Roof Rainwater Source Control Technologies Based On Design Of Sponge City

The rapid urbanization process reduces the permeable undersurface in the city and changes the original natural water cycle.Urban waterlogging occurs frequently and rainwater resources are lost in vain in the rainy season,however,urban water resources are in short supply and underground water is over-exploited in the dry season.The contradiction between "water abundance" and "water shortage" highlights the defects of rainwater resources utilization and management mode.Decentralized rainwater source control technology is one of the key elements ways of sponge city concept in urban stormwater management.Based on the concept of sponge city,this paper takes urban construction roof rainwater as the research object to carry out the research on rainwater source clean and seepage storage control technology.It is of great significance to reduce the pollution load of rainwater runoff,relieve the pressure of drainage network,reduce urban waterlogging disaster and protect urban water environment.The research contents and conclusions of this paper are as follows:(1)Based on the theory of roof rainwater source clean and seepage storage,this paper designs a roof rainwater source clean and seepage storage device The results of the experiments show that the concentration of pollutants in the abandon box is significantly higher than that in the storage tank,and also significantly higher than that of the roof rainwater directly collected without split-flow of first flush runoff,indicating that the source cleaning has achieved good results.The rainwater storage and infiltration device can effectively harvest and infiltrate rainwater.In addition,The change trend of infiltration rate of non-pressure infiltration and that of pressure infiltration in rapidly-reducing period of rainwater source seepage storage device conform to power function distribution and stable period is linear function distribution.The R2 is greater than 0.75,which indicates that established infiltration empirical model is stable and reliable.(2)SWMM software was used to simulate and analyze the variation trend of pollutant concentration in the water storage tank,and results show that the attenuation of pollutant concentration in water storage tank has three periods:rapidly-reducing period,transitional period and stable period,and on the same kind of pollutant,the stable mass concentration of pollutant in the collection tank decreases with the increase of the return period.(3)Using the method of theoretical calculation,this paper analyzes the benefits of clean and seepage storage of roof rainwater source.The analysis results show taking all building roofs of a university as an example,the total economic benefits of the source clean and seepage storage devices of the roof rainwater can be more than 28.97 million yuan in their service life,and it can also bring good environmental and social benefits.The research on roof rainwater source clean and seepage storage technology in this paper is in line with the development trend of sponge city construction innovation.It is an intelligent decentralized rainwater source control and utilization regulation technology,which is of positive significance to promote the construction of sponge city.Figure[38]table[8]reference[103]...