I haven't read the article yet but one thing that makes more complicated in the US is the widespread use of septic tanks. The leach field will flood before the actual surface.
Check out this map of population density: https://vividmaps.com/wp-content/uploads/2021/10/metropolita...
All those dense spots in Florida and along the Gulf are also more likely than most US urban areas to use septic tanks. That's a lot of brackish poop, clogged toilets, and environmental contamination coming in the next few decades.
Miami-Dade is full of septic tank. I think the state has about ~3M of them total. No one thought about the coastal water table when installing them, and I honestly don't know if they do even now.
See: https://www.gainesville.com/story/sports/columns/dooley/2019...
Situation is similar across the whole Gulf Coast. You really shouldn't assume any of this was rationally planned.