Humber River Watershed Plan

Project Update & Release of the Humber River Watershed Characterization Report and Engagement Summary 1

October 23, 2023

Toronto and Region Conservation Authority (TRCA) has completed the first two stages of the watershed planning process for the new Humber River Watershed Plan (HRWP), including preparation/scoping (Stage 1) and watershed characterization (Stage 2).

We are pleased to release the Humber River Watershed Characterization Report and Characterization Factsheet, and to share the results and key messages from watershed characterization.

This report presents the findings from extensive watershed monitoring and technical characterization analyses and provides an overview of the current conditions of the watershed and trends since the last watershed plan was released in 2008.

   VIEW THE WATERSHED CHARACTERIZATION REPORT   
VIEW THE WATERSHED CHARACTERIZATION FACTSHEET

The Engagement Summary 1 has also been prepared.

This report summarizes engagement activities for the HRWP from May 2022 to October 2023, including results from the initial engagement survey in Fall 2022.

VIEW THE ENGAGEMENT SUMMARY 1

Work on the future management scenarios stage of the watershed planning process (Stage 3) is also currently underway, and will examine different potential future land use scenarios and climate change to understand how watershed conditions may change.

The results of the characterization and future management scenarios stages will identify the key issues and opportunities in the watershed, which will inform implementation planning (Stage 4) for the final watershed plan, including the development of a management framework identifying actions to ensure the long-term sustainability and resiliency of the watershed.

We’ll be sharing the results of the watershed characterization and future management scenarios stages, and looking for your feedback on the priorities for action to address the key issues facing the watershed, as well as your input to the objectives and indicators for the HRWP at our next engagement sessions later in 2024!

Please email us at humber@trca.ca with any questions or information you would like to share as we continue to develop the HRWP.

Toronto and Region Conservation Authority (TRCA) is in the process of developing a new watershed plan for the Humber River.

This plan will use the most recent data and science to characterize the current conditions of the watershed, provide insight on the future conditions of the watershed based on potential future land use and climate scenarios, and identify measures to protect, enhance, and restore the health of the watershed and build resiliency to land use and climate changes.

drone photograph of Humber River at James Garden

The development of the Humber River Watershed Plan (HRWP) is a collaborative effort between TRCA, Mississaugas of the Credit First Nation, 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.

Engagement with First Nations and Indigenous communities, as well as with watershed stakeholders, residents, and members of the public will occur throughout the watershed planning process to increase awareness of watershed planning and obtain input on the components of the watershed plan.

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Watershed Vision

Humber River watershed is protected, restored, and enhanced to sustain a more resilient, healthy, clean, and biodiverse ecosystem where we live in harmony with nature and celebrate the Humber River’s unique Indigenous history and cultural heritage.

In the fall of 2022, TRCA engaged watershed stakeholders, residents, and the public on what they would like to see in a watershed vision using an online survey and interactive polling during two virtual webinars. Variations of a vision based on these results were presented to the Humber River Watershed Plan Steering Committee consisting of TRCA, Mississaugas of the Credit First Nation, and our municipal partners.

The vision for the Humber River watershed reflects engagement and Steering Committee feedback. The new watershed plan will help us meet our vision for the watershed and ensure watershed health improves to benefit the natural environment and surrounding communities.

About the Humber River Watershed

The Humber River watershed is approximately 90,258 hectares in size and is the largest watershed in TRCA’s jurisdiction.

It has five subwatersheds – Black Creek, East Humber, Lower Humber, Main Humber, and West Humber – and spans from its headwaters on the Niagara Escarpment and Oak Ridges Moraine (and in the provincial Greenbelt) to the river’s mouth at Lake Ontario.

The Humber 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 five subwatersheds

Humber River Watershed Planning Process

Healthy watersheds provide numerous ecosystems services, such as supporting biodiversity, providing clean drinking water, reducing flood and erosion hazards, protecting the quality and quantity of water, and improving climate resiliency.

Watershed planning provides a systematic and comprehensive framework for ensuring healthy watersheds, and integrates natural systems into land use and infrastructure decision-making as well as climate adaptation planning.

It helps identify natural features and areas to protect and develop mitigation measures to minimize the impacts of various land use types and climate change.

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

Watershed  planning does not make land use and infrastructure planning decisions. Rather, it is intended to help municipalities make informed decisions on where and how to grow in a way that minimizes and/or mitigates impacts to  watershed  health.

The new Humber River Watershed Plan will also help inform various other TRCA and municipal initiatives, including ecosystem restoration and management, land management and acquisition, best practices for rural land uses, and low impact development and green infrastructure implementation.

bridge at the mouth of the Humber River

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

Our FAQs section provides additional information on the watershed planning process for the Humber River Watershed Plan.

PROJECT TIMELINE

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

blue checkmark in green circle   Watershed Characterization 2022-2023

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

Watershed Characterization Key Findings:

TRCA completed a bank stabilization project in 2022 to protect a pedestrian bridge and section of the Humber Trail from erosion hazards
NATURAL HAZARDS
Including flooding and erosion
There are seven Flood Vulnerable Clusters (FVCs) located in the watershed (which means there are flood risks in these areas), representing approximately 1.2% of the watershed area.
FVCs that receive drainage from multiple subwatersheds appear to compound the effect of development on peak flows.
Most of the watershed can be categorized as having moderate or high erosion sensitivity, and moderate stability.

