Oroville Dam is the centerpiece and largest water storage facility of the State Water Project. Located about 70 miles north of Sacramento at the Feather River confluence, Oroville Dam creates a reservoir that can hold 3.5 million acre-feet of water.
Features such as a fish barrier dam and pool at Oroville Dam made the SWP one of the first major water projects built with environmental protections as a major consideration.
Besides storing water, the dam also protects downstream residents from the floodprone Feather River—the main feeder of the SWP— and provides major water recreation facilities such as boating, fishing and camping.
One of the country’s foremost experts on catastrophic engineering failures released a new report Thursday on the troubled Oroville Dam that asks a disturbing question: Is the country’s tallest dam leaking?
State water resources officials and federal regulators caused the failure of the Oroville Dam spillway in February by ignoring long-established guidelines and neglecting their duty to manage risks and detect flaws, a scathing report by a Berkeley engineering expert concluded Thursday.
In 2017, it is likely that no other water story grabbed as many headlines in California and across the country as the flood incident at Oroville Dam, the centerpiece of the State Water Project and its largest water storage facility.
On our upcoming Northern California Tour, we will spend time at the Oroville Dam visitor’s center and meet with California Department of Water Resources staff. You’ll see drone footage from February’s flood incident, learn the engineering background on what led to it, and hear about plans to stabilize the spillway before the next winter storms and to finalize repairs by 2018.
Many lake users have complained to the state about fewer recreational opportunities on the lake in the aftermath of the Lake Oroville spillway disaster in February. Since then, the lake level has dropped significantly, meaning boaters have farther to walk after parking their vehicles at the high-water line.
In its eighth memorandum released Thursday, the independent board analyzing the redesign of the Oroville Dam spillways commends the construction contractor’s work and makes slight tweaks to former recommendations.
The state Department of Water Resources has filed a request with the Federal Energy Commission to demolish and reconstruct an additional 240 feet of the main Oroville Dam spillway upper chute this season. The purpose of the change is to ensure the reconstruction can be complete in two seasons, per a recent FERC filing.
Congressman Doug LaMalfa doesn’t want a new license issued for Oroville Dam until some safety questions are answered and some commitments are made to local government. LaMalfa, R-Richvale, sent a letter to Federal Energy Regulatory Commission acting Chairwoman Cheryl LaFleur requesting the delay.
The Department of Water Resources have asked federal regulators to let it demolish and replace an additional 240 feet of the spillway’s 3,000-foot concrete chute before the rains comes this fall, leaving less work for next year.
It’s still too early to know just how significant an impact the February evacuation and Oroville Dam spillway incident had on Yuba and Sutter counties. So far, estimates put damages and losses around $22 million for local municipalities, and that number will continue to grow as county officials lock down estimates.
Nearly 80 days after winning the bid to fix the disastrous Oroville Dam spillways, the contractor Kiewit offered the Chico Enterprise-Record and Oroville Mercury-Register Friday a close-up view of construction efforts.
The preliminaries are just about over. Permanent structural repairs are about to begin at Oroville Dam. Five months after an unprecedented emergency forced a mass evacuation, state officials said Wednesday they’re ready to start replacing the now-demolished lower portions of Oroville’s main flood-control spillway.
Anyone who contemplated the wreckage of the Oroville Dam’s main spillway back in February — either while water was pounding down the shattered concrete structure or when the flow was stopped later and the enormity of the damage was fully visible — probably had this thought cross their mind: “That is going to be tough to fix.”
Facing a crisis after a huge crater formed in the main flood-control spillway at Oroville Dam, officials at the California Department of Water Resources called in an old hand to help: David Gutierrez, a nationally known engineer who had just retired as chief of the agency’s dam-safety division.
Inside a cavernous northern Utah warehouse, hydraulic engineers send water rushing down a replica of a dam built out of wood, concrete and steel – trying to pinpoint what repairs will work best at the tallest dam in the U.S for a spillway torn apart in February during heavy rains that triggered the evacuation of 200,000 people living downstream.
Work at the Oroville Dam will carry on in spite of the 110 degree-plus temperatures anticipated this week. There are protections in place for construction employees with the contractor, Kiewit, and concrete has to undergo a cooling techniques to be able to keep applying it, said Jeff Petersen, the company’s project director in a press conference call Wednesday morning.
