Tolerable Risk Vs. Terrible Catastrophe When It Comes To Dams And The Big One

Jul 20, 2012

It's a question all of us face sooner or later: whether to spend a good chunk of money to protect against a catastrophe that has a very low chance of occurring. A workshop that just wrapped up in Corvallis considered that dilemma in the context of Northwest dams and a magnitude 9 earthquake. Correspondent Tom Banse reports.

Oregon, Washington and the federal Bureau of Reclamation have prioritized which dams they're most concerned about in case the Big One hits. For the feds, it's Scoggins Dam, 25 miles west of Portland. Brian Becker is chief of Reclamation's dam safety program. He's concerned the earthen dam could fail in a megaquake.

Becker: "We're in the range where the probability of failure is around one in one thousand to one in ten thousand in any given year.

Banse: "That sounds like a really low risk."

Becker: "It does sound like a very low risk, but..."

But Becker says if the dam gave way, it would have life-threatening consequences for people downstream. So Becker's division is currently analyzing the economics and the options for reinforcing this dam. A handful of municipal and private dam owners on the Oregon Coast, in Western Washington and British Columbia are beginning similar investigations.

Copyright 2012 Northwest Public Radio