DC Water to Hold Ceremonial Blessing for Potomac River Tunnel TBM

Monday, November 3, DC Water will host a ceremonial blessing for Mary, the massive tunnel boring machine (TBM) that will soon begin her underground journey to build part of the Potomac River Tunnel. DC Water CEO and General Manager David L. Gadis will be joined by DC Mayor Muriel Bowser, DC Water Board Chair Dr. Unique N. Morris-Hughes, and other District leaders, to mark this major milestone on the project which will dramatically improve water quality in the District.

Mary will tunnel northward from West Potomac Park, while her sister TBM, Emily, will soon arrive from Germany to dig southward. Together, they will help keep nearly a billion gallons of combined sewage and stormwater overflows from entering the Potomac River in an average year of rain.

WHAT:	Blessing Ceremony for Tunnel Boring Machine Mary — Signaling the Start of Digging for the Potomac River Tunnel
WHO:	Muriel Bowser, Mayor District of Columbia David L. Gadis, DC Water Chief Executive Officer & General Manager Dr. Unique N. Morris-Hughes, DC Water Board Chair  Moussa Wone, Vice President DC Clean Rivers Project
WHEN:	Monday, November 3, 2025, at 11:00 a.m.
WHERE:	Potomac River Tunnel Project Site West Potomac Park 4592 Ohio Dr SW (Ohio Dr & West Potomac Park Dr) Washington, DC 20551

The event entrance is located at Ohio Dr and West Potomac Park Dr. Street parking is available. Please wear closed-toe footwear appropriate for a construction site.

Following the event, attendees will have the opportunity to tour the launch site and view the drop shaft — a 100-foot-deep vertical tunnel where Mary will begin her excavation. This shaft is a key part of the tunnel system that will carry stormwater and sewage to DC Water’s Blue Plains Advanced Wastewater Treatment Plant.

RELATED: DC Water Awards $819 Million Potomac River Tunnel Contract