Although wetlands and floodplains are often considered synonymous, they have distinct differences.
Floodplains are land areas susceptible to partial or complete inundation from the overflow of inland or tidal waters, or from the unusual and rapid accumulation or runoff of surface waters from any source. Special Flood Hazard Areas (SFHA) are those areas of the floodplain subject to flooding by the 1% annual chance storm event. In the SFHAs, flood insurance is required by mortgage companies under federal law, and the County assures that all new construction complies with the Flood Damage Prevention Ordinance.
On the other hand, the federal Clean Water Act defines wetlands as those areas that are inundated or saturated by surface or ground water at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs, and similar areas. Wetlands are regulated by the U.S. Army Corps of Engineers.
While they often coexist, not all floodplains are wetlands, and not all wetlands are floodplains. The terms are not interchangeable.