ABSTRACT
Abstract The West Bank is suffering from severe water scarcity: the resources are limited and the demand is increasing. Agriculture is the biggest water consumer as it accounts for 70% of the total water consumption. Therefore, effective agricultural water management is key to achieving water sustainability in the area. This study aims at optimizing irrigation water allocation using a linear mathematical programming model. The analysis was applied in five agricultural zones in the West Bank and included four main vegetable crops namely tomato, cucumber, eggplant, squash and citrus. Three scenarios were analyzed in the study: The first scenario presents the existing cropping patterns, the second maximizes profit under water and land availability constraints and the third one maximizes profit under constraints of water and land availability and local crops consumption. Results of the study showed that changing the cropping patterns of the five crops included in the study under land and water availability constraints reduces the water used for irrigation by 10%, which is equivalent to a reduction of 4% of the total agricultural water use. This would increase the total added value from these crops by 38%, equivalent to 4% of the entire agricultural sector. With regard to scenario 3 the reduction of water use for irrigation was also 10% and the increase in added value was 12% for the studied crops and 1% for the entire agricultural sector. It was concluded that water scarcity can be approached by changing the cropping patterns according to their water use. Key words: Agriculture, cropping patterns, linear programming, profit maximization, water scarcity. 4.1 Introduction and background 4.1.1 General With continuous population and economic growth, water resources have become increasingly scarce in a growing number of countries and regions of the world. As the largest water user, food production is directly constrained by water scarcity (Yang et al., 2006). Several authors (Rosegrant et al. 2002; Playan and Mateos, 2006; Yang et al., 2006; Falkenmark, 2007) in discussing the capacity of the earth to produce food for its increasing population, argued that one of the main factors limiting further expansion of food production will be water. This scarce resource is facing heavy and unsustainable demand plus pollution which decreases water quality and, therefore, availability. The West Bank, as many areas of the Middle East, is suffering from a severe water scarcity. The water use of Palestinians in the West Bank is 50 m3/cap/year, withdrawn from water resources available in the area. This water is used for domestic, industrial and agricultural purposes. 70% of the water is used for agriculture. Therefore, the West Bank is badly in need of improved water management in the agricultural sector in order to obtain the optimal benefits from the scarce water resources in the area (Nazer et al., 2008).
