Study On The Impact Of Sponge City Construction On Urban Rainwater Interception And Utilization In Xi'an

The fundamental purpose of sponge city construction is to prevent and control urban rainwater and flood disasters and improve the level of rainwater resource utilization,including the form of optimization of urban pipeline network,construction of water storage facilities,low-impact sponge city construction and so on.Sponge city construction is not only an important means of urban rainwater management,but also an inevitable trend of the future development of modern urban construction.From the perspective of the influence of sponge city construction on rainwater interception and rainwater reuse rate,this paper chooses roof greening plant allocation,roof greening planting structure layer design,rainwater reuse technology and regional comprehensive management as the research contents,and takes how to improve urban rainwater and flood management ability as the research purpose,carries out the influence of sponge city planning on urban rainwater resource utilization level.Research.The main conclusions and results are as follows:1.Applying the weighted evaluation method to the screening of roof greening plants in Xi'an,19 suitable plants were selected and classified into suitable roof greening allocation by scoring and evaluating 27 common greening plants in Xi'an.Based on the simple roof greening configuration with the weakest runoff control ability,the interception rate of vegetation rainfall at saturation of roof greening design in Xi'an City was estimated to be0.9(4)by using the residential land proportion map and the net density control standard of residential buildings.2.The physical and chemical properties of five kinds of plant matrix formulas were analyzed and compared.Sample c(peat soil+sawdust+microbial organic fertilizer+perlite,volume ratio 5:3:1:1)was determined to be the most suitable matrix formula for roof module greening in Xi'an.Based on the optimal matrix combined with module greening,the capacity of roof greening module to reduce rainwater is estimated to be 81.7 kg/m~2.3.Taking a school in the study area as an example,the rainwater reuse system is designed.Through the analysis and design of water balance table,it is calculated that the rainwater collection and utilization rate of the rainwater reuse system can reach more than95(4),and the 95(4)of rainwater can meet 57.87%of the water consumption of outdoor greening,road flushing and landscape water recharge in the school.4.Based on the harnessing data of the Happy River Basin,by calculating the amount of the six sub-projects of the harnessing project in the region,i.e.the up-regulation reservoir,the underground regulation reservoir,the optimization of the rainwater pipeline network,the reconstruction of the reservoir point,the expansion of the river channel and the construction of the low-impact sponge city,the corresponding amount of rainwater regulation and storage for each group of projects is calculated,and the total amount of rainwater regulation and storage for the harnessing project in the region It is 421.3 million m~3,which is much larger than the required storage capacity of 254.4 million m~3,thus increasing the storage capacity of rainwater.