Design-Build Main Pumping Station Diversions, Division I


DC Water


Washington, DC

Key Challenges & Project Details

  • Project provides control and consolidation of flow coming from Combined Sewer Overflow (CSO) Structures: New Jersey Avenue Arch Combined Sewer – 18-ft. wide and 20-ft. high in section (CSO 009/011A), Tiber Creek Arch Combined Sewer (CSO 012), Canal Street Sewer (CSO 013), and Tingey Street Sewer (CSO 014).
  • Two reinforced concrete hydraulic diversion structures constructed around CSO 009/011A and CSO 012: 60-ft. x 70-ft., 30-ft. deep for CSO 009/011A and 60-ft. x 50-ft., 25-ft. deep for CSO 012. Existing structures were demolished within the interior of the new structures.
  • Both diversion structures exit into a reinforced concrete surge tank 50-ft. x 80-ft., 40-ft. deep.
  • A cast-in-place concrete box approach channel carries the exiting flow from CSO 012 into a junction chamber and then into the Surge Tank.
  • Extension of 72-in. Tiber Creek Sewer for 172-ft. from the terminus of Division ‘B’ project on the west side of this project to the junction chamber above. Part of the sewer extension passes beneath the Tiber Creek Sewer (CSI 012) and required 96-in. hand mined tunnel construction.
  • A combined reinforced concrete below-ground and masonry above-ground odor control structure.
  • Within the 110-ft. deep tunnel drop shaft, the following items of construction were completed: the base swirl facility, the interconnecting walls and channels from the surge tank and odor control facility, as well as 2-ft. thick 56 ft. diameter cast-in-place concrete suspended roof