Mapping of the retrogradation and coastal vulnerability of the seashore at Barra de São Miguel County, Brazil 99 68

Abstract

It is necessary to expand knowledge regarding physical environment in order to establish rational guidelines for coastal areas use, thus, this research aimed to determine retrogradation rates and vulnerability of the seashore at Barra de São Miguel county to RSL rise, as well as to suggest building zone limits. Therefore, in loco environmental observations were obtained between 2016 and 2017. In order to categorize vulnerability level, the coast was divided into section A (A₁, A₂ e A₃) and section B. Results show that approximately 57% of the coast (Section A) is threatened, presenting high vulnerability level. In contrast, section B presented low erosion vulnerability. Retrogradation indicated that even in the optimistic scenario, retreats will be high, reaching all buildings in the section A. Section B, despite high environmental preservation level, would still exhibit retreats of 15.1m. Coastal building zone limit (CBZL) demonstrated that previous results adoption would be enough to absorb future impacts generated by RSL rise. Thus, it is valid to affirm that results obtained are important to comprehend coastal environment and could be used as a guiding source to monitoring and management of the region.