Crooked River reborn

Oct. 15—ELK CITY — Crooked River has been freed from its decadeslong confinement, but it will be a few months before it can spread out and really "stretch its legs."

Come this spring, when mountains begin to shed snow, the river will swell just like it always has. But now the rushing water will be able to spill over its banks and run across its newly recontoured floodplain. Until recently the river was pinned between large tailings piles, a legacy of dredge mining, and separated from the rest of the river valley.

Some of that liberated snowmelt will sink and recharge the water table, enabling subterranean springs to seep into the river and keep it cool all summer long.

Some of it will carve side channels that provide habitat for juvenile salmon and steelhead, Pacific lamprey and amphibians like frogs, toads and Idaho giant salamanders.

Some of it will pick up dead trees and pile them in tangled log jams beneath which salmon, steelhead, cutthroat trout and bull trout will hide.

Some of it will pluck gravel from the floodplain and wash it back into the main channel where the current will sort it by size, creating spawning habitat for those fish.

And as the flood water recedes, some of it will deposit fine sediment and seeds in the floodplain. Trees like alders, cottonwoods and spruce, along with various native grasses and sedges, will flourish in the fecund soil.

Before long, the trees will be tall enough to shade the river and its side channels. Elk, moose and deer will browse on the nutritious leaves. Beavers will gnaw down some of the young trees, feasting on the bark and leaves and creating dams with the leftovers.

Legacy of destruction

Many of those natural processes haven't been possible since dredge mining that occurred between the 1930s and 1950s turned the narrow river valley upside down. The giant gold extracting machines left behind zigzagging, 20-foot-tall tailing piles that squeezed the river into an unnatural zipper-like channel known as the tortured meanders. When it did escape its banks, the water often was trapped in stagnant tailing ponds.

Over the past six or so years, the Nez Perce Tribe and Nez Perce-Clearwater National Forest have worked together to undo the devastating effects of that mining. On the lower 2 miles of the river, the tailing piles have been flattened, the ponds largely filled and a new channel created.

"We are doing this to kind of let the river be able to stretch its legs," said Jarrod Crow, project assistant for the Nez Perce Tribes Watershed Division, while pointing to the floodplain. "In the spring during the high flow, all of this should, hopefully, be inundated with high water, and we will get deposition of all these fine (sediments) that have been withheld for the last 70 years. Which is going to promote growth."

While the floodplain may look a little bare now, Crow said it won't stay that way. As evidence, he gestured downstream to a short stretch where the restoration work started earlier and the vegetation has had a two-year head start.

"You come back in two years, and it will look like that section down half a mile that is almost like a meadow right now. And with all the trees we planted, you won't recognize it."

Building nurseries

When people talk about the potential for dam breaching to unleash the salmon and steelhead productivity of the Snake River, they often cite the high quality, pristine or nearly pristine habitat found in many of its tributaries. Places like the Middle Fork of the Salmon River, the Selway River and much of the main Salmon River start in or flow through wilderness areas, and the habitat, while underused, is in excellent condition.

But there are places where it's less than ideal, where habitat projects can fix mistakes of the past. For decades, Crooked River, a tributary to the South Fork of the Clearwater, has been identified as such a place. The Bonneville Power Administration, which is seeking to offset damage done by Snake and Columbia river dams, funded the work. The Idaho Office of Species Conservation kicked in money from the state's share of the Pacific Coastal Salmon Recovery Fund, and the Forest Service contributed materials such as logs from nearby timber sales.

The $3 million project to unzip the river started in 2016 and, save for a short quarter-mile section, is largely done. Glacier Excavation out of Montana led the construction teams, which included local companies, as they first created a bypass channel — a temporary home for the river — and then flattened the tailings piles and constructed the main channel.

Last month, the river was pushed into its new path, and the bypass channel was filled. Project leaders held their breath as the water made its way downstream, following the path they created.

"When they first turned the water over, it took nine hours for the water to make its way from the top down to the bottom because it's just inundating the flood plain, soaking it in," Crow said.

Planting for the future

The work also included planting about 16,000 trees, shrubs and grasses, extensive seeding of native plants and the placement of logs, referred to as large woody debris, in the newly created channel. The river now gently meanders back and forth across the valley bottom. The logs will help keep the banks stable for a while. But the river eventually will chart its own course.

"We designed the channel to move over time," said Jenifer Harris, project manager for the tribe. "We are expecting it to be stable in the short term with all the large wood structures and all of the logs on the outer meander bends, but if it does move, that is what rivers do. We expect it."

Harris is keen on the potential of flood plains to create beneficial habitat. The project was designed to keep the floodplain low and give the river ample opportunity to mold the valley bottom into prime habitat for steelhead, chinook and other species.

"This is really a process-based restoration," she said. "We are just kind of resetting everything so it can start functioning again how river channels and valley bottoms should function."

The new river is more complex. It runs fast through riffles in some stretches but slows in others where sediment can fall out and create sand bars. On some turns, it can cut and scour, creating deeper pools, aided by the addition of logs.

"Before, it was all very homogenous, the same gradient through the whole thing," said Forest Service engineer Susan Graves. "So it ended up depositing the same exact size gravel and moving the exact same sized stuff. Now there is actually a variety of habitat within the channel itself, which is good."

Where rivers can interact with the floodplain there is more organic debris, more insect life and a broader diversity of aquatic organisms. Juvenile fish are able to escape high flows in the main channel. Overall, the fish are better for it.

"Those fish tend to be larger and more robust when the time comes for them to migrate to the ocean," Harris said.

Crow sees the project as building capacity into the system so it is a friendlier place for fish now but also ready should the tribe's desire to see the four lower Snake River dams breached, a long-discussed option, become a reality.

"We can only build habitat. We can't (address problems on the Snake River), there are other issues involved there," he said. "We are creating a nursery for them when they do make it back, and not just for salmon and steelhead but for lamprey and all the different species."

Barker may be contacted at ebarker@lmtribune.com or at (208) 848-2273. Follow him on Twitter @ezebarker.