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Hiwassee Reservoir

Ecological health rating

The overall ecological health condition for Hiwassee Reservoir rated fair in 2012, similar to all previous years monitored except 2006, when Hiwassee received a good rating. That was largely because bottom life rated at the upper end of its historic range at both monitoring locations in 2006. Throughout the years, common issues have been elevated chlorophyll concentrations, low dissolved oxygen concentrations in the lower water column, and poor ratings for bottom life.

TVA monitors two locations on Hiwassee Reservoir — the deep, still water near the dam, called the forebay, and the middle part of the reservoir — usually on a two-year cycle.


Hiwassee Reservoir Ecological Health Ratings, 1994-2012

reservoir ratings chart

Click chart for raw data.  

The table below shows the ratings for individual ecological health indicators at Hiwassee in 2012. These ratings are briefly explained in the paragraphs that follow.

Ecological Health Indicators for
Hiwassee Reservoir, 2012

Monitoring locations

Dissolved oxygen



Bottom life



Dissolved oxygen

Dissolved oxygen rated poor at both monitoring locations because concentrations were low (less than two milligrams per liter) in a portion of the lower water column during the summer. Dissolved oxygen has rated poor most years at the forebay, but ratings at the mid-reservoir have varied between good, fair and poor.


Chlorophyll rated good at both monitoring locations. Annual average chlorophyll concentrations have fluctuated through time at both locations, resulting in good, fair, and poor ratings.


The fish community rated good at both monitoring locations. The fish community rated good all years except 2008, when it rated at the upper end of the fair range at the forebay because species diversity and catch rates were slightly lower than expected.

Bottom life

Bottom life rated poor at the forebay and fair at the mid-reservoir. This is comparable to the poor to “low fair” ratings in most previous years. The benthic communities at both monitoring locations are characterized by low density and diversity of organisms.


Sediment quality rated good at the mid-reservoir and fair at the forebay because low levels of PCBs were detected. Chlordane were detected in samples from both locations in 1993 and 1998; no other contaminants have recorded concentrations above background levels.


See definitions of ecological health indicators and monitoring locations.


Fish consumption advisories

Hiwassee 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 Hiwassee Reservoir, visit the Epidemiology Division of North Carolina Department of Health and Human Services’ web page.


lake photo

Hiwassee Reservoir is located on the Hiwassee River in western North Carolina.


More about Hiwassee

Sport fishing ratings

General information

To see monitoring results for other TVA reservoirs, choose from the list below.

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