The Humber River watershed is the largest in Toronto and Region Conservation Authority’s (TRCA) jurisdiction, covering 90,258 ha and home to over one million people. It is also the only Canadian Heritage River in the Greater Toronto Area.
Humber River Watershed Plan
TRCA is in the process of developing a new watershed plan for the Humber River that will use the latest science and data to inform municipal land use and infrastructure planning.
Explore the Watershed
Explore the quick links and map below to learn more about the Humber River watershed:
Cultural Heritage
The Humber River has a rich history, serving as a home for Indigenous peoples and as a vital transportation route known as the Toronto Carrying Place Trail – one of the oldest established transportation routes in Canada.
Select the image below to view the full-sized map.
TRCA, 2023. Humber River watershed Characterization Report.
The Humber River Watershed is covered by:
- Treaty 13 (Toronto Purchase, 1805), Treaty 14 (Head of the Lake Purchase, 1806), and Treaty 19 (Ajetance Purchase, 1818), signed with the Mississaugas of the Credit First Nation (an Anishinaabe First Nation)
- Treaty 18 (Nottawasaga Purchase, 1818), signed with the Anishinaabe Chippewa of Simcoe (including Beausoleil, Georgina Island and Rama First Nations)
- The Williams Treaties, 1923, signed with the Williams Treaties First Nations (the Anishinaabe Chippewa of Simcoe) and the Anishinaabe Mississauga (Michi Saagiig) of the north shore of Lake Ontario (including Alderville, Curve Lake, Hiawatha, and Mississaugas of Scugog Island First Nations)
The lands and waters are also the Traditional Territory of the Haudenosaunee (including the Six Nations of the Grand River), and the Huron-Wendat, and are now home to many diverse First Nations, Inuit, and Métis peoples.
Through work with lands and waters, TRCA appreciates and respects the history and diversity of these lands and is grateful to have the opportunity to work and be in relation with this territory. We are also grateful for the continued work of many First Nations and Indigenous peoples, who are the original and current caretakers of these lands and waters. We humbly acknowledge our responsibility to respect First Nations’ rights and Indigenous perspectives, elevate Indigenous voices, and honour our relationship with First Nations and Indigenous peoples.
Due to its cultural heritage and recreational values, the Humber River is the only Canadian Heritage River in the Greater Toronto Area, and one of 40 across Canada.
View the video below to learn more about the Humber’s Heritage River designation in 1999:
Land Use & Climate
The Humber River watershed is constantly changing as natural and rural areas are turned into urban spaces, such as buildings and parking lots.
If these areas are not built sustainably, it can harm the watershed by impacting water flow, soil conditions, and biodiversity.
As more people move into the watershed, it is important to find ways to support the growing population while also protecting nature and the benefits it provides.
This can be done by creating communities that protect important farmland and natural areas. It can also involve planning urban areas that are walkable, have access to public transit, are energy-efficient, and include stormwater controls and green infrastructure.
KEY CHARACTERISTICS
- AREA: The watershed covers a drainage area of approximately 90,258 hectares, making it the largest in TRCA’s jurisdiction. It includes five subwatersheds: Black Creek, East Humber, Lower Humber, Main Humber, and West Humber.
- POPULATION: 1,012,668 (Census 2024)
- LAND USE: The watershed is approximately 27% urban, 40% rural, and 33% natural as of 2020, but the pressure to develop continues to grow.
- IMPERVIOUS COVER: In the more urbanized subwatersheds (Lower Humber and Black Creek), more than 60% of the land is covered by hard surfaces (such as roads and buildings). In the more rural subwatersheds (Main Humber and East Humber), less than 15% of the land is covered by hard surfaces, allowing the rain to soak into the ground.
CONSERVATION AREAS AND PARKS
- Albion Hills Conservation Park
- Bond Lake
- Boyd Conservation Park
- Claireville Conservation Area
- Glen Haffy Conservation Park
- Kortright Centre for Conservation
- Lake St. George Field Centre
- Nashville Conservation Reserve
- The Village at Black Creek
Left to right: Lake St. George Field Centre; Claireville Conservation Area; Glen Haffy Conservation Park.
CLIMATE
Climate change impacts are being seen and felt locally in TRCA’s jurisdiction. Extreme heat and heavy rains are leading to more heat advisories and flooding, which affect the health and safety of the watershed and its residents.
