1992-07-01_REVISION - C1991078 - Laserfiche WebLink

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Collection Ditches Collection Ditch CD-lE Flow In a Triangular Channel DEPTH D 1.400 FEET SLOPE S 0.020 EXPRESS AS DECIMAL Mannings "N" N 0.035 EXPRESS AS DECIMAL SIDE SLOPE X 2 .000 SLOPE = X: 1 AREA=(W*D) +(X*D^2)= ✓3 .92 FEET^2 WETTED PERIMETER=(W)+2 ( (XD^2+D^2) ) ^ .5 ✓6.26 FEET R=AREA/WETTED PERMITER ✓0. 63 V=(1.49/N) * (R^ . 667) * (S^ . 5)= ✓4 .41 FEET/SEC ✓17.27 CFS Q = A X V = 16.99 CFS Q REQUIRED Collection Ditch CD-lE will be a triangular channel 1.400 feet deep with 2h: ly side slopes. With a freeboard of 0. 3 ' the total depth of the collection ditch is 1.700 feet. The flow velocity is slow enough that erosion will not be a problem. Collection Ditch CD-2E Flow In a Triangular Channel DEPTH D 1. 000 FEET SLOPE S 0.020 EXPRESS AS DECIMAL Mannings "N" N 0.035 EXPRESS AS DECIMAL • SIDE SLOPE X 2 . 000 SLOPE = X: 1 AREA=(W*D) +(X*D^2)= ✓2 . 00 FEET^2 WETTED PERIMETER=(W)+2 ( (XDA2+D^2) ) A . 5 ✓4 .47 FEET R=AREA/WETTED PERMITER A. 45 V=(1. 49/N) * (RA . 667) * (S^ . 5) = ✓3 . 52 FEET/SEC Q = A X V = ✓7 . 04 CFS Q REQUIRED 6.78 CFS Collection Ditch CD-2E will be a triangular channel 1. 000 feet deep with 2h: ly side slopes. With a freeboard of 0. 3 ' the total depth of the collection ditch is 1. 300 feet. The flow velocity is slow enough that erosion will not be a problem. Collection Ditch CD-3E Flow In a Triangular Channel DEPTH D 0.800 FEET SLOPE S 0. 020 EXPRESS AS DECIMAL Mannings "N" N 0.035 EXPRESS AS DECIMAL SIDE SLOPE X 2 . 000 SLOPE = X: 1 AREA=(W*D)+(X*D^2)= ✓// 1.28 FEET^2 WETTED PERIMETER=(W)+2 ( (XD^2+DA2) ) ^. 5 ✓3 .58 FEET R=AREA/WETTED PERMITER ✓'. 36 V=(1. 49/N) * (R^ . 667) * (S^ . 5)= 3 . 03 FEET/SEC Q = A X V = /3 .88 CFS • Q REQUIRED 3 .84 9-31 July 1992