Study On The Multidimensional Critical Control Technology Of Water Resources In The Manas River Basin

The Manas River Basin is located in the inland arid region of northwestern Xinjiang,far from the sea,with a dry climate,low precipitation,and strong evaporation.The basin is dominated by agricultural production.The long-term water use structure has significantly reduced the amount of surface water that flows into the downstream,tail lakes have gradually disappeared,and the ecological environment has been severely damaged.To ensure the sustainable use of ecological water demand and water resources,and to further enrich the research system for the sustainable utilization of water resources.This paper starts with the analysis of the water use structure and land use changes in the Manas River Basin and analyzes the supply and demand balance of basin water resources by using system dynamics.Based on this,a multidimensional critical regulation model is constructed to optimize the water resources structure of the river basin.The main conclusions of the study are as follows:(1)The Manas River Basin is dominated by agricultural production,and the proportion of water used in agriculture is basically maintained about 95%,the industrial water use is slightly higher than 3%,and the domestic water and the ecological water are about 1%.Unreasonable water use structure has caused severe damage to the ecological environment.From the perspective of the added value of unilateral water,the added value of industrial water is much higher than that of agriculture,and the proportion of industrial water should be continuously increased.(2)Before and after the promotion of water-saving technologies,the area of arable land increased from3320.86km~2 in 1976 to 7437.52km~2 in 2015,making agricultural water use maintained at over 90%.In order to further reduce the proportion of water used in agriculture,in addition to further promoting the application of drip irrigation technology under the membrane,measures should be taken to return farmland to forests and grasslands and reduce the area of cultivated land.Industrial land,transportation land and residential land all showed varying degrees of growth.The increasing rate of residential land reached123.5%,while industrial water and domestic water increased by only about 2%,and the growth rate was relatively slow.Although the ecological water consumption is always maintained at about 1%,the amount of available water is still decreasing,and the ecological environment is still not optimistic.(3)System dynamic is used to analyze the supply and demand of water resources,taking into account factors such as the demand for water resources,the supply of water resources(including surface water availability,groundwater exploitation and spring water),industrial and domestic sewage utilization,and ecological water demand within and outside the river channel.By increasing the sewage treatment rate to0.9,the planting area will be reduced by 24.47%,the unit water consumption quota for industrial output will be reduced by 42.9%,the water quota per unit area will be reduced by 11%,and the unit construction and tertiary industry water quota will be reduced by 50.The measures will reduce the water supply and demand difference to-1.23×10~8m~3 in 2020,and will reduce it to-1.98×10~8m~3 in 2030.(4)Through the comparison of the five schemes,it can be concluded that the multi dimensional critical control of water resources in 2020 adopts the scheme four,that is,the measures to strengthen the water saving and the sewage resource of the industry and agriculture can reduce the industrial water demand by0.24×10~8m~3,the agricultural water demand by 1.79×10~8m~3,and the total water requirement by 2.04×10~8m~3.By adopting the fourth scheme of multidimensional critical water resources control in 2030,the industrial water demand can be reduced by 0.75×10~8m~3 through regulation,the agricultural water demand can be reduced by 0.54×10~8m~3,and the total water demand can be reduced by 1.28×10~8m~3.When the water supply is 0.56×10~8m~3 in the Manas River Basin,the industrial and agricultural water supply is 10.85×10~8m~3,and the ecological water supply is 1.316×10~8m~3,the entropy of the water resources system will be the minimum in 2020 and the optimal control results will be achieved.When the water supply is 0.79×10~8m~3 in the Manas River Basin,the industrial and agricultural water supply is 12.07×10~8m~3,and the ecological water supply is 1.316×10~8m~3,the entropy of the water resources system will be the minimum in 2030 and the optimal control results will be achieved.The water shortages decreased by 3.54×10~8m~3 and 3.76×10~8m~3 in2020 and 2030,respectively,indicating that the water resources system was developing in an orderly and coordinated manner.