Earthen Cofferdam
Earthen cofferdams are constructed at the place where the height of the water is less say 3m and the current velocity is low. These dams are built using the local available material such as clay, fine sand or even soil.
The height of the dam is kept 1m more than that of max water level. Freeboard of the dam or the top of the dam is kept 1m so that the water doesn’t enter the other side even when waves arise.
The slope is usually given but 1:1 or 1:2. The slope of the water side is pitched with rubble stones so the water action doesn’t score the embankment. Even sheet piles are driven in the center of the dam to resist water seepage. After the construction of earthen cofferdam, the water from the other site is pumped out and construction is executed.
