Study On The Evaluation Of Water Ecological Security Status Of Sanhekou Reservoir Based On DPSIR Model

Over the past few decades,the rapid development of water conservancy engineering construction in China has not only promoted social and economic development,improved people’s lives,and regulated uneven distribution of regional water resources,but also had an impact on the ecological and environmental benefits of engineering construction areas.Therefore,ecological security evaluation of water conservancy engineering construction areas is an important guarantee to ensure regional ecological security.The Sanhekou Reservoir is one of the important future water sources in the Guanzhong region,responsible for regulating,storing,supplying water,and generating electricity.In order to explore the water ecological security of Sanhekou Reservoir in the context of water conservancy engineering construction more effectively,this article takes Sanhekou Reservoir as the research area,based on historical survey data and the results of the research team’s on-site sampling survey in Sanhekou Reservoir,and uses the DPSIR model to construct the water ecological security index system of Sanhekou Reservoir.Using the entropy weight method to calculate indicator weights,unifying the transformation of indicator variables and evaluation models,obtaining standardized ecological environment effect scores,analyzing the distribution characteristics and influencing factors of evaluation indicators,and completing the evaluation of the water ecological security status of Sanhekou Reservoir from 2013 to 2021.The main conclusions are as follows:(1)The water quality of Sanhekou Reservoir is between Class Ⅱ and Class Ⅲ,and the overall water quality is good.The water quality evaluation results of the water quality comprehensive pollution index method and the Nemero comprehensive pollution index method are consistent with the single factor water quality evaluation results.Both the Puhe River and Wenshui River have good water quality,and the overall trend shows that the upstream water quality is better than the downstream water quality.Through high-throughput sequencing,a total of 45 water samples,121 classes,326 orders,576 families and 1375 genera were collected.According to the results of two sampling analyses,the species richness index and evenness index at the Jiaoxi River site are the highest,indicating good microbial diversity and evenness in Jiaoxi River.(2)Phytoplankton,Zooplankton,fish and benthos in Sanhekou Reservoir were sampled and investigated.Among them,the survey of Phytoplankton shows that Diatoma and Chlorophyta are the dominant species and genera,and Diatoma is the Absolute advantage group.The investigation results of Zooplankton show that the Zooplankton in Sanhekou reservoir area is mainly Protozoa and rotifers,of which Protist is the Absolute advantage species.A total of 37 species and 879 fish were caught during the two catches,belonging to 3 orders,8 families,and 31 genera.There are 24 species of Cypriniformes,which are the dominant populations in the Sanhekou Reservoir area.A total of 11 orders,18 families,and 21 genera of benthic animals were collected during the survey,with the order Ephemeroptera having the most species and 6 genera being the dominant population.(3)The evaluation index system for water ecological security of Sanhekou Reservoir based on DPSIR model,with the target layer being the ecological environment status of the research area,and the plan layer being composed of driving force(D),pressure(P),state(S),impact(I),and response(R),respectively,reflecting the composition criteria of the evaluation index system for aquatic environment status of Sanhekou Reservoir.Evaluate the water ecological security of the Sanhekou Reservoir Area through the indicators of driving force layer,pressure layer,state layer,impact layer,and response layer.The factor layer further subdivides the scheme layer into a total of 13 indicators.The indicator layer further subdivides the 13 factor layers into quantifiable specific indicators,which can quantitatively evaluate the water ecological security status of the Sanhekou Reservoir.(4)The comprehensive evaluation results show that there were differences in the water ecological security status of Sanhekou Reservoir from 2013 to 2021.The water ecological security evaluation results of Sanhekou Reservoir from 2015 to 2020 were good,and the evaluation results from 2013,2014,and 2021 were all excellent.The evaluation results of each subsystem also show temporal differences.During the period from 2013 to 2021,the contribution rate of the state index to the water ecological security of the Sanhekou Reservoir Area was the highest,and the evaluation values of the pressure index and impact index in 2013 were much higher than those in 2016.In terms of driving force indicators and response indicators,there was no significant change in the evaluation values between 2013 and 2021,indicating that the construction of water conservancy projects has had a certain impact on regional water ecological security.