The Northeast Boundary Tunnel (NEBT) is designed to increase the capacity of the sewer system, significantly mitigating the frequency, magnitude and duration of sewer flooding and improving the water quality of the Anacostia River.
The contract was awarded by the District of Columbia Water and Sewer Authority (DC Water). Salini Impregilo has a 30% stake in the joint venture and Lane the other 70%.
The NEBT is the biggest component of DC Water’s Clean Rivers Project. It will run between 15m and 49m below ground along an 8.2km route. It will be aligned to intersect existing chronic flood areas along Rhode Island Avenue NW.
In times of flooding, the tunnel will receive flows from the sewer system captured by diversion facilities and convey them to DC Water’s Blue Plains Advanced Wastewater Treatment Plant. The NEBT project will also include the construction of ventilation control facilities, storm water inlets, and green infrastructure.
Work is expected to begin in September and be completed in 2023. Healy and Salini Impregilo are also working on the Anacostia River Tunnel, another component of the Clean Rivers project.