Ecological Compensation Standard Based On Water Quality Improvement Cost And Ecosystem Service Value In Taoxi Creek Within Upper Jinjiang Watershed

Watershed ecological compensation is one of the important methods to measure the value of water resources in the natural-human system,which is helpful to alleviate the conflict of interest in the use of water resources between different administrative regions in the upstream and downstream of the watershed.From the perspective of ecosystem services,the study of the spatiotemporal flow process of water resources in the nature-human system,establish the watershed ecological compensation model on the basis of water pollution in the basin can meet the actual needs,alleviate the contradiction of water use in watershed,and finally achieve the maximization of the interests of all parties.Therefore,a set of scientific ecological compensation model is of great significance to achieve sustainable utilization of water resources,as well as land-sea integration.This study aims at the problem that the allocation and calculation basis of ecological compensation amount in the upper of Jinjiang watershed are not clear.TaoxiHuyangxi creek within Jinjiang watershed was selected as the research area,the methods of water quality monitoring,GIS,SWAT hydrological model,ecosystem service flow were used to carry out the research on ecological compensation model.The main findings are as follows:(1)The spatiotemporal variation characteristics of water quality in Taoxi creek and its influencing factors were revealed,and the compensation amount based on water quality was quantified.Based on 16 on-site monitoring data of water quality in Taoxi creek from April 2019 to July 2020,it is found that the concentration of pollutants in Taoxi creek has significant spatial and temporal variability:the main components of nitrogen pollution in the watershed are NO3--N and NH4+-N,with the largest contribution is NO3--N,while the concentrations of NH4+-N and TP increase significantly as the river reaches the downstream.The concentrations of NO3--N were the highest in summer and the lowest in winter.The concentrations of TP and NH4+-N were the highest in winter and the lowest in summer.The analysis of the influence of land use on water quality shows that the Taoxi creek is mainly polluted by non-point sources,agricultural land and construction land are the important factors affecting river pollution,and forest land plays an obvious role in improving river water quality.According to the current local pollutant treatment cost and the water quality target level of Taoxi creek,the final calculated compensation amount based on water quality is 1.19×107 yuan.(2)The SWAT hydrological model of Jinjiang watershed was constructed,and the compensation amount based on ecosystem service flow was quantified.The runoff data of Anxi,Shanmei Reservoir and Shilong hydrological stations in the Jinjiang watershed were calibrated and verified.The three indices R2,NSE and PBIAS all met the requirements of fitting,and the simulation results of the model were good.By using ArcGIS,the Jinjiang watershed was divided into 33 sub-basins and their water yield was mapped.The results showed that the sub-basins with large water yield were concentrated in the middle reaches of the basin(No.14,23,25,17,18 sub-watershed)and Taoxi Basin(No.9,10,11 sub-watershed)The results show that the sub-basins with large water demand are concentrated in the lower reaches of the basin(No.27,28,29,31 sub-watershed)and the vicinity of Anxi County(No.13,15 sub-watershed).SWAT model was applied to simulate the spatial flow direction and spatial-temporal flow characteristics of ecosystem service flows in Jinjiang watershed,and the scope of supply and benefit areas in each sub-basin was defined.In 2013,2016 and 2019,Taoxi creek in the study area has always been the supplier of water ecosystem services in Jinjiang watershed.Finally,the compensation amount based on ecosystem service flow was calculated to range from 1.96×107 yuan to 4.72×107 yuan.(3)Considering the compensation amount of water quality and ecosystem service flow,Taoxi creek should get 33 million to 47 million yuan of economic compensation from downstream ecosystem beneficiaries annually.In view of the above calculation results,some suggestions for water resources management in Taoxi creek are put forward:To explore a more detailed ecological compensation amount,the compensation amount can be divided into township units;To broaden the sources of funds,in addition to the government’s financial transfer payment,we can also actively explore a variety of modes,such as project compensation,technical compensation,policy compensation and intellectual compensation;The Jinjiang watershed ecological compensation management group can be established to coordinate the calculation,collection,distribution,allocation and supervision of ecological compensation funds in the watershed.