Hydrograph separation for tackling equifinality in conceptual hydrological models

Attributing a physical meaning to the calibration of conceptual hydrological model is risk due equifinality, i.e., existence multiple optimal parameterizations that might or not represent actual behavior catchment; propagates posterior studies use outputs as an input. This study proposes and analyses sequential procedures for calibrating models aimed at reducing equifinality. These force reproduce flow separation observed streamflow into quick base flow, which we assumed representative run-off generating processes in catchment. The parameters control forces separation, introduces additional constraints process reduce equifinality improve overall procedure. We applied this procedure two mesoscale catchments “Picos de Europa” National Park (northern Spain). compared performance different both real scenario hypothetical scenarios land soil permeability, provide sounder assessment ability under diverse conditions. Results show method applying hydrograph ensures with better discharge partition, whereas methods do apply failed considerable number cases. In terms (NSE bias), outperformed reference (without separation) scenario, even total streamflow; though, improvement representativeness came expense slight loss performance. here developed were more computationally efficient; since they explore parameter space subsets, iterations until convergence was third needed method. summary, have simple (more line underlying conceptualization) similar, better, shorter time than