Evaluation And Analysis Of Water Resources Vulnerability In Chongqing Municipality

There are many problems in the development and utilization of water resources in Chongqing,such as the contradiction between supply and demand,low utilization efficiency,serious droughts and floods,and unreasonable water structure.To study the fragility of water resources in Chongqing,water resources recoverability and sustainability are included in the evaluation system based on the commonly used water resources assessment system,and water resource vulnerability is defined as the fragile state of water resources under natural pressure,human disturbance pressure,recoverability and sustainability.On this basis,15 evaluation indicators are selected to elaborate the evaluation indicators,and the water resources vulnerability evaluation index system is constructed from four aspects: natural vulnerability,human vulnerability,recoverable vulnerability and sustainable vulnerability.Comparing the weights and evaluation results of the two methods of analytic hierarchy process and principal component analysis,the advantages and disadvantages of the two methods are discussed.To avoid the defects of subjective and objective weighting,the AHP-PCA weight calculation model is constructed and each evaluate the weight of indicators,use the comprehensive water resources model to evaluate the water vulnerability of Chongqing in 2002,2007,2012 and 2017.On this basis,the paper analyzes the spatial distribution characteristics and its changing characteristics of water resources vulnerability in Chongqing,and evaluates the potential risk of vulnerability,pointing out the location of the water environment in Chongqing and the need to be treated;then it will affect the water.The factors of resource vulnerability are classified according to whether they are controllable,and the internal mechanism of the water resource vulnerability system is analyzed,and how to manage the vulnerability from within the system is proposed.The main research results are as follows:(1)Define the vulnerability of water resources,and build a vulnerability assessment model through socio-economic data,remote sensing image data,water resources statistics,etc.,and integrate water resources recovery and sustainable use of water resources into the evaluation model based on traditional research.(2)The analytic hierarchy process and principal component analysis are used to evaluate the vulnerability of water resources.It is found that the results of water resources vulnerability assessment based on analytic hierarchy process focus on the internal structure of the indicator system,and the amount of information carried by the indicator itself is less;The results of water resource vulnerability assessment based on principal component analysis focus on the internal structure of the data and the degree of response to the vulnerability content is insufficient.In order to better reflect the focus of these two analyses,the AHP-PCA model is constructed to evaluate the vulnerability of water resources.The results can better integrate subjective and objective factors and obtain more complete evaluation results.(3)Research on the spatial distribution characteristics of water resources vulnerability in Chongqing City found that the regions with high water resources vulnerability in Chongqing are mainly distributed in the main city and surrounding areas;the lower areas are mainly distributed in the non-karst areas of northeastern Yunnan and southeastern Guizhou.Most of the area.Among them,the high natural vulnerability of water resources is mainly distributed in the middle and mountainous areas of northeastern Yunnan and the low and middle mountainous areas of southeastern Yunnan.The low values are mainly distributed in the parallel ridge valley area of central Guizhou.The overall distribution law of human resource vulnerability in space is higher in the main city and surrounding areas,lower in southeastern Yunnan and lowest in northeastern Yunnan.The recoverable vulnerability of water resources is higher in northeastern Yunnan and southeastern Yunnan,and lower in the parallel Linggu area in central Yunnan.The high value of water resources sustainable vulnerability is mainly distributed in the northeast-southwest line,and the low value area is distributed in most parts of southeastern Yunnan and a small part of northeastern Yunnan.In the distribution of different vulnerability levels,the first-level vulnerability is mainly distributed in the northeastern part of Yunnan;the second-level vulnerability is widely distributed and distributed throughout the city;the third-level vulnerability is mainly distributed in the southwest;the fourth-level vulnerability and the fifth-level vulnerability Mainly concentrated in the main city.(4)Research on the change of water resources vulnerability in Chongqing and the potential risk assessment of vulnerability found that between 2002 and 2017,the vulnerability of water resources in Chongqing decreased year by year,the natural vulnerability increased year by year,and the overall vulnerability of human beings increased slightly.,the vulnerability can be reduced year by year,and the fragility of sustainable fragility changes.Chongqing's water resources fragility is significantly improved in the northeastern and western Yunnan regions,with significant deterioration in the southern part of Chongqing.The areas with high potential risk of water resources vulnerability in Chongqing are mainly in Yunyang and the southwestern part of the main city.The medium area is mainly distributed near the main urban area,the southeastern margin of the southeast,and the vicinity of Yunyang.The water resources in the main city and surrounding areas are highly vulnerable and have a tendency to deteriorate year by year,so the potential risk of water resource vulnerability is large.Low-risk areas are mainly distributed in the parallel ridge valley area,southeastern Yunnan,and most of northeastern Yunnan.The risk-free areas are mainly distributed in the northeastern part of Yunnan.(5)According to the potential risk of water resources vulnerability in Chongqing and the internal mechanism of water resources vulnerability system,the countermeasures for water resources vulnerability in Chongqing are proposed.In terms of potential risks of water resources vulnerability,risk-free areas are mainly based on prevention,and low-risk areas and medium-risk areas should adopt corresponding measures according to specific vulnerability models.High-risk areas should pay sufficient attention and focus on governance.In terms of the internal mechanism of water resources vulnerability system,direct controllable factors,that is,water resources governance investment can be directly adjusted;indirect controllable factors can reduce their possible harm by improving the surrounding environment;irreversible factors are regulated by other factors To reduce this type of negative impact.