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24968 DRAINAGE TECHNICAL REPORT ~ ~ INLAND PACI F IC E'I`J GINEERlNG, INC. ~ - - ~ ; . 7 , -,OiUd OMIStr (60. -Ad3d HOVOaddV JC] 3SV3'k3H 01 HO!E!d :.'v« `5JN1AAVkicl +Obao~d ❑3~~~~~l~~ :.rV . ' ' iif1oC]o NQI..E'.]nd1SNC7 J , I I w 3NYI 103 rOH d i dX3 30NVld 3 0:)'d .031d300V~3lVa ~ f4 irl #A -(I ~ON08d ' ~ .r IAAR 2 4 1~8 ~ SOVOU 3J.VA]Vd sN~-, rir ~ t .~r~HlSr~~3 S~E c,~ja~`f E~ '1►dN10IHD i~•~_..►~~ 3013=10 5b-D3N19N3 AiNnCYo3~MWS QFFiCf~L PUBLIC f)C?{;1jF,'4ENT ~POKAtiE r-(]'UNTV' EN'.aINH~'b- OFFIC~ ~ OR G N ~ ~ROJECTM ' 4 ~ ~ETURN TV V'l#~~~ ~~~~~~ER ~ ~POKANE # COEUR D'ALENE DRAINAGE TECHNICAL REPORT for the RIVERWALK 9TH ADDITION PUD MARCH 1998 -0 y&Z38 Prepared for: K.C. CONSTRUCTION P.O. Box 1455 Hayden Lake, Idaho 83855 Prepared By : Inland Pacific Engineering Comparry 707 W. 7th Avenue Suite 200 Spokane, WA 99204 (509) 458-6840 DRAINAGE REPORT for the Riverwalk 9th Addition PUD Plat Spokane County, Washington March 1998 I The design improvcments shown in this set of plans and calculations conform to the applicable editions of the Spokane County Standards for Road and Sewer Construction and tbe Spokane County Guidelines for Stormwater Management. All design deviations have been approved by the Spokane County Engineer. I approve these plans (calculations) for construction. This report has been prepazed by Susan K. Murphy, E.I.T. of Inland Pacific Engineering Company under the direction of the undersigned professional engineer whose seal and signature appear hereon. Todd R. Whipple, P.E. Riverwalk 9th Addition PUD Drainage Narrative GENERAL Riverwalk 9th Addition PUD Plat is a 10.88 acre development of 38 single family residential lots and 5 tract areas located north and east of the intersection of Indiana Avenue and Barker Road, witlun Spokane County, Washington. The site is currently vacant with field grass, alfalfa and fallow fields as the predominant land cover and vegetation. Single family residential development lies directly to the south and east. A vicinity and location map have been included within the technical section of this document. PURPOSE ~ The purpose of this report is to determine the extent of storm drainage facilities which will be required to dispose of the increase in stormwater runoff created by the development of the Riverwalk 9th Addition plat. The storm drainage facilities on this project will be designed to dispose of runoff from a ten year design storm, as required by the Spokane County Guidelines for Stormwater Management, though calculations are also included to verify that the facilities also contain the 50-year storm. 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 curve from the Spokane, Medical Lake, Reardon, Cheney and Rockford intensity curves was used, as well as the SCS iso-pluvial rainfall curves. A1VAL YSIS METHODOLOGY Per the Spokane County Guidelines for Stormwater Management, the Rational Method, which is recommended for basins less than ten acres in size, will be used to determine the peak discharges and runoff volumes for all onsite basins. PRUJECT DESCRIPTION This phase of the Riverwalk 9th Addition plat comprises 38 lots of the approved 393 lots in the approved preliminary plat and SEPA documents. The Riverwalk 9th Addition subdivision is located in the NE 1/4 of the SW 1/4 of Section 8, T. 25 N., R. 45 E., W.M. within Spokane County, Washington. TOPOGRAPHY The existing site naturally drains to the north and west, sloping gently towards the Spokane River from Indiana Avenue. Within the plat the natural topography was used as much as possible to Inland Pacific Engineering Comparry 1 Riverwalk 9th Addition Drainage Report I , route storm drainage. However, due to the flat slopes and the County's minimum requirements for slope, the roadway profiles have been forced down to facilitate drainage by localizing low spots for pond placement. Due to the flat slopes encountered, no concentrated pre-existing flows were observed nor were there any signs that anything other than sheet flow and ground absorption have occurred on this site. The general slopes within this plat vary from flat to nearly flat with the maximum existing slope at 0.01 ft./ft. Generally, the area within this platted portion of the overall preliminary plat would be characterized as flat. For development purposes as stated the natural sloping was used for design and is maintained as possible throughout the project. SOILS As can be seen from the accompanying soils map from the Spokane County Soils Survey as performed by the SCS, the site consists of one type of soils within the Class B type. This soil type is described as follows. GgA - Garrison gravelly loam, 0 to 5 percent slopes: Soils within this soil type are some what 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 Manap-ement indicate this to be a Soil Group Type B and pre-approved for drywell installation. Hydrologic Soil Classifccation - B DRAINAGE NARRATIVE Offsite Based upon the general geographic tendencies of this site, no appreciable amounts of offsite flows are expected for this phase. Onsite As this plat is within the aquifer sensitive azea of Spokane County all onsite drainage will be collected and treated using the "208" runoff inethod as described in the Spokane County Guidelines for Stormwater Management. To facilitate this analysis the Riverwalk 9th Addition plat was divided into 17 permanent sub-basins ( A through P). Basins have been combined where practical to utilize the same pond. Table 1 lists the basins and pond combinations for easy reference. Inland Pacific Engineering Company 2 Riverwalk 9th Addltion Drainage Report Table No. 1 WEIGHTED "C"" SUMMARY Basins Total Area Street Imp. Weighted (SF/AC) Area (SFIAC} "C" A 48590/1.12 10748/0.25 0.32 B 16900/0.39 4598/0.11 0.36 C 64650/1.48 11380/0.26 0.28 D 32500/0.75 6174/0.14 0.29 E 28040/0.64 11277/0.26 0.45 F 24650/0.57 5161 /0.12 0.31 G 27650/0.63 6092/0.14 0.32 HI, JK 60250/1.38 11470/0.26 0.29 P 13560/0.31 6502/0.15 0.51 "208" Calculations Within each basin the streets are divided into sub-basins by high and low roadway profiles. These facilities capture upstream stormwater runoff from the impervious street surface and direct the runoff into grassy '208' ponds. As shown on the '208' calculation worksheets included, the '208' storage volume provided is adequate to perform '208' treatment for the runoff created by the first half inch of rainfall. Cur6 Inlets and Catch Basin Calculations It is necessary to check the adequacy of the curb inlets, inlets or catch basins provided to divert the runoff from the gutter into the '208' ponds. Should these be required, the curb inlet calculation sheets included show the required lengths of curb openings, as well as the adequacy of the inlet grates or catch basin grates. For curb inlets greater than 4.0', either multiple curb inlets are added or the curb inlets are lengthened as required. DRAINAGE CALCULATIUNS SUMMARY Calculations have been included for Drainage Basin considerations such as Peak Flow, Time of Concentration, "208" sizing, drywell requirements, inlet sizing and curb inlets, as well as culverts Inland Pacific Engineering Company 3 Rivenvalk 9th Addition Drainage Report - , and pipe flows, some of which are summarized below with the remaining calculations included in the appendix. Within the calculation section and where it has been determined necessary for clarity, several sketches, as well as details from the plans have been incorporated to demonstrate assumptions and conclusions. BASIN DESCRIPTIONS Basins A through P Within this plat, and due to the general geographic features, several basic assumptions were followed and can be used to describe each basin. First, due to the relative flatness of the plat and project vicinity, minimum road grade is limited to 0.008 ft./ft; second, large tract ponds if practical will be used in the open space area; third, all other ponds will be of the lot pond configuration; fourth, that where practical, drywells will be minimized by combining basins and providing piping between ponds. All of these steps have been used in various basins throughout the drainage design of this project. There are four basins, L, M, N, and O which have been analyzed in the predeveloped and developed condition to verify that the developed flow is less than the predeveloped flow. The four basins are backyard areas whose natural slope directs flow away from the front yards, toward the plat boundary and is therefore not included in any of the other basins. They have been isolated and labeled on the basin map, and due to landscaping presumed to be installed in the developed condition, the runoff will be lower than the predeveloped state. No treatment is required in this condition. Inland Pacific Engineering Company 4 Riverwalk 9th Addition Drainage Repon Table No. 2- Pond and 208 Basin Summary Rivervvalk 9th Addition - BASIN SUMMARY Basin ' Pond 20$ Volume 208 Area 208 Area Drywclls Reyuired (cf) Requircd (sf) Pravided (sf)* Requirecl , A A 377 754 1147 1-"B" B B 192 3 84 422 1-"A" „ C C 474 948 992 1-"B" D D 257 514 524 1-"A" E E 470 940 975 1-"A" F F 215 430 491 1-"A" G G 254 508 593 1-"A" HI H 133 266 272 - HI I 95 190 190 - JK J 87 174 178.5 - JK K 163 326 370.5 - HI, JK - - - _ 1 _ "B„ P P 271 542 542 1-44A " `208' area is calculated as (bottom area)(0.5'); side slope volume is not included. - Type A is a Spokane Standard Drywell - Single Depth, Capacity 0.3 cfs - Type B is a Spokane Standard Drywell - Double Depth, Capacity 1.0 cfs Inland Pacific Engineering Company s Riverwalk 9th Addition Drainage Repon , Table No. 3- Curb Inlet/Catch Basin Summai-tv Xtiverwalk 8th Addition Piat - Curb Inlet and Catch Basins Summary Basin Pond Curb Inlet Catch Basin Condition Condition) ~ A A Sump - B B Sump - C C Sump Sump , D D Sump - E E Sump Sump F F Sump - G G Sump - HI H Continuous - , HI I Sump - JK J Sump - JK K Continuous - P P Continuous - Per Spokane County Guidelines curb drops in a sump condition have a capacity of 4.0 cfs Per WSDOT Hydraulics Manual, Grate Inlet, has a sump capacity of 13.0 cfs NOTE: Only curb drop and grate calculations were performed for those cases "On Grade"; cur6 drops and catch basins in sump condition are assumed to handle 4.0 cfs. Inland Pacific Engineering Comparry 6 Riverwalk 9th Addition Drainage Report - _ - / Yr~W1~ 11w_ - t . ' ~1ap ~'N' J er 1: ~ 290 ~ Pe~s~eo Oa~s A+e. ~ ~ . cw. a ~ 1i w ~ ~ ~ ~ i ~ ~ ~ ~ ~ 3 ~ ci ~ or.