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Hooper Springs Transmission Project (DOE/EIS-0451)

Caribou County, Idaho


    Bonneville Power Administration (BPA) is proposing to build a new 115-kilovolt (kV) transmission line that would extend from BPA's proposed Hooper Springs Substation near the city of Soda Springs, Idaho, to either an existing Lower Valley Energy (LVE) substation or a proposed BPA connection facility that would connect with LVE's existing transmission system in northeastern Caribou County. The new line would be about 22 to 33 miles depending on the route alternative or option. BPA also would construct an approximately 0.2-mile-long 138-kV transmission line between the proposed Hooper Springs Substation and PacifiCorp's existing Threemile Knoll Substation to connect the electrical facilities to the regional transmission grid. The project is needed to improve voltage stability on the transmission grid to meet future load growth in southeast Idaho and northwestern Wyoming.

    Two route alternatives are being considered for the proposed line from the Hooper Springs Substation to the connection with LVE's transmission system: a North Alternative, including two route options and a South Alternative, including five route options. BPA is also considering a No Action Alternative, that is, BPA would not build the transmission line. BPA also considered but eliminated from detailed study several other potential alternatives, including potential non-wire solutions for more information on non-wires, please visit: BPA Non-Wires Initiative Information. BPA has identified the South Alternative's Option 3A as the preferred alternative.

    BPA is the lead agency for preparation of the EIS. The U.S. Forest Service, Caribou-Targhee National Forest (C-TNF), U.S. Bureau of Land Management (BLM), and the State of Idaho's Office of Energy Resources are cooperating agencies and have assisted with preparation of the environmental impact statement (EIS), including assisting BPA in evaluating transmission line alternatives and identifying issues that should be addressed in the EIS.


    In May 2009, BPA issued a preliminary environmental assessment (EA) (DOE/EA-1567) for BPA's proposal to construct, operate, and maintain Hooper Springs Substation and to partially fund LVE's construction, operation, and maintenance of a new 22 mile, 115-kV transmission line. The proposed line considered in the preliminary EA extended from the proposed Hooper Springs Substation generally northeast across C-TNF, BLM, and private lands along the Blackfoot River, connecting with an existing LVE transmission line near the intersection of Blackfoot River Road and Diamond Creek Road.

    Based on comments received on the preliminary EA, BPA discovered that the proposed route identified in the preliminary EA (the current South Alternative) crossed one or more areas that may have selenium soil contamination from phosphate mining activities. Because of environmental and other concerns about these sites, BPA developed the North Alternative for consideration and determined that preparation of an EIS for the project was appropriate. The draft EIS evaluated a North Alternative and two route options, and a South Alternative and four route options.

    After release of the draft EIS, BPA continued to evaluate comments and suggestions concerning the alternatives and options. As a result, BPA identified an additional route option for the South Alternative. Because it is largely similar to Option 3, this additional route option has been identified as Option 3A. While similar to South Alternative route options included in the draft EIS, Option 3A was not specifically evaluated in the draft EIS. BPA therefore prepared the supplemental draft EIS to evaluate this route option in detail. BPA released the supplemental draft EIS May 1, 2014 for public review and comment. An open-house public meeting was held on May 27, 2014 in Soda Springs, ID to answer questions and accept comments on the scope of the supplemental draft EIS. The comment period closed August 7, 2014.


    BPA has completed the final EIS which describes the proposed project and the environmental effects expected from construction, operation, and maintenance of the transmission line. The final EIS presents the comments received, BPA's responses to those comments and corrections to the supplemental draft EIS.

    With the final EIS complete, we will next produce a Record of Decision (ROD) that documents BPA's decision about whether to proceed with the project and, if so, which alternative was selected. BPA expects to issue its ROD in early 2015.


  • For environmental information, contact:
    Tish Eaton
    Environmental Protection Specialist
    Bonneville Power Administration - KEC-4
    P.O. Box 3621
    Portland, OR 97208-36211

    Direct line:


    For project information, contact:
    Erich Orth
    Project Manager

    Bonneville Power Administration - TEP-TPP-3
    P.O. Box 61409
    Vancouver, WA 98666-1409

    Direct line:



    (All documents are in pdf format unless otherwise noted)


    Comments received on EA
    Public Letter Announcing Preliminary EA (44 Kb) (05/12/2009)
    Comment Form (18 Kb) (May 2009)
    Preliminary EA (1.50Mb) (May 2009)

    Figures not embedded in the Preliminary EA
    Figure 1 Project Vicinity (653 Kb)
    Figure 2 Map Book Index and Map Sheets (1.60Mb)
    Figure 11 Water Resources (948 Kb)
    Figure 12 Land Use (320 Kb)
    Figure 13 Visual Resources (411 Kb)

    This project was formerly called the Caribou Valley Energy Project. The documents below were released before the project name was changed.

    Photomap of Proposed Transmission Line Route (698 Kb) (6/18/2007)
    Public Letter (34 Kb) (6/16/2006)
    Open House Information (63 Kb) (June 2006)
    Comments from Open House (10 Kb) (June 2006)
    Project Map (1.2MB) (5/24/2006)
    EA Determination (32 Kb) (April 2006)
    Map of Southeast Idaho Electrical System (682 Kb) (July 2003)

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 Page last reviewed on 4/18/2013 1:32:15 PM