A major sewer line along Clara Barton Parkway near the I-495 interchange and the Chesapeake and Ohio Canal National Historical Park collapsed on January 19, releasing an estimated tens of millions of gallons of wastewater per day into the Potomac River.
Following a recent inspection, officials with DC Water discovered a previously unknown obstruction inside the damaged pipe, consisting of a rock barrier stretching about 30 feet downstream from the collapse. The finding revealed that the blockage was more severe than initially believed and will extend the timeline for repairs. Crews now expect it will take an additional four to six weeks to install larger bypass pumps, stabilize the site, and prepare for safe removal of rocks and debris. The agency plans to add five more high-capacity pumps, increasing the total to 13, to divert wastewater and limit flow through the damaged section.
Officials said the rocks blocking the interceptor likely originated from construction backfill dating to the 1960s and were pulled into the pipe when the collapse occurred, forming a dam as additional soil and debris eroded into the system. Because standard cleaning equipment cannot remove large boulders, crews will rely on a combination of manual labor and heavy machinery. During the repair period, some risk of limited overflows remains, and DC Water continues to work with federal, state, and local agencies on environmental monitoring and remediation. Since late January, daily water quality testing has been conducted at multiple locations, with results showing mostly declining but fluctuating levels of E. coli bacteria. Officials said variations are influenced by weather, snowmelt, and natural sources, and that monitoring will continue as repairs progress.
