• Corporate HQ, NY
  • Melville, NY
  • Iselin, NJ
  • Ossining, NY
  • Mount Laurel, NJ

Blue Plains Tunnel


The District of Columbia Water and Sewer Authority (DC Water) is implementing its $2.6 billion long-term control plan for combined sewer overflows (CSOs), known as the DC Clean Rivers Project (DCCR). The DCCR is comprised of 20 miles of 23-foot-diameter tunnels at depths from 50 to 160 feet. The system will capture CSOs and convey them to the Blue Plains Advanced Wastewater Treatment Plant (BPAWWTP), the largest such facility in the world, treating more than 330 million gallons of sewage per day.

The Blue Plains Tunnel will be a 120-foot-deep, 24,300-foot-long pioneer segment of the deep tunnel system, running under and adjacent to the Potomac and Anacostia Rivers. HAKS is a member of the consultant construction management (CCM) team providing inspection services, including tunnel and near-surface construction, for the $360 million design-build project. A 26-foot-diameter, 1,323-ton tunnel boring machine (TBM) mined predominately in soft ground using an earth pressure balance (EPB) shield. This TBM reached its destination in July 2015. The CCM team is working 24/7 on tunnel ancillary structures at four different construction sites—the 132-foot-diameter dewatering shaft and 76-foot-diameter screen shafts in the BPAWWTP; 50-foot-diameter drop/overflow shaft at the Joint Base Anacostia-Bolling; 55-foot-diameter junction and drop shafts at the Poplar Point Pumping Station; and at the Main Pumping Station. Team members are working closely with the design-build team to ensure that the underground works are constructed under strict quality assurance (QA) guidelines. Routine QA inspections include slurry wall installation and deep shaft excavation; shaft waterproofing installation; cast-in-place shaft concrete lining installation; and precast steel fiber-reinforced concrete lining installation.

Effective field coordination between the design-builder/contractor and CCM team is critical to the project.