Water & Drought

State water officials were warned of Oroville Dam weakness a dozen years ago

As California officials rushed Monday to stabilize conditions at Oroville Dam, the state’s top water official brushed aside questions about recommendations made a dozen years ago to upgrade the emergency spillway that nearly failed Sunday.

In a Monday afternoon news conference near Oroville Dam, Acting Department of Water Resources Director Bill Croyle was asked whether the spillway should have been reinforced years ago as advocacy groups advised in 2005 filings with the federal government.

Croyle said he wasn’t familiar with the reports, but that once the crisis subsided, engineers would do a thorough analysis of what went wrong.

“That’s part of our vetting process,” he said.

The recommendations to strengthen the spillway came as state officials were seeking approval from the Federal Energy Regulatory Commission to relicense Oroville Dam for another 50 years.

Advocacy groups including Sacramento-based Friends of the River said at the time that the emergency spillway would actually pose a danger if the reservoir were hit with heavy storm runoff from the Sierra Nevada and filled to the brim.

The groups said the emergency spillway needed to be strengthened to avoid almost precisely the events that occurred this weekend, when the spillway activated and the forested hillside below began eroding dangerously close to the lip of structure.

“As I recall, effectively (the official) response was ‘Well, you know, it doesn’t seem likely we’d ever have to use the emergency spillway,’” Ron Stork, a senior policy advocate at Friends of the River, told The Sacramento Bee.

Stork’s group advocated for the changes along with officials in Yuba and Sutter counties downstream from the dam. At the time, state officials objected to upgrading the spillway, saying it wasn’t necessary.

“Our facilities, including the spillway, are safe during any conceivable flood event,” Raphael Torres, acting deputy director of the State Water Project, told The Bee in 2005.

The spillway issue dates to 1970, when the operational manual for the dam was updated with the expectation that Marysville dam would be built on the Yuba River, a tributary of the Feather. This new dam was authorized by Congress in 1966, but never was built.

Nevertheless, Oroville operations were designed to work in concert with the Marysville dam to ensure Feather River flows would not exceed the holding capacity of downstream levees.

Croyle said Monday that second-guessing decisions of his predecessors may come later.

“We’re going to get into recommendations or concerns that were voiced in the past,” he told reporters Monday. “But right now, we’re focused on maintaining public safety – not strictly during this event, but also this spring runoff period.”

Sam Stanton: 916-321-1091, @StantonSam

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