TVA is using a new method for cutting a thin slice out of Chickamauga Dam to relieve stress from concrete growth. This allows spill gates and other plant equipment to continue to operate effectively.
A small amount of water will be seen spraying or streaming from the cut. Stability and safety of the dam is not affected.
This maintenance has been done before at Chickamauga in 1997 and 2008 to relieve concrete stress in the 80 year-old dam due to alkali-aggregate reaction causing concrete growth. This year, TVA is using a new slot-cutting method that requires no seal during the cut. It is safer, more efficient, and saves both time and money, said officials.
In the weeks ahead, it will result in a temporary stream or spray of water from the dam that may be visible to the public on the downstream face of the dam, along the north wall of the powerhouse. The largest amount of spray will be visible by mid-December. A new seal will be placed in the dam to stop the flow after the slot cut is completed in early 2021, pending weather conditions.
TVA also installed monitoring equipment that tracks what’s happening with the concrete. Approximately 200 automated instruments monitor the spillway on an hourly basis. Readings are evaluated on a monthly basis.
TVA invests in its dams through maintenance, inspections and upgrades to ensure continued flood protection of people and property during extreme events. TVA has invested more than $400 million in dam safety projects since 2010.