floodareas_fmis

Abstract:

Floodplains are low-lying areas adjacent to rivers, lakes and oceans that are periodically inundated by floodwater.  Flood zones are delineated by the NC Floodplain Mapping Program based on detailed engineering studies in selected areas and limited detail studies in remaining flood hazard areas. The detailed studies include cross sections of stream beds, elevation based on LIDAR data, and hydraulic factors and other engineering data to determine where the water would go under 100-year (1 percent annual probability) and 500-year flood conditions (0.2% annual probability).  Detailed studies produce base flood elevations (BFE) as a reference for elevating (or removing) structures in the floodplain.  Limited detail studies determine BFEs for floodplain management, but the determination calculations are less rigorous and do not require field surveys.  The inundation areas are useful for planning and emergency response purposes.

Please contact the NC Floodplain Mapping Program (www.ncfloodmaps.com)
for more information.

Purpose:

The flood hazard areas are the basis for official Flood Insurance Rate Maps under the Federal Emergency Management Agency's Cooperating Technical State program.  Data are preliminary until the maps are officially approved.

Supplemental_Information:

Key to Floodzone Values

Floodzone A = 100-year flooding with no base flood elevation (BFE) determined; zone V or VE = 100-year flooding in velocity zone (coastal); zone AO or AH =	100-year shallow flooding; zone X or shaded X = 500-year flooding; zone AE =	100-year flooding with base flood elevation (BFE) determined; zone AEFW = 100-year floodway.  The floodway is an area that includes 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 by more than a designated height.

Currentness_Reference:

publication date