Bioretention Cells in Urban Stormwater Management: An Integrative Framework for Hydrologic, Hydraulic, and Water Quality Performance Assessment

Bioretention cells (BRCs) are widely adopted as sustainable, low‐impact development solutions for managing urban stormwater and improving load reduction. Notwithstanding extensive research and widespread implementation, an understanding of the optimal design, effectiveness, and placement strategies for BRCs remains limited. This Ph.D. dissertation addresses these gaps with a thorough investigation comprising three research chapters: a systematic review of existing BRC studies, an evaluation of improved BRC design using a multi‐criteria decision‐making framework, and a full‐scale assessment of a compact BRC system. The systematic analysis examined 114 studies, including field measurements, laboratory experiments, and numerical modelling studies, to synthesise and evaluate the performance of BRCs across a range of designs and site conditions, highlighting significant variability in key indicators, such as runoff volume reduction, peak flow mitigation, and constituent load reduction. This chapter highlights that the variability in performance can stem, sometimes to a significant extent, from a BRC design configuration and site-specific conditions. The analysis illustrates that BRC design improves the functionality of the anthropogenic hydrologic cycle and facilitates load reduction. However, the systematic analysis also highlights critical research gaps, including limited evaluation of BRC effectiveness beyond the site scale and lack of reliable, standardized models to predict long-term performance under highly variable urban conditions. The second research chapter focused on improving BRC design and placement within urban residential settings, building on the insights from systematic analysis presented in chapter 2. Chapter 3 investigated how effectively BRCs perform when implemented across urban residential settings and examined their response under varying rainfall intensities, imperviousness degree, and different BRC configuration settings. For this purpose, an analytic hierarchy process (AHP) was employed within a multi‐criteria decision‐making (MCDM) framework to identify the suitable spatial footprint for BRCs. The analysis considered five key criteria—hydrologic metrics (volume reduction and peak flow reduction), hydraulic metrics (node flooding reduction and network stress reduction), and total cost—to determine BRCs’ footprint and spatial distribution that balance technical performance with economic considerations. This integrated approach contributes to practical design guidelines for urban planners aiming to increase stormwater management benefits while reducing land use and cost. The third research chapter involved a full‐scale evaluation of the proprietary compact bioretention system. Conventional BRCs often require substantial land area, making them impractical in densely populated urban environments. In contrast, the compact BRCs offers the potential for effective urban stormwater management in space-constrained settings. However, further validation is needed to better characterize performance under site-specific conditions, particularly by linking laboratory-determined hydraulic properties of engineered media with field-based quality and quantity data. This study assessed the hydraulic characteristics of a compact BRC’s engineered media through laboratory testing and integrated these results with field monitoring to implement a calibrated and validated stormwater management model (SWMM) model. The results of laboratory experiments show saturated hydraulic conductivity of 1750 mm/h. The validated SWMM model effectively replicates the outflow dynamics with a Kling–Gupta Efficiency (KGE) average of 0.50, indicating acceptable agreement with observed data. Additionally, the model captures the trends of total suspended solids (TSS) concentrations at the outlet with reasonable consistency across multiple storm events, demonstrating its ability to simulate pollutant transport dynamics under the tested conditions. The results indicates that a calibrated and validated SWMM model of the Filterra can potentially be utilized to evaluate the hydrologic and pollutant removal efficiencies of compact BRCs in urban catchments under rainfall events with intensities up to 60 mm/h and inflow TSS concentrations between 17 and 227 mg/L in urban catchments. While the model shows good agreement with observed data in this context, its applicability beyond this range—particularly across varying catchment scales, BRC configurations, or pollutant loadings—requires further validation. In conclusion, this dissertation contributes to urban stormwater management by developing an integrative methodological framework that addresses some of the issues regarding the design and implementation of BRCs. The approach not only provides robust evidence of the effectiveness of BRCs in facilitating natural hydrologic processes and enhancing water quality but also delivers a valuable decision‐support tool for improving BRC design and placement. Additionally, the dissertation provides a calibrated and validated model of a compact BRC that can be potentially used to evaluate the hydrologic and pollutant removal efficiencies of compact BRCs in urban catchments before installations. These contributions are expected to advance the planning, evaluation, and implementation of bioretention-based solutions for urban stormwater management.