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Peak Flow Calculations <br />The following peak flow calculations were compiled with SEDCAD. <br />Details of the run -off calculations are shown on the following pages. <br />25 -YR <br />24 HR <br />Event <br />Pond F Drainage 55.6 <br />Flow calculations for the site ditches and culverts are <br />presented in following sections of this exhibit. <br />Spillway Pond F <br />Pond F Emergency Spillway <br />Manning's Equation <br />Flow In a Trapezoidal Channel <br />DEPTH D 0.9 <br />FEET <br />WIDTH W 10 <br />FEET <br />Slope S 0.02 <br />EXPRESS AS DECIMAL <br />Mannings "N" N 0.03 <br />EXPRESS AS DECIMAL <br />SIDE SLOPE X 2 <br />SLOPE = X:1 <br />AREA= (W *D) +(X *D Z)= <br />9.95 Feet2 <br />WETTED PER IMETER= (W) +2 *[((X *D) 2 +D2)112] <br />13.80 Feet <br />R= AREA/WETTED PERIMETER <br />0.72 <br />V= (1.49 /N) *(R213) *(S112)= <br />5.65 Ft/Sec <br />Q =AXV= <br />56.1 CFS <br />Q REQUIRED - Peak Discharge <br />55.6 CFS <br />Riprap Sizing - Across top of Embankment <br />D50 = Size of Riprap <br />D50 = ((V X S ^.17)17.58)) ^2 <br />D50 = Diameter in feet <br />V = Velocity <br />S = Slope <br />D50 = 0.15 feet 1.76 <br />inches Use Pit Run Material <br />TR -81 App. B -7 10/13 <br />