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• PEAK FLOW CALCULATIONS <br />THE FOLLOWING PEAK FLOW CALCULATIONS WERE COMPILED WITH <br />THE COMPUTER PROGRAM SEDCAD VERSION 4.0. DETAILS OF THE <br />RUN-OFF CALCULATIONS 4RE SHOWN ON THE FOL LOWING PAGES. <br />10-YR 25-YR <br />24 HR 24 HR <br />EVENT EVENT <br />POND I DRAINAGE 6.12 7.99 <br />POND 2 DRAINAGE 5.94 7.76 <br />FLOW CALCULATIONS FOR THE SITE DITCHES AND CULVERTS ARE <br />PRESENTED IN FOLLOWING SECTIONS OF THIS EXHIBIT. <br />SPILLWAY POND I <br /> EMERGENCY SPILLWAY <br /> FLOW IN A TRAPEZOIDAL CH ANNEL <br /> MANNINGS EQUATION <br /> DEPTH D 0.310 FEET <br /> WIDTH W 4.000 FEET <br />• SLOPE S 0.320 EXPRESS AS DECIMAL <br /> MANNINGS"N" N 0.030 EXPRESS AS DECIMAL <br /> SIDE SLOPE X 2.000 SLOPE = X:I <br /> AREA=(W"D)+(X"D~)= 1.43 FEET <br /> WETTED PERIMETER=(W)+2•[ ((X"D)~+D~)~~~] 5.39 FEET <br /> R=AREA/WETTED PERIMETER 0.27 <br /> V=(1.49/N)"(R~")•(S~~z)= 11.62 F T/SEC <br /> O=AX V= 16.64 CFS <br /> O REQUIRED -PEAK DISCHARGE 15.75 CFS <br />SPILLWAY POND I <br />RIPRAP SIZING -EMERGENCY SPILLWAY <br />D50 =SIZE OF RIPRAP <br />D50 = ((V X S'.I7)/7.58))'2 <br />D50 =DIAMETER IN FEET <br />V =VELOCITY <br />S =SLOPE <br />D50 = 1.59 FEET 19.1 INCHES <br /> <br />7k-37 <br />Vol SA -Tab Pond Volumes W - 7 - / o/,j/o [ 9/01 <br />