From 1991 to 2007 about 80% of all natural disasters were of meteorological or hydrological origin. In the last decades, between 1960 and 2004, there has been a significant increase in water related extreme events. Floods are the most frequent catastrophic events which people have to face; they are caused most frequently by a coincidence of meteorological and hydrological circumstances but often the flooding of lands has geological or arthritic reasons. As defined, flash floods are a temporary rise of water level in a stream caused by an abrupt increase of discharge or by a temporary decrease of the baneful discharge due to the clogging of the streams channel by ice pack, landslide, etc.
The catastrophic floods are linked with meteorological situations and climate events. Floods depend on the rainfall-runoff relation. Urbanisation causes a tremendous number of changes in this relation by increasing the runoff with increasing impervious areas and storm coverage (Keller, 1976).
It has been reported that flood disasters account for about one third of all natural disasters by number and economic losses. In addition, they are responsible for over half of the deaths associated with such disaster. Unfortunately there is an increasing trend of deaths being due to floods
- To being together scientists, experts, managers and decision makers in order to discuss, deliberate and represent their valuable practices and experiences in different aspects of flash flood management in urban areas with emphasise in arid and semi-arid regions.
- To provide the participants with required information and knowledge related to floods as natural disasters and its impact on water resources management in arid and semi-arid regions in order to work out mitigation strategies to confront with these phenomena.