Salini Impregilo and The Lane Construction Corporation have won a $580M contract to build the Northeast Boundary Tunnel (NEBT) project in Washington, D.C. The NEBT will be a large, deep sewer tunnel that will increase the capacity of the District’s sewer system, significantly mitigating the frequency, magnitude and duration of sewer flooding and improving the water quality of the Anacostia River.
As joint-venture partners, Salini Impregilo and Lane’s S.A. Healy won the contract from the District of Columbia Water and Sewer Authority (DC Water). Salini Impregilo has a 30 percent stake in the joint- venture and Lane the other 70 percent.
The NEBT is the biggest component of DC Water’s Clean Rivers Project. It will be 15m – 48m below ground and run 8.2km from just south of Robert F. Kennedy Stadium to the intersection of Rhode Island Avenue NW and 6th Street NW. It will be aligned to intersect the 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.
Once it is connected to the other Clean Rivers Project tunnels, the NEBT will help reduce combined sewer overflows to the Anacostia River by 98 percent and the chance of flooding in the areas it serves from about 50 percent to seven percent in any given year.
Work is expected to begin in September 2017 and be completed in 2023 – two years ahead of the Consent Decree schedule. Lane’s S.A. Healy and Salini Impregilo are also working on the Anacostia River Tunnel, another component of the Clean Rivers Project.