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Oroville Dam Spillway Leaking (Again, 18 March 2019) As Waters Rise (Again) Behind Dam 27

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racookpe1978

racookpe1978

Nuclear
Feb 1, 2007
5,968
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Complete failure at Oroville Dam
Original story and links at
| 3/18/2019 | by Chriss Street

Details at
Posted on 3/18/2019 at , 1:42:12 PM by rktman

From that story,
The $1.1 billion spent to repair Oroville Dam is failing as water is seeping through the rebuilt spillway threatens new mass evacuations over the risk of the dam collapsing.

According to national dam expert Scott Cahill of Watershed Services of Ohio, Oroville Dam is on the same failure track as in 2017, with visible water seepage trickling from the foot of the dam and dozens of points along the dam's principal spillway. Cahill warns that warming temperatures magnified by precipitation is a growing threat to the dam.

American Thinker reported on March 1 that the Sierra snow pack was at a record 113 inches, but another 44 inches fell in the next 10 days. With temperatures spiking this week to 75 degrees in the valleys and 41 degrees in the high mountains, dam inflows are running twice the outflows, and the water levels rose from 800 to 839 feet.
 
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"I posted no rants and made no mention of political bias myself."

No, you just posted a full-page screenshot of someone else proclaiming the site's political bias...not really any different in my book.
 
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Now if they had said 2.2 acre-feet per second...

"...it is not the result of water from the reservoir moving through the dam and does not indicate an erosion problem."

Regardless of that statement, and from working on past hydroelectric projects, I still have my doubts as to the validity of that statement, but time will tell. I find it hard to see a spillway fail due to a lack of support without erosion, and the watertable behind the dam is the biggest culprit, cutoff trench or not.

Mike McCann, PE, SE (WA)


 
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Here is a good size photo from mid January of water leaking from the spill gates.
Link

Here is a very large version of the photo from American Thinker.
Link
 
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HotRod10 said:
"I posted no rants and made no mention of political bias myself."

No, you just posted a full-page screenshot of someone else proclaiming the site's political bias...not really any different in my book.
Click to expand...

I edited my original post to remove the incendiary references to political bias from the image.
 
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And if you watch the latest Juan Browne video posted by EdStainless, you'll note that he explained that the spillway gates were never designed to be watertight and therefore now that the level of the reservoir has reached the point that it has, that some leakage of water down the new spillway was to be expected and should not be seen as a problem or a portend of things to come.

Besides, who's to say that those photos weren't take after some local rainfall. After all, California has been enjoying a very nice and wet winter and officially there is not a single country in the state which is considered to be under drought conditions, something that hasn't occurred in over 10 years.

John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without
 
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Wow, just stop. There simply is no moral high ground left for you to take after posting a link to that Palmer Report site.
 
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Hutz; If you're going to say that you should also include the original post that is pure clickbait crap. It probably should've been posted in the pub as a laugh not in Engineering Disasters.

Keith Cress
kcress -
 
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So, a serious question here: looking at the pictures, it's clear that water is coming into / out of the spillway at the joints.

So the takeaway is that the spillway is not intended to be sealed? That, as designed, water should be able to leak into and out of the spillway? Is this a good thing, a bad thing, or just a normal annoyance that has to be dealt with some how?

 
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My interpretation of the photos is that the water is not coming out of, or thru, the spillway. The water leaks past the dam gates. As it descends, it pools at the lateral joints, until at some point (and at a different location) it descends the spillway again, until it hits the next lateral joint.
 
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Keith - 100% for sure, none of those 3 sites (thinker, checker or palmer) belong here, especially as proof of anything.

As for the water in the picture, I would tend to agree with Pete K as to the cause. It's appearing likely that the spillway will get tested soon which will prove it's correct or not.

As for comments/concerns about water/pressure built up behind the spillway concrete. I'm pretty sure the new spillway incorporates drainage behind it, like the original one had drainage behind it. That would remove any possible water/pressure build up behind it and the ability for any water to be pushing through the concrete to the front face.

 
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msquared, I just want to clarify; I was only paraphrasing the statements from a few supposed experts that were linked or quoted previously that claimed there's no problem with the spillway. I agree with you that it's something that should be evaluated up close by qualified person or team (and maybe it has been; that isn't clear from what I've read so far). I would definitely classify the article in the OP as ignorant fearmongering, though.

