Research On Dynamic Evaluation Method And Application Of Regional Water Ecosystem Health Status

Water ecology is of great significance to human activities.It not only affects humans daily life,but also plays a vital role in the sustainable development of the economy.The14 th Five-year Plan of our country clearly states that water environmental protection should pay more attention to the harmony between human and water.As a complex system,the health of water ecosystem is affected by many factors.With the continuous development of economy and society,the water environment and water ecosystem have been seriously damaged.Therefore,more attention should be paid to the restoration of water ecology while managing the water environment.Evaluation of the health status of water ecosystem is a comprehensive assessment tool and technical means,which can effectively identify the actual situation of the water ecosystem,and then give corresponding governance measures.This paper studies the dynamic evaluation method of water ecosystem health status,and applies the proposed method to the evaluation of the water ecosystem health status in Shandong Peninsula Blue Economic Zone.The main research content and results are as follows.Firstly,collecting literature which is based on the connotation of water ecosystem health,the water ecosystem health evaluation method and collaborative symbiosis theory.After sorting out and analyzing the literature and combining the actual health status of domestic water ecosystems,it is found that the concept of water ecosystem health is not clear,water ecosystem health evaluation method is relatively single and neglect ecological sustainable development of water problems,etc.Therefore,this paper introduces the theory of synergetic symbiosis and gives the connotation of the health of the water ecosystem from the perspective of synergetic symbiosis theory.At the same time,it constructs a symbiosis framework of water-energy-food system,and the evaluation index system of water ecosystem health is established under the condition of sustainable economic,social and ecological development.Secondly,in view of the relatively single problem of the evaluation method of the health status of the water ecosystem,the projection pursuit（PP）evaluation method is used for evaluation.The traditional intelligent optimization algorithm to solve the optimal projection vector has problems such as easy to fall into local optimality and premature convergence.The optimal projection vector determines the authenticity and objectivity of the evaluation results.Therefore,this paper adopts the improved Sparrow Search Algorithm（Improved Iterative Sparrow Search Algorithm,ITSSA）and introduces Iterative chaotic mapping,adaptive t distribution and nonlinear sine cosine strategy to construct the water ecosystem health evaluation model of ITSSA-PP.Finally,the Shandong Peninsula Blue Economic Zone is selected as the research area,which is the first land-sea integrated economic zone with the theme of marine economy,guided by the concept of green sustainable development,but its water ecosystem is under great and constant pressure.In this paper,the proposed water ecosystem health evaluation model is applied to the Shandong Peninsula Blue Economic Zone’s water ecosystem health from 2016 to 2020,and the water ecosystem health of each prefecture-level city in the region was analyzed in depth.Based on the horizontal and vertical analysis of the evaluation results,it can be seen that the overall water ecosystem health evaluation value of the Blue Economic Zone in Shandong Peninsula increased from 8.2313 to 12.8146 during 2016-2020.The health status has been continuously improved,but it still didn’t reach a healthy state.Water ecological management measures still need to be refined.The water ecosystems of Qingdao,Yantai and Weifang are in poor health and bad status throughout the year among the prefecture-level cities included in the Shandong Peninsula Blue Economic Zone,so the industrial structure needs to be further adjusted.Weihai,Rizhao and Binzhou are in good and sub-health status all the year round.The prefecture-level city with the best health status is Dongying.Its water ecosystem has reached healthy state in 2020,and the evaluation value has been in the top three during the five-year period.Through the analysis of the current status of domestic water ecosystem health management in Shandong Peninsula Blue Economic Zone,combined with the results of water ecological evaluation in this area,and puts forward management suggestions from three aspects: comprehensive utilization management of water resources,prevention and control of water ecological pollution,and optimization of industrial structure and spatial layout.