Capturing Carbon While Capturing Asbestos

The good news: our cleanup partner, Whatcom County Public Works, is making steady progress on its multi-year construction project to manage asbestos-laden sediment and control flooding in Swift Creek.

Even more good news: they’re also piloting a new technology to remove carbon dioxide from the atmosphere while making the sediment harmless.

There is a slow-moving landslide on the west side of Sumas Mountain near Everson that deposits naturally-occurring asbestos into Swift Creek.

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Carbon Creativity

Earlier this year, Arca Climate Technologies approached Whatcom County with a small-scale carbon removal research project using Swift Creek sediment.

Arca, a carbon removal environmental technology company, claims that the naturally occurring minerals in the sediment slowly reacts with atmospheric carbon dioxide (CO2) through natural weathering processes, resulting in long-term carbon storage. The research project will evaluate if amending and tilling, or “smart churning,” the sediment speeds up the natural atmospheric de-carbonization process.

Future Arca research projects could include proprietary methods to change the hazardous material, so that it pulls even more carbon from the atmosphere.

But for now, the landslide keeps moving and the construction project moves along with it.

Sediment Traps Work As Designed

In 2022, Whatcom County completed the first phase of sediment traps on Swift Creek. These traps are designed to slow down the creek so that larger, heavier sediment material drops out of the water in a basin behind a low wall. Once the basin fills with sediment, Whatcom County dredges the sediment and deposits it in the repository.

Before and after heavy rainfall

During a December 2025 heavy rainfall event in Whatcom County, the sediment traps worked as designed and stopped a significant amount of sediment from moving downstream—an improvement from earlier events such as the 2021 floods.

Ecology’s 2027-2029 biennium budget request includes the second phase of sediment traps.

A large project to capture the small material

Swift Creek construction plan, updated June 2026. The repository is labeled with red-hatching, and the sediment basins are outlined in blue.

The construction plan is to manage the sediment and control the flooding by slowing the creek down to collect the sediment and then having a place to safely store the asbestos-laden sediment in a repository. Download a PDF or a text explanation of the construction plan.

The construction elements planned for future biennia are large and require temporarily moving a portion of Swift Creek.

Managing Swift Creek’s sediment is much like running the creek through multiple “sieves.” The sediment traps further uphill collect the larger, heavier material and act as the first sieve while the last sieve downstream collects finer material in the sediment basins. Sediment from both the traps and basins will be regularly collected and deposited in the repository.

Ecology, Rep. Rick Larsen, and staff from Sen. Maria Cantwell’s office joined a September site tour hosted by Whatcom County Public Works, the Carbon Removal Alliance, and Arca Climate.

If the state legislature provides funding, in 2027-2029 the plan is to construct the first phase of the sediment basins. Environmental engineers will test how much of the smaller, finer sediment material settles out the creek. In order to build these test phase basins, engineers will realign the channel, which will also make room for the future large-scale sediment basins (Phase 3 is approximately 30 acres).

With continued collaboration and creative problem solving, a fully-constructed Swift Creek project will greatly reduce the asbestos-laden sediment in this transboundary watershed and perhaps help pull carbon from our skies - a win-win for the environment.