Dams and Earthquakes

China considers earthquake danger of dams

May 28, 2008

With so many of Sichuan’s dams and reservoirs at risk of collapse, this month’s earthquake “may tilt the balance of public opinion in favour of a more cautious and environmentally conscious approach to such development,” reports the Los Angeles Times.

Barbara Demick writes:Geologists have long warned of the danger of building dams in earthquake-prone locations. Not only can the structures collapse, but some temblors — most famously one in 1967 in Koyna, India — also are believed to have been triggered by the weight of a dam’s reservoir.

Sichuan province’s environmentalists have been fighting against dams for years. In 2003, they managed to stop a project that was to be built in Dujiangyan on the grounds that it would destroy a 2,000-year-old irrigation system that is a World Heritage Site. (The ancient system, only 20 miles from the epicenter, survived the quake virtually unscathed.)

But they could not block another large project, the Zipingpu dam, which opened two years ago over the objections of the Sichuan Seismological Bureau. The government agency said the dam was too close to a major fault line.
 
The warnings proved well-founded. Zipingpu’s concrete face sustained severe cracks May 12 even though it was built to the highest quake-resistant standards. Fan Xiao, a geologist in Sichuan who fought Zipingpu, has called for an investigation of whether the dam could have contributed to the temblor. [See Fan’s explantion of how dams induce earthquakes in yesterday’s Three Gorges Probe]

The area’s Taipingyi and Tongzhong dams also were seriously damaged, Fan said.

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

Dams are something of an obsession for the burgeoning Chinese environmental movement. They are at once the most vivid example of Mao’s call to reshape nature and a symbol of greed in the market economy. Most of the dams built in the last decade are to satisfy the nation’s hunger for hydroelectric power and to generate revenue for local governments. Sichuan province (the very name means four rivers), where the rivers rush down from high elevations, is the most tempting location in China for hydropower.

“We have a saying that bridges are silver, highways are gold, and dams are diamonds. If you get a contract to build a dam, there is so much money,” said Dai Qing, a writer who was imprisoned after the Tiananmen Square demonstrations of 1989 and now devotes herself to fighting against the building of dams.

She and others are demanding an investigation of the role of dams in the quake.

“We must look carefully at the questions: How do dams impact earthquakes. How do earthquakes impact dams,” Dai said.

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