Exploring the coupling coordination relationship of water resources, socio-economy and eco-environment in China

Water resources (W), socio-economy (S), and eco-environment (E) have incredibly intricate linkages of interaction, and the coordination of them is crucial to the long-term sustainability of a nation. Thus, we considered "water resources, socio-economy, and eco-environment" (W-S-E) as a composite system and constructed an evaluation model to quantitatively analyze the coupling coordination degree (CCD) of W-S-E system in China from 2011 to 2020. Then, the spatial correlation characteristics were analyzed by using spatial autocorrelation method. To analyze the time evolution patterns of the W-S-E system, this paper divided the stages from the perspective of clustering, which is more scientific and interpretable than the CCD fixed-value division. We found that: (1) W subsystem, S subsystem and E subsystem were closely connected and its CCD was enhanced with relatively higher growth rates in the development of S subsystem but slower growth rates in the W subsystem. (2) The CCD of W-S-E system had spatial correlation. The areas with low CCD were concentrated in the west of China, forming poor coordinated development phenomena. Conversely, most of provinces had relatively high CCD in the east of China with the coastal region playing radiative driving function. (3) The temporal change of W-S-E system followed four transforming patterns including "policy-oriented type", "resource problems constraint type", "socio-economy leading type", and "special location controlling type". Furthermore, we also put forward some advice and policy suggestions. The findings provide research basis and guidance for the sustainable and coordinated development of water, society and ecology.