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Two years and $1.1 billion later, water flows down Oroville Dam spillway

It worked.

Oroville Dam’s main flood-control spillway reopened for business Tuesday morning, releasing a gentle sheet of water into the Feather River for the first time since the 2017 crisis that sent 188,000 people fleeing for their lives.

As a media throng and a passing parade of motorists watched from across the river, a siren sounded and water began cascading down the rebuilt spillway shortly before 11 a.m. The water flowed evenly, without drama, before hitting the concrete “teeth” at the bottom of the concrete chute and turning into foam as it spilled into the river.

It was a far cry from the scene two years ago, when the massive sinkhole in the spillway turned water releases into an angry, boiling mess that sparked the evacuation and ultimately destroyed the lower half of the structure and much of an adjoining hillside.

The initial water release was a mild one: about 3,300 cubic feet per second, or a fraction of what the reservoir was releasing when the main spillway fractured in 2017. The releases were scheduled to ramp up to 8,300 cfs in the afternoon, and increase in volume in the coming days and weeks.

DWR officials tried to portray the reopening of the spillway as business as usual: Water levels have been rising at Lake Oroville, the spring snowmelt season is beginning and it was simply time to draw down the reservoir for flood control. “This is normal operations,” said Molly White, chief of water operations at DWR.

Officials also insisted they weren’t nervous about using the spillway, saying the immense structure had been rebuilt to state-of-the-art standards, using technology that didn’t exist during original construction.

“We’re prepared; we’ve spent the last two years restoring full functionality,” said Joel Ledesma, the agency’s deputy director. “The industry has learned a lot since this (dam) was built 50 years ago.”

Visual reminders of the crisis abounded. Excavators and bulldozers continued working, as the water flowed, on patches of hillside that eroded two years ago. Ledesma said crews are performing “minor finishing work” on the concrete spillway that won’t compromise operations or safety.

While there was no way to test the spillway before Tuesday, project manager Jeff Petersen of Kiewit Corp., the main contractor on the reconstruction, said components were thoroughly tested as reconstruction took place. “The concrete was tested; the drain system’s been tested,” he said.

For some Oroville residents, Tuesday brought back frightening memories of the 2017 emergency.

Watching a live feed of Tuesday’s release on her phone from downtown, Katelyn Stafford recalled being pregnant with her youngest son when Oroville residents received the order to head to high ground. Her family was stuck in traffic for three hours on the way to Chico, 20 miles away.

She remembered calling her mother to tell her the family could die if a giant sheet of water poured out of the dam.

“I told her, ‘We’re going to be underwater, swimming,’” said Stafford, owner of Off the Top Barber Shop.

Nearby, Debbie Peck and Jill Farris were opening the doors of the Brush Strokes Art Studio and Gallery in downtown Oroville as the spillway gates were about to open.

They said they’re weren’t worried, but they’re hoping the successful use of the rebuilt spillway is a milestone that allows Oroville to move on after a rough couple of years. The former Gold Rush community sits in the valley below Paradise, which was destroyed last fall in the Camp Fire. As the fire burned, residents worried their city could be next. Oroville has since had to accommodate an influx of fire evacuees.

“We’re looking forward to moving in a positive direction,” Peck said.

The spillway crisis reopened a longstanding feeling of distrust between residents and DWR officials about the operations at Orovillle, the nation’s tallest dam. Even as it became apparent that the initial reuse of the spillway was successful, some residents had lingering concerns.

Don Bartlett, an area resident who stopped to watch from the overlook, said the re-launch of the spillway could help restore trust between DWR and locals. “They’re trying to win it back,” he said.

Local elected officials still haven’t been won over.

Butte County Supervisor Bill Connelly released a letter Tuesday to the Federal Energy Regulatory Commission, which regulates the dam, questioning DWR’s commitment to safety.

The crisis began Feb. 7, 2017, when a crater opened roughly halfway down the 3,000-foot-long concrete chute as water was being released during a heavy storm. Dam operators reduced water releases to limit the damage, which allowed the water in Lake Oroville to rise to unprecedented levels. On Feb. 11, water poured over the nearby emergency spillway, which rests atop a natural hillside, for the first time since the dam opened in 1968.

Barely a day later, the hillside began eroding, prompting fears that the emergency spillway would crumble and billions of gallons of water would cascade into the Feather River and swamp downstream communities. Officials ordered 188,000 residents to evacuate as dam operators frantically ramped up water releases from the main spillway.

The strategy worked: Lake levels dropped and water stopped flowing over the emergency spillway. In the weeks that followed, DWR officials continued to pour water down the battered main spillway. By the time the spillway was shut off for good May 19, 2017, much of the lower half of the structure was gone and an enormous ravine had been carved into the adjacent hillside.

Since then, DWR’s main contractor Kiewit has replaced the entire main spillway and lined a portion of the hillside beneath the emergency spillway with concrete. Kiewit has poured more than 1.2 million cubic yards of concrete — enough to fill 372 Olympic-sized swimming pools — and installed a state-of-the-art drainage system designed to prevent a repeat of the 2017 debacle. The work on the emergency spillway won’t be completed until later this year, although Ledesma said it could function safely this winter if needed.

The water level behind the dam sat at 854 feet, about 50 feet below the level at which water would flow over the emergency spillway. The reservoir is about 80 percent full.

The entire crisis has cost $1.1 billion, including $630 million for the spillway repairs, $310 million for dredging concrete chunks and other debris from the river; and $160 million for responding to the immediate emergency in early 2017.

An exhaustive 2018 report by a panel of independent engineers said the crack in the spillway was the result of “long-term systemic failure” dating to the design and construction. Citing the panel’s conclusions, FEMA last month refused to reimburse California for $306 million worth of repairs to the upper end of the main spillway, saying its weaknesses were caused by “pre-existing conditions.” California officials are appealing FEMA’s decision. Any costs that California must absorb will be passed on to the regional water districts that store water behind the dam.

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