Geospatial analysis of land degradation and desertification in the semi-arid Shabelle River Basin, Somalia

Land degradation and desertification pose major environmental challenges in semi-arid regions such as the Shabelle River Basin in Somalia. This study assessed vulnerability to land degradation and desertification from 2000 to 2025 using multi-temporal Landsat images, CHIRPS rainfall data, Google Earth Engine and GIS techniques. A Desertification Vulnerability Index (DVI) was developed by combining nine environmental indicators, including NDVI, SAVI, BSI, SI, NDBI, NDMI, MNDWI, LST and rainfall, using a weighted overlay analysis. Results indicate that large parts of the basin are vulnerable, with the Shabelle River corridor and southern regions comparatively less affected, while other areas show declines in vegetation and environmental health. The DVI shows a temporal trend toward higher vulnerability. It has been effectively used to assess spatial desertification vulnerability and validated with 341 reference points, showing good discrimination for 2000, 2015 and 2025.