A dynamic analysis of water footprint of Jinghe River basin

Water footprint in a region is defined as the volume of water needed for the production of goods and services consumed by the local people. Ecosystem services are a kind of important services, so ecological water use is one necessary component in water footprint. Water footprint is divided into green water footprint and blue water footprint but the former one is often ignored. In this paper water footprint includes blue water needed by agricultural irrigation, industrial and domestic water demand, and green water needed by crops, economic forests, livestock products, forestlands and grasslands. The study calculates the footprint of the Jinghe River basin in 1990,1995, 2000 and 2005 with quarto methods. Results of research show that water footprints reached 164.1 × 108m3, 175.69×108m3 and 178.45×108m3 respectively in 1990, 1995 and 2000 including that of ecological water use, but reached 77.68×108m3, 94.24×108m3, 92.92×108m3 and 111.36×108m3 respectively excluding that of ecological water use. Green water footprint is much more than blue water footprint: thereby, green water plays an important role in economic development and ecological construction. The dynamic change of water footprints stows that blue water use increases rapidly and that the ecological water use is occupied by economic and domestic water use. The change also shows that water use is transferred from primary industry to secondary industry. In primary industry, it is transferred from crops farming to forestry and animal agriculture. The factors impelling the change include development anticipation on economy, government policies, readjustment of the industrial structure, population growth, the raise of urbanization level, and structural change of consumption, low level of water-saving and poor ability of waste water treatment. With blue water use per unit, green water use per unit, blue water use structure and green water use structure, we analyzed the difference of the six ecological function districts of the Jinghe River basin. Future ecological construction may influence on blue water use of District V and District VI at middle and lower reaches. At last some suggestions are given for effective water resource use.