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r <br />L J <br />1486wY <br />0.294 ifs <br />1985 CY (Calendar Year) = 0.357 cfs <br />1984CY = 0.447 cfs <br />1983CY = 0.154 cfs (reservoir did not completely fill until <br />March 7, 1983) <br />Review of hydro9raphs and the above table shows that flow the past four years has been <br />lower than previously measured. This is largely due to relatively lower annual <br />precipitation during this period. Also affecting flow from the 004 pond fs the reduced <br />diameter of the discharge culvert modified on May 29, 1987 (36 inches to 6 inches). <br />Review of Table 18 (Appendix A) sh ous the water at this site to be a MgC a-S04 type. TDS <br />has consistently increased since 1982 primarily due to an increase in upgradient mined <br />area and ground water resaturation in the spoils. Also responsible for the increase in <br />TDS in 1987 th rough 1990 is the decreased spring snowmelt runoff for this period as <br />compared to 1984 through 7986. Reduced runoff and subsequent evaporation during the <br />summer tends to concentrate dissolved solids, resulting in increased TDS over time. <br />surface water Site Sw-52-6. This site monitors Cow Camp Creek less than 1/4 mile <br />downstream of the NPDES 004 discharge and an adjacent diversion ditch. Review of a <br />hydrograph consisting of all data from May, 1981 to September, 1990 shows that spring <br />runoff has been lower than normal the last four years. Peak flows at this site have been <br />reduced further by the reduction of discharge culvert diameter in 1987 at the NPDES 004 <br />site discussed earlier. <br />Review of Table 20 (Appendix A) shows that Site 6 displays a MgC x-504 type water. TDS <br />values have increased every year as a result of the 7DS increases noticed at the MPDES 004 <br />site caused by spoils water discharges and, to a lessor extent, reduced runoff and <br />subsequent evaporation. <br />Surface 4la ter SiCe SU-S2-10. The site was instituted in May, 1987, and monitors Cou Camp <br />Creek at its confluence with Fish Creek. It is monitored May through September on a <br />monthly basis. As was suspected by PCC staff before initiating monitoring, this site <br />flows less often than the upper Cow Camp Creek, Site 6. Flow was observed only for the <br />May monthly visit, while Site 6 floes year round. Flow at this site was 31 percent less <br />than that of Site 6 in May due [o stream channel infiltration and the absence of lateral <br />13 <br />