Modelización bidimensional del transporte de sedimentos en la confluencia de los ríos Suaçuí Grande y Doce tras el desastre de Mariana–mg, Brasil1

On November 5, 2015, in Mariana (Minas Gerais, Brazil), the country’s largest tailings dam disaster occurred with the rupture of the Fundão dam. The collapse released 32 million cubic meters of tailings, excluding water, causing severe socioeconomic and environmental impacts, especially in the Doce River. Since then, numerous studies have sought to understand and mitigate the effects of the disaster. One of the strategies used to analyze the dynamics of the event has been the application of hydrodynamic models. This study assumes that tributaries can contribute to the recovery of the Doce River by supplying flows with lower suspended sediment concentrations. To assess this role, two-dimensional (2d) hydrodynamic and sediment transport models were applied to the confluence between the Suaçuí Grande and Doce rivers. The 2d hydrodynamic model adequately represented the flooded area, while the sediment transport model showed that faster flows favor erosion, whereas slower flows promote deposition. Although river confluences usually contribute to improving water quality, the Suaçuí Grande River plays a limited role due to the greater flow and depth of the Doce River.