Unlike the main concrete-lined spillway, the emergency spillway is essentially a hillside.
|
|
As the spillway continued to crumble, an emergency spillway was being considered, the department said on Twitter.
|
|
The reconstruction work was necessary to safely operate the main spillway and ensure functionality of the emergency spillway.
|
|
The water had eroded part of the spillway and some of the land between the spillway and the dam.
|
|
The emergency spillway was always considered a backstop option if the existing 3,000-foot-long spillway could not be utilized for outflows.
|
|
Engineers were able to use the damaged spillway to a limited extent although water releases into damaged spillway caused further erosion of the channel.
|
|
State engineers were able to resume significant outflows from the primary concrete spillway on Sunday as a way to ease pressure on the emergency spillway.
|
|
The flow of water on the emergency spillway eventually stopped Sunday night as the Department of Water Resources withdrew more water from the other spillway.
|
|
With the main spillway damaged, the lake quickly filled to capacity and water began flowing over a concrete weir that serves as an emergency spillway.
|
|
The main spillway is prepared to reopen, water resources officials said, and work on the emergency spillway is expected to be finished later this year.
|
|
Flows over the emergency spillway had stopped, while about 100,000 cubic feet-per-second of water continued down the main spillway, the Department of Water Resources said.
|
|
"We're trying to determine if the spillway is not usable do we need to use an emergency spillway," Maggie Macias, a spokesperson for the DWR, said Thursday.
|
|
Oroville Dam, California's second-largest reservoir, was crippled last week when its primary emergency spillway suffered significant erosion and later the emergency spillway too experienced critical damage.
|
|
They worried that heavy rain and fast-rising waters could overwhelm the main concrete spillway of the Oroville Dam, overflow the emergency spillway and flood communities downstream.
|
|
The state has been repairing the damaged emergency spillway at the Northern California reservoir and also has to address the erosion problem on the dam's primary spillway.
|
|
The main spillway is releasing water at 100,000 cubic feet per second in an effort to reduce the amount of water traveling down the emergency spillway, authorities said.
|
|
"We urged them to put concrete on the spillway -- our argument was that without a proper spillway, the hillside would wash away and cause catastrophic flooding," Stork said.
|
|
Built in the 1960s, the spillway lacked modern enhancements and hadn't been properly fortified, according to a report by a panel of independent investigators released after the spillway collapsed.
|
|
Authorities ordered people to leave the area on Sunday when a hole developed in an eroded area of the spillway, raising concerns that the spillway could fail and flood communities downstream.
|
|
The strength of a secondary emergency spillway could be an issue, Stork said, as well as potentially broken and cracked "anchor tendons" that are integral for raising and lowering the spillway gates.
|
|
Of the two, the emergency spillway is a last resort.
|
|
The state began preparations Thursday to use the emergency spillway.
|
|
The spillway should be repaired within 24 hours, he said.
|
|
An aerial view of the damaged spillway, February 27, 0003.
|
|
Though damaged, the primary spillway was still useable, officials said.
|
|
It was also 43 inches (45 centimeters) below a spillway.
|
|
It is just a really big drain called a spillway.
|
|
Damage to the main spillway triggered a series of problems culminating with the first use of the emergency spillway, which quickly began eroding and threatened to unleash a torrent of water on cities downstream.
|
|
This week, the emergency spillway was used for the first time since the dam's construction in the 1960s when its main spillway began to erode, sending chunks of concrete flying down the damaged outlet.
|
|
The damage to Oroville Dam, where the primary spillway developed a giant gash and the emergency spillway threatened to erode, illustrates the hazard of relying on aging infrastructure to protect us from extreme weather.
|
|
The state said Saturday that repairs to the primary spillway at Oroville Dam — the nation's tallest earthen dam — could run as much as $200 million but that was before critical damage to the emergency spillway.
|
|
Officials warned residents that the spillway could fail within an hour.
|
|
When the river level gets dangerously high, the spillway is opened.
|
|
Now I can check this spillway off my to-do list.
|
|
The concrete primary spillway remains splintered as crews have begun repairs.
|
|
The spillway repair is an estimated $500 million, local media reported.
|
|
A breach of the Swar irrigation dam's spillway at 4 a.m.
|
|
Authorities feared that the spillway would fail and send water downstream.
|
|
Further, the sheriff said the massive hole in front of the spillway was thoroughly inspected by federal and state experts and it revealed there was no erosion that compromised the overall integrity of the backup spillway.
|
|
Also, he maintained that the concrete-lined spillway (even with its own erosion issues) still is able to provide significant outflows and lower lake levels while also reducing the chance of needing to use the emergency spillway.
|
|
The emergency spillway developed a hole Sunday, raising the risk of collapse.
|
|
We can probably expect more, and worse catastrophes than Oroville's crumbling spillway.
|
|
The destruction of the unpaved emergency spillway was less of a surprise.
|
|
Overflowing water surging out of California's damaged Oroville Dam spillway in 28.
|
|
It's kind of a big deal when they open up this spillway.
|
|
Water was rushing over the spillway of the Guajataca Dam on Saturday.
|
|
Areas downstream would flood if water goes over the spillway, Lau said.
|
|
A day later, however, engineers noticed a crevice opening in the spillway.
|
|
Workers are trying to repair a hole in the dam's main spillway.
|
|
The sheriff credited swift action by the Department of Water Resources to shore up the emergency spillway and use the main spillway to relieve pressure on the dam, averting the immediate danger of a dam failure, Honea said.
|
|
On Sunday afternoon, the Department of Water Resources warned that the lip of the auxiliary spillway, which was never built to be as sturdy as the main spillway, was in danger of "failure" if the ground beneath gave way.
|
|
Unfortunately, spillway failures are a particular hazard facing a large number of dams.
|
|
" He added that the spillway is stable and they are making "great progress.
|
|
Alarm bells went off after authorities found a hole in the dam's spillway.
|
|
The company will rebuild the main spillway, place a 65-foot underground wall to stop erosion on the emergency spillway and lay concrete at least 10 feet thick between the cutoff wall the concrete weir that holds water in the lake.
|
|
The energy regulatory commission rejected their motion to reinforce the emergency spillway with concrete.
|
|
Flows through the spillway peaked at 12,600 cubic feet per second at 1 a.m.
|
|
The question is how much impact that might have on Oroville Dam's damaged spillway.
|
|
On Tuesday, officials began noticing large chunks of concrete missing from the dam's spillway.
|
|
"The collapse is caused by the damaged spillway," the paper quoted him as saying.
|
|
Crews opened a small sluice on the spillway Saturday to begin dewatering the reservoir.
|
|
Officials said crews would work to plug the crevice in the spillway with rocks.
|
|
As millions of gallons of water washed over the emergency spillway, it eroded further.
|
|
EMERGENCY EVACUATION: Auxiliary spillway at Oroville Dam predicted to fail within the next hour.
|
|
"The next week of storms could potentially bring hundreds of billions of gallons of water into Lake Oroville, adding pressure back onto the already compromised structure of the concrete spillway and emergency spillway next to Oroville Dam," CNN Senior Meteorologist Dave Hennen said.
|
|
The emergency spillway, which is an embankment covered with trees, is a last resort and was used for the first time in history on Saturday when the lake topped 225 feet, its capacity, and a light flow of water washed into the spillway.
|
|
The dam's primary spillway developed a 200-foot-long, 20-foot-deep hole last week.
|
|
A spillway is a structure that allows a controlled release of water from a dam.
|
|
The evacuation was ordered Sunday afternoon after engineers spotted erosion on the dam's secondary spillway.
|
|
The dam's emergency spillway also suffered significant erosion problems after the reservoir exceeded capacity Feb.
|
|
In Oroville, local groups raised concerns 12 years ago, citing the potential for spillway failure.
|
|
Bottom: Location of water wells active in 2012, local industry and the Bonnet Carre Spillway.
|
|
The spillway had to be opened on February 27 and wasn't closed until April 11.
|
|
But he stressed "the integrity of the dam is not impacted" by the damaged spillway.
|
|
"I think there will be more spillway openings, though hopefully not every year," he said.
|
|
"There's a pretty significant chance we won't even use the spillway this year," she said.
