According to a study by the National Academy of Engineering and the National Research Council, levees and floodwalls surrounding New Orleans—no matter how large or sturdy—cannot provide absolute protection against overtopping or failure in extreme events. Levees and floodwalls should be viewed as a way to reduce risks from hurricanes and storm surges, not as measures that completely eliminate risk. For structures in hazardous areas and residents who do not relocate, the committee recommended major floodproofing measures—such as elevating the first floor of buildings to at least the 100-year flood level.