Resumen de Impacto sobre el sedimento de una regeneración artificial sumergida de playas:: El ejemplo de Terschelling (Holanda)

• The nearshore zone of Terschelling is characterized by two or three breaker bar systems. The disposition of the bars is nearlly parallel to the shoreline. The natural sediment distribution shows a fining gradient from the shoreline up to 6 m depth and, at this point, the sediment becomes coarser again. The littoral morphology and sediment distribution in the Island of Terschelling were disturbed by a shoreface nourishment carried out in the central part of the island during the period April-September 1993. The sedimentological impact of this nourishment is investigated in this work during the period March-1993 to October 1994 in order to increase our understanding of coastal processes. The shoreface nourishment filled up the trough between the middle and outer bars. Six months after the nourishment was completed, a new trough is being eroded at the same position as the previous one and the morphological profile is comparable again with the morphology in the pre-nourishment conditions. The sediment supplied caused a coarsening (20-40 microns) of the sediment in the zone directly affected by the nourishment. Six months after the nourishment, the grain size distribution is nearly the same as the original and no significant effects of the nourishment are recognized in the median grain size. Results of the sediment analysis from the coastal zone of Terschelling indicate that the shoreface nourishment only has a short-term impact. This implies that the supplied sediment is quickly dispersed and mixed with the original deposits