It's finally done-The Three Gorges Dam

Finn McCool

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China Completes Dam Across Yangtze River By CHRIS HAWKE, Associated Press Writer
1 hour, 23 minutes ago



BEIJING - China finished building the Three Gorges dam across the Yangtze River on Saturday, a key milestone for the world's largest hydroelectric project.

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The 1.4-mile-long dam was designed to stop deadly floods that regularly ravage China's farming heartland, and eventually produce 22.4 million kilowatts of electricity — enough to light up Shanghai on a peak day with power to spare.

But general manager Li Yongan cautioned, "We still face arduous construction tasks."

The project's power-generation facilities will not be finished until 2008 — a year ahead of schedule, according to official estimates.

More than 1.13 million people have been relocated to make way for the dam and its reservoir, according to an official estimate.

Begun in 1993, the project steamed ahead with the backing of the communist leadership despite objections to its $22 billion cost and environmental and social impact, including the inundation of historical relics.

The dam will start protecting people from floods right away, Li said.

"Even if there is a major flood this summer, the Three Gorges Project is capable of regulating flooded waters in an effective way and preventing 15 million people on the middle and lower reaches of the Yangtze River and their property from suffering damages," the official Xinhua News Agency quoted Li as saying.

Environmentalists and engineers have warned that the reservoir risks becoming polluted with waste from cities and towns upriver, many of which lack adequate sewage treatment.

Staccato from paper firecrackers, a burst of confetti and a brief speech marked the completion of the 607-foot high dam.

Plans for a more elaborate celebration were canceled, Xinhua reported, without giving a reason. Elaborate state celebrations have been rolled back amid a growing disparity between the urban rich and rural poor.

Well, it's finally done. It took a long time, and I think China made the wrong decision. It's not worth moving as many people as they moved and destroying as many things as they did. But if oil goes much higher, I'll have to change my mind.

Undoubtedly the dam is a massive enginnering feat. Most people do not think of building a dam, even one this size, as a technological achivement but it is. It helps build an experienced corps and culture of enginering with applications in other areas.

PS-I don't know if this is in the right place; you can move it if you want but I didn't think it belongned in the Club Room.
 

swimmerXC

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Moving this to Club Room
The dam itself is done, but it won't be in full operation till 2009. Although some turbines are already generating power.
China's mega dam built to defy attacks from terrorists, enemies
AGENCE FRANCE-PRESSE
Thu, 18 May 2006, 01:37

YICHANG, CHINA: China's Three Gorges Dam across the Yangtze River, the world's largest hydropower project, shows the nation at its most powerful, but also makes it vulnerable in entirely new ways.

For the past nearly two decades, during design and construction of the dam, planners have engaged in a low-key effort to make sure it is protected from hostile forces -- whether terrorists or nations at war with China.

The measures they have come up with range from building an extra-solid structure, to posting elite paramilitary troops in the immediate vicinity of the dam and, if all else fails, quickly emptying the reservoir.

"The security of the dam, and in particular protection against terrorist attack, is something we take very, very seriously," said Cao Guangjing, vice president of the China Yangtze Three Gorges Project Development Co.

"We paid special attention to preparation against military attack in the preliminary design phase of the dam," he said.

The spirit of immense confidence and pride that permeates the entire Three Gorges project also affects most engineers' attitude towards the idea of an attack on the 2.3-kilometer-long (1.42-mile-long) dam.

"Nothing will happen," said Feng Zhengpeng, director of hydropower complex management. "China is rising and I'm not afraid any nation will attack. Anyone that wishes to attack China today has to think very carefully about it first."

That may be, but history shows dams are tempting targets in war.

In 1943, at the height of the Second World War, Britain's Bomber Command destroyed two dams in Nazi Germany, wreaking havoc on its infrastructure and killing more than 1,000 people.

In its 2004 report to US Congress on China's military power, the Pentagon also suggested that an attack on the dam might be one of Taiwan's options in case of war with China.

"Since (Taiwan) cannot match Beijing's ability to field offensive systems, proponents of strikes against the mainland apparently hope that merely presenting credible threats to China's urban population or high-value targets, such as the Three Gorges Dam, will deter Chinese military coercion," it said.

In one of the more obvious signals of China's security precautions, a detachment of the paramilitary People's Armed Police is kept just next to the dam.