"I'm pretty sure the new spillway incorporates drainage behind it, like the original one had drainage behind it."

That doesn't instill alot of confidence, considering what happened to the original one...I hope they improved it this time around.
 
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The California Department of Water has an EXTENSIVE set of picture galleries that document pretty much every step of the reconstruction of the spillway at:
One need only scroll back a few pages to see many, many, pictures of the massive under-slab drainage that was installed:


The reconstruction of the spillway was also 'overseen' by an independent engineering panel of experts, and all their reports are public:


If you want to see the 'leaking water' yourself, you can even see a webcam:


It is hard to imagine how this entire project could have been more open and transparent. For much of the project, you could literally be a 'sidewalk superintendent' to one of the largest engineering projects in the country.
 
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TenPenny said:
...looking at the pictures, it's clear that...
Click to expand...

The best most mass-media photographs will ever do is "strongly suggest" or "be consistent with" a hypothesis.

--Bob K.
 
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Some good reporting here on the roots of the failure in 2017 here:

Which cites a 7 page report here:

And alternative analysis here by Robert Bea, a UC Berkeley professor emeritus and co-founder of the school's Center for Catastrophic Risk Management here:

The report noted that the standards for removing loose rock and soil from the foundation of the spillway were relaxed during construction.

The anchors that held the spillway to a mountainside were not strong enough, the report said, and the drains under the spillway were not designed to handle all of the water that penetrated into the foundation.

Other findings included: Crack repairs or new damage allowed more water to penetrate under the spillway; shallow voids developed under the concrete; metal rebar in the concrete corroded; and the concrete deck in the area where the spillway covered drain pipes was only seven inches thick, not the 15 inches that was supposed to be the minimum design thickness.

Also, the uplifting force exceeded the weight of the concrete deck and all of the water that was rushing down the spillway. It also exceeded the anchoring system that tied the deck into the hillside, the report found.
Click to expand...

The IFT believes that the following factors were either not involved or had only a small effect in contributing to the failure:

•Cavitation: The conclusion that cavitation was not a significant factor is based on computations for historic flows and visual observations of the remaining downstream chute, where telltale indicators of incipient cavitation were not found.

•Groundwater [AKA "LEAKAGE]: The geological features and visual evidence of groundwater flow indicate that the amount of groundwater flow was minor, and could have easily been accommodated by the slab underdrain system.

•Seismic damage: A review of seismic activity in the project region, since the last larger flow in 2006, indicates no ground motions large enough to have significantly affected the stability or condition of the spillway chute.
Click to expand...
 
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Has anyone done analysis of pancreatic flow line changes at dam due to spillway failure?
What is elevaTion of green spot on dam? Is it same height as current leak under repaired spillway? If yes then it i
is probably fed by groundwater.
I think the phreatic flow line split in two when dam spillway failed.
The lower one is NOT the issue. The upper one is.
From pics of failed spillway.....huge hole.....it seems that it was deep enough to intercept the original parabolic flow line.
A new flow line was established that entered into hole or void. The sand particles reorient themselves to support this new flow line.
If no work was done to firmly reestablish the original parabolic flow line...... This new one continues and surfaces under the repaired
spillway.
Ca. Spent over 1 billion to harden a 60 year old design. No new tech or model and Simulation was done to improve a PROVEN failed design. Not great investment strategy.
Comments?






 
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@jcirish

Yeah, I would suggest you read the Independent forensic team's report, which stated in part:

"The IFT believes that the following factors were either not involved or had only a small effect in contributing to
the failure:
[..]
Groundwater: The geological features and visual evidence of groundwater flow indicate that the
amount of groundwater flow was minor, and could have easily been accommodated by the slab
underdrain system.
"

 
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Every single image or video of the "leakage" also shows water in the chute coming directly from the gate; it seems pretty likely, therefore, that the "leakage" is not from water coming through the concrete, but is due to the gate water traversing the joints and then spilling out.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! faq731-376 forum1529 Entire Forum list
 
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Which is EXACTLY what Juan Browne reported in the video posted by EdStainless on 19 March.

At this point, I have more faith in what Juan has reported than just about anyone else since he was been on top of this situation since the very beginning and has fallowed it continuously since then, including participating in the teleconferences as well as visually inspecting the area both on the ground and from the air.

John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without
 
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