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East Diversion Ditch - 30% Channel Segment <br /> Manning's Equation <br /> Flow In a Trapezoidal Channel <br /> Depth D 0.6 Feet <br /> Width W 3 Feet* <br /> Slope S 0.3 Express as Decimal <br /> Mannings "N" N 0.04 Express as Decimal <br /> Side Slope X 0.5 Slope = X:1 <br /> AREA=(W*D)+(X*D"2)= 1.98 FEET"2 <br /> WETTED PERIMETER=(W)+2*[((X*D)"2+D^2)^0.5] 4.34 FEET <br /> R=AREA/WETTED PERIMETER 0.46 <br /> V=(1.49/N)*(R^.667)*(S^.5)= 11.47 FT/SEC <br /> Q = AXV = 22.71 CFS <br /> Q REQUIRED - Peak Discharge 21.75 CFS <br /> Riprap Sizing - Ditch D-3 <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 = 1.47 feet 18 inches Use 18" Rock <br /> *Minimum Bottom Width <br /> TR-91 App. B-60i 01/15 <br />