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2. The surface coal mining operations would not materially damage the quantity <br /> and quality of water in surface and underground water systems that supply those <br /> alluvial valley floors or portions of alluvial valley floors (Rule 2.06.8(5)). <br /> All of the surface flow from the permit area drains to the North Fork of the <br /> Gunnison. The applicant has monitored the largest two drainages crossing the <br /> permit area. During this period, Lone Pine Gulch has experienced no flow. <br /> Sylvester Gulch has experienced ephemeral stream flow. The record yield of <br /> 208 acre-fUyr in 1978 is less than one percent of the mean annual flow in the <br /> North Fork of the Gunnison River. Surface flow supplied to the alluvial valley <br /> floor along the North Fork comes primarily from areas upstream from the <br /> permit area and this flow is regulated by Paonia Reservoir which is located <br /> approximately six miles upstream of the alluvial valley floor. Mining <br /> operations require approximately 150 acre-feet of fresh water per year for <br /> sanitary and drinking water. This water is withdrawn from the North Fork <br /> during spt:ng runoff when water rights are available and used throughout the <br /> year. The wastewater is then treated and returned to the hydrologic system <br /> through periodic discharges from the waste water treatment plant. This results <br /> in negligible loss to the system. <br /> The applicant's discussion of probable hydrologic consequences identified no <br /> anticipated changes in surface water quality. All runoff from disturbed surface <br /> areas, including runoff from the refuse disposal site, drains through an approved <br /> sediment control system. All discharges are made under the conditions of the <br /> applicant's NPDES permit, and any effluent must meet the water quality <br /> standards for the receiving streams. If necessary, discharges are treated to <br /> assure compliance with water quality standards. As a result, no degradation in <br /> the quality of surface waters supplied to the alluvial valley floor is anticipated. <br /> Any ground water supplied from strata with the potential to be affected by the <br /> proposed operations is minimal. No major aquifers have been identified in <br /> either the coal seam or the overburden. Springs in the area are associated with <br /> lenticular sands, local faulting and fracturing, and landslides. Most of the <br /> springs in or adjacent to the five year permit area are located along Sylvester <br /> Gulch. S;-ice part of this watershed would be subject to subsidence, some of <br /> these springs could dry up. However, these springs, which supply less than 50 <br /> percent of the flow in Sylvester Gulch, are currently used as a water source for <br /> the Tony Bear Pipeline which is now owned by MCC. Loss of this water <br /> would not significantly decrease the water supply to the alluvial valley floor. <br /> No significant degradation in ground water quality is anticipated. Following <br /> mining, new springs, fed by water supplied by the accumulation of water in the <br /> underground workings, could form. At present, the water quality of these <br /> springs under worst-case assumptions would approximate the water quality of <br /> flooded mine workings at the Oliver Mine adit where total dissolved solids <br /> concentrations range between 1050 and 1900 mg/1 (see CHIS-Affects to Surface <br /> Waters section). However, flow from these springs would be such a minor <br /> 52 <br />