Flood risk and vulnerability assessment due to dam break
摘要
This study assesses flood vulnerability and risk downstream of the King Talal Dam, located within the Zarqa River Watershed. A comprehensive dataset, including geospatial, hydrological, and socio-economic data, was utilized. The Hershfield method was applied to estimate probable maximum precipitation (PMP), and the resulting probable maximum flood (PMF), with a peak flow of 4300 m3/s, was calculated using the HEC-HMS model with the SCS-CN method. Dam breach parameters were estimated using the Froehlich (2008) model, resulting in breach widths of 82 m and 55 m, and breach development times of 0.82 h and 0.68 h for overtopping and piping failure scenarios, respectively. Dam breach flow was estimated at 45,000 m3/s for overtopping and 29,000 m3/s for piping failure scenarios. Maximum flood depths reached 60 m and 50 m, while maximum flood velocities in Deir Alla were 50 m/s and 23 m/s for overtopping and piping scenarios, respectively. Flood arrival times were as short as 25 min for overtopping and 5 min for piping failure to downstream villages. The Flood Hazard Index (FHI) indicated high flood hazards in Deir Alla for overtopping and medium to high hazards for piping failures. Using the FHI, sensitivity, and adaptive capacity layers, flood risk indices were developed for both scenarios. The results revealed high flood risk for overtopping failure and medium risk for piping failure in the downstream villages. This study highlights the need for targeted flood mitigation strategies, informed by geospatial and modeling analyses, to reduce risk and enhance resilience in vulnerable areas.