Interstate 40

By Holly Kays | Lead Writer, Smokies Life

Editor’s note: This piece is the second of a two-part series exploring plans to rebuild I-40 through the Pigeon River Gorge and the project’s implication for wildlife populations in the region. Find the first installment here.

As the floodwaters of Hurricane Helene receded, they revealed extensive damage to Interstate 40 through the Pigeon River Gorge, promising that the rebuilding effort would be a top priority for the NC Department of Transportation in the years ahead. The agency has spent the past year exploring potential solutions, and now the plans are reaching their final form. The $2 billion project calls for a massive concrete wall— intended to stabilize the slope and protect it from erosion—that will run alongside the road for most of the 4.5-mile rebuild area.

Engineers see the plan as an innovative approach that will create a safe and stable roadway capable of standing strong against future storms. But members of the Safe Passage coalition, a group of organizations and individuals working since 2017 to reduce wildlife–vehicle collisions on the road, fear it will represent a generational loss for wildlife connectivity in the gorge—unless the plans are amended before implementation.

“It took ten years to get here, and it is a setback,” said Wanda Payne, Safe Passage’s liaison with NCDOT and a former Division 14 engineer with the agency. “But I think while you’re in that transition of ‘storming to get to norming’ in your process of development, there’s going to be losses and there’s going to be gains. And this is a hard loss, if [the final outcome] is going to be a loss.”

After the hurricane passed, Safe Passage had hoped for a silver lining to emerge from the storm clouds: improved opportunities for wildlife connectivity on the rebuilt road. But though NCDOT considered various ideas recommended by the group, ultimately federal reimbursement rules dictated the terms. Emergency funds from the Federal Highway Administration are available only for road “replacements,” not road “improvements”—and, according to FHWA, most things on Safe Passage’s wish list would fall under the latter category.

NCDOT engineers worked with FHWA representatives “every step of the way” to understand how various approaches might fare, said John Jamison, head of NCDOT’s Environmental Policy Unit. But even within that guidance, NCDOT has an incentive to act cautiously. The project isn’t slated for completion until late 2028 at the earliest, and federal reimbursements can take years or even decades to come through. Final approval for the funds could easily fall into the hands of someone who had no part in today’s conversations.

“You don’t want to risk Federal Highways saying, on a billion-dollar project, ‘Well you didn’t dot that ‘i,’ so you’re just out,’” said Payne. “And that’s what they could do, theoretically. So it’s a big gamble.”

These considerations led the design team to conclude that a massive retaining wall would be “the only viable option” for I-40, said Division 14 Construction Engineer Joshua Deyton. The extremely steep slope required a wall system, but the type of wall NCDOT had selected when repairing damage from Hurricanes Frances and Ivan in 2004 failed during Helene.

“That meant we had to put something back that was more resilient,” said Brian Burch, deputy program manager for design firm HNTB Corporation and former Division 14 engineer. “Two elements we decided would withstand Hurricane Helene and would allow us to build this wall-type system was interlocking pipe piles and roller-compacted concrete.”

Roller-compacted concrete, an extremely durable material used for everything from dams to container yard pavement, will form a wall along most of the 4.5-mile stretch, standing 20–30 feet tall and averaging 30 feet thick. An underground barrier of interlocking pipes buried 36 feet deep will prevent water from undermining the concrete edifice.

“Once they got the designs together, we saw there were going to be some major wall-like structures out there, extensive riprap in the gorge section, and we said, ‘What can we do to offset this?’” said David McHenry, NCDOT liaison for the NC Wildlife Resources Commission.

An agreement between NCDOT and the US Forest Service helped answer that question. NCDOT is taking road fill material for the project from nearby USFS land, and as a result NCDOT has agreed to several actions offsetting the resulting negative environmental impacts. The agreement includes four wildlife crossing projects on I-40, two of which—the double tunnel and Groundhog Creek—fall within the rebuild area.

Under the agreement, NCDOT pledges to install wildlife fencing at Wilkins Creek and build a ramp at the double tunnel allowing wildlife to again access the river where Helene had created an impassable cliff. The agreement also includes constructing  wildlife passage facilities at Groundhog Creek and Cold Springs Creek “where practical and functional at locations proposed” in an unfunded 2024 grant proposal. Both sites contain multiple culverts, and the proposal called for adding benching or other material to create a dry crossing in one of them suitable for animals unable to navigate wet pipes, such as skunks, shrews, and snakes.

