Spatiotemporal Evolution and Coupling Coordination Between Urbanization and Water Resources in the Minnan Delta Region, China

Despite growing attention to inland water-stressed basins, few investigations have explicitly linked urbanization water resource coupling assessments to the SDG 6 and SDG 11 targets in water-scarce coastal urban agglomerations. Achieving the United Nations Sustainable Development Goals (SDGs)—particularly SDG 6 (Clean Water and Sanitation) and SDG 11 (Sustainable Cities and Communities)—depends critically on sustainable water management in rapidly urbanizing coastal regions. This study examines the dynamic coupling and coordination between urbanization and water resources in the Minnan Delta Region (Xiamen, Quanzhou, and Zhangzhou). We constructed an integrated evaluation index system comprising 16 indicators across urbanization (population, economic, social, and spatial dimensions) and water resources (resource level, utilization efficiency, and conservation) subsystems. Using the entropy weight method and a coupling coordination degree model, we analyzed spatiotemporal evolution patterns from 2014 to 2024. Additionally, the geographical detector model was applied to quantitatively identify the drivers of coupling coordination differentiation. The results reveal that: (1) the comprehensive urbanization index exhibited a sustained upward trajectory, with subsystem importance ranking as economic urbanization > social urbanization > spatial urbanization > population urbanization; (2) the water resources comprehensive index followed a fluctuating yet generally rising pattern, with subsystem contributions ordered as water conservation > water utilization > water resource level; (3) the coupling coordination degree (D) rose from 0.2008 in 2014 to 0.4173 in 2024; and (4) pronounced spatial heterogeneity remained evident, with Quanzhou achieving primary coordination (0.6033), Xiamen reaching barely coordinated status (0.5149), and Zhangzhou remaining on the verge of imbalance (0.4764) by 2024. These findings underscore that sustainable urbanization in water-stressed coastal regions hinges on governance intensity and targeted infrastructure investment rather than on natural water abundance, thereby offering actionable pathways for SDG 6 and SDG 11 localization in similar global contexts, though persistent spatial inequalities necessitate differentiated, city-specific strategies and enhanced inter-city collaborative mechanisms.