ABSTRACT
In view of the growing importance of drainage to sustain the irrigation areas that are the "food machine" of the arid zone, and in view of the level of ignorance of the technical, financial, econometric, social, political, legal, and administrative aspects, there is clearly a fertile field awaiting basic and applied research. Drainage engineers have to determine the best technical means of obtaining water table control and the optimum depth to the water table. Conventionally, drainage of irrigated land is considered to be a collective good that cannot be economically undertaken by individuals. Private investments in drainage are likely to be most critically evaluated by farmers, and, as a result, the form and extent of drainage will be more in line with market-signal benefits than will public schemes. The main technical alternatives for irrigated land drainage being considered in Pakistan are horizontal drains and vertical drainage with tubewells.
