TABLE OF CONTENTS 

Environmental Impact Statement 

Continental Divide-Creston 

Natural Gas Development Project 

Volume I 

November 2012 

DRAFT 
The BLM’s multiple-use mission is to sustain the health and productivity of the 

public lands for the use and enjoyment of present and future generations. The 

Bureau accomplishes this by managing such activities as outdoor recreation, 

livestock grazing, mineral development, and energy production, and by 

conserving natural, historical, cultural, and other resources on public lands. 

BLM/WY/PL-13/002+1310
 
 

 

 

Draft Environmental Impact Statement (EIS) 

BP-America Production Company and 20 Other Operators
 

Continental Divide-Creston Natural Gas Development Project 

Lead agency: U.S. Department of the Interior, Bureau of Land Management (BLM) 

Project location: Carbon and Sweetwater Counties, Wyoming 

Comments & further David Simons, Team Lead 

information on the Draft EIS:	 Bureau of Land Management, Rawlins Field Office 

1300 North Third Street 

Rawlins, WY 82301-2407 

Phone: (307) 328-4200 

BLM Authorized Officer Dennis Carpenter, Field Office Manager 

responsible for preparing the 

Draft EIS: 

Abstract 

The Operators propose to develop oil and gas resources within the 1.1 million-acre Continental DivideCreston (CD-C) project area located in Carbon and Sweetwater Counties west of Rawlins, Wyoming. The 

CD-C project is an in-fill project with over 4,400 existing oil and gas wells and associated infrastructure. 

The Proposed Action would include the development of an additional 8,950 gas wells at down to 40-acre 

downhole spacing. Construction would begin after the issuance of the Final EIS and Record of Decision 

and approval of individual Applications for Permit to Drill and/or approved right-of-way grants. 

Construction would require approximately 15 years. The productive life of the project would extend an 

estimated 30 to 40 years beyond that. 

The Proposed Action and five alternatives were analyzed in detail in this Draft EIS. The alternatives are: 

 The Proposed Action; 

 Alternative A, 100-Percent Vertical Drilling; 

 Alternative B, Enhanced Resource Protection;
 

 Alternative C, Surface Disturbance Cap—High and Low Density Development Areas; 

 Alternative D, Directional Drilling; and 

 Alternative E, No Action. 

Under all the action alternatives, the analysis includes impacts produced by development activities on 

federal, state, and private mineral estate. In addition to the applicable BLM environmental protection 

measures listed in Appendix C of the EIS document, mitigation is recommended that would lessen the 

environmental effects of the proposed project. 

Written comments on the Draft EIS will be accepted by the Rawlins Field Office of the BLM throughout 

a 45-day public comment period beginning on the date the United States Environmental Protection 

Agency publishes a Notice of Availability for this EIS. A summary of the comments and responses to the 

comments will be provided in the Final EIS. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 i 
 

 

United States Department of the Interior 

BUREAU OF LAND MANAGEMENT 

High Desert District

 Rawlins Field Office 

P.O. Box 2407 (1300 North Third Street) 

Rawlins, WY 82301-2407
 

In reply refer to: 3160 (WYD03) 

Dear Reader: 

The Draft Environmental Impact Statement (EIS) for the Continental Divide-Creston Natural Gas 

Development Project is available for your review and comment. It was prepared to analyze the potential 

impacts of a proposal from BP America Production Company and others for natural gas field 

development. The Continental Divide-Creston (CD-C) project area encompasses approximately 1.1 

million acres (1,672 square miles) in an existing gas-producing area located west of Rawlins, Wyoming in 

Carbon and Sweetwater Counties. 

The CD-C project is an in-fill project with over 4,400 existing oil and gas wells. The Proposed Action 

includes the development of an additional 8,950 gas wells, including construction of supporting 

infrastructure—access roads, pipelines, electrical power lines, a central gas-processing plant, and water 

management and disposal facilities. Construction would begin after the issuance of the Final EIS and 

Record of Decision and approval of individual Applications for Permit to Drill and/or approved right-ofway grants. Construction would require approximately 15 years. The productive life of the project would 

extend an estimated 30 to 40 years beyond that, for a combined total project life of 45 to 55 years. 

This Draft EIS analyzes the Proposed Action and the following five alternatives in detail: 

 Alternative A, 100-Percent Vertical Drilling; 

 Alternative B, Enhanced Resource Protection; 

 Alternative C, Surface Disturbance Cap—High and Low Density Development Areas; 

 Alternative D, Directional Drilling; and 

 Alternative E, No Action. 

Total new surface disturbance under the Proposed Action would be approximately 47,200 acres, or 4.4 

percent of the CD-C project area. 

The Draft EIS was prepared pursuant to the National Environmental Policy Act (NEPA), as well as other 

regulations and statutes, to address possible environmental and socioeconomic impacts that could result 

from implementation of the project. The Draft EIS is not a decision document. Its purpose is to inform the 

public and the decision maker of the impacts associated with implementing the proponent’s proposal, to 

evaluate alternatives to the proposal, and to solicit comments from other agencies and the public. 

Comments are being sought to ensure that the EIS includes an appropriate range of alternatives to the 

Proposed Action and that the analysis of environmental effect is appropriate and complete. 

The CD-C Draft EIS is available for download on the following website: 

http://www.blm.gov/wy/st/en/info/NEPA/documents/rfo/ html 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 iii 
The Draft EIS is also available for review during normal business hours at the following locations: 

 BLM Wyoming State Office, 5353 Yellowstone Road, Cheyenne, Wyoming 

 BLM High Desert District Office, 280 Highway 191 North, Rock Springs, Wyoming 

 BLM Rawlins Field Office, 1300 North Third Street, Rawlins, Wyoming 

 Carbon County Library, 215 West Buffalo Street, Rawlins, Wyoming 

If you wish to submit comments, we request that you make them as specific as possible, with references 

to page numbers and chapters of the document. The most useful comments will contain new technical or 

scientific information, identify data gaps in the impact analysis, and/or provide technical or scientific 

rationale for opinions or preferences. Please refer to “Continental Divide-Creston EIS” in your 

correspondence. Written comments will be accepted by fax, email, or letter for 45 days following the 

publication of the Notice of Availability in the Federal Register by the U.S. Environmental Protection 

Agency. Please provide your comments to: 

Bureau of Land Management 

Attn: David Simons 

Rawlins Field Office 

P.O. Box 2407 (1300 North Third Street) 

Rawlins, WY 82301-2407 

Fax: 307-328-4224 

Email: BLM_WY_Continental_Divide_Creston@blm.gov 

Before including your address, phone number, email address, or other personal identifying information in 

your comment, you should be aware that your entire comment—including your personal identifying 

information—may be made publicly available at any time. While you may ask us in your comment to 

withhold your personal identifying information from public review, we cannot guarantee that we will be 

able to do so. The BLM will not consider anonymous comments. Comments may be published as part of 

the NEPA document and other related documents. All submissions from organizations or businesses will 

be made available for public inspection in their entirety. For further information concerning the 

document, please contact David Simons at (307) 328-4328. 

Sincerely, 

Dennis J. Carpenter 

Rawlins Field Office Manager 

iv Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
TABLE OF CONTENTS 

VOLUME I. 

EXECUTIVE SUMMARY .................................................................................................................... ES-1
 

Purpose and Need for the Action ...................................................................................................... ES-3
 

Scoping and Public Involvement ...................................................................................................... ES-3
 

Proposed Action and Alternatives .................................................................................................... ES-4
 

Affected Environment ...................................................................................................................... ES-6
 

Environmental Impacts: Overview ................................................................................................... ES-7
 

Summary Descriptions: Impacts of the Proposed Action and Alternatives ................................... ES-15
 

1. PURPOSE AND NEED....................................................................................................................1-1
 

1.1 Introduction and Regional Setting .............................................................................................1-1
 

1.2 Overview of the Proposed Project .............................................................................................1-3
 

1.3 Previous and Existing Oil and Gas Development in the Area ...................................................1-4
 

1.4 Purpose and Need for the Action ...............................................................................................1-6
 

1.5 Decisions to be Made ................................................................................................................ 1-6
 

1.6 Regulatory Setting ..................................................................................................................... 1-7
 

1.7 Authorizations and Permits........................................................................................................ 1-7
 

1.8 Conformance with the Rawlins Resource Management Plan ..................................................1-12
 

1.9 Public Participation.................................................................................................................. 1-12
 

1.9.1	 Scoping Process ........................................................................................................1-12
 

1.9.2	 Key Issues and Concerns ..........................................................................................1-13
 

2. THE PROPOSED ACTION AND ALTERNATIVES ...................................................................2-1
 

2.1 Introduction ............................................................................................................................... 2-1
 

2.2 Description of the Proposed Action and Alternatives ...............................................................2-1
 

2.2.1	 The Proposed Action...................................................................................................2-1
 

2.2.2	 Alternative A: 100-Percent Vertical Drilling..............................................................2-6
 

2.2.3	 Alternative B: Enhanced Resource Protection............................................................2-6
 

2.2.4	 Alternative C: Surface Disturbance Cap—High and Low Density
 

Development Areas ...................................................................................................2-18
 

2.2.5	 Alternative D: Directional Drilling ...........................................................................2-21
 

2.2.6	 Alternative E: No Action ..........................................................................................2-21
 

2.3 Alternatives Considered and Eliminated from Detailed Study ................................................2-22
 

2.3.1	 Surface Disturbance Cap with Reclamation Credits and Debits ...............................2-22
 

2.3.2	 Focused Development...............................................................................................2-23
 

2.4 Comparison of Alternatives ..................................................................................................... 2-24
 

3. AFFECTED ENVIRONMENT .........................................................................................................3-1
 

 Physical Environment 

3.1 Geology ..................................................................................................................................... 3-1
 

3.1.1	 Physiography ...............................................................................................................3-1
 

3.1.2	 Regional Geologic Overview......................................................................................3-2
 

3.1.3	 Quaternary Deposits ....................................................................................................3-8
 

3.1.4	 Tertiary—Battle Spring Formation .............................................................................3-9
 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 v 
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3.1.5 Tertiary—Green River Formation ..............................................................................3-9
 

3.1.6 Tertiary—Wasatch Formation ..................................................................................3-10
 

3.1.7 Tertiary—Fort Union Formation ..............................................................................3-11
 

3.1.8 Upper Cretaceous—Lance Formation ......................................................................3-12
 

3.1.9 Geologic Hazards......................................................................................................3-12
 

3.2 Paleontologic Resources .......................................................................................................... 3-13
 

3.2.1 Paleontological Resource Preservation Act ..............................................................3-13
 

3.2.2 Potential Fossil Yield Classification (PFYC) System ...............................................3-14
 

3.2.3 Known Paleontological Resources in the CD-C Project Area ..................................3-15
 

3.2.4 Taphonomy and the Occurrence of Fossils ...............................................................3-16
 

3.3 Soils ......................................................................................................................................... 3-18
 

3.3.1	 General Description of Major Soil Types .................................................................3-19
 

3.3.2	 Soil Limitations .........................................................................................................3-19
 

3.3.3	 Watershed-Based Land Health Assessment ..............................................................3-28
 

3.4 Water Resources ...................................................................................................................... 3-29
 

3.4.1	 Climate and Precipitation ..........................................................................................3-29
 

3.4.2	 Surface Water............................................................................................................3-29
 

3.4.3	 Groundwater .............................................................................................................3-40
 

3.4.4	 Injection Wells ..........................................................................................................3-47
 

3.5 Air Quality............................................................................................................................... 3-49
 

3.5.1 Regional Climate ......................................................................................................3-49
 

3.5.2	 Overview of Regulatory Environment ......................................................................3-51
 

3.5.3	 Air Pollutant Concentrations .....................................................................................3-62
 

3.5.4	 Air Quality Related Values .......................................................................................3-63
 

 Biological Environment 

3.6 Vegetation and Biological Soil Crusts .....................................................................................3-65
 

3.6.1	 Introduction...............................................................................................................3-65
 

3.6.2	 Primary Cover Types ................................................................................................3-67
 

3.6.3	 Watershed-Based Land Health Assessment ..............................................................3-80
 

3.6.4	 Fugitive Dust Effects on Vegetation .........................................................................3-80
 

3.6.5	 Biological Soil Crusts ...............................................................................................3-82
 

3.7 Invasive, Non-native Plant Species .........................................................................................3-83
 

3.8 Wildlife.................................................................................................................................... 3-84
 

3.8.1	 Terrestrial Wildlife ....................................................................................................3-84
 

3.8.2	 Fish..........................................................................................................................3-100
 

3.9 Special Status Species ........................................................................................................... 3-102
 

3.9.1	 Threatened, Endangered, Proposed, or Candidate Species of Wildlife, 

Fish, and Plants .......................................................................................................3-102
 

3.9.2	 BLM Sensitive Species ...........................................................................................3-111
 

3.10 Wild Horses ........................................................................................................................... 3-123
 

 Human Environment 

3.11 Visual Resources ................................................................................................................... 3-127
 

3.11.1	 Visual Resources Characteristics ............................................................................3-127
 

3.11.2	 Visual Resources Management System ..................................................................3-129
 

3.11.3	 Visual Resources Management Class Designations ...............................................3-129
 

3.11.4	 Visual Resource Inventory of February 2011 .........................................................3-130
 

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3.11.5 Visual Resources Management RMP Amendment.................................................3-132
 

3.12 Recreation.............................................................................................................................. 3-132
 

3.12.1	 Recreation Resources..............................................................................................3-132
 

3.12.2	 Recreational Use .....................................................................................................3-134
 

3.12.3	 Recreation Trends ...................................................................................................3-137
 

3.13 Lands with Wilderness Characteristics ..................................................................................3-138
 

3.14 Cultural and Historical Resources .........................................................................................3-139
 

3.14.1 Cultural Chronology of the Area ............................................................................3-139
 

3.14.2 Summary of Extant Cultural Resources ..................................................................3-141
 

3.14.3 Site Types................................................................................................................3-141
 

3.14.4 Summary .................................................................................................................3-144
 

3.15 Socioeconomics ..................................................................................................................... 3-146
 

3.15.1	 Economic Conditions ..............................................................................................3-149
 

3.15.2	 Population and Demographics ................................................................................3-157
 

3.15.3	 Housing...................................................................................................................3-160
 

3.15.4	 Community Infrastructure and Services .................................................................3-164
 

3.15.5	 Local Government Fiscal Conditions .....................................................................3-170
 

3.15.6	 Schools....................................................................................................................3-180
 

3.15.7	 Social Conditions and Trends .................................................................................3-182
 

3.15.8	 Environmental Justice .............................................................................................3-186
 

3.16 Transportation and Access.....................................................................................................3-189
 

3.16.1	 Current Government-Industry Transportation Planning Efforts for the 

Project Area ............................................................................................................3-192
 

3.16.2	 Highway Access to the Project Area .......................................................................3-192
 

3.16.3	 Motor Vehicle Crash Statistics on Highways Providing Access to the 

Project Area ............................................................................................................3-195
 

3.16.4	 County Roads ..........................................................................................................3-196
 

3.16.5	 BLM Roads .............................................................................................................3-198
 

3.16.6	 2007 Drilling and Production Traffic......................................................................3-201
 

3.17 Noise...................................................................................................................................... 3-201
 

 Management Environment 

3.18 Range Resources.................................................................................................................... 3-203
 

3.18.1	 Introduction.............................................................................................................3-203
 

3.18.2	 Existing Allotment Disturbance ..............................................................................3-207
 

3.19 Oil and Gas and other Minerals .............................................................................................3-209
 

3.19.1	 Locatable Minerals..................................................................................................3-210
 

3.19.2	 Leasable Minerals ...................................................................................................3-210
 

3.19.3	 Mineral Materials....................................................................................................3-214
 

3.20 Health and Safety................................................................................................................... 3-217
 

3.20.1 Worker Safety .........................................................................................................3-217
 

3.20.2	 Public Health and Safety.........................................................................................3-217
 

3.20.3	 Other Risks and Hazards.........................................................................................3-218
 

3.21 Waste and Hazardous Materials Management.......................................................................3-218
 

3.21.1 Waste Management .................................................................................................3-218
 

3.21.2 Hazardous Materials Management ..........................................................................3-219
 

3.21.3 Hazardous Materials Releases and Spill Response .................................................3-220
 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 vii 
TABLE OF CONTENTS 

4. ENVIRONMENTAL CONSEQUENCES .......................................................................................4-1
 

4.0.1 Introduction.................................................................................................................4-1
 

4.0.2 Historic and Future Impacts ........................................................................................4-2
 

4.0.3 Distribution and Density of Future Impacts ................................................................4-7
 

 Physical Environment 

4.1 Geology ................................................................................................................................... 4-10
 

4.1.1 Introduction...............................................................................................................4-10
 

4.1.2 Management Objectives and Impact Significance Criteria .......................................4-10
 

4.1.3 Direct and Indirect Impacts .......................................................................................4-10
 

4.1.4 Impact Summary.......................................................................................................4-11
 

4.1.5 Unavoidable Adverse Impacts and Additional Mitigation Measures .......................4-11
 

4.2 Paleontologic Resources .......................................................................................................... 4-11
 

4.2.1 Management Objectives and Impact Significance Criteria .......................................4-11
 

4.2.2 Direct and Indirect Impacts .......................................................................................4-11
 

4.2.3 Impact Summary.......................................................................................................4-12
 

4.2.4 Unavoidable Adverse Impacts and Additional Mitigation Measures .......................4-13
 

4.3 Soils ......................................................................................................................................... 4-13
 

4.3.1 Introduction...............................................................................................................4-13
 

4.3.2 Management Objectives and Impact Significance Criteria .......................................4-13
 

4.3.3 Direct and Indirect Impacts .......................................................................................4-13
 

4.4 Water Resources ...................................................................................................................... 4-20
 

4.4.1 Introduction...............................................................................................................4-20
 

4.4.2 Assumptions for Analysis.........................................................................................4-21
 

4.4.3 Management Objectives and Impact Significance Criteria .......................................4-22
 

4.4.4 Direct and Indirect Impacts .......................................................................................4-23
 

4.4.5 Summary of Impacts .................................................................................................4-36
 

4.4.6 Unavoidable Adverse Impacts and Additional Mitigation Measures .......................4-38
 

4.5 Air Quality............................................................................................................................... 4-39
 

4.5.1 Introduction...............................................................................................................4-39
 

4.5.2 Management Objectives and Impact Significance Criteria .......................................4-41
 

4.5.3 Emission Inventory Development .............................................................................4-41
 

4.5.4 Greenhouse Gases.....................................................................................................4-44
 

4.5.5 Regional Emission Inventory Development .............................................................4-45
 

4.5.6 Air Quality Modeling ................................................................................................4-46
 

4.5.7 Direct and Indirect Impacts .......................................................................................4-48
 

4.5.8 Impact Summary.......................................................................................................4-69
 

4.5.9 Unavoidable Adverse Impacts and Additional Mitigation Measures .......................4-70
 

 Biological Environment 

4.6 Vegetation................................................................................................................................ 4-71
 

4.6.1 Introduction...............................................................................................................4-71
 

4.6.2 Management Objectives and Impact Significance Criteria .......................................4-71
 

4.6.3 Direct and Indirect Impacts .......................................................................................4-72
 

4.6.4 Impact Summary.......................................................................................................4-75
 

4.6.5 Unavoidable Adverse Impacts and Additional Mitigation Measures .......................4-76
 

4.7 Invasive, Non-native Plant Species .........................................................................................4-76
 

4.7.1 Introduction...............................................................................................................4-76
 

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4.7.2 Management Objectives and Impact Significance Criteria .......................................4-77
 

4.7.3 Direct and Indirect Impacts .......................................................................................4-77
 

4.7.4 Impact Summary.......................................................................................................4-80
 

4.7.5 Unavoidable Adverse Impacts and Additional Mitigation Measures .......................4-80
 

4.8 Wildlife.................................................................................................................................... 4-81
 

4.8.1 Introduction...............................................................................................................4-81
 

4.8.2 Management Objectives and Impact Significance Criteria .......................................4-81
 

4.8.3 Direct and Indirect Impacts .......................................................................................4-82
 

4.8.4 Impact Summary.......................................................................................................4-97
 

4.8.5 Unavoidable Adverse Impacts and Additional Mitigation Measures .......................4-98
 

4.9 Special Status Species ............................................................................................................. 4-99
 

4.9.1 Introduction...............................................................................................................4-99
 

4.9.2 Management Objectives and Impact Significance Criteria .......................................4-99
 

4.9.3 Direct and Indirect Impacts .....................................................................................4-100
 

4.9.4 Impact Summary.....................................................................................................4-119
 

4.9.5 Unavoidable Adverse Impacts and Additional Mitigation Measures .....................4-120
 

4.10 Wild Horses ........................................................................................................................... 4-121
 

4.10.1 Introduction.............................................................................................................4-121
 

4.10.2 Management Objectives and Impact Significance Criteria .....................................4-122
 

4.10.3 Direct and Indirect Impacts .....................................................................................4-122
 

4.10.4 Impacts Summary ...................................................................................................4-125
 

4.10.5 Unavoidable Adverse Impacts and Additional Mitigation Measures .....................4-125
 

 Human Environment 

4.11 Visual Resources ................................................................................................................... 4-126
 

4.11.1 Introduction.............................................................................................................4-126
 

4.11.2 Management Objectives and Impact Significance Criteria .....................................4-126
 

4.11.3 Direct and Indirect Impacts .....................................................................................4-127
 

4.11.4 Impact Summary.....................................................................................................4-131
 

4.11.5 Unavoidable Adverse Impacts and Additional Mitigation Measures .....................4-131
 

4.11.6 Effect of the VRM Amendment to the Resource Management Plan ......................4-132
 

4.12 Recreation.............................................................................................................................. 4-132
 

4.12.1 Introduction.............................................................................................................4-132
 

4.12.2 Management Objectives and Impact Significance Criteria .....................................4-132
 

4.12.3 Direct and Indirect Impacts .....................................................................................4-133
 

4.12.4 Impact Summary.....................................................................................................4-136
 

4.12.5 Unavoidable Adverse Impacts and Additional Mitigation Measures .....................4-136
 

4.13 Lands with Wilderness Characteristics ..................................................................................4-136
 

4.14 Cultural and Historical Resources .........................................................................................4-137
 

4.14.1 Introduction.............................................................................................................4-137
 

4.14.2 Management Objectives and Impact Significance Criteria .....................................4-137
 

4.14.3 Direct and Indirect impacts .....................................................................................4-139
 

4.14.5 Impact Summary.....................................................................................................4-141
 

4.14.6 Unavoidable Adverse Impacts and Additional Mitigation Measures .....................4-141
 

4.15 Socioeconomics ..................................................................................................................... 4-142
 

4.15.1 Planning Documents and Regulations ....................................................................4-142
 

4.15.2 Direct and Indirect Impacts .....................................................................................4-145
 

4.15.3 Impact Summary.....................................................................................................4-186
 

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TABLE OF CONTENTS 

4.15.4	 Unavoidable Adverse Impacts and Additional Mitigation Measures .....................4-189
 

4.16 Transportation........................................................................................................................ 4-189
 

4.16.1	 Planning Documents and Criteria ...........................................................................4-189
 

4.16.2	 Direct and Indirect Impacts .....................................................................................4-190
 

4.16.3	 Impact Summary.....................................................................................................4-202
 

4.16.4	 Unavoidable Adverse Impacts and Additional Mitigation Measures .....................4-203
 

4.17 Noise...................................................................................................................................... 4-204
 

4.17.1	 Introduction.............................................................................................................4-204
 

4.17.2	 Management Objectives and Impact Significance Criteria .....................................4-204
 

4.17.3	 Direct and Indirect Impacts .....................................................................................4-205
 

4.17.4	 Impact Summary.....................................................................................................4-209
 

4.17.5	 Unavoidable Adverse Impacts and Additional Mitigation Measures .....................4-209
 

 Management Environment 

4.18 Range Resources.................................................................................................................... 4-211
 

4.18.1	 Introduction.............................................................................................................4-211
 

4.18.2	 Management Objectives and Impact Significance Criteria .....................................4-211
 

4.18.3	 Direct and Indirect Impacts .....................................................................................4-211
 

4.18.4	 Impact Summary.....................................................................................................4-216
 

4.18.5	 Unavoidable Adverse Impacts and Additional Mitigation Measures .....................4-217
 

4.19 Oil and Gas and Other Minerals ............................................................................................4-218
 

4.19.1	 Introduction.............................................................................................................4-218
 

4.19.2	 Management Objectives and Impact Significance Criteria .....................................4-218
 

4.19.3	 Direct and Indirect Impacts .....................................................................................4-218
 

4.19.4	 Impact Summary.....................................................................................................4-219
 

4.19.5	 Unavoidable Adverse Impacts and Additional Mitigation Measures .....................4-219
 

4.20 Health and Safety................................................................................................................... 4-219
 

4.20.1	 Introduction.............................................................................................................4-219
 

4.20.2	 Management Objectives and Impact Significance Criteria .....................................4-219
 

4.20.3	 Direct and Indirect Impacts .....................................................................................4-220
 

4.20.4	 Impact Summary.....................................................................................................4-222
 

4.20.5	 Unavoidable Adverse Impacts and Additional Mitigation Measures .....................4-222
 

4.21 Waste and Hazardous Materials ............................................................................................4-223
 

4.21.1	 Management Objectives and Impact Significance Criteria .....................................4-223
 

4.21.2	 Direct and Indirect Impacts .....................................................................................4-223
 

4.21.3	 Impact Summary.....................................................................................................4-227
 

4.21.4	 Unavoidable Adverse Impacts and Additional Mitigation Measures .....................4-227
 

5. CUMULATIVE IMPACTS................................................................................................................5-1
 

 Physical Environment.............................................................................................................5-6
 

5.1 Geology ..................................................................................................................................... 5-6
 

5.2 Paleontologic Resources ............................................................................................................ 5-6
 

5.3 Soils ........................................................................................................................................... 5-6
 

5.4 Water Resources ........................................................................................................................ 5-7
 

5.4.1	 Cumulative Impacts Common to the CD-C Project-Specific and 

Watershed Analysis Areas ..........................................................................................5-7
 

5.4.2	 Cumulative Impacts within the CD-C Project Area ....................................................5-9
 

5.4.3	 Cumulative Impacts within the Watershed Area ........................................................5-9
 

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TABLE OF CONTENTS
 

5.5 Air Quality............................................................................................................................... 5-11
 

5.5.1 Emissions from Regional Sources ............................................................................5-11
 

5.5.2 Criteria Pollutants Impacts ........................................................................................5-16
 

5.3.3 Visibility Impacts......................................................................................................5-17
 

5.3.4 Atmospheric Deposition Impacts ..............................................................................5-18
 

5.3.5 Climate Change Impacts ...........................................................................................5-19
 

 Biological Environment 

5.6 Vegetation and Riparian/Wetland Communities .....................................................................5-20
 

5.7 Invasive, Non-native Species...................................................................................................5-20
 

5.8 Wildlife.................................................................................................................................... 5-21
 

5.8.1 Big Game ..................................................................................................................5-21
 

5.8.2 Raptors ......................................................................................................................5-26
 

5.8.3 Fish............................................................................................................................ 5-26
 

5.9 Special Status Plant, Wildlife, and Fish Species .....................................................................5-28
 

5.9.1 Threatened, Endangered, Proposed or Candidate Wildlife Species ..........................5-28
 

5.9.2 Threatened and Endangered Fish Species.................................................................5-32
 

5.9.3 Threatened and Endangered Plant Species ...............................................................5-32
 

5.9.4 Sensitive Wildlife Species ........................................................................................5-33
 

5.9.5 Sensitive Plant Species .............................................................................................5-34
 

5.10 Wild Horses ............................................................................................................................. 5-34
 

 Human Environment 

5.11 Visual Resources ..................................................................................................................... 5-35
 

5.12 Recreation................................................................................................................................ 5-37
 

5.13 Lands with Wilderness Characteristics ....................................................................................5-38
 

5.14 Cultural and Historical Resources ...........................................................................................5-38
 

5.15 Socioeconomics ....................................................................................................................... 5-40
 

5.16 Transportation.......................................................................................................................... 5-43
 

5.17 Noise........................................................................................................................................ 5-44
 

 Management Environment 

5.18 Range Resources...................................................................................................................... 5-45
 

5.19 Oil and Gas and Other Minerals ..............................................................................................5-45
 

5.20 Health and Safety..................................................................................................................... 5-45
 

5.21 Waste and Hazardous Materials Management.........................................................................5-46
 

6. CONSULTATION AND COORDINATION ...................................................................................6-1
 

6.1 Introduction ............................................................................................................................... 6-1
 

6.2 Public Participation.................................................................................................................... 6-1
 

6.3 List of Preparers......................................................................................................................... 6-4
 

7. REFERENCES .................................................................................................................................. 7-1
 

8. GLOSSARY ....................................................................................................................................... 8-1
 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 xi 
TABLE OF CONTENTS 

LIST OF TABLES 

Table ES-1. CD-C surface disturbance – Historical, Proposed Action and Alternatives 

(acres) ........................................................................................................................... ES-8
 

Table ES-2. Comparison of impacts by alternative .......................................................................... ES-9
 

Table 1-1. Estimated surface and mineral ownership in the CD-C project area ...............................1-3
 

Table 1-2. Oil and gas development in and near the CD-C project area ...........................................1-4
 

Table 1-3. Federal, state, and county authorizing actions .................................................................1-9
 

Table 2.4-1. CD-C project area disturbance: Proposed Action and alternatives (acres) ....................2-24
 

Table 2.4-2. Comparison of impacts by alternative ...........................................................................2-25
 

Table 3.1-1. Important natural landmarks in the CD-C project area (north to south) ..........................3-1
 

Table 3.1-2. Surface and subsurface geologic deposits in the CD-C project area ...............................3-3
 

Table 3.3-1. Potential soil limitations in the CD-C project area ........................................................3-20
 

Table 3.3-2. Water erosion classes determined by Erosion Factor (K) and Slope in the 

CD-C project area ..........................................................................................................3-21
 

Table 3.4-1. Surface-water quality at selected sites associated with the CD-C project area ..............3-37
 

