Print Email Facebook Twitter A rainfall threshold-based approach to early warnings in urban data-scarce regions Title A rainfall threshold-based approach to early warnings in urban data-scarce regions: A case study of pluvial flooding in Alexandria, Egypt Author Young, A.T. (TU Delft Hydraulic Structures and Flood Risk; UNESCO-IHE) Bhattacharya, Biswa (UNESCO-IHE) Zevenbergen, C. (TU Delft Hydraulic Structures and Flood Risk; UNESCO-IHE) Date 2021 Abstract Rapidly expanding cities in the Middle Eastern and North African (MENA) region are at risk of flooding due to heavy rainfall, insufficient drainage capacity, a lack of preparedness and insufficient data to conduct required studies. A low regret Early Warning Systems (EWS) using rainfall thresholds is proposed as a cost-effective short-term solution. This study aims to utilise a probabilistic approach to characterise and predict urban floods by assessing critical rainfall thresholds likely to cause flooding combined with ensemble precipitation forecast in Alexandria, Egypt. Rainfall thresholds were inferred by associating observed rainfall and historical flood information sourced from social media and newspapers. Floods were classified in a colour-coded hazard matrix as no flood (green), minor flood (yellow), significant flood (orange), and severe flood (red). Probability of occurrence of hazard classes was derived by incorporating ensemble rainfall into the hazard matrix to jointly evaluate likelihood and hazard severity. Results from this study showed that three of four severe events analysed could have been predicted with a high likelihood up to 24 hr before. The presented approach supports decision making to issue warnings and flood control actions with limited data and is a model for other data scare regions. Subject early warning systemsEgyptpluvial flood forecastingrainfall thresholds To reference this document use: http://resolver.tudelft.nl/uuid:c1b952c5-066c-4c0f-bf14-88784de2ad50 DOI https://doi.org/10.1111/jfr3.12702 ISSN 1753-318X Source Journal of Flood Risk Management, 14 (2), 1-16 Part of collection Institutional Repository Document type journal article Rights © 2021 A.T. Young, Biswa Bhattacharya, C. Zevenbergen Files PDF jfr3.12702_1_.pdf 2.91 MB Close viewer /islandora/object/uuid:c1b952c5-066c-4c0f-bf14-88784de2ad50/datastream/OBJ/view