OROVILLE, Calif. — State officials charged with managing Oroville Dam created an unprecedented evacuation emergency last February in part by ignoring the advice of technical experts and trying to avoid flooding a powerhouse, an independent investigator concluded in a scathing report released Friday morning.
The Independent Forensic Team Report, after an investigation that stretched through most of last year, also found that the California Department of Water Resources suffers from a bureaucratic, insular culture that hasn't matured to prioritize safety, and that the result has been, in part, a failure to learn from the latest advances in the industry.
"Like many other large dam owners, DWR has been somewhat overconfident and complacent regarding the integrity of its civil infrastructure and has tended to emphasize shorter-term operational considerations," the report said. "Combined with cost pressures, this resulted in strained internal relationships and inadequate priority for dam safety."
But the problems that built up to last February's near-catastrophe also extend all the way back to the construction of Oroville Dam, America's tallest at 742 feet. The spillway cracked almost immediately after construction, the investigators found, but that was never treated as a serious issue.
In addition, they said, dam operators accepted wrong information for decades about the quality of rock beneath the spillway. So they were unprepared for the scale of damage once a slab lifted and water poured into the hole.
The report stops short of laying direct responsibility, however.
"The incident cannot reasonably be 'blamed' mainly on any one individual, group, or organization," the summary says.
In fact, the report's author's issued a stark warning to the entire industry, raising questions for any community downstream of large dams. Many of the Oroville failings apply broadly to dam managers, they wrote.
"The question is whether dam owners, regulators, and other dam safety professionals will recognize that many of these lessons are actually still to be learned. Although the practice of dam safety has certainly improved since the 1970s, the fact that this incident happened to the owner of the tallest dam in the United States, under regulation of a federal agency, with repeated evaluation by reputable outside consultants, in a state with a leading dam safety regulatory program, is a wake-up call for everyone involved in dam safety."
The Independent Forensic Team consists of six experts recommended by the Association of State Dam Safety Officials and the United States Society on Dams. The experts worked under contracts with the state DWR, but, the report says, they acted with complete independence and did not run their findings by DWR for approval before making the report final.
According to a prepared statement by the DWR, the department agreed with the conclusion of the findings, stating that "all dam owners need to reassess current procedures."
“We strongly supported having an independent assessment of the spillway failure and take the findings very seriously,” said DWR Director Grant Davis. “This report is consistent with the independent team's initial technical findings from last May which were fully incorporated in the design of the reconstructed spillways. As we have done in the past, we will carefully assess this report, share it with the entire dam safety community and incorporate the lessons learned going forward to ensure California continues to lead the nation on dam safety.”
DWR officials also stated that the department has already made "significant progress to bolster the dam safety program" by including comprehensive inspections to include "extensive hydrologic, structural a geotechnical work and a thorough investigation of records."
They agreed that the report was a "wake-up call for everyone involved in dam safety."
"During the incident, our sole focus was protecting public safety,” said Joel Ledesma, deputy director of the State Water Project. “DWR supported this independent assessment – so we can learn from the past and continue to improve now and into the future.”
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