIC ENGINEERING r m r m m m rr m m m m m m m m m m m m 50-year STORM BOWSTRING METHOD PROJECT: Sheliey Lake 2nd Addition PEAK FLOW CALCULATION PROJECT Shelley Lake 2nd Addition DETENTION BASIN DESIGN BASIN: D BASIN D DESIGNER: JEM Tot. Area 1.31 Acres DATE: 03125 Imp. Area 8393 SF C = 0,38 Time Increment (min) 5 CASE 1 Time of Conc. (min) 5.00 Outflow (cfs) 1 23 ft. Overland Flow Design Year Flow 50 Area (acres) 1.31 Ct = 0.15 Impervious Area (sq ft) 8393 L= 23 ft. 'C Factor 0.376 n= 0.40 '208' Volume Provided 452 S= 0,020 Area " C 0.493 Tc = 1.84 min., by Equation 3-2 of Guidelines Time Time Inc. intens. Q Devel. Vol.ln Vol.Out Storage 480 ft. Gutter flow (min) (sec) (inlhr) (cfs) (cu ft) (cu ft) (cu ft) Z1 = 50.0 5.00 300 4.56 2.26 907 300 607 Z2 = 3.5 n= 0.016 5 300 4.58 2.26 907 300 607 S= 0.020 10 600. 3.20 1.58 1106 600 506 15 900 ' 2.45 1.21 1209 900 ~ 309 d= 0.179 ft. 20 1200 1.95 0.96 1251 1200 51 25 1500 1.62 0,80 1278 1500 -222 A R Q Tc Tc total I Qc 30 1800 1.56 0.77 1461 1800 -339 35 2100 1.28 0.63 1388 2100 -712 0.86 0.09 2.26 3,04 5.00 4.58 2.26 40 2400 1.19 0.58 1460 2400 •940 45 2700 1.08 0.53 1491 2700 -1209 Qpeak for Case 1= 2.26 cfs 50 3000 0.99 0.49 1513 3000 -1487 55 3300 0.92 0.45 1542 3300 -1758 , 60 3600 0.87 0.43 1586 3600 -2014 CASE 2 65 3900 0.82 0.40 1616 3900 -2284 70 4200 0.80 0.39 1695 4200 -2505 Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.77 0.38 1745 4500 -2755 peak flow =.90(4.58)(Imp. Area) = 0.79 cfs 80 ' 4800 0.75 0.37 1811 4800 -2989 85 5100 0.72 0.35 1845 5100 -3255 90 5400 0.71 0.35 1924 5400 -3476 So, the Peak flow for the Basin is the greater of the two flowg, 95 5700 0.69 0.34 1972 5100 -3728 226 cfs ' 100 6000 0.67 0.33 2014 6000 -3986 208' DRAINAGE POND CALCULATIONS Required'208' Storage Volume = Impervious Area x.5 in ! 12 in/ft 350 cu ft , '208' Volume Provided 452 cu ft DRYWELL REQUIREMENTS - 50 YEAR DESIGN STORM Maximum Storage Required by Bowstring 607 cu ft Total Storage Provided 608 cu ft Number and Type of Drywells Required 0 Single 1 Double INLAND PACIFIC ENGINEERING m m m m s m m m r m m s m m m m m m m 50-year STORM BOWSTRING METH00 PROJECT: Shelley Lake 2nd Addition PEAK FLOW CALCULATION PROJECT Shelley Lake 2nd Addition DETENTION BASIN DESIGN BASIN: E BASIN E OESIGNER: JEM Tot. Area 2.23 Acres DATE: 03125 Imp, Area 7385 SF C = 0.34 Time Increment (min) 5 CASE 1 Time of Canc. (min) 6.75 Outflow (cfs) 2 90 ft. Overland Flow Design Year Flow 50 Area (acres) 2,23 Ct = 0.15 Impervious Area (sq ft) 7385 L= 90 ft. 'C' Factor 0.343 n= 0.40 '208' Volume Pravided 402 S= 0.020 Area * C 0.765 Tc = 4.16 min., by Equation 3-2 of Guidelines Time Time Inc. Intens. Q Devel. Vol.ln Vol.Out Storage 440 ft. Gutter flow (min) (sec) (inlhr) (cfs) (cu ft) (cu ft) (cu ft) Z1= 50.0 6.75 405 3.98 3.04 1651 810 841 Z2 = 3.5 n= 0.016 5 300 4.58 3.50 1408 600 808 S= 0.020 10 600 3.20 2.45 1806 1200 606 15 900 2.45 1.87 1945 1840 ' 145 d= 0.200 ft. 20 1200 1.95 1.49 1995 2400 -405 25 1500 1.62 1.24 2029 3000 -971 A R Q Tc Tc total I Qc 30 1800 1.56 1.19 2312 3600 -1288 35 2100 , 1.28 0.98 2191 4200 -2009 1.07 0.10 3.04 2.59 6,75 3.96 3.04 40 2400 1.19 0.91 2300 4800 -2500 45 2700 1.08 0.83 2344 5400 -3056 Qpeak far Case 1= 3.04 cfs 50 3000 0.99 0.76 2376 6000 -3624 55 3300 0,92 0.70 2419 6600 -4181 60 3600 0.87 0.67 2487 7200 -4713 CASE 2 65 3900 0,82 0.63 2533 7800 -5267 70 4200 0.80 0.61 2654 8400 -5746 Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.77 0.59 2731 9000 -6269 peak flow =.90(4.58)(Imp. Area) = 0.70 cfs 80 4800 0.75 0.57 2833 9600 -6767 85 5100 0.72 0.55 2885 10200 -7315 ' 90 5400 0.71 0.54 3007 10800 -7793 So, the Peak flow for the Basin is the greater of the lwo flows, 95 5700 0.69 0.53 3081 11400 -8319 3.04 cfs 100 6000 0.67 0.51 3145 12000 -8655 208' DRAINAGE POND CALCULATIONS Required'208' Storage Volume = Impervious Area x.5 in 112 in/ft 308 cu ft , '208' Volume Provided 402 cu ft DRYWELL REQUIREMENTS - 50 YEAR DESIGN STORM Maximum Storage Required by Bowstring 841 cu ft ' Total Storage Provided 540 cu ft Number and Type of Drywells Required 0 Single 2 Double INLAND PACIFIC ENGINEERING ~ALySIS C" p ~ 1 m r r ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ m m ~ m m SHELLEY LAKE 2ND ADDITION CURB INLET CALCULATIONS Curb Inlet Depression = 2 in. Standard Curb Inlet Length = 4 ft. Upstream 10 yr. Gutter Roughness Reciprocal Depth Length . Curb Drop Impervious Peak Flow Slope Coeff. Cross slope of Flow Required Pond Station RIL Area c.f.s. S n Z Zln d" Qa1La** Ql(QalLa) Remarks D 12+60 L 8393 1.56 0.0075 0.0160 50 3125 0.18 0.124 12.58 Need 2- 4' and 1- 5' curb inlet " Calculated per Figure 18 of Guidelines Calculated per Figure 16 of Guidelines A 4 foot curb drop with a 6" gutter has a capacity of 4.0 cfs in sump condition. APR-29-1999 14:31 INLAND PACIFIC ENG P.01 i . INLAND PACIFIC ENGiNEERING 747 WEST 7TH AVENUE, SUITE 200 SPOKANE, WA 99204 TELEPHONE: (509) 458-6844 FAX: (509) 458-6844 Fax Transmitta T I , r Date: April 29, 1999 W.O, No.: 99029 To: Spokane County Engineers 1026 W. Broadway Spokane, WA 99260 aitrt: Doug Busko Re: Shelley Lake 2' Additon Transmittal of the Followinq: Temporary Pond `C1' - Calculations and Exhibit ~ , < < < r < < 1 Notes: Doug, The addition of a temporary turn-around on Rotchford DRVe will require the addftion of a temporary pond to coilect and treat the storm water in the vicinity of the turn-around. The enclosed calculations show that Temporary Pond `C1' will provide the necessary '208' treatrnent and storage for the 50-year storm event. Piease review the enclosed material and let me know if you see any problems with this design. If you have any questions, please call. Sincereiy, inland Pacific Engineering 049 John E. McKervey, E.I.T. cc: file APR-29-1999 14:32 INLAND PACIFIC ENG P.02 /pow • . • ~ Sti c //e-I z ct iC e- r-7- .Q,- I-.ff,, v z 9 vra.,-y 100 ~e/ G~ 1' p , Pc- be 0*pA 41' par-oevAd ~ 0•5 ~ Pa..~ ae~,.,. Q w Ag 17 - Bo•cK ~rll 3' Frce:c ~s- . ._zoaG•,--4- ri 4a L ACc4 Qr o[.ctPo4J T rDnq Ca 1 rP r- yi I'1-4 t A' y' . jh c/u~~%n~ bo ~mtvi ~ .Aa = s.o)Z = ?b Fe2 7Z P/V Q - 86 fE= (Ta'X, r) OiV 46 o rw-- ~ -/4 a~=D.133crS M ~ ~~,ve f = W ~3= 3 - 7 Yci3 ~ ~ A - ~ P - ~ p '`9 i ~ Ap~ Po..d bepowi .dna. f s,, etc slopes i4P - 3y'x~c' ,Zo"io r"i~ I (ryp) _ 33; r- ~ Qr = 28 y0 tLLC. 33'/Ik~r)(is c A tea _ Q P` o, o,SG C FS ~ rar~J = Q~ t Q~ - 4- /33 A d.asC D. ci`5 ~ . ~ i n f a n d MEMo D PRoJECT P a c i f i c CALC. ❑ JOB N0. SHEET OF E n g i n e e r i n g ~ MEETINC o BY DATE w.st 707 7th, suite iao Spolcane, WsahingDon 99260 OTHER ❑ CHK`D 8Y DATE APR-29-1999 14:32 INLAND PACIFIC ENG P.03 d • .Weigtited Runoff Coefficient Calculation Project: Shelley Lake 2nd Addition Basin: Temp C1 IPE Job 99029 Total Area (acres): 0.831 Designer: J. McKervey Imp. Area (acres): 0.589 Date: 04129/99 Grass Area (acres): 0.2420 Imp. Area "C": 0.9000 Grass Area "C": 0.15 (Imp. Area)(Imp. "C")= 0.5301 (Grass Area)(Grass pC")= 0.0363 0.8310 0.5664 Weighted "C"= 0.5664 0.681588 0.8310 60WSTRlIdG METHOD PROJECT Shelley Lake 2nd Rddition ~ PEA!( fLOW CALCUlATION PROJECT- Shelley Leke 2nd Additlon OETENTION BASIN DESIGN BASIN: Temporary pond C1 9ASiN: Temporary pand C1 10-Year Design Slarm DESIGNEf J. McKenrey Tot, Area 0.34 Acres DATE; 04129199 Imp, Area 11744 SF A C = 0,75 N Yime IncremeM (min) 5 LD CASE 1 Time oi Conc. (min) 5.00 ~ aumo~(cis) 0,149 . ~ 150 ft. Overland Flow D~sign Year Flo~r 10 Area (acres) 0.338 ~ C1= 0.15 Impelvious Area (sq ft) 11144 A L= 150 ft. 'C' Factor 0,747 W n= 0.02 'ZOB' Volurne Provided 838 N S= 0.015 Area ` C 0.252 Tc = 1.02 min., by EquaUon 3-2 of GuiQellm Time Tirne Inc, lntena. 0 Devet. Volln Vo1.0ut Siorage o (t. Guller flow (min) (sec) (iNhr) (cfs) (cu ft) (ou FI) (cu fl) 0-4 Z Z1= 50.0 For Z2 ~ 5,00 3U0 ~ 3.18 0,80 323 45 278 Z 21= 3.5 Type 6 =1.0 e n= 0.016 Rolled = 3.5 5 300 3.18 0.80 323 44.7 278 .D S= 0.030 6 10 600 2.24 0.57 397 99.4 348 33 15 900 1.77 0.45 448 134.1 314 d= 0.113 ft. 20 1200 1.45 0.31 477 178,8 298 ~ ~ 25 1500 1.21 4.31 489 223.5 266 n A R Q Tc Tc total I QC ~ 30 1800 1,04 0,28 499 288.2 231 Z 35 2100 0.91 0.23 506 312.9 193 M ^ 0,34 r' 0.06 ^ 0.80 ^ 0.00 5,00 3.18 0.80 40 2400 0.112 0.21 518 357,6 160 45 2700 0.74 0.19 524 402.3 121 Qpeak brCase 1= 0.80 cFs 50 3000 0.68 0.17 533 447 86 55 3300 0.64 0,18 550 491.7 58 60 3600 0.61 0,16 570 536,4 34 CASE 2 65 3900 0.60 0,15 606 581.1 25 70 4200 0.58 0.15 630 825.8 4 Case 2 assumes a Tirne of Cancentration less than 5 minutes so lha! Ihe ~ 75 4500 0.56 0.14 651 610.5 -20 peak Aow =.90(3.16)(Imp. Afea) = 0.77 cfs ° t w 80 4600 4.53 0.13 655 715.2 •59 85 5100 0.52 0.13 683 759.9 •77 94 5400 0,50 0.13 695 804,6 -110 ' So, the Peak Cow foc the Basin Is lhe greater of lhe tw4 fl4ws, 95 5700 0,49 0,12 718 649.3 •131 0.80 cts 100 6400 0.48 0.12 740 884 -154 2Q8' DRAINAGE POND GALCULATIONS Required'208' Storage Volume - = Impervious Area x.5 in 112 iNft 489 cu ft 208' Storege Volume Provided 633 cu (t ' DRYWEIL REOUIREMENTS -10 YEAR DESiGN ST01 ~ " Maximum Storage Required by Bowstring 314 cu ft A TalalStorage Provided 1587 cv N . a Number and Type a1 Dryweils Required 0 Singte ERR Oouble 54-year STORM 80WSTRING METHOD PROJECT Sheiley Lake 1nd Add'ition PEAK FIOW CALGULATIflN PROJECT Sheiley lalce 2nd Add(OOn DETENTION BASIN DESIGN BASIN: Temporary pond C1 ' BASIN Temporary pond C1 DESIGNEI JEM 7ot Area 0.83 Aaes DATE: 04129 °3) Irnp. Area 11744 SF ~ C = 0.75 ~ ti Time Incremenl (min) 5 ~ CASE 1 Tfine oi Conc. (min) 5.00 ~ Oulflaw (cts) 0.149 ~ 150 ii, Overland Flaw Qesign Year Flovi 50 ~ Area (acres) 0.831 H Ct = 0.15 Impervlous Area (sq ft) 11144 A W L= 150 ft, 'C Factor 0.747 n= 0,02 '208' Vo1ume Prorvided 638 w S= 0,015 Atea' C 0.621 Tc = 0.89 min., by Eguation 3-2 0l Guidelines T'ine Time fnc. ' Irdens. Q Devel, Vol,ln Vol,Out Staage o tt. Gutter flow (min) (sec) (irtlhr) (cis) (cu ft) (cu k) tcu ft) Y1 50.0 ^ 5.00 ~ 300 4.58 2.84 =1143 r yc 45 1098 rZ' D Z2 = 3.5 . z n= 0.016 5 300 4.58 2.84 1143 44.7 1098 d S= 0,030 10 800 3.20 1.99 1394 89.4 1305 D 15 900 2.45 1.52 1524 134,1 1390 n d= 