Search

Efforts to retrofit pervious surfaces into urban landscapes are ongoing, yet the in situ infiltration rates of such surfaces have not been adequately studied. Of increasing interest in urban stormwater management is whether the infiltration rates of different permeable surfaces can be reliably estimated based on surface type alone. To this aim, a total of 139 infiltration tests were conducted using a Cornell sprinkle infiltrometer at 39 different sites distributed within New York City and Philadelphia. The results show significant statistical differences among surfaces: urban parks and tree pits without guards have the lowest infiltration rates; vegetated courtyards, tree pits with guards, porous pavers, backyards, and bioretention facilities display moderate infiltration rates; and porous concrete has the highest infiltration rate. The infiltration rates measured for most of the sites are similar or greater than the local design storm, suggesting that minimal rainfall excess would be generated from these surfaces as long as sufficient subsurface storage space is available. [ABSTRACT FROM AUTHOR]