Issues in irrigation planning and development

Proper water allocation methods are vital to prevent loss of water while in transit from the source (i.e., reservoir, river, or well) to individual farms. Seasonal water flows, user location vis-a-vis water source (i.e., up or down river), frequency of supply, size of the area to be served, and equity and efficiency in farm-level allocation are important allocation issues for which research is needed. Feasibility studies are required to determine which of the following allocation methods are appropriate for specific projects: (l) unrestricted use for which no formal allocation procedure exists; (2) prescribed shares of water available for specific time periods; (3) unrestricted use in order of location along the irrigation canal; (4) priority use according to the date of farm settlement and/or economic crop value; and (5) consumptive use according to the highest price bid. In project implementation, a country"s institutional and managerial arrangements must be assessed to assure efficiency and equity in irrigation system operation. There are three such institutional types to consider: those that determine the distribution of benefits (local water bureau); those that deal with water distribution and maintenance (water user"s association); and those that make relevant national policies (Ministry of Agriculture). As to irrigation policy alternatives, small-scale projects (i.e., tank irrigation) appear desirable but more information is needed to determine their viability, performance, and operation in the field. To improve system-wide performance, more research is needed on the joint operation of surface and groundwater supplies to ensure optimum use of available water sources, the management of irrigation systems which draw from the same groundwater source, and the effects of certain government policies on the rate at which ground water is drawn. Appended is a 24-item bibliography (l963-78).