Floods have been an integral part of the human experience ever since the start of the agricultural revolution when people built the first permanent settlements on the great riverbanks of Asia and Africa. Seasonal floods deliver valuable topsoil and nutrients to farmland and bring life to otherwise infertile regions of the world such as the Nile River Valley. Flash floods and large 100-year floods, on the other hand, are responsible for more deaths than tornadoes or hurricanes. In the United States alone over the past 60 years, an average of 127 people has lost their lives due to floods. Flood-waters are also responsible for billions of dollars in property damage annually.