Floodplain Information

SPECIAL FLOOD HAZARD AREAS (SFHA) - The 1% annual chance flood (100-year flood), also known as the base flood, is the flood that has a 1% chance of being equaled or exceeded in any given year.  The SFHA is the area subject to flooding by the 1% annual chance flood.  Areas of SFHA in Graham County include Zones A, AE, AO.  The Base Flood Elevation (BFE) is the water-surface elevation of the 1% annual flood.

FEMA Special Flood Hazard Areas (SFHA)

SFHA Designation Definition
Zone X Areas determined to be outside the 0.2% annual chance of flood
Zone X (500 Year) Areas of 0.2% annual chance of flood
Zone A No Base Flood Elevation determined
Zone AE Base Flood Elevation Determined
Zone AE Floodway The flood-way is the channel of a stream plus any adjacent floodplain areas that must be kept free of encroachment so that the 1% annual chance flood can be carried without substantial increases in flood heights.
Zone AO Depth 1' Flood depths of 1 foot (usually sheet flow on sloping terrain)
Zone AO Depth 2' Flood depths of 2 feet (usually sheet flow on sloping terrain)