The rush of workers and heavy machinery to the shore of Lake Oroville is so vast and unfamiliar it’s fanning rumors across this rural region that the ruckus couldn’t just be for a historic dam repair. … But as state officials gave The Chronicle a tour last week of the construction site, they said the effort was both extensive and relatively straightforward.
Fresh off the Oroville Dam crisis, California lawmakers on Thursday voted to make dam-safety plans secret through language that was quietly inserted into a budget-related bill. The legislation, which requires Gov. Jerry Brown’s signature before becoming law, says emergency action plans at dams would be kept confidential to “protect public safety.”
In February, damage to the spillway of the dam on Lake Oroville in Butte County, California, and erosion under the dam’s emergency spillway threatened to send billions of gallons of water cascading through dozens of California communities. The dam did not collapse, but the damage to the spillway and the emergency spillway was enormous.
Quick thinkers who came up with a plan to rescue millions of salmon using fresh water from fire hydrants during the Oroville Dam emergency were recognized for their efforts Sunday by legislators, the state Department of Fish and Wildlife and other entities.
In the latest skirmish over transparency at the troubled Oroville Dam, a Northern California activist group has sued state officials alleging they’re illegally withholding information about potentially toxic asbestos.
The helicopters alone cost more than $100,000 a day at one point. Weeks of dredging debris ran to more than $22 million. And on the day after the massive evacuation, as the crisis was peaking, the state spent $3,902 on breakfasts and lunches for emergency workers.
Not just concrete and rebar, but “human and organizational” factors that could have contributed to the emergency at the Oroville Dam spillway will be included in the investigation currently underway by an independent team of experts assembled by two national dam associations.
If you’re expecting a quick and easy answer on what caused the spillway failure at Oroville Dam, think again. The leader of the independent forensics team studying the Oroville crisis said Thursday that the crack in the dam’s main flood-control spillway likely was caused by a combination of problems.
The Enterprise-Record/Oroville Mercury-Record got its closest look so far Wednesday at the Oroville Dam spillway work on a site visit hosted by the state Department of Water Resources. … The visit included an hour-long meeting in a conference room at DWR’s Oroville headquarters, and a trip to catch a view of lower spillway blasting around 12:30 p.m. followed by access to the structure above the spillway.
When it comes to repairing the tallest dam in America, sometimes it helps to shrink the problem to a more manageable size. That’s why California water officials are relying on a scale model of the damaged spillway at Oroville Dam to plan their repairs.
State Parks expects a busy Memorial Day weekend at Lake Oroville even with the spillway dominating the news. … A portion of Lake Oroville remains closed as construction continues at the Oroville Dam spillway.
The Department of Water Resources invited downstream levee maintaining agencies and county emergency operators to a meeting in Oroville on Monday to discuss ways of improving operations and planning for future emergency situations.
Federal dam regulators are reevaluating how they conduct dam inspections in the wake of the Oroville Dam spillway crisis, and they’ve ordered the nation’s dam operators to thoroughly inspect their facilities to see “if they have a potential Oroville waiting to happen,” a federal dam inspector said Sunday.
State officials plan to stop releasing water down the mangled main spillway at Oroville Dam on Friday, allowing workers to begin months of round-the-clock repairs to the chute and to an emergency spillway that is also badly damaged.
A hole in the concrete spillway chute of the Oroville Dam first made itself known 100 days ago. How it got there is still a mystery, as is what it will cost to fix the resulting damage and whether a fix will be in place in time for the next rainy season.
One of the wettest years in California history that ended a record five-year drought has rejuvenated the call for new storage to be built above and below ground.
In a state that depends on large surface water reservoirs to help store water before moving it hundreds of miles to where it is used, a wet year after a long drought has some people yearning for a place to sock away some of those flood flows for when they are needed.
America’s tallest dam was built from earth, stone and concrete – and the towering ambition of Gov. Pat Brown. Sixty years before a crisis at Oroville Dam sent thousands fleeing for their lives in February, the late governor brought an almost evangelical zeal to erecting the structure that would hold back the Feather River to deliver water to the parched southern half of the state.
