PREDICTION OF WATER YIELD AND BALANCE IN UPPER OUEME RIVER CATCHMENT IN BENIN REPUBLIC

Abstract

In a river catchment, prediction of water yield and water balance is an important requirement for sustainable water resources management. This study aimed at predicting water yield and water balance of Upper Ouémé catchment in Benin Republic using SWAT model. Meteorological and hydrological data required were obtained for a period of 20-years while the required spatial data were retrieved from various archives. The statistical measures such as Nash-Sutcliffe Efficiency (NSE), Percent Bias (PBIAS), and Coefficient of determination (R2) were used to evaluate the model performance. The outcome shows that evapotranspiration has the highest share of about 31% of the water balance while lateral flow has the lowest share of about 1% of the water balance. The model estimated total yield of the basin as 1,867,161 mm of water between the simulation periods of 1998-2017 with sub-basin 90 having the highest contribution of 837.87 mm and sub-basin 100 with lowest contribution to water yield. The observed flow was compared with simulated flow using SWAT. Both calibration and validation statistics were greater than 0.6 as indicated by NSE and R2 which shows that there was a good agreement between the observed and simulated flows. The study would help in sustainable management of water resources.