Fort Patrick Henry Reservoir

Fort Patrick Henry Reservoir rated “fair” in 2016. 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).

The ecological health of Fort Patrick Henry Reservoir has been monitored using the same methodology since 1994. Ecological health evaluations focus on five indicators: dissolved oxygen, chlorophyll, sediment quality, benthic macroinvertebrate community (bottom life), and the fish assemblage. TVA monitors one location on Fort Patrick Henry Reservoir — the deep, still water near the dam, called the forebay (South Fork Holston River Mile (SFHRM 8.7).

Ecological Health Ratings for Fort Patrick Henry Reservoir, 1994-2016


To view or export the data, click on the menu in the top-right corner of the chart.

Ecological Health Score Ranges:

 >72 = Good


 59-72 = Fair


 <59 = Poor

Ecological Health Indicators for Fort Patrick Henry Reservoir, 2016

Monitoring locationDissolved


Dissolved oxygen

Dissolved oxygen rated “good”, consistent with ratings of previous years. The reservoir’s small size and short residence time (the length of time the water sits in the reservoir) inhibit it from becoming thermally stratified and from developing low dissolved oxygen levels (less than two milligrams per liter) during the summer.


Similar to most previous years, chlorophyll in 2016 rated “poor”, as concentrations were elevated throughout most of the summer and autumn. The main exception to this trend was in 2003, when shorter residence times limited algae growth, resulting in the only “good” rating for this indicator.


The fish community rated “fair” in 2016. Historically, this indicator has rated “fair” or at the upper end of the “poor” range, as monitoring consistently reveals a moderate number of species and a high proportion of a few prolific species, such as gizzard shad and spotfin shiner. A total of twenty different species of fish was collected in 2016, and fish health was assessed a “good” rating with low incidences of disease and parasites.

Bottom life

Bottom life in 2016 rated “fair”. Bottom life has scored within the “fair” range or at the upper end of the “poor” range in past years because samples revealed a low diversity of organisms and most have been species able to tolerate a wide range of environmental conditions. 


Sediment quality in 2016 rated “good” because no PCBs or pesticides were detected in the sample and concentrations of metals were within suggested background concentrations. Sediment quality often rates “fair” due to one or more of the following contaminants: copper, PCBs, and/or chlordane.

Fish consumption advisories

TVA maintains a program to examine contaminants in fillets of fish collected from TVA reservoirs and their major tributary streams on a rotational basis. The data collected from this program are 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 Tennessee Wildlife Resource Agency.