Research On The Low Impact Development Planning Of Sponge City Based On SUSTAIN

In recent years,with the development of our country's urbanization,the city water security problem attracting widespread attention.In the process of urbanization,cities don't have the water increasing,directly lead to the increase of urban rainfall runoff,formed the city an increase in the number of internal water point,serious can cause urban waterlogging disasters;At the same time,the high-speed urbanization process makes the city scale expanding rapidly,population and car number increase sharply,accumulating a huge mass of human frequent activities in urban surface pollutants,under the effect of leaching of rainfall runoff scouring,into the rivers,the formation of non-point source pollution,urban non-point source pollution is gradually become the main pollution source of urban pollution.Based on the typical area in shenyang as an example,this paper studied the slope roof,flat roof and pavement three kinds of underlying surface rainfall runoff of total suspended particles(TSS),total nitrogen(TN),total phosphorus(TP),chemical oxygen demand(COD)features of four kinds of pollutant emissions.Using the M(V)curve and MFF30(mass first flush),analyzes the different rainfall runoff events of the initial scour the probability of strong erosion,the weak erosion intensity and in.Using the simulation and analysis of urban rainfall runoff control integrated system(SUSTAIN),established in the study area rainfall runoff model,the study area in 2015,rainfall runoff and simulates and analyses the nonpoint source pollution.Finally,according to the different runoff control standard,choose the appropriate measures to low impact development(LID),establish effective functionally and maximize the economic situation,and choose the optimal solutions and meet the requirements of the sponge city construction.The main conclusions of this study are as follows:(1)the road surface runoff pollution levels over roof runoff,TN roof runoff is the main pollutant,TSS,TN and TP is the main road runoff pollutants,TSS than secondary wastewater discharge standard,nitrogen and phosphorus nutrition elements and the strong rainfall and the rain small strong positive correlation,COD is easy to longer duration of rainfall and gradually released into the run-off.Compared with other cities and countries,found that shenyang roof runoff in TSS,TN,TP and COD is less,but there are certain heavy metals pollution;TSS and TP concentration in surface runoff is higher,but the concentration of TN and COD is low.(2)the initial scour phenomenon,more easily in the study area about 50%-90% of rainfall events can generate initial scour phenomenon.The strength of the three kinds of underlying surface occurred early flush is in turn: flat roof roof > > peak road.Rainfall duration and dry period length and the initial flushing effect has a positive correlation,rainfall and rainfall intensity and initial scour first positive correlation,but when the dilution effect is greater than the scouring effect,negative correlation.Heavy metal pollutants initial scour phenomenon occur more easily and TN prone to strong initial scour.(3)LID measures on hydrological processes of rainfall runoff had obvious regulation effect.By comparing the found that the optimized LID measures,in the study area has drastically reduce runoff,runoff of the sponge urban construction standards.Through the green LID measures layer intercept,plants and microbial degradation,soil infiltration function can remove contaminants,different degrees of improvement the quality of runoff water...