Communities just downstream of California’s Lake Oroville dam would not receive adequate warning or time for evacuations if the 770-foot-tall dam itself – rather than its spillways – were to abruptly fail, the state water agency that operates the nation’s tallest dam repeatedly advised federal regulators a half-decade ago.
Dam experts around the country are focusing on a leading suspect: Tiny bubbles. The prospect is simple, yet terrifying and has been the culprit in a number of near disasters at dams across the globe since engineers discovered about 50 years ago.
Water releases through the damaged main spillway at Oroville Dam were scaled back Thursday to allow crews to reach and remove a pile of debris that has built up at the bottom of that chute, officials said.
Feeling confident they’ve created sufficient empty space in Lake Oroville for the time being, state Department of Water Resources officials said they reduced spillway outflows so they could address another looming challenge: restarting the dam’s hydroelectric plant, which can release additional water when operational.
Just over a week ago, a series of events began to unfold rapidly at Oroville Dam. … I [General Manager Jeffrey Kightlinger] had the opportunity to fly over Oroville this past week and I was inspired by the hard work and cooperative effort of all involved. The flood control spillway is in operation lowering the lake level to make room for more storm flows.
Jeffrey Mount, a leading expert on California water policy, remembers the last time a crisis at the Oroville Dam seemed likely to prompt reform. It was 1997 and the lake risked overflowing, while levees further downstream failed and several people died.
Rainwater erosion alongside the Oroville Dam’s main spillway appears to have contributed to the heavy damage that prompted a crisis, forcing more than 100,000 to be evacuated from their homes, a report reviewed by The Times showed.
The frantic effort over the last few days to lower water levels at Oroville Dam after the structure’s two spillways became damaged is part of a larger drama playing out as California rapidly shifts from extreme drought to intense deluges.
Heavy winter rains and erosion of the Oroville Dam’s two spillways sparked an evacuation of at least 188,000 people living in the communities of Oroville, Marysville, and surrounding downstream areas. The events that unfolded over the past eight days can inform a more educated conversation about water management going forward.
Days before nearly 200,000 people downstream of Lake Oroville were ordered to evacuate because of problems with two spillways at the dam, there were millions of other evacuees – residents of the Feather River Fish Hatchery. … Why all the trouble for some fish? Spring-run Chinook salmon and steelhead are both listed as threatened under the Endangered Species Act.
The near-failure on Sunday evening of the auxiliary spillway at Oroville Dam and the ongoing emergency operations to contain flood waters in California’s second-largest reservoir and shore up its eroding outlet are a tale of caution for the nation’s aging dam fleet. … Dam safety experts cite money as the most significant impediment to safer dams.
Officials raced to drain more water from a lake behind battered Oroville Dam as new storms began rolling into Northern California on Wednesday and tested the quick repairs made to damaged spillways that raised flood fears.
The Oroville Dam debacle is a wake-up call to California. If we heed the call, we may be able to avoid what could certainly be other disasters and wrong turns in the state water system as we head into an age typified by extreme weather events associated with climate change.
The critical document that determines how much space should be left in Lake Oroville for flood control during the rainy season hasn’t been updated since 1970, and it uses climatological data and runoff projections so old they don’t account for two of the biggest floods ever to strike the region. … Most recently, the issue of outdated dam manuals came up in the context of California’s five-year drought.
Northern California residents, who had spent days at evacuation shelters, were allowed to return to their homes but many stayed only long enough to pack valuables before fleeing an approaching storm that will test recently repaired spillways at the nation’s tallest dam.
When operators of Oroville Dam suddenly ordered evacuations on Sunday, it focused a big spotlight on a crucial piece of California’s flood-control infrastructure – spillways. … Some of these dams are getting upgrades, albeit slowly.