0.181 ft. ZO 1240 1.95 1,21 1576 178.8 1397 -n 25 1500 1,62 1.01 1611 223.5 1388 ~ A R Q Tc Tctolal I Qc 30 1800 1,59 0.97 1842 268.2 1574 35 ZtUO 1.28 0.79 1750 312.9 1437 m z 0.88 0.09 2.84 0.00 5.00 4,58 2.84 40 2400 1.19 0,14 1840 357.6 1483 0 45 2700 1.08 0.97 1879 402.3 1476 Qpeak for Case 1= 284 cfs ' SO 3000 0,99 0.61 1906 441 1459 55 3300 0,82 0.51 1843 491.7 1451 60 3600 0.87 0.54 1959 538,4 1463 CASE 2 65 3900 0.82 0.51 2037 581.1 1456 70 4200 0.80 0.54 2136 825.6 1511 Gase 2 assumes a Time of Coocentration less than 5 minutes so Ihat the 75 4500 0.77 0.48 2200 670.5 1529 peak flow =.90(4.58)(imp. Area) ~ 1.11 cis , 80 4800 0.75 0.47 2282 715.2 1587 85 5100 0.72 0.45 2325 759.9 1565 90 5400 0.71 0.44 2425 804.6 1620 So, the Peak flow for the 8asin Is the greater ot the two flows, 85 5700 0.69 0.43 2485 849,3 1638 2.84 cfs 100 8000 0.67 0.42 2538 894 1644 206' ORAINAGE PONQ CALCULATIOUS ReQulred'2Q8' Slaage Volume = Imperolous Area x,5 in 112 irlft 489 cu fl '2a8' Volume Provided 638 cu fl DRYUUEII REQUIREMENT5 • 50 YEAR DfSiGN STORM Maximum Storage Requfred by Bowshing 1574 cu f1 Y Tolal Storage Pravided 1587 cu ft ~ Number and Type ol Orywells ftequired 0 Single ERR Double INlANO PA(AFiC ENGINEERINO APR-29-1999 14:34 INLAND PACIFIC ENG P.06 ~ • ` - _ - . ~ ~ ~ ~ i ~ ~ ~ ~~'1` ~~tis~~_ 2 ~.i'~ ~ r 'i•~ ~ /i / / / ~ ~ ~ ~ ~ \ • - ' ~ ' v ~ _ ~i i / ♦ ~11 ~ ~ - ~.i- ~ ~i ~ / ~ / \ ~ ~ - ~ ' le 100 10, ' ' ~e.. - - 2045 - _ ~ y~<<` _ ~ - j~ ~ ~ ♦ ~ r r" - - ~ ol ol~ 6~ L.JI~ . ~ / ~ i i~~i ~ r / / I Ol~ -p BA /J • ~ ~ / O ~ ^TOTAL SIN n~ ~ ' 1---_------ - 8 ~ ~ • A.'~ 1 AGR~S ~ ~ . ♦ ~ ~ ♦ ~ ~ Ba I IMP '2ER :os CR~' ~ 0.19 ACRE _Im~ US 9 0.25 ~RES ~ l / ^ \ ' ou~ O 1 i- fr~-__-__---- ! ~ ~ r ~IN ` ~ 1 _ ` l ~ , ~ ~ / • ~ ~ ~ 1 A `c J . ~ . s , =RVIO t ACRE , -~-~~,PP ~ , o ; / IL_1 J,, ~ ~ ~ ~ • ' 1 ~fJ, 7-Yf~ = Z'•. P. ♦ / ~ ~ ~ ~ `R~UTE , . ~j~ ~ ~ . ` ~ ~ ~ __2O _ ~ _r~-,~ I I ± i 2054 2055 , , . f ~ % ~ V ~V ~11 f / ~ / r_ / 'r 2060 ---rr- r- ~ iY ~ ~ 2Q6~~ ~ • ~ / ~i~ ~ ~ \ ♦ \ \ ~ \ 1 . ~ ~ -T ~ ~ . r . • f ~ ~ > s C' BASIN . L---------~~~--- T~~ ~ l 1•1{l ~ ~ 1 . -1 /1 ( ~ j 1111ji ,~r~ ~ Busko, Doug From: Busko, Doug Sent: Friday, Aprii 23, 1999 9:16 AM To: 'ipe@iea.com' Subject: Susan Murphy: Shelley Lk. 2nd, Comments 1 Susan, • A short note to list the comments you and I discussed on Wednesday: • A turnaround needs to be provided at the south terminus of Rotchford Drive. Please include a legal description and exhibit for this offsite easement. • A typical road cross-section needs to be shown for Lane B. • The 10 and 50 year required pond volumes shown on Page 4 of the drainage report do not correlate with the Bowstring calcs in the appendix. Please clarify how the volumes on Page 4 were determined. • On the sight distance plan sheet, it appears that the stopping sight distance values from the County Road Standards were used as the criteria instead of the intersection sight distance values from AASHTO. Please check on this. Doug Busko, P.E. Spokane County Engineers Page 1 ' r. RECEIVED MAR 3 9 1999 SPOKANE COUNTY ENGINEER S P O K A N E O U N T Y E3UILDING AND PLMfNWG . A DMSION OF THE PUBLIC WO1tKS DEPARTMENT James L. Manson, C.B.O., Director Gary Oberg, Director MEMORANDUM TO: Spokane Coun Division of En ineerin and Roads - Pat Harper pokane County Division of Utilities - Jim Red ~ Spokane County Division of Utilities Stormwater Division - Brenda Sims Spokane Regional Health District - Steve Holderby Spokane County Parks, Recreation and Fair - Steve Horobiowski • Fire Protection District No. 1 Vera Water and Power Central Valley School District #356 FROM: John Pederson, Senior Planner ~ DATE: March 30, 1999 SUBJECT: Proposed Final Plat of Shelley Lake Second Addition PE-1750-94 Enclosed find copies of the above referenced final plat. Please review and forward any comments to me by April 11, 1999. If you have any questions please contact me at 477-3675. Thank you. lsc Enclosure c: applicantlsurveyor 1026 W. BROADWAY • Sl'OKANE, WASHINGTON 99260-0050 PHONE: (509) 477-3675 • FAX: (509) 4774703 • TDD: (509) 3243166 • I-- ~ ~ IN41"1ND PACIFIC EIVGINEERINGf INC. ~ i i ~ ~ ~ _ _ - - - - . ~ I ; ~ I ~ I ' j 4 ~ J r~ ~ ~J ~ , • - • ~ . 7 ~ il i~ .._I RECEIVED y SPOKANE CouN i r' tNGlNEER ~ ~ i ~ ~ ~ SPOKANE • COEU R D'ALENE i . ' DRAINAGE REPORT for Shelley Lake - 2nd Addition Spokane County, Washington ' March,1999 IPE JOB #99029 ' ' Prepared by: Inlarrd Pacific Engineering Company 707 W. 7th Avenue, Suite 200 Spokane, WA 99204 (509)458-6840 ' This report has been prepared by John McKervey, E.I.T. and the staffof Inland Pacific Engineering Company under the direction of the undersigned professional engineer whose seal and signature appear hereon. 4 + • ~ ' 2 ~~f - - Orfq1,~. • F . EXPIRE 24f _ Todd R. Whipple, P.E. Weighted Runoff Coefficient Calculation Project: Shelley Lake 2nd Addition Basin: Temp C1 IPE Job 99029 Total Area (acres): 0.339 Designer: J. McKervey I mp. Area (acres): 0.27 Date: 05/03/99 Grass Area (acres): 0.0690 I mp. Area "C": 0.9000 Grass Area "C": 0.15 (Imp. Area)(Imp. "C")= 0.2430 (Grass Area)(Grass "C")= 0.0104 0.3390 0.2534 Weighted "C"= 0.2534 = 0.747345 0.3390 ~ ' ' DRAINAGE REPORT FOR SHELLEY LAKE - 2n° ADDITION INTRODUCTION Shelley Lake 2nd Addition is part of the Shelley Lake PUD Plat aad is adjacent to that portion of the Shelley La.ke PUD which was included in the original Shelley Lake PUD Plat Drainage Report which , was completed in June, 1996 and approved, Basin P and Basin A-Temp which were part of the ori$inal Shelley Lake PUD drainage report have been incorporated into this report as portions of Basin A and Basin B. Shelley Lake 2' Addition includes 201ots and adjoins the first phase of Shetley Lake at the southwest corner of the first phase. PURPOSE The purpose of this report is to determine the extent of storm drainage facilities which will be re~quired to dispose ofthe increase in stormwater runoffcreated by the development of Shelley Lake 2 Addition. The storm drainage facilities for this project will be designed to dispose of runofffrom ten and fifty year design storms. This development is within the Aquifer Sensitive Area of Spokane County and is subject to `208' requirements. For this project the 10 a.nd 50 year curves from the Spokane, Medical Lake, Rea.rdon, Cheney and Rockford intensity curves were used, as well as the SCS iso-pluvial rainfall curves. Per direction from Spokane County, the SCS curves have been further refined with the NOAA iso-pluvial curves. ANALYSIS METHODOLOGY The Rational Method, which is recommended for basins less than ten acres in size, will be used to determine the peak discharges and runoffvolumes for all basins included in this report. PROJECT DESCRIPTION ' Shelley Lake 2nd Addition includes 201ots of the approved 2621ots and 459 units in the approved preliminary plat and FEIS documents. The Shelley Lake subdivision is located in the North'/z ofthe SE 1/4 of the NE 1/4 of Section 24, T. 25 N., R. 44 E., W.M. within Spokane County, Washington. ' TOPOGR.APHY ~ The general sloPes within this Plat v from nearlY flat within several natural saddles to short slopes ~'Y of up to 20-percent. Generally, the area covered by this report would be characterized as rolling. For development purposes, the natural sloping was used for design and is maintained as possible throughout the project. Inland Pacrfic Engineering 1 Shelley Lake Z"dAddition ' ' SOII..S As can be seen from the accompanying soils map from the Spokane County Soils Survey as performed by the SCS, the site consists of two soil types, both within the Class B type. These soils are GgB and CxmB and are described as follows. , GgB - Garrison gravelly loam, 5 to 20 percent slopes: Sofls witlun this soil type are somewhat excessively drained soils formed in gravelly glacial outwash material from a variety of igneous rock. Surface runoff is slow and the hazard of erosion is sGght. Spokane County Guidelines for Stormwater Manaeement indicate this to be a Soil Group Type B and pre-approved for drywell installation. Hydrologic Soil Classificatfion - B GmB - Garrison very gravelty loam, 0 to 8 percent slopes: This soil is generally the same as the Gamson gravelly loam, with the only difference being that the surface layer is much more stony and contains very little loam if any. Spokane County Guidelines for Stormwater Ma.naQement indicate this to be a Soil Group Type B and per-approved for drywell installation. 1 Hydrologic Soil Classificah'on - B DRAINAGE NARRATIVE , The offsite drainage which flows into Shelley Lake 2"d Addition has been incorporated into the basins included in this drainage report. As Shelley Lake 2nd Addition is located within the Aquifer Sensitive Area of Spokane County, all onsite drainage will be collected and treated using the `208' runoff ' method as described in the Spokane County Guidelines for Stormwater Management. To facilitate this analysis Shelley Lake 2" Addition was divide into 3 basins (A, B and D). The following Table 1 lists the basin details. Table 1- Pond and Basin Summary , Pond and Basin Summary Pond Basin Total Area *Total Impervious Weighted R`208' Impervious ' SF (AC) Area SF (AC) `C' Area SF A A 94,090 (2.16) 311624 (0.73) 0:402 17,625 ' B B 2213286 (5.08) 191689 (0.45) 0.217 14,256 C C 62)726 (1.44) 62)726 (1.44) 0.900 62)726 D D 57,063 (1.31) 17,206 (0.40) 0.376 8,393 E E 97,139 (2.23) 25,003 (0.57) 0.343 7,385 Total Impervious Area includes paved roadway area, 1600 a.f per roof and 600 s.f. per driveway. `208' Impervious Area includes only the paved roadway area. Inland Pacific Engineering 2 Shelley Lake 2"dAddition r ' ' "208 " ~ Caleulations ' Within each basin, the street areas from back of curb to back of curb were calculated to determine the required `208' storage. As shown on the `208' calculation worksheets included, the `208' storage volumes provided are adequate to perform the ` 208' treatment for the first half inch of rainfall. In ' addition to `208' treatment, the enclosed worksheets also show the