Table 3.4-2. Groundwater quality parameters for selected aquifers associated with the 

CD-C project area ..........................................................................................................3-45
 

Table 3.5-1. Mean Monthly Temperature Ranges and Total Precipitation Amounts ........................3-49
 

Table 3.5-2. Wind Speed Distribution, Wamsutter, Wyoming, 2008–2010 ......................................3-51
 

Table 3.5-3. Wind Direction Frequency Distribution, Wamsutter, Wyoming, 2008–2010 ...............3-51
 

Table 3.5-4. Ambient air quality standards and PSD increments (μg m3

) .........................................3-54
 

Table 3.5-5. Acute RELs (1-hour exposure) ......................................................................................3-55
 

Table 3.5-6. Non-Carcinogenic HAP RfCs (annual average)1

 ...........................................................3-55
 

Table 3.5-7. PSD increments (μg/m3

) ................................................................................................3-56
 

Table 3.5-8. Background ambient air quality concentrations (μg/m3

) ...............................................3-63
 

Table 3.5-9. Background nitrogen and sulfur deposition values (kg/ha-yr).......................................3-64
 

Table 3.5-10. Background ANC values for acid-sensitive lakes ..........................................................3-64
 

Table 3.6-1. Primary cover types within the project area ..................................................................3-67
 

Table 3.8-1. Big game Herd Unit population parameters within the CD-C project area ...................3-85
 

Table 3.8-2. Big game seasonal ranges (acres) within the project area .............................................3-86
 

Table 3.8-3. Pronghorn Crucial Winter Range condition assessment results, 2007, 2008, 

and 2010......................................................................................................................... 3-89
 

Table 3.8-4. Mule deer Crucial Winter Range condition assessment results, 2007, 2008, 

and 2010......................................................................................................................... 3-92
 

Table 3.8-5. Occurrence potential and documented nest sites of raptor and vulture species
 

within the CD-C project area .........................................................................................3-98
 

Table 3.8-6. Fish species observed within, or that may potentially occur immediately
 

upstream or downstream of, the CD-C project area .....................................................3-101
 

Table 3.9-1. Occurrence potential of Threatened, Endangered, Proposed, and Candidate 

species within or near the CD-C project area ..............................................................3-102
 

Table 3.9-2. Greater sage-grouse harvest numbers for the South Central Conservation 

Area.............................................................................................................................. 3-108
 

Table 3.9-3. Occurrence potential and habitat associations of BLM Sensitive Species 

within or near the CD-C project area ...........................................................................3-111
 

Table 3.10-1. Commonly used Animal Unit Equivalents ..................................................................3-126
 

Table 3.11-1. Total and BLM-administered land area in the project area by VRM Class .................3-130
 

Table 3.12-1. Indicators of hunting activity by species in WGFD Hunt Areas that include 

the CD-C project area, 2009 ........................................................................................3-135
 

xii Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
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Table 3.12-2. Number of active hunters by species in WGFD Hunt Areas that include the 

CD-C project area, 2002–2009 ....................................................................................3-137
 

Table 3.14-1. Prehistoric chronology of the Wyoming Basin............................................................3-139
 

Table 3.14-2. Historic chronology of the Great Divide Basin and the Washakie Basin ....................3-141
 

Table 3.15-1. Full-time and part-time covered employment, by industrial sector, 2009 ...................3-150
 

Table 3.15-2. Population of selected Carbon and Sweetwater County communities: 2000–
 

2010 ............................................................................................................................. 3-159
 

Table 3.15-3. 2010 Census housing status by county and community ..............................................3-161
 

Table 3.15-4. Rock Springs total housing units by housing type: January 2007 ...............................3-163
 

Table 3.15-5. Annual sales, use, and lodging taxes generated by sales in Carbon County, 

by levy ......................................................................................................................... 3-172
 

Table 3.15-6. Annual sales, use and lodging tax generated by sales in Sweetwater County,
 

by levy ......................................................................................................................... 3-173
 

Table 3.15-7. Annual sales and use tax collections by the mining industry in Carbon and
 

Sweetwater Counties, 2006–2010................................................................................3-173
 

Table 3.15-8. General fund revenues and expenditures, Carbon County...........................................3-174
 

Table 3.15-9. General fund revenues and expenditures, Sweetwater County (in millions)...............3-175
 

Table 3.15-10. Total assessed value, affected cities and towns ...........................................................3-176
 

Table 3.15-11. Total annual sales and use tax distributions, cities and towns.....................................3-176
 

Table 3.15-12. General fund revenue and expenditures, City of Rawlins ...........................................3-178
 

Table 3.15-13. General fund revenue and expenditures, City of Rock Springs...................................3-179
 

Table 3.15-14. Revenue and expenditures, City of Green River..........................................................3-179
 

Table 3.15-15. School district revenue, staffing, and enrollment, 2009 .............................................3-181
 

Table 3.15-16. Percentage of minorities in the State of Wyoming, Carbon County, 

Sweetwater County, the CD-C project area, and selected communities ......................3-188
 

Table 3.15-17. Poverty levels in the United States, State of Wyoming, Carbon County, and 

Sweetwater County, 2000 and 2009 ............................................................................3-189
 

Table 3.16-1. AADT on highways providing access to the CD-C project area: 1999, 2009, 

2020, and 2030................................................................................................................ 194
 

Table 3.17-1. Typical noise measurements from common energy development-related 

sources in the CD-C project area .................................................................................3-202
 

Table 3.18-1. Estimated allotment acreage and AUMs within the CD-C project area ......................3-205
 

Table 3.18-2. Historic surface disturbance by allotment, initial and long-term .................................3-208
 

Table 3.19-1. Oil and gas fields in the CD-C project area and cumulative production as of 

2007 ............................................................................................................................. 3-213
 

Table 4.0-1. CD-C surface disturbance – historic, Proposed Action and Alternatives 

(acres) .............................................................................................................................. 4-5
 

Table 4.0-2. CD-C estimated well pad numbers by alternative ...........................................................4-6
 

Table 4.3-1. Distribution of potential soil limitations based on current well locations 

within the CD-C project area .........................................................................................4-16
 

Table 4.4-1. The potential for Significant (S) or Not Significant (NS) impacts for surface 

water and groundwater significance criteria. .................................................................4-37
 

Table 4.5-1. Modeled CD-C project emissions control measures ......................................................4-43
 

Table 4.5-2. CD-C project alternative emission summary (tpy)........................................................4-44
 

Table 4.5-3. CD-C project alternative GHG emission summary (metric tpy) ...................................4-45
 

Table 4.5-4a. Production sources, criteria pollutant modeling results: 100-meter receptor 

distance, Proposed Action..............................................................................................4-50
 

Table 4.5-4b. Production sources, criteria pollutant modeling results: 250-meter receptor 

distance, Proposed Action..............................................................................................4-50
 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 xiii 
TABLE OF CONTENTS 

Table 4.5-5a. Field development sources, criteria pollutant modeling results: 100-meter 

receptor distance, Proposed Action................................................................................4-51
 

Table 4.5-5b. Field development sources, criteria pollutant modeling results: 250-meter 

receptor distance, Proposed Action................................................................................4-52
 

Table 4.5-6a. Production sources, maximum long-term (1-hour) HAP modeling results: 

100-meter receptor distance, Proposed Action ..............................................................4-52
 

Table 4.5-6b. Production sources, maximum long-term (1-hour) HAP modeling results: 

250-meter receptor distance, Proposed Action ..............................................................4-53
 

Table 4.5-7a. Production sources, maximum long-term (annual) HAP modeling results: 

100-meter receptor distance, Proposed Action ..............................................................4-53
 

Table 4.5-7b. Production sources, maximum long-term (annual) HAP modeling results: 

250-meter receptor distance, Proposed Action ..............................................................4-53
 

Table 4.5-8. Long-term modeled formaldehyde MLE and MEI cancer risk analyses for 

proposed compression and gas plant, Proposed Action .................................................4-54
 

Table 4.5-9. Long-term modeled MLE and MEI cancer risk analyses for production well 

case: 16 wells, 1 multi-well pad, Proposed Action ........................................................4-55
 

Table 4.5-10. Mid-Field criteria pollutant modeling results, Proposed Action ....................................4-56
 

Table 4.5-11. Visibility impacts using FLAG 2010 screening method, Proposed Action ...................4-57
 

Table 4.5-12a. Production sources, criteria pollutant modeling results: 100-meter receptor 

distance, Alternative A ..................................................................................................4-58
 

Table 4.5-12b. Production sources, criteria pollutant modeling results: 250-meter receptor 

distance, Alternative A ..................................................................................................4-59
 

Table 4.5-13a. Field development sources, criteria pollutant modeling results: 100-meter 

receptor distance, Alternative A ....................................................................................4-60
 

Table 4.5-13b. Field development sources, criteria pollutant modeling results: 250-meter 

receptor distance, Alternative A ....................................................................................4-61
 

Table 4.5-14a. Field development sources, criteria pollutant modeling results: 100-meter 

receptor distance, Alternative D ....................................................................................4-65
 

Table 4.5-14b. Field development sources, criteria pollutant modeling results: 250-meter 

receptor distance, Alternative D ....................................................................................4-66
 

Table 4.5-15. Mid-Field criteria pollutant modeling results, Alternative E .........................................4-68
 

Table 4.8-1. Affected pronghorn Crucial Winter Range, new and existing surface 

disturbance ..................................................................................................................... 4-84
 

Table 4.8-2. Affected mule deer Crucial Winter Range, new and existing surface 

disturbance ..................................................................................................................... 4-86
 

Table 4.11-1. Roads accessing VRM Class III in the CD-C project area where users would 

likely see oil and gas facilities under the action alternatives .......................................4-129
 

Table 4.15-1. Overview of direct onsite labor effort to implement the Proposed Action, 

CD-C project area ........................................................................................................4-152
 

Table 4.15-2. Average onsite and total direct employment during the development phase, 

Proposed Action...........................................................................................................4-153
 

Table 4.15-3 Incremental direct employment during field operations and production, 

Proposed Action...........................................................................................................4-154
 

Table 4.15-4. Incremental numbers of jobs by industrial sector, Year 13 .........................................4-156
 

Table 4.15-5. Summary of incremental population impacts from the Proposed Action ....................4-159
 

Table 4.15-6. Incremental resident population and non-resident workers by community .................4-161
 

Table 4.15-7. Proposed Action-related temporary and long-term housing demand ..........................4-163
 

Table 4.15-8. Projected Proposed Action-related school enrollment: Years 1 through 20 ................4-167
 

xiv Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
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Table 4.15-9. Projected state severance tax revenues and initial allocations, Proposed 

Action ($2010).............................................................................................................4-170
 

Table 4.15-10. Projected federal mineral royalties and distribution ($2010).......................................4-171
 

Table 4.15-11. Projected allocation of Wyoming’s share of federal mineral royalties, 

Proposed Action ($2010) .............................................................................................4-172
 

Table 4.15-12. Projected gross products and ad valorem taxes to local counties and school 

districts, Proposed Action ($2008) ..............................................................................4-173
 

Table 4.15-13. Projected public-sector taxes and royalties on gas and condensate 

production, Proposed Action ($2010)..........................................................................4-175
 

Table 4.15-14. Incremental resident population impacts from Alternative A ......................................4-178
 

Table 4.15-15. Summary of projected public-sector taxes and royalties on gas and 

condensate production, Alternative A ($2010)............................................................4-179
 

Table 4.15-16. Summary of projected taxes and public-sector royalties on gas and 

condensate production, No Action ($2010) .................................................................4-186
 

Table 4.16-1. Per-well round-trip estimates: drilling and completion ...............................................4-191
 

Table 4.16-2. Estimated production traffic (round-trips)...................................................................4-191
 

Table 4.16-3. Projected AADT, highways providing access to the CD-C project area: Year 

1, Proposed Action.......................................................................................................4-194
 

Table 4.16-4. Projected AADT, highways providing access to the CD-C project area: Year 

10, Proposed Action .....................................................................................................4-195
 

Table 4.16-5. Projected AADT, highways providing access to the CD-C project area: Year 

20, Proposed Action .....................................................................................................4-196
 

Table 4.16-6. Projected traffic effects on highways associated with ancillary facilities: 

Proposed Action...........................................................................................................4-197
 

Table 4.17-1. Typical noise measurements from common energy development-related 

sources in the CD-C project area .................................................................................4-206
 

Table 5.0-1. Ongoing and Reasonably Foreseeable Future Actions ....................................................5-3
 

Table 5.5-1. RFD emissions within the study area. ............................................................................5-12
 

Table 5.5-2. Regional emissions summary table for the 2022 future year (tpy)................................5-13
 

Table 5.5-3. Regional 2022-2008 emissions difference summary table (tpy) ...................................5-15
 

Table 5.5-4. CD-C project and regional sources: mid-field criteria pollutant modeling 

results............................................................................................................................. 5-17
 

Table 5.5-5. Cumulative visibility results ..........................................................................................5-18
 

Table 5.5-6. Cumulative nitrogen and sulfur deposition impacts ......................................................5-18
 

Table 5.5-7. 2022-2008 Change in cumulative nitrogen and sulfur deposition .................................5-19
 

Table 5.14-1. Historic trails and roads in the CD-C project area .........................................................5-39
 

Table 6.3-1. Rawlins Field Office Interdisciplinary Team...................................................................6-4
 

Table 6.3-2. Consultant Interdisciplinary Team ...................................................................................6-5
 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 xv 
TABLE OF CONTENTS 

LIST OF MAPS
 

Map ES-1. Project boundary and existing natural gas development (EIS Map 1-1) ...................... ES-2
 

Map 1-1. Project boundary and existing natural gas development ..................................................1-2
 

Map 1-2. Oil and gas development in and near the CD-C project area ...........................................1-5
 

Map 2-1. High-density and low-density natural gas development areas, CD-C project 

area................................................................................................................................. 2-20
 

Map 3.3-1. Water-erosion potential for the CD-C project area ........................................................3-22
 

Map 3.3-2. Wind-erosion potential for the CD-C project area .........................................................3-23
 

Map 3.3-3. Runoff potential in the CD-C project area .....................................................................3-25
 

Map 3.3-4. Potential road construction limitations in the CD-C project area ..................................3-26
 

Map 3.3-5. Reclamation potential for soils in the CD-C project area ..............................................3-27
 

Map 3.4-1. CD-C project area with watershed basins and streams ..................................................3-30
 

Map 3.4-2. CD-C project area surface water features ......................................................................3-32
 

Map 3.5-1. Air quality monitoring stations within the CD-C study area .........................................3-53
 

Map 3.5-2. The concentrated development area (from WDEQ-AQD, 2010) ..................................3-60
 

Map 3.6-1. General location of Level IV Ecoregions within the CD-C project area .......................3-66
 

Map 3.6-2. Major land cover types within the CD-C project area ...................................................3-68
 

Map 3.8-1. Pronghorn Herd Units in and around the CD-C project area .........................................3-87
 

Map 3.8-2. Pronghorn seasonal ranges and migratory movements in and around the CDC project area ................................................................................................................. 3-88
 

Map 3.8-3. Mule Deer Herd Units in and around the CD-C project area .........................................3-90
 

Map 3.8-4. Mule deer seasonal ranges and migratory movements in and around the CDC project area ................................................................................................................. 3-91
 

Map 3.8-5. Elk Herd Units in and around the CD-C project area ....................................................3-94
 

Map 3.8-6. Elk seasonal ranges and migratory movements in and around the CD-C 

project area..................................................................................................................... 3-95
 

Map 3.8-7. Big game Crucial Winter Ranges in the CD-C project area ..........................................3-96
 

Map 3.8-8. Raptor nest site locations in or within one mile of the CD-C project area ....................3-99
 

Map 3.9-1. Black-footed ferret Non-Block Clearance areas and 2007 prairie-dog colony
 

mapping area in and around the CD-C project area.....................................................3-104
 

Map 3.9-2. Greater sage-grouse potential nesting/brood-rearing habitat, leks, core areas, 

and 11-mile CD-C project area buffer .........................................................................3-107
 

Map 3.9-3a. White-tailed prairie-dog colonies within the CD-C project area .................................3-114
 

Map 3.9-3b. White-tailed prairie-dog colonies within the CD-C project area .................................3-115
 

Map 3.9-4. Occupied and potential mountain plover habitat within the CD-C project 

area............................................................................................................................... 3-118
 

Map 3.9-5. Lower Muddy Creek Watershed..................................................................................3-121
 

Map 3.10-1. Wild horse management areas within the CD-C project area in relation to 

major land cover types and affected grazing allotments ..............................................3-124
 

Map 3.11-1. Current VRM Classification of land within the CD-C project area with 

comparison to existing well development ....................................................................3-131
 

Map 3.12-1. Recreation in the CD-C project area............................................................................3-136
 

Map 3.15-1. CD-C project area and surrounding area .....................................................................3-148
 

Map 3.16-1. Highway and county road access to and within the CD-C project area .......................3-191
 

Map 3.16-2. BLM roads within the CD-C project area ....................................................................3-199
 

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Map 3.18-1. Affected grazing allotments in the CD-C project area in relation to major 

land cover types ...........................................................................................................3-204
 

Map 3.19-1. Permitted sand, gravel, and scoria/klinker mines within and near the CD-C 

project area................................................................................................................... 3-216
 

Map 4.0-1. Past surface disturbance, by section, within the CD-C project area ................................4-4
 

Map 4.0-2. Current well spacing orders in the CD-C project area .....................................................4-9
 

Map 4.5-1. Study area showing 36/12/4 kilometer (km) nested modeling grid used for 

photochemical grid modeling (left panel) and expanded view of the 4-km 

domain that was the focus of the far-field modeling impact analysis showing 

boundary of CD-C project area (yellow) and nearby Class I/sensitive Class 

II areas............................................................................................................................ 4-45
 

Map 5.0-1. Reasonably foreseeable future actions in the cumulative impact analysis area ...............5-5
 

Map 5.8-1. Cumulative impact analysis area, pronghorn .................................................................5-23
 

Map 5.8-2. Cumulative impact analysis area, mule deer ..................................................................5-25
 

Map 5.8-3. Cumulative impact analysis area, raptors ......................................................................5-27
 

Map 5.9-1. Cumulative impact analysis area, black-footed ferret ....................................................5-29
 

Map 5.9-2. Cumulative impact analysis area, greater sage-grouse ..................................................5-31
 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 xvii 
TABLE OF CONTENTS 

LIST OF FIGURES 

Figure 3.1-1. Generalized stratigraphic column.................................................................................3-6
 

Figure 3.1-2. Eocene stratigraphic units, Greater Green River Basin ................................................3-7
 

Figure 3.5-1. Wamsutter, WY meteorological data wind rose .........................................................3-50
 

Figure 3.9-1. Average peak observed male attendance for leks associated with the 

project area (WGFD 2011).......................................................................................3-109
 

Figure 3.15-1. Producing oil and gas wells in Carbon and Sweetwater Counties, 2000–
 

2010..........................................................................................................................3-146
 

Figure 3.15-2. Total full-time and part-time employment, 1970–2009 ...........................................3-149
 

Figure 3.15-3. Local resident labor force: 1990–2010 .....................................................................3-151
 

Figure 3.15-4. Local Unemployment Rates (average annual): 1990–2010 ......................................3-152
 

Figure 3.15-5. Population, Carbon and Sweetwater Counties: 1970–2010 .....................................3-158
 

Figure 3.15-6. Total assessed value, Carbon and Sweetwater Counties, 2000–2010 ......................3-171
 

Figure 3.15-7. Annual sales and use tax distributions to Carbon and Sweetwater 

Counties, fiscal years 2004–2010 .............................................................................3-172
 

Figure 3.15-8. General fund revenues for Carbon and Sweetwater Counties, 2004–2010 ..............3-175
 

Figure 3.15-9. Fall enrollment, Carbon County School District #1 and Sweetwater 

County School Districts #1 and #2, 1991–2010 .......................................................3-180
 

Figure 3.16-1. Annual number of crashes on I-80 between Rawlins and Rock Springs: 

1998–2010 ................................................................................................................3-195
 

Figure 3.16-2. Annual number of crashes on WY 789 between Creston Junction and 

Baggs and on US 287 between Rawlins and Lamont: 1998–2010 ...........................3-196
 

Figure 4.5-1. The Concentrated Development Area (CDA) ............................................................4-42
 

Figure 4.9-1. Relative abundance of two length groups of three species within the upper 

Muddy Creek watershed as a function of the prevalence of rock substrates 

at the reach scale from Bower (2005). Plots were generated using the 

averaged multi-model linear-regression function for both length groups of 

the three species........................................................................................................4-107
 

Figure 4.9-2. Relative abundance of two length groups of three species within the upper 

Muddy Creek watershed as a function of maximum channel unit depth 

from Bower (2005). Plots were generated using the averaged multi-model 

linear-regression function for both length groups of the three species 

above minimum depth thresholds............................................................................. 4-107
 

Figure 4.9-3. Example of erosion resulting from concentration of surface runoff at 

drainage crossings ....................................................................................................4-108
 

Figure 4.11.1. Example of existing site in the project area ..............................................................4-127
 

Figure 4.15-1. Number of new wells drilled in the project area, Proposed Action ..........................4-150
 

Figure 4.15-2. Estimated incremental annual gas production, Proposed Action .............................4-150
 

Figure 4.15-3. Direct employment, onsite and off-site, Proposed Action ........................................4-154
 

Figure 4.15-4. Incremental direct employment, Proposed Action ...................................................4-155
 

Figure 4.15-5. Direct, indirect, and induced employment effects from the Proposed 

Action in Sweetwater and Carbon Counties .............................................................4-156
 

Figure 4.15-6. Total employment effects in Sweetwater and Carbon Counties from the 

Proposed Action .......................................................................................................4-157
 

Figure 4.15-7. Projected net migration into the study area ..............................................................4-159
 

Figure 4.15-8. Forecast population increments due to the Proposed Action ....................................4-160
 

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TABLE OF CONTENTS
 

Figure 4.15-9. Increases in school-age children due to the Proposed Action ..................................4-168
 

Figure 4.15-10. Projected value, annual natural gas and liquid condensate production, 

Proposed Action .......................................................................................................4-170
 

Figure 4.15-11. Distribution of public-sector taxes and royalties, Proposed Action .........................4-175
 

Figure 4.15-12. Total incremental employment, Alternative A compared with the 

Proposed Action .......................................................................................................4-178
 

Figure 4.15-13. Projected annual natural gas production (MMcf), Alternative D and 

Proposed Action .......................................................................................................4-182
 

Figure 4.15-14. Projected annual natural gas production under the No Action Alternative ..............4-183
 

Figure 4.15-15. Incremental employment in Sweetwater and Carbon Counties, No Action 

and Proposed Action.................................................................................................4-184
 

Figure 4.15-16. Incremental population change, No Action and Proposed Action ...........................4-184
 

Figure 4.15-17. Projected annual value of gas and condensate production, No Action .....................4-185
 

Figure 4.16-1. Drilling/field development AADT, Proposed Action ...............................................4-193
 

Figure 4.16-2. Total project-related AADT: Alternative A and Proposed Action ...........................4-199
 

Figure 4.16-3. Total project-related AADT: Alternative B and Proposed Action ...........................4-200
 

Figure 4.16-4. Total project-related AADT: Alternative C and Proposed Action ...........................4-201
 

Figure 4.16-5. Total project-related AADT: Alternative D and Proposed Action ...........................4-202
 

Figure 4.16-6. AADT, all action alternatives...................................................................................4-203
 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 xix 
 

 

 

 

 

 

 

 

 

 

 

 

 

ACRONYMS AND ABBREVIATIONS 

oF degrees Fahrenheit 

μeq/l microequivalents per liter 

μg/L micrograms per liter 

μg/m3	 micrograms per cubic meter 

μmhos/cm	 micromhos per centimeter 

AADT annual average daily traffic 

ACEC Area of Critical Environmental Concern 

ACHP	 Advisory Council on Historic Preservation 

ac-ft acre-feet 

AML appropriate management level 

ANC	 acid neutralizing capacity 

AO Authorized Officer 

APD Application for Permit to Drill 

AQTSD Air Quality Technical Support Document 

APE area of potential effect 

AQRV Air Quality Related Values 

AR4 IPCC (Intergovernmental Panel on Climate Change) Fourth Assessment Report 

ATT Artemisia tridentata ssp. tridentata (basin big sagebrush) 

ATVP	 Artemisia tridentata ssp. vaseyana and Artemisia tridentata ssp. pauciflora 

(mountain big sagebrush) 

ATW Artemisia tridentata ssp. Wyomingensis (Wyoming big sagebrush) 

AUE	 animal unit equivalent 

AUM	 animal unit month 

BA	 Biological Assessment 

BACT Best Available Control Technology 

bbl	 barrel 

Bcf billion cubic feet 

BCLLC Blankenship Consulting LLC 

BLM	 Bureau of Land Management 

BMP Best management practice 

BP BP America Corporation 

B.P. before present 

BSC biological soil crust 

CAAQS Colorado Ambient Air Quality Standards 

CaCO3 calcium carbonate 

CAMx Comprehensive Air quality Model with Extensions 

CASTNET Clean Air Status and Trends Network 

CBG Creston Blue Gap 

CBM Coalbed methane 

CBNG coalbed natural gas 

CCLUP Carbon County Land Use Plan 

CCR Carbon County Road 

CCRBD Carbon County Road and Bridge Department 

CCSD Carbon County School District 

CCVC Carbon County Visitors Council 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 xxi 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ACRONYMS AND ABBREVIATIONS
 

CDA Concentrated Development Area 

CD-C Continental Divide-Creston 

CDW2 Continental Divide/Wamsutter II 

CEM continuous emissions monitoring 

CEQ Council on Environmental Quality 

CERCLA Comprehensive Environmental Response, Compensation, and Liability Act 

CFR Code of Federal Regulations 

cfs cubic feet per second 

CH4 methane 

CIAA cumulative impact analysis area 

CO carbon monoxide 

COA condition of approval 

CRBSCF Colorado River Basin Salinity Control Forum 

CRM Coordinated Resource Management 

CSU controlled surface use 

CTL coal to liquid 

CWA Clean Water Act 

CWRRI Colorado Water Resources Research Institute 

CWR crucial winter range 

CW/Y crucial winter/yearlong 

dBA decibel 

DEIS Draft Environmental Impact Statement 

DAT deposition analysis threshold 

DIR dividends, interest, and rent 

DM Department Manual 

DOI Department of the Interior 

dv deciview 

Δdv delta deciview 

EA Environmental Assessment 

EGU electrical generating unit 

EIS Environmental Impact Statement 

EO Executive Order 

EPA Environmental Protection Agency (United States Environmental Protection Agency) 

ERP Enhanced Resource Protection Alternative 

ERMA Extensive Recreation Management Area 

ESA Endangered Species Act of 1973 

FDOP first date of production 

FLAG Federal Land Managers’ Air Quality Related Values Work Group 

FEIS Final Environmental Impact Statement 

FLM Federal Land Managers 

FLPMA Federal Land Policy and Management Act of 1976 

FMR federal mineral royalties 

ft feet 

FY fiscal year 

GHG greenhouse gas 

GIS geographic information system 

gpm gallons per minute 

GPS Global Positioning System 

xxii Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

ACRONYMS AND ABBREVIATIONS 

GDRMP Great Divide Resource Management Plan 

GWP Global Warming Potential 

HAP Hazardous Air Pollutants 

HMRRP Hazard Management and Resource Restoration Program 

HMA herd management area 

HNO3 nitric acid 

HUC hydrologic unit code 

HWA Hayden-Wing Associates, LLC 

I-80 Interstate 80 

IDLH Immediately Dangerous to Life or Health 

IDT interdisciplinary team 

IM Instruction Memorandum 

IMPROVE Interagency Monitoring of PROtected Visual Environments 

IN Initial (as in initial disturbance) 

IPCC Intergovernmental Panel on Climate Change 

IRO Interim rollover objective 

ISR in situ uranium recovery 

ISWM Integrated Solid Waste Management 

JPAD Jonah-Pinedale Anticline Development 

kg/ha-yr kilograms per hectare per year 

KMDA known mineral deposit area 

lb pound(s) 

kHz kilohertz 

KOP Key Observation Point 

LOS level of service 

LSRCD Little Snake River Conservation District 

LSRV Little Snake River Valley 

LT Long-term (as in long-term disturbance) 

LWC Lands with Wilderness Characteristics 

LWDII lost work day [due to] injuries and illness 

m3 cubic meters 

MATS Modeled Attainment Test Software 

Mcf thousand cubic feet 

MEI maximally-exposed-individual 

mg/L milligrams per liter 

MGD million gallons per day 

mi2 Square mile 

MLE most-likely-exposure 

MMBtu gigajoules 

MMcf million cubic feet 

MHSC Memorial Hospital of Sweetwater County 

MHCC Memorial Hospital of Carbon County 

MOA Memorandum of Agreement 

MOU Memorandum of Understanding 

mph miles per hour 

msl mean sea level 

NAAQS National Ambient Air Quality Standards 

NADP National Acid Deposition Program 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 xxiii 
 

 

 

 

 

 

 

 

 

 

 

ACRONYMS AND ABBREVIATIONS 

NASS National Agricultural Statistics Service 

NEPA National Environmental Policy Act 

NH4 ammonium 

NHPA National Historic Preservation Act 

NOI Notice of Intent 

NO2 nitrogen dioxide 

NO3 nitrate 

NOx nitrogen oxides 

NPDES National Pollutant Discharge Elimination System 

NRC Nuclear Regulatory Commission 

NRCS National Resources Conservation Service 

NRHP National Register of Historic Places 

NSO No surface occupancy 

NSPS New Source Performance Standards 

NSR New Source Review 

NTL Notice to Lessee 

NTN National Trends Network 

NTU nephelometric turbidity unit 

NWI National Wetland Inventory 

OHV off-highway vehicle 

OPS Office of Pipeline Safety 

OSHA Occupational Safety and Health Administration 

OSM Office of Surface Mining Reclamation and Enforcement 

OWUS Other Waters of the U.S. 

ppb parts per billion 

PCT personal current transfers 

PFC Proper Functioning Condition 

PFYC Probable Fossil Yield Classification 

PGM photochemical grid model 

PM10 particulate matter less than 10 microns 

PM2.5 particulate matter less than 2.5 microns 

PRPA Paleontological Resources Preservation Act 

PSD prevention of significant deterioration 

psi pound per square inch 

PUP Pesticide Use Proposal 

PWMTF Permanent Wyoming Mineral Trust Fund 

RCRA Resource Conservation and Recovery Act 

REL Reference Exposure Levels 

RfC Reference Concentrations for Chronic Inhalation 

RFFA Reasonably Foreseeable Future Action 

RFO Rawlins Field Office 

RIP Recovery and Implementation Plan 

RMG Reservoir Management Group 

RMP Resource Management Plan 

RMPPA Resource Management Plan Project Area 

ROD Record of Decision 

RV recreational vehicle 

SCCP Sweetwater County Land Use Plan 

xxiv Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
 

 

 

 

 

 

 

 

ACRONYMS AND ABBREVIATIONS
 

SCR Sweetwater County Road 

SCRBD Sweetwater County Road and Bridge Department 

SCSD Sweetwater County School District 

scf standard cubic feet 

SCSWDD Sweetwater County Solid Waste Disposal District 

SDLLC Sammons/Dutton Consulting LLC 

SDWA Safe DrinkingWater Act 

SEO State Engineer’s Office 

SGEO Greater Sage-grouse Core Area Protection Program 

SHPO State Historic Preservation Office 

SHWD Solid and Hazardous Waste Disposal 

SO2 sulfur dioxide 

SO4 sulfate 

SPCC Spill Prevention Control and Countermeasures 

SRMA Special Recreation Management Area 

SRP Special Recreation Permit 

SSA sole source aquifer 

STR Continental Divide-Creston Natural Gas Development Project Socioeconomic Technical Report 

SVR standard visual range 

SWEDA Sweetwater Economic Development Authority 

SWPPP Stormwater Pollution Prevention Plan 

SWR severe winter relief areas 

Tcf trillion cubic feet 

TDS total dissolved solids 

tg teragrams 

T&E Threatened, Endangered, or Candidate 

TNW Traditionally Navigable Water 

TP Transportation Plan 

TPC Transportation Planning Committee 

TPQ threshold planning quantity 

tpy tons per year 

TRC Texas Resource Consultants 

UGMA Upland Game Management Area 

UIC Underground Injection Control 

UPRR Union Pacific Railroad 

USACE U.S. Army Corps of Engineers 

USDA United States Department of Agriculture 

USDI United States Department of the Interior 

USDOT United States Department of Transportation 

USDW Underground Sources of Drinking Water 

USFS USDA—Forest Service 

USGS United States Geological Survey 

USFWS United States Fish & Wildlife Service 

UW University of Wyoming 

VIEWS Visibility Information Exchange Web System 

VRI Visual Resource Inventory 

VRM Visual Resource Management 

WAAQS Wyoming Ambient Air Quality Standards 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 xxv 
 

 

 

 

 

 

 

 

 

ACRONYMS AND ABBREVIATIONS
 

WAQSR Wyoming Air Quality Standards and Regulations 

WAS Western Archaeological Services 

WDA Wyoming Department of Agriculture 

WDEQ Wyoming Department of Environmental Quality 

WDEQ-AQD Wyoming Department of Environmental Quality—Air Quality Division 

WDEQ-LQD Wyoming Department of Environmental Quality—Land Quality Division 

WDEQ-WQD Wyoming Department of Environmental Quality—Water Quality Division 

WEAD Wyoming Department of Administration and Information, Economic Analysis Division 

WET Whole Effluent Toxicity 

WGFD Wyoming Game and Fish Department 

WHDP Wyoming Housing Database Partnership 

WHMA Wildlife Habitat Management Area 

WOGCC Wyoming Oil and Gas Conservation Commission 

WOS Wildlife Observation System 

WOSHA Wyoming Occupational Safety & Health Administration 

WoUS Waters of the U.S. 

