Impact of land use and land cover changes on water balance in the Ouémé River basin, West Africa

The influence of land use and land cover (LULC) changes on hydrological processes in data-scarce regions such as the Ouémé River basin is unclear, but it is crucial for sustainable water management and flood mitigation. This study assessed the relationship between LULC changes and changes in water balance using four LULC maps and climate data across three periods within 1998–2016 in the Soil and Water Assessment Tool (SWAT). Model calibration yielded NSE≥0.8 2, RSR≤0.42 and PBIAS≤−12.8, while validation yielded NSE≥0.81, RSR≤0.43 and PBIAS≤−14.4. At the basin scale, expansions in agricultural land and settlements/bare land and loss of savanna and forest areas increased runoff by 66% and reduced baseflow (13%), lateral flow (6%), aquifer recharge (7%) and evapotranspiration (1%). Surface runoff was consistently predicted across periods, making it a key water balance indicator. The findings underscore the need for reforestation, sustainable farming and urban planning to mitigate floods.