Norris Reservoir
Contents of this page
Ecological health rating
Norris Reservoir rated fair in 2005 monitoring by TVA.
Swimming advisories
The state of Tennessee has not issued any advisories against swimming in Norris Reservoir.
Fish consumption advisories
The state of Tennessee has not issued any advisories against consuming fish from Norris Reservoir.
Related Links
More about Norris Reservoir
Sport fishing ratingsGet the facts on the availability of important sport species.
General information
Monitoring river conditionsFind out how TVA evaluates the river systems ecological health and suitability for human use.
Ecological health rating
TVA monitored Norris Reservoir annually from 1991 through 1995 to establish baseline data on the reservoirs ecological health under a range of weather and flow conditions. Norris is now monitored every other year.
As in previous years, the ecological health of Norris Reservoir was rated fair in 2005.
Norris Reservoir Ecological Health Ratings, 1994-2005
Click chart for raw data.
The table below shows the ratings for individual ecological health indicators at Norris in 2005. These ratings are briefly explained in the paragraphs that follow.
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Dissolved oxygen
The most significant ecological health issue on Norris is low dissolved oxygen levels. Dissolved oxygen rated poor at all three monitoring locations because the lower half of the water column contained little oxygen (less than two milligrams per liter) from late summer through early autumn.
This issue is mostly the result of the reservoir’s basic characteristics. Norris is a deep tributary storage reservoir with a long summer retention time; that is, it can take more than 200 days for water to move through the reservoir. As the summer sun beats down on the surface of the reservoir, a warmer layer of water forms on top of a cooler layer. The layers do not mix, so the bottom layer becomes devoid of oxygen as it is used up by decaying plants and other materials that settle to the bottom.
TVA has installed equipment to add oxygen to the water as it is flows through Norris Dam. Learn more about these improvements.
Chlorophyll
Chlorophyll rated good at all three monitoring locations. Chlorophyll typically rates good on Norris.
Fish
The fish community received good ratings at both mid-reservoir monitoring locations due to good species diversity and population characteristics. Fewer fish and fish species were collected at the forebay monitoring location, resulting in a fair rating.
Bottom life
Bottom life ratings varied by location: poor at the forebay, fair at the Clinch mid-reservoir, and good at the Powell mid-reservoir. Bottom life typically rates good or “high fair” at the mid-reservoir sites, but there is greater variability in scores for the forebay, which has rated fair or poor in recent years. The poor ratings for the forebay, as in 2005, have resulted from collecting fewer organisms and fewer species.
Sediment quality
Sediment quality rated fair at all three monitoring locations. As in past years, forebay sediments had elevated concentrations of arsenic and lead. Lows levels of chlordane, a pesticide previously used to control termites and crop pests, were present in the sediments at both mid-reservoir locations.
Swimming advisories
TVA has not issued any swimming advisories for Norris Reservoir.
E. coli bacteria levels in samples collected in 2007 were within the state of Tennessee’s guidelines for water contact.
The following locations were sampled in 2007:
Site Name |
Location |
County |
State |
|---|---|---|---|
Lakeview Boat Ramp |
Clinch River Mile 118.0, Hunting Creek |
Union |
TN |
Loyston Point Beach |
Clinch River Mile 96L, Mill Creek Mile 1.4 |
Union |
TN |
Big Ridge State Park Beach |
Clinch River Mile 98L, Big Ridge Lake |
Union |
TN |
Anderson County Park Swim Site |
Clinch River Mile 87.6L |
Union |
TN |
Miller Island Clinch River Canoe Access |
Clinch River Mile 77.2 |
Campbell |
TN |
Cedar Grove Marina Boat Ramp |
Clinch River Mile 124.0R |
Union |
TN |
Union County Marina Boat Ramp |
Powell River Mile 30.0R |
Union |
TN |
Fish consumption advisories
There are no fish consumption advisories for Norris Reservoir. TVA collected channel catfish and largemouth bass from the reservoir for tissue analysis in fall 2005. The results, which were similar to those of previous years, will be provided to state agencies in Tennessee. These species will be collected for analysis again in fall 2009.

