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Highland Creek Watershed Issues & Challenges

The Highland Creek watershed is a largely urbanized landscape.  Reducing negative impacts from urban stormwater runoff and restoring natural features are key challenges TRCA, its partners, and residents of the watershed are working to address.  

As one of the most developed watersheds in Toronto region Highland Creek has a high proportion of hard surfaces, such as roads, parking lots and roofs. These surfaces do not allow rain water to be absorbed into the ground, but tend to direct water into the storm sewer system. This process is known as urban runoff. During heavy rainfalls, the high volume and velocity of water can cause impacts such as erosion, flooding and damage to terrestrial habitat. Runoff also carries untreated pollutants - everything from garbage, oil and gas, fertilizers and pesticides - directly into our watercourses. These pollutants reduce the quality of water we use for drinking and recreation. Visit Connect with the Creek to learn how you can take action to address these challenges in the Highland Creek watershed.


Urban Stormwater Management

Urban Storm Water Management

Stormwater management is needed where urbanization limits the amount of rainfall that infiltrates into the ground and increases the amount of rainfall that is collected and discharged to our streams and rivers. This change in the water cycle can lead to increased flooding and erosion, and reduced recharging of aquifers and baseflow in streams.

Good stormwater management attempts to return the water cycle to a more natural state by reducing flows at source and retaining stormwater in ponds to be cleaned up and released at a controlled rate.

The Highland Creek watershed has very little stormwater control for improving water quality. The long term health of this watershed ecosystem will depend, in part, on increasing the amount of stormwater control. Whether on a large, watershed- wide scale, at a local neighbourhood level or through our everyday actions, everyone has a role to play to protect the health of the Highland, through stormwater management.

Toronto and Region Conservation and the City of Toronto are working together to help provide information and resources that will help residents reduce stormwater runoff from their properties. From rain barrels to pervious pavement, check out the Resources or Take Action section for ways you can help Highland Creek.  

For information on watershed-wide projects and plans, including the City of Toronto's Wet Weather Flow Management Master Plan, please visit Projects and Initiatives.


Terrestrial Natural Habitats

Terrestrial Natural Habitat

Loss and Fragmentation of Natural Habitat

Historically, forest scattered with wetland would have dominated the landscape of the Highland Creek watershed. Today, only 11.4% of the landscape remains as natural cover, one of the lowest amounts compared with other watershed's in TRCA's jurisdiction. This remaining natural cover is unevenly distributed across the watershed, with the large majority is found in the lower reaches of Highland Creek, associated with the steep ravines of the east and west tributaries. Only 15% of the remaining natural cover is located within the heavily urbanized area north of Highway 401. The loss and uneven of natural cover across the watershed results in poor link between habitats (particularly between the lower and upper reaches of the Highland Creek watershed and between neighboring watersheds), reduced opportunities to support successful species populations, and uneven provision of ecosystem services to residents.

Poor Quality Habitat Patches

The average quality condition for the habitat patches in the Highland Creek watershed is ranked as poor (L4 rank), which is below the TRCA regional average of fair quality (L3), and is due to the surrounding urban land-use matrix, small and linear patch sizes, and large degree of fragmentation. As with the distribution of natural cover across the watershed, the quality of the natural cover is also unevenly distributed, with the L3 ranked habitat patches located south of Highway 401 in Morningside Park and at mouth of the Highland. Given this, it is not surprising that 10 of the 11 species of regional conservation concern were reported in the lower portions of the Highland Creek.