They include marshes, swamps, and similar areas found in flats, in depressions in the landscape, on slopes where groundwater emerges to the land surface, and between dry land and open water along the edges of streams, rivers, lakes, and coastlines. Together, hydric soils, hydrophytes, and the saturation of soil during the growing season indicate that a wetland is present. Surface ponding of water is not necessary for an area to be considered a wetland, and many important wetland types have variable water regimes that leave them dry for extended periods. Formal wetland definitions have been developed by several federal agencies in the United States. These definitions include considerable detail and are used for regulatory and management purposes.
Wetlands cover approximately eight percent of Arkansas' land surface.
The wetlands of Arkansas are found in diverse physiographic settings and have many unique characteristics, ultimately due to the complex geologic history of the state. The Classification and Characterization Project illustrates this diversity. The majority of Arkansas' wetlands are riverine and depressional wetlands associated with the floodplains of the Mississippi River and its major tributaries. The value of these wetlands is immense. While the Mississippi itself has been hydrologically altered by a series of levees, many of the tributaries within Arkansas support the best of the remaining floodplain forests.