U.S. Army Corps of Engineers Nashville District and Bauer Group management and personnel pose for photos on a specialty drilling rig during a ceremony to begin construction of a subsurface concrete wall as a barrier for potentially harmful seepage water moving beneath the earthen dam.

The first bite of a $106 million drilling project to stabilize the earthen portion of the Center Hill Dam with a barrier wall recently was taken by the U.S. Army Corps of Engineers Nashville District and its contractor, Bauer Foundation Corp., as the auger of a giant drill rig turned up the first dirt to the cheers of spectators.

The milestone event was made possible by the hard work of many people involved over the years in investigations, design and construction, according to project manager Linda Adcock.

“Building a barrier wall in the earthen embankment is the main protective feature in the Center Hill Dam Seepage Rehabilitation project,” says Adcock. “Bauer will drill down 300 feet from the top of the dam into 130 feet of rock and construct concrete columns to form this barrier over the next two years.”

Thomas Bauer, chief executive officer for Bauer Group, and Lt. Col. James DeLapp, U.S. Army Corps of Engineers Nashville District commander, are seen in front of the drill that made the first excavation in the earthen portion of Center Hill Dam to install a concrete barrier wall.

Quality control is paramount because the excavated columns must overlap to form a continuous barrier, according to Lt. Col. James DeLapp, Nashville District commander. “Bauer Foundation Corporation was selected for this contract because of its experience, technical capabilities, quality control and environmental measures,” he says. “We are dedicated to a partnership with Bauer to successfully complete this wall.”

One lane of Highway 96 will be closed for the next two years, and an automated traffic-control system will safely manage vehicles across the dam.

“The equipment that the public will see on the dam is to support, guide and operate the cutting tools working deep beneath the surface,” says Bjoern Hoffman, project manager for Bauer Foundation Corp.

Total cost of the project is estimated at $295 million, with about $140 million spent to date on investigations, design and construction. The Corps manages Center Hill Lake levels targeting a summer high of 630 feet above mean sea level and a winter pool of about 620 feet; however, day-to-day lake levels are highly dependent on weather. These target elevations are 10 feet to 15 feet lower than normal, and are part of risk management until repairs are complete in 2015.  ND