Shoreline Variation and Identification of Local Erosion Geoindicators on the Brazilian Amazon Coast

Abstract

Teixeira, S.G.; Bandeira, I.C.N., and Dantas, M.E., 2021. Shoreline variation and identification of local erosion geoindicators on the Brazilian Amazon coast. Journal of Coastal Research, 37(6), 1088–1098. Coconut Creek (Florida), ISSN 0749-0208. An analysis was conducted of the change in the shoreline in the northern part of Para (Amazonian coast, Brazil) over a medium-term period. The analysis of the variation of the shoreline was carried out by tracing the spring high tide level in LANDSAT images from 1988 to 2019. With this tracing, it was possible to verify the behavior of the processes of erosion and accretion in the different morphological units (mangroves, beaches, cliffs, and rocky shores). The results show that changes in the shoreline occurred differently in the four morphological units, both in spatial and temporal scales. Regionally, the northern coast of Para showed a trend of stability between losses and gains in areas, but with a slight predominance of the accretion process. The mangroves and beaches showed periods of alternation of predominance between the processes, while in the stretches with cliffs, the smallest areas of retreat were detected. The stretches of shoreline with a rocky shore remained stable throughout the study period. The study allowed the identification of local geoindicators for diagnosis and identification of the erosion process in coastal macrotidal regions. These results can assist in the identification of areas at risk of coastal erosion, as well as in coastal management in Para State and related areas.