Water & Drought

Just weeks after Oroville Dam crisis, damage found in another key California reservoir

California water officials, still struggling with fixes at Oroville Dam, will have to temporarily shut down the pumping station that delivers water to much of Southern California and Silicon Valley after discovering damage at another key state reservoir.

The state Department of Water Resources confirmed Tuesday that operators discovered damage to the intake structure at the Clifton Court Forebay, a nearly two-mile-wide reservoir that stores water for the State Water Project pumping plant in the Sacramento-San Joaquin Delta near Tracy. Repairs will begin Wednesday. It’s not clear how long they will last.

However, state officials said State Water Project customers won’t lose any water deliveries.

“This is not an emergency of any kind,” said Doug Carlson, a spokesman for the Department of Water Resources. “The water is going to continue to flow to contractors.”

Clifton Court is a crucial piece of the State Water Project’s plumbing. Water stored in the forebay is piped to the nearby pumping station, where it’s delivered to 19 million residents of Southern California, portions of Silicon Valley and about 750,000 acres of farmland in the Central Valley. A third of Southern California’s drinking water typically flows from the Delta pumps.

Ted Page, board president of the Kern County Water Agency, one of the chief agricultural customers of the SWP, said he was told the state will deliver water from the San Luis Reservoir in Merced County while repairs are being made at Clifton Court. Page said he’s been told the shipments from San Luis should be enough to meet customer demands while repairs are underway.

San Luis Reservoir, jointly owned by the SWP and the federal government’s Central Valley Project, is 99 percent full with a little more than 2 million acre-feet in storage. An acre-foot is 326,000 gallons.

“San Luis is full, completely full,” said Page, who farms in Kern County. “And I think the period of time they’re talking about to do the repairs won’t be a big deal.”

The state also could ask the federal government to help pipe water to Southern California through the state-run California Aqueduct by using the U.S. Bureau of Reclamation’s pumping facility. Though it’s only about half as powerful as the state pumping facility and has its own set of contractor demands, the federal pumping station is located near the state’s facilities at the south end of the Delta. The federal system can connect to the California Aqueduct through a connector canal.

The shutdown, while unfortunate, at least comes in winter when demand is relatively low, said Debra Man, assistant general manager of the Metropolitian Water District of Southern California, the massive water wholesaler that supplies nearly half the state’s population.

“This is a perfect time for them to really go in ... and make the necessary repairs,” she said.

The damage at the Clifton Court Forebay likely stems from heavy use of its intake structure, according to a DWR statement to The Sacramento Bee. Near-record rainfall this winter resulted in high river flows in the Delta, which prompted state officials to crank up the pumps to move water south after five-plus years of drought.

“They were pumping at a higher rate than even what the pumps are rated for in my old blue book of the State Water Project,” said Jay Lund, director of the Center for Watershed Sciences at UC Davis.

The problem at Clifton Court comes barely a month after a near catastrophe struck Lake Oroville, the SWP’s primary reservoir.

A giant fracture developed in Oroville Dam’s main spillway, prompting a temporary shutdown of the structure during a heavy storm. Five days later, water flowed over the dam’s emergency spillway for the first time, nearly causing the hillside below to fail. Approximately 188,000 downstream residents were evacuated for two days.

Dam operators averted disaster by ramping up outflows from the damaged main spillway, which lowered lake levels and arrested the flow of water over the faulty emergency spillway. The main spillway has been shut down for two weeks for temporary repairs, but is expected to resume water releases Friday as spring snowmelt increases inflow into the reservoir.

Temporary repairs to Oroville Dam have cost $100 million through the end of February, Nancy Vogel, a spokeswoman for the California Natural Resources Agency, said Tuesday.

It’s not clear yet what it will cost to repair the damage in Clifton Court’s intake structure, which consists of five 20-by-20-foot radial gates that take water from the Old River. Work started on the forebay in 1967 and was completed in 1969.

Oroville Dam was completed in 1968.

“Everybody is facing the fact that the infrastructure is beginning to age,” said Man of Metropolitan.

Gov. Jerry Brown has estimated that California needs to spend tens of billions of dollars shoring up its water infrastructure. He’s asked the Legislature to authorize spending $437 million on short-term flood safety needs.

“This infrastructure system needs improvement,” said Robert Bea, a retired engineer at UC Berkeley. “We’re reactive. We wait until the thing fails.”

Ryan Sabalow: 916-321-1264, @ryansabalow

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