Highland Creek

Highland Creek Watershed Greening Strategy

Toronto and Region Conservation Authority (TRCA) has developed a greening strategy that identifies priority greening opportunities within the Highland Creek watershed to support City of Toronto and other partner restoration projects.

The strategy received approval from TRCA’s Board of Directors on September 25, 2020 and is now available to download and view.


The Highland Creek watershed falls almost entirely within the City of Toronto, with just a small section located in the City of Markham. It is approximately 102 square kilometres in size — small compared to the other watersheds in the Greater Toronto Area.

Highland Creek at Morningside Park in Autumn

Highland Creek Watershed Features

Highland Creek is the most urbanized urbanized watershed in the Toronto region. Just 6% of its total area is forested. Despite this, the Highland Creek watershed boasts approximately 54 kilometres of trails. Its remnant forests, wetlands, and meadows offer great escapes in nature.


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 that 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 paved, impermeable surfaces, such as roads, parking lots, and roofs.

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.

Stormwater management is key to the health of a highly urbanized watershed like Highland Creek
Stormwater management is key to the health of a highly urbanized watershed like Highland Creek.

The Highland Creek watershed has very little stormwater control for improving water quality. Approximately 9% of the watershed has stormwater management controls. The highest level of controls can be found in the upper portions of the watershed (in the City of Markham) and within the Centennial Creek subwatershed (City of Toronto).


Today, only 11.4% of the landscape in the Highland Creek Watershed remains as natural cover — one of the lowest percentages of the watershed in TRCA’s jurisdiction.

The remaining natural cover is unevenly distributed across the watershed, found mostly in the lower reaches. These areas are associated with steep ravines in the east and tributaries in the west. Only 15% of the remaining natural cover is located within the heavily urbanized area north of Highway 401.

The loss and unevenness of natural cover across the watershed results in:

  • Reduced opportunities to support species populations
  • Poor links between habitats (i.e., between the lower and upper reaches of the watershed and between neighboring watersheds)
  • Uneven provision of ecosystem services to residents

Highland Creek has the lowest percentage of natural cover of any watershed in the jurisdiction of TRCA

Current Projects & Initiatives


Watershed Report Cards

Watershed report cards provide an evaluation of watershed health and an ongoing call to action.

Neighbourhood Greening Plans

TRCA, working with local residents, developed a series of Neighbourhood Greening Plans for the Morningside Park, Milliken Park, and Cedarbrook Park communities. These plans identify opportunities to better manage stormwater, expand and reconnect isolated patches of natural habitat, and restore the urban forest.