This article from the Sacramento Bee makes the point clearly that the states do not have the money or expertise needed to do the job right.
Federal regulators are raising new concerns about the troubled Oroville Dam, telling California officials their recently rebuilt flood-control spillways likely couldn’t handle a mega-flood.
Although the chances of such a disastrous storm are considered extremely unlikely — the magnitude of flooding in the federal warning is far greater than anything ever experienced — national dam safety experts say the Federal Energy Regulatory Commission’s concerns could have costly repercussions for California. The public agencies that store water in Lake Oroville may be forced to spend millions of dollars upgrading the dam.
State dam operators at the Department of Water Resources also could be forced to store less water in the lake to ensure there’s more room to capture flood waters. Lake Oroville, the state’s second largest reservoir, is a key source of drinking and irrigation water for millions of Californians.
The warning came late last month in a letter from FERC. It was sent just as $1.1 billion in repairs are wrapping up on the dam’s two spillways following the February 2017 crisis at the dam that triggered the evacuation of 188,000 people.
The FERC letter shows that the near catastrophe in 2017 has made the federal government less likely to trust the state’s claims that the 50-year-old dam is as safe as it can possibly be, said J. David Rogers, a dam-safety expert at Missouri University of Science and Technology.
“Given that track record, you’ve got to err on the side of what your safety culture is going to be. Are you going to be at the vanguard of safety?” Rogers said. “That’s a big a facility to play with. That’s the highest dam in the United States. You have to be a little more conservative.”
In the 2017 crisis, a massive crater formed in the dam’s main flood-control spillway. To limit it from growing in size, DWR’s dam operators let water flow over the adjacent emergency spillway for the first time since the dam was completed in 1968.
Although the flows were relatively modest, the earthen hillside below the spillway started to wash away. Fearing the concrete spillway would crumble and release a “wall of water,” officials ordered a frantic evacuation of 188,000 Sacramento Valley residents.
In the 21 months since, construction crews have spent $1.1 billion on emergency repairs and rebuilding and upgrading the two battered structures. DWR officials have said they’re confident the rebuilt spillways can handle this winter’s rains.
DWR officials said the work has left the spillways stronger than ever — and capable of withstanding what the U.S. Army Corps of Engineers considers the worst storm that can be reasonably expected. “The newly rebuilt main spillway can easily do this, without using the emergency spillway,” DWR spokeswoman Erin Mellon said in an email.
FERC, though, is warning about damage that could be expected from a “probable maximum flood,” a storm that would be magnitudes greater. In its letter to DWR last month, the federal agency said the hillside beneath the emergency spillway could face “substantial” erosion if such a storm ever hit — and told the state that the structure might need to be fortified….
Critics of the Department of Water Resources also have long complained that state officials have been reluctant to spend the money to upgrade Oroville, and they say those decisions played a key role in the 2017 emergency.
For instance, engineers had known for decades that if water ever spilled over Oroville’s emergency spillway, it would cause serious erosion, possibly compromising the earthen structure that holds back the reservoir and threatening communities downstream.
But California water districts known as the State Water Contractors that helped pay for Oroville resisted calls to armor the structure, which would have required construction outlays in the tens of millions of dollars.
Critics say the FERC letter represents a victory after years of having their concerns brushed aside.
“The handwriting is on the wall that they’re going to have to confront these issues,” said Ron Stork of the Sacramento environmental group Friends of the River, which has criticized safety issues at Oroville. “The contractors are either going to have to pay for a better dam or accept that the dam doesn’t deliver them as much water.”
Jennifer Pierre, general manager of the State Water Contractors, didn’t immediately respond to a request for comment.
Early this year, the independent forensic team led by France heavily criticized California officials, saying the state did a poor job of designing, building and maintaining the structure and neglected safety while focusing on the “water delivery needs” of the water districts who keep water in Oroville.
The forensic team described the festering problems at Oroville as a “long-term systemic failure.”
Retrieved November 2, 2018 from https://www.sacbee.com/news/state/california/water-and-drought/article220959620.html