| A healthy basin water ecosystem is the basis for ensuring sustainable economic and social development in the basin.Ecosystem health means that the ecosystem does not respond to patients,is stable and sustainable development,and the health of the basin will change with the composition of its biological community.That is to say,the change of biodiversity in river water will lead to the change of their health.Weihe is the first largest tributary of the Yellow River,which flows through three provinces of Shaanxi,Gansu and Ningxia.It is an important river in Northwest China.In recent decades,in response to the call of the state,the development of industry and the acceleration of urbanization,human disturbance on the basin's water environment has become more and more serious.The problems such as waste of water resources,wastage and vegetation destruction in Weihe basin are becoming more and more prominent.As well as extensive and single harvest agricultural production mode,people's awareness of watershed protection is poor,causing serious soil erosion and water ecosystem health.An appropriate health evaluation standard system can be used to assess the health status of the watershed ecosystem.It can not only understand the current health status of the river basin,but also determine the degree of interference of human activities to the water ecosystem of the river basin,and also provide a scientific basis for river management decision-makers and managers to formulate relevant river basin management policies.The main methods and conclusions are as follows:(1)In June 2019,on the basis of field surveys of physical habitat,water quality and phytoplankton collection at 24 sampling sites in the Weihe River Basin,the principal component analysis method was used to calculate the weights of the evaluation indicators.The 11 evaluation indexes were selected to build the health evaluation index system and health evaluation standard system of Weihe river basin ecosystem.The grey correlation degree mathematical model is used to evaluate the water ecosystem health status of 24 sampling points in the Weihe River Basin.Based on the characteristics of the three major river systems in Weihe basin,the health status of different river systems is analyzed in order to provide theoretical basis and technical support for river management and ecological restoration in Weihe River Basin.(2)According to the determination of river habitat index(CHQI),the physical habitat quality of each sampling point in the Weihe river basin is at a relatively good level.Through the calculation and analysis of the water quality assessment index(CWQI),the water quality of each sampling point in the Weihe basin is at a poor level.The range of the Shannon Weil Shannon-Wiener diversity index is 0?3.0694,24 sampling points.More than 20 sampling sites have different degrees of pollution,indicating that the overall water quality is not very good,there is pollution,water ecosystem health is not very good.(3)The grey correlation model was used to assess the health status of the Weihe River Basin.The results showed that there were 5 health sampling sites,0 sub-health sampling sites,2 general sampling sites,11 poor sampling sites,and 6 other sampling sites with poor results.19 sampling sites were below the general level of health assessment,and the overall health condition of the Weihe River Basin was poor.Regional water ecological health is showing a trend of gradual increase from northwest to Southeast.There are obvious regional differences in water ecosystem health.The river health assessment in Weihe river basin can not only improve the understanding of the overall situation,but also provide scientific basis and technical support for further research,and can provide guidance and suggestions for the government. |
PDF Full Text Request