DC Water Anacostia River Tunnel


Washington, D.C.


Civil Engineering

Project Size

2.4 Miles

Completion Date


Total Cost



Parsons Professional Corporation

Wiles Mensch Corporation – DC (WM) provided civil engineering services as part of the of the design team in conjunction with design-build services for the Anacostia River Tunnel (ART). The project is part of the DC Clean Rivers Project (DCCR) effort to control combined sewer overflows (CSO) into the Anacostia River. WM services included DOEE permitting, erosion and sediment control plans, stormwater management approval, Storm Water Pollution Prevention Plans, NOI approval, as well as grading, paving and BMP design services.

The construction for the ART contract included a large diameter tunnel excavated in soft ground, six shafts, three adit connections, two diversion structures, internal hydraulic structures, odor control and venting facilities, and hydraulic monitoring and data collection system. The tunnel is 23-feet in diameter (inside), 12,500 feet (±) long, and 100 feet (±) deep. The six shafts range in diameter from 15 to 75 feet (±) in diameter (inside) with invert depths of 100 feet (±) below the ground surface. The three adits range from 20 to 300 feet (±) in length and 4.5 to 10 feet in diameter (inside). The invert depths for the diversion structures are 20 to 35 feet (±) below the ground surface. The construction also included the start-up of the tunnel system south of RFK Stadium and coordination with the tunnel system dewatering pumping station.

The Anacostia River Tunnel connects to the Blue Plains Tunnel at Poplar Point and delivers captured combined sewer overflows to the Blue Plains Advanced Wastewater Treatment plant for treatment prior to discharge to the Potomac River.

Photos courtesy of: DC Water

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