TENNESSEE VALLEY AUTHORITY
Bubbles and Breakthroughs: Guntersville Team's Innovation Helps Clear Eelgrass and Debris

Sometimes, ideas strike us in the unlikeliest of places. In this case, it was underwater.

This particular stroke of genius occurred when a maintenance diver at Guntersville Dam recently made an innovative discovery, said Slade Miller, Hydro Technician IV.

The diver was originally cutting matted eel grass along the trash rack of the hydro intake, but then something incredible happened.

"The diver had an idea," Miller said. "They held their breather hose under the rack and noticed that the grass began to release. The bubbles were creating a sort of barrier."

No sooner had the diver surfaced than the plant crew, alongside their Regional Engineering Team, put their heads together to build a full-scale solution. They tested the idea. It worked again.

Guntersville Dam plant manager Mike Adams explains how the bubbler system works. 

That simple observation became the basis for a mechanical system the plant engineered from scratch and tested on Guntersville's Unit 1. The team is now installing it permanently, with the system scheduled for a fully engineered installation in June.

The system's technical name is a sparger, although the crew affectionally named it the bubbler. It's a horizontal pipe system mounted directly on the bottom of the trash rack. Air pressure is fed into a perforated pipe header, with the air escaping the small holes to send up a curtain of bubbles that lifts and releases the grass on the racks. Once freed, the vegetation moves away from the trash rack and is spilled downstream.

Plant manager Mike Adams said the first trial exceeded his expectations.

"It worked a lot better than expected," he said, excited about this in-house invention. "On our first test, it removed a lot of debris - even a tire and a tree from the trash rack."

The team at Guntersville Dam knows just how vital the water is to the city and its tourism. Boasting a 69,000-acre water playground, Guntersville lake is a thriving asset for the surrounding community, attracting over 300,000 visitors last year.

Because TVA's teams work to make this region a wonderful place to live, work and play, ingenuity must happen inside the boundaries of the mission. And the team at Guntersville Dam proved they're up for the challenges.

"This is an original thing for TVA," Miller said, proud of this long-awaited breakthrough for Guntersville. "And I'm proud to be part of it."