Project No. 1971-079
Commission staff prepared a final supplemental Environmental Impact Statement (SEIS) that supplements the final environmental impact statement (EIS), issued August 31, 2007, for the proposed relicensing of Idaho Power Company’s (Idaho Power) existing Hells Canyon Hydroelectric Project No. 1971 (project).
On July 29, 2003, Idaho Power filed an application for a new license to continue to operate and maintain the project, which is located on the Snake River in Washington and Adams Counties, Idaho, and Wallowa, Malheur and Baker Counties, Oregon. The project consists of three developments (Brownlee, Oxbow, and Hells Canyon), which combined have an installed capacity of 1,222.3 megawatts. The project occupies a total of 5,270 acres of federal land administered by the U.S. Bureau of Land Management and the U.S. Department of Agriculture, Forest Service (Forest Service).
On December 30, 2019, Idaho Power filed an Offer of Settlement and Stipulation and Implementation Agreement (2019 Settlement), resolving disputed issues related to spring Chinook salmon and summer steelhead passage and reintroduction with the states of Oregon and Idaho in the context of their respective water quality certifications under section 401 of the Clean Water Act (401 certifications) for the project. Pursuant to the 2019 Settlement, the states of Oregon and Idaho each issued 401 certifications for the project on May 24, 2019. On July 8, 2020, Idaho Power filed a supplement to its license application that included new and revised environmental measures proposed under the 2019 Settlement, additional refinements to the proposed action, and new information on project-affected resources. Pursuant to the Endangered Species Act (ESA), Idaho Power filed revised draft biological assessments for federally listed species managed by the U.S. Fish and Wildlife Service (FWS) and the National Marine Fisheries Service (NMFS) on October 14, 2020, which were subsequently revised in July 1 and July 16, 2025, filings. On October 23, 2024, Idaho Power filed a settlement agreement on behalf of itself and the Forest Service (2024 Settlement), resolving between the parties the appropriate terms and conditions pursuant to section 4(e) of the Federal Power Act to be incorporated into any new license issued for the project for the protection and utilization of federal lands administered by the Forest Service.
Commission staff prepared a final SEIS to evaluate the proposed project in accordance with filings made subsequent to the issuance of the final EIS, including new and revised proposed measures, the 2019 and 2024 Settlements, and mandatory conditions (i.e., modified Forest Service 4(e) conditions and 401 certification conditions). The final SEIS also addresses the effects of the new and revised measures on federally listed species and their designated critical habitats.
The primary environmental issues associated with relicensing the project are the effects of continued project operation on: (1) sediment supply and transport; (2) water quantity, including navigation in the Snake River downstream of Hells Canyon Dam; (3) water quality; (4) aquatic resources, including the feasibility of restoring runs of anadromous fish to areas upstream of Hells Canyon Dam; (5) terrestrial resources; (6) cultural resources; and (7) the adequacy of recreational facilities to meet expected demand over the term of any new license issued for the project.
In the final SEIS, Commission staff recommends relicensing the project under the Staff Alternative, which includes most of Idaho Power’s proposed measures, as well as certain mandatory conditions and recommendations made by state and federal agencies and some staff-recommended modifications to further minimize project-related effects on aquatic and terrestrial resources, threatened and endangered species, recreation resources, and cultural resources.