Last week the Pennsylvania Department of Environmental Protection and the Philadelphia Water Department signed an agreement to officially begin using green stormwater infrastructure to reduce Combined Sewer Overflows to its waterways. Philadelphia Mayor Michael Nutter, speaking at a conference last week, presented the new plan:

The Philadelphia Water Department (PWD) submitted plans for the project to the U.S. Environmental Protection Agency and the Pennsylvania Department of Environmental Protection (PADEP) in September, 2009, after vetting the plan with Philadelphia residents. Green City, Clean Waters lays the groundwork for the PWD to build primarily green infrastructure – such as stormwater tree trenches, vegetated bumpouts, porous asphalt, rain gardens, sidewalk planters – over the next 25 years. These projects will transform non-porous surfaces that repel rain into surfaces that allow water to soak through, reducing the amount of environmentally damaging stormwater runoff.