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_ , rr ... • The baseline water quantity and qua.(ity r~m~nitor.imr plnn complier! with rcyulation 2.04.7 and was sufficient to delineate d.istinct.ions between runoff from unmined and mined land. The latter data can be used to predict possible impacts to Trout Creek and Oak Creek fmm proposed mining. A previous study done by McWhorter, 1975, indicated that the depth of runoff from the southern portion of the mine, which in- cluded mined land, was approximately .94 feet per acre. Extrapolating this to the proposed Moffat area of depth runoff, there is expected to be approximately .4 feet (p. 2.5-14 of the permit application). h'ith 2945 acres in the southern portion of the mine and 1030 in the Moffat area, annual runoff contributions from the mine site should be approximately 1720 acre-feet per year, which is barely five percent of the Trout Creek watershed yield. Post-mining spoil water was investigated during the baseline program and was found to contain a total dissolved solids concentrations of approximately 3000 mg/1. Since the mine is onlu contributing approximately 5 percent of the mean annual c.•atershed yield, the resulting increase in the man annual concentration of TDS in Trout Creek after .mining in the hlo ffat area is predicted to be 12 mg/1 from a baseline value of 199 mq/1 to 196 mg/1 (p. 2.5-99 through 7.5-I03 of the permit application). This appears to be an i.nsicmificant increase. Water Rights and Replacement (2.04.7(3), 2.05.6, 2.07.6, 4.05.15) Water rights have been appropriated for the Edna mine, and can be used to replace any supplies that are contaminated, disrupted, or interrupted by mining activities. There are nineteen available ranter n yhts Iisted on p. 4.6-62 of the permit applica- tion. These ditches will he used to replace any impacted supply with an equivalent type supply for irrigation, domestic, and stock, water needs. Ideally, water fot use in the mine will be pumped Erom pit inflow when sufficient quantities are avail- able. In the Nest Rigde area, suuplemcntal water is dcno;n From ttao withdrawal points on Trout Creek. When mining progresses to the aloCfat .~rca, a canter withdrawal site wi 11 be provided along Trout Creek to prevent ~r rlditional impacts (p. 3.7-13 and Exhibit 1.0-1 of Chc pc emit anl,li c.,Ci nn). R~3 c~.~i vin:i Strcom Stanrl. u-ds 'fJ!'Di;S Reg ui re men is Point source discharges from the Edna mine an ter tan separate receiving streams, Trout Creek and Oak Creek. Both streams h.we been classified by the Colorado Depart- ment of Health, f:'ater [iuality Control Division, as Class k1 - Recreation, Aquatic Life Class #1 - Cold [:'ater, hater Supply, and Agricultural Gse. These standards set numerica_' units on ehysical, biological, inorganic, and metal discharges to the receiving streams. ict present, the enforcerr_nt of these standards are handled by the Colorado Department of health, fdOCD, under Pittsburg and Midway's NPDES permit number CO-0032634.