Research On The Quantification Method Of Green Belt Index In Hilly Cities From The Perspective Of Rain-Flood Security

In recent years,with the continuous expansion of cities,urban rain-flood disasters in our country have become more and more frequent,and the contradiction between urban construction and urban rain-flood disasters has become more and more obvious.A large number of researchers have shown that urban green belt has the functions of water storage,water retention and water purification,and plays an important role in solving the problem of urban rain-flood disasters.Urban green belt is also an important carrier in the planning and design of "The Sponge City".However,the urban green belt system plann in g i n C h i na,u se s t he p er c a pi ta green belt area index method to predict the total size of urban green belt,which does not fully consider the necessity of rainfall flood management and rain-flood management in the c it y,and cannot ensure that urban green belt planning meets the requirements of rain-flood security.need.Therefore,from the perspective of rain-flood security,this paper explores and optimizes the urban green belt index quantification method for hilly cities in southern China.There are many researches on the estimation system,function and information technology adhibition of urban green belt,which play an important role in the development of urban green belt planning in China.With the frequent occurrence of urban rain-flood damage,the ecological function of urban green belt,especially its flood regulation and storage capacity,has gradually become a hot topic of current research.From the perspective of rain-flood management,a large number of studies have used urban rain-flood model to simulate the qualitative and quantitative effects of urban green belt on urban rain-flood damage.These studies have proved that the rain-flood regulation and storage effect of urban green belt should be considered in planning and index determination of urban green belt.However,from the visual angle of rain-flood security,there are few researches on the control of the total size of urban green belt at the macroscopic viewIn view of the lack of quantitative research from the perspective of rain-flood security in the current urban green belt research,this study will supply a calculation method for the gross of urban green belt from the perspective of rain-flood security.As instructed below shows the general manipulations of this specific calculational method:firstly,the maximum amount of rainwater stored in urban green belt per unit area is calculated from three aspects:soil saturated water content,soil infiltration rain-flood volume,and surface vegetation interception volume,and then the urban rainwater flooding is carried out through the FLO-2D model.The urban rain-flood inundation amount calculated by the simulation is divided by the two to calculate the total urban green belt required to meet the urban rain-flood security.Finally,the total amount of urban green belt from the perspective of rain-flood security is compared with the total amount of urban green belt calculated by the current planning method,and the gross of urban green belt is acquired.In order to verify the feasibility of this method,this study took the Chengbei New District of Quanzhou County,Guilin City as an example for empirical application.The study found that to meet the goal of rain-flood security,it is necessary to add 309,342.86 square meters of urban area to the existing and planned green belt.Green belt,and layout urban green belt in combination with urban waterlogging risk areas.This case proves that the method has certain feasibility and provides a reference for the determination and layout of the total amount of urban green belt.Under the background of the national land use and belt planning,the method guidance can be put forward in the process of urban green belt planning,and optimization ideas can be proposed for cities that have formulated urban green belt planning.