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-18- VII. Alluvial Valley Floors - Rules 2.06.8 and 4,24 The proposed permit area for the Munger Canyon Mine occupies parts of four drainage basins distinguishable on a topographic map. These basins include Munger Canyon, Stove Canyon, Buniger Canyon and an unnamed tributary to East Salt Creek, just south of Munger Canyon. Stove Canyon and Buniger Canyon are sub-basins within the aig Salt Wash drainage system. Munger Canyon and the unnamed tributary are both sub-basins of the East Salt Creek drainage. The only planned surface disturbance related to the mine will occur within Munger Canyon. Development of mine workings will extend under portions of all the above-mentioned drainage basins during this 5-year permit term. East Salt Creek has been determined to be an alluvial valley floor. The irrigated agriculture which exists in the East. Salt Creek Valley is evidence of this conclusion. The only physical disturbance existing on this alluvial valley floor is the haul road to the mine portals. This is a farm road which existed prior to the operation which was improved slightly for the operation. Unconsolidated alluvial deposits were mapped by the applicant in the lower reaches of Munger Canyon. The proposed waste pile and associated features are located at the edge of these deposits. Exploratory drilling in the Munger Canyon alluvium by the applicant indicates that ground water is greater than 40 feet below the surface of the valley floor. Also, the absence of mottling in test pits TP-1, TP-2 and TP-3 indicate the Lack of natural subirrigation in the Munger Creek alluvium. Mean annua3 discharges in Munger Canyon were estimated by the applicant to range from 0.02 cfs to 0.48 cfs, with an average of 0.17 cfs. Mean monthly flows were estimated at 0 during winter months and 1 cfs maximum in May. Flow in Munger Creek occurs mainly in response to snowmelt and storm events. The Division has determined that Munger Canyon does not include an alluvial valley floor. The depth to ground water precludes subirrigation and surface water flows are prohibitively Iow for use in successful irrigated agriculture without a means of retaining the flows. Salt Creek Mining Company has not supplied information with respect to the presence of an alluvial valley floor in the aig Salt wash, or information on its tributaries, Stove Canyon and Buniger Canyon. Therefore, for the purpose of this Findings Document, the Division will assure the worst case; that there is a potential alluvial valley floor in the Big Salt Wash. The following analysis will consider potential effects of the operation under this assumption. The Loma loadout occupies a rail siding along the D&RGW Railroad right-of-way near the town of Loma, Colorado. This rail siding existed prior to the Zoad- out, and was historically used as a loading site for sugar beets. The total disturbed area at the loadout is 5.6 acres.