Floods are important components of the natural hydrological regime. They are a major source of water; they flush pollutants and sediment from river networks. It is also natural for rivers to overtop their banks with greater or lesser frequency and occupy their flood plains. As a result, floods can cause property damage and bring death and injury to many communities. While there is no evidence as yet that the frequency or magnitude of flooding has increased world-wide, flood-prone areas are becoming increasingly more densely populated and thus more vulnerable. Consequently, a series of major flood disasters has occurred in recent years, with death and destruction being caused by such events in every continent..

“The task is not just to preserve water resources to sustain life, but also to reduce the capacity of water to take life away. …we can and must reduce the number and impact of disasters by building sustainable communities that have the long-term capacity to live with risk.”

--Kofi Annan, United Nations Secretary-General (8 October 2003)