Análise de sensibilidade e avaliação da estrutura do modelo BALSEQ em condições distintas de clima, solo e vegetação

Abstract

The evaluation of hydrological models is an essential stage in modeling, but its approach should not be restricted to the use of coefficients comparing measured and simulated data, especially for models where this is not possible, as in the case of groundwater models. Thus, the objective of this study was to evaluate the qualitative aspect of the BALSEQ model. For this purpose, the sensitivity analysis of the input variables was performed, as well as an assessment of the model structure, to detail the behavior of each variable and their interactions with the modeling results. The model offers a simple but quite coherent structure, which allows the user to insert changes and to adapt the model to different climate, vegetation and soil conditions. The results of the sensitivity analysis indicate that the BALSEQ has a different sensitivity for each combination of soil and vegetation modeled, which emphasizes the importance of sensitivity analysis since the model calibration must be done with the most significant variables. In areas with forest cover the most relevant variables for estimating recharge were Canopy Interception (ICV) and the crop coefficient (Kc), which are parameters used to represent the evapotranspiration, while in the pasture and annual crops runoff, represented by the Curve Number method parameter - CN, was the most important variable. In general, CN is the variable with the greatest impact on water balance and therefore should be carefully calibrated.