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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 <br />0.930 <br />FEET <br />WIDTH W <br />5.000 <br />FEET <br />Slope S <br />0.020 <br />EXPRESS AS DECIMAL <br />Mannings "N" N <br />0.030 <br />EXPRESS AS DECIMAL <br />SIDE SLOPE X <br />2.000 <br />SLOPE = X:1 <br />AREA= (W *D) +(X *D`)= <br />6.38 Feet` <br />WETTED PERIMETER= (W) +2 *[((X *D) ° +D`) ° °) <br />9.16 Feet <br />R= AREA/WETTED PERIMETER <br />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)/7.58)) ^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 />