Testing the value of globally available data for detailed hydrological modelling : Case study of Aa of Weerijs catchment, the Netherlands

Distributed hydrological models are preferred in hydrological modelling because of their ability to present spatial variability of data and parameters. Their use, however, requires a large number of data which are often not available. While effort has been made to make different data sets available, the applicability of driving distributed hydrological models of small catchments with globally available data sets is still largely unknown. This research strived to explore and assess the usefulness of these globally available data in detailed hydrological modelling of relatively small catchments using the MIKE SHE modelling software and the Aa of Weerijs catchment as the study area. An initial hydrological model of the catchment was developed first to study the catchment’s hydrology and later to be used to test different global data sets inputs. This model was set up using readily available local data combined with global data sets of topography, land use and soil type. Simulated discharge at the catchment outlet and groundwater head at several locations were compared to observations. Results indicated that the discharge is characterized by considerably high peaks in wet winter periods and very low flows in summer periods. Drain flow from the saturated zone and surface runoff are the main contributors to river flow. Groundwater head changes significantly across the catchment and local drainage conditions mainly influence its variation. Furthermore, three globally available climate data sets were tested; the ERA5-Land total precipitation and total evaporation from the COPERNICUS Climate Data Store, and the IMERG-final run precipitation from NASA’s Goddard Earth Sciences Data and Information Services Center (GES DISC). The obtained results indicate that when precipitation data sets were used a larger difference between the model’s results and the results obtained by using local data was observed. The ERA5-Land total evaporation data set on the other hand did not show significant disparities with local data results. Despite the appearing discrepancies, the tested data sets were able to reproduce the simulated discharge pattern using local climate data quite well. Therefore, the findings indicated that the tested data sets can be used as potential secondary data sets