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Specific Conductivity/Total Dissolved Solids <br />Specific conductivity (Figure 23) and total dissolved solids (Figure 24) values for the three alluvial wells have <br />remained fairly constant over the majority of the period of record. While Conductivity and TDS values a[ sites TR-3 and TR- <br />4 are consistent with values obtained during the baseline studies, these parameters and several others have elevated rapidly <br />and remained elevated at TR-1.5 since 1995. The source of the elevated values is not readily identifiable. A few factors <br />which may have contributed to [he elevated values were mentioned in the 1996 Report (i.e., inundation of [he area in late <br />spring of 1995 and [he laying of telephone cable immediately upstream of the area during the summer of 1995). If the <br />elevated values resulted from those activities, [he values should have returned to more historic levels during [he 1996-2002 <br />monitoring periods. However, the values have remained elevated. It appears that the alluvium in this area is reflecting <br />upstream alluvial water containing high levels of TDS, possibly from an old abandoned underground mine up the Little Trout <br />Creek drainage. This conclusion is based partially on [he similarity of [he water quality between TR-1.5 and WR-l. <br />Conductivity and TDS in Well WR-l have progressed from an elevated state each spring [o a lower state in [be fall <br />for the past several years. This phenomenon was caused by infiltration of snowmelt water leaching various minerals within the <br />unsaturated zone of reclaimed spoil. As the enriched Flow was released over the course of the summer, the conductivity <br />values lessened [o that of the stagnant saturated zone. The 2000-2002 data suggests [hat the unsaturated zone may be almost <br />depleted of leachate. The mounded aquifer exhibits a more diluted state each spring with a return to steady-state as [he <br />summer progresses. <br />Cal ci um/M agnesi um/Sodium <br />Calcium (Figure 25) is the major cation found in all of the wells with concentrations of sodium (Figure 26) and <br />magnesium (Figure 27) occurring in lesser quantities. The sodium concentration at TR-1.5 in May 200] was 179 ppm. This <br />value is inconsistent with the historical sodium concentrations and the levels after May 2001. Therefore, either sample <br />contamination or laboratory error is suspected. TR-I.5 generally contained the lowest concentrations of cations with a slight <br />increase occurring downstream at TR-3 and TR-4 for the majority of the record. However, elevated levels of these <br />parameters at TR-1.5 began to occur in 1995 consistent with the elevated Conductivity and TDS levels previously mentioned. <br />31 <br />