INFLUENCE OF THE NATURAL GUTTER ON HYDRAULIC PARAMETERS RESULTING FROM A HYPOTHETICAL DAM RUPTURE

• DOI: https://doi.org/10.22533/at.ed.317472426024

• Palavras-chave: Hydraulic Modeling; Dam Break; HEC-RAS

• Keywords: Hydraulic Modeling; Dam Break; HEC-RAS

• Abstract:

  Resolution number 95 of the National Mining Agency (ANM) requires a Dam Break, being one of the bases of the Emergency Action Plan for Mining Dams (PAEBM), which aims to safeguard the population downstream. Such a study requires models that simulate rupture wave propagation. One commonly used to be HEC-RAS. Among the HEC-RAS input data is the Digital Terrain Model (MDT), which represents the geomorphology of the natural valley. The MDT, obtained from aerial surveys, does not properly characterize the natural bed. For this characterization, topobathymetric sections are used to allow an approximation of this. The study compared two hypothetical simulations of dam failure, one considering the natural valley and the other not. For this purpose, a hypothetical dam, resistance parameters, rupture gap parameters, regional hydrology and representative sections were defined. The results indicated that, for the scenario without a natural bed, there is a greater reduction in hydrographs along the stretch, which can be explained by the resulting higher Manning roughness coefficient. Furthermore, for this scenario, there is a lower propagation speed, translated into a longer arrival time for the same river section, in addition to a greater flood envelope. For the scenario with a natural bed, a higher propagation speed and shorter arrival time were noted, however, a lower flood envelope than the other simulated scenario.