Philadelphia Turns Massive Stormwater Runoff Problem Into Economic Boost

(Photo: Closeup from a Philadelphia green infrastructure tour. Credit: Leonel Ponce, Flickr Creative Commons)

by | Mar 30, 2018

Philadelphia stormwater greened acres

(Photo: Closeup from a Philadelphia green infrastructure tour. Credit: Leonel Ponce, Flickr Creative Commons)

Philadelphia has long struggled with stormwater that sends massive amounts of polluted runoff into nearby rivers. Rather than spending nearly $10 billion it didn’t have on a new 30-mile-long tunnel, the city is investing a fraction of that on thousands of “green” infrastructure sites.

And the strategy is paying off, Bruce Stutz reports in Yale Environment 360.

The city is seven years into a 25-year project designed to reduce 85% Philadelphia’s combined sewer overflows by 85% under an agreement with the EPA, Stutz explained. “The city is investing an estimated $2.4 billion in public funds — to be augmented by large expenditures from the private sector — to create a citywide mosaic of green stormwater infrastructure.”

Called Green City, Clean Waters, the city’s project recreates living landscapes that once slowed, filtered, and consumed rainfall. Ranging from downspout planters to complex bioretention swales that have drains running underneath them, the green infrastructure sites are intended to work in tandem with rain gardens, tree trenches, green roofs, and urban wetlands, Stutz reported.

“In the end, Philadelphia hopes by the mid-2030s to create the largest green stormwater infrastructure in the United States,” he wrote.

Progress toward the goal is measured by “greened acres” that manage stormwater runoff. So far, Philadelphia has built around 1,100 greened acres and has plans for another 1,300 over the next three years, according to Stutz. “[T]he green infrastructure already is exceeding targets for stormwater overflow reduction, cutting that volume by 1.7 billion gallons — nearly three times the original projection.”

A Break on Stormwater Fees

Each public greened acre can cost in the ballpark of $250,000 to $300,000. However, most of the greened acres completed in the city by the end of last year were on private property, encouraged by redevelopment or incentives.

Stutz noted that Cardone Industries, a local auto parts manufacturer, used a Stormwater Management Incentives Program grant to plant swales and detention basins on its 69-acre property for managing 5 million gallons of runoff annually. The manufacturer in turn receives a $250,000 yearly break on stormwater fees.

Increasingly, companies see rainwater harvesting as a way to address their water and energy challenges. Zachary Popkin, program manager for the Energy Coordinating Agency (ECA) in Philadelphia, pointed out on the Forester Network how commercial property owners are beginning to realize just how much stormwater fees can cost them. The ECA’s own system includes a 3,000-gallon cistern for the toilets and urinals in their training center, and to wash their vehicle fleet.

Fortunately for commercial property owners, Stutz reported that the wider adoption of green infrastructure is driving costs down. “The city is working now to standardize the construction of green infrastructure and monitor its effectiveness,” he added.

Marc Cammarata, the Philadelphia Water Department’s deputy commissioner of planning and environmental services, told Stutz that the greened acres are bringing environmental investment to often marginalized neighborhoods. The journalist also cited a study by the Sustainable Business Network projecting a $3.1 billion economic impact over the first 25 years of Green City, Clean Waters.

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