The Nature Conservancy knows Silver Creek needs help.
Decades of heavy grazing have widened the streambed, deposited sediments in the channel and nearly eradicated the willows and other native plants that used to grow on the banks. Fish have fled some areas where the water is shallow and water temperatures are high—a circumstance worrisome in an area known for its fishing.
The conservancy unveiled a preliminary restoration plan last month that calls for narrowing and deepening the stream channels, planting vegetation to shade the stream and lure fish and other wildlife back to damaged areas.
"I think the plan is right on," said Elaine French, a conservancy board member and Picabo landowner.
The removal of silt from the bottom and narrowing the banks is something she knows will help the creek—mostly because she's already executed a similar project on her own land.
Landowners in the Silver Creek drainage south of Bellevue have been carrying out improvement projects independently for at least a decade. Guy Bonnivier, former Silver Creek Preserve manager and current president of environmental contracting firm Conservation Inc., has spearheaded at least a dozen projects along the stream and its tributaries since he retired from the conservancy in 1999.
"When I retired, a lot of landowners wanted me to help them improve their habitat, and a lot of it was in really bad shape," Bonnivier said.
The day after he left the conservancy, he shook hands on a 10-year, seven-mile contract to improve Picabo rancher Tom O'Gara's property. O'Gara had originally wanted to improve the land's property value, but the aim of the project quickly turned to conservation.
The tributaries in need of improvement had been nurseries and spawning grounds for rainbow trout, but the land had been grazed and farmed heavily. Bonnivier said that when he began, there was only one pair of spawning fish in the area.
After one year and one improvement project, that number had increased to 55. Now, the fish from the tributaries on O'Gara's land have moved into the main creek, improving fishing there as well.
Increasing the quality of fish and other water-based wildlife habitat was also the goal of a two-mile project on the Double-R Ranch, a Picabo property owned by lifetime resident Nick Purdy. This was more of a challenge, Bonnivier said. Although the projects on O'Gara's ranch concentrated on tributaries, Purdy's improvements were made to the main stream. Two years of planning were required to form a successful project design.
Grazing at the Double-R had widened the stream to 270 feet, with 3-4 feet of sediment in the bed covered by only 6-8 inches of water. Large trout prefer a depth of about 3 feet, though they will feed in shallow water.
"Velocity was so slow—you could walk faster than the water was moving," Bonnivier said. "It was more like a shallow lake than it was a creek."
Now, the two-mile section of creek is narrower, with roughly 6 feet of water flowing swiftly above a smooth, gravel bed. Excavators were used to unearth rock-hard sediments from the bottom of the stream. The sediments were then used to fill in the widened banks and form the new channel.
Despite the apparent invasiveness of excavation work, which involves moving heavy machinery into the streambed, projects undergo extensive monitoring and regulation in an attempt to mitigate any damage to the stream.
The U.S. Army Corps of Engineers, the Idaho Department of Water Resources, the Idaho Department of Environmental Quality and the Idaho Department of Fish and Game must sign off on a project before Blaine County approves a permit for stream alteration.
Purdy said that in the case of his projects, reviews from these agencies helped take the place of studies such as the one undertaken by The Nature Conservancy with the Boise-based Ecosystem Sciences Foundation.
"We didn't do study after study," Purdy said. "We just went through the proper agencies and got it done."
Both Bonnivier and Purdy are long-term residents, and say they rely on their experiences living on the creek to inform their projects.
"There are very few people who have been in the middle of that river and thinking about restoration for 32 years like I have," Bonnivier said, adding that outside consultants don't have the experience with Silver Creek to come to accurate conclusions.
"It's a very complex system," he said. "Every year, I learn something new. You accumulate knowledge that's impossible for someone to just walk in and know."
Bonnivier's other projects have included work on County Commissioner Larry Schoen's property on Wilson Creek, where he further improved a project started by a consultant from Montana.
"Even in the first year of my project, I saw more fish in there than I've seen in the past 15 years," Schoen said.
Purdy said the fishing on his land has been "tremendous," a statement that Greg Loomis, a fly-fishing guide with Silver Creek Outfitters, said he agrees with.
"I haven't seen a bad rehabilitation project yet," Loomis said.
But the projects' dramatic results are not always visible to the public, due to their location on private land. Because of the seclusion, Bonnivier said, the landowners are often not given enough credit for the impact they've had on the creek.
"Silver Creek improvement is an interconnected plan that has been going on for years," he said.
Silver Creek Preserve Manager Dayna Gross said the goal of the conservancy's plan is to make these projects even more interconnected. Though the enhancement plan calls for work on the preserve, it also contains recommendations for landowners regarding agricultural buffers and riparian plantings as well as future stream rerouting.
Gross said improvements should be planned within the context of the entire watershed.
"People are going to do work no matter what," she said, "and the idea of this plan is to make sure that we are all on the same page, that the silt from my project won't run down and ruin yours."
This plan, however, has met with some criticism from landowners, who say the conservancy should concentrate more on actual improvements.
As former preserve manager, Bonnivier said, he knows the pressure the conservancy is under to make sure Silver Creek stays healthy. Still, he said, the conservancy will have a hard time convincing landowners to follow its plan when parts of the preserve are in "less-than-stellar" condition.
"I would encourage them to focus on some of their own water," he said. "That's a great place to lead by example."
Katherine Wutz: firstname.lastname@example.org