ü Levees and floodwalls can protect a building and the surrounding area from inundation without significant changes to the structure if the design flood level is not exceeded.
ü There is no pressure from floodwater to cause structural damage to the building.
ü These barriers are usually less expensive than elevating or relocating the structure.
ü Occupants do not have to leave the structure during construction.
ü This technique cannot be used to bring a substantially damaged or improved structure into compliance with floodplain development standards.
ü May violate floodplain development standards, particularly in floodway locations, by causing obstructed flow or in increased flood heights.
ü Failure or overtopping of a levee or floodwall results in as much damage as if there was no protection (or more).
ü May restrict access to the structure. If human intervention is required for closures, there must be adequate warning time.
ü May be expensive.
ü For buildings with basements, hydrostatic pressure from groundwater may still cause damage.
ü Local drainage can be affected, possibly creating water problems for others.
ü Interior drainage must be provided.
ü Levees require considerable land area.
ü Require periodic maintenance.
ü No reduction in flood insurance premiums.
ü Do not eliminate the need to evacuate during floods.