Análise do rompimento hipotético da barragem da CAER no Município de Alto Alegre/RR

Abstract

This study aims to simulate the hypothetical rupture of the dam of a water reservoir located in the municipality of Alto Alegre-RR, through 'piping,' and evaluate, using an inundation map, the impacts on areas near the downstream channel of the dam. The specific objectives are to inspect the dam structure, analyze the dissipation of the flood wave generated by the rupture using a hydrological model, and provide support for the management and regulation of water resources through the generated maps. The dam is registered in the National System of Information on Dam Safety (SNISB) under code 5291, with the Companhia de Águas e Esgoto de Roraima (CAER) as its owner. The selection of the SNISB 5291 dam for the study is due to the lack of periodic analyses by both the operator and the state regulatory agency, its proximity to the urban area, and the presence of road infrastructure on its crest, which represents a significant risk to human life and to the social and economic activities of the municipality. The study of the watershed upstream of the dam allowed for the determination of the inflow hydrograph and the calculation of the region's average annual precipitation. Using RAS Mapper, a tool from the HEC-RAS software, the main channel and the dam structure were defined to simulate the rupture in a non-permanent regime. 132 cross-sections were created along the main channel, spaced 30 meters apart. The methodology of MacDonald & Langridge-Monopolis (1984) was applied to determine the breach failure parameters, resulting in a formation time of 0.21 hours. The simulation in HEC-RAS revealed that the inundation area downstream extends into agricultural areas and that a significant portion of the water does not flow superficially, showing uniformity in the average velocity along the channel. The resulting inundation map showed that the dam rupture would have substantial impacts on the socio economic activities of the population living in Alto Alegre-RR.