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average of 4,327 mg/1 in 1996. Average TDS levels over the previous five-yeaz <br />permit term were 3,247 mg/1. Concentrations of sulfate, calcium, and magnesium <br />have increased in similar proportion, while sodium and bicarbonate concentrations <br />have decreased. <br />Bond Creek <br />Mining in the Bond Creek drainage began in 1988. Data obtained at the outfall of <br />Pond 008 show an increase in flows in Bond Creek over the last nine years. Mean <br />annual flow in 1987 was .028 cfs, and in 1996 was 0.479 cfs. Concentrations of <br />total dissolved solids have increased steadily during the past five years, from 1,367 <br />mg/1 1991 to 2,927 mg/l 1996. <br />Fish Creek is monitored at site SW-S2-13, downstream of the confluences of Bond <br />Creek and Cow Camp Creek with Fish Creek. Data from the site does not show any <br />identifiable change in water quality or quantity when compared with Fish Creek site <br />SW-S2-11, upstream of Bond Creek and Cow Camp Creek. <br />Effects of Minine on Surface Water <br />Changes in the quantity of water to the prevailing hydrologic balance are primazily <br />due to the location and timing of flows. It is difficult to define any changes due to <br />mining in the Grassy Creek basin because baseline data collected in 1980 include the <br />influence of 12 years of previous mining activity at Seneca II Mine. The Fish Creek <br />drainage, however, does indicate a change in the ground and surface water systems. <br />Mining has increased [he amount of ground water available to be dischazged into the <br />surface water system, due to discharging spoil aquifers. Cow Camp Creek now <br />exhibits perennial stream flow as a result of mining in this drainage whereas prior to <br />mining the creek ephemeral stream flow conditions existed. <br />Data are insufficient to demonstrate whether short term decreases in stream flow are <br />due to initial filling of ponds and resaturation of backfilled spoils. However, it is <br />apparent that any depletion is extremely short-lived. Variability in annual amounts <br />of precipitation supplied to the watershed makes it difficult to assess short term <br />changes; however, long-term changes in flow aze expected to be minimal. <br />Three primary impacts on surface ~ pater quality were identified: 1) increased erosion <br />and sediment yield; 2) exceedences of applicable water quality standards; and, 3) <br />increased total dissolved solids loading. <br />z~ <br />