A floodplain is any land area susceptible to being inundated by floodwaters, such as areas adjacent to streams and rivers, coastal and tidal areas, urban runoff areas, and other low-lying areas.
Special Flood Hazard Areas are identified on Flood Insurance Rate Maps. They are areas where the National Flood Insurance Program's floodplain management regulations are enforced and where the mandatory purchase of flood insurance applies.
Special Flood Hazard Areas are designated on Flood Insurance Rate Maps as zones. The 1% annual flood chance (100-year flood) is an area which may be inundated by a flood event with a 1% chance of being equaled or exceeded in any given year. It is shown as Zone A on Flood Insurance Rate Maps.
Flood zones are defined by type, depth, and frequency of flooding. The 500-year floodplain is shown on Flood Insurance Rate Maps as Zone X shaded. Areas subject to ponding are shown as Zone C. Coastal hazard flood zone is mapped as Zone V. These areas flood like Zone A, but are subject to wave actions.