https://dcist.com/story/21/04/27/dc-water-finishes-digging-tunnel-stop-flooding-sewage-overflow-anacostia-river/



Chris has been underground since 2018, diligently digging, starting at RFK Stadium and slowly moving northwest. Now, Chris’s work is complete — a 5-mile long, 23-ft. wide tunnel that will soon prevent sewage overflows into the Anacostia River and stop flooding in low-lying neighborhoods, including Le Droit Park and Bloomingdale.

Chris is a massive tunnel boring machine, longer than a football field, that simultaneously digs the tunnel and constructs its concrete walls, all 100 feet below ground. The tunnel runs underneath Metro’s tunnels (and everything else humans have built underground) and is wider than a Metro tunnel, too.

“It’s amazing accomplishment,” says Carlton Ray, vice president of DC Water’s Clean Rivers Project. The project aims to build 18 miles of such tunnels, capturing sewage overflow that would otherwise flow into the Anacostia, the Potomac, and Rock Creek. This sewage overflow is a result of D.C.’s antiquated sewer system, and one of the major reasons the city’s water bodies are too polluted to swim or fish in.

“The federal government left D.C. this undersized sewer system that basically when it rains, we have raw sewage or combined sewage overflows into the river,” Ray says. “We’re capturing that that sewage and ultimately are going to make the Anacostia River fishable and swimmable.”