Terms and Definitions

Special Flood Hazard Area: The land in the flood plain within a community subject to a one percent or greater chance of flooding in any given year.

Base Flood Elevation: The water surface level of a watercourse or waterbody, referenced to an established datum, which corresponds to a flood event that has a one percent chance of being equaled or exceeded in any given year.

Floodway: The channel of a river or other watercourse and the adjacent land areas that must be reserved in order to discharge the base flood without cumulatively increasing the water surface elevation more than one foot, also referred to as the regulatory floodway.

Flood Zone Definitions

Flood Zone A: Special flood hazard area with no base flood elevation determined.

Flood Zone A1-30 and AE: Special flood hazard area with base flood elevations determined.

Flood Zone AH: Shallow flooding special flood hazard areas with depths of 1 to 3 feet and base flood elevations determined.

Flood Zone AO: Shallow flooding special flood hazard areas with depths of 1 to 3 feet and average depths determined.

Flood Zone AR: Special flood hazard areas that result from the decertification of a previously accredited flood protection system that is in the process of being restored to provide a 100-year or greater level of flood protection.

Flood Zone B: Areas between the limits of the 100-year and 500-year floods; or certain areas subject to 100-year flooding with average depths less than 1-food or where contributing drainage area is less than one square mile; or areas protected by levees from the 100-year flood.

Flood Zone A99: Special flood hazard areas to be protected from the 100-year flood by Federal flood protection system under construction, no base flood elevations determined.

Flood Zone V: Coastal special flood hazard areas with velocity hazard (wave action); no base flood elevations determined.

Flood Zones V1-30 and VE: Coastal special flood hazard areas with velocity hazard (wave action) and base flood elevations determined.

Flood Zone C: Areas of minimal flooding.

Flood Zone D: Areas of undetermined, but possible flood hazards.

Flood Zone X (shaded): Areas of 500-year flood; areas of 100-year flood with average depths of less than 1-food or where contributing drainage area Is less than 1-square-mile; or areas protected by levees from the 100-year flood.

Flood Zone X (unshaded): Areas determined to be outside the 500-year floodplain.

For more information on Flood Zones definitions, please visit:  https://www.fema.gov/flood-zones