Study On Long-term Mechanism Of Water Ecological Security Taihu Lake Basin

Taihu Lake Basin is an important research object of basin governance in China.Since the outbreak of cyanobacteria in Taihu Lake in 2007,the basin has carried out a decade long battle to control the Pacific Ocean,and the water quality of the basin has been significantly improved in the short term.However,cyanobacteria blooms still occur from time to time in Taihu Lake,the pollutant load remains high,and the long-term effectiveness of water quality improvement is insufficient.Based on the current situation of water ecology in Taihu Lake Basin,this study analyzes the problems of water ecological governance in Taihu Lake Basin for the purpose of maintaining the long-term effectiveness of water quality improvement and water ecological improvement in Taihu Lake Basin.According to the definition of water ecological function zoning in Taihu Lake Basin of Jiangsu Province in 2016,this study puts forward the basic framework of long-term mechanism of water ecological security in Taihu Lake Basin in Jiangsu Province.The framework mainly includes the conventional management system for the whole basin and the ecological control mechanism based on the ecological engineering measures in each region.The main research contents and conclusions of this paper are as follows:1.Investigation on the current situation of water ecology in the basin.According to the water ecological environment function zoning of Taihu Lake Basin in Jiangsu Province(Trial Implementation)in 2016,the ecological investigation is carried out for each zoning(Taihu Lake body,water purification area,water source conservation area,water environment maintenance area and important habitat maintenance area)from three aspects of habitat pressure,ecological state and service function to preliminarily understand the ecological status of each zoning.It is found that the high concentration of nitrogen and phosphorus,the low diversity index of benthos and the low proportion of wetland area are the common problems of aquatic ecology in the basin.2.Water ecological security assessment based on zoning.Using the P-S-S(pressure state response)model,taking habitat pressure,ecological state and service function as the factor layer,this paper constructs a water ecological security evaluation index system including three categories and 27 indicators.Considering the differences in the positioning of the leading functions of each division in the basin,different evaluation index systems are proposed for different divisions;Then the weight of each index is determined by the combination weighting method,and the ecological security index of each partition is calculated.The score shows that the ecological security index of Taihu Lake and water environment maintenance area is low,63.60 and 67.69 respectively,indicating that the ecological leading function of Taihu Lake and water environment maintenance area is weak compared with other districts.3.Analysis of ecological governance in Taihu Lake Basin.Based on the literature reading and on-site ecological investigation results,this paper analyzes the water ecological governance of Taihu Lake Basin from two aspects: important ecological problems(phenomena),conventional management system and ecological system(system operation).The results show that there are problems in the supervision and assessment system,institutional function setting,ecological monitoring system and supervision and management system.4.Establishment of long-term mechanism framework for water ecological security in Taihu Lake Basin.This paper mainly establishes the basic framework of the long-term mechanism of water ecological security from two aspects: one is the conventional management system,and the other is based on the maintenance and control mechanism of engineering measures in each division,and puts forward some suggestions on the establishment of the long-term mechanism of water ecological security in the basin.