Upper Midwest Ecoregion - National Rivers and Streams Assessment Results
NRSA 2018-19 Ecoregional Results
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Key Results
An estimated 98,752 stream miles in the Upper Midwest ecoregion are represented in the National Rivers and Streams Assessment (NRSA).
- In the Upper Midwest ecoregion, biological condition was good in 36% of stream miles based on macroinvertebrates.
- The most widespread stressors assessed were phosphorus, nitrogen and riparian vegetation cover with 51%, 47% and 24% of river and stream miles in poor condition respectively.
- 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 19% of river and stream miles and no miles were above EPA’s criterion recommendation in the Upper Midwest ecoregion.
Change from 2013-14*
- The percent of river and stream miles in good condition for phosphorus increased by 14 percentage points between 2013-14 and 2018-19 in the Upper Midwest ecoregion.
- The percent of river and stream miles with microcystin detections decreased by 21 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.
