[Astromancer]

Not a terrible idea, but both New York and New Orleans are better choices by geography. New York, because Manhattan island is higher and largely made of granite, would be the best choice.

You could have a half submerged New York with the poor and the working classes, to the degree they are seperate, living in muggy, cramped, humid, overheated or clammy cold undersea slums. Which would be very cyberpunk and would probably smell of mold and mildew.