Impacto na produção de sedimentos devido ao uso e ocupação do solo na bacia hidrográfica do ribeirão Piçarrão, Triângulo Mineiro

Abstract

The relationship between man and nature has been the subject of study by many researchers around the world. Particularly noteworthy is erosion, which is a natural process and has increased in magnitude from human interventions in the environment. The objective of this work was to evaluate two scenarios of sediment production due to land use and occupation in the Piçarrão river watershed, Triângulo Mineiro. For this, from a monitoring station near the mouth of the watershed, the hydrological calibration and validation of the total sediments produced were previously performed, with the period from January 2017 to December 2018 for calibration and from January to November 2019 for validation. The Soil and Water Assessment Tool (SWAT) computational model was used for the simulations and the SWAT - Calibration and Uncertainty Programs (SWAT-CUP) in the calibration and validation process. The input data required by the SWAT model were land use map, soil map, terrain slope and climate data. In order to optimize the hydrological and total sediment calibration and validation process, a previous sensitivity analysis in the SWAT-CUP softwae identified the parameters CN2, SOL_K and SURLAG which are, respectively, the number curve, saturated hydraulic conductivity and coefficient of runoff delay as the most sensitive. However, hydrological calibration and validation yielded acceptable results when comparing simulated and monitored surface flow at the watershed mouth, with Nash-Sutcliffe coefficient of 0.63 for calibration and 0.62 for validation. Calibrating the temporal behavior of total sediments yielded a satisfactory result when comparing simulated and monitored total sediments at the mouth of the watershed, with a PBIAS of 52.8, Nash-Sutcliffe coefficient of 0.63. The validation process of the total sediment temporal behavior did not yield acceptable results, with a PBIAS coefficient equal to 55.6. The scenarios analyzed showed that the areas occupied by agriculture are the most susceptible to erosion in the Piçarrão river watershed.RP