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presented in Appendix C. The discussion of water quality will be <br /> limited to a description of total dissolved solids (TDS) concentrations. <br /> A separate section, Compar ison of Ground Water Quality to Water Use <br /> Standards, will discuss any samples that exceed water use standards. <br />Data for each well in this appendix begins with a listing of the water <br />quality data collected during the past two years, followed by water <br />level measurements and remarks explaining the sampling procedure. This <br />is followed by a plot of TDS versus time for the entire period of <br />record. The regression line on this plot is generated by a method known <br />as LOWESS (LOcally WEighted Scatterplot Smoothing). A smoothness factor <br />of 1.0 (on a scale of 0 to 1) was used, which results in maximum <br />"smoothing". Finally, this plot is followed by a table listing historic <br />TDS values and percent milliequivalents for major ions. <br />- Alluvium. Well 32 is located furthest upstream on Little Grassy <br />Creek. Review of the TDS plot indicates an increasing trend. This is <br />. due to the contribution of waters from Spoil Springs 3, 4, and 5. <br />Further downstream, Well 6 has historically displayed an increasing TDS <br />trend although recently TDS values have dropped. Furthest downstream on <br />Little Grassy Creek and below NPDES 002, is Well 31A. It also displays <br />an increasing TDS trend. However, all three of these well's TDS trends <br />appear to be stabilizing. <br />Three wells are sampled in the Grassy Creek alluvium. Well 71 monitors <br />the alluvium upstream of mining at Seneca II. It displays an increasing <br />TDS trend. Well 33 monitors the Grassy Creek alluvium at the Little <br />Grassy Creek confluence. It displays an increasing TDS trend. We11 70 <br />monitors the alluvium below Seneca II and also downstream of the <br />confluence with Scotchmans Gulch. It interestingly displays a <br />decreasing TDS trend. <br />In the Cow Camp Creek alluvium (below NPDES 004), water quality is <br />measured at two wells. Well 46 displays a varying TDS trend, rising and <br />falling for no apparent reason. Since October 2001, the trend has been <br />7 <br />