re: Mississippi River diverging: When do we finally let it go down the Atchafalaya?

A couple things I don't understand. If the river would naturally replace the sediment if it followed the course that the river wants to take, shouldn't it be creating new wetlands elsewhere? That silt has to go somewhere.

Someone said if the current course had 30% of the flow, salt water would contaminate the local drinking supply (as if that nasty water is actually clean right now. I've inspected way too much of the infrastructure in Nola to pretend it's drinkable). So what percentage of average flow would be maintained to keep the salt water from intruding? Is there a way to do both, but just at lower levels, or would that just be a bandaid on the problem?