The Bonneville Power Administration (BPA) has decided to construct and operate the Hooper Springs Transmission Project in Caribou County, Idaho. This project consists of constructing a new Hooper Springs Substation; a new, approximately 24-mile-long, double-circuit 115-kilovolt (kV) transmission line between Hooper Springs Substation and a BPA connection facility with Lower Valley Energy's existing transmission system; a new, approximately 0.2-mile-long, single-circuit 138-kV transmission line between Hooper Springs Substation and PacifiCorp's existing Threemile Knoll Substation; and required ancillary facilities such as access roads. The new 24-mile-long, double-circuit 115-kV transmission line will be constructed along Option 3A. The Hooper Springs Transmission Project will improve system reliability in the southern portion of Lower Valley Energy's transmission system and will address ongoing load growth in southeast Idaho and in northwestern Wyoming. 

Two route alternatives were considered for the project: a North Alternative, including two route options and a South Alternative, including five route options. BPA also considered a No Action Alternative in which BPA would not have constructed the substation, transmission lines, or ancillary facilities. 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 is the lead agency for preparation of the environmental impact statement (EIS). The U.S. Forest Service, Caribou-Targhee National Forest, U.S. Bureau of Land Management, and the State of Idaho's Office of Energy Resources are cooperating agencies and have assisted with preparation of the environmental impact statement, including assisting BPA in evaluating transmission line alternatives and identifying issues that were 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 Lower Valley Energy'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 Lower Valley Energy 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 released the final EIS in January 2015. The final EIS describes the project and why it is needed, discusses the environmental impacts the project will create, lists the mitigation measures that will lessen or eliminate those impacts, and addresses comments received on the draft and supplemental draft EISs. Impacts are disclosed for the following resources: land use, recreation, visual resources, vegetation, soils, water resources, wetlands and floodplains, wildlife, fish, cultural resources, socioeconomics, transportation, noise, public health and safety, air quality, and greenhouse gases.


The Record of Decision (ROD) was signed on March 16, 2015. As described above, BPA has decided to construct the project using Option 3A. Project activities in 2017 will include acquisition of land rights with substation, transmission line, and access road construction beginning in late summer 2017.


For environmental information, contact:
Carol Leiter Toll-free: 800-622-4519
Supervisory Environmental Protection Specialist Direct line: 360-418-8608
Bonneville Power Administration - ECT-4 Email: 
P.O. Box 3621
Portland, OR 97208-36211

For project information, contact:
Erich Orth        Toll-free: 800-622-4519
Project Manager Direct line: 360-619-6559
Bonneville Power Administration - TEP-TPP-3 Email: 
P.O. Box 61409
Vancouver, WA 98666-1409


Public Letter (04/01/2015)
Record of Decision (03/16/2015)

Public Letter (01/13/2015)
Final EIS (January 2015)

Supplemental Draft EIS comments received
Public Letter (05/01/2014)
Supplemental Draft EIS Volume 1: Environmental Impact Statement (May 2014)
Supplemental Draft EIS Volume 2: Comments and Responses to the Draft EIS (May 2014)
Supplemental Draft EIS Volume 3: Appendices (May 2014)
Comment Form (05/01/2014)


BPA Geotechnical Counterpoise Investigations (08/27/2014)

Public Letter (10/22/2013)
Project Map - update (09/13/2013)
Public Letter - update (06/27/2013)

Draft EIS comments received
Public Letter (02/27/2013)
Draft EIS Volume 1: Environmental Analysis (March 2013)
Draft EIS Volume 2: Appendices (March 2013)
Draft EIS Comment Form (02/27/2013)

Scoping comments received
Public Scoping Letter (06/30/2010)
Comment Form (06/30/2010)

Notice of Intent (06/29/2010)
Preliminary Project Map (June 2010)

Environmental Assessment (EA)
EA comments received
Public Letter Announcing Preliminary EA (05/12/2009)
Comment Form (May 2009)
Preliminary EA (May 2009)

Figures not embedded in the Preliminary EA
Figure 1 Project Vicinity
Figure 2 Map Book Index and Map Sheets
Figure 11 Water Resources
Figure 12 Land Use
Figure 13 Visual Resources

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 (06/18/2007)
Public Letter (06/16/2006)
Open House Information (June 2006)
Comments from Open House (June 2006)
Project Map (05/24/2006)
EA Determination (April 2006)
Map of Southeast Idaho Electrical System (July 2003)