Comprehensive flood vulnerability analysis and mapping for the Awash River Basin, Ethiopia

Abstract

The Awash River Basin is increasingly susceptible to significant flood risks driven by a complex interplay of hydrometeorological and socio-environmental factors, which have detrimental effects on local populations and infrastructure. Despite some advancements in flood risk assessment, existing mapping methodologies, including ArcGIS and HEC-RAS, often fail to account for critical dynamics within the river system, leading to gaps in flood hazard assessments that overlook vital regions and create discrepancies in estimates of vulnerable populations during recent flooding events. This study employs comprehensive mapping techniques, utilizing global datasets, HEC-RAS, GIS, and satellite data to characterize various flooding types throughout the basin. Among the methodologies analyzed, the Fathom and Aqueduct models demonstrated superior accuracy in estimating flood impacts, while the CAMA-UNEP and JRC models revealed significant limitations, especially in capturing flood risks in the upper reaches of the basin. By enhancing real-time monitoring and vulnerability assessments, this research aims to improve resource allocation and intervention strategies, ultimately safeguarding at-risk communities and mitigating socio-economic repercussions from flooding events in the Awash River Basin. The findings support the recommendation of the Fathom and ensemble models for conservative flood mapping, while the Aqueduct model is recognized as a valuable alternative for accurate estimations.