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Section 2 <br />Drainage Control Design <br />C7 <br />Table 2-1 100-year Peak Discharqes for the Van 4 Mine Basins <br /> 100- ear peak discharge <br /> Area Calculated Increased by SE <br />Basin ac s -mi cfs cfs <br />1 22.55 0.03523 10.82 19.27 <br />2 3.53 0.00552 2.87 5.12 <br />3 0.70 0.00109 0.90 1.61 <br />2.4 Surface Water Control Structure Design <br />CDM designed one diversion channel to route offsite surface water runoff from Basin <br />1 around the surface mine facilities to the existing drainage located on the north side <br />of the Van 4 Mine. Storm water runoff from Basin 2 will be captured and retained by <br />an earthen berm along the crest of the DRA. Storm water runoff from Basin 3 will also <br />be captured and retained by an earthen berm along the toe of the DRA. <br />2.4.1 Channel Design <br />A diversion channel was designed to convey the 100-year peak discharge from Basin 1 <br />to the existing drainage (refer to Exhibits A and B). CDM used the following <br />equations to calculate the flow velocity and depth in the diversion channel. Input <br />values (listed in Table 2-2) into the equations include 100-year peak discharge, cross <br />section geometry (triangular), slope, and Manning's n value. <br />Q=VA <br />A = (b + zh)h <br />2/3 <br />V = 1.49 (b + zh)h Sv2 <br />n b+2h 1+z2 <br />where: <br />Q = discharge in cfs <br />V = velocity in ft/sec <br />z : 1 = side slope <br />A = flow area in ftz <br />b = bottom width of the cross section in ft <br />h = flow depth in ft <br />S = channel slope in ft/ft <br />n = Manning's roughness coefficient <br />Table 2-2 Input Values for Diversion Channel Capacity Analvsis <br />0 <br />100-yr Q <br />cfs S <br />ft/ft <br />n z <br />ftift b <br />ft <br />19.27 0.0084 0.035 3 0 <br /> <br />2-2 <br />TA64986-Denison Mines\Task Order 1 - Sunday Mines Drainage StudyWan 4 Mine Drainage Study\RepoMVan4 Mine Drainage ReportAm