Spatial Analysis of Land Use Change and Its Effect on Groundwater Recharge in Ogun State

Urbanisation and agricultural intensification alter the land surface properties that govern groundwater recharge dynamics, with implications for water supply sustainability. This study analyses land use change and its effect on groundwater recharge potential in Ogun State using remote sensing, GIS, and hydrological modelling. Land use and land cover maps for 2010, 2016, and 2022 are produced from Landsat imagery using Random Forest classification. Impervious surface fraction, NDVI, and soil type maps are used as inputs to the Natural Resources Conservation Service Curve Number model to estimate direct runoff and potential groundwater recharge for each land use scenario. Results indicate that impervious surface increase of 38 percent between 2010 and 2022 in Sagamu and Ijebu-Ode urban areas has reduced potential recharge by approximately 24 percent, threatening the long-term sustainability of hand-dug wells and shallow boreholes relied upon by peri-urban communities. Spatial recharge potential maps identify remaining natural land surfaces critical for groundwater replenishment. Keywords: land use change, groundwater recharge, Ogun State, remote sensing, impervious surface