Benefits of Urban Greening
Harnessing the Power of Plants
Montréal boasts 104 km of public riverbanks in municipal parks, 56 km of which are located in the large parks network. According to the city’s 2022 geomatic analysis of vulnerability to climate change, a high proportion of riverbanks along the Rivière des Prairies are vulnerable to flooding, with many reaching the “high” or “severe” degree of vulnerability. Several large waterfront parks are located along this river.
Certain areas are particularly vulnerable to increasingly severe spring floods, which can threaten public safety and infrastructure. Since 2019, 725 linear metres of walking trails in large parks have been rendered inaccessible for safety reasons, highlighting the urgent need to increase riverbank resilience in the face of climate change.
In 2021, Montréal launched the Riverbank Rehabilitation Program to restore 10 km of degraded riverbanks in large waterfront parks using bioengineering techniques to mitigate the erosion and enhance the various ecosystem services rendered by riverbanks.
In 2023, a mandate given to research and field experts confirmed the potential of phytotechnology for riverbank restoration under Montréal’s hydrological context. These nature-based engineering techniques, which mostly use plant material to reduce erosion and increase bank stability, are compatible with public safety requirements and adapted to local conditions, paving the way for their integration.
To put these findings into practice, a first pilot project was carried out in 2024 in the Secteur du Cap-Saint-Jacques within the Grand parc de l’Ouest, to provide insight for the design and construction of future projects.
Delivering Multiple Benefits
Designed as a learning opportunity, the pilot project allows for the testing of innovative nature-based techniques that are rarely used in Québec along large watercourses. Harsh climate conditions, the presence of ice, ice breakup and sensitive clays, as well as the legal framework all constitute challenges when it comes to bioengineering initiatives.
The Riverbank Rehabilitation Program aims to restore eroded riverbanks to protect users and park infrastructures, expand and diversify the ecological functions of riverbanks, and promote inclusive and responsible public access to water. The use of bioengineering techniques, which support biodiversity, protect aquatic environments, and mitigate the effects of climate change, also fosters tangible connections between people and nature.
Designers sometimes hesitate to adopt Nature-based Solutions, favouring more conventional engineering approaches that offer perceived predictability and immediate results. This attitude is in part attributable to a lack of information on the actual applicability of bioengineering techniques in similar contexts. Pilot projects such as this one play a crucial role in overcoming this barrier by demonstrating the effectiveness of phytotechnology and building confidence through tangible results and local evidence.
The pilot project and overall Riverbank Rehabilitation Program align with the strategic priorities of Montréal’s Plan climat (Climate Plan), Plan nature et sports (Nature and Sports Plan), and Stratégie de l’eau (Water Strategy). The pilot project is funded through Canada’s Disaster Mitigation and Adaptation Fund, in partnership with the Gouvernement du Québec, with a financial commitment from Montréal as part of its long-term planning.
The City’s Bold and Innovative Vision
Riverbanks are subject to various erosive forces, including water flow, waves, ice, run-off, and human activity. In a context where nature-based techniques are still marginal in Montréal, the pilot project offers a bold and truly innovative vision for ecological riverbank restoration. Unlike conventional approaches based on civil engineering and the use of inert materials, this project relies on living systems to stabilise soil, enrich biodiversity, and improve aquatic habitats.
Seven nature-based techniques were implemented, including large live stakes that help dissipate wave energy while promoting deep rooting and plant regeneration. Thirteen native species were carefully selected to restore the riparian community, including willow species less commonly used in riverbank restoration projects, such as Bebb’s willow, pussy willow, and shining willow, as well as helophytes to support fish habitats. This diversity creates a more resilient environment, whereas bioengineering projects often rely on a limited number of species. It allows assessment of each species’ potential for use at a larger scale.
This project also stands out for its deployment model. The Riverbank Expertise Centre was created within Montréal’s Large Parks, Mont-Royal, and Sports Department to support the City’s ambitions and ensure knowledge transfer across boroughs through a riverbank design guide. Scientific collaborations with researchers and professionals and knowledge exchanges with the nearby First Nation community of Kahnawà:ke enriched the process by contributing to a more inclusive and rigorous approach.
