Construction of the largest and final segment of the Anacostia River Tunnel System is set to begin this month. Part of DC Water’s larger $2.7-billion Clean Rivers Project to help the District of Columbia comply with the Clean Water Act, the project includes a 13.1-mile-long tunnel system—to be completed in 2023—that will capture 98% of sewage overflows to the Anacostia River.
The final $580-million, five-mile section known as the Northeast Boundary Tunnel is the most expensive of the four Anacostia tunnel segments. A joint venture of Salini Impregilo and S.A. Healy was selected for the design-build project, which includes a 23-ft-dia reinforced-concrete tunnel to be burrowed up to 160 ft below ground. The effort will help relieve chronic sewer flooding in several areas of northeast D.C. by diverting combined sewer overflow to the tunnel.