Construction And Application Of River Health Assessment System In The Jiamusi Section Of The Songhua River Mainstrea

Under the background of the construction of ’ Happy River ’,this paper selects Jiamusi section of Songhua River as the research object,introduces the unascertained measure theory,establishes the river health evaluation model,carries out the river health evaluation research,and analyzes its healthy development status and influencing factors.The main research contents of this paper are as follows:(1)Based on the characteristics and current situation of the Jiamusi section of the Songhua River,from the five aspects of water environment,aquatic organisms,land environment,river morphology and structure,and social service function,a river health evaluation index system covering 12 suitability indicators was constructed,including ecological flow satisfaction,dissolved oxygen water quality,oxygen-consuming organic pollution in water,macroinvertebrate biological integrity index,fish retention index,soil and water conservation rate,natural wetland retention rate,NDVI index,river lateral stability coefficient,river bank stability,navigation water level guarantee rate,and public happiness satisfaction.The threshold of each index is adjusted accordingly,and the river health degree is divided into four grades.Coordinate and unify the administrative boundary,hydrological monitoring section and environmental monitoring section,and divide the Jiamusi section of Songhua River into three sections for research.Taking 2020 as the level year,the measured values of each index were collected through field investigation and literature review.The AEW method is used to calculate the objective weight of the index,and the improved G2 method is used to determine the subjective weight of the index.Finally,the Lagrange multiplier method is used to obtain the comprehensive weight of each index.(2)The unascertained measure evaluation model was used to calculate the measured values and health levels of each river section by establishing a single index measurement matrix,establishing a multi-index measurement matrix and confidence recognition.The results showed that the river was in a healthy state.There were 7 health and above health level indicators,including ecological flow satisfaction,dissolved oxygen water quality,macrobenthic invertebrate biological integrity index,soil and water conservation rate,natural wetland retention rate,navigation water level guarantee rate,public happiness satisfaction,accounting for 58.3 % of the 12 evaluation indicators;there were 5 sub-health indicators,including the status of oxygen-consuming organic pollution in water,fish retention index,NDVI index,lateral stability coefficient of river channel and bank stability,accounting for 41.7 % of the 12 evaluation indicators,and there was no inferior index.