Bracing for the Big One: Oregon dams, roads and bridges at risk

Bracing for the Big One: Oregon dams, roads and bridges at risk

EUGENE, Ore. - There are 2,500 bridges, thousands of miles of roads and six major highways in the state of Oregon.

When The Big One hits - a 9.0 earthquake that experts say is in the Northwest's future - much of that infrastructure will break.

"There will be failures, there will be some roads that are impassable," said Rick Little with the Oregon Department of Transportation.

A study ODOT did two years ago with Portland State University found crucial roads like Highway 101 would crumble.

"You would see at least five bridge failures," Little said. "You would see more than 30 bridges suffer extensive damage."

Major roads connecting the coast to Interstate 5 would give way, and landslides could block others.

"Every east-west route from 101 to I-5 would also suffer some extensive damage," Little said. "There would be pockets of population centers that could very well be isolated for a period of time."

Local dams like Lookout Point and Dexter could fracture.

"It could be as significant as some cracking along the crest of the dam," said Jeremy Britton with the U.S. Army Corps of Engineers.

Worst case scenario: water spills over the dams, causing major floods.

Britton said seismic studies are done on Oregon dams every 15 years, but many of the state's dams, built decades ago, aren't up to modern standards.

"We're looking at now, ground motions that are two or three times higher than what the dams were designed for," Britton said.

"We can't say with certainty," Britton said, "that the dam is going to perform as it was intended to."
One thing that is certain: a major earthquake will put Oregon's infrastructure to the test.