Construction And Evaluation Of The Index System Of Environmental And Ecological Water System Security

Watershed resources are the essential natural basic conditions for economic development and people's lives in a watershed.The security of the water resources environment determines the development prospects of the region and the health of the people's lives.In this paper,the Daxia River basin is an important upstream branch of the Yellow River Basin.It is also the main source of domestic water and agricultural irrigation in Linxia Hui Autonomous Prefecture and Gannan Tibetan Autonomous Prefecture.The Daxia River runs through Hezuo City Xiahe County and Linxia City.Its river length is 22.4 kilometers.More than 80% of the industrial and agricultural production water,residents' domestic water and ecological water in the surrounding area are the Daxia River.The Daxia River has developed in this region.Plays a vital role.Therefore,strengthening the awareness of saving water and controlling water pollution,and strengthening the unified management of water resources in the Daxia River have important practical significance for its rational development and effective use.This article aims to explore an efficient and practical water safety evaluation method.The overall research ideas of the thesis are as follows: First,the "pressure-stateresponse"(PSR)model is established and combined with the analytic hierarchy process(AHP)to establish a clear hierarchy of the Daxia River Basin water safety evaluation index system.Secondly,in order to improve the data validity of the water safety evaluation index system of the Daxia River Basin,the rough set conditional information entropy method is used to assign corresponding weights to each index.Finally,in order to calculate the water safety comprehensive index of each sub-basin of the Daxia River more precisely and accurately,the comprehensive index method is used to divide the safety grades and further comprehensive evaluation of the water environment safety.This article is based on the PSR framework model which is popular in the world,combine with the principles of index construction,start with three perspectives of pressure,state and response,and combine with the seven aspects of "socioeconomic pressure","water resource pressure","geographic environmental pressure","water resources utilization status","water quality status","socio-economic response","environmental protection and governance response",28 index factors were selected,finally,the water security evaluation index system of Daxia River Basin is constructed.The research uses rough set conditional information entropy to determine the weight of the comprehensive evaluation index system of water environment safety in the study area.Combined with the constructed index system and its weights,the comprehensive index evaluation method is used to calculate the above indicators,and the comprehensive indexes of the seven sub-basins of Daxiahe in 2017 were Sangke 0.4944,Tongren 0.5041,Xiahe 0.5178,Hezuo 0.5029,Ganjia 0.5067,Shuangcheng 0.4752,Zheqiao 0.5137.The comprehensive indexes of the seven sub-basins of Daxiahe in 2018 are Sangke 0.5063,Tongren 0.5379,Xiahe 0.5131,Hezuo 0.4743,Ganjia 0.5055,Shuangcheng 0.5050,Zheqiao 0.5026.The evaluation results show that the water environment of the Daxia River Basin is in a safe state during the evaluation year and has a tendency to rise slowly.This provides a theoretical basis for the construction of the safety assessment system of the basin's environmental ecological water system.