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.

[meyer]

Indeed they are. I wonder if those holes cut were for inspection purposes. Nothing like getting a visual of the situation to really assess. The Dam Cam shows that they’re drilling and placing explosives across the width of the spillway at the new level.

i wonder if the part they’re removing is going to include those sections in which additional anchors were added a couple of months ago...

[mad_as_he$$]

Geo related but no impact on the dam:

QUINCY, Calif. (KOLO)— A train derailed early Saturday near the California community of Virgilia about 100 miles northwest of Reno, the Plumas County Sheriff’s Office reported.

Fifteen cars of a 74-car BNSF Railway train derailed but were on the track and upright in the Feather River Canyon about 12 miles south of Keddie.

BNSF Railway said the line reopened earlier Sunday.

The derailment happened about 2 a.m. on Saturday. BNSF said the train carried all kinds of freight and there were no injuries and no hazardous materials compromised. The sheriff’s office found no hazards.

The railroad brought workers and equipment to fix the derailment. The sheriff’s office said there did not appear to be any foul play. BNSF said the cause of the derailment is under investigation.

[EarthResearcher333]

The current "cut" line on the upper spillway is well above where the rock bolts were located. I did see blast gear spread across on the ground in front of this "cut" line in the foundation material. This gear would be close to where the prior rock bolts were located.

[EarthResearcher333]

Revisiting the 100,000 cfs crisis flow Feb 15, 2017 - DWR likely had a "debris" problem - Kept Gates 7 & 8 closed - Created Whirlpool

Image reveals that on Feb 15, 2017 Gates 7 and 8 were not open during this mid-day 100,000 cfs flow. The induced asymmetrical flow caused a whirlpool to form at the gate inlets. Although the water level was at least 20+ feet above the radial gate top inlet, the breast wall inlet curvature could have facilitated a submerged log entering into a gate inlet. Log & wood debris is observed on the far side to where Gates 7 & 8 are located.

Dramatic turbulence formed upstream from this asymmetrical flow. The formation of the whirlpool also posed a threat in its ability to draw debris downward into an inlet should the floating debris migrate towards the whirlpool.

Debris "strikes" on the metal skin plates of the Radial Trunnion Gates are considered "unusual or extreme loads" in the overall design load stresses. Vector arrows reveal the water "convergence fins" created by the concrete pier columns. Counting the "convergence fins" reveals how many chutes are open. It seems DWR chose to not operate 7 & 8 for a reason (assumed due to the debris concerns). However, the inlet turbulence and the whirlpool would have created elevated hydrodynamic forces on the Radial Trunnion Gates (i.e. non laminar flow conditions).

There is a history of Gate binding and sealing problems. More on this later.

[Ray76]

I’ve always been amazed that the design allows water to approach the gates at other than a normal angle.

[abb]

Perhaps hoping that keeping 7 & 8 closed would minimize damage to that side of the spillway?

[meyer]

You’re right - way above the rock bolts. It is sometimes deceptive when I look at it, especially when I look at the night-time “Dam-Cam” shots. With a long focal length lens, the relative distance appears a bit compressed.

I’m curious as to what their plans are for the bottom of the spillway - the “diffuser” (for lack of a better name) with the huge concrete blocks.

I noticed that to the left of the spillway, as viewed from the bottom across the river, they are assembling what appears to be a very large crane.

Dam Cam link -

http://www.parks.ca.gov/live/lakeorovillesra_spillway

[PavewayIV]

I can't locate the specific article(s) that quote him meyer, but I recall Croyle saying on several occasions that the existing baffle sill section (w/diffuser blocks) was to remain in place. The surface damage on the concrete baffles will be repaired. you can see the demolition of the lower spillway has proceeded right up to the sill section.

Of course, nobody in the press or audience thought to ask him why, exactly, they were preserving that particular piece of beat-up, half-century old design. We all know the answer though: because it hasn't failed yet. DWR's acid test for public safety and responsible engineering is: "Has it failed yet? No? Then it's safe and nobody can prove otherwise."

I've read criticism from engineers that this isn't a terribly good design. Fire-hosing water at 100 fps down a steep spillway and then using energy-diffusers at the bottom is kind of third-world-ish and far from 'modern practice'. In fact, it's a recipe for disaster in the future.

