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Ditch 3 - 50% Chanel - Reclaimed Configuration <br />The following peak flow for Ditch 3 (50 %) 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 D <br />0.42 <br />FEET <br />WIDTH W <br />3 <br />FEET <br />Slope S <br />0.5 <br />EXPRESS AS DECIMAL <br />Mannings "N" N <br />0.04 <br />EXPRESS AS DECIMAL <br />SIDE SLOPE X <br />1.5 <br />SLOPE = X:1 <br />AREA= (W *D) +(X *D2)= <br />1.52 Feet2 <br />WETTED PERIMETER= (W) +2 *[((X *D)2 +D2)1/21 <br />4.51 Feet <br />R= AREA/WETTED PERIMETER <br />0.34 <br />V= (1.49 /N) *(R2j )*(S'i2)= <br />Q =AXV= <br />Q REQUIRED - Peak Discharge <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 = 2.24 feet <br />12.77 Ft/Sec <br />19.47 CFS <br />18.69 CFS <br />26.9 inches 24" In -place <br />PR -5 14 -6 -128 (Rev. 05/12) <br />