Environmental Impacts of Drought in the Tennessee Valley

Ruane, Richard J.; Bruggink, David J.; Yeager, Bruce L.; ,

Environmental Impacts of Drought in the Tennessee Valley

by Richard J. Ruane, Tennessee Valley Authority, Chattanooga, United States,
David J. Bruggink, Tennessee Valley Authority, Chattanooga, United States,
Bruce L. Yeager, Tennessee Valley Authority, Chattanooga, United States,

Document Type: Proceeding Paper

Part of: Environmental Engineering

Abstract:

Beginning in June 1984, the Tennessee Valley region entered the most severe, extended period of drought since record keeping began in 1890. The historical annual average rainfall across the Tennessee Valley is 52 inches per year, and the deficit rainfall between 1980 and 1988 was 83 inches. The deficit between 1984 and 1988 was 64 inches. During the first ten months of 1988, precipitation was 63% of normal and runoff was only 41% of normal, indicating increased evapotranspiration and infiltration to depressed groundwater acquifers. For the four year period 1985 through 1988 streamflow available for refilling reservoirs during the mid-March to June springfill period averaged only 51% of normal, resulting in low summer levels particularly in the tributary impoundments. Water in storage in the tributary reservoirs east of Chattanooga - water available to supplement downstream flows in the Tennessee River mainstem reservoir projects - packed at only 62% of normal in 1988. This paper will describe the effects of the drought during the 1980's on (1) dissolved oxygen in the releases from TVA hydropower projects, (2) hydrogen sulfide occurrence in the releases from power projects, and (3) decreases in sauger reproduction due to reductions in power generation.

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