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

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

[Ray76]

Gray rock building up in the river again too.

[meyer]

Good video. Yeah, there is plenty of debris at the bottom again, but nothing like it was. Still, seeing gray rock is not as positive as it could be, but given the enormous turbulence that takes place as the water tumbles down the ravine, I would expect that it would break off a lot of the looser stuff that is jutting out.

The part of the video at around 4:45 illustrates why I thought that they would build out a hardened ramp from the base of the break-off point sloping downward into the plunge pool. That would allow them to throttle back lower than 40,000 cfs and still not scour up the looser dirt/rock.

If they could find a way to get a steady 10,000-15,000 flow (plus the 11-14000 from the plant) out of the reservoir without using the spillway, that would be great.

[WildHighlander57]

janetjanet998 wrote:

“video of the shutoff yesterday

https://www.youtube.com/watch?v=ixTg5Tgzeus

dark discolored area coming from the rock bolts”

At what timestamp did you see the dark discolored area?

[Ray76]

Every component of the complex has issues.

The spillways have design/construction issues. The main spillway has operational/maintenance issues.

The dam has operational/maintenance issues at the wet area.

How did water/debris enter the powerhouse? Is there a design deficiency? Or an operational problem?

[meyer]

The water/debris in the power house is a direct result of the tailwater (bottom of the dam) rising up a great deal during the initial spilling. They scoured out a LOT of earth on that run, especially when they ran at 100,000 cfs in panic-mode (reality-induced panic, I might add). I don’t remember how high the tailwater rose, but it dropped 25 feet or more within a few hours of shutting off the spillway the first time.

There’s a lot there that needs attention, if not fixing. The most obvious issue right now is the main spillway. For now.

[Ray76]

That seems like a design and an operational fault. Apparently there is no gate or valve to prevent tailwater entering the powerhouse, which is a design issue. Once the situation was developing nothing was timely deployed to prevent tailwater entering the powerhouse, which is an operational issue.

There seems to be a culture of complacency.

[meyer]

I would lay that on the spillway. They didn’t design to have the river clogged up with almost 2 million cubic yards of debris that was washed down the hillside as the spillway waters cut their own ravine. That’s what backed things up. IMHO.

The power plant was designed to operate in concert with the rest of the complex, which was also expected to operate properly.

I would think that a main shutoff valve of some sort on the tailrace would be useful here (they might have one already, I don’t know).

[Jim W N]

The most obvious issue right now is the main spillway. For now.

After seeing the issues with the dam itself, maybe they need to first lower the reservoir water level to 660ft so at some point sooner than later they can begin corrective action there as well.

A lot of stuff.

[Jim W N]

The Oroville Dam is starting to look like an emergency room triage.

[Jim W N]

The Oroville Dam is starting to look like an emergency room triage.

[Ray76]

That’s true.

Conversely, it was expected that the emergency spillway would be used. Then again, the ES seems like it was a box to be checked off.

[meyer]

The Emergency spillway - a contingency plan that wasn’t ever expected to be used. And for good reason, which was proven when it was used.

[abb]

Judging from that video of the shutdown, the shotcrete treatment at the face of the spillway break didn’t hold up too well.

See what y’all think.

https://www.youtube.com/watch?v=3Tcf9jXoS6Q

[meyer]

I don’t think they used the shotcrete to build a water ramp so much as they reinforced under the bottom of the spillway to prevent further collapse. The brown muddy water is a result of lowering the spillway enough that it was no longer throwing the water out over the softer material to the grey bedrock.

I had hoped that they would have built a hardened ramp there but they didn’t.

[EarthResearcher333]

"My question would be, is it seeping through the dam or is it seeping in from the side via surface soil material."

Wet Area Analysis (discussion): I've scanned through all of the reservoir water elevation levels & compared the available photographs from (1) Inspection report dates (2) sat image dates (3) other images w/ dates. There is no 1:1 direct answer to cause-effect (of "green vegetation) from just this matrix. However, if you add in a precipitation factor, it does imply a component that facilitates the "greening". One data point on this is the "drought conditions" of 2016 where the precipitation factor was low.

However, since evaporation becomes prominent in very dry conditions (in the embankment), it doesn't answer the question adequately, other than give an indication to the weepage flow volume.

Yes, there is the theoretical possibility that an underground embankment source near the abutting canyon side wall seam may be injecting water into the embankment. The horizontal "seam" nature of the wetspot is the puzzle in this case. You would expect a dispersion pattern downhill (upside down "V") instead of a horizontal embankment origin.

