Knowledge note 2: Planning and prioritizing urban flood risk management investments

Careful planning and prioritization are critical in the selection of an appropriate mix of integrated urban flood risk management (IUFRM) solutions. An integrated approach to urban flood risk management1 relies on a balance of structural (including nature-based2 ) and nonstructural measures. Building on the results of flood risk assessments, decision makers utilize various tools and methodologies to suit the local context and its specific flood hazards. Some of the criteria considered in the planning and prioritization process include: the probable frequency and strength of floods, potential damage to people and property, cost-benefit analyses (CBAs), social and environmental assessments, and the capacity of existing flood risk management measures. By analyzing the decision-making processes that take place at different governance levels in Japan, this Knowledge Note illustrates how the findings and conclusions of risk assessments are translated into urban flood risk management solutions through the process of planning and prioritizing related investment. Knowledge Note 3 will build on this information and focus on the various aspects to be considered during the design and implementation of IUFRM solutions. In Japan, IUFRM involves collaboration and role sharing among various sectoral departments, those related to rivers, sewerage and drainage, urban development, the environment, and disaster risk management (DRM), and stakeholders. Together with these actors, the public and private sectors, academia, community and civil society organizations, and citizens work together and share responsibilities to achieve the common goal of mitigating and managing urban flood risks in accordance with national laws, policies, plans, and guidelines. Central and local authorities carry out the following steps as part of their various planning and prioritization processes.