Stream Channelization and Swamp Formation in the U.S. Coastal Plain

Most of the major rivers and their largest tributaries in western Tennessee were channelized during the 1950s and 1960s to reduce floods. Channelization of the tributaries causes stream bed incision that destabilizes these channel systems. Headward erosion following channelization results in bank instability and collapse that produces large quantities of sediment. This sediment is transported downstream eventually clogging river channels. These channel blockages back-up water on lower floodplains creating, in some cases, large swamps. Lower floodplain surfaces prior to swamp formation would typically flood only during the wet winter and spring months; now they are often submerged for most of the year. Most bottomland trees adapted to seasonal floods cannot tolerate long-term root submersion and die within a year or two of inundation. Baldcypress is the most frequent colonizer within the swamps, rapidly occupying shallow parts of these wetlands. But many woody shrubs, small trees, and a wide variety of aqu...