Snohomish PUD Fish Passage Helps Species, Adds 6-Miles of New Habitat
New salmon redds or spawning nests have popped up in the Sultan River in Washington after the Snohomish County Public Utility District constructed a new passage for fish at its Diversion Dam. The new spawning nests were spotted more than five miles upstream from the dam, which signifies that the project was a success.
Snohomish PUD was recognized by the National Hydropower Association for its work on the fish passage project. The utility was designated at 2017 Outstanding Steward of America’s Waters for recreational, environmental and historical enhancement. The designation is given to projects that provided enhanced recreational opportunities for the general public, offer measurable benefits that mitigate, conserve, preserve or enhance the natural resources, or conserve historical aspects of hydropower facilities and their integration with the surrounding community.
“Access to additional habitat benefits the population by giving fish more options across the landscape,” said Keith Binkley, Natural Resources Manager for Snohomish PUD. “More options adds resiliency to the population in the same way that variable run timing does. The combination of spatial and temporal variability allows the species to ‘weather the storm’ when necessary to ensure persistence.”
Snohomish PUD worked with community stakeholders to construct what’s called volitional fish passage at the Diversion Dam. The dam is part of the Jackson Hydroelectric Project which provides 5 percent of Snohomish PUD’s power as well as water to the city of Everett and incidental flood control. It was issued its initial Federal Energy Regulatory Commission license in 1961. The improved fish access was required in settlement that came with a new FERC license for the project, which was issued in 2011.
“Implementing the license for the Jackson Hydropower Project has been a collaborative endeavor between Snohomish PUD and settlement parties for the new license for this project,” said Thomas O’Keefe, chair of the Hydropower Reform Coalition. “This project is a showcase example of what we can do working together to improve the health of a river while still continuing to locally generate hydropower that benefits our communities and reduces our carbon footprint.”
Snohomish PUD completed the fish passage improvements in December 2016. Construction required the utility to cut through a manmade structure and excavated down to create access to natural habitat upstream for fish. This makes the structure itself pretty unique.
“Fish passage at the Diversion Dam is essentially an open garage door — the door is left in the open position allowing for an unimpeded passage way through the dam,” Dawn Presler, Sr. Environmental Coordinator said. “The channel elevation at the gate location was cut down to the river’s historic bottom elevation, allowing the river to flow through the open gate along its natural grade. There is no artificial difference in elevation as fish migrate up or down the stream and through the dam.”
The improvement allows fish to access an additional six miles of habitat that have not been accessible since 1930 when the dam was built. A high-resolution underwater sonar system is also installed at the passage to enumerate salmon and steelhead as they pass upstream during their spawning seasons. The sonar system will provide information to allow Snohomish PUD to adaptively manage its operations to tailor minimum stream flows, control water temperature and time the process flow releases based on fish passing through the system.
“Providing access to historical spawning and rearing habitat upstream of the Diversion Dam is expected to increase salmon and steelhead production in the Sultan River by allowing these species to fully utilize available habitat and potential production capacity,” said the settlement parties in the FERC license agreement. “The reintroduction of [these fish] to this reach is also expected to benefit resident rainbow trout and other aquatic and terrestrial species by increasing primary productivity through the addition of marine derived nutrients.”
The project is not only saving fish populations — its inventive design saved the utility and its ratepayers money as compared to a traditional fish passage structure. What could have ultimately cost $4 million to complete, the selected design saved roughly $1.5M in construction and $30K per year in ongoing maintenance.
In addition, one cost-saving measure Snohomish employed was to avoid purchasing fish screens. Snohomish PUD developed an inexpensive back-up plan to prevent ESA listed fish species from entering the city of Everett’s water supply system by temporarily using screens from another one of its dams. Thanks to measures like these the project was completed under budget and ahead of schedule. Since the project saw success within just one week of opening, it eliminated the need to fund the planting of new fish in the waterway, for savings of about another $1.5 million over the term of the license.
“NHA is thrilled to present Snohomish PUD with the OSAW Award for Environmental Enhancement,” said Linda Church Ciocci, NHA’s Executive Director. “Snohomish PUD has been a leader in environmental stewardship, and their volitional fish passage is a shining and innovative example of how the hydropower industry works to protect and preserve the rivers that provide clean, sustainable energy.”