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<br />' this annual deposition of sand and gravel that Sandco, <br /> Inc. proposes to remove from the river channel by <br />' the minin <br />r <br />stri <br />tin <br />o <br />er <br />tio <br />l <br />ti <br />l to the most <br /> g <br />g <br />p <br />ec <br />ve <br />y <br />e <br />c <br />a <br />n <br />se <br />' elevated deposits. This method of controlled mining will <br /> contribute to the stability of the river system by <br />' preventing the accumulation of sediment within the channel <br /> with a coexistent decrease in channel capa city, and an <br />' <br /> increased probability of flooding due to aggrad ation of the <br />' streambed. Maintenance of the natural channel capacity in <br /> this manne r reduces the fl ood stage that would otherwise be <br />' created by aggradation. The extraction of sediment from <br /> the most elevated sand and gravel deposits will coincide <br />' ith th l <br />i <br />d of low water flow that t <br />icall <br /> e <br />w seasona <br />per <br />o <br />s yp <br />y <br /> occur duri ng late fall, winter and early spring months in <br /> the Animas River. Because the low water cycles vary due to <br /> weather variation, mi ning operations must vary <br /> accordingly . Excavations will not extend below the water <br />' level of the river, and the volume of material removed is <br />' thus limited to that annually deposited above the level of <br />low water flow. <br />1 <br /> Because this controlled mining of the sand and gravel <br />' deposits does not increase the existing channel bank <br />' heights, accelerated erosion the reto will not occur. <br /> Further, since the streambed will not be excavated below <br />' ttie low water level of the river, st reambed degradation due <br /> to induced headcutting will not occur and no detrimental <br />' 2 <br /> <br />