Ecological Health Rating
The overall ecological health condition of Beech Reservoir rated “fair” in 2021. The reservoir has scored within the “poor” range most years. Consistent problems have been elevated chlorophyll concentrations and low dissolved oxygen concentrations near the bottom. In addition, one or more contaminants often are present in the sediments. The higher ecological health scores (“fair”) in 2012, 2015, and 2021 were primarily the result of improved chlorophyll concentrations. The score of 42 in 2000 was the lowest recorded for Beech Reservoir. This was the result of several indicators concurrently scoring at the low end of their historical range rather than a substantial change in any one indicator.
The ecological health of Beech 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 fish assemblage. TVA monitors one location on Beech Reservoir — the deep, still water near the dam, called the forebay.
Ecological Health Ratings for Beech Reservoir 1994-2021
To view or export the data, click on the menu in the top-right corner of the chart.
>72 = Good
59-72 = Fair
<59 = Poor
Ecological Health Indicators for Beech Reservoir - 2012
*Sediment quality was assessed a “fair” rating based on monitoring results from 1994 through 2018.
As in previous years, dissolved oxygen rated poor. Oxygen concentrations were low (<2 mg/L) in the lower third of the water column from May through August, with periods of time when the bottom water was completely devoid of oxygen.
Chlorophyll concentrations in 2021 were slightly above the expected range, resulting in a “fair” rating for this indicator. High chlorophyll concentrations have been a problem in Beech Reservoir, typically resulting in “poor” ratings. However, chlorophyll also rated “fair” in 2018, and “good” in 2012 and 2015.
The fish community in 2021 rated “fair”. A moderate number of fish and fish species were collected. The most abundant species were bluegill, largemouth bass and yellow perch. However, tolerant individuals, which includes bluegill and largemouth bass, and non-native individuals, which includes yellow perch, each comprised a larger proportion of the population than expected and contributed to the overall “fair” rating for the fish community. Fish health was assessed a “good” rating with low incidences of disease and parasites.
Bottom life in 2021 rated “good”. As in most years, the organisms collected consisted mostly of midges and worms. Bottom life in Beech usually rates “good” compared to other reservoirs in the Tennessee Valley’s Interior Plateau ecoregion.
Sediment samples were not collected from Beech Reservoir in 2021. Sediment quality was assessed a “fair” rating based on monitoring results from 1994 through 2018. Sediment quality typically rates “fair” for Beech, as was the case in 2018, when sediment samples were last collected. In 2018, Sediment quality rated “fair” because samples contained concentrations of arsenic that were above suggested background levels; no pesticides or PCBs were detected. Sediment quality has rated “fair” most years due to arsenic. However, in 2012, samples also contained detectable levels of PCBs and DDE (a breakdown product of the pesticide DDT).
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 Beech Reservoir, visit the Tennessee Wildlife Resource Agency.