The lower Willamette River near Portland, OR experiences harmful cyanobacteria blooms nearly every year. Some blooms have led to public health advisories and animal mortalities. Cyanobacteria, also known as blue-green algae, can produce toxins that are hazardous to people and animals, especially dogs that drink or come into contact with affected water. Ongoing efforts to improve water quality in the lower Willamette have focused on addressing these recurring blooms by restoring river flow through Ross Island Lagoon where the blooms originate. This year, high temperatures and low river flow have created favorable conditions for an extreme bloom.

NOAA is supporting a research team led by Oregon State University in collaboration with the Human Access Project, Ross Island Sand & Gravel, and the Portland Kayak & Canoe Team. The team will monitor the bloom throughout the summer and use the data to create an extreme bloom scenario to model different management actions and engineering designs for bloom mitigation and prevention. The proposed restoration design includes one or two new channels that would restore river flow through Ross Island Lagoon and help prevent bloom formation. Data collection this year will help the team further refine the design and identify whether a second channel is necessary to prevent bloom formation during conditions that typically produce more extreme blooms.

The NOAA NCCOS HAB Event Response Program is a national program that provides immediate support to help state, tribal, and local officials manage HAB events and advance the understanding of blooms as they occur. For more information about the NCCOS HAB Event Response Program, contact nccos.hab.event.response@noaa.gov.
NOAA is authorized to respond to harmful algal bloom events under the Harmful Algal Bloom and Hypoxia Research and Control Act (33 U.S.C. §§ 4001 et seq.).
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