Hydrology, geomorphology, and vegetation of Coastal Plain rivers in the southeastern United States

Rivers of the Coastal Plain of the southeastern United States 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 hydrogeomorphic 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 hydyoperiod. Substantial sediment (and adsorbed contaminants) retention and storage through lateral and bertical accretion is common (where not heavily impacted by flow regulation) along these Coastal PI&n 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 Plain bottomlands.