Document Type: EA-Administrative Record Index Field: Final Environmental Assessment Project Name: Selmer-W. Adamsville 161-kV Transmission Line Project Number: 2012-37 SELMER–WEST ADAMSVILLE 161-KV TRANSMISSION LINE AND SWITCHING STATION ENVIRONMENTAL ASSESSMENT McNairy County, Tennessee Prepared by: TENNESSEE VALLEY AUTHORITY Chattanooga, Tennessee January 2015 Direct Comments to: Anita E. Masters NEPA Program and Valley Projects Tennessee Valley Authority 1101 Market Street Chattanooga, Tennessee 37402 Phone: 423-751-8697 E-mail: [email protected] This page intentionally left blank Contents TABLE OF CONTENTS CHAPTER 1 .......................................................................................................................................... 1 1.1 Proposed Action – Improve Power Supply .............................................................................. 1 1.2 Need for the Proposed Action .................................................................................................. 3 1.3 The Decision ............................................................................................................................ 3 1.4 Other Pertinent Environmental Reviews or Documentation .................................................... 4 1.5 Scoping Process and Public Involvement ................................................................................ 4 1.6 Issues to be Addressed............................................................................................................ 5 1.7 Necessary Federal Permits and Licenses ............................................................................... 7 CHAPTER 2 .......................................................................................................................................... 9 2.1 Alternatives .............................................................................................................................. 9 2.1.1 No Action Alternative – Do Not Construct, Operate, and Maintain a 161-kV Transmission Line and Switching Station ......................................................................... 9 2.1.2 Action Alternative – Construct, Operate, and Maintain a 161-kV Transmission Line and Switching Station ............................................................................................. 10 2.1.3 Other Alternatives Considered but not Selected ............................................................. 11 2.1.3.1 Loop the Colbert-Hickory Valley 161-kV Transmission Line into Pickwick Hydro and Install Capacitors at the Selmer 161-kV Substation ................................ 11 2.1.3.2 Construct a Corinth-Selmer 161-kV Transmission Line and Install Capacitors at the Selmer 161-kV Substation ............................................................ 11 2.2 Construction, Operation, and Maintenance of the Proposed Transmission Line and Switching Station ............................................................................................................. 11 2.2.1 Transmission Line Construction ...................................................................................... 11 2.2.1.1 Right-of-Way Acquisition and Clearing ..................................................................... 11 2.2.1.2 Access Roads ........................................................................................................... 12 2.2.1.3 Construction Assembly/Laydown Area Selection ..................................................... 13 2.2.1.4 Structures and Conductors ....................................................................................... 13 2.2.1.5 Conductor and Ground Wire Installation ................................................................... 14 2.2.2 Switching Station Construction ........................................................................................ 14 2.2.3 Operation and Maintenance ............................................................................................ 16 2.2.3.1 Inspection .................................................................................................................. 16 2.2.3.2 Vegetation Management ........................................................................................... 16 2.2.3.3 Structure Replacement ............................................................................................. 17 2.3 Siting Process ........................................................................................................................ 17 2.3.1 Definition of the Study Area ............................................................................................. 18 2.3.2 Characterization of the Study Area ................................................................................. 18 2.3.2.1 Natural Features ....................................................................................................... 18 2.3.2.2 Cultural Features ....................................................................................................... 18 2.3.2.3 Land Use ................................................................................................................... 18 2.3.2.4 Transportation ........................................................................................................... 19 2.3.3 Data Collection ................................................................................................................ 19 2.3.4 Establishment and Application of Siting Criteria .............................................................. 20 2.3.4.1 Transmission Line Routing Criteria ........................................................................... 20 2.3.4.2 Switching Station Criteria .......................................................................................... 21 2.4 Development of General Route Segments and Potential Transmission Line Routes .................................................................................................................................... 21 2.4.1 Development of Potential Switching Station Sites........................................................... 23 2.4.2 Route Identification and Evaluation ................................................................................. 23 2.5 Comparison of Alternate Transmission Line Routes ............................................................. 24 Environmental Assessment i Selmer-West Adamsville 161-kV Transmission Line 2.5.1 Alternative Transmission Line Routes ............................................................................. 25 2.5.2 Identification of the Preferred Transmission Line Route ................................................. 26 2.6 Comparison of Environmental Effects by Alternative ............................................................. 26 2.7 Identification of Mitigation Measures ...................................................................................... 28 2.8 The Preferred Alternative ....................................................................................................... 29 CHAPTER 3 ........................................................................................................................................ 31 3.1 Groundwater and Geology ..................................................................................................... 31 3.2 Surface Water ........................................................................................................................ 32 3.3 Aquatic Ecology ..................................................................................................................... 33 3.4 Vegetation .............................................................................................................................. 35 3.5 Wildlife .................................................................................................................................... 37 3.6 Endangered and Threatened Species ................................................................................... 38 3.6.1 Aquatic Animals ............................................................................................................... 40 3.6.2 Plants ............................................................................................................................... 40 3.6.3 Terrestrial Animals ........................................................................................................... 41 3.7 Floodplains ............................................................................................................................. 42 3.8 Wetlands ................................................................................................................................ 42 3.9 Aesthetics ............................................................................................................................... 46 3.9.1 Visual Resources ............................................................................................................. 46 3.9.2 Noise ................................................................................................................................ 46 3.9.3 Odors ............................................................................................................................... 46 3.10 Archaeological and Historic Resources ................................................................................. 47 3.11 Recreation, Parks, and Natural Areas ..................................................................................