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Public works: Infrastructure


Photo courtesy of WACA
More than 2,000 cubic yards of concrete were cast in place for a fish trap on the Baker River.

Adult fish trap and juvenile fish stress relief ponde

Location: Concrete, Skagit County

Owner/developer: Puget Sound Energy

Project team: CDM, general and concrete contractor; R3 Resource Consultants, structural engineer; Concrete Nor’West, read-mix supplier




Puget Sound Energy’s adult fish trap facility, a component of Baker River Hydroelectric Project, was designed to improve conditions for native salmonids returning for spawning.

More than 2,000 cubic yards of concrete were cast in place for multiple specialty applications, ranging from 18-inch retaining walls along the riverside to a concrete ogee with a supersmooth finish for releasing juvenile fish into the rapid current of the Baker River.

An essential requirement for the health of the fish is that all surfaces must be smooth and durable. There are no non-metal materials that can replace concrete in these stringent fisheries applications.

Significant work was conducted on the river shoreline. The water-quality effects of the releases into the river had to be minimized. The versatility of modern mix design and admixtures, such as high-range water reducers and anti-washout admixtures, allowed the contractor to tremie concrete into the downstream cofferdam. Quick set was critical with negligible increases in pH intrusion into the river, demonstrating concrete’s compatibility with the environment in riverside applications.

Because the facility must last for at least 50 years, concrete was selected for its fish-friendly surfaces, compatibility with the high-energy and water-quality conditions of the site, and its structural strength and durability.



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