Experimental Study On The Runoff Control Effect Of Modular Lawn With Water Storage Component

Aiming at the characteristics,shortcomings and defects of the existing lawns and green roofs,this paper presented an improved design focusing on modularization and storage space,and choosed and reconfigured the fillers.All these measures,made the modular lawn with water storage component more convenient on the construction and maintenance compared to the prior,and improve the removal effect of the pollutant of rain and the interception rate of the runoff,and laid a good foundation for its application in sponge city construction.The main conclusions of this paper are as follows:?1?The purification effect of the modular lawn with water storage component on high concentration?SS=500mg/L,turbidity=100NTU,COD=150mg/L,NH₄⁺-N=5mg/L,TP=0.8mg/L?and low concentration polluted rainwater?SS=200mg/L,turbidity=100NTU,COD=50mg/L,NH₄⁺-N=3mg/L,TP=0.4mg/L?is better than that of ordinary green space and the modular lawn without water storage component,and the removal effect of various water quality indexes in high concentration polluted rain water is better that in low concentration polluted rain water.The highest removal rates of COD_Cr,ammonia nitrogen,TP,SS and turbidity in high concentration polluted rain water from the modular lawn with water storage component were up to 78.06%,75.49%,87.81%,97.98%and 93.68%and the highest removal rates of COD_Cr,ammonia nitrogen,TP,SS and turbidity in low concentration polluted rain water can reach 48.13%,66.64%,63.08%,85.98%and 73.81%.It can effectively reduce the pollution of rainwater runoff in practical engineering.?2?At the same time,for the modular lawn with water storage component and the modular lawn without water storage component,quartz sand is more suitable for removing COD_Cr,SS and turbidity in rainwater,while loess has better performance in removing ammonia nitrogen and TP,and in the case of the same type and thickness of the underfill,the upper layer?3mm quartz sand thickness 5cm is more beneficial to the removal of pollutants than that of 2.5cm.?3?In the light of the plant growth status,although the growth of Ryegrass in modular lawn with water storage component is not as good as that in ordinary green space and the modular lawn without water storage component,and the mortality is a bit high,it's 3.4 times more than the modular lawn without water storage component.On the control effect of interception rate,the interception rate of the modular lawn with water storage component to the rainfall is obviously better than that of ordinary green space and the modular lawn without water storage component.When the total rainfall is greater than 56L/h,the modular lawn with water storage component will start to generate the flow.When the total rainfall reaches 196.1L/h,the interception rate can also be stabilized at about 30%,which is far higher than the 3.92%retention rate of the modular lawn without water storage component,and is also higher than the rejection rate of 9.39%for the ordinary green space,it shows An excellent interception effect of small rainfall and good interception effect for heavy rainfall.?4?Accroding to a total of 20 years of rainfall data in the city of Xi'an in1995²014,the average annual rainfall interception of the modular lawn with water storage component can be 0.42m³/m²,an average of 46.84%of lawn sprinkled water can be saved on average annually.