Flood risk management approaches: As being practiced in Japan, Netherlands, United Kingdom and United States

Many countries are reassessing their approaches in the face of improved understanding of flood risks. The Japanese Ministry of Land, Infrastructure, Transport and Tourism (MLIT), the Dutch Rijkswaterstaat, the United Kingdom Environment Agency, and the United States Army Corps of Engineers agreed in 2009 to develop a document to explore risk-informed approaches as being practiced and developed primarily in those four countries. Although very different in frequency and scale of flooding as well as cultural and governmental characteristics, each country had significant efforts underway to better orient its practices to flood risk realities, including those induced by altered land use and by climate change and variability. The quadric-lateral collaboration was envisioned as a continuing step in international collaboration and as one means for each country to learn from the other countries’ experiences. This document, the result of that collaboration, reflects contributions from agencies within the four participating nations but is not an official position of any government or international organization. The document is organized around a conceptual framework developed to encompass flood risk drivers, risk assessment, and the source-path-receptor concept; the flood risk management cycle with its overarching policies and supporting players and mechanisms; and the adaptive management cycle of maintenance, monitoring, evaluation, and adjustment over time. Differences in scale are addressed through consideration of national and regional/local levels. The document highlights the approaches in each country, the drivers for those approaches, and practices that are working or hold particular promise. Specific examples illustrate various approaches without trying to fully reflect the entirety of any one country’s effort or to include an example from each country for any particular aspect.