Yellowstone Regional Safeguards Security With New Wildlife Fence

Abundant wildlife is a major attraction at Yellowstone National Park, right up there with its famous geysers. The chance to see everything from bear and bison to raptors and fox draws millions of visitors ever year. While such sightings are welcome within the confines of the park, they are hazards on the airfield of Yellowstone Regional Airport (YRA) in Cody, WY.

Located just minutes from the park’s east entrance, YRA recently replaced its aging perimeter fence to reduce animal incursions. “In the five years leading up to the fence project, we had 11 instances of deer on the airfield. We also had 20 times that deer had to be hazed or led away from the section of the fence that they may have been able to get through,” reports Airport Director Aaron Buck. 

The full-service airport, which averages almost 30,000 operations a year, needed a more secure way to keep wildlife off the airfield. Its 25-year-old perimeter fencing had seen better days. Many wooden posts had rotted away, were broken or had sustained burns during weed control fires.

“It was in very poor shape and varied in height, so its ability to keep or deter wildlife from entering the airfield was limited,” Buck explains.

To mitigate its wildlife risks, YRA constructed a new wildlife fence in 2020. The $818,455 project was paid for with FAA Airport Improvement Program grants.

Focus on Fencing

Airport officials knew they needed a new fence, but an FAA inspection got the ball rolling in 2018. The inspector’s assessment chronicled differing fence heights, weak posts and gaps that posed significant safety risks. The inspector also noted that the size of holes in the fence allowed smaller animals like rabbits, cats, fox and coyotes to squeeze through.

“That inspection pushed the priority of replacing the fence to the forefront,” Buck recalls.

The airport enlisted the services of Morrison-Maierle Inc., a Montana-based engineering firm, and established a $1 million budget for new perimeter fencing.

When collaborating on the fence design, personnel from the airport and engineering firm quickly realized that using chain-link fencing for the entire project would be cost prohibitive. According to estimates, chain-link fencing would cost $32 per foot versus $16 per foot for an option with metal posts and high tensile-strength fencing material with square holes that get progressively smaller toward the bottom of the fence.

“Having smaller openings at the bottom and larger openings higher up reduced fencing costs while keeping animals off the airfield,” explains Austin Reed, a project engineer for Morrison-Maierle. “The fence still provided the protection they needed from smaller animals. And, by making the fence a consistent 8 feet high, they got the protection they needed from deer and other large animals.”

In addition to creating a more formidable barrier for wildlife, Morrison-Maierle designed the fence to withstand weather-related stressors. In the past, high wind and stacked up tumbleweeds had actually tipped over portions of the fence.

“We had to have a beefier fence post to address that concern,” says Reed. “It’s also one reason we picked a high-strength tensile material. It is a lightweight, but resilient, material that could be threaded; so it will not hold the wind or blow in the wind.”

In total, the airport installed more than 18,300 feet of wildlife fencing around the airfield, and 3,000 square feet of chain-link fence around the business areas. Buck notes that nearby Sheridan County Airport installed a similar wildlife fence in 2016, and National County International Airport in Casper, WY, plans to add one soon.

During its fencing project, YRA took the opportunity to tweak entrance gates to make them more accessible/practical. It also removed other gates that were no longer needed.

Good for Business

Mixing wildlife fencing with chain-link fence saved money, but will also support YRA’s business development efforts. The airport had already installed a 3,300-foot chain-link fence around the Choice Aviation entrance, and its more recent fencing project reconfigured access to airport hangars on the airfield.

Previously, tenants needed to go through the perimeter fence to access their hangars. YRA made the entire hangar area accessible to the public by installing new chain-link fencing in line with lots where the airport plans to add hangars and connected it to the back of existing hangars.

“This is a desirable feature that attracts businesses,” Buck says. “Tenants do not always have to access their hangar through perimeter fencing. Before, they needed an airport badge to access their hangar.”

This wasn’t a problem for tenants with badges; but it was an issue for visitors and vendors. “With access in the back, tenants can put a public office there,” explains Buck. 

Construction Delays

Construction began in June 2020, stopped briefly due to material procurement issues, and resumed in August 2020.

Though cases of COVID-19 were rising rapidly at the time, the project never suffered delays because of illness. “The primary delays were material related, primarily with the wildlife fence,” Reed explains. “Chain-link fence was readily available, but the wildlife fence material is more specialized. Plants had shut down that manufacture the high-tensile wire used to produce it. What normally would have been a four-week turnaround turned into roughly five months.”

Fastener backlogs for the project necessitated an exception waiver from the FAA’s Buy American program. “Normally, you can get American-made fasteners without a problem, but they were non-existent during the pandemic,” says Reed.

Installation Issues

Naturally, replacing the fence around an operating airport presents security and logistical challenges. The airport hired Swi Fence and Supply, an installer from Cody, to keep the project moving and meet FAA regulations about maintaining secuity fencing around active airfields.

To do so, Swi often installed sections of the new fence before removing the old one. Crews began by installing fence posts, and then strung the wiring.

“It depended on the area,” Reed says. “In some areas, we could lay the new fence in front of the old fence or vice versa. But in other areas, we had to do things differently.”

For instance, when fencing along a boundary line, crews installed new fencing where the old fence stood. This required them to replace posts before removing old posts. When they were ready to hang the fencing fabric, installers demolished the old fence and immediately rolled out the new fence. “This allowed us to keep our openings to less than 100 feet at a time,” Buck says, noting that the project team also positioned staff to monitor all open areas.

“The contractor had to coordinate the sequence so they could remove old fencing and erect a new fence quickly,” he adds. “They had to cut the old fence into little pieces.”

Inconsistent terrain also challenged the installation crews. The most difficult areas were those with slopes and/or thick vegetation.

Sometimes, vegetation near the fence line limited where installers could work. “Often, we had to work from the airport side of the fence only,” Reed recalls. “Other times, we secured permission to work on private property.”

Installers also had to work around the city’s extensive irrigation network. “We have a very arid climate, and those irrigation canals direct water to area fields,” Buck explains. “They have specific width requirements we had to maintain. Our contractor had to protect those crossings at all times during construction so we didn’t interrupt the flow of irrigation water.”

Positive Results

After more than a year in service, the new fencing is still considered a valuable addition at YRA. Buck reports that it makes the airport more secure and reduces the amount of time staff spends on wildlife management. Previously, if an animal breached the airport, a worker had to chase it off the airfield or sometimes shoot and remove the carcass.

“The new fence has given us more protection, and we have had no animal sightings since the fence went up,” Buck concludes.