In addition (but apparently more questionable/controversial) is the diffuser/stilling pool emptying at right angles to the diversion pool. The problem is water backing up into the dam outlets as we saw this winter. Some of the energy from the spillway could be used to increase flow out of the upstream diversion pool and potentially flush silt or erosion debris further downstream. Some argue this shouldn't ever be necessary, and others say the potential for scouring and erosion outweigh the potential benefits. Seems like a useful idea to me since the emergency spillway is going to remain mostly unarmored. Disclaimer: I haven't designed any dams since fifth grade.

Nobody (that I've read/found) has a good technical reason for why DWR is insisting on the historic engineering approach besides old-fashioned cheapness. It's 'good enough'. Comparisons have been made with the new Folsom spillway were effort has gone into slowing the flow as much as possible. They use a stepped spillway design there for that purpose. The design is inherently safer because you're not introducing a massive amount of energy into the flow, dealing with that hydrodynamic hell for a thousand feet or so and then having to dissipate it at the sill.

Slowing the flow means higher side walls. Oroville has 20' training walls (new Folsom has 30' ones). Croyle has always been oddly insistent about the training walls being adequate even though nobody has ever really pressed him on this issue. That always seemed strange to me - why call that out if nobody is even questioning it? That (to me) says there is some reason DWR is trying avoid even the suggestion that they might need higher walls. A more modern stepped spillway would require them, AFIK.

Higher training walls need significant anchorage beyond simply being bonded to the chute floor. DWR is either unwilling to pay for that and/or cannot physically provide that because of the fractured rock underlying the walls. One engineer was describing something similar to the secant pilings they need to use for the e-spillway cutoff wall. 3000' of pilings on both the spillway would be pretty expensive, so the existing firehose/mass/dissipator scheme with 20' training walls was dusted off, with more mass and anchorage added in.

Plus, seam cavitation ensures eternal work for local concrete contractors because every dam person seems to know they NEVER work anywhere on earth. It's always temporary and cosmetic. And besides, what's the worst that can possibly happen - seam erosion, seal failure, underslab erosion and hydrodynamic pumping? Why, that's preposterous! That's never happened anywhere EVER. Damn conspiracy theorists!

[meyer]

Well, to be fair, the baffle sill section of the spillway has probably seen the least amount of water of the entire structure.

But seriously, is it something they intend to replace next year? I don’t see it as having been ruined but if there’s a better way to deal with the water, then they should go for it.

[Repeal The 17th]

It should be dry or nearly dry behind the gates now...
http://cdec.water.ca.gov/cgi-progs/queryF?s=ORO&d=12-Jun-2017+19:26&span=24hours

[abb]

They have a pump going placing a slurry into Moonbeam Canyon. Perhaps that’s their solution to establishing a relatively level surface upon which the RCC ‘fill’ can be placed.

That is a big crane. It’ll be interesting to see what its used for.

[PavewayIV]

"...Well, to be fair, the baffle sill section of the spillway has probably seen the least amount of water of the entire structure..."

I don't disagree, but delaminating and scouring a concrete monolith like that down to the rebar is... troubling. This part of the spillway has probably seen the most amount of concrete missile damage. And a half meter or so of cavitation damage - enough to tear rebar out of the deck right at the sill - also seems to warrant more than a patch. Maybe they're worried about the time it would take for such massive blocks of structural concrete to strengthen before Nov. 1st if they rebuilt. I really don't know.

"...But seriously, is it something they intend to replace next year?..."

As far as I understand Croyle's statements, no. They intend to patch it up as part of the lower spillway rebuild this year. That's it. They never mentioned anything about deferring demolition and replacement until next year - I don't think that's their intention. Maybe I missed something.

[meyer]

I was being somewhat sarcastic with my “least amount of water” comment. But I do not think it’s a good idea to keep the structure in service. While it might only have modest damage topside, there’s no telling what’s occurred underneath. It is as old as the rest of the spillway structure, and unless they have compelling evidence that it’s a superior structure on bedrock (good bedrock), keeping it is only asking for future trouble. IMHO.

