The 59-mile-long King line is one of two transmission lines that bring electricity to the Wood River Valley. It runs from near Hagerman to just north of Hailey.
Map courtesy of BLM
Effects on sage grouse habitat are likely to be the primary environmental issue addressed by the BLM when it examines a proposal by Idaho Power Co. to rebuild a 59-mile-long transmission line that serves the Wood River Valley from the southwest.
The 138-kilivolt line extends from the King substation near Hagerman to the Wood River substation near Hailey. It is one of two lines that serve the valley.
The company has submitted an application to renew its right of way for the King line across 28.5 miles of federal land.
The line was built in 1962, and transmission design leader Tris Yerrington said wind blowing across the desert during the intervening decades has fatigued the wire, called the conductors, which now has the potential to break.
Yerrington said Idaho Power plans to rebuild the line with conductors of about double the diameter, which would triple the line’s capacity in anticipation of future growth in electricity demand. He also said the increased capacity would add reliability in case of failure by the Midpoint-Wood River line, which starts near Shoshone. He said that if it is relied on solely, the King line is now about at capacity during times of peak demand in the winter.
A Wood River Electrical Plan, released in 2007 and developed with the help of community representatives, recommended that the King line be rebuilt to 230 kilivolts. However, Idaho Power spokeswoman Lynette Berriochoa said that when that recommendation was made, the anticipated rebuild was quite a bit farther in the future.
“It didn’t seem financially prudent to invest that capital right now,” she said.
In addition to replacing the conductors, the company also proposes to replace the existing wooden poles with steel ones, which would be more fire-resistant. The area is mostly sagebrush-dominated landscape, and scoping documents supplied by the BLM state that wildfires are frequent there.
The new H-shape poles would typically be 5 feet taller than the wooden poles, most of which are between 52 and 65 feet, as well as 5 feet wider at the cross-arms. All but three of the proposed structures would be placed on existing disturbed work pads.
Berriochoa said an additional benefit to the steel poles is that the cross bars are round, rather than square in cross section like the wooden poles, and therefore provide less-appealing nesting sites for raptors in sage grouse habitat.
However, the scoping documents state that because the proposed steel poles cannot be climbed, vehicle access would be necessary for future maintenance. Current access roads are mostly primitive and vary in width between 8 and 14 feet. Idaho Power proposes to make all the roads 14 feet to accommodate construction and maintenance equipment.
That’s a concern to the Idaho Conservation League. Energy Associate Ben Otto said the wider roads are likely to bring more public traffic, and thereby increase fire risk and spread invasive weeds in sage grouse habitat.
“Once an area burns, it’s really hard to get it back to native habitat,” Otto said.
He said the organization will probably recommend that the BLM require Idaho Power to build roads as narrow as possible, decommission those needed only for construction and provide a weed-abatement plan.
Scoping documents state that the proposed project must meet the BLM’s goals for sage grouse and be consistent with mitigation requirements of the Idaho Sage-grouse State Advisory Committee. The documents state that Idaho Power will be required to provide mitigation funding to improve sage grouse habitat in the area at an amount based on the acres impacted by the project and the level of significance.
An environmental assessment is expected to be completed by April 2015, and construction for the two-year-long project is planned to begin later that spring.
The documents state that other than impacts to sage grouse, preliminary issues already raised include the project’s potential impacts on lynx and wolverines, both threatened species; on water quality in the 12 creeks that the line crosses, which include Croy Creek and the Big Wood River; on nesting and brood-rearing periods of migratory birds; on elk and deer during fawning/calving and wintering periods; and regarding invasive plants.
The Twin Falls District of the BLM is seeking public comments on issues that should be addressed by the EA. They can be sent to Dusty Parson, BLM realty specialist, 1387 S. Vinnell Way, Boise, ID 83709, or by email to email@example.com. Comments should be provided by April 8.
An additional opportunity for public comment will be available upon release of the EA next year.
Information about the proposed project may be found at http://blm.gov/htld.