Northern Appalachians Ecoregion - National Lakes Assessment Results
Key Results
An estimated 17,550 lakes in the Northern Appalachians ecoregion are represented in the National Lakes Assessment (NLA). Of these lakes, 86% are natural and 14% 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 Northern Appalachians, 5% of lakes are rated as hypereutrophic while 29% are eutrophic, 54% are mesotrophic and 12% are oligotrophic.
- The most widespread stressors assessed are phosphorus, nitrogen and dissolved oxygen with 29%, 27% and 17% 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 2% of lakes and no lakes are above the recreational benchmark.
![Lake in Vermont, Vermont Crew](/system/files/styles/medium/private/images/2022-06/NAP%20VT_NLA_2017%20%285%29.jpg?itok=tHQVUWrF)
Change from 2012*
- For the Northern Appalachians, the NLA reports that the percent of lakes in poor condition for riparian vegetation cover decreased by 16 percentage points between 2012 and 2017.
- The percent of lakes with microcystin detections decreased by 12 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/NAP_2017%20Good.png?itok=iyDmrsvz)