Using Field Measured Parameters with the SWAT Hydrological Model to Quantify Runoff at the Sub-watershed Level

The SWAT hydrological model is a semi-distributed physically based model. As a physically based model, parameters are measurable in the field and can be implemented in the model. This study aims to evaluate the potential of integrating field data ( hydraulic conductivity, bulk density, and canopy storage) into SWAT, and investigates its benefits for a Canadian watershed. SWAT can run based on the empirically based Curve Number (CN) or the physically based Green and Ampt (GA) runoff method, both of which are evaluated with and without field data. Without calibration or validation, adding field data improved performance of the GA method for both the calibration and validation years, but the CN method only improved for the validation year. The CN calibrated or validated model did not benefit from field data, but the GA model significantly improved for the calibrated years and showed no improvement for the validated period.