torsdag 15. april 2010

Jordskjelvet har skadet viktig damanlegg

Brister damanlegget i Qinghai-provinsen, kan 100 000 menneskeliv gå tapt.

The Qinghai Earthquake and Dams

By Peter Bosshard, Policy Director,
International Rivers Network

Another terrible earthquake has struck China. The 7.1 tremor with an epicenter near Jiegu in Yushu County on the Qinghai Plateau has killed at least 400 people. According to Chinese news reports, the Changu (Old Zen) hydropower dam was damaged by the earthquake, and is "at the risk of collapse at any time." If the dam breaks, it would endanger the lives of more than 100,000 people living downstream. International Rivers' thoughts are with the families of the victims, the rescue teams, the Chinese people and the authorities.

Yushu County, on the upper reaches of the Yangtze River, is a hotbed of planned dam building in China. As we know from more than 100 documented cases [ ] around the world, high dams can trigger earthquakes. There is strong evidence linking the devastating Sichuan earthquake of May 2008 to the Zipingpu Dam.

At this point, International Rivers has not seen any evidence linking the latest quake to dam building in the area. However, the serious seismic risks call for utmost caution in building further high dams in Southwestern China.

Several very large dams are currently being built on the middle reaches of the Yangtze, downstream of Yushu County. There are also plans to build at least 81 large dams on the upper reaches of the Yangtze, the Mekong and the Salween rivers in Qinghai Province and Tibetan Autonomous Region. Two hydropower projects - Nieqiahe and Lagong - have already been built on the Upper Yangtze in Yushu County. Eleven more hydropower projects are under active consideration on the same stretch of the river. In addition, the 302-meter-high Tongjia Dam is being considered as the starting point of the Western route of the South North Water Transfer scheme

China's older dams have a very bad safety record. Between 1954 and 2003, 3,484 of the country's 85,300 dams collapsed. New dams, such as those planned on the Upper Yangtze, can be built to withstand very strong earthquakes. However, the homes, offices and public buildings in their vicinity are not built to the same safety standard. They can be severely affected by earthquakes triggered by dams and by the overtopping of reservoirs.

Given the experience with earthquakes and dams, high dams in seismically active regions such as Southwestern China should only be built if (1) the seismicity around the dam sites is continuously monitored, (2) water levels are not allowed to fluctuate quickly, and (3) all buildings in the reservoir areas are seismically retrofitted before the reservoirs begin filling. As Chinese geologists have informed International Rivers, none of these conditions are currently fulfilled in Chinese dam projects.

Comments Peter Bosshard, Policy Director of International Rivers: "Since many large dams have serious social and environmental impacts, the added seismic risks in most cases make energy efficiency improvements and renewable options such as wind and solar the preferred energy solution."

International Rivers is an environmental and human rights organization with staff on four continents. For over two decades, International Rivers has been at the heart of the global struggle to protect rivers and the rights of communities that depend on them.

Contact: Peter Bosshard, Policy Director, (work) +1 510 848 1155, (mobile) +1 510 213 1438,

International Rivers