Seattle trying to woo salmon back downtown with park's seawall makeover
Two centuries ago, tiny chinook leaving the Duwamish River could head north and find refuge in a chain of salt marshes and shallow beaches.
Today, their descendants face a much more treacherous path to adulthood.
Pioneer Square and Interbay occupy what once were salt marshes, drained and filled by settlers. Warehouses and pavement cover the Duwamish mudflats. The concrete seawall protecting downtown Seattle from Puget Sound creates a sheer drop into deep water, where little fish find less food and more waiting predators.
Now, the city, state and developers are working to soften Seattle's treatment of the imperiled salmon. Planners envision a rebuilt 1.3-mile seawall covered with massive knobby panels that create better fish habitat. In the future, retooled piers near the Seattle Aquarium and the downtown ferry dock could feature engineered, shallow fish habitat.
The Seattle Art Museum's new Olympic Sculpture Park, on downtown's north end, offers a glimpse into the future.
Waves wash up on a small gravel beach, made to mimic the beaches that once lined Elliott Bay. A manmade underwater plateau of rock and sand slopes out from an 850-foot-long section of the seawall. It provides shallower, food-rich terrain for the salmon.
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"I think the [sculpture park] seawall is kind of a harbinger of things to come as far as making the central waterfront a better habitat, given what it is: It's a working waterfront," said David Graves, a senior planner at the city's parks and recreation department.
Scientists want to know if the revamped waterfront along the edge of the sculpture park can really help revive such an industrialized area. Environmentalists and the museum hope it captures people's imagination with a new model of how the city meets the Sound.
A former eyesore
The newfound status of the sculpture-park site as an environmental showcase is a striking reversal from its previous life as a toxic headache.
For decades beginning in the early 1900s, the waterfront land between Broad and Bay streets was home to a major fuel transfer station, covered with huge storage tanks and pipelines. By 1975, when the station closed, leaks had soaked the soil and groundwater with petroleum.
In the ensuing cleanup in the 1990s, the station owner, Unocal, dug up 117,000 tons of contaminated dirt and sucked more than 4,000 gallons of petroleum from tainted groundwater.
When Martha Wyckoff saw the site in 1996, it was a massive, dug-up piece of ground, surrounded by chain-link fences. Wyckoff, a board member for The Trust for Public Land, a land conservation group, was looking for a future park and home to public art. The group helped broker the deal enabling the Seattle Art Museum to buy the land.
"It was muddy and dirty and looking very lonesome. But it had an amazing quality of being at the water's edge," she said. "And now it is truly an extraordinary park."
No one suggests the waterfront will return to its natural state. That would mean digging up the viaduct, piers, roads and railroad tracks that sit on dirt dumped over tidelands.
When white settlers first arrived here, the gravel beach that lined much of Seattle's waterfront sloped gently into the water, offering a convenient highway for young salmon making their way to sea.
Today, those chinook are protected under the Endangered Species Act.
Rather than return to nature, scientists and engineers hope to imitate it.
A year ago, at the sculpture park, they used a crane to lower 50,000 tons of rock into the water along the seawall, creating a habitat "bench" 15 to 20 feet wide. At low tide, this faux-tideland sometimes lies out of the water.
The rock work has the dual benefit of creating habitat and shoring up the seawall for tens of millions of dollars less than other construction methods. Work on the seawall and beach cost $5.7 million, much of it from the city, state and federal agencies.
Twelve months later, algae is taking root. That suggests it will become a better home for the little crustaceans and worms that juvenile chinook eat, said Jason Toft of the University of Washington's Wetland Ecosystem Team.
But a big question remains: How well will it work?
Toft hopes to get some answers this spring and summer, when he will snorkel the waters there counting and measuring fish and the animals they eat.
Remaking the piers
A similar shallow-water bench would appear around the Seattle Aquarium as part of a Seattle Department of Parks and Recreation plan.
The department wants to redesign several big, decaying piers there. Plans call for creating the shallow areas and moving piers away from the seawall. Narrow ramps would connect the seawall to the piers, letting more light reach the water. Added light helps sea plants grow and could attract young salmon.
The plan, which could cost as much as $30 million, is scheduled to go to the City Council by this spring for approval. If endorsed, it could be finished by 2010, said Graves, of the Parks Department.
Farther south, the state's ferry system is considering similar features for an overhaul of the downtown terminals at Colman Dock.
Then there's the challenge of making a vertical seawall offer some of the same habitat as a sloping beach.
John Arnesen of the city's transportation department is counting on massive 30-square-foot knobby concrete panels to cover the smooth seawall. The panels would be studded with rocks or other protrusions designed to give sea plants a place to grow and small fish a place to swim.
Arnesen wants to start testing different designs in the water. These panels could become part of the larger seawall project.
But that's years away, and it's still not clear who will pay for the $800 million replacement of the aging seawall, which could be finished by 2015.
Still, the waterfront's ecosystem is already getting better, as seen through the scuba mask of Don Weitkamp, a fisheries scientist and consultant.
Weitkamp points out that some piers have been removed over the years, or rebuilt using fewer pilings. Clean sediments cover contaminated soil, keeping pollution from leaking out. Concrete pilings have replaced toxic creosote-soaked wooden pilings.
With the new projects, Weitkamp sees a broader commitment to the waterfront.
"People are now looking at what can we do to make it better," he said. "It's more purpose-driven now."
Warren Cornwall: 206-464-2311 or firstname.lastname@example.org
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