Vulnerabilidade socioambiental a inundações: estudo de caso de uma sub-bacia no Sul de Minas Gerais

Abstract

Due to the combination of extreme precipitation and/or rainfall for consecutive days in landscapes dominated by plains and narrow valley bottoms, large areas of the Brazil southeast and south regions are naturally susceptible to flooding. The Ribeirão José Pereira sub-basin, located in the south of Minas Gerais, more specifically in the municipality of Itajubá-MG, is one of these areas, suffering from floods aggravated by interventions in the natural course of the stream. In a great lack information context about the vulnerability of the population exposed to risk, the present work aims to analyze this aspect through the development and spatialization of a socio-environmental vulnerability index for the sub-basin studied. The methodological procedures consisted of: literature review and georeferenced data collection; thematic maps elaboration of the variables, using geoprocessing; influence evaluation of flood conditioning factors on flood susceptibility, applying the AHP (Analytic Hierarchy Process) method; influence evaluation of social, economic and demographic indicators on social vulnerability, through the AHP method; variables aggregation and preparation of final maps; and results analysis. The final socio-environmental vulnerability map to floods showed that 87.46% of the sub-basin has very low/low vulnerability, 10.09% medium vulnerability and 2.48% high/very high vulnerability. The results showed concentration of high vulnerability areas in the urban perimeter, where there is a high percentage of soil sealing and the highest population density indices. The study of the sub-basin social indicators, in turn, showed a trend towards rural areas with high social vulnerability, while it evidenced the existing social differences in the urban perimeter of the sub-basin. It is understood, therefore, that the developed index can provide information at the local and regional level of the populations that need more attention from the public authorities, either because they are in a socioeconomic vulnerability situation, or because they present a high degree of exposure to flood risks.