Posted on 02/17/2017 11:09:41 AM PST by sevinufnine
Communities just downstream of California's Lake Oroville dam would not receive adequate warning or time for evacuations if the 770-foot-tall dam itself rather than its spillways were to abruptly fail, the state water agency that operates the nation's tallest dam repeatedly advised federal regulators a half-decade ago.
The state Department of Water Resources informed federal dam regulators that local emergency officials "do not believe there is enough time to perform evacuations in the communities immediately downstream of the dam during a sudden failure," according to a Feb. 8, 2011, letter reviewed by The Associated Press.
Absent "significant" advance warning, emergency responders instead would likely withdraw to safer ground and prepare for victims, said the same letter by the Federal Energy Regulatory Commission, which oversees safety of hydroelectric dams, in a summary of the state's conclusions.
(Excerpt) Read more at sfgate.com ...
Oops. I mean of HOW close it is to the dam.
It appears as NO margin of safety with 3 or 4 storms already hitting in succession:
https://www.youtube.com/watch?v=CgBW09wd5so
Where did you get your info regarding the Brown family
property being in the Oro Dam floodplain? No where close
although I would love to see Brown dropped on the intended
water storage side of the dam.
I find it surprising they have let people back in until after this rain passes and they are sure they are ok.
Hate to be cyincal, but this IS California. Broke state who went full head-on for Hillary.
I cannot discount they are hoping for a disaster in order to get millions, if not billions, in federal aid to fix the mess they refused to take action for in the first place!
The St Francis dam disaster..
I looked and see they still have not paid any attention to the parking lot side of that spillway. Thats where it will breach if it does.
I think they will still be able to release enough out of the primary discharge to prevent any water from going over that EM spillway.
They have to prevent ANY water from going over that spillway, PERIOD.
In my seriously uninformed opinion, those below the dam are in a very precarious situation but my advice is:
While the gover-stapo will let you, use this opportunity to get back in, pack up your valuables and get them and your loved ones to higher ground. If you absolutely have to go back have several alternate plans to get to high ground in short order and keep careful watch of the inflows so you can be ahead of the rush when the government lackeys finally do get around to issuing the next evacuation order.
Listen for sirens and Pray the main spillway doesn’t unzip back up all the way to the top without any notice.
What about that spray stuff in a can? I’ve seen the ads on TV, man makes everything waterproof. But it’d take a lot of cans, and they may be aerosol, and that might make it rain more. Nevermind...
They ordered the evac the other day and it took them how long to clear out? These folks that have returned and expect to be able to get away in time will be in for a deadly shock.
Oroville is not just downhill, it’s really close. I would never consider it as a place to live. I’m sorry these folks did. BTW, you ha e to know property values there just went into the toilet.
Wouldn’t the sudden collapse of almost ANY large dam be something you couldn’t escape from?
We simply assume that there will not be immediate catastrophic failures. Otherwise, you might as well crawl under a rock.
What has been the status of this reservoir/dam over the past several years? Has it operated like a normal flood control reservoir in normal climate or has it been so dry in this area that this is something new for those operating it?
This Wiki list of all the dams and reservoirs in California is stunning. Look at the age, height, water acreage and construction types. Very scary that there has been minimum maintenance.
https://en.wikipedia.org/wiki/List_of_dams_and_reservoirs_in_California
Just a total guess, because I am not an engineer or hydrologist, but from my knowledge of structures in general, seems like being a dam, that Concrete wall, built initially on top of a hill, would be attached to bedrock and that the erosion should hit that same bedrock before reaching the lake.
As I said, I could be wrong, but main logic in saying this is they were only worried this collapse causing a 30’ wall of water, if that was not solid bedrock, that 30’ wall breech would rapidly wash away all the soil between it and bedrock.
I think a good portion of the main spillway will be gone next time they shut off that flow and we get to see how big that hole has grown.
Much of the modern world is predicated on assuming disasters will always be impossible. What can you do?
Well, there's your problem, right there.
As another poster has said, I'd never consider living downriver from anything on this scale. Why put so much trust into the hands of bureaucrats that have repeatedly proven themselves to be incompetent?
From my perspective, that appears to be solid bedrock. If it was not, those guys could not be walking around on it without sinking to their neck. The brown part you see is either a different type of bedrock (meaning that is a fault line of sorts between them) or it is dirt/fill that the concrete spillway was poured on.
Just a guess, but my simple explanation would be that I assume the ground moved and the fill settled some point after the spillway was poured, which allowed water to flow under and wash more out, then the unreinforced concrete slab that was designed to be bearing on firm ground, not spanning over a hole, cracked and when water started flowing over it and through the crack it just further eroded it almost instantaneously. I am amazed I don’t see any reinforcing hanging out, whatsoever, so the whole spillway appears to be just a mass of concrete, which just seems stupid to me in a highly seismic area like California.
But you are right, I think there is a cavern there, from water hitting bedrock and forced back under the spillway slab... I am betting that hanging piece of slab is now gone. Probably up to where it was on bedrock again and not on fill. I think this was a picture of the initial hole before it grew the first time? I bet it is quite a bit bigger now that they more than doubled the flow that caused the big damage, it got up to almost 120,000 cfs I think.
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