Philadelphia’s nation-leading commitment to green water infrastructure got a $2 billion shot in the arm Tuesday (April 10) in the form of a new federal partnership that may become a national model.
The “Green City, Clean Waters” agreement between the city and the U.S. Environmental Protection Agency aims to transform many of Philadelphia’s traditional hardened surfaces to green areas, to better manage runoff pollution.
|Porous pavement provides the structural support of conventional pavement but consists of a porous surface and an underground stone reservoir. Porous surfaces include pervious asphalt, pervious concrete and interlocking pavers.|
Polluted stormwater runoff (also known as nonpoint source pollution) is currently the leading cause of water quality problems. The problem occurs when rainfall or snowmelt runs over the ground, picking up a variety of pollutants from animal and septic waste, to oil and toxic chemicals, to fertilizers and insecticides.
Acres of impervious urban pavement and failing sewer systems compound the problem.
From Gray to Green
A key goal of green water infrastructure is to find ways to manage stormwater and wastewater issues without making enormous capital investments in rehabilitating, repairing or replacing aging underground pipes, tanks and other so-called “gray” infrastructure.
By using more pervious pavement, tightening stormwater regulations and pursuing other measures, Philadelphia has become a national urban leader in the green water infrastructure movement.
In November, the Natural Resources Defense Council noted in a report that “green strategies” by Philadelphia and 13 other cities had kept a total of 10 trillion gallons of polluted stormwater out of waterways and overtaxed city sewer systems.
Green City, Clean Waters
Philadelphia’s “Green City, Clean Waters” initiative layers green technologies modeled on natural practices on top of the city’s 3,000-mile sewer network to capture rainwater where it falls, preventing sewer overflows.
The initiative is based on an adaptive management approach designed to identify and maximize green practices that achieve the most efficient and cost-effective environmental goals for the city.
|Philadelphia’s first porous green street—a collaboration of the city’s Water and Streets Departments—allows stormwater to infiltrate the surface and be stored in a stone bed until the soil can absorb it.|
Under the agreement announced Tuesday, EPA will help Philadelphia identify and promote higher-performing green infrastructure designs, convene technical expertise from around the country to advance green designs, and help remove barriers to innovation in the city’s plan.
EPA will also provide research and technical assistance, and help monitor the effectiveness and evaluate the benefits of the program. Plans also call for a green design competition.
“Where other cities are challenged by very expensive commitments for tunnels, tanks and other gray infrastructure, we have worked with the state and the EPA to take this greener, more fiscally prudent approach that will realize multiple benefits,” Philadelphia Mayor Michael Nutter said Tuesday at the announcement of the initiative.
EPA Administrator Lisa P. Jackson, who also attended the event, said Philadelphia “has earned a place as a national and global leader on sustainable innovation and clean water protection.”
She added, “The Green City, Clean Waters Partnership promises to lead the way for communities across the nation, which can use the lessons learned through this long-term project to protect their health, safeguard their waters and boost their economies.”