WRAP Western Regional Air Partnership 

WRCC Western Regional Climate Center 

WRDS Water Resource Data Center 

WRS Wyoming Revised Statutes 

WSA Wilderness Study Area 

WY Wyoming State Highway 

WYDOT Wyoming Department of Transportation 

WYNDD Wyoming Natural Diversity Database 

WYPDES Wyoming Pollutant Discharge Elimination System 

xxvi Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 


EXECUTIVE SUMMARY 

BP America Production Company (BP), representing itself and more than 20 other natural gas 

development companies (collectively referred to as the “Operators”), has submitted a proposal to the U.S. 

Department of the Interior (USDI) Bureau of Land Management (BLM) Rawlins Field Office (RFO) to 

expand development of natural gas and condensate resources within two previously developed project 

areas described as the Continental Divide/Wamsutter II and Creston/Blue Gap project areas. The BLM 

has designated the new consolidated proposal the Continental Divide-Creston (CD-C) Natural Gas 

Development Project. 

The RFO has determined that the proposed project constitutes a major federal action requiring preparation 

of an Environmental Impact Statement (EIS). This EIS serves the purpose of disclosing and analyzing 

impacts resulting from the development proposed within the CD-C project area with consideration of 

identified and applied Best Management Practices (BMPs) and Conditions of Approval (COAs). A 

summary of these BMPs and COAs is included in Appendix C. 

The CD-C project area consists of approximately 1.1 million acres (1,672 square miles) in an existing 

gas-producing region between Rock Springs and Rawlins, Wyoming and bisected by Interstate 80 (Map 

ES-1). The project area is located on lands administered by the federal government (626,932 acres, 58.6 

percent) and the State of Wyoming (48,684 acres, 4.5 percent), as well as private lands (394,470 acres, 

36.9 percent), in Carbon and Sweetwater Counties. The central portion of the CD-C project area has a 

checkerboard pattern of mixed land ownership produced by grants made by the federal government in the 

19th century to the Union Pacific Railroad (UPRR) Company to spur construction of the transcontinental 

railroad. 

The Operators propose drilling up to 8,950 infill natural gas wells with a potential surface disturbance of 

47,200 acres (4.4 percent of the project area). The precise locations of the wells have not been identified 

at this time but the Operators anticipate drilling at well densities of up to one well per 40 acres. Wells 

may be drilled conventionally with a vertical well bore on a single pad or with multiple directional bores 

from a single pad. The proposed project includes construction and operation of ancillary facilities such as: 

roads; gas, water, and condensate-gathering pipelines; overhead and buried power lines; and separation, 

dehydration, metering, and fluid-storage facilities. 

More than 4,400 wells have already been drilled within the CD-C project area under previously 

authorized drilling programs; over 500 of those have been plugged and abandoned. Supporting 

infrastructure associated with the existing development includes access roads, compressor stations, a 

central gas-processing plant, water management facilities (fresh-water wells and evaporation pits, 

recycling facilities, and injection wells for produced water disposal), gas and water pipelines, and electric 

power lines. Total existing surface disturbance in the project area, including that associated with natural 

gas and other development, is estimated at 60,176 acres (5.6 percent of the project area). 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 ES-1 
EXECUTIVE SUMMARY
 

Map ES-1. Project boundary and existing natural gas development (EIS Map 1-1) 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

ES-2 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
 

 

EXECUTIVE SUMMARY
 

PURPOSE AND NEED FOR THE ACTION
 

The BLM’s purpose and need is to determine the conditions under which the applicant’s exercise of valid 

existing rights from federal oil and gas leases within the CD-C project area may be developed in 

accordance with its multiple-use mandate, the Mineral Leasing Act (MLA) of 1920 as amended by the 

Federal Land Policy and Management Act of 1976 (FLPMA), and the Federal Onshore Oil and Gas 

Leasing Reform Act of 1987. The MLA, as amended, provides that exploration and development of 

domestic oil and gas is in the best interest of the United States. The intent of the MLA and its 

implementing regulations is to allow, and essentially encourage, lessees or potential lessees to explore for 

oil and gas or other mineral reserves on federally-administered lands. The BLM will consider approval of 

the proposed drilling in a manner that reduces impacts on water, wildlife, and other resources throughout 

the CD-C project area, consistent with the lease rights granted to the applicant. 

SCOPING AND PUBLIC INVOLVEMENT 

The BLM conducted two public and internal scoping processes to solicit input and identify environmental 

issues and concerns associated with the proposed project. The first responded to a proposal by operators 

of the Creston/Blue Gap project to expand drilling in that project area, under what was titled the 

Creston/Blue Gap II project. A Notice of Intent (NOI) for the Creston/Blue Gap II proposal was published 

in the Federal Register on September 8, 2005. A public meeting was held at the Jeffrey Center in Rawlins 

on October 13, 2005, and the official scoping period ended November 15, 2005. 

Shortly after the Creston/Blue Gap II scoping process was completed, BP submitted a proposal for 

additional drilling in the Continental Divide/Wamsutter II project area. The BLM decided to combine the 

two projects and prepare a single EIS. The NOI for the combined Continental Divide-Creston Natural Gas 

Development Project was published in the Federal Register on March 3, 2006. The BLM prepared a 

scoping notice and provided copies to the public, other government agencies, and Tribes. The notice 

included information on scoping and announcement of an open house, which was held at the Jeffrey 

Center in Rawlins on April 6, 2006. The official scoping period ended May 5, 2006. 

The BLM also invited other federal, state, and local government agencies to participate in the EIS process 

as cooperating agencies. The State of Wyoming, Sweetwater County, the Little Snake River Conservation 

District, and the Sweetwater County Conservation District requested and received Cooperating Agency 

status. 

Written comments received during both public scoping periods consisted of 50 comment letters from 

federal and state agencies, non-government organizations, and one Tribe, as well as individuals and 

private corporations. 

Key issues and concerns identified through scoping are discussed and addressed in Chapters 3, 4, and 5 of 

this document, and include the following: 

 Air Quality: What are the potential project and cumulative impacts on air quality, including Air 

Quality Related Values (AQRV)? 

	 Cultural resources: Estimate the effects on the historic trails and transportation corridors in the 

project area. 

	 Water resources: What is the potential for degradation of water quality by project construction and 

drilling activities? What are the issues related to disposal of produced water associated with coalbed 

methane production? 

	 Land ownership as it affects mitigation: Opportunities to reduce impacts through mitigation may be 

complicated by land ownership patterns in the checkerboard. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 ES-3 
 

EXECUTIVE SUMMARY
 

 Non-native, Invasive Plant Species: Evaluate the current and projected presence of non-native, 

invasive species. 

 Range Resources: Evaluate the potential loss of livestock forage and project-associated hazardous 

conditions for area livestock/livestock operations. 

 Special Status Species: What are the Threatened, Endangered, or Candidate species and Sensitive 

wildlife species that could be impacted by the project and what would be the extent of the effects? 

 Socioeconomics: Define the impact of the project on traditional socioeconomic indicators such as 

employment, housing, tax revenues, and human services. 

 Surface Disturbance/Reclamation: Define the extent of existing and proposed surface disturbance 

and its effects on resources in the project area. 

 Wildlife Habitat: Evaluate the project’s effects on wildlife habitat, including fragmentation and 

subsequent effects on the value of that habitat. 

The BLM has determined that the proposed project is in conformance with BLM management plans and 

policies and is consistent with other federal and local land management plans and policies. The BLM 

will use the public comment process under the National Environmental Policy Act (NEPA) to comply 

with the public consultation requirements of Section 106 of the National Historic Preservation Act. 

PROPOSED ACTION AND ALTERNATIVES 

Chapter 2 of the EIS describes the Operators’ Proposed Action, four development alternatives, and the No 

Action alternative that are analyzed in the document. In addition to the four development alternatives 

carried forward for analysis in this EIS, two other development alternatives were considered but 

dismissed from detailed analysis. 

Proposed Action. Under the Proposed Action, up to 8,950 additional natural gas wells would be drilled 

from an estimated 6,126 well pads. Spacing of well pads would vary according to location within the 

project area. An estimated 42 percent of the future wells would be located on multiple-well pads and 

drilled to formation directionally. To fully develop the targeted resources, the Operators would 

collectively drill the new wells at the rate of approximately 600 wells per year over a period of 15 years. 

The productive life of each well is estimated to be 30 to 40 years. Combining well life with a 15-year 

production period produces a potential project life of 45 to 55 years. In support of the new wells, the 

Operators would construct additional access roads, pipelines, overhead and buried electric power lines, a 

gas processing facility, water management and disposal facilities, and equipment storage facilities. The 

total new surface disturbance for the Proposed Action would be an estimated 47,200 acres, or about 4.4 

percent of the project area. 

Alternative A: 100-Percent Vertical Drilling. Alternative A examines the possibility that all 8,950 wells 

would be drilled vertically from single-well pads. All ancillary elements of the new development would 

be the same as the Proposed Action. The estimated surface disturbance for Alternative A is 61,696 acres 

(5.8 percent of the project area), a 31-percent increase over the Proposed Action. 

Alternative B: Enhanced Resource Protection. The premise of this alternative is that some resources 

may be more at risk from intensive natural gas development and thus may require protections and 

mitigations beyond the basic measures ordinarily applied. The alternative identifies the following 

resources that may be more at risk from natural gas development: 

 Mule deer crucial winter range, 

 Pronghorn crucial winter range, 

 Greater sage-grouse lek, nesting/brood-rearing habitat, and winter concentration areas,
 

 Ferruginous hawk nesting habitat, 

ES-4 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
EXECUTIVE SUMMARY
 

 The Muddy Creek and Bitter Creek corridors and watersheds, 

 Chain Lakes alkaline wetland communities and other playas, and 

 Livestock forage. 

Each resource has basic protections provided by RFO Resource Management Plan (RMP) requirements, 

BMPs, COAs, and on right-of-way grants. This alternative would add enhanced protections to each 

Application for Permit to Drill (APD) or right-of-way grant on BLM-administered lands and federal 

mineral estate in the appropriate habitat or area of the identified resource. One of the enhanced 

protections would require that APDs in most of the identified habitats above be submitted as part of a 

development plan whose aim is to limit overall impacts. For some resources, further protections and 

mitigations would be applied only if a threshold were reached. These thresholds are defined for a specific 

percentage of habitat loss—usually 5 or 10 percent of a lease—and for a reduction of a species population 

to an unacceptable level. 

The estimated surface disturbance for the Enhanced Resource Protection Alternative is 45,516 acres 

(about 4.3 percent of the project area), slightly less than the Proposed Action. 

Alternative C: Surface Disturbance Cap – High and Low Density Development Areas. Under this 

alternative the portions of the CD-C project area that have seen the most intensive natural gas 

development to date would be designated as high-density development areas (Map 2-1 in the EIS). The 

amount of unreclaimed surface disturbance allowed per section of public land in these areas would be 

capped at 60 acres at any one time. The remainder of the project area would be designated as low-density 

development areas, with an unreclaimed surface disturbance cap of 30 acres per section at any one time. 

The 60-acre cap represents the disturbance associated with a 9-well per section drilling program (80-acre 

spacing) achieved with vertical wells only, a typical development in the high-density area; a 30-acre cap 

represents the disturbance associated with a 16-well per section drilling program (40-acre spacing) 

achieved with directional drilling. All prior natural gas surface disturbance committed to long-term use 

for roads or on-pad production facilities and all disturbance that had not been successfully reclaimed 

would count against the cap. Successfully reclaimed acreage would not count against the cap. 

About 44 percent of the CD-C project area would be within the high-density development area. The 

average historic surface disturbance within the high-density area is 33 acres per section, with an average 

of 5 wells per section. In the low-density areas, the average disturbance is 4.5 acres per section with an 

average of less than 1 well per section. About 24 percent of the CD-C project area has had no 

development to date. 

Only BLM-administered lands and mineral estate in the CD-C project area would be subject to the cap. 

The estimated surface disturbance of this alternative is 42,955 acres (about 4 percent of the project area), 

a 9-percent decrease from the Proposed Action. 

Alternative D: Directional Drilling. This alternative would require all future natural gas wells on BLMadministered lands and federal mineral estate to be drilled from multi-well pads. In areas with no existing 

oil and gas development, one multi-well pad would be permitted per section (or per lease if the lease area 

is less than a section). A single access corridor would be permitted for required roads, pipelines, and 

electrical power distribution for each new multi-well pad. In sections with existing oil and gas 

development, enlargement of one existing well pad would be permitted and that pad would serve as the 

multi-well pad for all future drilling in that section. 

Proposals for access across federal lands for oil and gas development on adjacent private and state lands 

would continue to be considered by the BLM. Operators may request that an APD be exempted from the 

general rule when an extraordinary situation exists that could limit full development of the natural gas 

resource. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 ES-5 
EXECUTIVE SUMMARY
 

The estimated surface disturbance for this alternative is 36,449 acres (about 3.4 percent of the project 

area), a 23-percent decrease from the Proposed Action. 

Alternative E: No Action. Under the No Action Alternative, it is assumed that none of the development 

activities proposed by the CD-C Operators would be approved or authorized. The analysis of the No 

Action alternative assumes that previously authorized activities would continue but that no new 

development would occur. 

Alternatives Considered but Eliminated from Detailed Analysis. The BLM considered two 

alternatives to the Proposed Action that were not carried forward for detailed analysis in this EIS—a 

Surface Disturbance Cap with Reclamation Credits and Debits alternative and a Focused Development 

alternative. 

The Surface Disturbance Cap with Reclamation Credits and Debits would have placed a 30-acre cap on 

the amount of future surface disturbance at any one time in a section of public land, with credits and 

debits for successful or failed reclamation of previous disturbance. Operators would have received a 

credit for each acre of land successfully reclaimed and a debit for each acre not yet reclaimed, thereby 

providing a reward for successful reclamation and a penalty for slow or failed reclamation. The BLM 

determined the operation of this alternative would be unpredictable and that neither the BLM nor the 

operators could rely on its results. In certain instances, the formulation could yield a cap in one section of 

perhaps 90 acres and in an adjacent section of minus 30 acres. The complexity of the alternative and the 

uncertainty of its results would promote contention between the BLM and the Operators over the meaning 

of and the operation of the cap. Because of the complexity and the uncertainty about its effects, and 

because Alternative C already satisfied all the criteria for a surface disturbance cap, the BLM decided that 

the Surface Disturbance Cap with Reclamation Credits and Debits would not be carried forward for 

analysis in the EIS. 

Several variations of a Focused Development alternative were considered during discussions between the 

Operators and the CD-C cooperating agencies between 2007 and 2009. The BLM was not a participant in 

those discussions. The concept of focused development is that drilling would be phased over time, 

focusing on completion of development within a defined area before moving to another defined area. This 

alternative would have provided opportunities to leave large tracts of wildlife habitat undeveloped for 

extended periods of time in exchange for relaxing some seasonal wildlife stipulations in the areas of 

focused development. Upon completion of development in a focus area, it would become an area with no 

activity and development would shift to the previously undeveloped area. This alternative would have 

required that the leaseholders in both the focus and undeveloped areas have a shared interest in 

developing or delaying development of their leases. With the large number of leaseholders and the 

fractured nature of land ownership in the project area, it proved impossible to reach agreement among a 

sufficient number of parties as to which properties should be developed first. The BLM concluded that 

unitization of the leases over such a large area would not be viable and thus could not provide a 

framework for focusing development. The BLM also concluded that relaxation of seasonal wildlife 

stipulations in focus areas—an essential element of such an alternative—was not appropriate. 

AFFECTED ENVIRONMENT 

Chapter 3 of the EIS describes the affected physical, biological, human, and management environment of 

the CD-C project area. The identified resources present within the project area provide the basis to 

address substantive issues of concern brought forward during internal and public scoping. Chapter 3 

provides quantitative data and spatial information where appropriate to the resource, which serves as a 

baseline for comparison of the direct, indirect, and cumulative impacts of each of the alternatives. 

Following Table ES-2 is a summary description of the Affected Environment and the Environmental 

Impacts by discipline. 

ES-6 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
EXECUTIVE SUMMARY 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 ES-7 

ENVIRONMENTAL IMPACTS: OVERVIEW 

Chapter 4 of the EIS describes the environmental effects of implementing the Proposed Action and 

alternatives on the affected environment described in Chapter 3. The chapter is divided into subsections 

that address the impacts for the resources identified during scoping. Much of the analysis of impacts for 

each resource is related to the surface disturbance associated with the Proposed Action and Alternatives A 

through D, which is over and above the existing disturbance in the project area. For Alternative E, there 

are no new impacts. The resource-specific effects of the alternatives are evaluated quantitatively and 

qualitatively, as appropriate, based on available data and the nature of the resource analyzed. 

Figure ES-1 displays initial disturbance by alternative with historical disturbance. 

Figure ES-1. Historical and projected initial disturbance, Proposed Action 

and alternatives 

0 

20,000 

40,000 

60,000 

80,000 

100,000 

120,000 

140,000 

Proposed 

Action

Alt. A Alt. B Alt. C Alt D Alt. E - No 

Action

Initial Surface Disturbance (Acres)

Historical - All Sources Initial - Incremental

Total Project Area: 

1.1 Million Acres

A comparison of the disturbance within the project area associated with the Proposed Action and the five 

alternatives is provided in Table ES-1. A brief summary of the Chapter 4 impact analysis by discipline is 

provided in Table ES-2. Following Table ES-2 is a more detailed summary description of the Affected 

Environment and the Environmental Impacts by discipline. 

. 
 

 

EXECUTIVE SUMMARY
 

Table ES-1. CD-C surface disturbance – Historical, Proposed Action and Alternatives (acres) 

Category 

Surface Disturbance 

Oil and Gas 

Grand 

Total 

Percent of 

Project 

Area 

Change from Proposed 

Action 

Well Pads 

(incl. 

roads) 

Related 

Facilities1 Total Acres % 

Historical 

Initial 

Long-term 

20,524 28,694 49,218 60,176 5.6% — — 

6,403 2,069 8,472 17,663 1.7% — — 

Proposed Action 

Initial 

Long-term 

Combined IN2 

Combined LT2 

41,889 5,311 47,200 47,200 4.4% — — 

17,998 863 18,861 18,861 1.8% — — 

62,413 34,005 96,418 107,376 10.0% — — 

24,401 2,932 27,333 36,524 3.4% — — 

Alternative A: 100-Percent Vertical Drilling 

Initial 

Long-term 

Combined IN2 

Combined LT2 

56,385 5,311 61,696 61,696 5.8% 14,496 30.7% 

23,270 863 24,133 24,133 2.3% 5,272 28.0% 

76,909 34,005 110,914 121,872 11.4% 14,496 13.5% 

29,673 2,932 32,605 41,796 3.9% 5,272 14.4% 

Alternative B: Enhanced Resource Protection Alternative 

Initial 

Long-term 

Combined IN2 

Combined LT2 

40,205 5,311 45,516 45,516 4.3% -1,684 -3.6% 

17,386 863 18,249 18,249 1.7% -611 -3.2% 

60,729 34,005 94,734 105,692 9.9% -1,684 -1.6% 

23,789 2,932 26,721 35,912 3.4% -611 -1.7% 

Alternative C: Cap on Surface Disturbance, 60 Acres and 30 Acres per Section 

Initial 

Long-term 

Combined IN2 

Combined LT2 

37,644 5,311 42,955 42,955 4.0% -4,245 -9.0% 

16,455 863 17,318 17,318 1.6% -1,543 -8.2% 

58,168 34,005 92,173 103,131 9.6% -4,245 -4.0% 

22,858 2,932 25,790 34,981 3.3% -1,543 -4.2% 

Alternative D: Directional Drilling 

Initial 

Long-term 

Combined IN2 

Combined LT2 

31,138 5,311 36,449 36,449 3.4% -10,751 -22.8% 

14,089 863 14,952 14,952 1.4% -3,908 -20.7% 

51,662 34,005 85,667 96,625 9.0% -10,751 -10.0% 

20,492 2,932 23,424 32,615 3.0% -3,908 -10.7% 

Alternative E: No Action 

Initial 

Long-term 

Combined IN2 

Combined LT2 

0 0 0 0 0.0% -47,200 -100.0% 

0 0 0 0 0.0% -18,861 -100.0% 

20,524 28,694 49,218 60,176 5.6% -47,200 -44.0% 

6,403 2,069 8,472 17,663 1.7% -18,861 -51.6% 

1

 Estimated future disturbance is unchanged under each alternative for “Related O&G Facilities,” except for No Action, which 

assumes no future disturbance. 2

 “Combined IN” equals the sum of historic initial disturbance and future initial disturbance. 

 “Combined LT” equals the sum of historic long-term disturbance and future long-term disturbance. 

ES-8 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
EXECUTIVE SUMMARY

Table ES-2. Comparison of impacts by alternative 

Feature/Resource Proposed Action 

Alternative A: 

100-Percent 

Vertical Drilling 

Alternative B: 

Enhanced 

Resource 

Protection 

Alternative C: 

Cap (High and 

Low Density 

Areas) 

Alternative 

Directiona

Drilling 

Physical Environment 

Geology The intensity of impacts on geologic resources would vary in relation to the surface disturbance by alte

in all cases providing that best management practices are followed. Impacts would not be significant. 

Paleontology 

Paleontological resources have been identified in over 30 localities within the project area. Implementa

Action or any of the action alternatives may impact paleontological resources—in a negative way by them and making them unavailable for scientific inquiry—to the extent that the ground is disturbed by d(see Table ES-1 above). Disturbance could be beneficial by resulting in the discovery and preservatio

scientific knowledge. Pre-disturbance surveys and disturbance mitigation where appropriate would minThe impact significance criterion would not be exceeded. 

Intermediate 

impact Most impact Intermediate impact Intermediate impact Lowest impa

Soils 

Impacts would be similar for the Proposed Action and all action alternatives but the extent would va

project-related disturbance, from a high of 61,696 acres under Alternative A to a low of 36,449 acres percentage of the CD-C project area soil surface that would be initially disturbed by the Proposed Actalternatives is shown below. These figures should be considered in light of the 5.6 percent of the projhas been disturbed previously. Successful implementation of mitigation measures and BMPs would incriteria were not exceeded. 

4.4 % 5.8 % 4.3 % 4.0 % 3.4 % 

Water Resources:

 Surface Water 

Under the Proposed Action and all action alternatives, surface water impacts could include contam

from the authorized and accidental discharge (spill) of fluids and produced water and the impacts (inclfrom surface disturbance related to the construction of pad sites, roads, and pipelines. The degree of prisk of adverse impacts is related directly to the amount of initial surface disturbance in each alternativ

exceeds at least one of the 8 significance criteria. The number of criteria exceeded for each alternative 

4 criteria 8 criteria 1 criterion 2 criteria 2 criteria 

Water Resources: 

Groundwater 

Significant impacts to groundwater are not expected under the Proposed Action or Alternatives beca

targeted for gas development and produced water disposal are stratigraphically isolated from aquifers flowing wells used for stock and domestic purposes, because of state-of-the-art construction techniqueimplementation of BMPs and COAs related to drilling. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
EXECUTIVE SUMMARY

Table ES-2. Comparison of impacts by alternative, continued 

Feature/Resource Proposed Action 

Alternative A: 

100-Percent 

Vertical Drilling 

Alternative B: 

Enhanced 

Resource 

Protection 

Alternative C: 

Cap (High and 

Low Density 

Areas) 

Alternative 

Directiona

Drilling 

Physical Environment, continued 

Air Quality 

Impacts from the Proposed Action and all action alternatives would not cause an exceedance of an

standard and would not exceed the Prevention of Significant Deterioration (PSD) Class II Increments a

from project sources. However, modeled impacts at a100-meter distance from field development projeshort-term concentrations that were predicted to be above the 1-hour NO2 National Ambient Air Qualit

24-hour PM2.5 NAAQS, and the 24-hour PM10 Wyoming Ambient Air Quality Standard (WAAQS). Impa

PSD Class I or Class II increments at any of the Class I and sensitive Class II areas. The visibility anamaximum of 5 days with project emissions resulting in impacts greater than the 0.5 delta deciview (Δd

Class I and sensitive Class II areas; using the 98th percentile value as a threshold, there are zero days 

threshold. There would be no nitrogen and sulfur deposition impacts that exceed BLM critical load valusensitive Class II area. In addition there would be no impacts to sensitive lakes that exceed threshold energy development projects will comply with applicable air quality regulations and standards, as dete

Biological Environment 

Vegetation 

Vegetation has already been strongly affected; historic disturbance equivalent to 5.6% of the area’s suoccurred. Additional disturbance would produce combined historic and project-related disturbance for 

each action alternative equivalent to the surface area percentages shown below. Even with successf

reclamation practices, about 40 percent of the disturbed area would remain in an unvegetated state du

for the project—45-55 years. The remaining 60 percent of the disturbed area would have reduced prod

is in progress and would have an altered species composition and density for the life of the project and 

term loss of shrubs. Estimated percentage vegetation disturbance by alternative, including the historic

10.0% 11.4% 9.9% 9.6% 9.0% 

Invasive, Non-Native Species 

Initial surface disturbance would create opportunities for invasive species and development activity wo

which such species spread throughout the project area. The principal difference in impacts for the Pro

action alternative is related to the amount of surface disturbance that would initially occur for each: 

Intermediate 

impact Most impact Intermediate impact Intermediate impact Lowest impa

Terrestrial Wildlife 

Impacts would include loss of forage, as well as direct and indirect loss of habitat. The percentage of s

crucial winter range that would be disturbed includes historic plus new. Historic disturbance is 7.3% fomule deer. Significant impact can be reached by actions that result in disruption or irreplaceable loss ohabitats such as crucial winter range and migration corridors, resulting in impacts that exceed the High 

definitions. Big game species in the area are expected to be significantly affected by the Proposed Ac

B, and C but not by Alternative D. 

