Photo Credit: Alex Mead
This is a coffer dam used in the construction of a bridge pier. Cofferdams like this one are used to create a dry area so construction can take place on infrastructure that is in the water. A careful eye will be able to see epoxy coated rebar in the bottom of this cofferdam, as well as the water being pumped out near the top right of the picture. Many times cofferdams are not watertight and require nearly continuous pumping.