Coupling Relationship Analysis of Water Resources, Society, Economy, and Ecosystems in the Shule River Basin

Climate change and human activities have intensified the imbalance between water supply and demand in the Shule River Basin. Prominent issues such as groundwater over-exploitation and insufficient ecological base flow have significantly constrained the high-quality development of the region. An evaluation system was developed comprising 20 indicators across four subsystems: water resources, society, economy, and ecosystems. The entropy weighting method was employed to determine the weights of each indicator. The coupling coordination degree of the water resource–society–economy–ecosystem system from 2003 to 2022 was assessed using a coupling coordination degree model. Network analysis was applied to evaluate the correlation and connectivity among indicators. A barrier diagnostic model based on indicator deviation was further constructed to identify key constraints within the system. The results showed that the overall coordination degree of the coupled system increased from 0.217 in 2003 to 0.409 in 2022, shifting from a moderately uncoordinated state to a weakly coordinated one. However, the coordination level remained low due to fluctuations in the water resource subsystem. The ecological and economic subsystems functioned as critical coupling hubs, while strong negative interactions within the water resource subsystem emerged as major constraints to coordinated development. Long-term dominant barriers included the proportion of water used for ecological and agricultural purposes, as well as per capita food production. After 2019, water resource-related indicators, such as per capita water availability and water production modulus, showed a marked increase in obstruction levels, highlighting the persistent challenges posed by water scarcity and inefficient utilization.