ES-10 Continental Divide-Creston Natural Gas Development Project D
EXECUTIVE SUMMARY

Table ES-2. Comparison of impacts by alternative, continued 

Feature/Resource Proposed Action 

Alternative A: 

100-Percent 

Vertical Drilling 

Alternative B: 

Enhanced 

Resource 

Protection 

Alternative C: 

Cap (High and 

Low Density 

Areas) 

Alternative 

Directiona

Drilling 

Biological Environment, continued 

Pronghorn1 High Impact Extreme Impact High Impact High Impact in High Density Area Moderate Imp

Mule Deer1 High Impact Extreme Impact High Impact High Impact in High Density Area Moderate Imp

Aquatic Wildlife 

For the Proposed Action and all action alternatives, impacts to aquatic wildlife are primarily associasediment entering aquatic habitats from ground-disturbing activities and road building adjacent to or cr

significant effects are not expected. Alternative B has additional protections for the Muddy Creek/Bitteother aquatic habitats such as the Chain Lakes wetlands and playas. 

Intermediate 

impact Most impact Intermediate impact Intermediate impact Least impa

Special Status Wildlife 

Those Special Status wildlife species that have potential impacts from the Proposed Action or any of 

approaching or reaching the level of significance are identified below. Sage-grouse within core areas aaffected to a degree that approaches significance because of the SGEO's application on private and sfederal lands. 

Sage-grouse (non-core area only) 

Likely to exceed in 

non-core areas 

Likely to exceed in 

non-core areas 

Not expected to 

exceed 

Less likely to 

exceed than 

Proposed Action 

Not expected 

exceed 

Endangered Fish Impacts to the four Endangered fish found downstream of the project area are not expected to occur u

except for minor water depletion. A determination on potential water depletions is contingent on consu

Sensitive Fish 

Sensitive fish are found primarily in the Muddy Creek drainage; the likelihood of impacts to these specsignificance criteria under the Proposed Action and the action alternatives is: 

Will exceed Will exceed May exceed if actions on 

private lands offset public 

land restrictions 

Likely to 

exceed 

Less likely 

exceed 

1 The impact levels noted for Pronghorn and Mule Deer are based on WGFD (2010) definitions. Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
EXECUTIVE SUMMARY

Table ES-2. Comparison of impacts by alternative, continued 

Feature/Resource Proposed Action 

Alternative A: 

100-Percent 

Vertical Drilling 

Alternative B: 

Enhanced 

Resource 

Protection 

Alternative C: 

Cap (High and 

Low Density 

Areas) 

Alternative 

Directiona

Drilling 

Biological Environment, continued 

Special Status Plants 

Measures aimed at avoiding and protecting special-status plants that would be implemented under the 

action alternatives would insure that special-status plants would be little affected directly. To the exte

disturbance decreases and the number of disturbance sites is reduced, the likelihood of adverse impa

Wild Horses Long-term AUM (animal unit month) loss in Lost Creek and Adobe Town HMAs is estimated at: 

80 AUMs 106 AUMs 77 AUMs 73 AUMs 63 AUMs 

Human Environment 

Visual Resources 

Under the Proposed Action and all action alternatives, adequate visual mitigation in the form of BMapproval would allow oil and gas development to be compatible with the management objectives for V

the project area by partially retaining the existing character of the landscape. Development would be cVRM Class IV objectives because VRM Class IV is meant to allow for major modification of the existinlandscape. There would be no new impacts under Alternative E, No Action. 

Recreation 

The intensity of impacts to recreation would correlate to the variation in long-term surface disturbance 

Intermediate 

impact Most impact Intermediate impact Intermediate impact Least impa

Lands with Wilderness Character (LWC) 

Under the Proposed Action and all alternatives, there would be no impact on LWCs. 

Cultural and Historical Resources 

Pre-disturbance surveys and avoidance would minimize adverse impacts and remove the potential for alternatives; the number of sites that might be identified (and the number potentially eligible for NRHPalternative: 

1,888 (434) 2,467 (568) 1,821 (418) 1,718 (395) 1,455 (362

ES-12 Continental Divide-Creston Natural Gas Development Project D
EXECUTIVE SUMMARY

Table ES-2. Comparison of impacts by alternative, continued 

Feature/Resource Proposed Action 

Alternative A: 

100-Percent 

Vertical Drilling 

Alternative B: 

Enhanced 

Resource 

Protection 

Alternative C: 

Cap (High and 

Low Density 

Areas) 

Alternative 

Directiona

Drilling 

Human Environment, continued 

Socioeconomics 

The Proposed Action and the action alternatives would generate similar effects with minor differencproject-related jobs would be created by Year 15 of development. Total project-related employment (djobs) would climb to a peak of around 4,000 jobs in Year 14, an addition to existing project employmenwould continue during production after the field is fully developed, but be lower than those during devecompletion of development and production, regional employment would decrease by over 4,300 jobs, existing jobs, a net job loss. Population changes would closely follow employment gains and losses, presidents and almost 1,000 temporary workers during Year 15 of development and falling to about 700 Community facilities should be adequate to accommodate the added population but may require expaof the 15-year development cycle. Demand for community facilities would substantially diminish after dSubstantial government revenues would be generated by the natural-gas production—about $3.8 billioestimated $530 million in state mineral royalties, and $3.1 billion in ad valorem and gross products taxemployment, population, and revenue generation effects would not occur under Alternative E, No Ac

Transportation 

Development-related estimated peak annual average daily traffic (AADT) by alternative is as follows (eproduction-related AADT is the same for all alternatives, 1,360): 

> 3,900 >4,217 Reduced from PA 1-2% Reduced from PA 3-4% Reduced from 

3-11% 

Noise 

The Proposed Action and Alternatives would generate similar types of noise from construction and o

traffic-related noise. The volume of noise would be directly related to the number of well pads for each 

6,126 8,950 5,798 5,299 4,032 

Management Environment 

Range Resources 

Estimated long-term forage loss (AUM equivalent) and number of allotments at risk of exceeding signidecrease in AUMs), by alternative, are as follows: 1,985 AUMs (four allotments at risk) 

2,540 AUMs (more allotments at risk than PA) 

1,921AUMs (fewer allotments at risk than PA) 

1,832 AUMs (fewer allotments at risk than PA) 

1,574 AUMs (fewer allotmeat risk than PA

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
EXECUTIVE SUMMARY 

Table ES-2. Comparison of impacts by alternative, continued 

Feature/Resource Proposed Action 

Alternative A: 

100-Percent 

Vertical Drilling 

Alternative B: 

Enhanced 

Resource 

Protection 

Alternative C: 

Cap (High and 

Low Density 

Areas) 

Alternative 

Directiona

Drilling 

Management Environment, continued 

Oil and Gas and Other Minerals 

Under the Proposed Action and all action alternatives, the natural gas resources of the project area Natural gas reserves produced over the life of the project are estimated at 12.02 trillion cubic feet. Und

Operators would still possess lease development rights but it is assumed that fluid mineral resources wunder this proposal. 

Health and Safety The Proposed Action and all action alternatives would result in similar impacts to the public and site 

increased risk of vehicle collisions on interstate highways and local road systems. 

Waste and Hazardous Materials 

Currently authorized and approved actions are already exerting stress on the permitted and authorized proximal to the project area. Authorization of the Proposed Action or Alternatives A through C wouthe capacity of permitted waste management units used by the operating companies, including those u

solid waste, produced water, and drilling mud. Alternative D may serve to extend the life of some exis

ES-14 Continental Divide-Creston Natural Gas Development Project D
 

EXECUTIVE SUMMARY
 

SUMMARY DESCRIPTIONS: IMPACTS OF THE PROPOSED ACTION AND 

ALTERNATIVES 

Geology. The project area straddles the Continental Divide and lies within the southern and eastern parts 

of the Great Divide and Washakie sub-basins of the Greater Green River Basin. The project area has 

surface sedimentary exposures of Quaternary, Tertiary, and Late Cretaceous age including the Green 

River, Battle Spring, Wasatch, Fort Union, and Lance Formations. These deposits are underlain by 

sedimentary rocks of the Late Cretaceous age, including Fox Hills Sandstone, Lewis Shale, Mesaverde 

Group, Steele Shale, Niobrara, Frontier, and Mowry Shale. Petroleum products are generally targeted 

within the Almond, Ericson, Rock Springs, and Blair formations of the Mesaverde Group. 

Under the Proposed Action and action alternatives, there is a remote possibility that alteration of existing 

topography for well pad and access road construction could result in initiation of mass movement and 

landslides. Removal of surface vegetation and soil could accelerate erosion of surface features and result 

in gullying and siltation. The extent of impacts would be directly proportional to the amount of surface 

disturbance and would therefore vary by alternative, but would be low in all cases and would not be 

significant. Alternative A has the potential for the most impact, followed by the Proposed Action, and 

Alternatives, B, C, D, and E (No Action). 

Paleontology. The CD-C project area is underlain by geological units that have a moderate to very high 

potential to produce scientifically important fossils: the Battle Spring and Fort Union formations 

(moderate) and the Green River and Wasatch formations (very high). Paleontological resources have been 

identified in over 30 localities within the project area. Excavation of pipeline trenches and construction of 

well pads, access roads, and ancillary facilities associated with the Proposed Action or its alternatives 

could result in the exposure and destruction of these resources, either directly as a consequence of 

construction or indirectly as a result of increased erosion rates. If these newly discovered resources are 

properly recovered and catalogued, the Proposed Action and its alternatives could result in a better 

understanding and knowledge of this resource. Increased access would be available to professional, 

permitted paleontologists and geologists but could lead to increased illegal collection. Impacts to 

paleontological resources would be more likely with alternatives that have the greatest amount of 

concentrated surface disturbance, both spatially and temporally. Alternative A has the potential for the 

most impact, followed by the Proposed Action, and Alternatives, B, C, D, and E (No Action). The impact 

significance criterion would not be exceeded. 

Soils. Soils in the project area were formed from erosion of bedrock exposed at the surface and from 

lacustrine, alluvium, loess, and eolian deposits. The parent material is dominated by tertiary shales and 

sandstones and uplifted cretaceous sedimentary rock. Soils on the tertiary bedrock are poorly developed 

with little clay accumulation. Sandy soils occur on stabilized sand dunes and in areas with active dunes. 

Saline soils exist in playas, and sodic soils occur on alluvial fans derived from high-sodium parent 

materials. 

The analysis in the EIS focuses on five potential soil limitations: water erosion, wind erosion, road 

construction, runoff potential, and reclamation potential. For the first three of these limitations, soils in 

the project area were generally rated as having slight or low to moderate limitation. Nearly 70 percent of 

the project area soils are rated as having Slight potential for water erosion, 80 percent as having Moderate 

potential for wind erosion, and 63.5 percent as having a Moderate limitation for road construction. About 

half the area soils have a Moderate to High runoff potential. The most severe potential soil limitation is 

the reclamation potential. Fifty percent of the project area has Poor reclamation potential and only 21 

percent is rated as Good. The principal reasons for the Poor reclamation potential are High Soil Salinity 

(42 percent) and Soils Too Clayey (27 percent). To date, 57 percent of the wells that have been drilled 

within the CD-C project area are located within soils with poor reclamation potential. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 ES-15 
 

EXECUTIVE SUMMARY
 

Impacts of the Proposed Action and the action alternatives on soils would be directly related to the 

amount of surface disturbance created. In decreasing order of magnitude, impacts would be greatest for 

Alternative A with an estimated 61,696-acre disturbance, and then sequentially less for the Proposed 

Action (47,200 acres), Alternative B (45,516 acres), Alternative C (42,955 acres), and Alternative D 

(36,449 acres). Alternative E would have no new disturbance. Full and successful implementation of 

required mitigation measures and BMPs would insure that the significance criteria would not be 

exceeded. 

Water Resources. Approximately 70 percent of the project area is within the Great Divide Basin, a 

closed basin that is bounded by the Continental Divide on all sides and has no surface hydrologic outlet; 

29 percent is within the White-Yampa Basin that includes the Muddy Creek Sub-basin; and 1 percent is 

within the Upper Green Basin. Muddy Creek is a high-elevation, cold-desert stream and a major drainage 

system within the project area. Streamflow varies with location along the drainage. Muddy Creek exhibits 

perennial flow for the majority of its length, and in some years flows intermittently because of irrigation 

water removal south of the George Dew/Red Wash wetlands complex. In years with high runoff amounts, 

Muddy Creek flows perennially throughout its length. Flow in the tributaries to Muddy Creek is 

predominantly ephemeral, responding to localized snowmelt and rainfall events, but tributaries may also 

experience some intermittent flow due to contributions from springs and seeps. Tributary channels are 

generally dry and prone to flashy, periodic flood events from isolated thunderstorm systems from May to 

October. 

The Upper Muddy Creek Watershed/Grizzly Wildlife Habitat Management Area (WHMA) is located 

primarily east of the CD-C project area but the western-most portion lies within the CD-C project area. 

The goal of the WHMA is to “manage habitat for the Colorado River fish species unique to the Muddy 

Creek watershed” In the Grizzly WHMA, the WGFD has been working with the BLM, the grazing 

permittee, and the Little Snake River Conservation District (LSRCD) to implement similar measures. 

According to the Rawlins RMP, the area is open to oil and gas leasing with intensive management of 

surface-disturbing and disruptive activities. 

Few streams in the Great Divide Basin exhibit perennial flow. Numerous ephemeral streams flow toward 

the center of the Basin and terminate in natural or artificially constructed impoundments or disappear 

because of losses to diversions, evaporation, and/or infiltration. Since a majority of the project area is 

within this closed basin, a majority of the surface water flow originating in the CD-C project area 

terminates within the project boundary. The Chain Lakes wetlands are located in the Basin, in the north 

central portion of the CD-C project area. The Chain Lakes WHMA consists of 30,560 acres of public 

lands surface in a checkerboard pattern. 

Groundwater resources in the project area include unconfined aquifers, generally shallow, blanket-type 

deposits of Quaternary or Tertiary age found within 400–600 feet of the ground surface, and confined 

aquifers, bound by relatively impermeable rocks and in the deeper formations. The project area is located 

over the Great Divide (northern half of the project area) and Washakie (southern half) structural basins, 

with the Wamsutter Arch separating the two. 

Quaternary age aquifers within the CD-C project area likely do not qualify as Underground Sources of 

Drinking Water (USDW) since there are no wells designated for such use. The yields from these aquifers 

are not likely sufficient to sustain a public water system. Tertiary age aquifers within the CD-C project 

area qualify as USDW based on the presence of Wamsutter municipal wells and on the suitability of the 

groundwater quality. Upper Cretaceous, Lower Cretaceous, Jurassic, and Pennsylvanian age and older 

aquifers may qualify as USDW based on water quality and on the quantity. However, due to the depth of 

the aquifers in the CD-C area (2,000 to 18,000 feet) and the low population density of the area, these 

aquifers are not likely to be the target for domestic or public water system wells. 

Impacts to water resources resulting from project construction and operation could include: increased 

water runoff and downstream sediment loading as a result of surface disturbance; contamination from 

ES-16 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
EXECUTIVE SUMMARY
 

accidental releases of fluids associated with exploration and production operations, produced water, and 

other hazardous liquids to soils and surface-water systems; removal of groundwater; improper drilling and 

completion operations; and subsurface disposal of produced water. 

Impacts to surface water resulting from the Proposed Action and the action alternatives would be 

considered significant under at least one and as many as seven of the eight significance criteria, 

depending on the amount of overall surface disturbance and the locations of drill pads and associated 

roads and pipelines. Impacts for Alternative A would be the most severe and would be reduced for the 

Proposed Action and Alternative B, C, and D. Alternative D, with the least surface disturbance of the 

action alternatives and the fewest disturbance locations, would have the least significant impact. 

Impacts to groundwater are not expected to be significant because the aquifers targeted for gas 

development and produced-water disposal are located in formations below and isolated from the aquifers 

that produce springs and flowing wells utilized for stock and domestic purposes. In addition, existing 

federal and state laws and regulations provide protections that limit the potential for significant impacts 

on groundwater. 

Air Quality. The CD-C air quality analysis addressed the impacts on ambient air quality and Air Quality 

Related Values (AQRVs) from potential air emissions due to the Proposed Action and alternatives and 

from other regional emissions sources within a defined study area. Potential ambient air quality impacts 

were quantified and compared to applicable state and federal ambient air quality standards and Prevention 

of Significant Deterioration (PSD) increments, hazardous air pollutant (HAP) thresholds, and AQRV 

impacts (impacts on visibility, atmospheric deposition, and potential increases in acidification to acidsensitive lakes). 

A near-field ambient air quality impact assessment was performed to evaluate maximum pollutant 

impacts within and near the CD-C project area using EPA’s Guideline (EPA 2005) model, AERMOD, to 

estimate maximum potential impacts of carbon monoxide (CO), nitrogen dioxide (NO2), sulfur dioxide 

(SO2), particulate matter greater than 10 microns or 2.5 microns in diameter (PM10, and PM2.5) from 

project emissions sources. Near-field HAP (benzene, toluene, ethyl benzene, xylene, n-hexane and 

formaldehyde) concentrations were calculated for assessing impacts both in the immediate vicinity of 

project area emission sources for short-term (acute) exposure assessment and for calculation of long-term 

risk. 

A far-field ambient air quality impact assessment was carried out using CAMx (Comprehensive Air 

Quality Model with Extensions) to quantify potential air quality impacts to both ambient air 

concentrations of CO, NO2, SO2, PM10, PM2.5, and ozone, and AQRVs from air pollutant emissions of 

CO, nitrogen oxides (NOx), SO2, PM10, PM2.5, and volatile organic compounds (VOCs) expected to result 

from the development of the CD-C project as well as the combined effects of the CD-C project and other 

new sources of emissions in the region. 

The modeling relied on an emission inventory developed for the project for each year over the expected 

life of the project. Emission inventories for all regional emissions sources from human activities and 

natural sources (e.g. wildfires) were compiled for use in the far-field modeling. 

Near-field modeling indicated that production and field development source emissions of the Proposed 

Action and alternatives would not cause an exceedance of any ambient air quality standard and would not 

exceed the PSD Class II Increments at a 250-meter distance from project sources. However, modeled 

impacts at a100-meter distance from field development project sources did result in short-term 

concentrations that were predicted to be above the 1-hour NO2 NAAQS, the 24-hour PM2.5 NAAQS, and 

the 24-hour PM10 WAAQS. Far-field and mid-field modeling using CAMx showed that the Proposed 

Action and alternatives would not cause any exceedances of the ambient air quality standards for ozone or 

any other criteria pollutant and would not exceed the PSD Class I or Class II increments at any of the 

Class I and sensitive Class II areas. The visibility analysis indicated a maximum of 5 days with project 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 ES-17 
EXECUTIVE SUMMARY
 

emissions resulting in impacts greater the 0.5 delta deciview (Δdv) threshold at any of the Class I and 

sensitive Class II areas; using the 98th percentile value as a threshold, there would be zero days above the 

0.5 Δdv threshold. 

Vegetation. The CD-C project area is located within the Omernik Level III “Wyoming Basin” Ecoregion 

18, described generally as a broad intermontane basin dominated by arid grasslands and shrublands and 

interrupted by high hills and low mountains. Three vegetative cover types make up 78 percent of the 

project area: Wyoming Big Sagebrush (the most common at 39 percent), greasewood flats and fans (23 

percent), and saltbush flats and fans (16 percent). 

Within the project area, the ecoregion is further divided into two Level IV ecoregions: Rolling Sagebrush 

Steppe and Salt Desert Shrub Basins. The Rolling Sagebrush Steppe is a semiarid region of rolling plains, 

alluvial and outwash fans, hills, cuestas, mesas, and terraces, with average annual precipitation from 10– 

12 inches. The dominant vegetation in this ecoregion is sagebrush, often associated with various 

wheatgrasses or fescue. The ecoregion is interspersed with desert shrublands, dunes, and barren area in 

more arid regions (e.g., Red Desert); and with mixed-grass prairie at the eastern limit. The Salt Desert 

Shrub ecoregion includes disjunct playas and isolated sand dunes. The plains, terraces, and rolling alluvial 

fans of this ecoregion have soils that tend to be more alkaline and less permeable than soils in the Rolling 

Sagebrush Steppe. Vegetation is a sparse cover of xeric-adapted species such as shadscale, greasewood, 

and Gardner’s saltbush. This arid region is sensitive to grazing pressure, which may promote the spread of 

invasive weeds. 

Direct impacts to native shrub/grassland communities within the CD-C project area would be similar 

under the Proposed Action and all action alternatives—an initial reduction of herbaceous vegetation and a 

long-term loss of shrubs due to soil disturbance and related construction activities. These impacts could 

be mitigated by successful implementation of reclamation practices, but about 40 percent of the 

disturbance would remain in an unvegetated state for the life of the project—30–40 years at each 

individual well site—while used for access roads and well pad facilities. The remaining 60 percent would 

have reduced productivity while reclamation is in progress and would have an altered species composition 

and density for the life of the project and beyond, including a long-term loss of shrubs. 

Vegetation could be impacted indirectly as a result of soil compaction, mixing of soil horizons, loss of 

topsoil productivity, and increased soil-surface exposure resulting in soil loss due to wind and water 

erosion. Other indirect impacts could occur as a result of altered runoff hydrology due to roads, well pads, 

and other facilities, particularly on moderate to steep slopes. Additional indirect impacts would occur due 

to deposition of dust on vegetation near roads and construction sites, reducing plant productivity and 

vitality. The increased surface disturbance produced by project implementation would also provide 

opportunities for invasive plant species to establish and spread. 

As with soils, the principal difference in impacts among alternatives is related to the amount of surface 

disturbance that would initially occur for each. In decreasing order of magnitude, impacts would be 

greatest for Alternative A with an estimated 61,696-acre disturbance, and sequentially less for the 

Proposed Action (47,200 acres), Alternative B (45,516 acres), Alternative C (42,955 acres), and 

Alternative D (36,449 acres). Alternative E, with no new development, would have no new disturbance. 

Non-native, Invasive Plant Species. The principal invasive weeds known to occur on or near, or which 

have been treated within, the CD-C project area include: Russian knapweed (Centaurea repens), 

houndstongue (Cynoglossum officinale), halogeton (Halogeton glomeratus), hoary cress (whitetop) 

(Cardaria draba and Cardaria pubescens), perennial pepperweed (giant whitetop, Lepidium latifolium), 

spotted knapweed (Centaurea maculosa), common burdock (Arctium minus), and saltcedar (Tamarix 

spp.). The primary impact of these invasive species to the range resource is their ability to out-compete 

native species, reducing the quality of available forage for wildlife and livestock and also diminishing the 

long-term productivity, diversity, and aesthetic values of lands within the project area. In addition to their 

competitive nature, leafy spurge, Russian knapweed, halogeton, and houndstongue are poisonous. 

ES-18 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
EXECUTIVE SUMMARY
 

Halogeton was selected as a worst-case example of non-native invasive species known to exist in the CDC project area and a survey was conducted in 2007. At that time an estimated 13,353 acres (about 1.2 

percent of the project area) were infested with halogeton. Halogeton has continued to spread since the 

survey was made and the infestation as of 2012 is likely greater. 

Impacts to vegetation and range resources would occur on public lands under the Proposed Action and all 

action alternatives, due to an increase in surface disturbance that could provide more suitable habitat for 

invasive weed infestations. The risk of infestation and spread of invasive, non-native plant species within 

the CD-C project area would be similar under all alternatives because initial surface disturbance would 

create opportunities for new infestations and new development activity would increase the degree to 

which such species spread throughout the project area. The extent of impact from invasive, non-native 

species is directly related to the amount of surface disturbance that would initially occur for each 

alternative. Alternative A has the potential for the most impact, followed by the Proposed Action and 

Alternatives B, C, D, and E (No Action). In addition to the CD-C project, several other natural gas 

projects located adjacent to the project area could provide cumulative invasive species impacts. 

Additionally, three transmission-line projects are proposed to cross the project area and vehicles/ 

equipment associated with the planning and construction of those projects provide other potential seed 

sources and seed vectors. 

Wildlife. At least 396 wildlife species occur in and around the project area including: 77 mammal, 273 

bird, six amphibian, 10 reptile, and 30 fish species. Most are common and have wide distribution in the 

region. Species considered in the EIS include big game species, upland game birds, raptors, neotropical 

birds, and fish. The big game species in the project area are pronghorn, mule deer, and elk. Crucial winter 

and crucial winter/yearlong ranges of pronghorn and mule deer collectively comprise approximately 

92,842 acres (8.7 percent) of the project area. Greater sage-grouse, Columbian sharp-tailed grouse, and 

mourning doves occur within the project area. Twenty-six raptor species are known to occur in or around 

the project area, including 14 that breed or potentially breed in the project area, two that over-winter, and 

ten that have been recorded as transients or migrants. Many species of neotropical songbirds utilize the 

project area for breeding, feeding, migration, and as year-round habitats. About 30 species of fish may 

occur in the project area or in streams upstream or downstream of the project area, including ten gamefish species and 20 non-game fish species. 

Because of the long timeframe for recovery of shrub habitats after vegetation removal, terrestrial wildlife 

dependent on shrub habitats would be impacted most by habitat loss. In addition to the physical removal 

of habitat, disturbance during construction and production can displace or preclude wildlife use during all 

seasons. Timing restrictions for critical times of year have been developed for the most sensitive species 

and would generally be implemented during the development phase, but no restrictions would apply 

during the production phase. Other impacts from natural gas development include habitat fragmentation, 

reduced availability and palatability of forage due to dust, and mortality from collisions involving 

vehicles and wildlife. 

Pronghorn and mule deer are the wildlife species most impacted by development, particularly in their 

winter range where previous development has already reduced the quality of the habitat. Impacts from the 

Proposed Action and Alternatives A and C are likely to reach the level of significance for pronghorn and 

mule deer CWR and associated migration routes. 

Because the BLM places buffers around active raptor nest sites and restricts other activities around raptor 

nests and because most raptor prey use habitat that can be reclaimed in a timely fashion, the impact from 

the Proposed Action or the action alternatives is not expected to exceed the significance criteria. 

The project could result in some unintentional, direct mortality of small birds and small mammals from 

vehicle collisions; however, this mortality is expected to be negligible and is not likely to reduce 

populations within the project area. If standard prescribed environmental protection measures and BMPs 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 ES-19 
EXECUTIVE SUMMARY
 

are implemented under the Proposed Action or the action alternatives, the impacts on songbird and smallmammal populations are not expected to exceed the impact significance criteria. 

All of the fish species that are not BLM Sensitive Species have wide distribution within Wyoming. 

Consequently, the project and other human activities within the Muddy Creek and Great Basin watersheds 

may have localized population impacts but should not impact their status range-wide. 

The cumulative impact of multiple individual projects may result in a large area potentially exposed to 

increased fragmentation, disturbance of wildlife and their habitats, disruption of migratory corridors, and 

the loss of refuge areas. Additional effects are expected on wildlife dispersal, the reduction of nonfragmented habitats, competition with livestock, and competition with other wildlife species. The 

generalized increase of human presence and associated disturbance across such a broad scale are a 

concern. 

Special Status Species. The greater sage-grouse, a candidate for federal listing as Threatened or 

Endangered, is present within the CD-C project area. Four species of Endangered fish are present 

downstream of the project area, including the Bonytail (Gila elegans), Colorado pikeminnow 

(Ptychocheilus lucius), humpback chub (Gila cypha), and razorback sucker (Xyrauchen texanus). 

Potential habitats for the Endangered blowout penstemon (penstemon haydenii) and the Threatened Ute 

ladies’-tresses (spiranthes diluvialis) are present, and therefore the species are potentially present. The 

Endangered black-footed ferret is unlikely to occur within the project area; however, white-tailed prairie 

dog colonies in the Continental Divide, Dad, and Desolation Flats areas provide potential habitat and prey 

for this species and those areas have not been surveyed to confirm whether black-footed ferrets are 

present. 

The following species listed by the BLM as Sensitive are present or potentially present within the CD-C 

project area: pygmy rabbit, swift fox, white-tailed prairie dog, Wyoming pocket gopher, bald eagle, 

Brewer’s sparrow, loggerhead shrike, sage sparrow, sage thrasher, burrowing owl, ferruginous hawk, 

long-billed curlew, mountain plover, trumpeter swan, white-faced ibis, Great Basin spadefoot, northern 

leopard frog, roundtail chub, bluehead sucker, and flannelmouth sucker. 

The Proposed Action and action alternatives would disturb and alter wildlife habitat during the 15-year 

development period, in addition to the 60,176 acres previously disturbed by natural gas and other 

development. Reclamation of disturbed habitats should recover grass-dominated habitats in one to several 

years, depending on precipitation. Shrub habitats would not reach pre-disturbance levels during the life of 

the project. The greater sage-grouse, loggerhead shrike, sage sparrow, and sage thrasher, which are 

dependent on shrub habitats, would be impacted most by habitat loss. 

In addition to the physical removal of habitat, disturbance during construction and production can 

displace or preclude wildlife use during all seasons. Timing restrictions for the critical times of year have 

been developed for the most sensitive species and would generally be implemented during the 

development phase, but no restrictions would be in place during the production phase. Other impacts from 

natural gas development include habitat fragmentation, reduced availability and palatability of forage due 

to dust, and mortality from collision between vehicles and wildlife. The measures aimed at avoiding and 

protecting special status plants that would be implemented under the Proposed Action and all alternatives 

would insure that potential impacts to special status plants would be minimized or eliminated. 

Because of the protections provided by the BMPs, COAs, and occupancy/timing restrictions required for 

many special status species, the impact level of significance would likely only be reached under one or 

more of the action alternatives, but not all, for sage-grouse in non-core areas, and sensitive fish. Sagegrouse in core areas would not be significantly affected under any alternative because impacts would be 

substantially ameliorated by the application of the Core Population Area density and disturbance 

limitations and mitigations (IM WY-2012-019 and Statewide Executive Directive 2011-05 for protection 

of Greater Sage-grouse Core Areas [SWED 2011]) on private and state lands as well as federal. Given the 

ES-20 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
 

EXECUTIVE SUMMARY
 

application of this guidance, development activity would not lead to a significant impact on the sagegrouse core area populations. 

It is expected that for the Proposed Action and Alternatives A and C, significance criteria could be 

exceeded for sage-grouse outside the core area. Ferruginous hawk nests located near private or state 

surface in the checkerboard would not benefit from the entire 1-mile seasonal buffer zone but it is not 

expected that significance criteria would be exceeded as other factors such as topography could decrease 

the size of the needed buffer around nests. Other special status species should be protected sufficiently by 

the COAs, RMP requirements, and BMPs to avoid exceeding the significance level. 

