Enormous DC Water Tunnel-Boring Machine Completes 2-Year, 4.5-Mile Mission

It sounds like something from a science fiction movie: giant machines digging enormous holes 100 feet underground. But it's been happening right here in D.C.

DC Water has been using machines to build a massive underground structure that will provide a solution to combined sewer overflows in the Anacostia River and flooding in some D.C. neighborhoods.

The first phase of the 15-year Clean Rivers Project began two years ago, when the Lady Bird tunnel boring machine (TBM) began its 4.5-mile journey beneath the river. Now, the machine is being disassembled and lifted 100 feet through a shaft.

News4's Mark Segraves was there to see the bore head brought to the surface by a special crane Thursday.

The TBMs used to dig the Metro-sized tunnels are huge in their own right. The first to arrive to DC Water had a diameter of more than 26 feet and was longer than a football field.

The tunnels built by TBMs will collect combined sewer overflow and lead it to a wastewater treatment facility. Once there, the water will be treated and released into rivers as clean water.

DC Water said the Clean Rivers Project will reduce combined sewage overflow to the Anacostia River by 98 percent. The project will reduce overflow to the all bodies of water involved — the Potomac, Anacostia and Rock Creek — by 96 percent.

TBMs are named much like nautical vessels. Lady Bird was aptly named after former first lady Claudia Alta "Lady Bird" Johnson, wife of President Lyndon B. Johnson. She was known for her efforts to preserve the environment and is often credited for urging her husband to take on environmental issues.

Lady Bird and other TBMs can move up to 125 feet per day underground. They average about 70 to 80 feet daily. Lady Bird, who has been active on Twitter since her journey began, said the bore head removed Thursday is only one small part — but it weighed 215,000 pounds.

Contact Us