Laserfiche WebLink
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 24.77 33.56 <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 <br />D <br />0.930 <br />FEET <br />WIDTH <br />W <br />5.000 <br />FEET <br />Slope <br />S <br />0.020 <br />EXPRESS AS DECIMAL <br />Mannings "N" <br />N <br />0.030 <br />EXPRESS AS DECIMAL <br />SIDE SLOPE <br />X <br />2.000 <br />SLOPE = X:1 <br />AREA= (W *D) +(X *D')= <br />WETTED PERIMETER= (W) +2 *[((X *D)' +D2)112] <br />R= AREA/WETTED PERIMETER <br />V= (1.49/N) *(R211) *(Sin)= <br />Q =AXV= <br />Q REQUIRED - Peak Discharge <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 <br />6.38 Feet' <br />9.16 Feet <br />0.70 <br />5.52 Ft/Sec <br />35.21 CFS <br />33.56 CFS <br />1.7 inches None Required <br />TR -91 Volume XI, App. B -6 12/14 <br />