«... ; M.e..a ~ .M~ TAM~... t~M lrMd Ma ~ WeN~let Aw- pIhM~My Aw. MW p VAL* #A... c) fis c)rrfi:ir 1s ~ ~ . a - . . . w~.~e.... Cr4M Mt. • ~ j ~ P IO J T ' . / ~ • . LIPCA ION . fC Cl ~ ~ ~ A... _ ~ I • t Ave. ~ O Sp c ~i f ~ A V ~v wubn ~w. ~ M+tlen An. , Wew11Aa. d ~ w Av1. Lin1~ ~w. 3 ~ . ~++g• VatleY Vlew : ` .~.~+pi' s..~. ~ ~ cr ~ Golf Caurse ~ ,~sL"' aA.w. w.. ~ ►vd`M ` f ' . wf • MaadowWood ~ Golf Caurse G 1'•l`il Al'i'Cti a ~ Poat nw,wF Ot(lce a~.ov Uberty Uke a ' S PubNc Goll Course Ya a jK. ~ ~ 1~ Aw, t H1 Mr. A i b~d . 1sIAw ZS iC 'M~O~ ~ t l~,~b'L Me. ~ _ ~ j~, ~ e..4,. a. .r N~ A~r j~ ~ p / a ~ Cr,uer. q is d ~ . ~ ~ ywvM. oc ~ ~ Posl . Q11tce ~ M* ►w. , ~ MI~ Aw. ' . l.illrrh' l.;il:c ~ a~ G~ ` ~ u~r + . . Weighted Runoff Coefficient Calculation Project: Riverwalk 9th Addition Basin: A IPE Job 96238 Total Area (acres): 1.12 Designer: SKM Imp. Area (acres): 0.25 Date: 09/22 Grass Area (acres): 0.87 Imp. Area "C": 0.90 Grass Area "C": 0.15 (Imp. Area)(Imp. "C")= 0.2250 (Grass Area)(Grass "C")= 0.1305 1.1200 0.3555 Weighted "C"= 0.3555 0.32 1.1200 Weighted Runoff Coefficient Calculation Project: Riverwalk 9th Addition Basin: B IPE Job 95238 Total Area (acres): 0.39 Designer: SKM Imp. Area (acres): 0.11 Date: 09/22 Grass Area (acres): 0.28 Imp. Area "C": 0.90 Grass Area "C": 0.15 (Imp. Area)(Imp. "C")= 0.0990 (Grass Area)(Grass "C")= 0.0420 0.3900 0.1410 Weighted "C"= 0.1410 0.36 0.3900 Weighted Runoff Coefficient Calculation Project: Rivenn►alk 9th Addition Basin: C IPE Job 96238 Total Area (acres): 1.48 Designer: SKM Imp. Area (acres): 0.26 Date: 09/22 Grass Area (acres): 1.22 Imp. Area "C": 0.90 Grass Area "C": 0.15 (Imp. Area)(Imp. "C")= 0.2340 (Grass Area)(Grass "C")= 0.1830 1.4800 0.4170 Weighted "C"= 0.4170 0.28 1.4800 Weighted Runoff Coefficient Calculation Project: Riverwalk 9th Addition Basin: D IPE Job 96238 Total Area (acres): 0.75 Designer: SKM Imp. Area (acres): 0.14 Date: 09/22 Grass Area (acres): 0.61 Imp. Area "C": 0.90 G rass Area "C": 0.15 (Imp. Area)(Imp. "C")= 0.1260 (Grass Area)(Grass "C")= 0.0915 0.7500 0.2175 Weighted "C"= 0.2175 0.29 0.7500 Weighted Runoff Coefficient Calculation Project: Riverwalk 9th Addition Basin: E IPE Job 96238 Total Area (acres): 0.64 Designer: SKM Imp. Area (acres): 0.26 Date: 09/22 Grass Area (acres): 0.38 Imp. Area "C": 0.90 Grass Area "C": 0.15 (Imp. Area)(Imp. "C")= 0.2340 (Grass Area)(Grass "C")= 0.0570 o.s4oo 0.2910 Weighted "C"= 0.2910 0.45 0.6400 Weighted Runoff Coefficient Calculation Project: Riverwalk 9th Addition Basin: F IPE Job 96238 Total Area (acres): 0.57 Designer: SKM Imp. Area (acres): 0.12 Date: 09/22 Grass Area (acres): 0.45 Imp. Area "C": 0.90 Grass Area "C": 0.15 (Imp. Area)(Imp. "C")= 0.1080 (Grass Area)(Grass "C")= 0.0675 0.5700 0.1755 Weig hted "C"= 0.1755 0.31 0.5700 Weighted Runoff Coefficient Calculation Project: Riverwalk 9th Addition Basin: G IPE Job 96238 Total Area (acres): 0.63 Designer: SKM Imp. Area (acres): 0.14 Date: 09/22 Grass Area (acres): 0.49 Imp. Area "C": 0.90 Grass Area "C": 0.15 (Imp. Area)(Imp. "C"}= 0.1260 (Grass Area)(Grass "C")= 0.0735 0.6300 0.1995 Weighted "C"= 0.1995 0.32 0.6300 Weighted Runoff Coefficient Calculation Project: Riverwalk 9th Addition Basin: H IPE Job 96238 Total Area (acres): 0.07 Designer: SKM Imp. Area (acres): 0.07 Date: 09122 Grass Area (acres): 0.00 Imp. Area "C": 0.90 Grass Area "C": 0.15 (Imp. Area)(Imp. "C")= 0.0630 (Grass Area)(Grass "C")= 0.0000 0.0700 0.0630 Weighted "C"= 0.0630 0.90 0.0700 Weighted Runoff Coefficient Calculation Project: Riverwalk 9th Addition Basin: I IPE Job 96238 Total Area (acres): 0.46 Designer: SKM Imp. Area (acres): 0.13 Date: 09/22 Grass Area (acres): 0.33 Imp. Area "C": 0.90 Grass Area "C": 0.15 (Imp. Area)(Imp. "C")= 0.1170 (Grass Area)(Grass C")_ - 0.0495 ~ 0.4600 0.1665 Weighted "C"= 0.1665 0.36 0.4600 Weighted Runoff Coefficient Calculation Project: Riverwalk 9th Addition Basin: J IPE Job 96238 Total Area (acres): 0.92 Designer: SKM Imp. Area (acres): 0.14 Date: 09/22 Grass Area (acres): 0.78 Imp. Area "C": 0.90 Grass Area "C": 0.15 (Imp. Area)(Imp. "C")= 0.1260 (Grass Area)(Grass "C")= 0.1170 ~ 0.9200 0.2430 Weighted "C"= 0.2430 0.26 0.9200 Weighted Runoff Coefficient Calculation Project: Riverwalk 9th Addition Basin: K I PE Job 96238 Total Area (acres): 0.09 Designer: SKM Imp. Area (acres): 0.09 Date: 09/22 Grass Area (acres): 0.00 Imp. Area "C": 0.90 Grass Area "C": 0.15 (Imp. Area)(Imp. "C")= 0.0810 (Grass Area)(Grass "C")= 0.0000 0.0900 0.0810 Weighted "C"= 0.0810 0.90 0.0900 Weighted Runoff Coefficient Catculation Project: Riverwalk 9th Addition Basin: HI & JK IPE Job 96238 Total Area (acres): 1.38 Designer: SKM Imp. Area (acres): 0.26 Date: 09/16 Grass Area (acres): 1.12 Imp. Area "C": 0.90 Grass Area "C": 0.15 (imp. Area)(Imp. "C")= 0.2340 (Grass Area)(Grass "C")= 0.1680 1.3800 0.4020 Weig hted "C"= 0.4020 0.29 1.3800 Weighted Runoff Coefficient Calculation Project: Riverwalk 9th Addition Basin: P IPE Job 96238 Total Area (acres): 0.31 Designer: SKM Imp. Area (acres): 0.15 Date: 03/19 Grass Area (acres): 0.16 Imp. Area "C": 0.90 Grass Area "C": 0.15 (Imp. Area)(Imp. "C")= 0.1350 (Grass Area)(Grass "C")= 0.0240 0.3100 0.1590 Weighted "C"= 0.1590 0.51 0.3100 BOWSTRING METHOD PROJECT: Riverwalk 9th Addition PEAK FLOW CALCULATION PROJECT Riverwalk 9th Addition DETENTION BASIN DESIGN BASIN: A BASIN: A 10-Year Design Storm DESIGNER: S. Murphy Tot. Area 1.12 Acres DATE: 09122 Imp. Area 10748 SF C = 0.32 Time Increment (min) 5 CASE 1 Time of Conc. (min) 7.00 Outflow (cis) 1 120 ft. Overiand Flow Design Year Flow 10 Area (acres) 1.12 Cl = 0.15 Impervious Area (sq ft) 10748 L= 120 ft. 'C' Factor 0.32 n= 0.40 '208' Volume Provided 573.5 S= 0.020 Area' C 0.358 Tc = 4.95 min., by Equation 3-2 of Guidelines Time Time Inc. Intens. Q Devel, Vol.ln Vol.Out Storege 202 ft. Gutter flow (min) (sec) (iNhr) (cfs) (cu ft) (cu ft) (cu ft) - - Z1= 50.0 For Z2 7.00 420 2.68 0.96 541 420 121 Z2 = 3.5 Type B =1.0 n= 0.016 Rolled = 3.5 5 300 3.18 1.14 458 300 158 S= 0.010 10 600 224 0.80 596 600 -4 15 900 1.77 0.63 662 900 -238 d= 0.148 ft. 20 1200 1.45 0.52 698 1200 -502 25 1500 1.21 0.43 112 1500 -788 A R Q Tc Tc total I Qc 30 1800 1.04 0.37 724 1800 -1076 35 2100 0.91 0.33 732 2100 -1368 0.59 0.07 0.96 2.05 7.00 2.68 0.96 40 2400 0.82 0.29 747 2400 -1653 45 2700 0.74 0.27 754 2700 -1946 Qpeak for Case 1= 0.96 ds 50 3000 0.66 0.24 766 3000 -2234 55 3300 0.64 0.23 790 3300 -2510 60 3600 0.61 0.22 818 3600 -2782 CASE 2 65 3900 0.60 4.22 669 3900 -3031 70 4200 0.58 0.21 903 4200 -3297 Case 2 assumes a Time of Concentratian less than 5 minutes so that the 75 4500 0.56 020 932 4500 -3568 peak flow =.90(3.18)(Imp. Area) = 0.71 cfs 80 4800 0.53 0.19 939 4800 -3861 85 5100 0,52 0.19 977 5100 -4123 90 5400 0.50 0.18 993 5400 -4407 So, the Peak flow for the Basin is the greater of the two flows, 95 5700 0.49 0.18 1026 5700 -4674 0.96 cfs 100 6000 0.48 0.17 1057 6000 -4943 208' DRAINAGE POND CALCULATIONS Required'208' Storage Volume = Impervious Area x.5 in I 12 inlft 448 cu ft 208' Storage Volume Provided 573.5 cu ft DRYVNELL REQUIREMENTS -10 YR. DESIGN STORM Maximum Storage Required by Bowstnng 158 cu ft Number and Type of Drywells Required 0 Single 1 Double BOWSTRING METHOD PROJECT: Riverwalk 9th Addition PEAK FLOW CALCULATION PROJECT Riverwalk 9th Addition DETENTION BASIN DESIGN BASIN: B BASIN: B 10-Year Design Storm DESIGNER: S. Murphy Tot. Area 0.39 Acres DATE: 09115 Imp.Area 4598 SF C = 0.36 Time Increment (min) 5 CASE 1 Time of Conc. (min) 6,59 Outflow (cfs) 0.3 65 ft, Overiand Flow Design Year Flow 10 Area (acres) 0.39 Ct = 0.15 Impenrious Area (sq ft) 4598 L= 65 ft. 'C' Faclor 0,36 n= 0.40 '208' Volume Provided 211 S= 0.020 Area ' C 0.140 Tc = 3.43 min., by Equation 3-2 of Guidelines Time Time Inc. Intens. Q Devel, Vol.ln Vol.Out Storage 249 ft. Gutter flow (min) (sec) (iNhr) (cfs) (cu ft) (cu fl) (cu ft) Z1= 50.0 For Z2 6.59 395 2.75 0,39 205 119 86 Z2 = 3.5 Type B =1.0 n= 0.016 Rolled = 3.5 5 300 3.18 0.45 179 90 89 S= 0.010 10 600 2.24 0.31 231 180 51 15 900 1.77 0.25 257 270 -13 d= 0.106 fl. 20 1200 1.45 0,20 272 360 -88 25 1500 1.21 0.17 218 450 -172 A R Q Tc Tc total I Qc 30 1800 1.04 0.15 282 540 -258 35 2100 0.91 0.13 285 630 -345 0.30 0,05 0.39 3.16 6.59 2.75 0.39 40 2400 0.82 0.12 292 720 -428 45 2700 0.74 0.10 294 810 -516 Qpeak for Case 1= 0.39 cfs 50 3000 0.68 0.10 299 900 -601 55 3300 0.64 0.09 309 990 -681 60 3600 0.61 0.09 320 1080 -760 CASE 2 65 3900 0.60 0.08 340 1170 -830 70 4200 0.58 0.08 353 1260 -907 Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.56 0.08 364 1350 -986 peak flow =.90(3.18)(Imp. Area) = 0.30 cfs 80 4800 0.53 0,07 367 1440 -1073 85 5100 0.52 0.07 382 1530 -1148 90 5400 0.50 0.07 389 1620 -1231 So, the Peak flow for the Basin is the greater of the two flows, 95 5700 0.49 0.07 401 1710 -1309 0.39 cfs 100 6000 0.48 0.07 413 1800 -1387 208' DRAINAGE POND CALCULATIONS Required '208' Storage Volume = Impenrious Area x.5 in /12 iNfl 192 cu ft 208' Storage Vatume Provided 211 cu ft DRYWELL REQUIREMENTS -10 YEAR DESIGN STORM Maximum Storage Required by Bowstring 89 cu fl Number and Type oi Drywells Required 1 Single 0 Double BOWSTRING METHOD PROJECT: Rivenrralk 9th Addition PEAK FLOW CALCULATION PROJECT Riverwalk 9th Addition DETENTION BASIN DESIGN BASIN: C BASIN: C 10-Year Design Storm DESIGNER: S. Murphy Tot. Area 1.48 Acres DATE: 09115 Imp. Area 11380 SF C = 0.28 Time inaement (min) 5 CASE 1 Time of Conc. (min) 6.96 Outflow (cfs) 1 50 ft. Overland Flow Design Year Flow 10 Area (acres) 1.48 Ct = 0.15 Imperoious Area (sq ft) 11380 L= 50 ft. 