Uso do QSWAT+ para modelagem hidrológica na microbacia do arroio Cambaí em Itaqui, RS

Abstract

The watershed of the Cambaí stream is characterized by rice-growing activity, having a dense drainage network that includes dams for storing water for irrigation, as well as numerous channels, both natural and artificial, with the mouth in the Uruguay River. The dynamics of the hydrologic cycle in the basin is affected mainly by the precipitation regime, land use, and the characteristics of the relief along its drainage network. The SWAT+ model, acronym in English of the Soil and Water Management Tool, was developed by the United States Department of Agriculture to model agricultural basins, and allows, after the calibration process, the prediction of flow rates at different points in the basin, as well as the sediment and nutrient loads or pesticides that can be expected. The proposal developed in this work was to use the QSWAT+ extension of the well-known geographic information system software QGIS for the initial study of the basin aiming at the future application of the SWAT model in its entirety. To this end, satellite images, SRTM sensor, pedological and land use and occupation data were used. The processing prepared in QSWAT+, this being the initial part of the SWAT model, allows the characterization of hydrological response units, which are the basis of the model's application. To simulate the water levels within the basin, the same equations from the SWAT model were used, but using them within the mathematical software Scilab, thus obtaining the expected water levels after precipitation in the Cambaí stream. The different stages of the process are useful for the future application of the SWAT model and are explained in detail in this work.