VERLOT – How to move a river?
This is what work crews faced this summer on the South Fork Stillaguamish River near the Gold Basin Campground.
The answer: lots of digging.
Workers demolished half of the sites at the still full campground next to the Mountain Loop freeway, tearing up concrete, fire pits and pit toilets. They felled hundreds of trees and dug a new 2,600-foot canal. Then, in August, they changed the river, like changing direction on a railroad track. As the water flowed, they caught and moved hundreds of fish – coho and juvenile chinook salmon, rainbow trout, sculpin, lots of whitefish, and a single bull trout.
To prevent sediment from sliding into the water, they built a series of barriers along the new channel using 1,600 logs. Behind them are a series of ponds separated by small dams. Over ten years, they will fill with silt. And the trees will grow, creating a new wetland-like environment that will continue to capture and filter silt.
The $ 5.3 million habitat restoration project to help endangered salmon species is a 20-year effort. This involved a partnership between the Stillaguamish Tribe, the Stillaguamish Watershed Council, and the US Forest Service, and required a lot of design and manpower. Anchor QEA, Anderson River Construction, based in Oso, Goodfellow Bros. and unionized workers contributed to the project.
The work is a balance between habitat restoration and recreation. Darrington District Ranger Greta Smith saw this as an opportunity to teach campers how we can help the environment.
Smith said the US Forest Service is working with the National Forest Foundation’s Treasured Landscape initiative to make improvements along the Mountain Loop Highway. She sees the Gold Basin project as a model for future efforts.
âThere is a lot of potential in this effort,â she said. “We’re not quite done yet.”
The project will help protect the river from the Gold Basin landslide, which for decades was the largest source of sediment in the river.
The hillside is made up of highly erosive clay, sand and gravel, the product of continental glaciers of more than 10,000 years ago, said Scott Rockwell, forest and fish biologist of the Stillaguamish tribe. . At the time, this area was under hundreds or thousands of feet of water, he said. The golden basin was part of a lake bottom.
The glacial soils were deposited in layers that can still be seen today from the campsite. After the glaciers retreated, the hill became exposed to the elements and prone to erosion. Each year, the hill dumped about 40,000 tonnes of sediment into the Stillaguamish, according to a US Forest Service environmental assessment released in 2018.
Landslides can be dramatic. In 1996, so much silt fell that it blocked the river, temporarily forcing it through the campground. And a few years ago, Rockwell said he found sediment on the campground, a sign of another major break in slope.
Studies show all that fine sand and silt is not good for fish, including endangered chinook salmon. It can clog gravel beds used for spawning, bury eggs, and suffocate baby fish. It can cloud the water, making it harder for fish to find food and can injure their gills.
The number of chinooks in the river is “extremely low,” according to a 2009 report released by Snohomish County. The Stillaguamish tribe had been trying to do something about the Gold Basin landslide for more than two decades, said Shawn Yanity, the tribe’s fisheries manager.
âWe’ve had a lot of ups and downs,â he says. “… It always seems like it’s more of a fight to do the right thing than to do the wrong thing.” ”
He said he wanted to see a viable salmon economy again. He wants there to be enough fish for everyone, both for the tribe members and for the sport.
âOur culture is disappearing with the salmon,â he said. “And that’s something that just isn’t acceptable to us.”