If, as we expect, flooding in some places is to become more common and more severe, with more extreme storms and rising sea levels, then the moving of human habitat to safe and dry locations will soon become a pressing need. We do have an example, and it was initiated by the residents - not the authorities.
This summer, the flooding in the American Midwest became ridiculous. Even towns that had been willing to put up with the threat of a hundred-year flood possibility got more than they'd bargained for. But one town was high and dry and feeling pretty good about itself. It had dodged the bullet by moving to a higher elevation 25 years ago.
Soldiers Grove, Wisconsin, a village of over 600 residents, had been flooded by the Kickapoo River 6 times in 60 years. The straw that broke he camel's back was the flood of 1978. The town had already purchased some hilltop land nearby, and with the impetus of the flood behind them, the town leaders began applying for government funding for building a new version of the town where the floods could not reach.
Joe Romm of Climate Progress was involved in this project, where the new town was mandated to include active and passive solar features as part of the conditions for funding. Below are pictures of the original business district of Soldiers Grove and the current DRY and solar district.