A flood vulnerability index and decision tree framework for building resilience in Sudan

Sudan experiences recurrent floods that cause widespread damage to housing and infrastructure, particularly in settlements where construction practices and environmental conditions increase exposure to floodwater. This study presents an integrated framework for assessing and managing building vulnerability through the combined use of a Flood Vulnerability Index (FVI) and a Decision Tree Analysis (DTA). The FVI quantifies structural and environmental vulnerability using indicators derived from field observations and documented flood events across six affected regions in Sudan, including Khartoum (Sharg Elneile), Wad Ramli, Al Managil, Northern State, Tokar, and the Arbaat Dam area. Building vulnerability was evaluated through materials, foundation type, and elevation, while environmental vulnerability accounted for proximity to water bodies, drainage performance, climate variability, and historical flooding. The DTA translates these quantified results into tailored mitigation and adaptation pathways aligned with the severity of risk. Findings show that high vulnerability levels are consistently associated with combinations of weak construction materials (e.g., adobe and lightweight roofing), inadequate or absent foundations, poor drainage conditions, and close proximity to flood-prone water channels. The hybrid FVI–DTA framework provides a clear and practical process for prioritising interventions, guiding reconstruction, and improving preparedness in flood-prone areas.