ABSTRACT: The dynamics of the large dune systems adjacent to lowlands and to the oceanic coastline in Uruguay is likely to be affected both by sea level rise and wind circulation patterns. A simple eolian sand transport model, which relates wind friction, frequency and direction to sand transport, was used to estimate annual sand transport as a measure of the impact of potential climate changes on the stability of dune systems and beaches. The model was adjusted to local conditions using real wind-matrix and eolian-transport data from the past 5 decades. The climate change scenarios considered assume a positive or negative 10% change in the frequency of the South Atlantic Anticyclone winds, since its position determines the near-surface wind circulation pattern. Results obtained at the Cabo Polonio study area indicate that, in the medium and long term, coastal recession is likely to occur due to a decrease in coastal dunefield activity induced by changes in wind pattern. It was also observed that, should current anthropogenic impact in the area remain unchanged, the situation would be equally serious even under a non-climate-change scenario. This is due to the fact that the forestation process that has taken place over the past 20 yr has caused the immobilization of a significant portion of the dune system, preventing natural sand transfer to the coast. In recent years a still insufficient deforestation effort, intended to stop coastline recession, has taken place.

KEY WORDS: Climate change · Coastal dynamics · Coastal dunes · Forestation

Published in CR Vol. 9, No. 1-2 (1997) on December 29
ISSN: 0936-577X. Copyright © Inter-Research, Oldendorf/Luhe, 1997