The Evaluation And Simulation Prediction Of Water Resources Carrying Capacity In Lanzhou

With the rapid development of global society and economy,the demand for water resources in various regions continues to increase.However,the phenomena of excessive development,extensive water use,serious waste and water environmental pollution in the process of water resources exploitation and utilization have caused the increasing shortage of water resources,further aggravated the contradiction between the supply and demand of water resources.In this context,it has important practical significance to carry out regional water resources carrying capacity evaluation and simulation prediction,analyze the carrying status of water resources,and find the shortcomings of the current water resources system.Based on this,this paper firstly constructed a evaluation index system of water resources carrying capacity consistent with the characteristics of Lanzhou's water resources,combined the entropy weight method and the analytic hierarchy process to determine the comprehensive index weights,constructed the TOPSIS evaluation model,and based on the historical data of2005-2019 relating to society,economy,ecological environment and water resources,carried out a static evaluation of Lanzhou's water resources carrying capacity.Secondly,through constructing a system dynamics model,dynamic simulation analysis was carried out on the four scenarios including conventional development,rapid economic development,water resource conservation and utilization,and industrial structure adjustment.Finally,policy recommendations were put forward for the evaluation and simulation results.The main conclusions are as follows:(1)From 2005 to 2019,the carrying capacity of Lanzhou's water resources and it including three sub-systems of water resources,ecological environment,and economy showed an overall upward trend,and the carrying capacity of the social subsystems represented a"V"-shaped change trend,and it started to decline in 2017.Since 2015,with the implementation of relevant plans and policies,the carrying capacity of Lanzhou's water resources and the four subsystems had been improved,while the overall level of water resources carrying capacity in Lanzhou was relatively low.(2)The system dynamics simulation results showed that in the conventional mode,the total water consumption of Lanzhou in 2035 would reach 1.794 billion m~3,the water consumption would exceed the water red line(1.62 billion m~3),and the water supply would not be able to meet the demand for use;Under the rapid development mode,water resources were consumed in large quantities,and the contradiction between water supply and demand in Lanzhou would be intensified;Under the industrial structure adjustment mode,the use of water resources was the least,and the total GDP would be second only to the rapid economic development mode among the four modes.On the basis of efficient and intensive use of water resources,it would meet the needs of sustainable and stable economic development.In the water resource conservation and utilization mode,improving water use efficiency,especially agricultural irrigation water efficiency,would hold a better water saving effect.(3)Based on the evaluation results of the water resources carrying capacity of Lanzhou and the simulating forecast analysis under the four scenarios,in view of the current situation and development trend of the water resources carrying capacity in the study area,it was proposed to implement the most stringent water resources management system,increase the supply of unconventional water sources,optimize industrial structure,improve irrigation methods,increase ecological environment construction,and strengthen water quality management,further achieved sustainable use of water resources in Lanzhou.