Modeling agricultural water-saving compensation policy: An ABM approach and application

With the increasing conflict between water availability and demand on a global scale, regulating water user behavior from the bottom-up perspective has gained attention from both water managers and researchers. This paper presents an agent-based model (ABM) to simulate the farmer behavior under changing physical and institutional environments in a case study of Miyun Reservoir watershed, China. The ABM model simulates the complex adaptive systems of agricultural water users under an agricultural water-saving compensation policy. The model we developed in this study characterizes agents' sensitivity, learning capability, and information radius, which impacts agricultural income and water consumption of a household. By applying this model to a local 'paddy to dryland' subsidy policy program aiming at reshaping the agricultural water-saving behavior, the results show that this policy program reduces agricultural water consumption while also reducing household agricultural income. The policy depends on administrative intervention and financial subsidies at first to ensure compliance and gradually shape household behavior in the long run. And we also propose a suitable subsidy range of 250-350 yuan for this policy program in the long run. The model we built can help to understand agricultural water use adaptation to both anthropogenic and environmental interventions. This research also contributes to the coupled natural and human systems study with the bottom-up agent-based model, and the empirical case study provides solid policy implications for the agricultural water use allocation and adaptative management at the watershed scale.