April 21, 2009
Background
 
 
The water resources issues, in particular, have been recognized as an international priority by all experts. The UNESCO has given special attention to water resources management in arid and semi-arid region by devoting and giving priority to the IWRM in the fifth and sixth cycles of its hydrological program (IHP-V, VI). and will do the same in the seventh IHP (IHP-VII). The middle east region has placed the water resources issues in the top of their national and regional agenda. ​
 
The severe pressure on water resources in the Arab countries has raised the attention on the appropriate management of renewable water resources. Management of flash floods for beneficial use in Wadi areas through flood mitigation and water harvesting schemes are usually considered of an increasing importance for these areas. Underlying these issues is a need to establish a sound scientific basis for managing Wadi systems and to develop suitable tools for design and management practices for the harnessing and avoiding hazard related to flood water in wadis.
Wadi systems cover about 35% of the total area of Arab region. Coarse alluvial deposits made of sand and gravel that from traction load during wadi flows provide the best water-bearing units in shallow environments. In countries suffering from arid to extremely arid conditions, replenishment of such deposits occurs from seasonal surface flows (short duration flash floods and/or base flows). This process takes place in regions where to combined effects of climatological, hydrological, physiographical, and geological characteristics are favorable not only for generating large volumes of runoff water but also for transporting it as well to major wadi areas.
Wadi is the Arabic name given to a seasonal or ephemeral water course in the arid region and increasingly is recognized as an international name used in most hydrological publications all over the world. In spite of its great role as a vital source of water supply, a natural drainage system, as well as a source of threat of catastrophic flood in many Arab countries, the scientific understanding and knowledge-base of its hydrological processes are rather poorly understood in most of these countries. Thus, the IHP “Wadi Hydrology” programme aims mainly to increase the knowledge and understanding base needed for sustainable management of water resources in arid and semi-arid areas