quote:

Originally posted by Hound Dog:
Correct me if I'm wrong, though, but if 100,000,000 people all filed claims, wouldn't that bankrupt the insurance industry there and make it all useless?

Yup, there was a lot of companies that went out of business after Katrina, Harvey, Sandy, etc... BUT, we're talking about China, where everything is a sliding scale, to include regulations, compliance and the law.

quote:

Originally posted by cslinger:
So before the damn was in place how did the water run? Now I realize a catastrophic failure of a damn releases a fist of God level of power but before the damn how did these settlements flourish?

The easiest way to answer the first question would be to look at a map of the PRC showing rivers before and after the dam was put in place. IIRC, the rivers should run more or less the same - the big argument for making the dam was to control periodic major flooding along the course of the river. People living there might've had their homes washed away ocassionally (I think some were actually built into cliffs because of flooding) but, as with the Nile, the flooding washed rich silt over the bottomlands that supported some pretty good farming.

Bear in mind that the "big argument" may have been flooding, but the primary payoff for the dams is to provide more water and electricity to new, far more urban, development downstream. Essentially they screwed rural populations to buy off the urban populations that have been growing so fast there since the turn of the Millenium. The dam is essentially early-20th century tech; it's sole function is to flush water downstream as rapidly and in as great a volume as possible.

Yikes. How much of China's areable farmland lies in the path of this potential epic catastrophe? This would be a hard human and economic toll for China to swallow.

Insurance? Ha - they'd all file for bankruptcy protection before the dam finished its collapse. Remember the water / flood damage vs. wind damage court fights over insurance after Katrina?

Let's hope the dam holds, for everyone's sake.

quote:

Yikes. How much of China's areable farmland lies in the path of this potential epic catastrophe?

I don't know the answer, but I would guess a great deal of it. The richest land to farm tends to be riverbottoms; the easiest land to irrigate tends to be flatlands on either side of the river; the most efficient way to actively use land prone to flooding is generally farming.

quote:

Originally posted by ensigmatic:
Holy Toledo! Re: The 2nd video: "Satellite imaging issue" and "a few millimeters" my ass!

"Independent concrete blocks?" "Not [anchored] to the bedrock below?" My Lord. Are they insane?

No, it's called a gravity dam. The sheer weight of the individual units prevents it from washing away.

Grand Coulle Dam in Washington is an example.

quote:

Originally posted by Il Cattivo:

quote:

Originally posted by cslinger:
So before the damn was in place how did the water run? Now I realize a catastrophic failure of a damn releases a fist of God level of power but before the damn how did these settlements flourish?

The easiest way to answer the first question would be to look at a map of the PRC showing rivers before and after the dam was put in place. IIRC, the rivers should run more or less the same - the big argument for making the dam was to control periodic major flooding along the course of the river. People living there might've had their homes washed away ocassionally (I think some were actually built into cliffs because of flooding) but, as with the Nile, the flooding washed rich silt over the bottomlands that supported some pretty good farming.

Bear in mind that the "big argument" may have been flooding, but the primary payoff for the dams is to provide more water and electricity to new, far more urban, development downstream. Essentially they screwed rural populations to buy off the urban populations that have been growing so fast there since the turn of the Millenium. The dam is essentially early-20th century tech; it's sole function is to flush water downstream as rapidly and in as great a volume as possible.

To add - 5x the size of Hoover Dam and 11x the electric output.

Here is a pretty interesting article about the dam, the history and reasons behind it, etc.

https://www.nationalgeographic...s-dam-how-big/#close

quote:

Originally posted by Sig2340:
No, it's called a gravity dam. The sheer weight of the individual units prevents it from washing away.

Grand Coulle Dam in Washington is an example.

Except the Grand Coulee Dam is one, solid, poured concrete structure, no? Probably rebarred?

The Three Gorges Dam is also nearly half again as long and 10% higher.

quote:

Originally posted by tanner:
Does anyone know if those homes and businesses are insured in any way? Does China even have insurance companies as we know them in Western culture? Or are people just SOL with the loss?

Even if they do, and if god forbid this actually happens and there are people still alive to file the claims, something of this magnitude could/would render the insurance companies insolvent.

In addition to probably not having insurance, until recently there were no bankruptcy laws in China. Within the last few years some bankruptcy laws affecting business have been implemented, but personal bankruptcy doesn't really exist. Some regions are just starting to draft legislation now. A lot of people will lose everything with no recourse, not even debt relief.

