PORT ANGELES — Elwha River sediment released by dam removal that is overwhelming the Elwha River Treatment Plant could create an “extremely serious” situation for Port Angeles’ water supply, the city manager says.
The sediment clogging the intakes of the plan could lead to a shortened lifespan of the well from which Port Angeles gets most of its water, City Manager Dan McKeen said.
City officials don’t know enough about what the National Park Service is doing to fix the problem and wants to be kept advised, McKeen said in a letter sent to Olympic National Park Superintendent Sarah Creachbaum.
The city’s water supply is not in danger, Public Works Director Glenn Cutler said Friday.
The primary source of municipal water, called the Ranney well, and the Port Angeles Water Treatment Plant are continuing to filter water to federal water quality standards, he said.
“There’s been no health risk or concern associated with the quality of the water being delivered,” Cutler said.
McKeen said in his letter that “Any action that impairs or jeopardizes the functioning of the Ranney well is extremely serious.”
“[The treatment plant issue] has the ability to cause the premature failure of the Ranney well, which [would] affect the city’s ability to provide drinking water to [its] residents,” McKeen said Saturday.
Creachbaum said Friday the park service is considering how best to respond to the city.
“Because of the sensitivity surrounding the issues currently, we’d first like to just have a discussion with the city manager’s office and then respond in [a] letter,” Creachbaum said.
Creachbaum said the Park Service’s response letter would most likely be developed in the next week or so.
“I believe that the park has been making every effort to cooperate with the city, and as we go forward, the National Park Service will continue to cooperate with the city,” Creachbaum said.
McKeen said he had an “immediate response” from Creachbaum about the city’s concerns and will be meeting with her soon.
“I had a call back from [Creachbaum], and we are getting together to discuss [the issue],” McKeen said.
The clogging of Elwha Treatment Plant water intakes is forcing the city to rely more heavily on the Ranney well than originally intended, McKeen wrote, something the National Park Service built the plant to avoid.
“The Elwha water facilities were the key to the plan to protect the Ranney well,” McKeen wrote.
“It was acknowledged that operating the Ranney well during periods of high sedimentation would lead to clogging, resulting in abrupt failure of the well or significantly shortening its operating life.”
The Ranney well, built in the 1970s on a side channel of the Elwha, collects both surface water and water from an underground aquifer below the riverbed, Cutler explained.
Since last fall, the Elwha Water Treatment Plant and the Elwha Surface Water Intake Structure, collectively called the Elwha water facilities, have not been able to provide as much pre-filtered river surface water to the Port Angeles Water Treatment Plant as originally planned, McKeen wrote.
According to the Congressional act that started the unprecedented Elwha River restoration project, the Elwha water facilities were built to protect the city’s water supply from the fine sediment the Park Service knew dam removals — which began in September 2011 — would release into the river.
The Elwha Water Treatment Plant specifically was designed to filter surface water to no more than 20 NTUs — or nephelometric turbidity units, a measurement of water clarity — and send it to the city’s water treatment plant, which was built as part of the $325 million Elwha River restoration project.
The city treatment plant, in turn, would filter the water so it could be used by city residents.
Less surface water is being sent to the city treatment plant then expected, however, because the Elwha treatment plant cannot filter enough of it, city officials said.
Before the city’s water treatment plant was built in 2010, the Ranney well served in a water-filtering capacity and still does, Cutler explained.
Cutler would not comment, however, on what would happen if the Ranney well were to become compromised and had to be shut down, as he said abrupt failure is not a concern at this time.
“I don’t answer hypotheticals,” Cutler said.
Park spokeswoman Barb Maynes said the Elwha Treatment Plant water intakes have been stopped up with woody debris, forcing treatment plant staff to work nearly around the clock to keep the screens clean.
To address the Elwha treatment plant clogging issues, the Park Service has inked a $1.4 million contract with Lakewood-based Macnak Construction to replace the current screens, which were cleared with bursts of air, with new ones that will be mechanically cleaned.
The screen replacement work should be done by mid-April, Maynes said.
Finishing the removal of the Glines Canyon Dam also has been put on hold while the screens are replaced and work continues on figuring out why the Elwha water facilities are not behaving as planned.
“We don’t yet have a complete understanding of the issues,” Maynes said. “We’re still working on that, and we’re continuing on it until we get the answers.”
Demolition of the Elwha Dam was finished a year ago, with the takedown of both dams proceeding ahead of schedule.
Scientists studying the Elwha restoration project have said the river has already moved some 6 million of the estimated 34 million total cubic yards of sediment that built up behind the once-towering dams.
Earlier this year, the National Park Service revised the total amount of sediment expected to come down the river from 24 million cubic yards after a century-old surveying error was discovered.
________
Reporter Jeremy Schwartz can be reached at 360-452-2345, ext. 5074, or at jschwartz@peninsuladailynews.com.
