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Environmental Services

working for clean rivers

Phone: 503-823-7740

Fax: 503-823-6995

1120 SW 5th Avenue, Suite 1000, Portland, OR 97204

Questions and Answers

Willamette River in PortlandDoes Portland still have combined sewer overflows?

Yes. A large part of the city has a combined sewer system that carries sewage and stormwater runoff in the same pipes. All the combined sewage and stormwater drained directly to the Willamette River and Columbia Slough until the city built the Columbia Boulevard Wastewater Treatment Plant (CBWTP) in 1952.

Portland's first sewage treatment plant improved water quality. But when it rained, stormwater runoff filled combined sewers and caused combined sewer overflows (CSOs).

When Portland began its 20-year CSO control program in 1991, there were an average of 50 CSO events per year.

In October 2000, the city completed projects that reduce CSOs to the slough by more than 99%.  In December 2011, the city completed the last in a series of projects that reduced CSO volume to the Willamette River by 94%. With the new system, there will typically be no more than an average of four Willamette River CSOs per winter and one every three summers.

Can I swim in the Willamette River?

Even though CSOs are less frequent now, there is still bacteria in the lower Willamette River from many sources, especially during wet weather when the river is high. You can check for current CSO alerts at www.portlandonline.com/bes/riveralert or 503-823-2479.

Portland HarborSince Portland completed its CSO control program in December 2011, more people are enjoying the river when the weather is good. The annual Big Float is a good example.

Even though Willamette River bacteria levels are low during dry weather, it's never safe to swallow water from urban rivers and streams.

Click here to read an Oregon Department of Environmental Quality fact sheet about Willamette River swimming safety.

How does the Portland Harbor Superfund site affect water quality?

The Portland Harbor Superfund site extends roughly from the Willamette's confluence with the Columbia Slough to the Broadway Bridge. The U.S. Environmental Protection Agency (EPA) declared Portland Harbor a Superfund site because of chemical contamination in sediments on the river bed.

A 2011 report by the Oregon Health Authority's Evironmental Health Assessment Program (EHAP) stated that boating, swimming and other forms of recreation in the Portland Harbor area is not a threat to human health.

Can I eat fish from the Willamette River?

Fish that live year-round (bass, carp, catfish) in Portland Harbor have high concentrations of polychlorinated biphenyls (PCBs). In 2004, the Oregon Health Authority issued an advisory recommending special precautions and restrictions on eating resident Portland Harbor fish. Click here to read the advisory.

The advisory does not apply to non-resident fish (salmon, steelhead, lamprey) that travel through the Portland Harbor area.

Click here for more information about fish in the Willamette and fish consumption guidelines.