Modellazione idrologica del bacino del Navigliaccio mediante SWAT+, Pavia, Italia

Hydrological models are essential for understanding watershed dynamics and managing environmental challenges. Watershed is an ideal unit for sustainable water resources management. This study focused on hydrological modeling of the Navigliaccio watershed to understand watershed hydrodynamics, to evaluate the spatial and temporal variability of stream flows in the catchment and to gather actual data about the discharge in the Navigliaccio. The SWAT+ model, which is a physically based, semi distributed hydrological model, designed to forecast the impact of land management strategies on water, sediment, and agricultural chemical yields. SWAT+ model calibrated and validated with monthly evapotranspiration data for the Navigliaccio catchment. Sensitivity analysis conducted in this study showed that the parameters related to soil evaporation compensation factor (ESCO), maximum canopy index (CANMX), plant evaporation compensation factor (EPCO) and soil conductivity were the most parameters in model calibration. The model was calibrated for the period January 2003 to December 2016 and validated for January 2017 to December 2023. The calibration result showed good agreement between observed and simulated evapotranspiration with model performance evaluation statistics NSE of 0.76, KGE of 0.85, and PBIAS of 3.21%. Validation results also indicated good model performance with NSE of 0.73, KGE of 0.81, and PBIAS of 4.79%. Measured hydrological data on Navigliaccio streams were used for ground check of the model, showing order of magnitude agreement with the simulated value. Overall, the SWAT+ model appears to be a reliable tool in simulating the hydrological dynamics of the Navigliaccio watershed. The calibrated model can be used to assess the impact of different land management practices on hydrological responses. Further research could focus on integrating more detailed hydrological data and exploring the effects of various climate change scenarios on the watershed. The model’s application can be extended to other watersheds with similar characteristics to enhance water resource management strategies in catchment level.