Urban pluvial flood risk mapping: a high-resolution assessment for the city of Hamburg

This study develops a high-resolution pluvial flood risk index by integrating hazard modeling, exposure assessment, and social vulnerability analysis following the IPCC risk framework, and applies it to the city of Hamburg, Germany as a case study. The hazard component is based on a 100-year rainfall event (36 mm/h), modeled using a hydrodynamic flood simulation that accounts for topography, drainage capacity, and land use. Exposure differentiates between mobility-related risks and well-being-related risks, while social vulnerability is quantified using socioeconomic indicators such as age, income, and education status. The results highlight risk hotspots where social vulnerability and flood exposure overlap, providing decision-makers with valuable insights for targeted interventions. The study reveals that social vulnerability does not correlate directly with flood hazard, emphasizing the complexity of urban flood risk. This underscores the need for a holistic approach to risk assessment, integrating climate science, infrastructure planning, and social policies to enhance urban resilience. The methodology deployed in this study is useful for other urban areas, showing its value for climate change adaptation planning and risk-informed decision-making.