100-Year Flood

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A 100-Year Flood is a flood event that has 1% probability of occurring in any time period of 1 year.



  • (Wikipedia, 2016) ⇒ ttps://www.wikiwand.com/en/100-year_flood Retrieved 2016-07-02
    • A one-hundred-year flood is a flood event that has a 1% probability of occurring in any given year. The 100-year flood is also referred to as the 1% flood, since its annual exceedance probability is 1%. For river systems, the 100-year flood is generally expressed as a flowrate. Based on the expected 100-year flood flow rate, the flood water level can be mapped as an area of inundation. The resulting floodplain map is referred to as the 100-year floodplain. Estimates of the 100-year flood flowrate and other streamflow statistics for any stream in the United States are available.Areas near the coast of an ocean or large lake also can be flooded by combinations of tide, storm surge, and waves Maps of the riverine or coastal 100-year floodplain may figure importantly in building permits, environmental regulations, and flood insurance.