Wrapping Up Construction of the Northeast Boundary Tunnel

The commissioning of the Northeast Boundary Tunnel (NEBT) completes the Anacostia River Tunnel system. The NEBT was placed in operation on September 15, 2023. It completes all the CSO controls required for the Anacostia River, providing a 98% reduction in CSO overflow volume in an average rainfall year. In addition to controlling CSOs, the construction of the NEBT reduces the chance of flooding in chronic flood areas from approximately 50 to 7 percent in any given year.

The federal government built much of the District’s sewer infrastructure in the late 1800s and early 1900s. The sewer system serves the dual purpose of collecting wastewater from homes and businesses and stormwater runoff from streets and properties. Referred to as combined sewers, these systems continued to serve the District as development transformed low-density rural areas into densely populated neighborhoods. The 19th-century system was undersized when originally constructed and that condition has been exacerbated by population growth and development. This has contributed to the chronic flooding in the Bloomingdale and LeDroit Park neighborhoods, the Rhode Island Avenue Metro Station area, and Mount Olivet Road NE for decades.

To mitigate the problem, DC Water constructed the NEBT to connect with the existing sewer system, significantly mitigating sewer flooding while improving the water quality of the Anacostia River. Combined sewage captured by the NEBT would eventually be transmitted to the Blue Plains Advanced Wastewater Treatment Plant. The NEBT is the largest component of the Clean Rivers Project and starts just south of the RFK Stadium and extends north to Rhode Island Avenue NE and west to R Street NW.

Scope of Work

• Installation of 27,000 foot long, 23 foot diameter reinforced concrete tunnel
• Tunnel approximately 50 to 160 feet deep
• Construction of diversion facilities sited near chronic flood areas to relieve the existing sewer system and divert combined sewer flows to the NEBT
• Ventilation control facilities to regulate air flow in the tunnel system

Partners

DC Water worked closely with multiple stakeholders, including residents, Advisory Neighborhood Commissions, District Department of Transportation, District Department of Public Works, District Department of Energy and Environment, Office of the Deputy Mayor for Planning and Economic Development, CSX, Amtrak, District Department of General Services, DC Sports and Entertainment Commission, National Park Service, and the Washinton Metropolitan Area Transit Authority. 

Project Location Map