The ecological health of Nickajack Reservoir scored at the upper end of the fair range in 2012. Historically, ecological health scores have fluctuated within the good range. The lower rating in 2012 was the result of two ecological indicators - chlorophyll and sediment quality - scoring at the lower end of their historic ranges.
Nickajack has consistently scored 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.
Nickajack Reservoir Ecological Health Ratings, 1994-2012
The table below shows the ratings for individual ecological health indicators at Nickajack in 2012. These ratings are briefly explained in the paragraphs that follow.
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