5 minute read
Port Lands
Toronto, Ontario, Canada
Future-proofing a former industrial urban area against flooding. The Port Lands consist of low-lying infill with a legacy of industrial uses, overlying what once was one of the largest wetlands on Lake Ontario. They are bounded to the north by the Keating Channel and the Don River, to the west by the Toronto Inner Harbour, to the east by Ashbridges Bay, and to the south by Lake Ontario and Tommy Thompson Park. The Port Lands are among the highest flood risk areas in Toronto. During an event the size of 1954’s Hurricane Hazel—the flood standard for floodplain management in the Greater Toronto Area—approximately 290 hectares of land are in the floodplain. Providing flood protection for the Port Lands and naturalizing the river mouth have long been objectives of the City of Toronto and were prioritized when the government established Waterfront Toronto in 2001. The multi-award-winning Port Lands Flood Protection project transformed and revitalized the underused postindustrial area into a natural asset supporting Toronto’s growth and economic competitiveness, creating a new mouth for the Don River and two new urban islands with associated municipal infrastructure. The new mouth’s multiple outlets will provide expanded waterfront access while creating natural habitats that provide social and environmental benefits locally and regionally.
Article Cover: An aerial view of the Port Lands Flood Protection project (looking east). (Photo by Waterfront Toronto)
Producing Efficiencies
The project undertook studies to characterize soil conditions and develop a reuse strategy for most of the excavated soils, reducing placement costs and minimizing the volume of contaminated soil requiring maintenance. Local river-mouth area surveys were conducted to inform the design for the new naturalized mouth of the Don River. Bioengineered bank protection measures stabilize the riverbanks while providing wildlife habitat. The constructed wetlands emulate abandoned oxbow channels and were reinforced with preventative carp and flood gates. These passive and active management features in an otherwise “static” river system ensure the longterm functionality of its design.
Using Natural Processes
Land farming of soils by optimizing moisture content, aeration, and nutrient addition reduced contaminant levels to ranges that permit reuse within the project. To ensure that flowing ice does not destroy the new river channel during significant winter-thaw flood events, an ice management area has been reinforced with armor stone. Various complex flow adjustments will trigger enhanced sediment deposition upstream of the new river system. Subsequently, dredging activities will move north of the bridge at the newly established Sediment and Debris Management Area. This will reduce sediment deposition downstream in the new channel and the frequency and extent of dredging required.
Broadening Benefits
The project has the potential to deliver wide economic benefits, including billions of dollars in value to the Canadian economy as well as in tax revenues to all orders of government and tens of thousands of person-years of employment. Pulling 240 hectares of underused land out of the floodplain unlocks a prime area that will allow Toronto to grow sustainably and improve its resiliency through one kilometer of new river channel and hectares of new coastal wetland and terrestrial habitat. Social benefits to residents and visitors are a number of new recreational opportunities in the park. The project has received multiple awards recognizing its work and approach.
Promoting Collaboration
The project is the result of a decades-long planning process that launched the City’s Interim Task Force to Bring Back the Don, a citizen-led advisory committee. Their final report in 1991 galvanized support for the Don River as a natural space, ultimately leading to the project currently underway. Public consultation occurred throughout project planning, design, and construction via meetings and events. The project team also regularly consults a Stakeholder Advisory Committee and a Construction Liaison Committee. Close collaboration with indigenous communities, consultants, and designers ensures that the new environment will reflect their interests, history, culture, and traditions.
