The National Hydropower Association in April presented Snohomish County PUD with its annual Outstanding Stewards of America’s Waters Award. The award recognizes the PUD’s recently completed Water Temperature Conditioning Project at Culmback Dam, designed to improve habitat for salmon and other aquatic life in the Sultan River downstream of the Spada Lake Reservoir.
As part of its relicensing requirement for the Henry M. Jackson Hydroelectric Project, the PUD was tasked with warming the river below the dam to better reflect the river’s seasonal temperature differences. Prior to the project, water released into the Sultan River came from the base of the reservoir, which is naturally colder than water near the top. By contrast, a nearby intake tower allows water used for electricity to be drawn from near the reservoir’s surface, which is warmer.
PUD engineers designed a 715-foot-long solution. A new pipeline now diverts some of the warmer water flowing through the intake tower and power tunnel to the base of the dam where it mixes with the cold water. The result is a steady flow of water in the Sultan River with temperatures better suited to support future fish populations.
“These improvements will stimulate productivity, improve growth, expand distribution and add resiliency to the fish population, allowing salmon and others to thrive in the Sultan River prior to their migration to Puget Sound,” says Keith Binkley, PUD Natural Resources Manager.
The water temperature conditioning project follows a related 2016 PUD project that reopened a six-mile stretch of the Sultan River to migratory fish. Salmon were discovered in the newly reopened stretch within weeks, proof of the project’s immediate success. The 2016 efforts also earned praise and a national award from the NHA.
In March of this year, PUD biologists observed a healthy level of juvenile salmon making their way out of the river and toward Puget Sound, an encouraging sign the PUD’s efforts continue to have a positive environmental impact.