EValuation And Optimization Of Water Resources Carrying Capacity In Yunnan Central Urban Agglomeration

With the rapid development of economy and society,the problems such as the increase of population,lack of resources,ecological crisis and environmental pollution are increasing day by day,and the coordination between resource environment and regional socio-economy is paid more and more attention?As the core area of the main functional area planning and land planning of the strategic level and macro scale,the urban agglomeration has become a particularly prominent area of resource and environmental problems.Therefore,the research on carrying capacity of urban agglomeration needs to be strengthened.This paper is based on Yunnan Central Urban Agglomeration,which is located in the mountains and mountainous areas and is affected by karst rocky desertification.The water resources are regarded as a special factor of resource-social economy and ecologicalenvironment complex giant system.Sustainable development theory,eco-economic theory,urban agglomeration theory and geographical division of labor theory are the theoretical basis.Based on the statistical data of 2014,the water footprint method and formula were used to calculate the total water footprint,per capita water footprint,water resource scarcityand water resources pressure index.This paper evaluates the water resources utilizationsituation of the state and its county in Yunnan Central Urban Agglomeration in 2014.Then,based on the 2014 years,the water resources carrying capacity model of the Yunnan Central Urban Agglomeration was constructed by the system dynamics method.Under the six types including sustainable development,economic development,resource-saving,environment-friendly,government planning and coordinated development,the paper analyzes the trend of water resources carrying capacity in Yunnan Central Urban Agglomeration of 2015-2020,analyzes the main socioeconomic factors influencing the water resources carrying capacity of the Yunnan Central Urban Agglomeration and seeks to improve the optimal scheme of water resources carrying capacity.This paper explores the water resources carrying capacity of the plateau mountain and karst rocky desertification areas under the condition of water shortage,and controls the regional water resources carrying capacity based on the planning and construction of the Yunnan Central Urban Agglomeration,so as to promote the sustainable use of water resources and the coordination development of the local socio-economy.The conclusions and innovations of this study are as follows:(1)From the total water footprint,the total water footprint of the Yunnan Central Urban Agglomeration in 2014 is 41.791 billion m3,and the per capita water footprint is 2359.241 m3/person.The degree of water shortage is as high as 1.640,the water resources pressure index is 0.926,the water shortage is serious and the water resources are unsustainable.From the spatial distribution of the city,The degree of water shortage and the water resources pressure index in Kunming are the highest,the water shortage in Kunming is the most serious,followed by Chuxiong,Qujing,and finally Yuxi,the degree of water shortage in four states are more than 1,their water supply are seriously inadequate.In the per capita water footprint,the per capita water footprint of Qujing is the highest,followed by Chuxiong,Yuxi and finally Kunming.From the spatial distribution of the county,there are 39 counties in the 42 cities of the Yunnan Central Urban Agglomeration,whose degree of water shortage are greater than 1,accounting for 92.86%of the total.The shortage of water resources is grim.(2)The simulation results of six schemes were carried out by using the system dynamics method shows that no matter how the value of the control variable of each scheme changes,the gray water footprint and the agricultural water are the two parts of the total water consumption of the Yunnan Central Urban Agglomeration.So,it is necessary to improve the efficiency of agricultural water use,to strengthen sewage treatment and pollutant reduction,to strengthen the recycling of sewage.The comparison of six schemes shows that,regardless of the sustainable development,economic development,resource-saving,environment-friendly,government planning and other models,a single development model can only ease some or more water pressure,only to take the coordinated development type of urban can really achieve a balanced water supply and demand.At the same time,it is further verified that the development model set up in the planning(2009-2030)of the Central Yunnan Urban Agglomeration has led to a decline in water resources capacity and not been able to ensure the coordination development of the local socio-economy due to the pursuit of urban scale,economic level and urbanization.(3)From the simulation of decision variables,the total population,urban population and urban COD reduction are the most significant factors affecting the balance between supply and demand,namely population growth rate,urbanization rate and urban COD reduction have the greatest impact on urban water demand.The population determines the size of the city's development,the needs and structure of production and consumption,thus affecting the total water demand,while increasing the COD reduction in urban areas is the most effective way to reduce the gray water footprint.In addition,the agricultural area and its production,industrial water consumption,tertiary industry water consumption are also major factors.Therefore,it is only through the appropriate slowdown in population growth rate,the pace of urbanization,control the size of the city population,reasonable adjustment of production and living structure,while strengthening the treatment of urban water pollutants namely water environment management,can effectively solve the problem of water shortages,and achieve the sustainable development and utilization of water resourcesin urban areas.But also shows that the blind pursuit of urban scale and urbanization process is not desirable,because it will reduce people's urban quality of life and urbanization quality.(4)The innovation of this research are to calculate the total water footprint from the perspective of agricultural consumption and increase the gray water footprint of the production products,and make the calculation result more in line with the present situation.Based on this,a reasonable and comprehensive model of water resources carrying capacity of Yunnan Central Urban Agglomeration is established.At the same time,through the system simulation and prediction to verify the rationality of the planning plan published by the government,so as to provide the basis and reference for the next step in government decision-making.