Roofmeadow’s plan, well executed this first time around, is to take existing bus stops and turn them green. The 60 square foot bus stop green roof at 15th and Market was based off of Roofmeadow’s idea to create a prefabricated kit that can be used to install a green roof on any standard bus shelter in Philadelphia and is meant to help promote PWD’s efforts to raise awareness around urban storm water issues. Any future replications of this first design will be paid for not by the city but by funds from advertising on the side of the bus shelter where the green roof has been installed.
The green space has a standard depth of 3 inches and is planted with mostly pre-grown mats of Sedum — a pretty standard succulent that once rooted, requires little care — along with a few blooming Sweet Williams planted in corners of the roof where the depth reaches 6 inches. The roof will need to be watered throughout its first year to help the plants take root but afterward will need little care to thrive. The roots of the plants will reach down into a lightweight moisture retention layer that will help keep the plants watered and cool during hot summer months.
Installing green roofs in urban areas — like Mayor Bloomberg is planning to do in New York City — can significantly help with storm water runoff issues that can cause extensive pollution when old city water systems aren’t equipped to handle runoff caused by non-absorptive city surfaces — like concrete, asphalt and rooftops. Adding green spaces, especially green roofs, can help absorb that water and stop it from carrying pollution into local waterways and sewage systems. Though this tiny green roof at the corner of 15th and Market will only absorb a small amount of water, imagine the water retention possibilities if all of Philadelphia’s 550 planned bus stops, with their powers combined, had green spaces overhead.