A floodplain is any land area susceptible to being inundated by water from any source. It includes the floodway and flood-fringe areas.
A general and temporary condition of partial or complete inundation of normally dry land areas from the overflow of inland or tidal waters, the unusual and rapid accumulation or runoff of surface waters from any source, or mudflows which are proximately caused by flooding
The collapse or subsidence of land along the shore of a lake or other body of water as a result of erosion or undermining caused by waves or currents of water exceeding anticipated cyclical levels, or suddenly caused by an unusually high water level in a natural body of water accompanied by a severe storm, or by an unanticipated force of nature, such as a flash flood or an abnormal tidal surge, or by some similarly unusual and unforeseeable event that results in flooding.
A floodway is 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 a designated height. The floodway is the most dangerous part of the floodplain. It is associated with moving water. Development is generally prohibited in floodways.
A flood-fringe is the portion of the floodplain outside of the floodway, which is covered by floodwater during the 100-year discharge. On a Flood Insurance Rate Map (FIRM), it is the Special Flood Hazard Area (SFHA) that's outside the floodway
A base flood means the flood having a one percent chance of being equaled or exceeded in any given year. It's also called the 1 percent chance flood or the 100-year flood.
It means the operation of an overall program of corrective and preventive measures for reducing flood damage, including but not limited to emergency preparedness plans, flood control works and floodplain management regulations.
This is floodplain land subject to a 1 percent chance, or greater, of flooding in any given year (see "Base flood" above). The area may be designated as "Zone A" on the flood hazard map. After detailed rate-making has been completed in preparation for the publication of a flood insurance rate map, Zone A usually is refined into Zones A, AO, AH, A1-30, AE, A99, AR, VO, or V1-30, VE or V.
Each locality passes and enforces its regulations for designated SFHAs. Contact your locality's floodplain administrator for more information on your area's requirements.
To view Virginia's laws regarding floodplain management, see Code of Virginia §10.1-602. Click here for model ordinances for Virginia's communities. Those with questions should contact the Virginia Floodplain Management Program staff.
Those with questions should contact the Virginia Floodplain Management Program staff: