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Emergency: California’s Oroville Dam Spillway Near Failure, Evacuations Ordered
Breitbart ^ | Feb 12, 2017 | Joel B. Pollak1

Posted on 02/12/2017 4:26:47 PM PST by janetjanet998

Edited on 02/12/2017 9:33:58 PM PST by Admin Moderator. [history]

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.


TOPICS: Breaking News; News/Current Events; US: California
KEYWORDS: butte; california; dam; dwr; evacuation; lakeoroville; liveoroville; moonbeamcanyon; moonbeammadness; oroville; orovilledam; orovillelive; runaway; spillway; sutter; water; yuba
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To: EarthResearcher333

You know in the end the fix will be to just cover everything in a thick layer of concrete and re-bar.


2,661 posted on 03/24/2017 6:07:56 PM PDT by Rebelbase
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To: janetjanet998; All

The latest from Juan, BVB

https://www.youtube.com/watch?v=4gnOziaifIY


2,662 posted on 03/24/2017 6:44:33 PM PDT by Bobsvainbabblings
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To: janetjanet998; All

The latest from Juan, BVB

https://www.youtube.com/watch?v=4gnOziaifIY


2,663 posted on 03/24/2017 6:44:33 PM PDT by Bobsvainbabblings
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To: Bobsvainbabblings

Thanks.
Sounds like Juan is catching up on some of the things
we have been discussing here in the last few days.
One thing I heard new was the “Cyclopian Wall” plan.


2,664 posted on 03/24/2017 7:34:18 PM PDT by Repeal The 17th (I was conceived in liberty, how about you?)
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An engineering expert who visited the troubled Oroville Reservoir said this week that it would be nearly impossible for the state to complete temporary repairs to its fractured and eroded main spillway by a target date of Nov. 1.

In a report submitted to the Federal Energy Regulatory Commission this week, a panel of five independent consulting engineers warned that “a significant risk would be incurred” if the main spillway was not operational after October, which is the traditional start of California’s rainy season.

However, an engineering and risk management expert who was not part of the consulting panel told The Times this week that he doubted the state could meet such a close deadline.

“I think that is a challenging timeline,” said Robert Bea of UC Berkeley’s Center for Catastrophic Risk Management.

Bea, a retired civil engineering professor who led an investigation into failure of the New Orleans levee system after Hurricane Katrina, visited the reservoir recently to review inspection documents, as well as the report by the Independent Board of Consultants.

The consultants proposed that temporary repairs to the spillway be completed by Nov. 1, and that permanent repairs be completed after the rainy season.

In order to accomplish this, report authors said the Department of Water Resources should award grading contracts by March 31, complete design plans by mid-May and approve a construction contract by June 1. That would give the company five months to complete the work, the report suggested.

Bea said that schedule leaves little space for unanticipated problems.

http://www.latimes.com/local/lanow/la-me-ln-oroville-repair-timeline20170324-story.html


2,665 posted on 03/24/2017 9:06:42 PM PDT by Ray76 (DRAIN THE SWAMP)
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To: Repeal The 17th

I don’t know if a link to this doc has been posted yet, but it mentions “cyclopean check dams”

https://www.ferc.gov/industries/hydropower/safety/projects/oroville/03-17-17.pdf


2,666 posted on 03/24/2017 9:13:20 PM PDT by Ray76 (DRAIN THE SWAMP)
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To: Ray76

Thanks!
-
“Additional aspects of the short-term mitigation consist of the cyclopean backfill
placed downstream of the approximately 1,000-ft-long monolithic ogee weir section.
The weakest point in this plan occurs at the downstream end of the armoring where
all flows are directed and become channelized. To this end, DWR has placed small,
3-ft-high cyclopean check dams to slow the flow in these areas and control the
gradient. The knickpoints in these channels downstream of the check dams could be
problematic should future flows occur.
-
9
[This displays as page 5 of 16; the physical page number is 3]


2,667 posted on 03/24/2017 9:20:39 PM PDT by Repeal The 17th (I was conceived in liberty, how about you?)
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To: Repeal The 17th

[a knickpoint is part of a river or channel where there is
a sharp change in channel slope, such as a waterfall]


2,668 posted on 03/24/2017 9:25:45 PM PDT by Repeal The 17th (I was conceived in liberty, how about you?)
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2,669 posted on 03/24/2017 9:48:06 PM PDT by Ray76 (DRAIN THE SWAMP)
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To: Ray76
Googling up images for cyclopean you see things like this:

But it sounds like they are actually talking about
the boulders that they are embedding in shot-crete.
2,670 posted on 03/24/2017 9:49:20 PM PDT by Repeal The 17th (I was conceived in liberty, how about you?)
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To: Ray76

Whoever came up with the idea for a ramp so the flow could
jump across the gap should never be allowed to speak again.