calculations for the drywell requirements. The `208' storage and drywell requirements for each basin are summarized on the following Table 2. Table 2-`208' Treatment and Drywell Require,nent Summary ' 1 , , . . . , _ 208"Treatment and Drywelt Summary. Pond Basia 1208' Volume *`208' Area Required `208' Area Drywells , Required (CF) - (SF) - Provided Required A A 734 13096 13120 1-Type B B B 594 887 2,192 1-Type B C C 2614 3,901 52476 1-Type B D D 350 452 675 1-Type B ' E E 308 402 600 2-Type B * Based on a`208' storage depth of 8 inches. Side slope volume is not included. Total Stormwater Storage Calculations In addition to the `208' storage requirements, the total stormwater storage for the 10-year design , storm was also considered. Each of the ponds in Shelley Lake 2°d Addition will have the caPacity to contain the required volume for the 10-year design storm. In addition, the SO-year design storm was also exa.mined to determine the amount of overflow expected. This information is summarized in the ' following Table 3. ' y <Y Inland Aacific Ertgineering 3 Shelley Lake ?'JdAddition , Table 3-10-year and SO`year Stormwater Storage Yolume Summary .10-year and 50-year Storage Volume Summary by Bowstring - Pond Basin 10-year 10-year 50-year, 50-year 50-year Volume Volume Volume.: .Volume Volume Required Provided Required'' ~ Provided A (CF) _ L . (CF) (CF) (CF) * (CF) . . A A 953 1,344 13564 11642 +78 B B 098 2,630 22208 2,954 +746 C C 3,461 62571 5,496 7,323 +1,827 D D 339 810 607 1,056 +449 E E 369 720 841 958 +117 * SO-year Volume Provided includES side slape volume As can be seen in Table 3 all of the ponds will contain the 10-year and 50-year design storms. Curb Drop/Inlet Analysis ' The inlet for Pond D is on grade and therefore a curb drop analysis was performed for this pond. The analysis shows that the pond requires 12.58 feet of curb drop opening, therefore 2- 4' inlets and 1- 5' inlet will be used to capture the stormwater for this pond. The inlets for the remaining ponds are in sump condition. ' ~ ~ Inland Pacifrc Engineering 4 Shelley Lake 2"dAddition ~ ~ ~ ~ I ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~w r~ ~w r ~ r r FIGUR-ES ~ l ■ VIJp,SHiNGTON ~P~,NE C{~uNT~t ~ ~4 R. 4G ~ E~ ~ : iR • 4' ~ _ . G . z'•; . . ~ p P • - ;y ~ - ~ ' ' . ~ . , ~ ~ ' 1 : ` ~ ~~a ' • _ Gg*,; ` • A N p Y ~ ~ ~ ~ ~ • ~ ~ , i . F y ~ ` ~ s, S.,T. Pql)L ` ? , r • ' 'S` ;AUKEE dttl~ s G r~, F3 ` ~ ~ . . . ± . - , ~ - - ~ a, . ~ f ` , ~ ~ y ~ ~ _ 't a~~l;•. s. , 1r• z . ~ t t~. ~ . . fsi • q.~ f~ C ~ C`{y, 3 t~~r a 1.4 M E~ ~ 8 l/1~ m ~ ~ ~ . ~ t 3'st';~~c:-{ • y ~,-a. , ' ft . G gA ~ •:tr ~ ~t~ t; ,~.,`l±-'~ Y ~ ~ ~ pE'- A `t ~ ~ r' 24 ; ' ~ ~ \ :in_ +y 4 ~ r' r , G~,iE? psA f;`~r.....,,,i`=•~.~,`~. ~ ~ ~ r {r,I;Ok'- I ~ / ~ r'•~ x`4 ` °~j ~ y~- F-{ ~ [3 S g - : ~ P ROJEGT - '~I ~~N :r_ ro 6 ~ ~ OcAT P5A P$A . ri., ' ~ e~~} ~ -r ~ • . - - ~ tif~ ~ • ~~+~f~~ ~ ~•3 ~ ~ ~Y v4e f 1 ( .~•a.' C UB i'. ' ' . „ . ~C Y`_•: +r.. . ~j 1=~1~~ ~'~t~ . . ~•v:~ ~ ~r, s Zt. < G gA ' 13tt3 g a E3 . ~ i ` 3 taB ~F-► tB - 1 Cn T3 h ,To g Ps ~C HA - I Appl~Cl~r ~ ~LL~Y L H 400 INL AND S o! P r . I boow t-A-.0-411,121COVRING , , qNLS ~ p` - • • • • • ~ a . ' - ~ ~ i • i ~ LvJO - ~ Q p n a ~;4 1~:~'=JJ`.:" ' 1f - i ' • ~ • 11' M• .~J ~ • • ~y~ ~ • • ~ • • ~ p t O• • tK"' ~ • • ~1.• • O ~ • • Y~~~ • • O • , ~ • • ~ ~i }•4~'~ O • • D r 0 ~ • ~ • ~ ~ C• ~ i ~ • O p 203? p ~ ~ • ° ~ ' t • • rOgCess',_. Ctil ~ . . ~ . . . . . . G`~.~.~.'~.M`.• • p ~ ~ 00 0 ~p • • • s~~~ • a~~ ~ D ~t'+~•," ~ • • O ~ O a • • • r~~ s•• .r • . , • .4 .';:.::~29 t~ • • • ~~-~wi WAY • •~on~• : ~ : Q I i • Q ~ : :i i:• i • • • ~ • • o 0 : • J r ~D 5Ch ~ • o ■ ?4.LLEY ' o o • ~ : : a . • . . ~ • O • 5 O• • ;r ~ r i • ~r • • ~ ~ ' ~ . ~ ° . ` • . 7ll~ , . • Veradale • - _ • , • • ~ • • - 1 4 LANE.~ . ~ • ~ •h ~ • O ~U~• • • ~ ~ ~ ~ ~ ~ / r ~ , ~ s • • • • • ~ ~~y • • . 0 ' . , ~ • II • 7~ L~. a ` ----`.:r • ~ • . ~ • ~ ~ ~ ' ~ ` • a df u0 pAClFIC,_ • 1 ~l- • n ~ ~ o • ~ S T PA U L & -V era ~ . Gravel Pitx . ~ U Trale~ = ' AvE ~f r Park . . • , + Q~ • • _ _ , 4TH . •i..{ ~ _ \ ' ~f• . . . . . . :l ~:.y ~ ~ n ~ ~ ~ - . - - o . ~ , . e1~ ~ . . ~,1, ~ ~ ~ - . ~ 1~~ ~ ~Ir= ~ ~ ~ ~ . ' • ~ s , Or` ~ ~ _ ~ ~ ; ~1 • . ~ , ,7o 4 i seW~ Po;sp • ~ ~ =~p ds - _ ccnLr;►l . . ~ _ : ~ itikh 5ch ~ , ; , , 0 e6 ~ •;1, • . It ~ ~ - - i ~ ~ ' - . ~ aypit1ly'. ~ P RO, . LOC r k y _ ~ Av E S ~ 1 • ~ l,f~ i / i Z o,:: . /i ~ • t ~ l /xI ~..t . •,fl ' ~ . V) NoT To scaLE . ~ ~ -VON INl-AND SH ELLEY LAKE 2Np p,DD1TIQN ~ PACIFIC IN~ ~ AP oaTE: 03/, ENGINEER ICI I TY - . . _ c,~~tA 2d4 (509) 458-6840 ~ - .FSt_(',844 , WEIGHTED `C' FA CTQRS 1 1 ' I , i Weighted Runoff Coefficient Calculation ~ Project: Shelley Lake 2nd Addition Basin: A I PE Job 99029 Total Area (acres: 2.16 Designei J. McKervey Imp. Area (acres) 0.726 Date: 03/25/99 Grass Area (acre: 1.4340 Imp. Area "C": 0.9000 Grass Area "C": 0.15 (Imp. Area)(Imp. "C")= 0.6534 (Grass Area)(Grass "C")= 0.2151 2.1600 0.8685 Weighted "C"= 0.8685 0.4021 2.1600 / ' Weighted Runoff Coefficient Calculation ' Project: Shelley Lake 2nd Addition Basin: B IPE Job- 99029 Total Area (acres 5.08 Designei J. McKervey ' Imp. Area (acres) 0.452 Date: 03/15/99 Grass Area (acre: 4.6280 Imp. Area "C": 0.9000 ' Grass Area "C": 0.15 (Imp. Area)(Imp. "C")= 0.4068 (Grass Area)(Grass "C")= 0.6942 5.0800 1.1010 ' Weighted "C"= 1.1010 0.2167 5.0800 1 ' ' ' 1 ' Weighted Runoff Coefficient Calculation Project: Shelley Lake 2nd Addition • Basin: C I PE Job 99029 Total Area (acres): 9.21 Designer: J. McKervey ' Imp. Area (acres): 1.44 Date: 03/25/99 Grass Area (acres): 7.7700 imp. Area "C": 0.9000 ' Grass Area "C": 0.15 (Imp. Area)(Imp. "C")= 1.2960 (Grass Area)(Grass "C")= 1.1655 9.2100 2.4615 ' Weighted "C"= 2.4615 0.267264 9.2100 ' ' . ' . ~ Weighted Runoff Coefficient Calculation ' Project: Shelley Lake 2nd Addition Basin: D I PE Job 99029 Total Area (acres 1.31 Designei J. McKervey ' I mp. Area (acres) 0.395 Date: 03/25/99 Grass Area (acre: 0.9150 Imp. Area "C": 0.9000 Grass Area "C": 0.15 ' (Imp. Area)(Imp. "C")= 0.3555 (Grass Area)(Grass "C")= 0.1373 1.3100 0.4928 Weighted "C"= 0.4928 0.3761 1.3100 ' ' ~ ' / Weighted Runoff Coefficient Calculation Project: Shelley Lake 2nd Addition Basin: E IPE Job 99029 • Total Area (acres' 2.23 Designei J. McKervey Imp. Area (acres) 0.574 Date: 03/25/99 Grass Area (acre: 1.6560 Imp. Area "C": 0.9000 ' Grass Area "C": 0.15 (Imp. Area)(Imp. "C")= 0.5166 (Grass Area)(Grass "C")= 0.2484 2.2300 0.7650 ' Weighted "C"= 0.7650 0.343 2.2300 ' ' ' ' 1 ~ 13QW T ING CALCULATIDNS 1 BOWSTRING METHOD PROJECT Shelley Lake 2nd Addition PEAK FLOW CALCULATION PROJECT Shelley Lake 2nd Addition DETENTION BASIN DESIGN BASIN; A BASIN: A 10-Year Design Storm DESIGNEf J. McKervey Tot. Area 2.16 Acres DATE: 04l21/99 Imp. Area 17625 SF C = 0.40 Time Increment (min) 5 CASE 1 Time ot Conc. (min) 9.24 Oufflow (cfs) 1 76 (i. Overland Flow Design Year Flow 10 Area (acres) 2.16 Ct = 0.15 Impervious Area (sq ft) 11625 L= 76 fl. 'C' Factor 0.402 n= 0.40 '208' Volume Provided 750 S= 0,030 Area ' C 0.868 Tc = 3.33 min., by Equation 3-2 of Guidelines ` Time Time Inc. Intens. Q Devel. Vol.ln Vol.Out Storage 700 ft. Gutter flow (min) (sec) (in/hr) (cfs) (cu ft) (cu ft) (cu ft) Z1 = 50.0 For Z2 9.24 554 2.34 2.03 1507 554 953 Z2 = 3.5 Type B =1.0 r, = 0.016 Rolled = 3.5 5 300 3.18 2.76 1110 300 810 S= 0.010 10 600 2.24 1.95 1534 600 934 4 15 900 1.17 1.54 1673 900 773 d= 0.196 ft. 20 1200 1.45 1.26 1748 1200 548 ~ 25 1500 1.21 1.05 1774 1500 274 A R Q TcTc total I____ Qc__ , , 30 1800 1.04 0.90 1796 1800 -4 ' 35 2100 0.91 0.79 1808 2100 -292 13 Q 10 2.03 5.91 9.24 2.34 2.03 40 2400 0.82 0.71 1843 2400 -557 45 2700 0.74 0.64 1856 2700 -844 G;)e,3k tc~~ CaSe 1= 2.03 r.fs l `yr 50 3000 0.68 0.59 1883 3000 -1117 55 3300 0.64 0.56 1939 3300 -1361 60 3600 0.61 0.53 2007 3600 -1593 CASE 2 ~ 65 3900 0.60 0,52 2130 3900 -1770 70 4200 0.58 0.50 2210 4200 -1990 Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.56 0.49 2280 4540 -2220 80 4800 0.53 0.46 2296 4800 -2504 peak flow =.90(3.18)(Imp. Area) = 1.16 cfs 85 5100 0.52 0.45 2388 5100 -2712 90 5400 0.50 0.43 2426 5400 -2974 So, the Peak flow for the Basin is the greater of the two flows, 95 5700 0.49 0.43 2505 5700 -3195 2.03 cfs 100 6000 0.48 0.42 2579 6000 -3421 208' DRAINAGE POND CALCULATIONS Required'208' Storage Volume = Impervious Area x.5 in I 12 iNft 734 cu ft 208' Storage Volume Provided 750 cu ft DRYWELL REQUIREMENTS -10 YEAR DESIGN STO Maximum Storage Required by Bowstring 953 cu ft Total Storage Provided 1344 cu ft Number and Type of Drywells Required 0 Single 1 Double ~ ~ ~r r ~ ~ ~ ~ ~ ~ ~ ~ ~■r ~ ~ ~ r ~ ~ BOWSTRING METHOD PROJECT: Shelley Lake 2nd Atldition PEAK FLOW CALCULATION PROJECT Shelley Lake 2nd Addition DETENTION BASIN DESIGN BASIN: B BASIN: B 10-Year Design Storm DESIGNER; J. McKervey Tot. Area 5.08 Acres DATE: 04121/99 Imp. Area 14256 SF C = 0.22 Time Increment (min) 5 CASE 1 Time of Conc. (min) 9.10 Outflow (cfs) 1 680 ft. Overland Flow Design Year Flow 10 Area (acres) 5.08 Ct = 0.15 Impervious Area (sq ft) 14256 L= 680 ft. 'C Factor 0.22 n= 0.40 4'•i'208' Volume Provided 1469 S= 0.100 Area ' C 1.118 Tc = 8.65 min., by Equation 3-2 of Guidelines ~ Time Time Inc. Intens. Q Devel. Vol.ln Vol.Out Storage 200 ft. Gutter flow (min) (sec) (iNhr) (cfs) (cu ft) (cu ft) (cu ft) Z1 = 50.0 For Z2 9.70 582 2.27 2.54 1980 582 1398 Z2 = 3.5 Type B=1.0 n= 0.016 Rolled = 3.5 5 300 3.18 3.55 1429 300 1129 S= 0.030 10 600 2.24 2.50 1998 600 1398 15 900 1,77 1.98 2172 900 1272 d- 0.174 ft. 20 1200 1.45 1.62 2265 1200 1065 25 1500 1.21 1.35 2296 1500 796 A R Q Tc Tc total I Qc ~ 30 1800 1.04 1.16 2322 1800 522 35 2100 0.91 1.02 2337 2100 237 0.81 0.09 2.54 1,06 9.70 2.27 2.54.