Study On Water Resources Bearing Capacity Based On Water Footprint Theory In Midstream Of Heihe River

As a kind of special natural resources,water maintains the existence and development of all the life on the earth,which has its own threshold,but is not inexhaustible.In order to realize the sustainable development of water resources,the exploitation and utilization of water resources must be controlled within the scope of its bearing capacity.In recent years,with the rapid growth of China's population and economy,the shortage of water resources leads to the deterioration of water environment and Vegetation Land Desertification and a series of ecological environmental problems,which affects seriously the development of China's national economy.Especially the Heihe basin,which is a typical water shortage region in Northwest China,whose contradiction between water supply and demand is more obvious.Since the last century of 60 s,a large number of land was reclaimed in the middle reaches of Heihe River,which consumed a great deal of water which should be used in the ecological.It caused that the downstream water gradually reduced,and resulted into the drying up of rivers and lakes downstream areas,natural vegetation degradation,ecological and environmental problems such as sandstorm.Ejina region has become the main source of sand dust storms in China.Therefore,how to balance the relationship between the shortage of water resources and social economic development and ecological environment is the key to solve the problems of inter province water in Heihe basin.In view of the 70 percents of Heihe River water is exploited by the middle reaches basin area of the main river,Ganzhou District,Linze County and Gaotai County are treated as the study area.The study area is located in the middle part of Hexi Corridor,which is abundant in light resources,but few in precipitation,and its crops should be irrigated.Based on the status of water resources and the basic characteristics in the middle reaches of Heihe River,combining with the water footprint theory,this article constructs the evaluation index system based on the water footprint theory of the water resources bearing capacity to the middle reaches of Heihe River by reading a lot of domestic and foreign paper which related to the water resources bearing capacity evaluation.First,this paper has calculated the water footprint value of the study area from 2005 to 2014 by the component method and then predicted the water footprint in the year of 2020 and 2030 by the grey predicting GM(1.1)model;On the foundation of the econometric model,combining with the actual situation of social economic development in the middle reaches of Heihe River,the paper has constructed a social and economic development model in the middle reaches of Heihe River to the index of social economic development of the study area in 2020 and 2030;Finally,the evaluation results of water resources bearing capacity in the study area can be obtained by combining the evaluation index of water resources system and the evaluation index of social,economic and ecological environment.The results indicate that the water footprint of agricultural occupies a large amount of water footprint in the middle reaches of Heihe River;the water resources bearing capacity will be overloaded in the year of 2020 and 2030;there is a big gap between the supplied water resources and the economic forecast index predicted by the economic model.Therefore,in view of the weak water resources bearing capacity in the middle reaches of Heihe River,the paper puts forward the first way to save agricultural water that compress irrigation area and the water consumption of agricultural irrigation.The second way proposed by the paper is adjusting the industrial structure and focusing on the development of the third industry of low water consumption,high capacity such as tourist industry.The last way is improving the legal management system and the public awareness of water conservation on base of the existing water price formation mechanism.