How are the floodplain maps developed?
Once the 100-year (1% chance) flood elevation is determined, the flood elevation is then plotted on a topographic map (a map which shows ground elevations referenced to mean sea level). The accuracy of the floodplain maps will depend on the accuracy of the topographic maps. The floodplain maps are only a guide as to whether or not a parcel is located in the floodplain. The most accurate method of determining the location of the floodplain requires an elevation survey to be done by a licensed land surveyor or a professional engineer.
