Engineering and Design Services for a Green Infrastructure Network in a Pilot Sewershed

Franco Montalto: Civil, Architectural & Environmental Engineering

Sponsored by the Philadelphia Water Department, this project envisions using empty plots of land to form a sustainable network of stormwater management devices that could also serve as recreational amenities and community development generators. It unites urban planning and aesthetic concepts with a new water resource engineering modeling tool to address urban land vacancy as an opportunity to create long-term solutions for the 40,000 vacant properties in Philadelphia.

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Focusing on the CSOsheds (combined sewer overflow) containing Philadelphia's Point Breeze neighborhood, and in particular the Point Breeze Avenue retail corridor, the Drexel University along with project partners Waterwork Design Team based at Charles Loomis Chariss McAfee, Architects are creating a green infrastructure master planning approach that addresses community revitalization, ecological restoration, and stormwater reduction. This approach will serve as a demonstration of how creative and innovative green infrastructure retrofits can be used to meet PWD's stormwater management imperatives to maximize runoff reduction and stormwater utility credits for property owners and to minimize site disruption and construction and operation costs. In addition to these goals, the project team is likewise articulating a strategy to maximize community development opportunities (as articulated by the community members themselves and to maximize ecological improvement opportunities.

The project combines investigations into physical, historical, code-related, legal/regulatory, spatial, urban design, and other existing site factors to estimate the stormwater, community, and ecological benefits that could result from a full build-out of all possible green infrastructure retrofit opportunities—including vegetated traffic islands, green rooftops, porous pavements, rain barrels, public gardens, and the like—in the study site.

The work encompasses three broad tasks:

  • A community needs assessment and local data gathering
  • Development of a new modeling tool for simulating the parcel and aggregate benefits of green infrastructure retrofits
  • Conceptual design of sample green infrastructure retrofits
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Within those tasks, the team is identifying where and how specific green infrastructure technologies can be appropriately and effectively retrofit into an urban watershed—within parameters that are generated by and acceptable to neighborhood residents—and is evaluating the multiple impacts that these retrofits would have on reducing combined sewer overflows, on the local community, and on local ecological systems. Existing hydrologic and hydraulic models have been used to estimate the stormwater benefits of green infrastructure implemented on various land parcels, but the associated community and ecological benefits have proven more difficult to evaluate, model, and document. This research represents a new approach for quantifying the multiple benefits of green infrastructure retrofits as they might be phased into Philadelphia neighborhoods through various stormwater, planning, and green infrastructure programs.