For the sake of perspective: A mere $1 quadrillion would dwarf the U.S. gross domestic product, which Scott said was $13.2 trillion in 2007. A stack of one quadrillion pennies would reach Saturn.

Some residents may have grossly exaggerated their claims to send a message to the corps, which has accepted blame for poorly designing the failed levees.

"I understand the anger," Scott said. "I also understand it's a negotiating tactic: Aim high and negotiate down."