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Use ditch section described: <br />• Runoff = 1.25" (CN91, 2.1" rainfall; <br />Reference #2) <br />Peak Flow (16% slope) = 195 cfs/inch runoff <br />(pg. D-5, ref. #2) <br />Adjust to 11% slope <br />195 x 0.89 = 174 cfs/in runoff (Table E-1,Ref.#2) <br />Peak Flow - <br />174 cfs/in x 1.25 = 217 cfs <br />The discharge curve on Exhibit U shows combined discharge from the primary <br />and emergency spillways. At elevation 7386, this is approximately 220 cfs. <br />• 10' bottom <br />2:1 side slope <br />n = 0.035 <br />Then <br />d = 0.8 ft. <br />q = 81 cfs <br />v = 9.4 fps <br />Riprap will be required to control erosion. <br />Ditch will be 3 feet deep. <br />2) Perimeter Ditch Around Pond <br />Drainage Area <br />• North Side - 93.4 Acres <br />South Side - 160 Acres <br />