Caracterização física e suscetibilidade aos processos erosivos do município de Ilhéus-Bahia

Physical characterization and susceptibility to erosive processes in the municipality of Ilhéus-Bahia

Abstract

Analyzing susceptibility provides the basis for risk prevention policies. The objective was to characterize the environmental conditions of Ilhéus that contribute to erosion processes. In addition to assessing the susceptibility of slope, geology, soil, rainfall intensity, coverage, use and occupation factors and identifying areas at risk by creating a database containing classes and values of stability/vulnerability to erosion. To develop the research it was necessary to collect bibliographic data; treatment of digital images for the map of slope, geology, soils, and land use, occupation and cover using geoprocessing techniques via GIS, in addition to average annual precipitation values (mm) and duration of the rainy season (months) ; it involved analysis based on the Crepani methodology (2001), the degree of stability of the environmental conditions, combined with the weights of the environmental conditions by the AHP Calculator (SAATY, 1991); creation of a multicriteria equation to generate the final map. The results indicate the characterization of the environmental constraints and their degree of stability, in addition to the areas of very high, high, medium, low and very low vulnerability to erosion processes produced with the integration of the mappings. Medium to very high vulnerability was obtained in 19% of the studied area, and very low to low vulnerability adds up to 82%.