Wind-wave climate change and increasing erosion in the outer Río de la Plata, Argentina

Abstract

The coastal area of Samborombo´n Bay ends in a short cliff which, during the last decades, has been undergoing an increased retrogression of approximately 8.2 m decade1 . The aim of this paper is to investigate whether this accelerated erosion can be related to an apparent wind-wave climate change, which has been recently reported for the Rı´o de la Plata region. A numerical study with SWAN wave model for the period 1971–2005 drives to positive trends in the frequency of occurrence and heights of waves propagating from the E and ESE. Particularly, the number of cases of high waves from those directions displays a significant increment. In addition, previous papers have reported an increment of the frequency, height and duration of the storm surges in the Rı´o de la Plata, so as a rise of the mean sea level in the region. It is concluded that the combination of those three factors acting together constitutes a powerful and effective mechanism which is likely responsible for the observed increasing erosion in Samborombón Bay.