China's Three Gorges dam on alert
The massive dam project, built at a cost of $25bn, is supposed to help control China's annual flooding. But it continues to be highly controversial, even though China desperately needs the power it is designed to generate, says the BBC's Francis Markus in Shanghai. According to Ute Collier, the dams initiative leader for the World Wildlife Fund, the main danger concerns people living below the dam. As water fills the reservoir from the swollen rivers above, the level has to be reduced by releasing extra water downstream to alleviate pressure on the walls of the dam. "This could become a serious problem if the rains continue," Ms Collier told BBC News Online. Villages in Hubei province, downstream on the Yangtze River, are said to be braced for a possible surge in water levels. Ms Collier says part of the reason China suffers such acute flooding on the Yangtze is because huge areas of land have been deforested, leading to run-off water filling the rivers, which are then unable to cope when there is heavy rainfall. "There needs to be an effort to allow natural flood plains to do their work," she said. "Artificial dams have trouble dealing with extreme events like this."