The authors aim providing a model evaluation framework for complex hydrological schemes, comprising a large number of unknown parameters. Taking as example the SWAT model, applied to two river basins in southern Minnesota, USA, they highlight several interesting issues, involving the choice, estimation and classification of parameters and the use of appropriate evaluation metrics, which are contrasted to single-objective calibration practices. In this context, they propose a three-stage procedure for parameter classification, and a more comprehensive model assessment framework, implemented within the so-called HydroME Toolbox. The latter comprises several graphical tools for the visual comparison of simulated vs. observed outputs both C1