Reservoir releases improvements
Since TVA implemented its reservoir-releases-improvement program, dissolved-oxygen concentrations have increased dramatically in more than 300 miles of river downstream from TVA dams, and wetted habitat is maintained in 180 miles of river previously impacted by intermittent drying. Studies show an increase in the number and diversity of fish and insects in these areas, as well as a significant growth in tailwater fishing, which aids local economies.
With regard to fish communities, recovery is most pronounced in warm tailwaters. A good example is the Douglas Dam tailwater where the number of native species found at the Saffil Island monitoring station has increased from 14 species (counted in the 1987 survey, the first year of sampling) to more than 35 species in recent years. Recovering fish communities appear healthier as well, because fewer tolerant fish species, such as common carp and gizzard shad, are found. Conditions also have improved in cold tailwaters, which now support healthier trout populations that are characterized by better survival and better growth.
TVA’s tailwater improvements have received national recognition from the Wildlife Habitat Council and the National Hydropower Association and have been applauded by state resource agencies, Trout Unlimited, and other organizations. The program also has been credited with making the reintroduction of lake sturgeon to the upper Tennessee River system possible.