Public Notice - 2024 Vegetation Maintenance Program - Hydro One

As part of the ongoing maintenance programs to ensure the safe reliable delivery of electricity to customers across the province, Hydro One is planning the routine maintenance of vegetation on our transmission corridor.

This corridor is a combination of Easement and Infrastructure Ontario owned lands. This routine maintenance work has been registered with the MOE for ESA-SAR mitigation plans (Ministry of Environment, Endangered Species Act-Species at Risk).

The necessary maintenance work will consist of removing danger trees, trimming trees and brush control using various techniques including but not limited to certified insulated aerial devices, use of mechanical equipment, manual hand cutting and herbicide application.

Regarding our use of herbicide, we are applying herbicide to cut stems and to standing non-compatible, fast-growing/invasive vegetation as per Ontario Regulation 63/09. (Pesticides Act) A low-volume government-approved herbicide, Garlon (Registration #29334 or 28945) will be selectively applied by our licensed staff to prevent regrowth of vegetation.

Vegetation management is necessary to ensure that minimum clearances are maintained between vegetation and energized apparatus to effectively manage potential public safety hazards and tree-caused outages.

Hydro One’s compliance to NERC Federal Regulations are as follows:

NERC Compliance & Purpose

To improve the reliability of the electric transmission systems by preventing outages from vegetation located on transmission rights-of-way (ROW) and minimizing outages from vegetation located adjacent to ROW, maintaining clearances between transmission lines and vegetation on and along transmission ROW, and reporting vegetation related outages of the transmission systems to the respective Regional Reliability Organizations (RRO) and the North American Electric Reliability Corporation (NERC).

Who is Applicable under NERC Federal Regulation?

  • Transmission/Generation Owners
  • Regional Reliability Organization/Regional Entity
  • This standard shall apply to all transmission lines operated at 200 kV and above and to any lower voltage lines designated by the RRO as critical to the reliability of the electric system in the region.

NERC Requirements

  • The Transmission Owner shall prepare, and keep current, a formal transmission vegetation management program (TVMP). The TVMP shall include the Transmission Owner’s objectives, practices, approved procedures, and work specifications.
  • The TVMP shall define a schedule for and the type (aerial, ground) of ROW vegetation inspections. This schedule should be flexible enough to adjust for changing conditions. The inspection schedule shall be based on the anticipated growth of vegetation and any other environmental or operational factors that could impact the relationship of vegetation to the Transmission Owner’s transmission lines.
  • The Transmission Owner, in the TVMP, shall identify and document clearances between vegetation and any overhead, ungrounded supply conductors, taking into consideration transmission line voltage, the effects of ambient temperature on conductor sag under maximum design loading, and the effects of wind velocities on conductor sway. Specifically, the Transmission Owner shall establish clearances to be achieved at the time of.

With regards to the transmission corridor vegetation maintenance required, we are reviewing our records for environmentally sensitive areas and developing practical mitigation plans. We request that you identify areas of environmental concern for this future work and advise on any specific concerns so we can supplement our work package plan.

Your comments and concurrence to proceed with this necessary routine cycle maintenance is requested ASAP. Further information and arrangements for a site review can be made by contacting me at or by phone: 519-476-3925.

Thank you for your co-operation and assistance while Hydro One plans for their scheduled maintenance.

Please see the attached map of this project highlighted in blue:

Project Map 

Garlon RTU Herbicide

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