DC Water to begin ground stabilization phase of Potomac River Tunnel Project
Next month, DC Water will commence work to stabilize the ground prior to beginning excavation for the Potomac River Tunnel Project.
Using a large drill for deep foundation work, workers will lower a steel cage into each drilled hole and pour concrete into it. These concrete columns, known as secant piles, will serve as a retaining wall to avert soil collapse and groundwater intrusion during the excavation process. A notice will be distributed in July to announce the commencement date for this work, DC Water said in a news release.
To avoid excessive disruption during the construction phase, DC Water has also opened a new portion of the Capital Crescent Trail in Georgetown, serving as a detour around the Potomac River Tunnel Project construction site.
DC Water will also be Installing protections for its Upper Potomac Interceptor (UPI), a four-foot diameter sewer line serving the surrounding county.
About the Potomac River Tunnel
The next major phase of DC Water’s Clean Rivers Project, the Potomac River Tunnel will include a 5.5-mile tunnel system, including diversion facilities, drop shafts, and support structures. When finished, the tunnel system will contain and divert both sewage and stormwater to the Blue Plains Advanced Wastewater Treatment Plant.
Each year, DC Water stated, about 650 million gallons of untreated sewer overflows enter the Potomac River, and ultimately, Chesapeake Bay, releasing trash and increasing bacteria harmful to the environment and its wildlife.
The tunnel will reduce this volume by 93% and reduce the frequency of events from 74 to four in a year of average rainfall, ensuring compliance with a 2005 Federal Consent Decree entered by DC Water, the District of Columbia, the US Environmental Protection Agency, and the US Department of Justice, as amended in January 2016.
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