I found (via KOS) the most awesome, in-depth article about the history of us attempting to prevent change to the Mississippi, the Atchafalaya and why the Mississippi needs to run down there, why we are trying to keep the Mississippi flowing by New Orleans, why that is so important to our commerce, etc.
It was written in 1987. And everyone at that time recognized it would just be a matter of time before the Mississippi blew out the Army Corp control methods, and chose it's own preferred course to the Gulf via the Atchafalaya.
Long, but worth it:
The Control of Nature
ATCHAFALAYA
by John McPhee February 23, 1987
The New Yorker Magazine.
http://www.newyorker.com/archive/198...#ixzz1MXcmXetG
Edit: and another good review of the rivers and flood control systems, historically and today:
http://www.americaswetlandresources....erControl.html