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• Sediment Pond 9, P-9 <br />THREE YEAR SEDIMENT VOLUME ACRE FEET <br />15.9 Acres 115 #/Cubic Feet <br />TOTAL REQUIRED SEDIMENT POND 9 CAPACITY -- AF <br />PEAK FLOW CALCULATIONS <br />POND 9 <br />SPILLWAY <br />DRAINAGE AREA (ACRES) 15.9 <br />CURVE N0. 74.00 <br />STORM EVENT YR., 24 HR. 25 <br />STORM EVENT in. 2.2 <br />RUNOFF in. 0.45 <br />wATERSHED RELIEF ft. 126 <br />Lc 25 ft. 1900 <br />Lc 50 ft. 1875 <br />Lc 75 ft. 560 <br />WATERSHED SLOPE 19.72 <br />SLOPE ADJUSTMENT FACTOR 1.04 STEEP <br />LENGHT OF WATERSHED 1330 <br />EQUIVALENT DRAINAGE AREA 22 <br />PEAR FLOW efs/in Fig D-2 27.5 <br />• ADJUSTED PEAK FLOW 9.31 CFS <br />POND 9 EMERGENCY SPILLWAY <br /> <br />0.05 <br />0.39 <br />The invert of the existing 18"CMP spillway is at <br />elevation 7511.5. The top of the pond embankment <br />is at elevaton 7515. Design the invert of the <br />emergency spillway at elevation 7513.5. <br />MANNING'S EQUATION <br />FLOW IN A TRAPEZOIDAL CHANNEL <br />ENTER DEPTH D 0.500 FEET <br />ENTER WIDTH W 5.500 FEET <br />ENTER SLOPE S 0.020 DECIMAL <br />ENTER "N" N 0.040 DECIMAL <br />ENTER SIDE SLOPE Y 2.000 SLOPE = Y :1 <br />AREA=iW*D1+(k*D"2f= 3.25 FEET"2 <br />WETTED PERIMETER=(W1+2((YD"2+D"21i". 7.74 FEET <br />R=AREA/WETTED PERMITER 0.42 <br />V=(1.49/N)#(R".6671*lS".51= 2.95 FT/SEC <br />• Q = A Y V = 9.60 CFS <br />Q REQUIRED 9.31 CFS <br />P-9-2 New 7-11-91 <br />