Partnerships and Collaboration
Due to a lack of knowledge and experience in bioengineering, an international team of researchers and bioengineering professionals was given the mandate to evaluate the applicability of bioengineering techniques to restore degraded riverbanks in Montréal’s large waterfront parks.
The pilot project brought together Monique Poulin, a professor of plant ecology at Université Laval, and André Evette, a researcher at Institut national de recherche pour l’agriculture, l’alimentation et l’environnement (the French National Research Institute for Agriculture, Food, and Environment) who contributed their expertise in conservation biology and bioengineering. Two professionals specialising in riverbank restoration in Québec and Alberta also helped identify exclusively plant-based techniques.
The city’s design team of the pilot project included a biologist specialised in bioengineering, a hydrogeomorphologist, and a landscape architect. The park management team actively participated in the on-site implementation and lent equipment necessary for the project.
Collaborations were also established with the geomatics department (drone documentation), the municipal tree nursery (temporary storage of the plants), and the communications department (interpretive signage).
Monitoring provides information on the efficiency of the various methods used in the pilot project. These results will be shared through expert exchanges and conferences, as well as public outreach activities, including with GUEPE, a local NGO specialising in environmental education and an active partner in Montréal’s large parks network.
Addressing Urban Challenges
The Issue
Riverbank erosion is a natural phenomenon, but when intensified by human activities (such as trampling and informal paths) and climate change, it can become a major issue for cities—especially Montréal, which is surrounded by water and bordered by both the Rivière des Prairies and the Fleuve Saint-Laurent.
In 2015, an audit of the riverbanks within Montréal’s large parks network raised serious concerns about citizen safety and environmental quality. Erosion-related damage included the undermining of pathways, collapse of retaining walls, uprooting of mature trees, slope degradation along roadsides, destabilisation of dock foundations, compromised access to water, and paving stones dislodged by erosion.
The historical flooding experienced in 2017 and 2019 generated significant erosion at several locations. In addition, most of the banks along the Rivière des Prairies were identified as vulnerable to flooding in Montréal’s 2022 geomatic analysis of vulnerability to climate change. Without intervention, these problems are expected to worsen with the increase in extreme weather events, with impacts on park infrastructure and potentially public safety, as well as the ecological value of the degraded banks.
Conventional bank stabilisation techniques, which rely on inert materials, are known to be resistant but potentially less resilient than Nature-based Solutions. Their ecological potential is also limited, and they can limit public access to water. This pilot project can provide evidence needed to foster the use of bioengineering techniques for riverbank stabilisation projects in Montréal and, more generally, in southern Québec.
The Impact of the Issue
Riparian zones act as buffers between terrestrial and aquatic environments and enhance the resilience of the neighbouring residential areas and the urban agglomeration. Waterfront parks are valuable due to the richness of their ecosystems and biodiversity, as well as their landscapes, which offer unique opportunities in an urban context to escape and enjoy a wide range of recreational and nature-based activities. There is a growing public demand for access to water, highlighting the importance of making riverbanks safe by preserving their long-term stability against erosion and degradation.
In 2019, approximately 725 linear metres of parkland were inaccessible due to degraded banks posing a public safety risk. The pilot project is in a flood-prone area that is closed to the public for several weeks each year during the spring freshet. In 2017 and 2019, water levels have approached the 100-year flood level twice, resulting in extensive flooding throughout the park, significant furniture damage, and widespread bank erosion, including tree uprooting, vegetation loss and destabilisation of heritage retaining walls.
The pilot project was designed to restore an eroded beach by enhancing fish habitat and restoring the bank with bioengineering techniques using native vegetation. It also contributes to building local expertise on the use of bioengineering techniques suited to Montréal’s conditions, with the intention of integrating these techniques into Montréal’s Riverbank Rehabilitation Program, and disseminating information throughout city departments and boroughs, and eventually with other professionals and municipalities.
