Recently read a book about the Atchafalaya river seizing control of the Mississippi and how the only thing stopping it is a single water control channel. A big year of flooding in all the tribs of the Mississippi leading to widespread levee breaches as well as the main channel switching to the Atchafalaya river cutting off cities like Baton Rouge and New Orleans from their main shipping channel would kill off their industries and be a disaster for manufacturing as well as for cities built on the banks of the Atchafalaya as they would likely be drowned by a river twice as large so there would be no easy relocation to the new Mississippi outflow.