I'm a PhD candidate researching the human influence on hydrological computer modelling. This mainly entails how different modelling decisions can determine the modelling output. I do this both quantitatively and qualitatively. Quantitatively, I am studying the actual impact different decision, such as calibration period or temporal resolution can have on the model results. This focuses mainly on the scientific hydrological modelling. Qualitatively, I aim to answer the questions: how do practitional modellers make different modelling decisions? And what are possibilities for automation in hydrological modelling? I ask these question during interviews to practitional hydrological modellers in the Netherlands.