Satellite-Based Assessment of Surface Water Dynamics in the Lake Chad Basin, Borno State Component

The shrinkage of Lake Chad represents one of the most dramatic freshwater loss events globally, with catastrophic consequences for food security, livelihoods, and geopolitical stability across the Lake Chad Basin. This study undertakes a satellite-based assessment of surface water dynamics in the Nigerian component of the Lake Chad Basin, covering the Kukawa and Abadam Local Government Areas of Borno State, using multi-temporal Landsat 5, 7, 8, and Sentinel-2 imagery spanning the period 2000 to 2024. The Modified Normalised Difference Water Index is applied to delineate water body extents for each annual dry-season image acquisition, and time-series water area calculations are performed to quantify decadal and annual variability. Analysis of ENSO, rainfall anomaly, and anthropogenic water diversion records is undertaken to attribute surface water changes. Results indicate a forty-two percent reduction in permanent water surface area in the Nigerian sector between 2000 and 2024, with pronounced interannual variability during below-average rainfall years. Polderisation and recession agriculture encroachment are identified as accelerating the conversion of formerly seasonal lake margins to degraded dryland. The study contributes spatial evidence to the Lake Chad Basin Commission's restoration programme and the Borno State Agricultural Development Programme's irrigation planning efforts. Keywords: Lake Chad, surface water, remote sensing, Borno State, MNDWI.