2,671 posted on 03/24/2017 9:52:04 PM PDT by Repeal The 17th (I was conceived in liberty, how about you?)
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To: Repeal The 17th

If they just want to keep the water away from the break and avoid any undercutting erosion sure, but jumping the gap.... The impact of the uncontrolled water on the other side, the splashing.... yeah, it’s crazy! Chaos.


2,672 posted on 03/24/2017 9:59:44 PM PDT by Ray76 (DRAIN THE SWAMP)
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To: Repeal The 17th
As long as this guy isn't involved


2,673 posted on 03/24/2017 10:05:27 PM PDT by Ray76 (DRAIN THE SWAMP)
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To: Ray76

I’m pretty sure cyclops works for the State of California in some role...


2,674 posted on 03/24/2017 10:11:05 PM PDT by Repeal The 17th (I was conceived in liberty, how about you?)
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To: abb; Grampa Dave; Jim 0216; WildHighlander57; meyer; Repeal The 17th; KC Burke; Oldexpat; ...
DWR's 1960's Split spillway "engineering political solution" coming back to haunt the future? (new Failure mode of the entire dam)

Its looking like an "engineering political solution" is coming back to haunt the future. In the 1960's, rather than make the Original combined spillway design of 620,000 cfs work, the intervention of DWR's decision to split the combined spillway into two separate designs has forced a "lock-in" of the new "fixes" (see post link below). Yet another seeming "engineering political solution", possibly related to an expensive price tag, has the consequence of catastrophic destruction of a hillside triggering a "chain of events". This "chain of events" could lead to a swirling back flow that could erode the "toe" of the main dam, thus risking a failure collapse of the whole dam itself. This "failure mode" has been identified by a world renowned leading dam expert Scott Cahill. Scott identifies a dangerous erosion scenario that could cause the "loss of the Oroville dam" (via "eddy swirls" at the toe of the main dam).

The New "Board of Consultants (BOC)", of advising experts to DWR, has stated a requirement of restoration of the rated 646,000 cfs flood capacity of the combined spillway flows (see March 10, 2017 report below). HOWEVER, the new "upped" rating of a huge 396,000 cfs requirement of a new Emergency Spillway includes the caveat: "damage below the Emergency Spillway to be expected". This directly implies that there will be erosive damage. Given the known geology and the actual alarming erosion of "rotten rock" & debris from the last Emergency Spillway incident, the only method to prevent a repeat of this is to armor the hillside all of the way to the Feather River.

We will see how this "damage to be expected" is translated into a new design. Is the "damage" limited to the "armoring itself" or is it damage to an unconsolidated hillside further below an "armoring apron" (or both)? The latter is what could engender a very problematic sequence. (1) If the max rated 396,000 cfs destroys the hillside, a "dam" would form in the Feather River channel. (2) The main spillway chute is upstream, thus flows from the main spillway likely would "backflow" towards the "toe" of the earthen dam. (3) This backflow would form an "eddy swirl" at the "toe" terminus. (4) dangerous destabilizing erosion of the backside toe of the earthen dam would occur. (5) to prevent this "eddy swirl" or partially limit its intensity, the main spillway would need to be slowed or shut off. (6) Further erosion would occur from the Emergency Spillway handling "flood control". This is an inverse repeat of what is currently going on at the dam - BUT- with the exception of a lesser eddy back flow towards the dam (has since been mitigated by the excavation of most of the 1.7 million cubic yards of rock/debris.

The only clean design that "preserves the safety of redundancy" is by fully armoring the Emergency Spillway for the full length of the hillside to the Feather River. But the associated costs for this may become a difficult "political" funding issue.

The 1960's DWR decision is still front and center today

1960's DWR steps in and makes a "command decision" (i.e. "political engineering") when faced with a design crisis challenge creating a *failure* compromise

Expert panel of "Board of Consultants" requiring new Emergency Spillway to handle an upward revised 396,000 cfs down the hillside. "Damage Below the Emergency Spillway To Be Expected".



2,675 posted on 03/25/2017 6:36:13 AM PDT by EarthResearcher333
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I finally got a few free hours this week, due to rainy, windy weather oddly enough, to revisit a large amount of material on FR and a couple of other sites. Brought up many images on the jumbotron at work. Some are surprisingly detailed. I have concluded the following:

1. All of the remaining spillway is damaged or undermined beyond repair. There is just too much bad construction and damage to be sure that a patch job will not fail in the future.