|
|
Here's a diagram: The problem is that Oroville Dam's main spillway has become severely damaged.
|
|
Then, early Saturday, as the water continued to rise, the emergency spillway came into play.
|
|
With a deluge of water, the dam's channel for overflowing water, called a spillway, crumbled.
|
|
Jerry Brown too defended the state's handling of the dam spillway crisis and welcomed more scrutiny.
|
|
"Any spillway -- primary or emergency -- usually has some kind of protection, a concrete basin," said Tullis.
|
|
CNN's Paul Vercammen spent Sunday night reporting on how workers planned to reinforce the emergency spillway.
|
|
That was the first time the emergency spillway was used in the dam's 48-year history.
|
|
As a safety precaution, the motion urged FERC to have the emergency spillway paved with concrete.
|
|
As far as the failure of the main spillway was concerned, cavitation was clearly the culprit.
|
|
Since the dam was dedicated in 1969, the main spillway has only been used before Jan.
|
|
Environmental groups had warned for more than a decade that the dam's spillway was not safe.
|
|
Water has since stopped flowing over the auxiliary spillway, allowing crews to assess the damage there.
|
|
While Department of Water Resources (DWR) officials called conditions at the dam's emergency spillway "stable" earlier in the day, authorities warned residents of Oroville, Marysville, Hallwood, Olivehurst, Plumas Lake, and Wheatland to evacuate immediately this evening:A hazardous situation is developing with the Oroville Dam auxiliary spillway.
|
|
As of Wednesday, the crater in the spillway was estimated to be a 200-foot-long strip.
|
|
By Saturday, the reservoir reached its elevation capacity of 901 feet, which automatically triggered the emergency spillway.
|
|
With the significant damage to the emergency spillway, the price tag on repairs could go much higher.
|
|
They also planned to use grout in damaged areas of the emergency spillway to prevent further erosion.
|
|
On Saturday, Oroville Dam reached its elevation capacity of 901 feet, which automatically triggers the emergency spillway.
|
|
The main spillway is damaged from significant concrete erosion but has still been releasing water this week.
|
|
Frantic efforts continue to shore up the emergency spillway before a major storm reaches the Oroville area.
|
|
Last week, the primary spillway was damaged by erosion, according to the California Department of Water Resources.
|
|
At Oroville Dam, the emergency spillway is only used if water levels reach 901 feet in elevation.
|
|
Saturday marked the first time the emergency spillway has been used in the dam's 27-year history.
|
|
They were using helicopters, heavy machinery and dumping rocks into the crevice of the damaged emergency spillway.
|
|
Cracks began to appear around the spillway last week, according to the declaration of emergency from Gov.
|
|
Last week, the Oroville Dam's crumbling emergency spillway triggered the emergency evacuation of more than 248,2199 people.
|
|
The erosion caused by the rushing waters created a sizeable hole in the midsection of the spillway.
|
|
Last year, a family of six drove their pleasure boat down the spillway and four people died.
|
|
When the river was at flood stage, the spillway gates would open, relieving pressure on the levees.
|
|
On Tuesday, a gaping hole opened in the main spillway that is used to release extra water.
|
|
Canada's Aecon is part of a joint venture also bidding on a generating station and spillway contract.
|
|
The closed gates at the mouth of the spillway, the final safety valve at the Mosul Dam.
|
|
Here's what else we know: • By Sunday night, water was no longer flowing over the emergency spillway.
|
|
Trucks full of boulders have also been dumping their cargo on the damaged portions of the spillway.
|
|
Water was diverted to an earthen emergency spillway, but major erosion was detected there over the weekend.
|
|
Workers have been moving 1,200 tons of rock and slurry an hour into the dam's emergency spillway.
|
|
Cracks began to appear around the spillway last week, according to the declaration of emergency from Gov.
|
|
The emergency spillway appears more like a muddy mess of small creeks that spill menacingly from the reservoir.
|
|
There have been concerns about Oroville Dam safety since the erosion of the primary spillway was discovered Tuesday.
|
|
Millions of gallons began washing over this emergency spillway, essentially an embankment covered with brush, trees and rock.
|
|
Crews were breaking and bagging rocks to drop into the hole eroded in the auxiliary spillway, officials said.
|
|
Oroville Dam, the state's second-largest reservoir, suffered damage to its primary concrete-lined spillway due to erosion.
|
|
The dam&aposs spillway can control the flow of surplus water up to 890 feet above sea level.
|
|
Fears of a catastrophic failure to the emergency spillway, which was activated for the first time on Feb.
|
|
Why weren't more efforts made to prevent spillway erosion after concerns were raised more than 10 years ago?
|
|
Water is no longer flowing over the emergency spillway and lake levels are continuing to fall, Honea said.
|
|
The emergency spillway that's eroding had never been used before in 48 years of existence, the DWR said.
|
|
Dump trucks were used to carry boulders to the dam's damaged backup spillway and helicopters also dropped rocks.
|
|
The animation shows water gushing down the primary spillway, which eventually experienced a failure at its lower levels.
|
|
Failure of the auxiliary spillway structure will result in an uncontrolled release of flood waters from Lake Oroville.
|
|
A small flow of water now trickles down the damaged spillway at the Oroville dam as inspectors investigate.
|
|
Kaung Myat Thein said the dam was regularly inspected and a spillway collapse could not have been predicted.
|
|
The greater danger was posed by the emergency spillway, which was subject to urgent repairs in recent days.
|
|
The move came one year after spillway failures at Oroville Dam prompted evacuation orders for thousands of people.
|
|
Water also topped over the dam's emergency spillway for the first time in its nearly 50-year history.
|
|
Correction: This story has been updated to reflect that the spillway reopened Tuesday after failing two years ago.
|
|
Saturday was the first time the emergency spillway came into use since the dam was completed in 1968.
|
|
Last week, crews observed a hole in the dam's concrete spillway, which drains water into the Feather River.
|
|
A water utility worker looks towards the spillway at the Oroville Dam in Oroville, California, on February 212, 22017.
|
|
A water utility worker looks towards the spillway at the Oroville Dam in Oroville, California, on February 13, 1003.
|
|
In aerial footage, water is seen roaring down the dam's damaged spillway, looking like the world's most terrifying waterslide.
|
|
The emergency spillway is an unlined channel that is essentially a natural hillside with rocks, brush and other debris.
|
|
DWR said Saturday the cost to repair the primary spillway was estimated to be as much as $200 million.
|
|
Lake Oroville had water levels so high the spillway was used Saturday for the first time in 50 years.
|
|
With the significant damage to the emergency spillway, the price tag on repairs is likely to go much higher.
|
|
Normally the dam would use its concrete-lined spillway to discharge water, but that primary channel is severely damaged.
|
|
" Even so, the state agency cautioned that "the rate of flow into the ungated emergency spillway may change quickly.
|
|
Authorities ordered mandatory evacuations over concerns that an emergency spillway at the dam could fail and threaten nearby communities.
|
|
Work continued Friday to place rock, aggregate and cement slurry into areas of the emergency spillway affected by erosion.
|
|
The water level eventually fell without breaching the dam, and engineers shut down the spillway to investigate the damage.
|
|
In June, an analysis led by UCLA researchers concluded the Oroville Dam spillway overflow was worsened by climate change.
|
|
That could well involve replacing the damaged main spillway completely and paving the hillside course of the emergency one.
|
|
Operation of the auxiliary spillway has lead to severe erosion that could lead to a failure of the structure.
|
|
The water resources department said crews using helicopters would drop rocks to fill a huge gouge in the spillway.
|
|
Now dry, this spillway was once covered in water, and not lava or debris as some scientists had speculated.
|
|
The main spillway, a separate channel, is also damaged because part of its concrete lining fell apart last week.
|
|
This heat also brought with it the summertime bugs that swarm near the spillway and any other moist area.
|
|
A hole in the spillway of the nation's tallest dam prompted evacuation orders for Oroville and several other communities.
|
|
"The dam has never experienced spillway flow or a flood event that has loaded the dam significantly," Barta said.
|
|
This prompted fears that the spillway could collapse, sending a 30-foot wall of water into the valley below.
|
|
The emergency spillway is also currently under construction, with construction crews placing a concrete cap on a concrete buttress.
