Utilização de modelos digitais de terreno com diferentes resoluções espaciais provenientes de dados Lidar na simulação da ruptura da Barragem em Brumadinho- Minas Gerais

Abstract

The study of hypothetical dam rupture aims to investigate the flood flow through the downstream valley of volume released by partially or total collapsed dam. The objective of this work is to verify the influence of the variation of the scale DTMs as input data, in the results obtained in the hydrodynamic simulation of the rupture of the B1 dam, in Brumadinho, Brazil. Six scenarios of simulation have been defined in such way that the input data and the configuration of the hydrodynamic model remain identical in all of them, except for spatial resolution of MDTs that are different from one to another scenario. According to MDTs, the scenarios of simulation are as follows: C01- 1 m, C05 - 5 m, C10 - 10 m, C15 - 15 m, C20 - 20 m e C25 - 25 m. The MDTs were generated from LiDAR data of the downstream valley. The quality and accuracy of each MDT generated were evaluated through statistical methods in order to relate the quality of the MDT according to the Brazilian standard. From each scenario, the results of the area reached, depth, speed and time of arrival of the flood wave will be extracted, as well as the peak flow values of the rupture wave, accompanied by its time of occurrence. The known information of the actual rupture event will be used as a parameter of comparison with the results of the simulations. The assessment of predicted areas has been done by F index wich account sub and over estimation areas. The results of each scenario were submitted to statistical analysis in order to determine the coefficient of variation (Cv) and thus, verify the discrepancy around the encountered values. Eventually the scenarios presented very similar performance in explaining the rupture of Dam 1. The velocity is the most sensitive variable to terrain alteration, without, however, presenting a very discrepant response compared to the other metrics of this search. Thus, scales greater than 1:10,000 are able to represent an event of magnitude of dam break of B1.