However, a 2022 research report funded by Safe Passage and created by Wildlands Network and National Parks Conservation Association wildlife biologists had recommended a different solution for Groundhog Creek: replacing the three smaller culverts installed there with one big culvert that even large animals like antlered deer could use. The report also recommended adding a dry crossing and creating a natural creek bottom in the culvert suitable for aquatic creatures.

“That has yet to be determined whether they will be replaced,” said Marissa Cox, western regional team lead for NCDOT’s Environmental Policy Unit. “My understanding is they are currently under investigation right now and no final decisions have been made as to any replacement or repairs or extensions of those pipes.”

The road design team, together with NCDOT and NCWRC officials, recently visited the gorge to review potential sites—which include “any tributary where dry passage may be possible”—with a follow-up meeting scheduled soon, Cox said.

Replacing the culverts would be extremely expensive, said Division 14 Engineer Wesley Grindstaff. They’re too deep to be replaced through a cut to the road’s surface, and the boulders used to fill the slope in the 1960s would complicate a horizontal approach. Because the culverts remained intact during Helene, federal funds would not cover their replacement.

The NCDOT–USFS agreement also includes several projects outside the I-40 corridor: a new bridge at Buzzard Roost Road to replace an existing concrete structure, which creates a barrier for aquatic species and is impassable to vehicles during high water; 8.86 miles of stream improvements to offset 1.3 miles of streams that will be “lost or permanently altered” due to quarry operations; and acquiring more than 1,000 acres of land, to be conveyed to USFS.

“We’re going to do what we can to do improvements where we can, and I think we’ve got a pretty good plan,” McHenry said.

If all goes as anticipated, the wall will remain part of the landscape for generations to come.

“The expectation is that whatever repairs we do this time, it will be permanent,” said Burch. “We don’t expect any other failures at that point.”

Without culvert replacements, Ron Sutherland, chief scientist for Wildlands Network and Safe Passage coalition member, is skeptical. During Helene, the gorge saw significantly less rainfall than other parts of the region, so the culverts running under I-40 weren’t put to the test like those in other areas.

“If we get a good strike from a hurricane that hits the Pigeon River Gorge local watershed, as steep as it is, it’s going to overwhelm those culverts,” Sutherland said.

NCDOT did design the new road with strengthening storms in mind, Grindstaff said. The agency typically builds new infrastructure to withstand a 100-year flood event, but Helene—in the gorge, considered a 500-year event—was used as the baseline comparison for the rebuild.

However, in much of the region, Helene brought on a 1,000-year flood or worse—though that term is a misleading moniker. It describes probability, not frequency. A 500-year flood, for example, is an event that, based on historical data (not forecasted future trends), has a 1 in 500 chance of occurring in any given year—0.2 percent annually. Likewise, every year there is a 0.1 percent chance of a “1,000-year flood” occurring. Helene’s arrival in 2024 has no bearing on the probability that a similar flood might occur in any subsequent year.

Especially in a warming climate, unlucky dice rolls are increasingly common. Parts of Western North Carolina saw a 100-year flood in 2004 after Hurricane Ivan came close on the heels of Hurricane Frances, and again in 2021 from Tropical Storm Fred. Then Helene landed in 2024.

“These weather events, as far as the intensity, seem to be greater over the last many years,” Burch said. “The intensities of the storms are greater, and they’re more frequent. So working with our federal partners the decision was made: Let’s try to build something back that’s going to withstand the next Helene.”

Regardless of whether the DOT meets that goal, the finished road will be a complex structure that won’t offer much opportunity for wildlife-oriented retrofitting once complete—though opportunities remain in other parts of the gorge. The 2022 report listed multiple priority projects outside the 4.5-mile stretch slated for reconstruction, and NCDOT “depends on and appreciates and utilizes” those recommendations, Grindstaff said.

The issue of wildlife crossings has come a long way since Safe Passage began. Despite Canada and Europe having made wildlife mitigation part of road building for the past half-century, as recently as a decade ago the issue barely received a passing consideration from road planners in the Southern Appalachians. But now—despite the unique constraints influencing the I-40 rebuild—road ecology is becoming a standard topic of discussion.

