Humber River Watershed Plan


November 1, 2022

The initial engagement and commenting period for the development of the new Humber River Watershed Plan (HRWP) is now complete.

Thank you to those who completed our survey or attended one of our webinars and provided input.

Your feedback will help us identify the important watershed themes/words that will guide the development of the vision statement for the watershed, the key watershed issues for the HRWP, and any climate or weather-related changes or impacts experience/observed in the watershed.

TRCA will now review and compile all input received, and will release an Engagement Summary once completed.

If you have any additional comments on the development of the HRWP, or information you would like to share on the Humber River watershed, please email us at

If you weren’t able to attend one of our webinars, you can watch our virtual presentation at your convenience any time:

Toronto and Region Conservation Authority (TRCA) is embarking on the development of a new watershed plan for the Humber River.

This plan will use the most recent data and science to understand the current conditions of the watershed, and provide insight on the future conditions of the watershed based on potential land use and climate scenarios.

The watershed plan will be used to inform various TRCA and municipal initiatives including land use and infrastructure planning, ecosystem restoration and management, and green infrastructure initiatives.

drone photograph of Humber River at James Garden

The development of the Humber River Watershed Plan is a collaborative effort between TRCA, City of Toronto, Region of Peel, Region of York, Dufferin County, Simcoe County, City of Brampton, Town of Caledon, City of Vaughan, Township of King, City of Richmond Hill, Town of Aurora, Town of Mono, and Township of Adjala-Tosorontio.

Public, stakeholder, and Indigenous community engagement will occur throughout the watershed planning process.


Where is the Humber River Watershed?

The Humber River watershed is approximately 90,257 hectares in size and is the largest watershed in TRCA’s jurisdiction. It is the only Canadian Heritage River in the Greater Toronto Area.

Select the image below to view the full-sized map.

map of the Humber River watershed and its subwatersheds

Land Use in Humber River Watershed:
2002 – 2020

Area Estimates Change Estimates
(area %)
(area %)
(area %)
(% change from 2002)
(% change from 2012)
Urban 20.7% 24.9% 26.7% 20.3% 7.2%
Rural* 45.3% 41.2% 40.6% -9.1% -1.5%
Natural 34.0% 33.9% 32.7% -0.3% -3.5%
Impervious Cover 18.9% 23.0% 24.5% 21.7% 6.5%

*Rural includes land use classifications such as agriculture, golf courses, recreational/open space, cemetery, etc. These types of land uses cannot be considered natural, nor can they be considered urban as they still have low amounts of impervious surfaces.

Select the image below to view the full-sized maps.

series of maps comparing land use in the Humber River watershed today with land use in 2012 and 2002

Humber River Watershed Planning Process

Watershed planning helps to inform how land use and infrastructure planning influence and affect the natural ecology of the watershed.

The last Humber River Watershed Plan, Pathways to a Healthy Humber, was completed in 2008, with an accompanying Implementation Guide.

The new Humber River Watershed Plan will provide updated information and a framework moving forward.

the Old Mill Bridge spans the Humber River at Etienne Brule Park


Watershed planning is a multi-year process. Select below to find out what is included at each stage.

Watershed Characterization 2022-2023Click to expand

PURPOSE: Identifies the current conditions of the watershed (including habitat quality and quantity, water quality, flooding, and erosion issues).

Watershed characterization will determine the current conditions of:

  • The Water Resource System, which includes aquatic habitat, in-stream barriers, and groundwater conditions.
  • The Natural Heritage System, which includes the urban forest/tree canopy, habitat quantity/quality, and sensitive species.
  • Water Quality, which includes parameters of concern (for example chlorides, phosphorus, E. coli bacteria, and metals such as copper and zinc) relative to Provincial Water Quality Objectives or the Canadian Water Quality Guidelines.
  • Natural Hazards such as flooding and erosion

bridge at the mouth of the Humber River

Future Management Scenarios 2022-2024Click to expand

PURPOSE: Examines different potential future land use scenarios and climate change, where possible, to understand how watershed conditions may change.

Future management scenarios will be determined collaboratively by TRCA and our municipal partners.

Through watershed modeling and impact analysis, we will look at how watershed conditions will change (i.e., improve, stay the same, deteriorate, or significantly deteriorate) under each potential future management scenario.

drone image of the Humber River and Pierre Berton trail in the William Granger Greenway

Implementation Planning 2024-2025Click to expand

PURPOSE: Identifies measures to protect, enhance, and restore the watershed based on results from the Watershed Characterization and Future Management Scenarios stages.

drone photograph of Humber River at James Garden

Reports and Resources

Contact Us

If you have any questions about the development of the Humber River Watershed Plan, please email us at