The Third Street Tunnel was closed Monday in both directions after water poured down onto the roadway and caused damage. The closure created traffic gridlock around the heart of Washington and left nearby residents without water.

       Support our journalism. Subscribe today. arrow-right

       The stretch of road, at the northern terminus of Interstate 395, was closed near New York Avenue after pooling water was found in the southbound lanes of the highway. Police also closed nearby roads before 7 a.m. as traffic backed up for miles during the morning rush.

       The tunnel, which runs beneath the National Mall, is a major commuter thoroughfare into downtown Washington. Officials did not have an estimate for when the tunnel would reopen but said closures would probably be in place through Monday.

       Story continues below advertisement

       Kishia L. Powell, D.C. Water’s chief operating officer, said crews turned off three water mains in the area about 9 a.m. Monday to look for the water leak’s origin.

       Advertisement

       “We’ve isolated them to determine the exact source of the intrusion,” she said.

       Chris Geldart, the city’s deputy mayor for public safety and justice, said structural engineers looked for damage to the tunnel that might have been caused by the leak but had “no major concerns.”

       Six buildings along K Street between Second and Fourth streets NW in the Mount Vernon Triangle neighborhood had no water or low water pressure, D.C. Water officials said. They did not know how many customers were affected.

       Story continues below advertisement

       Drivers were advised to avoid the area. D.C. police said other closures include:

       · The Third Street Tunnel’s southbound entrance at Fourth Street and New York Avenue NW.

       · The southbound side of Fourth Street near M Street NW.

       · The eastbound side of New York Avenue NW at Fifth Street.

       · The southbound side of Third Street near New Jersey Avenue NW.

       Advertisement

       · The southbound side at New Jersey Avenue and N Street NW.

       · The northbound side at New Jersey Avenue and K Street NW.

       The ramp at Massachusetts Avenue into the tunnel also was closed, as was the 200 block of K Street NW.

       The water mains that were shut off include two that are about eight inches in diameter and another that is about 30 inches. The mains run above the tunnel along K Street, D.C. Water officials said.

       D.C. police initially indicated a sinkhole had formed in the tunnel, but officials later determined the road was damaged after water gushed down from above.

       “It must have gotten under the asphalt and made it buckle,” said John Lisle, a spokesman for D.C. Water.

       Other agencies also responded to the leak, including D.C. police and the District Department of Transportation.