I'm not a structural expert, but I have some familiarity with construction in China. An Australian construction manager I ran into in Beijing less than 10 years ago was explaining to his colleagues that no matter what amount of steel is specified for a building structure, the contractors will use 10% less (presumably thinner gauge). They know this and over design to account for the missing 10%. Then after watching the construction, upon completion they would inform the contractor that since 10% less steel was used than specified, 10% of the material cost would not be paid. He said the reaction was usually rather negative because the contractor assumed they would not get caught.

So you have two issues here - the design of the dam, and the actual construction. Either or both may not be sufficient. Failure of the dam will be avoided at all costs, so they will most likely just continue to spillover and flood downstream areas until the rains stop.

A good friend of mine in Chengdu works for a non-government relief organization and she has been involved in things like relief efforts after earthquakes. I'm going to check in with her and see what she's hearing about this.

Kyle Bass on Twitter:

quote:

China’s Three Gorges Dam is at severe risk of breaking. The chinese Communists hailed the massive dam as a “1000-year dam” once constructed in 2003. CCP messaging this week is now calling it a “100-yr dam in a 200-yr flood”. They are telling the people to prepare for collapse.

quote:

The scary reality is that the overwhelming majority of chinese (and therefore US) pharmaceutical production is located on the Yangtze River just below the creaking dam. If it breaks, it could be a catastrophe for the people of china AND the United States

https://twitter.com/Jkylebass/...130479856406528?s=20

I'm glad the US is good at spinning up manufacturing whatever they want, quickly.

^^^^^ I keep a continually rolling 1 year supply of my prescription meds.

It took some time and effort to do that.
.

My thoughts as a dam safety engineer:

The downgrading of the dam's capacity from a 1000-year to 100-year structure tells me that they missed the hydrology very badly on this. That could be the result of poor data during design or it could be the result of upstream development that has changed the hydrograph. More development = more paved surfaces = more concentrated flow into runoff channels (i.e. rivers and streams). I'm not an expert on Three Gorges or the upper Yangtze region, so I won't guess on the reason. Regardless, they missed it badly. Three Gorges also has a history of landslides upstream of the dam, many of which have reduced the storage capacity of the reservoir. This could be playing a role as well.

The greatest danger to a dam is typically not the structure itself. The danger is in the foundation and embankments. Every time a new higher water level is reached, the hydraulic head forcing water around and under the dam increases which leads to a greater chance for erosion and piping of the embankment materials. Once the embankment support is compromised, it's nearly impossible to save the dam unless water levels drop quickly. That's the reason that most dams fail during their initial filling or soon after.

My speculation, again without data or specific knowledge of the situation, is that the dam will hold. They are going to keep the flood gates open and try to keep the downstream water level as high as possible to reduce the head differential on the dam. That also, unfortunately, means the downstream areas will not see relief for a while. I suspect they'll save it, but be prepared for some massive retrofit projects after this.

any updates?

are we getting reliable info from the Chicoms?

-----------------------------

Nothing to see here.... move along...



Three Gorges Dam serves to prevent flood disasters with stable operation, company said, refuting distortion, collapse rumors

Exaggerating the Three Gorges Dam's "distortion" has also been somewhat of a cliché for certain overseas media outlets. In response to this cliché, the statement from the Three Gorges Dam noted that currently, the Three Gorges Dam is running safely in a good condition. During the past few years, there has been no so-called distortion occurring, or any other noteworthy risks.

https://www.globaltimes.cn/content/1194924.shtml

Regarding the supposed distortion of the dam, that is almost certainly an artifact of the satellite photos. No concrete dam could withstand that kind of distortion without massive tensile cracks and subsequent structural failure.

There's a saying that I teach my civil engineering students that's applicable to this disaster:
"Nature bats last"

quote:

Originally posted by jaaron11:
Regarding the supposed distortion of the dam, that is almost certainly an artifact of the satellite photos. No concrete dam could withstand that kind of distortion without massive tensile cracks and subsequent structural failure.

There's a saying that I teach my civil engineering students that's applicable to this disaster:
"Nature bats last"

Absolutely, any so called distortion in the dam would have caused a complete failure long before the amount seen in the satellite photos, if that was real.
Another saying I like is "Nature works 24/7/365 to undo whatever you just created."

Here's a good update on the situation. Doesn't look good for them.




Link to original video: https://youtu.be/t5ntYTBwrJE

Poor people.

I wonder how much notice they gave the people that the dam would be discharging water.

Years ago I used to trout fish downstream of the TVA dams. They would perioidically discharge water to control the mosquito populaton and for other reasons. They would sound a loud horn about ten minutes before discharge. You got out immediately. The force of the water coming through that dam was incredible.