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Ditch 3 -12% Chanel - Reclaimed Configuration <br />The following peak flow for Ditch 3 (12 %) was obtained from SedCad, page 14 -6 -121 <br />Location of Ditch 3 can be found on Exhibit 8C. <br />Flow <br />(cfs) <br />Ditch D3 18.7 <br />Manning's Equation <br />Flow In a Trapezoidal Channel <br />DEPTH <br />D <br />0.62 <br />FEET <br />WIDTH <br />W <br />3 <br />FEET <br />Slope <br />S <br />0.12 <br />EXPRESS AS DECIMAL <br />Mannings "N" <br />N <br />0.04 <br />EXPRESS AS DECIMAL <br />SIDE SLOPE <br />X <br />1.5 <br />SLOPE = X:1 <br />AREA= (W *D) +(X *D2)= 2.44 Feet2 <br />WETTED PERIMETER= (W) +2 *[((X *D)2 +D2)112) 5.24 Feet <br />R= AREA/WETTED PERIMETER 0.47 <br />V= (1.49 /N) *(R2J3) *(S'l2)= <br />7.75 <br />Ft/Sec <br />Q =AXV= <br />18.88 <br />CFS <br />Q REQUIRED - Peak Discharge 18.69 CFS <br />Riprap Sizing <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 = 0.51 feet <br />6.1 inches 12" In -Place <br />PR -5 14 -6 -127 (Rev. 05/12) <br />