The overall ecological health condition of Pickwick Reservoir rated fair in 2012, with a score of 63. Pickwick has scored lower the past three years sampled compared to other years due primarily to three indicators (dissolved oxygen, chlorophyll and bottom life) concurrently rating near the low end of their historic ranges at several monitoring locations. Lower ratings (fair) for sediment quality also reduced the overall score in 2012. Conversely, the higher score (84) in 2004 resulted from all indicators rating near the upper end of their historic ranges. Pickwick, however, typically scores near (slightly above or slightly below) the breakpoint between a good and fair rating, with year-to-year variation primarily dependent 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.
Ecological Health Indicators at Pickwick Reservoir — 2012
|Bear Creek embayment||Fair||Poor||Good||Fair||Fair|
|Inflow (near Wilson Dam)||Fair||Good|
Dissolved oxygen rated fair at the forebay and embayment monitoring locations and good at the mid-reservoir. The fair ratings were the result of low dissolved oxygen concentrations (<2 mg/L) in the lower water column during some sample periods. This indicator usually rates good at the mid-reservoir, but ratings have varied between good and fair at the forebay and embayment locations, generally in response to reservoir flow conditions.
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. 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.
The fish community rated good at the forebay and Bear Creek embayment locations and fair at the mid-reservoir and inflow locations. Fish community ratings generally have fluctuated between good and "high fair" ratings at all locations.
Bottom life rated good at the inflow and fair at the other three monitoring locations. However, bottom life scored at the low end of the fair range at the forebay and Bear Creek embayment because of higher proportions of tolerant organisms and reduced overall diversity. The lower scores likely were the result of the low dissolved oxygen conditions that developed along the reservoir bottom in 2012.
Sediment quality rated fair at the three locations monitored. Low levels of PCBs were detected in samples from each location. Sediment quality has rated good in Pickwick Reservoir most years. Exceptions were fair ratings at the mid-reservoir in 1993, the forebay in 1996 and all monitoring locations in 1998 due to the detection of low levels of pesticides (DDT/DDD or chlordane) in the sediments.
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 Tennessee Wildlife Resource Agency's Web page and the Epidemiology Division of Alabama Department of Public Health’s Web page.