Coupling Coordination Between New-Type Urbanization and Water Use Efficiency: A CAS-Based Feedback Perspective Analysis of Jiangxi and Hunan Provinces, China

Under tightening resource and environmental constraints, exploring the synergy between new-type urbanization and water use efficiency is key to high-quality development in Central China. Using panel data for cities in Jiangxi (11) and Hunan (13) from 2013 to 2022, this study measures the spatiotemporal evolution characteristics of water-coupling coordination in the two provinces. It also incorporates feedback mechanisms from Complex Adaptive Systems (CAS) theory to explain the differences in the evolutionary trajectories of the two provinces from three dimensions: signal strength, transmission efficiency, and bottleneck nodes. The results show the following: (1) The urbanization processes in these two provinces have shifted from a phase of rapid growth to one of steady optimization, and water use efficiency has improved in both. Since 2016, Jiangxi Province has experienced fluctuations, moving from a decline to a recovery, while Hunan Province has seen a steady increase; however, disparities among regions within the provinces persist. (2) The evolutionary trajectories of coupling coordination between the two provinces show marked divergence: Hunan exhibits a pattern of “core responsiveness and peripheral lag,” while Jiangxi displays a “multi-point gradual response”. (3) The barriers in the two provinces are highly similar in nature, focusing on economic scale, capital investment, and labor. Although the same constraints exist, different response pathways lead to distinct patterns—Jiangxi’s passive adaptation results in a diffuse equilibrium, while Hunan’s proactive adjustment results in a polarized gradient. These findings identify two distinct pathways for urban-water system evolution in central China’s water-rich areas, advancing theoretical understanding of system adaptation while providing targeted policy references for regional high-quality development.