Pickwick Reservoir

Ecological health rating

The overall ecological health condition in Pickwick Reservoir rated fair in 2010, with the lowest score (63) to date due primarily to the reservoir’s first poor rating for the dissolved oxygen indicator at the forebay and to chlorophyll and bottom life rating near the low end of their historic ranges at several monitoring locations. Pickwick’s score (66) in 2008 was the second lowest score to date largely due to lower scores for these same indicators. Conversely, the higher score (84) in 2004 resulted from these indicators concurrently rating at the upper end their historic ranges. Pickwick, however, typically scores near (slightly above or slightly below) the break point between a good and fair rating. Year-to-year variation primarily depends on chlorophyll concentrations (which are affected by reservoir flows), and conditions in the Bear Creek embayment, which generally rates lower than at other monitoring locations on the reservoir.

Pickwick Reservoir Ecological Health Ratings, 1994-2010

Click chart for raw data.

The table below shows the ratings for individual ecological health indicators at Pickwick in 2010. These ratings are briefly explained in the paragraphs that follow.

Monitoring locations	Dissolved oxygen	Chlorophyll	Fish	Bottom life	Sediment
Ecological Health Indicators for Pickwick Reservoir, 2010
Forebay	Poor	Poor	Fair	Fair	Good
Mid-reservoir	Good	Poor	Fair	Fair	Good
Bear Creek embayment	Good	Poor	Fair	Fair	Good
Inflow (near Wilson Dam)			Good	Good
Dissolved oxygen Dissolved oxygen rated poor at the forebay and good at the mid-reservoir and embayment monitoring locations. The forebay received a poor rating due to low dissolved oxygen concentrations (< 2mg/L) in the lower water column June through August. This is the first poor rating for dissolved oxygen at the forebay. This indicator usually rates good at the mid-reservoir, but ratings have varied between good and fair at both the forebay and embayment locations, generally in response to reservoir flow conditions. Chlorophyll Chlorophyll rated poor at the three locations monitored. Chlorophyll typically rates poor at the forebay and embayment locations and has fluctuated between good, fair, and poor at the mid-reservoir location. As with dissolved oxygen, reservoir flows have played a part in the year-to-year fluctuations as low-flow conditions tend to allow more time for algal populations to become established. Fish The fish community rated fair at the forebay, mid-reservoir and Bear Creek embayment and good at the inflow monitoring location. The mid-reservoir’s score has been slightly lower since 2008, with a mid-fair rating, as compared to high-fair to good ratings in previous years, primarily due to collection of a slightly higher percentage of tolerant individuals. Results for the other locations were consistent with previous monitoring years. Fish community ratings generally have fluctuated between good and "high fair" ratings at all locations. Bottom life Bottom life rated good at the inflow location and fair at the forebay, mid-reservoir, and embayment locations. The forebay and mid-reservoir received scores that were at the lower end of their historical ranges because of a higher proportion of tolerant organisms and reduced overall diversity. The lower ratings likely were the result of the low dissolved oxygen conditions that developed along the reservoir bottom in 2010. Sediment Sediment samples collected from the reservoir bottom were free of pesticides and PCBs, and concentrations of metals were within expected background levels, resulting in good ratings for sediment quality at all monitoring locations. See definitions of ecological health indicators and monitoring locations.

Fish consumption advisories

Pickwick 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 Pickwick Reservoir, visit the Water Quality
Division of Tennessee Department of Environment & Conservation’s
web page. http://www.tn.gov/environment/water.shtml ; the
Epidemiology Division of Alabama Department of Public Health’s web page. http://www.adph.org/tox/index.asp?ID=1360 and the Mississippi
Department of Environmental Quality’s web page. http://www.deq.state.ms.us/MDEQ.nsf/page/FS_Mississippi_Fish_
Advisories?OpenDocument