Alteration of sensitive fish habitat suitability from sedimentation would result in significant impacts to 

sensitive fishes under the Proposes Action and Alternatives A and C, but not under Alternative B and 

possibly not under Alternative D. 

The cumulative effect of the CD-C project and other reasonably foreseeable future projects on greater 

sage-grouse would be substantially ameliorated by the application of the Core Population Area density 

and disturbance limitations and mitigations on private and state lands as well as federal. 

Wild Horses. The BLM protects, manages, and controls wild horses within Herd Management Areas 

(HMAs). Portions of two HMAs are located within the CD-C project area: 119,600 acres of the 251,000­

acre Lost Creek HMA in the northwest corner, and 5,826 acres of the 472,812-acre Adobe Town HMA 

along the southwest perimeter west of Baggs. Both HMAs are located within livestock grazing 

allotments, and each allotment has an allocated number of Animal Unit Months (AUMs). The primary 

direct impact to wild horses would be loss of available forage as a result of surface disturbance. Indirect 

impacts could result from increased potential for horse/vehicle collisions and increased dust as a result of 

increased traffic. Alternative A has the potential for the most impact to wild horses, followed by the 

Proposed Action, and Alternatives, B, C, D, and E (No Action). For both the Proposed Action and 

Alternative A, long-term loss of forage is estimated at less than 0.2 percent of the total forage in the 

allotment for the Lost Creek HMA and less than 0.1 percent for the Adobe Town HMA. Because the 

relative loss of forage would be so small, however, none of the grazing allotments in either HMA would 

undergo a reduction in the amount of AUMs allocated. 

Visual Resources. The CD-C project area is part of a semiarid desert dominated by patches and thickets 

of sagebrush. Colors of gray, brown, and olive characterize the vegetation, with grasses and forbs 

changing to shades of brown as they cure in the summer and fall. Soils and rock strata are shades of red, 

gray, and brown. The landscape is generally unbroken, so visual contrast draws attention wherever it 

occurs. Dune fields, playas, cuestas, occasional escarpments, and eroded streambeds create some visual 

contrast. 

Visually prominent features in the project area are the Red Desert Basin, the Chain Lakes Basin, the 

extended Delaney Rim-Wamsutter Rim cuesta-and-valley complex, and North Flat Top, the high point in 

the project area. North Flat Top, Little Robbers Gulch, and The Bluffs are prominent geologic features 

visible from Wyoming Highway (WY) 789, the major north-south road through the southern part of the 

project area. Interstate 80 (I-80) bisects the project area from east to west. Because of high traffic 

volumes, I-80 is the vantage point from which potentially the most viewers see the project area. Because 

of the extensive road network, all land within the project area is in the foreground or middle ground of 

major or other roads. 

The potentially affected scenic quality in the project area is currently low to moderate overall. Cultural 

modification due to oil and gas development has negatively affected scenic quality in seven of 15 

identified landscape-rating units that are contained wholly or in part within the project area. This is 

generally because oil and gas development disturbs existing vegetation and introduces structures whose 

unnatural forms, lines, colors, and textures contrast with the natural landscape character. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 ES-21 
 

EXECUTIVE SUMMARY
 

Sixty percent of the project area is classified by the BLM as Visual Resource Management (VRM) Class 

III. The objective of Class III is to partially retain the existing character of the landscape. The level of 

change to the landscape should be moderate; management activities may attract the attention of the casual 

observer but should not dominate the view of the casual observer. The remainder of the project area is 

classified as VRM Class IV, where the objective is to provide for management activities that require 

major modifications to the existing character of the landscape and the level of change to the landscape can 

be high. 

Visual mitigation in the form of BMPs and COAs would allow oil and gas development to be compatible 

with the management objectives for VRM Class III landscapes in the project area. Development would be 

compatible per se with VRM Class IV objectives because VRM Class IV is meant to allow for major 

modification of the existing character of the landscape. Less degradation of landscape quality would 

potentially occur under Alternatives B, C, and D and more would occur under Alternative A, when 

compared to the Proposed Action. The combination of CD-C project impacts and the Gateway South and 

TransWest transmission line right-of-way systems could create a high cumulative impact in some 

viewsheds in the VRM Class III parts of the CD-C project area. Visual impacts from CD-C and other 

planned or reasonably foreseeable development may add up to a high enough level of incompatible 

contrast with existing settings to be non-compliant with VRM Class III. 

Recreation. Big game hunting and associated off-highway vehicle use constitute the primary recreational 

uses of public lands within the project area. Pleasure driving to view wildlife, especially wild horses, is a 

secondary use that occurs mainly within the Red Desert area. There is one undeveloped recreation site at 

Little Robbers Gulch Reservoir near the southern boundary of the project area that has been in historical 

use as a group hunting camp and fishing hole. 

Impacts to recreation resulting from the Proposed Action and action alternatives would directly correlate 

to impacts to wildlife, wild horses, the visual setting, traffic, and noise. In turn, these impacts would be 

directly related to the amount of surface disturbance and the increase in surface disturbance in relation to 

existing disturbance. Overall, Alternative A has the potential for the greatest amount of impact to 

recreation, followed by the Proposed Action, and Alternatives, B, C, D, and E (No Action). The intensity 

of impacts to recreation would potentially be highest in the northern part of the project area, where natural 

gas development is less dense to date and where the Chain Lakes Wildlife Habitat Management Area and 

the large block of public land to the northwest are a resource for big game hunting and other wildlifebased recreation. 

Lands with Wilderness Characteristics (LWCs). The RFO maintains an inventory of LWCs on a 

continuing basis and relies on this inventory in the development and revision of land use plans and when 

making subsequent project level-decisions. No LWCs are located within the boundaries of the CD-C 

project area. 

Cultural and Historical Resources. Portions of the Overland and Cherokee Trails, the 1868 Union 

Pacific Railroad Grade, and the Lincoln Highway (US 30 and I-80 corridor) are located within the CD-C 

project area and eligible for listing on the National Register of Historic Places (NRHP). The BLM has 

designated a quarter-mile buffer around these linear resources and associated sites as highly sensitive. 

Natural gas development within this buffer would not be permitted. A 2-mile analysis area surrounding 

these trails and associated sites is considered as the setting. Where the setting of historic trails and 

associated sites contributes to eligibility for listing on the NRHP, actions resulting in the introduction of 

visual elements that diminish the integrity of the property’s significant historic features would be 

mitigated. BMPs would be implemented to reduce visual impacts to the setting, such as consolidation of 

facilities, use of low-profile tanks, and paint colors that blend with surrounding terrain. Increased access 

to and activity within the project area during construction associated with the Proposed Action and 

alternatives could result in increased indirect impacts to archaeological sites such as changes in erosion 

ES-22 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
EXECUTIVE SUMMARY
 

patterns, soil compaction, or vegetation removal; fugitive dust; off-road vehicle traffic associated with 

construction or maintenance activities; and increased vandalism, including illegal artifact collection. 

The amount of potential impact to historic and archaeological resources is related to the amount of surface 

disturbance. Impacts under Alternative A would be the greatest, with a potential 2,467 sites that could be 

affected. Impacts would decrease proportionately for the Proposed Action (1,888 potentially affected 

sites), followed by Alternatives B (1,821 potentially affected sites), C (1,718 potentially affected sites), 

and D (1,458 potentially affected sites). No impacts would occur under Alternative E, No Action, because 

there would be no new surface disturbance. Avoidance and mitigation would remove the potential for 

significant impacts on public lands for all alternatives. 

Socioeconomics. Implementation of the Proposed Action or other action alternatives would allow 

substantially more and higher-paced development and production activity in the CD-C project area. The 

additional development activity is assumed to extend over 15 years, and production would continue for 

30–40 years thereafter. This activity would be accompanied by increased employment associated with 

development and production activities for companies that service gas field development and production 

activities, and in other sectors of the local economy. The additional employment would result in 

concurrent increases in temporary and long-term population for communities in Carbon and Sweetwater 

counties. In turn, the additional population would require temporary and long-term housing, place 

demands on local public facilities and services, and generate increases in revenues for local business 

establishments. 

The added development and production would generate substantial tax revenues for local and state 

governments, which could fund higher public-sector operating costs and facility and service expansion in 

response to development-related demands. But the timing of the receipt of those revenues and their 

distribution would not in all cases coincide with the timing and location of demand. 

Continued natural gas development within the CD-C project area would also increase the potential for 

conflicts between natural resource development and outdoor recreation and grazing activities. Given the 

existing level of development, the incremental effects of potential conflicts and displacement are likely to 

be minor to moderate across most of the project area. However, conflicts with important environmental 

values could arise in several areas. 

All action alternatives have the potential to both positively and adversely affect local and regional 

economic diversity. Positive effects would include sustained support for existing businesses and possible 

expansion of the commercial and service sectors in response to natural gas-related increased demand; 

such expansion could also serve increases in tourism, outdoor recreation, and interstate travel. Similarly, 

the development of community and commercial infrastructure to support development-related demand 

would enhance the capacity to accommodate other economic activities in the long run. Adverse effects 

that could limit economic diversification would include increased competition for labor, increased 

housing costs, and potential effects on regional environmental amenities, particularly during the 15-year 

development period. 

The level of development contemplated by the Proposed Action and other action alternatives is contingent 

upon natural gas prices being sufficiently high to support that level of development from an economic 

perspective. The natural-gas reserves in the project area are part of a larger regional resource base. 

Consequently, periods of faster or slower-paced development would generally occur in the context of 

regional energy development expansion and decline in southwest Wyoming and indeed across much of 

the Rocky Mountain west. In other words, extended periods of elevated demand for natural gas and 

resultant high gas sales prices would generally correlate with periods of accelerated development activity 

in the project area and in other natural-gas fields in Carbon, Sweetwater, and adjacent counties. 

Conversely, extended periods of lower natural-gas demand or relatively higher availability of gas from 

other sources would result in regional slowdowns in development activity. The effects of such regional 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 ES-23 
EXECUTIVE SUMMARY
 

potentials are discussed in the 2008 Baseline Socioeconomic Technical Report and in Chapter 5 of this 

EIS. 

The BLM and Operators consider the natural gas production volumes forecast for this assessment 

technically recoverable given current technology and knowledge. The ultimate level of recovery would 

depend on natural gas prices, future improvements in technology for developing and producing gas 

resources, markets for the gas, and delivery capacity to collect, process, and deliver the gas to market. 

This assessment assumes that the forecast natural gas production volumes would be recovered, while 

acknowledging the potential for lower gas prices and corresponding lower levels of development and 

production. This assumption provides a basis for assessing reasonable potential upper bounds of effects 

on socioeconomic conditions including the fact that natural gas sales prices to support this level of 

development would also provide tax revenues to aid the state and communities in responding to 

development-related effects, as well as continued support for existing programs and services locally and 

throughout the state. 

Transportation and Access. The Proposed Action and all action alternatives would result in natural gas 

development and production-related increases in traffic on federal and state highways and county and 

BLM roads that provide access to and within the CD-C project area. The pattern of traffic increases would 

be similar for all alternatives but the level of increase would vary moderately by alternative. Each action 

alternative would result in temporary increases in annual average daily traffic on federal and state 

highways resulting from construction of ancillary facilities such as field compression facilities, a central 

pipeline compression facility, a central gas-processing/stabilization facility, and a high-pressure gas line. 

For I-80, the level of increase would be relatively modest compared to existing levels of traffic. A number 

of other reasonably foreseeable projects could generate cumulative effects on I-80; wind farm 

construction; other, smaller oil and gas development projects; power transmission lines; and an in-situ 

uranium project. The effect would be greatest during construction of the projects and the overall effect 

would depend greatly on the relative timing of the construction of the projects. 

The Proposed Action and all action alternatives would accelerate highway maintenance requirements on 

county, BLM, and private roads. The timing and level of improvements and maintenance requirements 

would be driven by the magnitude and characteristics of traffic increases on specific highways and roads. 

Some temporary increases in congestion could occur on local streets in some communities in Carbon and 

Sweetwater counties and there would be a statistical potential for increases in motor vehicle accidents, 

primarily during the 15-year development period. All action alternatives would generate similar amounts 

of revenue that could be used to fund highway and road-maintenance needs. 

Noise. Existing sources of noise in the CD-C project area include gas compression stations, livestock 

grazing operations, wind, well workover operations, and traffic along area access roads, state highways, 

and I-80. Additional noise would be generated under the Proposed Action and action alternatives by well 

site and access road construction, drilling and completion, pipeline construction, and surface-disturbing 

reclamation operations. Noise levels may at times temporarily exceed EPA thresholds in specific 

locations. The duration of noise-generating activity and dispersal of noise-generating equipment across 

the project area would be greatest under the Proposed Action. 

Directional wells are considered in the Proposed Action and Alternatives B, C, and D. Directional drilling 

may require a larger rig with larger engines operating at higher decibel and lower frequency levels 

compared to rigs for vertical drilling. Alternative A, 100-Percent Vertical Drilling, would result in the 

greatest number of generation sources. The number of days needed for drilling and completion may be 

slightly fewer compared to directional wells; however, the time savings could be negated by the amount 

of time required for a rig move. Design features of Alternative B (Enhanced Resource Protection) would 

serve to reduce noise in sensitive environments, but these reductions could be negated by the noise of 

semi/haul trucks moving drilling rigs. Alternative C could result in areas with concentrated development 

activity, where noise levels would be greater than those found in areas of more dispersed operations. The 

ES-24 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
EXECUTIVE SUMMARY
 

surface disturbance cap could slow the pace of development, especially in the high-density development 

areas, and extend development noise levels over a longer time than the Proposed Action. Alternative D 

(Directional Drilling) would result in an overall reduction in well pads and roads built and provide only 

localized areas of noise. 

Range Resources. Impacts to livestock and grazing resources would occur under the Proposed Action 

and all action alternatives. Impacts could include those caused by a reduction of total available forage due 

to road, well pad, and pipeline construction and maintenance; improperly fenced open pits; vehicle traffic; 

fugitive dust deposited on potential forage; accidental spills of potentially hazardous materials; and 

creation of suitable habitat for invasive/noxious weed infestations. Livestock may be injured or killed by 

vehicle collision, become trapped in open pipeline trenches, stray from pastures through gates left open, 

and ingest poisonous invasive species. Additionally, existing range improvements can be damaged by 

equipment and vehicles. The level of impact resulting from the Proposed Action and action alternatives 

would be related to the amount of surface disturbance that would initially occur for each alternative. 

Loss of forage in a grazing allotment due to oil and gas development could result in a long-term reduction 

of the stocking rate for the allotment if the total long-term surface disturbance exceeds 10 percent of the 

allotment area. Of the 44 allotments within or overlapping the CD-C project area, two already have 

disturbance in excess of 9 percent, and nine more have disturbance in excess of 5 percent. The Proposed 

Action and alternatives have the potential to result in a long-term reduction in the stocking rate for these 

allotments until existing and new disturbance is successfully reclaimed. For the Proposed Action, it is 

estimated that an initial forage loss equivalent to 5,488 of the total 123,910 AUMs within the CD-C 

project area could occur. AUMs lost would be recovered with successful reclamation of initial 

disturbance. Estimated forage equivalent lost for Alternative A would be 7,174 AUMs; for Alternative B, 

5,293 AUMs; for Alternative C, 4,995 AUMs; and for Alternative D, 4,238 AUMs. Under Alternative E, 

No Action, no forage loss would occur. 

Oil and Gas and Other Minerals. Under the Proposed Action and all action alternatives, recoverable 

natural gas reserves produced over the life of the project are estimated at 12.02 trillion cubic feet (Tcf); 

liquid condensate is estimated at 167.3 million barrels. With this amount of production from the target 

formations, it is expected that the oil and natural gas resource in the CD-C project area would have been 

substantially depleted, pending new technology or the discovery of new reserves. Under Alternative E, 

No Action, no more natural gas or liquid condensate would be produced in the CD-C project area. 

Health and Safety. Implementation of the Proposed Action and all action alternatives would likely result 

in an increased risk to the workforce due to the increased number of personnel in the field, the increase in 

heavy equipment use and drilling operations, and the resultant increase in vehicle traffic. Compliance 

with the State of Wyoming Department of Employment Workers Occupational Health and Safety 

(WOSHA) program rules and regulations for construction and oil and gas well drilling, well servicing, 

and well special servicing operations would aid in reducing project-related occupational hazards. Risks to 

the project workforce would decline substantially once construction, drilling, and completion are 

concluded and the project enters the production phase. The Proposed Action and all action alternatives 

would result in similar impacts to the public and site workers with regard to increased risk of vehicle 

collisions on interstate highways and local road systems during the development and production phases. 

Waste and Hazardous Materials. With the exception of produced water, most waste materials that 

would be generated at project locations are considered to be solid and classified as non-hazardous, and are 

disposed of at approved facilities offsite. Some operators recycle drilling mud between wells for re-use, 

reducing the volume to be disposed of. Completion fluids are also recycled to the extent possible to 

minimize waste disposal but are generally produced to an open pit onsite for disposal. Produced water 

within the project area would continue to be managed through the use of private and commercially 

permitted evaporation ponds and injection/disposal wells. Hazardous wastes and disposal sites are 

permitted and managed in compliance with Wyoming Department of Environmental Quality regulations. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 ES-25 
EXECUTIVE SUMMARY 

Currently authorized and approved actions are already exerting stress on the permitted and authorized 

disposal facilities near to the project area. Authorization of the Proposed Action or Alternatives A, B, or C 

would result in further stress to the capacity of permitted waste management units, including those used 

for management of solid waste, produced water, and drilling mud. Alternative D may serve to extend the 

life of some existing disposal facilities if it results in higher levels of recycling and reuse of drilling 

materials. 

ES-26 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
 

 

1. PURPOSE AND NEED 

1.1 INTRODUCTION AND REGIONAL SETTING 

BP America Production Company (BP), representing itself and more than 20 others (collectively referred 

to as the “Operators”) submitted a proposal to the U.S. Department of the Interior (USDI) Bureau of Land 

Management (BLM) Rawlins Field Office (RFO) to expand development of natural gas and condensate 

resources within two previously developed project areas described as the Continental Divide/Wamsutter 

II and Creston/Blue Gap project areas. The BLM has designated the new consolidated proposal the 

Continental Divide-Creston (CD-C) Natural Gas Development Project. 

The proposed project combines two separate proposals submitted to the BLM: 

	 In April 2005, the RFO received a proposal from Devon Energy Corporation and other federal 

leaseholders to drill up to 1,250 infill natural gas wells and associated facilities. A total of 275 

natural gas wells had previously been approved for the area in the 1994 Record of Decision (ROD) 

for the earlier Creston/Blue Gap Environmental Impact Statement (EIS) (BLM 1994). The Devon 

proposal was initiated as the Creston/Blue Gap II Natural Gas Project. 

	 In November 2005, the RFO received a proposal from BP and other federal leaseholders to drill up 

to 7,700 additional wells and associated facilities within a portion of the previously approved 

Continental Divide/Wamsutter II natural gas project area. The May 2000 ROD for the Continental 

Divide/Wamsutter II Environmental Impact Statement had approved up to 3,000 wells (BLM 2000). 

After reviewing both the Continental Divide and Creston/Blue Gap II proposals, and considering their 

concurrent timing, their proximity, and the similarity of the Proposed Actions, the BLM determined that 

the two projects should be combined into one infill project with up to 8,950 wells. 

The BLM has prepared this draft Environmental Impact Statement (EIS) to analyze the effects of the 

project’s proposed infill drilling and field development in compliance with the National Environmental 

Policy Act of 1969 (as amended) (NEPA) (42 United States Code [U.S.C.] 4321 et seq.) and the Council 

on Environmental Quality (CEQ) regulations. This EIS describes the direct, indirect, and cumulative 

impacts of existing and new development in the CD-C project area. 

The project area consists of approximately 1.1 million acres (1,672 square miles, or mi2

) located in 

Townships 14 through 24 North, Ranges 91 through 98 West, Sixth Principal Meridian, Carbon and 

Sweetwater counties (Map 1-1). The eastern boundary of the CD-C project area is about 25 air miles west 

of the city of Rawlins; the western boundary is roughly 50 miles east of the city of Rock Springs. 

Interstate 80 (I-80) generally bisects the project area. The checkerboard2

 pattern of land ownership in the 

central portion of the project area is a result of early land grants from the federal government to the Union 

Pacific Railroad Company. The BLM, the State of Wyoming, and private owners issued the oil and gas 

leases covering these lands. The RFO manages BLM surface lands and the federal mineral estate in the 

project area. The BLM manages approximately 626,932 surface acres (58.6 percent), the State of 

Wyoming owns approximately 48,684 acres (4.5 percent), and private landowners own approximately 

394,470 acres (36.9 percent), as shown in Map 1-1. The map also shows all natural gas development to 

date within and adjacent to the project area. Table 1-1 describes both the surface and mineral ownership 

within the project area. 

The checkerboard refers to the generalized land ownership pattern, characterized by alternating private and public 

ownership of sections, 20 miles either side of the Union Pacific Railroad. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 1-1 

2 
CHAPTER 1—PURPOSE AND NEED
 

Map 1-1. Project boundary and existing natural gas development 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

1-2 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
CHAPTER 1— PURPOSE AND NEED
 

Table 1-1. Estimated surface and mineral ownership in the CD-C project area 

Ownership Surface % of Project Area Mineral % of Project Area 

ACRES 

Federal 626,932 58.6 579,533 54.2 

Wyoming 48,684 4.5 74,470 7.0 

Fee 394,470 36.9 416,083 38.9

 Total 1,070,086 100.0 1,070,086 100.0 

SQUARE MILES 

Federal 980 58.6 905 54.2 

Wyoming 76 4.5 116 7.0 

Fee 616 36.9 650 38.9

 Total 1,672 100.0 1,672 100.0 

The State of Wyoming is a Cooperating Agency in this EIS, with active participation from many state 

agencies including the State Planning Office, Wyoming Game and Fish Department (WGFD), State 

Historic Preservation Office (SHPO), Wyoming Department of Environmental Quality (WDEQ), and 

Wyoming Department of Agriculture (WDA). Regional cooperating agencies include Sweetwater County, 

the Little Snake River Conservation District, and the Sweetwater County Conservation District. 

1.2 OVERVIEW OF THE PROPOSED PROJECT 

Based on current knowledge of natural gas reservoir characteristics (geology, flow from existing wells, 

anticipated recovery rates, and economics), the Operators propose drilling up to 8,950 infill natural gas 

wells, including up to 500 coalbed natural gas (CBNG) wells, in addition to the more than 4,400 wells 

already drilled in the project area (Map 1-1). The precise locations of these additional wells have not been 

identified at this time. The Operators anticipate drilling at well densities of up to one well per 40 acres. 

Wells may be drilled conventionally with a vertical well bore on a single pad, or with multiple directional 

bores from a single pad. The proposed project also includes construction and operation of ancillary 

facilities such as: roads; gas, water, and condensate-gathering pipelines; overhead and buried power lines; 

and separation, dehydration, metering, and fluid-storage facilities. 

The total number of wells drilled would depend largely on variables outside of the Operators’ control, 

such as production success, appropriate engineering technology, economic factors, commodity prices, 

availability of commodity markets, and lease stipulations and restrictions. The Proposed Action is 

explained in more detail in Chapter 2 and in Appendix B, Plan of Development. Appendix B includes 

details on project site planning, development, and operations including general plans and descriptions for 

transportation, reclamation, and hazardous materials management. Wyoming BLM standard operating 

procedures and practices currently used in all surface-disturbing activities throughout the Rawlins Field 

Office would be employed for this project (see Appendix C, Best Management Practices and 

Conditions of Approval). Additional appendices containing information related to project scoping, 

operations and procedures, mitigation, and resource-specific issues include: 

 Appendix A, Summary of Scoping Comments by Category 

 Appendix D, Paleontological Resources Program Guidance 

 Appendix E, Reclamation Guidance 

 Appendix F, Water Resources Supplemental Data 

 Appendix G, Energy by Design – Cooperative Mitigation Planning for the CD-C Gas Field 

 Appendix H, Occurrence Potential of Wildlife in the CD-C project area 

 Appendix I, Wildlife Inventory, Monitoring, and Protection Plan 

 Appendix J, Cultural Resources Management 

 Appendix K, Hazardous Materials Management Summary 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 1-3 
CHAPTER 1—PURPOSE AND NEED
 

Construction, development, production, and abandonment would comply with all applicable federal, state, 

and county laws, rules, and regulations (see Section 1.7). Best Management Practices committed to by the 

Operators on public lands include the design and construction of all new roads to a safe and appropriate 

standard to accommodate their intended use, painting of all new facilities a color that best allows the 

structures to blend in with the background, interim reclamation of well locations and access roads, and 

final reclamation and recontouring of all disturbed areas. 

1.3 PREVIOUS AND EXISTING OIL AND GAS DEVELOPMENT IN THE AREA 

The CD-C project lies in the center of a large area that has seen extensive natural gas exploration and 

development. Map 1-2 shows the boundaries of the most recent natural gas projects. The Continental 

Divide project and then the Continental Divide/Wamsutter II project were two predecessors of the CD-C 

project, both with much greater area. The Creston/Blue Gap project was another predecessor. Four other 

projects lie adjacent to, or even within, the CD-C project area: Atlantic Rim to the east, Desolation Flats 

to the southwest, Table Rock at the center west, and Luman Rim at the northwest corner. Table Rock at 

and Luman Rim are two relatively small projects approved by the Rock Springs Field Office in the last 

two years. The other and much larger predecessor and neighboring projects are summarized in Table 1-2. 

Table 1-2. Oil and gas development in and near the CD-C project area 

Project Date Approved Drilling to be 

Complete Project Acres Project Wells 

Creston/Blue Gap 1994 2014 207,746 275 

Continental Divide/Wamsutter II 2000 2015 1,061,200 3,000 

Atlantic Rim 2006 2026 270,080 2,000 

Desolation Flats 2004 2018 233,542 385 

Creston/Blue Gap Natural Gas Project. Natural gas development and production in the southeastern 

portion of the project area (Map 1-2) was analyzed and approved under the Creston/Blue Gap EIS and 

ROD (BLM 1994). The decision allowed a maximum of 275 wells on 250 locations on a 160-acre 

spacing pattern. This project is fully constructed and the CD-C Proposed Action includes infill 

development associated with the same project area. 

Continental Divide/Wamsutter II Natural Gas Project (CDW2) . The CDW2 project comprised 

approximately 1,061,200 acres—531,400 acres of federal surface, 9,800 acres of state surface, and 

520,000 acres of private surface (Map 1-2). The Proposed Action analyzed in the EIS included up to 

3,000 wells at 3,000 well locations, with approximately 1,500 miles of new roads, 1,500 miles of new 

pipeline, five compressor stations, one gas-processing facility, 10 evaporation ponds, five disposal wells, 

and 50 water wells. The ROD (BLM 2000) approved up to 2,130 wells, with the remaining 870 wells (not 

more than 435 wells or well locations on federal lands and/or federal mineral estate) to be reviewed 

pending revision of the Rawlins Resource Management Plan (RMP). With the approval of the Rawlins 

RMP in 2008, the remaining wells were authorized. This project is fully constructed and the CD-C 

Proposed Action includes infill development associated with the same project area. 

Desolation Flats Natural Gas Field Development Project. The EIS analyzed a proposal to conduct 

exploratory drilling and development of up to 385 wells and associated production and transmission 

facilities within the area known as Desolation Flats. The project area is approximately 233,542 acres, 

located within the BLM Rawlins and Rock Springs Field Offices, immediately to the southwest of the 

CD-C project area (Map 1-2). The 2004 ROD (BLM 2004) approved 385 wells at 361 locations. After an 

initial period of development, drilling activity has fallen off in recent years. 

1-4 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
CHAPTER 1—PURPOSE AND NEED
 

Map 1-2. Oil and gas development in and near the CD-C project area 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 1-5 
CHAPTER 1—PURPOSE AND NEED
 

Atlantic Rim Natural Gas Development Project. This project is located on the southeastern boundary 

of the CD-C project area, encompassing approximately 270,080 acres (Map 1-2). The 2006 ROD (BLM 

2006a) called for drilling and development of approximately 1,800 CBNG wells and 200 conventional 

gas wells on state, private, and federal lands with a density of eight wells per 640 acres. Drilling is 

expected to occur for approximately 15 years. New wells are expected to have an operational life of 30 to 

40 years. Associated facilities include access roads, gas and water collection pipelines, compressor 

stations, and electrical/power system development. After an initial period of development, drilling activity 

has fallen off in recent years. 

1.4 PURPOSE AND NEED FOR THE ACTION 

The Operators propose to develop, produce, and market natural gas and other fluid minerals from the CDC project area that are needed to meet the national domestic energy demand. Under its authority to issue 

oil and gas leases and consistent with the Great Divide Resource Management Plan (RMP), updated and 

renamed in December 2008 as the Rawlins RMP (BLM 2008a), the RFO has leased federal minerals 

within the entire project area. The BLM oil and gas leasing program encourages development of domestic 

oil and gas reserves, consistent with the BLM’s multiple-use mission. 

The BLM’s purpose and need is to determine the conditions under which the applicant’s valid existing 

rights from federal oil and gas leases within the CD-C project area may be exercised in accordance with 

the BLM’s multiple-use mandate, the Mineral Leasing Act (MLA) of 1920 as amended, the Federal Land 

Policy and Management Act of 1976 (FLPMA), and the Federal Onshore Oil and Gas Leasing Reform 

Act of 1987. The MLA, as amended, provides that exploration and development of domestic oil and gas is 

in the best interest of the United States. The intent of the MLA and its implementing regulations is to 

allow, and essentially encourage, lessees or potential lessees to explore for oil and gas or other mineral 

reserves on federally-administered lands. 

