Five Hundred Year Floodplain Law and Legal Definition

According to 44 CFR 9.4 [Title 44 -- Emergency Management and Assistance; Chapter I -- Federal Emergency Management Agency, Department of Homeland Security; Subchapter A -- General; Part 9 -- Floodplain Management and Protection Of Wetlands], Five Hundred Year Floodplain (the 500-year floodplain or 0.2 percent change floodplain) means “that area, including the base floodplain, which is subject to inundation from a flood having a 0.2 percent chance of being equalled or exceeded in any given year.”