Synthesizing the State of Science of Coldwater Refuges in the Willamette River Basin

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Many regulatory, management, and conservation organizations are interested in protecting and increasing coldwater refuges and thermal diversity for Chinook salmon, steelhead, and other natives fishes in the Willamette River basin. This study synthesizes current and emerging science related to coldwater refuges and thermal diversity. It is also develops conceptual frameworks for understanding the variation in coldwater refuges and thermal conditions and how that variation relates to the abundance and composition of the native fish community.

kayaking scientists

USGS staff in the alcove downstream of the confluence of the Santiam and Willamette Rivers (Credit: USGS).

USGS is collaborating with fisheries biologists from the Oregon Department of Fish and Wildlife and scientists from Oregon State University, University of Oregon, and U.S. Corps of Engineers to synthesize the state of the science for thermal diversity and coldwater refuges in the Willamette River Basin. This study builds on prior and ongoing water quality, groundwater, geomorphic studies conducted by the USGS. Main components of this study include:

  1. Collecting and summarizing measurements of water temperature in select tributaries and the Willamette River downstream of Newberg;
  2. Developing a synthesis report that summarizes: A) how geomorphic, hydrologic, and riparian vegetation processes create coldwater refuge; and B) when, where, and how the thermal mosaics and coldwater refuge influence salmon, steelhead, and other native fishes in the Willamette River; and
  3. Sharing findings with diverse stakeholders working to protect and restore coldwater refuge in the Willamette River Basin.

Ultimately, insights from this effort will support strategic coldwater refuge protection and restoration efforts along the Willamette River and its tributaries.