"What you can actually see is just one piece of the effort," said Cao. "We have emergency plans to cope with all possible eventualities."

According to earlier reports in the state media, China has deployed military helicopters, patrol boats, armored vehicles and bomb disposal units near the 180-billion-yuan (22.5-billion-dollar) project.

China has conducted several rounds of anti-terrorist exercises in the area, including one that simulated an assault with a boat brimming with explosives.

The dam is robustly built, and officials say it will be able to withstand any conventional attack, whether from terrorists or from hostile foreign powers.

It is also located more than 1,000 kilometers (620 miles) from any coastline, making it a harder target, Cao argued.

The worst-case scenario would be an assault with a nuclear weapon. In that case, China has only one option, according to Cao.

"If there's a nuclear attack, the main procedure will be to draw down the whole reservoir," he said. "The Three Gorges dam is equipped with sufficient flood discharge capacity."

The crucial job to get done before the enemy can strike is to empty the reservoir of the 22 billion cubic meters (770 billion cubic feet) accumulated above the 145-meter mark.

That could be done in as little as two to three days, as the dam is able to release up to 110,000 cubic meters per second, Cao estimated.

It takes a lot less time for a nuclear missile to strike, and if these precautions fail, and the dam takes a direct hit, disaster would be impossible to prevent. The only question would be how much it could be curbed.

But officials claim computer simulations have shown that the damage would not go all the way down to Shanghai where the Yangtze spills into the East China Sea.

"While preparing for the dam, we conducted a lot of studies into what would happen if it were destroyed," said Wang Xiaomao, deputy chief engineer at the Yangtze River Water Resources Committee.

"Even if there is a war and the dam is wracked, there'll be limited damage."

The state-controlled China Daily newspaper reported last year that channels had been dug out downstream to divert excess water released from a wrecked dam.

Officials said probably the best argument for going ahead with the dam was the idea that nothing would ever be built if you were overpowered by anxiety that it might be broken.

"The construction of the Three Gorges dam will be very beneficial to China's economy, and we should not give up this development opportunity just because we fear war," said Cao.
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crazyinsane105

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An impressive feat this is for China to complete. Congrats to all those who made this dam a reality. :china:

Another thing I would like to mention is that this dam is probably not going to be able to be destroyed by conventional military means (some analysts have suggested that Taiwan may target the dam and destroy it during a war with China). Withotu the use of either tactical nuclear warheads or dozens of daisy cutters, I don't know of any other conventional weapon that can be used to destroy this magnificent piece of work.
 

duskylim

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My Dear Sirs,

Few large-scale projects offer the opportunity for multi-discipline engineering cooperation as do hydro-electric dams. The initial survey involves a study of the geology of the area and the river's hydrology. Having found what appears to be an optimal site, the civil engineers' design the structure of the dam. Like all designs, it is necessary a carefully considered compromise between economy and strength. In addition it usually has to serve several functions... like flood control, irrigation, riverine navigation and power generation. All these were part of the Three Gorges Project.

To convert the impounded waters' static head to electrical power, mechanical engineers then design the power houses and turbines. Is the flow small from a great height, that is a high static head with small discharge, or is it a case of a very large fllow from a small height, large discharge and a low head or a combination of the two? What is the best design? Consideration has to be given to the pattern of the river's flow, the amounts of water to be devoted to power and to other needs. Also provisions for storage or discharge of the impounded water must be made - flood and level control; these include silt control. Once these have been decided, the study of which involves the rivers' flow records covering decades, a decision can be made as to the amount of power that can be usefully extracted. Thus the actual power delivered is always only a portion of the installed capacity.

Once the turbines are designed, it is the turn of the electrical engineers. The generators are designed and in hydro-electric installations these are custom-built to suite their turbines. Provisions have to be made to send out and match the power produced to that of the industry standard, thus you need your own transmission facilities and switchgear.

The watershed surrounding the dammed-up water must be carefully maintained which means planting of forests and their care.

Just a small idea of the problems involved.

