SOUTH TABLE WIND PROJECT ENVIRONMENTAL ASSESSMENT DOE/EA 1909 Prepared for U.S. Department of Energy Western Area Power Administration Corporate Services Office Lakewood, Colorado July 2012 EA, South Table Wind Farm Project i TABLE OF CONTENTS Page 1.0 INTRODUCTION .................................................................................................................. 1-1 1.1 BACKGROUND ....................................................................................................... 1-1 1.2 NATIONAL ENVIRONMENTAL POLICY ACT ................................................. 1-1 1.3 PURPOSE AND NEED ............................................................................................ 1-3 1.3.1 Western’s Purpose and Need ..................................................................... 1-3 1.3.2 STW’s Purpose and Need .......................................................................... 1-4 1.4 PUBLIC SCOPING ................................................................................................... 1-5 2.0 ALTERNATIVES, INCLUDING THE PROPOSED ACTION......................................... 2-1 2.1 WESTERN’S PROPOSED ACTION ..................................................................... 2-1 2.2 GEI’s PROPOSED ACTION .................................................................................... 2-1 2.2.1 Road and Turbine Pads .............................................................................. 2-6 2.2.2 Substation.................................................................................................... 2-11 2.2.3 Trenching and Placement of Underground Electrical and Communications Cables .......................................................................... 2-12 2.2.4 Overhead Electrical Power and Communication System ........................ 2-12 2.2.5 Required Marking and Lighting of Wind Turbines ................................. 2-12 2.2.6 O&M Building Construction ..................................................................... 2-13 2.2.7 Final Road Grading, Erosion Control, and Site Cleanup ......................... 2-13 2.2.8 Public Access and Safety ........................................................................... 2-15 2.2.9 Operations and Maintenance ..................................................................... 2-16 2.2.10 Work Force ............................................................................................... 2-17 2.2.11 Traffic........................................................................................................ 2-17 2.2.12 Water Use ................................................................................................. 2-17 2.2.13 Hazardous Materials ................................................................................ 2-17 2.2.14 Reclamation and Decommissioning........................................................ 2-18 2.2.15 GEI-committed Mitigation Measures ..................................................... 2-19 2.2.15.1 Fire Control ............................................................................... 2-19 2.2.15.2 Cultural Resources.................................................................... 2-20 2.2.15.3 Paleontological Resources ....................................................... 2-21 2.2.15.4 Air Quality/Noise ..................................................................... 2-21 2.2.15.5 Vegetation (Including Agricultural Lands) ............................. 2-22 2.2.15.6 Noxious Weeds ......................................................................... 2-22 2.2.15.7 Streams and Wetlands .............................................................. 2-22 2.2.15.8 Soils ........................................................................................... 2-23 2.2.15.9 Wildlife...................................................................................... 2-23 2.2.15.10 Federally Listed Threatened, Endangered, Proposed, and Candidate Species, Migratory Birds, and State-listed Threatened and Endangered Species ..................................... 2-25 2.2.15.11 Sanitation ................................................................................ 2-26 2.2.15.12 Existing Utilities ..................................................................... 2-27 2.2.15.13 Ditches and Culverts .............................................................. 2-27 ii EA, South Table Wind Farm Project TABLE OF CONTENTS (Continued) Page 2.2.15.14 Public Safety ........................................................................... 2-27 2.3 NO ACTION ALTERNATIVE ................................................................................ 2-27 2.4 ALTERNATIVES CONSIDERED BUT ELIMINATED FROM FURTHER CONSIDERATION .............................................................................................. 2-28 2.4.1 Alternative Turbine Locations ................................................................... 2-28 2.4.2 Alternative Project Generation Capacity .................................................. 2-28 2.4.3 Alternate Project Areas .............................................................................. 2-28 3.0 ENVIRONMENTAL ANALYSIS........................................................................................ 3-1 3.1 CLIMATE AND AIR QUALITY ............................................................................ 3-1 3.1.1 Environmental Setting for the Proposed Project ...................................... 3-1 3.1.1.1 Climate ........................................................................................ 3-1 3.1.1.2 Air Quality .................................................................................. 3-2 3.1.2 Environmental Impacts and Mitigation Measures ................................... 3-3 3.1.2.1 Impacts of Western’s Proposed Action ..................................... 3-3 3.1.2.2 Impacts of GEI’s Proposed Action ............................................ 3-3 3.1.2.3 Impacts of the No Action Alternative ....................................... 3-9 3.1.2.4 GEI’s Mitigation Measures ........................................................ 3-9 3.2 GEOLOGY, PALEONTOLOGY, AND SOILS ..................................................... 3-9 3.2.1 Environmental Setting for the Proposed Project ...................................... 3-9 3.2.1.1 Geology and Mineral Resources ................................................ 3-9 3.2.1.2 Paleontology................................................................................ 3-11 3.2.1.3 Soils ............................................................................................. 3-12 3.2.2 Environmental Impacts and Mitigation Measures ................................... 3-12 3.2.2.1 Impacts of Western’s Proposed Action ..................................... 3-12 3.2.2.2 Impacts of GEI’s Proposed Action ............................................ 3-13 3.2.2.3 Impacts of the No Action Alternative ....................................... 3-17 3.2.2.4 GEI’s Mitigation Measures ........................................................ 3-17 3.3 WATER RESOURCES ............................................................................................. 3-17 3.3.1 Environmental Setting for the Proposed Project ...................................... 3-17 3.3.1.1 Surface Water Resources ........................................................... 3-17 3.3.1.2 Groundwater Resources ............................................................. 3-19 3.3.2 Environmental Impacts and Mitigation Measures ................................... 3-19 3.3.2.1 Impacts of Western’s Proposed Action ..................................... 3-19 3.3.2.2 Impacts of GEI’s Proposed Action ............................................ 3-20 3.3.2.3 Impacts of the No Action Alternative ....................................... 3-21 3.3.2.4 GEI’s Mitigation Measures ........................................................ 3-21 3.4 FLOODPLAINS, WETLANDS, AND WUS .......................................................... 3-22 3.4.1 Environmental Setting for the Proposed Project ...................................... 3-22 3.4.2 Environmental Impacts and Mitigation Measures ................................... 3-22 3.4.2.1 Impacts of Western’s Proposed Action ..................................... 3-22 EA, South Table Wind Farm Project iii TABLE OF CONTENTS (Continued) Page 3.4.2.2 Impacts of GEI’s Proposed Action ............................................ 3-23 3.4.2.3 Impacts of the No Action Alternative ....................................... 3-23 3.4.2.4 GEI’s Mitigation Measures ........................................................ 3-24 3.5 VEGETATION (INCLUDING NOXIOUS WEEDS) ............................................ 3-24 3.5.1 Environmental Setting for the Proposed Project ...................................... 3-24 3.5.2 Environmental Impacts and Mitigation Measures ................................... 3-26 3.5.2.1 Impacts of Western’s Proposed Action ..................................... 3-26 3.5.2.2 Impacts of GEI’s Proposed Action ............................................ 3-26 3.5.2.3 Impacts of the No Action Alternative ....................................... 3-27 3.5.2.4 GEI’s Mitigation Measures ........................................................ 3-27 3.6 WILDLIFE ................................................................................................................. 3-28 3.6.1 Environmental Setting of the Proposed