Construction Of Green Stormwater Infrastructure System (GSI) In Small Cities Based On Stormwater Management

At present,human’s excessive construction activities beings have caused a series problems.In the area of variable weather,the form of urban rainstorm and flood disasters is becoming increasingly severe.When people are attracted by the idea of "seeing the sea in big cities",the methods of stormwater management in small cities lag behind,which need more attention and rescue.At present,the design of stormwater pipe network in small cities generally fails to meet the standard of return period,and the current water management mostly adopts engineering measures with single objective.Traditional technology-oriented stormwater management methods are not only the root cause of the current severe challenges in urban systems,but also their inherent characteristics make them unsuitable for solving the sustainability problems in the future.Green infrastructure theory put the urban open space to form a green network with support and service functions.Multiple scales and various types of green stormwater infrastructure scattered arrangement in this green network,forming a retention,storage,purification effect of multifunctional water treatment system,can not only control the rain from its source,reducing load grey urban infrastructure of stormwater,also can realize the entire aquatic ecosystems compound environmental,economic,and social benefits.The research object of this paper is a small city with a population of less than 500,000 in the rainfall concentrated area in China.On the basis of analyzing the development of stormwater management and the new practice of stormwater management,this paper summarizes the shortcomings of urban stormwater management in China,as well as the limitations of GSI planning and construction in concept management,policy norms and technology.Then,the construction method of GSI system and the planning and design strategy of GSI are elaborated.The details are as follows:(1)Summarize the main points the classification and application of green stormwater infrastructure,and introduce the obvious advantages of green stormwater infrastructure from the aspects of stormwater regulation and storage,ecological environment improvement,ecosystem service provision,and municipal facility cost reduction,and expound the application and implementation process of green stormwater infrastructure.(2)The theory of "stormwater security pattern" was introduced into the construction of GSI system,and the "GSI-SCS" stormwater inundation model was established to simulate the potential inundation range of the city under different return periods,and the key locations of stormwater control were pointed out macroscopic,providing technical support for the targeted site selection of green stormwater infrastructure.(3)From the perspective of site suitability,the constructability of green stormwater infrastructure in low-safety and medium-safety areas of urban stormwater is analyzed.(4)The suitable land types and site characteristics of common green stormwater infrastructure are summarized,and the comparison and selection mechanism of green stormwater infrastructure is quantified.Specific methods of facility comparison and selection are proposed according to the requirements of total amount control of stormwater runoff,pollutant control and project cost control.(5)Taking Jing County,Anhui Province as a case,the applicability and feasibility of the GSI system construction method are demonstrated.(6)At the level of river basin,the water system,mountains,forests,farmland and other green infrastructure should be protected;At the level of urban blocks,it is proposed to control the source,transmission and discharge of stormwater runoff.At the level of community,the GSI specific design strategy of multi-functional district stormwater comprehensive utilization mode integrating "infiltration underground","collection and reuse" and "control and discharge" functions is constructed.