DC Water’s Anacostia River Tunnel, the second design-build project in its Clean Rivers Program, has been awarded to the Impregilo/Healy/Parsons JV for $253,859,999.00. Impregilo/Healy/Parsons JV was one of three teams short-listed for this design-build contract. The award was based on a combination of technical (35%) and price (65%) proposals. The tunnel will be approximately 12,500ft long (3,840m), 23ft (7m) in diameter, and supported by a bolted, gasketed, one-pass lining system. The work will include six 90ft to 100ft (30m) deep shafts ranging from 12ft (3.6m) to 75ft (23m) in diameter. Three Adit connections are also required between the tunnel and three of the shafts; these adits will be between 4ft (1.2m) and 10ft (3m) in diameter.
The tunnel will be constructed predominately in clay. Similar to the Blue Plains Tunnel, it will require a pressurized face TBM. The contract will also include the construction of three diversions whilst maintaining flows, odor control, and venting facilities between RFK Stadium and the Blue Plains Advanced Wastewater treatment Plant.
At its southerly extent the Anacostia River Tunnel connects to the Blue Plains Tunnel at Poplar Point, east of the Anacostia River. The tunnel crosses beneath the Anacostia River just north of the new 11st Street Bridge and terminates just south of RFK Stadium within Nation Park property.
The District of Columbia Water and Sewer Authority’s (DC Water) $2.6 billion Clean Rivers is part of the agency’s Long Term Control Plan (LTCP), which aims to eliminate Combined Sewer Overflows (CSOs) into the Anacostia and Potomac rivers. Implementation of the LTCP is on schedule to achieve the first of its Consent Decree–driven milestones, which requires the Blue Plains Tunnel, Anacostia River Tunnel, and several associated near-surface facilities to begin operation by March 23, 2018.