Hydrology, geomorphology and vegetation of Coastal Plain rivers in the south-eastern USA

Rivers of the coastal plain of the south-eastern USA are characteristically low-gradient meandering systems that develop broad floodplains subjected to frequent and prolonged flooding. These floodplains support a relatively unique forested wetland (bottomland hardwoods), which have received considerable ecological study, but distinctly less hydrogeomorphological study. The hydroperiod, or annual period of inundation, largely controls the development of characteristic fluvial landforms, sediment deposition and vegetation distribution patterns. Order-of-magnitude differences in wetted perimeter, width/depth, suspended sediment load and hydraulic roughness may exist between ‘dry’ in-channel seasons and the hydroperiod. Substantial sediment (and adsorbed contaminants) retention and storage through lateral and vertical accretion is common (where not heavily impacted by flow regulation) along these Coastal Plain rivers. The present chapter summarizes our current understanding of the hydrology, fluvial geomorphology, general and local sedimentation patterns, and related plant ecological patterns of these Coastal Pplain bottomlands.