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previously. Neither well exhibited water levels outside the ranges previously observed, nor do they exhibit any long-term discernable trend. Ground Water Level Summary. During 1993, most aquifers et Seneca 11-W exhibited a typical seasonal fluctuation. Peter levels were highest (shallowest) after the spring snowpack runoff which recharges the aquifer. Often, bedrock (i.e., non-alluvial) aquifers exhibit a leg time between spring runoff end highest water levels. Pater levels then decrease (deepen) as late summer or fall approaches. Many wells exhibited higher water levels this year then they have for the past several years. This is primarily due to the greater amount of snowpack runoff this spring. Water quality. fable 3 (Appendix A), Summary of Ground Water Monitoring Wells, describes the wells that were sampled, the sample frequency during the 1993 water year, and site characteristics. In 1993, samples were collected from 21 wells. In addition, two wells from which water samples are required (Wells 20A and 160V) were either dry or had not enough water to sample. Table 4 (Appendix A) shows the ground water parameter list used for all wells. Analyses have been performed by ACZ Laboratory in Steamboat Springs, Colorado since May 31, 1983. ACZ Laboratory performs all analyses by EPA or equivalent methods. Samples are delivered the day of collection to the lab in en iced cooler. The following discussion of the analytical data collected during the reporting period is arranged by strata being monitored and coincides with the format (by aquifer type) in which the analytical data are presented in Appendix D. Sampling techniques for each well are given in the remarks page in the same appendix. Tables 5 to 7 (Appendix A) tabulate the percentage of milliequivalents per liter of major ions and total dissolved solids (TDS) for each well sampled. All data prior to 1990 has been averaged together to provide the baseline (i.e., premining) conditions that existed. In addition, the range of total dissolved solids (TDS) that existed prior to mining is also given. Since mining began in 1990, data from that point on is listed separately. The following discussion of water quality will limit itself to a description of major ions. A separate section, Comparison of Ground Water Quality to Voter Use Standards, will list those samples that exceed water use standards. _. Alluvium. Samples from Well bA2 display a CaMgNa-HC03 type water with an average TDS vat~ues of 703 mg/l in 1993. This is higher than the 611 mg/l baseline average, but falls 4