Finding Climate Fixes in the Boundary Bay Marsh

Fighting climate change and helping coastal communities adapt to rising sea levels doesn't always have to come with a multimillion-dollar price tag. In some cases, the solution can be as simple as clearing logs from a tidal salt marsh.

That's the goal of the Boundary Bay Tidal Marsh Restoration Project, which will cost closer to six figures, says Eric Balke, senior restoration biologist with Ducks Unlimited Canada.

Last Monday, the day the project broke ground, Balke was balancing on logs speckled with lichen and moss heaped at the high tide line in the Boundary Bay marsh. The land was boggy and brown, and a January cold-snap had left puddles fringed with ice crystals.

Balke and I stand a stone's throw from the dike that winds its way around the bay, which prevents high tides from inundating nearby farmer's fields and the golf course hidden on the landward side.

Between us and the ocean stands the tidal marsh, a vital part of the Fraser River estuary and recently discovered tool in the fight against climate change.

Salt marshes are big carbon sinks, Balke says. They absorb carbon as salt-resistant grasses, bushes and scrubby trees grow between the low to very high-tide mark. When the plants die, the resultant plant material is buried beneath silt brought in by the tides, and by more plants as they grow on top, he says, sequestering the planet-warming emissions in the muddy, reedy landscape.

Balke says you can see the foreshore buildup while standing on the dike — on one side is a low-lying farmer's field. On the other is the marsh, which sits higher than the field because the marsh has been naturally built up in the decades since the dike was built.

Salt marshes also help protect communities from sea level rise and flooding, he says. As waves come in from the ocean the force of them is broken against the plants. This reduces dike overtopping, which can happen if waves splash against a seawall, for example.

Areas that feature salt marsh as an intervening ecosystem between land and the ocean are protected during storms, while places where the marsh has been washed away will be at risk of flooding, Balke says.

To help restore Boundary Bay tidal marsh, Ducks Unlimited Canada is removing logs that have washed in at high tides and piled against the dike.

These logs, which are clean and smooth and look like telephone poles, have escaped from log booms used to transport timber along the Fraser River, Balke says. When the logs wash up on shore, they tumble “like rolling pins” and crush plant life during different tides or storm events. Without scraggly, uneven roots to ground them in the reeds, they easily pile together, smothering tidal marsh vegetation below them.

Using the federal Nature Smart Climate Solutions fund, Ducks Unlimited Canada will be clearing around 5,500 square metres of tidal marsh over the next month, Balke says. Perhaps more — clearing on the project’s first day is going even better than the organization has planned, and if the project continues this smoothly, they may be able to cover more ground.

Restoring Fraser River estuary wetlands benefits animals as well as humans.

The area is of “superlative importance,” Balke says. It's a Ramsar Wetland of International Importance and the single most significant location in Canada for overwintering waterfowl, shorebirds and raptors, he says.

Just ask any of the birding enthusiasts who flock to the Boundary Bay dike, armed with camera lenses as long as your arms and each with their own strategy to keep warm as they sit for hours in the blustery, exposed landscape.

The marsh is also home to the endangered Audouin’s night-stalking tiger beetle, which is only found in Boundary Bay and Victoria in Canada, to short-eared owls, listed as of special concern under Canada's Species at Risk Act, to great blue herons, also listed under the Species at Risk Act, and to the pink-flowering Henderson's checker-mallow, listed by the province as critically imperilled.

The night-stalking tiger beetle is often found in high salt marsh meadow habitats that are also home to Douglas aster, a perennial that's so ornamental it belongs in a garden, says Daniel Stewart, an independent plant ecologist working with Ducks Unlimited Canada on the Boundary Bay project.

Stewart scoops up a lilac-coloured Douglas aster root from the churned earth where logs have been removed — in the spring this root will grow into a new plant, hopefully attracting the beetle to the restored area so it can thrive, he says.

Two previous projects hauled logs out of the Boundary Bay marsh. Ducks Unlimited Canada helped with one in the 1980s and Vancouver Fraser Port Authority oversaw the other a decade ago, Balke says.

In the '80s, the logs were piled together and burned on the beach. This time they'll be taken to the Surrey Biofuel Facility and turned into wood pellets to be burned to fuel the city of Merritt, Balke says. A similar process, but with less wasted energy.

We also now know the marsh can re-seed itself to the point where you don't know what used to be covered with logs and what didn't, Stewart says.

The restoration project will not be “vacuum cleaning the marsh,” he adds — if a log has roots attached, it'll be left behind. The roots anchor it in place to prevent it rolling and at high tide the wood, still anchored, can swing around and scour new puddles in the landscape.

Leaving some logs behind will also create natural wave breaks during high tide events, says Jeremy Venditti, a professor at the Simon Fraser University School of Environmental Science, who was not involved with the project.

Venditti agrees that removing wood buildups and wood that has been treated using pressure washing or creosote from the tidal marsh habitat will be helpful for the environment.

Marsh habitat could face increasing environmental stress in the coming years because the amount of sediment flowing down the Fraser River and out into the estuary is decreasing, Venditti adds. This is in part because there is less mining in the Fraser Basin, and also because climate change has been drying out B.C.’s Interior, which means less runoff carrying sediment down the river, he says. A loss of sediment could mean coastal erosion for the marsh habitat.

The Tyee also reached out to the Tsawwassen First Nation with questions about how they had seen the marsh damaged, and what kind of restoration projects they'd like to see happen, but no one was available for an interview.