Dams and Landslides

China intent on building more dams in a seismically-active region in Tibet

(May 6, 2010) After months of rumours, Chinese officials have confessed to plans to construct dams in a seismically-active and politically-sensitive region in Tibet’s Jiacha Canyon. The first dam—the 500-megawatt Zangmu hydroelectric project—is currently under construction and is the first of five planned for the scenic, 100-kilometre canyon on the Yarlung Tsangpo River.

But just as reports confirmed plans to build the dam, one geologist is sounding warnings that the dam may be dangerous, due to the region’s seismic activity.

According to the South China Morning Post, geologist Yang Yong says he couldn’t “imagine a more dangerous spot to build dams,” adding that, “huge earthquakes have struck the region in recent history.”

“(The) Jiacha canyon sits right above an enormous, active fault. It is exactly where the tectonic plates of India and Eurasia meet.”

Yang described the area, saying it consists of massive mountains that “suddenly surged from a piece of flat land, forming two almost vertical walls to the horizon.” He noted that the canyon is “fresh evidence of violent geological movement.”

Officials would be wise to consider the possibility of reservoir-induced seismicity (RIS), in which pressure from a dam’s reservoir can potentially trigger an earthquake. Scientists, both in China and abroad, argue that the Zipingpu dam in Sichuan province may have triggered the deadly 2008 Wenchuan earthquake and have been calling for the release of micro-seismic data to better understand what happened at the dam site. Chinese officials have been adamant that the dam had nothing to do with the earthquake, but have yet to release the requested data.

Earthquakes aren’t the only threat, as the region also experiences frequent landslides, says Yang. Other dams, such as the Three Gorges dam, have increased the severity and occurrence of landslides along its reservoir.

Yang believes “such natural disasters not only threaten the safety of the dam—they could be intensified or even created by the dam, which, with its large water supply, could change the delicate geological balance of a large region.”

Meanwhile, building the dam will be no small feat. Citing an academic paper, the South China Morning Post says ordinary construction materials would not be adequate in ensuring the dam’s stability, and special technology developed by China’s space industry programme is now being used. The cement, for example, is reported to have been developed by laboratories at the Xichang satellite launch centre.

And getting those materials to the construction site will be a project of its own, as a lack of proper roads, sufficient oxygen, labour, equipment and technology has, in the past, been a major impediment to building dams in Tibet.

Worse still, local residents are likely to fiercely oppose the dam, as the region just west of where it will be built is one of Tibet’s most fertile regions. According to one news outlet, “building a large dam in the canyon would force some native Tibetan communities to move from the land where they have lived for centuries.”

The dam is also sure to create a political flashpoint with China’s neighbour, India. The Yarlung Tsangpo River originates in Tibet, flows into India through the disputed Arunachal Pradesh state where it becomes known as the Brahmaputra, and then flows through Bangladesh where it is joined by the Ganga River to create the world’s largest delta before emptying into the Bay of Bengal.

Officials in India are said to be concerned that the series of dams on the upper reaches of the river will affect India’s water supply and disrupt the river’s ecological balance—with many farmers and other industries heavily reliant on the river.

“Whether China goes for big or small hydel [hydro-electric] projects, it will definitely have an impact on the flow of Brahmaputra in northeastern region,” Partha J Das, head of Aaranyak’s Water, Climate and Hazard Program told the Times of India.

China, meanwhile, points out that it needn’t have told India it was building the Zangmu hydroelectric project—and only did so to build trust and ease tensions between the two countries. Fears that the dams will disrupt the Brahmaputra in India are also overplayed, says one retired government official. He says the dams, far upstream from the Indian border, will have little effect on the flow of the river downstream.

Others dispute this, however.  Aviva Imhof, from International Rivers said, “the headwaters of most of the major rivers of Asia are in Tibet, so damming them could have implications downstream.”

But what India really fears, and with good reason, is that China intends to use the dams to store water and eventually divert it to water-starved regions in Northern China—part of the Chinese government’s South to North Water Diversion project.

China has already raised the ire of its neighbours in the downstream areas along the Mekong.

“India is just as alarmed about dams on the Yarlung Zangbo as Thailand, Laos, Vietnam and Cambodia are about China’s dams on the Mekong River in Yunnan,” Anant Krishnan, a foreign affairs expert in India said. Arguments between China and the five countries that sit downstream on the Mekong have been ongoing for more than a decade, after China began to relentlessly pursue hydroelectric projects on upstream sections of the river.

Brady Yauch, Probe International, May 6, 2010

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