Design of Tile Drainage for Arid Regions

The design of tile drainage systems for irrigated zones, primarily in arid regions, is examined. A set of equations sufficient for the determination of the different parameters necessary for the design is given. Because the plants in arid regions rely almost completely on irrigation waters that contain varying quantities of salts, the drainage system should be sufficient to maintain the salt content in the soil within a specified value suitable for plant growth. The treatment is based on the soil properties, the quality of the irrigation water and the salt tolerance of the plants. The treatment of the design in this paper is based on the assumption of uniformity and homogeneity of soil. As this is hardly the case in practice, statistical averages should be taken for the soil parameters involved in the treatment. The salinity of the irrigation water and the salt tolerance of the plants define the leaching requirement.