雨水花园对雨水径流热污染控制效果试验研究

Immigration of thermal pollution from stormwater runoff via rain garden

雨水花园是海绵城市建设中应用较为广泛的技术措施之一。为研究雨水花园对雨水径流热污染的控制效果和影响因素,以典型构造的雨水花园试验装置为研究对象,采用人工模拟雨水径流的方法,系统研究了降雨过程中雨水花园各构造层的温度变化规律,以及雨水径流温度、降雨强度对热污染控制效果的影响。结果表明:雨水花园可以有效控制雨水径流热污染,当重现期从1 a一遇增大到10 a一遇时,雨水径流温度的削减量从17.4℃减小到10.5℃,热量削减率从32.42%减少到14.54%;当雨水径流温度从22℃升高至35℃时,温度的削减量从6.3℃增加到20.5℃,热量削减率从20.67%增大到32.65%。此外,雨水花园出水温度受填料层温度影响较大,靠近出水口附近的填料层温度越低,雨水花园出水温度越低。因此,降雨强度越小、填料层温度越低、雨水径流温度越高时,雨水花园对雨水径流热污染的控制效果越显著。

Rain garden is one of the more widely used measures in the construction of sponge cities.In order to study the control effect and influencing factors of rain garden on the thermal pollution of stormwater runoff,the rain garden experimental apparatus with typical structure is taken as the research object,and artificial simulation of stormwater runoff is used to systematically study the characteristics of temperature changing of rain garden during the rainfall process,and the impact of stormwater runoff temperature and rainfall intensity on the control effect of thermal pollution.The results show that the rain garden can effectively control the thermal pollution of stormwater runoff,and when the return period increases from 1a to 10a,the reduction value of runoff temperature in rain garden is reduced from 17.4℃to 10.5℃,and the heat reduction rate is reduced from 32.42%to 14.54%.When the temperature of stormwater runoff increases from 22℃to 35℃,the temperature reduction value increases from 6.3℃to 20.5℃,and the heat reduction rate increases from 20.67%to 32.65%.In addition,the effluent temperature of the rain garden is affected by the temperature of the bottom filler layer.The lower the temperature of the media near the outlet,the lower the temperature of effluent.Therefore,the smaller the rainfall intensity,the lower the media temperature and the higher the runoff temperature,the more significant the control effect of the rain garden on the runoff thermal pollution.