The Palermo tunnel (4:00 position in black circle of 1st photo) has visible waterflow that empties into the Palermo canal. But this tunnel is at an elevation in the side bedrock of the canyon wall that is 99ft lower than the elevation of the "wet area".

This whole question gets back to: With Dam Inspectors stating that this issue should be "investigated" and "action taken" to protect the embankment (depending on findings), why hasn't this been done? (the 2016 Inspection report only states that it had dried up - no answers as to the "remedial repairs" that have fixed the problem).

Investigating this (i.e. "easy test") requires (1) recognition that this is a priority issue (2) procure funding to investigate (within a budget or otherwise) (3) perform the investigation. There is no easy test. Besides, why do Dam Safety Inspections with recommendations/actions if (1)(2)(3) are not followed up upon?

[Repeal The 17th]

This is the first I can recall hearing about the Palermo tunnel/canal.
Is that yet another way to get water out of Oroville Lake?

[EarthResearcher333]

"This is the first I can recall hearing about the Palermo tunnel/canal. Is that yet another way to get water out of Oroville Lake?"

This canal predates the dam. The Palermo canal was originally constructed to facilitate a water source for gold mining. It looks now to run through areas that have agricultural uses. It is more of a stream flow than any type of a release source for the dam. Since the Dam would have cut off this supply, a 6ft avg dia tunnel was constructed in the side dam bedrock to re-connect it to on the other side of the dam.

Zoom in on the picture - you can see the white water ripples in the stream flow.

[mad_as_he$$]

No surprise here, as expected and predicted. Waste of time energy and material. But hey we did something!

[Jim W N]

No surprise here, as expected and predicted. Waste of time energy and material.

With Moonbeam in charge, any dog-and-pony show is possible which is exactly what that looked like to me. Clearing the river was reasonable, but this other stuff? I'm not an engineer and even I could tell that all this shotcrete wouldn't amount to a hill of beans, pun accidentally intended.

Wonder how much money was wasted on this, not that the government cares. It's not their money, it's everybody else's money.

[EarthResearcher333]

Water Seepage Issue - Answer from "layered" construction of earthen dam? - (problematic "Wet Area" aligns at seam of Layer 2 & 3)

More Clues: The Logistics of moving the fill material conveyor system drove a "layered" construction approach to the main Oroville Dam. At the top of each layer the surface was smooth as observable in early construction photographs. In typical construction, the surfaces would be slightly crested to prevent "pooling" of rainfall. Evidence of this is revealed in the "seam" elevation curve measurements on the outside of the dam. With a slightly sloped crest, and a smooth type of surface to each large step "layer", a moisturized surface exposure (natural rainfall) could occur as one layer is finished before the next layer is started. These factors may explain the unusual horizontal nature of the problematic water seepage. The problem area is right near the seam of the junction sections of the top of Layer 2 and the bottom of Layer 3. The same "layering" may also apply to the impervious core emplacement (stages).

The water issue reveals itself in a recent March 15, 2017 aerial photograph. Very strong greening in horizontal sections reveals a water source. The water source and "greening" also reveals a "sheet" type of dispersal - which would conform to the layer seam formed in the construction of the dam. With the elevation arc cresting of the layers, the inferred source to the water is from the boundary of layer 2 top and layer 3 bottom. The 2017 image reveals that there is little to no greening to the other areas of the dam embankment surface. If precipitation were the source to this "wet area" vegetation, there would be an expectation of other green areas (is little to none).

Oroville Earthen Dam built in sectioned layers - construction image reveal a "smoothing" at a layer elevation point (Layer 1). May form a "seam" from the smoothing. Conveyor system noted in the image.

Layer 1 and Layer 2 revealed in model. Oroville Earthen Dam built in sectioned layers - model infers a planned "smoothing" at a layer elevation point. A type of "seam" may form via the smoothing. Model shows the construction approach to the logistics of relocating a progressive earth fill conveyor system.

Layer 1, Layer 2, Layer 3 revealed in model. Oroville Earthen Dam built in sectioned layers - model infers a planned "smoothing" at a layer elevation point. A type of "seam" may form via the smoothing. Model shows the construction approach to the logistics of relocating a progressive earth fill conveyor system.

Wet Spot returns: visible in 2017 - Notable green vegetation growth in horizontal strips - near seam of Layer 2 top and Layer 3 bottom seam boundary. Picture taken March 15, 2017