Philadelphia's Green Infrastructure Model: Lessons for Pittsburgh
In This Article
In 2011, the Philadelphia Water Department did something no other major American city had done: it won federal approval for a green-first approach to managing combined sewer overflows. Instead of building massive underground tunnels to store stormwater — the default strategy for most cities under consent decrees — Philadelphia committed to a 25-year plan centered on green infrastructure.
Eight years in, the results are in. And they offer Pittsburgh a roadmap.
Philadelphia's Green City, Clean Waters Program
Philadelphia's Green City, Clean Waters program is a 25-year, $2.4 billion initiative that prioritizes green infrastructure — rain gardens, tree trenches, permeable pavement, green roofs, and stormwater basins — as the primary tool for reducing combined sewer overflows. The goal is to transform the city's relationship with stormwater, treating it as a resource to be managed at the surface rather than a problem to be buried underground.
By 2019, eight years into the program, an independent analysis by Econsult Solutions for the Sustainable Business Network of Greater Philadelphia had already documented measurable reductions in overflow volumes from areas where green infrastructure had been installed.
What the Data Shows
The analysis confirmed several key findings that are directly relevant to Pittsburgh's situation:
- Green infrastructure reduces overflows. Tree trenches, rain gardens, and permeable surfaces capture stormwater before it enters the combined sewer system, reducing the volume that triggers overflows during rain events.
- Benefits are equitably distributed. Green infrastructure projects were disproportionately located in low- to moderate-income neighborhoods, meaning the benefits of clean water investment flowed to communities that needed them most.
- Local economies benefit. Because green projects are smaller and more dispersed than tunnel construction, local businesses could be contracted as vendors, spreading economic impact across the community.
- Additional community benefits accrue. Green infrastructure creates open space, increases tree canopy, improves air quality, and enhances property values — benefits that gray infrastructure simply cannot deliver.
"They were disproportionately located in low- to moderate-income neighborhoods, and seeing that we consider them as beneficial we think that that's a good thing." — Lee Huang, Vice President of Econsult Solutions
Why This Matters for Pittsburgh
Pittsburgh and Philadelphia share the same fundamental problem: combined sewer systems that overflow during wet weather. Both cities are under federal consent decrees. Both face billions of dollars in mandatory infrastructure investment. The difference is in approach.
ALCOSAN's Wet Weather Plan includes green infrastructure, but it is not the priority. The plan is built around gray infrastructure — tunnel construction and treatment plant expansion — with green as a supplement. Approximately $100 million of a $2 billion plan is allocated to green infrastructure through the GROW program.
Philadelphia's experience demonstrates that a green-first approach is not just environmentally preferable — it is technically viable. The tools work. The data is there. What is needed is the political commitment to prioritize green before gray infrastructure commitments lock in a different path.
The Window Is Closing
Brenda Smith, head of the Nine Mile Run Watershed Association and an ALCOSAN board member, identified the critical challenge in 2019: advocates for green infrastructure need to build the evidence base quickly, before tunnel design and construction commitments shift the momentum irreversibly toward gray.
"It's really incumbent on those of us who favor green solutions to, as quickly as possible, get the evidence that they will perform." — Brenda Smith, Nine Mile Run Watershed Association
Philadelphia has already built that evidence. Pittsburgh does not need to start from scratch. We need to learn from Philadelphia's model, adapt it to our own topography and governance structure, and push ALCOSAN to commit to a binding green infrastructure allocation before the tunnel contracts are signed.
What Philadelphia Got Right
Beyond the technology, Philadelphia's success is rooted in several strategic decisions that Pittsburgh should replicate:
- Early federal buy-in. Philadelphia secured EPA approval for a green-first approach before committing to construction, giving the plan regulatory legitimacy.
- Community engagement. The program was designed with input from neighborhood organizations, ensuring projects went where communities wanted them.
- Equity as a design principle. Green projects were intentionally directed toward underserved neighborhoods, not an afterthought.
- Local economic strategy. Small, dispersed projects created contracting opportunities for local and minority-owned businesses.
- Public transparency. Performance data was tracked and shared, building public confidence and political support for continued investment.
The 3RiversProud Proposal
Our Clean Water Plan incorporates these lessons. We call for a minimum 40% green infrastructure allocation, an expanded and restructured GROW program, an equity scoring system for project selection, local hiring requirements, performance monitoring, and a standing community advisory board.
Philadelphia proved that green infrastructure works at scale. Pittsburgh has the opportunity to prove it again — and to do so with an even stronger commitment to equity, local economic impact, and community engagement. The question is not whether we can. The question is whether we will.
Related Reading
The 3RiversProud Clean Water Plan: A Green-First Proposal for Pittsburgh
Nine billion gallons of diluted sewage overflow into Pittsburgh's rivers every year. Our plan charts a different course — one that puts green infrastructure first, invests in neighborhoods, and follows Philadelphia's proven model.
Understanding ALCOSAN's Wet Weather Plan and the Consent Decree
A 2008 consent decree requires ALCOSAN to eliminate sanitary sewer overflows and reduce combined sewer overflows. Here's what's at stake — and why the timeline keeps slipping.