Close windowGlossary
Cofferdam - A temporary structure that is used to create a dry enclosure in a body of water such as a river, lake or sea. Water is pumped out of the enclosure so that a permanent structure, such as a bridge pier or dam, can be built below the water level.
This picture shows the second stage of construction for the
Three Gorges dam in China. The upstream
and downstream cofferdams
are embankment dams
made from rockfill and the
longitudinal cofferdam is constructed from concrete