Wetland restoration is a success

It's a warm afternoon as smoke from a distant fire settles into the tree canopy. Black Butte's faded silhouette overlooks the 50-acre Black Butte Lower Swamp, which is experiencing renewed life. Willows and waist-high, vibrant-green blades of sedge drift in the caustic breeze. Birds whisper among the treetops. Indian Ford Creek, once subtle, now ripples through the meadow.

This once-barren landscape harbors abundant life, once again.

The faint aroma of native mint fills the air as Mike Riehle, the fisheries Biologist for the Sisters Ranger District, hikes the swamp overlooking the results of last year's efforts.

"It was not this lush last year," he says, pointing to the vegetation around him while carefully stepping through the rejuvenated terrain. "A lot of willows were fading, the birches were struggling, and there were dead patches everywhere."

He stops and places his hands on his hips - the bladed tips of sedge brush at his fingers. He takes in the view.

"The big surprise was the immediate response. A lot of native vegetation has returned."

One year ago, armed with a passion to restore the native habitat, the Sisters Ranger District set their efforts on this lower swamp, southeast from Black Butte Ranch, for restoration (See The Nugget, October 12, 2022). One of nature's finest natural engineers, the beaver, once inhabited the swamp and sustained the water levels by constructing dams. Water would backfill and seep into the surrounding landscape - nourishing a natural habitat once graced by a robust array of wildlife and vegetation.

But after years of trapping and predation, beavers disappeared from the area leaving the fragile ecosystem to it's own devices. So the land dried up. Indian Ford Creek narrowed to a trickle. Willows and birch faded and fell where they stood, dotting the landscape with brittle piles of branches, and desert weeds sprouted in their place. It was a stark contrast to the once-lush landscape of years past.

In September 2022, in partnership with the Central Oregon Youth Conservation Corps (COYCC) and the Heart of Oregon Corps, the Sisters Ranger District collected natural materials - lodgepole pine, branches, and sedge - to build beaver dam analogs (BDAs), or man-made dams. That material was hand-set, woven, and crafted into an imitation of the bygone beaver dam. The hope was the effect would lift the water table and restore the swamp with native habitat. Ultimately, it was an experiment. Only time would tell.

Much to the surprise and delight of those involved, the results were quick. One month after implementing 26 BDAs along a half-mile stretch of the swamp the water table rose six feet. And that rise hasn't abated.

One-inch gray piping with orange caps represent a cross-section of survey wells placed across the area. They allow hydrologists to study the water table and its effect on the wetland hydrology. What they found within those wells were not only significant but consistent and quantifiable rises in the water table.

"Some of the wells went from five to six feet down and now we have water at the surface," Riehle says. "What we found is it takes only weeks for the water table to recharge."

Water brings life, and the return of animals and vegetation is a metric for success. A large amount of natural habitat has returned in 2023 and the presence of wildlife, such as elk, is a common sight again. Birds are also returning; wildlife monitors have spotted mallard ducks and sora rails. Rainbow trout have also been spotted within the creek.

The installations are what Riehle calls "living BDAs." The clumps of sedges and willow branches used to construct them have sprouted and taken root; he hopes the regrowth will help keep them together over time. Throughout the summer COYCC and Heart of Oregon Corps crews adjusted the BDAs and repaired small holes in the dams. Otherwise the builds have remained sturdy. For now the dams appear to be becoming a natural part of the lower swamp.

Last year the vegetation was thin. Looking across the meadow was possible due to thinning foliage and dying trees. It was a dismal, dying landscape. Today, the views abruptly stop at 20 feet in every direction - now obscured by the thick branches of maturing willows and birch trees.

"The willows have gotten really tall," says Riehle, holding a wispy willow branch thick with shoots while also noting that they've grown at least four feet from last year. "They just seem to have more vigor this year because of the water tables. It's amazing."

In stark contrast, a thousand feet northwest of the lower swamp and after a short dusty walk along a horse trail, lies the glum scene of the upper swamp. The familiar sight of dead willow piles and brown clumps of sedge stretch across the meadow and dust kicks up with every step. Dry river channels grow weeds and rotten peat. What remains of Indian Ford Creek here is a feeble ripple, two-feet wide.

Riehle looks at the ground in dismay. "The striking thing is that the only thing that's alive here are weeds," he says. "Vegetatively, this is pretty much a disaster."

Can BDAs solve the problem again? Riehle says he's not sure, but the option is on the table. He says it's important to consider all the options and ensure BDAs wouldn't cause more damage, such as accidentally draining the wetland by creating multiple water channels.

"We're just brainstorming ideas right now," he says. "But we're mostly identifying the problem right now and looking at how water flows through the wetland. This is a unique problem, a little more solid organic soils here."

With more drastic decline comes a more drastic recovery. But that, Riehle says, requires a little more data and a lot more study before implementing an effective plan.

The Lower Black Butte Swamp is providing that data and with the return of wildlife and native habitats it has the Sisters Ranger District motivated and hopeful. BDA's are in consideration for other local restoration projects but this projects success mostly provides an opportunity for hydrologists, scientists, botanists, and wildlife ecologists to learn from.

"I think its turning out to be a big success," says Riehle. "The vegetation is responding, some of the areas that were previously dead are getting re-vegetated with native plants. And I think we've got the project on a good path."

It all comes back to the consideration of that semiaquatic rodent, the beaver.

"We're not completely idealistic thinking that is an essential requirement," he says with a smile. "But to reintroduce the beaver into this wetland, that would be the ultimate goal."