Search for climate corrections in Boundary Bay Marsh

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

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That’s the goal of the Boundary Bay Tidal Marsh Restoration Project, which will cost a six-figure sum, says Eric Balk, senior restoration biologist at Ducks Unlimited Canada.

Last Monday, the day that the project’s foundation stone was laid, Balk balanced on lichen and moss-covered logs piled up along the high tide line in Boundary Bay’s marshland. The land was swampy and brown, and a January cold snap had left puddles fringed with ice crystals.

Balk and I stand a stone’s throw from the dike that winds around the bay, preventing high water from flooding the nearby farmers’ fields and the golf course tucked away on the landward side.

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

Gray herons are listed as “of very high concern” under Canada’s Species at Risk Act. The stately birds grow to over a meter tall and forage mainly in freshwater and saltwater wetlands. Photo by Michelle Gamage.

Salt marshes are great carbon sinks, Balk says. They absorb carbon when salt-resistant grasses, bushes, and scrubby trees grow between the low tide and very high high tide marks. When plants die, the resulting plant matter is buried under silt brought in by the tides and other plants growing on it, he says, trapping planet-warming emissions in the muddy, reedy landscape.

Balk says you can see the riverside development while standing on the dike – there’s a low-lying farmer’s field on one side. On the other side is the swamp, which is higher than the field because the swamp has built up naturally in the decades since the dike was built.

Salt marshes also help protect communities from sea level rise and flooding, he says. When waves come in from the ocean, their power against the plants is broken. This reduces overflowing of the dike, which can happen, for example, when waves crash against a seawall.

Areas with salt marshes as an intervening ecosystem between land and sea are sheltered from storms, while places where the marsh has washed away are at risk of flooding, Balk says.

To help restore Boundary Bay’s tidal marsh, Ducks Unlimited Canada is removing logs washed in at high tide and stacked against the levee.

These logs, which are clean and smooth and look like phone polls, come from logs that were used to haul lumber down the Fraser River, Balk says. When the logs wash ashore, they tumble “like rolling pins,” crushing plants during different tides or storm events. Without spindly, uneven roots to ground them in the reeds, they easily pile up, suffocating the tidal marsh vegetation beneath them.

A small on-site team is identifying which logs have not been modified by human hands and should be left behind, and which logs cannot enter the Surrey Biofuel Facility. If a log has been treated with creosote or paint, or contains metal such as nails, it is collected by hand and stacked on a waste heap. Photo by Michelle Gamage.

With help from the federal fund Nature Smart Climate Solutions, Ducks Unlimited Canada will clear about 5,500 square feet of tidal marsh over the next month, says Balk. Maybe more — the clearing on day one of the project is going even better than the organization planned, and if the project goes like this continues smoothly, they may be able to cover more ground.

Restoring the Fraser River estuary wetlands benefits both animals and people.

The area is of “paramount importance,” Balk says. It is a Ramsar Wetland of International Importance and is the most important wintering site in Canada for waterfowl, shorebirds and raptors, he says.

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

The swamp is also home to the critically endangered Audouin tiger beetle, found only in Boundary Bay and Victoria in Canada, short-eared owls, which are listed as of very high concern in Canada’s Species at Risk Act, gray herons, also under the Species at Risk Act, and the pink-flowered Henderson’s checker mallow, listed as critically endangered by the province.

The nocturnal tiger beetle is often found in high salt marsh habitats that are also home to the Douglas aster, a perennial so ornamental it belongs in a garden, says Daniel Stewart, an independent plant ecologist who works with Ducks Unlimited Canada on the Boundary collaborates with Bay Project.

Stewart lifts a lilac-colored Douglas aster root from the disturbed soil where tree trunks have been removed — in the spring that root will grow into a new plant and hopefully attract the beetle to the restored area to thrive, he says.

Daniel Stewart, an independent plant ecologist (left) and Eric Balk, senior restoration biologist at Ducks Unlimited Canada (right), survey logs being cleared during the Boundary Bay tideland restoration project. Photo by Michelle Gamage.

Two previous projects involved transporting logs from the Boundary Bay swamp. Ducks Unlimited Canada helped with one in the 1980s and GCT Deltaport oversaw the other ten years ago, Balk says.

In the 1980s, the tree trunks were piled together and burned on the beach. This time they’ll be taken to the Surrey Biofuel Facility and turned into wood pellets that will be burned to fuel the town of Merritt, says Balk. A similar process, but with less wasted energy.

We also now know that the swamp can reseed to the point where you lose track of what used to be covered in logs and what wasn’t, says Stewart.

The restoration project will not be “vacuuming the swamp,” he adds — if a log has roots, it will be left behind. The roots anchor it in place to prevent it from rolling, and at high tide the timber, still anchored, can swing about and scour new puddles in the landscape.

After the swamp is cleared, only tree trunks are left with roots that act like anchors. These prevent the tree trunks from tumbling through the swamp like rolling pins and damaging plants during high water. Photo by Michelle Gamage.

Leaving behind some logs also leads to natural wave breakage during flood events, says Jeremy Venditti, a professor at Simon Fraser University School of Environmental Science, who was not involved with the project.

Venditti agrees that removing wood buildup and wood that has been pressure washed or creosote treated from the tidal marsh habitat helps the environment.

The marsh habitat could face increasing environmental stress in the coming years as the amount of sediment flowing down the Fraser River and into the estuary decreases, Venditti adds. That’s partly because there’s less mining in the Fraser Basin, and also because climate change has dried out BC’s interior, meaning fewer runoffs are carrying sediment down the river, he says. A loss of sediment could mean coastal erosion for the swamp habitat.

The Tyee also reached out to the Tsawwassen First Nation with questions about how they had seen the swamp damaged and what type of restoration projects they would like to see, but no one was available for interview.

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