ing excess rainfall years from evaporation. The reservoirs do not shrink in size. The only risk is pollution by compounds that are not stopped while the water is traversing the porous environment during infiltration. Many countries have converted some dams to refill groundwater. The El Aouareb Dam on the Merguelill, in Tunisia, now is managed to release water to refill the water table in the Kairouan Valley downstream. This experiment, which interests all countries in the region, is monitored within the research network, "Wadi Hydrology," of the International Hydrological Program of UNESCO.

The karstic systems of limestone rocks also show potential for storing water. The Figeh source, which supplies some potable water to Damascus, has a flow of 20 to 30 m3 s-1 in winter and only 3 m3 s-1 in summer. The plan is to stock the winter surplus, when demand is only 15 m3 s-1, in the subsoil (Miski and Shawaf, 2003). A technical study on this is now under way and more scientific research is proposed with the European Union's programs.

Institutional reinforcements: From past experience, emergency programs in case of drought should revolve around the following points:

• Provide potable water to cities and countryside and water to livestock
• Safeguard livestock using knowledge of the forage deficit
• Provide financial support for farmers most affected by the drought
• Provide seeds to farmers, keeping in mind that employment in the countryside prevents rural and agricultural exodus

To plan and implement these programs, governments should set up structures to forecast and identify droughts. They must have access to diverse, reliable data sufficiently processed to be easily interpreted by decision makers. Such information is either a forecast or an observation. Forecasts deal with climate trends, precipitation, evaporation, water that is available and collectible, grazing ranges and harvests. Observations are made at the first sign of the drought and deal with the crisis in each region and on the efficiency of the measures implemented; they must be made during the entire drought to better prepare for future droughts.

In an FAO study on planning antidrought strategies in Morocco, M. Bernardi (1996) recommends a four-level structure where the roles of each entity are well defined:

• A base includes the information providers who regularly monitor key indicators and forecasts (Agrometeorological Committee on Drought Monitoring)
• A second level determines the impact of the drought on different sectors in country (Drought Impact Evaluation Committee)
• A third level proposes measures based on the information received (Drought Monitoring Cell)
• A top level, the prime minister's cabinet, in coordination with the planning, finance and agricultural ministers, authorizes emergency actions and proposes mediumand long-term intervention plans to the government to mitigate the effects of the drought

The strategy depends greatly upon the first level, where tools remain the least effective and to which AKST could contribute greatly:

• Long-term forecasting: Reliable information on future seasons would facilitate preparing and executing the most effective policies to combat drought. The investments and international support needed to mitigate its effects should be foreseen and mobilized. Long-term forecasting always is difficult and remains at the continental and regional scale. On the northern shores of the Mediterranean, many programs have been started to research the consequences of global warming on water flows and on their new distribution amid the water cycle (European Environmental Research Programs).
• Medium-term forecasting: Medium-term forecasting is the area with the greatest expected benefits. These benefits are rapid alert systems, the rationalization of planning for strategic cereal reserves and improved exchanges of foodstuffs among countries. This gives governments the possibility of integrating climate variability into economic management (Bernardi, 1996). This forecasting relies particularly on hydraulic infrastructure, meteorological and hydrological networks and observation of agricultural production and range. WMO, UNESCO and Sahel and Sahara Observatory (OSS) programs encourage sharing information and forecasting: Med Hycos program, Alpine and Mediterranean Hydrology (AMHY) program and the environmental observatories of the Long Term Ecological Monitoring Observatories Network (ROSELT).
• Short-term forecasting: Forecasting during a single season is fundamental to improving forecasts for filling dams, the level of underground water tables and crop yields. Better performing models, with high spatial and temporal resolution, could furnish more reliable information during a season. This information, integrated with other data such as zones and land use, is the base of an early alert system. Progress in satellite imagery and in geographic information has contributed greatly to the development of these models.

2.2.5.5 Environmental policies and regulations

Environmental problems in CWANA are desertification, deforestation, rarefaction of water resources, pollution and disease and pest epidemics. They result from human activity, technical change and climate change. Global warming could drastically change the world's agroecological zones and destabilize weather patterns, leading to an increase in incidence of severe disasters, such as drought. The environmental problems of intensive and high-input agriculture are recognized globally. In the region, the main environmental problems related to agriculture are linked to farm mechanization (soil erosion), irrational use of chemical inputs and pesticides (water pollution) and irrigated farming (overexploitation of groundwater and salinization)

The increased awareness of the challenges to environmental sustainability has led to environmental regulations and policies, which, however, are unequally implemented by the CWANA countries. In several countries, measures are being taken to diversify agricultural practices and improve efficient resource use. Crop diversity will supply use-