Characteristics of virtual water transfer networks and their influence on the spatial equilibrium of water resources in China

• A multilayer, city-level VWTN for China was constructed. • The overall VWTN forms a “three horizontal and three vertical” flow pattern. • The community structure of the Pro VWTN closely aligns with economic zones. • Virtual water transfers have improved the spatial equilibrium of water resources. Rapid economic development and increasingly frequent trade flows have disrupted traditional resource allocation patterns, triggering large-scale virtual water flows. An in-depth exploration of virtual water transfer networks (VWTNs) will allow for accurately assessing local water resource demands and measuring water resource pressures. However, studies lack a comprehensive analysis at the large-scale city level, hindering the efficient and precise allocation of water resources. In this study, we employ input–output modeling and complex network analysis to construct a multilayer VWTN among 313 cities in China, quantifying key network characteristics such as node strength, connectivity, and centrality. Results demonstrate that VWTN flow size and geographical distribution vary significantly across sectors. The overall VWTN (i.e., Production (Pro) VWTN) forms a “three horizontal and three vertical” flow pattern, characterized by intraprovincial macrocirculation and interprovincial microcirculation. The community structure of the Pro VWTN closely aligns with the distribution of existing urban agglomerations. Additionally, virtual water transfers have improved the spatial equilibrium of water resources, as evidenced by a 0.08 decrease in the Gini coefficient between water resource volume and the permanent population. This study provides a basis for scientifically optimizing water resource allocation and management and offers new ideas and methods for formulating related policies and practical applications.