Efficient flow calibration method for accurate estimation of baseflow using a watershed scale hydrological model (SWAT)

Accurate analysis of water flow (streamflow and baseflow) is important for accurate water resources management. For accurate water resources management, modeled surface and groundwater hydrology should be calibrated simultaneously. The objectives of this study are: 1) to develop and provide an efficient flow calibration method (EFCM) for accurate baseflow estimation by combining the Sequential Uncertainty Fitting algorithm version 2 (SUFI-2) and modified SWAT 2012 code and 2) to evaluate the performance of the EFCM for streamflow and baseflow estimation. Both streamflow and baseflow estimated using the EFCM performed well based on three model evaluation methods (i.e., NSE, R-2, and PBIAS). Thus, the EFCM would be a practical method for accurate water resources management by calibrating baseflow accurately as well as streamflow at a watershed scale. This study can be used as a data-driven model groundwater modeling because the baseflow-related parameters (i.e., groundwater recharge and hydraulic conductivity) calibrated in this study can be used as a set of input data (initial parameter values) in computer-based numerical groundwater models.