It's worth remembering that many of these places were settled before electricity was even an option. The Tennessee River Valley was not settled in the 1960s. Many places prone to occasional flooding have compelling reasons to be settled. Arable land, navigable rivers, and more.
Choosing only to settle in places without flooding (or any other natural disaster) and with infrastructure already built out is what some might characterize as unreasonably limiting.
> Sustainability at all costs has its own costs
You know what else has its own costs? Choosing to live in a place with flooding and without electricity. Same as following poor farming practices.
You can't take bad decisions from others and use shuffle the responsibility onto the environment. "Oh looks like we can't do the sustainable thing because then we'd have to deal with the consequences of our own actions."