| The water diversion project of Yin Ha Ji Dang is a water conservancy project from Da Ha Er Teng River to Danghe reservoir.As early as 1958,some experts and scholars pointed out that the water diversion project of Yin Ha Ji Dang is the ultimate means to fundamentally solve the problem of water shortage in Dun Huang city.However,as the water transfer project brings huge economic,social and ecological benefits,it also changes the natural distribution of water resources and breaks the original water cycle characteristics and ecological balance.If the planning is not appropriate,it will cause serious damage to the ecological environment.Therefore,the project has not been carried out.In 2004,at the second session of the 10th National People's Congress,the Ministry of water resources responded that the project involves ecologically sensitive areas,and that it should be carefully planned and considered before carrying out the project.The water transfer area and water transfer area of the water diversion project of Yin Ha Ji Dang both arid areas,and the Su Gan Hu basin in the water transfer area is one of the most important protected wetlands in China.The purpose of this paper is to determine the most appropriate water transfer scheme for the ecological sensitive areas(large and small Su Gan Lake Wetland and Nu Hu Tu shallow groundwater buried area)in different water transfer schemes.Based on the field survey and data collection of the Su Gan Hu basin,this paper determines the research scope,analyzes the boundary conditions,establishes the hydrogeological mathematical model and conceptual model of the area,checks the initial seepage field of the Su Gan Hu basin,and according to the research of experts and scholars and the size of water demand,establishes four different water transfer methods,i.e.80,100,120 and 150 million m~3/a Case,and 5,10,20 and 50 years of water transfer cycle;based on the initial seepage field,respectively simulated the impact of water transfer on groundwater ecology in the shallow groundwater area of nuhutu,the ecologically sensitive area,and the wetland of large and small Su Gan Lake under different water transfer schemes and water transfer cycles,and visually displayed and analyzed the predicted results in the form of charts and pictures.According to the comparison and analysis of simulation results,under the principle of ensuring sufficient water transfer as much as possible,reducing the falling range of water level and avoiding excessive reduction of lake surface,the water transfer scheme of 100million m~3/a is the most appropriate.In the process of prediction,the water level of Nu Hu Tu shallow groundwater area and large and small Sugan Lake Wetland in the ecologically sensitive area decreased slowly in the west side and rapidly in the east side;at the same time,the water level of Nu Hu Tu shallow groundwater area decreased in different water transfer schemes and water transfer periods,among which,the water level decreased at the end of 50years under the water transfer schemes of 80,100,120 and 150 million m~3/a The drop of water level is 0.16-28.73,0.18-32.01,0.25-43.85 and 0.29-48.08m respectively;the reduction rate of lake surface under different water transfer schemes and water transfer periods is 4.76%,4.97%,6.84%and 7.33%at the end of 50 years under water transfer schemes of 80,100,120 and 150 million m~3/a respectively.Finally,it provides a theoretical basis and scientific support for the impact of the water diversion project of the Harbin Economic party on the groundwater ecosystem in the region and the determination of the water diversion scheme. |
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