One-Hundred Year (100-Year) Floodplain 1
One-Hundred Year (100-Year) Floodplain 1 : The land area adjoining a river, stream, lake, or ocean which is inundated by the 100-year flood, also referred to as a flood having a 1 percent chance of occurring in any given year. The 100-year flood is the regulatory (base) flood under the NFIP. (FEMA, Definitions of Terms, 1990)