Characteristics of water infiltration in urban soils of Nanjing City

By using dual-ring method,this paper measured the water infiltration rate in urban soils under representative land use patterns in Nanjing City,and studied the characteristics of water infiltration in the soils with different compaction degree.The results showed that there was a great difference in the infiltration rate among the soils with different compactness.Soil infiltration rate decreased with increasing bulk density and decreasing porosity,and the water-transport-limiting layer existed in heavily compacted soils resulted in a dramatic decrease of final stabilized infiltration rate.There was a significant linear relationship between the initial and final infiltration rates in the same soil though their absolute values had a great difference.The urban soils in Nanjing City had a wide range of final infiltration rate varied from 1 mm·h-1 to 679 mm·h-1,which was highly related to the soil compactness,structural status,and skeleton grain contents.The decrease of urban soil infiltration rate could induce the increase of runoff and of the probability and intensity of flooding.