DC Water takes big step forward in Potomac River Tunnel project
D.C. Water is making progress with an initiative that aims to clean up the District’s waterways — the Potomac River tunnel project.
On Tuesday, a multiton cutter head was lowered to the bottom of a 100-foot shaft at West Potomac Park to attach to a tunnel-boring machine.
It’s one of two machines that will mine through soil to construct the 5.5-mile long tunnel from the Georgetown waterfront to the Blue Plains water treatment facility in Southwest.
“We are basically lifting and lowering down in the shaft the very front section of the machine that is actually able to mine through rock,” said Potomac River Tunnel Project Manager Martino Scialpi, who explained the cutter head is designed specifically to cut through rock, which makes up most of the terrain in Georgetown.
The first machine is named “Mary” in honor of Mary Edmonson, an abolitionist from Maryland who alongside her sister, Emily, attempted to escape slavery aboard the vessel Pearl in 1848.
The West Potomac Park shaft is just one of several construction sites to serve the Potomac River Tunnel during its construction.
Mary will mine north to the Georgetown waterfront, the other machine, named after Emily, will mine south to D.C. Water’s treatment facility in Blue Plains.
The project is expected to be reach its substantial completion phase in 2028, when it can likely be put into use but may require some finishing touches by crews. Construction is set to be fully complete in February 2030, the date set by a consent decree between the federal government, D.C. government and D.C. Water.
D.C. Water’s Clean Rivers Project is a $3.1 billion program to establish a series of tunnels to collect billions of gallons of combined sewer and storm drain runoff during periods of heavy rain.
The project, which has already produced three similar tunnels, is credited with significantly cleaning the Anacostia River. The Potomac River Tunnel is aimed at keeping sewer runoff from reaching the Potomac.