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Columbia Slough Watershed Council

Our Watershed

Our Watershed

The Columbia Slough is a 60-mile long remnant of lakes, wetlands and slow-moving channels, that were formerly floodplains connected to the Columbia River.  The Slough wetlands and waterways were home for millennia to Native peoples, namely the Upper Chinook, as it provided abundant and diverse fishing and hunting opportunities, and safe canoe passage. Today, the ceded land now known as Portland, is home to the nation’s ninth largest urban Native American population.


In the early 1920’s levees were constructed to prevent seasonal flooding and the waterway was transformed into the channeled and highly managed system now known as the Columbia Slough. With the elimination of yearly floods farming, industrial and residential development flourished.

Today the 40,000 acres of watershed contains 24,000 homes, 4,500 businesses, and is home to 1/10 of all the jobs in Multnomah County.

Each year more than 13.7 million people and over 275,000 tons of freight come through the watershed. Impacts from 150 years of development have left a legacy of environmental problems in the Slough: contaminated fish and sediment, diminished wildlife habitat, and water pollution from both point and non-point sources. The Columbia Slough Watershed Council was formed to address these issues.

As habitats are modified throughout the Portland metropolitan region and the entire Northwest, the Slough’s importance as a component of our regional system of greenspaces grows. The Slough is one of the largest urban waterways contained wholly within the metropolitan urban growth boundary. This vast ribbon of habitat and openspace can be explored by foot, bicycle or canoe and kayak.

Flanked on the west by the 2,000 acre Smith and Bybee lakes, and on the east by the 102 acre Fairview Lake and the headwaters of Fairview Creek near Grant Butte in Gresham, the 60 mile Slough and its watershed represent an irreplaceable resource, both for the region and for north and northeast Portland, Gresham, Fairview, Troutdale, and Wood Village.

Nuestra Cuenca

La cuenca del Columbia Slough es una red de 40 millas de humedales, pantanos, lagos y canales de la antigua llanura aluvial del rio Columbia.  Esta cuenca de 50 millas cuadradas capta los escurrimientos y agua subterránea que la rodean y es rica en recursos naturales. 

La cuenca sustenta a numerosas especies de peces, aves, y vida silvestre, y provee importantes funciones ecológicas: mejorar la calidad del aire y agua, proveer drenaje y ayudar a controlar las inundaciones. Este es un lugar bello para la contemplación, recreación y el descanso.

Resource Description
Portland Bureau of Environmental Services
Environmental Services is Portland, Oregon's Clean River agency. The agency treats Portland's wastewater, provides stormwater drainage services, and works in Portland watersheds to reduce stormwater pollution, restore native vegetation, and improves the quality of water in our rivers and streams.
The City of Portland Water Bureau
The City of Portland Water Bureau operates a well field capable of producing close to 100 million gallons per day. The Columbia South Shore Well Field is the second largest water source in the State of Oregon, with about half the capacity of Portland’s Bull Run source.
Groundwater Protection Program Brochure
City of Portland; Portland Water Bureau Groundwater Protection Program Information
Center for Columbia River History
Explore the history of the Columbia Slough and its communities. View the images and read the documents that tell about slough's past. Listen to the voices and read the oral histories of those who witnessed a transformation from farm to city, and of those who created diverse social, environmental, and industrial communities.