Soil infiltration capacity of sunken green space and the effects of water storage on soil physical properties in Beijing

In order to analyze the law of soil water infiltration in the sunken green space, we monitored dynamically the permeation amount of soil moisture in the sunken green space and the average infiltration rate during the water storage process through simulating the influent water load of sunken green space at different rainfall intensities. The effect of collected rainwater runoff in the sunken green space on the soil porosity and bulk density during the process of collecting surrounding rainwater was explored. The results showed that: 1) Soil permeability in the sunken green space would increase with the increased rainstorm intensity at the heaviest rainfall once in 1, 3 and 5 years provided that the soil water contents are under essentially the same condition. 2) At the same intensity of rainstorm, there was no obvious difference in the permeation amount as well as average infiltration rate; the average infiltration rate tended to be larger for the soil with lower bulk density and larger total porosity. 3) With the times of water storage increasing, soil bulk density and total porosity changed greatly: the bulk density increased from 1.33 to 1.65 g/ cm³, while the total porosity dropped from the original 50.06% to 39.18% after the water storage experiment.