Modeling the impact of land cover changes on water balance in the Vea catchment of Ghana, 1985–2040

The ensuing effect of global land use changes on watershed hydrology is enormous, particularly in rapidly developing countries such as Ghana. Understanding how watershed land use dynamics influence hydrology is essential to devising effective land and water resources management strategies. This study evaluated the impact of land-use changes on hydrological components in the Vea catchment of Ghana from 1986 to 2040 using the Cellular Automata (CA)-Markov chain model for land change modeling and Soil Water Assessment Tool (SWAT) for hydrological modeling. The models performed satisfactorily with NSE values of 0.74 and 0.78 for calibration and validation, respectively, in SWAT and an overall Kappa value of 0.89 in CA-Markov. The land cover change analysis revealed a continuous increase in farmland and built-up areas alongside decreasing savanah forest which resulted in increased Curved Numbers (CN) from 81 in 1986 to 86 in 2040. Consequently, ET and baseflow decreased by − 7.8% and − 26.2%, respectively, while surface runoff, and water yield increased by 46.9%, and 5.1%, respectively. Despite the general decline in baseflow, the seasonal trend showed an extention to January, indicating adequate storage of water in the shallow aquifer that can be extracted for dry season gardening. While vegetation restoration is critical to reducing eroded sediment yield to guarantee reservoir storage, constructing dams and dugouts to harness the high surface runoff for irrigation and livestock watering in the long dry season is also needful.