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Mineral Joe Mine - Drainage Design Plan 38 <br />Results indicate that the existing MDS, LDS -E, and LDS -N diversion structures are capable of conveying <br />the 100 -year 24 -hour storm with an average velocity of less than the design criteria of 7 ft/sec. The average <br />calculated velocity for the MDS, LDS -E, and LDS -N profiles was 3.20 ft/sec and the maximum calculated <br />velocity was 5.79 ft/sec (Table 20). <br />As currently constructed, the UDS is incapable of conveying the 100 -year 24 -hour storm with an average <br />velocity of less than 7 ft/sec. The calculated flow velocities, based on local bed slopes and an assumed D84 <br />grain size of 25 mm, range from 7.4 to 16.3 ft/sec (Table 21). A stability analysis was conducted to <br />determine the D84 grain size necessary to impede flow velocities and prevent scour, based on the existing <br />channel geometries (side slope ratio and bed slope). The required rock size would range from 127 to 330 <br />mm (5 to 13 inches) for the surveyed segments, based on the existing channel slopes (Table 21). <br />The UDS channel has been redesigned with shallower side slopes (3:1), a shallower local bed slope, and six <br />check/drop structures to dissipate grade and energy. The allowable bed slope for the D84 grain size of 25 <br />mm is 0.035 ft/ft. This slope will be graded into native material between the drop structures, as shown in <br />Plate 3. The drop structures will be constructed with 4:1 bed slopes and will be constructed with a 2 -ft <br />vertical drop (DS -1, DS -2) or a 3.5 -ft vertical drop (DS -3, DS -4, DS -5, and DS -6) over a span of 8 to 14 <br />feet. Channel scour analysis, based on the Thorne and Zevenbergen (1985) resistance equations, indicates <br />that a D84 grain size of 406 mm (16 inches) would be required to keep flow velocities below 7 ft/sec during <br />peak flows of the 100 -yr 24 -hr storm. The planned channel design is shown in Plate 3 and the calculated <br />flow velocities, channel stage, and shear stress are summarized in Table 21. <br />Table 21. Stage, Velocity, and Shear Stress for 100 -year Peak Flow for the Existing and <br />Planned UDS <br />Diversion <br />Q100 <br />D. <br />Stage <br />Area <br />Perimeter <br />Width <br />R <br />Hydraulic <br />Slope <br />n <br />Vavg <br />Q <br />Shear <br />Froude <br />Structure <br />Radius <br />(cfs) <br />(mm) <br />(ft) <br />(sq ft) <br />(ft) <br />(ft) <br />(ft) <br />(ft) <br />Oft) <br />(ft's) <br />(cfs) <br />(Psf) <br />UDS-PI <br />62.40 <br />25 <br />0.7 <br />5.38 <br />11.54 <br />11.32 <br />0.47 <br />0.47 <br />01008 <br />0.031 <br />9.06 <br />48.69 <br />2.93 <br />2.3157 <br />0.8 <br />6.54 <br />12.16 <br />11.9 <br />0.54 <br />055 <br />0.1008 <br />0.031 <br />10.18 <br />6657 <br />3.38 <br />24210 <br />UDS -P2 <br />6240 <br />25 <br />1.1 <br />7.08 <br />11.9 <br />11.43 <br />06 <br />0.62 <br />00434 <br />0.03 <br />741 <br />52.43 <br />161 <br />1.6586 <br />1.2 <br />8.25 <br />125 <br />12 <br />0.66 <br />069 <br />0.0434 <br />0 029 <br />803 <br />6625 <br />1.79 <br />17063 <br />UDS -P3 <br />62.40 <br />25 <br />1.4 <br />6.4 <br />7.99 <br />731 <br />0.8 <br />088 <br />0.0375 <br />0 029 <br />8.66 <br />55.46 <br />1.88 <br />16302 <br />1.5 <br />7.16 <br />8.59 <br />786 <br />0.83 <br />091 <br />0.0375 <br />0 029 <br />8.95 <br />64 13 <br />1.95 <br />16530 <br />UDS -P4 <br />62.40 <br />25 <br />1.3 <br />5.18 <br />6.66 <br />576 <br />0.78 <br />0.90 <br />00666 <br />0.029 <br />1122 <br />58.12 <br />323 <br />2.0853 <br />14 <br />5.76 <br />692 <br />5.9 <br />0.83 <br />098 <br />00666 <br />0.029 <br />11 85 <br />68.25 <br />346 <br />2.1129 <br />UDS -P5 <br />6240 <br />25 <br />1 1 <br />4.43 <br />627 <br />555 <br />0.71 <br />0.80 <br />0.1027 <br />0.029 <br />12.85 <br />5692 <br />4.53 <br />25341 <br />1.2 <br />5.00 <br />6.58 <br />5.78 <br />076 <br />086 <br />0.1027 <br />0 029 <br />13.62 <br />6807 <br />4.87 <br />2.5817 <br />UDS -P6 <br />62.40 <br />25 <br />1.9 <br />5.12 <br />6.11 <br />4.67 <br />0.84 <br />1.10 <br />00633 <br />0 028 <br />11.91 <br />61 <br />3.31 <br />20053 <br />2.0 <br />5.60 <br />638 <br />4.86 <br />0.88 <br />1.15 <br />0.0633 <br />0 028 <br />12.34 <br />6907 <br />3.46 <br />20253 <br />UDS -P7 <br />62.40 <br />25 <br />15 <br />4.30 <br />5.71 <br />471 <br />0.75 <br />091 <br />0.1003 <br />0.029 <br />13.65 <br />58.68 <br />471 <br />25155 <br />1.6 <br />4.78 <br />602 <br />4.94 <br />0.79 <br />097 <br />0.1003 <br />0 028 <br />14.24 <br />68.11 <br />4.97 <br />25505 <br />UDS -P8 <br />6240 <br />25 <br />1.4 <br />3.52 <br />502 <br />3.88 <br />0.7 <br />091 <br />0.1458 <br />0.029 <br />1557 <br />5478 <br />6.38 <br />28807 <br />1 5 <br />3.91 <br />528 <br />406 <br />0.74 <br />0.97 <br />0 1458 <br />0.029 <br />1627 <br />63.71 <br />674 <br />2.9186 <br />UDS-PI <br />62.40 <br />127 <br />10 <br />9.03 <br />13.39 <br />1306 <br />067 <br />069 <br />0.1008 <br />0.057 <br />635 <br />57.39 <br />4.24 <br />1.1 <br />10.37 <br />13.99 <br />13.62 <br />0.74 <br />076 <br />0.1008 <br />0.055 <br />7.02 <br />7275 <br />466 <br />UDS -P2 <br />62.40 <br />127 <br />14 <br />10.76 <br />13.72 <br />13 13 <br />078 <br />0.82 <br />00434 <br />0.052 <br />503 <br />54.15 <br />2.13 <br />1 5 <br />12.11 <br />14.62 <br />14 <br />083 <br />0.87 <br />0.0434 <br />0 051 <br />532 <br />64.47 <br />224 <br />UDS -P3 <br />6240 <br />127 <br />1 8 <br />977 <br />10.38 <br />9.52 <br />094 <br />1.03 <br />00375 <br />0 049 <br />565 <br />55.18 <br />2.2 <br />1 9 <br />10.75 <br />10.98 <br />1008 <br />098 <br />1.07 <br />00375 <br />0 048 <br />5 88 <br />63 19 <br />2.29 <br />UDS -P4 <br />62.40 <br />203 <br />19 <br />8.89 <br />821 <br />6.63 <br />1.08 <br />1 34 <br />0.0666 <br />006 <br />676 <br />60.1 <br />45 <br />20 <br />9.56 <br />8.46 <br />677 <br />1.13 <br />1.41 <br />00666 <br />0.059 <br />7.07 <br />67.62 <br />47 <br />UDS -P5 <br />62.40 <br />279 <br />1 8 <br />8.79 <br />8.17 <br />6.81 <br />1.08 <br />1.29 <br />01027 <br />0.074 <br />68 <br />59.72 <br />689 <br />19 <br />9.48 <br />8.45 <br />7 <br />1.12 <br />135 <br />0.1027 <br />0.072 <br />715 <br />67.77 <br />718 <br />UDS -P6 <br />62.40 <br />254 <br />27 <br />9.45 <br />83 <br />614 <br />1.14 <br />1 54 <br />00633 <br />0.063 <br />646 <br />61.02 <br />45 <br />28 <br />10.07 <br />8.57 <br />6.33 <br />1 18 <br />1.59 <br />00633 <br />0.062 <br />669 <br />67.33 <br />4.64 <br />UDS -P7 <br />62.40 <br />330 <br />2.3 <br />8.77 <br />7.9 <br />606 <br />1 11 <br />1.45 <br />0 105 <br />0 078 <br />6.66 <br />58.43 <br />728 <br />24 <br />9.39 <br />8.14 <br />619 <br />1.15 <br />1.52 <br />0 105 <br />0 076 <br />697 <br />65.42 <br />755 <br />4148B.131029 Whetstone Associates <br />