New technology allows TVA to inspect dams faster, cheaper [photos]

Safety engineers using sonar scanning equipment that displays three-dimensional rendering

Benjamin Phillips, a dam safety inspector with the Tennessee Valley Authority, uses TVA's new 3D scanning sonar technology to perform a dam inspection at Chickamauga Dam Thursday, Nov. 16, 2017, in Chattanooga, Tenn. TVA can more quickly and efficiently inspect dams with the sonar equipment.

Technological advances are making Tennessee Valley Authority dam inspections cheaper and much quicker.

New sonar equipment is being used in place of divers with video equipment and has cut inspection time for each dam down from about a week to a matter of hours. The technology, called Side Scan Sonar, is a combination of instruments attached to the side of a 22-foot boat that feeds data to a monitor.

"It's an amazing tool to be able to look underneath the water and not have the limitations that you traditionally have with a video system," civil engineer and dam safety inspector Benjamin Phillips said. "We're now able to get a better view of what's going on in our facilities."

Previously, divers inspected dams several feet at a time. Now, civil engineers sit in the boat monitoring a screen feeding the data. That information then is displayed as a colorful, three-dimensional on-screen rendering at the end of the inspection. It is then further analyzed and compared over time with other inspections. The team also prints out the readings for future use.

Teams, usually consisting of two TVA civil engineers, work in tandem to use the sonar system to perform routine inspections on 49 area dams. Since TVA purchased the technology last year, they've inspected roughly half of those.

The new equipment not only saves time and money but allows dam inspectors to get a more thorough look at the dams, said Wesley Jaynes, a civil engineer and dam inspector.

Inspectors look for things such as cracks or trash that has found its way inside the dams' intakes. Material used in the making of the dams also causes the concrete to expand. TVA engineers are now able to use the data to track how much the concrete grows and moves over time.

"This is extremely valuable," manager of dam safety inspection Scott Kramer said. "We're seeing areas of the dams we've never seen before, at least not easily. With these inspections we're really trying to see if the dams are in good shape, so we're trying to identify any problems before they happen and become a serious issue."

The system will be used to inspect each dam at least once every five years. That data will then be compared to see how the dams have changed over time.

Phillips also said the program could provide good internship opportunities for area students. The controls are similar to playing a video game, he said, and students interested in STEM subjects could help with the inspections to gain experience and learn about the process.

Contact staff writer Mark Pace at or 423-757-6659. Follow him on Twitter @themarkpace and on Facebook at ChattanoogaOutdoorsTFP.