` ' 40 2400 0.82 0.92 2381 2400 -19 45 2700 0.74 0.83 2397 2700 -303 ' Qpeak for Case 1= 2.54 cfs 50 3000 0.68 0.76 2430 3000 -570 L 55 3300 0.64 0.72 2502 3300 -798 60 3600 0.61 0.68 2589 3600 -1011 CASF 2 65 3900 0.60 0.67 2748 3900 -1152 70 4200 0.58 0.65 2851 4200 -1349 Case 2 assumes a Time of Concentration less lhan 5 minutes so that the 15 4500 0.56 0,63 2940 4500 -1560 peak flr,t, _ 90(3 18)(Imp. Area) = 0.94 cfs 80 4800 0.53 0.59 2960 4800 -1840 85 5100 0.52 0.58 3079 5100 -2021 `90 5400 0.50 0.56 3128 5400 -2272 S:), lhc Peak flow for fhe Basin is lhe grealer of ihe lwo flows, , 95 5700 0.49 0.55 3230 5700 -2470 , 2.54 cls 100 6000 0.48 0.54 3325 6000 •2675 208' DRAINAGE POND CALCULATIONS Required'208' Storage Volume = Imperoious Area x.5 in 112 inlft 594 cu ft 208' Storage Volume Provitled 1469 cu ft DRYWELL REQUIREMENTS -10 YEAR DESIGN STORi Maximum Storage Required by Bowstring 1398 cu ft Total Storage Provided 2630 cu ft Number and Type of Drywells Required 0 Single 1 Double BOWSTRING METHOD PROJECT: Shelley Lake 2nd Addition I'L-AK FLOW CALCULATION PROJECT Shelley Lake 2nd Addition DETENTION BASIN DESIGN BASIN: C BASIN: C 10-Year Design Storm DESIGNER: J. McKervey Tot. Area 9.21 Acres DATE: 04121l99 Imp Area 62726 SF C- 0L7 Time Increment (min) 5 ChSE 1 Time of Conc. (min) 5.00 Outflow (cfs) 1 300 ft. Overland Flow Design Year Flow 10 Area (acres) 9.21 Ct = 0.15 Impervious Area (sq ft) 62726 L= 300 ft. 'C Factor 0.267 n= 0,02 '208' Volume Provided 3669 S= 0A20 Area " C 2.459 Tc = 1.24 min., by Equation 3-2 of Guidelines ~Time Time Inc. Intens. Q Devel. Vol.in Vol.Out Storage 1050 ft. Gutter flow (min) (sec) (inlhr) (cfs) (cu ft) (cu ft) (cu ft) Z1 = 25.0 ForZ2 5.00 300 3.18 7.82 3144 300 2844 Z2 = 1 Type B =1.0 n= 0.016 Rolled = 3.5 S 300 3.18 7.82 3144 300 2844 S= 0.045 10 600 2.24 5.51 3867 600 3267 15 900 1.77 4.35 4361 900 3461 d= 0.322 ft, 20 1200 1.45 3.57 4642 1200 3442 25 1500 1.21 2.98 4767 1500 3267 A R Q Tc Tc total I Qc 30 1800 1.04 2.56 4864 1800 3064 ~,R 35 2100 0.91 2.24 4928 2100 2828 1.35 0.16 7.82 3.02 5.00 3.18 7.82 40 2400 0.82 2.02 5045 2400 2645 ' 45 2700 0.74 1.82 5099 2700 2399 Qpeak for Case 1= 7.82 cfs 7 " 50 3000 0.68 1.67 5187 3000 2187 55 3300 0.64 1.57 5354 3300 2054 60 3600 0.61 1.50 5553 3600 1953 CASE 1 65 3900 0.60 1.48 5905 3900 2005 70 4200 0.58 1.43 6136 4200 1936 Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.56 1.38 6337 4500 1837 peak flat~ =.90(3.18)(Imp. Area) = 4.12 cfs 80 4800 0.53 1.30 6389 4800 1589 85 5100 0.52 1.28 6652 5100 1552 90 5400 0.54 1.23 6765 5400 1365 ihe Peak flow for lhe Basin is the greater of the two flows, 95 5700 0.49 1.20 6991 5700 1291 7 82 cfs 100 6000 0.48 1.18 7203 6000 1203 208' DRAINAGE POND CALCULATIONS Required '208' Storage Volume = Impervious Area x.5 in 112 inlft 2614 cu ft 208' Slorage Volume Provided 3669 cu ft DRYWELL REQUIREMENTS -10 YEAR DESIGN STORM Maximum Storage Required by Bowstring 3461 cu ft Total Storage Provided 6571 cu ft Number and Type of Drywells Required 0 Single 1 Double BOWSTRING METHOD PROJECT: Shelley Lake 2nd Addition PEAK FLOW CALCULATION PROJECT Shelley Lake 2nd Addition DETENTION BASIN DESIGN BASIN: D BASIN: D 10-Year Design Storm DESIGNER: J. McKervey Tot Area 1.31 Acres DATE: 04121199 Imp. Area 8393 SF C = 0.38 Time Increment (min) 5 CASE 1 Time of Conc. (min) 5.17 Outflow (cfs) 1 23 ft, Overland Fla~v Design Year Flow 10 Area (acres) 1.31 Cc = 0.15 Impervious Area (sq ft) 8393 L= 23 ft. 'C' Factor 0.38 n= 0.40 '208' Volume Provided 452 S= 0.020 Area ' C 0.498 Tc = 1.84 min., by EGuation 3-2 of Guidellnes Time Time Inc. Inlens. Q Devel. Vol.ln Vol.Oui Storage 48~-'[ ft Guttcr fIow (min) (sec) (inlhr) (cfs) (cu ft) (cu ft) (cu ft) Z1 = 50.0 For Z2 5.17 310 3.14 1.56 649 310 339 < Z2 = 3.5 Type B =1.0 n= 0.016 Rolled = 3.5 5 300 3.18 1.58 636 300 336 S= 0.020 10 600 2.24 1.12 787 600 187 15 900 1.77 0.88 886 900 -14 d= 0.156 ft. 20 1200 1.45 0.72 942 1200 -258 25 1500 1.21 0.60 967 1500 -533 A R Q Tc Tc total I Qc 30 1800 1.04 0.52 986 1800 -814 ~ 35 2100 0.91 0.45 999 2100 -1101 0.65 0.08 1.56 3.33 5.17 3.14 1.56 40 2400 0.82 0.41 1023 2400 -1377 45 2700 0.74 0.37 1033 2700 -1667 Qpeak for Case 1= 1.56 cfs 50 3000 0.68 0.34 1051 3000 -1949 55 3300 0.64 0.32 1085 3300 -2215 60 3600 0.61 0.30 1125 3600 -2475 CASL 2 65 3900 0.60 0.30 1196 3900 -2704 70 4200 0.58 0.29 1243 4200 -2957 Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.56 0.28 1284 4500 -3216 peak flow = 90(3.18)(Imp. Area) = 0,55 cfs 80 4800 0.53 0.26 1294 4800 -3506 85 5100 0.52 0.26 1347 5100 -3753 90 5400 0.50 025 1370 5400 -4030 So, lhe Peak f ow for the Basin is the grealer of lhe iwo flows, 95 5700 0.49 0.24 1416 5700 -4284 100 6000 0.48 0.24 1459 6000 -4541 208' DRAINAGE POND CALCULATIONS Required'208' Storage Volume = Impervious Area x.5 in ! 12 inlft 350 cu it 208' Storage Volume Provided 452 cu ft DRYWELL REQUIREMENTS -10 YEAR DESIGN STOR~ Maximum Storage Required by Bowstring 339 cu ft Total Storage Provided 810 cu ft Number and Type of Drywells Required 0 Single 1 Double BOWSTRING METHOD PROJECT: Shelley Lake 2nd Addition PEAK FLOW CALCULATION PROJECT Shelley Lake 2nd Adtlition DETENTION BASIN DESIGN BASIN: E BASIN: E 10-Year Design Storm DESIGNER: J. McKervey Tol. Area 2.23 Acres DATE: 04/21199 Imp Area 7385 SF C = 0.34 Time Increment (min) 5 CASE 1 Time of Conc. (min) 7.03 Outflow (cfs) 2 90 ft. Overland Flow Design Year Flow 10 Area (acres) 2.23 Ct = 0.15 Impervious Area (sq ft) 1385 L= 90 ft 'C Factor 0.34 n= 0.40 '208' Volume Provided 402 S= 0.020 Area ' C 0.758 Tc = 4,16 min., by Equation 3-2 of Guidelines Time Time Inc, Intens. Q Devel. Vol.ln Vol.Out Storage 44o T GL,ccPr tlov., (min) (sec) (iNhr) (cfs) (cu ft) (cu ft) (cu ft) Z1 = 50.0 For Z2 7.03 422 2.68 2.03 1146 843 303 Z? = 3.5 Type B 1.0 , . n= 0.016 Rolled = 3.5 . 5 300 3.18 2.41 969 600 369 S= 0.020 10 600 2.24 1.70 1263 1200 63 r 15 900 1.77 1.34 1400 1800 -400 d 0.172 ft 20 1200 1.45 1.10 1477 2400 -923 25 1500 1.21 0.92 1508 3000 -1492 A R Q Tc Tc total I Qc 30 1800 1.04 0.79 1532 3600 -2068 35 2100 0.91 0.69 1548 4200 -2652 0.79 0.09 2.03 2.86 7.03 2.68 2.03 40 2400 0.82 0.62 1581 4800 -3219 45 2700 0.74 0.56 1595 5400 -3805 Qpeak for Case 1= 2.03 cfs 50 3000 0.68 0.52 1621 6000 -4379 55 3300 0.64 0.49 1671 6600 -4929 60 3600 0.61 0.46 1731 7200 -5469 CASE 2 65 3900 0.60 0.45 1839 7800 -5961 411.4 70 4200 0.58 0.44 1910 8400 -6490 Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.56 0.42 1972 9000 -7028 peak flow =.90(3.18)(Imp. Area) 0.49 cfs 80 4800 0.53 0.40 1986 9600 -7614 85 5100 0.52 0.39 2067 10200 •8133 90 5400 0.50 0.38 2101 10800 -8699 So, the Peak flotiv for the Basin is the greaier of the two flows, 95 5700 0,49 0.37 2171 11400 -9229 2 03 cfs 100 6000 0.48 0.36 2236 12000 -9764 208' DRAINAGE POND CALCULATIONS Required'208' Storage Volume = Impervious Area x.5 in I 12 inlft 308 cu ft 208' Storage Volume Provided 402 cu ft DRYWELL REQUIREMENTS -10 YEAR DESIGN STORI Maximum Storage Required by Bowstring 369 cu ft Total Storage Provided 720 cu ft Number and Type of Drywells Required 0 Single 2 Double m m m m m m m m m m m m m m m m m m m 50-year STORM BOWSTRING METHOD PROJECT Shelley Lake 2nd Addition PEAK FLOW CALCULATION PROJECT Shelley Lake 2nd Addition DETENTION BASIN DESIGN BASIN: A BASIN A DESIGNEIJEM Tot. Area 2.16 Acres DATE: 04121 Imp. Area 17625 SF C = 0.40 Time Increment (min) 5 CASE 1 Time of Conc. (min) 8.76 Outflow (cfs) 1 76 ft. Overland Flow Design Year Flow 50 Area (acres) 2.16 Ct = 0.15 Impervious Area (sq ft) 17625 L= 76 ft. 'C' Factor 0,402 n= 0.40 '208' Volume Provided 750 S= 0.030 Area " C 0.868 Tc = 3.33 min., by Equation 3-2 of Guidelines Time Time Inc. Intens. Q Devel. Vol.ln Vol.Out Storage 700 ft. Gutter flow (min) (sec) (iNhr) fcfs) (cu ft) (cu ft) (cu ft) Z1 = 50.0 8.76 525 3.28 2.85 2008 525 1482 Z2 = 3.5 n= 0.016 5 300 4,58 3.98 1599 300 1299 S= 0.010 10 600 3.20 2.78 2164 600 1564 15 900 2.45 2.13 2295 900 1395 d= 0.223 ft. 20 1200 1.95 1.69 2334 1200 1134 25 1500 1.62 1.41 2361 1500 861 A R Q Tc Tc total I Qc 30 1800 1.56 1.35 2680 1800 880 - - , , 35 2100 1.28 1.11 2533 2100 433 ' 33 0.11 2.85 5.42 8.76 328 2.85 40 2400 1.19 1,03 2653 2400 253 45 2700 1.08 0.94 2700 2700 -0 for Case 1= 2.85 cfs 50 3040 0.99 0.86 2732 3000 -268 55 3300 0.92 0,80 2779 3300 -521 60 3600 0.87 0.76 2855 3600 -745 CASE 2 65 3900 0.82 0.71 2904 3900 -996 70 4200 0.80 0.69 3042 4200 -1158 Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.77 0.67 3128 4500 -1372 peak flow =.90(4.58)(Imp. Area) = 1.67 cfs 80 4800 0.75 0.65 3242 4800 •1558 85 5100 0.72 0.63 3300 5100 -1800 ' 90 5400 0.71 0.62 3439 5400 -1961 So, ihe Peak flow for che Basin is the greater of the two Oows, - 95 5700 0.69 0.60 3522 5700 -2178 2.85 cfs ; 100 6000 0.67 0.58 3595 6000 -2405 208' DRAINAGE POND CALCULATIONS Required '208' Storage Volume = Impervious Area x.5 in I 12 inlft 734 cu ft '208' Volume Provided 750 cu ft DRYWELL REQUIREMENTS - 50 YEAR DESIGN STORM Maximum Storage Required by Bowstring 1564 cu ft Total Storage Provided 1642 cu ft Number antl Type of Drywells Required 0 Single 1 Double E~.",iNFERi°AC, 50-year STORM BOWSTRING METHOD PROJECT Shelley Lake 2nd Addilion PEAK FLOW CALCULATION PROJECT Shelley Lake 2nd Addition DETENTION BASIN DESIGN BASIN: B BASIN B DESIGNEIJEM Tot. Area 5.08 Acres DATE: 04121 Inip ,Area 14256 SF C = 0.22 . Time Increment (min) 5 C~~SE 1 Time of Conc, (min) 9.61 Outflow (cfs) 1 ~-)80 ft Overland Flow Design Year Flow 50 Area (acres) 5.08 Ct = 0.15 Impervious Area (sq ft) 14255.67 L= 680 ft. 'C' Factor 0.217 n= 0,40 '208' Volume Provided 1469 S= 0.100 Area ' C 1.102 Tc = 8.65 min., by Equation 3-2 of Guidelines ETime Time Inc. Intens. Q Devel. Vol.ln Vol.Out Storage 200 ft Gutter flow ` (min) (sec) (in/hr) (cfs) (cu ft) (cu ft) (cu ft) Z1 = 50.0 9.61 577 3.07 3.38 2613 577 2036 Z2 = 3.5 ___..__..W n= 0.016 5 300 4.58 5.05 2030 300 1130 S= 0.030 10 600 3.20 3.53 2808 600 2208 ~ 15 900 2.45 270 2960 900 2060 d= 0,198 ft. 20 1200 1.95 2,15 3001 1200 1801 25 1500 1.62 1.79 3029 1500 1529 A R Q Tc Tc total I Qc 7 30 1800 1.56 1.72 3433 1800 1633 ' • 35 2100 1.28 1.41 3240 2100 1140 1 05 0.10 3.62 0.97 9.61 3.07 3.38 40 2400 1.19 1.31 3391 2400 991 45 2700 1.08 1.19 3448 2700 748 Qpea,~ for Case 1= 3.38 cfs 50 3000 0.99 1.09 3488 3000 488 ~ 55 3300 0.92 1.01 3546 3300 246 60 3600 0.87 0.96 3641 3600 41 ChSE ~ 65 3900 0.82 0.90 3703 3900 -197 70 4200 0.80 0.88 3877 4200 -323 Case 2 assumes a Time of Concentratian less than 5 minutes so that the 75 4500 0.77 0.85 3986 4500 -514 peak flow =.90(4.58)(Imp. Area) = 1.35 cfs ` 80 4800 0.75 0.83 4131 4800 -669 85 5100 0.72 0.79 4204 5100 -896 90 5400 0.71 0.78 4380 5400 -1020 So, Ihe Peak flow for ihe Basin is the greater of the cwo flows, 95 5700 0.69 0.76 4485 5700 -1215 , ~.?S cfs 100 6000 0.67 0.74 4576 6000 -1424 . 