Members of the research team assembled near the Willamette (photo courtesy of Olyssa Starry)
Whether it is safe to swim in the Willamette—and when—is a frequent topic of debate for Portlanders, but little is known about how people make decisions about going in the river. A pilot study by Portland State researchers is investigating how Willamette River water quality changes over time and how beachgoers decide when to use the river.
Beachgoers enjoying a sunny Portland day along the Willamette (photo courtesy of Olyssa Starry)Thanks to a $1.4 billion investment in the Big Pipe Project completed by the city of Portland in 2011, very little sewer overflow now makes its way into downtown sections of the Willamette, and E.coli in the water has remained well within levels appropriate for recreational use. However, potentially toxic cyanobacteria “algal” blooms continue to pop up along the river—as occurred in August from Cathedral Park to Willamette Cove. Microcystin, a toxin found in the cyanobacteria, can cause symptoms similar to food poisoning in humans and can be lethal to dogs when ingested.
PSU researchers Olyssa Starry, associate professor of urban ecology, and Jennifer Morse, associate professor of environmental science and management, have teamed up with Jennifer Morace, a hydrologist with the U.S. Geological Survey, to study how people's perceptions of the water quality of the Willamette compare to actual water sample measurements and how people decide when to swim in the river. Melissa Haeffner, assistant professor in environmental science and management, consulted on the project.
This pilot study is funded by a seed grant from the USGS-PSU Partnership (UPP), a longstanding collaboration between Portland State University and the U.S. Geological Survey (USGS).
“Catalyzing joint research is one of the UPP’s primary activities,” says Alison Hopcroft, partnership manager for the UPP. “Our seed grant program is a great example of collaborative research between our institutions that also engages students in the scientific process.”
USGS hydrologist Jennifer Morace collects sediment samples along the Willamette with PSU student researchers (photo courtesy of Olyssa Starry)Both Starry and Morse have experience studying stormwater management—practices that prevent pollution from entering our rivers and lakes—and this pilot study is giving them an opportunity to look at the effects “downstream” of this work.
“We've been working on all these things in the landscape that you can do to clean the water so that people can ultimately swim in local lakes and rivers,” says Starry. “Occasionally, it's good to look up and say, ‘is anything we're doing making a difference?’”
To see how water quality in the Willamette has changed and continues to change, the research team is synthesizing and analyzing historical water quality data collected by other organizations and taking their own water samples to measure microcystin concentrations at different points along the river. The team is also collecting sediment samples that Morace will analyze with the technical equipment in her USGS lab to look for metals and emerging contaminants.
Starry and Morse are looking for relationships between microcystin concentrations and other environmental variables like dissolved oxygen, nutrient concentrations and water temperature. The goal is to see if there are variables that can be used to predict when harmful cyanobacteria algae blooms are likely to show up.
The team is focusing their research on six popular recreational sites along the Willamette: Willamette Park, Poet’s Beach, Sellwood beach, Audrey McCall beach, Kevin Duckworth dock and Cathedral Park. Besides collecting water samples at these sites, the researchers are also surveying beachgoers about how they spend their time near the Willamette and how they evaluate when it is safe to go in the water.
Sediment sample collected from Poet's Beach (photo courtesy of Olyssa Starry)Morse says she’s been surprised by how enthusiastic people have been when questioned about their experiences with the river.
“Some people who have been swimming for years at these beaches have a really strong emotional connection to this activity in these places,” she says. “This is definitely, in terms of my career, the project where I’ve had the most direct interaction with people being passionate about what I’m doing. That’s pretty great.”
PSU students Arden Goldberg, Kaisa Holt and Michelle Hesek helped with the project by surveying beachgoers and taking water samples, all while gaining valuable job skills.
“They’re learning about communication, working as a part of a team, managing logistics,” says Morse. “These are really important professional skills that transfer to any discipline.”
After they finish analyzing their results, the researchers plan to share their findings with community partners the Human Access Project, which runs the Big Float, and Oregon Health Authority. They hope to have preliminary results this spring.
“We hope that this project is just the beginning of quite a bit more joint USGS-PSU Willamette River research in the future,” says Hopcroft. “The Willamette is a critical urban waterway, and UPP researchers are well-placed to study it.” Hopcroft notes that the USGS named the Willamette River Basin its fourth Integrated Water Science basin in March, which means it is being prioritized as a site of in-depth scientific study.
PSU student Michelle Hesek (photo courtesy of Olyssa Starry)Starry and Morse have already started thinking about possible follow-up studies. For starters, they want to know where the cyanobacteria algal blooms are coming from.
“There is this idea that they're coming from the Ross Island lagoon because that's where there tends to be blooms earlier and the conditions to foster those blooms, but if that were true then you would expect there to be blooms closer to Ross Island than Cathedral Park,” says Morse. “So something else is going on besides just proximity to Ross Island.”
A potential way to look at this could be to sequence the DNA of the cyanobacteria in different parts of the Willamette to see which populations of bacteria are related to one another and which are not.
Other insights could come from looking at the geomorphology of different beaches to see if some of them are more likely to host blooms due to having slow moving water or other characteristics.
Learning more about how cyanobacteria algal blooms form and spread in the Willamette could one day lead to more detailed guidance for Portlanders eager to splash about in the river.
“We might have policies that better inform the swimmers about the water quality more frequently,” says Starry. And that may make more Portlanders feel comfortable taking a dip.