The Zipingpu hydropower dam in Sichuan was built in 2002 and completed in 2008, soon after the reservoir was filled and put in operation, on May 12, 2008, a massive earthquake, magnitude 7.9 hit the region and reportedly killed 69,000 people, rendering anywhere from 4.8 to 111 people homeless. China and the world were shocked by the stunning catastrophe, in July 8, 2008, a group of Chinese environmentalists and scholars submitted the appeal to the Chinese government for dam safety assessments in geologically unstable south-west China.

The petition was first reported on in the First Business Daily (Diyi caijing bao) on June 12, 2008 and translated by Three Gorges Probe. The petition is summarized below:

Chinese environmentalists and scholars appeal for dam safety assessments in geologically unstable south-west China [3]

One of the most glaring problems revealed by the disaster is that of dam safety. The Wenchuan earthquake has exposed three important issues regarding the construction of dams in southwest China:

• Whether it is appropriate to build big reservoirs and high dams in areas where there are seismic belts?



• Whether there is a possibility that mistakes were made in the assessment of seismic intensities during the planning stages of the dam?


• Whether the construction of big reservoirs and high dams in fault belts could trigger powerful earthquakes?

We hope that the relevant government departments will give serious consideration to these questions.

Dam safety is one of the most serious problems exposed by this disaster. In the fifteenth news conference on May 25, the deputy minister of Water Resources revealed that 2,380 reservoirs throughout eight provinces and cities including Sichuan, Chongqing and Shaanxi had been placed in danger because of the earthquake. The main problems included: dam cracking, dam sliding, destroyed spillways, collapsed outlets, breakwater walls broken, collapsed reservoir embankments, and so on. In Sichuan province alone, 69 dams are in danger of collapse, 310 have been deemed high risk, and 1,424 pose a moderate risk.

The damage resulting from the earthquake itself has been extensive, but if anything were to go wrong with the dams and reservoirs as a result of the earthquake, the whole area downstream would be inundated, and the casualties and property loss would be greater than those caused by the earthquake itself.

Now, apart from investigating the damage to dams and ensuring their safety, which is a little like mending the fold after the sheep have escaped, it is imperative to re-examine the plans to develop water resources in an unprecedented scale in the southwest region of China. The Wenchuan earthquake has highlighted three very important questions about dam construction in the southwest of China, all of which merit serious consideration.

1. Whether it is appropriate to build big reservoirs and high dams in areas where there are geological fault belts?

The southwest of China is geologically complex and affected by movement of the tectonic plates, especially on the eastern edge of the Qinghai-Tibetan Plateau bordering on Sichuan and the mountains and gorges in the northwest of Yunnan, which are products of the violent lifting and splitting of the earth’s crust. Areas such as this contain the most abundant water resources in China and have become the most important hydroelectric generating areas. Of the 13 hydropower development zones1 in China’s planned hydro-electricity generation program, the three most important are the Jinsha River, Yalong River and Dadu River zones, which are in western Sichuan and northwest of Yunnan. The zones on the upper reaches of the Yangtze River, as well as the Nanpan River and Hongshui River hydroelectric zones all straddle the provinces of Sichuan and Yunnan, and the Lancang River and Nu River hydroelectric zones are in the northwest part of Yunnan. (See Figure 1: Map of Yunnan Seismic Faults and Dam locations on The Lancang-Maekong)

Consider also that both Sichuan and Yunnan are the two provinces where the most earthquakes have occurred in China. They are part of the Sichuan-Yunnan earthquake zone of the north-south earthquake belts, where the magnitude and frequency of earthquakes in China is highest. Many of the cascade of hydro dams already built or planned to be built in the southwest will be built in earthquake zones. For example, the cascade of hydropower plants in the upper reaches of the Min River are located in the Songfan and Longmenshan seismic belts; the cascade of dams on the Dadu River (tributary of the Yangtze) have been and will be built in the Xianshuihe seismic belt; the cascade of dams built on the Yalong River (tributary of the Yangtze) are very close to the Anninghe-Zemuhe seismic belt; the Xiluodu dam on the Jinsha River (main channel of the upper Yangtze) is being built in the Yongshan seismic belt, and the dam projects proposed in the Lancang-Mekong and Nu rivers are located in the Three Parallel Rivers tectonic active belt.

The southwest area of China is geologically fragile and mud-rock-flows and landslides are common. Building a series of big reservoirs and high dams with a height over 100 metres -- and even over 300 metres -- is dangerous. Destruction of the rock mass along the reservoir is likely to occur as a result of large scale excavations of embankment slopes and large scale construction of highways and tunnels after the reservoir is filled. In the event of a strong earthquake, the above activities would exaggerate landslides, mud-rock-flows and landmass collapses, and even result in secondary disasters such as severe flooding or collapses caused by earthquake lakes. Thus we have to pay more serious attention to the hidden troubles and risks created for people living along the banks of rivers.