Research On The Optimization Of Urban Waterlogging Prevention Technology Based On The Concept Of Low-impact Development

In recent decades,rapid promotion of economic industry in China has led to the rapid development of urban construction.The urbanization rate has increased by a large proportion.The farmland,wasteland and even green areas have been continuously reduced.The ecological environment has been persecuted,which has changed the process of rainfall production and convergence.Frequent extreme disaster weathers have caused urban drainage to be overwhelmed and the risk of internal locusts has increased.The core of the low-impact development concept is a green and advanced rainwater resource management,which is dedicated to solving urban floods,stormwater runoff pollution,and water reuse.This paper analyzes the internal control technology under the low-impact development concept,and divides the “inside points” within the scope of the Yule Lake area in Nanchang to different levels based on the risk level of the intrinsic risk,and rationally selects the Low Impact Development(LID)facility.Targetedly solve the "inside point" of the catchment area,and improve the drainage flood control standard by constructing a "serial-parallel" arrangement between the LIDs and the addition of the storage tank.The main research results are as follows:(1)Based on the characteristics and causes of the disasters in Nanchang,the classification of the risk level of the inland capital of Nanchang is divided into the common intrinsic points,the easy internal points and the extremely easy internal points;and the low impact development concept The efficacy and applicability of the internal control technology are compared.The series,parallel and series-parallel hybrid arrangements of the LID facilities are introduced separately,and the advantages,disadvantages and applicable conditions of various arrangements are summarized.(2)Taking the Yule Lake of Nanchang as the research area,the preliminary study of the study area is divided into large,medium and small regional scales and refine the watersheds again.Modeling and analysing the runoff process and pipe channel overload in the traditional situation.Noding overflow situation and summarizing the distribution of defects in each area.According to the situation of internal defects,the conventional-LID arrangement for small-scale areas can directly raise the drainage standard to 10a-20 a,the flood control standard basically meets 50 a,and the drainage standard of the conventional-LID arrangement and simulation for the mesoscale study area is 3a~10a,the anti-mite standard is 10a~20a,so that the optimal arrangement is repeated in series and parallel,and finally the drainage standard is 10a-20 a,the flood control standard is 50 a,and the standard is met;the conventional-LID layout is also carried out for large-scale areas.Simulation analysis,the drainage standard is 3a ~ 10 a,flood control standard 10 a,but the large scale 2 study area can meet 50 a flood control due to the presence of the inner lake.In general,LID is not the same for different scale areas,and small scale > mesoscale > large scale.(3)Finally,based on the different scale divisions and simulation results,the overall research area model is integrated,and the conventional-LID scale arrangement is synchronized,and the SWMM model of traditional development and conventional-LID layout is obtained after refinement,and the drainage water condition is analyzed.Up to 5a,the anti-smashing standard is 10 a,in order to upgrade it to the 50 a flood prevention standard,the conventional-LID layout is optimized,and two optimization schemes of series-parallel-LID and series-parallel-LID+ storage tank are adopted respectively.The drainage is 10 a,the former is 20 a and the latter is 50 a.However,when the 24 h long duration rainstorm simulation is used,both of them can meet the 50 a rainstorm and flood control,but the storage pool is added from the perspective of economic cost.It is expensive and not recommended for economically underdeveloped areas.