C. Corbau et al., Seasonal evolution of shoreface and beach system morphology in a macrotidal environment, Dunkerque area, Northern France, J COAST RES, 15(1), 1999, pp. 97-110
Differential maps have been digitalized and compared from successive bathym
etric and topographic surveys performed under different meteorological cond
itions from May 1992 to December 1994 in the shoreface-to-beach system of t
he 30 km long coastal area extending from Gravelines to the French-Belgian
border in southernmost North Sea. The data, which concern a low-relief sand
y coastal system exposed to a macrotidal regime with flood-driven eastward
sediment transport, have been interpreted according to meteorological, hydr
odynamical and aerodynamical characteristics.
A balanced sediment budget was observed, which contradicts previous data su
ggesting a progressive long-term erosional trend. This result indirectly un
derlines the key-role on the sedimentary budget of exceptional events such
as severe storms. The two types of erosion identified comprise the action o
f frontal waves and the combined interaction of tidal currents and wind.
Five hydrodynamical cells have been recognized along the shoreface. The cor
responding segmentation is attributed to the specific distribution of the w
ave energy along the coast due to the presence of submarine banks responsib
le for the deformation of the wave propagation.
The morphological changes of the beach depend on the tide and swell action
responsible for the construction/migration/destruction of the ridge and run
nel system.