Sediment Transport in the Hudson River
Work in collaboration with Dong-Ping Wang and Roger Flood
Funded by Sea Grant Award SG07026
Understanding the transport and deposition of sediment contaminants in rivers, estuaries and coastal waters is essential for local governments and citizens to identify and predict the impact due to dredging operations and coastal hazards. Common sediment transport models, such as ECOMSED and ROMS, consider only the bulk concentration of the sediment, neglecting that sediment particles have a characteristic size distribution. Since the transport and fate of the fine and coarse grained sediments are quite different, accounting for the size distribution is crucial for accurately predicting the fate of different sediment fractions and the contaminants associated with those fractions. Also, the nature of the sedimentary environment (which includes sedimentation rate and sediment morphology) plays an important role in creating benthic habitats.
We aim to improve the traditional modeling approach by taking into account the size distribution of the sediment particles and the processes that shape the size distribution: (a) transport processes such as sedimentation, turbulent diffusion and advection with the mean flow, (b) resuspension and deposition, and (c) sediment dynamics processes such as flocculation and breakup. The flocculation, in particular, plays an important role since it transfers particle mass from small sizes to larger ones. Flocculation occurs mainly due to differential settling and the impact of turbulence. In this context, the impact of turbulence on the flocculation represents a major gap in our current understanding.
Publications
F. Xu, D.-P. Wang, N. Riemer [2009] An idealized study of flocculation effects on sediment trapping in an Estuarine Turbidity Maximum over tidal cycles, submitted to Continental Shelf Research.
F. Xu, D.-P. Wang, N. Riemer [2008] Modeling flocculation processes of fine-grained particles using a size-resolved method: Comparison with published laboratory experiments, Continental Shelf Research, 28, 2668-2677, DOI: 10.1016/j.csr.2008.09.001.