Abstract:
Water security has been a major challenge in the semi-arid area of West Africa including Northern Ghana, where climate change is projected
to increase if appropriate measures are not taken. This study assessed rainfall and temperature projections and its impact on the water
resources in the Vea catchment using an ensemble mean of four bias-corrected Regional Climate Models and Statistical Downscaling
Model-Decision Centric (SDSM-DC) simulations. The ensemble mean of the bias-corrected climate simulations was used as input to an
already calibrated and validated Soil and Water Assessment Tool (SWAT) model, to assess the impact of climate change on actual evapotranspiration
(ET), surface runoff and water yield, relative to the baseline (1990–2017) period. The results showed that the mean annual
temperature and actual ET would increase by 1.3 °C and 8.3%, respectively, for the period 2020–2049 under the medium CO2 emission
(RCP4.5) scenario, indicating a trend towards a drier climate. The surface runoff and water yield are projected to decrease by 42.7 and
38.7%, respectively. The projected decrease in water yield requires better planning and management of the water resources in the
catchment.
