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Ditch Sizing - Ditch E1 -E1 <br />The following peak flow for Ditch Section E1 -E1 was obtained from Exhibit 20, page CRDA1 -10. <br />Location of ditch section E1 -E1 can be found on Exhibit 9C. <br />Rip rap is sized in Excel due to SedCad 4.0 inability to handle a flow of 23 cfs and a slope of 17 %. <br />Flow <br />(cfs) <br />Ditch Section E -E 23.3 LICE <br />srov� ENS 9 � <br />cc <br />10% P� <br />Manning's Equation <br />Flow In a Trapezoidal Channel <br />DEPTH <br />D <br />0.63 <br />FEET <br />WIDTH <br />W <br />3 <br />FEET <br />Slope <br />S <br />0.167 <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)= <br />WETTED PERIMETER= (W) +2 *[((X *D)2 +D2)v2] <br />R= AREA/WETTED PERIMETER <br />V= (1.49 /N) *(R213) *(Sai2)= <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 = 0.81 feet 9.7 inches <br />2.49 Feet2 <br />5.27 Feet <br />0.47 <br />9.22 Ft/Sec <br />22.92 CFS <br />23.30 CFS <br />PR -5 CRDA1 -15 ( New 05/12) <br />