Environmental And Economic Assessment Research On The Improvement Of Urban Inland River Water Environment Quality

The Action Plan of Water Pollution Prevention and Control promulgated by the State Council has made the remediation of urban black and odorous water bodies an important part of the work of local people's governments at all levels to improve the urban human settlement environment.In the "13th Five-Year Plan" of Jianye District,Nanjing City,it is also clearly proposed that we should further strengthen the governance of the ecological environment and comprehensively improve the quality of urban water environment.However,the environmental value of urban river environmental quality after improvement cannot be realized through market transactions and can not be measured by market price.Therefore,the contingent valuation method(CVM)is required to conduct scientific and reasonable monetary valuation of urban river environment.In this paper,the water environment quality in Jianye District,Nanjing City during the "13th Five-Year Plan" period was analyzed respectively by single factor evaluation method and comprehensive pollution index method.Based on CVM,the willingness to pay(WTP)and willingness to accept(WTA)of residents in Jianye District of Nanjing are taken as the research object,and the correlation analysis of residents' willingness to pay is carried out to get the environmental benefits of improving water environment quality.Implement the sustainable development of urban water bodies and provide impetus for the continuous improvement of environmental quality.The main research results are as follows:(1)The overall water quality in Jianye District,Nanjing City,was significantly improved through the regulation in the 13 th Five-Year Plan period.Through the single factor evaluation method,it is found that the number of poor ? water bodies is reduced,and ammonia nitrogen and total phosphorus in the urban water bodies of Jianye District are excessive pollutants,and they are also the limiting factors of the water quality of inland rivers in Jianye District.The comprehensive pollution index of nine selected river courses and lakes decreased throughout the year during the 13 th Five-Year Plan period.However,the improvement results of water environment quality in the study area are prone to fluctuation,and the comprehensive treatment of water environment still needs to be strengthened.(2)Urban river environment has significant economic value,and with the improvement of water environment quality,willingness to pay is also on the rise.By asking the interviewees to choose the proportion of payment,it is estimated that the willingness to pay per capita was 197 yuan in 2015 when the water bodies were not completely improved,thus the economic value of urban inner rivers in Jianye District was 90 million yuan.The average WTP and WTA of respondents in 2019 are 289 yuan and 454 yuan respectively.Therefore,the economic value of urban inland rivers in Jianye District in 2019 can be calculated as 146 million yuan and 230 million yuan respectively by WTP under the dual-boundary two-part guidance technology and WTA under the payment card guidance technology.By comparing the average WTP of interviewees in 2015 and 2019,it can be found that the improvement of water environment quality improves the residents' willingness to pay,and then enhances the economic value of urban inland rivers in Jianye District,indicating that the improvement of water environment quality greatly improves the economic value of urban inland rivers.(3)In the same period,there was a large gap between the willingness to pay for the improvement of water environmental quality online and offline.Such a gap,in addition to the factors of guidance methods,is also due to the difference in personal experience of the respondents and the information deviation caused by their residential address.The respondents in the online survey lack intuitive feelings about the improvement of water quality in Jianye District.Moreover,the online survey population has no direct interest relationship with the improvement of river courses in Jianye District.(4)By analyzing the correlation between the personal information of the CVM survey samples and the willingness to pay and the willingness to receive compensation,the analysis results show that: At the level of 1%,education level,family annual income,water satisfaction and information openness and transparency have a significant positive impact on residents' willingness to pay,while at the level of 5%,occupation and age have a significant negative impact,while gender has no significant impact.At the level of 1%,education level,family annual income and information openness and transparency have a significant positive impact on residents' willingness to accept,while at the level of 1%,occupation has a significant negative impact,while gender,age and water body satisfaction have no significant impact.