Benavente, J., Del Río, L. Plomaritis, T.A, Menapace, W. 2013. Impact of coastal storm in a sandy barrier (Sancti Petri, Spain).

Behaviour of sandy geomorphological units under the impact of coastal storms is of great importance when studying coastal evolution in a medium- to short-term scale. In this paper we analyze the effect of storms in determining the recent evolution of Camposoto beach, a sector of Sancti Petri sandspit (Cadiz, SW Spain). Morphological and volumetric changes of washover deposits were evaluated under the effect of coastal storm series recorded during the winter 2009–2010. Several pre- and post-storm topographic surveys of the beach and foredune were performed using an RTK-DGPS, together with a topographic survey of the dune system and the washovers after that winter. The results were compared with dating from the winter 2008–2009, and with a DTM extracted from LIDAR from 2008. Moreover, changes in the area covered by the washover deposits and in the foredune morphology were evaluated by means of GIS tools on aerial photographs from 2008 and 2010. Results showed clear shoreline retreat in the study area, as well as an important impact of the 2009–2010 storm seasons over the foredunes. Changes in the morphology and dimensions of the washovers gave information about the patterns of storm-related medium-term evolution of the system. The above data were used for the calculation of thresholds of the minimum wave height capable of either activating former washover deposits or creating new washovers and foredune retreat. Based on these results we established thresholds for storms generating coastal retreat in the long-term evolution of the sandspit, as a consequence of dune erosion and overwash processes.