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.

[KC Burke]

Hopefully, they’ll make a good decision rather than a political one.

ROTFLMAO -- I will remind you that you said such a thing.

[meyer]

LOL - I guess it wasn’t my brightest statement.

Side niote - they apparently have brought on a second generator. CFS doubled this hour.

[EarthResearcher333]

Crews using Ground Penetrating Radar on Main Spillway - Looking for voids, unseen cracks, erosion…Plus sealing joints.. DWR & experts know the enemy to the Upper Main Spillway. They are very, very carefully mapping every foot of area using Ground Penetrating Radar. The enemy of further damage is to assess the hidden structural slab risks, such as the dangerous & powerful effect of Stagnation Pressure (i.e. "hydraulic jacking" of the slabs).

Engineers also should be very well aware of the actual construction by now - given the exposed evidence of the broken spillway. IT makes perfect sense to take these measures.

What they are doing now is correct & is the right action(s) to take. I believe they will address any subsurface risk with possible coring to emplace sub void fixing materials if needed.

comment only: However, whomever was in charge years prior, they should have been doing this exact same work to prevent the main spillway failure. They had the warning sign/alarms (excessive water in drains, missing water, & crack patterns).

Crews using Ground Penetrating Radar on Main Spillway - Looking for voids, unseen cracks, erosion…Plus sealing joints.. note the red marks carefully delineating each run (x & y).

Engineers discussing a long crack in the Upper Main Spillway (note this angle of crack is the "herringbone" pattern angle that has followed underslab drain pipe placement). Note their tilt from the spillway angle.

[abb]

Had a visit last night with our city’s sewer/water engineer at the monthly council meeting. Asked him about VCP, and he said it’s not used in new construction very much, except New York.

Roots. He said they spend lots of time with “roto-rooters” cutting out root infiltration. Of course, down here in the south, vegetation is a bit more luxuriant.

To be fair, back in the 60s when the dam was built, VCP was state of the art.

[mad_as_he$$]

No big project in Kalifornia gets done for $200 million. This will be an $800 million deal before they are done with it. Might even crack a billion.

[meyer]

Question - what is VCP?

Info - they are using ground-penetrating radar to analyze the ground beneath the remaining portion of the spillway, if that hasn’t been noted already.

Also, they’ve been running 2 units at the Hyatt plant all night at around 3520 cfs. I think that they’ll analyze and bring on more as long as the flow in the river below looks good.

[meyer]

And had I looked a couple of posts above, it has already been noted that ground penetrating radar is being used. Sorry.

[meyer]

March 6 video from Juan Browne....

https://www.youtube.com/watch?v=5xa_Q1R7mGs

[meyer]

Re post 2273 - do you suppose that there might have been 2 clay pipes running through that section of slab, but that one has been broken away? That almost looks too perfect for the pipe to have moved during the pour and still retained the round shape.

[abb]

https://en.wikipedia.org/wiki/Vitrified_clay_pipe

Vitrified clay pipe (VCP) is pipe made from a blend of clay and shale that has been subjected to high temperature to achieve vitrification, a process which results in a hard, inert ceramic.

VCP is commonly used in gravity sewer collection mains because of its long life and resistance to almost all domestic and industrial sewage, particularly the sulfuric acid that is generated by hydrogen sulfide, a common component of sewage. Only hydrofluoric acid and highly concentrated caustic wastes are known to attack VCP. Such wastes would not be permitted to be discharged into a municipal sewage collection system without adequate pretreatment.

[abb]

[meyer]

Thanks. To us pikers, it’s just plain ol’ clay pipe.

[meyer]

Despite having 2 units on line, they’re creeping up on that important 860 foot mark. I hope that they get more generation going soon. It will buy time to finish getting the downward part of the spillway/erosion path groomed for service.

[abb]

Yup, glorified pottery. And almost as frangible.

[meyer]

Also attractive to Maple Tree roots, as we learned decades ago. :)

Maples, or at least silver maples, were known for aggressive root growth, and finding water if it leaked out between clay sections, would cause them to increase their root growth in that direction, resulting in having to dig up ones’ front lawn to replace said drain pipe.

