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the lower Cow Camp Creek Site 10, this site flows less often than the upper Bond Creek • <br />site, NPDES 008. Flow was observed a[ Site 12 only during the May and June visits, white <br />NPDES 008 flows continuously. This flow decrease is due to evapotranspiration and <br />infiltration losses. <br />Pater at Site 12 during 1993 was a MgOaN a-S04 type (Table 16). The 1993 average TDS value <br />of 1611 mg/t falls within the historic range. <br />Surface Hater Site SY-52.11. This site monitors Fish Creek upstream of its confluence of <br />Cow Camp Creek. It is monitored May through September on a monthly basis and only if <br />either Sites 10 or 12 are flowing. Hater at this site is a CaM g-HC03SO4 type. This site <br />is upstream of Seneca II Mine discharges; therefore, its water chemistry is primarily the <br />result of natural or background conditions. <br />Surface Pater Site SN-S2-13. This site was instituted in May 1987 and monitors Fish Creek <br />downstream of its confluence with Bond Creek. It is monitored May through September on a <br />monthly basis end only if either Sites 10 or 12 ere flowing. Hater at this site in 1993 <br />is a CeMg-HC0350` type. The increases in TDS values from Site 11 to Site 13 were only 18 <br />percent in May and 13 percent in June. <br />To summarize water quality in the Fish Creek basin, it appears Chet the Seneca 11 Mine has <br />little impact on Fish Creek. Hater discharged from the mine is Lost to stock ponds, <br />evapotranspiration, and the alluvium as it flows through Twentymile Park. Dissolved <br />solids from mine discharges are diluted during the snowmelt runoff in March and April <br />(prior [o Che irrigation season) by high stream tl ows with relatively !ow TDS <br />concentrations. The natural conditions in Twentymile Park appear to have a much greater <br />impact on the water quality of Fish Creek. As a final note, the irrigation ditch that <br />diverts water from Fish Creek just upstream of the confluence with Bond Creek was observed <br />to be flowing only during the July visit this year. <br />Little Grassy Creek Drainaoe. Two monitoring sites lie within [he Little Grassy Creek <br />drainage: Surface Water~5ite SN-52-5, located in the southwest portion of the permit area <br />and NPDES Discharge Point 002, also known as [he wedge Impoundment. <br />Surface Water Site SW-52-5. Surface Hater Site SW-S2-5 drains the upper reaches of Little <br />Grassy Creek which are undisturbed by mining. Review of the hydrograph of monthly flow <br />12 <br />