Quantifying the Performance of a GSI Network Individually Versus as a Cumulative Series

Abstract Submission: As a need for green stormwater infrastructure (GSI) increases in urban areas, new designs of rain gardens are emerging in which a series of rain gardens are designed along roadways rather than constructing large stand-alone forms of GSI. The city of Philadelphia and the Pennsylvania Department of Transportation (PennDOT) have constructed a series of rain gardens as part of the PennDOT I-95 Section GIR Reconstruction Project. A newly constructed group of four similar rain gardens (L01-L04) will be used as the focus for this research. The rain gardens are fed with runoff generated on a highway deck located directly above them, therefore there is limited solar exposure and subsequently they are partially vegetated. Ponding data within the basins of each rain garden and at the most downstream node were used to observe the responses of each rain garden individually as well as the cumulative downstream response. It was determined that a wide array of construction and maintenance complications to the sites, ranging from underdrain flow leaks to sediment forebay resuspension, create quantifiable impacts to overall site performance. Being able to quantify the impact of these changes on the maintenance of the site allows for a better understanding of how to create effective maintenance plans for the prolonged success of the GSI. Water surface profiles were generated to visualize the flow within the site from the upstream pipe system to the downstream pipe system as a reaction to storm events. This allows for an increased understanding of not only how much water is in this pipe system, but also how quickly it flows through the series of rain gardens. This work contributes to a larger understanding of how a series of rain gardens interact with one another and the factors contributing to an increased performance of the series as a whole.

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