List of tunnel troubles grows longer

The Big Dig's tunnel leak problem is far more costly and extensive than Massachusetts Turnpike officials and private contractors have acknowledged, involving thousands of ceiling and wall fissures, water damage to steel supports and fireproofing systems, and overloaded drainage equipment, according to documents obtained by the Globe.

Turnpike officials and private-sector managers Bechtel/Parsons Brinckerhoff have together signed off on at least $10 million in cost overruns to repair the leaks and water damage since early 2001, the records show, and the problem persists.

Turnpike officials did not acknowledge the leak problem until it was revealed in the Globe last week.

All this occurred while engineers worked frantically to come up with a permanent solution for waterproofing the tunnels, an effort that continues today, according to project documents.

The problem stems in part from an apparent projectwide failure in the original design of the waterproofing system, a critical feature of a tunnel that sits almost entirely beneath the salty water table of downtown Boston. In a confidential report commissioned by the Turnpike in 2001 by the auditing firm Deloitte & Touche, project officials acknowledged that ''the original design provided insufficient protection against leaking" at the top of tunnel walls.

With construction of the tunnels well underway and with water seeping in through joints between the roof and tunnel walls and between panels, Bechtel/Parsons Brinckerhoff abandoned its initial waterproofing system, a membrane applied to the roof and walls that had proved incapable of stopping water. Contractors were ordered to apply a spray-on application instead.

Doug Hanchett -- spokesman for the Massachusetts Turnpike Authority, which oversees the Big Dig -- said that the agency has made progress in controlling the leak problem and that the authority is working to recoup costs from contractors.

''This issue is something that will resolve itself through the construction process, and we fully expect that the contractors will perform the waterproofing work, as required in their contracts," Hanchett said.

Earlier this month, a team of independent engineers hired to investigate a massive leak that erupted in September said the project was riddled with more than 400 leaks throughout the tunnel system.

However, the documents obtained by the Globe show nearly 700 leaks in just one 1,000-foot section of the Interstate 93 tunnels beneath South Station. The documents include memorandums, diagrams, photographs, and correspondence pertaining to the Central Artery tunnels.

According to documents detailing modification to tunnel finishing contracts, which were obtained by the Globe, the Turnpike Authority and Bechtel/Parsons Brinckerhoff established a Leak Task Force in early 2001 and are now allocating $250,000 a month for the firm McCourt/Obiyashi to send repair teams into virtually all sections of the I-93 tunnels. McCourt/Obiyashi's initial contract, which began in 1999, had no such provisions for leak repair, but by mid-2001 the firm was extensively engaged in that effort, the documents show.

For example, in August 2003, tunnel officials, approved a $205,000 plan to replace 300 wall panel connectors in the downtown tunnels because ''excessive tunnel leakage with high salt content has caused unacceptable corrosion."

In another instance in March 2001, McCourt/Obiyashi was told to extend tubes that contained liquid concrete grout for leak repairs throughout the tunnels. That work cost $300,000.

George J. Tamaro, an independent engineer hired by the Turnpike Authority to investigate the source of the massive tunnel leak that erupted in September, said that the roof's waterproofing membrane didn't work as intended and that engineers have used concrete grout for several years to try to plug the leaks. He said problems with leaks seemed to occur when the weather becomes colder.

Tamaro and another engineer hired to investigate the situation, Jack K. Lemley, said a permanent solution is needed, or workers will spend years, perhaps even a decade, patching and repatching the leaks.

Anthony Lancellotti, a Bechtel/Parsons Brinckerhoff design executive, said that ''there are a lot of theories" on the cause of the leaks and that he is not allowed to discuss them because of ongoing investigations by Bechtel/Parsons Brinckerhoff, the Turnpike Authority, the state attorney general's office, and the US Department of Transportation's inspector general.

But Lancellotti insisted that there has been a dramatic drop in the number of leaks due to ongoing repairs. He said that using grout to close leaks is a hit-or-miss proposition. Workers drilling into the concrete to inject the grout are never sure the holes they have drilled intersect with the path of the leak.

''Drilling is exploratory," he said. ''You chase leaks; that's the nature of the business. But we have seen a dramatic improvement."

Attorney General Thomas F. Reilly, who said his office is meeting regularly with engineers trying to get refunds for shoddy work, predicted that the cost of fixing the roof leaks will be much more than the $10 million already spent by the Turnpike Authority, and he called on the contractors involved, including Bechtel/Parsons Brinckerhoff, to cover those costs.

In addition to the $10 million allocated so far, project contractors who built the tunnels have on their own spent at least $6 million plugging leaks, according to construction industry officials who spoke on condition of anonymity.

Some of the contractors are now pressing hard to be compensated by the state for those expenses.

One firm, Modern Continental, has submitted a bill of roughly $4 million for leak repair work, and is asserting that the leakage problem is the result of a flawed design by Bechtel/Parsons Brinckerhoff.

But the Turnpike Authority and Bechtel/Parsons Brinckerhoff have insisted that the design was appropriate.

Raphael Lewis can be reached at rlewis@globe.com. Sean Murphy can be reached at smurphy@globe.com.