Comprehensive Evaluation Of Changsha Xiangjiang Integrated Reservoir Area Water Ecosystem Service Function

The water storage and sediment process of the Changsha comprehensive hub project in Xiangjiang changed the process of water and sediment in the reservoir area,and caused the corresponding changes of water ecosystem and its service function.In order to reveal the changes of reservoir water ecosystem service function and value of the hub before and after the operation,promote the effective reservoir water ecosystem service function,provide the basis for the maintenance of water ecosystem service function and regulation,In this paper,the reservoir water ecosystem service function as the research object,on the hub before and after the operation of reservoir area "analysis of variation of water and sediment-water ecosystem services--a comparison of water ecosystem service value" as the main line,using ecology,environmental economics theories and methods of project operation before and after the reservoir water ecosystem service function value evaluation.The operation of the hub cut off the continuity of the main stream of Xiangjiang,changed the original natural river into a river type reservoir,changed the process of water and sediment in the reservoir area,resulting in the change of the water ecosystem and its service function.The reservoir runoff caused by the hub operation becomes large,abundant water runoff decreases and the water level rise,decrease of sediment,sediment particle refinement and other changes,the water ecosystem service function resulting in response,appear surface area to expand,water quality is good,the amount of available water resources increased,habitat fragmentation phenomenon.The results show that:(1)the total area of water ecosystem service value increased by an average of 38 billion 718 million yuan to the hub before running after running at an average of 50 billion 794 million yuan;(2)water ecosystem atmosphere regulation,water supply,water conservancy and leisure tourism,shipping,flood storage and other functions has played a leading role in the service value and the total value of more than 95%;the hub operation,flood control,tourism and leisure function value progressively,and compared before operation was increased by 3.43 times,1.83 times,and by the damming effect,epigenetic diversity maintaining the hub operation function value average only 50 million yuan,compared with before running the hub reduction 99.17%;(3)with the reduction of pollutant in sediment particles,refine the adsorption capacity of pollutants becomes strong,reservoir water purification project operation function value is 6 million yuan,69.65% less than before the operation,show that the water quality is getting better;(4)overall,the economic function of reservoir water ecosystem environment function value and value ratio varies from 23.14:76.83 to 35.94:64.04 before the project is running after the operation,and the social and cultural function value is always fluctuation in the 9 million yuan-10 million yuan,the proportion decreases gradually with the total value of.At last,based on the evaluation results,the paper puts forward some suggestions on how to regulate and control the operation mode of the reservoir,strengthen the supervision of the water environment in the reservoir area,and establish the early warning system of reservoir water ecosystem service function.