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I• <br />Criteria: 25 yr- 24 hr Storm Event = 3.4" <br />Minimal Run-off into Pond <br />Peak Mine Water Flow into Pond = 4000GPM = 8.9 cfs <br />Spillway Capacity > Mine Water Inflow + 25 yr 24 hr Storm Event <br />POND 001 -EMERGENCY SPILLWAY DESIGN <br />For Open Channel Flow <br />Q = <br />Where: Q =Flow <br />Cm =Constant = 1.49 (English Units) <br />A, =Area Dedicated to Mine Water Inflow <br />R = Area/Wetted Perimeter <br />S = Channel Bottom Out Slope <br />• <br />• <br />N = Manning's Roughness Factor = 0.29 for Gravel <br />A, _[8.6(48 +2(3.4)) +(8.6)(8.6)] / 144 A, = 3.79 FtZ <br />R = 3.79/ [48 + 6.8 + 2(2(8.6)12) / 12] R = 0.68 <br />Q =[(1.49) / 0.029] (3.79) (0.68) (0.1)12 Q = 35.1 cfs <br />C A, R~ S'2 (Modified Manning's Equation) <br />N <br />Safety Factor = 35.1 cfs / 8.9 cfs SF = 3.9 <br />TR-49 <br />2.05-16c <br />2/14/07 <br />