Helicopters have been spotted across Western North Carolina over the last two weeks, which Duke Energy confirmed to be part of the aerial herbicide application process on Monday.
“We are conducting our aerial herbicide program across Swain, Macon and Jackson counties around our transmission line rights-of-way that are difficult to access for ground crews over the next 4-6 weeks, weather permitting, said Meghan Miles with Duke Energy.
Duke Energy has included aerial herbicide applications in their vegetation management strategies since 2016, during which time some towns and counties have vocally opposed the method. Residents have taken to social media over the last week to voice their concern in the usage of chemicals, as well as potentially adverse impacts down the road.
In order to provide uninterrupted electrical services, lines that transmit electricity must remain free from trees and other vegetation. While trees are part of the natural beauty of the region, they are also a leading cause of power outages and power quality issues. Vegetation near power lines can also present a potential safety threat for utility crews and the public. Managing vegetation along power lines and in rights of way is an effective way to improve reliability for our customers, according to Duke.
Aerial herbicide applications are one of many vegetation management methods that Duke Energy employs, including tree cutting and removal, mowing and manual backpack spraying.
With questions and concerns coming from the public annually when helicopters are deployed, Duke is working to become more proactive in informing communities when the practice will be used and why they do it.
Aerial applications typically occur in areas of high brush density, where rough terrain makes the use of powered equipment or manual application by ground crews difficult or unsafe.
Portions of Duke Energy’s transmission line rights-of-way are difficult to access for ground crews paired with high brush density in Swain, Macon and Jackson counties. Therefore, aerial herbicide applications are being made on these sections of the transmission line rights-of-way.
Aerial herbicide applications are conducted within strict regulatory guidelines and practices designed to protect residential areas, farming activities, public waters, wetlands, endangered species habitats, and cultural resources.
During the process, Duke Energy works to avoid neighborhoods, schools and community gathering spaces, as well as field workers and domesticated animals.
“We review each site to evaluate potential obstacles and hazards before any herbicide applications are conducted,” said Duke. “We adhere to all federal and state buffer regulations, and our goal is to stay 100 feet or more away from residences from the edge of our right of way.”
Applying herbicides from the air is a safer and more effective alternative to sending crews on foot to perform backpack herbicide spraying in rough and mountainous terrain or hard-to-access areas,” said Miles. “Aerial maintenance applications can be completed much more quickly than manual spraying, reducing crew exposure to physical hazards in the right-of-way environment.”
To ensure safe application, weather conditions are constantly monitored and the work does not occur if wind gusts exceed 10 mph. GIS data is also used to allow workers to more accurately place droplets of the product – not a mist – at each site to better target vegetation in our right-of-way that could create reliability issues. This targeted approach is also expected to reduce the frequency of herbicide applications in the future.
Product mixes are diluted at the point of application and are predominantly water – approximately 90 percent. Mixes are customized at each site based on the vegetation species at that location, making the application as effective as possible.
In most cases, aerial herbicide application is conducted in remote or difficult-to-access locations where interaction with the general public or property owners is minimal. Duke does attempt to notify the property owner if the work plan identifies any potential property hazards or obstacles, or if work proximity or other factors make a notification necessary.
For more information about the specific types of herbicide used, visit Duke Energy’s vegetation management page, here.