New Map Identifies U.S. Rivers Most in Need of Protection
Researchers have produced the first comprehensive map showing which U.S. rivers are both healthy and protected, revealing that only a small fraction meet both criteria.
A team of scientists spent four years assessing the health of rivers and streams across the contiguous United States, rating each watershed on connectivity, floodplain quality, water availability and flow changes. By combining these metrics with 91 prior assessments of freshwater biodiversity, they produced the most detailed map to date of river resilience. The findings show that merely 6 % of river miles are both healthy and formally protected, whereas about 13 % are in good shape but unprotected, leaving them vulnerable.
Healthy, resilient rivers cluster in the Pacific Northwest, northern Rockies and the Southeast, while the most at-risk systems lie in the Southwest deserts, Great Plains and southern New England. The study suggests that targeted actions—such as dam removals on stretches like the Klamath River or preserving long unbroken sections like the Delaware River—could yield outsized benefits. Experts say the map can guide future conservation funding and policy decisions as climate change intensifies pressures on freshwater ecosystems.
