Assessment Of The Regional Transfer Of Virtual Water And Optimization Of Trade Structure

In the 2lst century, water shortage is one of the most important socio-economic and ecological environment problems, which will restrict the development of economic and the sustainable development of ecological environment. The concept of virtual water provides a new idea to solve the problem of water shortage and water security. In this paper, from the perspective of countries and cities, we analysis virtual water flows in various industries and established an optimal allocation model of import and export based on the implicit resources and environmental factors.From the perspective of countries, we used Input-Output method to calculate the water coefficient of various industries in China and the virtual water flows in trade. The results showed that industries with larger direct water input coefficient, which can be limited in water-poor areas or encourage the development of it in water-rich region. Industries with larger indirect water input coefficients, if they are the leading industry in water-poor area, we need to increase the import proportion of intermediate inputs, in order to not affect the water resources of this region severely. Besides, China exported a large number of virtual water abroad. China's total net export of virtual water was 18.15 billion m3 in 2002, 36.32 billion m3 in 2007. In the import and export trade with some countries, China exported (net) a large number of virtual water to the United States, Japan and the EU. When trading with these countries, the industry with high total water use coefficient always in a state of net exports.From the perspective of cities, we used Input-Output method to calculate the water coefficient of various industries in Tianjin and the virtual water flows in Tianjin. We found that Tianjin changed the state of virtual water trade and became a net transferred region from 2002 to 2007. This change was mainly due to the adjustment of the high water consumption industries from net exported to net imported, such as agriculture, chemical industry, textile and garment industry, etc. Second, they increased exports of high-yield and low water consumption industries, such as electrical machinery and equipment manufacturing industry, transportation equipment manufacturing industry, electronic instruments industry and other industries. Based on the above analysis, we established an optimal allocation model of import and export based on the implicit resources and environmental factors. After setting three programs and solving them. We found that, in the three programs, whether the goal is the largest GDP or the lowest COD, CO2 emissions, the adjustment of some industries are the same and the adjustment of other industries varies with the different objectives.