Evaluation of coastal erosion susceptibility in Santa Catarina island’s beaches

Abstract

The assessment was based on geoindicators evaluated in situ, Digital Elevation Models, and surface maps of distances from the coastline were used as geoindicators of susceptibility. Interpolation techniques, fuzzy logic functions, and map algebra were applied. The highest susceptibility was observed on the southern sector of the Ingleses Beach, which presented severe coastal erosion, with absence of dry beach, foredunes and interior dunes, and presence of many seawalls. The lowest susceptibility occurred on the west sector of Pântano do Sul Beach, where the dry beach was wide, fore dunes were above 2 m, well vegetated and established. The Armação and Pântano do Sul Beaches also had sectors with very high susceptibility, while Morro das Pedras Beach varied from medium to high susceptibility. It was evident that the most susceptible areas were related to inadequate occupation, with houses and buildings over or immediately behind the foredunes, with minimum setback. The use of geoindicadores and spatial analysis techniques yielded a rapid and efficient assessment of the beaches and can be used as management tools for assessments of other areas and for coastal monitoring.