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The City of Portland, Oregon

Environmental Services

working for clean rivers

Phone: 503-823-7740

Fax: 503-823-6995

1120 SW 5th Ave, Suite 613, Portland, OR 97204

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Lower Columbia Slough Refugia Engineered Log Jams

To create habitat for small migrating salmon, Environmental Services installed 35 engineered log jams along 9 miles of the Lower Columbia Slough. The slough’s quiet waters offer endangered steelhead, coho and Chinook salmon refuge from strong currents and predators in the Willamette and Columbia rivers on their migration to the Pacific Ocean. The new log jams will improve habitat without impacting existing natural resources or the slough levee.

Photo of log jams in the Columbia Slough

Image of in-stream wood

How do the log jams work? Because of past land use, there is very little in-stream wood in the lower slough. In-stream logs and rootwads slow water and trap woody debris. This provides juvenile fish places to feed, rest and find protection from predators as they migrate to the Pacific Ocean.

In addition, Environmental Services planted trees as part of this project to shade the slough banks. Shade from the trees cools the water and helps Portland meet Oregon Department of Environmental Quality (DEQ) targets for water temperatures. This improves the conditions for fish, who need cool water. Over time, these trees will become future in-stream logs.

This work is the latest in many Environmental Services’ projects over the years to protect water quality and improve habitat on the Lower Columbia Slough. Project funding comes from the Environmental Services Watershed Investment Fund and a DEQ Lower Slough Cleanup Fund grant.

Completed in 2015, the project earned a 2016 Achievement Award from the The Columbia Slough Watershed Council.

For more information about this or other Environmental Services projects in the Columbia Slough watershed, contact Jennifer Devlin at 503-823-1234 or