Idiot terrorist plot: New York tunnels

Yesterday, the New York Daily News broke a story about an al-Qaeda plot to detonate explosives in the Holland tunnel, the goal of which was to flood lower Manhattan with water, much like New Orleans was flooded after Hurricane Katrina.

An interesting idea, except for one major engineering problem: Manhattan is above the level of the Hudson River. The reason New Orleans was flooded when the levees were breached was because it is below the level of the Mississippi River and Lake Pontchartrain. New York, on the other hand, does not need levees to protect it from the Hudson River - Manhattan is a natural island above the water level. Even if they succeeded in rupturing the tunnel wall, it would only cause flooding in the subway system - and nothing that could not be quickly fixed.

Another major engineering problem is the strength of the tunnels, and the amount of explosives this would require. The terrorists allegedly planned to bring explosives in backpacks onto a PATH train connecting New Jersey to New York City. When you realize that these explosives would need to not only rupture the train car, but would need to get through the concrete and steel-reinforced tunnel tube, and 40 feet of bedrock above, with the pressure of the river water pushing down on the bedrock and tunnel walls (and acting against the force of the explosive), you realize the amount of explosive needed to accomplish this task is monumental. And these guys were planning to carry this explosive onto the train in backpacks?

What a bunch of idiots....