A coastal wave, hydrodynamic, and sediment transport model, the coastal modeling system (CMS), is developed to conduct sediment tracer simulations and investigate the distribution of sediment plumes that originated from dredged material placement sites adjacent to Beaufort Inlet, North Carolina. Historical wave and hydrodynamic data around the inlet are assembled and analyzed. The data sets are used to drive the model. Simulation alternatives are developed that correspond to different material placement sites. The sediment transport and plume distribution are evaluated within and around the immediate vicinity of the Beaufort Inlet estuarine system for representative summer and winter months. The results of the model simulations show that high flows occur along the navigation channels and low flows occur outside the inlet in the open ocean area. Sand materials placed in nearshore sites tend to be trapped in and move along the navigation channels that enter the inlet. In offshore placement sites, the sediment plume shows slow spreading and no significant sand migration from its release locations. Simulations for the summer and winter months present different distribution patterns of sediments from the nearshore and offshore placement sites but show similar distribution patterns for each placement site.

Sediment movement due to ocean currents and waves in coastal zones and estuaries often results in navigation channel shoaling. To maintain channel navigability for commercial and military vessels and recreational boats, regular maintenance dredging is required. Each year, billions of cubic meters of sediment are dredged from the ocean floor. The disposal of dredged sediment poses a big challenge to the proper management and regulation of the dredged sediment material. Existing material disposal sites include landward and coastal areas. Because of sediment suspension and spreading, dredge and placement activities that are conducted in coastal oceans could negatively affect nearby species by changing the suspended sediment concentrations and could cause sediment deposition on the ocean bed. This study aims to develop a mathematical model to calculate waves, currents, tides, and sediment transport within a defined coastal area. Using this model, sediment that is disposed of in ocean placement sites could be traced, and the transport of the sediment material could be evaluated to determine whether these dredge and placement operations would have a negative environmental impact and to optimize the selection of ocean material disposal sites.