Evaluating a finer resolution global hydrological model's simulation of discharge in four West-African river basins

Performance evaluation of hydrological models enables their consolidation, thereby allowing for the evaluation of water resource conservation approaches. This research aims to evaluate the performance of a finer resolution version (5 arcmin) of the PCRaster Global Water Balance (PCR-GLOBWB) for discharge estimation, in four basins in data-scarce West Africa; the Niger, Komadugu-Yobe, Jama'are, and Ogun. At the Ogun, discharge simulation was validated in a proxy basin, Oueme, which is hydrologically comparable. The model performance was evaluated using Nash-Sutcliffe efficiency (NSE), coefficient of determination (r(2)), Kling-Gupta efficiency (KGE), RMSE-observations standard deviation ratio (RSR), percent bias (PBIAS) and visual plots. PCR-GLOBWB was found to be suitable in all four basins but yielded better performance at three of the basins; the Niger, Jama'are, and Komadugu-Yobe (NSE, KGE, andr(2)above 0.7) compared to the Ogun basin where a proxy validation approach was followed. Results at the Ogun underlined the importance of measured data in hydrological studies. Still, model performance was satisfactory in the Ogun. PCR-GLOBWB performances across the four basins, in the area, validate its reliability as a tool applicable for water resources management strategies and further investigation of impacts of climate variations on river dynamics.