Does increased hydrochemical model complexity decrease robustness?

► General sensitivity analysis and GLUE were applied to three nitrogen-models of varying hydrological complexity. ► Results highlighted the most complex model as the most appropriate to simulate a small Mediterranean catchment behaviour. ► It is suggested that water quality data help constrain and verify hydrological models correctness. ► Multi-objective criteria led to more reliable models parameters sets. ► The importance of the riparian zone, particularly concerning nitrate dynamic simulation, was pointed out.