Cars pass a flooded area of the northbound lanes of the Central Artery tunnel this afternoon. (Globe Staff Photo / Evan Richman)
Water leak inside Central Artery tunnel causing major traffic problems
BOSTON -- A leak in the $14.6 billion Big Dig resulted in a big headache.
Gridlock ensued when water began leaking into the northbound lanes of the tunnel, at one of its deepest points, just north of South Station at about 1:45 p.m. Wednesday. The tunnel carries Interstate 93 through the city.
The water resulted in two lanes of the tunnel being closed to traffic underneath downtown Boston, shortly before the evening rush hour was to begin. The closure was soon reduced to one lane.
Northbound traffic headed into the city was backed up for miles behind the leak on the Southeast Expressway, and entrance ramps to the tunnel from the Massachusetts Turnpike and from Boston city streets were closed.
Keith Sibley, construction director for Bechtel/Parsons Brinckerhoff, the consortium overseeing the massive project, said the likely cause of leak had been identified, and that repairs would begin Wednesday night.
The explanation didn't soothe Turnpike Authority Chairman Matthew Amorello, who deemed the problem and the resulting delays "unacceptable."
"As a customer of the product we constructed, I'm not happy right now," said Amorello, whose agency, the Turnpike Authority, oversees the project. "We'll get to the bottom of this, we'll correct the problem."
Sibley explained that an eight-inch pocket of clay mixture in the tunnel walls was likely to blame for the leak. Water found its way into the pocket, and the high pressure at the tunnel's extreme depth -- 110 feet below the earth -- likely resulted in the leak, he said.
Sibley said the leak, which occured in a portion of the wall which has been in place for 10 years, posed absolutely no structural threat to the tunnel itself.
By Wednesday afternoon, the leak had largely subsided and the lane closure was down to one lane from two. But the back-up, at its height, extended south to Quincy, about 10 miles away.
The project replaced the elevated Central Artery of Interstate 93 with underground tunnels through downtown Boston. It also connected Interstate 90 -- the Massachusetts Turnpike -- to Logan International Airport, and added the Ted Williams Tunnel beneath Boston Harbor.