US Army Corps of Engineers
Savannah District Website

Building the Coffer Dams

The first phase of the dam project was the construction of the navigation lock on the Georgia side of the Savannah River.  The coffer dams were built to redirect the river so workers could construct the lock and dam on a drier surface. Workers filled these temporary dams with granite, rock, and dirt to stop the river’s water.

Coffer dams are watertight enclosures that are constructed so workers can build on surfaces that are normally underwater.

After workers completed the lock, they opened it, and the river flooded the lock and rerouted through it. Workers then constructed another coffer dam on the South Carolina side of the river to build the pylons and lift gates of the dam.

These machines inside the coffer dam continually pumped water into the river to keep the construction area dry. This is the coffer dam on the South Carolina side of the river. The dam was built inside, 1935.
Workers flood the coffer dam, 1935.
Workers walk along the top of the lock coffer dam in 1935.
Pumps remove water from inside the coffer dam on the South Carolina side of the river, 1935.
The first completed coffer dam was located on the Georgia side of the river. Workers built the lock on the relatively dry ground inside this coffer dam, 1935.