Tellico Reservoir

Dissolved oxygen

Dissolved oxygen rated good at the mid-reservoir location and poor at the forebay due to low concentrations (less than two miligrams per liter) in the lower water column throughout summer. Historically, dissolved oxygen ratings at the forebay have fluctuated between good, fair, and poor. Weather conditions and related changes in reservoir flows are a major factor in the differences that arise from year to year. Dissolved oxygen has consistently rated good at the mid-reservoir location.

Chlorophyll

Chlorophyll rated poor at the forebay and fair at the mid-reservoir location. Higher chlorophyll levels can be expected at the forebay monitoring location because of the exchange of water from the chlorophyll-rich forebay of Fort Loudoun Reservoir via the canal connecting the two reservoirs. However, concentrations were higher than expected at the mid-reservoir location given the nutrient-poor soils in the upstream watershed. Chlorophyll typically rates poor at the forebay and fair or poor at the mid-reservoir location.

Fish

The fish community rated good at both monitoring locations. This indicator typically rates fair in Tellico Reservoir, but it has occasionally rated good. Monitoring usually shows moderate to good species diversity, but the number of fish collected each year has been lower than expected.

Bottom life

As in previous years, bottom life rated poor at both monitoring locations because few animals were found and most were capable of tolerating poor conditions. Low dissolved oxygen levels and cold bottom water are likely contributing factors.

Sediment

Sediment quality rated fair at both monitoring locations because PCBs were detected and arsenic concentrations were slightly above suggested background levels. Sediment quality rated good in most previous years, but the detection of pesticides (chlordane and aldrin) and/or elevated levels of arsenic have resulted in some fair ratings. Arsenic naturally occurs in the soils and concentrations in sediments deposited in the reservoir are generally near – slightly above or below – suggested background concentrations. The pesticides that were detected in Tellico Reservoir were banned from use in the 1970’s and 1980’s. However, they continue to be detected sporadically in sediments because of their persistence in the environment.

See definitions of ecological health indicators and monitoring locations.