Arrow-right Camera
The Spokesman-Review Newspaper
Spokane, Washington  Est. May 19, 1883

Getting There: Abandoned Silver Valley bridge to become a wildlife crossing, fulfilling resident’s longtime dream

 (Molly Quinn/The Spokesman-Review)

Near the small Silver Valley town of Osburn, Idaho, there is an overpass spanning Interstate 90 that no vehicle has crossed since it was built in 1969.

Where most had long seen an abandoned piece of concrete and asphalt, a local hunter saw an opportunity to renegotiate the relationship between people and the animals he revered. Now, a year after that hunter’s death, thanks to locals who took up his torch and governments increasingly willing to mitigate the harms done to animals by highways, that overpass will be converted into a wildlife crossing.

In November, the National Fish and Wildlife Foundation announced $141.3 million in grants to support 74 conservation projects across the country. The smallest of those grants, $250,000, will go to repurposing the Osburn overpass to serve wildlife, funneling large mammals away from the roadway and connecting the Coeur d’Alene and St. Joe national forests.

Leveraging the existing overpass makes the project incredibly inexpensive – compared with the $6.2 million price tag for the wildlife crossing over I-90 near Snoqualmie Pass, which was built from wholecloth and opened in 2018. Money for the Osburn wildlife crossing, which leverages an existing bridge, will mostly be spent building fencing along the highway to funnel wildlife to the crossing, as well as one-way gates that will allow animals stuck on the roadway to jump out.

It has been a longtime coming. Carl Wilson, who passed away a week before Christmas 2022 at the age of 80, had pitched converting the abandoned overpass into a wildlife crossing for more than a decade. He brought the idea to elected officials, engineers, conservationists and last year convened a townhall in the local firehouse with local leaders and government officials to make the plan a reality.

“He came to me in, like, 2008, when it was just a twinkle in his eye,” said Kip McGilvery, who has served as the mayor of Osburn for 12 years.

“It just lit a fire under him,” McGilvery continued. “It’s good to see his dream, that he worked on so hard for all those years, come to fruition.”

Elk are a near daily sighting in the Osburn area, McGilvery said. While many locals admire having the animals around, elk can be a nuisance for maintaining landscapes chewed up by a roving herd.

Elk also pose a safety hazard to motorists when they cross the highway.

“The Silver Valley is a high influx area for tourism,” McGilvery said. “That safety aspect is going to be huge, trying to get them into a defined area and getting them out of roadways.”

Conversely, the elk are also threatened by the busy highway they’re forced to cross. In the past 10 years, the Idaho Transportation Department has recorded 75 large animals, typically elk, deer or moose, that have been found dead after a collision with a vehicle, the second-highest rate of animal mortality on the interstate between Cataldo and the Montana border, said Laura Wolf, regional wildlife biologist for the Idaho state Department of Fish and Wildlife.

“With increasing human population in all of Idaho, you have increased habitat fragmentation and increased traffic taking away habitat, plus the mortality of vehicle wildlife collisions,” Wolf said. “Enabling animals to move as naturally as they want to is very important.”

The impact of the U.S. highway system on wildlife is difficult to overstate due to animals being killed in collisions and species with once-large ranges becoming penned in by dangerous stretches of asphalt into smaller wilderness islands, said Ben Goldfarb, author of “Crossings: How Road Ecology Is Shaping the Future of Our Planet.”

Creating purpose-built wildlife crossings over highways was pioneered by European nations and is increasingly seen by U.S. officials as a meaningful conservation strategy to stitch together the country’s remaining wildlands, Goldfarb noted. The economic and human cost of animal collisions is also significant: A 2022 economic analysis from Washington State University found more than 1,600 wildlife-vehicle collisions occurred each year in Washington. The analysis projected that taxpayers and motorists were saved $235,000 to $443,000 annually for every wildlife crossing because of fewer wrecks.

Different kinds of crossings serve different purposes. Underpasses, which tend to be substantially cheaper to build, are often preferred by some species, such as black bears. The fencing to be built near the Osburn overpass will stretch east to one such underpass, connecting two crossings.

Overpasses tend to be preferred by ungulates like elk, said Kirsten Voorhees, a civil engineer specializing in bridges and animal conveyance whose family has lived in the Osburn area for four generations.

“The big mammals, they don’t like going in tunnels,” Voorhees said. “Based on where their eyes are located, they’d rather be up high looking out at a wide expanse of land.”

Voorhees has helped to garner support for the crossing since 2020, after a cousin told her about Wilson’s work. She was the project’s “enginerd,” she said, while Wilson was the people person.

In spring 2022, Vorhees and Wilson sat down over coffee to discuss their plans and to set goals for the next year. There, Wilson asked Voorhees to make him a promise.

“He told me at the end of that coffee, ‘I need you to get me your word that you’ll see this through if I don’t make it to the finish line,’ ” she said. “I told him, ‘These things take a while, but I have every confidence you’ll be there to see this through.’ ”

Wilson insisted, however, and Voorhees gave him her word. The following December, Wilson died in an accident at his home while fixing his tractor, which he often used during the winter to clear snow for his neighbors.

The project would not have become a reality without Wilson and those he inspired in the community, Wolf said.

“These grants specifically went to community-driven projects,” she noted.

It could still take up to two years before the fencing is installed and the crossing officially opened to hoof traffic, due largely to various environmental reviews required for a project using federal funds, Wolf said.

There are also potential shortfalls to the project. Unlike the crossing in Snoqualmie Pass, which is covered with dirt and vegetation to simulate natural terrain, the Osburn crossing will be covered in the same asphalt it was built with over 50 years ago.

“That’s interesting,” Goldfarb said. “Ideally, you want to make the crossing seem as close to natural as possible for the animals you want to cross.”

But the overpass was built in the 1960s, and a structural analysis would be necessary to determine whether it could hold the additional weight of dirt, Voorhees noted. In order to get the conversion project through the Idaho Transportation Department, it seemed prudent to minimize the amount of work that would need to be done.

“This is a probationary approach,” Voorhees said. “We know for a fact that they’re already walking on asphalt in this area, so we decided to see if they would use the asphalt on this crossing, and if it doesn’t work in a year, then we may think about adding natural materials on top.”

The crossing is also unlikely to be permanent. The bridge was built to a prior era’s clearance standards, and oversized loads currently have to detour off the highway to avoid the low hanging overpass.

“The bridge is not going to be there forever,” Voorhees said. “But I’ll take five years of safety for my community to give us time to fundraise and establish its value so we can fund a replacement that is up to spec for today’s requirements.”