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A hydrologic monitoring program was implemented at the Chimney Rock Mine located 20 miles southwest of Pagosa Springs, Colorado in October 1980. This program currently consists of three surface stations and eight ground water wells. The results of monitoring activities for the period of January through September 1988 are summarized in the following paragraphs with summary data sheets attached. Surface Water MonitorinL~ Surface water monitoring was conducted a[ three locations on Stollsteimer Creek (S-1, S-2 and S-3}. Flows conditions over the quarter ranged from summer low Oow to high [low caused by intense thundershowers. On August 18 and 28, precipitation at the site was measured at 2.5 and 1.25 inches, respectively. The event on August 18 exceeded the calculated 10 year-24 hour storm event. Flow measurements collected a[ the three surface stations during the quarterl}' sampling on September 21, 1985 ranged from 1.8 to 2.2 cfs which is a low Oow condition for Stollsteimer Creek. Water quality samples were collected at each of the three surface stations during the September sampling. The water is classified as a calcium/sulfate-bicarbonate water with relatively low concentrations of metals and mineralization. The lower flow conditions have shifted the major ion balance back to a sulfate/biprbonate water over the more sulfate type water observed in lv4arch 1988. Results were similar over the three stations. The mine has continued to be inactive with the only surface disturbance being the reconstruction of the Stollsteimer channel below the haul road crossing. Even with some minor disturbance in the creek, TSS concentrations are higher above the activity (68 mgll) than below (35 and 28 mg(l). A quarterly pond inspection was conducted in September. No erosional or structural problcnts were observed. Recent heavy rains have resulted in an increase in sediment deposited in the ponds. Ground Water Monitorin Alluvial ground water was monitored at wells A-1, W-1, W-5 and W-7. The deeper Fruitland Formation was monitored at wells W-6, W-9 and W-10. The reclaimed area was monitored at well W-]6. Water levels monitored in [he four alluvial wells exhibited a general decrease over the levels measured in June. This corresponds with the decrease in surface Oow of Stollsteimer Creek- Results of water samples collected in September at wells A-1, W-5, and W-7 indicate similar characteristics as surface water. Well A-1 had a much higher degree of ionization over the other two wells. Well A-1 also had much higher metal concentrations of iron, manganese, and aluminum with elevated wnductit~ty and TDS. Well A-1 exhibited asodium/sulfate type water rather than acalcium/bicarbonate type. This change in water quality may be from the mining activity and seepage from the reclaimed pit located up-gradient of the well. The deeper Fruitland Formation was monitored at stations W-6, W-9 and W-10. Water levels bf the three wells decreased over the quaver. Water quality samples were collected at stations W-9 and W-10 in September. The water was consistent with previous samplings being asodium-calcium bicarbonate type with somewhat high concentrations of metals. Well W-16 in the reclaimed area exhibited a slight decrease in water level over the monitoring period. Water quality can be classified as sodium/bicarbonate-sulfate with a higher degree of ionization over the other deep wells sampled. Concentrations of iron, nitrate and ammonia were also elevated. Trace metal concentrations were low.