There was going to be a steam train – and a monorail. Plus a major resort featuring a 250-seat restaurant and a 1,000-seat amphitheater. As many as 5 million visitors a year would show up. When it came to wooing Butte County about the construction of Oroville Dam, state officials weren’t shy about setting grand expectations.
Trouble had been developing at the Oroville Dam and the main spillway had been shut down; water started flowing over the emergency spillway and the hillside below it started disintegrating at an alarming rate. Late afternoon on Feb. 12, evacuation orders were issued. By most people’s accounts, it didn’t go well.
If a fresh look had been taken at Oroville Dam — any time between 50 years ago and last year — could the breakup of the spillway have been avoided? Is enough being done to ensure that work done today will keep the communities downstream of the dam safe? Should the Department of Water Resources remain in charge of the dam in the future?
The amount of money Donald Trump’s administration reimburses California for repairs to Oroville Dam could depend on whether the state properly maintained the dam’s spillway prior to it crumbling this winter, a state water official told lawmakers Thursday.
As in most of the other community meetings the Department of Water Resources has conducted about the Oroville Dam spillway crisis, staff members Tuesday night offered profuse apologies and community members voiced distrust. … Many of those who stood to speak said they or their families had also been present for the floods of the past (1955, 1986, 1997).
There’s more debris in the water at the Oroville Dam Diversion Pool than initially thought, and state Department of Water Resources officials now don’t expect to complete dredging and hauling of debris by December. DWR is seeking bids for the remaining work.
The massive failure of the Oroville Dam’s main spillway in February involved two dozen potential design and maintenance problems, including thin concrete, inadequate reinforcing steel and weaknesses in the foundation, a panel of engineering experts reported Wednesday.
In a report released Wednesday, engineers assigned to investigate the February failure of Oroville Dam’s main spillway cited a variety of flaws in the 3,000-foot-long structure, including variations in the thickness of the concrete slabs, poor drainage beneath the spillway, improperly filled cracks and signs of inadequate maintenance.
California is putting communities downstream in danger of flooding with the way it runs the now-crippled Oroville Dam, mayors and county leaders wrote this week in a strongly worded letter to Gov. Jerry Brown.
Pursuing exiting the settlement agreement with the state Department of Water Resources was on the table Tuesday night at a special meeting of the Oroville City Council, but the decision was set aside for later. Most of the council expressed interest in gathering more public opinion on the issue before taking a vote, with a town hall date set for May 22 at 5:30 p.m. in the Municipal Auditorium.
California is borrowing up to $500 million to pay for the crisis at Oroville Dam, although it expects to be reimbursed for its costs. … Kiewit Corp. of Omaha, Neb., has won a $275.4 million contract for the repairs, which are expected to take two years.
California is asking the federal government to pay 75 percent of the hundreds of millions of dollars in repairs to the badly damaged spillways at the nation’s tallest dam, a state water agency spokeswoman said Monday.
The independent board overseeing the repair of the damage main Oroville Dam spillway has recommended the state Department of Water Resources change its priorities and focus on the damaged bottom chute rather than the top.
Outside consultants agree with the state’s plan to spend the next two summers replacing sections of Oroville Dam’s still largely intact upper spillway rather than trying to tear it all out in one season. But the public can’t see the recommendations the independent board of consultants gave the Department of Water Resources to ensure the work is safe and sound.
Cindy Messer apologized Tuesday to several hundred grim Oroville residents who had been ordered to run from their homes three months earlier. They sat rigidly in their seats inside the Oroville Municipal Auditorium at the first public meeting Messer’s agency, the Department of Water Resources, has hosted in Oroville since the February crisis at the dam.
Will there be a viewing platform where the public can watch work being done on the Oroville spillway? That’s the plan, according to Cindy Messer, Chief Deputy Director of the Department of Water Resources.
A power industry consulting firm has proposed a design for the Oroville Dam spillways which involves not repairing the current one, but building a new, wider spillway. … Kenneth Viney, manager of CoastalGen Inc., based in Napa, filed suggestions Monday with the Federal Energy Regulatory Commission, or FERC.
