单位面积调蓄深度决定了初雨调蓄池的设计容积和截污效果,但仅仅根据规范的推荐取值缺少对后果的量化判断.忽略管道中的沉积和冲刷,分别以单子汇水区和多子汇水区排水系统为例,针对不同下垫面特征和降雨特征,在 SWMM模型中进行多降雨条件模拟,计算得到产流和悬浮固体(SS)的冲刷情况.结果表明,单子汇水区单次降雨初期冲刷主要受污染物积累程度、初雨峰值雨强和初雨总量控制,对多场降雨的初雨SS控制率均很高;多子汇水区系统不同场次降雨 SS削减率可能有明显差异,SS控制率随调蓄深度增加而增加且差异减小,单位面积调蓄深度取 2 mm时 SS控制率已达较高水平,但 4 mm 以上时 SS控制率增速明显减慢;初期雨水调蓄池是否达到了污染控制目标,不应只看是否位于系统的上游,也不只限于根据技术规范的推荐取值,需通过模型计算判断.
Numerical Simulation of Storage Depth per Unit Area of Initial Rainwater Storage Tanks
The storage depth per unit area determines the design volume and interception effect of the initial rain stor-age tank.However,based on the empirical values recommended by technical specifications,there is a lack of quantitative judgment on the consequences of different values.Ignoring sedimentation and flushing in the pipeline,the drainage sys-tems of single and multiple sub-catchment areas were taken as objects.Based on different underlying surface and rainfall characteristics,multiple rainfall conditions were simulated in the SWMM model to calculate the runoff and flush of SS.The initial flush of a single rainfall in the single sub-catchment area is mainly controlled by the pollutants accumulation,the peak rainfall intensity of the initial rainfall,and the total amount of initial rainfall.The SS control rate of the initial rainfall for multiple rainfall events is very high.There may be significant differences in the SS reduction rate of different rainfall events in the multi sub-catchment area system.The SS control rate increases and the difference decreases with the increase of storage depth.When the storage depth is set to 2 mm,the SS control rate has reached a high level,but the growth rate of SS control rate significantly slows down when the storage depth per unit area is above 4 mm.Whether the initial rainwater storage tank has achieved the pollution control goals should not only be determined by whether it is loca-ted upstream of the system,nor limited to the recommended values according to technical specifications.It needs to be determined through model calculation.
initial rainwaterfirst flushrunoff pollutioninitial rainwater storagestorage depth per unit area
NETL
NSTL
万方数据
维普
