Foreword

Irrigation is the largest public investment in many counties in the developing world. The World Bank has played an important role in financing irrigation investments, as total World Bank lending for irrigation amounts to 29 billion US dollars in 1991 prices. Today, the demand for agricultural products - food and fiber - is largely met. This success could not have been achieved without the last half-century's investment in irrigation.

Irrigation will continue to play a critical role in our continued ability to feed ourselves. As demand for agricultural produce increases, driven by population growth and rising income, the bulk of increased production will have to come from irrigated lands. Irrigation supplies plants with water which is often the most critical input to production. There are also strong, positive interactions between irrigation and other major sources of agricultural growth: fertilizer, improved seeds, better husbandry, and integrated pest management.

Water is an increasingly scarce resource, requiring careful technical, economic and environmental management. As the demand for water for human and industrial use has escalated, so has the competition for water used for irrigated agriculture. Thus, the challenge for the irrigation sector is: modernization of irrigation systems and practices, drainage and salinity control, greater attention to cost recovery, measures to reduce pollution from agricultural activities, improvements in the level of service and maintenance of existing systems, investment in small-scale irrigation and water harvesting methods.

This paper deals with the first of these challenges: system modernization. New design concepts and modern technologies already exist and have proven their usefulness in many schemes around the world. What is now required is that these concepts and technologies be assessed and utilized on a larger scale. This publication, which is the first of the new World Bank Irrigation and Drainage Series, is intended to stimulate debate among professionals and to increase awareness of the potential of modern technologies for water control and sustainable irrigated agriculture.

Michel Petit
Director
Agriculture and Natural Resources Department