'C' Factor 0,28 n= 0.40 '208' Volume Provided 496 S= 0.020 Area' C 0.414 Tc = 2.93 min., by Equaiion 3-2 of Guidelines Time Time Inc. Intens. Q Devel. Val.ln Vol.Out Storage 447 fl. Gutter flow (min) (sec) (inlhr) (cfs) (cu ft) (cu ft) (cu ft) Z1= 50.0 For Z2 6.96 417 2.69 1.11 623 417 206 Z2 = 3.5 Type B =1.0 n= 0.016 Rolled = 3.5 5 300 3.18 1.32 530 300 230 S= 0.013 10 600 2.24 0.93 689 600 89 15 900 1.77 0.73 764 900 -136 d= 0.150 ft. 20 1200 1.45 0.60 806 1200 -394 25 1500 1.21 0.50 823 1500 -671 A R Q Tc Tc total I Qc 30 1800 1.04 0,43 837 1800 -963 35 2100 0.91 0.38 845 2100 -1255 0.60 0.07 1.11 4.03 6.96 2.69 1.11 40 2400 0.82 0.34 864 2400 -1536 45 2100 0.74 0.31 871 2700 -1829 Qpeak for Case 1= 1.11 cfs 50 3000 0.68 0.28 885 3000 -2115 55 3300 0.64 0.27 913 3300 -2387 60 3600 0.61 0.25 946 3600 -2654 CASE 2 65 3900 0.60 0.25 1005 3900 -2895 70 4200 0.58 0.24 1044 4200 -3156 Case 2 assumes a Time of Concentration less than 5 minutes so that lhe 75 4500 0.56 0.23 1077 4500 -3423 peak flow =.90(3.18)(Imp. Area) = 0.75 cfs 80 4800 0.53 0.22 1085 4800 -3715 85 5100 0.52 0.22 1130 5100 -3970 90 5400 0.50 0.21 1148 5400 -4252 So, the Peak flow for the Basin is the greater of the two Flows, 95 5700 0,49 0.20 1186 5700 -4514 1.11 cfs 100 6000 0.48 0.20 1222 6000 -4778 208' DRAINAGE POND CALCULATIONS Required '208' Storage Volume = Impervious Area x.5 in I 12 iNft 474 cu ft 208' Storage Volume Provided 496 cu ft DRYWELL REQUIREMENTS -10 YEAR DESIGN STORM Maximum Storage Required by Bowstring 230 cu ft Number and Type of Drywells Required 0 Single 1 Double BOWSTRING METHOD PROJECT: Riverwalk 9th Addition PEAK FLOW CALCULATION PROJECT Riverwalk 9th Addition DETENTION BASIN DESIGN BASIN: D BASIN: D 10-Year Design Stortn DESIGNER: S. Murphy Tot. Area 0.75 Acres DATE: 09J15 Imp. Area 6174 SF C = 0.29 Time Increment (min) 5 CASE 1 Time of Canc. (min) 6.87 Outflow (cfs) 0.3 120 ft. Overland Flow Design Year Flow 10 Area (acres) 0.75 Ct = 0.15 Impervious Area (sq ft) 6174 L= 120 ft. 'C' Facta 0.29 n= 0.40 '208' Volume Provided 262 S= 0.020 Area' C 0.217 Tc = 4.95 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) (cts) (cu ft) (cu ft) (cu R) Z1= 50.0 For 72 6.87 412 2.70 0.59 325 124 201 Z2 = 3.5 Type B =1.0 n= 0.016 Rolled = 3.5 5 300 3.18 0.69 278 90 188 S= 0.016 10 600 2.24 0.49 361 180 181 15 900 1.77 0.38 400 270 130 d= 0.113 ft. 20 1200 1.45 0.32 423 360 63 25 1500 1.21 0.26 432 450 -16 A R Q Tc Tc total I Qc 30 1800 1.04 0.23 439 540 -101 35 2100 0.91 0.20 443 630 -187 0.34 0.06 0.59 1.93 6.87 2.70 0.59 40 2400 0.82 0.18 453 720 _267 45 2700 0.74 0.16 457 810 -353 Qpeak for Case 1= 0.59 cfs 50 3000 0.68 0.15 464 900 -436 55 3300 0.64 0.14 479 990 -511 60 3600 0.61 0.13 496 1080 -584 CASE 2 65 3900 0.60 0,13 527 1170 -643 70 4200 0.58 0.13 548 1260 -712 Case 2 assumes a Time of Concentration less lhan 5 minutes so lhat the 75 4500 0.56 0,12 565 1350 -785 peak Bow =.90(3.18)(Imp. Area) = 0.41 cfs 60 4800 0.53 0.12 569 1440 -871 85 5100 0.52 0.11 593 1530 -937 90 5400 0.50 0.11 603 1620 -1017 So, the Peak flow for lhe Basin is the greater of the two flows, 95 5700 0.49 0.11 622 1710 •1088 0 59 cis 100 6000 0.48 0.10 641 1800 -1159 208' DRAINAGE POND CALCULATIONS Required'208' Storage Volume = Impervious Area x.5 in 112 inlft 257 cu ft 208' Storage Volume Provided 262 cu ft DRYWELL REQUIREMENTS -10 YEAR DESIGN STORM Maximum Storage Required by Bowstring 201 cu fl Number and Type of Drywells Required 1 Single 0 Double BOWSTRING METHOD PROJECT: Riverwalk 9th Addition PEAK FLOW CALCULATION PROJECT Riverwalk 9th Addition DETENTION BASIN DESIGN BASIN: E BASIN: E 10-Year Design Storm DESIGNER: S. Murphy Tot. Area 0.64 Acres DATE: 03123 Imp. Area 11277 SF C = 0.45 Time Increment (min) 5 CASE 1 Time of Conc, (min) 5.00 Outflow (cfs) 0.3 17 ft. Overland Flow Design Year Flow 10 Area (acres) 0.64 Ct = 0.15 Impervious Area (sq ft) 11277 L= 17 ft. 'C' Factor 0.45 n= 0.02 '208' Volume Provided 487.5 S= 0.020 Area' C 0.288 Tc = 0.22 min., by Equation 3-2 of Guidelines Time Time Inc. Intens. Q Devel. Vol.ln Vol.Out Storage 135 ft. Gutter flow (min) (sec) (iNhr) (cfs) (cu ft) (cu ft) (cu ft) Z1 = 50,0 For Z2 5.00 300 3,18 0.92 368 90 278 Z2 = 3.5 Type B =1.0 n= 0.016 Rolled = 3.5 5 300 3.18 0.92 368 90 278 S= 0.010 10 600 2.24 0,65 453 180 273 15 900 1.77 0.51 511 270 241 d= 0.146 ft. 20 1200 1.45 0,42 544 360 184 25 1500 121 0.35 558 450 108 A R Q Tc Tc total I Qc 30 1800 1.04 0.30 570 540 30 35 2100 0.91 0.26 577 630 -53 0.57 0.07 0.92 1,39 5.00 3.18 0.92 40 2400 0.82 0.24 591 720 -129 45 2700 0.74 0.21 597 610 -213 Qpeak for Case 1= 0.92 cfs 50 3000 0.68 0.20 607 900 -293 55 3300 0.64 0.18 627 990 -363 60 3600 0.61 0.18 650 1080 -430 CASE 2 65 3900 0.60 0.17 692 1110 -478 70 4200 0,58 0.17 719 1260 -541 Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.56 0.16 742 1350 -608 peak flow =.90(3.18)(Imp. Area) = 0.74 cfs 80 4800 0.53 0.15 748 1440 -692 85 5100 0.52 0.15 719 1530 -751 90 5400 0.50 0.14 792 1620 -828 So, the Peak flow for the Basin is the greater of the two flows, 95 5700 0.49 0.14 819 1710 -891 0.92 cfs 100 6000 0.48 0.14 844 1800 -956 208' DRAINAGE POND CALCULATIONS Required'208' Storage Volume = Impervious Area x.5 in 112 inlft 470 cu ft 208' Storage Volume Provided 487.5 cu ft DRYWELL REQUIREMENTS -10 YEAR DESIGN STORM Maximum Storage Required by Bowstring 278 cu ft Number and Type of Drywells Required 1 Single 0 Double BOWSTRING METHOD PROJECT: Riverwalk 9th Addition PEAK FLOW CALCULATION PROJECT Riverwalk 9lh Addition DETENTION BASIN DESIGN BASIN: F BASIN F 10-Year Design Storm DESIGNER: S. Murphy Tot. Area 0.57 Acres DATE: 09115 Imp. Area 5161 SF C = 0.31 Time Increment (min) 5 CASE 1 Time of Conc. (min) 5.95 Outflow (cfs) 0.3 140 ft. Overland Flow Design Year Flow 10 Area (acres) 0.57 Ct = 0,15 Impenrious Area (sq ft) 5161 L= 100 ft. 'C' Factor 0.31 n= 0.40 '208' Volume Provided 223.5 S= 0.020 Area' C 0.177 Tc = 4.44 min., by Equation 3-2 of Guidelines Time Time Inc. Intens, Q Devel. Vol.ln Vol.Out Storage 146 fl. Gutter flow (min) (sec) (iNhr) (cis) (cu ft) (cu ft) (cu ft) - Z1= 50.0 ForZ2 5.95 357 2,90 0.51 246 107 139 Z2 = 3.5 Type B =1.0 n= 0.016 Rolled = 3.5 5 300 3,18 0.56 226 90 136 S= 0.014 10 600 224 0.40 286 180 106 15 900 1.77 0.31 319 270 49 d= 0.109 ft. 20 1200 1.45 0.26 339 360 -21 25 1500 121 0.21 347 450 -103 A R Q Tc Tc total I Qc 30 1800 1.04 0.18 353 540 -187 - - - 35 2100 0.91 0.16 357 630 -273 0.32 0.05 0.51 1.52 5.95 2.90 0.51 40 2400 0.82 0,14 365 720 -355 45 2700 0.74 0,13 369 810 -441 Qpeak for Case 1= 0.51 cfs 50 3000 0.68 0,12 375 900 -525 55 3300 0.64 0.11 387 990 -603 60 3600 0.61 0.11 401 1080 -679 CASE 2 65 3900 0.60 0.11 426 1170 -744 70 4200 0.58 0.10 443 1260 -817 Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.56 0.10 457 1350 -893 peak flow =.90(318)(Imp. Area) = 0.34 cfs 80 4800 0.53 0.09 461 1440 -979 85 5100 0.52 0.09 480 1530 -1050 90 5400 0.50 0.09 488 1620 -1132 So,1he Peak flow for lhe Basin is the greater of the two flows, 95 5700 0.49 0.09 504 1710 -1206 0.51 cfs 100 saoa 0.48 0.08 519 1600 -1281 208' DRAINAGE POND CALCULATIONS Required'208' Storage Volume = Imperoious Area x.5 in ! 12 in/ft 215 cu ft 208' Storage Volume Provided 223.5 cu ft DRYWELL REQUIREMENTS -10 YEAR DESIGN STORM Maximum Storage Required by Bowstring 139 cu fl Number and Type of Drywells Required 1 Single 0 Double BOWSTRING METHOD PROJECT: Riverwalk 81h AddiGon PEAK FLOW CALCULATION PROJECT Riverwalk Sth Addition DETENTION BASIN DESIGN BASIN: G BASIN: G 10•Year Design Storm DESIGNER: S. Murphy Tot. Area 0.63 DATE: 09115 Imp. Area 6092 SF C = 0.32 Time Increment (min) 5 CASE 1 Time of Conc. (min) 5.00 Outflow (cfs) 0.3 50 ft. Overland Flow Design Year Flow 10 Area (acres) 0.63 Ct = 0.15 Impervious Area (sq ft) 6092 L= 50 ft. 'C' Factor 0.32 n= 0.40 '208' Volume Provided 296.5 S= 0.020 Area' C 0.202 Tc = 2.93 min., by Equation 3-2 of Guidelines Time Time Inc. Intens. Q Devel, Vol.ln Vol.Out Storage 210 ft. Gutter flow (min) (sec) (iNhr) (cfs) (cu ft) (cu ft) (cu ft) Z1 = 50.0 For Z2 5.00 300 3.18 0.64 258 90 168 Z2 = 3.5 Type B =1.0 n= 0.016 Rolled = 3,5 5 300 3.18 0,64 258 90 168 S= 0.016 10 600 224 0.45 317 180 137 15 900 1,77 0.36 358 270 88 d= 0.117 ft. 20 1200 1.45 0.29 381 360 21 25 1500 1.21 024 391 450 -59 A R Q Tc Tc total I Qc 30 1800 1.04 0.21 399 540 -141 35 2100 0,91 0.18 404 630 -226 - - - 0.36 0.06 0,64 1.98 5.00 3.18 0.64 44 2400 0.82 0,17 414 720 -306 45 2700 0.74 0.15 418 810 -392 Qpeak 1or Case 1= 0.64 cfs 50 3000 0.68 0.14 425 900 -475 55 3300 0.64 0.13 439 990 -551 60 3600 0.61 0.12 455 1080 -625 CASE 2 65 3900 0.60 0.12 484 1170 -686 70 4200 0.58 0,12 503 1260 -757 Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.56 0,11 520 1350 -830 peak flow =.90(3.18)(Imp. Area) = 0.40 cfs 80 4840 0.53 0.11 524 1440 -916 85 5100 0.52 0.10 545 1530 -985 90 5400 0.50 0.10 555 1620 -1065 So, the Peak flow for the Basin is the greater of the rivo flows, 95 5700 0.49 0.10 573 1710 -1137 0.64 cfs 100 6000 0.48 0.10 590 1800 -1210 208' DRAINAGE POND CALCULATIONS Required'208' Storage Volume = Impervious Area x.5 in ! 12 inlft 254 cu ft 208' Storage Volume Provided 296.5 cu ft ORYWELL REQUIREMENTS -10 YEAR DESIGN STORM Maximum Storage Required by Bowstring 168 cu ft Number and Type of Drywells Required 1 Single 0 Double BOWSTRING METHOD PROJECT: Rivervvalk 9th Addition PEAK FLOW CALCULATION PROJECT Riverwalk 9th Addition DETENTION BASIN DESIGN BASIN: H BASIN: H 10-Year Design Storm DESIGNER: S. Murphy Tot. Area 0.01 Acres DATE: 09116 Imp. Area 3188 SF C = 0.90 Time Increment (min) 5 CASE 1 Time of Conc. (min) 5.00 Outflow (cfs) 0 40 ft. Overland Flow Design Year Flow 10 Area (aaes) 0.07 Ct = 0.15 Impervious Area (sq ft) 3188 L= 40 ft. 