Following Blaine County’s approval of the necessary permits this week, The Nature Conservancy and Picabo Livestock Co. intend to begin restoration work at Kilpatrick Pond on Silver Creek early this fall and to be done with most of it by winter.
At the conclusion of a well-attended public hearing Tuesday, county commissioners unanimously approved stream-alteration permits to replace the dam at the pond, dredge sediment that has accumulated there and reduce the pond’s size by rechannelizing the stream and creating adjacent wetlands. Permits from the state were approved by the Idaho Department of Water Resources in late May.
The project’s intent is to re-create original cold-water habitat conditions in the spring-fed creek.
In an interview, Silver Creek Manager Dayna Gross said contractors for the project will be chosen in mid-July and dredging will begin in September while irrigation season still provides enough water for the dredge to float. Once the water level drops, work will begin on replacing the dam, installing bank structures and building an island with the dredged material to create wetlands.
“The hope is to have pretty much everything done by the end of the year,” she said.
Gross said planting and erosion-control work will be done in the spring.
“It will probably look pretty bad next spring, but it will improve quickly,” she said.
Gross said estimated cost of the entire project is about $1 million, funded by private donations and by a grant from the Natural Resources Conservation Service for the materials that will be used for wetlands creation. She said the amount of the grant will depend on the as-yet-undetermined cost of the materials.
Since it was proposed in August 2012, the project has been controversial among fly fishermen. The county received 110 written comments on the application, 74 in support of the project and 36 opposed, as well as a petition in opposition with 63 signatures. Concerns included the potential for reduced access to the creek, difficulty in walking or wading back upstream due to faster water and more vegetation, and unintended consequences on fish and insect habitat of such a large-scale restoration project.
“The public has access to some of the finest fishing in North America in this water, and that really explains the nature of the public response to these applications,” Commissioner Larry Schoen said during Tuesday’s meeting in Hailey.
Schoen said there had been a “remarkable” depth of scientific knowledge shown in the comments.
Engineer and hydrologist Chuck Brockway, who had been hired by Picabo Livestock Co., addressed public concerns of uncertainty about the project’s effects on water temperature.
“I don’t think it’s correct to say that the science isn’t settled,” Brockway said. “The science is more than settled on what affects thermal loading. We’re having a beneficial effect on all of these.”
He acknowledged that the amount of temperature reduction in various parts of the creek is difficult to predict, but said temperatures will continue to be monitored after the project’s completion.
Brockway said water will flow from the new dam both below and above it, allowing for adjustment of temperature in the creek downstream.
Addressing access concerns, Gross said the project will create no added restrictions to access on the Silver Creek Preserve side of the creek, though additional vegetation growth might require fisherman walking along the bank to wade in the stream in some places. Picabo Livestock Co. owner Nick Purdy said now-vertical banks on his side of the creek will be more sloped, allowing for easier walking.
“I don’t see any detriment at all to access,” he said. “It should be as good or better.”
At the conclusion of the meeting, the commissioners said the applications met the standards imposed by county ordinance for approval of the permits.
“I really believe in the physics of this project and the design characteristics that are intended to address sediment transport and thermal loading,” Schoen said. “This project will afford good fishing access bank to bank and similar opportunities for ingress and egress.”