Water began pouring into a Metro tunnel Thursday morning resulting in train delays for Yellow Line riders as the transit agency worked to plug the hole. See a video of the water gushing through a hole in the tunnel wall.

WASHINGTON — Water spewing through the wall of a Metro tunnel between the L’Enfant Plaza Station and the Potomac River forced trains to use a single track through the area for about three hours on Thursday.

Metro said one track was shut down shortly after that train operator reported the water around 11:30 a.m. Thursday. Trains resumed regular service south of L’Enfant Plaza about 2:30 p.m.

Engineers do not believe the water threatens the structural integrity of the tunnel, Metro spokesman Dan Stessel said. But the cause of the water gushing through a hole in the tunnel wall was not immediately clear.

The leak was about 2,000 feet from the L’Enfant Plaza Station, Stessel said, which would put it near or under the Washington Channel, a waterway separating the Southwest Waterfront from East Potomac Park.

Stessel said it appeared the water was coming from outside the Metro system.

DC Water said there were no reported water main breaks nearby.

Metro has long had problems with water entering the underground system and has dedicated a team to resolving water issues on the Red Line during the last several months.

Metro provided this video of water pouring into the Yellow Line tunnel: