Spatial and Temporal Analysis of Hydraulic Conductivity, Snow Depth, and Soil Properties of a Bioretention System

Abstract

Bioretention Cells (BC) are a Low Impact Development technology that provide distributed storm water management near to its source. Most research envisages BC as a black box with ambiguous processes between the input and the output. This thesis aims to consider BCs as heterogeneous systems with physical processes that vary both spatially and temporally. For this study, a 5-year-old BC at Kortright Centre for Conservation in Vaughan, Ontario is used as an investigation area. The following results were observed. D30 and D60 were lower in the central flow path due to sedimentation and suspended solids deposition. Organic content was negatively correlated with bulk density. Ksat in the central pathway region and non-central pathway region showed a mild rise during and a mild decrease respectively during warm winter days possibly due to freeze-thaw action. However, after statistical outliers were identified and removed from the Ksat data, this effect was not observed. iii Acknowledgments First and foremost, I would like to thank my Lord Jesus Christ for his grace and blessings throughout this research. I wholeheartedly thank my research supervisor Dr. Jennifer Drake for offering me the opportunity to carry out research. It would not have been possible to produce this thesis without her support, suggestions, constructive feedback, and professionalism. I would also like to thank Dr. Elodie Passeport for providing many helpful suggestions and for being the second reader. I would like to thank the Sustainable Technologies Evaluation Program (STEP) at the Toronto and Region Conservation Authority (TRCA) for providing the Bioretention Cell and for collaborating with me on this research. I would also like to acknowledge TRCA staff Mark Hummel, Jacob Kloeze, Tim Van Seaters, Christy Graham, and Dean Young for technical support and help with field work. Financial support for this work was provided by NSERC, MITACS and the University of Toronto. I would also like to acknowledge undergraduate interns Alexander Tonelli, Eric Wang, Redwan Baba and Diego Domingo for carrying out data collection during the summers of 2017 and 2018. My sincere thanks go to my colleagues

Trace Organic Contaminant Transfer and Transformation in Bioretention Cells: A Field Tracer Test with Benzotriazole

“…The volume of the bioretention cell was poorly utilized, with a low soil–water interfacial area of 21 m 2 /m 3 (calibrated from the rhodamine WT tracer, KGE = 0.76), high hydraulic conductivity of ∼44 cm/h, a low effective volume, and a poor hydraulic efficiency of 0.13. This poor utilization suggests that there were large dead volumes and an uneven distribution of the inflow inside the bioretention system, which is typical of the undersized systems or poorly designed or maintained bioretention cells.…”

Hydrologic and soil properties of mature bioretention cells in Ontario, Canada

“…Similarly Asleson et al (2009) observed low KSat values near the inlet, but also distributed randomly throughout the cell. Also, in Gnanaraj (2018) study of the KV site also used in this study, KSat was higher in the centerline of flow and lower along the side slopes, but there was no strong correlation between KSat and distance away from the inlet. In a tracer test also at the KV site, only 30% of the soil volume was used (Gu et al In Prep.…”

“…The formulas for converting between the rate of fall (cm/min) and KSat are described in detail in Elrick & Reynolds (1992). Guelph Permeameter measurements were taken in the centerline of flow, and not along the edges or sides of the bioretention systems, as Gnanaraj (2018) showed that this was where the lowest KSat values were measured. All KSat measurements were taken within a single day at a given site, and all sites were visited between May and July 2019, except for KV which had KSat testing performed in July 2017.…”