China's media is aflutter with questions about just how big a flood the mighty Three Gorges Dam was designed to withstand.
Is it designed to withstand a) 'the worst flood in 10,000 years,' as officials claimed in 2003; b) the worst flood in 1,000 years, as claimed in 2007; or c) the worst flood in 100 years, as said in 2008?
The question may be a bit tongue-in-cheek, but it relates to a serious discussion as flood-swollen Yangtze River continues to test the dam. Even China Daily, the state-run English-language newspaper, has weighed in on the debate, quoting Cao Guangjing, chairman of the China Three Gorges Corp, as saying in an interview that 'the dam's flood-control capacity is not unlimited.'
The discussion is important because one of the primary justifications for building the world's biggest dam was to control deadly seasonal flooding along the Yangtze. After the government approved construction, only a few dared publicly question the project.
So why are government censors now allowing this unusually frank talk? Partly, the debate reflects the assertiveness of China's increasingly free-wheeling media and online community. Since questions first arose about the dam triggering landslides in the geologically unstable region, Chinese media have been apparently allowed to challenge the once sacrosanct project.
Another reason could be that officials realize they need to play down the Three Gorges Dam. It's not the panacea it was once billed to be-even if it can effectively reduce some flooding. For example, the dam can't solve the problems caused by the loss of marshlands that acted as natural flood-zone buffers, nor restore soil erosion and deforestation that also contribute to floods.
Minimizing expectations ahead of time could reduce any backlash later.
Cao told China Daily that the dam can handle water flows up to 83,700 cubic meters per second, higher than 70,000 meters a second recorded during the peak earlier this week. He also notes that any dam has a maximum it can tolerate. 'Any flood with water flow exceeding 122,000 cubic meters per second would put the dam's own safety at risk,' he's quoted as saying.
So the question remains, could that happen a) once in 10,000 years b) once in 1,000 years or c) sooner?
ZUMApress.com三峡大坝的水力发电机组三峡大坝的防洪能力究竟如何？a) 2003年相关官员号称的“可抵御万年一遇洪水”，b) 2007年所称的“千年一遇洪水”，c) 2008年的说法──百年一遇的洪水？