Laserfiche WebLink
<br />this annual deposition of sand and gravel that Sandco, <br />Inc., proposes to remove from the river channel by <br />selectively restricting the mining operation to the most <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 caoacity, and an <br />increased probability of flooding due to aggradation of the <br />streambed. Maintenance of the natural channel capacity in <br />this manner reduces the flood stage that would otherwise be <br />created by aggradation. The extraction of sedirt~ent from <br />the most elevated sand and gravel deposits will coincide <br />witk~ the seasonal periods of low water flow that typically <br />occur during late fall, winter and early spring months in <br />the Animas River. Because the low water cycles vary due to <br />weather variation, mining 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 />lo~a water flow. <br />Because this controlled mining of the sand and gravel <br />deposits does not increase the existing channel bank <br />heights, accelerated erosion thereto will not or_cur. <br />Further, since the streambed will not he excavated below <br />the low water .ievel of the river, streambed degradation due <br />to induced headcutting will not occur and no detrimental <br />2 <br />