Crescimento urbano de Três Rios: análise da ocorrência de eventos extremos e os impactos sobre as áreas de alagamento e inundação

Abstract

The urbanization process, which has intensified over recent decades, has driven the accelerated growth of numerous Brazilian cities, resulting in significant transformations in the physical environment and environmental dynamics. Among the main impacts of this process is soil impermeabilization, which reduces the infiltration capacity of precipitation and intensifies surface runoff, thereby increasing susceptibility to the occurrence of floods, inundations, and waterlogging events, especially when associated with extreme precipitation events. In this context, the municipality of Três Rios, located in the state of Rio de Janeiro, has recurrently experienced flooding and inundation episodes, phenomena directly related to the rapid and disorderly process of urban expansion.In light of this scenario, the present dissertation aimed to identify and analyze the occurrence of extreme hydrometeorological events, as well as to map and characterize areas with greater susceptibility to flooding and inundation in the municipality of Três Rios. To this end, areas historically affected by flooding and inundation were identified, along with extreme precipitation events recorded in the municipality over the last nine years. Based on the synoptic analysis of the acting atmospheric systems, it was observed that most high-intensity extreme events were associated with the influence of the South Atlantic Convergence Zone (SACZ) and the passage of frontal systems, which were responsible for high precipitation volumes over the study area.The final stage of the research consisted of applying a multicriteria analysis to identify areas susceptible to flooding and inundation, using geoprocessing tools and the Analytic Hierarchy Process (AHP) method. For the construction of the susceptibility model, variables related to land use and land cover, slope, soil type, rainfall, and hypsometry were considered, which are essential for developing the final susceptibility map. The results indicated that 0.45% of the municipal area presents very high susceptibility and 10.89% presents high susceptibility to flooding and inundation. The information produced constitutes relevant technical support for municipal public management, providing guidance for preventive actions and territorial planning strategies aimed at mitigating these events, reducing material losses, and preserving human life.