 

aerial photograph showing developed residential areas as well as tree canopy coverage within the Humber River watershed
NATURAL HERITAGE SYSTEM & URBAN FOREST
Including terrestrial habitat quantity/quality, sensitive species, urban forest/tree canopy cover, etc.
Terrestrial natural cover (such as forests and meadows) continues to decrease (31.4% natural cover as of 2020, not including water such as streams and lakes).
There is generally higher quality habitat in the Main and East Humber subwatersheds in the northern part of the watershed, but generally poorer quality habitat in the West Humber, Lower Humber, and Black Creek subwatersheds due to smaller amounts of natural cover and urban influences.
The watershed supports many sensitive vegetation communities and plant/animal species including species at risk.
Many areas are important for habitat connectivity (e.g., wildlife movements). Approximately 61% of the watershed (mainly upper watershed) is a priority for regional habitat connectivity. Approximately 21% and 35% of the watershed is a priority for local forest-wetland, and wetland-wetland connectivity, respectively.
The terrestrial ecosystem is highly vulnerable to climate impacts within the more urbanized areas (middle to lower reaches of the watershed).
Urban forest canopy cover (i.e., trees and woody shrubs located on all private and public property within a watershed, including urbanized spaces and in forests) for the watershed has remained stable (at 29.1%) from 2009 to 2021.

 

a salmon attempts to leap over a barrier in the Humber River on the way to its spawning ground
WATER RESOURCE SYSTEM
Including aquatic habitat, in-stream barriers, groundwater conditions, streamflow etc.
The aquatic ecosystem is sensitive and aquatic habitat conditions vary across the subwatersheds (poorest in Black Creek and Lower Humber subwatersheds and best in the Main and East Humber subwatersheds).
The fish community is in relatively good health at the watershed scale, but there are large differences at the subwatershed scale between the northern rural areas and the southern urbanized areas (fish community health is “poor” in the Lower Humber and Black Creek subwatersheds, “fair” in the Main and West Humber subwatersheds, and “good” in the East Humber subwatershed). The average habitat health rating for benthic invertebrate communities is “fairly poor”.
There are 91 documented in-stream aquatic barriers preventing the movement of fish species.
There is approximately 4,279 ha of potentially occupied and potentially contributing habitat for Redside Dace in the Humber River and approximately 1,058 ha of potentially occupied and potentially contributing habitat (instream and terrestrial) for Rapids Clubtail (both endangered and sensitive indicator species).
Streamflow/discharge has increased by approximately 20.3% from historical conditions.

 

TRCA team member conducts water quality monitoring in the field
WATER QUALITY
Including parameters of concern relative to Provincial Water Quality Objectives or the Canadian Water Quality Guidelines.
Surface water quality is variable throughout the watershed, with poorest conditions often in the lower watershed.
Contaminants of particular concern include:

  • Chlorides (e.g., from road salts)
  • Phosphorus (e.g., from fertilizers and sewage cross connections)
  • Metals such as iron, cadmium, copper, and zinc (e.g., from natural and industrial sources and/or roadways)
  • E. coli bacteria (e.g., from sewage/animal wastes)

 

a city street is bathed in sunlight on a hot summer day
CLIMATE TRENDS
Climate trends based on an analysis of climate parameters for two historical climate periods (1961-1990 and 1981-2010) 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).

 

an Indigenous dignitary performs traditional music at the 2024 celebrate the Humber event
CULTURAL HERITAGE
The Humber River was designated as a Canadian Heritage River in 1999 based on its outstanding human heritage and recreational values and was officially included in the Canadian Heritage River System (CHRS), Canada’s national river conservation program.
The Humber River has a rich human history as a home for Indigenous peoples along its banks, as an ancient transportation route known as the Carrying Place Trail, and as a site of many of Toronto’s post-European settlement homes and industries.
Many archaeological sites (1,139), built heritage resources (2,391), and cultural heritage landscapes are located in the watershed (as of 2022).

READ THE FULL WATERSHED CHARACTERIZATION REPORT

Land Use in Humber River Watershed: 2002–2020

Area Estimates Change Estimates
2002
(area %)
2012
(area %)
2020
(area %)
2002-2012
(% change from 2002)
2012-2020
(% 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** 17.8% 21.7% 23.1% +21.9% +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.

**This calculation of impervious cover (hard surfaces) assumes that water (e.g., lakes, rivers, ponds) is 0% impervious (from an ecological perspective).

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

 

green circle   Future Management Scenarios 2023-2024

PURPOSE: Examines different potential future management scenarios to understand how watershed conditions may change.

Through extensive watershed modeling and impact analysis, the future management scenarios will help us determine how the watershed may respond to potential future land use and climate changes (i.e., will conditions improve, stay the same, deteriorate, or significantly deteriorate) under each potential future management scenario.

It is important to note that scenario analysis does not result in decisions about the type and configuration of land uses. Instead, scenario analysis helps to inform municipal planning decisions.

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

The potential future management scenarios are currently being developed collaboratively by the Humber River Watershed Plan Steering Committee (consisting of TRCA, Mississaugas of the Credit First Nation, and our municipal partners).

The potential future management scenarios will help us assess the impacts of different future land uses and different levels of watershed enhancements (e.g., improvements to stormwater management, increased natural cover, and increased urban forest canopy cover), as well as the impacts of climate change, where possible.

Future Management Scenario Analysis Process:

a diagram illustrating the process TRCA has used to examine potential future land use scenarios for the Humber River Watershed

 

green circle   Implementation Planning 2024-2025

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

 

Contact Us

If you have any questions about the development of the Humber River Watershed Plan, please email us at humber@trca.ca.