'C' Factor 0.9 n= 0.40 '208' Volume Provided 136 S= 0.020 Area " C 0.063 Tc = 2.56 min., by Equation 3-2 of Guidelines Time Time Inc. Intens. Q Devel. Vol.ln Vol.Out Storage 143 ft. Gutter flow (min) (sec) (iNhr) (cfs) (cu ft) (cu ft) (cu ft) Z1= 50.0 FotZ2 5.00 300 3.18 0.20 81 0 81 Z2 = 3.5 Type B =1.0 n= 0.016 Rolled = 3.5 5 300 3.18 0.20 81 0 81 S= 0.011 10 600 2.24 0.14 99 0 99 15 900 1.77 0.11 112 0 112 d= 0.080 ft. 20 1200 1.45 0.09 119 0 119 25 1500 1.21 0.08 122 0 122 A R Q Tc Tc total I Qc 30 1800 1.04 0.07 125 0 125 35 2100 0.91 0.06 126 0 126 - - - 0.17 0.04 0.20 2.09 5.00 3.18 0.20 40 2400 0.82 0.05 129 0 129 45 2700 0.74 0.05 131 0 131 Qpeak for Case 1= 020 cfs 50 3000 0.68 0.04 133 0 133 55 3300 0.64 0.04 137 0 137 60 3600 0.61 0.04 142 0 142 CASE 2 65 3900 0.60 0.04 151 0 151 70 4200 0.58 0.04 157 0 157 Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.56 0.04 162 0 162 peak Oow =.90(3,18)(Imp. Area) = 0.21 cfs 80 4800 0.53 0.03 164 0 164 85 5100 0.52 0,03 170 0 170 90 5400 0.50 0,03 173 0 173 So, the Peak flaw for the Basin is the greater of the iwo flows, 95 5700 0.49 0.03 179 0 179 0.21 cfs 100 6000 0.48 0,03 185 0 185 208' DRAINAGE POND CALCULATIONS Required'208' Storage Volume = Imperoious Area x.5 in 112 iNft 133 cu ft 208' Storage Volume Prov'rded 136 cu ft DRWVELL REQUIREMENTS -10 YEAR DESIGN STOR Maximum Storage Required by Bowstring 170 cu ft Number and Type of Drywells Required ERR Single ERR Double BOWSTRING METHOD PROJECT: Riverwalk 9th Addition PEAK FLOW CALCULATION PROJECT Riverwalk 9th Addiiion DETENTION BASIN DESIGN BASIN: I BASIN I 10-Year Oesign Storm DESIGNER: S. Murphy Tot. Area 0.46 Aaes DATE: 09118 Imp. Area 5472 SF C = 0.36 Time Increment (min) 5 CASE 1 Time of Conc. (min) 5.43 Outflow (cfs) 0.3 40 ft. Overland Flow Design Year Flow 10 Area (acres) 0.46 Ct = 0.15 Impervious Area (sq ft) 5472 L= 40 ft. 'C Factor 0.36 n= 0.40 '208' Volume Provided 231 S= 0.020 Area ' C 0.166 Tc = 2.56 min., by Equation 3-2 of Guidelines Time Time Inc. Intens. Q Devel. Vol.ln Vol.Out Storage 250 ft. Gutter flow (min) (sec) (inmr) (cfs) (cu ft) (cu ft) (cu ft) Z1= 50.0 For Z2 5.43 326 3.07 0.51 222 98 124 Z2 = 3.5 Type B =1.0 n= 0.016 Rolled = 3.5 5 300 3.18 0.53 212 90 122 S= 0.011 10 600 2.24 0.37 264 180 84 15 900 1.77 0.29 296 270 26 d= 4.115 ft, 20 1200 1.45 0.24 315 360 -45 25 1500 1.21 0.20 323 450 -127 A R Q Tc Tc total I Qc 30 1800 1.04 0.17 329 540 -211 35 2100 0.91 0.15 333 630 -297 0.35 0.06 0.51 2.87 5.43 3.07 0.51 40 2400 0.82 0.14 341 720 -379 45 2700 0.74 0.12 344 810 -466 Qpeak for Case 1= 0,51 cfs 50 3000 0.68 0.11 350 900 -550 55 3300 0.64 0.11 361 990 -629 60 3600 0.61 0.10 375 1080 -705 CASE 2 65 3900 0.60 0.10 399 1170 -771 70 4200 0,58 0.10 414 1260 -846 Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.56 0.09 428 1350 -922 peak flow =.90(3.18)(Imp. Area) = 0.36 cfs 80 4800 0.53 0.09 431 1440 -1009 85 5100 0.52 0.09 449 1530 -1081 90 5400 0.50 0.08 456 1620 -1164 So, the Peak flow for the Basin is the greater of the lwo flows, 95 5100 0.49 0,08 472 1710 -1238 0.51 cfs 100 6000 0.48 0.08 486 1800 -1314 ' 208' DRAINAGE POND CALCULATIONS Required'208' Storage Volume = Impervious Area x.5 in 112 iNft 218 cu ft 208' Storage Volume Provided 231 cu fl DRYWELL REQUIREMENTS -10 YEAR DESIGN STORM Maximum Slorage Required by Bowstring 124 cu ft Number and Type of Drywells Required 1 Single 0 Double BOWSTRING METH00 PROJECT: Riverwalk 9th Addition PEAK FLOW CALCULATION PROJECT Rivervwalk 9th Addition DETENTION BASIN DESIGN BASIN: J BASIN; J 10-Year Design Stonn DESIGNER: S. Murphy Tot. Area 0.92 Acres DATE: 09115 Imp. Area 5998 SF C = 0.14 Time Inaement (min) 5 CASE 1 Time of Conc. (min) 6.84 Outflow (cfs) 0,3 50 ft, Overland Flow Design Year Flow 10 Area (acres) 0.92 Ct = 0.15 Impenrious Area (sq ft) 5998 L= 50 ft. 'C' Fador 0.14 n= 0,40 '208' Volume Provided 274.5 S= 0.020 Area " C 0.129 Tc = 2.93 min., by Equation 3-2 of Guidelines Time Time Inc. Intens. Q Devel. Val.ln Vol.Out Storage 311 fl. Gutter flow (min) (sec) (iNhr) (cfs) (cu ft) (cu fl) (cu ft) Z1 = 50.0 For Z2 6.84 411 2.71 0.35 192 123 69 Z2 = 3.5 Type B =1.0 n= 0.016 Rolled = 3.5 5 300 3.18 0.41 165 90 75 S= 0.011 10 600 2.24 0.29 213 180 33 15 900 1.77 0.23 237 270 -33 d= 0.100 fl. 20 1200 1.45 0.19 250 360 -110 25 1500 1.21 0.16 256 450 -194 A R Q Tc Tc total I Qc 30 1800 1.04 0.13 260 540 -280 35 2100 0.91 0.12 263 630 -367 0,27 0.05 0,35 3.92 6.84 2,71 0.35 40 2400 0.82 0.11 268 720 -452 45 2700 0.74 0.10 271 810 -539 Qpeak for Case 1= 0.35 cfs 50 3000 0.68 0.09 275 900 -625 55 3300 0.64 0.08 284 990 -706 60 3600 0.61 0.08 294 1080 -786 CASE 2 65 3900 0.60 0.08 312 1170 -858 70 4200 0.58 0.07 324 1260 -936 Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.56 0.07 335 1350 -1015 peak flow =.90(3.18)(Imp. Area) = 0.39 cfs 80 4800 0.53 0.07 337 1440 -1103 85 5100 0.52 0.07 351 1530 -1179 90 5400 0.50 0.06 357 1620 -1263 So, the Peak flow for the Basin is the greater of the two flows, 95 5700 0.49 0.06 369 1710 -1341 0.39 cfs 100 6000 0.48 0.06 380 1800 -1420 208' DRAINAGE POND CALCULATIONS Required'208' Storage Volume = Impervious Area x.5 in I 12 iNft 250 cu ft 208' Storage Volume Provided 274.5 cu ft DRYWELL REQUIREMENTS -10 YEAR DESIGN STORM Maximum Storage Required by Bowstring 75 cu ft Number and Type oi Drywells Required 1 Single 0 Double BOWSTRING METHOD PROJECT: Riverwalk 9th Addition PEAK FLOW CALCULATION PROJECT Riverwalk 9th Addition OETENTION BASIN DESIGN BASIN: K BASIN: K 10-Year Design Stortn DESIGNER: S. Murphy Tot. Area 0,09 Acres DATE: 09J15 Imp. Area 3908 SF C = 0,90 Time Inaement (min) 5 CASE 1 Time of Conc. (min) 5.00 Outflow (cfs) 0 50 ft. Overland Flow Design Year Flow 10 Area (aaes) 0.09 Ct = 0.15 Impervious Area (sq ft) 3908 L= 50 ft. 'C' Fador 0.9 n= 0.40 '208' Volume Provided 185 S= 0,020 Area " C 0.081 Tc = 2.93 min., by Equation 3-2 of Guidelines Time Time Inc. Intens. Q Devel. Vol.ln Vol.Out Storage 143 ft. Gutter flow (min) (sec) (iNhr) (cfs) (cu ft) (cu ft) (cu ft) Z1= 50.0 For Z2 5.00 300 3.16 0.26 104 0 104 Z2 = 3.5 Type B =1.0 n= 0.016 Rolled = 3.5 5 300 3.18 0.26 104 0 104 S= 0.011 10 600 2.24 0.18 127 0 127 15 900 1.77 0.14 144 0 144 d= 0.089 ft. 20 1200 1.45 0,12 153 0 153 25 1500 1.21 0.10 157 0 157 A R Q Tc Tc total I Qc 30 1800 1.04 0.06 160 0 160 35 2100 0.91 0.07 162 0 162 0.21 0.04 0.26 1.95 5.00 3.18 0.26 40 2400 0.82 0.07 166 0 166 45 2700 0.74 0.06 168 0 168 Qpeak for Case 1= 0.26 cfs 50 3000 0.68 0.06 171 0 171 55 3300 0.64 0.05 176 0 176 60 3600 0.61 0.05 183 0 183 CASE 2 65 3900 0.60 0.05 194 0 194 70 4200 0.58 0.05 202 0 202 Case 2 assumes a Time of Concentratian less than 5 minutes so that the 75 4500 0.56 0.05 209 0 209 peak flow =.90(3.18)(Imp. Area) = 0.26 cfs 80 4800 0.53 0.04 210 0 210 85 5100 0.52 0.04 219 0 219 90 5400 0.50 0.04 223 0 223 So, lhe Peak flow for the Basin is the greater of the two flows, 95 5700 0.49 0.04 230 0 230 0.26 cfs 100 6000 0.48 0.04 237 0 237 208' DRAINAGE POND CALCULATIONS Required'208' Storage Volume = Impervious Area x.5 in ! 12 inlft 163 cu ft 208' Storage Volume Pravided 185 a+ ft DRYWELL REQUIREMENTS -10 YEAR DESIGN STOR Maximum Storage Required by Bowstring 219 cu ft Number and Type of Drywells Required ERR Single ERR Double BOWSTRING METHOD PROJECT: Riven+ralk 9th Addition PEAK FLOW CALCULATION PROJECT Riverwalk 9th Addition DETENTION BASIN DESIGN BASIN: Combined HI 6 JK BASIN: Combined HI 6 JK 10-Year Design Storm DESIGNER: S. Murphy Tot. Area 1.38 Aaes DATE: 09116 Imp. Area 11470 SF C = 0.29 Time Inaement (min) 5 CASE t Time of Conc. (min) 5.83 Outflow (cfs) i 50 ft. Overland Flow Design Year Flow 10 Area (acres) 1.38 Ct = 0.15 Impervious Area (sq ft) 11470 L= 50 ft. 'C' Factor 0.29 n= 0.40 '208' Volume Provided 505.5 S= 0.020 Area' C 0.400 Tc = 2.93 min., by Equa6on 3-2 of Guidelines Time Time Inc. Intens. Q Devel. Vol.ln Vol.Out Storage 311 ft. Gutter flow (min) (sec) (iNhr) (cfs) (cu ft) (cu ft) (cu ft) Z1= 50.0 For Z2 5.83 350 2.95 1.18 552 350 203 Z2 = 3.5 Type B =1.0 n= 0.016 Rolled = 3.5 5 300 3.18 1.27 512 300 212 S= 0.011 10 600 2.24 0.90 644 600 44 15 900 1.77 0.71 722 900 -178 d= 0.157 ft. 20 1200 1.45 0.58 765 1200 435 25 1500 1.21 0.48 784 1500 -716 A R Q Tc Tc total I Qc 30 1800 1.04 0.42 799 1800 -1001 35 2100 0.91 0.36 808 2100 -1292 0.66 0.08 1.18 2.90 5.83 2.95 1.18 40 2400 0.82 0.33 827 2400 -1573 45 2700 0.74 0.30 835 2700 -1865 Qpeak for Case 1= 1.18 cfs 50 3000 0.68 0.27 849 3000 -2151 55 3300 0.64 0.26 876 3300 -2424 60 3600 0.61 0.24 908 3600 -2692 CASE 2 65 3900 0.60 0.24 965 3900 -2935 70 4200 0.58 0.23 1002 4200 -3198 Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0,56 0.22 1035 4500 -3465 peak flow =.90(3.18)(Imp. Area) = 0.75 cfs 80 4800 0.53 0.21 1043 4800 -3757 65 5100 0.52 0.21 1086 5100 -4014 90 5400 0.50 0.20 1104 5400 -4296 So, the Peak flow for the Basin is the greater of the two flows, 95 5700 0.49 0.20 1141 5700 -4559 1 18 cfs 100 6000 0.48 0,19 1175 6000 -4825 , 208' DRAINAGE POND CALCULATIONS Required '208' Slorage Volume ,r, = Impervious Area x.5 in ! 12 iNft 478 cu ft 206' Starage Volume Provided 505.5 cu ft DRYWELL REQUIREMENTS -10 YEAR DESIGN STORM Maximum Storage Required by Bowstring 212 cu ft Number and Type of Drywells Required 0 Single 1 Double BOWSTRING METHOD PROJECT: Riverwalk 9th Addition PEAK FLOW CALCULATION PROJECT Riverwalk 9th Addition DETENTION BASIN DESIGN BASIN: Predeveloped L BASIN; Predeveloped L 10-Year Design Storm DESIGNER; S. Murphy Tot. Area 0.76 Acres DATE: 09118 Imp, Area 0 SF C = 0.30 Time Inaement (min) 5 CASE 1 Time of Conc. (min) 14.78 Outflow (cfs) 0 470 ft. Overiand Flow Design Year Flow 10 Area (acres) 0.76 Ct = 0.15 Impervious Area (sq ft) 0 L= 470 ft. 'C' Facior 0.3 n = 0.40 '208' Volume Provided S= 0.008 Area' C 0228 Tc = 14.78 min., by Equation 3-2 of Guidelines Time Time Inc. Intens. Q Devel. Vol.ln Vol.Qut Storage 0 ft. Gutter flow (min) (sec) (iNhr) (cfs) (cu ft) (cu ft) (cu ft) Z1= 50.0 For Z2 14.78 887 1.80 0.41 486 0 486 Z2 = 3.5 Type 8 =1.0 n= 0.016 Rolled = 3.5 5 300 3.18 0.73 291 0 291 S= 0.005 10 600 2.24 0.51 411 0 411 15 900 1.77 0.40 485 0 485 d= 0.122 ft. 20 1200 1.45 0.33 496 0 496 25 1500 121 0.28 497 0 497 A R Q Tc Tc total I Qc 30 1640 1.04 0.24 498 0 498 35 2100 0.91 0.21 498 0 498 0.40 0.06 0.41 0.00 14.78 1.80 0.41 40 2400 0.82 0.19 505 0 505 45 2700 0.74 0.17 506 0 506 Qpeak for Case 1= 0.41 cis 50 3000 0.68 0.16 512 0 512 55 3300 0.64 0.15 526 0 526 60 3600 0.61 0.14 543 0 543 CASE 2 65 3900 0.60 0.14 575 0 575 70 4200 0.58 0.13 595 0 595 Case 2 assumes a Time of Concentration less than 5 minutes so that Ihe 75 4540 0.56 0.13 613 0 613 peak flow =.90(3.18)(Imp. Area) = 0.00 cfs 80 4800 0.53 0.12 616 0 616 85 5100 0.52 0.12 640 0 640 90 5400 0.50 0.11 650 0 654 So, the Peak flow for the Basin is the greafer of the two flows, 95 5100 0.49 0.11 670 0 670 0.41 cfs 100 6000 0.48 0,11 690 0 690 208' DRAINAGE POND CALCULATIONS Required'208' Storage Volume = Impervious Area x.5 in 112 inlfl 0 cu ft 208' Storage Volume Provided cu ft DRYWELL REQUIREMENTS -10 YEAR DESIGN STORM Maximum Storage Required by Bowstring 640 cu ft Number and Type of Drywells Required 0 Single ERR Double B(}WSTRING METH4D F'ROJECT: Riverwalk 9Eh Addfiqn PEAK FLOW CRLCIJLATIC}N PRC?JEGT Riverwalk 9kh AddiEion bETENTION BASIN DESIGN BASIN: Qeveloped L 6,4SIN: Developed L 10-Y20f De51gPl St41'Rl DESIGNER: 5 Murphy Tot, Area 6.76 Acres DATE: 09l18 lmp. Area D SF C- D.15 Time incremenl (min) 5 CASE 1 Time raf Conc. (min) 14.78 Outflow (cfs) 0 470 it. Overland Flaw Design Year Flow 10 Area (acres) 016 Ct = 0,15 Imperviaus Area (sq ft) fl L = 470 ft. 