US EPA National Rivers and Streams Assessment

Written by Dr. Amy Rosemond, University of Georgia

The EPA recently published its 2013-2014 assessment on national rivers and streams. The majority of U.S. streams and rivers are in fair to poor condition and non-point source pollution is worsening.

We are fortunate that the US EPA, with states and tribes, conducts National Aquatic Resource Surveys (NARS) to assess the condition of coasts, lakes, rivers and streams, and wetlands approximately every five years.  The NARS takes a huge amount of effort and helps us understand the condition of aquatic resources in the U.S. and how they are changing over time.

Image: NSRA 2013-2014

The distinct efforts in assessing condition in these water bodies includes the National Lakes Assessment (NLA), National Coastal Condition Assessment (NCCA), National Wetland Condition Assessment (NWCA), and the National Rivers and Streams Assessment (NRSA).

The most recent NRSA was completed in December 2020 and summarizes data collected from 2013-2014 from almost 2000 river and stream sites around the U.S. Data and trends can be compared to sampling that occurred in 2008-2009. 

Image: NSRA 2013-2014

The findings from the most recent study and the temporal trends in condition are worrisome. The report shows that non-point source nutrient pollution is widespread.  The findings indicate that greater control of nutrient pollutions is needed, in terms of best practices, policies, and other innovations.  The current strategies and practices that are in place are leading to degradation of the nation’s rivers and streams. 

Image: NSRA 2013-2014

Most streams and rivers are only in fair to poor condition as indicated by the biota they support; bioindicators include both macroinvertebrates and fish.  Forty-four percent of US streams are considered in poor condition as indicated by macroinvertbrates and 37% are considered poor based on fish.   

Image: NSRA 2013-2014

Excess nutrients are a real problem in streams, and concentrations are increasing.  Phosphorus is in excess (i.e., rated poor) in 58% and nitrogen in is excess in 43% of streams sampled. These values are up since the last study was conducted. 

In Southern Appalachians streams, even larger percentages of streams were considered poor in regards to excess phosphorus (80%), and excess nitrogen (45%).  Mercury, another non-point source pollutant, was found in excess of fish tissue-based water quality criterion in 24% of sites sampled.

Image: NSRA 2013-2014

All of the information on NARS may be found here https://www.epa.gov/national-aquatic-resource-surveys. The most recent NRSA may be found here https://www.epa.gov/national-aquatic-resource-surveys/national-rivers-and-streams-assessment-2013-2014-report