Beavers play an important role in salvaging Central and Eastern Oregon watersheds that have been ravaged by decades of logging, ranching and other harsh land uses. Sometimes, they need a bit of encouragement to return to a stream.
Volunteers with the Oregon Natural Desert Association have spent the week working alongside workers with Heart of Oregon Corps in a mostly dry river basin within the Pine Creek Conservation Area, hauling dirt, cutting down willow branches and hammering 6-foot-long wooden posts to construct dozens of structures that simulate the flow of beaver dams.
These structures, known as beaver dam analogs, slow the flow of water, helping native plants and animals flourish and, conservationists hope, create environments that will encourage beavers to return to Pine Creek and build dams of their own.
“If (the dams) survive long enough, the beavers may start using them,” said Sam Vanderbeek, crew leader for Heart of Oregon Corps.
Jefferson Jacobs, riparian restoration coordinator for ONDA, said having beavers return could create enough dams to saturate the once-verdant valley.
“They’re the real restoration engineers, and everything that we do is to enable them to do their stuff,” Jacobs said.
Beaver once lived throughout the Columbia River Basin, and, as in other parts of the West, trapping reduced their territory. When settlers moved into the area near Pine Creek in the 19th century, they found a section of river bereft of beavers. Subsequent decades of cattle grazing and other land management practices left the area with a small, eroded creek near the edge of an otherwise-dry river basin. Jacobs said having beavers in the area to slow the flow of water in the creek would have mitigated some of the damage.
“The land was in really poor shape; it had been used pretty hard,” he said.
Jacobs added that the loss of beaver and the subsequent degradation had a trickle-down effect on other plants and animals in the area. By slowing down the river and raising water levels along the banks, they allow creekside vegetation like willows to crowd out invasive plants that have sprouted in the area.
Moreover, Jacobs said they make the surrounding land wetter and spongier, allowing it to soak up water that stays underground. This underground water tends to be cooler and more hospitable to native fish like steelhead, redband trout and spring chinook salmon.
“Every dam is like a spring installation,” Jacobs said.
The lack of water also has an impact downstream in the John Day River. Jacobs said low water levels in its tributaries contribute to low flows in the river during the summer months. The flow during early September can drop below 150 cubic feet per second, compared to more than 10,000 during the spring, according to data from U.S. Geological Survey.
While beavers can help, Jacobs said the animals need certain conditions, including a mix of flowering and wooded vegetation and an abundance of water, to thrive. Much of Pine Creek and nearby Cove Creek did not fit that description.
“This is a pretty inhospitable spot for beaver,” Vanderbeek said.
The land was purchased by Bonneville Power Authority around 2000, and Jacobs said ONDA has been involved in restoration work on the parcel for about a decade. Volunteers have pulled out barbed wire and planted willows along the creek, but building beaver dam analogs has become a priority.
To construct a dam, workers carve and sharpen logs from pine trees into 6-foot-long posts, placing about a half-dozen in a line along a section of creek. Workers from Heart of Oregon Corps, which spent an extra week prepping the site by building poles, then use a hydraulic post pounder — a jackhammer-like machine that holds one side of a post in place and hammers it into the ground — to place them. From there, volunteers will weave in branches from willows and fill the area with dirt and rocks to slow the water down.
Joe Wheaton, a geomorphologist at Utah State University, said one advantage to beaver dam analogs over other types of stream restoration is that they doesn’t require tons of heavy equipment, making it easy and rewarding for volunteers.
“They’re great opportunities for gratification,” Wheaton said. “People see things happen quickly.”
In some parts of the basin, they’ve seen results. The organization placed 15 beaver dam analogs along the creek in 2015, and beavers from other parts of the basin moved in and built their own dams in between, helping to create a small oasis of willows and cottonwoods along the river.
“The whole creek should look like this, and this isn’t even done,” Jacobs said. “This is just starting.”
Jacobs noted that beaver dam analogs can be controversial, as some researchers question their impact on fish passage. Still, Wheaton said those concerns are overblown when considering their impact on native fish, which evolved in systems with beaver dams in place.
The approximately 20 workers participating in the project each see different benefits from the work. For the crew working for Heart of Oregon Corps, a program that provides vocational training and continuing education opportunities to Central Oregonians between the ages of 18 and 24, the work provides an opportunity to achieve certifications and present a body of work to agencies like the U.S. Forest Service and the Bureau of Land Management, Vanderbeek said.
For the ONDA volunteers, the work provides a way to give back and stay active. Craig Terry, a retired volunteer, said he’s been volunteering for around a decade.
“It’s fun to come out and work with a group of people that all have a common goal,” Terry said.
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