Ebb-tidal-delta and coastal erosion in the beaches of Atalaia Velha and Mosqueiro, Aracaju, SE

Abstract

The shorelines associated with river mouths are highly unstable environments due to the strong influence of waves, tides, currents, river discharges and the dynamics of ebb-tide-deltas. This work aims to identify the mechanisms responsible for changes occurring in shoreline configuration of the Atalaia Velha and Mosqueiro beachs , located in Aracaju, Sergipe. The methodology consisted of shoreline and the ebb-tidal-delta multitemporal mapping at the ArcGis 9.3.1 software. For mapping, historical maps of 1894, 1914, 1927 and 1946; aerial photographs of 1965, 1971 and 1984, and satellite images of 2003 and 2008 were used. From the analysis of historical maps it was possible to characterize the process of evolution of sandbanks and morphological changes in the shoreline of Sergipe river mouth. The shoreline multitemporal analysis showed that in the 1965-2003 period, occurred shoreline’s progradation, and from 2003 to 2008 occurred shoreline’s erosion in Atalaia Velha beaches. At Mosqueiro’s beach occurred shoreline progradation from 1965 to 1984 and erosion in the subsequent period, from 1984 to 2008. This work serves as subsidies to urban and environmental planning in the studied area.