315/25‑kV Saint‑Jean Substation and 315‑kV Supply Line

Environmental approach

Landscaping the right‑of‑way: an innovative concept fostering urban biodiversity

Following the project environmental assessment and communication activities, a working committee made up of representatives from the city of Dollard‑Des‑Ormeaux and Hydro‑Québec defined a landscaping concept for the right‑of‑way with two objectives. The first is to encourage to use the right-of-way by including walking and bike paths, as well as urban furniture and plant beds in an attractive setting. The second is to preserve and enhance the biodiversity of the urban environment.

Hydro‑Québec, 2021 - Landscaping in the right‑of‑way.

In the past, this power line right‑of‑way was more of a field, where the vegetation was mowed a few times a year. Today, a grassy and shrubby territory extending over 42,000 m2, with some 700 trees and bushes and over 4,700 perennials, are an integral part of the landscape. Enhanced urban biodiversity, improved quality of life and active mobility were at the heart of the project, jointly designed by Hydro‑Québec and the city of Dollard‑Des‑Ormeaux. The development project provides an enhanced living environment which is beneficial for both humans and nature.

What to expect in the first few years

Some grassland seeds take two or three years to sprout. Some will make their appearance the first year, others the second or even third year after initial seeding. Most grasses and wildflowers only start to bloom after the second or third full growing season. So, patience is a virtue when you’re trying to create a meadow! Although the planting might look weedy for the first two years, many plants, wildflowers and grasses will start blooming in the third year. During the first few years, grassland perennials devote most of their energy to developing their root system. They won’t be very visible above ground the first year, but they’ll be working hard to grow deep, sturdy roots that will support them in years to come. The deep roots of wildflowers and grasses give them the strength over the long term to choke out annual and biennial weeds. Meadow plants come back in full force in later years, and for many decades to come.

To support urban biodiversity, native plant species were used extensively in the landscaping. Besides being just as esthetically pleasing as ornamentals, native plants are essential to maintaining our ecosystems. Because they evolved along with wildlife species, native plants are perfectly adapted to the animals’ needs. They play an integral role in maintaining biodiversity by providing food, shelter and breeding sites.

The landscape design is made up of a vast array of native species. Nearly half the plants are native and naturalized species, and most of those in the seed mixes used in the beds are native.

Plant choices were determined mainly according to the species native pollinators prefer. The aim was to enhance and protect the habitats that ensure pollinator development in urban environments. The plant species selected also provide good habitats for urban wildlife, including birds and some mammals. The horticultural varieties that grow on mounds and at intersections create blossoming sights for passersby.


Switchgrass, or tall panic grass, attracts butterflies and is a source of food for seed-eating birds like the American goldfinch. It also provides material for some bird species that build their nests on the ground.

New England aster

New England aster is a native plant known for its very high nectar yield, which attracts native bees and butterflies. It also produces seeds for birds, and shelters tiny insect larvae that overwinter in its capsules. The white-throated sparrow, common yellowthroat and chestnut-sided warbler are just some species that the New England aster attracts.

slender willow

The slender willow is a native shrub. Some bee species dig galleries in its soft wood to lay their eggs. It is also a source of pollen for foraging bees, including bumblebees.

The concept aimed to develop different landscapes that support wildlife and are adapted to the urban environment. It also established a biodiversity maintenance plan. Pollinators should thrive in the rights‑of‑way, and use them to find their way to other semi-natural environments, such as local parks and woodlands.

Monarch butterfly

Pollinators are linked to a number of ecological goods and services. For example, worldwide, they play a role in the cultivation of nearly 30% of the plants eaten by humans. They are also key to the health of natural ecosystems, since they pollinate wild plant species and thereby indirectly provide cleaner air and water, stabilize soil, and sustain many plant and animal species.

Pollinators are often associated with honey production, hives and honeybees, but there are actually some 350 bee species, including the native bee, honeybee and bumblebee, in Québec alone. Certain types of flies, butterflies and beetles also pollinate wild plant species, though less efficiently than bees.

Transmission line rights‑of‑way: areas suitable for pollinators

Transmission line rights‑of‑way constitute vast green spaces in urban settings, and that is why Hydro-Québec is concerned about the fate of bees. It is currently studying them to learn more about pollinators and the role transmission line rights‑of‑way could potentially play as habitats.

