This article was published on: 12/23/14 12:00 AM
By Jim Cornelius
Whychus Creek is slowly but surely “rewilding” to a state the first mountain men to trek across Sisters Country might recognize.
No longer do irrigation dams impede its progress. The once-dry creekbed in town now sees water flowing year-round. Through the Deschutes Land Trust’s Camp Polk Preserve, the stream once again winds and meanders as it did in days of old. In coming years, perhaps, steelhead will spawn in these waters.
Sisters Ranger District fisheries biologist Mike Riehle has worked on the district for 25 years.
“I never really dreamed that all of that was achievable, and I feel really lucky to be here for all of those pieces to come back together,” he said.
A wild future for Whychus Creek is not just a matter of letting nature take its course. It took a determined effort to begin to return the creek to a more natural state, and it took partnerships. Those partnerships include the Forest Service; Deschutes River Conservancy; the Upper Deschutes Watershed Council; the Confederated Tribes of Warm Springs; PGE; the Deschutes Land Trust; and a variety of private landowners, all of whom have worked separately and in concert to restore these waters.
Restoration required several steps. The first step – allowing for fish passage – is now complete, with the removal of the irrigation diversion at Pine Meadow Ranch. That move opened up an additional 13 miles of creek habitat. A new diversion point was created, along with more efficient irrigation systems that take less water from the creek.
“That whole change extends the water a little further downstream before it’s diverted, but also leaves a little more water in the creek,” Riehle said.
Channelization of the creek reduced fish habitat. Now, the creek is – with some human assistance – reestablishing natural flood channels.
“We’re going to hopefully raise the ground-water levels, as well,” Riehle said. “We’ve already seen that on the local level since we did that work this summer.”
More channels and more natural habitat give fish places to hide out during flood events, instead of being washed downstream in events such as the high water freshet that roared through Sisters last weekend.
“We’re already seeing the benefits of having multiple channels out there,” Riehle noted.
Floodplains are being created – some shaped by human intervention, some through the natural deposit of sediment.
“We built some floodplain islands out there, but we’re also seeing some of that natural deposition,” Riehle said.
Over time, there will be a lot of planting of riparian vegetation, such as willows and cottonwood. That provides both wildlife habitat and shade for the creek, making temperatures more amenable to fish survival.
It’s not just about fish. A wide variety of wildlife benefit from a wild creek.
“We’re seeing some goshawk activity,” Riehle said. There is other raptor activity as well – which is beneficial for humans, too.
“It’s kind of nice to have that right outside of town where people can enjoy it,” Riehle said.
2015 will bring some significant work on the creek. In April the Forest Service will undertake a logging project on two units adjacent to the creek. Wood will be placed instream to create habitat and the natural effect of log jams and clusters with channels weaving around them.
The projects will be “understory thinning,” Riehle said. “We retain all the overstory trees.”
In July the Forest Service will be placing trees in the creek and filling old ditches. That month will also bring the start of a project to replace the bridge at the old Brooks Scanlon Road. The span will be much broader – 125 feet.
“We’re going to open it up so it’s not as much of a pinch point in that floodplain,” Riehle said.
The long-term goal of reestablishing steelhead runs in Whychus Creek remains uncertain. Riehle says there is a pretty good survival rate for returning fish, but “the concern that we have is there’s not a ton of smolts leaving Lake Billy Chinook.”
Hopefully, there will be an increase in the number of smolts Whychus Creek produces.
Flooding like that which occurred last weekend is an ongoing issue.
“Part of the challenge of this creek is the flooding and what that does to reestablishing that riparian zone,” Riehle said. “We hope to retain some spawning gravel in that reach.”
Riehle was cautious about the prospects for improved flood control on the creek as it becomes more wild and natural. Multiple channels and more floodplain may delay and/or reduce peak flows, but that’s hard to measure.
“There are some benefits, ” he said. “We just don’t know how significant they will be.”
He noted that floods on the flashy creek tend to be quick – covering a 24- to 36-hour period.
“It’s really hard to have an impact on dissipating that short duration of a flood,” he said.
Returning Whychus Creek to a near-natural state is a long-term commitment. The interaction of so many interest groups, agencies and organizations to work toward that goal is exceptional and can be cited as a model for other such projects.
As a key player in the work, Riehle finds the cooperative effort inspiring and – given where things started – not a little astonishing.
“To see so much progress in this watershed,” he said, “…it’s remarkable.”