Outside of levee protections, structures are all on piles above the flood elevation, so floods literally go under the house. Inside levee protections, as the s

Outside of levee protections, structures are all on piles above the flood elevation, so floods literally go under the house. Inside levee protections, as the system currently exists, it doesn't, so houses have to have sand pumped under them occasionally to fill gaps left by subsidence. The house is on piles, so it remains in place.