equal to or better than that of the groundwater, and water quality should be regularly monitored.

Water demand management. Options for managing water demand include technical, financial and economic measures, public awareness and active public participation in addition to institutional and legal measures (Gleick, 2000; Baroudy et al., 2005). Technical options for demand management include improving water infrastructure, rehabilitating existing water conveyance and distribution systems, lining earth ditches with concrete or other materials, replacing irrigation ditches with pipelines where affordable, rehabilitating old irrigation wells, rehabilitating hydraulic structure and irrigation networks, and installing water-measuring devices. At farm or field level, shifting to more efficient irrigation systems, improving irrigation practices, irrigating with proper scheduling, using unconventional water sources, cultivating more drought- and salinity-tolerant crops, and diversifying production systems with new crops and rotations that are more conservative in water use (Hillel, 2000) may reduce water demand considerably. Knowledge and understanding of farmers with regard to water-efficient technologies and practices will therefore have to be strengthened and increased.

However, besides technological options, demand for water will also have to be reduced through economic, administrative and social mechanisms (Baroudy et al., 2005). Whereas incentives may encourage investments into waterefficient technologies, water tariffs and water prices have a direct effect in controlling demand. In CWANA, farmers often have little reason to save water because irrigation water is easily accessible and farmers do not have to pay much for the water they use. Water-pricing policies may thus be efficient in general but remain highly controversial in the region. Therefore, water pricing should be used within a comprehensive framework to follow an IWRM approach in managing water resources. Usually water pricing includes the cost of water treatment where required, distribution and conveyance. It is important that water-pricing policies be developed with the participation of water users.

Financial and economic measures should be governed by two main principles: the user-pays principle and the polluter- pays principle. The water value should exceed the marginal cost of extracting and distributing the water. Water tariffs should be based on the full economic cost of the water; they should cover full operation and maintenance costs for the system. Flat tariff systems should be eliminated and farmers should be charged according to their actual consumption of water. Being charged by water consumption per unit area for irrigation gives farmers incentive to improve their water-use efficiency. Water cost from different sources and for different areas should be calculated according to the same principles.

Raising the degree of public awareness about rational water use and consumption patterns is important for effective demand management. A more promising approach than simple public campaigns is to strengthen the public’s participation in controlling water demand and use, i.e., decentralization and participation in decision making regarding water management. Devising appropriate institutional frameworks adapted to the specific requirements and

conditions of each country can establish and empower water-user associations, which have proven to increase water users’ awareness and responsibility.

Virtual water trade. “Virtual water” is the water used to produce an agricultural product. Trade in agricultural products is thus also trade in virtual water. Trade of virtual water at national and particularly at international levels may reduce the pressure on scarce water resources and improve water-use efficiency globally (see World Water Council, 2004). By importing products requiring large amounts of water for production from areas with abundant water resources, water-scarce countries and areas may reduce the pressure on their own water resources and thus make water available for other purposes—the principle of comparative advantage. If the goods are imported from countries where less water is required to produce them, the global productivity of water may be increased. Since pressure on water resources may be eased through virtual water trade, investments in developing new water sources (such as dams or water transfer) may be reduced and negative side effects thereof diminished. Furthermore, the potential for conflict over water, which is particularly prominent in CWANA, may be reduced through virtual water trade (Allan, 2002).

However, virtual water trade also bears potential risks and drawbacks. These include ecological aspects (related transport, nutrient transfers, sustainability of production in exporting countries, alternative land use in importing countries) and economic concerns (how to afford imports; effects of imports on local agricultural production, rural development and consumer prices). Furthermore, opportunity costs of land and labor, as related to high unemployment rates, will have to be considered carefully in designing policies relating to virtual water trade. The greatest obstacle to the concept, however, lies in sociopolitical aspects, particularly in the geopolitical situation of most CWANA countries. People and countries are in general reluctant to become dependent on food imports; they may feel they will become restricted in autonomy and self-reliance. Thus implementing the virtual water concept requires consideration of important national goals such as food security (self-sufficiency or self-reliance), national security, economic growth and development (including poverty reduction, employment opportunities) and the quality of life in general. The virtual water concept may thus foster a more holistic approach to managing water resources, by linking water, food production, trade, consumption, food security, etc. It is a useful theory for developing policies targeting more productive water use and rational water-resource management.

However, research is still required to fill knowledge gaps on potentials and risks related to the concept. In addition, agreements on enabling framework conditions would have to be elaborated and implemented at the international (WTO) level. Such agreements would have to consider political, social and ecological aspects, assure the food security of importing countries and provide protection from abuse of dependencies through blackmail (Studer, 2005).

5.2.2.2 Soil and land

Since productive soil is the basis for agricultural production, soil and land degradation directly affects agricultural