Southern Appalachians Ecoregion - National Lakes Assessment Results
Key Results
An estimated 31,910 lakes in the Southern Appalachians ecoregion are represented in the National Lakes Assessment (NLA). Of these lakes, 0% are natural and 100% are man-made.
The NLA uses trophic state as an important indicator of lake condition and assesses the extent of biological condition and key stressors in the nation’s lakes.
- In the Southern Appalachians, 16% of lakes are rated as hypereutrophic while 64% are eutrophic, 9% are mesotrophic and 11% are oligotrophic.
- The most widespread stressors assessed are nitrogen, phosphorus, and atrazine detection with 89%, 77%, and 32% of lakes in poor condition respectively.
- Cyanobacteria are one-celled photosynthetic organisms that normally occur at low levels. Under eutrophic conditions, cyanobacteria can multiply. Not all cyanobacterial blooms are toxic, but some may release toxins, such as microcystins. For information about risks at specific locations, recreational water users should check with state, tribal or local governments.
- Based on microcystins, detections occurred in 10% of lakes and no lakes are above the recreational benchmark.
Change from 2012*
- For the Southern Appalachians, the NLA reports the percent of lakes in good condition based on the benthic macroinvertebrate indicator decreased by 25 percentage points between 2012 and 2017 and the percent of lakes in poor condition based nitrogen increased by 26 percentage points.
- The percent of lakes in good condition for dissolved oxygen decreased by 28 percentage points between 2012 and 2017.
- The percent of lakes with microcystin detections decreased by 22 percentage points.
To access more ecoregional specific information, please visit the interactive NLA Dashboard.
* The change analysis is based on information from two points in time – 2012 and 2017.
![Image showing the dashboard results from the NLA Interactive Dashboard](/system/files/styles/large/private/images/2022-06/SAP_2017_good.png?itok=v6lm2nLn)