Análise das áreas propensas a inundação e a expansão urbana no município de João Pessoa, Paraíba, Brasil

Abstract

Disasters caused by natural phenomena have gained space in the sciences worldwide due to the increase in their intensity and frequency. Urbanization and flooding in cities play a cyclical role in construction of disaster risk, so the general objective of this research was to identify areas prone to flood risk and their connection with the process of evolution of the urban spot in the city of João Pessoa, Paraíba. The methodology was divided into two stages. In the first, areas susceptible to flooding were identified using the Height Above the Nearest Drainage Model (HAND) with Digital Elevation Models (DEM) of three spatial resolutions and different spatial approaches. Subsequently, mapped areas were classified according to an order of priority of risk reduction (very low to very high). The second stage consisted in analyzing the urban expansion in the city during the period from 1990 to 2018. The best results appeared when using a 5 m x 5 m DEM resolution and a spatial approach considering the João Pessoa hydrographic basins. The model was validated based on local visits. The hydrographic basins that presented a higher percentage of their areas with “very high” order to prioritize actions to reduce flood risk were Marés-Sanhauá, Jaguaribe and Gramame river basins. Evaluating these data and the exposed population estimate, which was calculated considering a proportion between the area of each basin and the mapped area, it was found that there was a greater concentration of neighborhoods with higher percentages of exposed population (above 20.1%) in the Marés-Sanhauá and Jaguaribe river basins. However, better infrastructure conditions in some neighborhoods provide greater adaptation and coping than others. When analyzing the period from 1990 to 2018, the Cuiá river basin showed prominent urban expansion. In 2018, Jaguaribe, Marés-Sanhauá and Cuiá were the most urbanized river basins. Analyzing in an integrated way, the Jaguaribe and Marés-Sanhauá river basins were those with the greatest overlap of urbanized areas and areas with a very high degree of priority for risk reduction actions. Thus, preventive and adaptive actions are recommended in the most priority areas of the Jaguaribe, Marés-Sanhauá and Cuiá river basins.