Columbia Slough Watershed 

The Columbia Slough watershed is located in north and northeast Portland, Gresham, Fairview, Wood Village, Maywood Park and unincorporated Multnomah County south of the Columbia River. The watershed includes roughly 32,700 acres.

The Columbia Slough begins at Fairview Lake and meanders west for 19 miles to Kelley Point Park where it empties into the Willamette River. There are also about 30 miles of secondary waterways and other major surface water features such as Fairview Creek, Fairview Lake, and Smith and Bybee Lakes.

Historically, the Columbia Slough waterway was located in the floodplain for the Columbia and Willamette Rivers. Seasonally, the Slough and Columbia River would flood forming new wetlands and channels. To allow the watershed to be developed for agriculture, homes, and businesses, miles of levees were constructed. The waterway was channelized and dozens of streams were diverted from natural channels to underground pipes.