Mapeamento de manchas urbanas de inundação a partir de modelagem hidrodinâmica em um trecho do Rio Capibaribe - Recife/PE

Abstract

Recent reports show that natural disasters, especially floods, generate significant economic losses on a global scale. In Brazil, CEPED (University Center for Studies and Research on Disasters) identifies the Northeast as the region with the highest number of occurrences 9 (37,965) between 2012 and 2023, with Pernambuco among the most affected states; in Recife, the Capibaribe River has recorded recurrent episodes of severe flooding. The application of high-resolution remote sensing for spatial and topographic characterization has become increasingly revolutionary in the field of hydrology and in studies of extreme events. In this context, LiDAR (Light Detection and Ranging) technology enables three-dimensional models with high spatial resolution, essential for accurately characterizing terrain and river channels, while numerical modeling allows the exploration of scenarios, supports planning, and guides decision-making in risk areas. Accordingly, this study seeks to evaluate the mapping of flood extents in an urban stretch of the Capibaribe River – Recife/PE through hydrodynamic modeling, based on simulated discharges generated using a hydrological model. The research integrated hydrological modeling (SWAT Plus) and hydrodynamic modeling (HEC-RAS) for flow simulation and, consequently, flood extent delineation. In the hydrological stage, soil, land use/land cover, and meteorological series were used to generate a series of simulated discharges. In the hydrodynamic stage, the simulated flows and Manning’s coefficients were applied in unsteady-flow simulations, resulting in flood extents for the intervals 2003–2006, 2010–2013, and 2020–2025, under both real scenarios (with Manning’s values varying according to satellite imagery) and hypothetical scenarios (Manning values representing dense vegetation along the entire reach). Flood extents were obtained for both scenarios across the three time intervals, showing significant differences in water depth and velocity between scenarios. For the first interval, there was a 30-centimeter difference in water depth and 0.12 m/s in velocity between the real scenario (maximum depth and velocity of 4.0 meters and 0.68 m/s, respectively) and the hypothetical scenario (maximum depth and velocity of 3.7 meters and 0.56 m/s, respectively). For the second interval, there was a 20-centimeter difference in water depth and 0.18 m/s in velocity between the real scenario (maximum depth and velocity of 4.2 meters and 0.78 m/s, respectively) and the hypothetical scenario (maximum depth and velocity of 4.0 meters and 0.60 m/s, respectively). For the third interval, there was a 20- centimeter difference in water depth and 0.20 m/s in velocity between the real scenario (maximum depth and velocity of 3.0 meters and 0.60 m/s, respectively) and the hypothetical scenario (maximum depth and velocity of 2.8 meters and 0.40 m/s, respectively).The analyses presented in this study highlight the application and efficiency of software tools in hydrological 10 and hydrodynamic studies in any region of the world, especially in areas that lack data and face significant hydrological impact challenges.