Análise da suscetibilidade à inundação no perímetro urbano do município de Cerro Azul - PR

Abstract

The municipality of Cerro Azul-PR has areas susceptible to flooding, according to a survey carried out by the federal government, which sought to identify priority locations for the implementation of actions aimed at preventing and mitigating geo-hydrological risks. In view of this, this dissertation sought to understand the susceptibility to flooding in the urban perimeter of the municipal headquarters, covering the Ponta Grossa River and its tributaries Três Barras, Quebrada Funda and Ribeirão Bonito do Chapéu. This study used rainfall and river flow data, as well as data from historical flood records and community testimonies, comprising a 24-year historical series (2000 to 2023). The rainfall data showed an average annual rainfall of 1,417.9 mm, with the rainy season, which runs from September to March, accounting for 1,016.6 mm or 71.7% of the annual rainfall. As for the river levels of the Ponta Grossa River, the highest monthly averages in the series occurred in the months of the rainy season, October, January and December, with averages of 192 cm, 189 cm and 175 cm, respectively. The average annual level was 164 cm, while the maximum level recorded was 562 cm in August 2011. Given the data, areas susceptible to flooding were delimited using the Height Above Nearest Drainage Model - HAND Model. Based on the results obtained through geoprocessing, susceptibility classes ranging from “Very High” to “Very Low” were established. Analysis of the areas classified according to their susceptibility to flooding (km2), in relation to the perimeter's population density (inhab/km2), reveals that approximately 201 inhabitants live in regions of “Very High” susceptibility. In addition, around 138 inhabitants are located in areas of “High” susceptibility, while around 149 inhabitants live in areas of “Medium” susceptibility. In areas classified as “Low” susceptibility, it is estimated that there are around 134 inhabitants. Finally, around 140 inhabitants live in areas of “Very Low” susceptibility. This means that around 764 inhabitants or 14.41% of the population of the urban perimeter of Cerro Azul live in areas with some level of susceptibility to flooding. Based on the mapping carried out and the data collected, it is important to emphasize the relevance of using Geographic Information Systems (GIS) in the context of Disaster Risk Management (DRM). The implementation of an adequate data infrastructure is essential to enable effective planning and management actions aimed at mitigating the vulnerabilities and dangers present in the territory. These efforts have the potential to contribute significantly to preventing and minimizing disaster risks, as well as reducing potential damage and losses.