|
|
There have been concerns about Oroville Dam safety since the erosion of the primary spillway was discovered a week ago.
|
|
Also, in January 2016 engineers were forced to stabilize a leak considered in a temporary dam spillway site at Folsom.
|
|
But the emergency spillway, which guards against the overflow of the dam when water levels are high, was eroding Sunday.
|
|
Watching the damage After issuing the evacuation orders, authorities noted significant decreases in the water coming over the emergency spillway.
|
|
Workers scrambled late Monday to make repairs at the battered emergency spillway — essentially a natural hillside — to prevent further erosion.
|
|
Despite plugging the gouged hole in the emergency spillway with rocks, Croyle said challenges remain for California's second-largest dam.
|
|
The flooding also worsened after local authorities decided to open the spillway to release pressure on a dam in Louisiana.
|
|
Image: GettySome 188,000 people from Oroville had to be evacuated in mid-February after the spillway showed signs of failure.
|
|
Here's what lies in ruins: portions of Pacific Coast Highway buried under landslides, a disintegrated spillway and a cracked bridge.
|
|
Authorities believed the emergency spillway, which is earthen, was on the verge of collapse and issued swift, stern evacuation orders.
|
|
About 1,200 feet of the 3,000-foot spillway will be fully reconstructed this year with the rest rebuilt next year.
|
|
The state has also revised plans to shore up the emergency spillway, doubling the amount of concrete it will require.
|
|
Unlike a levee or a spillway, built to stop the river from flooding, it was put up to stop time.
|
|
"(Saturday) Crews will open a small sluice on the spillway in order to begin dewatering the reservoir," a statement said.
|
|
Aerial footage from WeatherNation, a broadcast and digital network, showed a large volume of water flowing over the dam's spillway.
|
|
The flow increased gradually through the night as the spillway was opened in stages, reaching its maximum on Sunday morning.
|
|
But a decision to increase the flow of water through the primary spillway appears to have prevented an imminent failure.
|
|
Reservoir expected to rise During the rains in February 2017, erosion caused a hole to appear in the concrete spillway.
|
|
The upper and lower sections of the spillway were covered with structural concrete and cutoff walls installed on the sides.
|
|
The situation grew less dire later on Sunday as water levels dropped, leaving the weakened unpaved emergency spillway largely intact.
|
|
The reservoir level was well below maximum, operators having drawn it down using another spillway that is also extensively damaged.
|
|
That is when authorities ordered evacuations, concerned that the spillway could fail and send water downstream and toward residential areas.
|
|
There have been concerns about Oroville Dam safety since the erosion was discovered Tuesday at the primary spillway at Oroville Dam.
|
|
The report Sunday said three environmental groups warned the Federal Energy Regulatory Commission about the vulnerability of the hillside emergency spillway.
|
|
They stressed in the motion that the auxiliary spillway was designed to work with a replacement dam that was never built.
|
|
A DWR spokesman said later there's also a possibility they may decide to build an entirely new spillway at the dam.
|
|
Officials say Oroville Lake levels had decreased by Sunday night as they let water flow from its heavily damaged main spillway.
|
|
New images show what's left of the 3,000-foot long concrete spillway—and the tremendous challenge that now confronts repair crews.
|
|
A damaged spillway with eroded hillside is seen in an aerial photo taken over the Oroville Dam in northern California, Feb.
|
|
On the spillway levee's left side, Mississippi water sat flat and still upon the batture, where it shouldn't have been sitting.
|
|
The main spillway is as wide as a 12-lane highway with sidewalls ranging from 22 feet to 30 feet tall.
|
|
The Mississippi was rising rapidly, and there was concern that the gates on a spillway upriver from New Orleans weren't functioning.
|
|
To spare New Orleans, the Army Corps of Engineers opened the Bonnet Carré Spillway, about thirty miles upriver from the city.
|
|
Map by LaTigre During the mock flood, some of the dark pellets had been flushed down the spillway, into Lake Pontchartrain.
|
|
Still, officials were concerned about the integrity of the emergency spillway, and more than 180,000 people were ordered to evacuate. Gov.
|
|
Pacific time, the Department of Water Resources warned in a Facebook post that the emergency spillway would fail within the hour.
|
|
In addition to the flooding over the spillway, both reservoirs have been spreading into nearby subdivisions as the water has risen.
|
|
Officials warned that a 30-foot "wall of water" could be sent rushing downstream if the eroding spillway were to collapse.
|
|
The emergency spillway, like many others, is made largely of earth, with only a concrete weir, or sill, at the top.
|
|
The main spillway had suffered unexpected erosion earlier this week after heavy rains caused a 2770-foot-deep hole in the structure.
|
|
The spillway damage follows a series of storms to hit Northern California, producing rain and snow in the Sierra Nevada mountain range.
|
|
Normally the dam would use its primary spillway but that too was found to have significant concrete erosion earlier in the week.
|
|
The cost to repair the primary spillway was estimated to be as much as $200 million, state officials said over the weekend.
|
|
As officials puzzle through how to repair Oroville Dam spillway, federal regulators have ordered the state to figure out what went wrong.
|
|
One resident of the region said he saw crews in the spillway at least once a year for the past several years.
|
|
One of the state inspectors who went to Oroville Dam in August said authorities may never know exactly what destabilized the spillway.
|
|
So far, there have been no repairs made on the emergency spillway, because teams have been unable to reach the damaged area.
|
|
Erosion left a hole almost the size of a football field and at least 40 feet deep in the main concrete spillway.
|
|
The solution now is to fix the broken main spillway in the summer, said Professor Tullis and Stork of the environmental group.
|
|
The erosion to the Oroville Dam spillway was originally estimated to be a 200-foot-long strip, and about 30-foot depth.
|
|
The Mississippi is expected to reach 60 feet at the spillway on June 9, instead of an earlier forecast of June 5.
|
|
The water level is at 854 feet, 47 feet below the mark where a emergency spillway, which is under repair, is needed.
|
|
Heavy rains last week caused the lake level to rise until the water began to pour down the emergency spillway on Sunday.
|
|
Authorities ordered people to leave the area when a hole developed in an eroded area of the spillway, affecting about 188,000 residents.
|
|
Officials worried the spillway would fail, and one warned a "30-foot wall of water" could flood the communities below the dam.
|
|
The Don Pedro Reservoir in Stanislaus County reached 830 feet elevation Monday, activating its spillway for the first time in 20 years.
|
|
To help disperse the water build-up in the area, officials opened the Oroville Dam's emergency spillway for the first time Sunday.
|
|
California dam At least 188,000 people have evacuated from several Northern California counties after damage to a spillway at the Oroville Dam.
|
|
Officials announced Monday they will open the Morganza Spillway in Louisiana for only the third time since it was built in 1954.
|
|
For comparison, the Bonnet Carré spillway was open from March 8 to March 30 in 2018, and not at all in 2017.
|
|
The bureau was directed by federal legislation to use weather forecasting in its operation of the new spillway to maximize flood safety.
|
|
Crews shut down the spillway to inspect just as a major storm dumped a torrent of rain in the Feather River basin.
|
|
If the water kept rising and the spillway failed to open, the city and the parishes downriver from it would be inundated.
|
|
The early estimates to repair the damaged spillway for the tallest dam in the United States are as high as $200 million.
|
|
Because heavy rain is expected this month, the agency ordered the main spillway be used if the reservoir elevation reaches 830 feet.
|
|
Relentless runoff from the mountains had caused Lake Oroville to flow over its emergency spillway for the first time ever on Saturday.
|
|
The fears center on the auxiliary spillway, which channels water away from the Oroville Reservoir and thereby relieves pressure on the dam.
|
|
More than 210,210 people were evacuated after the authorities warned of the possible failure of an emergency spillway at the Oroville Dam.
|
|
At Lake Oroville, a major man-made reservoir, water began flowing over a never-before-used emergency spillway at the Oroville Dam.
|
|
The aftermath While DWR says the main spillway was reconstructed by November 2018, the agency said finishing work is still in progress.
|
|
The board also recommended engineering changes that enhanced the Hoover Dam's safety, including increasing the capacity of its spillway and flood storage.
|
|
State officials have denied allegations there was lax safety at the Oroville Dam despite a report of previous warnings about the emergency spillway.
