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        Supplemental Environmental Impact Statement | Segments 8 and 9








500-kV transmission tower against blue sky

Potential effects to private land

Siting the project on public lands as much as possible 
is a priority for the BLM. 

The BLM does not authorize rights of way or project construction on private land, but NEPA requires that environmental analyses disclose effects to all lands. 

So, analyses like this supplemental EIS make assumptions about where a project would be sited on non-federal lands (State, county, private), recognizing that these analytical assumptions can suggest or 
create expectations for where the project would 
cross private land.

The table at-left shows the number of miles each route alternative as currently drawn would cross private land.  (Click on the graphic to enlarge the image.)

Consult the Draft Supplemental EIS (Table ES-1, 
p. ES-9)
 for a summary of miles crossed for each route alignment and percentage of total miles, by surface ownership. 

Read MORE >

The BLM is preparing a supplemental environmental impact statement (SEIS) analyzing new information associated with segments 8 and 9 of the Gateway West transmission line project.

The Draft SEIS was published on March 11, 2016.  

Comments will be accepted through June 9, 2016.


      mail    BLM, Gateway West Project 
                 1387 S. Vinnell Way, Boise ID 83709


graphic showing miles of private land crossed by each alternative in the draft supplemental EIS

Navigating the document

The Executive Summary provides a stand-alone overview of the Draft Supplemental EIS, including route descriptions and the potential effects of the alternatives.  It may be a good starting point.  Because the detailed effects analysis in Chapters 3 and 4 refers to analysis related to segments 8 and 9 presented in the 2013 Final EIS for the original Gateway West project, it may help to have a copy of the Final EIS open alongside the Draft SEIS as you read. Chapters and sections in the Final EIS and 
Draft SEIS are consistently numbered for easier cross-referencing. 

While you can download the full Draft SEIS document in one file, you may find it easier to open individual chapters or appendices.  The document is offered both ways on the project Documents page.  Please note that some files are very large, and you may see a blank page while they load.  Clicking on this blank page while it is opening may cause the file to stop loading. 

The online navigation guide below features paths into the document based on topics that have been of particular interest during the process so far.  The links in the guide point to sections of the Draft SEIS and Final EIS which relate to the highlighted topic.

 Topics of interest

 Why is the BLM doing a supplemental EIS (SEIS)?  Draft SEIS Executive Summary
 What factors went into developing route alternatives?
 What are the potential impacts to vegetation and plants?
 What impacts to wildlife are analyzed? 
 What about impacts specific to raptors?
 Would the proposed project impact Greater sage-grouse?
 How might the proposed project impact special status species?

 What are potential impacts to historic trails?

 What impacts to cultural resources (besides historic trails) are analyzed? Erratum note
 How would visual resources be impacted?
 Are there potential impacts to ACECs and Lands with wilderness characteristics?
 How might the proposed project affect private land?
 How would potential impacts be mitigated?
 Are there particular mitigation measures for impacts in the Birds of Prey NCA?
 How are engineering and technical issues analyzed?
 How is information developed by the Boise District RAC used in the Draft SEIS?
 What forms of Tribal consultation have occurred?
 Would authorizing the project require land use plan amendments?
 Are routes for Segments 8 & 9 analyzed in the 2013 Final EIS included in the Draft SEIS?
 Are there maps of the routes analyzed?
 Where can I read the document?

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  SCHEDULE at a glance
¦ Notice of Intent  09.19.2014
¦ Scoping  closed 10.24.2014
¦ Draft Supp. EIS  03.11.2016
Public comment 06.09.2016
  Final Supplemental EIS
  Protest period (+30 days)
  Record of Decision


 vintage photo Morley Nelson working on a transmission line tower

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  Factors in developing alternatives include:

      - conflicts with agriculture 
      - military operations areas 
      - private property/communities 
      - cultural/historic resources 
      - Greater sage-grouse/habitat 
      - road construction needs 
      - sensitive species 
      - Birds of Prey NCA 

                                                        Read MORE >

Google Earth view of proposed route crossing Snake River Canyon