Thursday, May 18, 2006

Three Gorges Dam Update

It looks like our friends in China are nearing completion on the damn dam that I wrote about a few months back. Here’s an article I read this morning:

China is about to finish erecting the last segment of the Three Gorges Dam, its biggest construction project since the Great Wall.

On Saturday, workers will pour concrete to top off the dam, concluding a mile-and-a-half barrier that eventually will extend a vast reservoir 370 miles up the Yangtze River.

"We cannot say the Three Gorges project is perfect. We'll have to wait 30 years to make that judgment," said Cao Guangjing, the vice general manager of the construction company for the project.

Yet much of China seems to be feting the dam as a symbol of the nation's global power and vitality at the outset of the 21st century.

After a celebration at the dam on Saturday, workers will still need until 2008 to finish auxiliary projects, such as a ship elevator, and install all of the 32 turbines that will power the world's biggest hydroelectric project. When the last turbine whirs to life, the dam is expected to provide one-ninth of China's gargantuan energy needs.

China says the $28 billion dam will help reduce the frequency of killer floods in the lower Yangtze, generate power equivalent to that of 18 nuclear plants and ease seagoing vessels' navigation deep into western China, where development trails the booming coast.

Almost since day one in 1993, tremors of protest have erupted near the Three Gorges Dam, which sits alongside a geologic fault line. Its environmental impact remains a heated issue. Some people already uprooted by the huge reservoir's footprint complain bitterly of inadequate compensation. About 160,000 of them will be forced to reside far from their original homes, not just on higher ground.

China's ruling Communist Party stifles nearly all criticism, and so the dam has come to symbolize not only China's strength but also other facets of China's rise, including its disregard for the environment and authoritarian control of the peasantry.

Authorities recently cut the phone line to one of the most vociferous peasant critics of the relocations, Fu Xiancai. He couldn't be reached Wednesday.
Dai Qing, a Chinese writer and longtime opponent of the dam, calls the Three Gorges Dam "a ridiculous and evil farce" that will haunt China's leaders.

The final verdict on the dam hasn't been delivered, though. On Wednesday, the project's managers squired around three busloads of foreign journalists to peer down the impressive spillway from the 600-foot high dam's rim. The managers touted the security measures in place should disaster - natural or manmade - strike the project.

"We are completing the dam eight months ahead of schedule," said Wang Xiangtan, the deputy director of dam construction, as he signaled the final spot where concrete will be poured Saturday.
The next big test for the dam will begin in late September, when the level of the upstream reservoir will climb to 512 feet, then toward an eventual top height of 574 feet in 2009, leaving vast new areas inundated. The flooding is expected to trigger some landslides on steep slopes.
Still to be seen is the impact on wildlife in the river's ecosystem, such as the endangered Siberian crane, the Chinese river dolphin and the huge Chinese sturgeon.

Also yet to be seen is the long-term consequence of the forced relocation of such a huge number of people, eventually numbering 1.2 million. This, one official said, may mark the project's ultimate impact.

"It will determine if the Three Gorges project is successful or not," said Li Yong'an, the president of the Yangtze Three Gorges Project Development Corp.

China says it has prepared for virtually every contingency to protect the dam, which contains twice as much concrete as the Itaipu in Brazil, which was the world's largest dam before the Three Gorges project.

"Last November, we conducted anti-terrorist maneuvers at the dam site," Cao said. "We can rule out the possibility of dam failure from terrorist attack."

If enemy warplanes make a run at the dam, as a U.S. Pentagon report last year indicated that Taiwan might do if attacked, "China's military will have the ability to safeguard the Three Gorges project," Cao said.

In the shadow of nuclear war or other cataclysm, Cao said dam overseers would lower the reservoir, which may eventually cover 395 square miles, to prevent a deluge.
"Within two or three days, the whole reservoir will be drawn down," Cao said.

He said seismologists foresee an earthquake with a maximum magnitude of 6 striking the zone, but that the dam can withstand a considerably stronger quake.

The Three Gorges Dam will prevent massive flooding in the lower reaches of the Yangtze River region except when rains reach a scale of once-a-century intensity, said Feng Zhengpeng, a hydropower specialist with China's Three Gorges Power Corp.

Deaths from flooding are a sensitive topic in China. The failure of the Banqiao Dam in central Henan province in 1975 precipitated other dam failures that killed 230,000 people, the deadliest dam-related disaster in history. News of the calamity was officially hushed for two decades.
Three Gorges officials still fend off questions about construction quality following reports in 2000 of small cracks in the dam's left bank.

"The cracks are mainly surface cracks. They will not affect the stability of the dam," said Wang, the deputy construction director.

Guess they forgot about this:
"At the beginning of August in 1975 an unusual weather pattern led to a typhoon (Pacific hurricane) passing through Fujian Province on the coast of South China continuing north to Henan Province, (the name means "South of the (Yellow) River.") The rain storm that occurred when the warm, humid air of the typhoon met the cooler air of the north. This led to a set of storms which dropped a meter of water in three days. The first storm, on August 5 dropped 0.448 meters. This alone was 40 percent greater than the previous record. But this record-busting storm was followed by a second downpour on August 6 that lasted 16 hours. On August 7 the third downpour lasted 13 hours. Remember the Banqiao and Shimantan Dams were designed handle a maximum of about 0.5 meters over a three day period.

By August 8 the Banqiao and Shimantan Dam reservoirs had filled to capacity because the runoff so far exceeded the rate at which water could be expelled through their sluice gates. Shortly after midnight (12:30 AM) the water in the Shimantan Dam reservoir on the Hong River rose 40 centimeters above the crest of the dam and the dam collapsed. The reservoir emptied its 120 million cubic meters of water within five hours.

About a half hour later, shortly after 1 AM, the Banqiao Dam on the Ru River was crested. Some brave souls worked in waist-deep water amidst the thunderstorm trying to save the embankment. As the dam began to disintegrate one of these brave souls, an older woman, shouted "Chu Jiaozi" (The river dragon has come!) The crumbling of the dam created a wall of water 6 meters high and 12 kilometers wide moving. Behind this moving wall of water was 600 million cubic meters of more water. Altogether 62 dams broke. Downstream the dikes and flood diversion projects could not resist such a deluge. They broke as well and the flood spread over more than a million hectares of farm land throughout 29 counties and municipalities. One can imagine the terrible predicament of the city of Huaibin where the waters from the Hong and Ru Rivers came together. Eleven million people Throughout the region were severely affected. Over 85 thousand died as a result of the dam failures. There was little or no time for warnings. The wall of water was traveling at about 50 kilometers per hour or about 14 meters per second. The authorities were hampered by the fact that telephone communication was knocked out almost immediately and that they did not expect any of the "iron dams" to fail. People in the flooded areas who survived had to face an equally harrowing ordeal. They were trapped and without food for many days. Many were sick from the contaminated water."

I'd like to think, in my semi-optimistic way that communications have gotten better in the 30 years since the aforementioned floods. But progress is slow to come to rural China.

Sorry to bore y'all with my closet Engineering Geek obsession with this dam, but I just don't feel right about the whole thing. The environmental impact is horrifying, the cultural impact is even worse.
Nossir, I don't like it one bit.

But it's for the greater good of China, I suppose. Damn people and their lives...

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