Manual - Participatory rapid diagnosis and action ... - FAO.org

22 Chapter 3. Constituents of irrigated agricultural systemof irrigation farming, production means and land tenure status may lead todifferences in plot use.Water circulationPlot useWater distribution based on rotation assumes that farmers will get water fortheir plots according to a fixed schedule and that they plan their activitiesrigorously.Farmers may make changes to the initial water distributionschedule according to their time and labour constraints. Over-estimationof water use efficiency at the design stage may result in water scarcity anduncertainty of water delivery at plot level. This may lead to changes in plotuse and, in some cases, plot abandonment.Example 3: Interaction between “Irrigation Scheme” and “Organization”.Water CirculationOrganizationDesigned water circulation has a direct impact on organization. Distributionof water is a task the organization must implement.Maintenance of earthen canals may be very demanding to the organization.Insufficient maintenance often leads to decrease in canal discharge capacityand subsequent changes in the water distribution schedule leading to possibleconflicts between water users.The type of water distribution and regulation structures determines the extent towhich the organization has to define rules for water distribution. In some cases theorganization has to appoint persons in charge of manipulating these structures.Example 4: Interaction between Organization and plot use.One objective of the organization may be the planning of the cropping seasonthat has a direct impact on plot use (cropping calendar). On the other hand,individual farmers may decide themselves on the type of crops and seasonalcalendar and request the organization to make changes in the water distribution.Irrigation requirements of individual farmers may differ according to the typeof crops and type of soils of individual plots.Questions to be answered during the Rapid DiagnosisAt the Rapid Diagnosis stage, data that are difficult to collect (i.e. agriculturalyields, water use efficiency) should be roughly estimated. Priority is given towell-reasoned explanations of farmers’ practices to set a qualitative picture of