This book is primarily meant for undergraduate and postgraduate students of agriculture, horticulture, forestry, and agricultural engineering. It would also be useful for agronomists, irrigation engineers, agricultural engineers, ecologists, agricultural meteorologists, agricultural officers, and all others working in the field of water management. In short, the book has been moulded with two major objectives, to serve as a textbook for teaching “irrigation and drainage” or “water management” and to serve as a handbook for those involved in research and extension activities related to water management in agriculture. The stress is, however, directed towards small holder irrigation in the tropics.