SPATIO-TEMPORAL DYNAMICS OF SOIL EROSION IN SOUTHEASTERN NIGERIA: A GIS AND REMOTE SENSING APPROACH

Soil erosion is among the most severe environmental challenges globally, with its impacts particularly pronounced in southeastern Nigeria where fragile soils, high rainfall, and intensive human activities combine to accelerate land degradation. This study investigated the spatio-temporal dynamics of soil erosion in Orumba North Local Government Area, Anambra State, between 1987 and 2024 using multi-temporal Landsat imagery and Geographic Information Systems (GIS) techniques. Four objectives guided the analysis: to identify anthropogenic drivers of erosion, determine the extent and severity of erosion across land use types, assess its impacts on landscape morphology, and model spatio-temporal changes for sustainable management. The results revealed that anthropogenic pressures farmland expansion, deforestation, sand excavation, and unregulated settlement growth remain the dominant accelerants of erosion, with the Nanka–Oko–Agulu corridor emerging as the most severely affected. Multi-temporal classification showed significant fluctuations in erosion extent: from 7.97 km² in 1987, declining to 2.65 km² in 2003 following reclamation projects, before resurging between 2003 and 2024 as erosion expanded again into farmlands and settlement fringes. Morphological analysis indicated a trajectory of change from attrition (1987–2003), to fragmentation (2003–2019), and dissection (2024), reflecting a progressive decline in ecological stability. Modeling confirmed this degenerative trend, with cycles of short-term stabilization followed by renewed gully expansion under persistent human pressure. The study concludes that sustainable erosion management in Orumba North requires an integrated approach that combines continuous geospatial monitoring, stricter land use regulation, ecological restoration through afforestation, climate-smart farming, and community participation. Without such measures, southeastern Nigeria will continue to experience recurrent cycles of degradation, threatening agricultural productivity, infrastructure, and rural livelihoods.