Leakage in Big Dig tunnel rises
3 years after promise, more water getting in
Almost three years after state managers vowed to close thousands of leaks in the Big Dig tunnels, nearly 2 million gallons of water flow each month through the Thomas P. O'Neill Jr. Tunnel, an 18 percent increase over last year, a Globe analysis shows.
The water is worrisome because it shows that the concerted efforts by the state to plug leaks in the $15 billion project are only marginally effective, at best, and may mean heavy maintenance costs for years to come.
"It's no secret that leaks are an issue we will have to deal with for the foreseeable future," said Jon Carlisle, spokesman for the Massachusetts Turnpike Authority, which oversees the downtown tunnel system. "It's a problem that we will need to continue to monitor and remediate."
The leaks are a continuation of a problem that has plagued the O'Neill tunnel since the roof was attached to the walls in the years before the tunnel opened in 2003. The leaks have been clustered in the seam between the wall and roof, running the length the 1.5-mile tunnel, where construction crews had trouble setting a water-proof membrane.
The problem became public after a gaping breach opened in a section of the massive tunnel walls in September 2004, sending water gushing into the northbound lanes. Edward M. Ginsburg, a retired probate judge who was then investigating the Big Dig for design mistakes on behalf of the turnpike, revealed that the tunnel was riddled with leaks.
The turnpike spends almost $5 million a year for construction crews to plug leaks in the tunnel roof and walls by injecting a grout sealant into fissures in the concrete, Carlisle said. He said the number of leaks is down to about 800 in the O'Neill, compared with more than 3,500 acknowledged by turnpike managers in 2004.
"We're chipping away at them," he said, adding that the agency expects "the leaks-chasing that's going on now to be ramped down."
Even so, Carlisle acknowledged the cost of leak-related inspections and maintenance to be a constant. He said crews aggressively attempt to plug leaks, but new leaks frequently open where patches had earlier been applied.
Also, because water weakens concrete and deteriorates steel, the state may be stuck with higher maintenance costs in the future, as more crews are needed for frequent inspections and repairs.
The Turnpike Authority last year without explanation stopped posting on its website records of water pumped out of the tunnels, and Carlisle declined to provide data to the Globe. But the Massachusetts Water Resources Authority, responding to a request made under the state Public Records Law, gave the Globe records it had received from the turnpike.
Those records show the amount of water pumped out of the O'Neill tunnel, which traverses the city some 40 feet beneath the surface, increased to 1.9 million gallons per month for the first three months of this year, compared with 1.6 million gallons per month for the same period last year.
The increase indicates that managers have been unable to deliver on their promise to plug the leaks. In November 2004, Bechtel/Parsons Brinckerhoff, the project's overall design and construction management consultant, said in a prepared statement that "the program to seal leaks will be completed within months, not years."
The severity of leaks is indicated by the amount of water that settles in the tunnel's low point tanks and has to be pumped out. The O'Neill tunnel is equipped with six heavy-duty pumps.
More snow and rain this year compared with the same period last year may account for some of that increase -- 9 inches in 2007, compared with 7.8 inches in 2006 -- because some precipitation is carried into the tunnels on motor vehicles and drips off.
However, the amount of precipitation is not a major factor in the comparison because most of it is caught in storm drains built into tunnel entrances before it gets into the tunnels, and thus is not pumped out.
Big Dig designers intended the tunnels to be virtually dry, subject to dampness on the walls and some seepage, but not to the kind of dripping that has plagued the project.
Project managers, when applying for permits to pump water from the tunnels into the MWRA system in 2002, said that only water trucked into the tunnels to be used for washing the tunnel walls would need to be pumped out. That amount -- 36,000 gallons a month -- is infinitesimal compared with the almost 2 million gallons actually being pumped out.
The MWRA revoked those permits in 2005 after the Globe reported the actual amounts of water being pumped into the MWRA sewers. The turnpike and MWRA continue to negotiate over the steps the turnpike must take to receive revised permits.
"We want them to do everything possible to minimize and reduce the amount of water coming from the tunnels into our system," said Michael Hornbrook, MWRA chief operating officer.
The source of the leak in the tunnel is ground water, which saturates the earth beneath the surface, including the area surrounding the tunnel's walls and roof. Ground water is generally free of contaminants, and thus does not belong in the MWRA's sewer system, Hornbrook said.
The MWRA's sewer system is meant to cleanse wastewater at Deer Island and dump it 10 miles offshore.
The turnpike is now pursuing environmental permits that would allow it to stop pumping its millions of gallons of ground water into the MWRA system. Instead, the turnpike would pump that water into the Fort Point Channel, so long as environmental agencies agree.
"The turnpike is in discussion with federal and state environmental permitting authorities on the best course of action for the disposal of this water," Carlisle said.
Until the MWRA began its enforcement action against the turnpike in 2005, the pumping records kept by the turnpike were rough estimates, Hornbrook said.
Since January, however, the turnpike has complied with one aspect of the MWRA's enforcement action by keeping precise, reliable daily records of the amount of water it discharges.
Using those rough numbers, the Globe reported last year that the amount of water pumped from the tunnels had been reduced by 38 percent from 2004 to last year.
But the latest numbers obtained last month indicate that that steady improvement has come to a halt in 2007.
Carlisle said the turnpike will attempt to make contractors responsible for the leaks repay the state all costs associated with repairing leaks. Attorney General Martha Coakley is leading the state's efforts to recover costs that could result in repayment of millions of dollars by contractors, including Bechtel/Parsons Brinckerhoff.
Sean P. Murphy can be reached at smurphy@globe.com. 