Cultivating Stormwater Services with Soil Decompaction and Amendment

Abstract

Stormwater management has traditionally focused on increased runoff from impervious areas (IAs) accompanying urbanization. Far less consideration has been directed to significant changes in the hydrologic characteristics of urban soils that also accompany urban development. Mass grading and standard site development practices disturb and compact urban soil profiles, dramatically reducing infiltration capacity, rooting depths, and the stormwater services provided by urban green spaces. Stormwater services may be purposefully restored using soil decompaction and amendment to rebuild porous permeable organic-rich soil profiles in urban pervious landscapes. In this study, the use of suburban subsoiling (SS) (soil decompaction and compost amendment) for restoring stormwater services was evaluated on a decommissioned highway roadbed and construction staging area that had been designated for afforestation by the Maryland Department of Transportation State Highway Administration. Suburban subsoiling increased the mean infiltration capacity of the site’s disturbed compacted soils by more than an order of magnitude, with dramatic improvements in the bulk density (−28%), organic matter (+82%), and potential rooting depth (+20 to +30 cm) of the restored soil profile. Integrating SS with standard mass grading and land development practices can transform the built environment by cultivating sustainable stormwater services in anthropogenic landscapes.