Northeast Boundary Tunnel Design Services

The Northeast Boundary Tunnel (NEBT), being delivered under a design-build construction method, represents the largest component of the DC Water Clean Rivers Project Long Term Control Plan to meet combined sewer overflow control objectives, provide flood relief in the Northeast Boundary drainage area, and improve water quality in the Anacostia River. The tunnel, with 7 shafts, is approximately 27,000 feet long, 23 feet in diameter, and 60 to 140 feet below grade. Collectively, the tunnel system will enable storage and gravity conveyance of sewage to the Blue Plains Advanced Wastewater Treatment Plant.

During design, EBA provided traffic engineering services and prepared submittal packages for maintenance of traffic (MOT), temporary signals, lighting, and permanent traffic elements for the design-build team. EBA prepared 30%, 60%, and final designs, along with construction-ready submittal packages for the 10 construction staging areas.

Each submittal package included detailed MOT designs and layouts, prepared per DC Department of Transportation requirements, for each construction phase; detour plans for all travel modes; bus stop relocations; and permanent signing and marking restoration plans. EBA also provided appropriate Synchro analyses and signal timing adjustments, including temporary lane configurations and traffic routing modifications, to meet or exceed required levels of service.