SAR Applications for Coastal Purposes: Bathing Water Quality in Mar del Plata and Sea Floor Mapping in Miramar, Argentina

ISLA, FEDERICO; MÁRQUEZ, JORGE; BERTOLA, GERMÁN; RUIZ BARLETT, E.; CORTIZO, LUIS; URRUTIA, A.

Buenos Aires

Simposio; 29th International Symposium on Remote Sensing of Environment; 2002

UBA

ERS 2 Synthethic Aperture Radar (SAR) images have been used, combine-cl to other remote sensing techniques, to monitor surface water quality at the sewage discharge of Mar del Plata city and to map the submerged rocky outcrops from the nearshore zone of Miramar city.Mar del Plata is a touristic city where the water quality for bathing purposes of the northern beaches is conditioned to the discharge of the sewage disposal (the pipeline is broken at the beach). In order to plan the future pipeline disposal a study about the inner shelf dynamic and its simulation was contracted. To validate field data (water-quality parameters and bacteria decayment profiles) and modeling outputs (Aquasea model from Vatuaskill consultants), weekly surveys were performed by the means of oblique photographs (panchromatic film) taken from a small aircraft. As another validation method, an ERS2 SAR image from January 30, 1999 was used to estimate the extension of the sewage plume regarding the contrasting response in the surface roughness of the outfall plume and the coas1al waters (different texture induced by waves).Miramar is another touristic city where the beach widths have decreased due to natural erosion triggered by the forestation of the dunes that nourished those beaches. Groyne fields tried to assure the amount of sand necessary for the touristic batfong facilities (se-aside rendezvous) but there is still erosion of the nearshore areas. Beach nourishment is forecasted as the only possible solution for that beaches that minimize impacts on the long-shore drift to the north. ERS2 SAR images (January 30, l 999) from that submerged areas "reflect" a rocky seafloor (it is known that for certain dynamic conditions of the sea SAR images indicate the water surface modulation of the bottom). A side-scan survey using a 100 kHz transducer (Klein Towfish 422S) confirm that the bottom is composed of siltstone with caliche levels, and that there are some veneers of very fine sand composing locally ribbon fields.