And, increasingly, funds are available to address it. In 2023 the NC General Assembly appropriated $2 million for wildlife fencing and related projects in the Pigeon River Gorge, and the body is considering an additional $10 million in its next two-year budget. In 2021, Congress authorized $350 million for the Wildlife Crossings Pilot Program—to be distributed as grants in fiscal years 2022–2026—and a bipartisan bill has been introduced seeking to extend the program. At both the state and federal level, the issue is gaining momentum. Payne likens the change to the rise of bicycle lanes and pedestrian features. Once seen as optional add-ons, they’re now integral parts of road planning.

But the planned wall would be a loss for wildlife that can’t be replaced by improvements elsewhere, Safe Passage advocates say, maintaining optimism that additional mitigations can be incorporated before it’s too late.

“We’ve got a window of opportunity,” said Jeff Hunter, NPCA’s Southern Appalachian director, “and I would hate to see that window close.”

By Holly Kays | Lead Writer, Smokies Life

Editor’s note: This piece is the first of a two-part series exploring plans to rebuild I-40 through the Pigeon River Gorge and the project’s implication for wildlife populations in the region.

When I-40 through the Pigeon River Gorge first opened in October 1968, it was hailed as a triumph of human accomplishment, the dawn of a new era for travel, tourism, and economic opportunity in newly linked Haywood County, North Carolina, and Cocke County, Tennessee. “Instead of going over or around mountains . . . man now goes through them,” proclaimed an advertisement in the special issue of the Waynesville Mountaineer celebrating the road’s grand opening. 

But this “milestone to the genius of man” was more vulnerable than it first appeared, as proven by Hurricane Helene’s September 2024 onslaught. The raging Pigeon River undercut the steep slopes supporting the road, carrying away entire chunks of eastbound lanes in the worst-hit section, extending from the Tennessee–North Carolina line to NC mile marker 4.5. The road remained closed through March 1, 2025, reopening with 12 miles of single-lane travel in each direction.

Natural forces have caused plenty of closures during the road’s nearly 60 years of existence—rockslides from the sheer cliffs rising from the north side are the most common reason—but Helene was unique in the scale of the damage it caused. Rebuilding a road that would provide safety to travelers and durability in the face of future natural disasters presented the NC Department of Transportation with a monumental task.

It also stands out as a once-in-a-lifetime opportunity to the Safe Passage coalition, a group that has been working since 2017 to reduce wildlife–vehicle collisions in the gorge. The project has the potential to be an enormous win for wildlife connectivity in the gorge—or a huge loss. The cost is currently estimated at $2 billion, and engineers hope the rebuilt road will last for as long as 100 years after its completion in late 2028 or early 2029, meaning it could remain in place for generations.

In the first project of its kind in North Carolina, NCDOT plans to use roller-compacted concrete to build an enormous wall—20–30 feet tall and averaging 30 feet thick—stabilizing the slope between the road and the river and protecting it from erosion. Those plans, nearing their final form, have Safe Passage members alarmed.

“It would be a huge loss for the Safe Passage coalition and everything we’ve been trying to accomplish,” said Ron Sutherland, chief scientist for Wildlands Network, a Safe Passage coalition member.

The Pigeon River Gorge has been the focus of Safe Passage’s work since its inception, with the I-40 corridor representing a unique risk to wildlife connectivity and biodiversity. The road section, which in 2023, prior to Helene, saw an average of 26,500 cars each day, divides a rugged mountain landscape that includes a narrow band of national forest acreage, about half of which falls within the rebuild area. This forest connects a swath of federal land stretching hundreds of miles from northern Georgia into northern Virginia and southern West Virginia. Great Smoky Mountains National Park, the most biodiverse site in the National Park System, lies just to the south. Ensuring animals can move safely from one side of the highway to the other is crucial to ensuring genetic health and resilience in the face of hardships like food shortages, habitat loss, or changes in climate.

“It would be difficult to overstate the importance of this corridor from the Great Smoky Mountains northeastward for wildlife and biodiversity,” Sutherland said. “It’s kind of the major pathway for wildlife and climate migration and everything else in the whole region.”

NCDOT has been a partner in that priority, collaborating with Safe Passage and, where possible, integrating the group’s recommendations into its designs. Many of these recommendations came from a 2022 report that was based on a three-year study focused on bear, deer, and elk movements. Funded by Safe Passage, the study was conducted by wildlife biologists with Wildlands Network and National Parks Conservation Association to identify the gorge’s wildlife crossing hotspots and make recommendations to help support habitat connectivity and improve transportation safety.

