South Richvale Valleyland Restoration Works

Toronto and Region Conservation Authority (TRCA), in association with the City of Richmond Hill, is implementing remedial erosion control works along Patterson Creek, in order to provide long-term protection to at-risk municipal land and infrastructure.

Project Location

The South Richvale Valleyland Restoration Works project area is located adjacent to Patterson Creek, a tributary of the Don River, in the City of Richmond Hill. The work area includes three distinct sites, otherwise referred to as Site CC, C8 and C10, situated within the South Richvale Greenway. Site CC is located immediately south of Carrville Road, while Sites C8 and C10 are located approximately 350 metres and 450 metres downstream of Site CC, respectively (Figure 1). The project area’s closest major intersection is Bathurst Street and Carrville Road.

map showing project location
Figure 1. Project location and work areas. Source: TRCA, 2019.

Learn More About This Project

Project Background

In 2015, the City of Richmond Hill (the “City”) completed the Valleyland Capital Plan Study which identified 55 valleyland sites where City property or infrastructure is at risk of channel erosion and/or slope instability. The study identified several areas along Patterson Creek where remedial works are required to address existing erosion control structures that are near the end of their functional lifespan or where bank stabilization is needed to address new erosion risks.

The City had initially approached TRCA’s Engineering Projects group in 2015 to discuss coordinating remedial erosion control works along Patterson Creek with TRCA’s ongoing sanitary infrastructure protection project with the Regional Municipality of York. In 2017, the City and TRCA commenced the planning of remedial stabilization works and retained an engineering consulting firm, Terraprobe Inc., to complete a geotechnical investigation. Following completion of this assessment, TRCA retained Palmer to develop remedial designs for five high-priority sites identified within the valley and for future consideration for remediation.

Due to funding constraints, implementation of remedial works at each site was prioritized based on the level of risk associated with City owned property and infrastructure. The current available funding has been allocated to address the highest risk site (Sites CC) in 2019, and two additional high risk sites (Sites C8 and C10) in 2020.

Site CC refers to a failed cribwall structure located along the west bank of Patterson Creek (Figure 2). A 40 metre long scour along the west bank is at risk of undermining the adjacent pedestrian trail.  Remedial work for this site included the removal of the existing cribwall structure and the installation of a vegetated stone revetment along the west bank.

Photo of failed cribwall and scour at site CC
Figure 2. Failed cribwall, erosion scour and bank slumping along the west bank of Patterson Creek at Site CC. Source: TRCA, 2018.

Site C8 refers to a failing cribwall structure along the valley slope behind Cividale Court. High flow storm events have led to overtopping of the structure and subsequent outflanking at the downstream limit (Figure 3). Remedial work for this site includes the installation of a vegetated revetment behind the existing cribwall structure.

Failing cribwall and erosion scour at the toe of the valley slope at Site C8. Source: TRCA, 2018.
Figure 3. Failing cribwall and erosion scour at the toe of the valley slope at Site C8. Source: TRCA, 2018.

Site C10 refers to an outer meander of Patterson Creek that is armoured by a concrete slab revetment that is protruding into the creek (Figure 4). A corrugated steel pipe conveying drainage from a nearby outfall is located at the upstream limit of the revetment. Remedial works for this site includes replacing the existing concrete structure with a vegetated stone revetment and a woody bank treatment. The drainage pipe will also be replaced with an open vegetated swale.

Existing concrete slab revetment protruding into the creek at Site C10.
Figure 4. Existing concrete slab revetment protruding into the creek at Site C10. Source: TRCA, 2018.

Scope of Work

  • Geotechnical and geomorphic study (completed in 2017)
  • Development of detailed design (completed summer – winter 2018)
  • Obtain all necessary and approvals to proceed to construction (winter 2018 – spring 2019)
  • Construction at Site CC (completed summer 2019)
  • Construction at Sites C8 and C10 tentatively scheduled for summer 2020, pending available budget and receipt of permits and approvals

Construction Information

In anticipation of the summer 2020 remedial works, TRCA crews will be completing tree removals at Site C8 and C10 the week of March 16, 2020. The duration of the tree removal works is estimated to take 1-2 days.

For your safety, please respect all posted construction signs and stay clear of the work areas and equipment. Thank you for your cooperation and patience. 

Public Consultation

The project has been developed under a Schedule A+ Municipal Class Environmental Assessment.

All residential and commercial properties within the vicinity of the project area have been notified by the City through a Notice of Construction (NOC). Project information signs, which include details regarding trail closures, have been installed at the adjacent park entrances and/or access route points.

Project Updates

Week of September 30, 2019
Installation of the vegetated revetment and final site restoration has been completed at Site CC. Public access has been restored to the South Richvale Greenway trail, south of Carrville Road, and the staircase at Camgreen Court. Orange safety fencing has been installed at the top of the slope to support the establishment of vegetation. Thank you for remaining on the trail and refraining from accessing the newly restored areas.

Implementation of remedial works at Site C8 and C10 are tentatively scheduled for 2020. Further updates regarding 2020 construction will be provided in spring 2020.

completed vegetated revetment at site CC
Figure 5. Completed vegetated revetment and restoration plantings at Site CC. Source: TRCA, 2019.

Week of August 26, 2019
TRCA construction crews have completed installing stones along the toe of the bank at Site CC. Construction of the vegetated stone revetment is anticipated to be completed mid-September, as weather conditions permit.

Staff inspecting the placement of revetment stones at Site CC
Figure 6. TRCA construction staff inspecting the placement of the stones along the toe of the bank at Site CC. Source: TRCA, 2019.

Week of August 19, 2019
TRCA construction crews have completed site set up and are preparing to commence construction of the vegetated revetment. Construction is anticipated to end mid-September 2019, depending any potential weather delays.

photo of trail closure at Camgreen Court
Figure 7. Entrance to staircase at Camgreen Court to the South Richvale Greenway Walk is closed. Source: TRCA, 2019.

Week of July 15, 2019
Construction mobilization is scheduled to commence the week of August 5, 2019 for works at Site CC. Please note, South Richvale Greenway Walk, south of Carrville Road will be closed for the duration of works and is tentatively scheduled to reopen in late September 2019.

Week of May 13, 2019
TRCA is currently in the process of obtaining the necessary permits and approvals for implementation in the summer of 2019. Please note, project updates will be provided throughout the duration of construction.

Contact Us

The Project Planning Team is located at TRCA’s Boyd Field Centre Office in Vaughan:

Restoration and Infrastructure Division, Erosion Risk Management
9755 Canada Company Avenue
Vaughan, Ontario
L4H 0A3

For more information regarding this project, please use the contact details outlined below:
Phil Wolfraim, Project Manager 
Erosion Risk Management
Engineering Projects, Restoration and Infrastructure Division
Toronto and Region Conservation Authority

Kristina Delidjakova, Water Resources Coordinator
Environment and Infrastructure Services
Corporate Asset Management and Environment Services
City of Richmond Hill