The BLM is also directed by the FLPMA to manage public lands for multiple use including recreation, 

wildlife habitat, development of timber and forest products, livestock grazing, and energy and mineral 

production such as the CD-C proposal. The BLM must consider the proposal for exploratory actions and 

full-field development of natural gas resources within the CD-C project area in a manner that meets the 

multiple-use mandate of the agency and sustains the health and productivity of public lands for the use 

and enjoyment of present and future generations. The BLM will consider approval of the proposed 

drilling in a manner that reduces impacts on water and wildlife resources throughout the CD-C project 

area, consistent with the lease rights granted to the applicant. 

1.5 DECISIONS TO BE MADE 

As a result of the analysis presented in this EIS, the BLM will decide whether to allow, and under what 

conditions to allow, the development, operation, maintenance, and reclamation of expanded development 

on federal lands and the federal mineral estate within the project area. The BLM will determine what 

levels of impacts are approved, and what Conditions of Approval, Best Management Practices, 

mitigation, monitoring, and surveying would be required. The ROD associated with this EIS will not be 

the final review or the final approval for all actions associated with this project. The BLM must review 

and authorize each component of the project that involves the disturbance of federal lands on a sitespecific basis. The methods normally used to evaluate and authorize surface-disturbing activities are an 

Application for Permit to Drill (APD), right-of-way grant, or Sundry Notice, with supporting 

environmental record of review, which would be required before any construction could occur. 

Evaluations at this level include site-specific analyses of proposed well locations, tiered to the broad-scale 

level analysis included in this EIS. 

1-6 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
 

CHAPTER 1—PURPOSE AND NEED
 

1.6 REGULATORY SETTING
 

This EIS incorporates key provisions of the FLPMA of 1976, which directs the BLM to manage public 

lands and their resource values to “best meet the present and future needs of the American people” 

(Section 103 [43 USC 1702]) and to coordinate resource management “without permanent impairment of 

the productivity of the land and the quality of the environment with consideration being given to the 

relative values of the resources and not necessarily to the combination of uses that will give the greatest 

economic return or greatest unit output” (Section 103(c) [43 USC 1702]). The FLPMA also states that it 

is appropriate that some lands be used “for less than all of the resources” (Section 103 (c) [43 USC 

1702]). 

The BLM RFO is the lead agency for this EIS because the federal lands proposed for development are 

under its jurisdiction. The BLM has provided guidance, input, participation, and independent evaluation 

during EIS preparation. Previously listed federal and state agencies and local governments participated in 

the preparation of this EIS as cooperators. The BLM, in accordance with 40 Code of Federal Regulation 

(CFR) 1506.5(a) and (c), is in agreement with the information and analyses presented in this EIS and 

approves and takes responsibility for the scope and content of this document. 

This EIS was prepared in accordance with NEPA, and CEQ regulations implementing NEPA (40 CFR 

1500–1508), and is in compliance with all applicable regulations and laws subsequently passed, 

including: USDI requirements (Department Manual [DM] 516 [516 DM 1 through 6, 11]); Environmental 

Quality (U.S. Department of the Interior 2005); guidelines listed in the BLM National Environmental 

Policy Act Handbook H-1790-1 (BLM 2008c); Guidelines for Assessing and Documenting Cumulative 

Impacts (BLM 1994); CEQs Considering Cumulative Effects under the National Environmental Policy 

Act (Council on Environmental Quality 1997). 

1.7 AUTHORIZATIONS AND PERMITS 

This section describes the general federal, state and county permitting environment in which the CD-C 

natural gas development project will operate. Table 1-3 contains a full listing of the pertinent federal, 

state and county authorizing actions and the agencies that administer them. 

Oil and gas leases on federal mineral estate are issued by the BLM consistent with regulations regarding 

federal oil and gas leasing and operations (43 CFR, Parts 3100 and 3120, respectively). Stipulations may 

be added as terms of a lease when the lease is issued to reflect management guidance established in the 

Rawlins RMP. 

Once a lease is issued, the leaseholder/operator must apply for and receive site-specific authorization(s) 

prior to drilling within the leasehold area. To meet required environmental obligations, the leaseholder/ 

operator must submit to the BLM an APD or its associated application for right-of-way so that the 

appropriate environmental review may be prepared. Environmental documents such as an Environmental 

Assessment, Categorical Exclusion, or the appropriate environmental record of review for APD or rightof-way authorizations often include site-specific Conditions of Approval that add further operational 

requirements. 

Drilling of federal minerals is subject to the BLM’s Onshore Oil and Gas Orders (43 CFR Subpart 3164 – 

Special Provisions). BLM Onshore Order Nos. 1 and 2 require an applicant to comply with the following 

conditions: 

 Operations must result in the diligent development and efficient recovery of resources; 

 All activities must comply with applicable federal, state, and local laws and regulations applicable 

to federal leases;
 

 All activities must include adequate safeguards to protect the environment; 

 Disturbed lands must be properly reclaimed; and 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 1-7 
CHAPTER 1—PURPOSE AND NEED
 

 All activities must protect public health and safety. 

Onshore Order No. 1 specifically states that lessees and operators are held fully accountable for their 

contractors' compliance with the requirements of the approved permit and/or plan (Part IV; March 7, 

2007). 

Pipeline and road rights-of-way on federal lands would be issued under the authority of the Mineral 

Leasing Act of 1920, as amended, or the FLPMA. Right-of-way grants authorizing construction of 

ancillary facilities, access roads, and pipelines would grant operators certain rights subject to the terms 

and conditions incorporated into the grant by the BLM. 

Several Executive Orders (EOs) also affect implementation of the proposed project. These EOs, which are 

binding on all government agencies, place restrictions on government approval of construction activities 

and apply to wetlands, floodplain management, migratory birds, environmental justice, and invasive 

species. 

The BLM must adhere to specific provisions regarding the draining of federal minerals from adjoining 

non-federal lands. These provisions are codified in 43 CFR 3100.2, which states that, upon determination 

that lands owned by the U.S. are being drained of oil or gas by wells drilled on adjacent lands, the BLM 

may execute agreements with the owners of adjacent lands whereby the U.S. and its lessees shall be 

compensated for such drainage. In addition, where lands in any lease are being drained of their oil and gas 

content by wells either on another federal lease, issued at a lower rate or royalty, or on non-federal lands, 

the lessee shall both drill and produce all wells necessary to protect the lease lands from drainage. 

In lieu of drilling necessary wells, the lessee may, with the consent of the BLM, pay compensatory 

royalty. These provisions are also incorporated in the lease terms contained in all federal oil and gas 

leases (Form 3100-11). A list of the major permits, approvals, and authorized actions necessary to 

construct, operate, maintain, and abandon project facilities for the Continental Divide-Creston Natural 

Gas Development Project is provided in Table 1-3. Please note that this list is intended to provide an 

overview of the key regulatory requirements that would govern project implementation. Additional 

approvals, permits, and authorizing actions may be necessary. 

1-8 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
CHAPTER 1—PURPOSE AND NEED
 

Table 1-3. Federal, state, and county authorizing actions 

AGENCY NATURE OF ACTION 

Federal Agencies 

Office of the Executive Orders 

President of the 

United States  Protection and enhancement of the cultural environment (EO 11593) 

 Floodplain management (EO 11988) 

 Protection of wetlands (EO 11990) 

 Environmental justice (EO 12898) 

 Native American sacred sites (EO 13007) 

 Invasive species (EO 13112) 

 Protection of migratory birds (EO 13186) 

 Trails for America in the 21st century (EO 13195) 

 Preserve America (EO 13287) 

 Facilitation of Hunting Heritage and Wildlife Conservation (EO 13443) 

Advisory Council on 

Historic Preservation  National Historic Preservation Act of 1966, as amended (Regulations at 36 CFR Part 

800, Protection of Historic Properties (amended August 5, 2004) 

BLM (Rawlins Field  Approves APDs, Sundry Notices and reports on wells, production facilities, disposal of 

Office) produced water, gas venting or flaring, and well plugging and abandonment for federal 

wells (MLA of 1920 [30 USC 181 et seq.]; 43 CFR 3162, Onshore Oil and Gas Orders No 

1 and No 2, Approval of Operations) 

 Grants rights-of-way to operators for gas-field development actions on BLM surfaces 

outside of federal lease or unit boundaries, and to third-party applicants (i.e., non-unit 

operator or non-lease holder) both within and outside of the unit boundary (MLA of 1920, 

as amended [30 USC 185]; 43 CFR 2880; FLPMA [43 USC 1761–177 1]; 43 CFR 2800) 

 Reviews inventories of, and impacts to, cultural resources and antiquities affected by 

undertakings and consults with the State Historic Preservation Office and the Advisory 

Council on Historic Preservation as required by Wyoming State Protocol (Antiquities Act 

of 1906 [16 USC Section 431–433]; Archaeological Resources Protection Act of 1979 [16 

USC Section 470aa–470ll]; Preservation of American Antiquities [43 CFR 3]; National 

Historic Preservation Act [NHPA[);Section 106 [36 CFR 60.4]) 

 Approves disposal of produced water from BLM/federal oil and gas wells (MLA of 1920 

[30 USC 181 et seq.]; 43 CFR 3164; Onshore Oil and Gas Order No. 7) 

 Reviews impacts on federally listed or proposed-for-listing Threatened or Endangered 

species of fish, wildlife, and plants, and consults with U.S. Fish and Wildlife Service 

(Endangered Species Act of 1973, as amended et seq. [16 USC 1531]) 

 Grants Unit Area Agreements and subsequent actions relative to the unit 

BLM Wyoming 

(Reservoir 

Management Group) 

Administers drainage protection and protection of correlative rights on federal mineral estate 

U.S. Army Corps of 

Engineers 

Issues permit(s) for placement of dredged or fill material in, or excavation of, waters of the 

U.S. and their adjacent wetlands (Section 404 of the Clean Water Act of 1972 [40 CFR 122­

123, 230]) 

U.S. Department of 

Energy 

Regulates interstate pipeline product transportation (various sections of the USC and CFR) 

U.S. Environmental 

Protection Agency  Requires Spill Prevention, Control, and Countermeasure Plans (40 CRF 112) 

 Regulates hazardous wastes treatment, storage, and/or disposal (Resource 

Conservation and Recovery Act, 42 USC 6901) 

Federal Agencies 

U.S. Fish and Reviews impacts on federally listed or proposed-for-listing Threatened or Endangered 

Wildlife Service species of fish, wildlife, and plants; coordinates impacts to migratory birds (Fish and Wildlife 

Coordination Act, 16 USC Sec. 661 et seq.; Section 7 of the ESA of 1973, as amended [16 

USC et seq.]; Bald Eagle Protection Act, as amended [16 USC 668–668dd]); Migratory Bird 

Treaty Act of 1898 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 1-9 
CHAPTER 1—PURPOSE AND NEED
 

Table 1-3. Federal, state, and county authorizing actions, continued 

AGENCY NATURE OF ACTION 

U.S. Department of 

Transportation 

Controls pipeline maintenance and operation (49CFR 191 and 192) 

State of Wyoming 

Wyoming 

Department of 

Agriculture 

Regulates weed and pest control by county agency (Wyoming Weed and Pest Control Act, 

Wyoming Statute WS 11-5-102) 

Wyoming Board of 

Land 

Commissioners/Land 

and Investment 

Office 

Approves oil and gas leases, rights-of-way for long-term or permanent off-lease/off-unit 

roads and pipelines, temporary use permits, and developments on state lands (WS 37-1­

101 et seq.) 

Wyoming  Issues Wyoming Pollution Discharge Elimination System (WYPDES) permits for 

Department of discharging wastewater and stormwater runoff (WDEQ Rules and Regulations, Chapter 

Environmental 18; Wyoming Environmental Quality Act, WS 35-11-301 through 35-11-311; Section 405 

Quality (WDEQ), of the Clean Water Act, 40 CFR 122-124) 

Water Quality 

Division  Provides administrative approval for discharge of hydrostatic test water (Wyoming 

Environmental Quality Act, WS 35-11-301 through 35-11-311) 

 Oversees conformance with all surface water standards, permits to construct, and 

permits to operate 

 Issues permits to construct settling ponds and wastewater systems including 

groundwater injection and disposal wells for non-oil and gas uses 

 Regulates off-lease disposal of drilling fluids from abandoned reserve pits (Wyoming 

Environmental Quality Act, WS 35-11-301 through 35-11-3111) 

 Grants small wastewater system permits, where applicable 

 Requires reporting of spills or releases of oil, hazardous substances and produced water 

WDEQ, Air Quality 

Division 

Issues New Source Review (NSR) permits to construct and operate all pollution emissions 

sources including compressor engines and portable diesel and gas generators (Clean Air 

Act; Wyoming Environmental Quality Act, WS 35-11-201 through 35-11-212) 

Wyoming 

Department of 

Environmental 

Quality, Solid Waste 

Division 

Issues construction fill permits and industrial waste facility permits for solid waste disposal 

during construction and operations (Wyoming Environmental Quality Act, WS 35-11-501 

through 35-11-520) 

Wyoming Issues permits for oversize, overlength, and overweight loads (Chapters 17 and 20 of the 

Department Wyoming Highway Department Rules and Regulations) 

of Transportation 

(WYDOT) 

Wyoming Oil and  Issues permits to use earthen pit (reserve pits) on nonfederal lands (WOGCC 

Gas Conservation Regulations, Section III; Rule 305) 

Commission 

(WOGCC)  Authorizes flaring or venting of gas (WOGCC Regulations, Section III; Rule 326) 

 Issues permits for Class II underground injection wells (WOGCC Regulations, Section III; 

Rule 346) 

 Regulates well plugging and abandonment (40 CFR 146; 40 CFR 147.2551) 

 Issues permit to drill, deepen, or plug back as part of the APD process (WOGCC 

Regulations, Section III; Rule 315) 

 Regulates change in depletion plans, Wyoming Oil and Gas Act (WS 30-5-110) 

 Sets minimum safety standards for oil and gas activities (WOGCC Regulations (Rules 

321-A, 327, and 328) 

1-10 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
 

CHAPTER 1—PURPOSE AND NEED 

Table 1-3. Federal, state, and county authorizing actions, continued 

AGENCY NATURE OF ACTION 

State of Wyoming 

Wyoming 

State 

Engineer's 

Office 

 Issues permits to appropriate ground and surface water (WS 41-121 through 147 (Form UW-5) 

 Issues temporary water rights for construction permits to appropriate surface water (WS 41-201, 

Form SW-1) 

Wyoming Provides consultation concerning inventory of, and impacts to, cultural resources (Section106 of 

State NHPA and Advisory Council Regulations, 36 CFR 800) 

Historic 

Preservation 

Office 

Carbon County 

 Issues driveway access permits where new roads intersect with county roads 

 Prepares road use agreements and oversize trip permits when traffic on county roads exceeds 

established size and weight limits, or where the potential for excessive road damage exists 

 Issues construction and conditional use permits for all new structures 

 Administers zoning changes where applicable 

 Provides control of noxious weeds 

 Issues permits to bore or trench county roads or for any crossing or access off a county road 

Sweetwater County 

 Requires compliance with the International Fire Code (Wyoming State Statute 35-9-121) 

 Issues Construction/Use Permits to insure all structures and uses comply with the health, safety 

and welfare standards of the Sweetwater County Development Code. (Wyoming State Statute 18­

5-201 et seq.) 

 Issues Conditional Use Permits to insure that uses such as man camps, storage of explosives, 

storage of radioactive material, temporary construction yards, gravel quarries, wastewater 

disposal facilities, solid waste disposal facilities, and similar uses comply with the health, safety, 

and welfare standards of the Sweetwater County Development Code. (Wyoming State Statute 18­

5-201 et seq) 

 Approves zone changes as necessary to ensure that the proposed use of the land is coordinated 

with the Sweetwater County Zoning Map and Land Use Plan. (Wyoming State Statute 18-5-201) 

 Issues County Road permits and licenses including road access and road crossings. (Wyoming 

State Statute 24-3-101 et seq) 

 Requires coordination with the Sweetwater County Engineering Department regarding the 

movement of heavy equipment on county roads and the proper use and maintenance of said 

roads. (Wyoming State Statute 24-3-101 et seq) 

 Coordinates on natural resource issues in the context of the Sweetwater County Conservation 

District Land and Resource Use Plan and Policy 

Sweetwater Issues small wastewater permits (Wyoming State Statute 35-11-101 et seq) 

County 

Health 

Department 

Local Requires Hazardous Materials Inventory to ensure the storage of hazardous materials is properly 

Emergency coordinated with the emergency providers (Right to Know Act, EPCRA-42-116-101 et seq) 

Planning 

Committee 

Sweetwater Provides control of noxious weeds (Wyoming Statute 1105-101 et seq) 

County 

Weed and 

Pest District 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 1-11 
CHAPTER 1—PURPOSE AND NEED
 

1.8 CONFORMANCE WITH THE RAWLINS RESOURCE MANAGEMENT PLAN 

The BLM issued its ROD for the Rawlins RMP in December, 2008. The Rawlins RMP provides direction 

for managing 3.5 million acres of BLM-administered public land and 4.5 million acres of BLMadministered federal mineral estate in Albany, Carbon, Laramie, and Sweetwater Counties, Wyoming, 

including the entire CD-C project area. The proposed CD-C development would be in conformance with 

the 2008 Rawlins RMP and the BLM decisions relating to the CD-C proposal will be in conformance 

with the RMP with one area of exception. Alternative B, Enhanced Resource Protection (Section 2.2.3) 

contains several provisions that, if included in the CD-C ROD, may require an RMP amendment. For 

example, the RMP requires “avoidance of surface-disturbing and disruptive activities within 500 feet of 

perennial waters, springs, wells and wetlands.” For Muddy Creek and its tributaries that distance would 

be increased to 0.25 miles by Alternative B. If it is determined that this or other elements from Alternative 

B are to be included in the CD-C ROD, then the CD-C ROD would initiate the necessary RMP 

amendment procedures. 

Two elements of the Rawlins RMP that affect public resource management within the CD-C project area 

may be revised before a ROD is issued on the CD-C project proposal: the management of visual resources 

and the management of greater sage-grouse habitat. 

	 The RFO’s resolution of RMP protest issues required additional planning on visual resource 

management (VRM). On April 11, 2012, the RFO published a Notice of Intent to amend the RMP 

with regard to the VRM designations. Subsequent to the completion of the RMP, the RFO updated 

the visual resource inventory for the planning area and will use the update as a baseline for a revised 

designation of VRM classes. The potential effect of this revision on management of visual resources 

on public lands in the CD-C project area is described in Section 4.11, Visual Resources. Should the 

RMP amendment for VRM designations be completed before the CD-C EIS is completed, the CD-C 

ROD will reflect changes in VRM designations for the CD-C project area. 

	 On May 28, 2010, the BLM Wyoming State Office announced its intention to prepare RMP 

amendments to revise sage-grouse and sagebrush management for the Rawlins, Rock Springs, 

Kemmerer, Pinedale, Casper, and Newcastle RMPs. Amending the RMPs would provide 

consistency in applying the BLM Wyoming sage-grouse policy and also would assure consistency 

with the Wyoming Governor’s Sage-Grouse Implementation Team’s Core Population Area 

Strategy. Should the RMP amendment for sage-grouse management be completed before the CD-C 

EIS is completed, the CD-C Record of Decision (ROD) will reflect changes in management of 

greater sage-grouse called for by the RMP amendment. 

Reasonably foreseeable development of oil and gas resources for the Rawlins Resource Area during the 

20-year life of the RMP was estimated at 8,822 wells, resulting in gross surface disturbance of 57,819 

acres and net surface disturbance of 15,472 acres including roads and pipelines. The number of wells 

drilled and the estimated disturbance acreage were included in the RMP for analysis purposes only. The 

estimates should not be construed as a cap or limit on the number of wells that could be drilled, or on the 

amount of surface disturbance resulting from the development of oil and gas resources within the resource 

area. No such constraints were intended and the RMP contains no decision that would cap drilling or 

disturbance. 

1.9 PUBLIC PARTICIPATION 

1.9.1 Scoping Process 

Council on Environmental Quality (CEQ) regulations on implementing NEPA call for an early and open 

process to determine the scope and significance of issues to be addressed in the EIS (40 CFR Sec. 

1501.7). One of the principal goals of this scoping process is to involve the public in the identification of 

issues, concerns, and potential impacts that may require detailed analysis in the EIS. The formal scoping 

1-12 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
CHAPTER 1—PURPOSE AND NEED
 

process for the Continental Divide-Creston EIS began with a Notice of Intent (NOI) to prepare an EIS on 

additional drilling in the Creston/Blue Gap natural gas field. (As described in Section 1.2, Overview of 

the Proposed Project, the Continental Divide-Creston EIS began as an EIS on just the Creston/Blue Gap 

area.) That NOI was published in the Federal Register on September 8, 2005, inviting the public to 

comment on a proposal for more extensive development in the Creston/Blue Gap II natural gas field. A 

public meeting was held in Rawlins on October 13, 2005. During the scoping period on the Creston/Blue 

Gap II Project, the BLM received 29 individual comment letters, faxes, and e-mails. 

Very soon after the Creston/Blue Gap scoping process had been completed, BLM RFO received a 

proposal from BP America Production Company (BP), representing themselves and other leaseholders, to 

further develop lease holdings in the Continental Divide/Wamsutter II natural gas area. The BLM decided 

to combine this project with the Creston/Blue Gap project into a single EIS and initiated another scoping 

process for the newly named Continental Divide-Creston EIS. The BLM published a NOI for the larger 

Continental Divide-Creston project on March 3, 2006. A public meeting to discuss the project was held in 

Rawlins on April 6. In addition to the 29 comments received during the original scoping period, 21 

comment letters, faxes, and e-mails were received for the combined Continental Divide-Creston Project. 

Most of the respondents were the same for both projects. 

As part of the scoping process, the BLM invited other federal, state, and local government agencies to 

participate in the EIS process as cooperating agencies. The RFO hosted an “interested Agency” briefing 

in January 2006 to bring the project to the attention of locally interested state, federal and local agencies. 

The State of Wyoming, Sweetwater County, the Little Snake River Conservation District , and the 

Sweetwater County Conservation District requested and received Cooperating Agency status. 

The issues and concerns identified during the process described above are described in more detail in 

Appendix A. Key issues and concerns are summarized below. 

1.9.2 Key Issues and Concerns 

All comments received during the scoping process were reviewed and analyzed. The BLM identified nine 

key or driving issues based primarily upon the potential quantity, intensity, or duration of an impact, 

and/or the degree of agency or public interest in the issue. The range of alternatives was developed in 

response to these key issues, and the potential impacts associated with these issues. 

 Air Quality: Potential project and cumulative impacts on air quality, including air quality-related 

values (AQRV). 

Estimate potential changes in emissions brought about by the project, including nitrogen oxides 

(NOx), particulate matter greater than 10 microns in diameter (PM10), and ozone. Estimate projectgenerated ozone using state-of-the-art scientific methods. Impact analysis should include evaluation 

of regional haze and visibility effects on Category I airsheds. Modeling should address cumulative 

emissions in the project area and regionally, assuming reasonably foreseeable natural gas and other 

development. 

 Cultural resources: Estimate the impact on the historic trails and transportation corridors in the 

project area. 

The Overland Trail, Cherokee Trail, UPRR, and Lincoln Highway pass through the project area. 

These trails have been inventoried and evaluated for eligibility to the National Register of Historic 

Places (NRHP), and appropriate mitigation will be developed that would preserve the setting which 

contributes to that eligibility. 

	 Hydrology: Degradation of water quality by project construction and drilling activities, issues 

related to disposal of CBM-produced water. 

The project may increase salt and sediment loads to and depletions from Colorado River 

watersheds. What will be the selenium content of produced water? It should be no higher than 2 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 1-13 
CHAPTER 1—PURPOSE AND NEED
 

micrograms per liter (μ/L) to protect fish, waterfowl, shorebirds, and other wildlife. No surface 

disposal of produced water should be allowed due to increased salt loading within the Colorado 

River basin. 

	 Land Ownership: The great majority of the project area is in the “Checkerboard,” greatly 

complicating impact reduction through mitigation. 

A number of respondents noted that mitigation efforts on public land may not be imposed on nearby 

private lands, thus undermining the success of that mitigation. Examples cited included wildlife 

winter range, surface disturbance, traffic management, and non-native species. 

	 Non-native, Invasive Plant Species: Evaluate the current and projected presence of non-native, 

invasive species. 

Already-extensive development in the project area has resulted in increased infestation by invasive 

species. The regional drought has exacerbated this situation. To what extent will further 

development of the project area increase the problem and what measures can be taken to control and 

manage the spread of invasive species? To what extent is wildlife habitat and rangeland diminished 

by invasive species? 

	 Range Resources: Loss of livestock forage and project-associated hazardous conditions to area 

livestock/livestock operations. 

Respondents indicated concerns for livestock operations in the project area. Concerns were 

generally associated with: the direct loss of forage and the associated potential for a reduction in 

permitted livestock numbers; water quality impairment; movement restrictions; alterations due to 

pipeline trenches, roads, and fences; management problems associated with the inability to access 

two-track routes from project-developed crowned-and-ditched roads; and livestock hazards from 

vehicle collisions, drinking contaminated water from project pits, entrapment in pipeline trenches, 

and the increase in fugitive dust emissions potentially causing dust-induced pneumonia. 

	 Special Status Species: What are the T&E and sensitive wildlife species that could be impacted by 

the project, and what would be the extent of the effects? 

There are resident populations of greater sage-grouse and mountain plovers and other special status 

species. If black-footed ferret populations were found in the project area, would they be affected if 

prairie dog populations were reduced? Could downstream habitat of Colorado River Endangered 

fish populations be affected by soil sedimentation or water depletions? The EIS should include 

identification and mapping of important habitats, and measures to avoid or mitigate loss of those 

habitats. 

	 Socioeconomics: Define the impact of the project on traditional socioeconomic indicators and 

examine the question of technical vs. economic recoverability of the resource. 

Some respondents expressed concern over the effect of the project on local employment, 

infrastructure, and public finance. Additional concerns focused on the development of oil and gas 

resources leading to the destruction of other economic activity like recreation and second-home 

development. One respondent questioned the advisability of complete recovery of the natural gas 

resource. 

	 Surface disturbance/reclamation: The extent of existing and proposed surface disturbance and its 

effects on all resources in the project area. 

Many respondents identified the volume and distribution of surface disturbance as an issue for 

several resources in the project area—wildlife and wildlife habitat, cultural resources, soils and 

vegetation, and range resources. Directional drilling was frequently cited as a method to minimize 

surface impacts. Proper reclamation of disturbed lands is critical to minimizing impacts on all area 

resources and reclamation in arid environments, especially during periods of drought, is challenging 

and may require specialized methods. 

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CHAPTER 1—PURPOSE AND NEED
 

 Wildlife Habitat: The project has the potential to further fragment wildlife habitat and seriously 

diminish the value of that habitat for many species. 

Previous development in the project area has created a network of roads that has already fragmented 

habitat. The Proposed Action would quadruple the number of wells and has the potential to greatly 

increase fragmentation through proliferation of access roads. What impact will this have on the 

wildlife species in the area, and in particular, pronghorn, mule deer, and elk. Examine the effects of 

natural gas production on winter range within the project area. The analysis should fully explore 

mitigation efforts to minimize habitat fragmentation and to offset losses created by fragmentation; 

mitigation measures could include limiting use to existing roads, closure of some existing roads, and 

traffic controls. The need and methodology for wildlife and habitat monitoring should be fully 

explored. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 1-15 
2. THE PROPOSED ACTION AND ALTERNATIVES 

2.1 INTRODUCTION 

The BLM identified a range of alternatives to the Proposed Action based on issues, concerns, and 

opportunities raised in public comments during scoping; interdisciplinary interaction between resource 

professionals; and collaboration with cooperating and other interested agencies. Comments on the 

Proposed Action received during the public scoping period are summarized in Section 1.9, Public 

Participation. A more detailed description of the public comments is found in Appendix A: Summary 

of Scoping Comments by Category. The alternatives to the Proposed Action that are examined in detail 

in this Draft EIS include Alternative A: 100-Percent Vertical Drilling; Alternative B: Enhanced Resource 

Protection; Alternative C: Surface Disturbance Cap—High and Low Density Development Areas; 

Alternative D: Directional Drilling; and Alternative E: No Action. The Proposed Action and the 

alternatives are described in this chapter. The BLM NEPA Handbook (H-1790-1) calls for expression of 

the BLM’s preferred alternative in the Draft EIS if one exists (BLM 2008c). The BLM does not have a 

preferred alternative for the CD-C Natural Gas Development Project at this time. The BLM believes that 

the Proposed Action and the action alternatives all have elements that would address the project purpose 

and need and will review public comment on the Draft EIS before determining a preferred alternative. A 

preferred alternative will be designated in the Final EIS. 

Although the development activities anticipated in the Proposed Action and in the alternatives would take 

place on federal, state, and private lands, BLM authority applies only to the activities that would occur on 

BLM-administered lands. Those activities on BLM-administered lands and mineral estate for the 

Continental Divide-Creston (CD-C) Natural Gas Development Project must conform to the Rawlins 

RMP. The Rawlins RMP was completed in December 2008 (BLM 2008a) and is available at 

<http://www.blm.gov/rmp/wy/rawlins/documents.html>. 

2.2 DESCRIPTION OF THE PROPOSED ACTION AND ALTERNATIVES 

2.2.1 The Proposed Action 

BP America Production Company and other operators (the Operators) propose to drill up to 8,950 wells 

on approximately 1.1 million acres of federal, private, and state mineral estate (Map 1-1). These wells 

would be in addition to the more than 4,400 wells that have already been drilled in the CD-C project area. 

Up to 500 of the proposed wells could be coalbed natural gas (CBNG) wells. The project, as defined by 

the Operators, is summarized here. For more detailed information, please see the Operators’ detailed Plan 

of Development in Appendix B. 

The proposed natural gas wells could be drilled either conventionally (with a single vertical well bore on 

each well pad) or with multiple directional well bores from a single pad. It is anticipated that all wells 

would be drilled during the 10- to 15-year period after project approval. Although actual operations are 

subject to change as conditions warrant, the Operators’ long-term plan of development is to drill at the 

average rate of approximately 600 wells per year until the resource is fully developed. The Operators 

anticipate drilling infill wells at potentially up to 40 acres per down-hole well bore. Based on existing 

reservoir and well performance information, most gas wells will be completed in the Almond Formation 

(Mesa Verde Group), although secondary reserves may be encountered in other formations (e.g. Lewis, 

etc.). The average life of a well is expected to be 30 to 40 years. Combining well life with a 15-year 

production period produces a potential project life of 45 to 55 years. Factors outside of the Operators’ 

control, including geologic characteristics, reservoir quality, engineering technology, and economic 

conditions could affect the Operators’ ability to adequately drain the reservoir and could result in fewer 

than 8,950 wells being drilled. 

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CHAPTER 2—THE PROPOSED ACTION AND ALTERNATIVES
 

The facilities required by the project would include: roads; gas, water, and condensate gathering 

pipelines; overhead and buried power lines; production facilities (separation, metering, treating, fluid 

storage, compression, artificial lift, etc.); disposal well and/or surface disposal facilities; equipment 

storage facilities; and other associated facilities. In general, gas would be transported via subsurface 

pipelines to centralized compression and treatment facilities, although some well-site compression may be 

included on an as-needed basis. Produced water would be transported by truck to water-disposal wells or 

evaporation ponds, or by pipeline to treatment facilities. Existing arterial roads would provide the main 

access to and within the project area. 

2.2.1.1 Construction Activities 

Since much of the project would largely be an infill development in an existing natural gas field, new 

road construction would not be extensive. The primary access to the project area is Interstate 80 (I-80). 

Existing arterial roads, including Wyoming State Highway (WY) 789 and several Sweetwater and Carbon 

county roads, provide access within the project area. New road construction would primarily be short 

sections of road from the existing road network to new well sites and support facilities. Some existing 

access roads may need to be improved to accommodate increased traffic. Specific locations for access 

roads are not known at this time but will be included in permit applications and will be evaluated by the 

BLM during onsite inspections. 

The project would include the construction of 8,950 well bores from both single-well pads and well pads 

with multiple directional well bores. Construction of a typical single-well pad would require 

approximately 6.3 acres, which includes 0.9 acres for an access road. A typical multiple-well pad would 

disturb approximately 2.45 acres per well bore, which includes 0.45 acre for an access road. Operators 

will determine the locations of new wells according to the subsurface reservoir, the topography of the 

area, and Wyoming Oil and Gas Conservation Commission (WOGCC) spacing rules. Dimensions of drill 

pads will depend on topography and specific well needs. 

Table 2.4-1 shows the estimated surface disturbance for the Proposed Action and the alternatives to the 

Proposed Action. 

2.2.1.2 Drilling and Completion 

Well-drilling and completion activities will be in compliance with Federal Onshore Oil and Gas Order 

No. 2. These guidelines specify the following: 

...proposed casing and cementing programs shall be conducted as approved to protect or isolate all 

usable water zones, potentially productive zones, lost-circulation zones, abnormally pressured zones, 

and any prospectively valuable deposits of minerals. Any isolating medium other than cement shall 

receive approval prior to use. 

The Operators anticipate that the drilling-rig count within the project area would be up to 25 rigs at any 

particular time in order to achieve development objectives. Wells would be drilled utilizing conventional, 

mechanically powered mobile drilling rigs. Drilling each gas well would take from 7 to 20 days, with 

additional time likely for directional wells and wells deeper than 10,000 feet. The Operators propose to 

drill year-round subject to environmental considerations. 

Approximately 20,000 to 30,000 barrels (bbls) of water are needed to perform drilling operations for each 

well. Fresh water would be used for drilling the first 5,000–7,000 feet of each gas well, and water-based 

muds would be used for the remainder of the drilling operation. Water would come from existing and new 

water-supply wells within the project area, as well as from produced-water sources. The use of produced 

water to the greatest extent possible would conserve fresh-water aquifers. No water would be withdrawn 

from surface waters of the project area. 

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A fenced reserve pit, approximately 10 to 12 feet deep, would be excavated within the pad to temporarily 

store drilling fluids and cuttings. The reserve pit would be lined if so specified in the APD; in nonenvironmentally sensitive areas and when a fresh water-based drilling mud is used, the reserve pit may be 

unlined pending evaluation of the distance to surface water, depth to useable ground water, soil type and 

permeability, and anticipated types of fluids that would be contained in the pit. Reserve pits would be 

constructed so as minimize the potential to leak, break, or allow discharge and in accordance with APD 

Conditions of Approval (COAs). The reserve pit would be fenced on three sides during drilling operations 

and on the fourth side when the rig moves off the location. On producing wells, the reserve pit would be 

reclaimed per the requirements specified in the approved APD. Reserve pits may be re-used for multiple 

wells being drilled from a single pad. Although not specified in the Operators’ Plan of Development, the 

use of closed-loop drilling systems that allow for reuse of drilling fluid and remove the need for a reserve 

pit may be implemented. 

Drilling operations require approximately 8 to 10 personnel and six vehicles on location at any given time 

each day during normal operations. An additional 10 to 15 personnel and six vehicles would be required 

on location during the running and cementing of production casing. A cementing plan is submitted with 

the drilling plan as part of the Application for Permit to Drill (APD). This plan is reviewed by the BLM 

and/or the WOGCC. 

When production casing has been cemented in place, completion operations would begin. In general, 

completion consists of perforating the production casing, pressure testing, stimulation of the formation 

utilizing hydraulic fracturing technology, flow-back of fracturing fluids, flow testing to determine postfracture productivity, and installation of production equipment to facilitate hydrocarbon sales. 

Hydraulic fracture stimulation is required on the majority of wells in the project area during completion 

operations in order to enhance productivity. Combinations of fluids and proppants are pumped down the 

well bore through the perforations in the casing, and into the formation to optimize stimulation. One 

common stimulation technique utilizes gelled fresh water (with CO2 and/or N2 frequently added for 

reservoir protection and enhanced flowback) and fracture proppants to provide bridging and increased 

permeability. Sand, resin-coated sand, ceramics, or bauxite can be used as proppants. Gels and other 

chemical additives provide fluid viscosity. Sufficient rate and pressure are reached to induce a fracture in 

the target formation. The proppant carried in the fluid serves as a bridge to keep the created fracture open 

and to provide a flow path that allows reservoir fluids to move more readily into the well bore. Water 

used for stimulation purposes generally comes from water supply wells. Stimulation fluids recovered 

during flow back and subsequent production operations are temporarily contained in the completion, 

flare, or reserve pit. As discussed under Drilling Operations in Section 4.4.4.1, the hydraulic fracturing 

process is currently being regulated or is being evaluated by the EPA, the BLM, and the WOGCC. 

In May of 2012, the BLM proposed a new rule under 43 CFR Part 3160 (BLM 2012a) to regulate 

hydraulic fracturing on public and Indian lands. The rule would (1) provide disclosure to the public of 

chemicals used in hydraulic fracturing on these lands, (2) strengthen regulations related to well bore 

integrity, and (3) address management and storage of flowback water. In April of 2012, the EPA issued 

final rules that include the first federal air quality standards for natural gas wells that are hydraulically 

fractured, along with requirements for several other sources of pollution in the oil and gas industry (EPA 

2012a). 

Completion and testing operations typically require approximately 10 to 20 (up to 30) days to perform, 2 

to 30 personnel, and 1 to 20 vehicles on location. Approximately 4,000–12,000 bbls of water per well 

would be needed for completion and testing operations. Drilling and completion activities together would 

require 24,000-42,000 bbls of water per well. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 2-3 
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2.2.1.3 Production Facilities 

Production facilities on the well pad would typically include wellhead valves and piping, separation, 

dehydration, metering equipment, oil and water production tanks, a methanol storage tank and pump, and 

telemetry equipment. Production equipment would be fueled by natural gas or electricity. Telemetry 

equipment is currently used or planned for use by most Operators to improve well evaluation and 

operational efficiency, and to minimize well visits. Production pits would not be used. Well-site 

compression could be utilized on an as-needed basis. Buried natural gas gathering lines would be installed 

to transport produced gas from new wells to the existing gas-gathering pipeline system. The Operators 

would continue to use existing natural gas transmission pipelines that serve the project area. New natural 

gas transmission pipelines are not included as a component of the proposed project. 

The project may also include the development of an overhead electrical system to provide commercial 

power to portions of the field, as well as lower-voltage, buried power utilities to individual well pads. The 

overhead system is estimated to include approximately 36 miles of line. 

2.2.1.4 Pipelines 

The Operators would use existing natural gas transmission lines that serve the project area. Operators are 

not responsible for the construction or operation of gas transmission lines, and new transmission lines are 

not included as a component of the CD-C project. 

Gathering lines would be installed below the surface to transport the produced gas from the new wells to 

the gas gathering pipeline system. The gas production lines would be located adjacent and parallel to well 

access roads where possible to minimize surface disturbance. New pipelines would cross federal, state, 

and private surfaces in a route developed to minimize both resource conflicts and development costs. 

Pipeline construction consists of trenching, pipe stringing, bending, welding, coating, lowering pipeline 

sections into the trench, and backfilling. In general, construction widths would be 50 to 75 feet when not 

adjacent to a road and 25 to 50 feet when adjacent to an existing or new road. Newly constructed 

pipelines would be hydrostatically tested to ensure structural integrity. As an example of water 

requirements, approximately 2,700 gallons of water would be required to test one mile of four-inch 

pipeline. Hydrostatic test water would be disposed of as approved by the BLM and/or the State. 

2.2.1.5 Compression, Gas Treatment, and Ancillary Facilities 

Because the existing compression infrastructure in the project area would not provide sufficient capacity 

to compress the additional gas volumes anticipated from the CD-C project, supplemental compression 

would be required at various locations throughout the project area. An estimated 24,936 horsepower (hp) 

of additional compression may be needed as the project is developed for dedicated compressor sites and at 

well sites. The additional compressor sites, including a large central pipeline compression facility and 

possibly some well-site compression, could add up to 60 acres of disturbance. 

It is anticipated that one additional central gas-processing/stabilization facilities would be needed within 

the project area, affecting up to 30 acres. 

2.2.1.6 Produced-Water Disposal 

Produced water from conventional natural gas production may be stored in tanks at the well site prior to 

transport by water-hauling trucks or transported in flowlines to collection facilities for disposal. All 

produced water disposal would be in accordance with applicable WOGCC and WDEQ requirements and 

approved under BLM Sundry Notice, as appropriate. An estimated 30 new injection wells and 20 

produced water handling facilities would be constructed to dispose of produced water. The Operators 

have no plans for surface discharge of produced water. Conventional wells in the project area average 18 

bbls/day of produced water. Produced water, condensate, and gas would be separated at the well site or at 

2-4 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
CHAPTER 2—THE PROPOSED ACTION AND ALTERNATIVES
 

central facilities. Depending on the method of disposal, permits are required from WDEQ-WQD (surface) 

or WOGCC (subsurface) for disposal of produced water. 

This document does not analyze the disposal of produced water from CBNG development. The volume of 

water produced in CBNG development is typically and initially much greater than for conventional gas 

production. CBNG-produced water might be stored onsite in a lined pit or storage tank, or watercollection lines might be installed to transport water to a water-treatment facility, evaporation ponds, 

injection wells, subsurface drip areas and/or approved discharge points. The actual volumes produced and 

the methods by which the produced-water would be managed are greatly dependent on the site-specific 

development proposals, and it would be speculative for the BLM to analyze this aspect of CBNG 

development in detail in this EIS. For that reason, this document does not contain any description of 

produced-water disposal for CBNG development and does not analyze the impacts of such development. 

When the BLM receives site-specific CBNG proposals in the CD-C project area, those proposals, 

including their produced water treatment, will be analyzed in a future NEPA document. 

Interim reclamation on well pads and roads would begin as soon as possible after the well is put into 

production. The reserve pit, that portion of the well location and access road not needed for production 

operations, and pipeline corridors would be reclaimed according to the requirements specified in the 

approved APDs. Well pads and roads would be reclaimed and reseeded back to the minimum size 

required. 

When production at a well site is completed, the Operators would cut off the casing three feet below the 

final graded ground level and cap it. All surface equipment would be removed from the site and the 

surface would be recontoured to its original appearance, to the extent possible. Topsoil would be 

distributed over the location to blend the site in with its natural surroundings. All surface disturbance 

would then be planted with an appropriate seed mixture. Reclaimed sites would be monitored to ensure 

erosion is prevented and/or controlled and the desired plant species are being re-established. Monitoring 

would continue until the reclamation is deemed successful. 

2.2.1.7 Operator-Committed Practices 

Plan of Development. The Operators’ Plan of Development indicates that they would adhere to all lease 

and APD conditions, as well as all federal and state laws, regulations, and policies implemented through 

statute and/or resource management planning decisions implemented through NEPA. The Operators 

specifically cite BLM Instruction Memorandum No. 2004-194, Integration of Best Management Practices 

into Application for Permit to Drill Approvals and Associated Rights-of-Way, and note that Best 

Management Practices (BMPs) to be considered in nearly all circumstances include the following: 

 Interim reclamation of well locations and access roads soon after the well is put into production; 

 Painting of all new facilities a color which best allows the facility to blend with the background, 

typically a vegetated background; 

 Design and construction of all new roads to a safe and appropriate standard, “no higher than 

necessary” to accommodate their intended use; and 

 Final reclamation recontouring of all disturbed areas, including access roads, to the original contour 

or a contour that blends with the surrounding topography. 

 The Operators commit to performing these environmental protection measures during the 

implementation of their proposed project. Appendix C includes a summary description of the 

BMPs and APD COAs typically used by the BLM in the Rawlins Field Office to implement the 

federal laws, regulations, and policy aimed at mitigating environmental impacts. 

Air Quality. During preliminary near-field air dispersion modeling analyses of CD-C project emissions 

it was apparent that the nitrogen dioxide (NO2) concentration impacts were above the 1-hour NO2 

National Ambient Air Quality Standards (NAAQS) for modeling scenarios that included drill rig 

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CHAPTER 2—THE PROPOSED ACTION AND ALTERNATIVES
 

engines with Tier 0 emissions levels, and it was necessary to consider drill rig engines with at least Tier 

2 emissions levels in order to demonstrate compliance with the 1-hour NO2 NAAQS. Therefore the CDC Operators committed to using a minimum of Tier 2 drill rig engines for drilling operations. This 

commitment will be included and become enforceable in the Record of Decision. 

2.2.2 Alternative A: 100-Percent Vertical Drilling 

Although not stated explicitly, the Operators’ Proposed Action assumes a substantial amount of 

directional drilling. Approximately 42 percent of the 8,950 wells to be drilled would be located on 

multiple-well pads and drilled to the target formation directionally; the other 58 percent would be located 

on single-well pads and drilled vertically. The estimated surface disturbance that would result from the 

Proposed Action would be reduced because of the directional drilling. However, the proposal contains no 

commitment on the part of individual Operators or the group as a whole to implement that amount of 

directional drilling. The directional drilling included in the proposal is tied to the current plans of 

individual Operators and could change as Operators, leaseholders, or conditions change. 

In order to examine the possibility that all 8,950 wells would be drilled from single-well pads, the BLM 

developed Alternative A, with 100-percent vertical drilling. All other elements of the CD-C project would 

remain as described in the Proposed Action. With the assumption of 100-percent vertical drilling, the 

estimated surface disturbance is increased by 31 percent, from a project total of 47,200 acres to 61,696 

acres. 

Table 2.4-1 shows the estimated surface disturbance for this alternative along with the Proposed Action 

and the other alternatives. 

2.2.3 Alternative B: Enhanced Resource Protection 

Environmental protection and mitigation of environmental impacts are important aspects of the BLM’s 

management of natural gas development on public lands. The RFO has a suite of basic protections that are 

used to minimize the effects on resources. Restrictions and limitations called for by the Approved 

Rawlins Resource Management Plan (RMP) are imposed prior to development activities. Additionally, a 

number of standard operating procedures and Best Management Practices are implemented as needed. 

These are described below and throughout the description of Alternative B as Basic Protections. The 

premise of the Enhanced Resource Protection Alternative is that intensive natural gas development may 

increase the risk of adverse impact for some resources and thus those resources may require protections 

and mitigation beyond the Basic Protections. This alternative identifies the resources that may be more at 

risk from natural gas development and the Enhanced Resource Protections that would be implemented 

for these resources, which include enhanced protections and mitigation. 

The alternative also recognizes that future development may be more intensive than currently expected or 

may have unintended consequences, resulting in impacts on wildlife habitats and populations in areas that 

were not anticipated or impacts that occur at a faster pace than anticipated. For that reason, the alternative 

describes disturbance and population thresholds that, if crossed, would signal the need for still more 

protections and mitigation. The thresholds are described below and throughout the alternative description 

as Surface Disturbance Thresholds and Population Thresholds. 

The resources that would receive enhanced protection under this alternative are: 

 Mule deer crucial winter/yearlong range and migration corridors; 

 Pronghorn antelope crucial winter/yearlong range and migration corridors; 

 Greater sage-grouse lek, nesting/brood-rearing habitat, and winter concentration areas; 

 Ferruginous hawk nesting habitat; 

 The Muddy Creek and Bitter Creek corridors and watersheds; 

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CHAPTER 2—THE PROPOSED ACTION AND ALTERNATIVES
 

	 Chain Lakes alkaline wetland communities and other playas; and 

	 Livestock grazing. 

Basic Protections 

Most of the above resources already have protective measures specified in the RMP or applied as standard 

operating procedures. Such measures would apply to oil and gas operations within the CD-C project area 

under all alternatives. These Basic Protections are described below in each section for the resources 

receiving enhanced protections as a reminder that these requirements apply at all times regardless of 

alternative. For example, no activity is permitted within 0.25 mile of the perimeter of an occupied sagegrouse lek year-round. During the sage-grouse nesting/early brood-rearing season, March 1 – July 15, no 

activity is permitted within all identified sage-grouse habitat. Other RMP measures are provided in 

detailed guidelines for resource management such as those found in RMP Appendix 11 – Water Quality 

and Watershed Management. 

Standard operating procedures for resource protection can be found in Conditions of Approval (COAs) 

placed on an APD or in terms and conditions placed on a right-of-way grant (see Appendix C). In 

addition to items aimed at minimizing soil and water erosion and promoting successful reclamation, those 

measures may include such things as pre-disturbance surveys, consultation on facility location, signage, 

and constraints on traffic. 

Recently, interim conservation measures for sage-grouse have been proposed by Wyoming BLM 

Instruction Memorandum (IM) WY-2012-019 (February 10, 2012), which provides new statewide 

measures for protection of greater sage-grouse habitat. The IM provides interim program direction 

consistent with Washington Office IM No. 2012-043 until BLM Wyoming's effort to evaluate effective 

greater sage-grouse conservation measures through amendment of RMPs is completed. The protective 

measures identified in the IMs referenced above, or their functional equivalents, were analyzed within the 

range of alternatives. 

Enhanced Resource Protections 

Alternative B builds on the basic protections that are currently in effect in the project area, expanding the 

scale of some measures or adding new measures. An example of an expanded measure is increasing the 

avoidance zone around the Chain Lakes wetlands and other playas from 500 feet to 0.25 mile. Examples 

of new measures are burying new power lines within 1 mile of an occupied lek or in winter concentration 

areas, and extending the current monitoring program in Upper Muddy Creek to Lower Muddy Creek. 

Specific expanded resource protections are described for each of the high-value resources but several 

general protections apply to all. Three of these are: 

1.	 Uniform application of dust-abatement procedures during construction and drilling operations yearround and seasonally, as needed, on well sites, pipelines, and collector and well access roads. 

2.	 Environmental awareness training during orientation for all employees and subcontractors, 

including information about native wildlife, sensitivity to various kinds of impacts, Wyoming 

wildlife laws, etc. 

3.	 BLM will require remote monitoring at well pads when a surface disturbance threshold of 5 percent 

is reached for the resources that have that threshold. 

In addition, Applications for Permit to Drill (APDs) that would affect any of the described resources 

except livestock forage would be submitted with an overall development plan. The development plan 

would be submitted either for an individual lease or several leases. It should aim at reducing surface 

disturbance and disturbance associated with vehicle traffic and other human activity and should include, 

at a minimum: 

	 Consideration of cluster development of production facilities; 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 2-7 
 

 

CHAPTER 2—THE PROPOSED ACTION AND ALTERNATIVES
 

 A road system that minimizes construction of new roads; 

 Individual road design that minimizes surface disturbance while still meeting safe standards for the 

intended use; 

 Reconstruction of access roads to a lower standard once drilling is completed and the operation 

phase has begun; 

 Reclaiming of all but one road once production starts if more than one road is built within the lease; 

 A travel plan that minimizes vehicular traffic for monitoring and servicing wells and other facilities 

and that includes closures and/or time-of-day restrictions for production roads during the winter 

season; 

 Consideration of pipelines for transporting liquids offsite or installation of larger-capacity storage 

tanks to reduce the number of truck trips to well sites; and 

 A snow-removal plan to ensure protection of resources. 

Plans for development within the entire Muddy Creek and Bitter Creek watersheds should include, at a 

minimum, the following additional road/pipeline requirements: 

 Detailed development, transportation, and reclamation plans, including road design, culvert 

placement, steep slopes, etc.; 

 Design of improvements to existing roads or construction of new roads to minimize hydrologic 

alteration; 

 No new road crossings of Muddy Creek; 

 Development of specific road design criteria based upon site-specific review and likely including a 

combination of mitigation options; and 

	 Submission of data from inspections of erosion control BMP’s within the Muddy Creek and Bitter 

Creek watersheds would be required. The format and frequency of submission of these data would 

be coordinated with the BLM and could use the same information collected under the Stormwater 

Pollution Prevention Plan (SWPPP) or other BLM-approved monitoring method. 

Surface Disturbance Thresholds 

There may be instances in the future where natural gas development is even more intense locally than 

currently anticipated or where the overall impacts are greater than expected. In such cases, the Enhanced 

Resource Protection Alternative includes surface disturbance thresholds for five of the seven high-value 

resources: mule deer crucial winter/yearlong range and migration corridors; pronghorn antelope crucial 

winter/yearlong range and migration corridors; greater sage-grouse lek, nesting/brood-rearing habitat, and 

winter concentration areas; ferruginous hawk nests; and livestock grazing. 

Generally, two threshold levels are specified:3 

 A lower level, usually 5 percent of protected habitat within a lease and/or right-of-way, that signals 

a potential problem and mandates an evaluation of reclamation success. If reclamation success is 

limited, a revised plan would be required to address the failings. The initial level also calls for an 

assessment of the disturbance to determine if mitigation is needed. If it is, APDs will not be 

processed or approved until the BLM has received and approved a mitigation plan that will 

effectively mitigate the impact to the affected resource. 

3

 The 5% and 10% thresholds rely on WGFD guidance on mitigating oil and gas development and its references to High and 

Extreme impacts on habitat. High is generally referred to as 20-60 acres of disturbance within a section, and 5% is a proxy for that 

(640 acres X .05 = 32 acres); Extreme is 60 acres or more per section and 10% is a proxy for that (640 acres X .10 = 64 acres). 

Percentages have more utility than absolute figures when areas less than or larger than a section are under discussion. 

2-8 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
CHAPTER 2—THE PROPOSED ACTION AND ALTERNATIVES
 

	 A higher threshold level, usually 10 percent of protected habitat within a lease, would require
 

habitat improvement projects in addition to the above requirements. 

Disturbance that is counted against the threshold includes all disturbance, both current and pre-existing, 

that is associated with natural gas access roads, pipelines, well pads, or other facilities that serve the 

Operator’s lease and off-lease rights-of-way on adjacent BLM lands that also service the lease. Rights-ofway that cross a lease but service other Operators’ leases would not count in the percentage calculation. 

The details of the surface disturbance thresholds for each of the five resources are described in the 

sections below. 

Population Thresholds 

Additionally, there are population thresholds for four resources: mule deer crucial winter/yearlong range 

and migration corridors; pronghorn antelope crucial winter/yearlong range and migration corridors; 

greater sage-grouse lek, nesting/brood-rearing habitat, and winter concentration areas; and ferruginous 

hawk nests and potential nesting substrate. If the Wyoming Game and Fish Department (WGFD) were to 

express formal written concern that a species population within the project area were declining at an 

accelerated rate compared to the rest of the population, a technical team would be assembled to prepare a 

mitigation plan as described above. APDs would not be processed or approved until the BLM has 

received and approved a mitigation plan that will effectively mitigate the impact to the affected resource. 

The plan would include, but not be limited to: 

	 Evaluation of reclamation success and a request that the Operator provide a revised reclamation 

plan to address any failed reclamation. 

	 Implementation of BLM-approved habitat-improvement projects such as water developments or 

vegetation treatments. (The BLM may coordinate habitat improvement projects among multiple 

Operators.) New well pads would not be authorized without Operator participation in habitatimprovement projects. 

	 Limitation of the number of well pads per section to maintain habitat effectiveness. 

The preferred mitigation would be site-specific. If a species status were to change in the future, additional 

data, especially seasonal habitat use and condition data, would be collected and additional protective 

measures would be developed. 

2.2.3.1 Pronghorn Antelope and Mule Deer 

Area of Concern: Pronghorn Antelope Crucial Winter Range/Yearlong Range (referred to as “CWR” in 

the description of this alternative) and Migration Corridors (Map 3.8-2) and Mule Deer Crucial Winter 

and Crucial Winter/Yearlong Range (also referred to as “CWR”) and Migration Corridors (Map 3.8-4). 

Basic Protections: 

RMP Requirements 

 Seasonal restrictions on construction, drilling, and other activities from November 15 – April 30. 

 Disruptive activities within big game crucial winter range would require the use of BMPs designed 

to reduce the amount of human presence and activity during the winter months (Appendix 15 of the 

ROD). 

 Surface-disturbing and disruptive activities would be managed on a case-by-case basis in identified 

big game migration and transitional ranges to maintain their integrity and function. 

	 Fences identified to be a problem for big game migration would be modified to meet BLM fence 

standards. New fences would be allowed in big game migration corridors, provided they meet BLM 

fence standards. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 2-9 
CHAPTER 2—THE PROPOSED ACTION AND ALTERNATIVES
 

 Standard site-specific requirements 

 Appendix 15 of the RMP includes other BMPs that can be considered to reduce impacts from gas 

development, some of which are included as requirements in this alternative (e.g., remote well 

monitoring). 

Enhanced Resource Protections: 

 Applications for Permit to Drill (APDs) within mule deer or pronghorn antelope crucial winter or 

crucial winter/yearlong range and migration corridors would be submitted as part of an overall 

development plan for an entire lease or several leases. The plan is described above under the general 

requirements for the alternative. 

In addition, the following requirements would be implemented throughout mule deer and pronghorn 

antelope crucial winter range or crucial winter/yearlong range and migration corridors: 

 Man camps would be prohibited on BLM land; 

 Noise-reduction technology, such as hospital grade mufflers, sound walls or soundproof buildings, 

or adding silencers to cooling fans, would be required at compressor stations; and 

 Migration corridors would be monitored to determine which fences restrict movement and fences 

modified to reduce impacts to migrating big game species. 

Surface Disturbance Thresholds: 

When surface disturbance for natural gas access roads, pipelines, well pads or other facilities exceeds 5 

percent of pronghorn antelope or mule deer CWR and migration corridors within a lease, BLM would: 

	 Evaluate reclamation success in the lease and review, approve and oversee the implementation of an 

Operators’ revised reclamation plan to ensure it addresses the reason for the failed reclamation. The 

calculated percentage disturbance would be adjusted downward for successful interim reclamation. 

 Conduct an assessment of the disturbance and determine if enhancement of CWR is needed at this 

time. If so, begin implementation. 

 Require installation of remote monitoring at all well pads. 

If surface disturbance reached 10 percent of pronghorn or mule deer CWR and migration corridors in a 

lease, habitat improvement projects would be required in addition to the requirements above. The BLM 

would establish an interagency CD-C working group and consult with them to determine which projects 

would be beneficial. These projects could include, but would not be limited to: 

 Water developments. 

 Vegetation treatments such as herbicide treatments, seeding, prescribed burning, cutting/chopping 

for regeneration, planting shrubs or trees, fencing, establishing food plots, etc. 

Population Thresholds: 

Mule deer and pronghorn antelope in the project area are managed by the WGFD on a Herd Unit basis. 

Three mule deer Herd Units overlap the project area (Map 3.8-3). The resource of concern in this 

alternative for mule deer is CWR and migration corridors which only occur in the project area within the 

Baggs Herd Unit (Map 3.8-3). In 2010, the Baggs herd population was estimated at 22,000 animals, 

which is well above the WGFD population objective of 18,700 (Table 3.8-1). The project area includes 

less than 25 percent of the total Baggs Herd Unit acreage and only 6.3 percent of the crucial winter range 

and crucial winter/yearlong range. 

For pronghorn, there are also three Herd Units that overlap the project area (Map 3.8-1). The Baggs and 

Red Desert Herd Units each contain a portion of pronghorn CWR. Migration corridors are found in all 

three units. The Red Desert Herd Unit’s CWR lies north of I-80 along the majority of its route across the 

project area. The CWR for the Baggs and Bitter Creek Herd Units is adjacent to WY 789 in the 

southeastern portion of the project area (Map 3.8-1), overlapping the majority of the mule deer CWR. 

2-10 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
CHAPTER 2—THE PROPOSED ACTION AND ALTERNATIVES
 

Aerial surveys of the three Herd Units are done on a rotating basis, typically every two to three years. All 

three of the Herd Units are much larger than the portion within the project area; 26 percent of the Red 

Desert Herd Unit, 23 percent of the Bitter Creek Herd Unit, and 9 percent of the Baggs Herd Unit lie 

within the project area. Only 16 percent of the combined CWR for these Herd Units occurs in the CD-C 

project area. 

If the WGFD were to express formal written concern that any of the herds within the project area was 

declining at an accelerated rate, all new APDs on leases within mule deer and pronghorn antelope CWR 

in the CD-C project area would require an approved mitigation plan if the population decrease in those 

Herd Units were attributable in whole or in part to oil and gas development. The plan would include, but 

not be limited to: 

	 Evaluation of reclamation success in the lease and review, approve and oversee the implementation 

of an Operators’ revised reclamation plan to ensure it addresses the reason for the failed 

reclamation. 

