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PEAK FLOW CALCULATIONS <br />The following peak flow calculations were compiled with the computer program SEDCAD <br />version 4.0. Details of the run -off calculations are shown on the following pages. <br />10 -YR 25 -YR <br />24 HR 24 HR <br />Event Event <br />Pond J Drainage 22.97 31.00 <br />Flow calculations for "J" ditches and culverts are presented in following sections of this exhibit. <br />Spillway Pond J <br />Manning's Equation <br />Flow In a Trapezoidal Channel <br />DEPTH D 0.930 FEET <br />WIDTH W 5.000 FEET <br />Slope S 0.020 EXPRESS AS DECIMAL <br />Mannings "N" N 0.030 EXPRESS AS DECIMAL <br />SIDE SLOPE X 2.000 SLOPE = X:1 <br />AREA= (W *D) +(X *D`)= 6.38 Feet <br />WETTED PERIMETER= (W) +2 *[((X *D)` +D`) ."] 9.16 Feet <br />R= AREANVETTED PERIMETER 0.70 <br />V= (1.49 /N) *(R-- ) *(S "`)= 5.52 Ft/Sec <br />Q =AXV= 35.21 CFS <br />Q REQUIRED - Peak Discharge 31.00 CFS <br />Spillway Pond J <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 = 0.14 feet 1.7 inches None Required <br />TR -84 Volume XI, App. B -6 12/13 <br />