CONTENTS EXECUTIVE SUMMARY ............................................................Immediately after CONTENTS Chapter 1. PURPOSE AND NEED............................................................................................... 8 1.1. Introduction......................................................................................................................... 8 1.2 Project Summary................................................................................................................. 9 1.3 Purpose and Need ............................................................................................................. 17 1.3.1 Applicant’s Purpose and Need.......................................................................................... 17 1.3.2 The Department of Energy’s Purpose and Need............................................................... 22 1.3.3 Purpose of Environmental Assessment............................................................................. 23 1.4 Detail of Proposed Project ................................................................................................ 24 1.4.1 Purchase and Use of Citizens’ Communications Transmission Assets............................ 24 1.4.2 Mosher’s Tap to Irasburg 115/48kV Double Circuit Build.............................................. 27 1.4.3 Highgate Expansion.......................................................................................................... 28 1.4.4 Improvements at Other Substations.................................................................................. 30 1.5 State Proceedings.............................................................................................................. 31 Chapter 2. PROPOSED ACTION AND ALTERNATIVES ....................................................... 33 2.1 Proposed Action...................................................................................................................... 33 2.1.1 Proposed Route................................................................................................................. 34 Irasburg to Mosher’s Tap............................................................................................ 34 Description of Preferred Alternative Route................................................................ 36 2.1.2 Line Design Specifications and Support Structure ........................................................... 38 Irasburg to Mosher’s Tap............................................................................................ 38 Highgate Line..............................................................................................................41 Substation Design ......................................................................................................44 Irasburg ...................................................................................................................... 44 St. Johnsbury............................................................................................................... 45 1 Highgate...................................................................................................................... 46 St. Albans.................................................................................................................... 49 2.2 Alternative Routes for the Double-Circuit Line from Mosher’s Tap to Irasburg............. 50 2.2.1 Alternative Route Options................................................................................................ 50 New Corridor Alternative:................................................................................................ 52 Partially New Corridor:.....................................................................................................54 2.3 Comparison of the Proposed Route (Preferred Alternative) and Alternative Routes....... 55 2.4 Alternative Line and Substation Designs.......................................................................... 56 2.4.1 Alternative Conductor and Pole Size................................................................................ 56 2.4.2 Undergrounding the Transmission Line ........................................................................... 61 2.4.3 Alternative Substation Designs......................................................................................... 62 2.4.4 Comparison of the Proposed Design and Alternative Designs......................................... 63 2.5 Alternatives to the Proposed Project................................................................................. 64 2.5.1 The No Action Alternative................................................................................................ 64 2.5.2 The Generation Alternative............................................................................................... 66 2.5.3 The Conservation, Fuel Conversion, Demand-Side Management Alternative................. 68 2.6 Construction Activities ..................................................................................................... 70 2.6.1 Transmission Lines ........................................................................................................... 70 a. Surveying Activities................................................................................................ 71 b. Right-of-way Clearing and Maintenance Practices ................................................ 71 c. Access-Road Construction...................................................................................... 72 d. Pole Installation...................................................................................................... 73 e. Framing and Stringing.............................................................................................74 2.6.2 Substations ........................................................................................................................ 75 Irasburg and St. Johnsbury.......................................................................................... 76 Highgate...................................................................................................................... 76 St. Albans.................................................................................................................... 77 2.6.3 Schedule............................................................................................................................ 77 Chapter 3 AFFECTED ENVIRONMENT .................................................................................. 79 3.1 Climate, Meteorology, and Air Quality ............................................................................ 79 3.1.1 Climate.............................................................................................................................. 79 2 3.1.2 Meteorology...................................................................................................................... 80 3.1.3 Air Quality ........................................................................................................................ 81 3.2 Land Features And Use..................................................................................................... 83 3.2.1 Topography, Seismicity, Bedrock Geology and Soils...................................................... 83 Topography................................................................................................................. 83 Seismicity.................................................................................................................... 84 Bedrock Geology and Soils........................................................................................ 85 3.2.2 Agriculture ........................................................................................................................ 88 3.2.3 Forest Resources ............................................................................................................... 90 3.2.4 Earth Extraction ................................................................................................................ 91 3.2.5 Recreation ......................................................................................................................... 92 3.2.6 Residential, Commercial and Industrial............................................................................ 94 3.2.7 Airports, Navigation, Training Areas, Public Facilities and Other Land Uses................. 97 3.3 Hydrology, Water Quality And Water Use....................................................................... 98 3.3.1 Surface Waters.................................................................................................................. 98 3.3.2 Flood Waters................................................................................................................... 101 3.3.3 Ground Water and Water Supply.................................................................................... 102 3.3.4 Wetlands ......................................................................................................................... 103 3.3.5 Water Quality.................................................................................................................. 105 3.4 Ecology ........................................................................................................................... 106 3.4.1 Vegetation/ Flora ...........................................................................................................