Pattern Of Groundwater Exploitation And Utilization Under Large-Scale Water Saving Irrigation And Ecology Restriction In Sangong River Basin,Xinjiang

In the arid area,poor precipitation leads to the importance of groundwater which maintain the human life,production and the ecological environment,groundwater is also one of the main sources of irrigation water.Agriculture in arid areas is dominated by irrigated agriculture,the development of agriculture production is stopped by the shortage of water resources and the rare application of water-saving irrigation technology.The utilization pattern of water resources has a series of complex changes with the development of large-scale water saving irrigation technology and the important measure to improve the ecological environment,the groundwater system is also changed.Sangong River Basin(Xinjiang),with typical arid area landscape,is selected as the study area,the change rule of water level and groundwater under different irrigation scheduling and mining scheme are analyzed and researched by HYDRUS-1D and PMWIN(Processing MODFLOW for Windows).The groundwater sustainable yield is determined under the development of irrigation scheduling and the constraint condition of groundwater critical buried depth,which is of great significance for the further development of water resources and ecological sustainable development in arid areas.With the simulation and research,we can get the following main conclusions:1)The field infiltration coefficient of conventional and water-saving irrigation are within range0.542-0.662,0.109-0.410,respectively.With the development of large-scale water saving irrigation technology in the future,the field infiltration coefficient will be reduced,and the groundwater system will also change.2)Considering the impact of large-scale water-saving irrigation and groundwater exploitation on the ecological environment,six different groundwater utilization patterns are designed for numerical simulation.The reasonable burial depth of groundwater is within range 2-6 meters in the area which below the overflow zone of Sangong River Basin,the PMWIN is used to simulate groundwater under 6 water change schemes.The results show that:The proportion of the area within reasonable burial depth of groundwater is 60%in first scheme,the proportion within reasonable burial depth in fifth and sixth scheme are 94%,97%,respectively.3)The change of groundwater resources and burial depth under 6 schemes is simulated and the results show that:When the field infiltration coefficient of irrigation water is reduced to 0.2,the groundwater sustainable yield in the area that above the overflow zone of the basin is 3200×10~4m~3/a,which is 790×10~4m~3/a in the area that below the overflow zone of the basin.At the same time,the water level in most part of the area which below the overflow zone will be within the ecological burial depth.