This book is devoted to the shortage of readily available water for irrigation. It will assist the irrigation/civil engineer in designing the structure of a diversion weir without needing other specialized subject books. This book stems out of the author′s own experience in several developing countries. Diversion weirs are the most important component of irrigation projects. The diversion weir is a piece of engineering work which needs careful design and thorough hydrological, hydraulic and structural analysis. In most developing countries, it is now realized that the most important factor in the success of agricultural sector economy is the sustainability of irrigation projects.