Evolutionary Characteristics and Obstacle Factors of the Water–Energy–Food Nexus in Resource-Based Regions: A Case Study of Daqing, China

The water–energy–food (WEF) nexus is central to regional sustainable development, particularly in resource-based regions (RBRs) facing resource depletion and ecological strain. While existing studies have examined internal WEF linkages and extended the framework to include external dimensions such as ecology and land, the stage-based succession of limiting factors across developmental stages has received limited attention, and resource-based cities in which energy and grain production functions coexist remain underexamined. Taking Daqing, a typical resource-based city in China, as a case study, this paper constructs a comprehensive evaluation index system covering water, energy, food, and regional development subsystems. The CRITIC method is adopted to calculate indicator weights, and the coupling coordination degree model is applied to analyze the evolutionary characteristics of the WEF system’s coordinated development over the period 2005–2023. The obstacle degree model is further employed to identify obstacle factors across different stages. The results indicate that the comprehensive evaluation index experienced three evolutionary stages: rapid growth, structural adjustment, and recovery and improvement. The coupling degree remained at a high level, increasing from 0.915 to 0.999, while the coupling coordination degree rose from 0.508 to 0.789, evolving from borderline coordination to moderate coordination. The dominant obstacle factors exhibit notable succession characteristics, shifting from energy and water constraints to food subsystem pressures, and finally to water supply–demand imbalances. The coordinated development of Daqing’s WEF system is driven by three core forces: the oil and gas industry cycle, water resource regulation policies, and grain planting structure adjustments. These findings provide theoretical references and practical implications for optimizing resource management and advancing sustainable development in RBRs.