Initial Steps in Hydrological Calibration Using the Hydrodynamic Pollutant 2D model (HydroPol2D): Case Study of the Guaíba River Basin, Rio Grande do Sul, Brazil

Código

I-EBHE0123

Autores

Caline Cecília Oliveira Leite, Marília de Oliveira Felten, Mateo Hernández Sánchez, Luis Miguel Castillo Rápalo, Eduardo Mário Mendiondo

Tema

WG 1.12: Development & application of river basin simulators

Resumo

The increase in global temperature caused by climate change has significantly altered the water cycle, leading to a rise in the occurrence and intensity of extreme events such as droughts and floods. In southern Brazil, the most recent extreme rainfall events occurred between April and May 2024 in Rio Grande do Sul, highlighting the urgent need for adaptive measures to cope with the increased risk of flood events. In this sense, hydrological models coupled with hydraulic models as support become decisive tools in water management since they are capable of simulating the water transport process in a watershed. Spatially-distributed models account for more precise processes related to the water transport across the watershed and adopt better representation of flood mapping. HydroPol2D is an open-coded, fully distributed model that is diffusive flow routing and based on a cellular automata scheme. In this model, it is possible to use rainfall information from satellites and use open-access databases. This capability is beneficial in regions with sparse hydrological information. In this way, this work aimed to evaluate the HydroPol2D performance by simulating the Guaíba river watershed in Rio Grande do Sul, Brazil, within the period 2018?2023, focusing on flood events. As inputs to the model, data from open-access sources were assimilated. The Digital Elevation Model (DEM) was obtained from Copernicus, soil information from the Food and Agriculture Organization (FAO), land use and land cover from Dynamic World, and rainfall data from the PERSIANN PDIR-Now satellite. Using this information, the model generated streamflow as output data. These streamflows were compared with observed data from streamflow stations of the National Water and Basic Sanitation Agency (ANA). For the first stage of calibration of the hydrodynamic modeling with satellite information, the model shows coherent behavior regarding flood peaks. However, limitations were observed in water transport in flat areas due to the current version of HydroPol2D accounting only for diffusion simplifications and not considering the full momentum of the Saint-Venant equation. To achieve a better representation of the Guaíba basin and similar areas, future development stages of HydroPol2D will include the implementation of processes that better represent water transport in flat areas. Additionally, means of accounting for base flow will also be implemented, allowing the model to represent not only floods but also droughts.