The marsh scape project
the leslie street spit, tommy thompson park, toronto, ontario, canada
The Leslie Street Spit is a 250-hectare artificial headland made entirely of construction rubble and sediments dredged from Toronto’s harbour. Extending five kilometres into Lake Ontario, the Spit was unexpectantly colonized by nature in the 1970s, a process further amplified by projects engineered by the Toronto Region and Conservation Authority (TRCA). Now known as Tommy Thompson Park, the Spit is an important Canadian showcase for urban wetlands creation. Seventy-three bird species breed there, including North America’s largest population of double-crested cormorants, whose nests numbered 14,515 in 2018.
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The engineering and management of wetlands on the Spit has been a long-term priority of TRCA. It created wetlands in two confined disposal facilities (CDFs) in which contaminated dredged sediments were dumped over the years, beginning with a 7.7-hectare marsh in Cell 1 in 2003. After capping the sediments to prevent the embedded toxic contaminants from leaching into the future wetland, a variety of innovative techniques were used to facilitate growth of aquatic plant communities and habitats for fish, reptiles, and mammals. These techniques proved successful and thus were deployed in Cell 2, whose marsh now evolves.
© Toronto and Region Conservation Authority
Apart from invasive species like Common Reed (Phragmites) and carp, a key risk to the Spit is extreme weather in the Great Lakes, a likely result of climate change. Flooding of shoreline areas during extreme storms inundates cottonwood and birch woodlands. The flooding also erodes the Outer Harbour shoreline where additional wetlands have been created and are in a fragile stage of growth. However, the TRCA continues to innovate methods for dealing with such challenges. The Spit has become a learning platform for creating wetlands as urban green infrastructure.
Visit and donate: Since 1973, Toronto and Region Conservation Authority (TRCA) has been the agent for development and management of this “accidental wilderness.”
https://tommythompsonpark.ca/donate/
The Friends of the Spit is a non-partisan advocacy group founded in 1977 to keep the Leslie Street Spit as a public urban wilderness.