|
|
At a news conference Monday afternoon, he said that no water was overflowing the emergency spillway and lake levels were continuing to fall.
|
|
Earlier this week, authorities ordered mandatory evacuations over concerns that an emergency spillway at the Oroville Dam could fail and threaten nearby communities.
|
|
In the main spillway, erosion has opened a hole almost the size of a football field and it's at least 210 feet deep.
|
|
Crews used helicopters to drop bags of rocks into the gouged portion of the emergency spillway, in an effort to plug the hole.
|
|
No repairs yet, since crews can't event get to the spillway, and more rain is expected in the area later this week. 5.
|
|
An emergency spillway for the dam suffered erosion that led to the hasty evacuation of nearly 200,000 from areas downstream on Feb. 12.
|
|
While the opening of Banja's spillway is sans-soundtrack, I'd suggest something on the relaxed, instrumental side, like Nujabes, Whitewoods, or Clams Casino.
|
|
As a result, officials are having to release copious amounts of fresh water into the ocean from the Bonnet Carré spillway in Louisiana.
|
|
The wet winter peaked with the failure of a spillway at the Oroville Dam in 2017, which forced about 250,000 people to evacuate.
|
|
Officials said they feared the damaged spillway could unleash a 30-foot wall of water on Oroville, north of the state capital Sacramento.
|
|
The spillway, which had been opened just 13 times in its 80-year existence, had never before been opened twice in one year.
|
|
They urged federal officials to mandate concrete fortifications along the auxiliary spillway as part of the relicensing process for the dam's hydroelectric plant.
|
|
State officials said they need to use the spillway to control the rising water in Lake Oroville -- one of the state's key reservoirs.
|
|
And a Sacramento environmental group said they had urged officials to reinforce the spillway in 2005 because it didn't meet modern safety standards.
|
|
Engineers and environmentalists said problems like Oroville's damaged spillway could occur at many of the more than 1,000 dams that dot the state.
|
|
Hurricane Maria ravaged Puerto Rico, causing a major breach in the emergency spillway of the Guajataca Damand endangering the lives of 70,000 people.
|
|
The lower half of the spillway has concrete erosion, creating a gaping hole in a structure that is used for controlled releases of water.
|
|
Earlier inspection reports offer potential clues, including cracks on the spillway surface that if not properly repaired could let water tear through the concrete.
|
|
The dam has two spillways -- the primary and the emergency spillway -- which are channels to leak water out of the lake to prevent overflow.
|
|
Ron Stork, policy director with Friends of the River, a Sacramento environmental group, said state and federal officials were told to reinforce the spillway.
|
|
Cal Fire crews cleared a hillside area near the dam's emergency spillway of trees, rocks and other debris to reduce potential debris flows downstream.
|
|
It could be a huge problem for communities near the Oroville Dam, where a damaged spillway has prompted evacuations in case the dam overflows.
|
|
According to the outlet, a hole developed in the auxiliary spillway of the 770-foot-tall Oroville Dam, the tallest in the United States.
|
|
The situation shifted late Sunday night, when acting Water Resources director Bill Croyle said water had finally stopped pouring over the dam's emergency spillway.
|
|
The main spillway, which is lined, or paved, has a hole almost the size of a football field and at least 40 feet deep.
|
|
Chaotic escape Officials warned Sunday that a 30-foot "wall of water" could be sent rushing downstream if the eroding spillway were to collapse.
|
|
Also, Brown welcomed scrutiny after revelations in recent days that there had been warnings more than a decade ago about the troubled emergency spillway.
|
|
The FEMA spokesperson said the California governor would need to put in another request to the president to cover cost-sharing on spillway repairs.
|
|
Even so, engineers have been using the damaged primary spillway this week for significant outflows to lower the lake level as new storms approach.
|
|
In all the years since the dam was opened in 2171, the unpaved emergency spillway had never been tested, let alone used in anger.
|
|
This was dismissed on grounds that even if the emergency spillway suffered significant damage, it "would not affect reservoir control or endanger the dam".
|
|
In the meantime, experts aren't worried about the condition of the damaged spillway, saying it can still handle overflow waters should the need arise.
|
|
To release some of the excess water, dam operators opened the spillway for the very first time and filmed the event from the air.
|
|
The spillway has remained open since then, releasing freshwater into the Gulf of Mexico at rates in excess of 100,000 cubic feet per second.
|
|
Last month, water flowed over Oroville Dam's emergency spillway and caused significant erosion and risk of structural failure that led to massive evacuations downstream.
|
|
State authorities and engineers on Thursday began releasing water from the dam after noticing that large chunks of concrete were missing from a spillway.
|
|
The spillway doesn't open all that often, but this year it was opened twice, the first time in its history that that has happened.
|
|
The spillway protects communities near the Mississippi's mouth from flooding by releasing water from the river and reducing pressure on the flood-control system.
|
|
Over the weekend, managers had been inspecting the damaged main spillway and concluded it could withstand larger water flows, even with the giant hole.
|
|
When the emergency spillway showed signs of erosion, engineers feared a 30-foot-high section could fail, leading to the evacuation order on Sunday.
|
|
Or should he relieve the pressure by opening the spillway, purposely adding to the flooding of towns, homes and farmland for hundreds of miles.
|
|
"The water is coming," Mike Word, the director of emergency operations for Rankin County, said in a televised briefing before the spillway was opened.
|
|
In preparation, officials said they would continue to send water down the main spillway in hopes of dropping the lake's level by 1 feet.
|
|
Among them was Mike's Grande Burger which gave out free meals to the truck drivers, emergency personnel and others working at the hobbled spillway.
|
|
Powerful as it looks, the spillway probably wouldn't pull you down to the netherworld if for some reason you found yourself in the lake.
|
|
An earlier version of this article misstated the amount of water Lake Berryessa can hold before the excess begins to flow into its spillway.
|
|
But the dam will have to be rebuilt, with a new emergency spillway, at a cost expected to be about half a billion dollars.
|
|
This particular situation was partly caused by the opening of a spillway in Louisiana which brought "excessive" freshwater to the coastline, a Mississippi newspaper reported.
|
|
Earlier Monday, DWR officials denied that the state had ignored earlier concerns about the Oroville Dam's emergency spillway or had been lax in inspections there.
|
|
" Croyle, the acting director of DWR, defended the dam's emergency spillway design saying it was "built to the standards at the time [in the 1960s].
|
|
Why evacuation order was made A light flow of water began washing into the emergency spillway Saturday and the volume of water began to increase.
|
|
The acting director of the California Department of Water Resources, Bill Croyle, said he was "not familiar with 2005 documentation or conversation" about spillway concerns.
|
|
However, utilizing the emergency spillway—essentially an unlined hillside—is likely to send mud and other debris into the water of rivers and channels downstream.
|
|
This storm marked the first time since 2006 that Anderson Reservoir's spillway activated, producing heavy outflows that the San Francisco Chronicle likened to Niagara Falls.
|
|
The amount of water flowing into Lake Oroville is much less than the water allowed to flow out through a primary spillway in the dam.
|
|
DWR officials this week denied that the state had ignored earlier concerns about the Oroville Dam's emergency spillway or had been lax in inspections there.
|
|
The unlined emergency spillway — essentially a hillside — experienced significant erosion after the reservoir overflowed Saturday, at one point reaching an elevation capacity of 901 feet.
|
|
Last month, a spillway for America's tallest dam overflowed, drawing renewed awareness to the possibility of a breach on one of our country's aging dams.
|
|
Only twice in the mighty Hoover Dam's 80-year history has it used its spillway tunnels, and on both occasions they were damaged by cavitation.
|
|
Image: APFor three weeks in February, torrents of water rushed down the emergency spillway at Oroville dam, prompting fears that the entire structure would collapse.
|
|
Extensive rainfall in Northern California damaged the spillway of the Oroville Dam – the nation's tallest – and threatened numerous communities below the dam with massive flooding.
|
|
Our nation's locks and dams are crumbling, and save for catastrophic events like California's Oroville Dam spillway collapse earlier this year, the public hardly notices.
|
|
On Monday afternoon, crews dropped large bags filled with rocks into a gap at the top of the emergency spillway to rebuild the eroded hillside.
