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.
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.
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.
publication date
Acknowledgement of products derived form this data set should cite the following: The source of the flood zones data is the North Carolina Floodplain Mapping Program. Earlier versions of these data set may exist. Data may be preliminary and not finalized until Flood Insurance Rate Maps (a derivative product) are officially approved. The user must be sure to use the appropriate data set for the time period of interest. While efforts have been made to ensure that these data are accurate and reliable within the state of the art, the NC Floodplain Mapping Program or its agent, CGIA, cannot assume liability for any damages or misrepresentation caused by any inaccuracies in the data or as a result of changes to the data caused by system transfers.
North Carolina Floodplain Mapping Program; www.ncfloodmaps.com
The NC Floodplain Mapping Program and its contractors created flood hazard areas depicting inundation under 100-year and 500-year conditions, using hydrologic and hydraulic modeling and the best available topographic and hydrologic data. Data were formatted for the Floodplain Mapping Information System. CGIA downloaded data in shapefile format from the Floodplain Mapping Information System for the current set of flood hazard areas. For distribution purposes, CGIA reprojected the data from NAD 1983 state plane feet to NAD 1983 state plane meters.
Metadata imported.
Internal feature number.
ESRI
Feature geometry.
ESRI
Internal flood area ID
unknown
flood zone
NC Floodplain Mapping Program
100-year flooding with no base flood elevation (BFE) determined
NC Floodplain Mapping Program
100-year flooding in velocity zone (coastal)
NC Floodplain Mapping Program
100-year shallow flooding
NC Floodplain Mapping Program
500-year flooding
NC Floodplain Mapping Program
100-year flooding with base flood elevation (BFE) determined
NC Floodplain Mapping Program
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.
NC Floodplain Mapping Program
unknown
unknown
unknown
unknown
unknown
unknown
unknown
unknown
Area of feature in internal units squared.
ESRI
unknown
unknown
NCCGIA is charged with the development and maintenance of the State's corporate geographic database and, in cooperation with other mapping organizations, is committed to offering its users accurate, useful, and current information about the state. Although every effort has been made to ensure the accuracy of information, errors and conditions originating from physical sources used to develop the corporate database may be reflected in the data supplied. The client must be aware of data conditions and bear responsibility for the appropriate use of the information with respect to possible errors, original map scale, collection methodology, currency of data, and other conditions specific to certain data. CGIA does not support secondary distribution of these data. The use of trade names or commercial products does not constitute their endorsement by the CGIA or North Carolina State Government.
Contact the NC Floodplain Mapping Program at 919-715-8000
20322 Mail Service Center
301 N Wilmington St, Suite 700