Análise multiescalar da distribuição espacial de cicatrizes erosivas aceleradas na Bacia do Rio Sacra Família (RJ)

Abstract

This dissertation had as object of study the accelerated erosive scars - ravines and gullies - present in the surroundings of the urban nuclei of the Sacra Família river basin. The objective of this research was to analyze, from different scales, the spatial distribution of these scars and to identify the environmental determinants related to their triggering. Through the use of Geoprocessing, thematic maps of possible physical, soil use and vegetation cover factors were elaborated, capable of contributing to the origin of ravines and gullies in the study area. The use of geographic information systems also enabled multicriteria analysis to generate a thematic map of environmental fragility, as well as plots of spatial coordinates, definition of areas and influence (buffers), planimetry and other functions. As a result, slope erosion, strong drainage control, structural lineaments and lithology of the rocky substratum and associated soils -latosols and argisols- were identified as conditioning factors of erosive scars. The anthropic action is related to the presence of ravines and gullies near the urban centers, especially in the municipality of Mendes, areas that underwent extensive deforestation to give way to buildings, roads, mining areas, among other uses. The Permanent Preservation Areas and the marginal protection strips of the rivers were also mapped, which showed that many scars are located in areas that should be destined for environmental preservation