'C' Factnr 0,15 n ~ 0.44 '208' Valume Prauided S= 0,408 Area e C 0.114 Tc ~ 14.78 min., by Equation 3-2 of Guidelines Tirne Time Ine. In#ens. Q DeveL VaOJn Vol.Dut Storage 0ft, Gutter flow (min) (sec) (iNhr) f cfsy f cu ft1 {cu R) itai fl} Z1= 50.0 For Z2 14.78 887 1.80 0,20 243 4 243 Z2 = 3.5 Type B =1.0 n= OM6 Rolled = 3,5 5 300 3.18 0.36 145 0 146 s= 0.005 10 600 2.24 0.26 205 a 205 15 900 1.77 0,20 242 tl 242 d= 4.093 ff. 20 1200 1.45 0.17 248 4 248 25 1500 1.21 0.14 248 0 248 A R a Tc Tctotal I Qc 34 1840 1.G4 0,12 249 0 249 =a==-==- ==a= 35 2100 4.91 0.10 249 0 249 0.23 0.05 0.20 0.00 14,78 1.80 024 40 2400 a.82 4,09 253 0 253 45 2700 0.74 0.08 253 0 253 Qpeak for Case 1- 0_20 cfs 50 3000 0.68 0.08 266 0 256 55 3300 O.fi4 0.07 253 0 263 60 3600 O.61 0,07 279 d 271 CRSE 2 65 3900 0.60 0.07 287 0 287 lD 4200 0.58 0A7 298 0 298 Case 2 assurnes a Tirne of Concentratinn less than 5 minutes sa that ¢he 75 4500 0.56 0.06 307 Q 307 peak flnw =.90(3.18)(Imp. Area) = 4,00 cfs 80 4800 0.53 OAfi 308 0 308 85 5100 0.52 0.06 320 o 320 90 5400 0.54 0.48 325 Q 325 Sa, the Peax now for !he 8asin is the grealer n(the twa flows, 95 5700 0.49 0.46 335 0 335 0.2 0 cfs 100 6000 0.48 0.05 345 0 345 208" aRAINAt3E POND CALCIJLATI{]NS Required'208' Starage VaEume = Imperviuus Area x.5 in 112 ir/ft U cu ft 208' Slarage Volume Pravided cu ft aRYWELL REraUIREMENTS-1aYEAR pESIGN SroRM Maximum Starage Required by Bowstring 320 cu ft , ~r ' Nurnber and 7ype of Drywells Requ~red 0 Single ERR Qouble BOWSTRING METHOD PROJECT: Riveiwalk 9th Addifion PEAK FLOW CALCULATION PROJECT Riverwalk 9ih Addftion DETENTION BASIN DESIGN BASIN: Predeveloped M BASIN: Predeveloped M 10-Year Design Storm DESIGNER: S. Murphy Tot. Area 0.16 Acres DATE: 09118 Imp. Area 0 SF C = 0.30 Time Increment (min) 5 CASE 1 Time of Conc. (min) 5.00 Outflow (cfs) 0 80 ft. Overland Flow Design Year Flow 10 Area (acres) 0.16 Ct = 0.15 Impervious Area (sq ft) 0 L= 60 ft. 'C' Factor 0.3 n = 0.40 '208' Volume Provided S= 0.010 Area ' C 0.048 Tc = 4.78 min., by Equation 3-2 of Guidelines Time Time Inc. Intens. Q Devel. Vol.ln Vol.Out Storage 0 ft. Gutter flow (min) (sec) (in/hr) (cfs) (cu ft) (cu ft) (cu ft) - Z1 = 50.0 For Z2 5.00 300 3.18 0.15 61 0 61 Z2 = 3.5 Type B =1.0 n= 0,016 Rolled = 3.5 5 300 3.18 0.15 61 0 61 S= 0,005 10 600 2.24 0.11 75 0 75 15 900 1.71 0.08 85 0 85 d= 0,065 ft. 20 1200 1.45 0.07 91 0 91 25 1500 121 0.06 93 0 93 A R Q Tc Tc total I Qc 30 1800 1.04 0.05 95 0 95 35 2100 0.91 0.04 96 0 96 0.19 0.04 0.15 0.00 5.00 3.18 0.15 40 2400 0.82 0.04 98 0 98 45 2700 0.74 0.04 100 0 100 Qpeak for Case 1= 0.15 cfs 50 3000 0.68 0.03 101 0 101 55 3300 0.64 0.03 105 0 105 60 3600 0.61 0.03 108 0 108 CASE 2 65 3900 0.60 0.03 115 0 115 70 4200 0.58 0.03 120 0 120 Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.56 0.03 124 0 124 peak flow =.90(3.18)(Imp. Area) = 0.00 cfs 80 4800 0.53 0.03 125 0 125 85 5100 0.52 0.02 130 0 130 90 5400 0.50 0.02 132 0 132 So, the Peak 8ow for the Basin is the greater of the two flows, 95 5700 0.49 0.02 136 0 136 0.15 cfs 100 6000 0.48 0.02 141 0 141 208' DRAINAGF POND CALCULATIONS Required'208' Storage Volume = Impervious Area x.5 in ! 12 inlft 0 cu ft 208' Storage Volume Provided cu ft DRYWELL REQUIREMENTS -10 YEAR DESIGN STORM Maximum Storage Required by 8owstnng 130 cu ft Number and Type of Drywells Required 0 Single ERR Double BOWSTRING METHOD PROJECT: Riverwalk 9th Addition PEAK FLOW CALCULATION PROJECT Riverwalk 9th Addition DETENTION BASIN DESIGN BASIN: Developed M BASIN Developed M 10-Year Design Storm DESIGNER: S. Murphy Tot. Area 0.16 Acres DATE: 09118 Imp. Area 0 SF C = 0.15 Time Increment (min) 5 CASE 1 Time of Conc. (min) 5.00 Outflow (cfs) 0 80 ft. Overland Flow Design Year Flow 10 Area (aaes) 0.16 Ct = 0.15 Impervious Area (sq ft) 0 L= 80 ft. 'C' Factor 0.15 n = 0.40 '208' Volume Provided S= 0.010 Area' C 0.024 Tc = 4.78 min., by Equation 3-2 of Guidelines Time Time Inc. Intens. Q Devel, Vol.ln Vol.Out Staage 0 ft. Gutter flow (min) (sec) (iNhr) (cfs) (cu ft) (cu ft) (cu ft) Z1= 50.0 For Z2 5.00 300 3.18 0.08 31 0 31 Z2 = 3.5 Type B =1.0 n= 0.016 Rolled = 3.5 5 300 3.18 0.08 31 0 31 S= 0,005 10 600 2.24 0.05 38 0 38 15 900 1.77 0.04 43 0 43 d= 0,065 ft. 20 1200 1.45 0.03 45 0 45 25 1500 121 0.03 47 0 47 A R Q Tc Tc total I Qc - 30 1800 1.04 0.02 47 0 47 35 2100 0.91 0.02 48 0 48 0.11 0.03 0,08 0.00 5.00 3.18 0.08 40 2400 0.82 0.02 49 0 49 45 2700 0.74 0.02 50 0 50 Qpeak for Case 1= 0.08 cfs 50 3000 0.68 0.02 51 0 51 55 3300 0.64 0.02 52 0 52 60 3600 0.61 0.01 54 0 54 CASE 2 65 3900 0,60 0.01 58 0 58 70 4200 0.58 0.01 60 0 60 Case 2 assumes a Time of ConcenVation less than 5 minutes so lhat the 75 4500 0.56 0.01 62 0 62 peak flow =.90(3.18)(Imp. Area) = 0.00 cfs 80 4800 0.53 0.01 62 0 62 85 5100 0.52 0.01 65 0 65 90 5400 0.50 0.01 66 0 66 So, the Peak flow for the Basin is the greater of the twa flows, 95 5700 0,49 0,01 68 0 68 0.08 cfs 100 6000 0.48 0.01 70 0 70 208' DRAINAGE POND CALCULATIONS Required '208' Storage Volume = Impervious Area x.5 in ! 12 iNft 0 cu ft 208' Storage Volume Provided cu ft DRYVYELL REQUIREMENTS -10 YEAR DESIGN STORM Maximum Storage Required by Bowstring 65 cu ft Number and Type of Orywells Required 0 Single ERR Double BOWSTRING METHOD PROJECT: Riverwalk 9th Addition PEAK FLOW CALCULATION PROJECT Riverwalk 9lh Addition DETENTION BASIN DESIGN BASIN: Predeveloped N BASIN: Predeveloped N 10-Year Design Storm DESIGNER: S. Murphy Tot. Area 0.26 Acres DATE: 09N8 Imp. Area 0 SF C = 0.30 Time Incremenl(min) 5 CASE 1 Time of Conc. (min) 5.00 Outflow (cfs) 0 50 ft. Overland Flow Design Year Flow 10 Area (aaes) 0.26 Ct = 0.15 Impervious Area (sq ft) 0 L= 50 ft. 'C' Factor 0.3 n = 0.40 '208' Valume Provided S= 0.008 Area " C 0.078 Tc = 3.85 min., by Equation 3-2 of Guidelines Time Time Inc. Intens. Q Devel. Vol.ln Vol.Oul Storage 0 ft. Gutter flow (min) (sec) (iNhr) (cfs) (cu ft) (cu ft) (cu ft) Z1= 50.0 For Z2 5.00 300 3.18 0.25 100 0 100 Z2 = 3.5 Type B =1.0 n= 0.016 Rolled = 3.5 5 300 3.18 0.25 100 0 100 S= 0.005 10 600 2.24 0.17 123 0 123 15 900 1.77 0.14 138 0 138 d= 0.102 ft. 20 1200 1.45 0.11 141 0 147 25 1500 1.21 0.09 151 0 151 A R a Tc Tc total I Qc 30 1800 1.04 0.08 154 0 154 35 2100 0.91 0.07 156 0 156 0.28 4.05 0.25 0.00 5.00 3.18 0,25 40 2400 0.82 0.06 160 0 160 45 2700 0,14 0.06 162 0 162 Opeak for Case 1= 0.25 cfs 50 3000 0,68 0.05 165 0 165 55 3300 0.64 0.05 170 0 170 60 3600 0.61 0.05 176 0 176 CASE 2 65 3900 0.60 0.05 187 0 187 70 4200 0.58 0.05 195 0 195 Case 2 assumes a Time of Concentration less than 5 minules so that the 75 4500 0.56 0.04 201 0 201 peak flow =.90(318)(Imp. Area) = 0.00 cfs 80 4800 0.53 0.04 203 0 203 85 5100 0.52 0.04 211 0 211 90 5400 0.50 0.04 215 0 215 So, the Peak flow for the Basin is the greater of the two flows, 95 5700 0.49 0.04 222 0 222 0.25 cfs 100 6000 0,48 0.04 228 0 228 208' DRAINAGE POND CALCULATIONS Required '208' Storage Volume = Imperoious Area x.5 in /12 iNft 0 cu ft 208' Storage Volume Provided cu ft DRYWELL REQUIREMENTS -10 YEAR DESIGN STORM Maximum Storage Required by Bowstring 211 cu ft Number and Type of Drywells Required 0 Single ERR Double BOWSTRING METHOD PROJECT: Riverwalk 9th Addition PEAK FLOW CALCULATION PROJECT Riverwalk 9th Addition DETENTION BASIN DESIGN BASIN: Developed N BASIN: Developed N 10-Year Design Storm DESIGNER: S. Murphy Tot. Area 0.26 Aaes DATE: 09118 Imp. Area 0 SF C = 0.15 Time Inaement (min) 5 CASE 1 Time of Conc. (min) 5.00 Outflow (cfs) 0 50 ft. Overland Flow Design Year Flow 10 Area (aaes) 0.26 Ct = 0.15 Imperoious Area (sq ft) 0 L= 50 ft. 'C' Factor 0.15 n = 0.40 '208' Volume Provided S= 0,008 Area' C 0.039 Tc = 3.85 min., by Equation 3-2 of Guidelines Time Time Inc. Intens. Q Devel. Vol.ln Vol.Out Storage 0 fl. Gutter flow (min) (sec) (iNhr) (cfs) (cu fl) (cu ft) (cu ft) - - Z1= 50.0 For Z2 5.00 300 3.18 0.12 50 0 50 Z2 = 3.5 Type B =1,0 n= 0.016 Rolled = 3.5 5 300 3.18 0.12 50 0 50 S= 0,005 10 600 224 0.09 61 0 61 15 900 1.77 0.07 69 0 69 d= 0.078 ft. 20 1200 1.45 0.06 14 0 74 25 1500 1.21 0.05 76 0 76 A R Q Tc Tc total I Qc 30 1800 1.04 0.04 77 0 77 - - 35 2100 0.91 0.04 18 0 78 - 0.16 0.04 0,12 0.00 5.00 3,18 0.12 40 2400 0.82 0.03 80 0 80 45 2700 0.74 0.03 81 0 81 Qpeak for Case 1= 0.12 cfs 50 3000 0.68 0.03 82 0 82 55 3300 0.64 0.02 85 0 85 60 3600 0.61 0.02 88 0 88 CASE 2 65 3900 0.60 0.02 94 0 94 70 4200 0.58 0.02 97 0 97 Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4540 0.56 0.02 101 0 101 peak Oow =.90(3.18)(Imp. Area) = 0.00 cfs 80 4800 0.53 0.02 101 0 101 85 5100 0,52 0.02 105 0 105 90 5400 0.50 0.02 107 0 107 So, the Peak flow for the Basin is the greater of the two flows, 95 5700 0.49 0,02 111 0 111 0.12 cfs 100 6000 0.48 0.02 114 0 114 208' DRAINAGE POND CALCULATIONS Required '208' Storage Volume = Impervious Area x.5 in f 12 iNft 0 cu ft 208' Storage Volume Provided cu ft DRYWELL REQUIREMENTS -10 YEAR DESIGN STORM Maximum Storage Required by Bowstnng 105 cu ft Number and Type of Drywells Required 0 Single ERR Double BOWSTRING METHOD PROJECT: Riverwalk 9th Addition PEAK FLOW CALCULATION PROJECT Riverwalk 9lh Addition DETENTION BASIN DESIGN BASIN: Predeveloped 0 BASIN: Predeveloped 0 10-Year Design Storm DESIGNER: S. Murphy Tot. Area 0.85 Acres DATE: 09118 Imp. Area 0 SF C = 0.30 Time Increment (min) 5 CASE 1 Time of Conc. (min) 5.46 Outflow (cfs) 0 100 ft. Overiand Flow Design Year Flow 10 Area (acres) 0.85 Ct = 0.15 Impervious Area (sq ft) 0 L= 100 ft. 