Tennessee Valley Authority
Nickajack Reservoir
Ecological health rating
As in previous years, Nickajack Reservoir rated good in 2009. The ecological health score for Nickajack has consistently been among the highest of all the reservoirs monitored by TVA. Nickajack is a small, narrow reservoir with a short retention time. It usually takes only three or four days for water to flow through the reservoir, which helps keep the water mixed, preventing it from stratifying (separating into layers of different temperatures) during the summer. This allows oxygen in the lower water column to be replenished and limits algal growth, thereby reducing chlorophyll concentrations.
TVA monitors two locations on Nickajack Reservoir—the deep, still water near the dam, called the forebay, and the riverlike area at the extreme upper end of the reservoir, called the inflow—usually on a two-year cycle.
Nickajack Reservoir Ecological Health Ratings, 1994-2009
Click chart for raw data.
The table below shows the ratings for individual ecological health indicators at Nickajack in 2009. These ratings are briefly explained in the paragraphs that follow.
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Fish consumption advisories
Nickajack Reservoir - TVA maintains a program to examine contaminants in fish fillets from TVA reservoirs and their major tributary streams on a rotational basis. The data collected from this program is distributed to the state officials who are responsible for placing or removing fish tissue consumption advisories on those bodies of water. For information on advisories currently in effect for Nickajack Reservoir, visit the Water Quality Division of Tennessee Department of Environment & Conservation’s web page. http://www.tn.gov/environment/water.shtml