208' DRAINAGE POND CALCULATIONS Required '208' Storage Volume Impervious Area x.5 in ! 12 inlft 594 cu ft '208' VoIume Provided 1469 cu ft DRYWELL REQUIREMENTS - 50 YEAR DESIGN STORM Maximum Storage Required by Bowstring 2208 cu ft Total Storage Provided 2954 cu ft Number and Type o( Drywells Required 0 Single 1 Double m m m m m m m m m m m m m m m m m m m 50•year STORM BOWSTRING METHOD PROJECT: Shelley Lake 2nd Addition PEAK FLOW CALCULATION PROJECT Shelley Lake 2nd Addition DETENTION BASIN DESIGN BASIN: C BASIN C DESIGNER: JEM Tot. Area 9.21 Acres DATE: 04121 Imp. Area 62726 SF C = 0,27 Time Increment (min) 5 CASE 1 Time of Conc. (min) 5.00 Outflow (cfs) 1 300 ft. Overland Flow Design Year Flow 50 Area (acres) 9.21 Ct = 0,15 :Impervious Area (sq ft) 62726 L= 300 ft. 'C Factor 0.267 n= 0.02 'V >'208' Volume Provided 3669 S= 0.020 Area " C 2.459 Tc = 1.24 min., by Equation 3-2 of Guidelines ~ Time Time Inc. Intens. Q Devel. Vol.ln Vol,Out Storage 1050 ft Gutter flow (min) (sec) (iNhr) (cfs) (cu ft) (cu ft) (cu ft) Z1 = 25.0 5.00 300 4.58 1126 4528 300 4228 Z2 = 1 n= 0.016 5 300 4.58 11.26 4528 300 4228 S= 0.045 10 600 3.20 7.87 5524 600 4924 15 940 2,45 6.02 6037 900 5137 d= 0.370 ft. ' 20 1200 1.95 4.80 6243 1200 5043 25 1500 1.62 3.98 6382 1500 4882 A R Q Tc Tc total I Qc 30 1800 1.56 3.84 7296 1800 5496 35 2100 1.28 3.15 6931 2100 4831 1 78 0.18 11.26 2 76 5.00 4.58 11.26 40 2400 1.19 2.91 7291 2400 4891 45 2700 1.08 2.66 7442 2700 474,1 (,~En:;,~ tu! Ga;e 1= 11.2E cfs 50 3000 0.99 2.43 7552 3000 4552 55 3300 0.92 2.26 7696 3300 4396 60 3600 0.87 2.14 7920 3600 4320 CASE 12 65 3900 0.82 2.02 8070 3900 4170 70 4200 0.80 1.97 8463 4200 4263 c;ase 2 assumes a Time of Concentration less lhan 5 minutes so that Ihe 75 4500 0.77 1.89 8714 4500 4214 flow =.~,0(4 S8NImp Area) = 5 94 cf; 80 4800 0.75 1.84 9041 4800 4241 85 5100 0.72 1.77 9210 5100 4110 90 5400 0.71 1.75 9606 5400 4206 :ha{'r~iE. flrm, for'hi, R:rdn i,; Iltc ()I thc Iwo~ Ilnw!~, 95 5700 0.69 1.70 9845 5700 4145 100 6000 0.e7 1.65 10054 6000 4054 208' DRAINAGE POND CALCULATIONS Required'208' Storage Volume Impervious Area x.5 in ! 12 Inift 2614 cu ft s;~~,•j,.'`iF~.s t: '208' Volume Provided 3669 cu ft DRYWELL REQUIREMENTS - 50 YEAR DESIGN STORM ` Maximum Storage Required by Bowstring 5496 cu ft Total Storage Provided 7323 cu ft Number and Type of Drywells Required 0 Single 1 Double ir, ,°,ND PnCTic eNGiNEERiNG m m m M m m m m m m m m m m m m m m m 50-year STORM BOWSTRING METHOD PROJECT: Shelley Lake 2nd Addition PEAK FLOW CALCULATION PROJECT Shelley Lake 2nd Addition DETENTION BASIN DESIGN BASIN: D BASIN D DESIGNER: JEM Tot. Area 1.31 Acres DATE; 04121 Imp. Area 8393 SF C = 0.38 ~ Time Increment (min) 5 CASE 1 Time of Conc, (min) 5.00 Outflow (cfs) 1 23 ft. Overland Flow Design Year Flow 50 Area (acres) 1.31 Cc = 015 , Impervious Area (sq ft) 8393 L= 23 ft. 'C' Factor 0.376 11 = 0.40 '208' Volume Provided 452 S= 0.020 Area ' C 0.493 ic = 1.84 min., by Equation 3-2 of Guidelines Time Time Inc. Intens. Q Devel. Vol.ln Vol.Ouf Storage 4 8`) fi Gutter flow (min) (sec) (iNhr) (cfs) (cu fi) (cu ft) (cu ft) Z1 = 50.0 5.00 300 4.58 2.26 907 300 607 Z 2 = 3.5 n= 0.016 5 300 4.58 2.26 907 300 607 S= 0.020 10 600 3.20 1.58 1106 600 506 15 900 2.45 1.21 1209 900 309 d= 0.179 ft. 20 1200 1.95 0.96 1251 1200 51 ~ 25 1500 1.62 0.80 1278 1500 -222 A R Q Tc Tc total I Qc 30 1800 1.56 0.77 1461 1800 -339 35 2100 128 0.63 1388 2100 -712 0.86 0,09 2.26 3.04 5.00 4.58 2.26 40 2400 1.19 0.58 1460 2400 -940 45 2700 1.08 0.53 1491 2700 -1209 Qpea~ for Case 1= 2.26 cfs 16 50 3000 0.99 0.49 1513 3000 -1487 ; 55 3300 0.92 0.45 1542 3300 -1758 60 3600 0.87 0.43 1586 3600 -2014 CASE 2 ' 65 3900 0.82 0.40 1616 3900 -2284 70 4200 0.80 0.39 1695 4200 -2505 Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.77 0.38 1745 4500 -2155 peak flow =.90(4.58)(Imp Area) = 0.19 cfs 80 4800 0.75 0.37 1811 4800 -2989 85 5100 0.72 0.35 1845 5100 -3255 90 5400 0.71 0.35 1924 5400 -3476 So, ihe Peak flow for the Basin is ihe qreafer of the two flows, p 95 5700 0.69 0,34 1972 5700 -3728 2 26 cfs 100 6000 0.67 0.33 2014 5000 -3986 208' DRAINAGE POND CALCULATIONS Required '208'Storage Volume = Impervious Area x.5 in 112 inlft 350 cu ft '208' Volume Provided 452 cu ft DRYWELL REQUIREMENTS - 50 YEAR DESIGN STORM ; Maximum Storage Required by Bowstring 607 cu ft Total Storage Provided 1056 cu ft r Number and Type of Drywells Required 0 Single 1 Double r~~ ;,rdp r;,rIrIc EtiGIN!7r-RiNG m m m m m m m m m m m m m m m m m m m 50-year STORM BOWSTRING METHOD PROJECT: Shelley Lake 2nd Addition PEAK FL04^J CALCULATION PROJECT Shelley Lake 2nd Addition DETENTION BASIN DESIGN BASIN: E BASIN E DESIGNER: JEM Toc Area 2.23 Acres DATE: 04l21 Imp. Area 7385 SF F'z C = 0.34 Time Incremenl (min) 5 CASE 1 Time of Conc. (min) 6.75 Outflow (cfs) 2 90 ft Overland Flow Design Year Flow 50 Area (acres) 2.23 Ct = 0.15 Impervious Area (sq ft) 7385 L= 90 ft. 'C Factor 0.343 n= 0.40 '208' Volume Provided 402 S= 0.020 Area ` C 0.765 Tc = 4.16 min., by Equation 3-2 of Guidelines << Time Time Inc. Intens. Q Devel. Vol.ln Vol.Out Storage 440 ft Gutter flaw (min) (sec) (inlhr) (cfs) (cu ft) (cu ft) (cu ft) Z1 = 50.0 6.75 405 3.98 3.04 1651 816 841 7? = 3.5 n= 0.016 5 300 4.58 3.50 1408 600 808 S= 0.020 ~ 10 600 3.20 2.45 1806 1200 606 15 900 2.45 1.87 1945 1800 145 d= 0.200 (t. 20 1200 1.95 1.49 1995 2400 -405 25 1500 1.62 1.24 2029 3000 -971 H R Q Tc Tc total I Qc ~ 30 1800 1.56 1.19 2312 3600 -1288 ` 35 2100 1.28 0.98 2191 4200 -2009 ' 07 0.10 3.04 2.59 6.15 3.98 3.04 40 2400 1.19 0.91 2300 4800 -2500 45 2700 1.08 0.83 2344 5400 -3056 Qpeak for Case 1= 3.04 cfs 50 3000 0.99 0.76 2376 6000 -3624 55 3300 0.92 0.70 2419 6600 -4181 60 3600 0.87 0.67 2487 7200 -4713 CASE 2 65 3900 0.82 0.63 2533 7800 -5267 70 4200 0.80 0.61 2654 8400 -5746 Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.77 0.59 2731 9000 -6269 peak flow =.90{4.58}(Imp. Area) = 0.70 cfs 80 4800 0.75 0.57 2833 9600 -6767 85 5100 0.72 0.55 2885 10200 -7315 90 5400 0.71 0.54 3007 10800 -7793 So, the Pe?k flow for fhe Basin is the greater of the two flows, 95 5700 0.69 0.53 3081 11400 -8319 3.04 cfs 100 6000 0.67 0.51 3145 12000 -8855 =;.w 208' DRAINAGE POND CALCULATIONS Required '208'Storage Volume Impervious Area x.5 in ! 12 inlft 308 cu ft '208' Volume Provided 402 cu ft DRYWELL REQUIREMENTS - 50 YEAR DESIGN STORM Maximum Storage Required by Bowstring 841 cu ft Total Storaye Provided 958 cu ft Number and Type of Drywclls Required 0 Single 2 Double ' CURB DROP ANAL YS`IS ' m m m m m m m m m m m m m m m m m m m SHELLEY LAKE 2ND ADDITION CURB INLET CALCULATIONS Curb Inlet Depression = 2 in. Standard Curb Inlet Length = 4 ft. Upstream 10 yr. Gutter Roughness Reciprocal Depth Length Curb Drop Impervious Peak Flow Slope Coeff. Cross slope of Flow Required Pond Station R/L Area c.f.s. S n Z Zln d" QalLa"` Q/(QalLa) Remarks D 12+60 L 8393 1.56 0.0075 0.0160 50 3125 0.18 0.124 12.58 Need 2- 4' and 1- 5' curb inlet * Calculated per Figure 18 of Guidelines Calculated per Figure 16 of Guidelines A 4 foot curb drop with a 6" gutter has a capacity of 4.0 cfs in sump condition. r ~ ~ INLAND PACIFIC ENGINEERING, INC. 707 W. 7th Ave., Suite 200, Spokane, WA 99204 (509) 458-6840 Fax: (509) 458-6844 TO: ; ~ ~~DATE: : . , . ~ ~ ~ . . . „ , ~;:i " ~ ~.P;. PRO~CT-#: ; ; , , . ,'r~ ~ . ~t I;~'~ . ~ i ~,r ~I;~j'(;' ~ - i~' i i ~''~'i ~ ~ ~t ' ~ il' ~ ~~''I,~'I I4.•1 • J'E'~T~~~AME: ATTENTION: , PRO N ~ ' ~ ~ ~ • ~ I~; ^ ~J~~" i ~~~~~';i:~, Description J M-I'Xerox Prints M~ Copy of Letter M~ M~ Original Drawing M~ Contract Documents M~ M~ Work Authorization M~ Report M~ No. Copies ~ Description . ud -#6 v v Purpose M I Information M~ Review & Comments M~ Per Your Request M~ MI Written Approval M~ Signature & Return Remarks , ~ ~v t 1,A aoo-) i~-~- ` • J / i / ~ • ~ ~f - ii~i~ , i.~ , J - Lf~ ` -z Signed: cc: D:\'IRNSMT.PMS 7 ~ INLAND PACIFIC ENGINEERING, 1NC. 707 W. 7th Ave., Suite 200, Spokane, WA 99204 (509) 458-6840 Fax: (509) 458-6844 To: 5pff) ~\-C-!O~ ,'~,i,,,;,,, , , , ' • , ; ~ ~ ~ ' ii'I~ i ,'i~ii~~'~'~i'. I li ~',I~ "'P~~''~ ~ ~ . ; ATTENTION: PROJE~T ~ ~ Description MelXerox Prints M ~ Copy of Letter M~ M~ Original Drawing M~ Contract Documents M~ Work Authorization M~ Report M~ No. Copies Description 1 ( 3> S•.Q-c.c~.~,~~ ~ ~ . 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Signature Date w ~ DRAINAGE REPORT for Shelley Lake - 2nd Addition Spokane County, Washington March,1999 IPE JOB #99029 Prepared by: Inland Pacifrc Engineering Company 707 W 7th Averrue, Suite 200 Spokane, WA 99204 (509)458-6840 This report has been prepared by John McKervey, E.I.T. and the staffof Inland Pacific Engineering Company under the direction of the undersigned professional en$ineer whose seal and signature , appea.r hereon. ~o ~ 71f `5462 ~ dpJYp1, ~ EXPIRE 9 _ 4JAR"~ Todd R. Whipple, P.E. ~ ' ' DRAINAGE REPORT FQR SHELLEY LAKE - 2"d ADDITION INTRODUCTION Shelley Lake ZIId Addition is part of the shelley Lake PUD Plat and is adjacent to that portion of the Shelley La.ke PUD which was included in the original Shelley Lake PUD Plat Drainage Report which ' was completed in June, 1996 and approved. Basin P and Basin A-Temp which were part of the original Shelley Lake PUD drainage report have been incorporated into this report as portions of Basin A and Basin B. Shelley Lake 2' Addition includes 20 lots and adjoins the first phase of Shelley Lake at the southwest corner of the first phase. PURPOSE The purpose of this report is to detemune the extent of storm drainage facilities which will be re~quired to dispose of the increase in stormwater runoff created by the development of Shelley Lake 2 Addition. The storm drainage facilities for this project will be designed to dispose of runoff from ten and fifty year desip storms. This development is within the Aquifer Sensitive Area of Spokane vo~ ) Tounty anc`is subject to `208' requirements. For this project the 10 and 50 year curves from the Spokane, Medical Lake, Reardon, Cheney and Rockford intensity curves were used, as well as the SCS iso-pluviai rainfall curves. Per direction from Spokane County, the SCS curves have been further refined with the NOAA iso-pluvial curves. ANALYSIS METHODOLOGY , The Rational Method, which is recommended for basins less than ten acres in size, will be used to determine the peak discharges and runoffvolumes for a11 basins included in this report. 