Anacostia River Tunnel Prevents Combined Sewer Overflows

The District of Columbia Water and Sewer Authority (DC Water) announced that the Anacostia River Tunnel kept more than 4.5 billion gal of combined sewer overflow and nearly 900 tons of trash and other solids from entering the Anacostia River in its first year of operation.

The 7-mile-long tunnel opened March 2018 and is the first segment in the utility’s Clean Rivers Project tunnel system, a system designed to trap sewage and storm water overflows and transport it to the Blue Plains Advanced Wastewater Treatment Plant before releasing it into the Anacostia River.

“This year was the ultimate test for the Clean Rivers Project tunnel system, said DC Water CEO and President David L. Gadis in a news release. “In the rainiest year on record, the tunnel, along with green infrastructure, beat all projections for cleaning the river. The improved health of this waterway is bringing a Renaissance to the waterfront from housing, retail and sports venues, to recreational and environmental opportunities.”

The newly constructed tunnel held up well during one of the wettest years on record for Washington D.C. Throughout 2018, Reagan National Airport received 66.28 in. of rainfall, exceeding the previous record of 61.33 in. set in 1889, reported local news source WTOP.

According to DC Water, the new system exceeded expectations by achieving an 89% capture rate, a marked increase from the originally projected 80% for an average rainfall year. The Anacostia River also received its first passing grade its water quality report card in June 2018, shortly after the system went online.