In aquatic ecology, the term "thermal refuge" refers to a cold or warm area in which organisms are protected from unfavorable water temperatures.
Since the release of the Environmental Protection Agency (EPA) guidance for temperature water quality standards in 2003, Oregon and Washington have adopted the standards for waters designated to protect coldwater salmonids. USGS and EPA co-authors published a basic guide for identifying coldwater refuges in rivers and streams of the Pacific Northwest. The guide provides an overview of cold-water refuges in river systems for the protection of salmon and trout. It also provides instruction on what cold-water refuges are, how to identify them, how they function, and how they can be protected and restored. It is a summary of the current science and intended to assist Pacific Northwest tribes, states, and local groups to implement the water quality temperature standards for protecting and restoring coldwater habitats for salmonids.
Torgersen, C.E., Ebersole, J.L., Keenan, D.M., 2012, Primer for Identifying Cold-Water Refuges to Protect and Restore Thermal Diversity in Riverine Landscapes: U.S. Environmental Protection Agency EPA 910-C-12-001, p. 91.