“I’m sorry. I’m sorry for the impact on your lives,” Bill Croyle told a crowd of more than 250 people at the Butte County Fairgrounds. Croyle, the acting director of the Department of Water Resources, answered questions and listened Thursday evening as people stepped up to a microphone and were heard during the first of the water agency’s community meetings about the Oroville Dam spillway disaster and evacuations.
California officials are keeping another document on the Oroville Dam recovery sealed from public view but promise to release a redacted version within a week. The Department of Water Resources filed an update Thursday from the outside consultants advising DWR on Oroville repairs.
Two experts weighed in on the memos that the Board of Consultants assessing the current operations and future spillway options sent to the Department of Water Resources. … A former engineer who reviews disasters and a Chico State University engineering professor reviewed the memos and talked to this newspaper about their questions, comments and concerns.
Members of the state Senate Natural Resources and Water Committee, at an hourlong oversight hearing on the Oroville crisis, questioned Secretary John Laird, the head of the Department of Water Resources and Natural Resources, on the specifications of the $275 million contract awarded earlier this month to Kiewit Corp. of Omaha, Neb., to fix the dam’s two damaged spillways.
For the first time since the Lake Oroville spillway crisis began, members of the state Legislature peppered key water leaders with questions about what happened, what will happen next and what can be learned from it all.
The head of California’s water agency on Tuesday repeated his assertion that an emergency spillway at the Oroville Dam worked, drawing an incredulous response from a state lawmaker who represents tens of thousands of people ordered to evacuate when it was feared erosion at the spillway could lead to catastrophic flooding.
A pair of crippled spillways at Oroville Dam can be repaired in part by November, but a good deal of the work will probably have to be done after the next rainy season, according to reports by an independent panel of experts.
California Natural Resources Agency Secretary John Laird said Tuesday that the February crisis with the broken spillway at Oroville Dam offers an “important opportunity” to assess the safety of the more than 1,400 dams in the state.
“We really want to use the focus on this to look at the issue of dam safety in California,” he said during a hearing of the Senate Natural Resources and Water Committee. “We have the best inspection program of the 50 states but it is clear we can do better.”
The damage has been done and the repair contract awarded. … How much will be the responsibility of homeowners, businesses, farmers and other customers of the more than two dozen local and regional agencies that contract with the State Water Project?
Official reports released Monday say the catastrophic damage to Oroville Dam’s main spillway probably stemmed from swift water flows under the concrete chute, which was cracked and of uneven thickness.
Responding to criticism about secrecy around the Oroville Dam repair effort, California officials released two redacted reports Monday from outside engineers consulting on plans to fix the dam’s battered spillways.
Citing the near disaster at Oroville Dam, a group of congressional Democrats is pushing the government’s watchdog agency to investigate federal oversight of dam safety regulations. … Separately, the California state Senate Natural Resources and Water Committee will hold an oversight hearing on Oroville next Tuesday [April 25].
A disaster expert’s review of the Oroville Dam spillway emergency says the Department of Water Resources could have prevented everything with better design, better construction and better maintenance. Robert Bea prepared the report published Monday.
A coalition of environmental groups that had warned Oroville Dam’s emergency spillway was fatally flawed long before it nearly washed away this winter is demanding that federal regulators open up dam repair plans for public vetting.
Late in the afternoon of Feb. 12, Sheriff Kory Honea was at the emergency operations center for the tallest dam in America when he overheard someone say something that stopped him in his tracks: “This is not good.”
The company that built one of greater Sacramento’s most important flood-control projects in years will fix the damaged spillways at Oroville Dam, site of a near catastrophe two months ago. … Kiewit has considerable experience with dam projects, including the decadelong, $900 million upgrade of Folsom Dam.
As state officials clamp down on records at Oroville Dam, one of the country’s foremost experts on catastrophic engineering failures has used state inspection reports, photographs and historical design specifications to piece together an autopsy detailing why the spillway at the country’s tallest dam failed so spectacularly this winter.
California water officials Monday awarded a $275 million contract to repair the troubled Oroville Dam to a subsidiary of one of the world’s largest construction companies that is headquartered in Omaha, Nebraska.
