Northwest residents are surrounded by thousands of dams, some in a state of disrepair. And now the emergency at California’s Oroville Dam has sharpened interest in dam safety.
In King County, Washington, this week, officials are reevaluating their downstream evacuation plans. Washington state watches more than 1,000 big, non-federal dams. Of those, just 427 dams with significant populations downstream, are inspected every five years.
In Oregon, there are 15,000 dams. The state watches over 900. Right now, the state has seven dams on its “unsatisfactory” list. Every year Oregon engineers visit 75 high-hazard dams — dams with large populations downstream. They visit the rest of the lower-hazard dams once every two-to-three years.
Jonathan Garton is the president elect of the Association of State Dam Safety Officials. He said budgets are always tight.
“It’s always more glamorous to construct new infrastructure, something to point at,” Garton said. “It’s always harder to fund and justify ongoing repair and maintenance.”
The last dam failure in Washington happened in Okanogan County in 2014. A combo punch of wildfire stripped landscape and heavy rain storms eroded the spillway.
In Hermiston, Oregon, a major Simplot company lagoon spilled 95 million gallons of water in 2005 with running mud over a large swath of land and a highway.
When it comes to problems with major dams in the Northwest, Washington’s Wanapum Dam on the Columbia River developed a major crack in its spillway in 2014. The dam’s 800-foot-long spillway section wasn’t anchored to bedrock during construction. Crews have since sutured the dam back together.