Performance Assessment of Stormwater Management Infrastructures in a Parking Lot near Montreal, Canada

Abstract

Stormwater control measures, including green and gray infrastructures, are increasingly used to enhance the level of sustainability of conventional drainage networks in managing rainfall-induced runoff. This paper studies the water quality and hydrologic performances of some bioretention cells and permeable pavements located in a parking lot in Boucherville (near Montreal), Canada, between July 2020 and November 2021. Because plants play a major role in the performance of green infrastructure, plant survival and growth monitoring were also conducted from June to September 2021. The results showed average runoff volume and average peak flow reductions of 91% and 98%, respectively, while the average delay in peak flow, for the few storm events with outflow, was 6.7 h. The average removal rates (in terms of concentration) for suspended solids, chemical oxygen demand, total phosphorus, and total nitrogen were 96%, 79%, 81%, and 90%, respectively, while there was an average increase in electric conductivity of 14%. The survival rate of trees planted in bioretention cells was 100%. For bushes, survival rates indicated a variation between 54% and 100%, while for perennials, survival rates varied between 0% and 100%. The plants with the least survival rates were Alchemilla mollis when planted at the top, with 0%, Rudbeckia fulgida var. ‘Pot of Gold,’ with 74%, and Salix purpurea ‘Gracilis,’ with 54%.