Over five months, from July to November 2015, researchers from the Sustainable Technologies Evaluation Program (STEP) evaluated the performance of a low impact development (LID) approach to stormwater management retrofitted into Calstone Inc.’s industrial lot in a densely-developed portion of Toronto. Impervious surfaces in developed areas increase the volume and rate of stormwater runoff that can overwhelm aging municipal stormwater infrastructure resulting in flooding and damage to natural and built municipal assets, buildings, and homes. With climate change projected to increase the frequency and intensity of extreme precipitation events, these impacts are likely amplified.
To address these issues, stormwater source controls were implemented on-site, including a rainwater cistern, three soakaway ponds and an infiltration lot. Technical guidance was provided by the Partners in Project Green, a working group of the Toronto and Region Conservation Authority (TRCA). The project was partly funded through grants from Earth Day Canada and the Ontario Ministry of the Environment and Climate Change. Results from monitoring and performance evaluation demonstrated the viability of LID approaches to stormwater source control. The project provides many solutions to stormwater management practices that reduce the vulnerability and increase the resilience of municipal stormwater infrastructure to extreme precipitation events. The understanding gained from evaluating the implementation of such stormwater management systems can be used to inform decisions about future retrofits within similar cold weather contexts across Canada.