In an era when budget cuts have diverted dollars from recreation, a $6 million project to improve fishing at Thurmond Lake is finally on the front burner.

Bids will be opened Nov. 15 for a cryogenic oxygen plant in McCormick County, from which 20 to 100 tons per day of liquid oxygen will be pumped through seven miles of submerged, perforated pipes.

The idea, according to spokesman Billy Birdwell of the Army Corps of Engineers, is to add oxygen to the lower lake during hot weather, when falling oxygen levels force fish to swim upstream.

Once the system is completed in 2010, it will boost dissolved oxygen by up to 3 parts per million along a five-mile path from Modoc, S.C., to Thurmond Dam, where oxygen levels can now fall to 1 part per million in warm weather.

Although the project will benefit fish -- and fishermen -- the oxygen system is part of a broader plan for wiser use of Thurmond Lake's often sparse water supplies and the ability to generate more electricity.

The corps promised to build the oxygen system in 2002 as part of a settlement to a 14-year-old lawsuit over Russell Dam's reversible hydropower turbines, which can pump water from Thurmond back into Lake Russell for reuse in power generation.

Since the turbines can cause fish kills, the corps agreed to add the oxygen system as part of its mitigation plan, which also includes restrictions on the use of the turbines.

"In the summertime, when water quality goes down, naturally we can't use all four pumpbacks all the time because it lowers water quality," Mr. Birdwell said.

"Right now we restrict it to two pumps, but once we put the system in, it will improve water quality and it will allow us to use all four pumpbacks year-round," he said.

He added, however, that a restriction during May, when fish are spawning, will remain in effect.

Although the ability to reuse water for power generation will create more electricity, Mr. Birdwell said it will do little to raise lake levels during drought.

"Even though it gives us a lot of capability to generate more electricity, we're required to send 3,600 cubic feet per second downstream (in the Savannah River) regardless," he said. "So while it doesn't really conserve water, it allows us to use the same water multiple times and we get more electricity."

Chris Martin, the regional fisheries supervisor for Georgia's Wildlife Resources Division, said the project will create the most benefit for striped bass and their primary prey: blueback herring.

"These are fish that like deeper, cooler water in the summer months," he said. "A project this large would create a very large refuge of well oxygenated, cool water."

The system also is likely to have effects downstream in the Savannah River below the dam, he said. "If you have liquid oxygen in that zone upstream, the water released from the dam will have more oxygen for fish below the dam, which should improve fishing there, too."

Mr. Birdwell said the project will commence with about $2 million in improvements at the plant site on Gilchrist Ferry Road near Modoc, followed by the construction of the oxygen plant itself.

Liquid oxygen will arrive by tanker truck during its months of operation, expected to be roughly June through September.

Currently, he said, three of Russell's four reversible units are shut down for maintenance or repairs and will resume operation this fall.

Reach Rob Pavey at 868-1222, ext. 119 or rob.pavey@augustachronicle.com.