Laserfiche WebLink
• <br />Rainfall intensity: <br />For Region 6 <br />I =(210)/(18.35 + 26) = 4.73 in/hr <br />For Region 7 <br />I =(77)/(18.35 + 10) = 2.72 in/hr <br />I average = 3.73 in/hr <br />The discharge for Area 3 using the Rational Formula: <br />Q = (0.50) (3.73 in/hr) (0.70 acres) = 1.31 cfs <br />• <br />The rated discharge for the trial ditch using Manning's Equation: <br />The properties of a trapezoidal 1.5-ft-deep, 2:1 side slope, 2-ft-wide bottom ditch: <br />A=7.5ft' <br />P = 8.71 ft <br />R = 0.86 ft <br />The slope of Ditch D-3 is 0.015% <br />Q = (1.486/n) A R'" S "' <br />Q = (1.486/0.025) (7.5ft~)(0.86 ft)~" (0.015)'~Z <br />Q = 49.41 cfs <br />49.41 cfs >1.31 cfs, Q ditch > Q drainage, trial ditch is adequate <br />Ditch D-4 <br />Trial configuration - V-ditch, 1-ft-deep, 2:1 side slopes, unlined, assumed velocity = 5.5 <br />fps <br />Overland flow time for Areas 4 (1.83 acres) and R-4 (0.13 acre), which contribute to <br />Ditch D-4, is 20 min, from the Yarnell Figure H. <br />The ditch flow time: <br />t =length/velocity = 250 ft/[(5.5 ft/sec) (60 sec/min)] = 0.76 min <br />The total flow time = 20 + 1.41 = 20.76 min <br />Rainfall intensity: <br />For Region 6 <br />I =(210)/(20.76 + 26) = 4.49 in/hr <br />For Region 7 <br />I =(77)/(20.76+10) = 2.50 in/hr <br />I average = 3.50 in/hr <br />The discharge for Areas 4 and R-4 using the Rational Formula: <br />Q = (0.50) (3.50 in/hr) (1.83 acres) + (0.95) (3.50 in/hr) (0.13 acre) = 3.63 cfs <br />Summary of Kvaemer Calcvlatlons <br />Piceance Site Diversion Ditch System <br />Teclmial Revision Minvtg and Reclamation Pemtit <br />