Evaluation of water-economy-ecology system development level and coupling coordination degree: a case study of China’s central plains urban agglomeration

The water-economy-ecology (WEE) system exhibits a complex coupling relationship, presenting significant challenges to sustainable urban agglomeration development. This study proposes a novel evaluation framework to explore the coupling coordination degree (CCD) of the regional WEE system for sustainable urban agglomeration development. By integrating the EFAST-Cloud model (ECM) to quantify the comprehensive development level of each subsystem, and applying an improved coupling coordination degree model (ICCDM), the spatio-temporal evolution of CCD in China’s Central plains urban agglomeration (CPUA) was analyzed. Results indicate: (1) The comprehensive evaluation index (CDI) of the WEE system shows an upward trend, with Xinyang, Zhengzhou, Huaibei, and Jiyuan in the leading position in their respective subsystems and the WEE system. (2) From 2011 to 2020, CCD exhibited a fluctuating but increasing trend, with the dominant coupling relationship shifting from water-economy to water-ecology. The core development area (CDA) consistently outperformed the non-core area (NCDA), with Jiyuan, Huaibei, and Zhengzhou achieving the highest CCD values. (3) Spatial analysis indicated a gradual strengthening of global spatial autocorrelation, while local autocorrelation was dominated by L-L and H-L clusters with limited spatial extent. The gravitational effect of CCD became increasingly pronounced by 2020, with Zhengzhou consistently emerging as the dominant center of gravity (COG) for CCD distribution. This study could not only provide a robust methodological framework for WEE system research but also offer new theoretical and practical insights into sustainable development in urban agglomerations.