In this study, the theoretical review of the development of the Four Major rivers was conducted first. Based on theoretical review of the Four Major rivers’ social-ecological-economic systems, ecosystem services, resilience, and disturbances, the sco ...
In this study, the theoretical review of the development of the Four Major rivers was conducted first. Based on theoretical review of the Four Major rivers’ social-ecological-economic systems, ecosystem services, resilience, and disturbances, the scope of this study was limited and each concept was applied. Next, we explored and typed social-ecological-economic issues related to the development of the Four Major rivers project. In the process of exploring social-ecological-economic issues, a total of 202 articles were collected and analyzed from January 2017 to December 2019, when the issues of re-naturalization emerged as a hot topic. The articles were analyzed for the pros and cons of the Four Major rivers development, the green algae issues, the pros and cons of re-naturalization, and the pros and cons of opening the weirs. As a result of the analysis, about 50% of the articles opposed to the development of the Four Major rivers accounted for the reason, and the Four Major rivers were the cause of the articles mentioning the green algae. In addition, there were positions in favor of re-naturalization, and accordingly, the trend of supporting the opening of the weir was also shown. Based on this, major variables in social, ecological and economic aspects were derived and the impact of the Four Major social-ecological-economic systems were analyzed.
Next, we explored the feedback structure of the social-ecological-economic systems following the development of the Four Major rivers. First, the feedback structure was analyzed in terms of water resource use and aquatic ecology conservation for the conflict structure that appeared after the development of the Four Major rivers, and the conflict and dilemma structure were identified accordingly. In terms of water resource utilization, the system for agricultural water and flood control due to weir installation was analyzed. In terms of aquatic ecology conservation, the system was analyzed focusing on green algae phenomenon and other water pollution. The dynamics of conflict and policy dilemma structure in the re-naturalization policy determined accordingly were analyzed. In addition, the causal feedback structure was analyzed for the resilience of ecosystem services due to the development of the Four Major rivers. The variables were derived from the provisioning services, regulating services, cultural services, and supporting services among ecosystem services, and the resilience of ecosystem services was analyzed accordingly. In the process of analysis, trade-off between ecosystem services and trade-off within each ecosystem services were analyzed. Based on the analysis and resilience principle, the plan to improve resilience of ecosystem services in the Four Major rivers was presented. Also, the feedback structure that occurred before and after re-naturalization of the Four Major rivers was analyzed in terms of agricultural water and water quality.
Based on the causal loop feedback structure analyzed, the resilience model of the social-ecological-economic systems according to the development of the Four Major rivers was developed and simulated and suggested policy alternatives. For this, we collected monitoring data for 16 weirs of the Four Major rivers and analyzed them. The stock-flow diagram of the Four Major river resilience prediction model was constructed based on the collected data. The model was built around the hydrological, water quality, ecosystem, and social sectors. In terms of hydrological, the model was constructed with a focus on low water capacity and water level, and in the water quality side, the algae concentration, T-P and BOD were formed. In terms of ecosystem, the model was constructed based on sandy area, health index of fish, and bird population. In terms of social aspect, the model was constructed based on amount of intake and power generation. The model simulation was conducted for Sejong weir and the changes in hydrology, water quality and ecosystem were predicted after the full opening of Sejong weir. Through the water quality improvement policy introduced to Sejong weir, we tried to solve the problem of water quality that occurred after the opening of Sejong weir. Finally, through the policy alternative based on the simulation results, we proposed a policy that can stabilize and maintain the social-ecological-economic systems after the Four Major rivers re-naturalization policy.