China says troops rush to plug dangerous cracks in dam (50 story Zipingpu Dam above Chengdu Plain)

Associated Press via Yahoo ^ | 5/14/08 | AUDRA ANG

[Nexus]

HANWANG, China - Thousands of Chinese soldiers rushed on Wednesday to repair a dam badly cracked by the country's massive earthquake, while rescuers arrived for the first time in the epicenter of the disaster.

China's top economic planning body said that the quake had damaged 391 mostly small dams. It left "extremely dangerous" cracks in the Zipingpu Dam upriver from the earthquake-hit city of Dujiangyan and some 2,000 soldiers were sent to repair the damage, the official Xinhua News Agency said.

Xinhua said Dujiangyan would be "swamped" if major problems emerged at the dam.

He Biao, the director of the Aba Disaster Relief headquarters in northern Sichuan province, said there were also concerns over dams closer to the epicenter.

[Nexus]

"Swamped" is a bit of an understatement, in classic "nothing to see here move along" fashion.

Completed in 2006, the highly controversial dam/reservoir at Zipingpu is a massive 50 story hydroelectic facility built just 7km upsteam from the ancient Dujiangyan Irrigation System, which has protected the Chengdu plain from the Min River since 256 BC.

The dam itself is located only 20km (12 miles) from the epicenter of the earthquake. If it were to breach, it would spell disaster for the already heavily damaged city of Dujiangyan and it's irrigation system, which in turn forks water to the major city of Chengdu downsteam. The cascade effect would "swamp" (i.e. wall of water) the entire basin, making the Johnstown flood look like a walk in the park.

Here is a file photo of a view from above the dam looking down towards the basin:

And a zoomable Google Satellite Map with the epicenter marked by a green arrow:

View Larger Map

The dam is located just to the right of the green arrow if you zoom in.

[Nexus]

Sky News article with a bit more detail:

http://news.sky.com/skynews/article/0,,30200-1315944,00.html

Quake Town Threatened By Cracking Dam

Updated:16:19, Wednesday May 14, 2008
Chinese troops have rushed to plug “extremely dangerous” cracks in a dam wall, upriver from the earthquake-devastated town of Dujiangyan.

The state-run news agency Xinhua said that 2,000 troops had been sent to work on the Zipingku Dam in Sichuan province.

Speaking from Dujiangyan, Sky’s China correspondent Peter Sharp said many local people seemed unaware of the threat.

“It (the dam) is only five kilometres away, we are downstream of it,” he said.

“We understand that some of the People’s Liberation Army troops that are deployed here helping with the rescue operation... 2,000 of them [have been moved] upriver to seal some serious cracks in the dam wall.”

In a separate report, Xinhua said Dujiangyan would be “swamped” if there was major problems at the dam.

It reported that the water resources ministry had set-up an emergency command centre at the dam “to discharge the reservoir’s rising waters and guarantee that the damage posed no threat to Dujiangyan and the neighbouring Chengdu Plain.”

[agere_contra]

That dam is holding back over a billion m3 of freezing cold water. Which is another way of saying a billion tonnes of water. Or one tonne for everyone in China.

[Rummyfan]

Wow. This could be ... REALLY BAD!

[SF Republican]

seal some serious cracks in the dam wall - can an engineer help out here? can something with "some serious cracks" even be repaired?

[Abathar]

Can someone tell me what a couple of thousand unskilled troops are going to do to a 50 story dam that is cracked?

This thing is 500 feet tall, there isn’t enough chewing gum or silicone tubes for 2000 men to have any effect at all. Drain the lake and then pressure fill the crack, pouring another thick face on the lake side of the thing for support.

It will take years to properly repair this dam, assuming there isn’t an aftershock before it’s done.

[Kirkwood]

I wouldn’t hang around and hope for the best. I would get the hell out of there. A simple aftershock could be catastrophic.

[Nexus]

Peter Sharp mentions in the Sky article the most locals are unaware of the threat, and in fact while we were discussing the proximity of this dam to the epicenter yesterday, a local implied that it was “seemingly in control” because no one was talking about it, lol.

[STD]

God alone holds back the water. I pray that He intercedes and keeps that dam holding. Has anyone noticed that over the last month the rash of quakes ,eruptions and typhoons that have killed hundreds of thousands of people worldwide. We have Burma swamped by a cyclone with 50,000 dead and now a quake with the potential 150,000 plus deaths in China. This events occur in threes. Where will the next disaster going to occur? Cali, Hawaii or in Napoli? God only knows? Wake up and repent. get right along side our good God. He’s the only answer.

[Lijahsbubbe]

That dam is holding back over a billion m3 of freezing cold water. Which is another way of saying a billion tonnes of water. Or one tonne for everyone in China

Holy moly. Where'd you get that info? (I swear Freepers have all the info)

[SlowBoat407]

Zipingpu also describes what people downstream from the dam are doing about now.

[STD]

God alone holds back the water. I pray that He intercedes and keeps that dam holding. Has anyone noticed that over the last month a rash of quakes ,eruptions and typhoons that have killed hundreds of thousands of people. We have Burma swamped by a cyclone with 50,000 dead and now a quake with the potential to have caused 150,000 plus deaths in China. These events occur in threes. Where will the next disaster occur? Cali, Hawaii or in Napoli? God only knows? Wake up and repent. Get right along side of our good God. He’s the only answer to avoid an eternity in darkness.

[SlowBoat407]

This events occur in threes. Where will the next disaster going to occur?

This country, in November.

