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New interactive map advises recreationalists of HABs dangers

July 20, 2022

The McKenzie River is one of Oregon’s best recreation destinations and here in Eugene we are lucky to have it right in our backyard. Whether you paddle, swim, or fish, you can find clear, crisp waters with stunning scenery throughout the McKenzie Valley.

There are a few sites, however, that pose higher risks for developing Harmful Algal Blooms. HABs are outbreaks of toxic cyanobacteria that thrive in warm water conditions, and they can be harmful to human health or to pets.

As the McKenzie River is currently the sole source of drinking water for around 200,000 people in Eugene, EWEB routinely tests water in 10 locations to be able to detect and treat for the effects of HABs to make sure our water is safe to drink.

It’s been a part of our water quality regime since the Oregon Health Authority began requiring cyanotoxin monitoring in 2018. In the four years EWEB specialists have sampled for cyanotoxins, we have never detected toxins at concentrations of concern at the Hayden Bridge Water Treatment Plant intake site.

Map of EWEB algal toxins monitoring sites

Nevertheless, in the warm summer months, people should be aware of HABs and learn how to identify suspicious algae to stay safe. Parents and guardians of young children and dog owners should pay particular attention when swimming in or near the Blue River Reservoir or downstream of Cougar Reservoir. At these sites, the reservoirs’ impounded water can heat up and accumulate nutrients, creating ideal habitats for HABs to develop. 

The Oregon Health Authority recommends, "Don't go into water that looks foamy, scummy, thick like paint, pea-green, blue-green, or brownish red. A good rule of thumb for you and your pet is: When in Doubt, Stay Out!"

EWEB is making it easier for you to recreate safely, with a new interactive HABs map that displays our latest testing results. By providing early warning of when cyanobacterial HABs are producing cyanotoxins, we can help prevent  potential recreational exposure to these cyanotoxins in our reservoirs and river.

“We collect hundreds of samples every summer, and we keep a watchful eye on the McKenzie,” said Water Quality Specialist Brenda Casarez. “We’re excited to share our testing results on our new interactive HABs map so we can help EWEB customers and visitors stay safe when exploring our beautiful McKenzie River.”

HABs website

Next time you’re heading up to Blue River or Cougar Reservoir, check out our website to get a heads up on HABs activity. Be sure to check the date of the test, as we monitor every two weeks, and use your best judgement if the water doesn’t look healthy.

Learn more about HABs and EWEB’s Water Quality Monitoring

Harmful Algal Blooms: Frequently Asked Questions