(Denny Crane: "Sometimes you can only look for answers from God and failing that... and Fox News".)
Maybe they could put all the new buildings on tallllllllll pilings nailed into the bedrock--kinda like stilts. They could elevate all the old, historic buildings onto the same sort of things. You'd have to go up an escalator to get to those bars etc., unless they made cross-walks from bar to bar. Actually, after they did all this, they could just let Lake Pontchatrain go ahead and drain and--presto! Venice!