Water balance responses to land-use/land-cover changes in the Pra River Basin of Ghana, 1986–2025

Abstract

The unfavorable effect of human disturbances in major river basins resulting in extensive variations in the ecosystem has necessitated this research within the Pra River Basin of Ghana. Knowledge about how individual land use influences water balance components will massively improve natural resources planning, management and sustainable development. Land use/cover change in the basin was evaluated by the assessment of six historical and one future land use/cover maps relating to the land use/cover stages in 1986, 2000, 2004, 2008, 2013, 2016 and 2025. The land use/cover maps were deployed to generate seven land use/cover scenarios relating to diverse states of land use/cover change in the basin which were then deployed to simulate the hydrological components. The Soil and Water Assessment Tool was deployed for hydrological simulation. The results revealed that there was a continuous increase in cropland, settlement and mining at the detriment of forest areas from 1986 to 2016, which is expected to continue into 2025. The variations in land use/land cover brought about increment of surface runoff (124.51%) and water yield (40.13%), and reduced baseflow (30.08%) and ET (13.248%). Conversely, the results showed a reduction in surface runoff and water yield during dry season and increased baseflow and evapotranspiration during wet season. These trends are expected to further increase in 2025. Moreover, settlement and mining are the major contributors to changes in water balance components. These results show how important control of land use/cover is in order to maintain water balance components to guarantee water accessibility for all generations.