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PEAK FLOW CALCULATION EVERETT MONEY TF2EE <br />25-Year Design Storm POST DEVELOPED <br />WHIPPLE CONSULTING ENGINEERS <br />BY: JFS BASIN: TOTAL <br />DATE: 10/26/2010 <br />Tot. Area 10,800 SF 025 Acres <br />Imp. Area 9,600 SF Per. Area 1,200 5F <br />Weighted C 0.82 <br />Imp. C 0.9 <br />Per. C 0.15 <br />CASE 1 <br />140 ft. Overland Flow <br />Ct = 0.15 0.40 Natural 0.15 Overland <br />L = 140 ft. <br />n = 0.16 <br />S = 0.0150 <br />Tc = 3.42 min. <br />0 ft. Gutter flow <br />Z1 = <br />Z2 = <br />n= <br />S= <br />d= <br />A R <br />0.28 0.06 <br />Qpeak for Case 1 = <br />0.2 <br />40.0 <br />0.016 <br />0.0250 <br />0.1180 ft. <br />Q Tc <br />0.62 0.00 <br />0.62 cfs <br />For Z2 <br />Type B = 1.0 <br />Rolled = 3.5 <br />Flow Width 0.0 ft. <br />Tc total I Qc <br />5.00 3.05 0.62 <br />CASE 2 <br />Case 2 assumes a Time of Concentration less than 5 minutes so that the <br />peak flow =.90(3.05)(Imp. Area) = 0.63 cfs <br />So, the Peak flow for the Basin is the greater of tlie two flows, <br />0.63 cfs <br />