|
|
It excludes the costs of other contractors and the emergency response in the immediate aftermath of the spillway failure, which prompted fears of massive flooding.
|
|
Barring a major storm or equipment failure, Kiewit's 2000 workers and subcontractors are on track to finish pouring concrete on the main spillway by Nov.
|
|
Officials are keeping a wary eye on Lake Sabrina, southwest of Bishop, which on Thursday was roughly seven feet from the lip of its spillway.
|
|
The spillway caused a potential crisis in February 0000 during another period of heavy rain when erosion created a big hole in the concrete structure.
|
|
A day later, state officials noticed a hole forming in the spillway and prepared for the worst, ordering nearly 190,000 people to seek safer ground.
|
|
With more storms approaching, officials are effectively now in a race against time to lower the level of the lake and reinforce the hobbled spillway.
|
|
Crews have installed temporary cameras and lights along the spillway, so they can monitor the water around the clock as it flows down the chute.
|
|
The US Army Corps of Engineers this week opened Louisiana's Bonnet Carre Spillway to divert rising water away from New Orleans to sparsely populated areas.
|
|
High water levels at Lake Oroville this weekend prompted authorities to use the dam's emergency spillway for the first time in its nearly 50-year history.
|
|
Also, Sunday evening helicopters were being used to drop bags of rock and boulders into crevices of the emergency spillway erosion to prevent any further erosion.
|
|
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 the diverted water flowed into the emergency spillway for the first time in the nearly 50 years since it was built, it began to erode.
|
|
Officials are keeping an eye on the Oroville Dam after mandatory evacuations last week over concerns that an emergency spillway could fail and threaten nearby communities.
|
|
Authorities issued evacuation orders for at least 188,000 people near northern California's Lake Oroville Sunday after erosion at the emergency spillway threatened extreme flooding, CNN reports.
|
|
These efforts come amid mounting questions about why more had not been done to prevent spillway erosion after concerns were raised more than 10 years ago.
|
|
Officials that the primary spillway appears to be holding up despite its own erosion problems but reducing the outflows was still seen as a prudent measure.
|
|
Once Lake Oroville reached capacity, officials from California's Department of Water Resources began utilizing the dam's spillway—a structure that provides the controlled release of water.
|
|
Officials were alarmed enough to order 23,7003 National Guardsmen to stand by ready in case the spillway collapsed and brought down chunks of the dam itself.
|
|
Click here to view original GIFThis past weekend, hundreds of thousands of people were evacuated in anticipation of a potential spillway failure at the Oroville dam.
|
|
It appears that the bedrock below the undamaged part of the spillway is much stronger than the weathered material on the upper portion of the hillside.
|
|
Louisiana is expected to open the Morganza Spillway flood-control structure in early June to cope with the deluge, meteorologist Jeff Masters writes on Weather Underground.
|
|
The spillway allows the reservoir to be emptied faster in advance of a big storm, and the new rulebook will provide a framework for doing so.
|
|
The ruptured spillway had flooded 85 villages, affecting more than 63,000 people and submerging a section of highway, the Global New Light of Myanmar newspaper said.
|
|
FRONT PAGE An article on Tuesday about the problems at the Oroville Dam in California misstated the amount of water flowing over the dam's main spillway.
|
|
Once Lake Oroville reached capacity, officials from California's Department of Water Resources began utilizing the dam's spillway — a structure that provides the controlled release of water.
|
|
Trees and rocks would likely get washed away if the state uses the emergency spillway, causing potential debris and mud problems downstream to a state fish hatchery.
|
|
DWR reiterated Sunday that "Oroville Dam itself is sound," explaining that the dam built in the late 1960s is actually "a separate structure" from the emergency spillway.
|
|
Authorities lifted a three-day mandatory evacuation order in Northern California that had sent nearly 200,000 residents away following fears Oroville Dam's damaged emergency spillway might fail.
|
|
The primary spillway was designed to divert rising water out of the dam, but damage to the channel was discovered Tuesday just as major storms were approaching.
|
|
Officials are also keeping an eye on the Oroville Dam, after there were mandatory evacuations last week amid concerns an emergency spillway could fail and threaten communities.
|
|
Croyle said he was "not familiar with 2005 documentation or conversation" about spillway concerns and emphasized the efforts underway to understand the current dynamics of the dam.
|
|
The report also warned of additional rain in the forecast, adding that the Guajataca Dam spillway continued to erode and a flash flood watch was in effect.
|
|
The evacuation order was issued after engineers noticed a hole in the spillway, in the event that "the worst-case scenario came into fruition," said the sheriff.
|
|
Workers are shutting down water flows to the damaged Oroville Dam spillway in California in order to clear debris and examine the structure, the Sacramento Bee reports.
|
|
State officials worked to plug a hole in the flood-control spillway and put the estimate to repair the dam at about $1.1 billion back in 2018.
|
|
The state also incurred more than $100 million in costs earlier this year as workers dropped boulders and concrete into holes created by the damaged emergency spillway.
|
|
"The retaining wall of the spillway sank into the foundation about 4-5 feet, causing the flooding, but the main dam is intact," said Kaung Myat Thein.
|
|
But decades later, as the spillway failure at Lake Oroville demonstrated in February, many of California's dams are now confronting the stresses of age and extreme weather.
|
|
The final safety valve is a spillway—three hundred feet wide, half a mile long—that the dam's controllers can throw open to prevent an imminent breach.
|
|
Authorities were preparing to release water through its spillway as early as Monday afternoon, the first time in 20 years that would have happened, CBS 13 said.
|
|
That forced officials, for the first time in the 49-year history of the dam, to temporarily use an emergency spillway, an unlined hillside prone to erosion.
|
|
Water was flowing at the rate of 100,1003 cubic feet per second over the main spillway, which has a hole of its own but is not worsening.
|
|
Mr. Strain praised the Army Corps's handling of the current situation, saying that not opening the spillway would threaten the structure's integrity and thousands of acres downstream.
|
|
Damage to California's Oroville Dam concrete spillway this week has forced state engineers to consider alternatives to release water as new storms come into the Northern California region.
|
|
Without that new dam, the Oroville Dam's auxiliary spillway was designed to be used in in a controlled, infrequent way and not in an emergency capacity, they said.
|
|
The emergency spillway, which is an embankment covered with trees, is a last resort and was used for the first time in its 48-year history on Saturday.
|
|
Completed in 280, the aging Oroville Dam was suddenly holding back a reservoir at 21862 percent of its capacity, forcing operators to relieve the pressure via a spillway.
|
|
The Thanneermukkom barrage, built in 1975 to block seawater, and a spillway constructed in 1955 to drain off floodwater extended the rice season, also pushing up annual yields.
|
|
At this point, the Department of Water Resources expects to get water levels in the Oroville River low enough that the emergency spillway won't need to be used.
|
|
Then the rising water topped over the earthen backup spillway, which has a concrete top, for the first time in the dam's 50-year history over the weekend.
|
|
Early Saturday, an adjacent emergency spillway was also put into use, the first time water flowed over it since the dam was finished in 1968, department officials said.
|
|
Workers have rushed to fix the damaged embankment of the Oroville Dam north of Sacramento, which this past week was weakened by water discharged from an emergency spillway.
|
|
Trucks last week rumbled up the winding roads to the 770-foot-high dam, carrying rocks and other materials as crews continued to shore up an eroded spillway.
|
|
For the first time in the nearly 50 years since it was built, water was diverted into the emergency spillway, which was covered with brush, trees and rock.
|
|
Spillway boat ramps and pedestrian access to the walkway across the top of the dam are expected to reopen in the summer of 2019 with improved safety measures.
|
|
Engineers conducted two test runs with water flows on Wednesday, checking to see if the spillway can handle the strength of about 20,000 cubic feet per second of water.
|
|
But because the water levels are so high, the emergency spillway — which appears to be eroding — could unleash a wall of water onto the communities below if it collapses.
|
|
The hole found Sunday in the emergency spillway — essentially a natural hillside of soil, rock and brush — led engineers to shift major water flows away from this unlined channel.
|
|
The main spillway is damaged from significant concrete erosion but was being utilized to release water from the swollen dam Monday, according to the California Department of Water Resources.
