BONNEVILLE POWER ADMINISTRATION Pacific Direct Current Intertie Upgrade The Dalles, Oregon to the Nevada-Oregon Border Draft Environmental Assessment January 2014 DOE/EA-1937 DOI-BLM-OR-L050-2014-0001-EA Contents CHAPTER 1: PURPOSE OF AND NEED FOR ACTION ........................................................ 1-1 1.1 Introduction ................................................................................................................... 1-1 1.2 Need for Action ............................................................................................................. 1-3 1.3 Purposes of Action ........................................................................................................ 1-3 1.4 Cooperating Agency ...................................................................................................... 1-4 1.5 Public Involvement ....................................................................................................... 1-4 1.5.1 Scoping and Issue Summary ........................................................................................................... 1-4 CHAPTER 2: PROPOSED ACTION AND ALTERNATIVES .................................................. 2-1 2.1 Proposed Action ............................................................................................................ 2-1 2.1.1 Existing Right-of-Way and Transmission Line ............................................................................... 2-4 2.1.2 Upgrade Activities ........................................................................................................................... 2-9 2.1.3 Construction Schedule ................................................................................................................... 2-15 2.1.4 Ongoing Maintenance and Vegetation Management ..................................................................... 2-16 2.2 No Action Alternative ................................................................................................. 2-17 2.3 Alternatives Considered But Eliminated From Detailed Study .................................. 2-17 2.4 Comparison of Alternatives ........................................................................................ 2-18 CHAPTER 3: AFFECTED ENVIRONMENT, ENVIRONMENTAL CONSEQUENCES, AND MITIGATION MEASURES ................................................................................................. 3-1 3.1 Introduction ................................................................................................................... 3-1 3.2 Land Use and Recreation .............................................................................................. 3-3 3.2.1 Affected Environment ..................................................................................................................... 3-3 3.2.2 Environmental Consequences – Proposed Action ........................................................................... 3-8 3.9 Potential impacts to sensitive habitats, visual quality, and cultural resources are addressed in Sections 3.4, Upland Vegetation, 1.1, ............................................................... 3-11 3.9.1 Mitigation – Proposed Action ....................................................................................................... 3-13 Draft Environmental Assessment Page i BPA PDCI Upgrade January 2014 3.9.2 Unavoidable Impacts Remaining after Mitigation – Proposed Action .......................................... 3-14 3.9.3 Environmental Consequences – No Action ................................................................................... 3-14 3.10 Geology and Soils .................................................................................................... 3-15 3.10.1 Affected Environment ................................................................................................................... 3-15 3.10.2 Environmental Consequences – Proposed Action ......................................................................... 3-19 3.10.3 Mitigation – Proposed Action ....................................................................................................... 3-22 3.10.4 Unavoidable Impacts Remaining after Mitigation – Proposed Action .......................................... 3-22 3.10.5 Environmental Consequences – No Action ................................................................................... 3-23 3.4 Upland Vegetation ....................................................................................................... 3-25 3.4.1 Affected Environment ................................................................................................................... 3-25 3.4.2 Environmental Consequences – Proposed Action ......................................................................... 3-40 3.4.3 Mitigation – Proposed Action ....................................................................................................... 3-51 3.4.4 Unavoidable Impacts Remaining after Mitigation – Proposed Action .......................................... 3-54 3.4.5 Environmental Consequences – No Action ................................................................................... 3-54 3.5 Wildlife ........................................................................................................................ 3-55 3.5.1 Affected Environment ................................................................................................................... 3-55 3.5.2 General Wildlife by Ecoregion ...................................................................................................... 3-55 3.5.3 Special Status Species or Habitats ................................................................................................. 3-56 3.5.4 Environmental Consequences – Proposed Action ......................................................................... 3-64 3.5.5 Mitigation – Proposed Action ....................................................................................................... 3-69 3.5.6 Unavoidable Impacts Remaining after Mitigation – Proposed Action .......................................... 3-72 3.5.7 Environmental Consequences – No Action ................................................................................... 3-72 3.6 Fish and Water Resources ........................................................................................... 3-73 3.6.1 Surface Water Affected Environment ........................................................................................... 3-73 3.6.2 Special Status Fish Species or Habitat Affected Environment ...................................................... 3-81 3.6.3 Groundwater Affected Environment ............................................................................................. 3-82 3.6.4 Environmental Consequences – Proposed Action ......................................................................... 3-83 3.6.5 Mitigation – Proposed Action ....................................................................................................... 3-89 Page ii Draft Environmental Assessment January 2014 BPA PDCI Upgrade 3.6.6 Unavoidable Impacts Remaining after Mitigation – Proposed Action .......................................... 3-91 3.6.7 Environmental Consequences – No Action ................................................................................... 3-91 3.7 Wetlands ...................................................................................................................... 3-93 3.7.1 Affected Environment ................................................................................................................... 3-93 3.7.2 Environmental Consequences – Proposed Action ......................................................................... 3-94 3.7.3 Mitigation – Proposed Action ....................................................................................................... 3-95 3.7.4 Unavoidable Impacts Remaining after Mitigation – Proposed Action .......................................... 3-95 3.7.5 Environmental Consequences – No Action ................................................................................... 3-96 3.8 Floodplains .................................................................................................................. 3-97 3.8.1 Affected Environment ................................................................................................................... 3-97 3.8.2 Environmental Consequences – Proposed Action ......................................................................... 3-97 3.8.3 Mitigation – Proposed Action ....................................................................................................... 3-98 3.8.4 Unavoidable Impacts Remaining after Mitigation – Proposed Action .......................................... 3-99 3.8.5 Environmental Consequences – No Action ................................................................................... 3-99 3.9 Visual Quality ........................................................................................................... 3-101 3.9.1 Affected Environment ................................................................................................................. 3-101 3.9.2 Environmental Consequences – Proposed Action ....................................................................... 3-105 3.9.3 Mitigation – Proposed Action 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