TACOMA WATER DIVERSION DAM, King County — A long-awaited project to unlock more than 100 miles of prime habitat on the Green River and its tributaries for threatened salmon could be moving forward after more than a decade of setbacks.
Sen. Patty Murray, D-WA, toured Tuesday along the river after Congress carved out $190 million last week for a fish passage and water storage project at the Howard A. Hanson Dam. Murray is the vice chair of the Senate’s Appropriations Committee.
The funding was part of a slate of environment spending that was salvaged in congressional appropriations bills after the Trump administration had planned to zero-out $500 million for the dam.
The design of the dam’s updates is nearly complete, and if all goes according to plan, the work could begin this summer and wrap up around 2031, said Michael Costa, senior vice president for Flatiron, one of the construction firms that was awarded a contract for the project design and construction in fall 2024.
The Green River is fed by snow and rain and flows from the Cascades north of Mount Rainier. It provides drinking water for more than half a million King and Pierce county residents and is home to salmon, such as Endangered Species Act-listed Chinook that sustain fisheries, treaty rights and the endangered southern resident orcas.
The river was impeded by the construction of the Tacoma drinking water diversion dam in the 1910s, blocking salmon and steelhead migration. Efforts began a century ago to tame the river’s flooding, and the U.S. Army Corps of Engineers built Howard Hanson, an earthen dam just 3 miles upstream of the drinking water dam in 1962.
Spawning habitat was locked behind the dams. Downstream, the river flows into the Duwamish, a highly industrialized urban waterway and one of the nation’s most polluted. Once-abundant runs of Chinook and other salmon dwindled. Fisheries shuttered.
The Corps began design and construction of fish passage at the dam in 2003. The work was halted in 2011, when the Corps projected spending would balloon past what Congress had authorized.
Meanwhile, Tacoma Water, which operates the diversion dam, built a fish ladder and other facilities to trap and haul adult spawning salmon upstream that came online in 2007.
Ratepayers covered the costs of the roughly $5 million project, which was a requirement of the utility’s habitat conservation plan. It has sat mostly dormant while waiting for federal action upstream.
Ongoing operations of Howard Hanson without fish passage jeopardize the survival of threatened Puget Sound Chinook and endangered southern resident orcas who depend on them. The National Oceanic and Atmospheric Administration, tasked with recovering salmon and the orcas that feed on them, ordered the Army Corps in 2019 to finish the Howard Hanson fish passage facility no later than 2030.
Washington’s congressional delegation in a 2020 letter urged Army Corps and federal Office of Management and Budget leaders to fund and prioritize salmon passage at the dam.
Murray helped secure $220 million for the project in the Bipartisan Infrastructure Law in 2022, and an additional $50 million to help the Corps continue design and award the construction contract in the fiscal year 2024 funding bills.
Under a Biden administration earmark, the project was to receive $500 million in funding in the Corps’ construction budget.
The funding was most recently set to be erased by the Trump administration. Murray said this was part of an attack on blue states, dubbing it “one of the most blatant acts of political thuggery” from an American president in her tenure.
On Tuesday, Tyler Patterson, Tacoma Water’s watershed services manager, led the senator through a tour of the vacant fish passage. When it is operational, salmon will navigate an 18-step ladder and swim into a concrete trap pool, where a metal crowder will nudge the fish down a flume to be sorted and into different holding tanks to be loaded into trucks and driven above Howard Hanson to spawn.
The adult salmon will die after spawning. The eggs they lay in the gravel will hatch and migrate downstream through the planned fish passage at Howard Hanson.
Costa said that without the $190 million secured in Congress, it wasn’t clear if or when the project would reach construction.
Sen. Murray also secured language in the bill to allow the Army Corps to incrementally fund the project.
A contract could be signed early this summer, and construction could begin. In the winter months when the water levels are lower over the next few years, crews will work to add fish passage on the dam’s water intake, Costa said.
After years of waiting for this to be completed, Tacoma Water will also need to upgrade its existing fish passage facility. Tacoma Water will work with the Muckleshoot Indian Tribe, the state of Washington and federal agencies on plans such as which fish they want to haul around the dams.
The Howard Hanson Dam is intended to reduce flood risk in the Green River Valley, where in the past floods were a more regular occurrence. In the 70 years before construction, the valley flooded more than 30 times, heavily damaging lands and buildings.
During its life, the dam had prevented an estimated $23 billion in flood damage, the Army Corps said in 2024.
The University of Washington Climate Impacts Group is finishing up a study on future floods on the Green River. The modeling clearly shows more and bigger floods coming into Howard Hanson dam into the future, Washington state climatologist Guillaume Mauger said.
It appears the dam can help, but downstream flows will likely reach higher levels more often, potentially putting more stress on levees, Mauger said. But the study won’t be the final say on the matter.
Amid December’s atmospheric rivers, the dam stored a record amount of water, according to the Army Corps, preventing an additional 5 feet of floodwater in the Green River at Auburn. That kind of inundation would have overtopped nearly all the levees, according to the Army Corps.
The Green River did blow through the Desimone levee in Tukwila, prompting warning of “life threatening flash flooding” and inundating an industrial area. Crews quickly patched the hole on the levee that had been awaiting repairs for years.
Salmon have suffered the impacts of the habitat loss in the watershed, said Muckleshoot Indian Tribe Chair Jaison Elkins.
The tribe reserved rights to continue to fish in its usual and accustomed areas when it ceded its vast lands. But what good is a treaty right, Elkins said, if there’s no more salmon?
Elders talk of species, like spring Chinook, now functionally extinct in the watershed, Elkins said. Just this year, the tribe’s fall Chinook fishery closed early to ensure that enough salmon could make it back to the spawning grounds.
The tribe has intervened to rescue salmon here — releasing adult hatchery fall Chinook to spawn naturally in the river, bringing in partners to restore habitat and producing a harvestable run of chum, Elkins said.
Securing fish passage is one step toward recovery, but more work remains.
“We have to have salmon to continue our way of life. It’s a keystone species. When they’re not healthy, our people aren’t healthy,” Elkins said in an interview. “I just think that if we could bring the salmon back, we can also thrive as well.”
Material from The Seattle Times archives was included in this story.
