2005: Flood control at St. Helens criticized

The Army Corps of Engineers spent millions to control water and debris after Mount St. Helens erupted. It helped prevent floods but altered natural habitats.

May 12, 2010 

After Mount St. Helens erupted in 1980, the mountain of rubble left at the foot of the mountain looked like another disaster waiting to happen.

A 17-mile long heap of volcanic ash, mud and pulverized rock - some 3 billion cubic yards of it - sat steaming in the headwaters of the Toutle River, apparently poised to wash downstream.

Concerns about blocked river channels and flooding convinced President Ronald Reagan to declare an emergency. He turned the Army Corps of Engineers loose, dredging rivers, digging drainage channels and building roads, levees and debris dams.

At the time, with the volcano just having turned 234 square miles of forest and river valley into a wasteland and flooding a real threat, worries about the environmental effects of the corps' work seemed frivolous.

Now, however, the long-term impacts of some of the corps multimillion-dollar solutions have become subjects of strong criticism.

Twenty-five years after the eruption, as one of the corps' biggest fix-it projects approaches the end of its usefulness, environmentalists are urging the agency to rethink its priorities and come up with more natural solutions.

"The corps went up there and did exactly what it wanted to do," said Mark Smith, whose family operated a lodge at Spirit Lake before the eruption. "They never listened to the local people.

"Now, what they should be saying is, 'Here's what we did 20 years ago. Is it still the best thing we should be doing today?' "

An unprecedented problem

The corps is proud of its St. Helens projects. The tasks it faced in 1980 were extraordinary and unprecedented. There were no off-the shelf solutions, said John Etzel, the corps' current manager of Mount St. Helens sediment control projects.

"We were under an emergency situation, and we didn't have a lot of volcanic sedimentation history to tap, even worldwide," Etzel said.

"In the '80s," he said, "when the eruption occurred, the first order of business was to open those rivers up and get the level of flood protection up."

Mud flows had rushed down the Toutle and Cowlitz rivers all the way to the Columbia, where they stranded ocean going freighters in the Port of Portland.

The corps dredged enough volcanic material out of river channels to have built a 12-lane freeway, a foot thick, all the way from St. Helens to New York City.

The rubble in the upper valley blocked the natural outlets of Spirit Lake, the former site of youth camps and vacation cabins.

With no outlet, water in the lake increased rapidly. If the lake were to break through the debris flow, hydrologists warned, a torrent twice the size of the Columbia River would flood down the tiny Toutle valley, wiping out Interstate 5 and possibly the Port of Longview.

To keep Spirit Lake at what it calculated was a safe level, the corps drilled a tunnel, 11 feet in diameter, through 1.6 miles of rock. The $13.5 million tunnel diverted lake water away what would have become its natural course - through the debris flow.

To keep sediment from moving downstream and refilling river channels, the corps blasted a settlement basin in the North Fork of the Toutle valley and blocked the river's flow with a sedimentation dam, 184 feet tall and 1,800 feel long. The dam slows the water long enough for sediments to drop out.

Both projects worked as planned. Spirit Lake stayed in place; rivers did not flood. Millions of cubic yards of soil that would have continued on down the North Fork of the Toutle River stayed in the upper valley.

But the consequences have been considerable, say environmentalists, scientists and natural resource managers.

Difficult solutions

Since 1987, when the $65 million sediment retention structure began operating, the barren mud plain that has backed up behind it has grown to 2,400 acres.

The structure dramatically changed the natural hydrology of the area, said Fred Dobler, the state Department of Fish and Wildlife's program manager for the region that includes St. Helens.

"The sedimentation retention structure backed up material in a broad, highly erodible plain," Dobler said. "Instead of a single stream bed forming in the upper valley, shallow streams tend to meander through the mud plain, constantly changing course.

"Every time the streams change course they wash more material away. That inhibits the formation of soil. Nothing grows there."

Because the corps diverted the outflow from Spirit Lake through the tunnel, migrating fish have no access to the lake and the tributaries above it, as they did before the eruption.

Repeated aerial seeding of grass on the mudflow created temporary meadows, which initially encouraged an unnaturally large elk herd. But despite repeated reseeding, the grass never took hold in a sustainable way, and hundreds of elk starved as the food supply dropped.

Salmon no longer can make their natural passage up and down the North Fork of the Toutle. Fish migrating up the river are trapped, then hauled in trucks around the sedimentation structure.

Fish can't be released into the main fork of the river but must be taken to tributaries, said Wolf Dammers, the state fish biologist for the St. Helens area.

"If we released them into main Toutle, with all those multiple streams, they might never find those tributaries," he said.

From a fisheries standpoint alone, it would have been better to let the river recover from the volcano on its own, Dammers said, but concerns about flooding and sedimentation made that impossible. Now, he said, the fish are paying the price.

"The habitat will probably never recover with that dam in place," he said.

Planning nature's course

Smith, who makes a living leading tourists through the volcanic area, is a relentless critic of the corps' work.

The sea of mud backed up in the upper Toutle River valley is a wasteland, he said, and it breaks his heart to look at it.

"They're destroying habitat daily here," Smith said. "When you walk the banks and you see huge cedar trees and maples 200 to 300 years old dying, it's really hard to take."

Smith thinks the corps overreacted in the 1980s. It should have let the river flow naturally through the upper North Fork. The sedimentation problem eventually would have stabilized on its own, he said.

"Nature would have carved her own course," he said.

The corps is open to other solutions, Etzel said. And, with the sedimentation structure nearing capacity, the corps is in the process of re-examining what to do next, perhaps raising the height of the structure or building another one somewhere else.

But, practically speaking, he said, the corps' primary missions have not changed.

"Right now, the corps has two authorized missions at Mount St. Helens," he said. "Flood control and navigation. We don't have a mission regarding fish passage and vegetation."

Etzel advised those with concerns to talk to their congressional representatives.

"Let them know the urgency and need for establishing that," he said. "As you know, federal agencies can't move forward without funding and authorization."

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Rob Carson: 253-597-8693

rob.carson@thenewstribune.com

Originally published on May 17, 2005.

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