Abstract:
Field observations of flow and sediment transport in a tributary channel through intertidal
mudflats indicate that suspended sediment was closely linked to advection and dispersion
of a tidal salinity front. During calm weather when tidal forcing was dominant, high
concentrations of suspended sediment advected up the mudflat channel in the narrow
region between salty water from San Francisco Bay and much fresher runoff from the
small local watershed. Salinity and suspended sediment dispersed at similar rates
through each tidal inundation, such that during receding ebbs the sediment pulse had
spread spatially and maximum concentrations had decreased. Net sediment transport was
moderately onshore during the calm weather, as asymmetries in stratification due to tidal
straining of the salinity front enhanced deposition, particularly during weaker neap tidal
forcing. Sediment transport by tidal forcing was periodically altered by winter storms.
During storms, strong winds from the south generated wind waves and temporarily
increased suspended sediment concentrations. Increased discharge down the tributary
channels due to precipitation had more lasting impact on sediment transport, supplying
both buoyancy and fine sediment to the system. Net sediment transport depended on the
balance between calm weather tidal forcing and perturbations by episodic storms. Net
transport in the tributary channel was generally off-shore during storms and during calm
weather spring tides, and on-shore during calm weather neap tides.
Description:
Author Posting. © Elsevier B.V., 2007. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Continental Shelf Research 27 (2007): 1510-1527, doi:10.1016/j.csr.2007.01.010.
