Toronto's Wetlands: The Humber Marshes


South Humber Park

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Toronto’s watersheds all share a basic form, as their headwaters arise along the Oak Ridges moraine to the north, a 12,000 year old remnant of the last ice age that is the source of 65 major streams or rivers. These waterways flow south over the Lake Iroquois bluff towards Lake Ontario, creating wetlands in the lower regions. The original character of these rivers and extensive wetlands has been severely obscured by agricultural and urban development. It is estimated that 90 percent of Toronto’s wetlands have been lost to infilling and dredging since the time of European settlement.

One of the most important wetlands in Toronto is along the Lower Humber River floodplain, with its marshes and swamps, extending from the river mouth to Dundas Street. In pre-European times the marsh’s wide range of plants, fish, waterfowl and mammals made it a vital seasonal hunting, fishing, and gathering site for First Nations.

Humber Marshes, c. 1900s (public domain).

Although significantly reduced in area, the remnants of the Humber Marsh have stubbornly survived pollution, landfill, residential development, a golf course (now gone), and the construction of the adjacent Humber Wastewater Treatment Plant. The catastrophic flooding that followed the torrents of Hurricane Hazel in 1954 dramatically illustrated the need to stop the destruction of the Humber Marshes. Much of the floodplain was taken into public ownership and is being nurtured as parkland today.   In recognition of the Humber River's rich human history, it was declared a "Canadian Heritage River" in 1999.

By James Marsh

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Humber Marshes in autumn, c. 2009 (photo by Lance Gleich). View the image gallery