Modeling 3-Dimensional Sediment Transport Processes in Delaware Estuary

The Estuarine Turbidity Maximum (ETM) zone is classically thought to be an area of intense sediment deposition that is generated by near-bottom convergence due to an along-channel baroclinic pressure gradient. Within this framework, estuarine sediment transport has typically been described in terms of along-channel processes. However, recent studies have shown that lateral circulation contributes significantly to transport processes and that the ETM zone has important 3-dimensional structure, with differing processes dominant on the flanks and channel.

This study utilizes a Regional Ocean Modeling System (ROMS) circulation and sediment model of Delaware Estuary to explore the importance of lateral sediment processes. Coupled with observations from a mooring array deployed in 2011 within the ETM, the model offers insight into the mechanisms that move sediment between the channel and flanks. A decomposition analysis isolates the tidal pumping and mean advection terms, revealing that the mean circulation is the primary control on lateral sediment transport. The spatial variability in both lateral and axial sediment transport emphasizes that the trapping efficiency of the ETM is closely related to its 3D structure.