To ensure that service is reliable and its facilities are safe, Hydro-Québec must control the vegetation in its transmission and distribution line rights-of-way and on dikes and dams. Environmental considerations are incorporated into all vegetation control operations. For example, long-term results show that mechanical treatment with rational use of herbicides promotes biodiversity (pamphlet in French only) and the growth and maintenance of compatible vegetation in transmission line rights-of-way. No herbicides are used in distribution system maintenance.

For the past five years, we have been using Light Detection And Ranging (LIDAR) technology to compare ground cover height with conductor height in order to determine what operations are required to control vegetation growing in line rights-of-way. The gradual optimization of vegetation inspection in rights-of-way will also maintain system reliability through improved knowledge of the minimum clearances that are safe for the public, workers and the system.

Video: Distribution system vegetation control

For the safety of the public and workers, and to prevent outages and ensure reliable system operation, Hydro-Québec controls vegetation around distribution system power lines. Clearing is done in an environmentally responsible manner and preserves biodiversity near the lines. Vegetation control operations are planned by Hydro-Québec's forest engineers and technicians, and carried out by qualified contractors.

Rethinking reforestation: a strategic guide for increasing the canopy and boosting urban forest resiliency in Greater Montréal

Two urban studies were completed in 2016 as part of the work carried out by the NSERC/Hydro-Québec Industrial Research Chair on the Control of Tree Growth. Their aim: to increase knowledge and create decision-making tools to reconcile the efficient control of distribution network vegetation with expanding the canopy and boosting urban forest resiliency in the face of global change. The studies have led to the publication of a guide (available in French only) for Québec urban decision-makers and practitioners, written in partnership with the Communauté métropolitaine de Montréal and under the direction of Jour de la Terre/Earth Day Québec. The guide reviews the research findings to date.

Activities in 2016

  • Integrated vegetation control pilot project using a low-flow, multiple-nozzle GPS-enabled mechanized spray system. Initial testing in the line right-of-way served to confirm the usefulness of this approach as well as compare the efficacy of two herbicide formulations and validate the accuracy of the GPS.

Vegetation control along transmission line rights-of-way

The table shows the areas treated mechanically, those treated selectively with herbicides and the total area treated. The percentage between areas treated mechanically and the total area treated is then indicated.

In 2016, the total area of transmission line rights-of-way was 172,961 ha.

Vegetation control along dikes and dams

The table shows the areas treated mechanically, those treated selectively with herbicides and the total area treated. The percentage between areas treated mechanically and the total area treated is then indicated.

Herbicide use and mechanical treatment vary, depending on the vegetation-control planning cycle. The proportion of herbicides used changes annually.