Marin County Pilots Innovative Dredging to Sustain Wetlands

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A pilot project in Marin County aims to test an innovative dredging technique that could help sustain local wetlands threatened by sea level rise. The plan involves using a small, shallow-draft dredging vessel to liquefy sediment in Gallinas Creek and allow the suspended particles to flow naturally into the nearby China Camp marsh, nourishing the ecosystem. This water injection dredging method has been used in larger ports, but this would be the first application in a tidal flood-control channel. The $640,000 grant-funded project is still in the design and permitting phase, but if successful, it could provide a new nature-based tool for managing sediment in tidal channels across the San Francisco Bay Area.

Why it matters

As sea levels rise, tidal marshes like the one at China Camp State Park are at risk of drowning unless they can be replenished with new sediment. This pilot project in Marin County explores an innovative, low-cost, and low-carbon dredging method that could help sustain these critical wetland ecosystems, which provide flood protection and habitat for endangered species.

The details

The pilot project planned for Gallinas Creek would use a small, shallow-draft dredging vessel to liquefy the built-up sediment by injecting water into the upper layers. This creates a turbidity current, a train-like cloud of suspended clay and silt particles that would then flow into the nearby China Camp marsh, allowing the sediment to naturally replenish the wetlands. The water injection dredging technique has been used in larger ports, but this would be the first application in a tidal flood-control channel. Regulators will likely require extensive modeling and monitoring to ensure the sediment plume does not cause unintended damage.

• The Gallinas Creek was last dredged in 1992, leading to a buildup of sediment that has made the creek shallow and stagnant.
• In March 2026, Marin County secured a $640,000 grant from the San Francisco Bay Restoration Authority to design and permit the water injection dredging pilot project.

What they’re saying

What’s next

Regulators may require extensive modeling and monitoring to ensure the sediment plume does not create unacceptable results, spread contaminants or damage habitat. Multiple agencies would likely review the project, including the U.S. Army Corps of Engineers, the San Francisco Bay Regional Water Quality Control Board and the San Francisco Bay Conservation and Development Commission.