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2. The surface coal mining operations would not materially damage [he quantity and <br />quality of water in surface and undergroundwater 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 208 <br />acre-ft/yr in 1978 is less than one percent of the mean annual flow in the North <br />Fork of the Gunnison River. Surface flow supplied to [he alluvial valley floor <br />along the North Fork comes primarily from areas upstream from the permit area <br />and this flow is regulated by Paonia Reservoir which is located approximately six <br />miles upstream of the alluvial valley floor. Mining operations require <br />approximately 150 acre-feet of fresh water per year for sanitary and drinking <br />water. This water is withdrawn from the North Fork during spring runoff when <br />water rights are available and used throughout the year. The wastewater is then <br />treated and returned [o the hydrologic system through periodic discharges from <br />[he waste water treatment plant. This results in negligible loss to [he 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 [o assure <br />compliance with water quality standards. As a result, no degradation in the <br />quality of surface waters supplied to the alluvial valley floor is anticipated. <br />Any groundwater supplied from strata with the potential to be affected by the <br />proposed operations is minimal. No major aquifers have been identified in either <br />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 springs <br />in or adjacent to the five year permit area are located along Sylvester Gulch. <br />Since part of this watershed would be subject to subsidence, some of these <br />springs could dry up. However, these springs, which supply less than 50 percent <br />of the flow in Sylvester Gulch, are currently used as a water source for the Tony <br />Bear Pipeline which is now owned by MCC. Loss of this water would not <br />significantly decrease the water supply to the alluvial valley floor. <br />No significant degradation in groundwater 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, [he 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 />57 <br />