Various public and private utilities have been proposing high-voltage transmission improvements, including the regional system provider in the US Pacific Northwest, the Bonneville Power Administration (BPA).
Golder was selected by BPA to assist in the evaluation of, and regulatory compliance for, a 75-mile-long (121 km), 500-kilovolt (kV) transmission line and associated substations proposed for southwest Washington State. The line crosses the Columbia River to a new substation in the state of Oregon. If approved, the I-5 Corridor Reinforcement Project would be the largest 500kV transmission line constructed by BPA in this area in 40 years.
An Environmental Impact Statement (EIS) is required under the US National Environmental Policy Act (NEPA) to evaluate the project and its possible routing alternatives. The process started with Golder studying four alternative alignments totaling approximately 300 miles (483 km).
Potential environmental and social issues identified include land use, cultural resources, aesthetics, public health and safety, sensitive plants and animals, soil erosion, wetlands, floodplains, fish, wildlife and water resources, and environmental justice issues (potential impact on low-income and minority populations). Project aspects to be addressed include construction activities, right-of-way clearing, and impacts of construction and operation of towers, access roads, substations and related facilities.
Golder will work with BPA to finalize the EIS to support a final decision on the project. The line would help to ensure reliability and increase capacity for the overall transmission grid and support local and regional needs in the Northwest and beyond.