Análise da sensibilidade e calibração manual dos parâmetros do modelo SWAT para previsão do volume de um açude localizado em uma bacia semiárida.

Abstract

Because it is a very laborious approach, manual calibration of a hydrological model applied to a watershed in a semiarid region requires the modeler to have prior knowledge of the watershed and, if possible, sufficient data to obtain reliable results. Knowing the potential of the SWAT model (Soil and Water Assessment Tool) as a tool for hydrological modeling and considering the lack of studies using this model to predict the volume of reservoirs in watersheds in Brazil, we sought to apply this work. a methodology to perform the sensitivity analysis and manual calibration of SWAT model parameters, aiming to evaluate its effectiveness in the representation of Sumé reservoir volume, analyzing the hydrological processes that take place in the watershed upstream of the reservoir dam. The above-mentioned basin is 770 km2 and is located in the semiarid region of northeastern Brazil. Sensitivity analysis was performed manually on 12 different parameters of the model, using the methodology proposed by Haan (2002), and revealed that only five of them were the most influential in volume prediction, namely: CN2, CANMX, GWQMN, SOL_AWC and ESCO. Manual calibration of the model was performed for the period 1994 and 2008, comparing the modeled volume with the observed one, and taking the Nash-Sutcliffe coefficient (NSE) and the determination coefficient (R2) as indicators of fit quality. At the end, the values of NSE and R2 were greater than 0.5, demonstrating the model's median performance in simulating the volume of the dam under the conditions of the study watershed.