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1 <br />' Specific Conduclivity/I'otal 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 at 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-I.5 since 1995. The source of the elevated values is not readily identifiable. A few factors <br />which may have contributed to the elevated values were mentioned in the 1996 Report (i.e., inundation of the area in late <br />spring of 1995 and the laying of telephone cable immediately upstream of the area during the summer of 1995). If the <br />elevated values resulted from [hose activities, the values should have returned to more historic levels during the 1996. 1997 <br />' and 1998 monitoring periods. However, the values have remained elevated. It appears that the alluvium in this area is <br />reflecting upstream alluvial water containing high levels of TDS, possibly from an old abandoned underground mine up the <br />' Little Trout Creek drainage. This conclusion is based partially on the similarity of the water quality between TR-I.5 and WR- <br />I. As previously discussed in the surface water section, data taken between October 1990 and August 1992 is believed to be <br />' invalid due to instrument errors. <br />Conductivity and TDS in Well WR-I have progressed from an elevated state each spring to a lower state in the 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 to that of the stagnant saturated zone. The 1997-1999 data suggests that 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 the <br />summer progresses. <br />' Calcium/Magnesium/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. TR-I.5 generally contained the lowest concentrations of cations with a <br />slight increase occurting downstream at TR-3 and TR-4 for the majority of the record. However, elevated levels of these <br />t parameters at TR-I.5 began to occur in 1995 consistent with the elevated Conductivity and TDS levels previously mentioned. <br />The sodium level for WR-I of 454 mg/I obtained during October 1991 is believed to be an analytical error. Levels <br />' measured prior to and after that sample date do not support the high concentration and followed the expected trend. <br />' 31 <br />