Health Evaluation Of The Inflow River Of Erhai Lake

The inflow river is a special river. It is an important part of the ecological environment of the lake basin. As China’s economy continues to develop,inflow rivers are subject to different degrees of human disturbance. There are water pollution, river channelization, serious damage to the ecological health of rivers in different types of inflow rivers.It is difficult to transport clean water into the lake for these inflow rivers. River health assessment was urgently needed to provide a scientific basis for the regulation of inflow rivers.This paper draw on relevant research results combined with the characteristics of inflow rivers,which in the west of Erhai Lake.Then, river health assessment system,which was suitable for the west of Erhai Lake,was builded.And this system was applied in those inflow rivers,which in the west of Erhai Lake. Research results Showed:(1) This paper reviewed the development process of the river health connotation, river health evaluation index system and river health evaluation method. And some current problems existed in the field of river health evaluation were proposed.Then the health connotation of the inflow river was proposed by combining with the existing river health connotation and the characteristics of the inflow river.(2) This paper builded the river health evaluation index system and assessment criteria,which were suitable for the inflow rivers in the west of Erhai Lake by combining the reference of classic cases in the field of river health assessment and the main features of the inflow rivers in the west of Erhai Lake.(3) By comparing the current weight determination method and the evaluation method in river health assessment field,comprehensive weight method and comprehensive index method were selected to apply in this study.(4)The river health assessment system established in this paper was applied in the Baihe River,which is one of the inflow rivers in the west of Erhai Lake.The results showed that the wet and dry seasons were in phase between the sub-health and slightly morbid,and wet season’s health composite index was significantly higher than the dry season.Then the main indicators were analyzed. Hydrology indicators reflected that the use of water resources in Baihe River was unreasonable.Water quality indicators reflected the sources of pollution in Baihe River. Aquatic biological indicators reflected the Baihe river’s features. Local tourism had brought serious problems of environmental pollution from the trend of the main indicators of view.(5) The river health assessment system established in this paper was applied in the main nine inflow rivers in the west of Erhai Lake. The results showed that Yang River,Mngyong River and Lingquan River were in phase between health and sub-health,Jin River,Yinxian River,Zhonghe River,Long River and Mocan River were in phase between the sub-health and slightly morbid.By studying their distribution,the results showed that health index score of the western inflow rivers has a decreasing trend from north to south due to the influence of human. Then each indicator was analyzed. the results showed that there were serious water pollution, ecological degradation of rivers and river services degradation in those inflow rivers,which in the west of Erhai Lake.