Modelagem hidrossedimentológica na Bacia Hidrográfica do Rio das Mortes, UPGRH-GD02

Abstract

Human actions are responsible for considerable changes in the basin environment, in view of its quantitative and qualitative influence on the hydrological processes. In this context, hydrologic modeling is a useful tool to predict the dynamic behavior of water in a basin and, therefore, provides a detailed estimate of water balance, this information is a great value for management of water resources. The objectives of this work include: (i) approach different calibration strategies and SWAT model testing of hydrologic simulation in the basin of the Rio das Mortes - MG, by evaluating 6 fluviometric stations with drainage area between 272 and 6070 km 2 ; (ii) evaluate the applicability of SWAT model as a tool for the management of water resources through it’s hydrologic and sedimentological simulation; (iii) estimate the sediment yield spatially distributed by sub-basins and identify the areas with greater contribution of sediments in the basin; (iv) evaluate the sediment load export into the Funil reservoir between (2002) to (2015). The statistics used to evaluate the quality of the calibration and validation where the Nash and Sutcliffe (CNS) and the percent bias (PBIAS). More completely the statistics used, in calibration and validation made used the optimization algorithm “Sequential Uncertainty Fitting version 2” (SUFI-2) which provided an uncertainty analysis through graphical analysis of the bands of 95% uncertainty of prediction (95PPU), accompanied by indexes P-factor and R-factor. The obtained results of statistical indices applied in the model performance analysis, qualified SWAT to be appropriate in the simulation of daily and monthly streamflow and monthly sediment yield in the basin of the Rio das Mortes. The SWAT model was sensitive to the size of the drainage area, showing good results when combining larger drainage area stations in the calibration process. The adopted strategies confirmed the applicability of the model as a management and planning tool of water resources for smaller basins without data. The HRU having pasture, with Argisol, Neosol, Cambisol, and undulated relief were the main areas with greater sediment contributions. These results are important in identifying the high priority areas for soil and water conservation measures. It was estimated that Mortes River Basin delivered to the Funil Hydropower Plant reservoir in 14 years the total of sediment load equaled 6,682,704 m 3 (16,706,761 ton), this value corresponded to 2.6% of storage capacity. Finally, the results obtained in this study provide useful information for water resource planning and management in the Mortes River Basin region, enabling the rational use of water in the basin.