Reconstituição da calha natural do reservatório da PCH Salto do Paraopeba

Abstract

The Salto do Paraopeba power plant reservoir is silted since the early 2000s, being the focus of this study to determine its primitive geometry. It is noteworthy, however, that there is no data from the original bathymetry of this reservoir, thus to determine the original geometry sediment transport simulations were performed from calibration by data collected in the field. Simulations were develop with the reservoir in its present condition, but without the restriction imposed by the dam so it was possible to simulate the erosion of the reservoir until the natural flow condition is established. As a premise for defining the primitive geometry morphodynamic equilibrium equations created by Julien were used to help to find the slope of the stretch of the reservoir to be reached in the simulations. Moreover, it was assumed the elevation of the bottom do the dam as threshold for erosion of the reservoir, once reports indicate that the dam was implemented in competent basaltic rock on a steep slope stretch. The results show that after 36 years of simulation the reservoir reached the quota 823.48, corresponding to the original bottom of the dam, indicating that this step is achieved the original reservoir. In order to verify the results found in the simulation of reservoir erosion, silting of thereservoir simulations were performed from primitive geometry found in the simulations of erosion. In these simulations the existing conditions in 1956 were recreated. The results indicate that in 62 years, or 2018, the silting reach similar conditions to that found in 2013 bathymetry. The silted volume is 3.92 Mm³, value 3% lower than that found for the volume for sedimentation occurred between 1956 (year of construction of the power plant) and 2013 (the year when the bathymetry used for the simulations was made).