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V. SUMMARY Since 1979, streamflow water quality monitoring has been conducted up- and downstream of the mine. The water type above the mine at monitoring site SW-N1 is a calcium-magnesium-bicarbonate type, indicating that water quality at this location is strongly influenced by irrigation water. The water type below the mine at monitoring site SW-N3 is a calcium-magnesium-sulfate type, reflecting the geochemical influence of the spoil material. For the purpose of assessing impacts of the mining operation on Tuttle Draw, water quality trends over time and water uses were analyzed. Water quality trends were analyzed separately during high flow and low flow periods to determiine if the large irrigation contributions to flow, during the period June through September, masked a gradual degrading trend in Tuttle Draw. The low flow period analyzed was from November to February. Table 8 presents the results of the above-defined seasonal analyses at sites SW-N1 (upstream) and SW-N3 (downstream) • for the period of record. During the period of record, there was no measurable increase in concentrations of chemical constituents at site SW-N3 for either flow season. Water quality analyses at SW-N1 indicate that the water is suitable for use as livestock drinking water. Higher concentrations of most chemical constituents have always been determined at site SW-N3 below the mining operation. The water quality at site SW-N3 is still quite suitable for use as livestock drinking water. Mean TDS values during the low flow period are approximately 2700 mg/1. The retommended level for livestock is 5000 mg/1. Also, waters sampled as part of complying with NPDES Permit No. CO-0000213 have only once exceeded limits set by the Colorado Department of Health, In summary, the impacts of runoff from reclaimed areas on the downstream water quality in Tuttle Draw are minimal. There is • no trending degredation of the water quality and the water use 105