Distributed hydrological modelling of the Senegal River Basin — model construction and validation

A modified version of the physically-based distributed mike she model code was applied to the 375,000 km2 Senegal River Basin. On the basis of conventional data from meteorological stations and readily accessible databases on topography, soil types, vegetation type, etc. three models with different levels of calibration were constructed and rigorous validation tests conducted. Calibration against one station and internal validation against eight additional stations revealed significant shortcomings for some of the upstream tributaries, particularly in the semi-arid zone of the river basin. Further calibration against additional discharge stations improved the performance levels of the validation for the different subcatchments. Although there may be good reasons to believe that the model operating on a model grid of 4×4 km2 to a large extent reflects field conditions at a scale smaller than subcatchment scale, this could not be validated due to lack of spatial data.