Keeler-to-Tillamook Transmission Line Rebuild Project Draft Environmental Assessment October 2013 This page deliberately left blank. Contents Chapter 1 Purpose and Need for Action ............................................................................................ 1-1 1.1 Introduction ................................................................................................................................. 1-1 1.2 Need for Action ............................................................................................................................ 1-1 1.3 Purposes of Action ....................................................................................................................... 1-2 1.4 Public Involvement and Issue Summary ...................................................................................... 1-2 Chapter 2 Proposed Action and Alternatives .................................................................................... 2-1 2.1 Proposed Action ........................................................................................................................... 2-1 2.1.1 Existing Transmission Line and Right-of-Way .......................................................................... 2-6 2.1.2 Transmission Line Structures ................................................................................................... 2-6 2.1.3 Conductors, Overhead Ground Wires, and Counterpoise ....................................................... 2-8 2.1.4 Access Roads ............................................................................................................................ 2-8 2.1.5 Construction Activities ............................................................................................................. 2-9 2.1.6 Vegetation Management ....................................................................................................... 2-13 2.1.7 Operation and Maintenance .................................................................................................. 2-13 2.1.8 Steel Pole Replacement ......................................................................................................... 2-14 2.2 No Action Alternative ................................................................................................................. 2-15 2.3 Alternatives Considered but Eliminated from Detailed Study ................................................... 2-15 2.4 Comparison of Alternatives ....................................................................................................... 2-16 Chapter 3 Affected Environment and Environmental Consequences ............................................... 3-1 3.1 Introduction ................................................................................................................................. 3-1 3.2 Land Use, Recreation, and Transportation .................................................................................. 3-2 3.2.1 Affected Environment .............................................................................................................. 3-2 3.2.2 Environmental Consequences–Proposed Action ................................................................... 3-12 3.2.3 Mitigation—Proposed Action ................................................................................................ 3-18 3.2.4 Unavoidable Impacts after Mitigation—Proposed Action ..................................................... 3-19 3.2.5 Cumulative Impacts—Proposed Action ................................................................................. 3-19 3.2.6 Environmental Consequences–No Action Alternative ........................................................... 3-20 3.3 Geology and Soils ....................................................................................................................... 3-21 3.3.1 Affected Environment ............................................................................................................ 3-21 3.3.2 Environmental Consequences–Proposed Action ................................................................... 3-27 3.3.3 Mitigation–Proposed Action .................................................................................................. 3-31 3.3.4 Unavoidable Impacts after Mitigation–Proposed Action ...................................................... 3-32 3.3.5 Cumulative Impacts–Proposed Action ................................................................................... 3-32 3.3.6 Environmental Consequences–No Action Alternative ........................................................... 3-33 Bonneville Power Administration i Contents 3.4 Fish ............................................................................................................................................. 3-34 3.4.1 Affected Environment ............................................................................................................ 3-34 3.4.2 Environmental Consequences–Proposed Action ................................................................... 3-37 3.4.3 Mitigation–Proposed Action .................................................................................................. 3-42 3.4.4 Unavoidable Impacts after Mitigation–Proposed Action ...................................................... 3-43 3.4.5 Cumulative Impacts–Proposed Action ................................................................................... 3-43 3.4.6 Environmental Consequences–No Action Alternative ........................................................... 3-44 3.5 Wildlife ....................................................................................................................................... 3-45 3.5.1 Affected Environment ............................................................................................................ 3-45 3.5.2 Environmental Consequences–Proposed Action ................................................................... 3-51 3.5.3 Mitigation–Proposed Action .................................................................................................. 3-58 3.5.4 Unavoidable Impacts after Mitigation–Proposed Action ...................................................... 3-60 3.5.5 Cumulative Impacts–Proposed Action ................................................................................... 3-60 3.5.6 Environmental Consequences–No Action Alternative ........................................................... 3-60 3.6 Vegetation .................................................................................................................................. 3-62 3.6.1 Affected Environment ............................................................................................................ 3-62 3.6.2 Environmental Consequences–Proposed Action ................................................................... 3-66 3.6.3 Mitigation–Proposed Action .................................................................................................. 3-69 3.6.4 Unavoidable Impacts after Mitigation–Proposed Action ...................................................... 3-71 3.6.5 Cumulative Impacts–Proposed Action ................................................................................... 3-71 3.6.6 Environmental Consequences–No Action Alternative ........................................................... 3-72 3.7 Waterways, Water Quality, and Floodplains ............................................................................. 3-73 3.7.1 Affected Environment ............................................................................................................ 3-73 3.7.2 Environmental Consequences–Proposed Action ................................................................... 3-83 3.7.3 Mitigation–Proposed Action .................................................................................................. 3-91 3.7.4 Unavoidable Impacts after Mitigation–Proposed Action ...................................................... 3-92 3.7.5 Cumulative Impacts–Proposed Action ................................................................................... 3-93 3.7.6 Environmental Consequences–No Action Alternative ........................................................... 3-94 3.8 Wetlands .................................................................................................................................... 3-95 3.8.1 Affected Environment ............................................................................................................ 3-95 3.8.2 Environmental Consequences–Proposed Action ................................................................... 3-98 3.8.3 Mitigation–Proposed Action ................................................................................................ 3-107 3.8.4 Unavoidable Impacts after Mitigation–Proposed Action .................................................... 3-108 3.8.5 Cumulative Impacts–Proposed Action ................................................................................. 3-108 3.8.6 Environmental Consequences–No Action Alternative ......................................................... 3-109 3.9 Visual Resources ...................................................................................................................... 3-110 3.9.1 Affected Environment 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