Atlanta builds a giant underground flood defense
In the aftermath of Intense rainfall that triggered flash flooding and snarled rush-hour traffic on interstates in Atlanta this week, the Georgia Department of Transportation was busy cleaning up to restore normal traffic flow and preparing for, potentially, more rain.
In a statement to CBS News Atlanta, GDOT said, "There is a limit to how much rainfall any drainage system can take and this is exacerbated by recent drought conditions, which make things prime for flooding."
Meanwhile, the City of Atlanta has undertaken its own flood mitigation project, now more than a year in the making.
The $160 million project, known as the Custer Avenue Multi-Benefit Capacity Relief Project, has been under construction in the Summerhill neighborhood and is expected to be completed in 2027.
At the center of the effort is a massive underground storage facility capable of holding 20 million gallons of stormwater and wastewater during major rain events, roughly the equivalent of 30 Olympic-size swimming pools.
The project is part of a broader plan by the City of Atlanta Department of Watershed Management to improve surface water management across the city through a series of underground storage vaults designed to temporarily capture and release high stormwater flows during intense storms.
Officials say the goal is simple: reduce pressure on aging sewer infrastructure before it becomes overwhelmed.
"When you have these intense storms, like what we just experienced, what it does is it takes that peak flow that overwhelms the pipes," said Sharon Matthews, project manager with Santec Consulting, a contractor on the project for the city. "It spreads the flow out, allows it to be held, and then it releases itself back into the system as capacity becomes available."
Deputy Commissioner Quinton Fletcher of Atlanta's Office of Water Treatment and Reclamation called the project a major investment in the city's long-term storm planning.
"This project represents resiliency," Fletcher said. "This is one of the projects that the Department of Watershed Management is undertaking to deal with flooding."
The construction site, a massive city block of exposed pipe and concrete, is currently underway, but once completed, officials say the site will look far different from a traditional municipal infrastructure project. "It will be a beautiful green space, a park, for the entire community to enjoy," said Matthews.
City officials say the finished 5-acre park will sit atop the underground storage system, meaning many visitors may never realize the critical infrastructure the site will provide.
"If you didn't know it," Fletcher said, "you would have no idea what job it was doing right under your feet."