Land use change scenarios and their effects on hydropower energy in the Amazon

Accelerated changes in land use in the regions of the Brazilian Amazon and Cerrado in the last four decades have raised questions about the possible consequences for the regional hydrology. Our study area is the Tocantins-Araguaia River Basin (TAW), focusing on the Tucuruí Hydropower Plant (THP), downstream of the TAW. In this study, we evaluated four scenarios of change in land use and cover for the TAW in which forest areas were replaced by pasture, then by agriculture, then by reforestation vegetation and, finally, by regenerated forest to investigate the impacts on the hydrological components of the basin and the hydropower potential of the THP according to these scenarios. For this evaluation, the SWAT model was used to simulate the streamflow of each scenario, so it was possible to predict the hydropower potential in the TAW under different environmental perspectives. Nonparametric statistics were used to identify the efficiency of turbines in converting the streamflow into energy at the 5% significance level. A reduction was observed in the annual evapotranspiration rate and increments were observed in the surface runoff and streamflow, but despite the increase in flow, there was no increase in the energy produced at the THP due to the inability of the turbines to convert excess water into energy, with losses in the energy production of up to 30% per month and 65% in the annual balance. Our results emphasize the importance of the sustainable management of hydrological basins located in tropical regions and aid in planning and decision-making to create public policies that better meet the demand for the exploitation of natural resources.