This bullshit of we flood your land and then we'll pay you whatever the hell we feel like is not Constitutional.
I don’t know that the C.O.E. will have to pay any damages. It seems like the farmers (or more likely their great-grandfathers) signed an easement that excludes damages for flowing water in the case of the levy being blown. The floodway (rightly or wrongly) was designed with this very situation in mind—take the pressure off of the levees by diverting a part of the flow of the river.
What I’d like to know is if the levees are blown, what happens if the Mississippi decides it likes its new channel better? Isn’t that how rivers change courses—during floods?