UN Economic and Social Development
Division for Sustainable Development

Executive summary:

Floods have the greatest damage potential of all natural disasters worldwide and affect the greatest number of people. On a global basis, there is evidence that the number of people affected and economic damages resulting from flooding are on the rise at an alarming rate. Society must move from the current paradigm of post-disaster response. Plans and efforts must be undertaken to break the current event-disaster cycle. More than ever, there is the need for decision makers to adopt holistic approaches for flood disaster management.

Extreme flooding events are not relegated to the least developed nations, but can also devastate and ravage the most economically advanced and industrialized nations. In the last decade there has been catastrophic flooding in Bangladesh, China, India, Germany, Mozambique, Poland, the United States and elsewhere. When floods occur in less developed nations, they can effectively wipe out decades of investments in infrastructure, seriously cripple economic prosperity, and result in thousands of deaths and epidemics. The majority of the deaths associated with such disasters can be found within the most vulnerable members of society, namely women and children. The greatest tragedy is that most of these deaths, associated post traumatic stresses, and social and economic hardships can be either avoided or dramatically reduced through pre-, during, and post-disaster investments in preparedness activities and associated infrastructure, flood plain policy development, effective watershed land use planning, flood forecasting and warning systems, and response mechanisms.

It is recognized that comprehensive assessments of risks from natural hazards such as flooding, mud/land slides, and extreme wind and rain are necessary for society to better understand the risks which they face daily. Assessment of risk and the involvement of the community in the decision making, planning and implementation process can help lead to sustainable solutions. Solutions must reflect the human dimension and must also consider the impacts of changing land use on flooding, erosion, and landslides. Integrated water management practices must be embraced. Societies have much to learn from new approaches such as better forecasting techniques and applying experience gained from flood events and mitigation efforts employed elsewhere. Implementation will only be sustainable if solutions are suitable for the community at risk over the long term. As storms will continue to occur, risk assessment and planning followed by actions are needed to help reduce the overall risk to society, the economy and the environment.

These guidelines are oriented to the needs of the decision-maker and provide a description of the range of mitigation options that need to be considered when making efforts to reduce losses from flooding. The guidelines are designed to provide an introduction to the general area and to introduce the reader to various measures to mitigate the impacts associated with floods. A bibliography is provided that cites detailed material available for the planning and implementation stages. These guidelines are not meant to address floods resulting from storm surge, ice or debris jams, or the failure of human-made structures.