While the study was still underway, Safe Passage used the emerging data to deliver recommendations for five bridges slated for replacement in the gorge. As a result, the Harmon Den bridge at Exit 7, completed in 2023, features wildlife-friendly dirt paths underneath as well as fencing and cattle guards to prevent animals from wandering onto the highway. Four additional bridge projects in the area are now either complete or nearly so. All include some type of research-driven wildlife crossing feature, and all survived Helene. Meanwhile, NCDOT’s growing relationship with Safe Passage helped inspire the design of a new overpass for wildlife and Appalachian Trail hikers, currently being installed on NC 143 at Stecoah Gap near Robbinsville, North Carolina.

“These are all really positive things,” said Jeff Hunter, NPCA’s Southern Appalachian director. “Unfortunately, Helene set us back.”

Before the hurricane, the decimated section of I-40 contained one of the most important wildlife crossings in the entire gorge: the double tunnel, where all four lanes of the highway go underground, leaving a natural, wooded area on top that creates an earthen bridge for wildlife. But Helene carried away the land that had connected this bridge to the river, leaving animals to navigate an impassable 90-degree drop-off.

“None of us, I don’t think, could have envisioned we would have lost that crossing,” Hunter said.

Pre-Helene, the big push in this area had been at nearby Groundhog Creek, where Safe Passage hoped to carry out a culvert improvement project that would greatly benefit wildlife connectivity. Culverts don’t just move water; wildlife use them too. The 2022 report had found that the trio of culverts moving Groundhog Creek under I-40 had some of the highest levels of wildlife activity in the entire gorge, with cameras recording species ranging from bobcat to bear. To make the crossing even more effective, researchers recommended replacing the three culverts with one big pipe able to accommodate even large animals like antlered deer and elk, with additional modifications to make it more useful to a wide range of species. The report also recommended enlarging the culvert at Snowbird Creek, also located within the rebuild corridor; though topography prevented researchers from placing a camera there, collision data indicated the creek crossing was a hotspot for wildlife activity.

But Helene changed the equation, creating an urgent situation that required immediate action on I-40—and, simultaneously, everywhere else in Western North Carolina. With reliable thoroughfares obliterated and entire communities cut off from the outside world, NCDOT faced a seemingly impossible task.

“When it comes to emergency repair projects like this, it’s of course an all-hands-on-deck kind of approach,” said John Jamison, head of NCDOT’s Environmental Policy Unit. “Not only is it a rush to figure out what needs to be repaired and how to repair it and actually do the repairs, but there’s a lot that goes into the conversation about how does it get funded.”

Normally, major road projects go through a years-long process of planning, design, and community engagement. Before the first shovel hits the ground, NCDOT and local stakeholders engage in extensive conversations about the proposed plan, alternative approaches, and opportunities to fund enhancements.

But Helene recovery projects are a form of emergency response and don’t follow that same process. Nor are they primarily tied to state funding. Instead, the Federal Highway Administration’s Emergency Relief Program covers up to 90 percent of the cost—provided plans meet the agency’s criteria. For NCDOT, that financial support was critical. Hurricane recovery projects across the state are expected to total about $5.8 billion, an enormous expenditure considering that in fiscal year 2023–2024, funding for construction projects statewide came in at $3.5 billion.

“We’re essentially funding a big loan on these projects,” Jamison said.

As the floodwaters receded, Safe Passage members had high hopes that the tragedy could hold a silver lining for wildlife. With I-40 closed and major roadwork inevitable, why not add culvert enlargements or even road section reroutes into the recovery plan? Could the highway perhaps be reimagined as a viaduct, supported by pylons that would allow both water and wildlife to move freely underneath?

But federal reimbursement rules—combined with a desire to see the road fully reopen as quickly as possible—have dashed those hopes. FHWA emergency funds cover only road “replacements,” not road “improvements.” Though the eastbound lanes were severely damaged, westbound lanes and culverts remained intact, so the kinds of projects on Safe Passage’s wish list would have fallen under the “improvements” category, leaving NC taxpayers on the hook for the entire cost.

“That funding uncertainty made it fairly straightforward for us to stick to the existing roadway,” Jamison said.

Part 2 of this series will take a closer look at the planned rebuild, opportunities to benefit wildlife passage, and the factors influencing these decisions.