[The Westerner]

Thanks. So due to the spillway repair, California's Central Valley and SoCal is losing 30% of the water flowing through the Feather. I wonder what that translates to in water rates? It's sad after year after year of stringent water usage for the citizens of Ca. Perhaps if someone highlighted the magnitude of lost reservoir water, the citizens would demand a Special Counsel?

[KC Burke]

The Oroville Lake water simply takes a detour on the way to the delta and the sea. It goes to residents always with some amounts keeping the norther central valley agriculture going. It always goes to the sea — enventually, as the song says.

The problem is not that the lake isn’t being kept at full capacity, which shouldn’t matter is that it is one of a dwindling few lakes and even with no lakes built and no maintenance sufficient, the residents are even now paying 500 buck a month to fund (a) water studies intent of destroying lakes, (b) large bureaucracies with drought versus mankind thinking, (c) studies on building more reservoirs that really are (wink-wink) meant to keep them from being built.

If they committed to build the double capacity needed with seismic problems and the impact on everyone it would turn 500 dollar water bills into 800 or 1000 dollar water bills.

California is largely an arid country. The intensive agriculture (only part working even now) and the large urbanization far from water create a problem even without the political disaster that is leftist politics.

[PavewayIV]

"...keeping it is only asking for future trouble. IMHO..."

There are plenty of engineers on the internet that seem to share your view. This will eventually be a billion-dollar project (Folsom spillway/gates was $900M). Nobody expects this to be anywhere near the $400M (and certainly not the fantastical $250M) pricetag dangled in front of the public so far. How much money are they actually saving by skipping the baffle sill relative to the total real cost of this project?

If nothing else, patching up a broken piece of the 'old' spillway will serve as a very visible monument to the DWR's strange sense of economy. "We're too cheap to do the whole job. Just enough is good enough!"

Is it absolutely necessary to replace it now? Does it pose any risk? Is it important relative to everything else? I don't know, but NOBODY is going to complain if they just do it now when they have everything there. When you force 180K people evacuate their homes, then optics become rather important. 'Patching' seems like something you want to avoid if nothing else but for appearances sake.

If they were more transparent and gave the engineering community enough information to understand their reasoning, then maybe they would agree it's unnecessary or inadvisable right now. Nobody needs to convince me of anything, but I'm worried when I see people in the industry skeptical of DWR's actions over and over again. There's plenty of reasonable speculation as to why they're doing one thing or another, but never any confirmation either way - nobody really knows and DWR isn't saying.

DWR simply cannot play the "Just Trust Us" card to a skeptical public and/or engineering community, yet they repeatedly (and quite smugly) toss that one out over and over again. I can only shake my head and wonder what the hell they are really thinking most of the time.

[EarthResearcher333]

"Fire-hosing water at 100 fps down a steep spillway and then using energy-diffusers at the bottom is kind of third-world-ish and far from 'modern practice'. In fact, it's a recipe for disaster in the future."

Hi PavewayIV, you should look at the extensive analysis & testing done in the HYD-510 Hydraulics model testing for the invert chute blocks. There was a significant amount of testing and analytical work done in this design. I wouldn't dismiss this as "has it failed yet" type of a perspective. I give great credit to the engineers on this one aspect of the design.

In the many variations of validation testing there were an impressive array of micro piezometer tubings placed in a number of block locations to calibrate the hydrodynamic gradient along all of the surfaces. Shape tuning identified the necessary angles for the optimal performance. Yes they seem bulky, but they perform well for their design. Water is intended to create a "back pressure ramp" in the faces of the block backsides. There is even a small concrete protrusion at the inner chute block's lower corner, near the invert slab, to force a small corner aeration. That goes to show how detailed the work was done on this architecture.

Because the spillway is at a right angle to the Feather River, the extreme flow energy required a singular & powerful action to use this energy to transform it into an upward jump. This upward jump accomplishes two important functions. One, to prevent the far side river bank from experiencing severe hydraulic turbulent erosive forces, and the other is to prevent depth plunging of turbulent hydraulics into the river itself. IN the process of creating this "jump" the water flow is transformed into a highly aerated condition.

