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REVISED <br />7/30/85 <br />Table 2 <br />SEDIMENTATION POND E DESIGN CALCULATIONS <br />(Continued) <br />Modified Universal Soil Loss Equation: <br />Y = 95 (Q gp) 0.56 K LS CP <br />= 95 ((1.52)(17.7)) 0.56(0.2)(2.80)(1.0)(1.0) <br />= 336 tons x 2000 (lbs/ton) / 60 (lbs/cu.ft.)/43,560(sq. ft/ac.) <br />= 0.26 ac -ft. <br />Required Sediment Volume: 0.26 ac -ft x (100/40) = 0.64 ac. ft. <br />Required Sediment Cleanout: When pond is 60°: full of sediment. <br />RUNOFF VOLUME: <br />1.8 in. rainfall and Curve Number 82 = 0.52 in. runoff <br />35 ac watershed x 0.52 (in. runoff)/12(in./ft.) = 1.52 ac -ft of runoff <br />volume <br />TOTAL VOLUME: <br />0.64 ac -ft of sediment volume + 1.52 ac -ft of runoff volume = 2.16 ac -ft <br />of total volume <br />EMERGENCY SPILLWAY: <br />- Design for 25 -yr, 24 -hr event = 2.2 in. rainfall <br />- 35 ac watershed <br />- AMC II Curve No. 82 <br />- Average slope of runoff area is 6 <br />- Slope correction factor = 1.11 <br />- 2.2 in. rainfall @ curve No. 82 = 0.83 in. runoff <br />PEAK FLOW: <br />31 cfs/in, runoff x 0.83 in. runoff x 1.11 = 28.6 cfs <br />in <br />