SEATTLE — Salmon and steelhead could soon reach prime spawning grounds in the upper Green River for the first time in over a century.
The U.S. Senate on Thursday passed the Water Resources Development Act within the annual national defense policy bill, clearing the way for construction to begin on fish passage at the Howard A. Hanson Dam, about 20 miles east of Auburn.
Almost half, or about 100 river and stream miles, of the Green River’s historical Chinook salmon spawning and rearing habitat have been inaccessible since the Tacoma Headworks Diversion Dam went into operation in the 1910s.
The diversion dam, about 3 miles downstream of Howard Hanson, has been upgraded for a trap-and-haul program, allowing adult salmon to be trucked above the dams to the upper watershed once the Howard Hanson fish passage project is complete.
Now this new money will allow outmigrating juvenile fish to pass the dam heading downstream.
The project has the potential to open up more salmon and steelhead habitat than the Elwha River dam removal on the Olympic Peninsula.
“We were listening to groups and organizations who told us it was probably one of the largest gains for potential salmon production in Puget Sound, in the region, in the state, probably even on the West Coast,” U.S. Sen. Maria Cantwell, D-Wash., said earlier this week.
There, in the upper reaches of the Green River, Chinook and coho salmon, and steelhead trout, will lay their eggs. Later, baby fish will emerge and eventually use the new passage to make their way toward estuarine habitat where they will fatten up before heading to the saltwater of the Sound.
The Army Corps plans to construct something called a “fixed multiport collector” in the dam to help move migrating juvenile salmon downstream. The result will likely be five vertically stacked holes, allowing fish to pass at varying reservoir water levels, according to Dallas Edwards, Army Corps spokesperson. The money from Congress will provide for the final design and initial construction costs.
Juvenile salmon migrate near the surface of the water column, which fluctuates in height by as much as 100 feet during spring migration. Collecting fragile baby fish from such a moving target is a big design challenge.
Once the fish make it into the holes, gravity will usher them through pipes and finally into a tunnel that will slowly release them back into the river. Construction is expected to begin in 2027 and take about three years.
Without fish passage, the National Oceanic and Atmospheric Administration found, the dam threatens the survival of endangered Puget Sound Chinook and southern resident killer whales. In 2019, the agency ordered the Army Corps of Engineers to make fish passage operational by 2030.
The fish passage project is just one piece of the Howard A. Hanson Dam additional water storage project. The Corps began construction on the project to create an additional 20,000 acre feet of water storage in 2003. But work on fish passage, originally scheduled for completion in 2006, stopped in 2012 when the design penciled out to more than double the maximum cost limit.
“We built our adult trap-and-haul facility and it became operational in 2007,” said Greg Volkhardt, Tacoma Public Utilities source water and treatment operations manager. “And we’ve just been patiently waiting, working with the Corps of Engineers and our congressional delegation and others to try and get everything in place so that the Corps can be successful in completing the downstream fish passage. So we’re really excited.”
In 2020, all of the state’s congressional members signed a letter insisting the Army Corps make salmon passage at the dam a top priority. Earlier this year, they helped secure $220 million for the initial construction through the Bipartisan Infrastructure Law.
The total project cost, including money already spent on the additional water storage project and initial design, is $921 million, according to an Army Corps spokesperson.
“We’re the ones who screwed this place up,” said Laura Blackmore, executive director of the Puget Sound Partnership.
“We’re the ones who built the dam without fish passage. We’re the ones who put a railroad across all the small streams on the eastern shore of Puget Sound. We’re the ones who built I-5 on the causeway across the Nisqually Delta. We’re the ones who put the Ballard Locks in and created a buffet for the sea lions to come eat all the fish,” she said. “So it’s our responsibility, I feel, to fix our past mistakes.”
The Muckleshoot Tribe has treaty-protected fishing rights on the Green River, which flows into the Duwamish, and has invested heavily in salmon recovery in the watershed.
Restoring access to the Upper Green River has been identified as a critical piece of Puget Sound salmon recovery, and a means of giving a leg up to the southern residents. The scarcity of Chinook, orcas’ primary food source, is one of several factors driving the species to extinction, scientists have determined.
The southern resident orcas are starving, Blackmore said.
“The more we can get them good foods, the better their chances of survival,” she said. “This kind of project is sorely needed.”
The Water Resources Development Act authorized other Army Corps of Engineers projects in Washington, including the Duckabush Estuary restoration, studying flood control, and addressing the effects to Indian villages and housing sites that resulted from construction of multiple dams by the Corps in the Columbia River Basin. The legislation will also create a Puget Sound Recovery office within the Environmental Protection Agency.