Estudo de ruptura da barragem de funil: comparação entre os modelos FLDWAV e HEC-RAS

Abstract

The damage caused by events of rupture of large dams have, in general, catastrophic consequences, especially when these are located upstream of urbanized regions. The development of EAP - Emergence Action Plans have the purpose of evacuation of the population installed downstream and minimization of losses associated in the case of occurrence of the dam break located upstream. A EAP must contain the maps of flood-prone areas, that their execution is based in the prediction and calculation of maximum flooded elevation, speeds and maximum discharges, obtained with the use of models for the propagation of waves of a flood along the valley downstream, caused the rupture of dams. A great advance in the process is the use of GIS - Geographic Information Systems. However, there are still several sources of uncertainties in obtaining robust flood-prone area maps mainly due to difficulties in the determination of the breach type and the related flood hydrogram, in the estimation of correct hydraulic parameters, in the availability of an adequate number of cross-section profiles obtained in the field, in the availability of cartographic maps with adequate scales and in the limitation of the flood routing mathematical models. It is common the use of Saint-Venant equations to carry out the routing of dam break flood waves, as it is the case of the FLDWAV and HEC-RAS models. In this research, financed by FINEP, the outputs of those models are compared considering the hypothetical rupture of the Funil Dam, located at the ParaÌba do Sul river, in the Rio de Janeiro state. In addition, the results of hydrodynamic models are used for the mapping of the flood-prone areas, where was used the software ArcView GIS 9.3. In both models and scenarios simulated, it was found that the flow of rupture is extremely reduced to the cross-section located 42,4 km from the axis of UHE Funil, and then the propagation of flow is little significant. The times of arrival of the wave peak of rupture is less than 5 hours in the first cross-sections, by Resende, and about 35 hours at the end of the river modeled, in TrÍs Rios. The maximum flood depths obtained in the models vary widely among the scenarios for the initial stretch, however,for the final stretch of the variation isn't significant.