The program aims to encourage the growth of low-growing, relatively sparse vegetation in power line rights-of-ways. For instance, in woodland settings we protect shrubs and bushes that are already well established like dogwood, red currant, wild raspberry, viburnum, yew and grasses, etc.
Over time, these shrubs and grasses take over the right-of-way, making future vegetation control operations easier and providing a good plant cover for various animal species.
The personnel in charge of the program include experts working in forestry (forestry engineers and technicians) and the environment (biologists and geographers).
The work is carried out by qualified companies, whose workers are trained to meet Hydro-Québec’s safety requirements.
The integrated vegetation management program encompasses several recurring activities:
- Planning the work
- Conducting an inventory of vegetation and sensitive features
- Determining how the work will be carried out
- Carrying out the work
- Inspecting the quality of the work
1. Planning the work
Every year, Hydro-Québec’s experts determine where work is required to bring the vegetation under control. Their plan depends on several factors, the main one being maintaining a safe distance between vegetation and the power lines.
As a result, there is no need to clear every right-of-way every year. The frequency of clearing operations depends on the type of vegetation in the right-of-way and the time it takes for it to grow back close to the power lines.
The more northerly the transmission line, the longer the right-of-way can go without clearing because vegetation grows more slowly in cooler areas. In southern Québec, where vegetation grows faster, clearing operations are more frequent. Consequently, clearing intervals in Hydro-Québec’s rights-of-way vary from three to 13 years.
2. Conducting an inventory of vegetation and sensitive features
Effective planning of vegetation management work requires knowledge of what is in the rights-of-way. Hydro-Québec has several ways to obtain that information. Here are a few examples.
- Vegetation, streams and wetlands are inventoried using high-resolution aerial photos that are analyzed using specialized software that provides 3D views.
- Remote aerial surveys using LIDAR (light detection and ranging) laser technology measure the precise distances between trees and power lines.
- Other sensitive environmental features are inventoried using data provided by federal, provincial and municipal governments. Armed with this information, we are able to take the necessary precautions to protect sensitive areas like water intakes and the habitats of threatened and vulnerable plant and animal species.
3. Determining how the work will be carried out
To make it easier to plan upcoming work, every right-of-way is subdivided into sections. Using this approach, Hydro-Québec’s forestry engineers and technicians can determine how best to do their work, section by section.
A number of aspects are taken into account:
- The height and density of the vegetation
- The site’s physical characteristics (landforms, accessibility, etc.)
- Sensitive features (such as streams)
- Applicable laws and regulations (especially the Pesticides Management Code)
- Commitments and agreements made with landowners and community organizations
The most commonly used method for clearing rights-of-way is selective mechanical clearing using manual brush cutters.
To minimize debris, workers can apply a diluted herbicide solution to stumps with brush cutters equipped with a spraying system. In this way, the tree can be felled and the stump disposed of in a single step.
Selective use of herbicides
All herbicides used by Hydro-Québec in rights-of-way are selective herbicides, meaning they act only on woody vegetation. They are approved by Health Canada and applied as prescribed by law. They pose no danger for wildlife or the general public because we take great care to apply them according to industry standards. For example, Hydro-Québec creates buffer zones around waterways, wells and water intakes where no herbicides can be used.
Debris and residual wood
At the planning stage, Hydro-Québec’s experts also determine how debris (branches, leaves, etc.) and residual wood (trunks) will be disposed of.
Most often, the debris is left scattered on the ground, while residual wood is stacked. The wood debris scattered in the rights-of-way promote biodiversity. The debris provides resting areas and shelter for several animal species, and attracts certain bird species.
Before the work starts, Hydro-Québec sends a notice to the relevant landowners.
Whenever herbicides are applied in rights-of-way, Hydro-Québec produces various documents as required by the Pesticides Management Code, a regulation of the Pesticides Act:
- Notice to the Ministère du Développement durable, de l’Environnement et de la Lutte contre les changements climatiques
- Notice to the municipalities and RCMs before the work begins
- Notice in a regional media announcing the upcoming work
4. Carrying out the work
Unless special circumstances make it impossible, vegetation management work starts after the snow melts and continues for as long as weather permits.
Vegetation management contracts are awarded through a tendering process to companies qualified to bid by Hydro-Québec. For example, workers who perform mechanical clearing are required to have forestry management skills such as brush and tree cutting. In addition, under the Pesticides Act and the Environment Quality Act, the selective application of herbicides must always be supervised by workers who hold a Certificate of Authorization for the Use of Pesticides.
5. Inspecting the quality of the work
All work is checked by a Hydro-Québec representative, who makes sure it complies with the specifications. If any problems are identified, the representative notifies the company that performed the work so that it can make the necessary corrections.
A quality control process encourages companies to strive for continuous improvement. Their work is evaluated on a continuous basis during their contract, and they receive yearly evaluations.
- Maîtrise intégrée de la végétation dans les emprises (in French only) [PDF – 4.59 Mo]
- Biodiversité dans les emprises (in French only) [PDF – 1,8 Mo]
- Effet des emprises de lignes sur les ravages du cerf de Virginie (in French only) [PDF – 2,6 Mo]
- Castors dans les emprises (in French only) [PDF – 2,6 Mo]
- La conservation de la biodiversité dans les emprises de lignes du réseau de transport (in French only) [PDF – 6,4 Mo]
- Authorization for a project in a transmission line right-of-way (bike path, reseeding, garden, etc.)