Port Angeles City Council hears update on Elwha River sediment

By Jeremy Schwartz
Peninsula Daily News

PORT ANGELES — Olympic National Park personnel gave City Council members an update on the millions of cubic yards of sediment coursing down the Elwha River at Tuesday’s council meeting.

The presentation did not address the sediment clogging the Elwha Water Treatment Plant, built about 2.8 miles from the river’s mouth, and the plant’s surface water intake, collectively referred to as the Elwha Water Facilities — and council members didn’t ask questions about it.

Tuesday’s presentation followed a meeting last Thursday between the staffs of the city and the park in which city officials, including City Manager Dan McKeen, were briefed on the sediment problems plaguing the Elwha Water Facilities, which could affect the city’s water.

Mayor Cherie Kidd said Wednesday that the Tuesday presentation “met expectations” and that the information helped improve communication between the city and park.

“It’s another step in the process,” Kidd said. “I thought it was an excellent step in the process.”

McKeen said Wednesday a national park staff presentation to the council on the Elwha Water Facilities could be expected in the near future, though no date has been set.

“At some point in the near future, it would be anticipated that a presentation will be made to council that will include the national park and an update on the [Elwha Water Facilities],” McKeen said.

“If you think about it logically, at some point, we really need to do that.”

Sediment in plant

Since fall, sediment released during the teardown of the Elwha River and Glines Canyon dams begun in September 2011 as part of the $325 million Elwha River restoration project has unexpectedly been finding its way into the treatment plant.

That has prompted the need for repairs on two separate plant areas: the backup water intake and the pump station that takes water from the intake into the plant itself.

All repairs are on hold, however, while the pump station repairs are designed.

Park spokeswoman Barb Maynes said last week that Tuesday’s presentation was meant only to update City Council members on the amount of sediment that has floated down the river since last year, when a national park staff gave a similar presentation to the council.

During the meeting, park hydrologist Andy Ritchie told council members 20 percent of the estimated 34 million cubic yards of sediment that had built up behind both dams while they were standing has flown down the river so far.

“The sediment transport, or the erosion of reservoir sediment, has been within the modeled predictions,” Ritchie said.

Monitoring data

Monitoring data show the river has eroded roughly 5.5 million cubic yards of sediment since last October from the former site of Lake Mills, once held back by the 210-foot Glines Canyon Dam, Ritchie said.

That’s about 20 percent of the total 28 million estimated to have built up behind the dam, which has since been cut down to 60 feet.

“We only expect a fraction of that, between 50 [percent] and 70 percent, to erode,” Ritchie said.

Roughly 1.3 million cubic yards of sediment has eroded since last October from the former site of Lake Aldwell, which the now-demolished Elwha River Dam once held back.

Ritchie said continued monitoring will allow park staff to more accurately tally additional sediment flows and will help the project’s manager determine when removal of Glines Canyon Dam, on hold since October, can begin again.

In a letter to Creachbaum in March, McKeen said park staff were not keeping the city in the loop about the water facility problems, which are causing the city to rely more heavily than expected on its Ranney Well, the main source for city water.

As part of the staff meeting last Thursday, park staff assured city staff communication between the two entities would continue as the water facility repairs are made.

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Reporter Jeremy Schwartz can be reached at 360-452-2345, ext. 5074, or at jschwartz@peninsuladailynews.com.

Last modified: May 08. 2013 5:42PM
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