1 PROJECT DESCRIPTION Shelley Lake 2nd Addition includes 201ots of the approved 262 lots and 459 units in the approved preliminary plat arid FEIS documents. The Shelley Lake subdivision is located in the North'/z ofthe SE 1/4 of the NE 1/4 of Section 24, T. 25 N., R. 44 E., W.M. within Spokane County, Washington. TOPOGRAPHY ' The eneral slo es within this lat v from nearl flat within sever g P p ary y a1 natural saddles to short slopes of up to ZO-percent. Generally, the area covered by this report would be characterized as rolling. For development purposes, the natural sloping was used for design and is maintained as possible throughout the project. Inland Pacific Engineering 1 Shelley Lake 2i°Additiort ' SOII,S ' As can be seen from the accompanying soils map from the Spokane County Soils Sucvey as performed by the SCS, the site consists of two soil types, both within the Class B type. These soils are GgB and GmB and are described as follows. ' Gg.B - Garrison graveUy toam, 5 to 29 percent stopes: Soils within this soil type are somewhat excessively drained soils formed in gravelly giacial outwash material from a variety of igneous rock. Surface runoff is slow and the hazard of erosion is slight. Spokane County Guidelines for Stormwater ManaEement indicate this to be a Soil Group Type B and pre-approI for drywell installation. Hydrologic Soil Classificati'on - B GmB - Garrison very gravelly loam, 0 to S percent slopes: This soil is generally the same as the Garrison gravelly loam, with the only difference being that the surface layer is much more stony and contains very little loam if any. Spokane County Guidelines for Stormwater Manaeement indicate this to be a Soil Group Type B and per-approv for drywell installation. 1 Hydrologic Soil Classification - B DRAINAGE NARRATIVE The offsite drainage which flows into Shelley Lake 2' Addition has been incorporated into the basins included in this drainage report. As Shelley Lake 2' Addition is located within the Aquifer Sensitive A.rea of Spokane County, aU onsite drainage will be collected and treated using the `208' runoff ' method as described in the Spokane County Guidelines for Stormwater Mana.gement. To facilitate this analysis Shelley Lake 2nd Addition was divide into 3 basins (A, B and D). The following Table 1 lists the basin details. Table 1- Pond and Basin Sum»urry ' - " . - . - - ; . _ . Pond and Basin Summary _ Pxondi-Basin. ,Y, ~otal '~Total Imp ea Ar , - ervious Weighted ~*,208' Impervious: SFY:(AC) Area SF (AG) `C' . -Area " SF; - A A 942090 (2.16) 312624 (0.73) 0.402 17,625 ' B B 221,286 (5.08) 19,689 (0.45) 0.217 14,256 C C 62, 726 (1.44) 62)726 (1.44) 0.900 62,1726 D D 57,063 (1.31) 172206 (0.40) 0.376 8,393 E E 97,139 (2.23) 25,003 (0.57) 0.343 71385 * Total Impervious Area includes paved roadway area, 1600 sf per roof and 600 s.f per dciveway. `208' Impervious Area includes onty the paved roadway area Inland Pacific Engineerirtg 2 Shelley Lake 2"dAddition ' "208 " CQlCUIQtIOI=S ' Within each basin, the street areas from back of curb to back of curb were calculated to determine the required `208' storage. As shown on the `208' calculation worksheets inch,ided, the `248' stora.ge volumes provided are adequate to perforrn the ` 208' treatment for the first half inch of rainfall. In addition to `208' treatment, the enclosed worksheets also show the calculations for the drywell requirements. The `208' storage and drywell requirements for each basin are summarized on the following Table 2. ' Table 2-`208' Treatment and Drywell Requirement Summary , W;~•,~ yf"•-t~'' P~~"' ' ~ . . , , ~ `208 sTreatm`ent an,it D {rywell Summary :tr:•, _ :~t~,~;5 , . ' Pond Basin `208' VoluQi~ e~ `208-' 'A rea Required 1208' _ ''µ~~;r ~ Area , D,r-.y.:weU~ Re ~ _ c~uir e d.(CF) ~i~~:~(SF) Provided Re~ A A 734 131096 1,120 1-Type B B B 594 887 211192 1-Type B C C 2614 32901 51476 1-Type B D D 350 452 675 1-Type B , E E 308 402 600 2-Type B, * Based on a`208' storage depth of 8 inches. Side slope votucne is not inclucled. Total Stormwater Storage Calculations In addition to the `208' storage requirements, the total stormwater storage for the 10-year design , storm was also considered. Each of the ponds in Shelley Lake 2"d Addition will have the ca.pacitY to contain the required volume for the 10-year design storm. In addition, the 50-year design storm was also exa.mined to determine the amount of overIlow expected. This information is summariz,ed in the ' following Table 3. Inlartd Pacific Engirreering 3 Shelley Lake 2~Addition , Table 3- IO-year and Sa-year Stormwater Storage Volume Summary ~ 10-year and 50 --ye tora ar;S,,. MeNolummary=-by Bowstring gat .`t :1~x; . -~,~;r.r'+ , _ , . < : i;~k.4R4°~' , • ~ ~aF t ti.~. ~~'`z, : . - - > • :T, ;Pond ~x~B ~ asi ~ - ~.~~c, ` ~7""r : , ' , , • . {s { i;; ~ n• 10-year, 50-year .50-year► • ,7~~1 A~Y'l,yY ~W, b •ry_.1',' - ~n''i - ~ •aT,r~~~ .~~~:u;~`~;;-. ~ Volume: Volume . ~FVoluine ~ l~t ~~1s` T~: . : ~ ' ! ~r`/ L IY~~lYr1X~'.' eq°ired - Provx 1®r~ R . rded A rr'' . ~+2• ~ r ~ ~ ~ y~ ~ (CF) , A A 953 J 1,344 11564 12642 +78 B B 173981 23630 2)208 2,954 +746 C C 3,4611 62571 5,496f? 7~ + ,323 1,827 D D 339 y 810 607 J 1,056 +449 E E 369 f 720 841 958 +117 * SO-year Vohune Provided includes side slope volume As ca.n be seen in Table 3 all of the ponds will contain the 10-year and 50-year design storms. Curb Drop/Inlet Anadysis The inlet for Pond D is on grade and therefore a curb drop analysis was performed for this pond. The analysis shows that the pond requires 12.58 feet of curb drop opening, therefore 2- 4' inlets and 1- 5' inlet will be used to capture the stormwater for this pond. The inlets for the remaining ponds are in sump condition. , Inland Pacific Engineering 4 Shelley Lake 2"dAddition 1 1 ~ ~ APPENDIx r r f I 1l l~ P~ -•rys ~ . ; ~ P~E~ A ' - /'eCLK'=~. ..~/'``'%.1 ••~~r. . - , 1~.i~~•;' NOT TO SCALE , / ~ ~ INLAND PACIFIc SHELLEY LAKE 2ND ADDITION I ENGINEERING 707 west 7tn • suite ~oo (sas) 458-6840 SOlLS iv1AP oA-1L: .~/o~~,/~ ~ \ 5pokane, WA 99204 FAX (509) 458-6344J ~ - ] . ~ l FACT'~RS E~ ~ ' Weighted Runoff Coefficient Calculation ' Project: Shelley Lake 2nd Addition Basin: A . IPE Job 99029 Total Area (acres: 2.16~ Designei J. McKervey ' I mP. Area (acres) 0.726 Date: 03/25/99 Grass Area {acre: 1.43400f Imp. Area "C": 0.9000 Grass Area "C": 0.15 ' (Imp. Area)(Imp. "C")= 0.6534 ' (Grass Area)(Grass "C")= 0.2151 2.1600 0.8685 Weighted "C"= 0.8685 0.4021 2.1600 ' ' ' ' Weighted Runoff Coefficient Calculation Project: Shelley Lake 2nd Addition Basira: B ~ IPE Job 99029 Total Area (acres. 5.08~ Designei J. McKervey Imp. Area (acres) 0.452 Date: 03/15/99 Grass Area (acre: 4.6280 Imp. Area "C": 0.9000 Grass Area "C": 0.15 (Imp. Area)(Imp. "C")= 0.4068 (Grass Area)(Grass "C")= 0.6942 5.0800 1.1010 Weighted "C"= 1.1010 0.2167 5.0800 ' ' ' 0 ' Weighted Runoff Coefficient Calculation ' Project: Shelley Lake 2nd Addition Basin: C ~ IPE Job 99029 Total Area (acres): 9.21~ Designer: J. McKervey ' I mp. Area (acres): 1.44 Date: 03/25/99 Grass Area (acres): 7.7700 I mp. Area "C": 0.9000 G rass Area "C": 0.15 (Imp. Area)(Imp. "C")= 1.2960 , (Grass Area)(Grass "C")= - 1.1655 . 9.2100 2.4615 Weighted "C"= 2.4615 0.267264 9.2100 ' ' ' Weighted Runoff Coefficient Calculation ' Project: Shelley Lake 2nd Addition Basin: D ~ IPE Job 99029 » Total Area (acres. 1.31 Designei J. McKervey ' Imp. Area (acres) 0.395V Date: 03/25/99 Grass Area (acre: 0.9150 Imp. Area "C": 0.9000 Grass Area "C": 0.15 (Imp. Area)(Imp. "C")= 0.3555 (Grass Area)(Grass "C")= 0.1373 - - 1.3100 0.4928 Weighted "C"= 0.4928 0.3761 . 1.3100 , ' Weighted Runoff Coefficient Calculation ' Project: Shelley Lake 2nd Addition Basin: E . IPE Job 99029 Total Area (acres: 2.23 1~ Designei J. McKervey I mp. Area (acres) 0.574 Date: 03/25/99 Grass Area (acre; 1.6560 Imp. Area "C": 0.9000 Grass Area "C": 0.15 (Imp. Area)(Imp. "C")= 0.5166 (Grass Area)(Grass "C")= 0.2484 2.2300 0.7650 Weighted "C"= 0.7650 0.343 2.2300 r ~ ~ B n yYSTRING C'ALC ULA TI4.11TS` ~ ~ . ~ ~ ~ ~ ~ r ~ ~ ~ mmmmm mmm mmm BOWSTRING METHOD PROJECT Sheney Lake 2nd Addition PEAK FLOW CALCULATION PROJECT:Shelley Lake 2nd Addition DETENTION BASIN DESIGN BASIN: A BASIN: A 10-Year Design Storm DESIGNEf J. McKervey . Tot. Area 2,16 Acres DATE: 04106199 Imp. Area 17625 SF C = 0.40 Time Increment (min) 5 CASE 1 Time of Conc. (min) 9.24 Outflow (cfs) 1 76 ft. Overiand Flow Design Year Flow 10 Area (acres) $0Ap'j*.a !J Ct = 0.15 Impervious Area (sq ft) 176 L= 76 ft. 'C' Factor . 