CONTROLS OF SEDIMENT TRANSPORT AND DEPOSITION IN AN INCISED MAINLAND MARSH BASIN, SOUTHEASTERN NORTH-CAROLINA

Sedimentation on the surface of tidal marshes is a process that is con trolled by the interactions of a complex set of variables. To adequate ly describe the patterns of sediment transport and deposition in any p articular system requires extensive sampling of biological, physical, sedimentological, and geomorphological parameters. In this study, meas urements of sediment deposition, marsh elevation, water level, total s uspended solid (TSS) loads, overmarsh current speeds, and vegetative c over were used to determine which of these factors control sediment di stribution patterns in a small marsh basin in southeastern North Carol ina. The results of this study suggest that marsh elevation exerted si gnificant control over deposition but that its effects were largely mu ted by other processes. Creek hydrology, sediment instability associat ed with areas of new creek development, plant/flow interactions, and t idal creek TSS concentrations also influenced sediment deposition in t he study area. Flow patterns, resulting from the interaction between t idal stage and marsh topography, controlled the dispersal of particula te matter across the marsh surface and contributed to significant depo sitional differences among sampling sites as a function of tidal stage . The results of this study indicate that tidal creek geometry, creek channel position, and tidal stage interact synergistically to control sediment/particulate delivery on the surfaces of tidal wetlands.