Model based distributed water balance monitoring of the White Volta catchment in West Africa through coupled meteorological-hydrological simulations

Sustainable water management requires the quantification of the spatial and temporal changes of water balance variables. Fully distributed hydrological simulations of these variables are especially in regions with weak infrastructure challenging, because the required meteorological input data are often not available in a sufficient spatial and temporal resolution. One possibility to deal with this limitation is to provide the required input data with a meteorological model. This combination results in a one way meteorological-hydrological coupling system. Within the framework of the GLOWA-Volta project it is investigated to what extent meteorological models are able to provide the required meteorological fields with sufficient accuracy for the hydrological modeling. For this study the mesoscale meteorological model MM5 and the fully distributed water balance simulation model WaSiM-ETH were first adapted and validated separately. The research area is the White Volta catchment in the semi-arid to sub-humid climate zone in West Africa. The meteorological simulations tend toward overestimating measured precipitation sums. The coupled meteorological-hydrological runoff simulations show similar model performances as the simulations driven by observations indicating the potential of this system for a contemporary estimation of the terrestrial water balance.