What is a floodplain?

A floodplain is the land area adjacent to a stream or river channel that experiences flooding when the water level rises.

The Federal Emergency Management Agency (FEMA) defines geographic zones in floodplains according to various levels of flood risk.  These zones are mapped as National Flood Hazard Layers (NFHL) on Flood Insurance Risk Maps (FIRM).  Each zone depicts the type and severity of flooding that may occur.

The FIRM is used to determine rates for flood insurance policies and defines the higher-risk areas where regulations for building within floodplains are in effect.