Variaciones espaciales y temporales de la deriva litoral, SE de la Provincia de Buenos Aires, Argentina

Abstract

El bloqueo de la deriva litoral provocó signifi cativos impactos en las costas de Mar del Plata y Necochea, Buenos Aires, Argentina. En algunos sectores, la construcción de espigones no dio los mismos resultados que tuvieron entre los años sesenta a ochenta. Se especula que la deriva litoral ha disminuido. Hubo varios intentos de estimar este transporte litoral, o al menos la magnitud de las olas y tormentas que son determinantes de ese transporte. La compilación de estimaciones dispersas sobre el tema confi rmó que la deriva potencial calculada a partir de datos de ola no se corresponde con la efectiva en relación a la disponibilidad de arena en el sistema litoral. Esta falta de arena ocurre donde se produjo un aumento en la frecuencia de corrientes rips por largo de playa.

The blocking of the longshore drift has caused signifi cant impacts along the Mar del Plata and Necochea coastline, Buenos Aires, Argentina. In certain sectors, groyne construction is not giving the same results they did in the sixties to eighties. It was speculated that potential longshore drift has diminished. Several attempts have tried to estimate this transport, or at least the magnitude of waves and storms that seem to have a signifi cant role with this transport. A compilation of scattered data about the subject confi rms a minimum drift amount of 100,000 m3/year. However, certain issues should be considered. The number of storms per year (locally called “sudestadas”) has a signifi cant weight in the northwards coastal transport. As wave statistics is completely dependent on the location where they are measured, wavebased models should be handled with much care. Groyne fi elds increase the density of rip currents and therefore are responsible for a reduction of the longshore transport. However, there are natural variations of the coastal dynamics and transport that are also explaining morphological changes that occurred during the Holocene.