Green City, Clean Waters: Philadelphia's 21st Century Green Stormwater Infrastructure Program

Summary

Hundreds of historic cities like Philadelphia experience combined sewer overflows during heavy rainstorms. Philadelphia Mayor Michael Nutter gave the green light to explore reverting from "gray," or traditional stormwater management infrastructure, to "green" or sustainable infrastructure that mimics the natural water cycle.

In 2011, Philadelphia reached an agreement with the Pennsylvania Department of Environmental Protection and the U.S. EPA to explore a largely green stormwater management infrastructure plan to reduce sewage overflows. As a result, an ambitious and comprehensive attempt to overhaul stormwater infrastructure was developed.

Green City, Clean Waters (GCCW) has not only made Philadelphia the first city in the U.S. to meet both state and federal water quality mandates through green interventions, but it will also save the city an estimated $6.5 billion in construction costs over building new pipes.

Process

GCCW is a unique plan, relying almost entirely on green stormwater infrastructure (GSI) systems that capture rainwater, use it to irrigate trees and plants, and then recycle it back into the groundwater to prevent sewage overflows. The plan includes technical analyses; engineering models showing how green infrastructure can be used to address water quality issues; a cost-saving analysis; and a social impact analysis detailing long-term economic, environmental, and social benefits.

GCCW charts a 25-year course of green stormwater infrastructure development to manage runoff from over 9,000 acres of impervious surface and reduce sewage overflow pollution by 85 percent.

The Philadelphia Water Department's greatest challenge has been developing a model for sustainable infrastructure while simultaneously implementing the actual program. No other city has ever developed as comprehensive a green stormwater management plan as Philadelphia.

While PWD is tasked with installing green infrastructure to manage the runoff from a large area of city surfaces, the water utility does not have access to land other than public streets. Therefore, building public and private partnerships has been critical. Finding a way to pay for unique green infrastructure partnership projects within the public utility finance code has also proved challenging. Additionally, there has been a steep learning curve for the green design services market, and implementation costs have been high.

PWD is addressing these issues by educating its contractors, encouraging innovation via design competitions, seeking cost shares via capital alignment, and exploring alternative financing mechanisms.

Mayor Michael Nutter, PWD Commissioner Howard Neukrug, and EPA Region 3 Water Protection Division Director John Capacasa test the pervious concrete at a PWD employee parking lot, a testing ground for six different permeable pavement materials. Photo by Louis Cook, PWD

Engagement

The success of green infrastructure implementation relies on support and participation from the public. Philadelphia took great measures to ensure that it understood public and special interest groups' opinions about green infrastructure throughout the planning and implementation process. GCCW is the direct result of widespread public support for a more livable, sustainable community.

Residents of all income levels were encouraged to help identify green infrastructure opportunities in their neighborhoods. PWD also provides homeowners with free rain barrels and homeowner grants for the development of rain gardens, downspout planters, and de-paving projects. More than 3,000 rain barrels have been installed and 150 grants have already been awarded.

Recognizing that the success of GCCW hinged on buy-in from community and city partners, PWD has teamed up with the Philadelphia Streets Department, Parks and Recreation, Department of Public Property, the school district, and the city planning commission to identify opportunities for stormwater management in the capital and transportation projects as well as to renovate parks and playgrounds, create new community green spaces, and develop green schoolyards.

A new segment of the Central Delaware River Waterfront which will eventually link to the East Coast Greenway, the Penn Street Trail sets a model for waterfront development as a natural buffer. The trail features green stormwater infrastructure in the form of landscaping along the greenway to manage runoff from adjacent streets. Photo by Jared Brey, PlanPhilly.

Results

The GCCW program is in its fourth year of implementation and is already changing the face of the city and greatly expanding the role of the traditional public utility. Since its adoption, the city has completed 113 GSI projects with 200 more in design or under construction.

PWD also provides technical and financial assistance to existing private property owners to retrofit their sites with green infrastructure and reduce their stormwater fees. To date, PWD has reviewed more than 450 private development projects and provided $14 million in grant funds to 37 retrofit projects on industrial properties, universities, churches, and other sites.

Recently, Philadelphia released two manuals: the Green Stormwater Infrastructure Maintenance Manual to provide specifications for proper green infrastructure maintenance and the Green Streets Design Manual to guide developers in Philadelphia and other cities in the design and construction of green streets.