Identification of the erosive and depositional sectors of the icapuí (Ce) shoreline based on remote sensing products and geoprocessing techniques

Abstract

A B S T R A C T The importance of coastal zones implies the need for continuous studies related to the monitoring of their processes. In this context, the shoreline represents one of the most dynamic features, and its variability is an indicator of erosion or coastal deposition. In order to evaluate the changing trends of the coast of the Icapuí city, located in the far east of the state of Ceará, this work involved the use of Landsat satellite orbital images, composing a 30-year time series with fiveyear intervals between each scene. The Polygon Change Method and the Digital Shoreline Analysis System (DSAS) were applied to characterize the shoreline, quantifying its variation rates and sedimentary balance in area. The total area was divided into four portions, using coastal morphology as a segmentation criterion. The results indicated the existence of three erosion and deposition hotspots, related to the Arrombado stream inlet, in the eastern sector; the Barra Grande estuary inlet, which separates the central east and west sectors; and the Ponta Grossa promontory, which conditions a shoreline inflection in the western sector. Each of these sectors has a deposition dynamic to updrift and erosion to downdrift, with prominence to the accentuated processes of retrogradation between the Barreiras de Baixo and Barrinhas beaches, in the central west sector, and the strong depositional dynamics of Ponta Grossa beach, in the west sector.