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runoff which recharges the aquifer. Often, bedrock (i.e., non alluvial) aquifers exhibit • a lag time between spring runoff and highest water Levels. (later levels then decrease (deepen) as late summer or fall approaches. Two cells (150V and 180V ), however, exhibited unusually high water levels in September, although most water levels dropped again in October. Two cells (16V and 3wC) exhibited unusually high water levels this year, white two other wells (3W and 13w) exhibited water levels that continued to drop. Annual water Level maximum and minimum values have, in general for wells drilled prior to 1987, been on the decrease (i.e., deepening) since 1986. This is probably due to the lower than normal snowpacks in the vicinity during the last five years. An exception to this would be the water levels at alluvial wells bA1 to bA3 which have shown higher water levels due to recently introduced irrigation in that area. Water Oualitv. Table 3 (Appendix A), Summary of Ground (later Monitoring 4ells, describes Che wells that are sampled and at what frequency they are sampled. In 1991, samples were collected from twelve wells. In addition, two wells from which water samples are required 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 AC2 Laboratory in Steamboat Springs, Colorado since May 31, 1983. AC2 Laboratory is EPA certified and performs all analyses by EPA or equivalent methods. Samples are delivered the day of collection to [he lab in an iced cooler. The following discussion of the analytical data collected during [he 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 mi lliequivalents per liter of major ions and total dissolved solids (7D5) 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 ui ll limit itself to a description of major ions. A separate section, Comparison of Ground Water Quality to Ua[er Use Standards, will list [hose samples that exceed water use standards. • 4