The Green River, which supplies much of Tacoma’s drinking water on its journey from the Cascade Mountains into Puget Sound via Seattle (where it becomes the Duwamish), has been named one of America’s most endangered rivers by a national environmental group.
American Rivers, a nonprofit based in Washington, D.C., designated the Green-Duwamish as endangered because the group considers 2016 a critical point for the river. It cites key decision points in the near future: adding a fish passage to the Howard A. Hanson Dam and improving local communities’ floodplain and pollution management.
The agency’s annual listing has never before identified the Green-Duwamish River as among the country’s most endangered, although the list has included one or more Washington state rivers at least 10 times since the early 1990s.
Michael Garrity, American Rivers’ director for the rivers of Puget Sound and the Columbia Basin, said several state rivers that appeared on the endangered list in previous years had benefited from policy decisions that came in the wake of the listings. Among the improvements, he said, were removals of dams on the Elwha River (listed in 1992 and 1995) and the commitment to build a Mud Mountain Dam fish passage on the White River (listed in 2014).
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This year’s report highlights the plight of the salmon and steelhead populations as barometers of the Green-Duwamish River’s health. Both, it says, have suffered from development along the river. Levees tightly confine the lower river’s floodplain, holding back floodwaters for development but also creating a fast-flowing stream with little shade where fish cannot thrive. Urban and industrial uses along the river’s Duwamish segment have streamed unhealthy chemicals into the river via runoff.
And then, Garrity said, there are yet-to-be calculated consequences of drawing off a much larger amount of river flow than Tacoma currently takes, to feed a proposed methanol plant in the Tideflats.
“That Green River water supply needs to be carefully stewarded by Tacoma,” he said, “and that (proposal) is using a big part of what the city can draw.”
Already, the river’s fish population is in measurable distress, the report says. Recent years’ counts have found as few as 800 Chinook salmon returning annually, and the rate of returning adult salmon for the last 40 years has averaged less than 10 percent of the historic annual average of 38,000. The Howard Hanson dam, completed in 1962 to hold back the frequent flooding in the Green River valley and named after a Seattle attorney and politician, is a barrier to the fish at the same time it protects human residents.
The forested area above the dam, a 30-mile stretch of river, is salmon-spawning territory; before the dam, juveniles could hatch, swim away and return upriver as fertile adults. Howard Hanson Dam lacks a fish passage, constraining the populations on both sides. A second dam, the Tacoma Headworks Diversion Dam, has been engineered to allow adult salmon and steelhead to pass through to the upriver area, but that’s not enough help if juveniles can’t get downstream, the report says.
It advocates a proposed U.S. Army Corps of Engineers project to put a juvenile fish passage on the Howard Hanson Dam to enable more fish to travel the circuitous routes their ancestors swam for centuries. The motive isn’t simply being nice to the fish for the sake of it. Laws protecting the endangered Chinook salmon and steelhead trout populations in the river could be triggered if their numbers don’t turn around. Doing that, Garrity said, would put new restrictions on river water use.
“If they’re not doing enough to restore threatened salmon,” Garrity said, “then it puts more pressure, potentially, to do more or to use less water out of the Green River.”
The report contains a simple recommendation with a host of real-world complications. If two federal agencies — Army Corps of Engineers and the National Oceanic and Atmospheric Administration — agree on a plan to complete the fish passage this year, the report says, the project could be done by 2021. The NOAA has advocated for the passage since 2001, the report says, so the deal would seem halfway done already.
However, Daniel Johnson, the U.S. Army Corps of Engineers’ operations manager for Howard Hanson and Mud Mountain Dams, said the idea of opening a fish passage in five years “would be a very idealistic schedule,” considering the obstacles in play.
Between the congressional budgeting cycle, design work that hasn’t begun, and then a two-year construction process, Johnson estimated the project’s requirements at seven years and “at least in the realm of $100 million” that has not yet been appropriated.
“It’s going to take a lot of time, and it’s going to take a significant amount of money,” he said.
He said the listing of the river as endangered tends to increase public awareness and, therefore, political will for the big-money decisions that large, river-improving projects require, as happened with the White River’s proposed Mud Mountain Dam passage.
“We’re at a point now where we’re putting together what is really, truly required, considering all these changes, so we can put together a new request to go to Congress,” Johnson said.
What will happen in Washington, D.C., remains unclear.
“I want our children and grandchildren to enjoy everything Washington State has to offer,” said U.S. Rep. Dave Reichert, R-Auburn, whose district includes the Howard Hanson Dam. “This includes preserving the state’s natural gems. Maintaining healthy fish passage and river habitat is important to the conservation of our region.
“In pursuing this goal, we must keep in mind the reality of budget constraints and consider which projects will have the greatest impact when choosing where to focus our funds. I am hopeful that development of new technologies and new approaches will ultimately lower the costs of these efforts.”
The other potential improvements highlighted by the report are less sharply defined recommendations to improve pollution and floodplain management. Along the 12-mile Duwamish portion of the river — until the last century, the stretch where the White, Green and Black rivers flowed together into Elliott Bay — a nearly $350 million cleanup is in the early years of a long process. Upstream, where levees have tightened the river to stave off floods and allow open land to be turned residential, the report now calls for levees pushed farther back and a new buffer of shade trees along the waterway.
Without those changes, Garrity said, fish will continue to languish, and the projected more intense rains of climate change will surmount the levees where they now stand along the Green River.
“It has controlled flooding pretty well,” Garrity said of the levee system, “but it also created this ability and sort of false security for communities in the valley that they could develop the floodplain without worrying about the effect on public safety or the environment.”