“…Calibration is important for both conceptual and physically based hydrological models to provide more accurate runoff estimates, to account for (i) the impossibility of measuring all required model parameters at the model application scale, (ii) lack of process understanding, (iii) possibly overly simplistic process representations, (iv) the spatiotemporal discretization of highly heterogeneous rainfall-runoff processes, and (v) errors in the forcing data (Beven, 1989;Blöschl and Sivapalan, 1995;Duan et al, 2001Duan et al, , 2006McDonnell et al, 2007;Nasonova et al, 2009;Rosero et al, 2011;Minville et al, 2014). Yet, despite the development of numerous calibration techniques over the last 50 years (Dawdy and O'Donnell, 1965;Duan et al, 2004) and the current widespread availability of streamflow observations , macro-scale models generally tend to be uncalibrated (Sooda and Smakhtin, 2015;Bierkens, 2015;Kauffeldt et al, 2016).…”