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WATER LEVELS <br />Groundwater levels in the alluvium have remained fairly regular, with normal seasonal <br />fluctuations, apparently related to changes in river levels. Groundwater levels in the <br />alluvium are plotted in Figure 19. A piezometric map for the Williams Fork Alluvium is <br />presented as Figure 20. The data indicates no impact on alluvial water levels related <br />to mining. <br />WATER QUALITY <br />Summaries of the water quality data for the alluvial wells are presented in Tables 21 <br />through 26. A plot of field electric conductivity versus time is presented in Figure 21. <br />There is no conclusive evidence of seasonal variation of water quality in the alluvium. <br />• The field conductivity of Well AVF-5 was above normal in late 1983 and early 1984. <br />The laboratory measurements did not show the same high levels during that period. <br />Only Well AVF-3 has shown an upward trend in dissolved solids to above 2000 mg/L. <br />The concentration had decreased to below 2000 mg1L in 1993 and 1994 but returned <br />to above 2000 mg/L in 1995 and stayed fairly consistent during 1996; however, it is <br />still within the range established during the period of 1988 to 1995 and does not <br />appear to represent a significant change. There is also a correlative increase in <br />calcium, magnesium, sulfate and chlorides. The source of this change is not known. <br />However, it is unlikely due to mine discharge because of the discharge's downgradient <br />location and the dissimilar chemical composition of mine discharge water. The mine <br />discharge water is strongly sodium-bicarbonate water with a conductivity of <br />• C-81.044 1996 AHR. I'1EMPIREWHR\96AHR\EMPAHR96.DOC Page 9 <br />