I think in the US we could afford to just use malathion.
Draining Florida would best be accomplished by just declaring it an exclusion zone from human habitation :) (Florida basically terrifies me more than any other state in the US, even California)
When you perform an economic analysis, you discover it would be cheaper to pay everyone in New Orleans to move away, than to let them live there and pay for the disasters that inevitably blow in from the sea. Florida is only slightly safer on average, and that only because the northern reaches are sufficiently above sea level.
New Orleans (and Florida) both are necessary port logistics areas, but shouldn't be heavily populated. New Orleans is gateway to the Mississippi which is basically the industrial/agricultural 60% center of the country.