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Ground Nater Level Summary. All alluvial wells are showing distinct seasonal water level • <br />fluctuations in response to periods of precipitation recharge or the lack of <br />precipitation. Overburden and coal well water levels are fluctuating in response to the <br />precipitation recharge, induced ground water flow to the mine pits, and in some cases, <br />changes in reservoir water levels due to lower precipitation end mining-related usage. <br />Spoil well water levels still indicate that only the furthest downslope highwall portions <br />of the spoil exhibit significant amounts of saturation. Levels in spoil wells near the <br />Madge Impoundment are largely controlled by water level fluctuations in the impoundment. <br />Pater Quality. Ground water samples were collected from 18 wells on a biannual basis. In <br />addition, tuo wells (25-5 end 42P1-Lw1) that are required to be sampled did not have <br />enough water to sample. The parameter list used for all wells sampled in 1992 is given on <br />Table 4 (Appendix A). <br />Analyses have been performed by AC2 Laboratory in Steamboat Springs, Colorado since May <br />31, 1983. AC2 Laboratory performs all analyses by EPA or equivalent methods. Samples are <br />delivered the day of collection to the lab in an iced cooler. The following discussion of <br />the analytical data collected during the reporting period is arranged by strata being • <br />monitored and coincides with the format (by aquifer type) in which the analytical data are <br />presented in Appendix D. Sampling techniques for each well are given in the remarks page <br />in the same appendix. Abbreviations used in the remarks are: CV = casing volume, BHV = <br />bore hole volume, EC = electrical conductivity, and FP = field parameters (pH, <br />temperature, and electrical conductivity). <br />Tables 5 through 10 (Appendix A) tabulate the percentage of milliequivalents per liter of <br />major ions and total dissolved solids (TDS) for each well sampled in 1992. Historical <br />date is provided for comparison purposes. The following discussion of water quality will <br />limit itself to a description of major ions and total dissolved solids (TDS) <br />concentrations. A separate section, Comparison of Ground Natcr Quality to Vater Use <br />Standards, wilt discuss any samples that exceed water use standards. <br />Alluvium. Well 32-A, located furthest upstream on Little Grassy Creek, displays a <br />NaNgCe•S04 type water. TDS values the past several years have fluctuated, implying that <br />TDS values have stabilized end that changes ere due [o annual changes in precipitation end <br />subsequent recharge. Progressing down valley, [he alluvium picks up spoils water • <br />discharge typified by calcium end magnesium replacing sodium es the major cation at Nell <br />6 <br />