|
|
The hole found Sunday in the emergency spillway — essentially a natural hillside of soil, rock and brush — led engineers to shift major water flows away from this unlined channel.
|
|
Experts said problems like the cracks in the concrete spillway and spots in nearby areas where water seeped from the reservoir through a hillside were common issues with dams.
|
|
Ahead of possible use of the emergency spillway, there were frantic efforts over the last few days, as teams worked to prepare the hillside for a deluge of water.
|
|
Water began flowing over the emergency spillway at the Oroville Dam in Northern California on Saturday for the first time in its nearly 50-year history after heavy rainfall.
|
|
The dam's primary spillway also has major erosion damage but there's a chance it may need to be used next week to reduce water levels as more snow melts.
|
|
The Bonnet Carre Spillway, a man-made sluice about 30 miles upriver from New Orleans that diverts water to Lake Pontchartrain, is not put into service in most years.
|
|
With fears that the spillway of the Oroville Dam, the highest in California, might give way, around 180,000 people living below the dam were ordered to leave their homes.
|
|
On Monday afternoon, crews began dropping large bags filled with rocks into a gap at the top of the emergency spillway in a bid to rebuild the eroded hillside.
|
|
The spillway has been rebuilt to handle water flowing at a rate of 270,000 cubic feet of water per second, significantly more than officials would ever expect to release.
|
|
"The Oroville main spillway was designed and constructed using 21st century engineering practices and under the oversight and guidance from state and federal regulators and independent experts," Ledesma said.
|
|
The water could not be drained fast enough, and the main spillway had developed a hole the size of a football field and 40 feet deep due to erosion.
|
|
"Any spillway -- primary or emergency -- usually has some kind of protection, a concrete basin," said Blake Paul Tullis, a professor of Civil and Environmental Engineering at Utah State University.
|
|
That said, state workers Thursday were clearing the hillside of vegetation, rocks and other possible debris in case the emergency spillway was needed to handle the additional water from rains.
|
|
California officials worked frantically into the night Sunday to evacuate thousands of residents downstream from the Oroville Dam after a hole on an emergency spillway raised fears of flash floods.
|
|
State and local officials worked into the night Sunday to evacuate thousands of residents downstream from the dam after a hole in an emergency spillway raised fears of flash floods.
|
|
"If the emergency spillway were to fail, it would send a 30-foot wall of water downstream, resulting in catastrophic flooding," Brown said in his Monday letter to the president.
|
|
Indeed, state officials Friday at a press conference indicated they were unlikely to use the emergency spillway since the damaged primary channel still was able to release sufficient water levels.
|
|
The California Department of Water Resources said it is releasing as much as 100,000 cubic feet per second from the main, heavily damaged spillway to try to drain the lake.
|
|
California water officials were draining water from the Oroville Dam to relieve pressure on a damaged spillway that threatened public safety and led to a sudden evacuation order on Sunday.
|
|
Authorities ordered people to leave the area on Sunday when a hole developed in an eroded area of the spillway, raising concerns that it could fail and flood communities downstream.
|
|
The problem, on Sunday, inspectors found that the emergency spillway was also eroding and if it fails, it could cause flash flooding all the way to Sacramento, 210 miles away.
|
|
They dropped huge white bags filled with rocks into the hole that had opened up in the spillway, and deposited large chunks of concrete to protect it from future erosion.
|
|
The heavy rain and melting snowpack threatened to undermine a spillway at one of the largest dams in the country, which prompted the evacuation of 188,000 residents earlier this week.
|
|
" The DWR wrote on its Facebook page, "Officials are anticipating a failure of the Auxiliary Spillway at Oroville Dam... Residents of Oroville should evacuate in a northward direction, toward Chico.
|
|
Aerial photos of the Oroville dam show the bottom portion of the spillway completely ripped to shreds, and a dramatic canyon wall with steep cliffs running along side of it.
|
|
At Bonnet Carré Spillway east of Norco (the area's last line of protection against springtime river floods breaching the levees), the scientists detected upwards of 1.6 inches of annual subsidence.
|
|
Simply fixing the recent damage at the main spillway at Oroville Dam alone could cost an astounding $100 million to 200 million, according to the state's Department of Water Resources.
|
|
Mass Evacuation in California Over Oroville Dam RiskAround 188,000 people in Northern California were told to evacuate their homes Sunday night over fears the Oroville Dam's emergency spillway could collapse.
|
|
The authorities in Northern California raced to evacuate tens of thousands of people on Sunday night in fear of the possible failure of an emergency spillway at the Oroville Dam.
|
|
Workers dropped huge white bags filled with rocks into the hole that had opened up in the spillway and deposited large chunks of concrete to protect it from future erosion.
|
|
Erosion caused by the hole in the side of the main spillway appeared to have abated by Monday, and it was back to more or less normal operations, officials said.
|
|
Conservation groups Friends of the River and the Sierra Club argued in 2005 that the dam's emergency spillway should be better fortified and risked severe erosion when water levels rose.
|
|
Specifically, Honea said engineers had reduced the level of the reservoir below the top of the emergency spillway so the erosion to the area in front of it could be halted.
|
|
Unexpected erosion chewed through the main spillway during heavy rain earlier this week, sending chunks of concrete flying and creating a 200-foot-long, 30-foot-deep hole that continues growing.
|
|
"I can't believe how much work...they've done in the last couple of days to move material into the area below the emergency spillway," said Croyle, whose agency operates the dam.
|
|
The dam operators opened the spillway Monday afternoon, which will mean higher water levels in the river system for a while, says Jon Ericson with the California Department of Water Resources.
|
|
The erosion of the Oroville Dam's emergency spillway, which triggered the evacuation of 188,000 people, was just the first in a series of notable dam-related events in California last week.
|
|
"Officials are anticipating a failure of the Auxiliary Spillway at Oroville Dam within the next 60 minutes," wrote the California Department of Water Resources on Sunday night at around 5PM PST.
|
|
Erosion eventually caused a 200-foot-long (60-meter-long), 30-foot-deep hole to form near the center of the spillway, a structure used to control the release of water.
|
|
Residents below the dam were ordered from their homes on Sunday when an emergency spillway that acts as an automatic overflow channel appeared on the brink of collapse from severe erosion.
|
|
However, a FEMA official told the Sacramento Bee that the agency turned down the requested amount since there was damage to the spillway even before heavy rainfall eroded the gateway's surface.
|
|
Erosion caused by the hole in the side of the main concrete spillway appeared to have abated by Monday, and it was back to more or less normal operations, officials said.
|
|
Except this created a new — and even more worrisome — dilemma: The water began eating away at the ground beneath the top of the auxiliary spillway, carving deep gullies into the earth.
|
|
Water authorities had been relieving pressure on the dam through the concrete-lined primary spillway last week, but lake levels rose as storm water surged in and engineers moderated its use.
|
|
A California dam's spillway appears to have stabilized, but evacuation orders remain in place for more than 180,000 people as state authorities try to make emergency repairs before more rains come.
|
|
Three local environmental groups filed a motion with the Federal Energy Regulatory Commission in 2005 urging federal officials to reinforce the Oroville dam's emergency spillway with concrete, the Mercury News reported.
|
|
Officials in California were racing against the weather Tuesday, struggling to shore up the Oroville Dam's emergency spillway before more rains pummel the area and place the structure under even greater stress.
|
|
The erosion at the head of the emergency spillway threatens to undermine the concrete weir and allow large, uncontrolled releases of water from Lake Oroville, the California Department of Water Resources said.
|
|
Acting Director Department of Water Resources Bill Croyle said officials will be able to assess the damage to the emergency spillway now that the water is no longer spilling over the top.
|
|
It would be the first time in history the spillway was used twice in one season, Major Jordan Davis, a US Army Corps of Engineers spokesman said in a press conference Thursday.
|
|
Dump trucks and cement mixers shuttled in material as workers rushed to fortify the damaged emergency spillway, which allows excess water to run out when the lake level rises above 103 feet.
|
|
The evacuation was ordered Sunday after a massive hole was discovered in an emergency spillway -- which catches excess water when Lake Oroville's water level rises to overflow the dam -- threatening communities downstream.
|
|
The question facing the team of independent experts appointed by FERC in the immediate aftermath of the near-disaster is why, after all these years, did the Oroville Dam's main spillway fail?