Nature Positive Solutions
Implementation
The pilot project was initiated at the end of 2023 and was carried out entirely in-house in just eight months, including planning, budget approval, design, plant acquisition, and execution of the work. This is much faster than the usual project life cycle when dealing with external firms and shows that some small-scale projects can be conducted in a more agile manner than using the conventional approach.
Restoration work was carried out in June 2024, and frequent monitoring has been performed since then. After one year of growth, 74 per cent of the live stakes have survived, with sandbar willow and shining willow showing a particularly high survival rate of 91 per cent, especially in areas situated in the river. Once the vegetation is established, the riverbank can self-maintain through natural cycles such as plant succession and can serve as a model for future riverbank re-naturalisation projects.
In June 2025, furniture and educational panels were added in front of the pilot project, allowing park users to enjoy the view on the restored bank while raising awareness of flooding and nature-based restoration techniques.
Since its beginning, the project has delivered several positive outcomes for urban nature. This includes re-naturalising the shoreline with a variety of native plants, educating citizens on the benefits of riverbank restoration, building internal expertise, and fostering collaboration and interdisciplinary work across teams. The project also provides valuable feedback to City professionals on the applicability of bioengineering techniques for future riverbank restoration projects in Montréal.
Feasibility
The pilot project demonstrates strong feasibility, both financially and logistically, due to structured institutional support and strategic partnerships.
The objective of rehabilitating 10 km of riverbanks within the large parks network is a flagship goal of Montréal’s Plan nature et sports (Nature and Sports Plan) and Plan climat (Climate Plan). The Riverbank Rehabilitation Program is co-funded by Canada’s Disaster Mitigation and Adaptation Fund and the Gouvernement du Québec, and municipal funds integrated into Montréal’s long-term planning.
This cross-funding—secured until 2031—combined with the inclusion of the restoration target in various policy documents, including the newly adopted Plan d’urbanisme et de mobilité 2050 (Land Use and Mobility Plan 2050), ensures the initiative’s sustainability and its continued presence in public policy.
From a logistical standpoint, the pilot project relied on an interdisciplinary team composed of renowned researchers, bioengineering contractors, municipal experts, and collaborators such as the municipal tree nursery. This collective mobilisation guaranteed rigorous planning, design, and implementation. The inclusion of an educational component also allows the public to learn and stay mobilised for the protection of their riverbanks.
As the pilot project was conducted almost entirely in-house, costs were lower. Following the project’s implementation, monitoring was undertaken to gain knowledge on the efficiency and applicability of the various techniques used and the success of the overall project, as well as to perform corrective work if required.
Multi-Stakeholder Support
The Riverbank Rehabilitation Program responds to citizens’ desire for safe and high-quality access to water, as expressed in the public consultation report for the Grand Parc de l’Ouest (2021), and in the Water, Environment, Sustainable Development, and Large Parks Commission’s consultation report on the future of water (2024).
In relation to flood-related challenges, its importance has been evidenced in the past years with the exceptional spring floods of 2017 and 2019. Financial support granted by both the federal and the provincial government is also a strong demonstration of the strategic importance of this initiative.
The pilot project exists thanks to the collaboration of various internal teams. It was initiated by the City’s Riverbank Expertise Centre, based on the recommendations of the technical mandate conducted in 2023 and 2024 by a team of local and international bioengineering experts.
From the outset, the initiative’s design and implementation were discussed with the planning and operations teams at the Secteur du Cap-Saint-Jacques. This ensured that the pilot project was properly integrated in the park’s operations and long-term vision. As a result of this approach, all employees involved in the project are proud to have contributed to it and are committed to promoting it both internally and with the public.
A recent restructuring within Montréal’s Large Parks, Mont-Royal, and Sports Department has consolidated all planning teams working on parks and waterfront spaces. This has enabled the Riverbank Expertise Centre to expand and take on a more prominent role within the department.
