Análise da vulnerabilidade socioambiental do município de Mangaratiba por técnica de geoprocessamento

Abstract

Considering the fact that to reduce the condition of vulnerability in natural systems including its people, it is necessary firstly to identify the most vulnerable parts of the territory, this study was aimed at the generation of the Environmental Vulnerability Map of the City of Mangaratiba (RJ). Practically all of Mangaratiba’s territory is part of the protected areas scheme, either of sustainable use, in the case of Mangaratiba’s APA or strictly protected, such as the State Park Cunhambebe (PEC). However, this fact does not exempt the municipality to suffer the effects of urban sprawl. The proximity to the slopes of Serra do Mar associated with a disorderly occupation are responsible for both frequent erosion and mass movement events in the region, especially in the summer when rainfall is more intense and recurrent. Therefore, the research wascarried out starting with the conceptual theoretical discussion, making use of the concepts ofrisk and vulnerability as well as the function, the role and the applicability of those concepts within the geography. The identification of the areasof greatest social vulnerability was obtained by a construction of social indicators based indata from the infrastructure census (water, sewage and litter) andIBGE’sper capita income census (Brazilian Institute of Geography and Statistics - Population Census 2010) in the municipality of Mangaratiba.These were crossed, by map algebra (multi-criteria analysis) in ArcGIS 10.0, using the following maps: Pedological, Geomorphological, Slope’s, Land Use and Occupation, and Pluviometric data; in order to identify the areas of greatest environmental vulnerability. Subsequently, it was also considered the surroundings of waterway banks, hilltops, slopes greater than 45 degrees, mangroves, amongst other things that infringe and conflict with the permanent protection areas (APP), according to the new Brazilian forest regulation(Law No. 12 651, 25/05/2012 ), which are therefore areas of highest environmental vulnerability .The generated results showed that the municipality is located predominantly in highly vulnerable environmental area, especially close to the major highways, where a considerable part of the population lives. These areas are considered to be in high-risk of landslides and floods in APP. This framework, for instance, combined with the low access of the inhabitants to public infrastructure has resulted in high environmental and social vulnerability, featuring most of the territory, hence providing a challenge to local public administration, especially in densely occupied areas both bordering and within Conservation Units