Study On The Differences Of Rain Garden Design Norms Between China And The United States

Technical standardization is of great significance to the economy,science and technology,and the revision and improvement of the standard system of sponge city construction will effectively promote the healthy development of sponge city construction in China.Rainwater garden technology is a typical single sponge technology facility,which can effectively control rainwater runoff.Based on the comparative study of the classification,scale calculation,section design,engineering construction and operation and maintenance of the current design norms of rainwater garden in China and the United States,combined with the application status of rainwater garden in China,this thesis puts forward the rationalization suggestion of the revision and perfection of rainwater garden design norms,and gets the following conclusions:(1)The differences between the classification of rainwater gardens in China and the United States are expounded from the four aspects of structure,performance,application area and other classification.It is suggested that the specific application types of rainwater gardens,distinguished by pollutant type and concentration,the specific design requirements for the application of individual rainwater garden technical facilities in roads,parking lots,residential areas and other areas should be improved,the buffer zones of different types of rainwater gardens should be required,and the rainwater gardens of existing different projects could be evaluated to increase the design purpose and classification of design projects.(2)Comparing the three methods of volume,water balance and flow,summarize the applicable scope,precautions and calculation formula of the design method of stormwater garden facility,and study the similarities and differences of the three design calculation methods through case study.The results show that the calculation results of the three methods are from large to small: volume method> water balance method >flow method.When the volume method can be selected mainly by rainwater runoff control and the water balance method or flow method by runoff pollution control,the flow method value must be satisfied.(3)In the design of rain garden section,the main facilities and ancillary facilities 2parts to compare and analyze.It is pointed out that the design height of reservoir in the main facility should be related to the drain time and soil permeability coefficient,and the requirements of the emptying time in 28 states of the United States are analyzed statistically.In the auxiliary facilities into the water,China’s norms should consider the uniform flow of rainwater,in the drainage,should be based on the rainwater runoff to consider whether the drainage pipe opening rate can ensure that rainwater can flow out smoothly,while perforated position is recommended to be set in the bottom of the pipe.(4)In the construction and operation and maintenance of rainwater garden project,the construction of the project mainly from the soil texture,construction process,node construction,post-work to discuss;China’s soil and water conservation technology can refer to the relevant national standards,it is proposed to set up in the rain garden area outside to ensure construction safety,rain garden operation and maintenance needs public participation,through the development of simple and clear maps,tables,the use of incentives,activities and other forms to allow the public to participate in the rain garden simple daily maintenance.