A Study On The Health Evaluation Of Urban Rivers In Northern Water-scarce Areas

With the rapid development of social economy,water resource shortage has become a common problem in northern cities of China.In the process of rapid urbanization in north China,the problems of channelization,seasonal flow interruption,ecological function degradation and landscape effect deterioration appear in urban rivers.River health assessment is an effective tool to identify river problems and a prerequisite for river system management,restoration and protection.In order to expand the theory and practice of urban river health assessment in water shortage area,and to provide theoretical and scientific basis for the management,ecological restoration and reverse of urban river degradation in water shortage area,this paper carried out the urban river health assessment in water shortage area,taking nine rivers in Taiyuan city as an example.Firstly,this paper conducts a basic survey of physical geography,social economy,river morphology,and river ecology in the basins of the nine rivers in Taiyuan.Then,according to the current situation of the nine rivers in Taiyuan City,the assessment index was optimized,and 13 indicators including the comprehensive score of hydrology,the Shannon Winner index of river plants,the type of vegetation dominant in the river,and the coverage rate of the expressway along the river in the urban area were selected from the four aspects of hydrological water quality,river morphology,biology and social economy to establish an assessment index system suitable for the nine rivers in Taiyuan,and then combined with the analytic hierarchy method and the set pair analysis method,the river health assessment model suitable for cities in the water-scarce area was established,and the health assessment of the nine rivers in Taiyuan was carried out.The assessment results show that most of the nine rivers in Taiyuan are in a sub-healthy state,and some are in a healthy or unhealthy state.The state of hydrological water quality,river morphology and biology is poor,and the performance of socio-economic functions is more prominent.Finally,according to the results of the health assessment and combined with the actual situation of Taiyuan City,the restoration potential of the nine rivers was analyzed,and the ecological restoration goals and applicable technologies were proposed.The analysis believes that the ecological restoration of the nine rivers in Taiyuan can provide public green space and ecological landscape service functions for the city,but it faces the constraints of insufficient water resources and insufficient space;the short-term restoration goals of the urban section of the nine rivers should be to ensure the social service function,improve the hydrological status of the river,purify the water quality of the river and enhance the landscape function,and the long-term restoration goal is to expand the river space,restore the hydrological cycle of the river basin,and reshape the urban river ecosystem;the restoration goal of the mountain section of the nine rivers is to maintain the flood control function of the river and maintain the natural shape of the river.Promote pollution control and water conservation.The urban river health assessment index system established in this study objectively reflects the coercive effect of rapid urbanization on urban river ecosystems in northern China’water-scarce areas,reflects the phased characteristics of urban development,and the assessment results of the nine rivers in Taiyuan reflect the current situation and development trend of Taiyuan rivers,and the urban river health assessment model constructed is reasonable and feasible.