Three Gorges Dam faces stiffest test yet
The massive Three Gorges Dam faces its biggest flood-control test after days of torrential rain created the sharpest surges on the upper Yangtze River for more than a decade.
A flood crest hitting a maximum volume of 70,000 cubic metres per second is expected to pass through the dam on Thursday, said a report released yesterday by the Yangtze River Water Resources Commission.
The peak is shaping up to become the biggest surge to hit the Yangtze since 1998, when flooding on the undammed river left 3,000 dead and 14 million homeless downstream.
Floodwaters poured into the Three Gorges Reservoir at up to 47,000 cubic metres a second yesterday and are expected to rise above 65,000 cubic metres a second between today and tomorrow. High water levels have already forced the closure of locks at the dam.
'The water level in the reservoir will continue to rise ... This is going to be the biggest challenge for the dam since its completion,' said the China Three Gorges Corporation.
Four sluice gates were opened yesterday to release water at 48,000 cubic metres a second. As a result, the dam's water level dropped to 146 metres, from 147 metres on Saturday, with more than 500 million cubic metres of floodwaters being discharged.
The maximum water level of the dam, the largest hydroelectric project in the world, is 175 metres. It reached 171 metres during a test run last year, but officials held off from raising the level to 175 metres in order to relieve areas downstream that were then suffering from a severe drought.
Lower reaches of the Yangtze were facing an 'extremely severe' flood situation, Liu Ning , deputy head of the Office of State Flood Control and Drought Relief Headquarters, told Xinhua. The report said mid-stream areas were holding up fine for the time being due to the dam's flood control.
Water levels at several big lakes downstream surged past their danger marks on Saturday as the meteorological centre said fresh downpours could further swell rivers flowing into the lakes. Poyang Lake in Jiangxi saw water levels 70 centimetres above its alert mark. At Dongting Lake, in Hunan , the water was seven centimetres above danger level.
The Three Gorges Dam, costing 180 billion yuan (HK$206 billion), was finished in May 2006 and went into full operation last September. It is 2,335 metres long and 185 metres high. The project, aimed at generating electricity to power the economy and prevent flooding downstream, drew fierce criticism for uprooting more than one million people.
The water level at the dam has reached 171 metres in tests. Its maximum is: 175m
