The Idaho Transportation Department wants to know—how long should it take to complete a repair of an active but slow-moving landslide below state Highway 75 just south of Galena Summit?
The project will unfurl in six-month increments over two to three years, for a total of 12 to 18 months. If ITD opts for the two-year option, it will require some road closures at night.
Spacing it out to three years will still have an impact on traffic. Crews would use traffic signals, flagging, pilot cars and closures during periods of blasting rock on the north side of Galena Summit and transporting it to the slide area. Bicycle traffic could be closed in the construction zones.
The rock will be trucked down to the base of the slide area, where it will be used to build a toe berm to buttress against the slide and keep it from moving. The nighttime closures would be from Sunday through Friday from 7 p.m. to 7 a.m., but would exclude emergency traffic.
The construction work would take place in the summer and fall seasons.
ITD does not have a scheduled start date for the project, because it is still undergoing environmental review with the Federal Highway Administration.
The department is taking public feedback on the options through the end of November. Comments will be submitted to the federal government along with the project’s environmental documents.
ITD hopes to have those submitted by the end of the year or in January. The Federal Highway Administration will ultimately decide on the two options, ITD spokeswoman Jesse Williams said at a community meeting in Hailey last week.
“Right now, we’re really just seeking comment on the time frame of it,” Williams said.
ITD decided last year to go ahead with the project. The department will hire a contracting company to blast rock that abuts Highway 75 on the north side of Galena Summit. That will be moved over the summit and down to the landslide area, where it will help construct the toe berm.
The project requires moving 100,000 cubic yards of dirt and rock over the summit, ITD engineer Walter Burnside said at the meeting.
That is intended to be a permanent fix for the slide, which migrates slightly each year following snow and rain and other natural influences. It moved 12 inches following the heavy snows in the winter of 2017, according to ITD.
Waiting to do the repair project—or not doing it at all—means that ITD will continue to do maintenance or have to realign the highway.
Burnside said it will take at least a year to determine if the buttress is sufficient to stop the slide. If not, further work and buttressing will be needed.
“It will take one to three years for that slide to migrate up against that buttress,” Burnside said. “It’s not like we can drop it in, and boom it stops moving. We intend for it to be stabilized.”
Inevitably, the work will disrupt traffic for visitors, residents, bicyclists and recreationists on Highway 75 from the Wood River Valley to the Sawtooth Valley and the Stanley Basin.
Jason Bosley, executive director of the Stanley-Sawtooth Chamber of Commerce, said he understands the need for the project, and hopes ITD will be able to include as much mitigation as possible for traffic disruptions.
He said combating a public perception may be more challenging that waiting through traffic to get over Galena Summit once construction begins. He said the chamber is concerned that people will think the Sawtooth Valley and the Stanley Basin are closed off, and tourists and visitors won’t make the effort to go.
Many day trips from the Wood River Valley to the Sawtooth Valley don’t occur with great forethought or significant planning, Bosley said. He said the chamber represents about 75 businesses in the Stanley region.
“People say, ‘Oh, you should take a trip up to Stanley,’ and they do it on a whim without a lot of planning,” he said. “I feel like that person would be really easily dissuaded.”
He said that once the planning for the project advances, he hopes ITD will provide a more detailed breakdown of potential disruptions. That would include estimates of how long traffic could be delayed and when, so travelers could adjust accordingly.
Bosley said he is considering reaching out to the Idaho Travel Council or other statewide tourism organizations for help in communicating to the public once the project nears its start date.
He said he hopes to avoid a situation that happened on the Idaho-Utah border, in which ITD recommended that Idaho-bound drivers from Salt Lake City take a detour into Wyoming because of a construction project on the Idaho side of the border.
“ITD is not really in the business of tourism,” he said. “[But] they’re making some plans to mitigate an impact. I don’t think construction’s going to be that bad. I think it’s going to be a perception.”
ITD Environmental Planner Connie Jones said the buttress will cover some historic trails that once took travelers north over Galena Summit. That includes a portion of the path of an old toll road over the summit.
Jones said ITD has worked with the U.S. Forest Service and the Blaine County Historical Society to gather information about the history of the road. It plans to install a sign on the highway denoting the history of the toll road, similar to a sign that features historical information about explorer Alexander Ross. The new sign could be set up in the same location as the Ross sign, on an overlook with views of the Boulder Mountains, Jones said.