In this video from NOVA, Watch as the U.S. Army Corps of Engineers engages in " beach nourishment," to replace the sand lost in Coney Island and Luna Park during Hurricane Sandy. They replace 3.5 million cubic yards of sand in a five–mile area. A dredging barge anchors near a good source of sand offshore and pumps it through pipes submerged under water onto the beach. Bulldozers spread and smooth things out and place it to the proper grade. The cost may be prohibitive in the future, so the authorities will have to consider other methods.