A note from the past:
"110 mph winds and power failures were reported in New Orleans. The eye of the storm passed to the southwest of New Orleans on a northwesterly track. The northern and western eyewalls covered Southeast Louisiana and the New Orleans area from about 8 pm until 4 am the next morning. In Thibodaux winds of 130 mph to 140 mph were reported. [...]
[The storm] also drove a storm surge into Lake Pontchartrain, just north of New Orleans, and the Mississippi River Gulf Outlet [...]. Levees for the Mississippi River Gulf Outlet along Florida Avenue in the Lower Ninth Ward and on both sides of the Industrial Canal failed. The flood water reached the eaves of houses in some places and over some one story roofs in the Lower Ninth Ward. Some residents drowned in their attics trying to escape the rising waters.
These levee breaches flooded parts of Gentilly, the Upper Ninth Ward, and the Lower Ninth Ward of New Orleans as well as Arabi and Chalmette in neighboring St. Bernard Parish. [...]
Those who did not have family or friends with dry homes had to sleep in the shelters at night and forage for supplies during the day, while waiting for the federal government to provide emergency relief in the form of trailers. In all, 164,000 homes were flooded. [...]
Evidence suggests that cheap construction and poor maintenance of the structures led to the failure of the levees. However, popular rumor persists that they were intentionally breached, possibly as a means of salvaging the more prosperous French Quarter."
Three years ago this week? Nope. September 1965, from the Wikipedia article on Hurricane Betsy. Katrina was no fluke. If (when) Gustav or some other storm creates a similar scenario, that will be no fluke either. These things are predictable; inevitable even.