| The three ports of Jingnan are an important link between the Dongting Lake River and the Yangtze River,as well as an important agricultural supply area for China.With the acceleration of urbanization,the problem of water resources is becoming more and more serious,and it is urgent to promote the sustainable use of water resources in the Sankou region of Jingnan.By using the Moving-average model test,Pearson Test,Mann-Kendall test and Spearman rank correlation test,this paper analyzes the evolution trend of precipitation,runoff and other water cycle factors in Sankou area of Jingnan,and considers the response of ecological effects to water resources system,the typical correlation method is used to verify the relationship between water resources system and ecosystem,and the coupling system model of water resourceseconomy-eco-environment is constructed by System dynamics,and the simulation of sustainable utilization of water resources in Sankou area of Jingnan is carried out,based on the constraints of "three red lines",this paper forecasts the structure of water resources under various scenarios,recommends the optimal decision-making for sustainable utilization of water resources in Sankou area of Jingnan,and provides reference and suggestions for water resources management departments.The main conclusions are as follows:(1)From 1959 to 2017,the annual precipitation in the San Kou area of Jingnan changed sharply,and the distribution of the incoming water was uneven.The annual precipitation under different frequencies of abundance(20%),plateau(50%),drought(75%)and extreme drought(95%)was 1453 mm,1219 mm,1080 mm and 946 mm,respectively,from 1995 to 2018,the value of ecosystem services decreased from 658.87×108 yuan to 594.65×108 yuan.The highest value Coefficient of water ecosystem service was 62.31×104 yuan·hm-2·a-1,and the change of water area contributed significantly to its value.The correlation between Water Resources System and eco-environment system was strong,and the typical correlation Coefficient was 0.818.(2)With the help of the DPSIR model to identify the system boundary,a coupling System dynamics model of water resources,economy and ecological environment in Sankou area of Jingnan was constructed by using Vensim software,the dynamic equations of 58 systems are established.According to the validity test,the deviation is less than 5%,which shows that the System dynamics can simulate the water resources system in Sankou area of Jingnan well,combine the sensitive parameters and multi-objective factor analysis,and take the "three red lines" as the constraint,the 16 control parameters of four scenarios were determined to provide decision-making basis for realizing sustainable utilization of water resources.(3)Under the status quo continuation plan,it is predicted that the contradiction between supply and demand of water resources in the San Kou area of Jingnan will continue to rise and the ecological and environmental problems will become more and more serious.In 2035,the total water demand reached 1.1428×108 Cubic metre,and the ratio of domestic,production and ecological water demand was 8.2:90.5:1.3.The gap between supply and demand increased to 0.53×108 Cubic metre,the ecological effect caused a 13.6 percentage point decrease in GDP,and the water pollution in the San Kou area of Jingnan caused a 0.062×104 decrease in the annual population growth.under the Economic Priority Development Programme,the contradiction between the supply and demand of water resources is even more pronounced,with a supply and demand gap of 0.714×108 Cubic metre in 2035,a decrease in agricultural land and an increase in the construction area.Under the water-saving priority development programme,the impetus for regional economic development is insufficient,in 2035 the GDP was lower at 2020.11×108yuan.(4)The coordinated development plan is recommended as the best plan for the sustainable utilization of water resources in the Sankou region of Jingnan.According to the regulation of parameters,the rational development and utilization of water resources,the improvement of water use efficiency,the increase of investment in water conservancy,the optimization of land use,and the acceleration of industrial transformation,the sustainable use of water resources,with the largest carrying capacity and the highest gross domestic product,is expected to carry a total population of more than 210.236×104 by 2035,and the gross domestic product of the Jingnan region will reach 2,677.89 × 108 yuan,at this time,the three industrial structure adjustment is 15.24:40.12:44.64,and the total water demand is at least 11.044×108 Cubic metre.The value of ecosystem services amounted to 622.42×108 yuan.The water environmental status and ecological health status were better than the other three schemes. |
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