2 A -S ip'' 1ps n= 0.40 '208' Volume Provided 750 '0#'j ~ S= 0.030 Area " C 0.868 Tc = 3.33 min., by Equation 3•2 of Guidelines Time Time Inc. ►ntens. Q Devei. Voi.ln Vol.Out Storage 700 ft. Gutter flow (min) (sec) (inlhr) (cfs) (cu ft) (cu ft) (cu ft) Z1 = 50.0 For Z2 9,24 554 2.34 2.03 1507 554 953 Z2 = 3.5 Type B =1.0 n= 0.016 Rolled = 3,5 5 3Q0 3.18 2.76 1110 300 810 S= 0.010 10 600 2.24 1.95 1534 60d 934 15 900 1.71 1.54 1673 900 773 d= 0,196 ft. 20 1200 1.45 1.26 1748 1200 548 25 1500 1,21 1,05 1774 1500 274 A R Q Tc Tc total I Qc 30 1800 1,Q4 0.90 1796 1800 -0 35 2100 0,91 0.79 1808 2100 -292 1.03 0.10 2.03 5.91 9.24 2,34 2.03 40 2400 0,82 0.71 1843 2400 -557 ' 45 2700 0.74 0.64 1858 2700 -844 Qpeak for Case 1= 2.03 cfs 50 3Q00 0,68 0.59 1883 3000 -1117 55 3300 0.64 0.56 1939 3300 -1361 60 3600 0.61 0.53 2007 3600 -1593 CASE 2 65 3900 Q.60 0.52 2130 3900 -1770 70 4200 0,58 0.50 2210 4200 -1990 Case 2 assumes a Time of Concentration less than 5 minates so ftt the 75 4500 0.56 0,49 2280 4500 -2220 peak flow =.90(3.18)(Imp. Area) = 1.16 cfs 80 4800 0.53 0.46 2296 4800 -2504 85 5100 0.52 0.45 2388 5100 -2712 90 5400 0.50 0.43 2426 5400 -2974 So, the Peak flow for the Basin is the greater of the two flows, 95 5700 0.49 0.43 2505 5700 -3195 2.03 cfs 100 6000 0,48 0.42 2579 6000 -3421 _ 208' DRAINAGE POND CALCULATIONS Required'208' Storage Volume , = Impervious Area x.5 in / 12 inlft 734 cu ft 208' Storage Volume Provided 750 cu ft DRYWELL REQUIREMENTS -10 YEAR DESIGN STO Maximum Storage Required by Bowstring 953 cu ft Total Storage Provided 1007 cu ft Number and Type of Dryweus Required 0 Single 1 Double ~ ~ i ~ r ~ ~ ~ r ~ ~ ~ ~ ~ ~ ~ s ~ BOWSTRING METHOD PROJECT: Shelley Lake 2nd Addition PEAK FLOW CALCULATION PROJECT Shelley Lake 2nd Addition DETENTION BASIN DESIGN BASIN: B BASIN: B 10-Year Design Storm DESIGNER: J. McKervey Tot. Area 5.08 Acres DATE: 03125199 Imp. Area 14256 SF C = 0.22 Time Increment (min) 5 CASE 1 Time of Conc. (min) 9.70 Outflow (cfs) 1 680 ft. Overland Flow Design Year Flow 10 Area (acres) 5.08 Ct = 0.15 Impervious Area (sq ft) 14256 ~ L= 680 ft. 'C' Factor 0.22 n= 0.40 '208' Volume Provided 1469 S= 0.100 Area " C 1.118 Tc = 8.65 min., by Equation 3-2 of Guidelines Time Time Inc. Intens. Q Devel. Vol.in Vol.Out Storage 200 ft. Gutter flow (min) (sec) (inlhr) (cfs) (cu ft) (cu ft) (cu ft) Z1 = 50.0 For Z2 9,70 582 2.27 2,54 1980 582 1398 Z2 = 3.5 Type B =1.0 ' n= 0.016 Rolled = 3.5 5 300 3.18 3.55 1429 300 1129 S= 0.030 10 600 2,24 2.54 1998 600 ' 1398 15 900 1.77 1.98 2172 900 1272 d= 0.174 ft. 20 1200 1.45 1.62 2265 1200 1065 , 25 1500 1.21 1.35 2296 1500 796 A R Q Tc Tc total I Qc 30 1800 1.04 1.16 2322 1800 522 35 2100 0.91 1.02 2337 2100 237 0.81 0.09 2.54 1.06 9.70 2.27 2.54 40 2400 0.82 0.92 2381 2400 -19 45 2700 0.74 0,83 2397 2700 -303 Qpeak for Case 1= 2.54 cfs 50 3000 0,68 0.76 2430 3000 -570 55 3300 0,64 0.72 2502 3300 -798 60 3600 0.61 0.68 2589 3600 -1011 CASE 2 65 3900 0.60 0.67 2748 3900 -1152 70 4200 0.58 0.65 2851 4200 -1349 Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.56 0.63 2940 4500 -1560 peak flow =.90(3.18)(Imp. Area) = 0.94 cfs 80 4800 0.53 0.59 2960 4800 -1840 85 5100 0.52 0.58 3079 5100 -2021 90 5400 0.50 0.56 3128 5400 -2272 So, the Peak flow for the Basin is the greater of the two flows, 95 5700 0.49 0.55 3230 5700 -2470 2.54 cfs 100 6000 0,48 0.54 3325 6000 -2675 208' DRAINAGE POND CALCULATIONS Required'208' Storage Volume = Imperoious Area x,5 in ! 12 inlft 594 cu ft 208' Storage Volume Provided 1469 cu ft DRYWELL REQUIREMENTS -14 YEAR DESIGN STORI Maximum Storage Required by Bowstring 1398 cu ft ` Total Storage Provided 1973 cu ft Number and Type of Drywells Required 0 Single 1 Double BOWSTRING METHOD PROJECT: Shelley Lake 2nd Addition PEAK FLOW CALCULATION PROJECT Shelley Lake 2nd Addition DETENTION BASIN DESIGN BASIN: C BASIN: C 10-Year Design Storm DESIGNER: J. McKervey Tot, Area 9,21 Acres DATE: 03125199 Imp. Area 62726 SF C = 0.27 Time Increment (min) 5 CASE 1 Time of Conc. (min) 5.00 Outflow (cfs) 1 300 ft. Overland Flow Design Year Flow 10 Area (acres) 9.21 ~ Ct = 0.15 Impervious Area (sq ft) 62726 L= 300 ft. 'C' Factor 0.267 n= 0.02 '208' Volume Provided 3669 S= 0.020 Area' C 2.459 ` Tc = 1.24 min., by Equation 3-2 of Guidelines Time Time Inc. Intens. Q Devel. Vol.ln Vol.Out Storage 1050 ft. Gutter flow (min) (sec) (inlhr) (cfs) (cu ft) (cu ft) (cu ft) Z1= 25.0 For Z2 5.00 300 3.18 7.82 3144 300 2844 Z2 = 1 Type B =1.0 - - n= 0.016 Rolled = 3.5 5 300 3.18 7.82 3144 300 2844 S= 0.045 10 600 2.24 5.51 3867 600' 3267 15 900 1.77 4.35 4361 900 3461 d= 0.322 ft. 20 1200 1,45 3.57 4642 1200 3442 25 1500 1,21 2.98 4767 1500 3267 A R Q Tc Tc total I Qc 30 1800 1.04 2.56 4864 1800 3064 35 2100 0.91 2.24 4928 2100 2828 1.35 0.16 7.82 3.02 5,00 3.18 7.82 40 2400 0.82 2.02 5045 2400 2645 45 2700 0.74 1.82 5099 2700 2399 Qpeak for Case 1= 7.82 cfs 50 3000 0.68 1.67 5187 3000 2187 55 3300 0.64 1.57 5354 3300 2054 60 3600 0.61 1.50 5553 3600 1953 ' CASE 2 65 3900 0,60 1.48 5905 3900 2005 70 4200 0.58 1.43 6136 4200 1936 Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.56 1.38 6337 4500 1837 peak flow =.90(3,18)(Imp. Area) = 4.12 cfs 80 4800 0.53 1.30 6389 4800 1589 , 85 5100 0.52 1.28 6652 5100 1552 90 5400 0,50 1.23 6765 5400 1365 , So, the Peak flow for the Basin is the greater of the two flows, 95 5700 0.49 1.20 6991 5700 1291 7.82 cfs 100 6000 0.48 1.18 7203 6000 1203 208' DRAINAGE POND CALCULATIONS Required'208' Storage Volume , = Imperoious Area x.5 in 112 iNft 2614 cu ft 208' Storage Volume Provided 3669 cu ft ORYWELL REQUIREMENTS -10 YEAR DESIGN STORM Maximum Storage Required by Bowstring 3461 cu ft Total Storage Provided 4928 cu ft Number and Type of Drywells Required 0 Single ' 1 Double BOWSTRING METHOD PROJECT: Shelley Lake 2nd Addition PEAK FLOW CALCULATION PROJECT Shelley Lake 2nd Addition DETENTION BASIN DESIGN BASIN: D BASIN: D ' 10-Year Design Storm DESIGNER: J. McKervey Tot, Area 1.31 Acres DATE: 03125J99 Imp. Area 8393 SF C = 0.38 Time Increment (min) 5 ' CASE 1 Time of Conc. (min) 5.17 Outflow (cfs) 1 23 ft. Overland Flow Design Year Fiow 10 Area (acres) 1.31 Ct = 0.15 Impervious Area (sq ft) 8393,0e L= 23 ft. 'C' Factor 0.38 n= 0.40 '208' Volume Provided 452 S= 0,020 Area * C 0.498 Tc = 1.84 min,, by Equation 3-2 of Guidelines Time Time Inc. Intens. Q Devel. Vol.ln Vol.Out Storage 480 ft. Gutter flow (min) (sec) (inlhr) (cfs) (cu ft) (cu ft) (cu ft) Z1= 50.0 For Z2 5.17 310 3.14 1.56 649 310 339 Z2= 3.5 TypeB=1.4 n= 0.016 Rolled = 3.5 5 300 3.18 1.58 636 300 336 S= 0.020 10 600 2.24 1.12 787 600 187 15 900 1.77 0.88 886 900 -14 d= 0.156 ft. 20 1200 1.45 0.72 942 1200 -258 25 1500 1.21 0.60 967 1500 -533 A R Q Tc Tc total I Qc 30 1800 1.04 0.52 986 1800 -814 35 2100 0.91 0.45 999 2100 -1101 0.65 0.08 1.56 3.33 5.17 3,14 1.56 40 2400 0.82 0.41 1023 2400 -1377 45 2700 0.74 0.37 1033 2700 -1667 Qpeak for Case 1= 1.56 cfs 50 3000 0.68 0.34 1051 3000 -1949 55 3300 0.64 0.32 1085 3300 -2215 60 3600 0.61 0.30 1125 3600 -2475 CASE 2 65 3900 0.60 0.30 1196 3900 -2704 70 4200 0.58 0.29 1243 4200 -2957 Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.56 0.28 1284 4500 -3216 peak flow =,90(3.18)(Imp. Area) = 0.55 cfs 80 4800 0.53 0.26 1294 4800 -3506 85 5100 0.52 0.26 1347 5100 -3753 90 5400 0.50 0.25 1370 5400 -4030 So, the Peak flow for the Basin is the greater of the firuo flows, 95 5700 0.49 0.24 1416 5700 -4284 1.56 cfs 100 6000 0.48 0.24 1459 6000 -4541 208' DRAINAGE POND CALCULATIONS Required '208' Storage Volume Imperoious Area x.5 in I 12 inlft 350 cu ft 208' Storage Volume Provided 452 cu ft DRYWELL REQUIREMENTS -10 YEAR DESIGN STORI Maximum Storage Required by Bowstring 339 cu ft Total Storage Provided 452 cu ft Number and Type of Drywells Required 0 Single ' 1 Double ~r ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ r ~ ~ ~ BOWSTRING METHOD PROJECT: Sheliey Lake 2nd Addition PEAK FLOW CALCULATION PROJECT Shelley Lake 2nd Addition DETENTION BASIN DESIGN BASIN: E BASIN: E 10-Year Design Storm DESIGNER: J. McKervey Tot. Area 2.23 Acres DATE: 03125199 Imp. Area 7385 SF C = 0.34 Time Increment (min) 5 CASE 1 Time of Conc. (min) 7.03 Outflow (cfs) 2 90 ft. Overland Flow Design Year Flow 10 Area (acres) 2.23,~/ Ct = 0.15 Impervious Area (sq ft) 73$5~ L= 90 ft. 'C' Factor 0.34 n= 0,40 '208' Volume Provided 402 S= 0.020 Area " C 0.758 Tc = 4.16 min., by Equation 3-2 of Guidelines Time Time Inc. Intens. Q Devel. Vol.ln Vol.Out Storage 440 ft. Gutter flow (min) (sec) (in/hr) (cfs) (cu ft) (cu ft) (cu ft) Z1 = 50.0 For Z2 7.03 422 2.68 2.03 1146 843 303 Z2= 3.5 TypeB=1.0 n= 0.016 Rolled = 3.5 5 300 3.18 2.41 969 600 369 S= 0.020 10 600 2.24 1.70 1263 1200 63 15 900 1.77 1.34 1400 1800 -400 d= 0.172 ft. 20 1200 1.45 1.10 1477 2400 -923 25 1500 1.21 0.92 1508 3000 -1492 A R Q Tc Tc total I Qc 30 1800 1.04 0.79 1532 3600 -2068 35 2100 0.91 0.69 1548 4200 -2652 0.79 0.09 2.03 2.86 7.03 2.68 2.03 40 2400 0.82 0.62 1581 4800 -3219 45 2700 0.74 0.56 1595 5400 -3805 Qpeak for Case 1= 2.03 cfs 50 3000 0.68 0.52 1621 6000 -4379 55 3300 0.64 0.49 1671 6600 -4929 60 3600 0.61 0,46 1731 7200 -5469 CASE 2 65 3900 0.60 0.45 1839 7800 -5961 70 4200 0.58 0.44 1910 8400 -6490 Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.56 0.42 1972 9000 -7028 peak flow =.90(3.18)(Imp. Area) = 0.49 cfs , 80 4800 0.53 0.40 1986 9600 -7614 85 5100 0.52 0.39 2067 10200 -8133 ' 90 5400 0.50 0.38 2101 10800 -8699 So, the Peak flow for the Basin is the greater of the two flows, 95 5700 0.49 0.37 2171 11400 -9229 2.03 cfs 100 6000 0.48 0.36 2236 12000 -9764 208' DRAINAGE POND CALCULATIONS Required'208' Storage Volume , = Impervious Area x.5 in I 12 iNft 308 cu ft 208' Storage Volume Provided 402 cu ft DRYWELL REQUIREMENTS -10 YEAR DESIGN STORI Maximum Storage Required by Bowstring 369 cu ft Total Storage Provided 540 cu ft Number and Type of Dryvuells Required 0 Single 2 Double ~ ~ ~ ~ ~ s ~ ~r ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 50-year STORM BOWSTRING METHOD PROJECT:Shelley Lake 2nd Additon PEAK FLOW CALCULATION PROJECT:Shelley Lake 2nd Addfion DETENTION BASIN DESIGN BASIN: A BAS1N A DESIGNEFJEM Tot. Area 2.16 Acres DATE: 04106 Imp. Area 17625 SF C = 0.40 Time Increment (min) 5 CASE 1 Time of Cortc. (min) 8.76 Outflow (cfs) 1 76 ft. Overland Flow Design Year Flow 50 ' Area (acxes) 2.16 Ct = 0.15 Impervious Area (sq ft) 17625 L= 76 ft. 