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Short‐term intertidal bar mobility on a ridge‐and‐runnel beach, Merlimont, northern France
Author(s) -
Anthony E. J.,
Levoy F.,
Monfort D.,
DegryseKulkarni C.
Publication year - 2005
Publication title -
earth surface processes and landforms
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.294
H-Index - 127
eISSN - 1096-9837
pISSN - 0197-9337
DOI - 10.1002/esp.1129
Subject(s) - intertidal zone , swash , longshore drift , geology , tidal range , beach morphodynamics , shoal , oceanography , shore , submarine pipeline , geomorphology , coastal erosion , advection , plage , sediment transport , estuary , sediment , physics , thermodynamics
Digital elevation models and topographic proles of a beach with intertidal bar and trough (ridge‐and‐runnel) morphology in Merlimont, northern France, were analysed in order to assess patterns of cross‐shore and longshore intertidal bar mobility. The beach exhibited a pronounced dual bar–trough system that showed cross‐shore stationarity. The bars and troughs were, however, characterized by signicant longshore advection of sand under the inuence of suspension by waves and transport by strong tide‐ and wind‐driven longshore currents. Prole changes were due in part to the longshore migration of medium‐sized bedforms. The potential for cross‐shore bar migration appears to be mitigated by the large size of the two bars relative to incident wave energy, which is modulated by high vertical tidal excursion rates on this beach due to the large tidal range (mean spring tidal range = 8·3 m). Cross‐shore bar migration is also probably hindered by the well‐entrenched troughs which are maintained by channelled high‐energy intertidal ows generated by swash bores and by tidal discharge and drainage. The longshore migration of intertidal bars affecting Merlimont beach is embedded in a regional coastal sand transport pathway involving tidal and wind‐forced northward residual ows affecting the rectilinear northern French coast in the eastern English Channel. Copyright © 2004 John Wiley & Sons, Ltd.