|Temblor shakes China's big dam ambitions|
By Antoaneta Bezlova
DUJIANGYAN, Sichuan - China's deadly earthquake last month appears to have shifted more than just tectonic plates in the country's picturesque Sichuan province. The May 12 temblor has given a boost to China's green lobby, which has been calling for a review of Beijing's zealous dam-building program and may tilt the balance of public opinion in favor of such appeals.
When the quake struck, it came in an area famous for ancient hydrological works. Sichuan is the homeland of Da Yu, the legendary Chinese emperor who won his right to the throne in 21st century BCE (Before the Common, Christian Era)by controlling floods. Instead of building dikes as others did before him, Yu dredged out river channels to release the torrential waters. He then directed the water to irrigate distant farm lands.
Twenty centuries later, Yu's flood controlling technique was used in the hydraulic project of Dujiangyan. The ancient system - operational now for the past 2,000 years - has made the city of the same name a magnet for tourists and has won it recognition as a United Nations Educational, Scientific and Cultural Organization World Heritage Site.
While the city of Dujiangyan was almost entirely destroyed by the magnitude eight earthquake, the old hydraulic system located only 10 kilometers from the epicenter, survived the temblor with little damage. The same cannot be said about the cluster of 6,000 reservoirs and dams that local experts estimate have been built on the rivers of Sichuan.
"Such a strong earthquake would have an enormous influence on the dams in the whole area," says David Simpson, a US seismologist with the Incorporated Research Institutions for Seismology. "You are certain to have concerns if you build many dams in mountainous areas as is the case in Sichuan."
In the wake of the quake, which to date is estimated to have claimed about 70,000 lives, the rush and struggle to assess the damage done to Sichuan's hydropower works were featured less prominently by the media than the frenzy of rescue operations. But as provincial authorities brace for the surge of seasonal floods, the danger of dams bursting and creating a much bigger havoc than the earthquake has prompted Chinese experts and activists to raise their voices.
An open letter issued by a group of 40 academics and environmentalists on June 19 warned of more devastation if environmental and geological risks of damaged dams are disregarded. "The quake has highlighted the urgency to make a thorough investigation of damage to the dams, which would embrace another severe test of imminent floods,'' the petition said.
About 2,380 reservoirs and dams all over the country sustained damage from the quake, according to a Ministry of Water Resources survey last month. Some 69 were assessed to be on the verge of collapse. But experts say this is only an indication of the total risk.
Modern China did not follow the path of its ancient sages in using rivers' natural flows to control flooding and irrigate the land. The late communist chairman Mao Zedong decreed that China's new socialist man must conquer nature. In less than 60 years since the founding of communist China, the country managed to build some 87,000 reservoirs and dams.
Over 20,000 of these are significantly high to be considered large dams. Whether in terms of numbers or grandness of dam works, China now is the world's leader. It is home to the Three Gorges Dam, a hydroelectric power project on the Yangtze River which in the course of construction displayed more than 1 million people.
The country's leadership is not stopping here. More than 30 large dams are on the drawing boards of Chinese engineers awaiting approval and completion as the country scrambles to feed energy to its fast-growing economy.
Initial official statements after the quake indicated little wavering from Beijing's determination to press on with intensive hydropower development in the area.
"There will be risk assessments of future projects in China's southwest but I don't think the quake would lead to great changes in current plans," Liu Ning, chief engineer with the Ministry of Water Resources told the press soon after the earthquake.
Having harnessed major rivers and tributaries in the country's central and eastern parts, the attention of Chinese planners is now focused on developing the abundant water resources of western and southern provinces. But that water cache comes with a snag - the southwestern part of China is one of the most earthquake-prone zones in the country.
Three major fault lines traverse Sichuan, making it geologically unstable. Nevertheless many big dams had already been built in the area, such as those on the Min, Dadu, Jinsha and Yalu rivers. The Min, a tributary of the Yangtze that runs right through the earthquake zone, has not less than 29 reservoirs and dams.
What is more, Zipingpu, the Min river's largest dam sits only 5.5 kilometers from the epicenter of the earthquake. Fan Xiao, a geologist based in Sichuan, believes the construction of Zipingpu has contributed to the severity of the latest earthquake.
"There has never been such a strong earthquake in this area before," Fan says. "Our records show four earthquakes in the past of magnitude above six but never one stronger than this latest one. Zipingpu is the biggest dam on the Longmenshan fault line and it was filled sometime ago - in the end of 2006. We need to investigate the possibility that the dam was among the triggers of the quake."
Sichuan Seismological Bureau, which from the very beginning opposed the construction of the dam because of its proximity to the Longmenshan fault line, is now investigating the likelihood that the dam could have exacerbated the severity of the tremor. "We hope the results of the investigation will be made public," says Fan.
Four major earthquakes in the past are acknowledged to have been triggered by dams in their vicinities - in Koyna, India (1967), Kremasta, Greece (1965), in Kariba, Zimbabwe-Zambia (1961) and in Xinfengjiang, China (1962). China's quake measured 6.1 and damaged the Xinfengjiang power station in Guangdong to such extent that it led to its closure.
While Zipingpu in Sichuan was built to the highest quake-resistant standards, many other Chinese dams, particularly those designed and constructed during the Great Leap Forward (1958-1961) and in the 1960s are not. They are often referred to by experts here as "time bombs". A history of China's half-century of dam building, compiled by academic Pan Jiazheng, estimates there are 30,000 of these poorly built and obsolete structures all over the country.
The May 12 tremor caused the quake-proof Zipingpu Dam to sustain severe cracks and fractures on the sides but the damage done to other older and less quake-resistant dams is anybody's guess.
The open letter issued by China's green lobby appeals not just for thorough investigation into the quake damage but also for risk assessments of all hydropower projects planned for earthquake-prone Sichuan and Yunnan provinces. A series of 13 dams, many of them taller than the 150 meter-high Zipingpu, are projected to be built on the Nu River, in proximity to another major fault line near China's border with Myanmar and Laos.
(Inter Press Service.)