Management and Maintenance
The pilot project was designed and implemented in response to the expertise report on the applicability of bioengineering methods to restore degraded banks in Montréal’s large parks. The report proposed nature-based interventions for the Cap-Saint-Jacques site, which will inform and strengthen Montréal’s Riverbank Rehabilitation Program.
Within this area, a 20 m section was identified as a priority for restoration as a pilot project. This was to enable the quick collection of feedback on the efficiency and potential large-scale application of the restoration techniques used, plant selection, the potential impacts of wildlife (including beavers) on the newly planted vegetation, and public perception of riverbank restoration through re-naturalisation.
To maximise the usefulness of the pilot project, a thorough monitoring programme was implemented in summer 2024 following restoration work and is planned to be continued over several years. This will significantly strengthen the initiative’s ability to document the project’s evolution and the effectiveness of the revegetation and bioengineering techniques used.
Frequent surveys are conducted by environmental and ecology specialists, including the collection of detailed data on plant regrowth and the impacts of flooding, waves, ice, wildlife and public use of the site (see Image 8). This monitoring both validates technical choices and allows for real-time adjustments to maximise success. Findings from this project will inform the design of future initiatives aimed at restoring typical riparian vegetation.
The team actively ensures the establishment of both planted and spontaneous vegetation, including watering during dry periods. Protective measures have also been implemented, including partial fencing of the site.
Measuring and Reporting Impact
Monitoring Results
The pilot project was designed and implemented by a team specialised in bioengineering, hydrogeomorphology, bank ecology and landscape architecture to ensure its effectiveness and long-term sustainability.
For over a year, thorough monitoring was carried out by a technician specialised in nature conservation, a landscape architecture technician, and a biologist specialised in bank ecology. This monitoring helps validate the performance of stabilisation techniques through the collection of detailed georeferenced data on plant survival and growth, as well as evidence of impacts from waves, ice, wildlife, and public use. Information on weather conditions, water levels, and the presence of waves or ice are also collected on each visit, along with georeferenced photographs.
Additional visits are conducted during major flooding, ice formation, or heavy rainfall, and the park’s management team also provides local assistance. A camera has been installed to document the long-term evolution of the site.
More than one year after the restoration work, the overall survival rate of live stakes is 74 per cent, and the willow fascines are firmly established over their entire length. Whereas establishment rates were limited for cuttings of red-osier dogwood and buttonbush, certain species—such as sandbar willow, shining willow, broadleaf meadowsweet and sweetgale—demonstrate strong regrowth. The planted vegetation has proven resistant to extended flooding and ice.
All collected data will be integrated into a riverbank restoration design guide for Montréal employees, a web platform intended to share lessons learned and encourage the adoption of bioengineering and nature-based techniques in future projects.
Demonstrating Progress
Initial indicators reflect the project’s success and the relevance of bioengineering and nature-based approaches in the Montréal area. This provides evidence that bioengineering techniques are effective in local riparian environments, offering an alternative to more traditional civil engineering methods (such as riprap and concrete walls).
These encouraging results have already generated interest within the City and will be shared through the upcoming bank restoration design guide. This web-based resource will include information on riverbanks and riparian environments, the regulatory framework, typical project steps and required studies, the erosional bank processes in Montréal, typical and recommended plant species, and design guidelines for restoration projects.
Lessons from the pilot project could inform all projects carried out under the Riverbank Rehabilitation Programme In addition, as the Riverbank Expertise Centre now offers technical support to boroughs, this knowledge will help in the design of other local projects.
The pilot project’s progress and success are also in the process of being shared with experts, government employees and stakeholders, including local communities and neighbouring First Nations communities. A broader communication programme will be rolled out in the coming years to inform citizens about upcoming work and raise awareness of the importance of re-naturalised riverbanks.
Measuring Impact
More than a year after the implementation of the pilot riverbank restoration project at Cap-Saint-Jacques, an initial evaluation reveals concrete results. The project’s impact is assessed both quantitatively and qualitatively, allowing for a detailed understanding of the effectiveness of the techniques used.
