China officials insist Three Gorges Dam is safe, as online rumours of collapse rise

Writing on its official website, safety experts with the government-run China Three Gorges Corporation said that the Yangtze River dam had moved a few millimetres due to temperature and water level changes, but safety indicators remained well within their normal range.

It has been widely discussed on social media that the dam has become 'distorted', after a Twitter user posted satellite photos from Google Maps purporting to show the dam had bent and was at risk of breaking.

The dam’s operators are insisting that such distortions, detailed in the satellite images, are normal and that safety has not been compromised.

“With distortions, the dam body is in an elastic state,” the China Three Gorges Corporation said. “All data are within the design limits. All structures are operating normally and the project is operating safely and reliably.”

The central government has said the problem is with the satellite imaging, rather than the dam, according to a statement reported by the Caixin financial news service.

Fan Xiao, a Chinese geologist and long-standing critic of giant dam projects, said the rumours reflected the lack of debate about the Three Gorges project, which was now considered a "national treasure" that should not be criticised.

"If talking about problems is stigmatised, then it is nothing more than putting one's head in the sand and deceiving oneself," Fan posted on his WeChat account on Monday. "It will solve no problems and could make them worse."

The Three Gorges Dam was created to serve three primary purposes: flood control for the millions of people living downstream, including the cities of Wuhan, Nanjing and Shanghai; hydroelectric power production, generating approximately 22,500MW from 32 main turbines, and navigation improvement along the Yangtze River, enabling a sharp rise in the number of cargo ships and tourist cruise ferries.

Begun in 1993 and eventually completed in 2009, the 185-metre wide dam has proved to be one of China's most expensive and controversial engineering projects, permanently submerging entire cities, towns and villages, displacing millions of people and disrupting wildlife ecosystems, including in all probability causing the extinction of the baiji Yangtze river dolphin, as well as posing an ongoing serious threat to the critically endangered Siberian crane.

Critics of the huge engineering project also say that it has increased earthquake and landslide risks in the region. In the first four months of 2010 alone, 97 significant landslides were recorded.

In 2011, China admitted that the project had caused widespread social and environmental damage and promised 124 billion yuan ($18 billion) in extra funding for those affected. However, earlier this year, a Chinese parliamentary delegate said that half of the promised money had still not been paid out.

The Three Gorges Dam is so vast that in 2010 NASA scientists calculated that the shift of water mass stored by the dam complex would increase the length of the Earth's day by 0.06 microseconds and make the Earth slightly more round in the middle and flat on the poles.