The tree was cut down with vigor.

[EarthResearcher333]

"..do you suppose that there might have been 2 clay pipes running through that section of slab, but that one has been broken away? That almost looks too perfect for the pipe to have moved during the pour and still retained the round shape."

The cross-sectional area answers this.

(i.e. can't fit two adjacent pipes plus the gravel into this same cross-sectional [CS] volume).

The Polyethylene plastic sheet left a perfect forensic outline of the CS volume. What I suspect happened is that when the heavy concrete pour was vibrated, the plastic "tent" design deformed where the "marble like" round rock actually went under the drain pipe to the other side, forming the adjacent hump. That's how the plastic ended up wrapped around the one side of the drain pipe & no drain rock on that side - and most/all of the rock on the other side (an voila, the "hump").

This design is very unstable to overpour concrete & vibrate it - as you can see from the results.. I'm surprised someone didn't think of what would happen.

[meyer]

I was thinking more in terms of they laid down 2 pipes for whatever reason in that spot. Then poured. The concrete will, depending on viscosity, flow to fill around it regardless of the drawing. In other words, I was wondering if they deviated from the drawing to accommodate two pipes for some reason.

Keeping in mind that I’m a bit of a novice in this area. I can certainly see how the vibration/shaking process could dislodge things and leave voids where they once were.

[EarthResearcher333]

"I was thinking more in terms of they laid down 2 pipes for whatever reason in that spot. Then poured. The concrete will, depending on viscosity, flow to fill around it regardless of the drawing."

Let's puzzle this question….

Below is a reference image proposing a 2 pipe outline formation. Possibilities: 1. What if the mating pipe disconnected and shifted? (this "shifted" & "disconnected" pipe end mating section would have filled the circle area next to the existing pipe). Possibility 2. What if there were 2 pipes, side by side?

Possibility #1 - If accurate, the mating outline should have a curve arc left in the concrete void. But the concrete void has an irregular curve arc (realm of possibility that the end was fractured, leaving a non-smooth arc).

Possibility #2 - 2 complete pipe runs were placed adjacent to each other. Although this goes against the single run drain & longitudinal collection design, stranger things could have happened…. This case would mean that all of the surrounding drain rock must have existed in the blue outlined hatch line area (best estimate).

In order for #2 to match the image, the missing CS area of the rock would have to be puzzled out (also, an answer on how someone kept their job when the foreman saw this…2 pipes vs single pipe construction design). #1 becomes less of a possibility as the volume of the void extends deeper under the concrete. Thus the "disconnected" end would have had to have been shoved beyond the pipe mating intersection. The irregular arc also casts doubt on #1.

So far the best fit is a single drain with "pushed drain rock forming the adjacent hump". Why? Look to the "widening" of the plastic to the left. It is following the original pyramid or "tent" design, albeit irregular from concrete pour forces. Also, the combined volume of the blue outlined area plus the 2nd proposed drain pipe area best fits the total cross-section area of a symmetrical pyramid "tented" design for any original placed rock…… (side note: I find this photo very interesting as it looks like a natural break apart of the concrete slab. For the original drain rock to be present means there was no hard scouring of water after it broke - so where did this piece of evidence come from?).

[Repeal The 17th]

Hello, ER333,
...regarding the 6 inch vitrified clay pipe...
is that 6 inch ID or 6 inch OD?
Do all of the previous drawings and analysis
also take into account the size of the female end flange?
which can add another two inches to the diameter?
(I have laid a bit of this in a past life)
We could be talking about a total of 8 inches
or greater reduction in the thickness of the slab.
I do not understand the logic of making a permeable drain and
then deciding to cover it with an impermeable plastic wrap.
It just does not make sense to me.
I also do not understand why the drains were not located
directly under the slab joints (control joints)
where leakage would be most likely expected to occur.

[Repeal The 17th]

https://cdec.water.ca.gov/cgi-progs/queryF?ORO
The “Inflow” numbers look strange...
03/07/2017 13:00 14416
03/07/2017 14:00 13726
03/07/2017 15:00 10993
03/07/2017 16:00 3561
03/07/2017 17:00 9314
03/07/2017 18:00 15146