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The following discussion of the analytical data collected during the <br />reporting period is arranged by strata being monitored and coincides <br />with the format (by aquifer type) in which the analytical data are <br />presented in Appendix D. The following discussion of water quality is <br />limited to a description of total dissolved solids (TDS). A separate <br />section, Comparison of Ground Water Quality to Water Use Standards, <br />lists those samples that exceed water use standards. <br />Data for each well in Appendix D begin with a listing of the water <br />quality data collected during the past year. This is followed by a plot <br />of TDS versus time for the entire period of record. The regression line <br />on this plot is generated by a method known as LOWESS, which is an <br />acronym for Locally Weighted Scatter Plot Smoothing (Cleveland, 1979). <br />Unless otherwise noted, a smoothness factor (SF) of 1 (on a scale of 0 <br />to 1) was used, which gives maximum smoothing. A statistical report <br />representing baseline (i.e., pre -mining) data for each well (when <br />available) is presented in Appendix Dl of the 2010 AHR. In this <br />statistics report, "censored data" refers to analytical values that were <br />below the detection limit, and consequently censored from the <br />min/max/mean calculations. The period for baseline conditions is listed <br />under "conditions specified" at the bottom of each page. <br />Alluvium. <br />One well currently monitors the Hubberson Gulch alluvium. Well WHAL7-2 <br />exists on Hubberson Gulch downstream of mine discharges from NPDES 006, <br />016 and 017. Its TDS plot shows a slightly increasing trend, with values <br />generally decreasing since 2005. A discussion of water quality from Dry <br />Creek Alluvial Well DCAL-02 is found in the following Ground Water Point <br />of Compliance Section. <br />Wadge Overburden. <br />Three wells monitor the Wadge overburden. North area Well WOV14 exhibits <br />a slightly increasing TDS trend, with values generally decreasing over <br />the past few years. Middle area Well WOV17 overall exhibits a decreasing <br />TDS trend, but with an unusually high value in 2008, 2009 and 2011. <br />5 <br />