Emergency: California’s Oroville Dam Spillway Near Failure, Evacuations Ordered

Breitbart ^ | Feb 12, 2017 | Joel B. Pollak1

[janetjanet998]

The California Department of Water Resources issued a sudden evacuation order shortly before 5 p.m. Sunday for residents near the Oroville Dam in northern California, warning that the dam’s emergency spillway would fail in the next 60 minutes.

The Oroville Dam is the highest in the nation.

[Yulee]

Remember Katrina. A Dem Governor, a Dem Mayor catastrophe,and then the Dems blamed Bush.

So is this a wash and repeat. They've been calling for a evacuation for days. If the area is destroyed, it will be no different than those areas destroyed by tornado, and hurricanes elsewhere.

BUT..since it is California, the Dems will scream and shout that it's Trump's fault, and the Republicans. This will be par for the course.

[KC Burke]

Plus you need to add in rising the power plant lower level and its equipment. That is your relief valve and needs to be restored and repaired first in my opinion. When working, it can release about 20,000 cfs, a third of what we are releasing now. When the main spillway is unusable as under repair, the only relief valve you have, as I understand it, is what comes out of that area of the dam. That needs to start in ten days as this last river of rain passes.

[KC Burke]

darn spell check changing words “add in repairing the power plant” — strike “rising.”

[EarthResearcher333]

>>Failure discussion continuation: UC Berkeley professor, engineering expert: Known Cracks & Defects not fixed properly.<<

Below is another perspective from Robert Bea, UC Berkeley, commenting on a known trouble spot in the main spillway (see 2013 image below).

However, I believe there is more to it than just the surface concrete slab crack repairs (i.e. detected defects & enacted repairs).

Engineering Professor (emeritus) Robert Bea gives a form of a simplified answer on associating repeated defect repairs & the breach. The discussion should have delved deeper. (note: I realize the prof was asked to review reports for the interview - the prof did not have any input to these original 14 reports generated by the Division of Safety of Dams- part of DWR).

How? The recurrence of these cracks should have triggered a more thorough level of expertise in analysis - such as bringing in expertise in an investigation on other mechanisms at play: such as slumping or even "voiding" underneath the slab(s), from excessive scour erosion or subsurface material integrity issues, including a failure of one of the "herring bone" angled drain pipes. Any indicator that may be causing unseen stresses on the concrete.

Why? Because repeated cracking means (1) the repairs were insufficient to stop the cracking and (2) there is likely another causal mechanism at play.

(note: this of course is giving the benefit of the doubt on competency of the expertise applied in the "crack repairs").

NOTE (error correction): Professor gives an incorrect length comment of the spillway of 1,730ft (spillway length is stated to be at/near 3,055ft).

=== Article excerpt

http://www.govtech.com/em/disaster/Alarms-raised-years-ago-about-risks-of-Oroville-Dams-spillways.html

excerpt:

Alarms Raised Years Ago About Risks of Oroville Dam's Spillways

The cratering of the main spillway — which spiraled into the current crisis in Butte County — occurred in a spot where cracks and other defects had been found repeatedly since 2009, said Robert Bea, a professor emeritus and engineering expert at UC Berkeley.

But the defects do not appear to have been adequately repaired or resolved by the state Department of Water Resources, which runs the dam, and the faulty work probably resulted in the fissure that opened up last week on the 1,730-foot-long spillway, Bea said.

“My God, we had evidence that there was trouble going back to 2008, 2009,” said Bea, who at The Chronicle’s request reviewed 14 dam inspections from 2008 to 2016 conducted by the Division of Safety of Dams, which is part of the Department of Water Resources.

“Yes, they had detected the defects (in the main spillway) and yes, they had put into gear remedial measures,” Bea said. “Were those repairs sufficient? No. The result was a breach.”

=====

Image of "repeated trouble spot": This was in 2013. This trouble spot is at the location of the "access road" (2,039ft) just at/near where the failure occurred.

Image of normal sealing and repairs at the bottom of the Main Spillway. Notice the "water seepage" from the cracks under repair. This identifies that water flows upward from below the slabs. When the spillway has high water pressure forces from heavy volume waterflow in spillway operation, the flow reverses to under the spillway from high pressure. Thus the need for the extensive drain piping designed into & underneath the concrete slabs. The higher the pressure, from more spillway cfs, the more sub waterflow under the slabs. Increased drainage, under pressure, reveals a "jetting" of water in the drain outlets in the sidewalls. Thus, as dam expert Scott Cahill pointed out -a Good Sealed spillway should have very little waterflow coming from the sidewall drains.

[spokeshave]

Did you all see the latest report...mandatory safety evacuation...

