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DITCH CALCULATION <br /> (Using Chezy-Manning Equation) <br /> PROJECT: Premier Co-op Grain Bin 2015 <br /> FILE NUMBER: PC-03-15 <br /> LOCATION: Swale B <br /> Enter the channel characteristics(see Diagram 1): <br /> CHANNEL CROSS SECTION <br /> Minimum Channel Slope(S): 0.01 feet/feet <br /> 100 Year Design Flow(Q): 0.72 CFS ii; T"Ti=; _ <br /> ii <br /> Bottom Width (W): 2 feet <br /> Avg. Side Slope(X): 3 horiz./vert. _!-= -ifiEr <br /> Depth of Channel (Y): 0.75 feet <br /> Retardance Class: D ii ii= <br /> Manning's Number(N): 0.05 , =I%- <br /> �T ; =T =I <br /> The channel will behave as follows: W <br /> Hydraulic Radius(R): 0.20 feet <br /> Depth(D): 0.26 feet Diagram 1 <br /> Velocity(V): 1.01 feet/second <br /> 100 Year Peak Flow Rate: <br /> Using the Rational Method: <br /> Qtoo=CIA: 0.59 8.1 0.15 = 0.72 cfs <br /> C = 0.59 Weighted Avg. (Open Space& Roof), HSG "D", Slope Range 0-2%; <br /> I = 8.1 in/hr per Madison rainfall intensity; <br /> A= 0.15 acres; <br /> *The rational method runoff coefficients and rainfall intensity were determined using the <br /> Wisconsin Department of Transportation Facilities Development Manual Procedure 13-10-5 <br /> Figures 2 and 4. <br /> Designed By: AFF <br /> Date: 5/26/2015 <br /> Checked By: <br /> Date: <br /> Stormwater Submittal <br /> PC-03-15 <br /> 5/26/2015 Exhibit#3-4 <br />