Patterson Creek Sanitary Infrastructure Protection Project

Toronto and Region Conservation Authority (TRCA) is preparing to implement regional infrastructure protection works along Patterson Creek, in the City of Richmond Hill, in order to provide long-term protection to at-risk sanitary sewer infrastructure.
Project Location

The Patterson Creek Sanitary Infrastructure Protection Project is located along two distinct sections of the Patterson Creek watercourse, situated within the Don River watershed.

Both project areas are located northeast of Bathurst Street and Carrville Road, in the City of Richmond Hill. Sites I-075 and P-1005 are located within private and municipally owned property at the rear of Grist Mills Park. Sites I-070 and P-107 are situated within municipally owned property at the rear of the Richvale Community Centre and Athletic Park and St. Charles Garnier Catholic School.

Learn More About This Project

Project Background

In 2011, TRCA developed the Infrastructure Hazard Monitoring Program (IHMP). The purpose of the IHMP is to ensure timely identification of risk to infrastructure due to watercourse activity (i.e. channel migration, widening, etc.) and efficient prioritization and mitigation of such risks in collaboration with stakeholders.

The IHMP broadly divides watercourse erosion risks into two types of sites: intersection sites to assess the risk of bed erosion where the sewer crosses a watercourse, and proximity sites to assess the risk of bank erosion and lateral channel adjustments in close vicinity to the infrastructure. Intersection sites are categorized using an “I-” identifier, while proximity sites are categorized using a “P-” identifier.

In regards to this particular project, the infrastructure at risk includes a 525 mm diameter sanitary main, owned by the Region of York, which was installed in October 1971. Over the past 48 years, Patterson Creek naturally migrated within the flood plain and has shifted over or in close proximity to the sanitary main and associated maintenance holes. As such, the IHMP identified Sites I-075, P-1005, I-070, and P-107 as requiring remedial works as sanitary infrastructure is exposed or at the immediate risk of exposure.

Figure 2. Exposed maintenance hole chimney on the east bank of Patterson Creek at Site I-075. Source: TRCA, 2018.
Figure 3. Exposed maintenance hole chimney on the east bank of Patterson Creek at Site P-1005. Source: TRCA, 2018.
Figure 4. Displaced concrete weir (proposed to be removed) at the upstream portion of Site P-107 where the sanitary line is at risk of exposure. Source: TRCA, 2018.
Figure 5. Erosion at Site I-070 where the sanitary line crosses the watercourse and is at risk of exposure. Source: TRCA, 2018.

In 2017, TRCA retained Palmer Environmental Consulting Group (PECG) to conduct a scoped geomorphic and environmental impact assessment of the proposed project area. Following completion of the study, detailed designs utilizing natural channel design principles were developed throughout 2018.

The remedial designs have been refined through consultation with multiple Regulatory agencies to provide adequate protection to sanitary infrastructure, while at the same time providing an overall ecological benefit to the area.

Funding for the geomorphic study and detailed design development of these remedial works has been provided through the Clean Water and Wastewater Funding (CWWF) Grant Program from Infrastructure Canada and Infrastructure Ontario. For more information regarding the CWWF program, please click here.

Scope of Work 
  • Geomorphic study and Environmental Impact Statement (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 I-070/P-107 and P-1005/I-075 is tentatively scheduled for summer 2020, pending receipt of permits and approvals
Construction Information

Further information regarding the work area, access routes, trail closures, tentative schedule and construction highlights will be provided in spring 2020.

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 will be notified by TRCA through a hand delivered Notice of Project Commencement (NOPC). Project information signs, which will include details regarding trail closures, will be installed at the adjacent park entrances and/or access route points.

Project Updates

Week of June 24, 2019

Implementation at I-070/P-107 and P-1005/I-075 has been postponed to summer 2020, pending the receipt of all permits and approvals. Please check back here for further updates closer to 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 & Infrastructure Division
phil.wolfraim@trca.ca
416.661.6600