Changes in water quality resulting from impoundment

Changes in stream water quality, resulting from recent impoundment, are presented and discussed. Extensive data reflecting pre- and post-impoundment conditions were statistically analyzed. The extent to which pollutants influence changes in water quality was minimal, as the drainage basin was relatively undisturbed by the activities of man. Chemical, physical, and microbiological parameters at stream stations were evaluated for three discrete periods of time: prior to closure of the dam, during filling of the active conservation pool, and following filling with the surface maintained near the top of the active conservation elevation. Effects of removing treated municipal waste effluents from a tributary were also evaluated. Water quality changes within the impoundment were compared with respect to season, year, station location, and depth of sampling. Critical factors in the impoundment, which contributed to water quality changes, are identified.