Bathymetric controls on sediment transport in the Hudson River estuary : lateral asymmetry and frontal trapping
Citable URI
https://hdl.handle.net/1912/5585As published
https://doi.org/10.1029/2012JC008124DOI
10.1029/2012JC008124Keyword
Estuarine turbidity maximum; Lateral sediment distribution; Salinity fronts; Sediment flux; Sediment trapping; StratificationAbstract
Analyses of field observations and numerical model results have identified that sediment transport in the Hudson River estuary is laterally segregated between channel and shoals, features frontal trapping at multiple locations along the estuary, and varies significantly over the spring-neap tidal cycle. Lateral gradients in depth, and therefore baroclinic pressure gradient and stratification, control the lateral distribution of sediment transport. Within the saline estuary, sediment fluxes are strongly landward in the channel and seaward on the shoals. At multiple locations, bottom salinity fronts form at bathymetric transitions in width or depth. Sediment convergences near the fronts create local maxima in suspended-sediment concentration and deposition, providing a general mechanism for creation of secondary estuarine turbidity maxima at bathymetric transitions. The lateral bathymetry also affects the spring-neap cycle of sediment suspension and deposition. In regions with broad, shallow shoals, the shoals are erosional and the channel is depositional during neap tides, with the opposite pattern during spring tides. Narrower, deeper shoals are depositional during neaps and erosional during springs. In each case, the lateral transfer is from regions of higher to lower bed stress, and depends on the elevation of the pycnocline relative to the bed. Collectively, the results indicate that lateral and along-channel gradients in bathymetry and thus stratification, bed stress, and sediment flux lead to an unsteady, heterogeneous distribution of sediment transport and trapping along the estuary rather than trapping solely at a turbidity maximum at the limit of the salinity intrusion.
Description
Author Posting. © American Geophysical Union, 2012. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 117 (2012): C10013, doi:10.1029/2012JC008124.
Suggested Citation
Journal of Geophysical Research 117 (2012): C10013Related items
Showing items related by title, author, creator and subject.
-
Timescales of lateral sediment transport in the Panama Basin as revealed by radiocarbon ages of alkenones, total organic carbon and foraminifera
Kusch, Stephanie; Eglinton, Timothy I.; Mix, Alan C.; Mollenhauer, Gesine (2009-12)Paired radiocarbon measurements on haptophyte biomarkers (alkenones) and on cooccurring tests of planktic foraminifera (Neogloboquadrina dutertrei and Globogerinoides sacculifer) from late glacial to Holocene sediments ... -
Lateral circulation and sediment transport driven by axial winds in an idealized, partially mixed estuary
Chen, Shih-Nan; Sanford, Lawrence P.; Ralston, David K. (American Geophysical Union, 2009-12-03)A 3D hydrodynamic model (ROMS) is used to investigate lateral circulation in a partially mixed estuary driven by axial wind events and to explore the associated transport of sediments. The channel is straight with a ... -
The influence of lateral advection on the residual estuarine circulation : a numerical modeling study of the Hudson River Estuary
Scully, Malcolm E.; Geyer, W. Rockwell; Lerczak, James A. (American Meteorological Society, 2009-01)In most estuarine systems it is assumed that the dominant along-channel momentum balance is between the integrated pressure gradient and bed stress. Scaling the amplitude of the estuarine circulation based on this balance ...