It would leave Baton Rouge and Nawlins dry and run through Morgan City instead...The main problem (I haven't read the article yet) is that the Mississippi no longer replenishes the delta with fresh soil. The real bugaboo is where the river really wants to go - the Atchafalaya Basin. Then, you've have the same effect on the west side of the state. Also, the map should include SE MS, in order to get the true picture...
When Katrina hit the levees on Lake Ponch broke. If it had been the river levees it would have killed 10s of thousands. Like a big bath tub and the faucet broken....it would have kept filling up with nothing to stop it