'C' Factor 0.3 n = 0.40 '208' Volume Provided S= 0.010 Area ' C 0.255 Tc = 5.46 min., by Equa6on 3-2 of Guidelines Time Time Inc. Intens. Q Devel. Vol.ln Vol.Out Storage 0 ft. Gutter flow (min) (sec) (iNhr) (cfs) (cu ft) (cu ft) (cu fl) - - Z1= 50.0 For Z2 5,46 328 3.06 0.78 343 0 343 Z2 = 3.5 Type B =1,0 n= 0.016 Rolled = 3.5 5 300 3.18 0.81 326 0 326 S= 0.005 10 600 2.24 0.57 406 0 406 15 900 1.77 0.45 457 0 457 d= 0.156 ft. 20 1200 1.45 0.37 485 0 485 25 1500 1.21 0.31 497 0 497 A R Q Tc Tc total I Qc 30 1800 1.04 0.27 507 0 507 - = 35 2100 0.91 0.23 513 0 513 0.65 0.08 0.76 0.00 5.46 3.06 0.78 40 2400 0.82 0.21 525 0 525 45 2700 0.74 0.19 531 0 531 Qpeak for Case 1= 0.78 cfs 50 3000 0.68 0.17 540 0 540 55 3300 0.64 0.16 557 0 557 60 3600 0.61 0.16 577 0 577 CASE 2 65 3900 0.60 0.15 614 0 614 70 4200 0.58 0,15 638 0 638 Case 2 assumes a Time of ConcenVation less than 5 minutes so that the 75 4500 0.56 0,14 659 0 659 peak flow =.90(3.18)(Imp. Area) = 0.00 cfs 80 4800 0.53 0,14 664 0 664 85 5100 0.52 0.13 691 0 691 90 5400 0.50 0.13 703 0 703 So, the Peak flow for the Basin is the greater of the two flows, 95 5700 0.49 0.12 726 0 726 0.78 cfs 100 6000 0.48 0.12 748 0 748 208' DRAINAGE POND CALCULATIONS Required'208' Storage Volume = Imperoious Area x.5 in I 12 iNft 0 cu ft 208' Storage Volume Provided cu fl DRYWELL REQUIREMENTS -10 YEAR DESIGN STORM Maximum Storage Required by Bowstring 691 cu ft Number and Type of Drywells Required 0 Single ERR Double BOWSTRING METHOD PROJECT: Rivenvalk 9th Addition PEAK FLOW CALCULATION PROJECT Riverwalk 9th Addition DETENTION BASIN OESIGN BASIN: Developed 0 BASIN: Developed 0 10-Year Design Stortn DESIGNER: S. Murphy Tot. Area 0.85 Acres DATE: 09118 Imp. Area 0 SF C = 0.15 Time Increment (min) 5 CASE 1 Time of Conc. (min) 5.46 Outflow (cfs) 0 100 ft. Overland Flow Design Year Flow 10 Area (acres) 0.85 Ct = 0.15 Impervious Area (sq ft) 0 L= 100 ft. 'C' Factor 0.15 n = 0.40 '208' Volume Provided S= 0.010 Area' C 0,128 Tc = 5.46 min., by Equation 3-2 of Guidelines Time Time Inc. Intens. Q Devel. Vol,ln Vol.Out Storage 0 ft. Gutter flow (min) (sec) (iNhr) (cfs) (cu ft) (cu ft) (cu ft) Z1 = 50.0 For Z2 5.46 328 3.06 0.39 171 0 171 Z2 = 3.5 Type B =1.0 n= 0.016 Rolled = 3.5 5 300 3.18 0.41 1630 163 S= 0.005 10 600 2.24 0.29 203 0 203 15 900 1.77 0.23 228 0 228 d= 0.120 ft. 20 1200 1.45 0.18 242 0 242 25 1500 1.21 0.15 249 0 249 A R Q Tc Tc total I Qc 30 1800 1.04 0.13 253 0 253 35 2100 0.91 0.12 257 0 257 0.39 0.06 0.39 0.00 5.46 3.06 0.39 40 2400 0.82 0.10 263 0 263 45 2700 0.74 0.09 265 0 265 Qpeak for Case 1= 0.39 cfs 50 3000 0.68 0.09 270 0 270 55 3300 0.64 0.08 278 0 278 60 3600 0.61 0.08 289 0 289 CASE 2 65 3900 0.60 0.08 307 0 307 70 4200 0.58 0.07 319 0 319 Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4504 0.56 0.07 329 0 329 peak flow =.90(3.18)(Imp. Area) = 0.00 cfs 60 4800 0.53 0.07 332 0 332 85 5100 0.52 0.07 346 0 346 90 5400 0.50 0,06 351 0 351 So, the Peak flow for the Basin is the greater of the two flows, 95 5700 0.49 0.06 363 0 363 0.39 cfs 100 6000 0.48 0.06 374 0 374 208' DRAINAGE POND CALCULATIONS Required'208' Storage Volume = Impervious Area x.5 in 112 inlft 0 cu ft 208' Storage Volume Provided cu ft DRYWELL REQUIREMENTS • 10 YEAR DESIGN STORM Maximum Storage Required by Bowstring 346 cu ft Number and Type of Drywells Required 0 Single ERR Double BOWSTRING METHOD PROJECT: Riverwalk 9th Addition PEAK FLOW CALCULATION PROJECT Riverwalk 9th Addition DETENTION BASIN DESIGN BASIN: P BASIN: P 10-Year Design Storm DESIGNER: S. Murphy Tot. Area 0.31 Acres DATE: 03/23 Imp. Area 6502 SF C = 0.59 Time Increment (min) 5 CASE 1 Time of Conc. (min) 5.00 Outflow (cfs) 0.3 45 ft. Overland Flow Design Year Flow 10 Area (acres) 0.31 Ct = 0.15 Impenrious Area (sq ft) 6502 L= 45 ft. 'C Factor 0.59 n= 0.16 '208' Volume Pravided 271 S= 0.020 Area + C 0.183 Tc = 1.59 min., by Equation 3-2 of Guidelines Time Time Inc. Intens, Q Devel. Vol.ln Vol.Out Storage 120 ft. Gutter flow (min) (sec) (inlhr) (cfs) (cu ft) (cu ft) (cu ft) Z1= 50.0 For Z2 5.00 300 3.18 0.58 234 90 144 Z2 = 1 Type B =1.0 n= 0.016 Rolled = 3.5 5 300 3.18 0.58 234 90 144 S= 0.008 10 600 2.24 0.41 288 180 108 15 900 1.77 0.32 324 270 54 d= 0.130 ft. 20 1200 1.45 0,27 345 360 -15 25 1500 1.21 0.22 355 450 -95 A R Q Tc Tc total I Qc 30 1800 1.04 0.19 362 540 -178 35 2100 0.91 0.17 366 630 -264 0.43 0.06 0.58 , 1.49 5.00 3.18 0.58 40 2400 0.82 0.15 375 720 -345 45 2700 0.74 0.14 379 810 -431 Qpeak for Case 1= 0,58 cfs 50 3000 0.68 0.12 386 900 -514 55 3300 0.64 0.12 398 990 -592 60 3600 0.61 0.11 413 1080 -667 CASE 2 65 3900 0.60 0.11 439 1170 -731 10 4200 0.58 0.11 456 1260 -804 Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.56 0.10 471 1350 -879 peak flow =.90(3.18)(Imp. Area) = 0.43 cfs 80 4840 0.53 0.10 475 1440 -965 85 5100 0.52 0.10 495 1530 -1035 90 5400 0.50 0.09 503 1620 -1117 So, the Peak flow for the Basin is the greater of the two flows, 95 5700 0,49 0.09 520 1110 •1190 0.58 cfs 100 6000 0.48 0.09 536 1800 -1264 208' DRAINAGE POND CALCULATIONS Required'208' Storage Volume = Impervious Area x.5 in I 12 inlft 271 cu R 208' Storage Volume Provided 271 cu ft DRYWELL REQUIREMENTS -10 YEAR DESIGN STORM Maximum Slorage Required by Bowstring 144 cu ft Number and Type of Drywells Required 1 Single 0 Double 50-year STORM BOWSTRING METHOD PROJECT: Riverwalk 9th Addition PEAK FLOW CALCULATION PROJECT Rivenvalk 9th Addition DETENTION BASIN DESIGN BASIN: A BASIN: A DESIGNER: S. Murphy Tot. Area 1.12 Aaes DATE: 09121 Imp, Area 10748 SF C = 0.32 Time Inc,rement (min) 5 CASE 1 Time of Conc, (min) 6.81 Outflow (cfs) 1 120 ft. Overiand Flow Design Year Flow 50 Area (acxes) 1.12 Ct = 0.15 Impervious Area (sq ft) 10748 L= 120 ft. 'C' Factor 0.32 n= 0.40 50-year Volume Provided 573.5 S= 0.020 Area' C 0.358 Tc = 4.95 min., by Equafion 3-2 of Guidelines Time Time Inc. Intens. Q Devel. Vol.ln Vol.Out Staage 202 ft. Gutter flow (min) (sec) (iNhr) (cfa) (cu ft) (cu ft) (cu ft) Z1= 50.0 6.81 409 3.95 1.42 776 409 368 72 = 3.5 n= 0.016 5 300 4.58 1.64 660 300 360 S= 0.010 10 600 3.20 1.15 847 600 247 15 900 2.45 0.88 912 900 12 d= 0.172 ft. 20 1200 1.95 0.70 936 1200 -264 25 1500 1.62 0.58 952 1500 -548 A R Q Tc Tc total I Qc 30 1800 1.56 0.56 1084 1800 -716 35 2100 1.28 0.46 1027 2100 -1073 0.79 0.09 1.42 1.86 6.81 3.95 1.42 40 2400 1.19 0.42 1078 2400 -1322 45 2700 1.08 0.39 1099 2700 -1601 Qpeak for Case 1= 1.42 cfs 50 3000 0.99 0.35 1114 3000 -1886 55 3300 0.92 0.33 1134 3300 -2166 60 3600 0.87 0.31 1166 3600 -2434 CASE 2 65 3900 0.82 0.29 1187 3900 -2713 70 4200 0.80 0.29 1244 4200 -2956 Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.77 0.28 1280 4500 -3220 peak flow =.90(4.58)(Imp. Area) = 1.02 cfs 80 4800 0.75 0.27 1328 4800 -3472 85 5100 0.72 0.26 1352 5100 -3748 90 5400 0.71 0.25 1409 5400 -3991 So, the Peak flaw for the Basin is the greater of the two flows, 95 5700 0.69 0,25 1444 5700 -4256 1.42 cfs 100 6000 0.67 0.24 1474 6000 4526 208' DRAINAGE POND CALCULATIONS Required'208' Storage Volume = Impervious Area x.5 in 112 inlft 448 cu ft '208' Volume Provided 573.5 cu ft DRYWELL REQUIREMENTS - 50 YEAR DESIGN STORM Maximum Slorage Required by Bowstring 368 cu ft Number and Type of Drywells Required 0 Single 1 Double INLAND PACIFIC ENGINEERING 50-year STORM BOWSTRING METHOD PROJECT: Riverwalk 9th Addition PEAK FLOW CALCULATION PROJECT Riverwalk 9th Addition DETENTION BASIN DESIGN BASIN: B BASIN: B DESIGNER: S. Murqhy Tot. Area 0.39 Acres DATE: 09115 Imp.Area 4598 SF C = 0,36 Time Increment (min) 5 CASE 1 Time of Conc. (min) 6.30 Outflow (cfs) 0.3 65 fl, Overland Flow Design Year Flow 50 Area (aaes) 0.39 C1= 0.15 Impenrious Area (sq ft) 4598 L= 65 fl. 'C' Fador 0.36 n= 0.40 50-year Volume Provided 211 S= 0.020 Area' C 0.140 Tc = 3.43 min., by Equation 3-2 of Guidelines Time Time Inc. Intens. Q Devel. Vol.ln Vol.Out Storage 249 fl. Gutter flow (min) (sec) (iNhr) (cfs) (cu ft) (cu fl) (cu ft) Z1= 50.0 6.30 378 4.13 0.58 294 113 180 Z2 = 3.5 n= 0.016 5 300 4.58 0.64 258 90 168 S= 0.010 10 600 3.20 0.45 327 180 147 15 904 2,45 0.34 354 270 84 d= 0.123 ft. 20 1200 1.95 0.27 364 360 4 25 1500 1.62 0.23 370 450 -80 A R Q Tc Tc total I Qc 30 1800 1.56 0.22 422 540 -118 - 35 2100 1.28 0.18 400 630 -230 - 0.40 0.06 0.58 2.87 6.30 4.13 0.58 40 2400 1.19 0.17 421 720 -299 45 2700 1,08 0.15 429 810 -381 Qpeak for Case 1= 0.58 cfs 50 3000 0.99 0.14 435 900 -465 55 3300 0.92 0.13 443 990 -547 60 3600 0.87 0,12 455 1080 -625 CASE 2 65 3900 0.82 0.12 464 1170 -706 70 4200 0.80 0.11 486 1260 -774 Case 2 assumes a Time of Concentration less than 5 minutes so that lhe 75 4500 0.77 0.11 500 1350 -850 peak flow =.90(4.58)(Imp. Area) = 0.44 cfs 80 4800 0.75 0.11 519 1440 -921 85 5100 0.72 0.10 529 1530 -1001 90 5400 0.71 0.10 551 1620 -1069 So, the Peak flow for the Basin is the greater of lhe two flows, 95 5700 0.69 0.10 565 1710 -1145 0.58 cfs 100 6000 0,67 0.09 576 1800 -1224 208' DRAINAGE PQND CALCULATIONS Required'208' Storage Volume = Impervious Area x.5 in I 12 iNft 192 cu ft 50 year Volume Provided 187.5 cu ft DRYWELL REQUIREMENTS - 50 YEAR DESIGN STORM Maximum Storage Required by Bowstring 180 cu fl R Number and Type of Drywells Required 1 Single 0 Double INLAND PACIFIC ENGINEERING 50-year STORM BOWSTRING METHOD PROJECT: Riverwalk 9th Addition PEAK FLOW CALCULATION PROJECT Riverwalk 9th Addition DETENTION BASIN OESIGN BASIN: C BASIN C DESIGNER: S. Murphy Tot. Area 1.48 Acres DATE: 09l15 Imp. Area 11380 SF C = 0,28 Time Increment (min) 5 CASE 1 Time of Conc, (min) 6.51 Outflow (cfs) 1 50 ft. Overland Flow Design Year Flow 50 Area (aaes) 1.48 Ct = 0.15 Impervious Area (sq ft) 11380 L= 50 ft. 