Multi-Level Characteristics of Consumption-Driven Virtual Water Flows: Sustainability Insights from the Pearl River Delta Urban Agglomeration

Urban agglomerations rely on both direct physical water intake and substantial virtual water embedded in cross-regional traded commodities and services to meet water demand. It is important to analyze the complex virtual water flows in urban agglomerations to advance sustainable water utilization and coordinated regional sustainable development. In this study, we constructed a multi-scale hierarchical analysis framework covering industrial sectors, internal cities and external hinterland regions by coupling multi-regional input–output (MRIO), ecological network analysis (ENA), and structural decomposition analysis (SDA). The framework was adopted to quantify consumption-driven virtual water flows across the Pearl River Delta (PRD) urban agglomeration in 2012, 2017 and 2022. Furthermore, we quantified the economic value of virtual water flows by considering water rights trading prices, which mainly reflect the scarcity value of regional water resources, aiming to provide new perspectives for water resources compensation and sustainable water management decision making. The results showed that the virtual water flows mainly satisfied food-related water requirements in the PRD. Declining water use intensity in external supply regions was the dominant factor reducing the water footprint in the PRD. The virtual water flows had greater economic value in the water-scarce northern provinces. On this basis, we put forward targeted financial subsidy recommendations for water-supplying external regions; the above economic quantification serves as the core evidence supporting this subsidy proposal. This work provides decision support for formulating sustainability-oriented water policies, balancing interregional water ecological benefits, and realizing long-term sustainable utilization of water resources.