PORT ANGELES — Heavy loads of sediment and woody debris in a rain-swollen Elwha River are clogging filters and pumps at the Elwha Water Treatment Plant west of Port Angeles, Olympic National Park officials confirmed.

“Basically, they’re having to clean the filters a lot more frequently than anticipated,” park spokeswoman Barb Maynes said.

Drinking water is not being affected by the debris.

Port Angeles’ municipal water supply comes from a well near the river, not from the industrial water treatment plant that takes water straight from the river, Maynes said.

Water treated at the Elwha Water Treatment Plant, located 2.8 miles from the river mouth, goes to the Lower Elwha Klallam tribal fish hatchery, the state Department of Fish and Wildlife fish-rearing channel and the Nippon Paper Industries USA Inc. mill in Port Angeles.

Water leaving the treatment plant is well within standards, thanks to the efforts of crews, Maynes said.

“They’ve just been struggling keeping it maintained and on track,” Maynes said.

The Elwha Water Treatment Plant is operated by Veolia Water North America, one of several contractors involved in the National Park Service’s $325 million Elwha River restoration project that is keynoted by the removal of two dams.

A team of eight to 10 Park Service consultants and engineers was on site Monday and Tuesday making design modifications to the plant’s intake system.

“They’re trying to resolve it to get a permanent solution in place,” Maynes said.

The water treatment plant was designed to maintain fish-sustaining turbidity during removal of the Elwha and Glines Canyon dams.

Scientists have long known that removing the dams would trigger a large release of sediment that was stuck behind the dams in former lakes Aldwell and Mills for the better part of a century.

The anticipated sediment was the reason the treatment plant, fish hatchery and rearing channel were built in the first place.

“At this point, what I can tell you is that there have been some issues with the level of sediment and also organics — things like wood — working its way down the river,” Maynes said.

This debris caused a brief shutdown at the plant Sunday night. Workers have since been cleaning and monitoring filters, pumps and other equipment.

“It’s taking a lot more staff time and staff attention — and cleaning — to keep it operating,” Maynes said.

As of Tuesday, Maynes said there “haven’t been any problems” with the industrial water.

Nippon Paper Industries mill manager Harold Norlund was not immediately available for comment.

Maynes said the problem began “within the last week or so,” which coincides with a spike in river flows.

As river flows have ramped up, so have sediment and woody debris dislodged from the forest floor and reservoir beds.

Estimated river flows have soared from about 2,000 cubic feet per second last week to about 7,000 cfs over the weekend. The U.S. Geological Survey’s estimate for Tuesday afternoon was about 5,000 cfs.

Most of Glines Canyon Dam has been removed, allowing millions of cubic yards of silt, sand, cobble and gravel to flow over the top of what’s left of the former concrete high dam.

Elwha Dam was completely gone by March.

Dam-removal contractor Barnard Construction broke ground in September 2011 and expects to be finished with Glines Canyon Dam in May.

Maynes said it’s too soon to tell how fish are responding to the heavy sediment.

“Of course, it’s difficult to see them because the water is so muddy,” she said.

“There haven’t been very many collected at the hatchery. Lower numbers than last year are coming in, but that doesn’t mean they’re not out there.”

Reporter Rob Ollikainen can be reached at 360-452-2345, ext. 5072, or at rollikainen@peninsuladailynews.com.