Oroville Dam

[oldno7]

Dang--looks like a serious problem.

http://www.chicoer.com/article/NA/20...at_pco=cfd-1.0

[oldno7]

Doesn't look good

[oldno7]

See if this video works

https://twitter.com/tvseanb/status/8...126082/video/1

[oldno7]

,.,

[oldno7]

,.,

[oldno7]

Check out this 360* streetview of emergency overflow.

https://www.google.com/maps/place/Or...837453!6m1!1e1

[oldno7]

...

[oldno7]

looks like water starting to breech the emergency spillway

[Iceaxe]

As someone who has done design work on similar spillway failures (1983 Glen Canyon Dam), I think there is a good chance they are going to lose Oroville dam. And if I lived downstream I would not trust what I was being told about everything is safe. While no one in attorney will admit it we came within a couple of hours of losing Glen Canyon Dam in 1983 when the spillway failed and the runoff began to eat into the abutment.

[Iceaxe]

It looks like they are losing the dam as they just ordered an evacuation downstream.

https://www.google.com/amp/www.latim...story,amp.html

[Iceaxe]

I don't think most people understand how terrifying this is. Reports are the water has stopped rising. But the scale of the damage is ridiculously large. Larger than the media or average person can comprehend. It's not like you can just drive 1000 concrete trucks up there. The soil needs to be replaced. New rebar forms made for the concrete. And these aren't your sidewalks 1/4" rebar. These are probably huge 3" inch steel bars formed in caged lattices. Then wood forms placed around them. And then the concrete formed.

I wouldn't be surprised if it took 6 months in perfect weather to fix. The problem is the secondary spillway failed. So if they keep the main slide spillway out of use for the next year they still have to contend with the fact that the secondary spillway failed and will have to be used in a damaged and eroding state. And that area can only be used when the water has reached a certain level. They are flirting with disaster.

Also.... the media is totally clueless on this and keep mixing the two spillways and damage to each up. The media is reporting that the dam shouldn't fail because the emergency spillways are 20 feet lower than the dam. But that is not true as erosion from the spillways are the problem. If they can't repair the spillways rapidly the water will continue to erode the earth wall holding the concrete barrier wall up. There is a huge portion of that concrete damn buried in the earth and without the weight of the earth holding up the dam wall the weight of the water itself can deform the dam and cause a sudden catastrophic failure. When soil fails it just moves and flows like water. There will be nothing to push against that wall of concrete and water.



And more rain is expected on Wednesday.........

[oldno7]

lot of concern, as well, about back flow from the spillway, going to the "toe" of the dam and liquefying it.

There are previous dam failures from this very thing.

[Iceaxe]

This is how the spillway should look:





This is what it looks like now. Notice the missing area to the right of the spillway:









The road beneath the spillway is gone. the boat launch is under water. The water is eroding everything right now and it's only a foot of water coming over the long secondary spillway. its expected to get up to 9 feet according to some reports.

I honestly don't know how they are going to repair the main spillway while there is any rain. they are going to need a drought to lower the water to a point where they can perform repairs. we are talking 6 months of repairs. This is major damage so far.

[devo_stevo]

Dang. That's bad. I hadn't looked into this too much to see where and how severe the damage is, but you're right, Iceaxe. That's beyond bad at this point. If that water washes away much more of that mountain side the water in the reservoir will push that dam opened and it will be beyond ugly.

I'm betting that proper repairs for that are more than 6 months worth of work at this point. And like you said, that's under perfect conditions with no more rain. This is bad news...

[Scott P]

I wouldn't be surprised if it took 6 months in perfect weather to fix.

I'd say longer. It us hard to repair/build dams during spring runoff. Other than seeing the news stories and photos, I don't know how long it would take to fix, but would guess late/fall or winter because of the difficulties of working on dams in the spring and early summer.

[Scott P]

I hope it doesn't happen, but if homes are destroyed, I wonder if the insurance companies will refer to it as an "Act of God" (due to weather conditions) or an "Engineering Failure"? It's going to make a big difference on the payout.

[devo_stevo]

I just heard on the radio that the evacuation order has been lifted. Sounds like things are looking up. Hopefully, it stays that way until they can get some water out of that reservoir and repair that spillway.

[Sombeech]

When did the original damage on the spillway become visible? Did they know there was a crack, or a break in the concrete, and it had finally eroded away?

[oldno7]

I'm guessing this is shopped