Shoreline change rates along Samborombón Bay, Río de la Plata estuary, Argentina

BACINO, GUIDO L.; DRAGANI, WALTER C.; CODIGNOTTO, JORGE O.; PESCIO, ANDRÉS E.; FARENGA, MARCELO O.

ESTUARINE COASTAL AND SHELF SCIENCE

ACADEMIC PRESS LTD-ELSEVIER SCIENCE LTD

Año: 2020 vol. 237

0272-7714

Samborombón Bay is an extensive microtidal wetland located at the outer Río de la Plata estuary. Shoreline change rates (erosion or accretion) were quantified at six control areas disposed along the coast of the bay. Digital ShoreAnalysis System 4.3 (DSAS) was used to process aerial photographs and high-resolution satellite images. Total periods (last 50 years) and recent periods (last decade, approximately) were considered for the analysis of theevolution of the shoreline. Erosion and accretion rates increased in five of the six areas during the last decade. The alongshore (PlN) and the incident (Pi) wave energy fluxes were computed from numerical simulations of waves.Highest annual mean Pi were observed at the southern and northern sectors of the bay, and lower values were obtained at the center of the bay. Annual mean PlN shows a convergent pattern in Samborombón Bay. Some differences in the annual mean PlN were detected between adjacent locations. These differences could generate a slight divergence in PlN producing mild coastal erosion. Pi presents positive trends in almost all the bay. On the contrary, PlN only presents a significant trend in the south of the bay. Then, while the capability of erosion (Pi) is increasing, the capacity of transport (PlN) is quite stable along the coastal area of the bay. Finally, the hydrosedimentary processes at the coastal area of Samborombón Bay were interpreted by means of a simple conceptualmodel which includes internal and external sources of sediments.