Analysis of transboundary water flows linking physical water supply and virtual water trade through water-food-trade nexus approach

Abstract:

This study aims to analyze the interaction between physical and virtual water flows as a transboundary water management linking watershed management and food trade. Even if food-importing areas do not obtain physical water from a specific water basin, there are interactions between water basins and food-importing areas in terms of virtual water. Therefore, we quantify physical water flow from water basins to producing areas and virtual water flow embedded in food trade, respectively. Finally, we integrate physical and virtual water flows into transboundary water flows through water-food-trade nexus approach. In addition, we analyze natural and socio-economic impacts on transboundary water flows, for instance, physical water supply from water basins is strongly related to climate change in terms of water availability but virtual water is more related to the food security and trade issues. As a representative example, we analyzed interaction between water withdrawal in Hyogo prefecture and the import of virtual water in Osaka prefecture in Japan, and the results showed that the northern watershed in the Kansai region directly affected the Hyogo prefecture, which was also indirectly influenced by Osaka prefecture. The approach for transboundary water management can bring new sight of the relationship between water and food but also water basin and food consuming area in the context of transboundary management.