Study On Water Ecological Carrying Capacity Of Weinan City Based On Multi Scenario Prediction

With the rapid development of regional economy and society,water crisis problems such as shortage of water resources and aggravation of water pollution continue to appear,the construction of water ecological civilization has become the top priority of urban sustainable development.Taking the water ecological carrying capacity as an important starting point,it is of great significance to define the maximum development scale of the city under the support of water ecology,coordinate development of water ecological system,economy and society and guide the construction of water ecological civilization for the urban.This paper takes Weinan City as the research object.Based on the analysis of the social and economic situation,water resource condition and water ecological situation of Weinan City,four kinds of urban development schemes including conventional development scheme are designed.The system dynamics method and multi-objective optimization method are used to predict and calculate the urban development scale and the maximum bearing scale under the four schemes.Through the comparative analysis between the prediction scale and the maximum bearing scale,the optimal scheme of urban development is recommended,which provides ideas for the construction of urban water ecological civilization.The main research contents and achievements are as follows:(1)The concept range of water ecological carrying capacity is defined,and the problems of water resources and water ecology in the study area are summarized.On the basis of combing the concept and connotation of water ecological carrying capacity,the scope of water ecological carrying capacity studied in this paper is defined;This paper analyzes the general situation of social economy and water ecology in the study area,calculates the regional water resource conditions and ecological water consumption,and sums up the water resource and ecological problems existing in the economic and social development of the study area in recent years from the aspects of water resource development and utilization and water environment impact(2)The SD prediction model of water ecology and economic development in Weinan City is established,and the prediction results are analyzed.Based on the data of Weinan's economic development,water supply and consumption and water environment in a certain historical period,the SD simulation prediction model of Weinan City is constructed according to the modeling steps of system dynamics.Four scenarios of conventional development,ecological priority,industrial structure adjustment and comprehensive development are set up,and the urban development scale of Weinan City under each scenario is predicted by using the model.The prediction results are analyzed from three aspects of social economic scale,water resource utilization and water ecological impact,and the evaluation index system based on DPSIR model is constructed to comprehensively evaluate each scenario scene.The results show that the water ecological comprehensive index of the comprehensive development scenario is the largest of the four scenarios,and it is rising continuously.The water ecological comprehensive evaluation index increased from 0.47 in 2019 to 0.65 in 2030.It is in a "good" level by 2030,which meets the requirements of sustainable development.In the four scenarios,it is the most favorable to solve the contradiction between supply and demand of water resources and improve the water ecological environment(3)A multi-objective calculation model of water ecological bearing capacity is established by NSGA-II algorithm,and the water ecological bearing capacity of Weinan City is measured Based on the limited carrying capacity of urban water ecology,aiming at the optimal quality of water ecological environment,the highest economic output value and the largest population scale,the multi-objective optimization model of water ecological carrying capacity is constructed under the constraints of the maximum available water supply,the proportion of water demand of ecological environment and the capacity of water environment,and based on the non dominated sequencing genetic algorithm with elite strategy(NSGA-II),four kinds of development situations are analyzed The water ecological carrying capacity of the scene is calculated,and the carrying capacity of water resources to human social economy is measured from the perspective of water and ecology.The results show that the comprehensive development scenario can bear the largest economic scale,and the GDP can bear 444.8 billion yuan by 2030(4)Evaluation and optimization of urban development plan.This paper makes a comparative analysis of the urban development prediction scale and the maximum water ecological bearing scale under different schemes.Combined with the comprehensive evaluation of the DPSIR model,the comprehensive development scene can realize the benign development of water ecology and economy and society.Compared with the water ecological carrying capacity,the comprehensive development scheme is recommended as the best plan of urban sustainable development,which has the largest development potential and space when the total water consumption,sewage discharge and other indicators do not exceed its maximum carrying capacity.Finally,based on this conclusion,some reasonable suggestions for the future sustainable development of social economy and water ecology in Weinan City are put forward.