BOSTON (AP) — Water continues to leak steadily into a Big Dig tunnel, an independent analysis shows, despite assertions by officials of the agency overseeing the project that the problem is under control.
The analysis by an independent engineering firm contradicts a report last month by the Massachusetts Turnpike Authority that water discharge from the Thomas P. “Tip” O’Neill Jr. tunnel — a section of Interstate 93 beneath downtown Boston — was cut in half from 2003 to 2006.
Big Dig project manager Michael Lewis told the MTA board that reduction indicated the leaking was at least under control. But new state Transportation Secretary Bernard Cohen asked consultant engineers to look at the data, which they described as “at best … ambiguous.”
The engineering firm of Wiss, Janney, Elstner Associates Inc. reported that Mr. Lewis’ data “does not in our opinion support the claim that water seepage rates have been declining over the past three years.”
Cohen spokesman Erik Abell said there was no imminent safety concern but that the leaks can lead to long-term corrosion.
Eight million gallons of water were discharged from the O’Neill tunnel pump stations in the first half of 2005, compared with 7.5 million gallons in the first half of this year, the engineers said in their report. A total of 6.5 million gallons were discharged in the first half of 2006.
The Turnpike Authority board meets today, and member Mary Connaughton said she wanted to know why there was such a disparity in the numbers.
“This is an issue that certainly needs resolution,” she said. “It’s very important for the Turnpike Authority board to get the most accurate information as possible.”
Spokesmen for Cohen and the Turnpike Authority said Bechtel/Parsons Brinckerhoff, the private company that oversees the Big Dig, provided much of the information for Mr. Lewis’ report last month. Neither Mr. Lewis nor Andy Paven, a spokesman for Bechtel/Parsons Brinckerhoff, returned calls left yesterday by the Associated Press.
Bechtel/Parsons Brinckerhoff is negotiating with state Attorney General Martha Coakley as part of her cost-recovery investigation into faulty work in the project, including the leaks in the tunnel.
Leaks have beset the $14.8 billion project — the most expensive public works construction in U.S. history — since it buried Boston’s Central Artery in a tunnel system. A large leak into the O’Neill tunnel in September 2004 backed up traffic for miles.
Leaking is common in large tunnels, officials say, and most of the time motorists wouldn’t know about it. The leaks drain into holding areas below the surface, and pumps discharge the water.
After the large leak in September 2004, inspectors looked at each of the approximately 2,000 underground wall sections in the I-93 tunnels, discovering 169 defects. The majority of those panels required minor patching, while another 42 needed more extensive repairs.
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