Design flaws, construction shortcomings and maintenance errors caused the Oroville Dam spillway to break apart in February, according to an independent analysis by Robert Bea for the Center for Catastrophic Risk Analysis at UC Berkeley.
State officials have reopened the damaged spillway at Oroville Dam as another set of rainstorms began moving across Northern California. … Water will continue pouring down the spillway for up to two weeks, depending on how much more rain falls.
Blowing past state officials’ financial projections, three construction contractors submitted bids for the Oroville Dam repairs that begin at $275 million, the Department of Water Resources said Saturday. … DWR said it would spend the weekend reviewing the bids and declare a winner Monday.
California’s top water official said Thursday he’s considering releasing redacted copies of safety and progress reports at the troubled Oroville Dam after his office had tried to keep them secret because of terrorism concerns.
With stormy weather approaching, state water managers announced Thursday they will resume releasing water down a damaged spillway at the nation’s tallest dam. The badly eroded main spillway at California’s Oroville Dam hasn’t been used since March 27.
It’s not just the residents of Oroville, Gridley and Yuba City who are frustrated with the Department of Water Resources’ lack of transparency concerning the Oroville Dam spillways. Two California legislators who represent those living downstream from the dam are also upset that they aren’t getting answers. … The state Senate’s Natural Resources Committee has a hearing scheduled at 9 a.m. April 25 that will go over what happened with the Oroville Dam spillway.
Gov. Jerry Brown’s administration is using federal security regulations written to thwart terrorism to deny public access to records that experts say could guide repairs to the Oroville Dam and provide insight into what led to the near catastrophic failure of its emergency spillway.
California’s Dept. of Water Resources has announced a fast-track plan to replace the shattered spillways at Oroville Dam — at least partially — by November 1, when the rainy season is expected to resume. Meanwhile, engineers at Oroville Dam are drilling cores and conducting geological studies, hoping to better understand February’s near-catastrophic spillway failures.
California officials on Thursday announced an ambitious plan to increase the size of Lake Oroville’s damaged main spillway, allowing it to release nearly twice as much water, as they seek to rebuild the 3,000-foot-long concrete chute that gave way this year.
State officials sketched a two-year recovery plan Thursday for the battered Oroville Dam spillway, revealing a blueprint that’s far from complete, still in need of a price tag and certain to leave the structure partially damaged as the next rainy season approaches.
The Department of Water Resources can operate the Oroville Dam project in an emergency capacity until Aug. 24. The U.S. Army Corps of Engineers approved an emergency permit for the state water agency Feb. 24, and it is good for six months.
Since the Oroville Dam spillway incident highlighted flaws in the current system, Yuba-Sutter officials are in the process of revising evacuation plans. Both Yuba and Sutter counties have been gathering information from the public regarding the February evacuation and plan on using the situation as a learning tool.
Citing potential security risks, state and federal officials are blocking the public’s ability to review documents that could shed light on repair plans and safety issues at crippled Oroville Dam. … The secrecy on the part of state dam operators prompted state Sen. Jim Nielsen to call for an immediate oversight hearing.
President Donald Trump announced Sunday more than a half-billion dollars would be coming to California to help cover the damage from the winter storms, including $274 million for repairs to the Oroville Dam spillway. The fulfillment of the fourth presidential declaration for damage from the winter storms totals an estimated $540 million.
The state Department of Water Resources gave the overseeing federal agency of the Oroville Dam what it asked for last week — a schedule for the independent review team investigating the cause of the spillway failures, but it listed no deadline for a final report from the team.
The operators of Oroville Dam acknowledged Monday they might not be able to permanently repair the dam’s battered main spillway in time for the next rainy season, but said they’re confident the fractured structure will be usable.
California’s top water manager said Monday that the problem-plagued Oroville Reservoir will have a new spillway in place to prevent potentially dangerous outflows of water in time for the next rainy season.
In the wake of a near disaster at Oroville Dam caused by heavy runoff and a damaged spillway, the former chief of flood operations for the U.S. Army Corps of Engineers said last week it may be time to reconsider how the reservoir is operated to avert such dilemmas.
