Xingu River\'s discharge variability over Belo Monte hydropower plant\'s region under scenarios of multimodel climate change projecions

The Belo Monte hydropower plant is located on the Brazilian portion of the Amazon rainforest, in the so-called \"Big Bend\" of the Xingu River. Officially inaugurated in May 2016, the Belo Monte Dam is the largest entirely Brazilian hydroelectric power plant in terms of installed capacity, and the fourth one in the world. However, of the 11.233 MW of installed capacity, the effective generation of energy will be 4.500MW, on average. This happens due to the high seasonality of the Xingu River, whose discharge can change by up to 40 times between dry and wet seasons. Nevertheless, this estimation of the effective energy generation does not consider climate change scenarios projected for the Amazon, which often suggest that eastern Amazon, especially the Xingu River basin, might be considerably drier in the next decades, with drought events happening more frequently and with a higher intensity. In this context, the main goal of this work is to simulate Xingu River\'s future discharge (2020-2050) based on future precipitation projections obtained from five of the Coupled Model Intercomparison Project Phase 5 (CMIP5) climatic models. It also focus on discussing the possible effects of relevant changes in the river\'s discharge over Belo Monte Dam\'s hydropower generation capacity, as well as on the highly significant socio-environmental impacts that already exist. For this purpose, a numeric hydrological model was applied, simulating discharge through runoff calculations derived from the interaction between topography and rainfall. Results point out a decreasing trend in surface water availability, with a 20-30% lower discharge in 2050 when compared to historical data for four out of five models. These results have concerning implications not only on the economic sphere, impacted by Belo Monte\'s future energy generation, which might decline in a similar proportion, but also over socio-environmental aspects, such as an increase in water conflicts and intensification of impacts over aquatic and floodplain ecosystems. In this context, this work also discusses possible socio-environmental consequences and scenarios regarding global changes in climate. (AU)