With rising temperatures and a greater demand on water resources, NOAA Fisheries has identified reintroduction, or the intentional movement and release of endangered salmon back into their historical upstream habitat, as the only way to ensure their long-term conservation and recovery. Today, steelhead and two populations of salmon (winter-run and spring-run Chinook) in California’s Central Valley are listed as threatened or endangered under the federal Endangered Species Act. These salmon and steelhead, known as salmonids, require cold water to survive hot summers. Dams block access to historically high quality habitat in high elevation areas, and the only habitat available to these fish is often of poor quality.