Margin of safety

If the pumps fail in a noreaster, how long before the tunnel is flooded and impassable? How long do I have to get out of the tunnel before I'm swimming? What if the leak volume rises by an order of magnitude?

What I'd really like to see is a graph of pump output volume and precipitation over the past three years. C'mon, it's pretty obvious that the single slurry-wall construction technique used on this tunnel has failed. Twenty years ago, a municipal water pipe might have contributed significantly to this problem, but that's mostly fixed by now, right?

This is ground water, and it's unlikely ever to be fixed within design specs, which means a shortened safe structural lifetime. Bechtel/Parsons Brinckerhoff's offer of $300 million to get out of jail is a pittance.

(Image from a March 2005 report from the Federal Highway Administration that expected leaks to be fixed by the end of the summer of 2005.)