Building a massive stink-filled tunnel under DC, 6 feet at a time

DC Water continues to make progress on its Northeast Boundary Tunnel. Its largest and most ambitious project yet is meant to keep sewage and storm water runoff out of the Anacostia. So far, 7 miles of the Anacostia River Tunnel have already been built.

The new tunnel will add an additional 5 miles, running from underneath the area of Sixth and R streets Northwest in Shaw and up under Rhode Island Avenue before jutting down into Southeast.

After descending on an elevator from the southwest corner of RFK Stadium in Southeast D.C., a train takes workers through the first 7,000 feet of tunnel. Currently, the work is happening in an area below the meeting point of the Langston Golf Course and the National Arboretum — though it’s so far down below, you’d never know it’s happening.

“We’re mining and installing rings,” said DC Clean Rivers Director Carlton Ray.

Crews are using a football-field-sized piece of machinery that bores under the ground 6 feet at a time. After the dirt is funneled out, massive concrete panels 14 inches thick are installed. Together, seven of the panels, each weighing about 10,000 pounds, will form the next 6 feet of tunnel. Then, work begins on the the next 6 feet of the project.

“We average between 40 and 50 lineal feet a day,” said Ray, but on a great day they might go 150 lineal feet forward. How far they get is dependent on the varying types of dirt under the soil. Currently, the digging goes on 24 hours a day, usually six days a week.

“So far, that first leg of tunnels that we built, about 7 miles of tunnel, we’ve caught over 6 billion gallons” of sewage so far, said Day. That’s enough to fill Nationals Park with sewage 145 times.

“The tunnels run downhill the whole way from where they start to the Blue Plains,” he said.

Once it arrives there, Day said, “we recycle the water, and it comes out looking like Colorado mountain spring water.”

Northeast Boundary Tunnel digging
Crews are using a football-sized piece of machinery that bores under the ground 6 feet at a time. “We average between 40 and 50 lineal feet a day,” said DC Clean Rivers Director Carlton Ray. But on a great day, they might go 150 lineal feet forward. (WTOP/John Domen)
Northeast Boundary Tunnel project
After the dirt is funneled out, massive concrete panels 14 inches thick are installed. Together, seven of the panels, each weighing about 10,000 pounds, will form the next 6 feet of tunnel. (WTOP/John Domen )
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Northeast Boundary Tunnel digging
Northeast Boundary Tunnel project

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