The Potomac River Tunnel (PRT) Project is a critical phase of the DC Clean Rivers Project, designed to reduce combined sewer overflows (CSOs) into the Potomac River and significantly improve water quality. The project involves constructing a 5.5-mile-long, 18-foot-diameter deep sewer tunnel located approximately 100 feet underground, along with diversion facilities, drop shafts, and supporting structures to capture and convey flows to the Blue Plains Advanced Wastewater Treatment Plant for treatment. Currently, 8 CSO outfall locations discharge approximately 654 million gallons of CSO into the Potomac River annually during average rainfall, with around 74 overflow events. Upon completion, the PRT is expected to reduce these events to just four per year and decrease overflow volume by 93%, enhancing the environmental health and aesthetics of the Potomac River.
Design work began in 2019, and mobilization started in 2024 at West Potomac Park, with project completion targeted for 2030. Dulles Engineering provides construction quality control services on the project, including field and environmental inspections, materials testing, and structural integrity evaluation of the tunnel's shafts using Crosshole Sonic Logging (CSL). With an investment of $819 million and a construction duration of 6.5 years, the PRT will play a transformative role in protecting the region's waterways and ensuring cleaner, safer water for future generations.
DC Water
CBNA-Halmar Clean Rivers JV
Washington, D.C.
March 2024 - Ongoing
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