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CESPK-CO-R Public Notice Number 1994 The extraction of sediment coincides with the seasonal periods of low water flow that occur during late fall, winter, and early spring. Typical mining operations include the construction of an alluvial berm approximately 1.50 feet high along the contour of the sand baz at the low waters' edge to prevent disturbed sediment from entering the river. Once excavation is completed, the sand between the berm and the bank is removed with a rubber tired front end loader or excavator and placed in trucks or other hauling equipment and transported from the site. Excavated materials, which range between sand and silt particle size, aze usually hauled up to the Dalton Pit (also owned by the applicant) for processing, if necessary. Upon completion of the mining each year, the surface is dressed and left in a smooth configuration. The applicant states "... This method of controlled mining contributes to the stability of the river system by preventing the accumulation of sediment on the point bar, thereby decreasing the pressure of the rivers flow on the east bank with a corresponding decrease in erosion of the east bank. Additionally, this method of mining does not increase the existing channel bank heights and so does not contribute to accelerated bank erosion and no detrimental impacts to local or off-site areas have been observed nor aze expected. Further, this type of mining operation does not involve the removal of existing riparian vegetation or the alluvial soil overburden." ALTERNATIVES: The no action alternative would result in permit denial and essentially -require the-instream-mining operation-to-cease..This_alternative_would~nssibly_result in_the . _ _ _ applicant mining other areas within their permit boundaries. While mining upland azeas would avoid excavation activities within the Animas River, these azeas provide a finite and nonreplenishable source of material and can result in additional or different types of negative impacts. Impacts may include the loss of riparian vegetation, interception and exposition of ground water, and an increased number of other mine locations and associated secondary impacts (such as habitat loss, bank destabilization, loss of flood control function, noise, traffic, dust and visual aesthetics. Alternative methods of mining or other mining locations have not been identified by the applicant; however, six additional instream sand and gravel mining activities occur in the Animas River valley (refer to "Additional Information" section below). AREA DESCRIPTION: The project site is located two miles north of Durango on a point bar on the southwest bank of the Animas River. At this location, the Animas River is at an elevation of approximately 6,548 feet msl. The river's drainage basin is approximately 658 square miles and the average annual bankfull dischazge is approximately 4,267 cubic feet per second (cfs). High flows usually occur in the spring between the months of April through July, but can also peak from late summer and fall high intensity thunderstorms. A record 25,000 cfs flow occurred on October 5, 1911, as measured at the USGS stream gage located in Durango. •