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<br />Ditch D-1 <br />Trial configuration - V-ditch, 1-ft-deep, 2:1 side slopes, unlined, assumed velocity = 7 <br />fps <br />Overland flow to ditch D-1 will be runoff from Areas 1 (0.62 acre) and R-1 (0.11 acre). <br />Overland flow time for the area contributing to Ditch D-1 is 13.3 min, from the Yarnell <br />Figure H. <br />The ditch flow time: <br />t =length/velocity = 290 ft/[(7 ft/sec) (60 sec/min)] = 0.70 min <br />Total flow time =overland + ditch = 13.30 + 0.70 = 14 min <br />Rainfall intensity: <br />For Region 6 <br />I =(210)/(14 + 26) = 5.25 in/hr <br />For Region 7 <br />I =(77)/(14+10) = 3.21 in/hr <br />I average = 4.23 in/hr <br />The discharge for Areas 1 and R-1 using the Rational Formula: <br />Q = (0.50) (4.23 in/hr) (0.62 acre) + (0.95) (4.23 in/hr) (0.11) = 1.75 cfs <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 />Area,A=bh=(2ft)(lft)=2ft <br />Wetted perimeter, P = 2 (1~ + 22)05 = 4.47 ft <br />Hydraulic radius, R = A/P = 2 ft'/4.47 ft = 0.447 ft <br />Slope of Ditch D-1 is 0.0377% <br />Q = (1.486/n) A R 2" S'~' <br />Q = (1.486/0.025) (2ft') (0.447 ft)"' (0.0377)"Z <br />Q = 13.50 cfs <br />13.50 cfs > 1.75 cfs, Q ditch > Q drainage, trial ditch is adequate <br />Ditch D-2 <br />Trial configuration -trapezoidal ditch, 1.5-ft-deep, 2:1 side slope, 2-ft-wide bottom, <br />unlined, assumed velocity = 3.3 fps <br />Overland flow time for Area 2 (3.08 acres), which contributes to Ditch D-2, is 19.6 min, <br />from the Yarnell Figure H. <br />3 <br />Summary of Kvaemer Calculations <br />Piceance Site Diversion Ditch System <br />TerJvtical Revision Muting and Reclamation Pemtit <br />