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NCDOT builds road bridges for wildlife and humans | North Carolina News

By RICHARD STRADLING, The News & Observer

Raleigh, NC (AP) – The North Carolina Department of Transportation is building a bridge over Interstate 40 that is one of the first in the state to accommodate the needs of bears and elk.

The bridge will carry I-40 over Cold Springs Creek and Harmon Den Road, near the Tennessee border, into the narrow, winding gorges of the Pigeon River.

The highway creates a barrier there between two sections of the Pisgah National Forest. To the south and west is the Great Smoky Mountains National Park and its growing elk population centered in the Cataloochee Valley. To the north and east is Max Patch, a 4,600-foot bald mountain that is popular with hikers and wildlife, including elk.

This month, a contractor began work on a new bridge at Harmon Den Road that will include more room for animals to follow the creek under the freeway. New 9ft high fences on each side will direct bears, deer, elk and other wildlife to the bridge opening. Meanwhile, cattle guards – steel beam grates that farmers and ranchers use to keep livestock from wandering – will be built into the sidewalk on the exit and entry ramps.

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“I don’t know if we’ve done this in North Carolina before in this type of situation, putting a cattle ranger on an interstate freeway to keep animals from getting on the freeway,” Wanda Austin said, NCDOT division engineer for the region. .

The hope is that by making it easier for animals to pass under the freeway, they won’t cross the sidewalk and put themselves and people in danger, says Liz Hillard, a wildlife scientist in the group. Conservation Wildlands Network which studies the movements of animals in the throat. .

“They need these large areas to move around and find resources,” Hillard said. “And then there is the human security aspect. Hitting a 1,000 pound swing is dangerous.

Wildlife crossings are more common in the west, Hillard said. In Montana, for example, the state Department of Transportation has constructed more than 40 wildlife crossings along a US 93 stretch through the Flathead Indian Reservation, including a large overpass covered with grass for bears, deer, elk and moose.


NCDOT has also made arrangements for wildlife, although much less often. In the 1990s, at the request of the NC Wildlife Resources Commission, it constructed two culverts under a new section of Interstate 26 northwest of Asheville for black bears. NCDOT then worked with the commission to design and construct three underground passages for bears, deer, red wolves and other animals under a new stretch of US 64 in Washington County, east of Plymouth.

In 2005, NCDOT agreed to build a taller and longer replacement bridge for US 15-501 over New Hope Creek in Durham to make room for wildlife, primarily deer following the stream. Ron Sutherland, chief scientist at Wildlands Network, said the group had studied how deer used the passage and, with cameras mounted on the bridge, had counted more than 2,000 in a single year.

“I think our data shows the 15-501 bridge was a huge success,” Sutherland said. “Thousands of people cross this bridge every day without knowing how many deer and other wildlife are safely moving underneath.”

NCDOT is planning a more ambitious crossing in Graham County, where the Appalachian Trail crosses NC 143 at Stecoah Gap. The Corridor K project, as it is known, calls on the state to build a land bridge, planted with vegetation, to transport hikers and wildlife on the road.

“It’s really just protecting this corridor for wildlife and making it safer from a hiker’s point of view, so they don’t get out on the road,” Austin said. “And obviously that helps the automotive public as well.”


When I-40 was built through Pigeon River Gorge in the late 1960s, little thought was given to wildlife, in part because there weren’t so many. Elk had not been seen in North Carolina since the late 1700s, and black bears were relatively rare.

Things have changed. Elk were reintroduced to Cataloochee in 2001, and bears have become so numerous that sightings on the streets of western North Carolina’s largest city, Asheville, have become routine.

Initially, conservationists wondered how it would be easier for elk to safely cross I-40 in the Pigeon River Gorge, says Jeff Hunter, regional director of the National Parks Conservation Association. This led to a reunion in the winter of 2017 that turned into a conversation about other types of wildlife.

Hunter says he approached NCDOT about hosting wildlife in the gorge later that year and got few responses.

That started to change the following year, he says, when the Federal Highway Administration hosted a two-day wildlife crossing strategies workshop in Maggie Valley, not far from the gorge. NCDOT has since engaged with conservation groups in the mountains, says Hunter, and was receptive to the Harmon Den Road Bridge modification.

“This is a very positive step forward, and it is an indication that the agency itself is changing,” said Hunter. “Hearts and minds and therefore culture, which is exciting to see. “

The NCDOT replaces the Harmon Den Road Bridge, and possibly four more on I-40 in the Gorge, due to age and deterioration. The bridge was demolished this month, and two-way traffic is stuck in one lane and diverted to the exit and entry ramps, causing delays.

The new bridge, which is scheduled to open to traffic at the end of next spring, will be the same length as the old one. But the abutments of the bridge have been redesigned to provide more space below. The extra space will be used for flat trails on both sides of Cold Springs Creek which Hillard says should serve as “green trails for wildlife.”


Conservation groups have formed a coalition called Safe Passage that hopes to find other ways to help wildlife safely cross I-40 and other roads in western North Carolina and the east of Tennessee. He has spent over two years studying how and where animals cross the highway, using GPS elk collars, weekly animal carcass surveys along the highway, and over 100 remote cameras.

Harmon Den Road is one of many hot spots along the 28-mile stretch of road crossing the gorge, in part because the river and creek provide natural routes for wildlife to follow.

Fences, livestock guards and wildlife trails will add little to the $ 19 million cost of replacing the bridge, said Austin, the NCDOT engineer. Hunter said Safe Passage has raised more than $ 100,000 to help cover additional costs and will raise more if needed.

Safe Passage will use the data collected to point out other locations where NCDOT could help wildlife cross the highway.

Potential strategies include new terrestrial bridges or tunnels, but also new fences to direct animals to existing culverts or modernization or expansion of culverts to facilitate animal passage. President Joe Biden’s infrastructure bill includes $ 350 million for nationwide animal passage projects.

“In the I-40 hallway, Harmon Den is a really, really positive start,” Hunter said. “But there is more to do.”

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