Assessing the Impacts of High Rate Biofiltration on Parking Lot Runoff Quantity and Quality in Columbus, Ohio

Abstract Submission: Urbanization results in an increase of total impervious land cover, ultimately producing greater quantities of runoff. Grey infrastructure, such as pipes and catch basins, dominate these urban landscapes and contribute to the transport of pollutants from runoff into local waterways. Bioretention is a common form of green infrastructure that mimics natural, pervious systems with the use of vegetation and media to mitigate both runoff quality and quantity issues in urban watersheds. High rate biofiltration (HRBF), an alternative to bioretention, has a relatively higher hydraulic conductivity, allowing for reduced filter surface area while still providing water quality improvement. HRBF systems are ideal for parking lots, which are substantial contributors to pollutant generation due to vehicular and pavement wear as well as winter salting. In this study, three HRBF systems, designed in collaboration with Advanced Drainage Systems (ADS), were installed in parking lots on Ohio State University’s campus in Columbus, Ohio. One system was planted with a tree, while two remain unplanted; media type and depth are consistent between treatments. Flumes, weirs, and automated samplers are being used to quantify runoff hydrology and water quality (including heavy metals, total and dissolved nutrients, and indicator bacteria) immediately upstream and downstream of each HRBF. Internal water level, soil moisture, and conductivity are being used as indicators of water and solute movement through the filters. This study will help define relationships between biofiltration efficiency and engineering design choices, and overall help to improve HRBF design for efficient urban water management.

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