Hall County is fine-tuning its plans to resubmit the official application for the Glades Reservoir in northeastern Hall County.
“We’re trying to shoot for the next 60 days to wrap this up,” Hall County Public Works Director Ken Rearden said.
The U.S. Army Corps of Engineers has given the county an indefinite extension to rework its reservoir application. That follows U.S. District Court Judge Paul Magnuson’s game-changing ruling last July that Lake Lanier was not a federally authorized source of drinking water for metro Atlanta.
Since the ruling, the reservoir project has shifted from a pool that would provide Hall County with a little more than 6 million gallons a day to a regional project that could yield up to 100 million gallons a day.
Forsyth County has agreed to buy capacity in the reservoir and Hall is hoping to get commitments from other metro counties, including DeKalb and Gwinnett.
Hall County plans to expand the project by pumping water from the Chattahoochee River to increase the reservoir’s capacity.
Rearden said a large intake pump would be installed north of Belton Bridge Road above the Corps of Engineers’ jurisdiction to help fill the reservoir.
“These are going to be huge pumps,” Rearden said.
Originally, the county planned to fill the reservoir by damming Flat Creek. Adding water from the Chattahoochee would increase the capacity more than tenfold.
“We’ll still capture some flow from Flat Creek for the Glades Reservoir,” Rearden said.
This type of reservoir is known as a pump storage reservoir, said Clay Burdette, program manager for the water withdrawal permitting program at the Georgia Environmental Protection Division.
Burdette recommends pump storage reservoirs, which he said are common around the state.
“We’ve been asking folks to look at this for years,” Burdette said. “Pump storage is a very good way to utilize the resources and keep the cost down as far as the size of the reservoir you would need, and it helps environmentally.”
In general, water is only pumped out of a larger river to fill a reservoir when the river is very full.
“You’re only going to pump it when the reservoir needs it,” Burdette said. “There’s times during low flows they wouldn’t be able to pump, and there’d be times when the reservoir was full they wouldn’t need to pump.”
Burdette said he could not speak to the specifics of the Glades Reservoir because Hall County has not yet submitted its water withdrawal permit.
“They’re all unique. We don’t have anything to officially look at and review,” Burdette said.
Rearden said there is plenty of depth to the Glades Farm property that makes it easy to add water to the reservoir.
“It’s mountains up there,” Rearden said. “It’s really steep terrain.”
The 850-acre Glades Reservoir is planned for a full pool elevation of 1,180 feet. In comparison, Lake Lanier’s full pool is 1,071 feet.
“It’s a perfect spot for a reservoir,” Rearden said. “We think we’ve got a jewel here.”
Due to limitations from the ruling, the county will not be able to use gravity to send water through from the Glades Reservoir down the Chattahoochee River through Lake Lanier, as originally intended.
Instead, the county will likely build a series of large pipes to carry water between the Glades Reservoir, the existing Cedar Creek Reservoir in East Hall, treatment plants and other counties.
“We’re talking about Cedar Creek being our stilling well to supply all this vast quantities of water to various entities down stream,” Rearden said. “We would use Glades as the holding basin.”
That would leave Glades full most of the time.
“We think that Glades will be able to stay up at the primary level unless we have a drought,” Rearden said.
Once it is complete, Glades Reservoir will be managed by Hall County instead of the corps.
Todd Rasmussen, a professor of hydrology and water resources at the University of Georgia, said as communities begin to build reservoirs, it will be important to look past construction.
“There’s one thing to build a lake,” Rasmussen said. “Another is to manage it.”
Rasmussen said unfortunately, some reservoirs lose capacity over the years as sediments build on the bottom.
But Rearden said Hall County is already working to combat the sediment problem by investing in screens and other guards that will keep the majority of solids out.
“We are designing all of our pump stations to avoid that as much as possible,” Rearden said.
The natural depth of the land will also keep sediment from causing too many problems.
“This reservoir is going to be 130 feet deep at the dam,” Rearden said. “It’s not a shallow lake.”
Rasmussen said reservoir construction is a start, but the eventual political, economical and regulatory solution to Georgia’s water supply worries is far from over.
“To come up with a solution that satisfies everyone, holy moley, it’s not an easy one,” Rasmussen said. “It’s not going to be something that goes away soon.”