EPA National Rivers and Streams Assessment: Water Condition Trends

2018-19 survey data shows the percentage of U.S. river and stream miles in poor condition, with change analyses comparing to the 2008-09 and 2013-14 surveys. Condition is assessed for indicators including nitrogen, phosphorus, biological metrics, acidification, salinity, and human health contaminants like microcystins. All results are presented with 95% confidence intervals, using NRSA-specific regional or national benchmarks.

Use Cases

• Tracking national trends in river and stream health based on biological and physical indicators.
• Assessing regional water quality against EPA benchmarks for nutrients like nitrogen and phosphorus.
• Evaluating human health risks from contaminants such as enterococci and cyanotoxins (microcystins, cylindrospermopsin).
• Comparing water condition changes between the 2008-09, 2013-14, and 2018-19 survey periods.

Strengths

• Data originates from the authoritative U.S. EPA National Rivers and Streams Assessment.
• Provides multi-year trend analysis across three survey cycles (2008-09, 2013-14, 2018-19).
• Results include statistical confidence intervals calculated at a 95% confidence level.

Limitations

• Specific column names, row counts, and file formats are not provided in the source metadata.
• License information and precise data size are unknown.
• The dataset appears to be an extracted dashboard export, not the underlying raw survey data.

Provenance

Source

United States Environmental Protection Agency (EPA)

Collection Method

Exports from the interactive National Rivers and Streams Assessment Dashboard.

Time Range

2008-09 to 2018-19

Freshness

Last updated on 2026-04-21, though this likely reflects a metadata update rather than new survey data.

Geography

United States (national scale)