The overall survival rate of live stakes reaches 74 per cent, with outstanding performance from certain species such as sandbar willow and shining willow, which show a 91 per cent success rate in the littoral zone. Willow fascines (see Image 10) also demonstrate good regrowth along their entire length (4.5 m).
Other species, such as broadleaf meadowsweet and sweetgale, show strong establishment capacity, while some cuttings, including red-osier dogwood and buttonbush, had more difficulty taking root. This was due to the length of the cuttings and the state of some of the cuttings after a dormant period in the refrigerator.
The project’s monitoring programme documents the impacts of flooding and waves, erosion dynamics, and the effects of wildlife such as beavers, muskrats, and ducks. These observations enrich the understanding of how the installations behave under real-world conditions.
The pilot project also offers a concrete example of the re-naturalisation aspect of the Riverbank Rehabilitation Program. As such, it is being shared through expert networks and social media. The success of the pilot project has also motivated the undertaking of new pilot projects in two other parks to deepen understanding of certain techniques.
Learning and Transferability
Adaption and Enhancement
The design of the pilot project went through successive stages. Although it was initially focused on tackling erosion in a very specific area, its scope was soon expanded to various revegetation and bioengineering techniques, as well as to maximise the number of native species tested. At that stage, the supply of plants and stakes included a selection of a much wider variety of willows than are usually used in riverbank restoration projects. The park’s management team also provided insight into the design of the furniture included in the pilot project.
During the project’s implementation, stabilisation techniques and their location were slightly modified following discussions with the plant supplier. A willow weaving was proposed in the erosion notch instead of the willow fascine planned in the design phase, providing a better fit with the local topography. Several sweetgale specimens were also planted in the river to test their capacity to be implemented lower than usual in the bank profile.
Corrective work was decided based on monitoring visits. For example, it was observed that the fence installed to protect the plantings from beavers had been partially displaced by ice movement at the end of the winter and subsequently damaged by the public. It was therefore repaired on both occasions. In the absence of impacts from beavers, the fence will be removed sooner than initially planned. Corrective work is also being considered for the willow weaving, which has undergone some soil loss.
Potential for Replication
Following the success of the planning and implementation of the initial pilot project, two additional pilot projects were conducted in 2025 in other waterfront parks. The objective of these pilot projects is to evaluate the potential of implementing live stakes lower in the bank profile than in typical projects, as a means of dissipating wave energy and improving both bank and aquatic habitat.
Building on the approach of the first pilot project, all work was conducted in-house to speed up the process and minimise costs. Approximately 220 large live stakes from seven native species were harvested in a dormant state in parks from the island of Montréal, stored at the City’s tree nursery, and planted after the spring freshet. The live stakes were planted between the low flow and two-year flood water levels.
Despite some damage caused by the public and beavers, depending on the park, the establishment of live stakes has been very encouraging after a few months. Both projects will be monitored over the coming years to evaluate the applicability and effectiveness of this technique within the scope of Montréal’s Riverbank Rehabilitation Program, and eventually in other projects.
Finally, the pilot project has opened the door to a collaboration between the Riverbank Expertise Centre and the City’s tree nursery. The nursery was used for all three pilot projects to store plants and live stakes, and the possibility of producing plant material is currently being discussed.
Inspiring Other Cities
In the past two years, the Riverbank Expertise Centre has organised meetings with professionals from the cities of Laval, Longueuil, Vaudreuil, and Québec—four cities located along the Fleuve Saint-Laurent or Rivière des Prairies. These exchanges enabled the sharing of knowledge on best municipal practices for riverbank rehabilitation.
They have also helped establish initial connections between different teams with similar missions, facilitating collaboration on future riverbank restoration projects and providing opportunities to learn more about current and upcoming initiatives. The pilot project was presented and discussed during these meetings and was visited by representatives from Laval in autumn 2024.
From autumn 2025, the Riverbank Expertise Centre was expected to participate in a project titled Rooted for the Future: Bioengineering for Climate Change Adaptation, funded by Action-Climat Québec through the Fond d’action québécois pour le développement durable (Québec Action Fund for Sustainable Development).
