Evaluation Of Ecosystem Service Value Of Urban Water System Comprehensive Regulation Project

In recent years,the state attaches great importance to the improvement of urban ecological water systems,and carried out a series of ecological water projects,including the construction of water ecological civilization and the comprehensive management of water systems.The implementation of these engineering projects has played an important role in improving the urban water system environment,but there is no scientific calculation method and standard for its specific comprehensive benefit and service value.In order to further measure the actual benefits brought by these projects,it is urgent to carry out ecosystem service value assessment of urban water system based on the ecosystem service value theory.This study will provide reference for the scientific identification of the comprehensive benefits of water environmental governance,water ecological civilization construction and water ecological restoration projects,and provide a scientific theoretical basis for regional social and economic development and environmental protection.Based on the domestic and foreign relevant analysis and research of ecosystem service value theory,taking urban water system as the research object.Urban water system ecosystem is divided into four functions: supply,regulation,support and society,the evaluation index system and evaluation model of ecosystem service value of urban water system comprehensive treatment engineering were constructed.Through Arc GIS for rapid modeling of SWMM model,establish the simulation model of waterlogging and water quality in the central city of Runan County,and use the radial flow model parameter calibration method based on the runoff coefficient to parameter calibration and verification.The model has good accuracy and reliability of urban waterlogging and water quality simulation model,the test effect of water system comprehensive regulation project,then the quantitative evaluation is made for flood storage and water purification in the index system.After the implementation of the water system comprehensive regulation project,the central urban area of Runan County meets the requirements of urban flood control and drainage under the design rainstorm of 1h and 6h in the return periods of 3,5,10,20 and 50 years.Under the conditions of 1h rainfall during the return period of 3,10 and 50 years,the concentration of pollutants decreased significantly,and the self-purification capacity of river channels increased significantly.Through the questionnaire survey on the water system environment in Runan county,the social function was evaluated scientifically.Based on the evaluation of the water system ecosystem service value in the central urban area of Runan County in 2016 and 2019,the water system ecosystem service value in the central urban area of Runan County was 632.5926 million yuan in 2016 and96.48577 million yuan in 2019.The water system ecosystem service value in the central urban area of Runan County has been significantly improved after the implementation of the project,among which,the social value accounts for more than half,which indicates that the water system ecosystem service function in the central urban area of Runan County is mainly reflected in the social service function.According to the evaluation of ecosystem service function,the suggestions and measures for the sustainable improvement of the water system ecosystem service value in the central urban area of Runan County were put forward.