This is the coffer dam Dec. 5, 2017at the Chickamauga Lock Replacement Project where the U.S. Army Corps of Engineers Nashville District is overseeing the excavation and removal of 100,000 cubic yards of rock to make way for future concrete placements for a new lock chamber. The ongoing contract with Heeter Geotechnical Construction includes the installation of 44 rock anchors along the river wall of the coffer dam.