CARTERS LAKE, Ga. – The U.S. Army Corps of Engineers, Mobile District, recently began maintenance operations at the Carters Lake Reregulation Dam in Murray County, Ga. to relieve stress on the structure caused by concrete expansion. The district first noticed the expansion almost 20 years ago.
“In 1999, project personnel noticed that one of the four spillway gates would not open all the way,” recalled Structural Engineer Matthew “Scott” Ellzey.
To mitigate the effects of expansion, the Nashville District will come in and cut a slot in the dam to relieve some of the stress. The Mobile District has prepared the site for the slot cutting operation, and currently, the Mobile District’s Subsurface Exploration Technical Center of Expertise is drilling core holes in the dam at four different locations. Once the drill work is complete, the Nashville District personnel will have the necessary access needed to perform the slot cut.
“This is the first project like this in our district,” said Project Engineer John Bass. “So we have been working with the Nashville District because they are subject matter experts in this area.”
“There are two types of holes that we are drilling in the dam,” explained Bass. “Two, ten inch holes that will stop approximately halfway through the structure so that we can feed the diamond bit rope through, and two 8 inch holes that will run the full height of the dam (over 80 feet) into the foundation to allow for the installation of water stops once the slot cuts are complete.”
The goal for the project is to relieve stress on the dam to allow the spillway gate to function correctly.
“Our goal is to at least temporarily relieve the stress on the dam that is causing issues with the end gates,” said Bass. “But we have also attached various instruments to the dam so that we can monitor any further expansion in the future.”
With multiple districts, agencies and contractors involved in the project, Ellzey took time to thank everyone involved in the planning process that has prepared the district to execute their current mission.
“The collaboration between different districts, civil authorities and contractors to come up with the design for this project has truly been amazing,” said Ellzey.
Maintenance operations on the dam are expected to wrap up by October with little, to no, impact on recreation, hydropower or water management operations at Carters Lake.
“There is a potential for the water being dropped a little bit in the re-regulation pool and a few roads and parking areas might be closed, but we are still working that out,” said Bass. “Our hope is to limit impacts to Carters Lake as much as possible.”
The Reregulation Dam was originally constructed in 1974 and is located approximately 25 miles below the mouth of the Coosawattee River. The dam stands 105 feet high and 3550 feet long.