Army Corps of Engrs and the Navy had to develop Contingency of Operations Plans and Emergency Contingency Plans for both the port operations and Levee systems/pumping stations as part of Y2k funding requirements. The same was probably in effect for Louisiana and NO governments in receipt of federal funding. I suspect they're sitting on a shelf somewhere because of BRAC and downsizing of engineering within DOD, not to mention the "I manage COTS better than you can design it" mentality.
So I really wonder why there weren't more substantial immediate actions in place prior to the hurricane hitting, regardless of when the levees broke.
The SuperSack/Jersey turnpike barrier fill via SkyCrane is one of the nuttier ideas around when one lives on the bayou and Army Corps of Engineers should have access to some fairly heavy lift barge equipment or hovercraft even.
I've wondered why some LCACs weren't immediately dispatched from Little Creek, but at least the IwoJima is in route and might be equipped accordingly. Same situation on osmosis units for 5000 people a shot.
Of all the news coverage, I've been amazed to not have seen anything regarding dredging, barging, tow boats, or other commercial maritime activity to get bulk logistics rolling. Maybe the US simply lacks industrial capacity today.