Oroville crisis drives harder look at aging US dams

SAN FRANCISCO » One year after the worst structural failures at a major U.S. dam in a generation, federal regulators who oversee California’s half-century-old, towering Oroville Dam say they are looking hard at how they overlooked its built-in weaknesses for decades.

The Federal Energy Regulatory Commission is telling owners of the 1,700 other hydroelectric dams it regulates nationally that it expects them to look equally hard at their own organizations and aging dams, in the wake of the sudden collapse of much of first one, then both spillways last February at the 770-foot-tall (235-meter-tall) Oroville Dam, the nation’s tallest.

Given that the average dam in the United States is in its 50s, like Oroville, it’s critical that owners and monitors of America’s 90,580 dams act on a main lesson of the near-disaster, dam officials nationally say: Is the way a dam was built in the Cold War-era or earlier good enough to protect lives in 2018 and beyond?

The crisis in California, a state that had been recognized nationally for its damsafety program, “makes very clear that just because a project has operated successfully for a long period of time, does not guarantee that it will continue to do so,” the federal dam regulators wrote late last month in an unusual, blunt open letter to U.S. dam operators.

“We are focusing on how to improve our program to identify and prevent incidents, regardless of magnitude, that could result from similar dam safety and organizational factors that contributed to the Oroville incident,” regulators wrote. “We expect our regulated dam owners to have similar internal discussions.”

Last Feb. 12, residents across parts of three counties in the Sierra Nevada foothills fled their homes. Authorities warned the chain reaction of structural failures at the Oroville Dam complex could send a wall of water gushing through their nearby Gold Rush-era towns within the hour.

Despite evacuation orders for nearly 200,000 people, however, the feared uncontrolled release of massive amounts of Oroville’s reservoir did not happen. California’s repair bills for the neardisaster have neared $1 billion. Residents downstream have filed more than $1 billion more in claims.

Last month, two national dam-safety organizations focused the blame on the dam’s overseers. California’s Department of Water Resources, which owns Oroville; regulators; and consultants had focused on satisfying routine regulatory requirements for the dam — which anchors a water system that supplies more than half of California’s people — but never took stock of whether the dam complex was built well enough in the 1960s to stand up over time, their independent probe concluded.

Oroville shows “we got a little complacent with what we were doing” as an industry, “and now need to re-examine and identify some of the more subtle and latent problems,” John France, a Colorado-based dams expert who led the probe, says now.

California’s Department of Water Resources declined to make an official available to comment for this article, but said in an email it is implementing changes called for by France’s team.