Lake Oconee’s New Oxygen System Scheduled To Be Operational In August

Georgia Power recently installed this liquid oxygen storage facility at Lake Oconee near Wallace Dam. Designers built the facility in a wooded area a few hundred yards from the shoreline to preserve the natural aesthetic of the lake.

Over the years, Lake Oconee has earned a reputation as a fantastic lake for striped bass and hybrid bass fishing, and its credentials as a productive bass and crappie lake are nothing to sneeze at. With a major new Georgia Power project at Wallace Dam about to go operational, anglers will have an additional reason to love the lake. Georgia Power and Southern Company have installed an oxygen diffusion system at Wallace Dam, and if supply-chain trouble doesn’t disrupt the testing schedule set for this month, the system will be operational sometime in August. 

Experts say the project will improve water quality at lakes Oconee and Sinclair and enhance striped and hybrid striped bass fisheries on the lakes.

A Georgia Power Project Many Years In The Making 

Lake Oconee’s oxygen diffusion system has been in the works for about five years. The project was part of a Federal Energy Regulation Commission (FERC) licensing proposal Georgia Power filed for Wallace Dam back in 2018. The FERC license was approved in 2020, and construction of the O2 diffusion system began at the dam in 2021.

Installation was completed last month.

The diffusion system at Wallace Dam is a cutting-edge solution to a persistent problem for water quality management in southern states: Low dissolved oxygen levels in the deep water of large lakes during the summer. 

Wallace’s system will be put through its paces this month in a series of tests that project engineers will use to determine how much oxygen operators should release into the lake during different temperature and flow conditions.

The tests could have begun sooner, but a nationwide diversion of liquid oxygen to medical facilities due to the pandemic meant that Lake Oconee’s O2 tanks sat empty for about two months. But the diversion has ended, and the tanks are now full.

Yet the team responsible for getting the project up and going must clear one final supply-chain hurtle before testing can begin. Some important O2 monitoring parts have not yet arrived, and they are essential to the tests. 

“The devices must be installed to provide a feedback loop when we do the testing,” said Courtenay O’Mara, an engineer at Southern Company. “We need to know how much oxygen we’re putting into the system versus how much the devices are measuring in the water.” 

These two data points, basically an input value and an output value, tell operators how the system is functioning. Information gleaned from the tests will allow operators to release the correct amount of oxygen into the lake, thereby maximizing the benefits of the diffusion system. 

Barring further delay, testing at Wallace Dam should begin soon, and the new oxygen diffusion system should be operational sometime in August.

An Improvement To The Fishery

Tony Dodd, an aquatic biologist at Georgia Power, said the system will benefit anglers by increasing dissolved oxygen levels in parts of Oconee and Sinclair lakes that currently experience oxygen depletion in the summer.

“In the summertime, almost all deep lakes (in the Southeast) have depressed oxygen levels in their deeper layers,” Dodd said. “And by having this system in place, we can provide a stream of oxygen that effervesces into the water column, increasing the dissolved oxygen levels of those deeper layers of the lake. This system will be seen as an enhancement to the fishery,” he said.  “In the summer months when our deep lakes are stressed, striped bass and hybrid striped bass are always seeking suitable habitat, and this new oxygen diffusion system provides a broader range of suitable habitat in the lake.” 

And that’s good news for fishermen.

This design drawing of Lake Oconee’s oxygen diffusion system was part of the relicensing proposal for Wallace Dam submitted by Georgia Power to FERC in 2018. The picture shows the location of oxygen diffusion lines that have been sunk into the lake. The lines enter Lake Oconee from a small, forested point on the lake’s eastern shore about 250 yards north of Wallace Dam, and then run northwest along the channel bottom. In the picture, the sections of the diffusion lines that release oxygen into the lake are shown in red.

How It Works 

Oxygen diffusion systems work much like the bubbler one might find in a home aquarium, but instead of releasing air, O2 diffusion systems release pure oxygen into the deep, oxygen poor, waters of lakes.

At Wallace Dam, liquid oxygen is stored in tanks that can be refilled as needed. When the system is in operation, the oxygen is very cold as it leaves the tanks, so the oxygen—now a gas—is heated before it enters a system of perforated lines, called diffusers, that release the oxygen into the water. The diffusion lines are several hundred feet long, and sunk deep in the lake. They extend from the forebay of Wallace Dam, upstream, deep into the reservoir.

Oxygen is released into the lake in two concentrations. “One part of the system is designed to put out a low level of dissolved oxygen 24 hours per day during the critical season for low dissolved oxygen,” O’Mara said. “The other part consists of booster lines that release higher levels of dissolved oxygen right before we start to generate.”

If past successes with oxygen diffusion systems in Georgia have any predictive value, the new Georgia Power O2 diffusion system will usher in a new era of abundance for Lake Oconee’s striped and hybrid striped bass fisheries. It’s all good news.