Apalachia Reservoir received a “fair” ecological health rating in 2021. The reservoir has scored either “good” or “fair” since the first assessment in 1997. Apalachia received its lowest scores in 1998 and 1999. This was largely the result of lower scores for bottom life.
The ecological health of Apalachia Reservoir has been monitored using the same methodology since 1997. Ecological health evaluations focus on five indicators: dissolved oxygen, chlorophyll, sediment quality, benthic macroinvertebrate community (bottom life), and fish assemblage. TVA monitors one location on Apalachia Reservoir, the forebay (Hiwassee River Mile 67.0), near the dam.
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>72 = Good
59-72 = Fair
<59 = Poor
*Sediment quality was assessed a “good” rating based on monitoring results from 1997 through 2018.
Dissolved oxygen rated “fair” in Apalachia because concentrations were low in a small area along the bottom in late summer. TVA has found low dissolved oxygen concentrations in this same area each year of sampling.
Chlorophyll concentrations were slightly above the expected range, resulting in a “fair” rating. Chlorophyll ratings have fluctuated between “good” and “fair,” with no specific trend through time.It should be noted that chlorophyll concentrations in Apalachia Reservoir are assessed relative to expectations for the Blue Ridge Ecoregion, which has naturally low nutrient concentrations. Therefore, chlorophyll concentrations are expected to be much lower in Apalachia than in other Tennessee Valley reservoirs located outside the Blue Ridge Ecoregion.
The fish community in Apalachia rated “fair” because relatively few fish were collected. That meant lower ratings for some of the characteristics used to evaluate the fish community, particularly fish density and diversity. Redbreast sunfish, bluegill, and spotted bass were the predominant species observed. Fish health was assessed a “good” rating with low incidences of disease and parasites.
Because Apalachia Reservoir is a small, deep, cold-water reservoir, this tends to limit the warm-water fish assemblage. Consequently, the North Carolina Wildlife Resource Commission has been conducting a pilot project since 2012, managing Apalachia as a trophy trout fishery.
In 2021, bottom life rated “fair”. This compares to “poor” and “low-fair” ratings in years prior to 2000, and “good” ratings from 2000 through 2018. The “fair” rating in 2021 resulted from a slight decrease in the density and diversity of organisms in the samples collected; however, bottom life scored at the upper end of the “fair” range in 2021.
Sediment quality was assessed a “good” rating based on monitoring results from 1997 through 2018. Sediment samples were not collected from Apalachia Reservoir in 2021. Sediment quality typically rates “good” for Apalachia, as was the case in 2018, when sediment samples were last collected. A “good” rating means no PCBs or pesticides were detected, and concentrations of metals were within suggested background levels. Sediment quality rated “fair” in 2000, 2012, and 2015. In 2000, the sediment sample had slightly elevated concentrations of copper, probably related to the area’s geology. In 2012 and 2015, low levels of PCBs were detected.
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 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 Apalachia Reservoir, visit the Occupational and Environmental Epidemiology Branch, N.C. Division of Public Health.