Engineers Turn Dredged Sediment into Four New Islands to Test Salmon Habitat

During a routine dredging operation in October 2020, engineers moved 225,000 cubic yards of sand and silt from St. Helens Bar to the Washington bank of the Lower Columbia River, sculpting four small islands and a side channel known as the Woodland Islands. The new land, roughly seven acres, was seeded with compost and native vegetation, and natural river currents have since reshaped the terrain and introduced wild plants.

Scientists Brian Ekstrom and Lance Downing are conducting beach-seine surveys, mapping, and ecological assessments to determine how juvenile salmon and other wildlife use the artificial habitat compared with nearby natural sites. Parallel research is cataloguing baseline conditions at five potential future dredge sites slated for work beginning in 2027. If long-term data show meaningful benefits for salmon, the approach could become a model for habitat restoration across the Pacific Northwest, turning a necessary shipping-channel maintenance activity into an ecological asset.