Globally, floods are the most frequentand damaging natural hazard. This poses a seriousdevelopment challenge to many countries and their efforts toreduce poverty and increase shared prosperity. To helpmanage the impact of floods on people and economies, theWorld Bank provides technical assistance, advisory services,and financial support to a range of countries and citiesaround the world. Facing different types and combinations offlood risk, Japan’s rich history, range of investments andapproaches taken offers a unique knowledge opportunity forother countries seeking to adopt and advance integratedurban flood risk management (IUFRM). This series ofknowledge notes compiles many of the key lessons learnedfrom Japan’s IUFRM efforts. While any strategy to reducedisaster risk must be developed based on a closeunderstanding of local contexts, the aim of this series isto help members of the international community improve theirown approaches to managing urban floods. These notes are notintended to provide a comprehensive analysis but rather asnapshot highlighting key aspects, practice and lessonslearnt from Japanese practice. The four knowledge notes inthis series cover urban floods from assessment and planningthrough to implementation and maintenance.