These impacts will get worse unless we act to reduce the effects of greenhouse gas emissions. We also need to find ways to help our watersheds and communities better handle the effects of climate change.
Climate trends in the Humber River watershed are based on an analysis of climate parameters for two historical climate periods (1961-1990 and 1981-2010), and include:
- Air temperature is increasing (by 0.7°C on average between the two time periods).
- Very hot days above 30°C and 35°C have increased.
- Very cold days below -10°C and -20°C have decreased.
- Total annual precipitation has generally increased in the watershed (by 3.3%).
- The growing season is increasing (by 6.4 days).
LEARN HOW TRCA IS TAKING ACTION ON CLIMATE CHANGE.
Natural Hazards
The changing climate has increased the likelihood of more severe and frequent storms, which has worsened the impacts of land use change, and increased the risk of flooding and erosion.
There are currently seven Flood Vulnerable Clusters in the Humber River watershed (about 1% of the watershed area). These are areas in the floodplain with higher concentrations of roads/structures at risk of flooding and damage.
In terms of in-stream erosion risk, most of the Humber River watershed can be categorized as having moderate or high erosion sensitivity, and moderate stability.
Do you live in an area at risk of riverine flooding?
USE TRCA’s MAP VIEWER TO FIND OUT.
Watch this video to learn about Hurricane Hazel –
the largest flood in Toronto’s history and in the Humber River watershed:
Natural Heritage
The Humber River watershed has a rich natural heritage. This includes a well-connected system of natural areas like forests and meadows that provide homes and movement corridors to wildlife and plants.
In addition, urban forests are important for supporting healthy natural heritage in the watershed.
A healthy natural heritage system that can resist harmful changes and recover from damage is important for the health and safety of ecosystems and people. It helps to reduce the impacts of changing land use and climate, supports different types of plants and animals, and offers many services to people, such as better protection from floods and erosion, clean drinking water and air, and more opportunities for recreation.
In the Humber River watershed, the conditions of the natural heritage system and the urban forest varies by location.
Some areas (like the Main and East Humber subwatersheds) have a good amount of healthy natural areas, but the potential loss of natural cover and climate change impacts are big concerns.
Other areas that are more urbanized (like West Humber, Lower Humber, and Black Creek subwatersheds) generally have less natural cover and are of poorer quality.
KEY CHARACTERISTICS
- NATURAL COVER: The Humber River watershed is one of the most naturalized watersheds in TRCA’s jurisdiction, with about 31% covered by natural areas. Many of these are important for habitat connectivity and wildlife movements. Due to land use and climate impacts, we are seeing overall the loss of natural features such as forests, meadows, and wetlands.
- URBAN FORESTS: The amount of urban forest canopy cover remained stable at around 29% between 2009 and 2021.
- BIODIVERSITY: The Humber River watershed is home to many species, including 198 animal species and 343 vegetation communities. Many of the species sensitive to development pressures are primarily found outside of urban areas, including some that are considered Species at Risk.
- ISSUES OF CONCERN: Despite being rich in biodiversity and natural cover, the Humber River watershed is highly vulnerable to land use and climate change impacts. These impacts are more pronounced in urbanized areas, such as the middle to lower portions of the watershed, because the natural heritage is already under stress from urbanization.
Water Resources
The water resources in the Humber River watershed are made up of an interconnected system of groundwater and surface water.
This includes streams, rivers, lakes, and wetlands, as well as underground aquifers and areas that help replenish them.
It also includes water-related processes and functions, like the flow of water above and underground.
The water resource system provides homes to various fish species and insects, which are important for the health of the ecosystem.
A healthy water resource system helps keep our watersheds safe and resilient. It provides key services to our communities, such as storing water to reduce flooding, filtering water to keep it clean, and providing habitats for wildlife, such as fish, that in turn support recreational activities.
In the Humber River watershed, the condition of the water resource system varies. More natural areas in the Main and East Humber subwatersheds are in better shape, while more urbanized areas in the Black Creek and Lower Humber subwatersheds are in worse condition.
KEY CHARACTERISTICS
- SOURCE WATER: The Humber River starts at the Niagara Escarpment and Oak Ridges Moraine, within the Greenbelt, and flows for 126 kilometers before reaching Lake Ontario.
