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Permit C-81-071 1995 Annual Hydrology Report AV-2 wells, adjusted for differences in spring runoff, has not changed since monitoring began in • 1979. The water level data for the Fish Creek alluvial wells do not show any impact from the reclaimed Mine 2 Area. Water Quality The water quality data area summarized in Tables 10 through 15 for the Foidel Creek alluvial wells and Tables 16 through 21 for the Fish Creek alluvial wells. The historic field conductivities for the Foidel Creek wells are plotted on Figure 14, and for the Fish Creek wells on Figure 15. Seasonal variation in conductivity is apparent in the wells. This is probably due to the flushing effect of relatively low dissolved solids surface water that recharges the alluvial aquifers during spring runoff. There was a small increase in the average salt content of the Foidel Creek alluvial groundwater starting in the 1987 water year and continuing through the 1995 water year. This is probably due to the relatively low runoff that persisted from 1987 to 1994. The spike in the conductivity in Well 009-S-10 can not be explained. The water quality in the Foidel Creek alluvial wells show a downstream increase in total dissolved solids and conductivity and change from a sodium-bicarbonate type to a mixed calcium-sodium-bicarbonate sulfate type. The change is apparent in the reach between the 009S-10 well and the 001-S-5 well. This is primarily attributable to recharge of alluvium by Foidel Creek water. Foidel Creek receives sediment pond discharges, containing elevated concentrations of dissolved solids, calcium and sulfate, in the reach of Foidel Creek above the 001-S-5 well. The sediment pond water is largely derived • from spoil runoff and spoil springs. The spoil springs, in particular, are characterized by high sulfate, calcium and dissolved solids concentrations. There is no indication of any significant increase in alluvial groundwater trace metals during 1995. The water quality data for the Fish Creek alluvial wells upstream and downstream of Mine 2 do not indicate any impacts (Figure 15). The 006-AW-2 well, downgradient from the discharge point, does show a higher conductivity during the baseflow period than in previous years related to underground mine discharge. The data does not indicate any significant changes in the trace metals concentrations. The iron and manganese levels in the wells, including the upstream well, are often relatively high. SPOILS Five wells in the spoils are monitored. They are all located at Mine 1 and were installed in 1985 and 1986. Two of these are only monitored for water level. Water Levels The plots of the historic water levels in the spoil wells are presented on Figures 16 through 19. The water levels normally have a similar pattern to the alluvial wells: they respond rapidly to the spring runoff and then decline rapidly in the summer. Wells 026-SP-1 and 026-SP-3 are • sometimes dry by the fall, although this has not happened since 1988. These water levels closely mirror the pattern of the spoil spring discharges discussed later in the report. Wells 001- EPSTEXT.DOC 03/14/96 Page 3