Slowly – but surely – we are learning that the near-catastrophic failure of Oroville Dam’s main spillway wasn’t truly caused by weather, even though the state claims that in seeking federal aid for repairs.
Rather, it resulted from poor engineering and construction when the nation’s highest dam was rising more than a half-century ago as the centerpiece of the State Water Project, and poor maintenance since its completion.
The latest evidence is a huge report by a team of engineering experts, headed by Robert Bea and Tony Johnson of the University of California’s Center for Catastrophic Risk Management.
It concluded that the dam’s fundamental flaws were compounded by decades of neglect by the state Department of Water Resources (DWR) and the Division of Safety of Dams (DSOD).
“The gated spillway was managed to failure by DWR and DSOD,” the damning – no pun intended – report declared.
One of the most abysmal failures cited was “the recently exposed existence of DSOD inspection reports dating back to 1989. For reasons yet to be fully determined, identified deficiencies were either ignored, treated as low priority, not acted upon or a combination thereof.”
The 124-page report added that “complacency, lack of industry standard level maintenance, and possibly pressure from internal DWR management and external State Water Contractors’ representatives to hold down maintenance costs were key contributors.”
Finally, and most ominously, the study team suggested that Oroville’s problems are not confined to the spillway, whose collapse last February led to the near-failure of an auxiliary spillway, a threat of failure in the dam itself, and massive evacuations of those living along the Feather River north of Sacramento.
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