TRACK 1, DAY 2
Evaluating Storm Sewer Exfiltration: Hydraulic Efficiency and Water Quality in Tight Soils
Adrienne Sones, City of London and Clare Robinson, Western University
Wednesday, April 1, 2026 | 1:45 p.m. to 2:15 p.m. | Hall A
ABSTRACT
In 2020, the City of London, ON installed a 500 m low-impact development (LID) exfiltration storm sewer as part of an arterial road reconstruction project. The system provides retrofit stormwater controls to an arterial road, to achieve recommended runoff volume control targets established by a Subwatershed Environmental Assessment.
The City of London and Western University collaborated to monitor the system’s hydraulic and hydrogeologic response over a 12-month period including understanding the infiltration quantity and interaction with the groundwater system. The system is installed within low-permeability soils characteristic of southwestern Ontario.
These cost-efficient systems, integrated with conventional stormwater conveyance infrastructure, offer advantages in construction and maintenance. Being located within the municipal right-of-way, these systems can be well suited for municipalities to achieve runoff volume reduction via infiltration.
The monitoring results showed favorable reductions in total runoff volumes and suggested low connectivity between the exfiltration system and surrounding native soils, over the monitoring period. The results suggest infiltrating stormwater is being preferentially transported to and along man-made high permeability zones within the road structure and this likely contributes to the strong performance of the system in reducing runoff volumes despite the tight soils.
The outcome of this study will help guide the City’s implementation of future exfiltration storm sewer works.
ABOUT THE PRESENTERS
Adrienne Sones, City of London
Adrienne Sones is a Stormwater Engineer with the City of London, bringing over 15 years of experience in water resources management. Her work focuses on Municipal Environmental Assessments, creek restoration, subdivision development, and advancing Low Impact Development (LID) stormwater practices within municipal systems. Adrienne is passionate about fostering collaboration and integrating innovative, sustainable solutions to improve watershed health and infrastructure resilience.
Clare Robinson, Western University
Clare Robinson is a Canada Research Chair in Water Quality and Professor in Civil and Environmental Engineering at Western University. Her areas of interest include groundwater-surface water interactions, contaminant fate and urban stormwater systems. She has specific interest in assessing and enhancing the performance of Low Impact Development (LID) stormwater practices including investigating their impact on urban groundwater systems.