|
|
The cavitation that afflicted the Oroville Dam's main spillway could have been caused by shrinkage in the 50-year-old concrete, along with residual roughness stemming from repairs done over the years.
|
|
This article has been modified to clarify that the Bonnet Carre Spillway is one of a set of floodways along the Mississippi River designed to move water to the Gulf of Mexico.
|
|
The approach is also being incorporated into operating rules at Folsom Reservoir, operated by the US Bureau of Reclamation near Sacramento, as part of a new flood-control spillway recently completed there.
|
|
Conservation groups Friends of the River and the Sierra Club also raised issues, requesting that the dam's relicensing be contingent on stronger fortification of the emergency spillway — which nearly failed this week.
|
|
State officials used 40 trucks carrying 30 tons of rock per hour to reinforce the eroded area around the emergency spillway while two helicopters dropped rock and other materials into the breach.
|
|
The dam's spillway was opened, unleashing a surge of additional water into the already swollen river, fueling one of the most severe floods to hit the central part of Mississippi in decades.
|
|
Authorities then discovered a massive hole in the emergency spillway -- essentially a large embankment -- and evacuated about 9003,2900 people out of fear that an uncontrolled release of water could flood downstream communities.
|
|
"The spillway is necessary to maintain reservoir operations, given the immediate forecast of continued rain for the next two days and also in preparation for the remaining runoff season," the DWR said Wednesday.
|
|
Jerry Brown on Monday evening requested federal assistance with the Oroville Dam emergency spillway crisis as mandatory evacuation orders remained in effect for about 188,000 residents downstream from the nation's tallest earthen dam.
|
|
The emergency spillway at California's swollen Oroville Dam was activated Saturday, as water levels from heavy rains this week caused the reservoir to rise above its capacity during an unusually plentiful rain season.
|
|
The failure of the concrete base at Oroville Dam's primary spillway has put the spotlight on the state's aging infrastructure at a time when Trump is talking about increasing U.S. spending on infrastructure.
|
|
Crews from the local power company, PG&E, removed several electrical lines using crews carried by helicopters and there also were plans to move transmission towers from the path of the emergency spillway.
|
|
"Our crews are working around the clock, 24/7, to try to get as much rock as possible onto the damaged spillway before the next storms come," Cal Fire spokesman Josh Janssen said.
|
|
But they soon noticed unusual flow patterns, and when they stopped the outflow, they saw that the concrete had buckled and a gaping, widening crater had formed in the middle of the spillway.
|
|
Further south in the Central Valley, about halfway between Modesto and Yosemite National Park, the spillway gates of the Don Pedro reservoir opened on Monday afternoon for the first time in two decades.
|
|
With yet more storms on their way, the main spillway of the dam was opened, so the fresh runoff from Lake Oroville's 803,000 square mile (15,500 square kilometre) catchment area could be accommodated.
|
|
If erosion undercuts the 251,20063-foot-long concrete lip running along the top of the emergency spillway, a 22006-foot wall of water could come crashing down on the residents of nearby towns.
|
|
The department said it preferred not to use the emergency spillway because it would dump water onto trees and put debris into the Feather River, a source of water for parts of California.
|
|
The Bonnet-Carre spillway, for example, was open for 76 days between January and June, and like other spillways, it "will be investigated as a potential contributing factor to this UME," noted NOAA.
|
|
Authorities issued the evacuation order on Sunday, saying that a crumbling emergency spillway on Lake Oroville Dam in north California could give way and unleash floodwaters onto rural communities along the Feather River.
|
|
As the damaged spillway along with the backup channel struggled to handle the influx of water earlier this year, authorities feared that Lake Oroville was on the verge of overflow, threatening communities downstream.
|
|
Plans call for the entire main spillway to be demolished and reconstructed by 2019 with 2.5 feet of erosion-resistant, rebar-reinforced concrete on top of five to 19693 feet of leveling concrete.
|
|
The threat led the U.S. Army Corps of Engineers in Louisiana to make plans to open a spillway around New Orleans on Sunday to keep the volume of the river flow in check.
|
|
Peace River Hydro Partners, jointly owned by Acciona SA and Samsung C&T, was awarded the C$1.75 billion contract for civil works, and is bidding for the generating station and spillway contract.
|
|
While the Addicks Reservoir breached the top of its emergency spillway and began flowing uncontrolled, the water levels have not reached the 109.5 foot level that U.S. Army Corps of Engineers Galveston Col.
|
|
The crisis started after big storms and mountain runoff filled Lake Oroville beyond its capacity and a large hole opened up in the dam's main spillway that releases water into the Feather River.
|
|
On Saturday, officials began relying on the backup auxiliary spillway, which had never been used since the dam's construction in 2000, but soon determined that that structure was also at risk of failing.
|
|
On Saturday, officials began relying on the backup auxiliary spillway, which had never been used since the dam's construction in 1968, but soon determined that that structure was also at risk of failing.
|
|
"There was significant concern that it would compromise the integrity of the spillway, resulting in a substantial release of water," Kory Honea, the Butte County Sheriff, told reporters at a press conference Sunday evening.
|
|
Inspectors with the state agency that both operates and checks the dam, the nation's tallest at 770 feet, walked the half-mile-long spillway in 2014 and 2015 and did not find any concerns.
|
|
A mandatory evacuation order was ordered Sunday from authorities after fears the 48-year-old dam's emergency spillway could suffer critical failure and lead to the release of large, uncontrolled amounts of water downstream.
|
|
The erosion of the emergency spillway is dangerous because "when you start to erode the ground, the dirt and everything else starts to roll off the hill," said Kevin Lawson, California Fire incident commander.
|
|
"We can't get the flows much lower until we're at a position of the storms coming in and out that we feel comfortable turning off the water at that spillway," the state official added.
|
|
Those words have come home to haunt both FERC and California's Department of Water Resources, the dam's operator, which continued to insist (until disaster struck) that the emergency spillway was up to the job.
|
|
Butte County Sheriff Korey Honea said at a separate news briefing that he was told by experts earlier on Sunday that the hole that was being created in the spillway could compromise the structure.
|
|
Oroville Dam Repair cost: more than $274 million Under heavy rainfall, the primary spillway that handles the overflow at the Oroville Dam eroded and formed a hole almost the size of a football field.
|
|
The trouble at Oroville Dam began in early February, when a massive crater opened up in the main spillway, a 230,803-foot concrete chute that releases water from Lake Oroville, California's second-largest reservoir.
|
|
The region is expecting more storms by Thursday, so workers have been rushing to fortify the emergency spillway before water reservoir levels begin rising again and more water starts pouring over the eroded hillside.
|
|
"The operation of the plant has been interrupted, spillway tests have been carried out and the water intakes have been closed to preserve the equipment," Furnas said in s statement issued late on Tuesday.
|
|
Water began flowing over an emergency spillway at a major Houston flood-control reservoir on Tuesday, the Army Corps of Engineers said, adding to flooding in the area about 15 miles west of downtown.
|
|
That would put the lake level a little more than 40 feet below the top of the spillway, and provide some wiggle room for the level to increase during the next round of storms.
|
|
During the two phases of the repair, crews worked to cover the spillway with structural concrete, install cutoff walls on the sides and reinforce the concrete with 12.4 million pounds of steel, officials said.
|
|
Ron Stork, policy director of the conservationist nonprofit Friends of the River and a flood management expert, said he doesn't anticipate immediate problems with the spillway but believes more repairs need to be done.
|
|
The authorities believe that they are lowering the reservoir enough that the emergency spillway will not be needed during the newest round of storms, but they are racing to fix it just in case.
|
|
At least 2000,2200 people remain under evacuation orders after Northern California authorities warned an emergency spillway in the country's tallest dam was in danger of failing Sunday and unleashing uncontrolled flood waters on towns below.
|
|
Department engineer and spokesman Kevin Dossey told the Sacramento Bee the emergency spillway was rated to handle 250,000 cubic feet per second, but it began to show weakness Sunday at a small fraction of that.
|
|
"What we have to do is clear out the debris from the diversion pool, the area below the spillway," said Chris Orrock, a spokesman for DWR, the state agency owning and operating the Oroville facility.
