Etobicoke Creek Watershed Plan

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

Watershed Characterization Key Findings

WATER RESOURCE SYSTEM:
Includes aquatic habitat, in-stream barriers, groundwater conditions, etc.

• Among larger watersheds in TRCA’s jurisdiction (i.e. >200 km²), Etobicoke Creek has the second highest annual runoff at 402 mm/year, second only to the Don River.
• The average habitat health rating for fish is “fair” and for benthic communities is “poor”. There has been little to no change in aquatic habitat quality since 2002.
• There are a large number of in-stream barriers that prevent the movement of species and only approximately 49.6% natural cover within the riparian corridor (i.e. within 30 metres of streams).

NATURAL HERITAGE SYSTEM/URBAN FOREST:
Includes habitat quantity and quality, tree canopy, sensitive species, etc.

• Approximately 11.7% of the watershed consists of natural cover (not including water), which is similar to other heavily urbanized watersheds, with natural cover continuing to decrease (e.g. forest cover).
• Generally, habitat quality is poor with some fair quality habitat in the headwaters, but the watershed still supports regional biodiversity including some sensitive plant and animal species, primarily in the headwaters.
• Approximately 39% and 18% of the watershed is a priority for regional and local connectivity among habitat patches, respectively.
• Existing natural cover is highly vulnerable to the effects of climate change in urban areas.
• Urban forest canopy cover (i.e. trees and tall shrubs) is 14.7% and has remained stable from 2009 to 2018.

WATER QUALITY:
Includes parameters of concern relative to Provincial Water Quality Objectives (PWQO) or Canadian Water Quality Guideline (CWQG).

• Surface water quality is generally poor compared to other TRCA watersheds. Contaminants of particular concern include:
• Chlorides (e.g. from road salts)
• Phosphorus (e.g. from fertilizers)
• E. coli bacteria (e.g. from sewage/animal wastes)
• Metals such as copper and zinc (e.g. from industrial sources and/or roadways)
• Exceedances of chlorides and nitrates in groundwater were observed.

NATURAL HAZARDS:
Includes flooding and erosion.

• There are six flood vulnerable clusters (FVCs) with a total area of 508 hectares (ha).
• Most of the watershed can be categorized as medium or high erosion sensitivity.

Land Use in Etobicoke Creek Watershed: 2002-2019

*Rural includes land use classifications such as agriculture, golf courses, open space, hydro corridors, 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.

**i.e. hard surfaces

Select image below to view full-sized land use map.

READ THE FULL WATERSHED CHARACTERIZATION REPORT

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

Four potential future management scenarios assessed the impacts of different land uses and different levels of watershed enhancements (e.g. improvements to stormwater management, increased natural cover, and increased urban forest canopy), as well as the impacts of climate change:

• Scenario 1: Urban Expansion with Minimal Enhancements – Further urbanization in the Headwaters with no enhancements to natural cover and stormwater management.
• Scenario 2: Urban Expansion with Mid-Range Enhancements – Further urbanization in the Headwaters with moderate enhancements to natural cover and stormwater management.
• Scenario 3: Urban Expansion with Optimal Enhancements – Further urbanization in the Headwaters with optimal enhancements to natural cover and stormwater management.
• Scenario 4: Existing Urban Boundary with Optimal Enhancements – Current urban boundary is maintained with optimal enhancements to natural cover and stormwater management.

Scenario analysis does not result in decisions about the type and configuration of land uses. Instead, scenario analysis helps to inform municipal planning decisions.

Future Management Scenario Analysis Process

Future Management Scenarios: Key Findings

WATER RESOURCE SYSTEM
Includes aquatic habitat, in-stream barriers, groundwater conditions, etc.

• Aquatic habitat quality will decrease as impervious surface amounts increase (and will likely become non-supporting if effective impervious cover exceeds 25%).
• With increasing urbanization, more sensitive fish species will be replaced with species more tolerant of disturbance, and benthic communities will shift towards more pollution tolerant species.
• With natural cover enhancements, the number of coolwater, coldwater, and stable temperature stream reaches could increase and make the system more resilient to climate change.
• Groundwater discharge and recharge will be negatively affected in the headwaters without enhancements to natural cover, urban forest, stormwater management, and LID implementation.

NATURAL HERITAGE SYSTEM/URBAN FOREST
Includes habitat quantity and quality, tree canopy, sensitive species, etc.

• Even with optimal natural cover enhancements, this watershed remains below recommended federal guidelines for natural cover quantity and TRCA’s terrestrial NHS target, but any increase will provide a benefit to biodiversity and other ecosystem services.
• There are opportunities to increase the quantity and quality of the urban forest to improve ecosystem functions, provide ecosystems goods and services, increase climate resiliency, and provide socio-economic benefits.

WATER QUALITY
Focused on total suspended solids and chlorides.

• Changes in water quality parameters (e.g., Total Suspended Solids and chlorides) demonstrate the negative impact of urbanization and the benefits of improved stormwater management and natural cover enhancements in a changing climate.

NATURAL HAZARDS
Includes flooding and erosion.

• Increasing enhancements to natural cover and stormwater management help reduce peak flow levels, though not as effectively when considering climate change.
• Land use changes can manage peak flows for all design storms through enhancements and interventions (if TRCA’s stormwater management quantity criteria for the Etobicoke Creek Headwaters is applied), but climate change will cause peak flows to exceed current stormwater infrastructure design standards.
• Increasing natural cover and enhancing stormwater management help mitigate erosion, which would otherwise increase with further urbanization.

READ THE FUTURE MANAGEMENT SCENARIO ANALYSIS REPORT

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

Etobicoke Creek Watershed Plan: Highlights

This stage involved the development of a management framework with three goals, eight objectives, 10 indicators, and 36 management actions outlining how to protect, enhance, and restore watershed health.

Select the image below to download a copy of the management framework.

The management framework is designed to address existing watershed issues and mitigate impacts from potential future land uses and climate change.

The management framework is focused on:

• Achieving more sustainable land use and infrastructure development patterns through the use of low impact development and green infrastructure, improved stormwater management, mitigating flood and erosion risk, and improving rural land stewardship.
• Protecting, enhancing, and restoring the Water Resource System and improving aquatic habitat connectivity.
• Protecting, enhancing, and restoring the Natural Heritage System and increasing urban forest cover.

An inventory, monitoring, and evaluation program was also developed to help track implementation progress, evaluate and report on whether watershed conditions are improving, and ensure mechanisms are in place to adjust and adapt approaches as needed.

Once final approvals and endorsements of the Etobicoke Creek Watershed Plan have been obtained in 2024 from municipal committees and councils and from TRCA’s Board of Directors, implementation of the watershed plan will begin.

The Etobicoke Creek Watershed Plan is intended to be in effect for 10 years from when it is finalized and approved. Collaborative and comprehensive implementation, tracking, and reporting of all aspects of the management framework will be essential to fully realize the vision for the watershed and to improve watershed health and ensure sustainability of its ecosystem services for current and future generations.

An Implementation Steering Committee consisting of TRCA, the municipalities within the watershed, Mississaugas of the Credit First Nation, and the Greater Toronto Airports Authority will be established in 2024 to guide and support implementation, and will be facilitated by TRCA.

The Implementation Steering Committee will work together to create a detailed implementation, tracking, and reporting plan to ensure commitment to and accountability for implementation on the part of TRCA, our municipal partners, and other stakeholders.

Through the implementation of the Etobicoke Creek Watershed Plan, all watershed partners and stakeholders can contribute to a healthier, more sustainable, and more resilient watershed that can provide long-term benefits to all residents.