DC Water Launches the Boring Machine Mary Under the Potomac
West Potomac Park, Ohio Drive SW, Washington, D.C. 20024, United States
District of Columbia Water and Sewer Authority
CONFIRMED90% CONFIDENCEDC Water's[1] own release of April 10, 2026 announces the launch as having happened that day.
DC Water lowered the tunnel boring machine Mary into a 100-foot-deep shaft in West Potomac Park and started her north towards Georgetown University, the first 2.4 miles of a 5.5-mile combined sewer overflow tunnel. The $819 million tunnel is part of the Clean Rivers Project and will cut Potomac overflow events from 74 a year to four; a second Herrenknecht machine, Emily, bores south towards Joint Base Anacostia-Bolling.
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