Fort
Patrick Henry Reservoir
Ecological
health rating
Fort Patrick Henry Reservoir rated poor in 2011. Fort Patrick Henry has received a fair or poor rating every year except 2003, when it rated good due primarily to improved chlorophyll levels (see discussion below).
TVA monitors one location on Fort Patrick Henry Reservoir—the deep, still water near the dam, called the forebay—usually on a two-year cycle.
Fort Patrick
Henry Reservoir Ecological Health Ratings, 1994-2011
Click chart for raw
data.
The table below
shows the ratings for individual ecological health indicators at Fort
Patrick Henry in 2011. These ratings are briefly explained in the paragraphs
that follow.
|
Ecological
Health Indicators at
Fort Patrick Henry Reservoir, 2011
|
|
Monitoring
location
|
Dissolved
oxygen
|
Chlorophyll
|
Fish
|
Bottom
life
|
Sediment
|
| Forebay |
|
|
|
|
|
Dissolved oxygen
Dissolved oxygen rated good, as in previous years. The reservoir’s small size and short residence time (the length of time the water sits in the reservoir) inhibits it from becoming thermally stratified and from developing low dissolved oxygen levels (less than two milligrams per liter) during the summer.
Chlorophyll
As in previous years, chlorophyll concentrations were elevated throughout most of the summer and autumn and rated poor. The exception was in 2003 when a shorter average residence time limited algae growth, resulting in the only good rating for this indicator.
Fish
The fish community rated fair. This indicator typically rates poor or fair. Monitoring consistently reveals a lower-than-expected number of species and a high proportion of tolerant individuals, such as gizzard shad.
Bottom life
Bottom life rated fair because a low variety of animals were found in samples collected from the reservoir bottom and most were species able to tolerate poor conditions. Bottom life typically rates within the fair range or at the upper end of the poor range.
Sediment
Sediment quality rated fair because samples contained PCBs and the concentration of arsenic was slightly above suggested background levels. Sediment quality typically rates fair due to low levels of chlordane, a pesticide previously used to control termites and crop pests, and/or copper exceeding suggested background levels. PCBs were last detected in 1994.
See definitions of
ecological health indicators and monitoring locations.
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Fish
consumption advisories
Fort Patrick Henry 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 Fort Patrick Henry Reservoir, visit the Water Quality Division of Tennessee Department of Environment & Conservation’s web page. http://www.tn.gov/environment/water.shtml
Tennessee Valley Authority
