Strategies for Addressing Massive Erosion and Slope Instability in Riverine Environments: Insights from Successful Projects in the Greater Toronto Area (Canada)

Join us to discover innovative approaches to mitigating severe erosion and slope instability. As urbanization and climate change heighten these risks, our presentation will highlight two landmark projects by the Toronto and Region Conservation Authority (TRCA) and the City of Mississauga, showcasing pioneering solutions. Gain valuable insights into the design, implementation, and long-term ecological benefits of vegetated reinforced soil structures that not only stabilize slopes but also enhance biodiversity. Learn how these projects effectively safeguarded properties and ecosystems, offering practical lessons and inspiration for your own initiatives. Don't miss this opportunity to enhance your knowledge and skills in managing riverine environments!

Full Abstract: Ravine and valley systems in the Greater Toronto Area (GTA) face severe erosion and slope instability issues, stemming from both anthropogenic and natural factors, such as urbanization and climate change. In some locations these challenges are massive and pose threats to life and property, demanding immediate mitigation strategies. Riverine environments, given their sensitivity, necessitate innovative solutions that not only provide structural stability but also deliver ecological benefits, such as supporting native plants growth and enhancing aquatic, riparian and terrestrial connections.
Toronto and Region Conservation Authority (TRCA) manages risk associated with natural hazards, including erosion and slope instability, as part of its Erosion Risk Management Program (ERMP). Within the GTA, TRCA actively monitors approximately 550 erosion hazard sites and prioritizes the top sites for remedial erosion and slope stabilization works under the ERMP.
I will present and compare two remarkable projects initiated in response to these challenges. The first project, a response to the devastating 2013 storm event in Toronto, addressed a critical slope failure in the Humber River Watershed. This catastrophe resulted in significant property loss and posed long-term risks to over ten homes. The TRCA undertook emergency works in 2015 to stabilize the 12-meter-high slope. Similarly, in 2008, at a separate location along the Etobicoke Creek, the City of Mississauga stabilized a highly eroded 12-meter-high slope.
Both projects implemented vegetated reinforced soil structures, each with unique layouts and systems tailored to local condition. One of the main challenges was to minimize the impact on expensive land-sensitive residential properties and floodplain encroachment. This presentation will delve into the technical design aspects, choice of materials, and the long-term ecological advantages of the final solutions. Additionally, we will provide insights into the current status of these structures, offering valuable lessons and inspiration for future initiatives in riverine environments.