Each week, we profile a BMP—short for Best Management Practices—to demonstrate how local businesses, organizations and neighbors are helping to keep our streams and rivers clean by managing stormwater on their property.

This time next week, the 2011 CitiesAlive conference—the only conference in North America devoted to the green roof and wall industry—will kick off here in Philadelphia. So there's no better time to showcase the green roof atop the PECO building at 23rd and Market streets in Center City. At 45,000 square feet, it's the largest urban green roof installation on an existing building in Pennsylvania. The roof captures 60-70% of the estimated 1.5 million gallons of runoff from the building annually, and the vegetation consists mainly of hardy sedum varieties.

For more details, photos and a video about the PECO green roof, check out the Temple-Villanova Sustainable Stormwater Initiative project page.