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<br />MR. NIICIrnrr 511VAGG <br />Page 6 <br />January 7, 1981 <br />Pond 1 <br />Draina~~c - G00' x 290' = 3.99 acres <br />Consider the surface to be a road <br />c = 92 <br />CN 92, 3.0" storm yields 2.16" of runoff <br />2.16" x 3.99 acres = 8.62 acres inches = .72 acre/f t. <br />_ .7 <br />7 Runoff storage required <br />Sediment storage <br />Use .1 ac/ft per acre <br />.1 ac/ft x 3.99 acres = 3.99 ac/ft <br />_ .4 ac/ft <br />7bta1 Pond size = .7 + .4 = 1.1 ac/ft <br />Pond 2 <br />%00' x 120' = 1.93 acres <br />CN = 92, 3.0" storm yields 2.16" of runoff <br />2.].G" x 1.93 acres = 4.17 acre inches <br />_ .35 ac/ft runoff storage <br />, sediment storage <br />.1 ac ft/ac x 1.93 acres = 1.93 ac/ft <br />'Ibtal Fund storage = .35 + .19 = .54 ac/ft <br />Collection Ditch 1-a, 1-b 2-a, 2-b <br />Grade - 1 percent <br />Peak dis~:harye 2.9(.5) = 1.9 cfs <br />n = .045 <br />Walls 1:2 slope <br />D = 2.67 1 1.9 <br />. , v 38.39 (.01)•5 <br />s <br />= 2.65 .495 <br />_ .77 feet = 9.6" <br />add 1/2" freeboard <br />= 1.6 inches <br />