'C' Faclor 0.28 n= 0.40 50-year Volume Provided 496 S= 0.020 Area ' C 0.414 Tc = 2.93 min., by Equation 3-2 of Guidelines Time Time Inc. Intens. Q Devel. Vol.ln Vol.Out Starage 447 ft. Gutter flow (min) (sec) (inmr) (cfs) (cu ft) (cu fl) (cu ft) - - Z1= 50.0 6.51 391 4.06 1.68 680 391 490 Z2 = 3.5 n= 0.016 5 300 4.58 1.90 763 300 463 S= 0.013 10 600 3.20 1.33 972 600 372 15 900 2.45 1.02 1049 900 149 d= 0.174 R. 20 1200 1.95 0.81 1077 1200 -123 25 1500 1.62 0.67 1096 1500 -404 A R Q Tc Tc lotal I Qc 30 1800 1.56 0.65 1249 1800 -551 35 2100 1.28 0.53 1184 2100 -916 - - - - 0.81 0.09 1.68 3.58 6.51 4.06 1.68 40 2400 1.19 0.49 1244 2400 -1156 45 2700 1.08 0.45 1268 2700 -1432 Qpeak for Case 1= 1.68 cfs 50 3040 0.99 0.41 1285 3000 -1715 55 3300 0.92 0.38 1309 3300 -1991 60 3600 0.87 0.36 1346 3600 -2254 CASE 2 65 3900 0.82 0.34 1370 3900 -2530 70 4200 0,80 0.33 1436 4200 -2764 Case 2 assumes a Time of Concentration less than 5 minutes so thal the 75 4500 0.77 0.32 1478 4500 -3022 peak flow =.90(4.58)(Imp. Area) = 1.08 cfs 80 4800 0.75 0,31 1533 4600 -3267 85 5100 0.72 0.30 1561 5100 -3539 90 5400 0.71 0.29 1628 5400 -3772 So, the Peak flow for the Basin is the greater of the two flows, 95 5700 0.69 0.29 1668 5700 -4032 1.68 cfs 100 6000 0.67 0.28 1703 6000 -4297 208' DRAINAGE POND CALCULATIONS Required'208' Storage Volume = Impervious Area x.5 in 112 iNft 474 cu fl 50 year Volume Provided 496 cu fl DRYWELL REQUIREMENTS - 50 YEAR DESIGN STOR Maximum Storage Required by Bowstring 490 cu ft Number and Type of Drywells Required 0 Single ~ 1 Double INLAND PACIFIC ENGINEERING 50-year STORM BOWSTRING METHOD PROJECT: Riverwalk 9th AddKion PEAK FLOW CALCUlATION PROJECT Riverwalk 9th Addition DETENTION BASIN DESIGN BASIN: D BASIN: D DESIGNER: S. Murphy Tot. Area 0.75 Acres DATE: 09115 Imp. Area 6174 SF C = 0,29 Time Increment (min) 5 CASE 1 Time of Conc. (min) 6,70 Outflow (cfs) 0,3 120 ft. Overland Flow Design Year Flow 50 Area (aaes) 0.75 Ct = 0.15 Impervious Area (sq ft) 6174 L= 120 ft. 'C' Factor 0,29 n= 0.40 50-year Volume Provided 262 S= 0.020 Area' C 0.217 Tc = 4.95 min., by Equation 3-2 of Guidelines Time Time Inc. Iniens. Q Devel. Vol.ln Val.Out Storage 200 ft. Gutter flow (min) (sec) (inlf►r) (cfs) (cu ft) (cu R) (cu ft) Z1= 50.0 ' 6.70 402 3.99 0.87 468 121 341 Z2 = 3.5 n= 0.016 5 300 4.58 1.00 400 90 310 S= 0.016 10 600 3.20 0.70 513 180 333 15 900 2.45 0.53 552 270 282 d= 0.131 ft. 20 1200 1.95 0.42 567 360 201 25 1500 1.62 0.35 577 450 127 A R Q Tc Tc total I Qc 30 1840 1.56 0.34 657 540 117 - - 35 2100 128 0.28 623 630 -7 0.46 0.07 0.87 1.75 6.70 3.99 0.87 40 2400 1.19 0.26 654 720 -66 45 2700 1.08 0.23 666 810 -144 Qpeak for Case 1= 0.87 cfs 50 3000 0.99 0.22 675 900 -225 55 3300 0.92 0.20 688 990 -302 60 3600 0.87 0.19 707 1080 -373 CASE 2 65 3900 0.82 0.18. 720 1170 -450 70 4200 0.80 0.17 755 1260 -505 Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.77 0.17 777 1350 -573 peak flow =.90(4.58)(Imp. Area) = 0.58 efs 80 4800 0.75 0.16 805 1440 -635 85 5100 0.72 0.16 820 1530 -710 90 5400 0.71 0.15 855 1620 •765 So, the Peak flow for the Basin is the greater of the two Bows, 95 5700 0.69 0.15 876 1710 -834 0.87 cfs 100 6000 0,67 0.15 894 1800 -906 208' DRAINAGE POND CALCULATIONS Required'208' Storage Volume = Impervious Area x.5 in / 12 iNft 257 cu ft 50 year Volume Provided 262 cu ft DRYWELL REQUIREMENTS - 50 YEAR DESIGN STORM Maximum Storage Required by Bowstring 347 cu ft Number and Type of Drywells Required 1 Single 0 Double INLANO PACIFIC ENGINEERING 50-year STORM BOWSTRING METHOD PROJECT: Riverwalk 9th Addition PEAK FLOW CALCULATION PROJECT Riverwalk 9th Addition DETENTION BASIN DESIGN BASIN: E BASIN: E DESIGNER: S. Murphy Tot. Area 0.64 Acres DATE: 03/23 Imp. Area 11277 SF C = 0.45 Time Increment (min) 5 CASE 1 Time of Conc. (min) 5.00 Outflow (cfs) 0.3 17 ft. Overland Flow Design Year Flow 50 Area (acres) 0.64 Ct = 0.15 Impervious Area (sq ft) 11277 L= 17 ft. 'C' Factor 0.45 n= 0.02 50-year Volume Provided 487.5 S= 0.020 Area ' C 0.288 Tc = 0.25 min., by Equation 3-2 of Guidelines Time Time Inc. Intens. Q Devel. Vol.ln Vol.Out' Storage 135 ft. Gutter flow (min) (sec) (in/hr) (cfs) (cu ft) (cu ft) (cu ft) Z1 = 50.0 5,00 300 4.58 1.32 530 90 440 Z2 = 3.5 n= 0,016 5 300 4.56 1.32 530 90 440 S= 0.010 10 600 3.20 0.92 647 180 467 15 940 2.45 0.71 707 270 437 d= 0.167 ft. 20 1200 1.95 0.56 731 360 371 25 1500 1.62 0.47 747 450 297 A R Q Tc Tc total I Qc 30 1800 1.56 0.45 855 540 315 - - - 35 2100 1,28 0.31 812 630 182 0.75 0.08 1.32 1.27 5.00 4.58 1.32 40 2400 1.19 0.34 854 720 134 45 2700 1.08 0.31 872 810 62 Qpeak for Case 1= 1.32 cfs 50 3000 0.99 0.29 884 900 -16 55 3300 0.92 0.26 901 990 -89 60 3600 0.87 0.25 928 1080 -152 CASE 2 65 3900 0.82 0,24 945 1170 -225 70 4200 0.80 0.23 991 1260 -269 Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0,77 0.22 1021 1350 -329 peak flow =.90(4.58)(Imp. Area) = 1.07 cfs 80 4800 0.75 0.22 1059 1440 -381 85 5100 0.72 0.21 1079 1530 -451 90 5400 0.71 0.20 1125 1620 -495 So, the Peak flow for the Basin is the greater of the two flows, 95 5100 0.69 0.20 1153 1710 -557 1.32 cfs 100 6000 0.67 0.19 1177 1800 -623 208' ORAINAGE POND CALCULATIONS Required'208' Storage Volume = Impervious Area x.5 in / 12 inlft 470 cu ft 50 year Volume Provided 487.5 cu ft DRYWELL REQUIREMENTS - 54 YEAR DESIGN STORM Maximum Storage Required by Bowstring 467 cu ft Number and Type of Drywells Required 1 Single 0 Double INLAND PACIFIC ENGINEERING 50-year STORM BOWSTRING METHOD PROJECT: Riverwalk 9th Addition PEAK FLOW CALCULATION PROJECT Riverwalk 9th Addition DETENTION BASIN DESIGN BASIN: F BASIN; F DESIGNER: S. Murphy Tot. Area 0.57 Acres DATE: 09115 Imp. Area 5161 SF C = 0.31 Time Increment (min) 5 CASE 1 Time of Conc. (min) 5.83 Outflow (cfs) 0.3 100 fl. Overland Flow Design Year Flow 50 Area (acres) 0.57 Ct = 0.15 Impervious Area (sq ft) 5161 L= 100 ft. 'C' Factor 0.31 n= 0.40 50-year Volume Provided 223.5 S= 0,020 Area • C 0.177 Tc = 4.44 min., by Equation 3-2 af Guidelines Time Time Inc. Intens. Q Devel. Vol,in Vol.Out Storage 146 ft. Gutter flow (min) (sec) (iNhr) (cfs) (cu ft) (cu fl) (cu ft) Z1= 50.0 5.83 350 4.29 0.76 356 105 251 Z2 = 3.5 n= 0.016 5 300 4.58 0.81 325 90 235 S= 0.014 10 600 3.20 0.57 406 180 226 15 900 2.45 0.43 441 270 171 d= 0.127 fl. 20 1200 1.95 0.34 454 360 94 25 1500 1.62 0.29 463 450 13 A R Q Tc Tc toial I Qc 30 1800 1.56 0.28 529 540 -11 - 35 2100 1.28 0.23 502 630 -128 0.43 0.06 0.76 1.39 5.83 4.29 0.76 40 2400 1.19 0.21 527 720 -193 45 2700 1.08 0.19 538 810 -272 Qpeak for Case 1= 0.76 cfs 50 3000 0.99 0.17 546 900 -354 55 3300 0.92 0.16 556 990 -434 60 3604 0.87 0.15 572 1080 -508 CASE 2 65 3900 0.82 0.14 582 1170 -588 70 4200 0.80 0.14 611 1260 -649 Case 2 assumes a Time of Concentration less than 5 minuies so that the 75 4500 0.77 0.14 628 1350 -722 peak flow =.90(4.58)(Imp. Area) = 0.49 cfs 80 4800 0.75 0.13 652 1440 -788 85 5100 0.72 0.13 664 1530 -866 90 5400 0.71 0.13 692 1620 -928 So, lhe Peak flow for the Basin is the greater of the two flows, 95 5700 0.69 0.12 709 1710 -1001 0.76 cfs 100 6000 0.67 0.12 724 1800 -1076 208'nRaiNAGE POND CALCULATIONS Required'206' Storage Volume ~ = Impervious Area x.5 in I 12 inlft 215 cu ft 50 year Volume Provided 223.5 cu fl DRYWELL REQUIREMENTS • 50 YEAR DESIGN STORM Maximum Storage Required by Bowstring 251 cu ft Number and Type of Drywells Required 1 Single 0 Double IN;AND PACIFIC ENGINEERING 50-year STORM BOWSTRING METHOD PROJECT: Riverwalk 9th Addition PEAK FLOW CALCULATION PROJECT Riverwalk 9th Addition DETENTION BASIN DESIGN BASIN: G BASIN: G OESIGNER: S. Murphy Tot. Area 0.63 Acres DATE: 09115 Imp. Area 6092 SF C = 0.32 Time Inaement (min) 5 CASE 1 Time of Conc. (min) 5.00 Outflow (cfs) 0.3 50 ft. Overland Flow Design Year Flaw 50 Area (aaes) 0.63 Ct = 0.15 Imperoious Area (sq ft) 6092 L= 50 ft. 'C' Factor 0.32 n= 0.40 50-year Volume Provided 296.5 S= 0.020 Area • C 0.202 Tc = 2.93 min., by Equation 3-2 of Guidelines Time Time Inc, Intens. Q Devel. Vol.ln Vol.Out Storage 210 ft. Gutter flow (min) (sec) (infir) (cfs) (cu ft) (cu ft) (cu ft) Z1 = 50.0 5.00 300 4.58 0.92 371 90 281 Z2 = 3.5 n= 0.016 5 300 4.58 0.92 371 90 281 S= 0.016 10 600 3.20 0.65 453 180 273 15 900 2.45 0.49 495 270 125 d= 0,221 ft. 20 1200 1.95 0.39 512 360 152 25 1500 1.62 0.33 523 450 73 A R Q Tc Tc total I Qc 30 1800 1.56 0.31 598 540 58 35 2100 1.28 0.26 568 630 -62 1.34 0.11 3.52 1.29 5.00 4,58 0.92 40 2400 1.19 0.24 598 720 -122 45 2700 1.08 0.22 610 810 -200 Qpeak for Case 1= 0.92 cfs 50 3000 0.99 0.20 619 900 -281 55 3300 0.92 0.19 631 990 -359 60 3600 0.87 0.18 649 1080 -431 CASE 2 65 3900 0,82 0.17 662 1170 -508 70 4200 0.80 0.16 694 1260 -566 Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.77 0.16 714 1350 -636 peak flow =.90(4.58)(Imp. Area) = 0.58 cfs 80 4800 0.75 0.15 741 1440 -699 85 5100 0.72 0.15 755 1530 -775 90 5400 0.71 0.14 788 1620 -832 So, the Peak flow for the Basin is the greater of the two flows, 95 5700 0.69 0.14 807 1710 -903 0.92 cfs 100 6000 0.67 0.14 824 1800 -976 208' DRAINAGE POND CALCULATIONS Required '208' Slorage Volume = Impervious Area x.5 in ! 12 iNft 254 cu ft 50 year Volume Provided 296.5 cu ft DRYWELL REQUIREMENTS - 50 YEAR DESIGN STORM Maximum Storage Required by Bowstring 281 cu ft Number and Type of Drywells Required 1 Single 0 Double INLAND PACIFIC ENGINEERING 50-year STORM BOWSTRING METHOD PROJECT: Riven+ralk 9th Addition PEAK FLOW CALCULATION PROJECT Riverwalk 9th Addition DETENTION BASIN DESIGN BASIN: H BASIN: H DESIGNER: S. Murphy Tot. Area 0.07 Aaes DATE: 09l15 Imp. Area 3188 SF C = 0.90 Time Increment (min) 5 CASE 1 Time of Conc. (min) 5.04 Outflow (ds) 0 40 ft. Overland Flow Design Year Flow 50 Area (acres) 0.01 Ct = 0.15 Impervious Area (sq ft) 3188 L= 40 ft. 'C' Factor 0,9 n= 0.40 50-year Volume Provided 136 S= 0.020 Area' C 0.063 Tc = 2.56 min., by Equation 3-2 of Guidelines Time Time Inc. Intens. Q Devel, Vol.ln Vol.Oul Storage 143 ft Gutter flow (min) (sec) (iNhr) (cfs) (cu ft) (cu ft) (cu ft) Z1= 50.0 5.00 300 4.58 0.29 116 0 116 Z2 = 3.5 n= 0.016 5 300 4.58 0.29 116 0 116 S= 0.011 10 600 3.20 0.20 142 0 142 15 900 2.45 0.15 155 0 155 d= 0.093 ft. 20 1200 1.95 0.12 160 0 160 25 1500 1.62 0.10 164 0 164 A R Q Tc Tc total I Qc 30 1800 1.56 0.10 187 0 187 35 2100 1.28 0.08 178 0 178 0.23 0.05 0.29 1.89 5.00 4.58 0.29 40 2400 1.19 0.07 187 0 167 45 2700 1.08 0.07 191 0 191 Qpeak for Case 1= 0.29 cfs 50 3000 0.99 0.06 193 0 193 55 3300 0.92 0.06 197 0 197 60 3600 0.87 0.05 203 0 203 CASE 2 65 3900 0.82 0.05 207 0 207 70 4200 0.80 0.05 217 0 217 Case 2 assumes a Time of Concentration less ihan 5 minutes so that the 15 4500 0.77 0.05 223 0 223 peak flow =.90(4.58)(Imp. Area) = 0.30 cfs 80 4800 0.75 0.05 232 0 232 85 5100 0.72 0.05 236 0 236 90 5400 0.71 0,04 246 0 246 So, the Peak flow for the Basin is the greater of the two flows, 95 5700 0.69 0.04 252 0 252 0.30 cfs 100 6000 0.67 0.04 258 0 258 208' DRAINAGE POND CALCULATIONS Required '208' Storage Volume = Impervious Area x.5 in I 12 inlfl 133 cu ft 50 year Volume Provided 136 cu ft DRYWELL REQUIREMENTS -10 YEAR DESIGN STOR Maximum Storage Required by Bowstring 236 cu ft Number and Type of Drywells Required 0 Single ERR Double INLAND PACIFIC ENGINEERING 50-year STORM BOWSTRING METHOD PROJECT: Riverwalk 9th Addition PEAK FLOW CALCULATION PROJECT Riverwalk 9th Addition DETENTION BASIN DESIGN BASIN: I BASIN: I DESIGNER: S. Murphy Tot. Area 0.46 Acres DATE: 09115 Imp. Area 5412 SF C = 0.36 Time Inaement (min) 5 CASE 1 Time af Conc. (min) 5.00 Outflow (cis) 0.3 40 ft. Overland Flow Design Year Flow 50 Area (aaes) 0.46 Ct = 0.15 Impervious Area (sq ft) 5472 L= 40 ft. 