Study On The Rainwater Storage Transformation Of Sponge City In The Serious Waterlogging Street Blocks

In recent years,the excessive development and construction of urbanization has led to serious damage to the ecological environment,produced a series of problems,such as urban waterlogging.The waterlogging have great impact on the normal life and production of the residents.Besides,it has brought great economic losses to the towns and countries.The street block is the basic unit of urban structure.Therefore,it is of great practical significance to study on the rainwater storage transformation of sponge city in the serious waterlogging street blocks.This paper takes Fengcheng street area as the simulation object.The S WMM model was used to study the following things:First,I carry out the relevant literature review and collation work.Then,I went to collect the data of the hydrological characteristics,the topographic map,drainage network map and actual drainage pipe network of the research area needed for SWMM modeling.After the above work,the rainwater runoff model of the drainage system in the studied area was constructed in SWMM.Through the operation results of SWMM model to analyze the hydraulic characteristics of the rainwater harvesting system and the occurrence of waterlogging in Fengcheng town,Lianjiang County under different rainfall intensities events.According to the overload condition of each node and pipe section in the area,the waterlogging area that needs to be studied is determined.Then,the five kinds of sponge city rainwater storage schemes were designed to analyze the.effects of rainwater regulation,project cost and environmental impact on the transformation of different rainwater storage schemes under different rainfall events.Finally,according to the comprehensive benefits of different rainwater storage schemes,the priority order of each rainwater storage plan under the design standard of high and low rainfall is summarized.In this paper,through the analysis of the results of the model,the following conclusions are obtained:(1)The capacity of the existing rainwater pipe network is obviously insufficient in Fengcheng Town,Lianjiang County.There will be occur some pipelines full load in the event of a2-year event.The greater the recurrence period,the more serious the node overflow and pipeline overload.The main reason is due to the lower design standards of the old pipeline.In addition,after the urbanization,the peak flow rate increases,the peak is ahead of time,the runoff coefficient becomes larger and so on.Those factors also will lead to the above phenomenon.(2)During the 180 min rainfall event,the runoff in the rainwater pipeline reaches the peak flow at about 80 min.To construction of different rainwater storage measures in the vicinity of the "overload point" of the rainwater pipe network can effectively reduce the peak flow and the drainage pressure of the pipe network.(3)The following is the priority order of the rainwater storage plan under the design criteria for the high and low rainfall recurrence period:Under the design criteria of medium and low recurrence period,the priority order of rainwater storage plan is as follows:LID rainwater storage measures + pipe regulation+rain transfer reservoir>LID rainwater storage measures>Adjust the pipe system>Construction of rainwater storage>Rain water discharge channelUnder the design criteria of high recurrence period,the priority order of rainwater storage plan is as follows:In the case of an open space which can be used as a drain channel:Rain water discharge channel>LID rainwater storage measures + pipe regulation+rain transfer reservoir>Construction of rainwater storage>LID rainwater storage measures>Adjust the pipe system;In the absence of open space can be used as a drain channel:LID rainwater storage measures + pipe regulation + rain transfer reservoir>Construction of rainwater storage>LID rainwater storage measures>Rain water discharge channel>Adjust the pipe system.