Groundwater recharge and geospatial heterogeneity by hydrological modelling under climatic influence: the case of the Davo River watershed (south-east of Côte d'Ivoire)

The sustainable management of groundwater resources in Côte d'Ivoire requires a reliable estimate of groundwater recharge. This study proposes a methodology for assessing the recharge of the Davo watershed (South-West Côte d'Ivoire) through distributed hydrological modelling with the HYDROTEL software. Physiographic (DEM, soils, land cover) and hydrometeorological (rainfall, discharge, evapotranspiration) data were integrated into the model via PHYSITEL. The three-layer vertical water budget (BV3C) was used to estimate vertical flows and potential aquifer recharge. The results indicate an average annual recharge of 221 mm, with spatial variability between –27 and 644 mm/year depending on the hydrological units. The performance of the model is considered satisfactory (Nash-Sutcliffe = 0.62), volume deviation = -1.11%). The sensitivity analysis shows the major role of evapotranspiration and land use on recharge, confirming the impact of deforestation and enthronization on the reduction of infiltration. This integrated approach provides a robust scientific basis for the quantitative assessment of groundwater resources and can be replicated in other similar contexts when all the required conditions are met.