Laserfiche WebLink
Sediment Pond Principal Spillway Size Calculation <br />Peak flow for 10 yr, 24 hr precipitation event <br />12 Acres - Slope 50% Curve Number 72 <br />16 Acres - Slope 4% Curve Number 90 <br />Slope Adjustment Factor 50% Slope 1.18 <br />Slope Adjustment Factor 4% Slope 1.0 <br />Peak Flow for 50% Slope 20 cfs/inch of runoff <br />Peak Flow for 4% Slope 14 cfs/inch of runoff <br />Assume that flows are not cumulative at sediment pond <br />Peak Flow for Disturbed Area 19 cfs <br />Peak Flow for Undisturbed ARea 9 cfs <br />Principal Spillway is 12" Diameter CMP <br />Flow from nomograph with no head condition - 2.2 cfs <br />Not applicable due to closed gate on principal spillway <br />• Peak flow for a 25-yr, 24-hr event <br />Precipitation - 2.8 inches <br />Peak flow is 14 cfs/inch of runoff <br />Slope adjustment factor - 1.0 <br />1.80 inches of runoff, CN 90 <br />25 cfs peak flow <br />i <br />_lg_ <br />