BLM announces preferred route for central Washington transmission line

The Bureau of Land Management (BLM) has announced its preferred route for a new 230-kV transmission line that will serve south-central Washington state’s Yakima Valley, which officials say is needed for reliability reasons.

“Right now, if they suffered an outage of one of the existing lines, they’d have to do some load-shedding in a big hurry to avoid throwing some of the other transmission lines out of commission, [leading to] potential cascading failures,” a BLM spokesperson told TransmissionHub on Jan. 7.

The preferred route for the new Vantage to Pomona Heights line was identified in a draft environmental impact statement (DEIS) that was prepared by the BLM, the U.S. Army Yakima Training Center, U.S. Bureau of Reclamation, the Bonneville Power Administration (BPA), and Grant and Yakima counties and was released for public comment Jan. 4.

The preferred route extends from Pacific Power’s Pomona Heights substation near the town of Selah, Wash., to Vantage, Wash., skirts the U.S. Army’s Yakima Training Center on the south and travels east before heading north toward the town of Mattawa, Wash., to reach the Vantage substation operated by BPA. The distance of the proposed alignment is more than 66 miles.

The 1,046-page DEIS deals with a variety of issues related to construction of the line, including impacts to vegetation, wildlife habitat, agricultural, residential and military land uses, cultural resources, recreational activities, scenic views and transportation.

All of the proposed routes avoid the training center and the Desert Aire area south of the town of Mattawa, primarily because of concerns over aircraft safety. In addition, the state Department of Transportation raised issues about any route that would follow State Route 243 near Desert Aire because of its possible impact on aircraft using the Desert Aire airport.

Portland-based Pacific Power, the project applicant, rejected a proposal to bury the line as too expensive.

The DEIS also deals with concerns about the greater sage grouse, a candidate for listing under the federal endangered species act, as the training center supports one of the two distinct population segments for sage grouse in central Washington.

According to the DEIS, the preferred alternative does not affect as much sage grouse habitat as other alternatives considered. The preferred alternative would also have the least amount of long-term disturbance on residential areas and would minimize impacts on visual and cultural resources.

Pacific Power will construct, operate, and maintain the line, and is seeking right-of-way (ROW) to build the line across a mix of public and private land.

As the lead federal agency on the review, BLM will hold public meetings during the comment period to provide an overview of the project and accept public comments. Comments must be submitted to BLM, by Feb. 19 to be considered in a final environmental document to be released at a later date.

Pacific Power is part of PacifiCorp, a MidAmerican Energy Holdings company.