Impactos do uso da terra na produção de sedimentos em bacia hidrográfica tropical

Abstract

The change of natural landscapes by anthropic activities is the main reason for the deepening of erosion, negatively affecting natural resources and all environments. In this context, it is necessary to know the processes that determine the hydrological balance to avoid erosion. Due to the complexity of a basin and the necessity of making predictions, the development of mathematical models is essential for decision making. When integrated into a Geographic Information System (GIS), these tools can couple the spacetime modeling in a single quantitative structure. Among the existing models, the Soil and Water Assessment Tool (SWAT) can integrate the GIS technics with water balance equations, becoming one of the most utilized models in the world for different purposes. This study aims to evaluate the hydrological response and quantify the soil loss in a basin (Ribeirão do Feijão, in the Brazilian southeast), using the SWAT + model. The simulation was performed by dividing the basin into 31 sub-basins and assigning multiple HRUs (5898). The metrics used to analyze the model's efficiency indicate that the results were satisfactory, Nash-Sutcliffe (NSE) of 0.53 and 0.54 for calibration and validation of streamflow, respectively. The other metrics used represented an excellent response, demonstrating that the observed data and the model simulation correlated well and followed similar patterns. For the production of sediments in the Ribeirão do Feijão Basin, using the current scenario, with an increased presence of vegetation and reforestation, the results indicated a lower production of sediments in most of the channels. Calibration was not performed for sediments due to a lack of monitoring data. The model represented in this study can help guide future planning for land use and occupation of the basin, enabling the forecast of different scenarios and their possible impacts on water production.