THE last cofferdam built during the construction of the Three Gorges Dam was demolished through explosion in 13 seconds at 4pm.

Engineers used 191.3 tons of explosives and 2,534 detonators to accomplish the underwater blast to smash the 180,000 cubic meters of concrete.

The 15th block didn't fall into the water. But technology experts said it won't influence the result. They will take down it by another minor underwater explosion.

The shipping brakes in the Three Gorges resumed working and the maritime authority will lift the traffic halt.

The cofferdam, with its southern connection section joining the main dam, measures 580 meters long, 140 meters in maximum height and 8 meters wide at top.

The cofferdam has been holding the reservoir water since 2003, while workers were building the dam.

The removal of the cofferdam means the Three Gorges Dam, completed on May 20, will formally begin its role in flood control two years ahead of the schedule.

The China Three Gorges Project Corporation said last month that the dam would help prevent flooding on the middle and lower reaches of the Yangtze River, along with supplying China with much-needed electricity.

The 185-meter-high dam will be capable of holding 22.15 billion cubic meters of water. Its level will be maintained at 175 meters at most times when the project is fully completed by the end of 2008.

--- source: ShanghaiDaily