When water begins flowing through that pipe on Friday, WSA will start saving 6 million gallons of water each day, valuable savings during a drought.
The story of this pipe, known technically as a “flow augmentation line,” dates back four years.
During the record 2007 drought, WSA lost about half the water in its Dog River reservoir and had to purchase more than 60 percent of its water from the Cobb-Marietta system.
Since then, WSA has launched a massive reservoir and water treatment plant expansion to make sure such shortages won’t occur in the future, no matter how severe the drought becomes.
The first step was a $13 million reservoir expansion that raised the dam 10 feet and increased the lake’s capacity from 1.2 to 1.9 billion gallons. It was put in place nearly two years ago.
The second step, a $41 million water plant expansion, is nearing completion this fall and will boost the plant’s treatment capacity from 16 to 23 million gallons per day.
WSA also approved a $9.1 million water line project to increase the amount of raw water carried from the reservoir to the treatment plant.
“When we started the reservoir expansion, we were told by the U.S. Army Corps of Engineers that we would have to release about six million gallons of water daily from the dam to meet the minimum flow requirements in the stream below the dam to support aquatic life,” Mike Patton, WSA deputy director, said Wednesday.
Patton said the 900-foot stream segment runs between the dam and the Chattahoochee River and is the home of numerous species of wildlife.
Patton said Pete Frost, WSA executive director, came up with a brilliant idea to meet these flow requirements without having to use valuable reservoir water.
WSA had just completed a state-of-the-art wastewater treatment plant on Fouts Mill Road, about three miles from the dam. The effluent, the treated water that flows from that plant, is almost the purity of drinking water, Patton said.
“Why not use this water to satisfy the stream flow requirements?” was the question Frost asked.
The idea won approval of the Corps of Engineers, the Georgia Environmental Protection Division (EPD) and the Fish and Wildlife Service.
The result was the $3.6 million project which carries the wastewater plant effluent through 3.2 miles of pipe and into the stream below the dam,
“This means we’ll now be able to keep those six million gallons daily, nearly 180 million gallons a month, in the reservoir to serve our customers,” Patton said. “This is a tremendous value to us during drought periods like we’re now having.”
Astra Grading Pipe, LLC, of Woodstock, Ga., won the bid and began work in April.
“They had a completion date of Oct. 31, so they’re more than a month ahead of schedule,” Patton said. He said testing of the line would be done today, and if everything passes, water could begin flowing Friday.
He emphasized that the effluent water poses no danger to the stream marine life.
“It’s actually better quality than the water already in the stream,” he said. “It’s not quite the quality of drinking water, but it’s not far from it.”