生态植草沟结构参数变化对降雨径流调蓄净化效应的影响

通过对5条不同结构参数的生态植草沟进行模拟降雨径流实验,分析生态植草沟结构参数变化对降雨径流的调蓄效应和污染物净化效应的影响,找出效果最佳的结构参数和相关影响因素。结果表明,5种结构参数的生态植草沟在大雨(12mm/h)和暴雨(24、30mm/h)情况下对降雨径流洪峰的延缓均能超过20min,同时对降雨径流的削减率均能达到20%以上;5种结构参数的生态植草沟中对径流污染物净化效果最佳的结构组合是:20cm种植土+30cm砌块砖+10cm砾石,此结构对总悬浮物(TSS)、化学需氧量(COD)、氨氮(NH+4-N)和总磷(TP)的削减率分别为89.3%、48.0%、72.3%和85.3%;随着砌块砖厚度增加、砾石厚度减少,植草沟对TSS和TP的削减率都增大;随着砾石厚度增加、砌块砖厚度减小,植草沟对COD的削减率增大;砌块砖层和砾石层组合结构的植草沟对氨氮的削减率较高。

Effects of Grass Swales Structure Parameters on Storage and Pollutant Removal of Rainfall Runoff

Five eco grass swales of different structure parameters were tested in simulated rainfall runoff to analyze the storage effects on runoff and pollutant removal effect in eco grass swales,and then the best structure parameters and related factors were found.The results showed that the five grass swales of different structure parameters could delay the peak more than 20min in all the storm(12,4 and 30 mm/h)cases,and reduce the rainfall runoff by more than 20%.The best structure parameters of grass swales to remove pollutant of rainfall runoff is 20cm planting soil,30cm block brick,10cm gravel,which could remove TSS(total suspended solids),COD(chemical oxygen demand),(NH⁺₄-N)(ammonium nitrogen)and TP(total phosphorus)by 89.3%,48.0%,72.3% and 85.3% respectively.The removal rate of TSS and TP would be improved with the increase of the thickness of block brick and decrease of the thickness of gravel.And the removal rate of COD would drop with the increase of the thickness of gravel and the decrease of the thickness of block brick.While the grass swale with a composite structure of block brick and gravel has a higher removal rate of (NH⁺₄-N).