Efecto erosivo de los temporales del invierno 1995-1996 sobre la playa de Mazagón (Huelva, SO de España): influencia de las construcciones costeras

Abstract

The Mazagón Beach, one of the most important touristic localities of the Huelva Coast, is located to the East of the mouth of the Tinto and Odie! Rivers. Since the construction of several harbours infrastructures in this mouth, the beach has experimented a process of dynamic inestability which results in a very high erosion rate, which is increased during stormtimes. Throughout 1995 and 1996 some important storms damaged some touristic buildings closest to the coastline. The effects of these storms have been studied by carrying out sedimentological and topographical analyses. These provide evidence that the sand volume eroded in the analyzed zone during the study period, reached up 45,796 m3 which distributed in the whole study surface (36,778 m2) result in a 1.25 m3/m2 sediment deficit. Contrarily, during the fair-weather periods, a ridge-and-runnel system dynamics transports sand to the higher zone of the foreshore, this meaning that just vertical shifting of the sand is realized with no increase of total sand volume in the area. The erosion is reflected in the sediment sequence as an erosive surface, with a residual lamina of coarse material and/or heavy minerals cutting the ridge-and-runnels sequence. The cause of this erosion has been interpreted by using wave-refraction maps, because this coastal sector is located in a swash divergence zone, regardless 0f the provenance direction of the waves.