Best Regards,

Dusky Lim
 

PiSigma

"the engineer"
hmm nothing to do for us chemical/process engineers.... o well we still have our expensive petro.

i think building the dam is a very good idea. moving a million people is not a big deal in china. in a western nation it's a big deal because there's aren't that many people, but a county in china would have a million people. these 1 million is also a million that doesn't contribute to the economy that much, but if you think of Wuhan, a city of 10 million just 100 kms from the dam that's a industrial hub and center for china's diesel sub manufacture, the conditions of the city is much more important than a million peasants that can only grow enough for themselves.
 

sumdud

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I agree with Finn McCool. The Yangtze keeps collecting sediments on its bottom, contributing to worst floods and higher, worse walls. Then when the flood comes, how will they handle the floods? (Especially something like the flood of 1998)

But great feat? Yes, definitely.
 

SampanViking

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Hi Steelbird

A small question: does china build the whole project with indeginous stuffs and technology?

Much is indigeginous, but some specialised items are outsourced. Currently theya re negotiaiting with a german Firm to provide the Heavy Ship Lits for the Main Lock, there will proabaly be other similar components as well.

these links to you know where, will tell you all about it.

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duskylim

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Dear Mr Steelbird,

The best short, single English-language resource I have seen regarding the Three Gorges Project was published by Scientific American several years ago. It was a special issue regarding Great Engineering projects. The cover story was in fact the Three Gorges Project. It covers the design, planning, environmental, human impact and construction aspects. There were some very good pictures too.

Now to answer your question, IIRC, first the method of mass pouring of concrete via conveyors and towers was done by a US firm that specializes in that. Much of the large heavy earth-moving machinery was either imported or of foriegn design (I understand that Caterpillars and Cummins largest plants outside the USA are in China).

Further Siemens won most of the design contracts for the heavy electricals, especially the hydraulic turbo-generators which are the largest in the world. The generators and turbines were built by Siemens in China itself as they actually have one of their largest plants there (in Shanghai). Transmission and Switchgear was another item where the Chinese used foreign assistance. The power has to be brought more than a thousand kilometers (via high voltage dc transmission lines) to Shanghai! China like Europe uses 50 hz, 240 v power.

The initial surveys were conducted way back in the '20s and '30s by Chinese and foreign geologists. The Three Gorges Dam is upstream of what was previously China's largest dam - Gezhouba. This smaller, older dam, completed in the late 1980's (under Teng hsiao ping) served as the training ground for the builders of the Three Gorges Dam. It shares several common features with the Three Gorges dam. It has a step-type ship lock, for example, and also took advantage of a mid-stream island in its structure. So there was already a precedent for the Three Gorges Dam.

The mouth of the Changjiang (the Long River, i.e. Yangtze) river is in Shanghai, where the ground (like most coastal plains) is very flat and marshy. As one proceeds up the river (southwesterly), the terrain goes from flat to very slightly rolling countryside and the ground becomes more wooded (or actually it used to be!) and drier (i.e. better-drained).

The character of the terrain then changes abruptly as one approaches the Three Gorges. Sharp, craggy peaks wreathed in mist appear and the ground rises onto a plateau, already you are some 800 km from the sea!

The river flows through gaps between the mountains and its path, formerly relatively straight now bends and twists sharply. One of these lesser passages is Gezhouba, but the greatest of all is The Three Gorges.

It is quite a sight to behold. Behind you downstream, the countryside looks flat and tame, then suddenly, before you stands a dark, forbidding mountain range, through which you head towards a gap - two and a half kilometers wide, with sheer cliffs on both sides, this is the mouth of the Xichang Gorge and the site of the Three Gorges Dam.

To all those techies who want to see a truly large-scale project... this is a must-see.

Best Regards

Dusky Lim
 
Then when the flood comes, how will they handle the floods?

Well, in 1975, China was hit by 3 typhoons, and heavy rainfall lead to a 1-in-2000-year flood. This flood ended up bursting 62 dams, among them the largest was Banqiao Dam. Approximately 26,000 people died from flooding and another 145,000 died during subsequent epidemics and famine. In addition, about 5,960,000 buildings collapsed, and 11 million residents were affected. Economic damages were in the tens of billions. One of the main causes of the damn failures were to sedimentation and an inadequate number of sluice gates. Banqiao Dam, for one, was built with 4 less sluice gates then it was deemed necessary to handle a major flood. Also, sedimentation compounded the problem by clogging the sluice gates and rendering them unopenable. Let us hope Chinese engineers learned from the disaster of 1975 and did not make the same mistakes with Three Gorges.
 
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