Despite the rush job -- "it was like a war zone" with more than 160 construction workers working overtime -- the dike was built "to perfection," Wettanen said.

BIGGER FLOODS COULD COME

Chris Waythomas, an Alaska Volcano Observatory hydrologist, said two big floods in the current eruption are comparable to the biggest ones 19 years ago, when output of the Drift River exceeded that of the Yukon.

"These flows are moving large boulders of ice, 30 to 50 tons. It's really an impressive scale of flooding," Waythomas said.

And there's still plenty of ice left -- 20 to 30 percent of what was originally on the mountain when it started erupting March 22, Waythomas said. While the volcano has been quiet since its largest explosion of the current string, on April 4, it's building a massive dome that could collapse or explode and generate another flood.

Nye, the state geologist, said the previous three eruptions are small compared to recent prehistory. About 3,000 years ago, a massive eruption created Crescent Lake on the south side of Redoubt.

"That was a much bigger deal than anything that's come down the Drift River in historic times," Nye said.

"The dikes that are out there obviously were tall enough, but just barely, that they didn't get overtopped this year," Nye said. What would happen if the next blast from Redoubt was as big an explosion as could be expected every thousand years, not every 20, Nye wondered.

"This whole thing, you're playing with probabilities -- the numeric probabilities of a bad situation you're willing to accept," Nye said. But there's been little public discussion about how the risks were calculated at Drift River, he said.

"I haven't heard the discussion about the level of volcanic hazard people are living with," he said.

NATIONAL SECURITY?

When Redoubt, with its then-untested dike, began to rumble in January, scientists at the Alaska Volcano Observatory warned an eruption was possible. Shavelson, of Cook Inletkeeper, asked Cook Inlet Pipe Line, the Coast Guard and the Alaska Department of Environmental Conservation for a report on the amount of oil stored. That number would tell whether nearby clean-up equipment was up to the task, he said.

He was told the information was a homeland security secret. Reporters got the same response.

Shavelson said he suspected the company just didn't want to reveal the risks to the public. It wasn't until the eruption started and the facility was abandoned out of fears for worker safety that Cook Inlet Pipe Line disclosed the tanks held 6.2 million gallons.

There's evidence to support Shavelson's suspicion that the company's concern about disclosure wasn't out of fear of terrorist attack. Despite the dangerous levels of oil in its tanks, the facility didn't have a single closed-circuit camera to monitor what was happening after the workers left. Francis, the Coast Guard spokeswoman, said cameras were finally installed two weeks ago, enabling real-time remote monitoring of access points and other areas of security interest at the facility.

LIMITED OPTIONS

Drift River would have been unnecessary if a large-enough pipeline had been laid across Cook Inlet.

Rod Ficken, Cook Inlet Pipe Line Co. vice president, said such a project would have been a huge technological challenge in the 1960s, given the Inlet's ferocious tides and deep shipping channel. Divers report boulders the size of cars routinely roll along the bottom.

A former producer, Amoco, built a 10-inch pipeline across the Inlet from platforms near Trading Bay, but it failed repeatedly and was abandoned in 1977. Years later, it began burping residual oil, leading to a clean up by BP, the successor to Amoco, in 2002 that was expected to cost up to $7 million.

Rick Kuprewicz, an oil-facility consultant in Redmond, Wash., said pipeline technology has come a long way since the 1960s, but the small volume of production now would probably not justify such a project.

Kuprewicz, who's familiar with Drift River from his days as an Arco official on the Kenai Peninsula, said oil companies "get kind of crazy about cost reductions" when fields begin to reach the end of their lives.

"You have to spend money to ensure oil stays under control," Kuprewicz said, noting that a spill could pollute the entrance to the Kenai River.

Shortly after the first Redoubt explosions this year, officials said they couldn't easily drain the tanks because the pump intakes sat several feet above the bottom of the storage tanks.

Kuprewicz said it may be possible to construct new defenses by modifying the terminal and tanks, such as a self-draining bottom that would enable them to be speedily emptied.

"There's always more than one solution," Kuprewicz said.

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Find Richard Mauer online at adn.com/contact/rmauer or call 257-4345.

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