Flood Vulnerability Assessment of the Juba River Basin in Luuq District, Somalia: A GIS-RS-AHP Approach

Abstract

Flooding remains a major hydro-meteorological hazard for riverine communities in Somalia, yet spatially explicit flood risk assessments remain scarce for the Juba River Basin. This study applies an integrated GIS, Remote Sensing, and Analytical Hierarchy Process (AHP) framework to map flood vulnerability across Luuq District, Gedo Region. Eight conditioning factors (distance from river, elevation, land use/land cover, soil type, drainage density, Topographic Wetness Index, rainfall, and slope) were derived from open-access datasets, including SRTM, Sentinel-2, PERSIANN-CCS, and FAO products. Within the AHP framework, distance from river (30.53%) and elevation (22.81%) received the highest weights, with a Consistency Ratio of 0.047. The resulting Flood Vulnerability Index (FVI) indicates that Moderate vulnerability covers 39.92% of the district, while High (31.01%) and Very High (1.57%) vulnerability zones collectively account for 32.58%, concentrated predominantly along the Juba River floodplain and around Luuq Town. These spatial patterns are supported by ground-level observations and empirical evidence from FAO SWALIM (2023) and UN OCHA (2023), which documented 3,013 ha of flooded cropland (36.9%), 316 damaged buildings, more than 24,000 affected residents, and inundation of Luuq’s main bridge. The findings demonstrate the utility of integrating geospatial modelling with observed flood impacts to identify vulnerable areas and provide a spatial basis for flood-risk reduction and disaster management in data-scarce regions such as Somalia.