This initiative aims to strengthen the use of bioengineering among municipal actors and other professionals to support climate change adaptation. Ultimately, it aims to promote the growth of these practices, mobilise a broad range of experts to encourage cross-sector collaboration, and enable better adaptation to climate change.
In addition, Montréal has registered its goal of rehabilitating 10 km of degraded public riverbanks in CitiesWithNature’s Action Platform—ICLEI’s international platform where cities can showcase their actions and how they contribute to global nature goals.
Resilience
Reducing Negative Impacts and Ensuring Sustainability
The pilot project incorporates several concrete measures to reduce its carbon footprint and ensure the long-term sustainability of its outcomes. By relying on bioengineering techniques, the project avoids the use of high-carbon inert materials such as concrete or rock, instead favouring naturally sourced solutions.
Plants are used not only to stabilise the bank, but also to contribute to carbon sequestration, thermal regulation, and surface water management, while fostering biodiversity and offering enhanced access to nature for the population.
Compared with conventional bank stabilisation methods that rely on the use of inert materials, bioengineering structures and Nature-based Solutions are more resilient. They become more resistant and provide more ecological services as they develop through time. The use of several techniques and native species is also an asset for the pilot project in terms of biodiversity and resilience.
Plant production is designed with a short supply chain in mind. A collaboration with the municipal tree nursery aims to use the current plants as mother stock for future local production, thereby reducing transportation and associated emissions.
Finally, the project’s resilience is supported by the reporting of key learnings and communication with the public via the furniture and information panels (see Document 5), as well as through conferences and social media.
Environmental Considerations
The anticipated impacts of the pilot project were integrated from the design phase, particularly thanks to its in-house implementation, which allowed for full control over technical decisions.
Plant selection was carried out in collaboration with a biologist specialised in bioengineering and a supplier with extensive experience in vegetation suited for riverbank stabilisation techniques. The selected species are native, resilient, and non-invasive, with a focus on plants that are endemic to the island of Montréal. Special attention was given to diversifying willow species, which play a key role in riverbank stabilisation but whose diversity tends not to be sufficiently taken advantage of in bioengineering projects.
Drawing on the knowledge of bioengineering experts and scientific references, the project included less commonly used species like Bebb’s willow and shining willow to evaluate their performance in a pilot project context. Plants were sourced from various regions of Québec to ensure genetic diversity and better adaptation to local conditions.
Water requirements were limited by planning the restoration work as early as possible after the spring freshet, and by watering the plants only during the first months after they were planted. Watering was done by hand using water from the Rivière des Prairies, reducing reliance on drinking water and minimising logistical needs related to transport.
The project’s in-house execution helped limit travel, reduce the need for heavy machinery, and lower associated energy consumption. Additionally, the wood used for the temporary installations was selected based on its durability and potential for reuse in future projects.
Use of Natural Resources
Bioengineering techniques are specifically implemented to reduce resource consumption by relying solely on cuttings from native shrubs that are well-suited to local conditions and require minimal maintenance once established. These cuttings were selected from areas near the project site and stored at the municipal nursery. The soil used for the project came from surplus topsoil from another project in the same area, and water from the Rivière des Prairies was used to irrigate the plants when necessary.
Ash wood from municipal parks has also been repurposed in this project. It is recovered from forested areas where dead ash trees were felled to ensure the safety of hikers, following the propagation of the emerald ash borer, an invasive pest species that attacks all species of ash tree. Stakes made from ash wood are used to anchor riverbank stabilisation techniques—such as willow weaving and fascines—and to build interpretive furniture.
By repurposing ash wood rather than turning it into wood chips, Montréal has achieved significant cost savings. This approach also allows for the carbon stored in the wood to be retained, helping to reduce greenhouse gas emissions that contribute to climate change.
Initiative: Restoring Montréal’s Riverbanks in a Changing Climate: A Strategic, Ecological and Social Commitment