Climate Change & Stream Flow for Salmon: Barriers & Opportunities for Adaptation in Washington State

Climate change is altering seasonal streamflow patterns across Washington state, creating new challenges for both water management and salmon populations. A report produced by researchers from Washington State University, the Washington Department of Ecology, and the University of Washington examines how rising temperatures, earlier snowmelt, and changing precipitation patterns are expected to affect rivers and streams throughout the region. These changes are projected to produce lower summer flows, warmer water temperatures, and more frequent winter and spring flooding, all of which can affect salmon migration, spawning success, and habitat availability.

The report identifies five regions in Washington where different combinations of climate impacts are likely to occur and explores how these changes may affect salmon species with different migration and spawning patterns. Because water management in the western United States is governed by the prior appropriation doctrine, adapting water policy to protect both water users and fish populations presents complex legal and institutional challenges. Researchers highlight opportunities to improve adaptive water management through tools such as instream flow rules, trust water rights programs, and more flexible water allocation strategies informed by climate science.

This work was supported by the Washington State Department of Ecology and the USDA National Institute of Food and Agriculture, project #1016467.