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<br />Ditch D-7 <br />Trial configuration - V-ditch, 1-ft-deep, 2:1 side slope, unlined, assumed velocity = 3 fps <br />Overland flow time for Area 7 (1.02 acres), which contributes to Ditch D-7, is 12 min <br />The ditch flow time: <br />t =length/velocity = 108 ft/[(3 ft/sec) (60 sec/min)] = 0.60 min <br />Total flow time = 12 + 0.60 = 12.6 min <br />Rainfall intensity: <br />For Region 6 <br />I =(210)/(12.6+ 26) = 5.38 in/hr <br />For Region 7 <br />I = (77)/(12.6+10) = 3.41 in/hr <br />I average = 4.40 in/hr <br />The discharge for Area D-1 using the Rational Formula: <br />Q = (0.50) (4.40 in/hr) (1.02 acres) = 2.24 cfs <br />Since Area 0.5 and D-6 also flow into Ditch D-7, the total discharge <br />Q=0.97cfs+2.24cfs+0.90 cfs=4.11 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 ditch is: <br />A =2ft' <br />P=4.47ft <br />R = 0.447 ft <br />The slope of Ditch D-7 is 0.0423% <br />Q = (1.486/n) A R'" S "' <br />Q = (1.486/0.025) (2ft~) (0.447 ft)"' (0.0423)"Z <br />Q = 14.30 cfs <br />14.30 cfs > 4.11 cfs, Q ditch > Q drainage, trial ditch is adequate <br />Ditch D-8 <br />Trial configuration - V-ditch, 1-ft-deep, 2:1 side slope, unlined, assumed velocity = 5.5 <br />fps <br />Overland flow time for Areas 8 (0.80 acre} and R-8 (0.18 acre), which contribute to Ditch <br />0.8, is 13.3 min. <br />The ditch flow time: <br />9 <br />Summary of Kvaemer Calculations <br />Piceance site Diversion Ditch System <br />Technical Revision Mining and Reclamation Permit <br />