Overview and prospect for literatures of virtual water research

The literatures of virtual water research are reviewed. The concepts of virtual water are summarized. The research advances in the virtual water are overviewed from the following five aspects:(1) methods and calculation of the virtual water in different products; (2) virtual water trade and flow trend; (3) virtual water trade and efficiency of water resources allocation; (4) virtual water and water footprints; (5) virtual water and water security strategy. Among which the virtual water in industrial goods is the weakness, especially the methods for grey virtual water. The relationship between the virtual water flow trend and the water price is scarce in researches on water resources allocation and water security strategy. More understanding is needed for the virtual water in its role in energy saving and release diminishing projects, especially in sewage treatment projects.