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.

Indicators of hydrological sustainability, governance and water resource regulation in the Moju river basin (PA) - Eastern Amazonia.

Water is one of the natural resources most impacted by the development model adopted in Brazil. This is related to the widespread sense that water is abundant in the country, which makes it difficult to fully engage all levels of government. However, this sense of abundance also obscures the real problems of pollution, demand, availability and water resources conflicts. This study aims to strengthen water management and contribute to the evaluation of the processes of development in the northeast region of the state of Pará. This study uses Hydrographic Basin Sustainability Indices to consider the hydrological, environmental, social and water resources management situation of the Moju River Basin and to suggest a payment model for the use of its water resources. The results indicate that the existing framework of water use regulation is characterized by moderate sustainability and governance scores and a low degree of collection of fees for the use of water. In general, with the increase in the number of enterprises authorized to withdraw water from and release effluents into the river, there is a lack of information about water demand and availability. The water governance framework is characterized by poorly integrated environmental and water management common to most Amazonian municipalities. Thus, the Moju River Basin represents a pattern of unsatisfactory water resources management. This pattern highlights the importance of implementing existing water resources and environmental policies to reduce conflicts that involve land and water use.