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presented as Figure 20. The data indicates no impact on alluvial water levels related to <br />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. The <br />laboratory measurements did not show the same high levels during that period. Only <br />Well AVF-3 has shown an upward trend in dissolved solids to above 2000 mg/L. The <br />concentration had decreased to below 2000 mg/L in 1993 and 1994 but returned to <br />above 2000 mg/L in 1995 and stayed fairly consistent through 1998; however, it is still <br />within the range established during the period of 1988 to 1995 and does not appear to <br />represent a significant change. There is also a correlative increase in calcium, <br />magnesium, sulfate and chlorides. The source of this change is not known. However, it <br />is unlikely due to mine discharge because of the discharge's downgradient location and <br />the dissimilar chemical composition of mine discharge water. The mine discharge water <br />is strongly sodium-bicarbonate water with a conductivity of approximately 1500 mg/I, <br />while AVF-3 water is typically a mixed sodium-magnesium-calcium-bicarbonate-sulfate- <br />chloride water with conductivity averaging approximately 2000 mg/I. The noted <br />increase in conductivity in well AVF-3 does not appear to be related to the wastewater <br />lagoon as the conductivities in the well water have historically exceeded the levels <br />01-044 1998 AHR Page 8 <br />