Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Oroville Dam: Feds and state officials ignored warnings 12 years ago

mercurynews.com

Post reply on HN
Print view View original

41–50 of 64 posts

Re: Oroville Dam: Feds and state officials ignored warnings 12 years ago

#41

Post by tbabb »

throwawaydbfif wrote: post #35
orthoganol wrote: post #32

From what I gathered the main spillway is quite damaged with a ~ 200' x 30' eroded hole in the center, potentially eroding into the supporting hill. It was a problem even before they doubled the outflow to 100,000cfs yesterday which I believe is still the current flow. They want to get the lake down 50' to shutoff the spillway and assess repairs, but even at the current (high) release rate it appears they can only lo…

I get the feeling the dam is likely doomed and they're trying to drain the lake as much as possible to decrease the force of a break

The spillway is kind of "around the corner" from the main dam, so I would guess the latter is probably not "doomed," at least at this point.

A realistic disaster scenario would be if the erosion retreats all the way back to the main spillway gates, or if it undermines the emergency spillway. The berm there would then fail, which holds back maybe 15 or 20 feet of lake altitude. A volume of water equal to that depth times the surface area of the lake would then exit over the hillside, completely uncontrolled. That would be more than enough to cause a serious downstream disaster.

The water flows would be very high (~a million CFS? total guess) which would cause even more severe erosion on that hillside. At that point the main dam might be at risk if the erosion traveled far enough laterally.

Re: Oroville Dam: Feds and state officials ignored warnings 12 years ago

#42

Post by Bombthecat »

yread wrote: post #25

I was just wondering about it the other day while researching the topic: why are there so many dam failures in the states? https://en.wikipedia.org/wiki/Dam_failure#List_of_major_dam_... Since 19th century US has the most (well, at least a lot) dam failures. Is it because there are so many? Are they privately owned and the owners just count on declaring bankruptcy if it fails? Is it the engineering, the geology, the…

My motto: when in doubt, count on greed.

Re: Oroville Dam: Feds and state officials ignored warnings 12 years ago

#43

Post by Bombthecat »

tajen wrote: post #39
throwawaydbfif wrote: post #35

Earlier quoted context omitted.

I get the feeling the dam is likely doomed and they're trying to drain the lake as much as possible to decrease the force of a break

Indeed, 13 times more dams than France (who prides itself for 12% hydroelectricity), while USA is only 5 times bigger in population. China has the most number of large dams in the world: More than twice the USA, for 4x population. http://www.icold-cigb.org/article/GB/world_register/general_...

That's... Quite impressive...

Re: Oroville Dam: Feds and state officials ignored warnings 12 years ago

#44

Post by x0x0 »

hueving wrote: post #14
beatpanda wrote: post #2

This is what California always does. We forget about what happens in a drought as soon as the rain comes, and as soon as the rain comes, we realize we forgot about what happened the last time it flooded. After the catastrophe is already upon us, recriminations fly, trillions of pixels are wasted on heavy-handed think pieces, and we forget again, only to wonder why an entirely preventable tragedy managed to find us th…

Outrage and complaining is much easier than action. During the drought, the best thing we got for legislation to 'fix' it, was preventing people from getting water without explicitly asking at restaurants. As idiotic at this was (this accounts for approximately 0.0% of water use in California), activists rejoiced over how they were fixing the problem by having everyone 'chip in'. Meanwhile farmers continued on not ev…

One almond requires over a gallon of water, and you can buy a pound of raw almonds for $8 or so at my grocery store. But that 1/16 gallon glass of water is gonna save the day.

Meanwhile, our state capital is -- wait for it! -- building out water meters so they can tell how much each house is using. They're trying to get 80% of households by 2025.

Re: Oroville Dam: Feds and state officials ignored warnings 12 years ago

#45

Post by gonzo41 »

Bombthecat wrote: post #42
yread wrote: post #25

I was just wondering about it the other day while researching the topic: why are there so many dam failures in the states? https://en.wikipedia.org/wiki/Dam_failure#List_of_major_dam_... Since 19th century US has the most (well, at least a lot) dam failures. Is it because there are so many? Are they privately owned and the owners just count on declaring bankruptcy if it fails? Is it the engineering, the geology, the…

My motto: when in doubt, count on greed.

