|Morphology and hydrodynamics of a macrotidal ridge and runnel beach under modal low wave conditions = Morphologie et hydrodynamique d'une plage macrotidale à barres et à bâches dans des conditions de houle basse|
Sipka, V.; Anthony, E.J. (1999). Morphology and hydrodynamics of a macrotidal ridge and runnel beach under modal low wave conditions = Morphologie et hydrodynamique d'une plage macrotidale à barres et à bâches dans des conditions de houle basse. J. Rech. Océanogr. 24(1): 25-31
In: Journal de Recherche Océanographique. Union des Océanographes de France: Paris. ISSN 0397-5347, more
Beach morphology; Coastal morphology; Ridges; Runnels; ANE, Belgium, Belgian Coast [Marine Regions]; Marine
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Wave and current measurements were carried out over three days in the course of a week-long survey of the topography and bedforms of a macrotidal ridge and runnel beach in Leffrinckoucke, northern France during modal low wave energy (Hb < 0.25 m) conditions. The beach may be divided into three zones; a low-gradient (tanB = 0.008) lower beach dominated by longshore currents essentially driven by tides under the low wave energy conditions, and mid- and upper beach zones characterised by steep-faced ridges (tanB = 0.02-0.035) whose morphology and plane beds reflect both wave breaking processes and cross-shore current activity related to both tides and waves. Field observations show that wave behaviour near breaking is strongly affected by local depth variations over the ridge and runnel topography during the vertical tidal excursion. The runnels also play an important role in channelling swash bores and tide water alongshore. This gives rise to abundant current ripples and meso-scale bedforms in the runnels and the lower parts of the ridges. Short-term macro-scale changes involving overall ridge and rrunnel morphology are insignificant under the low wave energy conditions that prevailed during the experiment.