Susceptibilidade à ocorrência de inundações no município de Dona Francisca – RS: uso de média ponderada e geoprocessamento para análise ambiental

Abstract

This work aimed to identify the areas susceptible to the occurrence of flooding in the municipality of Dona Francisca - RS, based on environmental analysis and Geoprocessing techniques. For the mapping of soil use and cover, SPRING software version 5.2.7. Regarding the variables, geology, geomorphology, soil typology, slope and hydrography, the software Quantum GIS (QGIS) version 2.14.3 was used; while for the environmental analysis of areas susceptible to flooding, the Vista SAGA 2007 software was used. In the Vista SAGA software, the weights (100%) and the scores of 1 (very low susceptibility) were assigned to 10 (very high susceptibility) to the different classes of thematic maps; the thematic maps were then crossed using the weighted average algorithm. The results showed that the areas of very high and high susceptibility to flood occurrence are located in the western and southern regions of the municipality; associated with the slopes of 0 to 8% (flat and gently undulating relief), soils Eutrophic Plasters, with geomorphological features Aluvio-coluvionar Plain and Jacuí River Depression. I n these areas the urban zone and agricultural activities such as the cultivation of rice are still outstanding, which is quite expressive in the lowland areas. As for the areas of medium, low and very low susceptibility, these were more representative in the study area, being located in the central region, east and north. In these areas, the slopes found were 8% to> 45% (wavy relief to hilly), soils typified as Planosols Eutrophic Abstracts and Eutrophic Lithium Neosols. As for geomorphology and geology, the Campos Gerais Plateau, Serra Geral and the easy Gramado and Botucatu formation were evidenced respectively. The use of geotechnologies allowed the environmental evaluation of the data obtained by different thematic maps, which allowed to have an integrated vision of these aspects of great relevance for the analysis and mapping of the areas susceptible to flooding.