'C' Fador 0.36 n= 0.40 50-year Volume Provided 231 ~ S= 0.020 No8 f C 0.16 Tc = 2.56 min., by Equation 3-2 of Guidelines Time Time Inc. Intens. Q Devel. Vol.ln Vol.Out Storage 143 ft. Gutter flow (min) (sec) (infir) (cfs) (cu ft) (cu ft) (cu ft) - - Z1= 50.0 5.00 300 4.58 0.76 305 90 215 Z2 = 3.5 n= 0.016 5 300 4.58 0.76 305 90 215 S= 0.011 10 600 3.20 0.53 372 180 192 15 900 2.45 0.41 407 270 137 d= 0.133 ft. 20 1200 1.95 0.32 420 360 60 25 1500 1.62 0.27 430 450 -20 A R Q Tc Tc total I Qc 30 1800 1.56 0.26 491 540 -49 35 2100 1.28 0.21 467 630 -163 0.47 0.07 0.76 1.49 5.00 4.58 0.76 40 2400 1.19 0.20 491 720 -229 45 2700 1.08 0.18 501 810 -309 Qpeak for Case 1= 0J6 cfs 50 3000 0.99 0.16 509 900 -391 55 3300 0.92 0.15 518 990 -472 60 3600 0.81 0.14 533 1080 -547 CASE 2 65 3900 0.82 0.14 543 1170 -627 70 4200 0.80 0.13 570 1260 -690 Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.77 0.13 581 1350 -763 peak flow =.90(4.58)(Imp. Area) = 0.52 cfs 80 4800 0.75 0.12 609 1440 -831 85 5100 0.72 0.12 620 1530 -910 90 5400 0.71 0.12 647 1610 -973 So, the Peak flow for Ihe Basin is the greater of the two flows, 95 5700 0.69 0.11 663 1710 -1047 0.76 cfs 100 6000 0.67 0.11 677 1800 -1123 208' DRAINAGE POND CALCULATIONS Required'208' Storage Volume = Impenrious Area x,5 in I 12 iNft 228 cu ft 50 year Volume Provided 231 cu ft DRYYYELL REQUIREMENTS -10 YEAR DESIGN STOR Maximum Storage Required by Bowstring 215 cu ft Number and Type of Drywells Required 1 Single 0 Double INLAND PACIFIC ENGINEERING 50-year STORM BOWSTRING METHOD PROJECT: Riveneralk 9lh Addiiion PEAK FLOW CALCULATION PROJECT Riverwalk 9th Addition DETENTION BASIN DESIGN BASIN: J BASIN: J DESIGNER: S. Murphy Tot. Area 0.92 Acres DATE: 09115 Imp. Area 5998 SF C = 0.14 Time Increment (min) 5 CASE 1 Time of Conc. (min) 6.49 Outflow (cfs) 0.3 50 ft. Overland Flow Design Year Flow 50 Area (acres) 0.92 Ct = 0.15 Impenrious Area (sq ft) 5998 L= 50 ft. 'C' Fador 0,14 n= 0.40 50-year Volume Provided 274.5 S= 0.020 Area' C 0.129 Tc = 2.93 min., by Equation 3-2 of Guidelines Time Time Inc. Intens. Q Devel, Vol.ln Vol.Out Storage 311 ft. Gutter flow (min) (sec) (iNhr) (cfs) (cu ft) (cu ft) (cu fl) Z1= 50.0 6.49 389 4.07 0.52 273 117 156 Z2 = 3.5 n= 0.016 5 300 4.58 0.59 237 90 147 S= 0.011 10 600 3.20 0.41 302 180 122 15 900 2.45 0.32 326 270 56 d= 0.116 ft. 20 1200 1.95 0.25 335 360 -25 25 1500 1.62 0.21 341 450 -109 A R Q Tc Tc total I Qc 30 1800 1.56 0.20 388 540 -152 35 2100 1.28 0.16 366 630 -262 - 0.36 0.06 0.52 3.56 6.49 4.07 0.52 40 2400 1.19 0.15 387 720 -333 45 2700 1.08 0.14 394 810 -416 Qpeak for Case 1= 0.52 cfs 50 3000 0.99 0.13 399 900 -501 55 3300 0.92 0.12 407 990 -583 60 3600 0.87 0.11 418 1060 -662 CASE 2 65 3900 0.82 0.11 426 1170 -744 70 4200 0.80 0.10 446 1260 -814 Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.77 0.10 459 1350 -891 peak flow = 90(4.58)(Imp. Area) = 0.57 cfs 80 4800 0.75 0.10 476 1440 -964 85 5100 0.12 0.09 485 1530 -1045 90 5400 0.71 0.09 506 1620 -1114 So, the Peak flow for the Basin is the greater o( the two 8ows, 95 5700 0.69 0.09 518 1710 -1192 0.57 cfs 100 6000 0.67 0.09 529 1800 -1271 208' DRAINAGE POND CALCULATIONS Required '208' Storage Volume = Impervious Area x.5 in I 12 inlft 250 cu ft 50 year Volume Provided 274.5 cu ft DRYWELL REQUIREMENTS -10 YEAR DESIGN STOR Maximum Storage Required by Bowstring 156 cu ft Number and Type oi Drywells Required 1 Single 0 Double INLAND PACIFIC ENGINEERING 50-year STORM BOWSTRING METHOD PROJECT: Riverwalk 9th Addition PEAK FLOW CALCULATION PROJECT Riverwalk 9th Addition DETENTION BASIN DESIGN BASIN: K BASIN: K DESIGNER: S. Murphy Tot. Area 0.09 Acres DATE: 09115 Imp. Area 3908 SF C = 0.90 Time Inaement (min) 5 CASE 1 Time of Conc. (min) 5.00 Outflow (cfs) 0 50 ft. Overland Flow Design Year Flow 50 Area (aaes) 0.09 Ct = 0.15 Imperoious Area (sq ft) 3908 L= 50 ft. 'C' Factor 0.9 n= 0.40 '208' Volume Provided 185 S= 0.020 Area' C 0.081 Tc = 2.93 min., by Equation 3-2 of Guidelines Time Time Inc. Intens. Q Devel, Vol.ln Vol.Out Storage 143 ft. Gutter flow (min) (sec) (iNhr) (cfs) (cu ft) (cu ft) (cu ft) Z1 = 50.0 5.00 300 4.58 0.37 149 0 149 Z2 = 3.5 n= 0.016 5 300 4.58 0.31 149 0 149 S= 0.011 10 600 3.20 0.26 182 0 182 15 900 2.45 0,20 199 0 199 d= 0.102 ft. 20 1200 1.95 0.16 206 0 206 25 1500 1,62 0.13 210 0 210 A R Q Tc Tc total I Qc 30 1800 1.56 0.13 240 0 240 35 2100 1.28 0,10 226 0 228 0.28 0.05 0.37 1.78 5.00 4.58 0.37 40 2400 1.19 0.10 240 0 240 45 2700 1.08 0.09 245 0 245 Qpeak for Case 1= 0.37 cfs 50 3000 0.99 0.08 249 0 249 55 3300 0.92 0.07 254 0 254 60 3600 0.87 0.07 261 0 261 CASE 2 65 3900 0.82 0.07 266 0 266 70 4204 0.80 0.06 279 0 279 Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.77 0.06 287 0 287 peak flow =.90(4.58)(Imp. Area) = 0.37 cfs 80 4800 0.75 0.06 298 0 298 85 5100 0.72 0.06 303 0 303 90 5400 0.71 0.06 316 0 316 So, the Peak flow for the Basin is lhe greater oi the two flows, 95 5700 0.69 0,06 324 0 324 0.37 cfs 100 6000 0.67 0.05 331 0 331 208' DRAINAGE POND CALCULATIONS Required'208' Storage Volume = Impervious Area x,5 in ! 12 inlft 163 cu ft 50 year Volume Provided 185 cu ft ORYWELL REQUIREMENTS -10 YEAR DESIGN STOR Maximum Storage Required by Bowstring 303 cu ft Number and Type of Drywells Required 0 Single ERR Double INLAND PACIFIC ENGINEERING 50-year STORM BOWSTRING METHOD PROJECT: Riverwalk 9th Addition PEAK FLOW CALCULATION PROJECT Rivervvalk 9th Addition DETENTION BASIN DESIGN BASIN: HI & JK BASIN; HI & JK DESIGNER: S. Murphy Tot. Area 1,38 Acres DATE: 09118 Imp. Area 11470 SF C = 0.29 Time Inaement (min) 5 CASE 1 Time af Conc. (min) 5.02 OuHlow (cfs) 1 50 R. Overland Flow Design Year Flow 50 Area (aaes) 1.38 Ct = 0.15 Impervious Area (sq ft) 11470 L= 50 ft. 'C' Factor 0.29 n= 0,40 '208' Volume Provided 505.5 S= 0.020 Area' C 0,400 Tc = 2.93 min., by Equation 3-2 of Guidelines Time Time Inc. Intens. Q Devel. Vol,ln Vol.Out Storage 250 ft. Gutter flow (min) (sec) (iNhr) (cfs) (cu ft) (cu ft) (cu ft) Z1 = 50.0 5.02 301 4.57 1.83 738 301 437 Z2 = 3.5 n= 0.016 5 300 4.58 1,83 737 300 437 S= 0.011 10 600 3.20 1.28 899 600 299 15 900 2.45 0.98 983 900 83 d= 0.185 it. 20 1200 1.95 0.78 1016 1200 -184 25 1500 1.62 0.65 1039 1500 -461 A R Q Tc Tc lotal t Qc 30 1800 1.56 0.62 1188 1800 -612 - 35 2100 1.28 0.51 1128 2100 -972 0.92 0.09 1.83 2.09 5.02 4.57 1.83 40 2400 1,19 0.47 1187 2400 -1213 45 2700 1.08 0.43 1211 2700 -1489 Qpeak for Case 1= 1.83 cfs 50 3000 0.99 0.40 1229 3000 -1771 55 3300 0.92 0.37 1253 3300 -2047 60 3600 0.67 0.35 1289 3600 -2311 CASE 2 65 3900 0.82 0.33 1313 3900 -2587 70 4200 0.80 0.32 1377 4200 -2823 Case 2 assumes a Time oi Concentration less than 5 minutes so that the 75 4500 0.77 0.31 1416 4500 -3082 peak flow =.90(4.58)(Imp. Area) = 1.09 cfs 80 4800 0,75 0.30 1471 4800 -3329 85 5100 0,72 0.29 1499 5100 -3601 90 5400 0,71 0.28 1563 5400 -3837 So, the Peak flow for the Basin is the greater of the two flows, 95 5700 0.69 0,28 1602 5700 -4098 1.83 cfs 100 6000 0.67 027 1636 6000 -4364 208' DRAINAGE POND CALCULATIONS Required'208' Storage Volume = Impervious Area x.5 in I 12 iNft 478 cu ft 50 year Volume Provided 505.5 cu ft DRYWELL REQUIREMENTS -10 YEAR DESIGN STOR Maximum Storage Required by Bowstring 437 cu ft Number and Type of Drywells Required 0 Single 1 Double INLAND PACIFIC ENGINEERING 50-year STORM BOWSTRING METHOD PROJECT: Riverwalk 91h Addition PEAK FLOW CALCULATION PROJECT Rivenhralk 9th Addition DETENTION BASIN DESIGN BASIN: P BASIN: P DESIGNER: S. Murphy Tot. Area 0.31 Acres DATE: 03123 Imp. Area 6502 SF C = 0.59 Time Increment (min) 5 CASE 1 Time of Conc, (min) 5.00 Outflow (cfs) 0.3 45 ft. Overland Flow Design Year Flow 50 Area (acres) 0.31 Ct = 0.15 Impervious Area (sq ft) 6502 L= 45 ft. 'C Factor 0.59 n= 0.02 '208' Volume Provided 271 S= 0.020 Area ' C 0,183 Tc = 0.40 min., by Equation 3-2 of Guidelines Time Time Inc. Intens. Q Devel. Vol.ln Vol.Out Storage 120 ft. Gutter flow (min) (sec) (in/hr) (cfs) (cu ft) (cu ft) (cu ft) Z1 = 50.0 5.00 300 4.58 0.84 337 90 247 Z2 = 1 n= 0.016 5 300 4.58 0.84 337 90 247 S= 0.011 10 600 3.20 0.59 411 160 231 15 900 2.45 0.45 449 270 179 d= 0.141 ft. 20 1200 1,95 0.36 464 360 104 25 1540 1.62 0.30 475 450 25 A R Q Tc Tc total I Qc 30 1800 1.56 0.29 543 540 3 = - 35 2100 1.28 0.23 516 630 -114 - 0.51 0.07 0.84 1.21 5,00 4.58 0.64 40 2400 1.19 0,22 542 720 -178 45 2700 1.08 0.20 553 810 -257 Qpeak for Case 1= 0.84 cfs 50 3000 0.99 0.18 562 900 -338 55 3300 0.92 0.11 572 990 -418 60 3600 0.87 0.16 589 1080 -491 CASE 2 65 3900 0.82 0.15 600 1170 -570 70 4200 0.80 0.15 629 1260 -631 Case 2 assumes a Time of Conoentration less than 5 minutes so that the 75 4500 0.77 0.14 648 1350 -702 peak flow =.90(4.58)(Imp. Area) = 0.62 cfs 80 4800 0.75 0.14 672 1440 -768 85 5100 0.72 0.13 685 1530 -845 90 5400 0.71 0.13 714 1620 -906 So, the Peak flow for the Basin is the greater of the two flows, 95 5700 0.69 0.13 732 1710 -978 0.84 cfs 100 6000 0,67 0.12 748 1800 -1052 208' DRAINAGE POND CALCULATIONS Required '208' Storage Volume = Impervious Area x.5 in 112 in/ft 271 cu ft 50 year Volume Provided 271 cu ft DRYWELL REQUIREMENTS • 10 YEAR DESIGN STOR Maximum Storage Required by Bowstring 247 cu ft Number and Type of Orywells Required 1 Single 0 Doub4e INLAND PACIFIC ENGINEERING RIVERWALK 9TH 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* Qa/La'* Q!(QalLa) Remarks H 15+25 L 3188 0.21 0.0110 4.0160 50 3125 0.08 0.054 3,86 Need 1- 4' curb inlet K 16+59 L 5998 0.39 0.0110 0.0160 50 3125 0.10 4.069 5,68 Need 2- 4' curb inlets P 29+32 L 6502 0.56 0.0080 0.0160 50 3125 0.12 0.065 6,86 Need 2- 4' curb inlets