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• <br /> DUGOUT POND <br /> EMERGENCY SPILLWAY <br /> MANNING'S EQUATION <br />FLOW IN A TRAPI ZODIAL CHANNEL <br />DEPTH D 0.160 FEET <br />WIDTH W 1.000 FEET (BOTTOM) <br />SLOPE S 0.010 EXPRESS AS DECIMAL <br />"N" N 0.040 EXPRESS AS DECIMAL <br />SIDE SLOPE X 1.500 SLOPE = X:1 <br />AREA=(W*D)+(X*D^2)= 0.20 FEET^2 <br />WETTED PERIMETER=(W)+2((XD^ 2+D^2))^.5 1.58 FEET <br />R=AREA/WETTED PERMITER 0.13 <br />V=(1.49/N)*(R^.667)*(S^.5)= 0.94 FT/SEC <br />Q = A X V = 0.19 CFS <br />Q REQUIRED 0.16 CFS <br />The spillway for the dugout pond is a trapazoidal <br />channel 1.0 feet wide and 0.16 feet deep <br />with a freeboard of 12" for a total depth of 1.160 <br />feet. Rip rap is not required as demonstrated below. <br />The spillway channel is well vegetated all the way to <br />the tracks below so erosion of the channel should not be <br />a concern. <br />• <br />r1 <br />LJ <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 = 0.003 feet <br />0.038 inches <br />-~- <br />