Restoring what’s been lost

Monitoring what matters 

How do we know if restored marshes are working? 

ProMEPP provides another opportunity for knowledge growth that supports the Restoring the Fraser River Estuary Salmon Habitat initiative, which is focused on monitoring biodiversity, measuring how fish, invertebrates and plant communities are responding in both natural and created marshes (this monitoring is ongoing). These insights help researchers understand what design features are most effective at supporting thriving ecosystems. 

Monitoring has already shown that many older marsh projects have lost their intended function over time, and sediment hasn’t always behaved the way we’d originally expected. This knowledge is crucial, as it points to the need for new, adaptive techniques grounded in how the river naturally works. 

Yet, even as marshes disappear in some areas, others are forming naturally. 

In places like Sapperton Bar, Tilbury Island and Annacis Channel, new marshes have appeared in recent decades thanks to natural sediment deposition (the settling of rocks and soils, transported in this case by water, resulting in new landforms). These places are excellent reminders that the river itself can teach us much about long-term marsh formation. 

But there’s a catch: many of these new marshes can be quickly overtaken by invasive species. 

Daniel describes how many of the “new marshes” in the Fraser are dominated by non-native species, particularly purple loosestrife, which can create hundreds of thousands of seeds per plant per year. “I see this as a reminder of the need for stewardship of these newly formed ecosystems. We have an opportunity to have a say in what they become, and that starts with being actively engaged in the process,” he says. 

Innovating with nature 

Inspired by these areas of marsh expansion, in 2024, ProMEPP launched a “pre-pilot” project at Tilbury Island with the goal of testing simple, low-cost methods of promoting marsh growth by working with the river, not against it. 

The team planted native sedges, some protected with goose exclosures to discourage unwanted grazing by Canada geese. They built a 10-metre brushwood dam made from stakes and bundles of branches, a method used to stabilize sediments in many regions of the world, and installed small timber pile dams. They also tested willow stakes at various elevations to see how they perform as living structures that could stabilize shorelines over time. 

These techniques were aimed to accelerate existing accretion processes, helping to build up mudflats until they can support healthy marshes. By installing “pre-pilots,” the ProMEPP team obtained valuable information that guided the design process for a larger, full pilot project.  

This pilot project is ready to launch, with Indigenous knowledge holders, scientists and restoration experts providing ongoing input. Construction began in February 2026.

What’s learned here could shape marsh restoration projects far beyond the Fraser.