Storm Surges and Morphodynamics along the East Buenos Aires Coast, Argentina

SCHNACK, ENRIQUE; POUSA, JORGE; BERTOLA, GERMÁN; ISLA, FEDERICO

New York

Otro; 2003 Annual Meeting of the Association of American Geographers, Paper Session: Dynamic Coasts; 2003

Association of American Geographers

The east Buenos Aires coastline (about 150 km long) exhibits two morphodynamic types. To the north of Mar Chiquita lagoon inlet, the coast is structurally accretionary. Southward, and down to Mar del Plata, the coast is typically erosive. Except for the southern tip, which is characterized by low cliffs (late Cenozoic) or hard rock exposures (early Paleozoic), most of the coast Is a tow-lying sandy barrier, with extensive dune fields. Extratropical storm surges ("southeastersn), coupled with strong winds from the south or southwest, high water levels and enhanced wave energy frequently affect the whole Argentine coast, as well as the Rio de la Plata shores. In the study area, storm surges cause dramatic changes in the beach profile and a significant coastal retreat, particularly in areas of intensive human intervention, mainly associated with summer tourism (beach sand mining, urbanization, dune depletion and coastal constructions). Coastal retreat values between 1-2 m/y have been determined at several localities (e.g. Pinamar, Santa Teresita, Las Toninas), with a maximum rate of about 5 m/y measured for Mar Chiquita beach. At Mar del Plata (the closest tide gauge for reference), a filtered series of mean annual sea levels over a 22-year period shows a trend of + 1.4 mm/y. Due to the nature of the sandy barrier, this increase in sea level would appear to play a secondary role in coastal erosion, if compared with the combined influence of storm surges and human intervention. However, an acceleration of sea-level rise and an increase in storm frequency under current predictions for future climate change may result in the exacerbation of the ongoing erosion processes