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Resumo -Este trabalho objetivou estimar e mapear a erosividade média (EI 30 ) mensal e anual, analisar a distribuição espacial da precipitação, durante o período chuvoso, e identificar zonas similares quanto a EI 30 : erosividade média-alta, nas regiões central, nordeste e parte da Zona da Mata; alta, no Triângulo Mineiro (extremo da região), e parte do nordeste e sul do Estado; e muito alta, na maior parte do Triângulo Mineiro, Alto Paranaíba, noroeste e leste. A erosividade não apresentou relação com a latitude e longitude e foi influenciada por efeitos orográficos e características climáticas de cada região.Termos para indexação: erosão hídrica, mapeamento, geoestatística, EI 30 . Monthly and annual rainfall erosivity for Minas Gerais StateAbstract -This work aimed to map monthly and annual rainfall erosivity (EI 30 ) mean, to analyze rainfall erosivity distribution, during rainfall season, and to identify rainfall erosivity zones in Minas Gerais State, Brazil. Daily pluviometric data from 248 weather stations dispersed in the State were used to determine the Fournier´s rainfall coefficient (Rc). Based on the relation EI 30 x Rc obtained for some locations, EI 30 was calculated for each weather station. Geostatistical tools were applied to map EI 30 and pluviometric data. Minas Gerais comprises three zones with annual rainfall erosivity varying from 5,000 to 12,000 MJ mm ha : medium-high erosivity, for central, northeastern and part of Zona da Mata; high, for Triângulo Mineiro (extreme of the region), and part of northeast and south of State; and very high, for most part of Triângulo Mineiro, Alto Paranaíba, northwest and east of State. Rainfall erosion behavior has not presented relation with latitude and longitude, and was influenced by orographic effect and weather characteristics of each region.

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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