Study On Temporal And Spatial Variation Of Water Resources Carrying Capacity In Yunnan Province

Water resources are not only the natural resources for human survival,but also the basic resources for economic development and social progress.In the 21 st century,water resource has become a strategic economic resource,which is closely related to national geopolitical strategy and sustainable development of social economy.In recent years,with the changes of social development and environment such as population growth,accelerated urbanization,deterioration of water environment and global climate change,the sustainable guarantee ability of water resources has become more and more important.Yunnan Province is in the southwest border of China.Although the total amount of water resources is rich,it is unevenly distributed in time and space,and it is difficult to develop and utilize.At the same time,it is affected by water environmental pollution and unbalanced regional economic development.Therefore,the contradiction between supply and demand of water resources is prominent,and the sustainable development of social economy is facing severe water resources challenges.As an important index to measure the sustainable development of water resources system,water resources carrying capacity(WRCC)can reflect the supporting ability of water resources to the coordinated development of society,economy and ecological environment.Therefore,in the face of the basic water situation of the contradiction between supply and demand of water resources in Yunnan Province,this thesis used the comprehensive weighting TOPSIS model to study the spatial and temporal changes of WRCC in the province,and constructed the WRCC-Net evaluation model based on the deep learning method,which effectively improved the evaluation accuracy of WRCC.The research on WRCC evaluation based on deep learning has positive significance for further exploring the datadriven WRCC evaluation method.Under the background of the new era of ecological priority and green development,the study on the spatial and temporal changes of WRCC in Yunnan Province is also of great significance for coordinating the relationship between water resources system and social and economic sustainable development in the study area,and can effectively provide theoretical support and reference suggestions for the efficient utilization of water resources and the formulation of industrial development planning in the region.This thesis systematically combed the connotation and development status of WRCC,and analyzed and summarized the research methods of WRCC.Taking 16 cities in Yunnan Province as the study area,the evaluation of WRCC in Yunnan Province was carried out based on TOPSIS model.By constructing the WRCC-Net evaluation model,the deep learning method was further applied to the study of WRCC in Yunnan Province.In addition,the groundwater vulnerability,which comprehensively characterizes the groundwater antifouling ability,was taken as the influencing factor of WRCC,and the evaluation results of WRCC were further refined.Finally,based on the constructed WRCC-Net evaluation model,this thesis used scenario analysis to predict and analyze the WRCC of multi-scenario development in Yunnan Province in 2025,and puts forward countermeasures and suggestions to improve the WRCC.The main work and achievements of this study were as follows:(1)Evaluation of WRCC in Yunnan Province based on comprehensive weighting TOPSIS modelBased on the study of water resources environment,economic society,ecological environment and other water resources complex giant system in Yunnan Province,a comprehensive evaluation index system of WRCC including 21 indexes was constructed.Taking 16 cities in Yunnan Province as the study area,the analytic hierarchy process and entropy weight method were used to give the subjective and objective comprehensive weights to the evaluation indexes,and the TOPSIS evaluation model was used to evaluate the WRCC of 16 cities in Yunnan Province from 2008 to 2018.The evaluation results showed that the WRCC of Yunnan Province presents a certain temporal and spatial variation characteristic.In the time dimension,since 2008,the WRCC of other states and cities except Nujiang has shown a downward trend.In the regional dimension,the WRCC was low in most parts of central Yunnan and eastern Yunnan,while the WRCC was better in northwest Yunnan represented by Nujiang.The obstacle factor analysis of the comprehensive evaluation index was carried out by using the obstacle degree model.The results showed that the water resources per unit area,water resources development and utilization rate,per capita water resources,water supply modulus,per capita water storage,population density,per capita GDP,ecological environment water use rate were the main obstacle factors.(2)Construction and empirical study of WRCC evaluation model based on deep learningBased on the deep learning theory,a WRCC-Net evaluation model based on deep learning deep feedforward network structure was constructed,and the deep learning method was further applied to the study of WRCC.The model constructed a deep network with 23 layers.The hierarchical relationship of the model corresponded to the evaluation index system,which make the relationship between the target layer,the subsystem layer,and the index layer in the model closer,and then improved the interpretability of deep learning applied to the evaluation of WRCC.The residual structure was introduced into the model to alleviate the problem of network gradient disappearance,so that the construction of WRCC-Net model can reach a deeper level.By comparing with unsupervised evaluation method,shallow structure machine learning method and deep learning DFN model,it was proved that the model has good evaluation effect.Based on the constructed WRCC-Net evaluation model,an empirical study was conducted on the WRCC of 16 cities in Yunnan Province.The results showed that the WRCC of Yunnan Province showed a downward trend from 2008 to 2018,and the WRCC in the eastern region was lower than that in the western region.(3)Superposition analysis of groundwater vulnerability to WRCCGroundwater resource is an important part of water resources,carrying the load of water resources development and utilization,social and economic development.In view of the traditional comprehensive evaluation index system design does not explicitly involve groundwater resources and environment indicators.In this thesis,the intrinsic vulnerability of groundwater,which reflects the anti-pollution ability of groundwater resources,was taken as an important influencing factor,and the superposition analysis of WRCC was carried out.According to the difference of hydrogeological conditions in Yunnan Province,the vulnerability of shallow groundwater in Yunnan Province was evaluated by using the improved DRASTIC method and EPIK method for the types of pore water,fissure water and karst water in Yunnan Province.Using Arc GIS platform,the evaluation results of WRCC were superimposed.The results showed that under the influence of groundwater vulnerability,the grade of WRCC in the prefecture was different.In some areas with high groundwater vulnerability,the WRCC tended to weaken,the higher the groundwater vulnerability,the more obvious the weakening effect of WRCC.Taking 2018 as an example,Kunming,Qujing,Pu’er,Lincang,Honghe,Wenshan and Xishuangbanna have great changes in WRCC.The weakening of WRCC was mainly affected by the high vulnerability of karst water and fissure water.(4)Scenario prediction and countermeasures of regional WRCCUsing the scenario analysis method,by designing different scenarios to simulate the social and economic development,the WRCC was predicted and analyzed,which can explore the optimal social and economic development model to achieve green development,and provide countermeasures and suggestions for the sustainable development and utilization of water resources and regional development planning.Based on the theory of scenario analysis,this thesis designed three development modes of social and economic development in Yunnan Province in 2025: continuation,economic priority,and green development.According to the development status of each prefecture and city and the ‘14th Five-Year Plan’,the prediction indicators were designed,and the WRCC-Net evaluation model was used to predict and analyze the development and changes of WRCC in 16 prefectures and cities in Yunnan Province in 2025.The results of prediction analysis showed that the WRCC of 16 cities in Yunnan Province showed different development trends under the three development modes.For most areas of Yunnan Province,the green development model was the best,which can reverse the trend of deterioration of WRCC.Combined with the analysis of groundwater vulnerability in the study area of WRCC superposition,under the influence of groundwater vulnerability,the WRCC of green development mode was overloaded,mainly concentrated in Kunming,Qujing and Dali areas.The main reason was that the vulnerability of karst water and fissure water in some areas was high.Finally,according to the current situation evaluation and simulation prediction results of WRCC in Yunnan Province,this thesis puts forward some countermeasures and suggestions to improve WRCC in the aspects of implementing optimal allocation of water resources,promoting the construction of water-saving society,strengthening the research of industrial layout,carrying out ecological environment protection and building green development mode.