Miami too. The city is build on porous limestone. No amount of levees, seawalls, or dams will save it.

Right, for Miami, you might want kwelschermen (or a variant thereof: deep impermeable cutoff walls, doesn't need to be concrete, can be made by clay injection too) , californian style water injection, locks that reject salt water. Different place, different geology, different tools. No place is exactly the same.

Thing is I figure you need some form of water board to manage it. A political entity that's all about "here we are and here we stay". Once they're set up they're pretty reliable (there's one that's still paying interest on a 370-year old bond https://www.youtube.com/watch?v=cfSIC8jwbQs )

Put dikes around it, make channels to collect the seepage, pump water out of channels over the dikes into the sea. Problem solved in the same way the Netherlands has been solving this problem for many centuries. The pumps can run on solar power with some diesel backups for when the sun doesn't co-operate. As long as the system is kept in good shape and the channels are kept open Miami can lie several meters under sea level without the need for further action. The house I lived in in the Netherlands was at -4.5 m below sea level, it is still standing and will remain doing so if history can be a guide.

Yet those in the know keep building there. Weird isn’t it?

Engineers will find a solution, they always do if there is sufficient motivation.

what are you talking about, miami is actively investing in fixing this problem

https://www.nbcmiami.com/investigations/miami-beach-resilien...