[Nexus]

Here is what appears to be a current pic from the site, from the Sky article. Who knows what the men in the boats are doing, the bubble gum squad I guess:

[STD]

Absolutely Brother

http://chinaview.wordpress.com/2007/02/24/the-high-cost-of-geological-disasters-in-china/

[STD]

Consider, the Chinese knowingly built these damns with poor quality concrete. Those troops are not at the damn to repair it IMHO. The troops are there to keep the journalists away from the awful truth that the dam is crumbling. If it hasn’t washed out already. God Help Them Lord for they know not what they do! Amen

The High Cost of Geological Disasters in China

Posted by chinaview on February 24, 2007

by Fan Xiao, translated by Three Gorges Probe, January 29/2007- (cont’d)

The high cost of geological disasters

The river valleys in which most of China’s big dams are planned, under construction or already built — including the Min, Dadu, Yalong, Jinsha, Lancang-Mekong and Nu — are located in the transition belt between the Qinghai-Tibetan Plateau and the Yunnan-Guizhou Plateau and Sichuan Basin. The geology in this area is unstable, and geological disasters are frequent.

Due to the dramatic variations in topography and landscape, regions such as this are seen, both inside and outside China, as holding tremendous potential for hydropower development. But at the same time, the risk of geological disasters is particularly high, and a number of hydropower projects have been built in this region of southwest China without due regard for the danger.

There are several well-known earthquake zones and seismically active belts in the region, and an average of one quake registering at least 6 on the Richter scale strikes every 10 years. This is also the region of China that is most plagued by landslides, riverbank collapses and mud-rock flows.

For example, in 1989, during construction of the Manwan dam on the Lancang (Mekong) River in Yunnan province, excavation work on the left bank triggered a massive riverbank collapse, which cut off a road on the top of the dam, brought the construction work to a halt and added 140 million yuan (US$17.5 million) to the cost of the project. Since 1993, when the first Manwan generators went into operation, more than 100 riverbank collapses and landslides have been caused by the big changes in water level during the regular operation of the reservoir.

In March 1995, for instance, 51 riverbank collapses and landslides occurred over the course of one week in Jingdong county alone due to the sudden drop of water level from 991 metres to 940 metres. According to official statistics, 2,958 local people had to be resettled for a second time because of geological disasters triggered by the dam — almost as many as had to be relocated for the dam in the first place (3,042).

In 1996, the Geheyan dam was completed on the Qing River, a tributary of the Yangtze below the Three Gorges. When the Geheyan reservoir was filled for the first time in 1993, rising from 132 metres to 200 metres, deformations began to appear in the Maoping landslide located 66 kilometres upstream of the dam. The landslide had been stable for years and had shown no signs of deformation before the filling of the reservoir.

But now, in the past few years, the huge Maoping landslide, which has a volume of 24 million cubic metres, has started slipping again. If it were to slide into the river, the Qing would be completely blocked and make another big dam upstream unworkable. This is the 233-metre-high Shuibuya dam, currently under construction 90 kilometres upstream of Geheyan and scheduled to be completed in 2008.

In 2001, at the Zipingpu dam site on the Min River, excavation work on the slopes, combined with several days of rain, triggered large-scale landslides and mud-rock flows, blocking a national highway and causing other economic losses.

Dam-induced seismicity is another major problem. As many as 15 earthquakes triggered by dams have been recorded in China.

One of the most serious such tremors occurred near the Xinfengjiang reservoir on the Dong River in Guangdong province. Seismic activity was detected just a month after the reservoir was filled in 1959. And then, on May 7, 1962, a powerful earthquake registering 6.1 on the Richter scale shook the area, with the epicentre only 1.1 kilometres upstream of the dam. The quake killed six people, destroyed 1,800 houses and caused an 82-metre-long crack to open in the structure of the dam, rendering it unworkable. The incident was ranked as one of the world’s six most powerful earthquakes above 6 on the Richter scale that have been triggered by dams.

Two big earthquakes, also above magnitude 6, were reported in Dayao, Yunnan province, in July and October 2003. The tremors damaged 54 large and medium-scale reservoirs built on tributaries of the Jinsha River. Many of the structures developed cracks and began to leak water, forcing the evacuation of people living downstream.

When a dam is being planned and built, the potential impact of seismic activity is considered, and measures to protect the dam are proposed. However, in a geologically complex area prone to disasters, such as southwest China, this does not mean that the dam will be safe. And this does not mean that the reservoir area or the region below the big dam will be safe.

In China, both the feasibility study and environmental impact study for a dam will focus mainly on a geological assessment of the proposed site and the foundation on which the powerhouses will be built. Little attention will be paid to the valley as a whole where this development will take place.

Furthermore, even when a more comprehensive geological assessment of the region is made, the costs of the potential geological disasters are not often taken into account, either in the cost-benefit analysis or the decision-making process. (END)

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<< Poorly Built, Dangerous Dams and Reservoirs in China

[ClearCase_guy]

Just dam.

[agere_contra]

Cheater that I am, I can't pretend to any great hydrodynamic knowledge. I looked it up here

[okie01]

The incident was ranked as one of the world’s six most powerful earthquakes above 6 on the Richter scale that have been triggered by dams.

How, I wonder, does a dam "trigger" an earthquake?

.

[agere_contra]

I’ve seen the name Fan Xiao before. Journalist examining the corruption surrounding the removal of people from the construction site of ... the ZipingPu dam.

Well that’s odd. One can obviously make a career in China just reporting on one dam thing after another.