Wetland restoration or construction for flood resilience

Wetland restoration or construction involves creating or rehabilitating wetland areas to manage stormwater, absorb floodwaters and improve water quality. These projects increase community resilience by reducing downstream flooding, supporting biodiversity and providing natural buffers against extreme weather events. In small and rural communities, wetlands offer a low-cost, multi-functional solution that protects critical infrastructure, agricultural lands and local ecosystems.

This guidance outlines key steps, best practices, costing information and case studies to help municipalities plan and deliver wetland restoration or construction projects.

Key steps for successful implementation

• Identify potential wetland sites: Use local floodplain and watershed maps to inform decision-making
• Centre local priorities: Engage with Indigenous communities, local organizations and landowners to integrate local knowledge and values
• Conduct site assessments: Determine soil, hydrology and vegetation conditions
• Define project objectives: Set clear goals, such as flood risk reduction, water quality improvement and habitat restoration
• Get your paperwork in order: Seek required permits and approvals from environmental and municipal authorities

Best practices for design and delivery

• Use native plant species: Select species suited to local conditions to improve ecosystem resilience and reduce maintenance needs
• Minimize disturbance: Limit impacts during construction and prevent sediment runoff into adjacent waterways
• Leverage resources across organizations: Coordinate with local agencies for ongoing maintenance and ecological monitoring
• Incorporate an educational component: Raise awareness about wetland functions, flood mitigation and ecological benefits

Equity and community considerations

• Prioritize engagement with Indigenous communities: Consult with local First Nations to respect traditional land use and knowledge and to gain a better understanding of the project site
• Engage farmers early in planning: Consider impacts of the project on agricultural lands and livelihoods
• Balance accessibility with safety: Consider designing wetlands to support community recreation and public interaction while minimizing risks

Costing and budgeting information

Wetland restoration and construction projects can cost $50–$200 per square metre depending on site size, conditions¹ and complexity.

Typical cost drivers include excavation, liner materials, vegetation and maintenance.

To help reduce overall costs:

• Transplant nearby native plants to reduce landscaping expenses
• Leverage community volunteers for planting and monitoring efforts; provide honoraria where appropriate, particularly for small organizations or equity-deserving communities
• Select sites² with natural depressions or existing wetland features to minimize excavation needs

Case studies and lessons learned

Collaborative planning to restore tidal wetland and reduce flood risk (Truro, NS, 2021)

The Nova Scotia government, in collaboration with researchers, industry partners, local landowners and Millbrook First Nation, breached sections of an existing dyke along the Salmon and North rivers to allow tidal waters to return to the floodplain, gradually restoring the area to a tidal wetland ecosystem. The project included channel excavation, construction of new dykes where necessary, and extensive pre- and post-restoration monitoring.

Lesson learned: Coordinated planning across multiple stakeholders, including government, researchers, Indigenous communities and local landowners, ensures that flood risk reduction, ecosystem restoration and community priorities are successfully integrated.

Constructed wetland delivers environmental, social and economic benefits (Loyalist Township, ON, 2020)

To address elevated pH levels in the effluent from the Amherstview Water Pollution Control Plant, Loyalist Township built a constructed wetland using locally available cattails to naturally treat wastewater. Beyond improving water quality, the wetland reduces flood risk, provides habitat for waterfowl and shorebirds, creates accessible green space for residents, and reduces long-term operating costs (compared with mechanical UV treatment).

Lesson learned: Constructed wetlands can simultaneously reduce flood risk, improve water quality, create habitat, provide community green space, and lower operating costs. This demonstrates the value of multi-benefit nature-based solutions.

Wetland restoration transforms schoolyard into habitat and outdoor classroom (Quadra Island, BC, 2022)

Quadra Island Elementary School, in partnership with the B.C. Wildlife Federation, School District 72, and the We Wai Kai First Nation, restored a historic wetland on the school’s sports field to improve stormwater management and create habitat for native plants and animals. The project included excavation of shallow basins, native plantings funded by an EcoAction grant and volunteer support from local community members.

Lesson learned: Wetland projects can go beyond simple community engagement by providing opportunities for residents to play active roles throughout the project’s delivery. Thoughtful consideration of education and hands-on learning experiences, especially for youth, can foster a sense of ownership and community pride.

*Note: The case studies included on this page are for informational purposes and were not supported by the Green Municipal Fund.

Additional resources

Road impact wetland health assessment (RIWHA) tool (B.C. Wildlife Federation) – This field-based assessment tool helps identify and prioritize wetlands impacted by roads and linear infrastructure, combining scientific indicators with local knowledge. A separate, streamlined version of the tool supports fieldwork in remote areas.

Compendium of resources (Invasive Species Centre) – Invasive species removal can be a co-benefit in a wetland restoration process. This comprehensive resource summarizes invasive species education, outreach and management tools, organized by species and pathway of spread. It helps agencies and community groups coordinate communications, adopt best practices and integrate materials into their own programs.

Biodiversity mapping and assessment tool (Ducks Unlimited Canada) – This tool identifies biodiversity hotspots to guide conservation and restoration efforts. The public version currently provides data for the Prairie Ecozone, showing predicted species richness of amphibians, birds, mammals and reptiles. A similar tool is being developed for Eastern Canada.

Explore more flood resilience activities

Learn about other flood resilience project types and how they can support your community:

• Stormwater ponds
• Permeable pavements

Return to the Flood Resilience Toolkit for Municipalities

Related toolkits

GMF offers additional toolkits to support municipalities facing different climate risks. 

• Heat Resilience Toolkit
• Wildfire Resilience Toolkit
• Community Facilities Toolkit

Glossary

Biodiversity hotspot: An area with high species richness or abundance that is a priority for conservation and restoration efforts

Constructed wetland: A human-made wetland designed to mimic natural processes for purposes such as flood control, water treatment and habitat creation

Floodplain: Low-lying land adjacent to a river or stream that is prone to flooding during high water events

Invasive species: Non-native plants or animals that can cause ecological or economic harm in new environments

Stormwater management: Practices that control the quantity and quality of runoff from rain or snow, often to reduce flooding and improve water quality

Tidal wetland: Wetlands influenced by tidal movements, providing habitat and natural flood mitigation in coastal areas

Wetland: An area of land that is saturated with water either permanently or seasonally, supporting aquatic plants and wildlife

Select resources

1. Landowners-Guide-Wetland-Restoration-Ontario-2022.pdf

2.Wetland Vulnerability Metrics as a Rapid Indicator in Identifying Nature-Based Solutions to Mitigate Coastal Flooding