Yale Saddle Dam Improvement Project Environmental Assessment and Environmental Impact Statement

Strategic Insights -

The Federal Energy Regulatory Commission has issued an Environmental Assessment (EA) and Environmental Impact Statement (EIS) for the Yale Saddle Dam Improvement Project, part of the Yale Hydroelectric Project, located on the Lewis River in Washington state. The project, operated by PacifiCorp, aims to improve post-earthquake dam stability, addressing seismic stability concerns that have led to the reservoir being maintained 10 feet below the normal operating elevation since 2020. The EA and EIS evaluate the potential environmental impacts of the proposed action and consider alternatives, including a no-action alternative.

Key Takeaways:

  • The Yale Saddle Dam Improvement Project is a non-capacity amendment of the existing license for the Yale Hydroelectric Project, which will address seismic stability concerns and allow for the restoration of the normal operating reservoir elevation.
  • The project involves geotechnical investigations and proposed actions to improve post-earthquake dam stability.
  • The licensee, PacifiCorp, maintains the project reservoir 10 feet below the normal operating elevation as an interim risk reduction measure due to seismic stability concerns.
  • The Commission's Division of Dam Safety and Inspections (D2SI) determined that maintaining the reservoir at this level is an appropriate interim risk reduction measure.
  • The proposed action will remove the need for interim risk reduction measures, allowing for the restoration of the normal operating reservoir elevation in accordance with the project license.
  • The project occupies federal land administered by the U.S. Bureau of Land Management.
  • The proposed action will improve post-earthquake dam stability and reduce the risk of dam failure.

Statistics:

  • The project reservoir is currently maintained 10 feet below the normal operating elevation.
  • The proposed action will restore the normal operating reservoir elevation.
  • The project occupies federal land administered by the U.S. Bureau of Land Management.
  • Geotechnical investigations were conducted in 2020 and 2021 to assess the seismic stability of the Yale saddle dam.
  • The seismically induced liquefaction potential of the foundation material is a primary concern.
  • The proposed action aims to improve post-earthquake dam stability by addressing the seismic stability concerns.

Sources:

  • [Document Accession #: 20250522-3016 Filed Date: 05/22/2025 ENVIRONMENTAL ASSESSMENT NON-CAPACITY AMENDMENT OF LICENSE FOR THE YALE SADDLE DAM IMPROVEMENT PROJECT YALE HYDROELECTRIC PROJECT FERC No. 2071-090]
  • [Washington: Federal Energy Regulatory Commission Office of Energy Projects Division of Hydropower Administration and Compliance 888 First Street, N.E. Washington, DC 20426 May 2025]