The coffer dam at the Three Gorges dam site on the Yangtze river in China, has been demolished in preparation for the impounding of water at the main dam. A series of 555 explosions was used to demolish the structure over 18 seconds. The coffer dam was built in 1997, just 300m from the Three Gorges dam. The cofferdam, founded on the main riverbed, allowed the second phase of the Three Gorges project to proceed. According to the construction plan, the first electricity generator is expected to be on line by 2003.