- FEATURES & AREAS: The Humber River watershed has approximately 1,896 km of regulated rivers and streams, 467 ha of inland lakes, including kettle lakes, as well as important groundwater areas such as Significant Groundwater Recharge Areas (42,355 ha) and Highly Vulnerable Aquifers (37,131 ha).
- BIODIVERSITY: The Humber River watershed is home to 71 known fish species, most of which are healthy. Fish communities are in better condition in the northern rural areas compared to the southern urbanized areas. The watershed is also home to many Species at Risk, such as the Redside Dace fish and Rapids Clubtail dragonfly.
- ISSUES OF CONCERN: The Humber River is important for communities and biodiversity, including fish species such as migratory Atlantic Salmon. However, its condition has been changing due to land use and climate impacts. For example, streamflow has increased substantially by about 20% compared to historical conditions. There are also 91 documented in-stream barriers that prevent fish from moving and impact their survival and reproduction. With climate change, cool and coldwater habitats for fish may become more vulnerable.
Water Quality
Clean water is critical for the health and safety of a watershed, its residents, and ecosystems. We need it for drinking, household use, and recreation activities such as swimming and fishing.
Clean water is also important for economic activities such as agriculture and manufacturing.
As climate and land use change, the water quality in the Humber River watershed changes as well.
By monitoring water quality over time and in different areas, we can identify issues and their causes, and find ways to fix them.
The quality of surface water varies across the Humber River watershed, with poorer water quality in the lower watershed.
As the number of hard surfaces such as roads and buildings increase, more pollution and chemicals will wash into the water.
Some agricultural practices can add large amounts of nutrients to the water, such as Phosphorus, which harms water quality.
Key contaminants of concern in the Humber River watershed include Chlorides, Phosphorus, metals, and E. coli bacteria.
Chlorides from road salt are a growing problem. Once chloride enters the soil and water, it stays there and builds up over time, making the water toxic for wildlife and threatening our water supply.
KEY CHARACTERISTICS
- CHLORIDES (e.g., from road salt):
- Chloride levels are high throughout the watershed.
- Chloride levels are rising in several areas, including at the mouth of the Humber River and in the headwaters of the Main Humber subwatershed.
- The highest chloride levels are in the Black Creek subwatershed, where they exceed Canadian Water Quality guidelines (acute effects 640 mg/L) for the protection of aquatic life.
- PHOSPHORUS (e.g., from fertilizers and sewage):
- Phosphorus levels are still a concern in many parts of the watershed.
- Trends show phosphorus levels above the Provincial Water Quality Guidelines (30 ug/L) in the headwaters, West Humber, and Black Creek subwatersheds, and at the mouth of the Humber River.
- METALS (e.g., from natural and industrial sources and roadways):
- Levels of metals like copper, chromium, lead, and nickel are decreasing.
- However, there are still high metal levels in the Main Humber subwatershed and near the mouth of the Humber River in the Lower Humber subwatershed.
- E. coli BACTERIA (e.g., from sewage and animal waste):
- E. coli bacteria remains a concern in the watershed.
- The highest levels are found in the West Humber, Lower Humber, and Black Creek subwatersheds.
Resources
Watershed Report Cards
Management Plans
- Albion Hills Conservation Park Master Plan (2017)
- Black Creek Pioneer Village North Master Plan (2015)
- Bolton Resource Management Tract Management Plan (2013)
- Boyd North and Glassco Park Management Plan, including Kortright Centre for Conservation (1999)
- Claireville Conservation Area Land Management Implementation Plan (2014)
- Cold Creek Conservation Area Management Plan (2002)
- Nashville Conservation Reserve Management Plan (2015)
- Oak Ridges Corridor Park Management Plan, including Bond Lake (2006)
- Oak Ridges Corridor Park East Management Plan (2011)
- TRCA Trail Strategy for the Greater Toronto Region (2019)
Supporting Documents
Learn More
Get Involved
Join TRCA for our annual Celebrate the Humber event, or report your Salmon sightings along the Humber River using our interactive Story Map!
Don’t forget to check out the TRCA calendar to learn about events near you, such as public plantings, educational presentations, nature walks, and more!
Visit TRCA’s Get Involved webpage to find something that interests you!
Contact
Questions about the Humber River watershed? Contact humber@trca.ca.