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Annual Hydrology Report April 28, 1988 Page 19 A comparison of 1987 monitoring data with previous years shows no significant trends or changes which can be associated with mining activity. Most springs are responsive to spring runoff, but flow rates are sporadic and many times do not correlate well with other seasonal parameters such as snowpack, precipitation, or streamflow. 2.3 Assessment of Surface Water and AVF's Efforts were made in previous annual reports to characterize baseline river water quality to evaluate potential changes in surface water quality due to mining activities at the Mt. Gunnison No. 1 Mine. Continuous monitoring of stream flows and periodic monitoring of spring dischazge rates are performed to provide the long term data base from which possible impacts of mining can be assessed. 2.3.1 Baseline Characterization of *Aater Quality and Streamflow A baseline characterization of North Fork water quality was performed in previous annual reports to evaluate the potential changes in North Fbrk water quality that could result from discharges at the Mt. Gunnison No. 1 Mine. Baseline characterization was performed downstream of the mine using data from the USGS stream gaging station on the North Fork near Somerset and from the West Elk Coal Co. water quality monitoring station on the North Fork below the mine for sample data prior to the stazt of construction in August 1981. Both stations were downstream of the surface facilities area and downstream of all discharge points. Baseline data and analysis of these data are provided in the Mining and Reclamation Plan for the Mt. Gunnison No. 1 Mine and in the First Annual Hydrology Report. 2.3.2 Comparison of Baseline Water Quality with Operational Data Of the ten parameters selected for baseline characterization, seasonal trends are apparent for TDS, TSS, and total iron. The other parameters do not exhibit seasonal variation. 7bta1 dissolved solids are least concentrated in the North Fork during the period between about May and July, probably because high-TDS ground water is diluted by snow runoff. 'Ibtal iron is most concentrated during this period of time. Zbtal suspended solids are most concentrated from April to July. A comparison of baseline water quality data in the North Fork of the Gunnison River to 1987 monitoring data shows no significant changes in water quality in the North Fork. Slightly higher results can be related to higher than previous fall precipitation and are not a result of mining. There does not appear to be any chancas in the North ior{ of the Gunni.~on River quality that can be attributed to affects of mining for water year 1987.