Elwha gnaws away at a century of sediment

There’s more sediment and more wood than expected coming out of the Elwha River as the Elwha dams are taken down — causing more than a few surprises.

By Lynda V. Mapes, Seattle Times

Greg Gilbert / The Seattle TimesGlines Canyon Dam is two-thirds down, with the Elwha River pouring through the gap. Elwha Dam, 8.6 miles downstream, is already gone.
Greg Gilbert / The Seattle Times
Glines Canyon Dam is two-thirds down, with the Elwha River pouring through the gap. Elwha Dam, 8.6 miles downstream, is already gone.

A mother lode of mud is making its way down the Elwha River, and with it, an armada of floating and waterlogged debris.

Contractors are taking two dams out of the Elwha River as part of a watershed and fishery recovery project that is the largest of its type ever in the world. The first, Elwha Dam, came out a year ago. Glines Canyon dam is about two-thirds gone.

Scientists recently learned there was about 41 percent more sediment trapped behind the dams than originally thought — and that the river is transporting more mud and wood than they expected.

As the river, dammed for 100 years, comes back to life, the other surprise is a forest of waterlogged wood and other organic debris the Elwha is muscling out of the former lake beds of the reservoirs.

All that wood is interacting with the sediment in the river with unpredictable results, said Andy Ritchie, restoration hydrologist for the National Park Service, which is running the Elwha recovery project. He was surprised this winter to see the river building fences and jams of wood that trapped sediment in places where it wasn’t expected, such as at Elwha Campground, or causing erosion in others, such as at the historic Elwha ranger district.

There have been other surprises.

Dam removal was put on hold last October until contractors make more than $1.4 million in emergency retrofits to the new $71.5 million Elwha Water Facilities plant.

It was built as part of the dam-removal project, to clean sediment from the water supply to an industrial pulp and paper plant, a fish-rearing channel and a hatchery. But the plant failed during the first fall rains last October, when fish screens and pumps became clogged with leaves, twigs, branches and sediment.

What the total cost to the project of the breakdown will be — on a plant that was already the single most expensive piece of the $325 million Elwha restoration — and what caused it to fail are still being sorted out, said Barb Maynes, spokeswoman for the park service.

The agency hopes to get contractors back at work taking down Glines Canyon Dam by mid-April. Meanwhile, taxpayers are paying $245,000 to contractor Barnard Construction for the project delay (on top of the repair costs, paid to contractor Macnac Construction of Lakewood) while the water plant is fixed.

Contractors are taking the rest of Glines Canyon Dam down ten feet at a time, and only three whacks remain. The park service still expects to complete dam removal by September 2014, as originally planned.

But even with dam removal on hold, restoration is not standing still.

After a 100-year hiatus, the Elwha is back at work moving sediment, carrying some of it all the way to the river mouth, where a whole new world is emerging.

Surveys both by airplane and by an underwater video camera show a kelp armageddon is under way. The amount of floating kelp at the river mouth and east to the Ediz Hook has already been reduced by 44 percent in the year since dam removal began, said Helen Berry, marine ecologist at the state Department of Natural Resources.

Underwater video also shows a dramatic shift on the sea floor, with a transition in one year from lush pastures of seafloor plants to a war zone of tattered vegetation and large areas nearly denuded.

The reason is sediment. It is blocking light in the water column, and smothering the rocky seafloor with soft mounds of fine material transported by the Elwha, making it unsuitable for the holdfasts which kelp species need to affix themselves to the seafloor.

But scientists think the kelp’s demise is a gain for other species, in a reset of the nearshore ecology to a more normal state. Old maps show no kelp at the river mouth and east to the Ediz Hook.

The accretion of soft sediment is expected to provide habitat for sea grasses that nurture salmon, said Anne Shaffer of the Coastal Watershed Institute in Port Angeles. Soft, sandy beaches also could provide spawning grounds for a chrome tide of sea smelt and sand lance.

“I see it as a return to how things are supposed to be,” Shaffer said. “And we are only at the beginning of these ecological effects.”

Closest to the river mouth, the resumption of the river’s delivery of sediment is also hoped to slow erosion that has claimed up to 100 feet a year in some parts of the tribe’s reservation, east of the river.

Just how much of a difference will be made long term isn’t known, especially when, in about 10 years, the amount of sediment the Elwha delivers annually resumes to its new normal.

But for now, at the river mouth the results are dramatic as the river plays catch-up, gnawing at 100 years of entrapped sediment, and moving it out to sea.

Jonathan Warrick, a scientist at the U.S. Geological Survey Pacific Coastal and Marine Science Center at Santa Cruz, Calif., is helping to map a new sand spit that has formed at the west side of the river mouth. It’s already about one-third of a mile long, and growing.

“I thought it would happen this year,” Warrick said. “But I am a little blown away at how big the bar is.”

Pink Salmon Broodstock Spawned to Protect Elwha Run

Lower Elwha Klallam Tribe hatchery technician Keith Lauderback sorts through pink salmon eggs at the tribe’s hatchery.
Lower Elwha Klallam Tribe hatchery technician Keith Lauderback sorts through pink salmon eggs at the tribe’s hatchery.

Source: Northwest Indian Fisheries Commission

Pink salmon are the most abundant salmon species in the Northwest, but the Lower Elwha Klallam Tribe didn’t want to risk losing the Elwha River pink population with the current removal of the river’s two fish-blocking dams.

The deconstruction of the Elwha and Glines Canyon dams are part of the massive project to restore the Elwha River after nearly 100 years of blocked flows and degraded salmon habitat. One result of the project is that high levels of sediment once trapped trapped behind the dams are now flowing downriver.

“We weren’t sure how the pinks were going to be affected by the dam deconstruction activity, so we wanted to take precautions to protect them,” said Larry Ward, the tribe’s hatchery manager. “The historical population of pinks in the Elwha River was 400,000 to 600,000. The current run is 200, making it a chronically depressed stock of fish.”

While pinks have a lower commercial value, they play an important role in a properly functioning ecosystem by providing food for other animals and contributing nutrients to the watershed.

“The habitat in the lower river for pinks wasn’t great when the dams were in place, but they were using it,” Ward said.

Pinks returning to the Elwha River in 2011 were collected and spawned. The fertilized eggs were incubated at the Washington Department of Fish and Wildlife’s (WDFW) Hurd Creek Hatchery, then sent to the National Oceanic and Atmospheric Administration’s (NOAA) Manchester Research Station, where they were reared to adults. The fish, 300 males and 132 females, were then brought back to Elwha in August for spawning.

A portion of the fertilized eggs from this fall’s spawning will go back into the pink salmon broodstock program, while the rest will be reared to smolts and released from the Elwha Hatchery into the river in spring 2014. The broodstock program is expected to continue through the 2015 pink salmon cycle.

The tribe’s partners in this program are NOAA, WDFW, Olympic National Park, Northwest Indian Fisheries Commission and citizen volunteers.