Freshwater rivers provide essential ecosystem services, including drinking water supply, hydropower generation, flood mitigation, and recreation. Despite their importance, many rivers in the United States lack protections specifically designed for freshwater systems. Instead, river conservation is largely embedded within terrestrial-based protection mechanisms.
Given the complex network of local, state, and federal agencies involved in river management, it remains unclear how effective these overlapping protections are when considered together. This raises a fundamental question: how well are U.S. freshwater rivers actually protected?
Comte, L., Olden, J.D., Littlefield, C., Dickson, B.G., Zablocki, J. and Moryc, D. 2026. National assessment of river protection in the United States. Nature Sustainability. DOI: 10.1038/s41893-025-01693-8.
Recent research addresses this question by evaluating the full suite of protection mechanisms applied to rivers nationwide and integrating them into a single protection index. The index is based on five key ecological attributes: hydrologic regime, connectivity, water quality, habitat condition, and biotic composition. Using this framework, researchers classified river protection into four categories (comprehensive, effective, limited, and inadequate), allowing them to identify both protection gaps and areas with high potential for future conservation or restoration.
The analysis shows that while nearly half (47%) of protected river lengths are covered by more than one protection mechanism, almost two-thirds (64%) of the 7 million km of rivers in the U.S. remain unprotected. This figure increases to 70% when considering only the contiguous U.S.
Protection is also unevenly distributed, with strong geographic and ecological biases. Rivers in Alaska, polar regions, and temperate coastal areas are more likely to be protected than those in the central and southeastern U.S., such as the Mississippi River Basin and Texas–Gulf region. Rivers that are larger, perennial, high-elevation, and/or colder receive more protection than smaller streams, headwaters, intermittent rivers, and lowland or warmer systems.
Administrative boundaries strongly influence protection outcomes. Of all protected river lengths, 23% fall under state-level protection and 74% under federal mechanisms. However, most states protect less than 10% of their total river length at a viable level, and protection is highly inconsistent for rivers that cross state boundaries. In addition, most watersheds are inadequately protected, although 13% do exhibit high potential for restoration.
Overall, the study finds that only 12% of river length in the contiguous United States (and 19% nationwide) is protected at a level likely to sustain ecological integrity. Because most existing protections are terrestrial in nature, the findings highlight the need to better integrate freshwater systems into large-scale conservation initiatives like 30×30.
Given the inherently connected nature of river networks and the concentration of headwaters across administrative boundaries, effective river conservation will require coordinated, cross-boundary approaches. This assessment provides a valuable framework for summarizing river protections and guiding future efforts to sustain freshwater biodiversity and ecosystem services.
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