Research on the fairness and risk transmission mechanisms of interprovincial virtual water flows in China

Against the backdrop of increasingly severe global water scarcity and regional supply-demand imbalances, the flow of virtual water embedded in interprovincial product trade in China, along with issues of fairness and risk, has become a critical challenge for national water resource security and regional coordinated development. However, current research has mostly focused on flow accounting and pattern description, with insufficient discussion on the coupling mechanism among "water resources—economic benefits—environmental risks" and fairness assessment. Therefore, this study, based on the 2017 China Multi-Regional Input-Output Table, constructs a comprehensive analytical framework encompassing "Flow Patterns—Equity Assessment—Risk Transmission—Value Analysis". The system explores the flow characteristics, equity status, risk transmission pathways, and value distribution mechanisms of virtual water and added value across 31 provinces in China. Research indicates that: (1) Interprovincial virtual water flows in China exhibit a macro pattern of "resources flowing westward, products flowing eastward, and value concentrating and converging". There is a significant spatial mismatch between water resources and economic benefits, with resource-exporting regions failing to obtain reasonable economic returns in tandem. (2) The overall fairness of virtual water flow is not optimistic. About one-third of China's provinces are in the "fair coordination area", with most provinces facing varying degrees of efficiency loss or fairness dilemmas. The interregional pattern presents a complex landscape: "Northeast is coordinated but with hidden risks, North China is systematically optimized, Central China is generally imbalanced, Northwest is overall inefficient, and East and South China are internally differentiated". (3) Virtual water flow is an important channel for the cross-regional transmission of water resource risks. Three types of risk transmission modes have been identified: "vulnerable-dependent", "pressure-output", and "system-robust", which exhibit an imbalanced distribution characterized by "risk concentration in the west and value flow to the east". (4) The level of regional economic development, industrial structure, and resource endowment collectively shape the patterns of virtual water flow. The eastern region achieves efficient allocation and value extraction of water resources through its advantages in the value chain, while the central and western regions face multiple pressures of "high output, low returns, and high risks" under the national division of labor and path dependence. This study provides systematic scientific basis and decision support for identifying key conflict areas in virtual water flow, optimizing the national water resources spatial allocation system, and establishing and improving cross-regional ecological compensation and risk-sharing mechanisms.