Plant species contribution to bioretention performance under a temperate climate

Henry Beral; Danielle Dagenais; Jacques Brisson; Margit Kõiv-Vainik

doi:10.1016/j.scitotenv.2022.160122

Plant species contribution to bioretention performance under a temperate climate

Sci Total Environ. 2023 Feb 1;858(Pt 3):160122. doi: 10.1016/j.scitotenv.2022.160122. Epub 2022 Nov 9.

Authors

Henry Beral¹, Danielle Dagenais², Jacques Brisson³, Margit Kõiv-Vainik⁴

Affiliations

¹ Institut de recherche en biologie végétale, Département de sciences biologiques, Université de Montréal, 4101 East Sherbrooke St, Montreal, Quebec H1X 2B2, Canada. Electronic address: henry.beral@umontreal.ca.
² École d'urbanisme et d'architecture de paysage, Faculté de l'aménagement, Université de Montréal, 2940, chemin de la Côte-Sainte-Catherine, P.O. Box 6128, Downtown Station, Montréal, Québec H3C 3J7, Canada. Electronic address: danielle.dagenais@umontreal.ca.
³ Institut de recherche en biologie végétale, Département de sciences biologiques, Université de Montréal, 4101 East Sherbrooke St, Montreal, Quebec H1X 2B2, Canada. Electronic address: jacques.brisson@umontreal.ca.
⁴ Institut de recherche en biologie végétale, Département de sciences biologiques, Université de Montréal, 4101 East Sherbrooke St, Montreal, Quebec H1X 2B2, Canada; Institute of Ecology and Earth Sciences, University of Tartu, Vanemuise 46, 51003 Tartu, Estonia. Electronic address: margit.koiv.vainik@ut.ee.

PMID: 36370788
DOI: 10.1016/j.scitotenv.2022.160122

Abstract

Bioretention systems are green infrastructures increasingly used to manage urban stormwater runoff. Plants are an essential component of bioretention, improving water quality and reducing runoff volume and peak flows. However, there is little evidence on how this contribution varies between species, especially in temperate climates with seasonal variations and plant dormancy. The aim of our study was to compare the performance of four plant species for bioretention effectiveness during the growing and dormant periods in a mesocosm study. The species selected (Cornus sericea, Juncus effusus, Iris versicolor, Sesleria autumnalis) are commonly used in bioretention and cover a wide range of biological forms and functional traits.All bioretention mesocosms were effective in reducing water volume, flow and pollutant levels in both of the studied periods. Plants decreased runoff volume and increased contaminant retention by reducing water flow (up to 2.7 times compared to unplanted systems) and increasing water loss through evapotranspiration during the growing period (up to 2.5 times). Plants improved removal of macronutrients, with an average mass removal of 55 % for TN, 81 % for TP and 61 % for K compared to -6 % (release), 61 % and 22 % respectively for the unplanted systems. Except for Sesleria, mass removal of trace elements in planted mesocosms was generally higher than in unplanted ones (up to 8.7 %), regardless of season. Between-species differences in exfiltration rate and improved water quality followed the same order as their evapotranspiration rate and overall size, measured in terms of plant volume, leaf biomass, total leaf area and maximum average root density (Cornus > Juncus > Iris > Sesleria). By increasing evapotranspiration, plants decreased runoff volume and increased contaminant retention. Nutrient removal was partly explained by plant assimilation. Our study confirms the importance of plant species selection for improving water quality and reducing runoff volume during bioretention under a temperate climate.

Keywords: Biofilter; Bioretention; Cold regions; Plant species; Seasonal variation; Stormwater runoff management.