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There +vas a small increase in the average salt content of the Foidel Creek alluvial groundwater <br />• starting in the 1987 water year and continuing through the 1992 water year. This is probably <br />due to the relatively low runoff which has persisted since 1987. The water quality in the Foidel <br />Creek alluvial wells show a slight downstream increase in total dissolved solids and conductivity <br />and change from asodium-bicarbonate type to a mixed calcium-sodium-bicazbonate-sulfate type. <br />The change is apparent in the reach behveen the 009-S-10 well and the OOl-S-S well. This is <br />primarily attributable to recharge of alluvium by Foidel Creek water which receives sediment <br />pond discharges, containing elevated concentrations of dissolved solids, calcium and sulfate, in <br />the reach of Foidel Creek above the 001-5-5 well. The sediment pond water is largely derived <br />from spoil runoff and spoil springs. The spoil springs, in particular, are characterized by high <br />sulfate, calcium and dissolved solids concentrations. There is no indication of any significant <br />increase in trace metals in the alluvial groundwater during 1992. <br />The water quality data for the Fish Creek alluvial wells upstream and downstream of Mine 2 do <br />not indicate any impacts (Figure IS). The 006-AW-2 well, downgradient from the discharge <br />point, does show a slightly higher conductivity during the baseFlow period than in previous <br />years. The data does ttot indicate any significant changes in the trace metals concentrations. <br />The iron and manganese levels in the wells, including the upstream well, are often relatively <br />High. <br />Spoils <br />Five wells in the spoils are monitored. They are all located at Mine 1 and were installed in <br />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 are presented on Figures 16 through 19. <br />The water levels non»al{y have a similar pattern to the alluvial wells: they respond rapidly to <br />the spring runoff and then decline rapidly in the summer. Wells 026-SP-1 and 026-SP-3 are <br />sometimes dry by the fall, although this has not happened since 1988. These water levels <br />closely mirror fife pattern of the spoil spring discharges discussed later in the report. <br />• <br />-5- <br />