'C' Factor 0,402 n= 0.40 '20$' Volume Provided 750 S= 0.030 Area * C 0.868 Tc = 3,33 min., by Equatlon 3-2 of Guidelines , Time Time Inc. Intens. Q Devel, Vol,ln Vol.Out Storage 700 R Gutter flow (min) (sec) (in/hr) (cfs) (cu ft) (cu ft) (cu ft ) - Z1 = 50,0 8.76 525 3.28 2.85 2008 525 1482 Z2 = 3.5 . n= 0.016 5 300 4.58 3,98 1599 300 1299 S= 0.010 10 600 3.20 2.78 2164 600 * 1564 15 900 2.45 2,13 2295 900 1335 d= 0.223 ft. 20 1200 1.85 1,69 2334 1200 1134 25 1500 1.62 1.41 2361 1500 861 A R Q Tc Tc total I Qc 30 1800 1.56 1.35 2660 1800 880 35 2100 1.28 1.11 2533 2100 433 1.33 0.11 2.85 5.42 8.76 3.28 2.85 40 2400 1.19 1,03 2853 2400 253 45 2700 1.08 0.94 2700 2700 -0 Qpeak for Case 1= 2.85 cfs 50 3000 0.99 0.86 2732 3000 -268 55 3300 0.92 0.80 2779 3300 -521 60 3600 0.87 0.76 2855 3600 -745 CASE 2 65 3900 0.82 0.71 2904 3900 -996 70 4200 0,80 0.69 3042 4200 -1158 Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.77 0.67 3128 4500 -1372 peak flow =,90(4.58)(Imp. Area) = 1.67 cfs BO 4800 0.75 0.65 3242 4800 -1558 85 5100 0.72 0.63 3300 5100 -1800 94 5400 0,71 0.62 3439 5400 -1961 So, the Peak flow for tfie Basin is the greater of the two flows, 95 5700 0,69 0.60 3522 5700 -2178 2.85 cfs 100 6000 0.67 0.58 3595 6000 -2405 208' DRAINAGE POND CALCULATIONS Required'208' Storage Volume = Imperviaus Area x.5 in ! 12 in/ft 734 cu ft ' '208' Volume Provided 750 cu ft DRYWELL REQUIREMENTS - 50 YEAR DESIGN STORM Maximum Storage Required by Bowstring 1564 cu ft Total Storage Provided 1007 cu ft ~ Number and Type of Drywells Required 0 Single 1 Double ' INLAND PACIFlC ENOINEERING ' m m m m m m m m m m m m m m m m m m m 50-year STORM BOWSTRING METHOD PROJECT Shelley Lake 2nd Addition PEAK FLOW CALCULATION PROJECT Shelley Lake 2nd AddiGon DETENTION BASIN DESIGN BASIN; B BASIN B DESIGNEI JEM Tot, Area 5.08 Acres DATE: 03125 Imp, Area 14256 SF C = 0.22 Time Increment (min) 5 CASE 1 Time of Conc. (min) 9.61 Outflow (cfs) 1 680 ft. Overland Flow Design Year Flow 50 Area (acres) 5.08 Ct = 0.15 ImpeNious Area (sq ft) 14255.67 L= 680 ft. 'C' Factor 0.217 n= 0.40 '208' Volume Provided 1469 S= 0,100 Area' C 1.102 Tc = 8.65 min., by Equation 3-2 of Guidelines . Time Time Inc. Intens. Q Devel. Vol.ln Vol.Out Storage 200 ft. Gutter flow (min) (sec) (inlhr) (cfs) (cu ft) (cu ft) (cu ft) ~ Z1 = 50.0 9.61 577 3,07 3.38 2613 577 2036 Z2 = 3.5 n= 0.016 5 300 4,58 5.05 2030 300 1730 S= 0.030 10 600 3.20 3.53 2808 600 2208 15 900 2.45 2.70 2960 900 2060 ' d= 0.198 ft. 20 1200 1.95 2.15 3001 1200 1801 25 1500 1,62 1.79 3029 1500 1529 A R Q Tc Tc total I Qc 30 1800 1.56 1.72 3433 1800 1633 35 2100 1.28 1.41 3240 2100 1140 1.05 0.10 3,62 0.97 9.61 3.07 3.38 40 2400 1.19 1.31 3391 2400 991 45 2700 1.08 1.19 3448 2700 748 Qpeak for Case 1= 3.38 cfs 50 3000 0.99 1.09 3488 3000 488 55 3300 0.92 1.01 3546 3300 246 60 3600 0.87 0.96 3641 3600 41 CASE 2 65 3900 0.82 0.90 3703 3900 -197 70 4200 0.80 0.88 3877 4200 -323 Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.77 0.85 3986 4500 -514 peak flow =.90(4,58)(Imp. Area) = 1.35 cfs 80 4800 0.75 0.83 4131 4800 -669 85 5100 0.72 0.79 4204 5100 -896 90 5400 0.71 0.78 4380 5400 -1020 So, the Peak flow for the Basin is the greater of the two flows, 95 5700 0.69 0.76 4485 5700 -1215 3.38 cfs 100 6000 0.67 0.74 4576 6000 •1424 208' DRAINAGE POND CALCULATIONS Required'208' Storage Voiume = Impervious Area x.5 in 112 in/ft 594 cu ft , '208' Volume Provided 1469 cu ft DRYWELL REQUIREMENTS - 50 YEAR DESIGN STORM Maximum Storage Required by Bowstring 2208 cu ft Total Storage Provided 1973 cu ft Number and Type of Orywelis Required 0 Single 1 Double INLAND PACIFIC ENGINEERING m m m m m m m m m m m m m m m m m m m 50-year STORM BOWSTRING METHOD PROJECT: Shelley Lake 2nd Addition PEAK FLOW CALCULATION PROJECT Shelley Lake 2nd Addition DETENTION BASIN DESIGN BASIN: C BASIN C DESIGNER: JEM Tot. Area 1.44 Acres DATE: 03125 Imp. Area 62726 SF C = 0.90 Time Increment (min) 5 CASE 1 Time of Conc. (min) 5.00 Outflow (cfs) 0.3 40 ft. Overland Flow Design Year Flow 50 Area (aaes) 1.44 Ct = 0.15 Impervious Area (sq ft) 62726 ` L= 40 ft. 'C' Factor 0.9 n= 0.02 '208' Volume Provided 3669 S= 0.020 Area " C 1.296 Tc = 0.37 min., by Equation 3-2 of Guidelines Time Time Inc. Intens. Q Oevel, Vol.in Vol.Out Storage 1010 ft. Gutter flow (min) (sec) (iNhr) (cfs) (cu ft) (cu ft) (cu ft) Z1= 25.0 5.00 300 4.58 5.94 2386 90 2296 Z2 = 1 n= 0.016 5 300 4.58 5.94 2386 90 2296 S= 0.045 10 600 3.20 4.15 2911 180 ~ 2731 15 900 2.45 3,18 3182 270 2912 d= 0.291 ft, 20 1200 1.95 2.53 3290 360 2930 25 1500 1.62 2.10 • 3363 450 2913 A R Q Tc Tc total I Qc 30 1800 1.56 2,02 3845 540 3305 35 2100 . 1.28 1.66 3653 630 3023 1.10 0.14 5.94 3.12 5.00 4.58 5.94 40 2400 ' 1.19 1.54 3542 720 3122 45 2700 1.08 1.40 3922 810 3112 Qpeak for Case 1= 5.94 cfs 50 3000 0.99 1.28 3980 900 3080 55 3300 0.92 1,19 4056 990 3066 60 3600 0.87 1,13 4174 1080 3094 CASE 2 65 3900 0.82 1.06 4253 1170 3083 70 4200 0.80 1.04 4460 1260 3200 Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.77 1,00 4592 1350 3242 peak flow =.90(4.58)(Imp. Area) = 5,94 cfs 80 4800 0.75 0.97 4765 1440 3325 85 5100 0.72 0.93 4854 1530 3324 , 90 5400 0.71 0.92 5063 1620 3443 So, the Peak flow for the Basin is the greater of the two flows, 95 5700 0.69 0.89 5188 1710 3478 5.94 cfs 100 6000 0.67 0.87 5298 1800 3498 208' DRAINAGE POND CALCULATIONS Required'208' Storage Volume = Impervious Area x.5 in 112 iNft 2614 cu ft '208' Volume Provided 3669 cu ft DRYWELL REQUIREMENTS - 50 YEAR DESIGN STORM Maximum Storage Required by BowsUing 3325 cu ft Total Storage Provided 4928 cu ft Number and Type of Drywells Required 1 Single 0 Doubie INLAND PACIFIC ENGINEERING m m m m m m m m m m m m m m m m m m m 54-year STORM BOWSTRING METHOD PROJECT; Shelley Lake 2nd Addition ` PEAK FLOW CALCULATION PROJECT Shelley Lake 2nd Addition DETENTION BASIN DESIGN BASIN: D BASIN D DESIGNER: JEM Tot. Area 1.31 Acres DATE: 03125 Imp. Area 8393 SF C = 0.38 Time Increment (min) 5 CASE 1 Time of Conc. (min) 5,00 ouKlow (cfs) 1 23 ft, Overland Flow Design Year Flow 50 Area (acres) 1.31 Ct = 0.15 Impervious Area (sq ft) 8393 L= 23 ft. 'C' Factor 0.376 n= 0.40 '208' Volume Provided 452 S= 0.020 Area' C 0.493 Tc = 1.84 min., by Equation 3-2 of Guidelines Time Time Inc. Intens. Q Devel. Vol,ln Vol,Out Storage 480 ft. Gutter flow (min) (sec) (inlhr) (cfs) (cu ft) (cu ft) (cu ft) Z1 = 54.0 5.00 300 4.58 2.26 907 300 607 Z2 = 3.5 n= 0.016 5 300 4.58 2.26 907 300 607 S= 0.020 10 600 3.20 1.58 1106 600 506 15 900 2.45 1.21 1209 900 ' 309 d= 0.179 ft, 20 1200 1.95 0.96 1251 1200 51 25 1500 1.62 0.80 1278 1500 -222 A R Q Tc Tc total I Qc 30 1800 1,56 0.77 1461 1800 •339 35 2100 1.28 0.63 1388 2100 -712 0.86 0.09 2.26 3.04 5.00 4.58 2.26 40 2400 1.19 0.58 1460 2400 -940 45 2700 1.08 0.53 1491 2700 -1209 Qpeak for Case 1= 2.26 cfs 50 3000 0.99 0.49 1513 3000 -1487 55 3300 0.92 0.45 1542 3300 -1758 60 3600 0,87 0.43 1586 3600 -2014 CASE 2 65 3900 0.82 0.40 1616 3900 -2284 70 4200 0.80 0.39 1695 4200 -2505 Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.77 0.38 1745 4500 -2755 peak flow =.90(4.58)(Imp, Area) = 0.79 cfs 80 4800 0.75 0.37 1811 4800 -2989 85 5100 0.72 0.35 1845 5100 -3255 90 5400 0.71 0.35 1924 5400 -3476 So, the Peak flow for the Basin is the greater of the two 8ows, 95 5700 ,0.69 0.34 1972 5700 -3728 2.26 cfs 100 6000 0.67 0.33 2014 6000 -3986 208' DRAINAGE POND CALCULATIONS Required'2Q8' Storage Volume ' = Imperoious Area x.5 in I 12 iNft 350 cu ft . '208' Volume Provided 452 cu ft DRYWELL REQUIREMENTS - 50 YEAR DESIGN STORM Maximum Storage Required by Bowstring 607 cu ft Total Storage Provided 608 cu ft Number and Type of Drywells Required 0 Single 1 Double INLAND PAGFIC ENGINEERING m m m m m m m m m m m m m m m m m m m 50-year STORM BOWSTRING METHOD PROJECT: Shelley Lake 2nd Addition PEAK FLOW CALCULATION PROJECT Shelley Lake 2nd Addition DETENTION BASIN DESIGN BASIN: E BASIN E DESIGNER: JEM Tot, Area 2,23 Aues DATE: 03125 Imp. Area 7385 SF C = 0.34 Time Increment (min) 5 CASE 1 Time of Conc. (min) 6.75 Outflow (cfs) 2 90 ft. Overland Flow Design Year Flow 50 Area (acres) - 2.23 Ct = 0.15 Impervious Area (sq ft) 7385 L= 90 ft. 'C' Factor 0.343 n= 0.40 '208' Volume Provided 402 S= 0.020 Area' C 0,765 Tc = 4.16 min., by Equation 3-2 of Guidelines Time Time Inc. Intens. Q Devel. Vol.ln Vol.Out Storage 440 ft, Gutter flow (min) (sec) (inlhr) (cfs) (cu ft) (cu ft) (cu ft) Z1= 50.0 6.75 405 3.98 3.04 1651 810 841 Z2 = 3.5 n= 0.016 ' 5 300 4,58 3.50 1408 600 808 5= 0.020 .10 600 3.20 2,45 1806 1200 606 15 900 2.45 1.87 1945 1800 ' 145 d= 0.200 ft. 20 1200 1.95 1.49 1995 2400 -405 25 1500 1.62 1.24 2029 3000 -971 A R Q Tc Tc total I Qc 30 1800 1.56 1,19 2312 3600 -1288 35 2100 128 0.98 2191 4200 -2009 1.07 0.10 3.04 2.59 6.75 3.98 3.04 40 2400 1.19 0.91 2300 4800 -2500 45 2700 1.08 0,83 2344 5400 -3056 Qpeak for Case 1= 3.04 cfs 50 3000 0.99 0.76 2376 6000 -3624 55 3300 0.92 0,70 2419 6600 -4181 60 3600 0.87 0.67 2487 7200 -4713 CASE 2 65 3900 0.82 0.63 2533 7800 -5267 70 4200 0.80 0,61 2654 8400 -5746 Case 2 assumes a Time of ConcentraGon less than 5 minutes so that the 75 4500 0.77 0.59 2731 9000 -6269 peak flow =.90(4.58)(Imp. Area) = 0.70 cfs 80 4800 0.75 0.57 2833 9600 -6767 85 5100 0.72 0.55 2885 10200 -7315 90 5400 0.71 0.54 3007 10800 -7793 So, the Peak flow for the Basin is the greater of the iwo flows, 95 5700 ` 0.69 0,53 3081 11400 -8319 ~ 3,04 cfs 100 6000 0.67 0.51 3145 12000 -8855 206' DRAINAGE POND CALCULATIONS Required'208' Storage Voiume = Impervious Area x,5 in ! 12 inlft 308 cu ft , '208' Volume Provided 402 cu ft DRYWELL REQUIREMENTS - 50 YEAR DESIGN STORM Maximum Storage Required by Bowstring 841 cu ft Total Storage Provided 540 cu ft Number and Type of Drywells Required 0 Single 2 Double INLAND PACIFIC ENGINEERING ' CURB DROP ANAL YSIS 1 ~ m m m m m SHELLEY LAKE 2ND ADDITION CURB INLET CALCULATIONS Curb Inlet Depression = 2 in. Standard Curb Inlet Length = 4 ft. Upstream 10 yr. Gutter Roughness Reciprocal Depth Length Curb Drop Impervious Peak Flow Slope Coeff. Cross slope of Flow Required Pond Station RIL Area c.f.s. S n Z Zln d* Qa1La** QI(QalLa) Remarks D 12+60 L 8393 1.56 0.0075 0,0160 50 3125 0.18 0.124 12.58 Need 2- 4' and 1- 5' curb inlet * Calculated per Figure 18 of Guidelines Calculatetl per Figure 16 of Guidelines A 4 foot curb drop with a 6" gutter has a . capacity of 4.0 cfs in sump condition. ~