Pickwick Dam Project Delivers Waves of Change

Safeguarding the Grid and Boaters

A five-year project recently completed at Pickwick Dam has modernized generating units to benefit the grid – but boaters need to be aware of new safety warnings resulting from the upgrades.

Despite posted warnings that instruct boaters to keep away from TVA dams, anglers will often pull their boats right up to the dams.

At Pickwick, one of TVA’s oldest dams, the new operational changes have the potential to impact boaters who do not steer clear of the dam.

Pickwick has undergone what’s known as an evacuation air project, which enables the site’s six generating units to operate in synchronous condensing mode. This means they can be used for grid voltage regulation when they are not generating power for more than 144,000 homes.

“The generators have essentially been turned into motors,” TVA turbine engineer Jeff Amos said. “They provide or absorb reactive power – or the power needed to keep electricity flowing across the grid and make the grid more stable, reliable and resilient.”

TVA engineers developed the intricate design standards for this project and successfully implemented them at Pickwick.

“This equipment dates back almost 100 years,” said Jamey Haddock, Pickwick Dam plant manager. “This project has upgraded it with modern components and controls.”

Evacuation air projects are planned for more than 80 units across TVA’s dam system over the next seven years.

“We learned a lot from this project,” Amos said. “It will be a blueprint for systemwide projects.”

These photos show how the new system at Pickwick Dam can create turbulence at the back side of the dam.

Steer Clear of Dam Dangers

When Pickwick’s units are in condensing mode, an air pocket develops around the turbine runner. When they are moved from condensing to generation mode, this air is released out the back side of the dam, causing turbulent waters. Pickwick produces stronger turbulence than other condensing units in TVA’s system because of the lower elevation of the turbines relative to the tailwater.

“Boats could be very vulnerable when this turbulence occurs,” Haddock said. “Even the most experienced boater with the strongest motor is no match for this turbulence.”

To alert boaters, four new warning signs were recently added on the downstream face of the dam, said Harrison Strickland, TVA’s Program Manager of Public Safety Around Dams.

Additional signage with new graphics is scheduled to be added across the site this year. Pickwick also has strobe lights and audible alarms to warn boaters to clear the area before spill operations begin or before units are turned on. Boaters must heed these warnings and leave the area immediately to avoid potentially deadly consequences.

“Boaters should exercise the utmost caution when recreating anywhere near the dam,” Strickland said. “They should obey all posted safety signage and pay close attention to the warning strobes and sirens. At the end of the day, it is truly best to just steer clear of the dam entirely. No fish is worth risking your life.”

This video demonstrates how the new system at Pickwick can create turbulence at the back side of the dam: