Influência das barras transversais na variação da linha de costa em praia tropical de baixa energia

Abstract

A series of transverse bars have been identified and mapped on low-energy tropical sandy coast bordered by natural obstacles on the foreshore under a regime of semi-diurnal tides. The low wave heights coming from the SE quadrant generate a longitudinal transport towards SW-NE. The multitemporal mapping of medium (2007-2017) and short term (2017-2018) of the bars and the shoreline was made using satellite and orthomosaic images derived from an Remotely Piloted Aircraft System (RPAS). The rate of change of the shoreline was calculated using the Digital Shoreline Analysis System (DSAS) extension. The study area was divided into three sectors: north, central and south. Five preferred groups of bars were observed depending on the angle formed between the ridge and the shoreline. Transverse bars occur in a greater proportion (> 10) in the central and northern sectors. Moreover, the erosion process predominated in the southern and central sectors and the deposition process predominated in the northern sector. Possibly, the waves and longitudinal transport removed the sediments from the southern sector and transported them to the northern sector, depositing them due to the shadow zone generated by the reef limestone. The analysis of the interaction between the beach and the transverse bars is essential for understanding modern coastal environments and coastal zone management.