Biological Responses to Improved Reservoir Releases

摘要

Since 1987, the Reservoir Releases Improvements (RRI) program provided minimum flows and enhanced dissolved oxygen (DO) content of rivers below Tennessee Valley Authority (TVA) storage hydroelectric facilities. Tailwater benthic macroinvertebrate and fish communities responded to improved water quality over time and distance. Aquatic biota in Douglas Tailwater responded more favorably than that in the adjacent Cherokee Tailwater, presumably because aeration at Douglas Dam preceded Cherokee Dam. After two years of sustained 4 mg/L DO below Douglas Dan, benthic invertebrate and fish communities improved at all stations, reaching good and excellent designations, respectively, at certain stations. Lacking two years of improved DO below Cherokee Dam, aquatic communities showed slight and erratic improvement over time, indicating minimum flows alone are insufficient to restore tailwater biota to desired levels.