So why, you might ask, are there people living in New Orleans and Cairo, and that would be a good question. Cairo is in a long term state of serious decay and depopulation. Paducah and Evansville, far safer from the river's course, have taken on the burdens of human commerce in the Delta.
I don’t minimize the pain and expense of abandoning those sites but I agree, when you look at the plain facts it seems like a no brainer. Especially Cairo. According to Wiki the population is only 2,831. Come on.
An awful lot of places in the Paducah / Western KY / Southern IL area flooded this time, and quite a bit more would have if that Birds Point levee had not been blown... Paducah came very close to having their new Convention and Expo Centers flood, among many other things. Downtown Paducah is “safer” from the river than Cairo primarily because they have a better floodwall, and more $$ to keep it in good shape. Before that floodwall was built, Paducah was nearly wiped out by the 1937 flood:
http://en.wikipedia.org/wiki/Ohio_River_flood_of_1937
Paducah IS for the most part a thriving small city, but that’s not because it’s inherently safer from the river. It’s been better run than Cairo, among other things, and I do NOT mean that as a racial comment: The “better run” easily goes back to a time when Cairo was run by whites.