U.S. Army Corps of Engineers officials awarded a $657 million contract to build a fish passage facility at Howard A. Hanson Dam on the Green River to Flatiron-Aecon Joint Venture.
Flatiron is based in Colorado with numerous offices, including a Renton location. Aecon is a Toronto, Ontario-based company with numerous offices, including one in Lynnwood. Army Corps officials awarded the contract Oct. 16.
The contract method is innovative and allows collaboration between designers and the contractor during project’s design phase, according to an Army Corps press release.
After design is completed, construction is scheduled to start in 2026 and the facility will be finished in 2030, according to an Army Corps spokesperson in the Seattle District office.
“We are excited to support salmon and Orca recovery with our tribal partners, federal and state agencies, and our non-federal sponsor Tacoma Public Utilities to ensure completion of this downstream fish passage facility and support the regional water supply,” said Col. Kathryn Sanborn, Army Corps Seattle District commander.
Tacoma Public Utilities has already completed an upstream fish passage facility that is ready for operation. Once the downstream facility is operational, the two facilities will restore the biological connection of the upper watershed (45% of total area) to the lower watershed via salmon migration.
The project will provide over 100 miles of high-quality river and tributary habitat. The project will increase the ability of Endangered Species Act for listed Chinook salmon to access substantially more spawning and rearing area — 221 square miles of undeveloped watershed, according to the press release.
Hanson Dam is an earthen dam on the Green River.
Hanson Dam was built to protect the people and infrastructure of the Green River Valley from historical catastrophic flooding, including the cities of Renton, Tukwila, Kent and Auburn. The dam has prevented an estimated $23 billion in flood damage since its completion in 1962, according to the Army Corps.
The dam includes other benefits such as providing clean drinking water to the people of Tacoma, Kent, Covington, and other areas, fish conservation and ecosystem restoration.
The Army Corps initially started to look at building a fish-passage tower along the Green River in the late 1990s to be completed by 2007. But bids came in higher than the government estimated and were not awarded. Dollars also became tight because the Corps spent so much money on recovery efforts after Hurricane Katrina struck the Gulf Coast in 2005.
The Army Corps looked again in 2009 at building a fish passage facility with an estimated cost of $220 million. But that project never received funding and in 2011 was suspended because it exceeded costs, according to the Corps.
Congress approved funding in 2023 for the current project.
