City study says ‘dangerous’ low-head dam should be removed from Willamette River

An engineering firm has recommended a full removal of an underwater dam in the Willamette River, according to the results of a study commissioned by the city of Eugene.  

The dam, a structure that helped power waterwheels in a bygone era of energy infrastructure, sits low in the river just east of the Interstate 5 bridge between Eugene and Springfield.

Eugene Public Works department announced in a press release Wednesday, Oct. 28, the results from a draft of its Millrace Low Head Dam Feasibility Study completed this month.

“The Millrace Low Head Dam, which has been in the Willamette River for more than 100 years, is a dangerous obstacle that routinely threatens the safety of river users and has caused several near drownings,” public works spokesperson Marion Suitor wrote. 

The feasibility study launched this year with a $50,000 budget. In June, contractors Dowl Engineers sailed a small survey boat through the dam, navigating it with a handheld controller from the shoreline. They measured the elevation of the riverbed, capturing data for models that evaluate how water flow would change — both upstream and downstream — if the dam is altered or removed.

The study examined three alternatives for removing or modifying the concrete dam and an associated rock weir near it, Suitor told Lookout Eugene-Springfield in a follow-up email.

One alternative was dropped, because it did not meet the project’s main goal of increasing safety, Suitor said.

Two alternatives remain:

• Full removal of both the concrete dam and the rock weir
• Removal of only the concrete dam

In the draft report, the engineering firm recommends full removal, Suitor said.

The study estimates both solutions at $4 million to $5 million. 

City staff, representatives from Dowl Engineer, and partners from American Rivers will share the results of the study in full during an open house Nov. 9.

American Rivers, a nonprofit focused on river restoration and dam removal, started partnering with the city of Eugene this summer.

“Like all low head dams, the Millrace dam poses a significant public safety risk,” said Sarah Dyrdahl, Northwest regional director for American Rivers, in the press release.

“Every year, people swimming, tubing, and paddling on the Willamette go over the dam and become trapped in the recirculating current downstream. We are grateful to the City of Eugene for engaging in this work to consider removing or modifying the dam before more people are injured or killed,” she said.

For years, local groups and advocates have pressed government agencies to address the dam. The now-defunct Chambers Power Co. sold it to other companies, which abandoned it at least 75 years ago. 

It is not clear whether the cities of Eugene, Springfield or another government agency has responsibility for it.  

In an interview with Lookout Eugene-Springfield, Dyrdahl said last summer was a turning point, in part because Lookout published a series of articles documenting worsening turbulence from the eroding dam and hotter summers drawing more swimmers to the river.

Meanwhile, this year, Willamalane Park and Recreation District posted official warning signs at three put-in locations about the dam and “high risk of drowning.” However, the sign does not represent an acceptance of responsibility for the low-head dam. The same goes for the city of Eugene and its feasibility study. 

At this point, the feasibility is informational and does not commit the city to any action, according to Suitor and her department. 

“We went into the study with the goal of increasing safety while ensuring river integrity,” said Rachael Vaicunas, a principal civil engineer with Eugene Public Works. “The alternatives Dowl identified were measured against that requirement, and we’d like the community to understand the factors and conclusions related to that outcome.”

Community open house 

• 5:30 to 7:30 p.m. Monday, Nov. 9 
• Bascom-Tykeson Room, Eugene Public Library, 100 W. 10th Ave., Eugene