Poster 225 – Click on poster below to view presentation from author.
The Ohio State University
Co-Authors: Ryan Winston, Jay Martin
To address the impacts of climate change, urbanization, and total maximum daily load regulations, Green Infrastructure (GI) Stormwater Control Measures (SCMs) are being implemented across the United States. This includes in Columbus, Ohio, where the Blueprint Columbus project will retrofit 25 neighborhoods with GI. In the current work, we set out to elucidate how GI impacts sewershed hydrologic and water quality responses across a wide range of storm characteristics. A total of 251 event mean concentrations and runoff producing storms were utilized in the analysis across three sewersheds retrofitted with GI. An unbalanced factorial ANOVA and Tukey-Kramer post-hoc tests were used to determine significant differences for runoff hydrology and water quality due to rainfall characteristics (on a scale of low-medium-high) and presence or absence of GI SCMs.
Pre-GI, ADP was only a significant driver of TSS, zinc and nitrate concentrations. Higher peak rainfall intensities were positively correlated pre-GI to increased runoff depth, peak flow rate, total suspended solid loads (TSS) and total nitrogen concentrations (TN), but were negatively correlated to zinc concentrations. Installation of GI SCMs significantly mitigated stormwater peak flow rates, heavy metals, TN, total phosphorus, and orthophosphate from storms categorized with medium-high range characteristics. The highest characteristic levels (i.e. >25mm depths) were frequently decreased to equal the lowest rainfall characteristic ranges (i.e. <6.5mm/h peak intensities). This study confirmed rainfall characteristics play a critical role in pollutant transport in stormwater, while acknowledging how GI SCMs can affect those roles. The results further support the impacts that GI has on mitigation of impervious surface hydrology and water quality degradation. Further research into the role GI SCMs have in improving hydrology and water quality could lead to enhancements in the overall resiliency of urban areas.
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