The NYC mayor tried 10 years ago and was stopped by opposition politicians: https://www.msnbc.com/morning-joe/bloombergs-20b-plan-protec...
> The mayor proposed a series of strategic flood walls, surge barriers, dunes, tidal barriers, and bulkheads built around the coasts strategically, to insulate the coastal areas, as well as building codes to protect homes and businesses against flooding and infrastructure improvements to prevent power, fuel, and telecommunication outages.