The Three Gorges Dam finally reached full power output in July, but geological risks are forcing some 120,000 people living along its reservoir to relocate, many for the second time. From Reuters’ Sui-Lee Wee:
Landslides in Huangtupo had been exacerbated by changes in water levels in the reservoir, said Fan Xiao, a geologist for a government-linked institute in southwestern Sichuan province, who studied conditions there in 2006.
Dam officials lower water levels by as much as 30 meters during the summer in anticipation of floods, and raise them in winter. The change softens the slopes along its banks, Fan said.
“It’s like a person who’s standing in place, if you push and pull him, he’ll definitely not be as stable as before,” he said.
[…] A shop owner, surnamed Qing, has been told she has to move in the second half of the year. She relocated the first time in 2000 when water from the reservoir flooded her home.
Asked if she thought the government would compensate her this time, she scoffed.
“The more we move, the poorer we get,” she said.
Despite this, officials claim that the dam has been a major boost for the local economy, accelerating development by as much as a century. Flood prevention, another of the dam’s major selling points, has also become a source of some scepticism according to Deng Quanlun at chinadialogue:
Since the Three Gorges reservoir was filled, there have been no repetitions of the severe flooding of 1998, which killed more than 3,700 people and left 15 million homeless. [… But] Informed sources say that local governments downstream of the dam have all asked the operators to release less water in order to reduce flood risks, meaning the dam is under pressure from both sides.
The dam has long faced such difficulties. Upstream, the city of Chongqing complains that the dam makes flood prevention more difficult – that “Chongqing drowns to save Wuhan”. Downstream, there are complaints that it continues to release water even when there are flood risks. Cai Qihua, head of the Yangtze River Commission, said this is a misunderstanding: when the dam holds back floodwaters, the reservoir level does rise, but this has little or no impact on Chongqing upstream. The rising waters in Chongqing are due to water coming from the Jin, Min and Jialing rivers, and water backing up at the Tongluo Gorge, downstream of Chongqing, Cai said.
The dam’s role in flood prevention is to control water coming from the upper reaches of the Yangtze. When it comes to regional flooding downstream, it can only play an indirect role. Weng Lida, formerly head of the Yangtze River Commission’s Water Resources Protection Bureau, explained that the dam can retain water from upstream, but if there is heavy rain downstream, there is nothing it can do. Nor can the dam store all of the floodwaters – it can only hold back those which cannot be safely released into the rivers downstream. “The flood prevention ability of the dam is limited – it can’t do everything,” said Weng.