The Novel Application of Electrical Resistivity Tomography for Spatiotemporal Monitoring of Urban Stormwater Bioretention Systems
Abstract
Bioretention systems are an increasingly popular low-impact development (LID) stormwater management approach that are used to reduce the water quantity and quality impacts of urban stormwater. The study investigated the feasibility and benefits of using non-invasive time-lapse electrical resistivity tomography (ERT) to understand the infiltration and soil moisture dynamics within bioretention systems. This was achieved through monitoring two field-scale operational bioretention systems in London, Ontario, Canada. High-resolution two-dimensional time-lapse ERT surveys were first completed during synthetic and natural rain events to assess the viability of time-lapse ERT to monitor soil moisture changes during events. Following this, three-dimensional ERT surveys were conducted during synthetic and natural rain events to provide increased spatial understanding across the entire bioretention system and thus provide new insights into the infiltration and soil moisture dynamics. Overall, this study shows that ERT is a viable method for in situ monitoring of bioretention systems and that soil moisture dynamics in bioretention systems are highly complex and spatially heterogeneous.