本文提出了基于水资源-生态系统-经济社会三者之间状态的水平衡综合诊断方法。构建了基于水平衡原理的分析框架，以自然水收支、社会经济供需、河道内生态和社会生态竞争四大平衡为基础，量化了南水北调西线工程潜在水源区的水平衡状态。研究结果表明，2005至2020年间，西线工程水源区生态系统维持了较为稳定的水量平衡，区域内水资源、社会经济与生态系统的协调性稳步提高，耦合协调度提升，水资源管理、生态保护与社会经济发展间的协同效应显著，反映出水资源管理和生态保护成效显著。研究结果可为源区水资源综合管理和调水工程政策制定提供参考。

This study aims to develop a comprehensive diagnostic method for evaluating the water balance state of water resources, ecosystems, and socio-economic systems in the context of large-scale water management projects. The focus is on the potential water source areas of the South-to-North Water Diversion West Route project, analyzing the interactions between natural water balances, socio-economic demands, and ecological considerations. The research centers on quantifying and assessing the coordination and sustainability of these systems in the West Route’s water source region from 2005 to 2020. An analytical framework based on the principles of water balance was constructed, incorporating four key components: natural water supply and demand, socio-economic water needs, ecological water consumption, and the competition between ecological and socio-economic systems within the river basin. This framework was used to quantify the water balance status by evaluating water availability, ecological functioning, and socio-economic demands over the period of study. Statistical methods and multi-dimensional analysis were applied to calculate the coupling coordination degree, which measures the extent of coordination between water resource management, ecological protection, and socio-economic development. The study relied on regional hydrological records, socio-economic data, and ecological assessments to ensure robust and reliable results. The findings reveal that from 2005 to 2020, the water balance of the West Route’s water source areas has remained relatively stable. Importantly, the region has maintained a steady equilibrium in water resources, with significant improvements in the coordination between water resources, socio-economic development, and ecological systems. The coupling coordination degree between these three systems has shown a clear upward trend, reflecting the growing harmony between water management, ecological conservation, and socio-economic growth. The research highlights that the ecological system within the water source areas has effectively adapted to changes in water availability, demonstrating resilience in sustaining water use. Moreover, there has been a substantial positive synergy between water resource management and ecological protection, which has contributed to the stability and improvement of the regional water balance.Additionally, the study shows that the competition between ecological and socio-economic water demands has become more balanced, shifting toward a more integrated approach. The region’s ecological protection strategies have become better aligned with water resource management policies, resulting in improved sustainability in both ecological and economic terms. The findings suggest that enhanced water use efficiency, combined with adaptive ecological protection measures, has played a pivotal role in achieving these positive trends. This research offers significant insights into the water balance status of the West Route’s water source areas, emphasizing the progress made in achieving coordinated development between water resources, ecological systems, and socio-economic activities. The study’s innovative approach—integrating natural water balance, socio-economic factors, and ecological needs—provides a comprehensive framework for evaluating the sustainability of water resources in large-scale inter-basin water diversion projects. The findings demonstrate that coupling water resource management with ecological protection is not only feasible but essential for ensuring the long-term sustainability of water source areas.The results indicate that the West Route’s water source areas have achieved a significant degree of ecological and socio-economic coordination, which is crucial for ensuring the effectiveness of future water diversion projects. Furthermore, the increase in coupling coordination reflects the positive outcomes of integrated management practices that simultaneously address water resource conservation, economic development, and ecological sustainability. These findings serve as a valuable reference for policymakers involved in the comprehensive management of water resources in source regions and offer a foundation for formulating policies that support the long-term sustainability of large-scale water projects like the South-to-North Water Diversion.In conclusion, this study underscores the importance of adopting an integrated approach to water resource management, one that recognizes the interdependencies between natural, economic, and ecological systems. The research highlights that coordinated water management, paired with adaptive ecological conservation strategies, is critical to achieving sustainable development and ensuring the resilience of water source areas in large-scale water transfer projects. Furthermore, the study suggests that such integrated management models can serve as a blueprint for other regions facing similar water resource and environmental challenges, ultimately supporting the global pursuit of water sustainability.