Harmon Den Bridge will feature underpass for animals
âWhen the road was built the wildlife was not taken into account, and now we have these opportunities with replacing these structures to consider them,â said Liz Hillard, a wildlife scientist who is part of the diverse team behind the redesigned bridge. .
The bridge currently under construction at Harmon Den is one of five that the North Carolina Department of Transportation has plans to replace. Georgia-based Kiewit Infrastructure South has landed a $ 19 million contract to replace the first of five, the Exit 7 bridge which has been in use since 1965. The shutdown is expected to begin on Saturday, November 20 and continue through may. when Kiewit plans to implement the new structure. Intermittent track closures will continue until the end of the project in May 2023.
The finished product will not only include an all-new four-lane bridge, but also a specially designed two-lane underpass for wildlife, the first of its kind in the state.
âWe are excited to add wildlife protections to this and other upcoming NCDOT projects,â said Division 14 Engineer Wanda Austin. “We have worked with a wide variety of interest groups, transportation and wildlife experts to incorporate these unique characteristics for the benefit of the people who drive the gorge and the animals that live there.”
First of five
The unique deck plans are largely the result of the efforts of a group that first met in February 2017 in Asheville. Around this time, representatives from various government and nonprofit groups came together to discuss the challenges that busy roads like I-40 pose for wildlife populations. This conversation ultimately spawned Safe Passage: The I-40 Pigeon River Gorge Wildlife Crossing Project, a group of two dozen federal, state, tribal and non-government organizations dedicated to providing safe means for wildlife to cross the I-40 and other roads in the area.
Safe Passage’s first step was to fund research into how wildlife interacts with the road as it is – Hillard of the Wildlands Network and Steve Goodman of the National Parks Conservation Association were chosen to do the work. When they approached NCDOT to obtain the necessary permits to conduct research along the route, Hillard said, the agency began including Safe Passage in discussions of upcoming bridge replacements, seeking advice from Safe Passage on how designs could support safe passageways for wildlife. As a result, engineers, wildlife biologists and other experts have spent the past three years working collaboratively to find the best solution for I-40 bridges.
âIn short, the bridge needs to be replaced and to add these accommodations the cost is rather minimal,â said DOT spokesman David Uchiyama.
An elk uses an underpass for vehicles to cross the highway.
As the cars roll over Cold Springs Creek, animals will be able to safely pass under the bridge via two specially constructed paths – one on either side of the creek – cutting through the riprap provided for the rest of the underside of the bridge. A 9-foot-high fence will guide animals away from traffic and under the bridge, with slotted structures similar to cattle guards discouraging deer and elk from climbing the ramps. While the DOT has built culvert-style animal crossings in the eastern part of the state, this will be the agency’s first experience with this type of design, Uchiyama said, and the first animal crossing of any kind. in the northwest. Caroline.
âIt’s the guinea pig. This is the test, but the plan, at least in theory, should work well, âUchiyama said. “For the bridges that will be built later, we’ll take what we’ve learned from that and apply it to those bridges.”
The Harmon Den Bridge is just one of five bridges slated for replacement in the Pigeon River Gorge. Contracts for two more bridge projects – one crossing White Oak Road and the other spanning both White Oak Road and Jonathan Creek – will be awarded in April, with two more projects on the horizon thereafter. Wildlife crossings won’t necessarily be in the plans for all five, Uchiyama said, but DOT will make those decisions based on the need for wildlife accommodation and the suitability of the site for those specific locations.
Freedom of movement
Hillard hopes the research she and Goodman has done will help make the case for more frequent and comprehensive animal crossing designs. Researchers completed the data collection phase of the project last year, which included laying elk collars, monitoring camera traps, and counting traffic accidents to identify hot spots and problem areas. wildlife. They spent 2021 analyzing the data and aim to release it at the end of the year.
A tally of crash report records, DOT maintenance personnel in Tennessee and North Carolina, weekly driving surveys by researchers and the North Carolina Wildlife Commission showed 162 large mammals have been killed on I-40 in the past four years. Since January 1, 21 deaths have been recorded, including 13 since October 1. Bears account for the largest share of road casualties – over the past four years, at least 92 bears, 69 deer and one moose have died on the Highway. The numbers probably represent an undercoverage.
âMaking sure the wildlife is free to roam is important, so this Harmon Den opportunity is a great one,â Hillard said. âIt is this unique opportunity to increase and provide connectivity to wildlife habitats. “
Almost all of Safe Passage’s 28-mile project area through the gorge crosses undeveloped public land which is critical habitat for the region’s wildlife. In Haywood County, the road passes through the Pisgah National Forest, which becomes the Cherokee National Forest when the road passes through Tennessee. The boundary of the Great Smoky Mountains National Park is a short distance west of the highway.
These vast expanses of land provide vital habitat for a variety of species ranging from bears to salamanders, but when these animals have to move from one side of the gorge to the other, whether for food, mate or seasonally migrate , they face a danger of death.
âHaving a place where wildlife can cross under the freeway safely is a big deal just based on the availability of resources and things like that,â Hillard said. “Especially when you think of the southern Appalachians, with climate change warming, wildlife is going to move north.”
As the effort progresses, Hillard and his colleagues at Safe Passage hope to see wildlife-focused infrastructure become the norm rather than the exception, with the dream of building a large dedicated wildlife viaduct across the river. throat. Hillard also wants the conversation to extend beyond mammals to consider passages for aquatic species as well. Many culverts and other structures in place now do not allow fish and other aquatic organisms to move easily from side to side.
While the DOT has been able to absorb the cost of hosting the wildlife crossings within its existing budget for the Harmon Den project, this will not always be the case. Additional sources of funding may be needed for future projects. To that end, Safe Passage is raising donations to support its efforts – but an even bigger boost could come from the federal infrastructure bill President Joe Biden signed on November 15. The $ 1.2 trillion bill includes $ 350 million in grants for a wildlife crossing pilot program.
âWe look forward to working with all groups, whether non-governmental or advocacy,â Uchiyama said. âFrom what we’ve seen so far, the collaboration has been phenomenal.
Learn more about the Safe Passage project or donate at smokiessafepassage.org.
Delays ahead at I-40
Starting Saturday, November 20, I-40 will shrink to one lane in each direction as it approaches Exit 7 for Harmon Den, with all traffic being forced to exit and bypass the bridge using the ramps. highway access and exit.
The detour will allow contractor Kiewit Infrastructure to remove the deteriorating bridge and replace it with a new structure and is expected to remain in effect until May of next year. After the road reopens, slowdowns and lane closures are expected until the project’s final completion date in May 2023.
To bypass road works, travelers from Asheville can take I-26 West to Kingsport, then I-81 South to Dandridge. The NCDOT urges drivers to ignore travel app instructions directing them to bypass road works by using any exit between Asheville and Newport, Tennessee. Many of these roads are unpaved and feature steep slopes and sharp curves. Trucks are prohibited from transporting US 25/70 through Madison and Cocke counties.