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<br />6. The pond must be "inspected during construction under the supervision of, <br />and certified after construction by, a qualified registered professional <br />engineer. Certification of the constructed pond shall be forwarded to the <br />Division immediately following construction "(Rule 4.05.6(7). <br />7. No designs were provided for the proposed east or west drainage channel <br />diversions. I have made a rough estimate of the drainage area length and <br />change in elevation for the west channel from a USGS topo map. This should be <br />acceptable, however, the operator should compare the channel design to the <br />existing channel. <br />L = 1730' <br />Z = 7730-7360 = 370' <br />S = 21.4% <br />A = 15 acres <br />10 yr. - 24 hr. rainfall = 2.1" <br />CN = 73 <br />Runoff = 0.37" <br />Slope length = 209(A)•6 <br />A = 33.87 <br />Slope Adjustment = 1.04 <br />Q peak = 21 CFS/in x 0.37" x 1.04 x 15/33.87 = 3.58 CFS <br />Design a channel to handle these flows. <br />L = 520' <br />Z = 60' <br />S = 11.5% <br />Q = 3.58 CFS <br />V = Q/A = 5.7 FPS <br />N = 0.03 <br />K' = QN/b8/3 S1/2 D/b = .125 <br />K' = 0.05 D = .25 <br />The same channel design used for the channel into the sediment pond can be <br />used for this channel. <br />The east channel will carry less flow than the west channel since the west <br />channel will be used to divert the stream channel. For simplicity, it would <br />probably be easiest just to build the east channel to the same design as the <br />west channel and pond channel. <br />8. The drainage control map shows the east channel crossing an access road. <br />How will this be accomplished? If possible, the channel could run along the <br />road to the meadow. If this is not possible then a swale could be constructed <br />in the road since flows in this channel will be low. <br />/vj r <br />7960E <br />