Sustainable Evaluation Of Water Footprint In Arid Area Watershed

Water is an important environmental factor in northwest arid region of China, and it plays a decisive role in the development of social and economic and in improving the ecological environment. It is widely believed the sum of the overall consumption of water resources is the consumption of varieties of independent waters and water pollution, little attention paid to the activities of commodity type, quantity, and service in water consumption and pollution of the production chain before water footprint proposed. With the development of economy, however, water resources are facing unprecedented pressure, water shortages and pollution cases frequently staged, the environmental, ecological and social problems abound. Recent years, people have to face the embarrassing reality of the drying up of the Dang river, located in northwest district,which has been regarded as the mother river of DunHuang. According to the 20 years statistics, the water level dropped by a total of 10.77m,23% narrow of the water area, and 20% of pasture disappeared, wetlands with significant ecological benefits remaining less than half. In the year of 2011, for the sustainable development of the Dang river, the State Council approved the adoption of "DunHuang rational utilization and ecological protection of water resources integrated planning (2011-2020)," it raised the national level of attention. The traditional water resources assessment method emphasis on the comparison and analysis of the direct taking water, and it doesn’t take the dual demands of water quantity and quality into account.The proposing of the theory of the water footprint, enrich the connotation and extension of water, making it closely linked between the water and the production of human life, and it provides a guideline to solve the water problem.In this paper, on the basis of the water footprint theory, using water resources bulletin, statistical yearbook data and Cropwat software accounted the variation of blue water, green water and gray water footprint in the basin of Dang river, and made sustainable assessment on water footprint of the basin in accordance with international standards on water footprint assessment, proposed different measures to control the body’s water footprint. Finally, the paper proposed the water management systems in line with the development of the river basin.Conclusions of the study are as follows:(1) DangHe river basin water annual footprint in 2003-2013:34%(1.51 Gm3) was Green water footprint,66% (2.88 Gm3) was blue water footprint; the 70% grey water footprint from crop products, and the 30% from animal by-products, the 96% grey water footprint in Dunhuang; 70%(2.41Gm3) was crop products,30%(1.01 Gm3) was animal by-products. This suggested that the crop production consumed a lot of blue water resources, and animal by-products consumed a lot of green water resources, and the crop production polluted the river.(2) The crops blue water footprint was increasing, in 2003, it was 1.56G, in 2013, it was 2.6G,and the amount of blue water was 22.59G; the blue water footprint increased a little, in 2003, it was 0.12G, in 2013, it was 0.15G, the amount of green water footprint was 1.54G, and it less than blue water footprint. Cotton is a major part of the crop blue water and green water footprint, the crop blue water was 11.13G, and the crop green water footprint was 1.02G; in 2003, the amount of grey water footprint was 0.13 G, in 2013, it was 0.21 G, The total amount of grey water footprint was 1.77G, and it more than green water footprint.(3) Most of blue basin water resources were consumed by crops, livestocks consumed about half of the green River Basin water resources,so did crops. Cash crops,which wasted most of blue water, half the blue water footprint consumed by the cotton crops. Livestocks had a little proportion in the blue water footprint.Crops and livestocks used up half of basin green water footprint:cash crops took up 96.7%, cotton was a major part of the economic crops green water consumption,wnich reached 66.7%; Pork was the main reason for green water consumption,which took up 67.2% in the livestocks’ green water footprint.(4) Blue water footprint of animal products increased a little, it began in 2003, it was 0.11G, and ended in 2013, it was 0.13G, the amount of blue water was 0.71G, the blue water footprint of mutton beyonded the pork; Green water footprint, it began in 2003, it was 1.4G, and ended in 2013, it was 1.2G, and greater than the blue water footprint, the amount of green water was 11.9G, the blue water footprint of pork beyonded 60%; the grey water footprint changed small, the amount was 1.77G。(5) We evaluated the water footprint of DangHe basin, five months of blue water footprint beyonded blue water resources, was unsustainable, the blue water changed was bigger during the year, the maximum was 135%, the minimum was 10%; the blue water footprint less than blue water resources, and achieved 100%, the blue water footprint was shortaged, seven months of green water was shortaged more than 81.2%; the DangHe basin was less polluted; the agriculture water footprint of Dunhuang was 1.2 times of the total actual agricultural irrigation water, too much water footprint bringed many environmental problems, planting structure and water resources were related closely.(6) On the basis of sustainable water footprint, we formulated the measures to control water footprint, For example, we put forward water-saving transformation and established "Independent management+ Water users association+ The ministry door".