RiverRenew Tunnel System Project
Alexandria, Va.
Merit Award
Sent by: AlexRenew
Owner: AlexRenew
Leading design company and civil, structural, electrical and mechanical engineer: Jacobs Engineering Group
General contractor: Taylor-Shay JV
Owner Advisors: Brown and Caldwell and Schnabel Engineering
Resident Engineer: EPC consultants
Subcontractors: Kokosing Industrial Inc.; Keller North America; Bulldog Distribution Trucking; Bay State Prefabricated; Herrenknecht; Huxted Tunnel
Completed on budget and on schedule, despite an aggressive schedule and pandemic-related cost increases, the complex project eliminates long-standing combined sewer overflow problems that previously dumped approximately 140 million gallons of untreated sewage into local waterways annually. Replacing sewers dating back to the 1800s, the new system reduces overflow volume to less than 16 million gallons per year and decreases the average annual frequency of overflows to less than four events out of 70.
The team employed a variety of construction methods to build the system, including an earth pressure balance tunnel boring machine that bored a 2.2-mile-long, 130-foot-deep oceanfront transportation and storage tunnel. Two 35-foot drop shafts and diversion facilities were also constructed along the tunnel route. A large 12-story deep wet weather and dewatering pumping station located at the heart of the city’s wastewater treatment facility houses the pumps and equipment required for a 20 million gallon per day, 180 mgd wet weather treatment capacity tunnel dewatering pumping station.