Think of all the shortcuts happening in all those nuclear plants around the country!

Re: Oroville Dam: Feds and state officials ignored warnings 12 years ago

#47

Post by coldtea »

yread wrote: post #25

I was just wondering about it the other day while researching the topic: why are there so many dam failures in the states? https://en.wikipedia.org/wiki/Dam_failure#List_of_major_dam_... Since 19th century US has the most (well, at least a lot) dam failures. Is it because there are so many? Are they privately owned and the owners just count on declaring bankruptcy if it fails? Is it the engineering, the geology, the…

>I was just wondering about it the other day while researching the topic: why are there so many dam failures in the states?

Given that, anybody want to bet on the safety of nuclear reactors?

Re: Oroville Dam: Feds and state officials ignored warnings 12 years ago

#48

Post by brentdax »

yread wrote: post #25

I was just wondering about it the other day while researching the topic: why are there so many dam failures in the states? https://en.wikipedia.org/wiki/Dam_failure#List_of_major_dam_... Since 19th century US has the most (well, at least a lot) dam failures. Is it because there are so many? Are they privately owned and the owners just count on declaring bankruptcy if it fails? Is it the engineering, the geology, the…

The US is #2 in large dams with about 9,000. China is #1 with nearly 24,000, but their dam construction has almost all been since 1949. So my guess is that it's a combination of the US having many dams, and having had them for many years.

Source: http://www.icold-cigb.org/article/GB/world_register/general_...

Re: Oroville Dam: Feds and state officials ignored warnings 12 years ago

#49

Post by tristanj »

gonzo41 wrote: post #45
Bombthecat wrote: post #42

Earlier quoted context omitted.

My motto: when in doubt, count on greed.

Think of all the shortcuts happening in all those nuclear plants around the country!

For nuclear incidents, I'm worried the next one will be in China, not in the states. China is building dozens of nuclear power plants, too quickly for the amount of trained technicians, critics say. There is also a disregard for nuclear safety standards. Last year there were 16 publicly reported incidents at Chinese nuclear power stations. According to RadioFreeAsia [1],

> Six [of the 16] incidents involved staff members breaching operational guidelines, and four were caused by a lack of internal communication. More worryingly, six were caused by staff members "pressing the wrong buttons."

which shows a lack of training. Another incident, described by the SCMP, tells how a critical alarm system was accidentally turned off 3 months before anyone noticed [2]

>An alarm system monitoring the radiation of reactor coolant at a nuclear power plant in Shenzhen was accidentally shut down for three months before the mistake was discovered, although a safety committee insisted the incident did not constitute a safety breach.

An official on the "Nuclear Power Station Nuclear Safety Consultative Committee" downplayed the incident saying "There was no harm done.", adding "there is always room for improvement for such a large operation."

-

[1] China Nuclear Power Plant Incidents Highlight 'Systemic' Safety Concerns http://www.rfa.org/english/news/china/concerns-0109201712105...

[2] ‘No harm done’: alarm at Daya Bay nuclear plant accidentally deactivated for three months http://www.scmp.com/news/hong-kong/health-environment/articl...

Re: Oroville Dam: Feds and state officials ignored warnings 12 years ago

#50

Post by rhizome »

krapht wrote: post #5

“It is important to recognize that during a rare event with the emergency spillway flowing at its design capacity, spillway operations would not affect reservoir control or endanger the dam,” wrote John Onderdonk, a senior civil engineer with FERC, in the Federal Energy Regulatory Commission’s San Francisco Office, in a July 27, 2006, memo to his managers. “The emergency spillway meets FERC’s engineering guidelines f…

You can't just pave a lake, engineers have to be calculating the dirt spillways as ablative. Water is powerful stuff.
Post reply on HN