Decision to repair dam puts quake study on hold.

Byline: Matt Cooper The Register-Guard

The decision to fast-track repair of the failing Fern Ridge Dam means delaying work on readiness for another potential disaster there: earthquakes.

The U.S. Army Corps of Engineers decided recently to postpone study of the dam's vulnerability to earthquakes, so that the more immediate threat - a possible break in the dam due to internal erosion - can be fixed by the end of the year, project manager Mark Dasso said. All staff and money earmarked for the earthquake study has been redirected to the erosion problem.

Fern Ridge is no different from the corps' other 12 dams in the Willamette Valley: The agency can't say how any of them would fare in an earthquake because there's no money to complete the studies, spokesman Matt Rabe said.

That's partly because when crises such as the internal erosion at Fern Ridge emerge, the corps diverts money from other uses and projects - such as earthquake study - to solve the problem quickly.

If Fern Ridge is ultimately found to be vulnerable to earthquakes, the cost to retrofit the dam could be more expensive than if the work is done while fixing the drainage system, Dasso said.

But that's a big "if," he added. Moreover, the study would not be finished for three to five years and the failing dam would have to be kept out of commission throughout - and that's a high cost to local users, Dasso said. When the dam is out of commission, the water level in the reservoir must be kept low.

The dam provides irrigation to 10,000 farmland acres and generates $8.5 million annually in recreation tourism.

`If you look at just repair cost alone, it's more expensive in two costs,' Dasso said. `If you look at all the benefits (of the dam), this is a better way to go.'

The repair of the drainage system will be done in such a way as to accommodate any later retrofitting of the dam for earthquakes, he added.

John Falk, dam safety coordinator with the Oregon Department of Water Resources, agreed with the corps' decision. His office and the corps share responsibility for dam safety.

`Not that (earthquake studies) aren't important,' Falk said, "but if you've got a leaky roof, you better get that fixed before you decide what color of wallpaper you want to put in the kitchen."

But Jay Wilson, tsunami and earthquake coordinator for the Oregon Office of Emergency Management, said it's critical to assess the safety of dams.

"We may be sitting with a certain false sense of security or safety because we don't have a repeated interval of even low-level earthquakes that cause us to act on what should be ongoing seismic safety programs," he said.

As recently as 1993, the state endured two "mid-level" earthquakes, one that damaged the state Capitol in Salem and another that damaged brick buildings in Klamath Falls.

On the other hand, it's been 300 years since Oregon endured an earthquake on a scale of the one in December that caused the fatal tsunami in southern Asia.

But there's another way to look at that number, Wilson said: Given that these earthquakes strike on an average of every 500 years or so, Oregon is more than halfway to the next one.