Laserfiche WebLink
FULL BUILD OUT CONFIGURATION <br />Subwatershed information for "H" and "I" ditches found in Volume III, Exhbit E <br />Ditch H-1 <br />Ditch H-1 receives flow from Drainage Area F, Pond F dewatering pump, and local run-off <br />Ditch H-1 exists as a trapezoidal channel, so evaluation for trapezoidal channel will remau <br />Drainage Ditch D -H1 14% Slope Reach <br />Manning's Equation <br />Flow In a Trapezoidal Channel <br />DEPTH <br />D <br />0.300 <br />FEET <br />WIDTH <br />W <br />2.000 <br />FEET <br />Slope <br />S <br />0.140 <br />EXPRESS AS DECIMAL <br />Mannings "N" <br />N <br />0.040 <br />EXPRESS AS DECIMAL <br />SIDE SLOPE <br />X <br />2.000 <br />SLOPE = X:1 <br />AREA=(W*D)+(X*DA2)= <br />0.78 <br />FEET A2 <br />WETTED PERIMETER=(W)+2*[((X*D)A2+DA2)A0.5] <br />334 <br />FEET <br />R=AREA/WETTED PERIMETER <br />023 <br />V=(1 49/N)*(RA.667)*(SA.5)= <br />528 <br />FT/SEC <br />Q=AXV= <br />412 <br />CFS <br />Q REQUIRED - Peak Discharge <br />307 <br />CFS <br />Riprap Sizing - Drainage Ditch D -H1 <br />14% Slope React <br />D50 = Size of Riprap <br />D50 = ((V X SA 17)/7 58))A2 <br />D50 = Diameter in feet <br />V = Velocity <br />S =Slope <br />D50 = <br />0 2 feet <br />3 inches <br />Drainage Ditch D -H1 1% Slope Reach <br />Manning's Equation <br />Flow In a <br />Trapezoidal Channe <br />DEPTH <br />D <br />0500 <br />FEET <br />WIDTH <br />W <br />2000 <br />FEET <br />Slope <br />S <br />0 010 <br />EXPRESS AS DECIMAL <br />Mannings "N" <br />N <br />0.030 <br />EXPRESS AS DECIMAL <br />SIDE SLOPE <br />X <br />2000 <br />SLOPE = X 1 <br />AREA=(W*D)+(X*DA2)= <br />150 <br />FEET A2 <br />WETTED PERIMETER=(W)+2*[((X*D)A2+DA2)A0 5] <br />424 <br />FEET <br />R=AREA/WETTED PERIMETER <br />035 <br />V=(1.49/N)*(RA 667)*(SA 5)= <br />2.49 <br />FT/SEC <br />Q=AXV= <br />3.73 <br />CFS <br />Q REQUIRED - Peak Discharge <br />307 <br />CFS <br />TR -105 Volume XI, App. B-7 09/15 <br />