Looks like a false report...re-cycled videos from last week

[EarthResearcher333]

Please point out where, and the time stamp, does either of these youtube’s identify “Large hole discovered under the emergency spillway”.

Thanks in advance.

[EarthResearcher333]

Ok.. thanks.

[mad_as_he$$]

Has anyone else noticed that there doesn’t seem to be any rebar in the spillway construction?

[mewzilla]

If there is no mesh/rebar/doweling that may be because standard practice when the spillway was built permitted that.

[mad_as_he$$]

I was working construction not long after the dam was built, it was buildings, but every concrete pour had steel in it - and I mean every one including sidewalks.

[mewzilla]

FWIW, I was checking CA codes and found plain concrete was okay for some usages many moons ago.

[mewzilla]

Just ran across something called the California Bearing Ratio. That’s for roads, I guess. Wonder if it would apply to spillways and, if so, if that has any bearing (ha ha) here...

[bert]

to find something really pertinent, you should research the 100 year flood and the resulting river flow rate and the design capacity of the spillway.

It is certain that the spillway capacity was under designed. Had it been somewhat larger, the problem would not exist

[KC Burke]

I never built a Lake/Dam this size in my career. As I focused on buildings, storm water structures were the incidental size. That being said, aprons, large “lay-down” areas, road beds, all were often built with the main slab segments not having reinforcing in the main body or the segment, but instead having dowels and reinforcing bars at the joints acting as “load transfer bars. These bars in the body of the slab were often smooth and set to slip for movement and then along the perimeter joints deformed bars to lock the segments together.

Building footings, walls, grade beams and structural members all have reinforcing steel throughout. Slabs on grade have temperature mesh except in heavy load bearing instances.

[KC Burke]

The CBR is a standard utilized when you know the sub-soil bearing characteristics and the type of traffic moving over a paving profile of asphaltic paving or concrete paving to come up with a design thickness for pavement and substrate.

[maggief]

http://www.orovillemr.com/general-news/20170222/lake-oroville-water-level-on-the-decline-brown-makes-unannounced-visit

The dam also got an unannounced visit by Gov. Jerry Brown Wednesday, even though he had earlier said he didn’t see a reason to, “hover in and mug for the media.”

His press office said he visited the command center and thanked the people working there. Photos of the visit were posted on social media, including one of him standing above the main spillway with acting Department of Water Resources Director Bill Croyle.

U.S. Sen. Kamala Harris is scheduled to visit the dam Thursday, but again the media is being excluded “for logistical reasons.”

Gov. Brown Press OfcVerified account ‏@GovPressOffice Follow More W/weather & #OrovilleSpillway situation stabilizing, @JerryBrownGov thanks command ctr team, surveys ongoing work + CA flood control system

[meyer]

Moonbeam goes on a field trip.

[maggief]

The looks on faces of people working there ...

Repost:

http://www.usatoday.com/story/news/politics/2017/02/19/oroville-dam-president-trump-governor-jerry-brown-feud-funding-conservative/98129510/

Oroville Dam exposes rift between conservative town, coastal liberals

[maggief]

Oh, boy ...

http://www.sacbee.com/news/politics-government/capitol-alert/article134386029.html

Amid Oroville emergency, California Legislature moves to make flood-control fixes

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.

Amid the ongoing crisis at Oroville Dam, lawmakers have taken only tentative steps so far. The first oversight hearing to review what happened in Oroville is scheduled for next week, and the Senate leader is proposing a one-time funding source for flood protection efforts.

Broader solutions for California’s aging flood-control facilities will likely not emerge for months, until at least the current emergency passes. But long-standing disagreements over how best to resolve the compounding water problems facing the state are already resurfacing, pointing to the challenges ahead for a deal when tax revenue is tight and budget commitments vast.

“The state of California is excellent at reacting. We’re just not very good at being proactive,” said Sen. Anthony Cannella, R-Ceres. “At some point, we’ve got to start spending some money on these things.”

An initial plan to provide $500 million in competitive grants to local and regional agencies for flood protection is forthcoming from Senate President Pro Tem Kevin de León. The money would be added to the plan for a $3 billion parks and drought recovery bond that de León, D-Los Angeles, is seeking to place on the June 2018 ballot.

The total includes $300 million for water and flood districts in the Central Valley to repair flood-control systems or build new ones. Another $100 million would go primarily to bolster Delta levees, with the remaining $100 million aimed at projects to prevent damage from stormwater and mudslides.

“There is a larger issue we can no longer ignore,” de León said in a statement. “Climate change is here, and it’s real. It is impacting our communities. It is costing our state billions in damage and severely affecting peoples’ lives. California needs to build greater resiliency into its water and flood systems.”