The Benefits of Green Infrastructure: How Cities Are Turning Stormwater Problems Into Economic Opportunity
- viridianls
- 2 days ago
- 4 min read
Philadelphia gets about 36-42 inches of rainfall annually, mostly in small storms. Historically, most of this rainfall would seep into the ground, supporting native ecosystems and replenishing groundwater. Today, as a result of too much construction, too much pavement, and too little concern for green space, 33 inches of annual rainfall runs into our streams and sewers.
So what? You might be asking. So…the smallest storms cause streets to flood and rivers to fill with sewage, doing lasting damage to our physical infrastructure and local ecology. And that’s just the beginning of our problems.
Traditional Infrastructure Can’t Adapt to Climate Change
Part of the cause is Philly's combined sewer overflow (CSO), which uses a single network to carry both stormwater runoff and sewage — spewing sewage into rivers when it's overwhelmed. Much of this traditional “gray” infrastructure was engineered for 20th-century rainfall patterns, but climate change is making these systems obsolete faster than cities can replace them.
This is not just a Philadelphia problem. Hundreds of U.S. cities operate under federal stormwater consent decrees, which are court-enforced agreements requiring measurable reductions in overflow and pollution on a set timeline — or else face steep fines. That pressure is one reason municipalities are turning to green infrastructure: landscape interventions like rain gardens, bioswales, green roofs, and wetlands that keep water in soil instead of pipes. These systems absorb, filter, and slow runoff. They also cost less and deliver benefits that gray infrastructure can't.
Green Infrastructure Saves Cities Money
When Onondaga County faced a federal mandate to reduce sewer overflow and improve water quality in Onondaga Lake, officials started with what they know: build more gray infrastructure. Over the next few years, the costs associated with overhauling their system proved untenable; they needed a strategy to meet compliance without just adding bigger pipes.
In 2008, Onondaga partnered with Viridian and Jacobs to manage rainwater at its source. The program, Save the Rain, set a clear target: divert over 200 million gallons of stormwater from the combined sewer system by 2018. Over the next 10 years, more than 200 Green Infrastructure projects were implemented, including rain gardens, bioswales, wetland and meadow restorations, green roofs, street tree plantings, and re-vegetation efforts.
Onondaga achieved their goals, eliminating more than 206 million gallons of sewage overflow with green infrastructure and doing it $25 million under budget. What's more, the lake is cleaner and has once again become a popular community asset with a boost in events and recreational activity. These projects not only saved the rain but made better places for the people of Onondaga.
Green Infrastructure Spurs Economic & Cultural Development
Vacant lots, underused plazas, degraded streets—these aren't just missed ecological opportunities — they're missed economic ones.
In Pittsburgh’s East Liberty, we worked with East Liberty Development Inc. and the East Liberty Presbyterian Church to transform a monoculture front lawn into a diverse public landscape that gathers people and captures runoff — reducing combined sewer overflow while reintroducing habitat into the neighborhood. Using native plantings and bio-infiltration beds surrounded by new hardscaping and seating elements, this new habitat managed stormwater but also changed how the corridor felt and how people used it. It became a visible signal of investment in the neighborhood that spurred growth across the Penn Avenue Commercial Corridor.
That principle scales. Working with the Urban Redevelopment Authority of Pittsburgh, alongside Perkins Eastman Architects and Jacobs, we designed a plan for the Allegheny Riverfront that restores the hydrologic cycle: introducing a continuous tree canopy and riparian buffers along the river and reimagining a dormant railroad as a green corridor connecting neighborhoods to the water. The plan makes the case that ecological infrastructure is the precondition for economic development along the river.
The outcome is the same whether the scale is a church lawn or a riverfront: stronger public spaces, higher property values, and less long-term spending on systems that only do one thing.
Green Infrastructure Benefits Compound Over Time
Unlike traditional infrastructure, which wears down with age, degrades, and often struggles to support increasing rainfall, green infrastructure only gets better with time. Root systems deepen, and soils become richer, improving water absorption. Green infrastructure makes cities more environmentally resilient—and more pleasant! —by reducing the heat island effect and lowering air conditioning costs, supporting wildlife including pollinators, and cutting carbon dioxide and air pollutants— all things that will have long-term economic payoffs.
But there’s a long-term social change as well: communities often become stewards of these landscapes. We’ve seen this happen at FDU, where an ecological investment in the river landscape is creating civic partnerships and institutional identity. The University, which long treated the river as an obstacle to development, is now embracing it as a catalyst for growth.
As rain falls harder and grey infrastructure grows weaker, the question isn't whether our towns and cities will adapt to more intense storms — the question is how. By wasting millions on infrastructure that only solves one problem temporarily? Or investing in infrastructure that solves several at once, building-in resilience, saving money, sparking growth, and creating more beautiful, diverse, and ecologically sound places.
