Rag Flats Stormwater Management Techniques


In 2002, Onion Flats collaborated with Minus Studios and Cover to transform the site of a former rag factory into an 11 unit residential urban garden community. The project, completed in 2005, incorporates several sustainable design features, most notably, solar generation capacity to fuel 80 to 100 percent of the units’ demand for electric power.

Due to the high level of impervious cover in the surrounding area, the project team sought to limit runoff from leaving the site as much as possible. Site walkways use concrete turf pavers to increase pervious coverage that will enhance infiltration of runoff. A green roof common area also reduces the amount of impervious cover on the site. The roof features an 8-inch turf system with a drip irrigation system. A 6,000 gallon underground cistern also collects and stores roof runoff for future reuse. Combined, these BMPs significantly reduce the volume of runoff that the site contributes to the local storm sewer system.


County: Philadelphia
Watershed: Delaware River


JD McDonald Plumbing and Heating, Inc.
Minus Studios
Onion Flats


Project cost: $3.5 million
Funding provided by The Reinvestment Fund


Johnny McDonald
Onion Flats
PO Box 14081
Philadelphia, PA 19122

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