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<br />The rated discharge for the trial ditch using Manning's Equation: <br />The properties of a 1-ft-deep, 2:1 side slope V-ditch: <br />A=2ft' <br />P = 4.47 ft <br />R = 0.447 ft <br />The slope of Ditch D-4 is 0.01% <br />Q = (1.486/n) A R Z" S "Z <br />Q = (1.486/0.025) (2ft')(0.447 ft)~" (0.01)"Z <br />Q=6.95 cfs <br />6.95 cfs > 3.63 cfs, Q ditch > Q drainage, trial ditch is adequate <br />Culvert C-1 <br />Trial configuration - 30-in-diameter CSP, 5=0.015% <br />Overland flow time for Area 9 (0.90 acre), which contributes to Culvert C-1, is 19 min, <br />from the Yarnell Figure H. <br />The total flow time =overland = 19 min <br />Rainfall intensity: <br />For Region 6 <br />I =(210)/(19 + 26) = 4.47 in/hr <br />For Region 7 <br />I =(77)/(19+10) = 2.66 in/hr <br />I average = 3.67 in/hr <br />The discharge for Area 9 using the Rational Formula: <br />Q = (0.50) (3.67 in/hr) (0.90 acre) = 1.65 cfs <br />Since Culvert C-1 also collects discharge from Ditches D-1, D-2, D-3, and D-4, total flow <br />Q =1.75 cfs + 5.35 cfs + 1.31 cfs + 3.63 cfs + 1.65 cfs =13.69 cfs <br />The rated discharge for the trial ditch using Manning's Equation: <br />The properties of a 30-in-diameter circular pipe flowing 90% full <br />A=BrZ-'h r2(M-sinM) <br />Where M = 2 (azc cos (r-z)/r) = 2 (arc cos (15-3)/15) = 73.74 <br />73.74 degrees =1.29 radians <br />A = B (15)' -'fi (15)Z(1.29 -sin (73.74)) = 743.65 in Z = 4.66 ftZ <br />Wetted perimeter, P = B d - (B r M)/(180) = 6.25 ft <br />6 <br />Summary of Kvaemer Glculations <br />Piceance SiM Diversion Ditch System <br />Technical Revision Mi'ung and RecJamaiion Pemut <br />