Rapid flood risk assessment and adaptation planning for climate resilient developments: a Rio de Janeiro case study

Climate resilient development must be risk-informed to protect citizens, homes, and infrastructure from climate risks. Especially, urban floods underscore the vulnerability of cities and the complex challenges in managing growth and development. 

Here we present two tools to support flood risk assessment and adaptation planning.  HydroFlows  (developed in the UP2030-HE project) provides modular workflows for standardized and reproducible probabilistic flood risk modelling and assessments based on a cascade of climate, hydrological, hydrodynamic and socio-economic impact models. The tool generates flood hazard and risk maps for various climate and urbanization scenarios. First, a rapid first-order flood risk screening can be performed based on global datasets at any given location, which can be refined further with local data where available. FloodAdapt leverages HydroFlows-generated data to bring the power of flood and impact modelling to a wider group of practitioners, such as policymakers and city staff, enabling them to explore different mitigation and adaptation strategies hands-on through a user-friendly graphical interface. This tool supports the economic and social evaluation of measures such as floodwalls, urban greening, water storage, elevating homes, buyouts, and floodproofing under diverse flood events and future conditions. 

The Acari River basin in Rio de Janeiro, a densely populated and flood-prone region, has experienced significant floods, including a major event in January 2024 affecting 78,000 people. These floods caused extensive damage to homes, infrastructure, and public services. Despite ongoing efforts to improve drainage and build protective infrastructure, rapid urbanization and climate-related heavy rains continue to pose challenges. While the city has high-quality data, there is a need for comprehensive flood models to assess and predict flood risks. By combining these local datasets with public global data and our tooling, we were able to analyse how our tools can contribute to more informed, effective flood risk management and support climate resilient development.