Effects of Aeration and Minimum Flow Enhancement on the Biota of Norris Tailwater

摘要

In the Clinch River in east Tennessee, releases from Norris Dam had dissolved oxygen (DO) concentrations as low as 1 mg/L. TVA Launched a Reservoir Releases Improvement Program in 1980 to increase DO during the warmer months of the year and to provide a minimum flow in the Norris Dam tailwaters. Turbine venting increased minimum DO in the releases by 0.7 mg/L in 1981 and 2-3 mg/L in 1982-1985. A flow reregulation weir was installed in 1984 two miles below Norris Dam and provides a minimum flow of 200 cfs downstream. This report details the effects of aeration, increased minimum flow, and other factors on the trout fishery and macroinvertebrates of Norris tailwater. As a result, fishing effort, catch rate and harvest of trout increased significantly during the past 5 years; more stable and aesthetically pleasing flow conditions were established, and the State of Tennessee maintained a strong trout stocking program to meet the increased popularity of the stream following TVA efforts to improve fishery conditions. While aeration has improved the condition (plumpness) of trout somewhat during late summer and fall, the fish continue to show some effects of stress when DO levels fall below about 6 mg/L. 23 refs., 12 figs., 27 tabs. (ERA citation 13:014426)