The main spillway at Oroville Dam is riddled with design flaws and so badly damaged that an independent panel of experts hired by the state has concluded it’s probably impossible to repair the structure completely before the next rainy season begins in November.
Safety experts say there is no time for delay in a state plan to restore the 770-foot Oroville Dam, and they warn California would face a “very significant risk” if a damaged spillway is not in working order by fall, the start of the next rainy season.
In their 70s and 80s now, some men who built the Oroville Dam still remember those tough days well, some 50-odd years later. Most of the people they worked with have since passed on, but some of the former construction workers who are living in Oroville have continued to meet up over the years.
In the nearly 50 years since the Oroville Dam was completed, construction methods have changed. Chico State University construction management professor Chris Souder consulted on the Folsom Dam auxiliary spillway project which began construction in 2008 and is on pace to be completed in October.
The state Department of Water Resources Friday said the cost associated with the ongoing crisis at Oroville Dam totaled about $100 million through the end of February. … Meanwhile, dam operators Friday began releasing water down the damaged main spillway for the first time since flows were halted there Feb. 27.
Naturally-occurring asbestos has been found in the rock formations and in the air near the damaged Oroville Dam main spillway, according to a press release. Although California Department of Water Resources said risk to workers and the surrounding community is minimal, dust-control operations are being increased.
The Department of Water Resources is planning to resume flows this week through Oroville Dam’s damaged main spillway, and warns that Feather River flows will increase to 40,000-50,000 cubic feet per second.
Long before a fractured spillway plunged Oroville Dam into the gravest crisis in its 48-year history, officials at a handful of downstream government agencies devised a plan they believed would make the dam safer: Store less water there.
A damaged flood control spillway at the Oroville Dam may have to be used as early as next week as storm runoff and snowmelt continue to fill the massive reservoir on the Feather River, state water officials said.
Just how many people are out working at Oroville Dam in response to the spillway emergency and how much is it going to cost? Both reporters and elected representatives have struggled to get an answer to that question.
When state water officials scaled back their mass dumping of water from the damaged Oroville Dam this week, they knew the riverbed below would dry up enough to allow the removal of vast piles of debris from the fractured main spillway.
There are 1.7 million cubic yards of rubble at the bottom of the Diversion Pool, effectively splitting it into two bodies of water. The plan with the spillway shut off, according to the California Department of Water Resources, is to remove enough of it to clear a channel and get the water that is backed up on one side of the rubble to flow between the two sides.
California Natural Resources Secretary John Laird told the U.S. Senate Environment and Public Works Committee on Wednesday that further deterioration of the nation’s aging flood control and water infrastructure systems will put lives at risk.
Crews worked Tuesday to clean up dirt and debris from the base of Oroville Dam and biologists rush to save stranded fish after state officials shut off the flow of water from a damaged spillway at the Northern California lake.
Geologists attempted for the first time Tuesday to figure out what to do about the vast, yawning canyon dug out of the earth after a crater opened up in the Oroville Dam’s concrete spillway and diverted water at high speed into the adjacent hillside.
When California state biologists crested a sandbar along the Feather River on Tuesday morning, they expected to find at least some of the water that just a day before had raged through the channel, too deep to stand in – and plenty of fish needing to be rescued.
[Oroville] Dam operators gradually scaled back water releases to zero over a six-hour period, providing breathing room for construction crews trying to clear debris from a badly choked Feather River channel and restart the dam’s critically needed hydroelectric plant.
For three weeks, Oroville Dam’s fractured main spillway and the surrounding hillsides have taken a nearly nonstop pounding. The stunning waterfall crashing down what’s left of the 3,000-foot concrete span has split the spillway in two and carved massive canyons on either side.
Oroville Dam operators plan to halt water releases from the dam’s battered spillway Monday in order to ramp up efforts to remove a debris pile that’s preventing them from restarting a hydroelectric plant.
As heavy winter storms continue to hammer California, the Legislature is launching a review of dam and levee safety and bracing for major investments necessary to shore up flood control throughout the state.
Nine days ago, with the Oroville Dam under stress and battered by more harsh weather, Gov. Jerry Brown said he had no immediate plans to visit the site, suggesting “I don’t think they need politicians fluttering around.”
Lake Oroville will partially reopen on Thursday, nearly two weeks after more than 180,000 Northern California residents evacuated their homes and the lake area closed due to fears that the emergency spillway at Oroville Dam could fail.
The Department of Water Resources plans to remove at least some of the debris at the bottom of the Oroville Dam spillway and study the structure, but just aren’t sure when they’ll have a chance to do that.
Not far from the main drag through Oroville, a dozen local business owners and city officials faced each other in a hotel lunchroom Tuesday. They sought to begin developing an advertising campaign to transform a barrage of negative images and news reports about frantic efforts to prevent catastrophic flooding into a lucrative tourist attraction, albeit after the Feather River Basin’s rainy season ends in April.
After the state Department of Water Resources reached its goal early Monday morning of lowering the water level at Lake Oroville by 50 feet, officials said heavy rains would likely cause lake levels to rise several feet.
Twelve years ago, widespread destruction from Hurricane Katrina on the Gulf Coast helped compel federal engineers 2,000 miles away in California to remake a 1950s-era dam by constructing a massive steel-and-concrete gutter that would manage surging waters in times of torrential storms.
The badly damaged main concrete spillway at Oroville Dam was pounded by massive volumes of stormwater this month, but its failures occurred well short of the maximum flow that engineers designed the system to handle.
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.
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.
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.
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 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.
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.
Work crews repairing Oroville Dam’s damaged emergency spillway are dumping 1,200 tons of rock each hour and using shotcrete to stabilize the hillside slope, an official with the Department of Water Resources told the California Water Commission today.
The pace of work is “round the clock,” said Kasey Schimke, assistant director of DWR’s legislative affairs office.
At churches, fairgrounds and other makeshift shelters, thousands of Californians packed what belongings they had into garbage bags and suitcases to return home Tuesday, two days after they were told to flee the threat of massive flooding from a dam’s damaged spillway.
Six months before rushing water ripped a huge hole in a channel that drains a Northern California reservoir, state inspectors said the concrete spillway was sound. As officials puzzle through how to repair Oroville Dam spillway, federal regulators have ordered the state to figure out what went wrong.
With both spillways badly damaged and a new storm approaching, America’s tallest dam on Tuesday became the site of a desperate operation to fortify the massive structures before they face another major test. … In a sign of the progress made Tuesday, officials downgraded the evacuation order to a warning, allowing all evacuated residents to return home.
President Trump issued major disaster declarations to enable federal funding for California on two fronts — to aid with the Oroville Dam spillway damage and mass evacuations and to help the state deal with the widespread effects of January’s storms.
There’s another storm bearing down on troubled Oroville Dam, set to begin late Wednesday. But state officials say they believe the precipitation will be mild enough – and the reservoir empty enough – to handle this latest challenge.
Shock over the emergency evacuation downriver from the Oroville Dam has given way to serious questions about how California is coping with its aging infrastructure — which the American Society of Civil Engineers says would cost the state a staggering $65 billion per year to fix and maintain after years of neglect.
A huge Northern California reservoir, held in place by a massive dam, has always been central to the life of the towns around it. Now the lake that has brought them holiday fireworks and salmon festivals could bring disaster.
Gov. Jerry Brown asked the Trump administration for a federal disaster declaration for the emergency at Oroville Dam on Monday evening, citing the impending arrival of more storms and the potential need to resort again to the dam’s emergency spillway, which has been severely eroded.
As California waited Monday night to see if President Donald Trump would grant Gov. Jerry Brown’s request for emergency funding for 10,000 evacuees who lived in the shadow of the Oroville Dam, FEMA began preparing for the worse.
California Gov. Jerry Brown, appealing to the Trump administration for direct federal assistance on the Oroville Dam’s emergency spillway, said Monday that he remains encouraged that the state and federal government can work constructively.
Water levels dropped Monday at California’s Lake Oroville, stopping water from spilling over a massive dam’s potentially hazardous emergency spillway after authorities ordered the evacuation of nearly 200,000 people from towns lying below the lake. California Department of Water Resources officials are waiting for the light of dawn to inspect an erosion scar on the spillway at the Oroville Dam, the nation’s largest.