A 100-year flood does not refer to a flood that occurs once every 100 years, but to a flood level with a 1 percent or greater chance of being equaled or exceeded in any given year. Areas between the 100-year and the 500-year flood boundaries are termed Moderate Flood Hazard Areas. The remaining areas are above the 500-year flood level and are termed Minimal Flood Hazard Areas.
FLOOD, 100-YEAR
Meaning of FLOOD, 100-YEAR in English
Environmental engineering English vocabulary. Английский словарь экологического инжиниринга. 2012