The impact of storms and stratification on sediment transport in the Rhine region of freshwater influence

Flores, Raúl P.; Rijnsburger, Sabine; Horner-Devine, Alexander R.; Souza, Alejandro; Pietrzac, Julie D.. 2017 The impact of storms and stratification on sediment transport in the Rhine region of freshwater influence. Journal of Geophysical Research: Oceans, 122 (5). 4456-4477. 10.1002/2016JC012362

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Text AGU Publisher statement: An edited version of this paper was published by AGU. © (2017) American Geophysical Union. Further reproduction or electronic distribution is not permitted doi:10.1002/2016JC012362 Flores_et_al-2017-Journal_of_Geophysical_Research__Oceans.pdf - Published Version Download (4MB) | Preview

Abstract/Summary

We present measurements of along and across-shore sediment transport in a region of the Dutch coast 10 kilometers north of the Rhine River mouth. This section of the coast is characterized by strong vertical density stratification because it is within the mid-field region of the Rhine region of freshwater influence, where processes typical of the far-field, such as tidal straining, are modified by the passage of distinct freshwater lenses at the surface. The experiment captured two storms, and a wide range of wind, wave, tidal and stratification conditions. We focus primarily on the mechanisms leading to cross-shore sediment flux at a mooring location in 12m of water, which are responsible for the exchange of sediment between the near-shore and the inner shelf. Net transport during storms was directed offshore and influenced by cross-shelf winds, while net transport during spring tides was determined by the mean state of stratification. Tidal straining dominated during neap tides; however, cross-shore transport was negligible due to small sediment concentrations. The passage of freshwater lenses manifested as strong pulses of offshore transport primarily during spring tides. We observe that both barotropic and baroclinic processes are relevant for cross-shore transport at depth and, since transport rates due to these competing processes were similar, the net transport direction will be determined by the frequency and sequencing of these modes of transport. Based on our observations, we find that wind- and wave-driven transport during storms tends move fine sediment offshore, while calmer, more stratified conditions move it back onshore.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1002/2016JC012362
Programmes:	NOC Programmes > Marine Physics and Ocean Climate
ISSN:	2169-9291
Additional Keywords:	Sediment transport, Density Stratification, Tidal straining, Plume fronts, River Plume, Rhine ROFI
NORA Subject Terms:	Earth Sciences Marine Sciences
Date made live:	28 Mar 2017 08:55 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/516661

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