ABSTRACT
M a n y c o u n t r ie s in the arid regions, especially developing countries, have undergone extensive developments especially in the agricultural sector to secure the basic national food requirements of strategic crops. Furthermore, the rapid population growth in most of these countries has caused a massive increase in water demands. Unfortunately, the population growth in several parts of the arid regions such as the Middle East is high (2.5%), while the low per capita water supply of 1000 m3/year is expected to drop to half of its present value in just twenty-six years (Jensen, 1980). Satisfying the rising water demands in terms of quality and quantity is a major challenge. In most developing countries, the agricultural demands represent more than 80% of the total water demands (Hennessy, 1993). In some countries such as Mo rocco, Egypt, Oman, Iraq, Sudan, Yemen, and Saudi Arabia, it consti tutes more than 90% (WRI, 1992; Dabbagh and Abderrahman, 1997). Minimizing water losses and reducing irrigation water demands are essential to meeting the expected future increase in food demands along with the limited water supplies in arid countries. It is also important for sustainable irrigation and water resources as major goals. This can be achieved by effective water resources planing and irrigation water management.
