Ground wire stringing on the Columbia River complete after weather, supply chain and bird delays

BPA transmission line maintenance crews from The Dalles, Alvey, Redmond and Ross districts recently completed an emergency overhead ground wire replacement operation across the Columbia River, restringing lines damaged during a January 2023 storm.

The damaged ground wire was located on the North Bonneville-Troutdale No. 1 transmission line, where it crosses the Columbia River between Camas, Washington, and Troutdale, Oregon. Due to the age of the ground wire on the North Bonneville-Troutdale No. 2 line, it was decided to replace the ground wire on that line at the same time.  

Two ground wires are on each line and located at the top of the transmission towers to protect transmission structures from lightning. The winter storm knocked one of the four ground wires free, leaving the towers only partially protected. Airway lights on the towers were also out of service because they receive power through the specific ground wire that was damaged.

“From an air navigation and maritime navigation perspective, replacing the ground wire restores a factor of safety back to towers,” said project manager Andrew Young.

Crews were initially on the scene following the storm to remove the downed ground wire but were unable to complete the repair and replacement at the time. Bad weather and supply chain issues pushed the full repairs to summer 2023. Additionally, design and construction plans needed to be assembled.

A plan was developed to restring the ground wire at eight structures along the two parallel transmission lines. Insulators and assemblies for the conductors would also be replaced. A helicopter would be brought in to assist in installing the ground wire across the river, as well as transport equipment and materials from a staging area 0.25 miles away to the tops of the towers. BPA crews would access structures in the Columbia River by boat, climbing the towers to string the lines. In addition, staging areas and landing zones had to be coordinated with local entities such as Georgia Pacific and the Knife River Cement Company. 

As the July construction date moved closer, a new problem emerged. Cormorants decided to roost on the towers. Cormorants are not endangered, but they are protected by the Migratory Bird Treaty Act.  

“The quantity of birds surprised me,” said Young. “There were over 40 nests and close to 100 birds, including chicks that were not yet able to fly, on the two towers in the middle of the Columbia River.” Once again, work was paused until the end of nesting season at the end of August.

With weather, supply chain and birds no longer an issue, work took place in September and finished ahead of the adjusted schedule. 

“The team brought together four crews from different locations, who all do things a little differently,” said Young. “However, it was difficult to distinguish crews from one another since everyone worked extremely well together. Using the helicopter added precautions to an already hazardous job, but things went really smoothly and safely thanks to the professionalism of our crews. Once operations got going, we couldn’t have asked for things to work better than they did.”