2. I am very concerned about the main spillway gate structure. There is some limited information that it is weeping more than expected or designed to.

3. The e spill is a joke and needs to be seriously evaluated and dealt with.

I think the prudent course of action is the construct a new spillway - including a gate structure - adjacent to the existing one using modern techniques and design. This would allow the project to go through another wet cycle using the damaged system, in the meantime, if needed. Caisson pier system and pressure grouting the “bedrock” down to a 100 feet of so would stabilize the area significantly. Modern rebar specifications and concrete technology. They are not going to catch any breaks on this situation. The geology and past sins are an too big of a hill to climb

2,676 posted on 03/25/2017 6:58:14 AM PDT by mad_as_he$$ (Rick Grimes Rules.)
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To: EarthResearcher333

From the article :

“8. “The panel report also said that while touring the spillway, consultants spotted “extraordinarily large” amounts of water gushing out of drains designed to move water out from beneath the intact portion of the chute. The water was flowing even though the spillway’s gates were closed and it wasn’t raining,..””

Now, where would that water be coming from?

From under that rectangular object right behind the main spillway gates?


2,677 posted on 03/25/2017 7:25:52 AM PDT by WildHighlander57 ((WildHighlander57, returning after lurking since 2000)
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To: WildHighlander57
“The panel report also said that while touring the spillway, consultants spotted “extraordinarily large” amounts of water gushing out of drains designed to move water out from beneath the intact portion of the chute. The water was flowing even though the spillway’s gates were closed and it wasn’t raining,..”

Hi WildHighlander57, You ask a great question - this reveals a Sac Bee reporter's "editing liberty" on the BOC report (..where would that water be coming from?).

The Sac Bee reporter edited wording from the BOC report which changes the context of what the inspectors actually observed. Without looking at the actual Board of Consultants report, the Sac Bee reporter's writing could let a reader think that "gushing" water was flowing all of the time - even when the gates were closed and it wasn't raining. Wrong. If you read the actual BOC report wording, the "gushing water" from the herringbone structure spillway underdrains is when the spillway is in operation. (i.e. NOT "gushing" when the spillway is shut down.). The BOC correctly concludes the origin of this "gushing" water as from cracks in the slabs and from seams in the slabs that are "collected" by the drains.

Another very important point the BOC identifies is that water is coming back "up" through cracks and spalls in the slab when a light flow is present along the sandbagged rerouted side of the spillway. This means that there is a "channel" that the water can flow under the drains (i.e. not collected by the drains) and resurface further down the spillway. They also note, very importantly, that "piping" is part of the process. This is the same as water "channeling" through paths under the spillway & is a "wash erosion" issue - thus the statement of "..seems likely that piping of foundation material beneath the chute slab may be responsible for the voids that have been found and repaired in the past." Bingo!! The spillway was emplaced upon erodable material - see post link below.

Now the most interesting part is the BOC statement: "The drains appear to flow for some appreciable time after the gates are closed and not precipitation is occurring".

For this condition to occur there has to be either a "pooling" of water in an elevation just above the spillway undersurface, or, a pressurized form of a rebound spring of subsurface water from below. I suspect it is the former. In this case, water could be penetrating out of the sidewalls into the backfill areas & chute hillside. It then would re-flow back towards the lowest point where the sub drains are located. ANY water that escapes outside of the chute area has foundation consequences over time. "Fines" of small material could migrate from the backfill areas and chute hillside, forming voids, pockets of water, and potential alternate "piping" routes outside of the chute. Not surprising that the BOC stated "The BOC believes this situation should be investigated".

Subsurface Seam at Blowout Failure location. Photograph provides insight into how "un-captured" waterflow in the sub-par drain design could "wash" a void layer between the bedrock and the concrete slab pour



2,678 posted on 03/25/2017 8:34:07 AM PDT by EarthResearcher333
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To: mad_as_he$$; EarthResearcher333
construct a new spillway

That thought keeps running through my head.

2,679 posted on 03/25/2017 10:25:49 AM PDT by Jim W N
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To: Jim 0216

My head too. New spillway, next o the damaged one. Then, maybe, a complete replacement of the damaged one so that it can serve as an emergency spillway instead of the present system of overtopping a wier.


2,680 posted on 03/25/2017 11:43:17 AM PDT by meyer (The Constitution says what it says, and it doesn't say what it doesn't say.)
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