Maintaining water availability and electric energy production are the major concerns for the future in countries which are extremely dependent on their water resources like Brazil. The objective of this study was to assess the impacts of climate change on streamflow and therefore on hydropower potential of the Grande river basin headwater region, Southeast Brazil. For this purpose, the SWAT model was used to simulate the hydrological behaviour of the headwaters under the Representative Concentration Pathways 4.5 and 8.5 scenarios, obtained from the Regional Climate Models Eta-HadGEM-ES and Eta-MIROC5 between the years 2007 and 2099. Through power duration curves we estimated the hypothetical average annual energy production at three hydropower plants installed in cascade in the region, being, from upstream to downstream, Camargos, Itutinga and Funil. These plants account for a potential of 277 MW. SWAT was able to simulate the streamflow of the Grande river basin headwaters and, therefore, to reproduce the observed monthly streamflow from the baseline period reasonably well for all three hydropower plants. In general, the results indicated a significant streamflow reduction and therefore reductions in runoff during all the simulated periods and all radiative forcing analysed, when compared to the baseline period. Thus, these results led to reductions in hydropower potential and hence decreases of the annual energy production varying from 6.1 to 58.6% throughout the 21st Century.

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Brazilian Cerrado biome is the largest and richest tropical savanna in the world. In order to understand the effects of climate changes on the hydrology of the Cerrado basins, this paper investigates the hydrological impacts of climate change throughout the 21st century under different emissions scenarios on the streamflow and on the droughts in the Sono, Manuel Alves da Natividade and Palma basins, located in the Brazilian Cerrado. For this purpose, the SWAT hydrological model driven by the downscaling of the HadGEM2‐ES and MIROC5 global climate models associated with RCP4.5 and RCP8.5 scenarios were used in three time slices (2011–2040, 2041–2070 and 2071–2099). The Standardized Precipitation Index (SPI) and the Standardized Streamflow Index (SSFI) were used to characterize droughts. In general, the results showed that the duration, intensity and frequency of the meteorological and hydrological droughts are expected to increase during the future periods. However, the hydrological droughts are projected to be larger than the meteorological droughts. Reductions in the streamflow are indicated in all future time slices and under both RCPs, especially, during dry periods, which may cause negative impacts in the ecological functions of the Cerrado biome, risk for reduction of the recharge of aquifers and risk for the electric energy production in northern Brazil.

Soil erosion is one of the most significant environmental degradation processes. Mapping and assessment of soil erosion vulnerability is an important tool for planning and management of the natural resources. The objective of the present study was to apply the Revised Universal Soil Loss Equation (RUSLE) using GIS tools to the Verde River Basin (VRB), southern Minas Gerais, in order to assess soil erosion vulnerability. A annual rainfall erosivity map was derived from the geographical model adjusted for Southeastern Brazil, calculating an annual value for each pixel. The maps of soil erodibility (K), topographic factor (LS), and use and management of soils (C) were developed from soils and their uses map and the digital elevation model (DEM) developed for the basin. In a GIS environment, the layers of the factors were combined to create the soil erosion vulnerability map according to RUSLE. The results showed that, in general, the soils of the VRB present a very high vulnerability to water erosion, with 58.68% of soil losses classified as "High" and "Extremely High" classes. In the headwater region of VRB, the predominant classes were "Very High" and "Extremely High" where there is predominance of Cambisols associated with extensive pastures. Furthermore, the integration of RUSLE/GIS showed an efficient tool for spatial characterization of soil erosion vulnerability in this important basin of the Minas Gerais state.

This study investigates the applicability of Satellite Precipitation Products (SPPs) in streamflow simulations performed in the Brazilian Cerrado biome, which is one of the world’s biodiversity hotspots. Local data from ground observations were used as a reference for evaluating the Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA) and Integrated Multi-Satellite Retrievals for Global Precipitation Measurement (IMERG). The Soil and Water Assessment Tool (SWAT) was used to simulate the streamflow in a subbasin of the Tocantins river basin. Statistical precision metrics showed that both SPPs presented a satisfactory performance for precipitation monitoring on a monthly scale, in which IMERG performed better than TMPA. The Nash–Sutcliff coefficient and Kling–Gupta efficiency obtained for both calibration and validation period were greater than 0.82 and 0.79, respectively, demonstrating that both SPPs were able to simulate the hydrological regime adequately. However, the bias indicated that the SPPs overestimated the observed streamflow. The r-factor and p-factor values showed that both TMPA and IMERG presented low uncertainty in streamflow simulations. SPPs offer a great alternative for monitoring the precipitation and hydrological studies in the Brazilian Cerrado biome, and presented better simulation results than rain gauges.

