Chatuge Reservoir

Ecological health rating

The ecological health condition of Chatuge Reservoir rated in the middle of the fair range in 2010. Chatuge has rated either poor or at the low end of the fair range in most previous years. The mid-fair rating in 2010 was largely because of an improvement in bottom life, first observed in 2008, and improved dissolved oxygen conditions.

Chatuge also rated in the middle of the fair range in 2001 due to improved chlorophyll and dissolved oxygen conditions. Higher ecological health ratings in 1994 and 1996 were due to the fact that several indicators — chlorophyll, dissolved oxygen, and sediment quality — concurrently rated near the upper end of their historic ranges.

Weather conditions, particularly the timing and amount of rainfall, and the related changes in runoff have proved to be major factors in the variation of ecological health scores for Chatuge and many other reservoirs. In the forebay area of tributary reservoirs with long residence times (that is, where water sits for a relatively long period), dissolved oxygen and chlorophyll, the indicators most responsive to changes in weather conditions, tend to rate better during times of drought and worse during periods of higher than normal rainfall and runoff. This is because fewer nutrients and less organic material are washed into the reservoir when rainfall and runoff are low, and that tends to produce lower chlorophyll concentrations and less oxygen demand to decompose organic materials.

TVA has monitored two locations on Chatuge Reservoir — the deep, still water near the dam and the Shooting Creek location — annually since 1998.

Chatuge Reservoir Ecological Health Ratings, 1994-2010

Click chart for raw data.

The table below shows the ratings for individual ecological health indicators at Chatuge in 2010. These ratings are briefly explained in the paragraphs that follow.

Monitoring locations	Dissolved oxygen	Chlorophyll	Fish	Bottom life	Sediment
Ecological Health Indicators at Chatuge Reservoir, 2010
Forebay	Fair	Fair	Fair	Good	Fair
Shooting Creek	Fair	Fair	Fair	Fair	Poor
Dissolved oxygen Dissolved oxygen rated fair at both monitoring locations due to low concentrations (< 2 mg/l) in a small proportion of the lower water column from late September through October. Ratings have fluctuated between fair and poor in response to the timing and amount of rainfall. Chlorophyll Chlorophyll concentrations were slightly elevated resulting in a fair rating at both monitoring locations. Similar to dissolved oxygen, chlorophyll ratings have fluctuated between good, fair, and poor. Fish The fish community rated fair at both monitoring locations, the same as in most previous years. Catch rates were lower than expected, and species diversity was fair. Bottom life Bottom life rated at the low end of the good range at the forebay and fair at the Shooting Creek location. The forebay also received a good rating in 2008. Historically, bottom life has rated fair or poor at both locations because relatively few organisms are found in samples collected from the reservoir bottom, and most are species able to tolerate poor conditions. The higher rating at the forebay in 2008 and 2010 is attributable to collection of a greater variety of organisms, suggesting a subtle improvement in bottom life at this location. However, tolerant species still comprise the largest percentage of the community at both locations. Sediment Sediment quality rated fair at the forebay because of slightly elevated concentrations of copper. The Shooting Creek location rated poor due to elevated concentrations of chromium, copper, and nickel. Elevated concentrations of one or more of these metals are usually detected in the sediments of Chatuge. See definitions of ecological health indicators and monitoring locations.

Fish consumption advisories

Chatuge 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 Chatuge Reservoir, visit the Environmental Protection Division of Georgia Department of Natural Resources’ web page. http://www.gaepd.org/Documents/fish_guide.html