Study On Water Environment Protection Of Urban New Area Based On Landscape Pattern And Sponge City Construction

The current domestic water environment protection task is still very arduous.The water quality of Nanning city rivers are basically poor Grade V,according to the "Water Pollution Prevention Action Plan",as the capital city of Guangxi,Nanning has a task which is basically eliminated the malodorous black river in the end of 2017.The improvement of water environment now be under extreme pressure.This paper takes the first phase portal area of Guangxi Dragon Valley International Tourist Resort as the research object,combined with environmental status quo and the problems encountered in planning the implementation process of Nanning City and the study area,based on the idea and requirements of sponge city construction in Nanning,through regional status remote sensing images and regional planning map,the formation of land use and landscape type vectorization data are interpreted.To synthesize the changing of land use or land cover and landscape plaque characteristics,heterogeneity,water network characteristics,and so on,into a analysis of landscape ecological pattern change.The impact of the planning and implementation on the water environment function of the study area,and put forward the optimization measures,the main conclusions are followed:(1)In the study area,the diversity of vegetation types is generally the same,and the total area of the study area is 48.76%.After the implementation of the planning,the diversity and evenness index of the study area were increased.Among them,the largest change of vegetation type was timber forest,and 606.05 hm2 was converted into the landscape type of residents and construction land,green land vegetation,water and road.After the completion of the construction of the "warm coniferous forest-dryland-timber forest"characteristics of the agricultural and forestry products to provide the function to the "green vegetation-water-road-residents and construction land" as the leading urban development function shift.(2)According to the characteristics of the landscape pattern and the existing environmental constraints after the completion of the study area,combined with the requirements of the sponge city construction,taking the 80%target of the annual runoff control rate target,the main measures of "infiltration"and "storage",the use of permeable pavement,concave green space and green roof and other feasible low-impact development measures to achieve the construction of green land per unit area control runoff capacity of 81.8m/hm2,the remaining construction land control indicators in 212.1～235.5m3/hm2 to achieve surface runoff control of regional surface runoff.(3)The reasonable optimization of the regional eucalyptus was formed by Pinus massoniana,which was supplemented with broadleaf trees such as Liquidambar formosana,Rhizoma verdii,Castanopsis and Cinnamomum camphora.Improve the forest water conservation capacity at the same time for the heron nest to provide adaptation of woodland.(4)In the process of urban construction,the ecological attributes of the river and the concealment of the river should be paid attention to.The width of the vegetation buffer zone is set at 15m～30m.Chooseing good water conservation plant which with a certain amount of pollutant adsorption capacity and take into account the heron foraging activities of ecological and ornamental function such as Canna、Cortaderia selloana、Iris wilsonii。This study can provide reference for the planning and construction of sponge city in Nanning City,and provide theoretical basis and technical support for the improvement of urban ecological environment and the realization of river water environment protection goal in urban rapid development.