Research On Optimization Of Urban Surface Water Environment Based On Landscape Ecology Theory

Water is a resource for urban development and an important part of the urban landscape ecological environment.Water and green together constitute the urban ecological background.However,in the process of rapid urbanization,as the underlying surface of the city is changed,the natural water system space is greatly transformed,the natural hydrological process is disturbed and becomes disordered,the connectivity of the urban water system decreases and becomes fragmented,and the urban environment is resistant to water Due to the great attenuation of the degree and the storage capacity,coupled with the continuous heightening of the dike project,most of the rainwater cannot flow into the water body.At the same time,with the siltation of the river channel and the increase of the river bed,many southern urban river channels are gradually It became a"hanging river",which also caused multiple water environment problems such as urban drought or waterlogging.Therefore,in the context of the sponge city,how to comply with the natural hydrological process in the urban environment to the greatest extent,connect the broken water body,improve the landscape connectivity of the urban water system,and restore the ecological self-regulation and self-purification ability of the water system,thereby optimizing the urban water environment to promote the sustainable development of urban ecological environment is the main purpose of this study.From the perspective of landscape architecture,the thesis uses landscape ecology theory as an important guarantee for creating a sustainable urban landscape environment,emphasizes its role in landscape ecology and spatial structure,and proposes to adapt to the natural hydrological process.Systematic urban water environment optimization strategies and methods for the purpose of connecting the network space of the water system and restoring the urban water ecological storage capacity.Taking the old city of Nanjing as a research object,based on the current status and historical evolution of the city,it analyzes the causes of urban droughts and floods in multiple dimensions,and proposes specific and specific optimization methods to alleviate urban water problems,improve urban ecological environment,and optimize water landscape quality,service city-scale sponge city construction,provide new ideas and ways.The main research contents and conclusions are as follows:1)From the perspective of hydrology,the relationship between urban development and hydrological process,spatial structure of water system and ecological capacity of water system is deeply understood,and the digital model of urban runoff generation and confluence is constructed by using SCS model and GIS technology,and the hydrological characteristics of urban environment is analyzed.2)Using related landscape ecological indicators,combined with the time dimension,the characteristics of changes in urban water system structure,water network connectivity and water system storage capacity in different periods are quantitatively studied and analyzed,and the change effects of the three characteristics are discussed.3)Using the method of quantitative spatial network analysis and from the perspective of landscape connectivity,the paper uses Gis,Conefor and Urban Network Analysis tool(UNA)as the main tools to evaluate the connectivity importance of regional rivers and confluence points,and provides the basis for improving the connectivity of regional water network.4)Combined with the analysis results,the optimization methods were proposed from three levels of water system ecological regulation and storage capacity,water network connectivity,and key areas,and the blue and green spaces of the city were rationally planned and arranged to achieve the optimization of the urban water environment.According to the distribution characteristics of runoff,the distribution storage capacity is calculated for the catchment units with high production flow to construct corresponding storage areas to restore the original storage capacity of the city.At the same time,combined with the distribution of urban flood-prone areas and river chains and nodes with important landscape connectivity,the overall water network is optimized.Use gray,blue,and green infrastructure to transform,optimize,and upgrade key areas under the premise of satisfying urban functions.5)In view of the water environment problems and the changes of water systems in the old city of Nanjing,the paper proposes that a total of 33.09(10~4m~3)newly added storage areas are distributed in 15water collection units with large runoff to restore the city's original ecological storage capacity and achieve Reasonable allocation of water resources by cities and the construction of urban blue-green networks;restoration of three river channels with important landscape connectivity significance in the city:Inner Qinhuai River North Section(Hongwu North Road Bridge-Wulongtan),Qingxi(Xuanwu Lake-Inner Qinhuai River North Section),Dongwuyun Du(the middle section of the inner Qinhuai River-the inner section of the inner Qinhuai River),effectively improve the overall connectivity of the urban water network and improve the urban landscape ecological service function;in key areas such as Jinxianghe Road,Daqiao South Road and Houbiaoying Road,according to the different types of land in the area,different forms of green infrastructure are set up and distributed in the context of the sponge city to simulate and improve the natural water cycle process and alleviate the surrounding waterlogging Situation,optimize the hydrological environment of these high-risk areas of rain and flood.Through the analysis of the old city of Nanjing,it can be found that the urban hydrological process is disturbed,the structure of the water system is destroyed,and the decline in connectivity and storage capacity is the root cause of urban droughts and floods.Therefore,based on respecting the hydrological conditions in the urban environment,communicating water systems to improve landscape connectivity,establishing storage areas to enhance the ecological storage capacity of the area,for optimizing the urban hydrological environment,building a good ecological landscape system and sustainable urban development Models have important positive meanings.