Conference Agenda

Bioretention cells (BRCs) are commonly used in urban areas to manage stormwater runoff and reduce pressure on drainage systems. However, their performance often differs from design expectations due to construction limitations and site-specific conditions. This study compares water retention in 31 BRCs located in Montreal, Canada, as simulated with the Storm Water Management Model (SWMM) and observed through field data collection. BRCs were selected for analysis based on their impervious-to-permeable (I/P) ratio and physical characteristics. The field data included water level measurements taken by pressure probes and rainfall data provided by the city, used to analyze the hydrological behaviour of the BRCs during the non-freezing season (May to November). Results for four randomly chosen BRCs are presented here. One of these showed close agreement between simulated and observed water retention, with a Nash-Sutcliffe efficiency value of 0.74 and a strong positive correlation. The other three exhibited differences between the modelled and observed data, attributed to discrepancies between the design (modelled) and field-built conditions, as confirmed by field visits. These findings underscore the importance of considering the physical limitations of BRCs in the field and their construction characteristics, such as elevated inlets or poorly directed street slopes, when evaluating their performance.