Northern Appalachians Ecoregion - National Rivers and Streams Assessment Results

Key Results

An estimated 124,198 river and stream miles are represented in the Northern Appalachians ecoregion in the National Rivers and Streams Assessment (NRSA). 

• In the Northern Appalachians ecoregion, biological condition was good in 27% of river and stream miles based on benthic macroinvertebrates and 38% good for fish.
• The most widespread stressors assessed in the Northern Appalachians ecoregion were nitrogen with 42% of river and stream miles in poor condition, phosphorus with 39% of miles in poor condition, and riparian vegetation cover with 39% of miles in poor condition. 
• Cyanobacteria are photosynthetic microorganisms that  occur at low levels. Under the right conditions (elevated nutrients and increasing temperature), cyanobacteria can grow at elevated rates producing blooms. 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.
  • Microcystins detections occurred in 3% of river and stream miles and no miles were above EPA’s criterion recommendation in the Northern Appalachians ecoregion.

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Change from 2013-14*

• The percent of river and stream miles in good condition for phosphorus increased by 25 percentage points between 2013-14 and 2018-19 in the Northern Appalachians ecoregion.
• The percent of river and stream miles with microcystins detections decreased by 30 percentage points.

To access more ecoregional specific information, please visit the interactive NRSA Dashboard.

* The change analysis is based on information from two points in time – 2013-14 and 2018-19.