Well they can punch some holes into the levees down after the storm passes. That will allow some islands to form in the bowl, if any of the bowl is above sea level. That might help to pick up anybody who remains alive.
They will have no other recourse. Hopefully the Engineers have taken it into account and have the demo guys on standby. The demo guys I'm talking about would be Navy Seabees and Combat Engineers.
The bowl is 6-18 feet BELOW sea level. The only places higher is where it was filled under structure. So tall building are above water, but travel will be impossible.
Only pumps will be of any value, and they do have plenty of those, but they need electricity.