|
|
California Department of Water Resources Acting Director Bill Croyle said he was "not familiar with 2005 documentation or conversation" about spillway concerns and emphasized the efforts underway to understand the current dynamics of the dam.
|
|
The evacuation Sunday occurred after state and local officials grew concerned the hole near the top of the emergency spillway could cause a 30-foot wall of water down to the Feather River and tributaries.
|
|
He also theorized the failure may have been tied to California's five-year drought: The aging spillway could have weakened as it underwent contractions due to the sudden heavy soaking following years of dry weather.
|
|
"This has been America's wettest year on record in 124 years," said Matt Roe of the Army Corps of Engineers, who greeted me out at the Bonnet Carre Spillway, one hour northwest of New Orleans.
|
|
The Army Corps opened the Bonnet Carre Spillway in March and dumped trillions of gallons of polluted river water into some of Louisiana's best saltwater fishing estuaries until the gate was closed on April 11.
|
|
State authorities and engineers on Thursday began carefully releasing water from the Lake Oroville Dam some 65 miles (105 km) north of Sacramento after noticing that large chunks of concrete were missing from a spillway.
|
|
Heavy rain and snow in the Midwest caused the Army Corps of Engineers to open the Bonnet Carré Spillway, about 33 miles northwest of New Orleans, for a record 118 days last winter and spring.
|
|
"The concern is that erosion at the head of the auxiliary spillway threatens to undermine the concrete weir and allow large, uncontrolled releases of water from Lake Oroville," the California Department of Water Resources said Sunday.
|
|
Here are some of the key stories CNBC is following this hour: Nearly 200 thousand people remain under evacuation orders this morning as California officials try to fix an emergency spillway at the nation's tallest dam.
|
|
According to the Santa Clarita Valley Water District website, preliminary readings indicated the reservoir was at 105.5% of capacity on Tuesday afternoon and the water level was almost 4 feet above the top of a spillway.
|
|
Oroville Dam spillway still a concern While Southern Californians will be seeing the bulk of their rain before the end of the weekend, those in Northern California can expect heavier rain late Sunday and into Monday.
|
|
In the main spillway, which is lined, or paved, erosion has caused a hole almost the size of a football field and at least 231 feet deep to form in the lower part of the channel.
|
|
"This next storm won't pose a risk to the emergency spillway or the work we're doing," William Croyle, acting director of the California Department of Water Resources said at a noon press briefing in Oroville, California.
|
|
Meanwhile, to take pressure off the weir, the main spillway was opened wide, despite fears that the 2200-ft gash in the concrete could spread further up the chute and breach the gates at the top.
|
|
Without a true sense of scale, it looks just like the drain in your bathtub, but from a drone's bird's eye view, the opening to this spillway looks more like a black hole sucking everything in.
|
|
What to watch: Floodwaters are slowly making their way down the Mississippi River toward Louisiana, where the river is expected to crest at the Morganza Spillway by June 2, at the second-highest level on record.
|
|
We've seen the Bonnet Carre Spillway, a flood control mechanism to manage a high Mississippi River, opened twice in one year and in two consecutive years for the first time in its almost 90-year history.
|
|
More rain was forecast for as early as Wednesday and through Sunday, according to the National Weather Service, but the state Department of Water Resources said the upcoming storms were unlikely to threaten the emergency spillway.
|
|
The Army Corps of Engineers has increased the release of water into the Arkansas River from the Keystone Dam in Oklahoma to 275,000 cubic feet per second, hoping to keep floodwaters from overtopping the dam's spillway.
|
|
State officials had been fixated on the troubles at Lake Oroville, about 70 miles north of Sacramento, since last Tuesday, when part of its main spillway caved in during water releases into the Feather River below.
|
|
Brown's request to President Donald Trump for a federal emergency declaration to assist in the potential failure of the Oroville Dam emergency spillway is currently under review, according to a spokesperson for the Federal Emergency Management Agency.
|
|
The primary spillway at the nation's tallest earthen dam also has significant erosion to its concrete liner but is still being used for outflows to relieve the swollen dam of water ahead of several major storm systems.
|
|
But no sooner had water from the reservoir begun to gush down the paved spillway than a huge crater—big enough to swallow a house—was torn in the concrete half way down the 21928,2400-ft chute.
|
|
Because the auxiliary spillway had never been used before, and due to the tremendous amount of water spilling into it, officials feared a total collapse of the dam system, resulting in the evacuation order earlier this week.
|
|
Now that California is finally getting a heavy dose of rain, the spillway at Napa's Monticello Dam—referred to as the "Glory Hole" by the locals—is working overtime to manage the water levels in Lake Berryessa.
|
|
On Monday, water could be seen gushing from the main spillway as dam operators for the California Department of Water Resources continued controlled releases through the chute into channels that route the water away from populated areas.
|
|
Compared to the original 1960s design, the new spillway will have more rebar, stronger and thicker concrete, vinyl water stops inside of joints and a heartier drainage system — all with the concrete anchored into bedrock, Petersen said.
|
|
On Sunday, authorities ordered some 188,000 people around Oroville to evacuate their homes over concerns that the dam's emergency spillway could fail and an onrush of water out of the reservoir could flood nearby towns and roads.
|
|
In the aftermath, managers were reluctant to send water racing down this main spillway, lest the damage get worse: But the water levels in the Oroville Reservoir kept rising and rising, and it had to go somewhere.
|
|
That was terrifying: If the 2000-foot-high concrete barrier at the top of the auxiliary spillway collapsed, billions of gallons of water would start bursting from the reservoir all at once, swamping the Feather River below.
|
|
Despite concerns of an imminent breakdown earlier in the night, officials said late Sunday that the water level at the Lake Oroville reservoir had dropped, halting water flow over the emergency spillway and temporarily stabilizing the situation.
|
|
Construction crews have been working to rebuild the spillway at the Oroville Dam in Northern California since May 2017, and have restored its "full functionality," said Joel Ledesma, deputy director of the California Department of Water Resources.
|
|
Yet when public interest groups warned of such a threat in 2005, state and federal officials rejected their call to line one spillway with concrete, saying it was unnecessary, The San Jose Mercury News reported on Sunday.
|
|
Engineers don't know what caused the cave-in, but Chris Orrock, a spokesman for the state Department of Water Resources, said it appears the dam's main spillway has stopped crumbling even though it's being used for water releases.
|
|
With the work being done to increase outflow, Bill Croyle, the state's acting director of water resources, didn't expect that the emergency spillway will be needed, particularly since less rainfall is expected this week than in previous storms.
|
|
More than 188,000 people who live near the dam were told to evacuate on Sunday as workers scrambled to patch a giant hole in the spillway that lets out excess water when the lake level got too high.
|
|
Alarmed, the dam's operators resorted to the one backup measure they had hoped to avoid: let the water in the reservoir rise until it flowed over a weir leading to an unpaved emergency spillway off to the side.
|
|
Authorities issued the abrupt evacuation orders in the mid-afternoon, saying that a crumbling emergency spillway on the Lake Oroville Dam could give way and unleash raging floodwaters onto a string of rural communities along the Feather River.
|
|
They argue federal regulators and the courts should require the state to better fortify the emergency spillway, to reimburse the county for dam-related costs, and to more carefully examine the effects of climate change on the dam.
|
|
Meanwhile, water could be seen gushing from the main concrete spillway as dam operators for the California Department of Water Resources continued controlled releases through the paved chute into channels that route the water away from populated areas.
|
|
The culprit at Oroville was a faulty emergency spillway, used for the first time since the dam was opened after days of drenching storms, driven by what are known as atmospheric rivers, that filled the reservoir to capacity.
|
|
So, for the first time in the dam's 287-year history, water began pouring over the top of the auxiliary or "emergency" spillway to the left of the main concrete chute — a feature that serves as a last resort.
|
|
AROUND THE WEB: The water level at Lake Oroville in California is falling, but evacuation orders are still in place downstream due to a possibility that corrosion could cause the lake's emergency spillway to fail, the Sacramento Bee reports.
|
|
For the nearly 200,000 people evacuated from Oroville and other points downstream from the Oroville Dam, this means an anxious and indefinite stay away from home due to the danger of sudden flooding if an auxilliary spillway gives way.
|
|