BPA could remove thousands of trees along Eastside transmission lines

The maintenance would affect power lines running from Renton to Monroe.

Bonneville Power Administration is planning to remove hundreds and possibly thousands of trees along a transmission line stretching from Renton to Monroe beginning next month.

The decision comes after Bonneville Power Administration (BPA), a federal energy corporation, reclaimed the line from Puget Sound Energy after a 50-year lease expired last fall. The two companies have different standards and trimming schedules for lines they manage, which means BPA will increase the clearance area around the transmission lines by around 26 feet. This will include removing trees, shrubs and undergrowth along 53 miles of line.

Kevin Wingert, spokesperson for BPA, said they usually remove vegetation even further, up to 75 feet on either side of the center line, for a full clearance of their easement. Clearing plants helps protect the lines from falling trees or from electricity jumping to nearby trees and shrubs beneath. This protects the property and the reliability of the grid. Puget Sound Energy removed vegetation from around 36 feet on either side. BPA has proposed increasing this to 62.5 feet on either side.

Puget Sound Energy also removes trees from around its power lines, but whereas the entity provide service in Washington state, Wingert said BPA provides service across much of the West Coast and maintains around 15,000 miles of line. Puget Sound Energy trims on a yearly schedule while BPA trims in three-year cycles, Wingert said.

“That’s kind of the crux of the story at a really high level as you’re looking at the difference in the line when it was under Puget and the line when it came back to BPA,” he said.

The plan has caused concern among some residents like Thomas Speckhardt whose property just outside Issaquah city limits near Issaquah Christian Church — and a community well that serves several houses — is located near the line. On a recent rainy afternoon, he donned his work boots and walked out to the easement that abuts his backyard. Speckhardt has goats that graze on some of the vegetation.

Speckhardt is worried that the plan, which includes the use of herbicides, could impact his well along with wetlands in the area and run-off that enters nearby streams. At an open house on March 6, Speckhardt said representatives of BPA were asking landowners where wells and other water infrastructure were located.

“It’s just showing that they signed off on this without really realizing what the impact was,” he said.

A system-wide environmental impact statement was completed in 2000 and has been updated for new projects, Wingert said. A supplementary analysis was completed for this project, which includes the Sammamish-Maple Valley Line 1 and the Monroe Novelty Hill Line 1. Wingert said they will not apply herbicide within 162 feet of wellheads and or within 100 feet of wetlands and other bodies of water. However, BPA can apply herbicides within 35 feet of water sources that are not classified as sensitive habitat areas.

An initial estimate of tree loss was pegged at around 3,000 trees if the entire right-of-way were cleared. After hearing concerns from landowners, BPA adjusted its clearing to only 83 percent of its easement, up from around 56 percent that Puget Sound Energy maintained. It isn’t known how many trees would now be affected.

Speckhardt said he was concerned that general BPA clearance standards may not be applicable to these lines, and that a one-size-fits-all approach might not be effective for a line that runs through cities, mountains and countryside.

“Essentially BPA is imposing this internal standard on this 53 miles of line,” he said.

Transmission lines could be put underground, but according to the BPA website, that would cost between $8 million to $12 million per mile, at least 10 times the cost of above-ground structures. If the plan moves ahead, crews could begin clearing vegetation from along the power line’s route in April.

A map of the transmission lines which Bonneville Power Administration is planning on clearing vegetation from. From Bonneville Power Administration

A map of the transmission lines which Bonneville Power Administration is planning on clearing vegetation from. From Bonneville Power Administration