Pins zu company:"District of Columbia Water and Sewer Authority"

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.