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Royal Rouge Trail Erosion Control Project

Toronto and Region Conservation Authority (TRCA) is preparing to undertake remedial erosion control works along a section of the Rouge Valley corridor at the rear Nos. 30 – 48 Royal Rouge Trail in the City of Toronto, where slope instability and ongoing erosion are creating a risk to residential properties.


Background of Project

In 1989, a homeowner on Royal Rouge Trail contacted TRCA to express concern over the instability of the valley wall and the potential long-term risk to their home. After several small-scale studies and minor erosion control works in the years following the initial identification of the problem, TRCA completed a detailed slope stability and erosion risk assessment to confirm the cause(s) and extent of the problem, the results of which indicated that major erosion control work was required to provide long-term protection for the ten (10) residential properties along Royal Rouge Trail within the study area.

Project Objectives

The key project objective is to provide long-term protection for the residential properties in the affected area while maintaining the health and integrity of the valley corridor. As a result, risk to public safety and existing structures will be reduced, and terrestrial habitat conditions will be improved. TRCA has examined a number of alternatives to achieve these objectives including slope trimming, intense vegetation of the slope, soil retaining structures, and drainage improvements.

Planning Mechanism for the Undertaking

TRCA must conduct its remedial flood and erosion control projects in accordance with the Environmental Assessment Act (EAA). Recognizing that common elements exist in addressing flood and erosion problems, a more efficient approach to environmental assessment was developed by Conservation Ontario for all conservation authorities known as the Class Environmental Assessment for Remedial Flood and Erosion Control Projects (Class EA). The Class EA approach is considered a suitable means for the planning of remedial flood and erosion control projects because it provides a consistent, streamlined process that ensures compliance with Environmental Assessment Act (EAA) requirements.

In September 2011, TRCA submitted the Environmental Study Report in support of the Royal Rouge Trail Erosion Control Project for a 30 day public review period and approval by the Ministry of the Environment under subsection 7 (1) of the Environmental Assessment Act (EAA). In October 2011, the project was approved.

Public and Agency Consultation

The Class EA process provides that all views respecting a proposed remedial flood or erosion control project be taken into consideration during the planning and design of remedial flood and erosion control projects. The formation of a Community Liaison Committee (CLC) has allowed concerned citizens, local interest groups and non-governmental organizations to voice issues of public concern as well as assisted in the planning and design process of the project.

Through a series of CLC meetings, a range of alternative options have been considered, which included traditional solutions such as intense vegetation, trimming, and retaining wall structures. In addition to providing feedback on technical and economic considerations, the members provided great insight into the importance of preserving the Rouge Valley Corridor. The CLC assisted with selection of a preferred alternative.

The Project

The project area has been divided into two sectors based on the type and extent of the erosion and instability processes along the valley wall. The project area was divided into the following two sites:

  • Site A – Nos. 30 to 40 Royal Rouge Trail
  • Site B – Nos. 42 to 48 Royal Rouge Trail

The preferred solution determined through the Class EA process was trimming and intense re-vegetation for Site A, and a “green” retaining structure that allows for the most cost-effective use of land while achieving maximum aesthetic and environmental value for Site B. Primary considerations for these selections included:

  • Providing adequate long-term stability of the valley wall and protection of public safety
  • Compatibility with, and minimizing impacts on, the surrounding physical and biological environment
  • Providing terrestrial enhancements to the greatest extent possible
  • Cost effectiveness
  • Public opinion

Funding for the construction of the proposed works has been identified in TRCA's 2012 capital budget, generously funded by the City of Toronto. Pending the receipt of all necessary approvals, implementation of the preferred remedial measure is anticipated to commence August 2012.

For more information, please contact Patricia Newland, Project Manager at (416) 392-9690 or

Project Status Updates

As of August 31, 2012

TRCA's contractor, TBG Landscape Professionals, mobilized on August 27, 2012. The contractor is currently constructing the temporary access road behind properties at Nos. 30 to 48 Royal Rouge Trail. Once the temporary access road has been constructed, the contractor will simultaniously commence slope regrading at Site A and construction of the retaining walls at Site B starting with the eastern limit behind No. 48 Royal Rouge Trail.

Construction of the temporary access route at the Royal Rouge Trail Erosion Control Project

As of September 17, 2012

The over-steepened portions of the slope behind the properties at 30 to 40 Royal Rouge Trail (Site A) are being regraded.

Construction of the Mechanically Stabilized Earth (MSE) Wall has commenced behind the properties at 42 to 48 Royal Rouge Trail (Site B). The photo below depicts the base layer of the MSE wall at the eastern limit of the project behind 48 Royal Rouge Trail.

Base of Mechanically Stabilized Earth (MSE) Wall as of September 17, 2012

As of October 10, 2012

Construction of the MSE retaining wall is currently underway. As shown in the photo below, the contractor has constructed up to tier 7 of 17 behind the properties at Site B.

Construction of the MSE retaining wall as of October 10, 2012

As of November 30, 2012

Construction of the MSE retaining wall at Site B and regrading of the slopes at Site A has been completed. Final site restoration will be completed by Spring 2013.

Construction photo from Nov 30, 2012

Slope regrading and re-vegetation at Site A.