The ecological health of Boone Reservoir rated “fair” in 2016. Ecological conditions in Boone Reservoir were assessed a “poor” rating in all previous years except 2015, when it also rated “fair”. The most notable results for 2015 and 2016 were improved dissolved oxygen concentrations at the South Fork Holston mid-reservoir monitoring location (see discussion below). Throughout the years, each indicator at all sampling locations has exhibited some stress: high concentrations of chlorophyll, low dissolved oxygen concentrations, “fair” fish assemblage, “poor” bottom life, and elevated concentrations of metals and/or the presence of organic contaminants in the sediments.
TVA monitors three locations on Boone Reservoir — the deep, still water near the dam, called the forebay (South Fork Holston River Mile 19.0), and two mid-reservoir locations (South Fork Holston River Mile 27.0 and Watauga River Mile 6.5).
In October 2014, a small sinkhole and seepage was discovered at the base of the dam that indicates a potential risk to the integrity of a section of the dam’s earthen embankment. After extensive investigation, TVA developed a proposal to remediate the seepage. The project began in early 2016. TVA has lowered the reservoir pool elevation to between approximately 1,350 and 1,355 feet (about 10 feet below winter pool levels) as a precaution to minimize threats to public safety. The lower pool elevation will be maintained during the project period (5 to 7 years). Learn more about the Boone Dam Project.
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>72 = Good
59-72 = Fair
<59 = Poor
|Mid-reservoir (South Holston)||Good||Poor||Fair||Fair||Fair|
|Mid-reservoir (Watauga River)||Good||Poor||Fair||Fair||Fair|
Dissolved oxygen rated “fair” at the forebay and “good” at both mid-reservoir monitoring locations. Dissolved oxygen conditions have varied considerably from year-to-year and from sit-to-site but generally rate “poor” at the forebay and South Fork Holston mid-reservoir locations and “good” at the Watauga River mid-reservoir location. Low dissolved oxygen concentrations typically develop in a portion of the lower water column during summer at each location. However, at the Watauga River mid-reservoir site, low dissolved oxygen exists only for a short time, and the total area of the water column affected typically remains small enough that conditions are assessed a “good” rating.
Prevailing weather patterns and the related changes in reservoir flows are a major factor in differing dissolved oxygen conditions from year-to-year. During 2015 and 2016, however, the improved dissolved oxygen conditions at the South Fork Holston mid-reservoir location were likely due to the lower pool elevations which reduced reservoir volume and shortened the length of time water remained in this reach of the reservoir.
As part of TVA’s Reservoir Release Improvement Program in the late 1990s, TVA installed auto-venting systems in the turbines at Boone Dam to improve the quality of water released from the dam. Aerating turbines use low-pressure areas to draw air into the turbine area as power is generated.
Chlorophyll concentrations were elevated at all monitoring locations, resulting in a “poor” rating. High chlorophyll concentrations are a common problem on Boone, typically rating “poor” or at the low end of the “fair” range.
As in previous years, the fish community rated “fair” at all three monitoring locations. Characteristics of the fish communities (e.g., fish abundance, species richness and composition) were similar to long-term averages for the respective sampling locations. A moderate number of fish and fish species were collected at each location, with composition being dominated by a few species such as bluegill, gizzard shad and spotfin shiner. Fish health was assessed a “good” rating with low incidences of disease and parasites.
Bottom life rated “fair” at all three monitoring locations. Benthic organisms consisted mostly of midges, worms, and small mollusks known as fingernail clams. Bottom life generally rates “poor” or at the low end of the “fair” range due to the limited variety of organisms collected.
Sediment quality rated “good” at the forebay monitoring location because no PCBs or pesticides were detected, and concentrations of metals were within expected background levels. Sediment quality rated “fair” at the South Fork Holston and Watauga River mid-reservoir locations. Low levels of PCBs were detected in the sediments collected from South Fork Holston mid-reservoir and the concentration of copper was slightly above suggested background levels in the Watauga River mid-reservoir sample.
Problems with organic contaminants have persisted over the years as chlordane and PCBs are sometimes detected in the sediment samples from each monitoring location. Additionally, elevated levels of copper and zinc are sometimes present in the sediment samples from the Watauga River mid-reservoir location. These metals (copper and zinc) naturally occur in soils but can also originate from many sources. Their concentrations in sediments deposited in the reservoir are generally near—slightly above or slightly below—suggested background concentrations.
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 Boone Reservoir, visit the Tennessee Wildlife Resource Agency.