The Assessment of Egypt’s Subsurface Drainage System

Drainage is the removal of excess water and salt from the soil at a rate which will maintain soil structure and aeration in order to permit normal plant growth. Several studies have indicated that water-logging and salinity problems arise as a result of poor water management and inadequate water table control in irrigated agriculture. At the turn of the nineteenth century, perennial irrigation was introduced in the Nile River Delta and Valley of Egypt. The natural drainage in many areas is not enough to account for the excess irrigation water. This has led to a raise in the groundwater table, and increases problems of water-logging and salinity. These problems have serious effects on crop production in arid and semi-arid regions. Many countries which are traditionally famous with their irrigated agriculture, like in Egypt, have realized that the absence of adequate drainage is the reason for the decline in crop production. Therefore, they have undertaken large-scale projects to install drains to conserve the productivity of the agricultural areas. There are three types of drains for removing excess water. These include open drains, subsurface drains, and tube well drains. Each type has advantages and disadvantages. In Egypt, subsurface drains are preferred because of their long effective lifetime ‘when adequately designed and properly installed’, the gain of land, and the comparatively low maintenance cost. A detailed discussion of subsurface drainage techniques in Egypt is provided in this chapter.