More than 100 feet under the Potomac River, scores of construction workers tend to Lady Bird, D.C. Water's answer to cleaner H2O, day and night as she works to reroute polluted water away from area rivers. (Marina Cracchiolo/The Washington Post)

A massive machine called Lady Bird that is digging under Washington as part of a project to build a new sewer tunnel is expected to emerge this week from underground.

DC Water officials said Lady Bird — a huge tunnel-boring machine that is longer than a football field and weighs 1,300 tons — has dug 4½ miles underground over the last two years in the Anacostia River tunnel system. Crews were expected to bring the huge machine up to the surface Wednesday afternoon, using a special crane to carry it more than 100 feet through a vertical shaft, according to authorities.

But there was a delay in getting some handles welded on to part of the machine to help bring it up, so the effort was postponed by a day. Now crews are planning to pull it out Thursday, according to DC Water officials.

When Lady Bird does emerge, authorities said it will be time for another boring machine to move in and dig as part of several different contracts on the $2.6 billion sewer project.

“She’s done,” said John Lisle, a spokesman with the DC Water department.

A look at Lady Bird. A giant mechanical drilling machine.

Engineers call Lady Bird a marvel of technology, and it does about a dozen things at once. The sewer tunnel project stretches 13 miles from the Bloomingdale neighborhood to the Blue Plains facility in Southeast Washington. It is expected to be completed in 2022.

The goal of the sewer tunnel project is to reduce the combined sewer overflows to the Anacostia and Potomac rivers by 96 percent, according to Lisle.

Like most hip ladies in the city these days, Lady Bird has her own Twitter handle — @LadyBirdTBM — where it gives updates.

On Tuesday, one of the posts read, “if I see my shadow when I come out tomorrow, that means 6 more weeks of miserably hot, humid weather.”