Seismic hazard threatens Yangtze project

Even before the huge reservoir behind China's controversial Three Gorges Dam begins to fill up this weekend a rescue operation is being launched further upstream to save the reservoir from being choked by deadly silt.

Almost completely ignored so far in China and outside, a new generation of four dams designed to trap the silt before it reaches the Three Gorges, has got the final go-ahead.

Visiting the site on the Jinsha (Golden Sands) river, the Yangtze's longest tributary, the Guardian has discovered that it lies on the edge of a recognised seismic zone, a potential danger not mentioned in the few published Chinese accounts.

At Xiangjiaba, the site of the dam furthest downstream of the four, construction will take place right on top of a thermal spring that wells up from a mile and a half underground. The dam will displace the thriving Hot Springs resort built only a few years ago, which sits on a bank of the river opposite a canyon.

A statue of a water nymph looms over the swimming pool, the hot baths and the chalets, all dwarfed by the canyon wall. A little way upstream, villagers still wash down their packhorses on a spit of sand.

"It will be just like the Three Gorges - everything will disappear," said an information officer at the resort headquarters. "At least we have still got a few years to make some money."

Sediment

The dam height at Xiangjiaba will be 160 metres: an even larger one upstream at Xiluodu will reach 270m. Work on Xiluodu will begin this year. Both dams are scheduled for completion before 2020. Two smaller dams are also planned.

However, the Jinsha river lies on the edge of a recognised earthquake zone - identified by the global seismic hazard assessment programme - stretching from the western edge of the Sichuan region to east Yunnan.

"The Jinsha has bad geological conditions, and there is a more severe seismic area upriver from Xiangjiaba," said a Chinese geologist in Sichuan. He added that near this site, dam projects "should not be encouraged".

China's state council has given a definitive go-ahead to the project, even though the feasibility studies for Xiangjiaba are "still being written up", according to a statement. The Jinsha river is the main tributary of the Yangtze, flowing more than 1,200 miles from Tibet to enter the Yangtze at Yibin in Sichuan province, not far below the Xiangjiaba site. Xiluodu's planned hydro-electric power output of 12,600 megawatts will make it "second in world rank", it was announced in March, equal in size to the Itaipu dam on the Brazil-Paraguay border. The Three Gorges will be the world's largest, with a capacity exceeding 18,000MW.

However, official statements admit that the primary motive is to solve the silt problem facing the Three Gorges Dam. The Jinsha project will be built and funded by the same company responsible for the dam.

"Top officials have a headache," said a report from the Three Gorges headquarters, "how to deal with the problem of sedimentation ... The best way is to build more dams upstream to block the silt from entering the reservoir."

The Jinsha river produces more than half the sediment that will enter the Three Gorges reservoir, at an estimated annual rate of 330m tonnes. If unchecked this will seriously reduce the reservoir's lifespan and threaten the operation of the dam's turbines. It is claimed that Xiluodu alone will cut the silt deposit by 36%.

Objections that the reservoirs behind the four new dams will in turn fill up with silt are brushed aside. There is plenty of "dead storage" room to take care of the sediment, the Three Gorges' manager, Lu Youmei, claimed.

Upstream from Xiangjiaba, life continues undisturbed for now. Farming women in blue aprons carry their goods to market, and their babies in circular wicker baskets. Men carry heavier loads strapped to a frame of crossed poles on their backs. In farmhouse gardens, screened by bamboo stands, the peach blossom is in flower. Sand is being dug from the river bed; stone is quarried. In the small town of Xinshi, 31 miles upstream, a restaurant serves its speciality - little "golden sand fish", in a rich soup. Unlike the Three Gorges region, the population is sparse along the Jinsha so the project will attract less attention. Local people do not know how high the dam will be, whether they will be affected, or whether the little fish will survive.

Critics argue that the project is another example of grandiose planning by a powerful political lobby that puts energy first and the environment last.

"It provides the [Three Gorges] project corporation with another golden opportunity to develop, so that it can become a power giant in China," said Mu Lan, editor of the Toronto-based Three Gorges Probe research project. "The corporation is a pet of top leaders such as [the former premier] Li Peng, so it is no wonder that the state council has allowed profits [to be used] from power generation at the Three Gorges to build the new dams. Almost every story put out by the corporation just focuses on the positive aspects of its dams, while ignoring the dark side."

Mr Lu has announced the formation of a firm to "develop the Jinsha and speed up preparatory work" for the first two dams, with an initial budget of nearly one billion yuan (£80m). The Jinsha is described as "a magnificent river with development potential", but environmentalists fear it will be the death verdict on one of China's last untouched natural resources.

Cao Wenxuan, an aquatic life specialist at the Chinese Academy of Sciences, has warned of the danger to the Yangtze river's ecosystem. "If the Three Gorges dam does not succeed in driving certain rare species to extinction, constructing more big dams will finish the job, fragmenting the river into several parts."

There is also talk of 12 hydroelectric schemes, eventually - on the Jinsha producing five times Xiluodu's output. Another huge project involving a "cascade" of eight dams is already beginning in Yunnan province on the Mekong.

The big dam ideology is still alive and well in China, say the critics, and the hidden cost has yet to be added up.

Dam statistics

· The Three Gorges Dam project will create a reservoir 375 miles long, forming the world's largest hydroelectric project

· The first phase to fill it starts on Sunday, raising the water level by 65 metres to 135 metres. The second stage, in six years' time, will raise it to 175 metres

· More than 600,000 residents of the gorges have been relocated. At least 500,000 more still have to be moved

· 26 generating units will have combined capacity of 18.2m kW when they go onstream in 2009

· The dam was proposed a century ago and endorsed by Mao Zedong in the 1950s. It was finally pushed through in the early 90s against opposition in the National People's Congress

· More than 10,000 tonnes of toxic waste have been removed from the reservoir site, but 2,500 tonnes remain

· Critics say the dam will have incalculable effects; it will harbour silt and disrupt the lives of more than 1 million people. A collapse would be catastrophic

· The government claims the dam will satisfy the need for electric power, cut flooding in the Yangtze valley, and that it has been built to the highest standards