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on a monthly basis. This year, flow was present at this site only <br />during the May and June visits, although NPDES 008 upstream was flowing <br />almost continuously. This reduction in flow is due to stream channel <br />infiltration and evapotranspiration. The TDS plot indicates a slightly <br />increasing trend. <br /> <br />I <br />- Surface Water Site SW-S2-11 (SSF11). This site monitors Fish Creek <br />upstream of its confluence of Cow Camp Creek. It is required to be <br />monitored May through September on a monthly basis, but only if either <br />Sites 10 or 12 are flowing. However, field parameters and flow <br />estimates may sometimes be provided voluntarily when not required. This <br />site is upstream of Seneca II Mine discharges. <br />- Surface Water Site SW-52-13 (SSF13). This site monitors Fish Creek <br />downstream of its confluences with Cow Camp Creek and Bond Creek. It is <br />monitored at the same frequency as Site 11. The increase in TDS values, <br />from Site 11 to Site 13, was from 240 to 240 mg/1 (0~ increase) in May, <br />and from 510 to 540 mg/1 (6$ increase) in June. <br />On Page 7-247 of the Seneca II Mine Probable Hydrologic Consequences <br />(PHC), predictions were made for the TDS increases to be observed on <br />Fish Creek during the months of June and July due to discharges from the <br />Seneca II Mine. In June, an increase from 421 to 497 mg/1 (18~) is <br />predicted. In July, an increase from 533 to 607 mg/1 (13$) is <br />predicted. Neither lower Bond Creek nor lower Cow Camp Creek was <br />flowing in July this year. As stated in the previous paragraph, only a <br />6$ increase in TDS was noted between the two sites in June. It appears <br />that the Seneca II Mine has little impact on Fish Creek. Water <br />discharged from the mine is lost to stock ponds, evapotranspiration, and <br />the alluvium as it flows through Twentymile Park. Dissolved solids from <br />mine discharges are diluted during the snowmelt runoff in March and <br />April (prior to the irrigation season) by high stream flows with <br />relatively low TDS concentrations. The natural conditions in Twentymile <br />Park appear to have a much greater impact on the water quality of Fish <br />Creek. <br />15 <br />