Authors: Jing Ren, Elin Knutsdottir, O. Grant Clark
Published in: CSBE-SCGAB Technical Conferences » 5th CIGR and AGM Quebec City 2021 » Regular Sessions
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Description: Urbanization increases the impermeable surface area in cities, leading to changes in hydrological processes. Low impact development (LID) is an urban planning approach in which the natural hydrology is retained as much as possible, to preserve or enhance diverse ecological functions. The urban forest can be operationalized as part of LID, but a lack of information about the effectiveness of this approach impedes its adoption. The use of tree pits was researched by McGill University in collaboration with the City of Montreal to redirect urban runoff away from the sewer system and design the soil mixture within the tree pits to treat the runoff water quality. In this research, the mobility of four prevalent heavy metals (zinc, lead, copper and cadmium) and sodium from de-icing salt were studied. Data from hydrological field studies and soil column experiments allowed us to parameterize HYDRUS 1D to simulate water infiltration and solute transport through the vadose zone of the tree pits. We estimated the response of the system to different soil organic matter content and permeability of the surrounding surfaces. According to the preliminary 2-year simulation results, the heavy metals are effectively immobilized in the tree pit soil, but sodium is readily transported through the soil. Long term simulations of the movement of heavy metals and sodium through the tree pit soil are being conducted. Our results will assist city planners to improve the design of tree pits to efficiently divert stormwater runoff and moderate contaminant concentrations.
Conference name: 5th CIGR International Conference and CSBE-SCGAB AGM 2021, Quebec City,QC, 11-14 May 2021.
Session name: Soil and Water 4 - Soil conservation & Pollution Control
Publication type: Presentation
Language 1: en
Rights: Canadian Society for Bioengineering