Normandy Reservoir rated poor in 2010, consistent with poor ecological health ratings since 2000. Historically, the main issue has been low dissolved oxygen. In 1994, TVA installed aeration equipment in the reservoir to add oxygen to the deep water near the dam and to improve conditions in the Duck River downstream from the dam. A new, larger compressor and four new diffuser lines were added to the aeration system in 1997. Two of the new diffuser lines extended upstream of the sampling location and influenced the ecological health ratings. Three indicators (dissolved oxygen, chlorophyll, and bottom life) exhibited marked changes. In 2006, a new sampling site for dissolved oxygen, chlorophyll, and sediment quality was established just upstream of the diffuser lines. The sampling site for bottom life was moved upstream in 2008. However, because of the small area that comprises the forebay of Normandy Reservoir, the aeration system continues to have some influence on two (dissolved oxygen and chlorophyll) of these three indicators. Results are discussed below.
TVA monitors one location on Normandy Reservoir — the deep, still water near the dam — usually on a two-year cycle. (Monitoring was changed to an every-other-year rotation after 1996).
Normandy Reservoir Ecological Health Ratings, 1994-2010
The table below shows the ratings for individual ecological health indicators at Normandy in 2010. These ratings are briefly explained in the paragraphs that follow.
Normandy 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 Normandy Reservoir, visit the Water Quality Division of Tennessee Department of Environment & Conservation’s web page. http://www.tn.gov/environment/water.shtml