Why Does It Matter?
Cool water is in short supply in the lower Yakima River and cool water (68 ˚F or colder) is required by species like Sockeye and summer Chinook as they finish their already perilous journey to their spawning grounds. The Lower Yakima River, from Prosser to the Tri-cities typically exceeds this temperature from June through August of each year.
Assessment and Project Development
Mid-Columbia Fisheries and a team of partners are exploring how to capitalize on cool water returning to the Yakima river from irrigation returns and groundwater flows for the benefit of migrating salmonids. With the help of the Benton Conservation District, the Yakama Nation, US Geologic Survey, and other partners, we are collecting summer water surface temperature using drones fitted with forward-looking infrared (FLIR) cameras, maintaining continuous temperature monitoring at 15 locations in the 107-mile reach from Yakima to the Tri Cities, and evaluating two sites we have found with much cooler water for potential restoration.
Developing these projects is a bit of an experiment as we are not sure how fish will use these “Rest Stops” along the way to their spawning grounds. To assess their utility to migrating salmonids fish monitoring is also taking place to guide these experimental projects.
The Benefits
Thermal refuge sites along the lower Yakima River may aid migration and growth of salmonids. They can provide enhanced areas of habitat on the lower Yakima River where extreme summer temperatures can be limiting, especially in low water years. They may also provide high quality rearing habitat for juvenile salmonids during winter months.