Research shows that rights‑of‑way are used by a wide variety of pollinators. The results of inventories conducted in urban environments reveal the presence of 90 pollinator species, including 40 in Montréal-area rights‑of‑way. What’s more, the plant species that grow in the rights‑of‑way meet the nutritional needs of pollinators during the three seasons in which they are active. Lastly, the presence of ground- and cavity-nesting species, particularly in the dead wood left behind following vegetation maintenance, indicates that rights‑of‑way are favorable habitats for laying eggs, finding shelter and overwintering. Transmission line rights‑of‑way therefore constitute habitats for native bees and are indeed essential in urban areas, where natural environments such as wildlands are rare.

The concept behind the various landscapes is closely tied to how the right-of-way will be maintained, which is through integrated vegetation management. Unlike the traditional method of mowing grass regularly and uniformly, integrated vegetation management aims to vary the frequency with which grassy areas are cut so a more natural green space can grow in order to foster biodiversity. Not only does the technique enrich the diversity of the plant and animal species, it also makes habitats more resistant to drought and invasive plant species. It enhances the quality of the landscape, making it richer, more diverse and more seasonal.

Following an integrated vegetation management approach, the landscaping concept for the transmission line right-of-way is rooted in creating a mosaic of modular spaces based on the frequency with which the vegetation is cut. Three mowing schedules are established, the areas of which are marked by stakes. So, these areas become habitats favorable to biodiversity in an urban environment.

The color code on the cap of each stake identifies the number of years between mowings and separates the various areas.

  • Orange stakes – These areas are mowed every two years. They support pollinators, such as monarch butterflies, honeybees, bumblebees and native bees.
  • Turquoise stakes – These areas are mowed every five years. They nurture amphibians and reptiles (e.g., the American toad, Dekay’s brownsnake, and redbelly snake).
  • Blue stakes – These areas are never mowed to nurture various small-mammal and bird species (e.g., red fox, yellow warbler, American goldfinch, song sparrow and American robin).

Monarch butterfly

Integrated vegetation management in transmission line rights‑of‑way has many advantages. Among them, it encourages the growth of species on which the butterfly feeds, enhances and protects the habitats in which it thrives, and increases monarch populations in urban environments.

Monarch butterfly

Buckthorn, a non-native invasive plant species (NNIS), was found on the site. This competitive plant can reduce biodiversity because it is highly adaptable. During landscaping, measures were taken to identify, remove and send off-site most of the buckthorn plants visible as well as their roots. This plant propagates through seeds from fruit that can accumulate in the soil and continue to germinate, despite efforts undertaken. Birds also play a role in spreading the seeds in surrounding areas by moving those present in the ground. Given the project objective of promoting biodiversity, rigorous follow-up will be done annually. Manual weeding will allow ongoing management of buckthorn on the site.


Hydro‑Québec effectuera des suivis environnementaux sur une période de 10 ans. L’objectif est de valider l’efficacité et la performance des mesures d’atténuation mises en place dans l’emprise. Ce suivi permettra à Hydro‑Québec de valider si la mise en place d’aménagements d’envergure en emprise est une mesure efficace et performante sur les plans de l’appropriation de l’emprise, de la gestion différenciée de la végétation, de la biodiversité et de l’accueil favorable des projets dans le milieu. Les résultats permettront de mieux baliser ces mesures d’atténuation pour les futurs projets, de développer divers outils de communication et de publications scientifiques établis sur les bases d’une démarche scientifique.

Investigation and survey

Among other things, Hydro‑Québec will conduct investigations and surveys of neighbors and users of the right-of-way. It could also document their use of the right-of-way and their perception of the landscaping done and urban biodiversity.

Natural environment plan

The environmental follow-up will:

  • Evaluate the integrated vegetation management and the performance of various seed mixes used (cost, benefits for biodiversity and the plant evolution of mixes)
  • Measure the effectiveness of the wildlife enhancement and maintenance method on preserving and improving biodiversity (areas seeded and planted)

Controlling buckthorn

Buckthorn is a non-native invasive plant species (NNIS). Hydro‑Québec will limit its propagation in the right-of-way and evaluate the effectiveness of some measures implemented for this purpose.