Deals with the productivity of irrigated agriculture but, at the same time, emphasizes the importance of equity in irrigated systems. Suggests irrigation potentials may be expanded through the construction of new projects; rehabilitation and modification of the infrastructure in existing projects; modification of the operation and maintenance of irrigation infrastructure; and implementation and enforcement of rules and regulations governing the use of irrigation facilities. Encompasses a range of possibilities for enlarging and making more equitable the use of existing irrigation water supplies. Employs as illustrations projects in which decisions are made to redesign the infrastructure so as to allocate larger and more regular water supplies to more powerful irrigators; and enforce less rigorously rules and regulations against more powerful irrigators. Reviews literature on the role of water management in agricultural development and offers an explicit discussion of equity-based water reform. General principles, suggestions of organizational structure, and an overview of the Philippine Irrigators' Service Associations, and implementation possibilities, are offered.