But what if the worst happens and even the new mega-levee system fails? And how can the city be protected during the ten years it would take to build the new levees?

"We're not out of the woods," said Suhayda. "There is not a single fix to this."

Instead, a series of projects need to be initiated inside the city to protect it immediately from a repeat of the Katrina's chaos.

Suhayda and his colleagues propose a three-tiered approach that gives the city and its residents three levels of protection against a "Level 6" hurricane, as he likes to call it.

The first tier goes along with raising the levees: an upgraded pumping system that can move a lot more than the current half-inch-per-hour from inside the city. The next tier of protection is to compartmentalize the city so that a few levee breaches can't flood the entire thing.

"You don't let a hole in one part of the hull sink the whole ship," said Suhayda. "You close the water-proof doors and go on."

The last layer of protection: build watertight walls around vital buildings and move power generators and other vital technology onto the levees or other high ground. These are perhaps the cheapest and most immediate steps that can be taken, said Suhayda.

NEXT: The Southern Surge