ABSTRACT Land-use changes promote significant variations in streamflow regimes, and hydrological models allow studying their impacts. Based on this approach, this study aimed to assess the applicability of the SWAT model for different land-use scenarios and their respective impacts on the flow regime of the Mucuri River. The average monthly and daily water balance was generated after the calibration and validation of the SWAT model in the basin. Three land-use scenarios were analyzed in relation to the current land use, as follows: replacement of the agricultural area by the eucalyptus crop, replacement of the native forest area by the sugarcane crop, and replacement of pasture by exposed soil. The results showed that the SWAT model is adequate to simulate the land-use change and its impact on the flow regime of the Mucuri River; the replacement of agriculture by eucalyptus in the basin led to a decrease in the average and minimum reference streamflows; and the replacement of the forest cover by sugarcane and pasture by exposed soil provided an increase in the average and minimum reference streamflows.

ABSTRACT Hydrological models are becoming more and more widespread, mainly due to their capacity to simulate the impact of environmental changes on water resources. In this way, the aim of this study was to calibrate and validate the SWAT model for the soil and climatic conditions of the Mucuri River Basin, located in the Northeast region of the States of Minas Gerais, Brazil. The SWAT-CUP software module SUFI2 was used to analyze the sensitivity, calibration and validation of the model. The calibration was performed in an intermediate fluviometric station and the validation in five other located: three upstream, one downstream and one independent from the calibration point. It was evidenced for the study area that the parameters referring to the basic flow processes were more sensitive. The model obtained a good adjustment with an overestimate tendency of 15%. In general, the SWAT model, using SWAT-CUP was good and adequate in terms of its calibration performance and validation of the flow simulation in the Mucuri River Basin by the determination coefficients, Nash-Suttclife efficiency and percentage of trend.

Devido à carência de informações relativas às equações de precipitação máxima para a maioria das localidades do Estado de Mato Grosso do Sul, a alternativa para a realização de projetos de obras hidráulicas tem sido utilizar informações de postos meteorológicos mais próximos da localidade na qual o projeto é realizado ou fazer uso de metodologias alternativas, tal como o método de desagregação de chuvas de 24 horas, a partir de dados pluviométricos em função da maior disponibilidade de estações e maior tempo de observações. Com base nesse enfoque, o objetivo do trabalho foi estimar as equações de precipitação máxima para o Estado de Mato Grosso do Sul por meio do ajuste da metodologia de desagregação de chuvas de 24 horas, em função dos dados obtidos das estações pluviográficas de Dourados e de Campo Grande. Para tanto, foram utilizados dados consistidos em 105 estações pluviométricos, disponíveis no banco de dados da ANA. Com base nos resultados, foi possível concluir: as equações de chuvas intensas obtidas pela análise de pluviogramas apresentaram coeficiente de determinação acima de 99%; e o desempenho do ajuste da metodologia de desagregação de chuvas de 24 horas foi classificado como ótimo, com base no erro médio relativo ao índice de concordância de WILMOTT (1982).

Due to the lack of information concerning maximum rainfall equations for most locations in Mato Grosso do Sul State, the alternative for carrying out hydraulic work projects has been information from meteorological stations closest to the location in which the project is carried out. Alternative methods, such as 24 hours rain disaggregation method from rainfall data due to greater availability of stations and longer observations can work. Based on this approach, the objective of this study was to estimate maximum rainfall equations for Mato Grosso do Sul State by adjusting the 24 hours rain disaggregation method, depending on data obtained from rain gauge stations from Dourado and Campo Grande. For this purpose, data consisting of 105 rainfall stations were used, which are available in the ANA (Water Resources Management National Agency) database. Based on the results we concluded: the intense rainfall equations obtained by pluviogram analysis showed determination coefficient above 99%; and the performance of 24 hours rain disaggregation method was classified as excellent, based on relative average error WILMOTT concordance index (1982).