The Zangmu Dam is the first of five planned for the 100-kilometre Jiacha Canyon (pictured), which is southeast of Tibet’s capital of Lhasa. However, geologists have said that the area is prone to earthquakes.
“Huge mountains suddenly surged from a piece of flat land, forming two almost vertical walls to the horizon,” geologist Yang Yong told the South China Morning Post. Thus, the canyon “is fresh evidence of violent geological movement. I cannot imagine a more dangerous spot to build dams.”
"The Jiacha Canyon sits right above an enormous, active fault. It is exactly where the tectonic plates of India and Eurasia meet."
"The canyon has, no doubt, trapped an enormous amount of hydroelectric resources," Yang said. “But the site is not safe. Huge earthquakes have struck the region in recent history. Landslides occur often. 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.”
Some seismologists warn that China may have entered a period of more frequent seismic activity, citing the magnitude-8 earthquake that struck Sichuan in May 2008, killing nearly 88,000 people, and the 7.1-magnitude quake that hit Yushu prefecture, Qinghai, two weeks ago.
The five hydroelectric dams in the Jiacha Canyon are only part of a more extensive plan. The largest of them will be in the Yarlung Zangbo Canyon, and will have a capacity of more than 40,000 megawatts—more than twice the maximum capacity of the Three Gorges Dam.
What is more, local residents can be expected to oppose the dam. The Shannan district lies to the west of the Jiacha Canyon and is Tibet’s most fertile region. Building a large dam in the canyon would force some native Tibetan communities to move from the land where they have lived for centuries.
Beijing has countered such arguments saying that the dams would bring security and great economic development to the benefit of LL residents. It noted that power shortages were the biggest obstacle to development in Tibet today. Even Lhasa residents have to endure electricity rationing almost every year.
In the meantime, the dam project is highly controversial in India. Unofficial sources in India have accused China of not only planning to dam the Brahmaputra to generate power, but also of diverting its waters to irrigate arid regions, including the Gobi Desert, which is believed to be expanding by 3 kilometres per year.
Some in India believe that China in fact wants to build a “Western Canal” to carry Brahmaputra waters to the dying Yellow River to augment water supplies to Shaanxi, Hebel, Beijing and Tianjin.
At stake is also the possibility of harnessing the hydropower potential of the river’s tributaries like the Siang, Subansiri and Lohit.
Bangladesh is also an interested party in the matter because it depends on the Brahmaputra for its water.