Project Location
Goldendale,
WA
Client
Bonneville Power Administration
Market Sector
Project Type
- Construction Management & Inspection
Services Provided
The Challenge
Aging infrastructure and increasing energy demand in the Pacific Northwest meant the existing 500kV transmission line between Big Eddy and Knight Substation required major upgrades. The corridor, spanning the Columbia River Gorge, posed environmental, cultural, and logistical challenges, particularly at the river crossing where sensitive lands and tribal interests required careful stewardship.
The Challenge
Aging infrastructure and increasing energy demand in the Pacific Northwest meant the existing 500kV transmission line between Big Eddy and Knight Substation required major upgrades. The corridor, spanning the Columbia River Gorge, posed environmental, cultural, and logistical challenges, particularly at the river crossing where sensitive lands and tribal interests required careful stewardship.
The Approach
MacKay Sposito provided comprehensive construction audit and inspection services. Our role was pivotal in ensuring that every aspect of the build, from structural integrity to cultural compliance, met the highest standards. By leveraging our deep regulatory knowledge and field expertise, we helped navigate the project through a complex web of federal, state, and tribal coordination.
The Approach
MacKay Sposito provided comprehensive construction audit and inspection services. Our role was pivotal in ensuring that every aspect of the build, from structural integrity to cultural compliance, met the highest standards. By leveraging our deep regulatory knowledge and field expertise, we helped navigate the project through a complex web of federal, state, and tribal coordination.
The Work
Our team supported replacing 29 miles of double-circuit 500kV lattice steel transmission line. Services included inspection of access road installations, drilling and blasting for foundations, erection of lattice steel towers, fall protection systems, conductor installation, and fiber optic cable splicing and testing. We ensured compliance with project specs during excavation and steel placement and performed final tower climbing inspections before turnover.
As one of the project contributors notes, “A thorough environmental and cultural analysis was developed, implemented, and monitored at the River Crossing to minimize or eliminate any impact construction activities may have on the land and a nearby cultural resource.
Our firm coordinated efforts across numerous agencies and stakeholders, including the Federal Aviation Administration (FAA), United States Coast Guard, Oregon Department of Transportation (ODOT), Washington State Department of Transportation (WSDOT), BNSF Railway, and the Yakama Nation.
The Impact
The rebuilt Big Eddy–Knight transmission line strengthens the reliability of the regional power grid and supports long-term energy delivery across the Pacific Northwest. This project utilized an innovative, trapezoidal wire conductor, which placed this project at the forefront of transmission efficiency advancements. Its smaller diameter and aluminum-clad steel core made it easier and more cost-effective to install, while reducing environmental impact along sensitive corridors. The conductor’s compact design increased surface area for current flow, enabling greater electrical capacity without enlarging tower structures; a significant innovation at the time.
Care and rigorous planning and communication ensured the environmental and cultural resources along the Columbia River were protected while enhancing service stability for surrounding communities, utilities, and industrial users. This project demonstrates how infrastructure improvement can advance energy resilience and responsible land stewardship.
