Modeling the integrated framework of complex water resources system considering economic development, ecological protection, and food production: A practical tool for water management

Abstract. The rapid increase of population and urbanization is accelerating the consumption of the water resources that play an essential role in economic development, ecological protection, and food productivity (EEF). This study developed an integrated modeling framework to better identify the dynamic interaction, coevolution process, and feedback loops of the nexus across EEF systems by incorporating the multi-objective optimization and system dynamic (SD) models. The multi-objective model optimizes the water allocation decisions considering the adaptive status of both the whole system and each agent, while the SD model discloses the dynamics of the coevolution process and reciprocal feedback of the EEF system. The framework is applied to the Upper Reaches of Guijiang River Basin, China, in the context of interconnected systems considering the agents of economic development, ecological protection, and food productivity. Results show that the proposed framework enables the optimal water allocation decisions in each time step, and the SD model can adequately reveal the coevolution process and reciprocal feedback that differs in different stages in integrated, dynamic ways. The rapid economic growth intensifies the ecological awareness that cannot support such rapid development because of the conflict between environment and economic water uses. Once the economic growth rate decreased, water resources are able to support economic development because the ecological awareness is alleviated in this respect. The different water usages demonstrate the competitive mechanism, and the river ecological agent is the critical factor that affects the robustness of the model. The equal consideration of each water usage is the most beneficial to sustainable development. These results highlight the importance of water resources management considering multiple stakeholders and tradeoffs and give an insight into future dynamic changes of complex water systems.