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• Sodium concentrations in well008-79fi continue to exceed levels prevalent at all other monitoring locations <br />perhaps as a result of cation exchange as ground water migrates to the greater relative depths penetrated by <br />this well. The aforementioned cation exchange phenomena was thought to be evidenced by the increases <br />in sodium, bicarbonate, and SAR during the 1993 reporting period. During 1995, sodium concentrations <br />remained comparable to 1993 and 1994 levels, bicarbonate values remained static, and calculated SAR values <br />maintained the lower values established in the fall of 1994. <br />In general, the total dissolved solids concentration in both wells appears to have stabilized within established <br />ranges typical for each site. No anomalous values were encountered during 1995. TDS concentrations in <br />both wells remain within the normal range for the Wadge Overburden. The 1995 data does not indicate any <br />significant changes in trace metals concentrations. <br />Alluvium <br />The alluvial aquifer within the mine area is monitored with two alluvial wells (008-AV-1 and 008-AV-2) <br />completed in the Foidel Creek alluvium approximately 1000 feet upgradient from the confluence of Foidel <br />and Middle Creeks (see Figure 2). Both wells are completed to the base of the alluvium, about 14 feet <br />below the land surface. <br />• Water Levels - A plot of historic water levels in the two Foidel Creek Alluvial wells and in Foidel Creek <br />as measured at site 304 is presented as Figure 8. The water levels in the wells and stream show the expected <br />typical seasonal interrelationship of relatively rapid increases and declines associated with spring runoff. <br />This seasonal variation at these sites is more pronounced here than in other wells as expected because of the <br />shallow depths involved and proximity to Foidel Creek. The longer term trends in water levels at these sites <br />generally parallel the fluctuations observed in annual streamflows. <br />Water quality -Water quality data for the Foidel Creek Alluvium wells is presented on Tables 4, 4a, 5, and <br />Sa. Water quality data for Foidel Creek Site 304 monitored in association with the alluvial wells is <br />presented on Tables 11 and 1 la. Plots of historic field conductivities for both wells and dissolved solids for <br />well 008-AV-2 are presented as Figures 9, 10, and I1. Water quality constituent concentrations for most <br />parameters monitored during 1995 were within the established ranges historically associated with each site. <br />In May, however, well 008-AV-2 exhibited notably elevated dissolved solids and nutrient concentrations (see <br />Table 5). Subsequent values returned to normal ranges with the exception of a second elevated TDS <br />measurement occurring in August. Seasonal variations in field conductivity are evident in the alluvial wells. <br />This is likely associated with the flushing effect of the relatively low dissolved solids surface water <br />recharging the alluvial aquifer during spring runoff. The total dissolved solids concentration in the Foidel <br />Creek alluvial aquifer as measured at well 008-AV-2 appears to be steadily increasing since approximately <br />1988 (see Figure I1). CYCC will continue to monitor the direction of this trend. <br />L J <br />The 1995 data does not indicate any significant changes in trace metals concentrations although iron and <br />-3- <br />