CONCERN IS mounting over the apparent multiplication of leaks in Boston's $14.6bn 'Big Dig' highway tunnel.
Alarm over widespread leakage in the walls of the 6.4km long Central Artery tunnels, constructed to beat congestion around Boston harbour, was first flagged up in 1999 by project managers Bechtel and Parsons Brinckerhoff. They were patched.
But last September water started pouring through a tunnel wall, forcing lane closures.
There are now an estimated 500 leaks in the walls and ceiling, with more opening up as fast as repairs can be carried out.
Client the Boston Turnpike Authority claims the tunnels are safe and that outstanding work to install drainage above the tunnel alignment will reduce the problem.