2018 Volume 31 Issue 5 Pages 337-349
Factors and environmental conditions that lead to successful Participatory Irrigation Management (PIM) have not been identified in the literature. Clarifying a decision-making process of water allocation among farmers is expected to contribute to introduction of PIM. The entire water allocation decision-making process can be changed dramatically by farmers’ water allocation arrangements, which can also change because of a change in environmental conditions. An agent-based model (ABM) is applicable to elucidate such a dynamic process. This study used ABM to structure a water allocation problem to elucidate conditions in which behaviors such as coordination and adaptation emerge among farmers’ organizations. The study area included irrigation blocks in the Saba watershed in Bali, Indonesia. Our ABM was designed to replicate interactions between agents representing Subaks, which are water user organizations in Bali. Furthermore, behavior changes resulting from environmental conditions were compared. Water use of Subak in the upstream block was not interrupted by the other Subaks, but it was influential to the other Subaks, whereas the others used water conditionally. To understand these two patterns of water use, ABM simulated two scenarios for homogeneous and heterogeneous groups. The homogeneous groups had the same water use conditions. The heterogeneous groups had the same water use conditions. Results demonstrated that the heterogeneous groups had more cropping schedules than the homogeneous groups had. This difference of schedules produced erratic water use and structured the water allocation problem. Therefore, to introduce PIM, we propose that extra time be given for water use if a block has users susceptible to any such conditions.
