“…Examples of toy experiments from the probabilistic hydrological modelling literature are available in Krzysztofowicz (1999), Beven and Freer (2001), Stedinger et al (2008), Farmer and Vogel (2016), and Volpi et al (2017). Toy models have also been exploited for other modelling situations in geoscience (see e.g., Koutsoyiannis 2006Koutsoyiannis , 2010; see also the references in Koutsoyiannis 2006), while falling into the broader category of simulation or synthetic experiments, which are increasingly conducted within various hydrological contexts, including some more relevant to the present study (see e.g., Kavetski et al 2002;Vrugt et al 2005;Montanari 2005;Montanari and Koutsoyiannis 2012;Montanari and Di Baldassarre 2013;Papacharalampous et al 2018Papacharalampous et al , 2019aRenard et al 2010;Sadegh and Vrugt 2014;Sadegh et al 2015;Sikorska et al 2015;Schoups and Vrugt 2010;Tyralis and Papacharalampous 2017;Tyralis et al 2013;Vrugt et al 2003;Vrugt and Robinson 2007;Vrugt et al 2008;Vrugt et al 2013;Vrugt et al 2016); see also Montanari (2007) for a discussion on the significance of this type of experiments. In fact, simplified modelling situations can be useful as starting points for achieving effective real-world modelling, especially in cases where analytical solutions exist (see e.g., Volpi 2012).…”