Corps of Engineers wants trees removed near levees, clashing with salmon advocates

For decades, King County and the U.S. Army Corps of Engineers have fought over the trees and thick brush that grow along the levees of area rivers.

The county and federal fisheries managers want the streamside greenery to stay in place to keep waters cool and shady for threatened salmon. The Corps often wants the bigger trees removed, arguing they destabilize the levees and increase the odds of flooding.

Now a shift in this simmering battle could have huge implications for endangered fish and the people who live and work behind levee systems like those along the Green River in Kent.

The Corps has proposed further limiting levee vegetation and is considering making it harder to get around those requirements. And it's doing so just as the Federal Emergency Management Agency (FEMA) redraws floodplain maps.

That combination, say local officials and members of Washington's congressional delegation, could limit development in some places and boost flood-insurance rates for thousands of homeowners and businesses around Puget Sound.

"This thing has been coming to a head for a while," said Michael Mactutis, an environmental engineer with the city of Kent. "And nobody really knows where it's going to end up. But it's frustrating for everyone."

Before recent problems with Howard Hanson Dam, most of Green River Valley, for example, was not considered part of a floodplain because the river is surrounded by levees. But, in the future, FEMA is moving to treat river valleys as floodplains unless levees are shown to be certified as meeting Corps standards.

And the Corps has proposed so seriously clamping down on how much vegetation it allows on levees that many major levee systems would struggle to get certified even after the levees have been beefed up. Yet much of the vegetation is there at the urging of federal agencies to help endangered bull trout, steelhead and chinook.

"The Corps' proposal just seems to be heading in the opposite direction that everyone around here thinks we should go," said Jan Hasselman, an environmental attorney. "It solidifies a rigid rule prohibiting most vegetation and creates an extremely onerous process to have any ability to get around that."

Current Corps national policy limits trees on levees to 2 inches in diameter. In the Northwest, the agency allows those trees to be double that width.

But the Corps' new draft plans would virtually ban all trees on levees and make it extremely hard for regions like the Northwest to get around the rules.

"The primary challenge is, how do you provide a policy that can protect the public, along with the resource needs and habitat needs," said Doug Wade, with the Corps in Washington, D.C. "This policy is intended to craft a balance between those."

Cities and counties, state agencies, tribes and environmentalists all condemned the Corps' draft plan. Last week, five members of Congress and both of Washington's U.S. senators sent the Corps a letter arguing its proposal was in conflict with so many other federal policies it is driving floodplain managers to confusion and could result in higher insurance premiums for entire communities.

Steve Bleifuhs, who oversees floodplain issues for King County, said the Corps' draft approach also ignores a growing body of evidence that trees and vegetation, particularly in places like the Northwest, can actually strengthen — not weaken — levees. Tree roots can form anchors that work like rebar in rocky levees, helping to keep them stable.

"We've done 220 or 225 repair projects on levees in recent years," he said. "None of them have been because of the vegetation."

Wade said it's far too soon to know how the Corps' plans will shake out. Corps employees are still reading comments from around the country.

Meanwhile, members of Congress have called on the Corps to hold a months-long series of workshops like the Corps has done in California to find a workable solution to levee management in the Northwest. No formal word has come from the Corps, though there have been indications the agency might be amenable to that approach.

Craig Welch: 206-464-2093 or cwelch@seattletimes.com