How it’s Done

By converting unused plots into basins for stormwater, Philadelphia Green affordably helps reduce stormwater runoff while providing the city with attractive green spaces. The process of transforming a vacant, often trash-strewn, lot isn’t too-terribly complicated, but it does require careful planning and the efforts of many.

First, concrete, asphalt, and trash are removed from blighted lots. In some cases, large machinery must be brought in to unearth and dispose large slabs of pavement. Removing the debris allows for maximum infiltration.

Tests are preformed to measure the ground’s ability to retain and absorb rainwater. In most cases, the rain is absorbed over a 24- to 36- hour period. 

Shallow trenches are created to harness the rainfall and allow it to slowly seep into the ground rather than enter the sewers. The aim is to have the space serve as a “natural sponge” of sorts.

Trees, shrubs, and plants are installed on the sites to take up additional water and release it back into the atmosphere. Unlike pipes and storage tanks, the trenches boast the added benefits of cleaner air, improved aesthetics, and serve as a habitat for small wildlife species.