BLM United States Department of the Interior Bureau of Land Management Environmental Assessment DOI-BLM-UT-W010-2009-0026-EA July 2018 Skull Valley Land Exchange UTU-89605FD/PT (Note: Original BLM serial number UTU-81900FD/PT) West Desert District Office Location: Skull Valley, Tooele County, Utah Applicant/Address: Castle Rock Land and Livestock Company, a Utah general partnership, and Skull Valley Company, Ltd., a Utah limited partnership – Salt Lake FieldOffice West Desert District Office Salt Lake Field Office 2370 South Decker Lake Boulevard West Valley City, Utah 84119 Phone: (801) 977-4300 Fax: (801) 977-4397 Environmental Assessment DOI-BLM-UT-W010-2009-0026-EA TABLE OF CONTENTS 1.0 —PURPOSE AND NEED ..................................................................................................... 1-1 1.1 Introduction .................................................................................................................. 1-1 1.2 Background .................................................................................................................. 1-1 1.3 Purpose and Need ........................................................................................................ 1-2 1.4 Conformance with BLM Land Use Plan ..................................................................... 1-2 1.4.1 Proposed Action ..................................................................................................... 1-2 1.4.2 No Action Alternative ............................................................................................ 1-3 1.5 Relationship to Statutes, Regulations, Plans and Supporting Documentation............. 1-3 1.6 Decision to Be Made .................................................................................................... 1-6 1.7 Identification of Issues ................................................................................................. 1-6 1.7.1 Cultural Resources ................................................................................................. 1-6 1.7.2 Fuels and Fire Management ................................................................................... 1-6 1.7.3 Invasive Species/Noxious Weeds .......................................................................... 1-6 1.7.4 Livestock Grazing .................................................................................................. 1-7 1.7.5 Mineral Resources ................................................................................................. 1-7 1.7.6 Recreation .............................................................................................................. 1-7 1.7.7 Special Status Animal Species Including Migratory Birds.................................... 1-7 1.7.8 Special Status Plant Species (Pohl’s Milkvetch) ................................................... 1-7 1.7.9 Water Rights .......................................................................................................... 1-7 1.7.10 Wildlife Excluding Special Status Species ............................................................ 1-7 1.7.11 Wilderness and Wilderness Characteristics ........................................................... 1-7 1.7.12 Wild Horse Herd Areas and Herd Management Areas .......................................... 1-8 1.8 Issues Considered but Eliminated from Further Analysis ........................................... 1-8 2.0 —DESCRIPTION OF ALTERNATIVES ............................................................................ 2-1 2.1 Introduction .................................................................................................................. 2-1 2.2 Alternative A – Proposed Action (Exchange) ............................................................. 2-1 2.3 Alternative B – No Action (status quo/no exchange) .................................................. 2-8 2.4 Alternatives Considered, but Eliminated from Further Analysis................................. 2-8 2.4.1 Purchase ................................................................................................................. 2-8 2.4.2 Sale ......................................................................................................................... 2-8 2.4.3 Other Configurations ............................................................................................. 2-9 3.0 —AFFECTED ENVIRONMENT ......................................................................................... 3-1 3.1 Introduction .................................................................................................................. 3-1 3.2 General Setting............................................................................................................. 3-1 3.3 Potentially Affected Resources/Issues ......................................................................... 3-2 3.3.1 Cultural Resources ................................................................................................. 3-2 3.3.2 Fire and Fuels Management ................................................................................... 3-8 3.3.3 Invasive Species/Noxious Weeds .......................................................................... 3-9 i Environmental Assessment DOI-BLM-UT-W010-2009-0026-EA 3.3.4 Livestock Grazing .................................................................................................. 3-9 3.3.5 Mineral Resources ............................................................................................... 3-11 3.3.6 Recreation ............................................................................................................ 3-13 3.3.7 Special Status Animal Species Including Migratory Birds.................................. 3-16 3.3.8 Special Status Plants (Pohl’s Milkvetch) ............................................................. 3-22 3.3.9 Water Rights ........................................................................................................ 3-22 3.3.10 Wildlife Excluding Special Status Species .......................................................... 3-23 3.3.11 Wilderness and Wilderness Characteristics ......................................................... 3-24 3.3.12 Wild Horse Herd Areas and Herd Management Areas ........................................ 3-25 4.0 —ENVIRONMENTAL IMPACTS....................................................................................... 4-1 4.1 Introduction .................................................................................................................. 4-1 4.2 General Analysis Assumptions and Guidelines ........................................................... 4-1 4.3 Direct and Indirect Impacts .......................................................................................... 4-2 4.3.1 Alternative A – Proposed Action ........................................................................... 4-2 4.3.1.1 Cultural Resources .......................................................................................... 4-2 4.3.1.2 Fire and Fuels Management ........................................................................... 4-3 4.3.1.3 Invasive Species/Noxious Weeds ................................................................... 4-3 4.3.1.4 Livestock Grazing ........................................................................................... 4-3 4.3.1.5 Mineral Resources .......................................................................................... 4-4 4.3.1.6 Recreation ....................................................................................................... 4-5 4.3.1.7 Special Status Animal Species including Migratory Birds ............................ 4-7 4.3.1.8 Special Status Plants (Pohl’s Milkvetch) ...................................................... 4-10 4.3.1.9 Water Rights ................................................................................................. 4-11 4.3.1.10 Wildlife Excluding Special Status Species ................................................... 4-11 4.3.1.11 Wilderness and Wilderness Characteristics .................................................. 4-12 4.3.1.12 Wild Horse Herd Areas and Herd Management Areas ................................ 4-13 4.3.1.13 Mitigation Measures ..................................................................................... 4-14 4.3.1.14 Residual Impacts........................................................................................... 4-15 4.3.1.15 Monitoring and/or Compliance .................................................................... 4-15 4.3.2 Alternative B – No Action ................................................................................... 4-16 4.3.2.1 Cultural Resources ........................................................................................ 4-16 4.3.2.2 Fire and Fuels Management ......................................................................... 4-16 4.3.2.3 Invasive Species/Noxious Weeds ................................................................. 4-16 4.3.2.4 Livestock Grazing ......................................................................................... 4-16 4.3.2.5 Mineral Resources ........................................................................................ 4-16 4.3.2.6 Recreation ..................................................................................................... 4-16 4.3.2.7 Special Status