| Water is the source of life and closely related to the survival and development of mankind.Since the beginning of the 21st century,the scale of urbanization in China has been expanding.The construction of tall buildings and impervious ground has reduced the rainfall infiltration and the storage capacity of rivers and ponds,making it more and more difficult for cities to withstand floods.Population growth and industrial economic development make urban sewage discharge increase with each passing day,and aggravate the pollution of river water body.Wetlands such as rivers and lakes in cities are gradually losing,river networks and water systems tend to fragmentation,and aquatic ecosystems are becoming increasingly fragile and unable to maintain a good ecological environment.Nowadays,the issue of water safety,water pollution and water ecology has aroused widespread concern in the community,it is imperative to study for the urban water problems.In this paper,Yangzhou Biodiverse and Sci-Tech City is the research area,and three main water problems are analyzed:the waterlogging of the core area,the control of water pollution and the protection and restoration of water ecology.These problems are systematically studied and the solutions are put forward,the main achievements are summarized as follows:(1)Planning the construction of drainage pumping stations in the core area of Biodiverse and Sci-Tech City,optimizing the selection scheme of pumping stations and putting forward reasonable operation opinions to ensure water safety in urban areas.Based on the basic principle of unsteady flow and the software HEC-RAS,the highest water level of the river under different types and numbers of pumps is calculated by using the unified modeling of the river course-pumping station,and compared with the control water level,the optimal planning scheme of the pumping station under the 20 years standard of waterlogging is obtained.Discriminating the location and time of waterlogging dangerous reach in order to put forward the operation monitoring opinion of pumping station in flood period.By simulating the operation effect of pumping stations in different recurrence periods,the river pre-drainage scheme which encounters 50 years of rainfall and the reasonable operation scheme of pumping station which encounters 5 years of rainfall,are formulated.(2)Through the scientific evaluation and reasonable analysis of Biodiverse and Sci-Tech City's surface water quality,pollution control measures with sources of pollutants comprehensively are proposed to improve urban water pollution.This paper investigates and monitors the water quality of rivers in the Biodiverse and Sci-Tech City.Single factor index evaluation method and fuzzy comprehensive evaluation method are used to evaluate the water quality.The main pollutant indexes of point and non-point source pollution,such as COD,BOD5 and ammonia nitrogen,are calculated and the causes of water pollution are discussed.According to the analysis of the causes,the treatment measures including pollution source control and pollutant reduction are put forward for the sake of water quality improvement.(3)In order to restore and reshape the urban water's ecology health,the restoration countermeasures are selected according to the local conditions and present situation of the water ecology protection area in Biodiverse and Sci-Tech City.This paper analyzes the objectives and ideas of regional water ecological restoration,and puts forward specific water ecological protection strategies and engineering restoration measures.These include wetland conservation strategies,selection of appropriate ecological restoration techniques,implementation of clean water and living water projects,planning of urban ecological landscape rivers and advocating low-impact development and construction,which can provide reference for other cities while maintaining water ecological health. |
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