World

After erecting Three Gorges dam, China warns of its perils

Landslides on the banks of the Yangtze River are attributed to the Three Gorges Dam.
Landslides on the banks of the Yangtze River are attributed to the Three Gorges Dam. Tim Johnson / MCT

MIAOHE, China — Earlier this year, on a slope far above the mighty Yangtze River, Qu Wanfu felt the earth give way. Terrified, she dashed into her house.

"The earth was moving down the hillside," Qu recalled.

Luckily, the landslide stopped, saving this village of about 50 households from careening into the muddy waters of the Yangtze, the largest river in Asia, in a gorge far below.

A few bends downriver, the Three Gorges Dam, said to be the world's biggest civil works project, spans a mile and a half across the Yangtze. Nearly a year and a half after it was completed, the government still touts the $26 billion dam as a showcase project that limits disastrous seasonal flooding and generates vast amounts of electricity.

But authorities now admit that the dam is generating major problems. It's created a huge — and heavy — reservoir pressing against the mountains along the Yangtze, making them more prone to landslides. The deep reservoir stretches upriver about 370 miles, impeding the natural flushing action of the river and trapping pesticides, fertilizer and raw sewage. Downriver from the dam, water flows cleaner and faster, adversely affecting aquatic species adapted to sediment in the river.

Authorities are finally letting reports of the dam's problems reach the public in an apparent bid to pre-empt criticism should disaster unfold. And it's disaster that the official Xinhua news agency forewarned of in an unusually blunt report two weeks ago during a forum on the environmental consequences of the project.

"If no preventive measures are taken, the project could lead to catastrophe," the Sept. 26 Xinhua report said, paraphrasing unnamed "officials."

The report cited Tan Qiwei, the vice mayor of Chongqing, a sprawling city at the head of the reservoir, as saying that slopes along the Yangtze had collapsed in 91 places and a total of 22 miles of land along the river had caved in.

"We cannot take the problems too seriously. We should never sacrifice our environment in exchange for a flash of economic prosperity," Wang Xiaofeng, the head of the executive office of the State Council Three Gorges Project Construction Committee, told state media.

The middle reaches of the Yangtze meander through a subtropical region, slicing through gorges in ancient limestone mountains, some covered with looser rock or soil.

"In general, most of the area is quite stable," said Ioannis Fourniadis, who recently received his Ph.D. from Imperial College London in landslide-hazard modeling along the Yangtze. "Three-quarters or 80 percent of the area is stable. But softer parts with soil, where people are more likely to settle, are likely to have slope failure."

To make way for the reservoir, authorities relocated about 1.3 million people, moving them away from the rising river and allowing 100 or so towns to submerge slowly under floodwaters rising more than 500 feet. As new landslides loom, more relocations are taking place.

Now, it's the turn of the 300 or so residents of Miaohe, who dwell on a high mountain slope dotted with dwarf orange trees and fields of corn and sweet potatoes.

Mud-brick homes in Miaohe cracked when the first landslide hit April 11. The earth moved for a few seconds, then stopped. The ground shook again the next night, residents said, leaving 21 homes damaged. Afterward, officials ordered residents to move into a mountain tunnel a mile away for safety.

"We were forced to live in the tunnel for three months," said Han Yong, a 31-year-old farmer. "It's really wet and noisy in there."

Fields went largely untended, allowing wild boars to descend from the mountains and devour much of the crops.

Regional authorities deployed bulldozers to flatten and fortify a mountain flank a short walk from the village, and government loans are available so that villagers may construct sturdy brick homes there. Some villagers have declined; they want to stay in their ancestral village.

"The government has threatened that if we don't leave here by December we'll have to return to live in the tunnel," Han said. "All the houses here will be razed."

The rising Yangtze has caused other woes, including higher winds in the gorges.

"The dam has brought harm to local people's lives even though it is a great project with lots of benefits for the country," Han said.

China's communist leaders ordered work to begin on the Three Gorges dam in 1993, foreseeing the world's largest hydroelectric project. The showcase dam, first envisioned nearly a century ago, towers 600 feet and holds back 20 billion tons of water in the reservoir. When all 26 mammoth turbines are operational, perhaps within two years, the dam may provide a tenth of China's electrical needs.

Experts said engineers had toiled for decades over the project and knew that the massive reservoir was so weighty that it might cause earth tremors.

Some landslides have sent walls of water more than 100 feet high crashing across the reservoir to the adjacent shoreline, causing even more damage, Huang Xuebin, the head of the Office to Prevent and Control Geological Disasters in the Three Gorges Reservoir, told the forum last month.

The environmental problems have proved especially nettlesome.

"The quality of the water is much worse than we expected, especially in the tributaries," said Weng Lida, the former chief of the Yangtze River Water Resources Protection Bureau, a government agency, who now works for a regional trade group.

Many tributaries along the Yangtze are experiencing algae and aquatic blooms because the water flows have slowed markedly amid a buildup of pollutants, he said.

"In the reservoir area, the water is quite static. That significantly reduces the cleanup capacity, the purifying capacity. In the harbor areas, there is almost no flow," said Li Lifeng, the chief of the fresh water program for WWF China, a branch of the global environmental-advocacy group.

The amount of raw sewage pouring into the river has doubled this decade, and huge trails of flotsam commonly entangle its waters.

"There are millions of tons of floating rubbish that cannot head downstream. This matter compresses and sinks to the bottom of the reservoir. Gradually, it will ferment and produce marsh gas," said Wu Dengming, the head of the Green Volunteer League of Chongqing, a nonprofit environmental group.

The Yangtze River is home to some 350 species of fish, many of which also have been affected by the Three Gorges dam and scores of dams along its 700 tributaries.

"Sixty percent of those fish need navigation between rivers and lakes. So if those fish can't migrate, they can't spawn," said Li of WWF China.

Along the winding mountain roadways high above the reservoir, meanwhile, work crews labor to fortify slopes with lattice structures anchored with cement posts.

Fourniadis, the expert in London, said he thought that authorities would have to relocate more people out of the reservoir area: "I don't think anything else can be done except move people to more stable areas."

Han, the Miaohe resident, said the dam had been her village's bane: "There were no landslides before the dam was built."

(McClatchy Newspapers special correspondent Fan Di contributed to this article.)

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