One option investigated was a "crash wall" on the far side of the Feather River from a simpler flip bucket. However, there are complexities that are created from this approach - besides another large construction addition to the project.

Folsom doesn't have to deal with the right angle dissipation into the Feather River. It is easier to have a section of energy dissipators, although Folsom will have some wear & tear that will need attention over time in the dissipators. Folsom also has the benefit of a higher exit velocity than Oroville and the right angle Feather River. A bit of apples and oranges.

In Oroville's new spillway, there are modern techniques of using aerators to create aeration within the higher speed flow of the spillway angle. This new technique reduces the atmospheric to hydraulic density changes that cause cavitation erosion. The BOC recommended incorporation of these devices in the new steep section of the lower spillway.

In Fact, the aeration of the Radial Gate Headworks Pier Columns has been a great benefit for the main spillway as the "convergence fins" of flow are large aeration devices. The injection of the air bubbles in the flow has benefitted the spillway even through the length of the steep section. (pre-injected air bubbles form miniature "shock absorbers" to any transition of pressure differentials in flow).

Adding modern aeration devices in the new main spillway will further reduce the minor surface imperfections on the chute dissipator blocks.

NOTE: These "aerator" injection devices (air slots) successfully eliminated a massive cavitation erosion problem in a spillway tunnel (Glen Canyon dam) - subnote: the origin of the cavitation problem was a tunnel design that was altered from its original design which created a second curve "jump" thus causing the severe cavitation.

As for the structural integrity of the chute blocks.. there are ways of verifying the integrity. Modern concrete repair technologies should be able to address the damage of the chute blocks and the lower concrete lip areas.

(keep in mind that these chute blocks were structurally designed for a max flow of 296,000 cfs.)

[EarthResearcher333]

Folsom Auxiliary Spillway "stepped dissipator" area - dumps energy reduced turbulent output flow into an existing rock faced discharge channel. This rock faced channel designed for turbulent flows from the original main dam discharges. Oroville's main spillway is at a right angle to the Feather River and must effectively transform the flow energy into an absorbable state while minimizing "plunge erosion" in the center of the river and also minimizing the far bank hydraulic erosion. Prior design testings had a "crash wall" and another design with a "curve redirection wall". The exit to the spillway was a simple upward curved "flip bucket" into these far river wall absorbers.

The final design ended up with a "flip bucket" upward launch of the flow with a simultaneous maximum aeration of the spillway water flow. This design retained the laminar flow in the 178ft wide invert chute until the flow reached the chute blocks. The height of the Oroville chute blocks are 23 ft with an anchorage depth of concrete to near 20 feet thick. Thus the greatest thickness dimension is close to 40ft from the top of the chute block to the lowest anchorage depth in solid concrete anchored to the rock - by a cut anchor notch in the bedrock of 15 feet deep x 50 ft slope x 178+ ft wide.

Folsom's new auxiliary spillway has the advantage of "slowing down" the flow through stepped dissipators as the turbulent exit flow enters an existing rock faced flow channel designed for the original dam spillway. Oroville's spillway has a hard energy stop challenge into the 90 degree Feather River orientation.

[EarthResearcher333]

FERC is deleting documents !!!

FYI - FERC IS RETROACTIVELY DELETING FERC/DWR COMMUNICATIONS DOCUMENTS/REPORTS ON THE OFFICIAL FERC PUBLIC DATABASE. The documents that have found to be deleted are critical reference doc's on the Catholic Online articles that reference the Anchor Tendons (reports & communications between FERC/DWR).

The doc's just disappeared - no CEII status change, nothing. They no longer exist on the database. HERE ARE AT LEAST THREE OF THE DOCUMENTS DELETED:

20000509-0242(986809) Prelim Anchor Tendon Ultrasonic testing report noting "no significant defects were noted" (this is a direct contradiction in what DWR is stating to FERC in crack defect findings verses the actual Ultrasonic testing results in 20000419-0130 -i.e. falsehood told to FERC)

20000419-0130(977645) Anchor Tendon Ultrasonic testing report with crack identifications report

19990322-0490(533695) Anchor tendon LLNL Ultrasonic vs high power ultrasonic testing discussion communications

[abb]

Did you save them on your computer when you posted them?