They /should/ have been squeezed, but flood plains and marshes aren't hard barriers to building like water (though you can do reclamation but that's also pretty

They /should/ have been squeezed, but flood plains and marshes aren't hard barriers to building like water (though you can do reclamation but that's also pretty expensive). They're places you shouldn't (or should be very careful about about) build in but they're not places you can't build in period.