Did dams play a role in China's deadly quake?

BEIJING --

Mao Zedong famously declared "man must conquer nature," and his political heirs have followed his dictum zealously by building dams and other gigantic projects that have altered the landscape of China.

But the May 12 earthquake may tilt the balance of public opinion in favor of a more cautious approach.

China has more dams than any other country, about half of the world's total, and the presence of so many near the epicenter in Sichuan province has been a huge problem.

After two weeks of downplaying the complication, the Water Resources Ministry has admitted 69 reservoirs and dams were on the verge of collapse, while nearly 3,000 were damaged.

The threat of flash floods has forced tens of thousands of traumatized quake survivors to relocate, some more than once. The dams also prevented rescue workers from navigating the rivers to reach victims in areas made inaccessible after roads were washed out.

Many Chinese ascribe to the belief that natural disasters are the result of human failings and point to the widespread construction of dams as a possible culprit. The Min River, a Yangtze River tributary that runs through the path of destruction, is one of the most dammed-up rivers in the country.

"What we did to that river shows no respect for nature, and now nature is taking its revenge," said Ai Nanshan, a professor of environmental sciences at Sichuan University in Chengdu.

Geologists long have warned of the danger of building dams in quake-prone locations. Not only can the structures collapse, but some tremors -- such as the one in 1967 in Koyna, India -- are believed to have been triggered by the weight of a dam's reservoir.

"We don't want to appear to benefit from human catastrophe by pushing an agenda, but we are making information about earthquakes and dams available," said Peter Bosshard, an official with International Rivers Network, a Berkeley, Calif., environmental group.

It is too late to stop China's $30 billion Three Gorges Dam, the world's largest hydroelectric-power project that is nearly complete. More than 1 million people were displaced to build it.

But environmentalists are likely to use the Sichuan experience to fight a dam on the Nu River in a quake-prone area near the border with Myanmar.

Within days of the May 12 magnitude-7.9 quake, activists scored a big victory when PetroChina announced it would reconsider its plans for a $5.5 billion refinery and petrochemical plant in Pengzhou, 30 miles from the epicenter.

Sichuan province's environmentalists have been fighting dams for years. In 2003, they stopped a project in Dujiangyan because it would destroy a 2,000-year-old irrigation system that is a World Heritage Site. The ancient system, 20 miles from the epicenter, survived the quake virtually unscathed.

But they could not block the Zipingpu Dam, which opened two years ago over the objections of Sichuan seismologists. Their warnings proved well-founded. Zipingpu sustained severe cracks May 12 even though it was built to the highest quake-resistant standards. Fan Xiao, a Sichuan geologist, also has called for an inquiry into whether the dam could have contributed to the temblor.

"Zipingpu is a very large dam with water more than 100 meters deep that causes pressure on the [tectonic] plates," Fan said. "It is right on the fault line. We cannot rule out the possibility that it was one of the triggers of the earthquake."

The area's Taipingyi and Tongzhong dams also were seriously damaged, according to Fan.

Not only did dams crack during the quake, but landslides damaged hydroelectric-power facilities and caused reservoirs to rise to dangerous levels.