Urban watersheds are complex systems that rely on strong partnerships to balance development needs with natural resource management and protection. In the Columbia Slough, Portland’s most urbanized watershed, there’s a long history of seeking this balance, and a recently discovered photo reflects how much has changed.

Until 1918, the Columbia Slough was connected to the Columbia River floodplain. The annual water would carve slough channels and fill up lakes and wetland areas. In the summer, the Columbia floodplain would dry out. The flood waters were unpredictable and made the land along the Columbia difficult to cultivate and develop. 

This photo was taken one hundred years ago at the place along the Columbia River where flood water overflowed into the head of the Columbia Slough.  The site is along present-day N.E. Marine Drive.

After this photo was taken, a levee system was constructed to prevent floods from entering the area, which enabled farmers to plant crops and industries to develop along the Columbia Slough channels.  The levee also provides protection for the Portland International Airport.

This photo was taken on November 2, 2017 to show the changes at the head of the slough over the last 100 years. The levee obscures the view of the Columbia River, the banks of the Columbia Slough have been vegetated with native plants, and the pump station in the photo was built to move water from the Columbia Slough out to the Columbia River

Within the levee system, however, the Columbia Slough boasts the most wetlands in Portland and an amazing variety of fish and wildlife, including salmon that are protected under the Endangered Species Act. That’s why Environmental Services and partners like the Columbia Slough Watershed Council and the Multnomah County Drainage District work together to improve the health of the Columbia Slough by keeping the water moving to allow cold spring water to flow in, and by planting the slough channels with water-loving native plants such as willows and dogwood. Those plants create shady cool spots for fish and wildlife.

To learn more about watershed improvement projects along the Columbia Slough, check out https://www.portlandoregon.gov/bes/32202

To help with Columbia Slough stewardship projects or to explore the slough by boat or foot https://www.columbiaslough.org/

To learn more about the levee system http://www.mcdd.org/  or http://www.leveereadycolumbia.org/