the only major levees in the country are built and maintained by NOLA area agencies.
This is news to me. The news media has stated it is the responsibility of the Army Corps of Engineers.
I'm as confused as you are.
But it may be that local committees (party hacks, featherbedders) get paid salaries to oversee the "maintenance" of the levees, while constructing them or major strengthening projects are done by Army Corps of Engineers contractors.
Money may go to both ends -- maintenance and construction.
Where the money comes from and where it goes is a good question.