A Proposed Methodological Framework for the Spatial and temporal Calibration of a Large River Basin Hydrological Model

Under a whole system scale analysis, hydrological modelling of large river basins is critical to understand the behaviour of regional phenomena and cumulative impacts. Many hydrologic models contain parameters that are difficult to measure or do not have a direct physical interpretation, so it is necessary to estimate these model parameters using a calibration procedure. However, observations for calibration and validation are only available for specific locations and more formal procedures are necessary to regionalize model parameters in areas with limited or without data. In this paper, a methodological framework for the spatial and temporal calibration of a large river basin hydrological model is proposed that uses a cluster method to group sub-catchments of the macro basin model, based on its morphometric characteristics, under the assumption that catchments in the same group share the same parameter values in the model. The methodology was tested in a Magdalena-Cauca (Colombia) macro basin hydrological model developed in the Water Evaluation and Planning (WEAP) software (Stockholm Environmental Institute, Stockholm, Sweden). The results show a Nash-Sutcliffe efficiency coefficient between 0.45 and 0.83 in calibration and between 0.43 and 0.83 in validation.