Less than six months after near disaster, Oroville Dam is awash in activity. Workers and equipment are racing the calendar, making sure the nation’s tallest earthen dam can’t again reach the brink of catastrophe. But an ongoing forensic examination suggests otherwise. It says other dangers, possibly undermining the dam’s integrity, remain largely unaddressed. NSPR’s Marc Albert has more.
Independent experts officially recruited to study the how and why of what was nearly the nation’s worst infrastructure failure paint a troubling picture.
Robert Bea is cofounder of the Center for Catastrophic Risk Management at UC Berkeley and coauthor of a recently released 124-page draft report.
"We detected a very pervasive set of elements which tell us not only was the primary spillway being neglected, but other components within this complex dam system,” Bea said.
Bea and other researchers found numerous small flaws afflicting the Oroville facility. Anchors holding the spillway’s flood gates in place may be compromised. It is unclear how badly. One of the massive supports for the floodgates has a 14-foot long crack. A spillway gate jammed during a test a decade ago and still awaits rehabilitation. And patches of green grass on the dam’s face suggest the dam itself might be compromised.
Separately, these issues may not be critical. But Bea said, those defects, together with piecemeal repairs and half a century of wear and tear, could interact in unpredictable and catastrophic ways.
“Complex systems fail in complex ways,” he said.
Bea, now 80, had a career building complex systems in the oil industry, then teaching civil engineering and risk management. He’s now well into a third career, examining infrastructure failures, including New Orleans flooding following Katrina, the explosions of the Space Shuttle Columbia and Deepwater Horizon and the sinking of the Exxon Valdez.
The California Department of Water Resources, which operates the dam, maintains that it is safe. DWR spokeswoman Erin Mellon said the green vegetation is caused by annual rainfall and began happening before the reservoir was ever filled.
It is unclear who is correct. Many of the electronic monitors embedded into the dam to detect leakage aren’t working and haven’t been replaced. While DWR says and Bea admits that there are other ways to detect leaks, Bea maintains that the sensors, known as piezometers are critical.
Bea, said he ran into a stone wall trying to gain access to annual inspection reports from before 2008. Reports that could reveal when the monitors started failing. Bea said an engineer at an official meeting at Oroville dam refused to share the reports, telling him,
“I might be a terrorist, hence, he could not supply or give access to that information," Bea said.
Bea and others on his team suspect that the dam’s core has settled at different rates since being built in the 1960s, possibly creating fissures. He said the failure to acknowledge issues and prioritize repairs point toward deeper, philosophical problems.
“It pays to pay attention when something potentially critical to the dam is happening,” he said.
Maintaining risk at an acceptable level, he said, becomes more difficult, complicated and expensive as facilities age.
Bea said there has been a shift in culture within the DWR that has changed its focus over the decades.
“It was not toward more quality, diligence in operations and maintenance and inspections, but to lesser quality,” Bea said.
As both a supplier of water for cities and agriculture, and in charge of flood protection, DWR has a partly conflicted mandate. The department is funded in part by its customers---mainly municipal water utilities and agricultural irrigation districts hundreds of miles to the south. Those districts also weigh in on what DWR spends money on. They opposed and helped block a push by environmental groups to strengthen the emergency spillway a dozen years ago.
Organizational change was among the subjects broached in a report by California’s ‘Little Hoover Commission’ in 2010 which stated that the department’s structure hinders repairs and delays regular maintenance. The report recommended making the State Water Project an independent entity.
James Gallagher, who represents Oroville and much of the North State in the state Assembly, pointed out the contradiction.
“The entity responsible for enforcing and regulating how this dam is operated and maintained, is also the same organization that is operating and maintaining it,” Gallagher said.
Gallagher introduced legislation requiring DWR to inspect major dams annually and to share those reports with the public. The bill was amended last week shifting financial responsibility onto the dam’s owners---theoretically irrigation districts----and away from taxpayers in general. He said it faces little opposition.
“I don’t think anybody should be opposed to improving your procedures so that we’re safer, and to getting better data so that we can make good decisions,” he said.
On Wednesday DWR announced that federal and state regulators have signed off on final replacement plans for both spillways. Officials have vowed that the structure will be operable by Nov. 1, ahead of the rainy season.