Caractérisation de l'impact de cellules de biorétention sur la qualité et la quantité des eaux pluviales à Trois-Rivières, Québec

Urbanization and climate change tend to increase combined sewer overflows. These overflows can lead to surface water contamination and environmental quality degradation. Therefore, the stormwater management in urban areas has become a necessity. Bioretention cells as storm water controls have been implemented on Saint-Maurice Street in Trois-Rivières, Quebec. The main objective of this study is to characterize the impact of these cells on the stormwater quality and quantity in urban areas. For this purpose, the methodology used was divided into two parts. The first was to proceed with sampling and analysis in dry weather, in wet weather and in periods of snowmelt at the field scale. The second part was to use the Storm Water Management Model (SWMM) for modeling bioretention cells using real rainfall and flow data, to assess their performance in terms of reducing runoff volumes and peak flows. Field sampling for experimental monitoring took place in 2019, 2020 and 2021. The results concluded that bioretention cells are overall efficient in terms of flow and pollutant retention. They are able to reduce peak flow by 74.2%, phosphorus from 47.6% to 93.5% and metals from 8.5% to 94.7%. However, the release of nitrogen and organic carbon was observed in most of the tests.