Urbanization and Water Resource Green Efficiency: Coupling Coordination, Dynamic Interactions, and Driving Forces

Urbanization promotes economic growth but also increases water demand and water pollution. Therefore, the coordinated development of the two is a central issue for regional sustainability. Focusing on the Yangtze River Delta during 2003–2022, this study evaluates the level of urbanization and water resource green efficiency (WRGE). The Coupling Coordination Degree Model was employed to examine the coupling coordination degree between urbanization and WRGE. The results show that urbanization steadily rose with apparent regional disparities, while WRGE initially declined and then increased, with significant urban agglomeration effects, and the coupling coordination degree shifts from Mild to Primary Coordination. Furthermore, the Panel Vector Autoregression model exhibits that both urbanization and WRGE show self-reinforcing dynamics and mutually reinforcing effects, although the magnitude of these impacts weakens over time. Tobit analysis indicates that coupling coordination degree is hindered by technological innovation, water resource endowment, and openness to foreign investment, but promoted by economic development, industrial structure, and water conservation awareness. These findings are vital for narrowing regional disparities and fostering sustainable development.