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Water Clarity

While Tellico Reservoir enjoys pristine nearby mountain headwaters, long-term residents report that the color of the reservoir has developed a green tint over time, particularly during summer months, raising questions about the water quality.

The clarity of water is easily measured using a secchi disk by measuring the depth of light penetration through the water. TVA has been measuring water clarity for 20 years at two locations in the lake. Unfortunately, the trend analysis is inconclusive because the TVA measurements have been infrequent and are not controlled for external factors such as heavy rainfall. 

WATeR made a detailed study of water clarity in 2017-2020, with much more frequent measurements in more locations. The result of this study provided trophic assessments of various locations in the lake, and it confirmed the influence of rainfall and other factors on clarity measures. 


The Trophic State of Tellico Reservoir in 2020

These studies also pointed to the need for undertaking a more detailed study of the algae and nutrients present in the lake, and a proposal was made in 2021:

Proposed Monitoring Plan by Bill Waldrop


In 2022 WATeR entered a study partner relationship with the University of Tennessee Department of Microbiology headed by Dr. Stephen Wilhelm, PhD, to study the presence of Algae in the Reservoir.  We are also investigating methods for implementing long-term monitoring of lake temperatures. The results of the 2022 algae sampling are now published. Read them here.  The study showed that algae was present in the lake, but not a current danger. The water is "healthy" in terms of algae concentrations. The study on algae levels will continue in 2023.

The 2023 report has now been completed and you can read the results here.

Watch this video about algae in the lake

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