S.E. Missouri farm land is among the richest on earth already. Until the Little River Drainage District drained the land around 1900, most of it was swamp.
The Delta is a wet place. The only levees they should have should be around the urban areas. Elevated earthen causeways can be built through the area to allow for transportation, but stopping and channeling the flood zones of the rivers in the Lower Midwest is as unwise today as it was nearly two centuries ago when they started doing that.