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• year. This is probably due to the relatively low runoff which has persisted since 1987. <br />The water quality in the Foidel Creek alluvial wells show a slight downstream increase <br />in total dissolved solids and conductivity and change from asodium-bicarbonate type to <br />a mixed calcium-sodium-bicarbonate-sulfate type. The change is apparent in the reach <br />between the 009-S-10 well and the 001-S-5 well. This is primarily attributable to <br />rechazge of alluvium by Foidel Creek water which receives sediment pond discharges, <br />containing elevated concentrations of dissolved solids, calcium and sulfate, in the reach <br />of Foidel Creek above the OOl-S-S well. The sediment pond water is largely derived <br />from spoil runoff and spoil springs. The spoil springs, in pazticulaz, aze characterized <br />by high sulfate, calcium and dissolved solids concentrations. There is no indication of <br />any significant increase in trace metals in the alluvial groundwater during 1991. <br />The water quality data for the Fish Creek alluvial wells upstream and downstream of <br />Mine 2 do not indicate any impacts (Figure 15). The 006-AW-2 well, downgradient <br />from the discharge point, does show a slightly higher conductivity during the basetlow <br />period than in previous years. The data does not indicate any significant changes in the <br />trace metals concentrations. The iron and manganese levels in the wells, including the <br />• upstream well, are often relatively high. <br />Spoils <br />Five wells in the spoils aze monitored. They are all located at Mine 1 and were <br />installed in 1985 and 1986. Two of these are only monitored for water level. <br />Water Levels <br />The plots of the historic water levels in the spoil wells aze presented on Figures I6 <br />through 19. The water levels normally have a similaz pattern to the alluvial wells: <br />they respond rapidly to the spring runoff and then decline rapidly in the summer. <br />Wells 026-SP-1 and 026-SP-3 are sometimes dry by the fall, although this has not <br />happened since 1988. These water levels closely minor the pattern of the spoil spring <br />discharges discussed later in the report. <br /> <br />- 5 - <br />