Big Dig tunnels riddled with leaks, officials deny design flaw

Boston’s Big Dig project has developed between 400 and 700 leaks, which have cost $10 million in overruns to repair.

According to documents obtained by The Boston Globe, water damage has caused thousands of ceiling and wall cracks and damage to steel supports and fireproofing systems, and has overloaded drainage equipment. Reports state the leaks are the result of a project-wide failure in the design of the original waterproofing system. Deloitte & Touche, a private auditing firm, acknowledged in a 2001 report that “the original design provided insufficient protection against leaking” toward the top of the tunnel walls, according to the Globe. Contractors Bechtel/Parsons Brinckerhoff originally waterproofed the tunnel by applying a membrane to the roof and walls. When it proved not to be waterproof, contractors applied a spray-on water-resistant application.

Doug Hanchett, spokesman for the Massachusetts Turnpike Authority, said contractors are expected to perform the waterproofing work at no cost because it is required in their contracts. In 2001, the Turnpike Authority, together with Bechtel/Parsons Brinckerhoff, established a Leak Task Force. The Task Force currently allocates more than $250,000 each month to contracting firm McCourt/Obiyashi to repair leaks in all sections of the Interstate 93 tunnels.

In addition to the $10 million spent on fixing leaks since 2001, project contractors have spent as much as $6 million on their own plugging leaks. One of the contractors, Modern Continental, has sent the Turnpike Authority a bill for $4 million in repair work. Modern states that it should be paid for its work because the leakage problem is the result of a design flaw by Bechtel/Parsons Brinckerhoff. Both the authority and Bechtel/Parsons Brinckerhoff continue to support the original design, and deny that it was flawed.

On Nov. 12, Hanchett released a statement saying the public has nothing to fear, and the tunnels are safe for travel.