Research papersRestoring hydrologic function in urban landscapes with suburban subsoiling

- Urban land development decouples landscape form and hydrologic function.
- Standard construction practices routinely disturb and compact urban soils.
- Agricultural subsoiling practices were adapted to disturbed compacted urban soils.
- Soil decompaction and amendement restored urban hydrologic function.
- Superior sustainable landscaping reduces stormwater runoff and life-cycle costs.

Dramatic persistent hydrologic changes accompany urban land development, most commonly attributed to increased impervious area and drainage infrastructure. Modern land development and mass grading practices also result in the routine development of urban landscapes with highly disturbed compacted soil profiles. The common predictable result is an urban pervious landscape with greatly diminished infiltration capacity in greenspace that might best be described as grass growing in a thin veneer of topsoil on compacted fill. This paper describes the use of soil decompaction and amendment to restore hydrologic function following the removal of an impervious asphalt playground at a public school in Baltimore, MD, USA. The combination of soil decompaction with deep ripping and compost amendment is referred to as suburban subsoiling, alluding to the adaptation of agricultural subsoiling practices to restore hydrologic function in disturbed compacted urban soils. In this field-scale comparison with standard grading and landscaping practices, suburban subsoiling supported the highest infiltration rates, with the densest turf cover, highest soil organic matter and root zone soil moisture, and the lowest soil bulk density. As a sustainable alternative to traditional grading and topsoiling practices, suburban subsoiling offers a proverbial win-win solution, providing superior landscaping and restored hydrologic services with lower life-cycle costs. Though significantly different than current grading and landscaping practices, suburban subsoiling can be readily integrated in modern land development with only minor incremental changes in standard practices. Suburban subsoiling can transform the built environment through superior sustainable landscaping that restores the hydrologic function of urban pervious landscapes.

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