Integrating InSAR and GIS for Assessment of Land Subsidence in the Niger Delta

The Niger Delta's low-lying coastal plain is subject to natural sediment compaction, groundwater extraction, and oil production-induced subsidence, making it critically vulnerable to sea level rise. This study integrates Interferometric Synthetic Aperture Radar techniques and GIS to produce high-resolution land subsidence maps across the western Niger Delta in Delta State. Sentinel-1 SAR image stacks spanning 2019 to 2024 are processed using the Small Baseline Subset algorithm to derive surface deformation velocity fields at millimetre precision. Subsidence rates are spatially analysed in relation to geological units, groundwater well density from state water board data, and petroleum production zones. Results reveal maximum subsidence velocities exceeding 18 millimetres per year in the Effurun-Warri industrial corridor and 11 millimetres per year in coastal communities of Burutu LGA. A multivariate spatial regression model explains 69 percent of the variance in subsidence rates through a combination of geological and anthropogenic predictor variables. The study provides evidence for the Delta State Government and the Federal Ministry of Environment in formulating coastal adaptation policies for subsidence risk reduction. Keywords: land subsidence, InSAR, Niger Delta, Sentinel-1, groundwater