Regional Water Ecological Security Evaluation Based On W-SENCE-PSR Framework—A Case Study Of Hexi Inland River Basin

Water ecological security is a matter of human health and social economic stability in the river basin,national comprehensive governance and the high-quality development of river basin in the Yangtze river basin and Yellow River basin,which put water ecological security to national strategic height.The continental river basin in the northwest of China is the driest areas,the recession phenomenon in the hydrological cycle and ecological function,the ecological environment deterioration,and there is the risk of systemic water crisis.Therefore,research on inland river basin water ecological security evaluation is particularly important.Although there has made a lot of research achievements,there are also many shortcomings,the water ecological system structure frame and the basic attributes of water ecological security to analysis is not use enough;Insufficient research on the trend of the development of the water ecological security,Ignore the evaluation index system framework which of analysis and optimization.So how to build the water ecological security evaluation index system framework which based on W-SENCE-PSR（the compound ecosystem of water as the main line-pressure state response model）?How to apply ecological related theory to optimize the water ecological security evaluation index system?How to comprehensive analysis water ecological security status quo and trend analysis in continental river basin,and put forward corresponding control countermeasures?Therefore,in this study,taking inland river basin in Hexi as the research object,using the improved niche breadth,fuzzy system analysis to determine the index weight and BP neural network model to determine the index prediction,optimization evaluation index system,using the fuzzy comprehensive evaluation method to evaluate the water ecological security situation in three inland river basin from 2009 to 2018based on the related data,to analysis the present and trend situation,to determine the system control strategy,to screen of the main influence factor,provide data support for the inland river basin water ecological safety regulation.Firstly,water ecological security evaluation index system analysis of the inland river basin.Reference for related research,redefine the concept of water ecological security.The connotation of the water ecological security（extension from the basic attributes of water）involves the economy,society,resource,environment and ecology subsystem,and involved in the actual response of the state of the water ecological security（PSR）,at the same time also reflected the status evaluation assessment and prediction of time factor,the process also reflects the process of composite system function changes.Evolution process of water ecological security lies in the relationship between the interaction of water safety system（PSR）and relative factors（SENCE system）state security situation of development,due to the state system and the relationship between the existence of its own evolution,led to a safe state or unsafe condition.Water ecological security is the affect dimension（PSR）,field dimension（SENCE）,time,and security subject function,based on W-SENCE-PSR framework to establish the water ecological security evaluation system.Secondly,the optimization of the river basin water ecological security evaluation index system.Index Z4（farmland effective irrigation area of cultivated land area ratio）,Z19（flood water quality comprehensive index）,Z37（the affected area）,Z36（chemical oxygen demand（cod）emissions per unit area）,Z35（ammonia nitrogen emissions per unit area）,the index weight of the five indicators relative to the minimum and is less than 0.0167,the index niche breadth value relative to the minimum and is less than 6.03,predict the influence of the water ecological security are roughly neutral.which shows that the impact on the evaluation index system is small and adaptability is poor,the index will not become a restrictive factor,the five indicators will be removed in the optimization index system,finally got the evaluation index system which is composed of 33 indicators after the optimization.Thirdly,the water ecological security evaluation in the inland river basin.Using the fuzzy comprehensive evaluation method to status and prediction evaluation assessment of the water ecological security situation in the inland river basin.On the evaluation of the status quo,Shule river,Heihe,Shiyang river basin,annual average fuzzy comprehensive evaluation index are:0.5322,0.40545,0.303;the fuzzy comprehensive evaluation of forecast evaluation annual result in order:0.524,0.517,0.342.It shows that water ecological security situation in Shule river basin is best,but have a deteriorating trend in the future;Heihe river in the middle,there will be improved obviously trend;Shiyang river in the bottom,there will be improved small trend,but the gap is obvious,so take the water ecological security as the priority control area.Using the Improved health distance method get the health distance value of Shule river,Heihe and Shiyang river basin,the values in order are:0.468,0.595,0.697,shows that the ecological security situation of Shule river is the best,followed by in Heihe,Shiyang river,the results are consistent with the fuzzy comprehensive evaluation results,Illustrating the validity of the evaluation results from the side.Fourthly,the status quo and trend analysis of water ecological security in the river basin,confirmed the direction of system control.Respectively from the perspective of W-SENCE system and PSR system perspective analysis the water ecological security status quo and trend of river basin,In the situation assessment,water ecological security situation of subsystems in the Shule river basin is relatively the best,the comprehensive index average of each subsystem based on W-SENCE 0.1<Y_W-SENCE<0.127,the PSR system comprehensive index average 0.149<Y_PSR<0.228;Heihe river in the middle,0.08<Y_W-SENCE<0.115,0.116<Y_PSR<0.149,Shiyang river is the worst,Y_W-SENCE<0.08,Y_PSR<0.120;In the forecast evaluation,using the BP neural network model prediction result shows that eight positive influence indicators,10 negative impact index in the Shiyang river basin,Shule river basin are four impact indicators,eight negative impact indicators,there will be a deteriorating trend;Heihe river basin 12 positive influence indicators,eight negative impact indicators,there will be an improving trend.W-SENCE system and PSR system perspective prediction evaluation showed that the Shule river,Heihe river and Shiyang river basin environment subsystem is relatively the worst,the comprehensive evaluation index was in order:0.08,0.08,0.05,at the same time,the state system of the Shule river basins,the response system of the Heihe river basin and the pressure system of Shiyang river basin,which are relative to the worst,the comprehensive evaluation index in the order:0.143,0.141,0.104.From the perspective of the sensitivity of the system,the sensitivity of the Shule river is relatively high,10.3‰,its social subsystem and the pressure system are highest sensitivity,followed by 8.4‰,14.1‰;The sensitivity of the heihe river basin was 6.8‰,and the,the status of ecological subsystem and state system,the sensitivity is highest,followed by 6.5‰,12.0‰;Shiyang river sensitivity is lowest,3.2‰,the resources subsystem and system pressure sensitivity is highest,followed by6.2‰,12.7‰.Fifthly,the priority control indicators and countermeasures in the continental river basin.According to the system regulation focus in the three inland river basins,combined with health distance value and the index weight,which determines the top 10 priority control indicators YZ1（GDP per capita）,YZ20（mass ratio）,YZ13（water to the surface of the water supply ratio）,and so on,and got the concrete control countermeasures for each river basin.The water ecological security control indexes of Heihe river and Shule river basin are relatively concentrated distribution,but the regulation index distribution dispersed regulation widely in Shiyang river basin.We should pay attention to the precipitation changes of Shule river basin water adverse impact of the ecological security and its natural ecological environment vulnerability;Strengthen the control of livestock number,beware of pasture degradation caused by the overload problem.It plays an important role in improving water ecological security status when the water storage capacity ability of water is improved in Heihe river basin;pay much attention to the recycling of rainwater;Avoid industrial water and agricultural water from the ecological environment water,attaches great importance to strengthen the ecological environmental water.