Soil erosion is currently one of the main concerns in agriculture, water resources, soil management and natural hazards studies, mainly due to its economic, environmental and human impacts. This concern is accentuated in developing countries where the hydrological monitoring and proper soil surveys are scarce. Therefore, the use of indirect estimates of soil loss by means of empirical equations stands out. In this context, the present study proposed the assessment of the Revised Universal Soil Loss Equation (RUSLE) with the aid of Geographical Information Systems (GIS) and remote sensing for two agricultural watersheds in southern Rio Grande do Sul - Brazil. Among all RUSLE factors, LS showed the closest patterns to the local when compared to the total annual soil loss, thus being a good indicator t of risk areas. The total annual soil loss varied from 0 to more than 100 t ha-1 yr-1, with the vast majority (about 65% of the total area) classified from slight to moderate rates of soil loss. The results estimated according to RUSLE indicated that over 10% of the study area presented very high to extremely high soil loss rates, thus requiring immediate soil conservation practices. The present study stands out as an important scientific and technical support for practitioners and decision-makers, being probably the first of its nature applied to extreme southern Brazil.

HIGHLIGHTS SWAT model effectively estimates the streamfl ow in the Upper Grande River Basin. Deforestation of native vegetation may lead to an increase in runoff and peak fl ow. Reforestation of native vegetation may lead to an increase in infi ltration and soil-water holding capacity.

Soil erosion is one of the most striking environmental degradation processes, which its mapping and assessment is an important tool for management activities and natural resource management in river basins, allowing managers to implement policies and sustainable land use occupation. This work aimed to apply the Revised Universal Soil Loss Equation (RUSLE) in a GIS environment in the upper Iguaçu river basin, located at Paraná State, in order to assess the vulnerability to water erosion as well as the concentration of dissolved solids in suspension to estimate the solid discharge and sediment delivery rate, allowing the identification of more susceptible areas to water erosion. The results showed that over 23.52% of the upper Iguaçu river basin presented soil losses below 2.5 t ha -1 yr -1 , meaning current low potential for erosion. Regarding the solid discharge, the basin has values ranging from low to very high, also leading to high values for sediment delivery rate. The identification of risk areas associated with accelerated erosion, carried out in this study provide important information for measures associated with the management, conservation and planning of land use in the basin, which is highly relevant for predicting development of various scenarios for the state Paraná for its hydroelectric potential.Keywords: Soils; Geoprocessing; RUSLE. RESUMOA erosão do solo é um dos processos de degradação ambiental mais impactantes, no qual seu mapeamento e avaliação consiste em uma importante ferramenta para atividades de manejo e gestão dos recursos naturais em bacias hidrográficas, permitindo aos gestores implementar políticas de uso e ocupação do solo de forma sustentável. O presente trabalho teve por objetivo a aplicação da Equação Universal de Perda de Solo Revisada (RUSLE) em ambiente SIG, na Bacia Hidrográfica do Alto Rio Iguaçu (BHARI), localizada no Estado do Paraná / Brasil, afim de avaliar a vulnerabilidade à erosão hídrica bem como a concentração dos sólidos dissolvidos em suspensão para estimar a descarga solida e a taxa de aporte de sedimentos, permitindo identificar áreas mais suscetíveis à erosão hídrica. Os resultados mostraram que mais de 23,52% da BHARI apresentou perdas de solo abaixo de 2,5 t ha -1 ano -1, significando baixo potencial atual de erosão. Em relação a descarga sólida, a bacia apresentou valores variando de baixo a muito alta, levando também a elevados valores para a taxa de aporte de sedimentos. A identificação de áreas de risco associadas à erosão acelerada, realizadas neste estudo, fornecem subsídios importantes para medidas associadas ao manejo, conservação e planejamento do uso do solo nesta bacia, a qual é altamente relevante para predição de desenvolvimento de cenários variados para o Estado do Paraná por seu potencial hidroelétrico. Palavras