	 Implementation of BLM-approved habitat-improvement projects such as water developments or 

vegetation treatments. (BLM may coordinate habitat improvement projects among multiple 

Operators.) New well pads would not be authorized without Operator participation in habitatimprovement projects in the affected Herd Unit. 

	 Limitation of the number of well pads to no more than four per section within CWR to maintain 

habitat effectiveness. 

If the population status of a species were to change in the future, additional data would be collected and 

additional protective measures would be developed. 

2.2.3.2 Greater Sage-Grouse 

Area of Concern: Greater sage-grouse lek, nesting/brood-rearing habitat (Map 3.9-2), and winter 

concentration areas occur throughout the project area. Protections for the small parts of the project area 

that are within sage-grouse core areas (Map 3.9-2), for which IM WY-2012-019 (February 10, 2012) 

prescribes more stringent protections, are described separately. In addition, the BLM has entered into an 

effort to revise all RMPs to address sage-grouse conservation efforts. As this process unfolds and the 

RFO RMP amendment is finalized, the requirements for sage-grouse conservation in the RFO may 

change from the current condition. The Wyoming Core Area strategy (SWED 2011) applies to all 

activities, proposed in a designated core area, that require a permit from any State of Wyoming regulatory 

agency. The Wyoming conservation strategy for greater sage-grouse continues to evolve and the 

requirements that would be applied to proposed activities in all seasonal sage-grouse habitats will change 

as the strategy changes. 

Basic Protections: 

	 RMP Requirements: 

o	 Surface-disturbing activities or occupancy are prohibited on and within 0.25 mile of the 

perimeter of an occupied (or undetermined) greater sage-grouse lek. In addition, disruptive 

activities are prohibited between 6:00 p.m. and 9:00 a.m. from March 1 to May 20 on and 

within 0.25 mile of the perimeter of an occupied greater sage-grouse lek. (Disruptive activities 

are those that would require people and/or the activity to be in nesting habitats for a duration of 

1 hour or more during a 24-hour period.[IM WY-2010-029]) 

o	 Avoid surface-disturbing and/or disruptive activities in all identified nesting and early broodrearing habitat from March 1 to July 15. 

o	 Authorization of high-profile structures would be granted on a case-by-case basis from within 

0.25 to 1 mile of the perimeter of an occupied sage-grouse lek. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 2-11 
 

 

 

CHAPTER 2—THE PROPOSED ACTION AND ALTERNATIVES
 

o Surface disturbing and other activities potentially disruptive to delineated greater sage-grouse 

winter concentration areas are prohibited during the period of November 15 to March 14. 

	 IM WY-2012-019 Requirements summarized: 

o	 West Nile Virus - Artificial water impoundments would be managed to the extent of BLM’s 

authority to prevent the spread of West Nile virus where the virus poses a threat to sage-grouse. 

(See specific provisions in the IM.) 

o	 Timing and Distance Restrictions Within Core Areas 

- Surface occupancy and/or disruptive activities are prohibited on or within 0.6 mile of the 

perimeter of occupied sage-grouse leks. 

- Surface-disturbing and/or disruptive activities are prohibited or restricted from March 15 to 

June 304

 within all suitable sage-grouse nesting and early brood-rearing habitat. 

- Surface-disturbing and/or disruptive activities in delineated sage-grouse winter 

concentration areas are prohibited from December 1 to March 14 to protect core 

populations of sage-grouse that use these winter concentration habitats. Not all these 

WCAs that support core area populations, are located within current core area boundaries. 

o	 Timing and Distance Restrictions Outside Core Areas 

- Surface occupancy and/or disruptive activities are prohibited on or within a 0.25 mile 

radius of the perimeter of occupied sage-grouse leks. 

o	 Density and Disturbance Within Core Areas 

- For authorization of new proposed actions within sage-grouse core areas, including where 

there are valid existing rights, the BLM will consider an alternative that would limit 

activities to an average of no more than one oil and gas or mining location per 640 acres 

and an average of no more than 5 percent habitat disturbance (related to all programs or 

applicable sources of “disturbance” using the SGEO [Greater Sage-grouse Core Area 

Protection Program] Disturbance Density Calculation Tool). In addition, the BLM has 

entered into an effort to revise all RMPs to address sage-grouse conservation efforts. As 

this process unfolds and the RFO RMP amendment is finalized, the requirements for sagegrouse conservation in the RFO will change from the current condition. 

	 Noise – The BLM will work with Operators to limit noise where it could reduce functionality of 

habitats that support core area populations. The BLM will evaluate limitation of new noise sources 

on a case-by-case basis. The BLM’s near-term goal is to limit noise sources that would negatively 

impact core area sage-grouse populations and to support the establishment of ambient baseline noise 

levels for occupied core area leks. 

	 Standard site-specific requirements – Appendix 15 of the RMP includes other BMPs that can be 

considered to reduce impacts from gas development, some of which are included as requirements in 

this alternative, e.g., remote well monitoring. 

Enhanced Resource Protections: 

Applications for Permit to Drill (APDs) within greater sage-grouse lek, nesting/brood-rearing habitat, and 

winter concentration areas would be submitted as part of an overall development plan for an entire lease 

or several leases. The plan is described previously in the general requirements portion of the alternative. 

In addition, the following requirements would be implemented throughout sage-grouse habitat: 

4

 IM WY-2012-019 allows for the Governor’s Executive Order Timing Restriction (March 15-June 30) to be expanded by up to 14 

days prior to or subsequent to these dates where credible data support different timeframes. 

2-12 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
CHAPTER 2—THE PROPOSED ACTION AND ALTERNATIVES
 

 Burying new power lines and using low-profile facilities within 1 mile of an occupied lek or in 

winter concentration areas; 

 Use of noise-reduction technology so that noise would not exceed 49 decibels measured at 30 feet 

from the source at all drilling, production and compressor sites; 

 No more than one oil and gas or mining location per 640 acres and no more than 5 percent habitat 

disturbance (related to all programs or applicable sources of disturbance). 

 Surface Disturbance Thresholds: 

The BLM has authority to apply a number of protective measures to minimize impacts upon sage-grouse 

and their habitat. This surface disturbance threshold requires that certain of those measures go into effect 

on a lease if surface disturbance for natural gas roads, pipelines, well pads or other facilities has exceeded 

5 percent of non-core sage-grouse lek, nesting/early brood-rearing habitat, or winter concentration areas 

in a lease or right-of-way or one oil and gas or mining location per 640 acres within core areas, the BLM 

would: 

 Require remote well-monitoring at all well pads; 

 Evaluate reclamation success in the section and request from the Operator a revised reclamation 

plan to address any failed reclamation. The calculated percentage disturbance would be adjusted 

downward for successful interim reclamation. 

 Conduct an assessment of the disturbance and determine if enhancement of sage-grouse habitat is 

needed at that time. If so, begin implementation. 

If surface disturbance were to reach 10 percent or 2 oil and gas or mining locations per 640 acres of 

non-core sage-grouse lek, nesting/early brood-rearing habitat, or winter concentration areas in a lease, 

habitat improvement projects would be required. Projects could include, but would not be limited to: 

 Vegetation treatments such as fertilization, seeding, prescribed burning, cutting/chopping for 

regeneration, planting shrubs, establishment of food plots, etc. 

 Water developments.
 

Population Thresholds: 

If WGFD were to express formal written concern that the population of sage-grouse is declining at an 

accelerated rate, all Operators on public lands within sage-grouse lek, nesting/early brood-rearing habitat 

or winter concentration areas would implement a mitigation package identified by BLM that would 

include, but not be limited to: 

	 Evaluation of reclamation success in the lease or right-of-way and a request to the Operator to 

provide a revised reclamation plan to address any failed reclamation. 

	 Vegetation treatments such as fertilization, seeding, prescribed burning, cutting/chopping for 

regeneration, planting shrubs, establishment of food plots, etc. (BLM may also coordinate habitat 

improvement projects among multiple Operators.) 

 Timing and Distance Restrictions (Non-core areas to conform with core areas): 

 When the threshold is reached, surface-disturbing activity or surface occupancy would be prohibited 

or restricted on or within a 0.6 mile of the perimeter of occupied sage-grouse leks. In addition, 

disruptive activities within 0.6 mile of the perimeter of occupied sage-grouse leks are restricted 

from 6:00 pm to 9:00 am from March 1 – May 15. 

 Avoid surface-disturbing and disruptive activities in suitable greater sage-grouse nesting and early 

brood-rearing habitat within 2.5 miles of the perimeter of an occupied lek from March 15 – June 30. 

 Prohibition of surface-disturbing and disruptive activities within 0.5 mile of sage-grouse winter 

concentration areas (non-core areas) from November 15 – March 14. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 2-13 
CHAPTER 2—THE PROPOSED ACTION AND ALTERNATIVES
 

Density Restrictions: 

	 Core Area APDs would be limited to the density disturbance calculation tool thresholds (see density 

restrictions in IM 2012-019). When thresholds are exceeded BLM would work to collocate or 

minimize disturbance for valid and existing rights. 

 When the population threshold is reached in non-core areas, strive to maintain <3 pads per square 

mile within 2 miles of the perimeter of occupied sage-grouse leks 

 If the population status of the species changes in the future, additional data would be collected and 

additional protection measures would be developed. 

2.2.3.3 Ferruginous Hawks 

Area of Concern: Nests and potential nesting substrate (Map 3.8-8) 

Basic Protections: 

	 RMP Requirements: 

o	 No disturbance within 1,200 feet of a ferruginous hawk nest. The distances could vary 

depending on factors such as nest activity, species, natural topographic barriers and line-of-sight 

distances. 

o Seasonal restriction from March 1 – July 31 within 1 mile of a ferruginous hawk nest. 

 Standard site-specific requirements:
 

o	 Surveys of previous active ferruginous hawk nests to determine if they are in use that season. 

Lack of occupancy by a certain date could shorten the seasonal restriction. 

o	 If drilling activity within the seasonal distance restriction were started prior to the nesting period 

and a ferruginous hawk started utilizing a nest, additional mitigation as determined by the BLM 

could be required. This mitigation could include, but would not be limited to: 

- education sessions for employees regarding avoidance of the nest; 

- reducing speeds and being aware of foraging raptors; 

- utilization of alternate access routes to the well that are further away from the nest, etc. 

Enhanced Resource Alternative Protections: 

No additional protections would apply to ferruginous hawk nests and potential nesting substrate unless 

one of the thresholds described below were reached. 

Surface Disturbance Threshold: 

Operators in all leases that exceed 10 percent of surface disturbance within 1 mile of ferruginous hawk 

nests would be required to participate in a development/mitigation plan before additional APDs would be 

issued. 

Population Thresholds: 

If WGFD were to express formal written concern about the ferruginous hawk population, the following 

mitigation measures would be implemented immediately: 

1.	 All existing development features and facilities (pads, pipelines, roads, holding yards, compressor 

stations, etc.) within 1 mile of ferruginous hawk nests would be inspected to determine 

reclamation success. If reclamation has been unsuccessful, measures would be taken to improve the 

reclamation of the facilities. 

2-14 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
 

CHAPTER 2—THE PROPOSED ACTION AND ALTERNATIVES
 

2.	 Ten man-made5 nests would be built outside of existing monitoring territories on natural substrates, 

and farther than 1,200 feet from existing disturbances, prior to January 10th of the year following 

receipt of WGFD’s letter of concern. 

a. The farther the nest is constructed from existing disturbances the better; nest placement would 

take into consideration potential conflicts with sage-grouse seasonal habitat use of the area. 

b.	 These nests would be incorporated into the annual monitoring efforts. 

c.	 Controlled Surface Use and Timing Limitation stipulations would be applied to any nests that 

become occupied by raptors. 

3.	 Two artificial nesting structures 6

 would be placed outside of existing monitoring territories, and 

farther than 1,200 feet from existing disturbances, prior to January 10th of the year following. receipt 

of WGFD’s letter of concern. 

a.	 Priority for placement of these nests would be determined based on information regarding 

extant nests located on man-made infrastructure, or where there are known repeated attempts at 

nesting on man-made infrastructure; nest placement would take into consideration potential 

conflicts with sage-grouse seasonal habitat use of the area. 

b.	 These nests would be incorporated into the annual monitoring efforts. 

c.	 Controlled Surface Use and Timing Limitation stipulations would be applied to any nests that 

become occupied by raptors. 

If the species population continues to decline, additional data would be collected and additional protection 

measures would be developed. 

2.2.3.4 Muddy Creek and Bitter Creek Corridors/Watersheds 

Area of Concern: Muddy Creek (including the Red Wash/Muddy Creek Sensitive Fish Habitat), and the 

Muddy Creek and Bitter Creek watersheds for water quality (salinity, selenium, and 303d listed waters), 

aquatic physical habitats, and sensitive fish habitat (Map 3.9-5). 

Basic Protections: 

	 RMP Requirements: 

o	 For protection of amphibians and their habitats, avoidance of surface-disturbing and disruptive 

activities within 500 feet of perennial waters, springs, wells and wetlands, and areas within 100 

feet of the inner gorge of ephemeral channels. 

o	 Design of road crossings of water bodies that potentially support fish for a portion of the year to 

simulate natural stream processes. 

o	 Design of impoundments and instream structures to minimize impacts on Special Status fish 

species and their habitats. 

o	 Intensive management of surface-disturbing activities within those portions of the Muddy Creek 

drainage that contribute to degradation of reaches previously or currently on the 303d list. 

o	 All basic watershed protections in Section 2.3.16, Water Quality, Watershed, and Soils 

Management, and Appendix 13, Reducing Nonpoint Source Pollution with Best Management 

Practices, of the RMP ROD. 

	 Standard site-specific requirements: 

5

 Man-made nests are nests that are built in appropriate habitat and are intended to attract ferruginous hawks. 

6

 Artificial nesting structures are built to attract hawks that would build their own nest on the structure. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 2-15 
 

CHAPTER 2—THE PROPOSED ACTION AND ALTERNATIVES
 

o	 Maintenance of existing roads to ensure they are not contributing sediment to Muddy Creek or 

adjacent wetlands. 

o	 Boring of all pipeline crossings of riparian areas. 

o	 Appendices 13 and 15 of the RMP include several BMPs that can be considered to reduce 

impacts from gas development, a number of which are included as requirements in this 

alternative. 

Enhanced Resource Alternative Protections: 

	 For protection of amphibians and their habitats, avoidance of surface-disturbing and disruptive 

activities within 0.25 mile of Red Wash, springs, wells, and wetlands. The required avoidance 

distance would be further increased on perennial streams to 0.5 mile. Exceptions would only be 

granted by the BLM based on environmental analysis and site-specific engineering and mitigation 

plans. Only actions within areas that could not be avoided and that would provide protection for the 

resource identified would be approved. In-channel activities would be restricted to the low-flow 

period. 

	 Current monitoring on upper Muddy Creek would be extended to Lower Muddy Creek in the CD-C 

area. This requirement would bring lower Muddy Creek into conformance with the monitoring 

being done for upper Muddy Creek and other drainages within the Atlantic Rim project area. If 

results of the monitoring program showed impacts to sensitive fish habitat, the BLM and an 

interagency CD-C consultation group would determine whether habitat-improvement projects 

should be implemented. The projects could include, but would not be limited to: increasing the 

number of drainage features along roads, increasing in-stream cover for fish, etc. 

 A monitoring plan for Bitter Creek watershed will be designed by the RFO. 

 A risk level analysis will be conducted for the Muddy Creek and Bitter Creek watersheds using the 

existing Rosgen 2008 WARSS process and data to determine the risk of additional sedimentation. 

This will permit identification of areas of high erosion potential. 

The following requirements related to selenium and salinity for well locations and operations would also 

be implemented: 

 No surface discharge of produced waters within the Muddy Creek and Bitter Creek watersheds. 

 Line all reserve pits in the Muddy Creek and Bitter Creek watersheds with BLM-approved 

materials. 

2.2.3.5 Chain Lakes Alkaline Wetland Communities and Other Playas 

Area of Concern: Chain Lakes Alkaline Wetlands and other playas 

Basic Protections: 

	 RMP Requirements – For protection of amphibians and their habitats, avoidance of surfacedisturbing and disruptive activities within 500 feet of perennial waters, springs, wells, and wetlands 

(defined here as 500 feet from the ordinary high water mark of the playa). 

	 Standard site-specific requirements – None 

Enhanced Resource Alternative Protections: 

 A transportation and development plan to avoid the alkaline wetland communities at Chain Lakes. 

 Avoidance of surface-disturbing and disruptive activities within 0.25 mile of any Chain Lakes 

alkaline wetland community or the ordinary high water mark of other playas. 

2-16 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
CHAPTER 2—THE PROPOSED ACTION AND ALTERNATIVES
 

2.2.3.6 Livestock Grazing 

Area of Concern: Public land grazing allotments (Map 3.18-1) 

Basic Protections: 

 RMP Requirements – Wyoming Standards and Guidelines for Rangeland Health. 

 Standard site-specific requirements – Immediate repair of any damages to existing range 

improvements, fences, cattleguards, gates, etc. caused by natural-gas operations, with such repairs 

to be made by the natural-gas Operators in consultation with the grazing permittee. 

Enhanced Resource Alternative Protections: 

	 Mitigation of impacts on existing livestock water features such that there would be no adverse 

effects on water availability, water quality, or livestock management (trailing routes, fencing, etc.); 

mitigation of impacts on water wells, springs, or surface water improvements by new water well 

development. If water features are adversely affected by activities of natural gas Operators, the 

Operators would be responsible for drilling, maintaining, and monitoring new stock water wells 

and/or improving existing water wells, as determined by BLM and the grazing permittees. 

	 Annual meetings conducted by BLM with Operators and grazing permittees to discuss projectspecific impacts and required mitigation. Natural gas Operators will describe their proposed drilling 

and maintenance schedules during these meetings. 

 When APDs are submitted to BLM, notification of the affected grazing permittees and provision to 

permittees of a map showing the location of new well pads and access roads. 

 Thorough power-washing by Operators of all field vehicles—particularly their undercarriages— 

before entering the project area or when moving from one part of the project area to another. 

 During the production phase, as well as the construction phase, control by Operators of fugitive dust 

on well sites, pipelines, and access roads as needed. 

Surface Disturbance Thresholds: 

If the surface disturbance due to natural gas development were to reach 5 percent of an allotment, several 

actions would be triggered (in this and later calculations, surface disturbance is used as a surrogate for 

available forage): 

	 A review of reclamation success in the allotment. If reclamation efforts had not achieved the 

required standards, Operators would be required to submit a revised reclamation plan for achieving 

reclamation success and begin implementing that plan. 

	 Planning for future natural gas development to avoid critical grazing areas (i.e. calving grounds, 

trailing routes, and identified summer and winter grounds), range improvements, and other 

important livestock areas. 

	 If planning were to identify the need for rangeland improvement projects, BLM would begin 

planning such projects in consultation with the grazing permittee and the Operators, and may begin 

implementing the projects, as warranted. Rangeland improvement projects with allotment-wide 

benefits could involve participation of all Operators within the allotment. 

If the amount of unreclaimed surface disturbance due to natural gas development were to reach 8 percent 

of an allotment, the BLM would require that mitigation be implemented to avoid reaching the designated 

RMP significance criterion of a permanent 10-percent reduction in AUMs available for livestock grazing 

within the allotment. The type of mitigation would be determined by the BLM in concert with the grazing 

permittee and could include, but would not be limited to, the following: 

	 Construction of temporary fencing when necessary in order to protect reseeded areas and other 

fragile areas.
 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 2-17 
 

CHAPTER 2—THE PROPOSED ACTION AND ALTERNATIVES
 

	 Construction of temporary or permanent fences to create pastures to improve livestock distribution 

and/or minimize livestock and vehicle collisions (all fences would comply with BLM fence 

construction regulations). 

	 Water development projects to distribute livestock, when consistent with the RMP. 

	 Vegetation treatment projects to increase and improve forage for livestock. 

2.2.4 Alternative C: Surface Disturbance Cap—High and Low Density Development 

Areas 

This alternative designates parts of the project area as high-density development areas—those areas that 

have seen the greatest natural gas development to date (Map 2-1). Within the high-density development 

areas, a 60-acre cap would be placed on the amount of unreclaimed surface disturbance at any one time in 

a section of public land or federal mineral estate. For the remainder of the project area—the low-density 

development areas—the cap would be 30 acres per section. The 60-acre cap represents the disturbance 

associated with a 9-well per section drilling program (80-acre spacing) achieved with vertical wells only, 

a typical development in the high-density area; a 30-acre cap represents the disturbance associated with a 

16-well per section drilling program (40-acre spacing) achieved with directional drilling. 

All prior surface disturbance committed to long-term use for roads or on-pad production facilities and all 

disturbance that had not been successfully reclaimed would count against the cap. Acreage that had 

successfully undergone interim reclamation would not count against the cap. For example, within a highdensity development area, a section that had seen 40 acres of historical disturbance for natural gas 

development would start the development period with a reduced cap of 20 acres (60 acres less 40). Once 

interim reclamation on the development was determined to be successful, the acreage reclaimed could be 

rolled over, meaning counted again as undisturbed acreage, and the cap would be increased by the amount 

of successful interim reclamation. If, for example, 24 acres of interim reclamation were judged to meet 

the interim reclamation standard, it would be rolled over and the cap for that section would increase to 44 

acres (20 acres plus 24). Only the 16 acres used for roads and production facilities would continue to 

count against the cap. 

If there had been no natural gas development in a section within the high-density development area, the 

Operator would be able to develop the natural gas resources of that section until surface disturbance from 

well pad, access road, and pipeline construction reached 60 acres. At that point, no further disturbance 

could take place until acreage that had undergone interim reclamation had been determined to be 

successfully reclaimed. Outside the high-density development areas, the same conditions and the same 

process would apply, but the cap would be set at 30 acres. 

Map 2-1 shows the high-density development and low-density development areas within the project area. 

Of the 1,697 sections within the project area, 744 sections (about 44 percent) are within a high-density 

development area. Average historic surface disturbance within the high-density development areas is 32.9 

acres per section. The average number of wells per section is 5.1. Outside the high-density development 

areas, the average disturbance is 4.5 acres per section; the average number of wells per section is 0.7. 

Four hundred sections, about 24 percent, have had no development to date. 

All public lands in the project area would be subject to the cap. Disturbance on private and state lands 

would not count against the cap. The Operators would be required to update their reported disturbance 

annually in order to certify the accumulated disturbance on their federal lease holdings to date and the 

amount of interim reclamation that had occurred. Under the alternative, the BLM, either on its own or 

using subcontractors hired by the Operators, would perform quality control on the reported data and 

evaluate the reported interim reclamation and the success of that reclamation. The BLM would then 

calculate net available surface disturbance under the cap for each section. As new drilling proposals were 

received, they would be evaluated against the net available surface disturbance within the section where 

2-18 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
CHAPTER 2—THE PROPOSED ACTION AND ALTERNATIVES
 

the drilling was proposed. For oil and gas leases smaller than a section, the acreage cap would be adjusted 

on a pro-rata basis. 

All pre-existing and current surface disturbance associated with natural gas well pads, their access roads, 

and gathering pipelines would count against the cap. Major natural gas processing and transmission 

facilities would not count against the cap. In addition, federal, state, county, and local roads and 

highways, railroads, and disturbances created by ranching operations would not count against the cap. 

A central element of this alternative is the standard used to determine if interim reclamation efforts have 

been successful and if the reclaimed acreage can be rolled over. The standards to be met for successful 

final reclamation of surface disturbance on public lands are described in Appendix E: Reclamation, 

which includes Appendix 36 of the Rawlins RMP (BLM 2008b) and the Wyoming BLM Reclamation 

Policy IM WY-2012-032. Final reclamation of a natural gas well site occurs after a well has completed 

production and been plugged and abandoned. Appendix E also includes two other documents that apply 

to interim reclamation and the concept of rollover: the Proposed Interim Rollover Objective for the CD-C 

Natural Gas Project and the CD-C Rollover Criteria. These two documents would guide the evaluation of 

reclamation under the Alternative C surface cap and set the standard for potential rollover of acreage that 

had undergone interim reclamation. The Rollover Objective document provides guidance for how best to 

achieve interim reclamation that can be rolled over. The CD-C Rollover Criteria document lays out the 

standard that must be met if disturbed acreage is to be classified as successful interim reclamation. 

Disturbed acreage that met the standards could then be deducted from the number of acres counted as 

surface disturbance—that is, rolled over. 

During the preparation of the Draft EIS, the State of Wyoming, local Conservation Districts, the 

University of Wyoming, participating leaseholders, several CD-C operators, and the BLM developed 

interim reclamation objectives (IRO). The purpose of the IRO is to identify when reconstruction and revegetation activities on disturbed lands are adequate for rollover credit. The objectives are to: establish 

vegetation cover sufficient to maintain a healthy, biologically active topsoil; control erosion; minimize 

loss of habitat, forage, and visual resources during the period of the disturbance; and control invasive nonnative weeds. The specific reclamation success standards for the IRO are as follows: 

 The area is revegetated with a stable, approved plant community. 

 Vegetative cover is sufficient to maintain a healthy, biologically active topsoil. 

 Erosion is controlled. 

 Habitat, visual, and forage loss is minimized. 

 No noxious weeds are present. 

Reclamation of the disturbed surface would be monitored by the Operators. When an operator determined 

that a disturbed site had attained the IRO, the operator would propose to the BLM the rollover of the 

reclaimed acreage. If the BLM determined that the standards had been met, the acreage would be rolled 

over. If the BLM determined that the standard had not been met, then the operator could attempt to 

address the shortcomings of the reclamation and propose the acreage again at some time in the future. In 

the event areas that had met the criteria and been rolled over were re-disturbed, the acreage re-disturbed 

would again be counted against the cap. 

Table 2.4-1 shows the estimated surface disturbance for this alternative along with the Proposed Action 

and the other alternatives. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 2-19 
CHAPTER 2—THE PROPOSED ACTION AND ALTERNATIVES
 

Map 2-1. High-density and low-density natural gas development areas, CD-C project area 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

2-20 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
 

 

CHAPTER 2—THE PROPOSED ACTION AND ALTERNATIVES
 

2.2.5 Alternative D: Directional Drilling 

This alternative requires that all future natural gas wells on federal mineral estate be drilled from multiwell pads, which would require the employment of directional drilling technology. One new multi-well 

pad per section (or per lease if the lease area is less than a section) would be permitted. In sections that 

have already had oil and gas development, the enlargement of one existing well pad would be permitted 

as the multi-well pad for all future drilling in that section. No new roads or pipeline routes on a lease 

would be permitted. Proposals for access across federal lands for oil and gas development on adjacent 

private and state parcels would still be considered as appropriate by the BLM. 

In sections that have not had oil and gas development at all, one new well pad would be permitted for all 

future development. One road and pipeline corridor per well would be permitted. Proposals for access 

across federal lands for oil and gas development on adjacent private and state parcels would still be 

considered as appropriate by the BLM. No numerical disturbance caps, no rollover credits, and no new 

requirements on reclamation are part of this alternative. 

The objective of this alternative is to minimize surface disturbance and to reduce habitat loss and wildlife 

disruption. A reduction in the number of well pads and associated roads, pipelines, and other facilities 

would result in less surface disturbance and thus reduce the amount of habitat directly lost. In addition, 

multiple-well pads would be distributed less densely than single-well pads, reducing the habitat 

fragmentation and ongoing disturbance created by the network of well-pad access roads. 

Operators may request that an APD be excepted from the general rule. Examples of the types of 

exceptions that would be considered include: 

	 In sections that have already had some level of development, Operators may request that more than 

one existing well pad be used as a multi-well pad. The Operator must establish that the drilling 

objective cannot be achieved from any single well pad. In general, such requests would be 

considered by BLM after one single-well pad had been enlarged and efforts had been made to 

develop the entire section. 

	 In sections that have not had prior development, Operators may request that more than one multiwell pad be constructed. The Operator must establish that the drilling objective cannot be achieved 

from a single-well pad. In general, such requests would be considered by BLM after one multi-well 

pad had been constructed and efforts had been made to develop the entire section. 

	 Operators may request that road and pipeline routes be relocated. The request should demonstrate 

how the relocation would reduce vehicle traffic and increase the efficiency of product 

transportation. 

It is expected that exception requests would largely be based on difficult surface conditions, topography, 

subsurface geology, or fluid mineral resource characteristics that would make it impossible to maximize 

the recovery of the gas resource in a lease. CBM proposals may well fall into an exception category. 

Requests based on the need to produce in the most economic and efficient manner will be considered. 

Table 2.4-1 shows the estimated surface disturbance for this alternative along with the Proposed Action 

and the other alternatives. 

2.2.6 Alternative E: No Action 

NEPA regulations require that the EIS alternatives analysis “include the alternative of no action” (40 

Code of Federal Regulations [CFR] 1502.14(d)). The No Action alternative does not respond to the 

purpose and need for the Proposed Action. Rather, it serves as a baseline for comparing the Proposed 

Action’s environmental effects (including cumulative effects) and it illustrates the consequences of not 

meeting the need for the Proposed Action. Under the No Action alternative, no new Federal wells would 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 2-21 
CHAPTER 2—THE PROPOSED ACTION AND ALTERNATIVES
 

be approved for development as part of the Operators’ proposal to drill up to 8,950 wells on 

approximately 1.1 million acres of federal, private, and state mineral estate. However, existing lease 

rights granted by the BLM on federal lands or mineral estate would remain in effect. The BLM’s analysis 

of the No Action alternative therefore assumes that previously authorized activities would continue but 

that no new development on federal lands or mineral estate would occur under the Operators’ 

proposal. Previously authorized activities include approximately 14 pending APDs, 497 shut-in gas wells, 

12 monitor wells, 530 plugged and abandoned wells, 3,292 producing gas wells, and 27 unapproved 

APDs, totaling 4,372 wells within the CD-C project boundary as of September 2012 (WOGGC 2012). As 

shown on Table 4.0-1, existing surface disturbance related to natural gas development is an estimated 

49,218 acres. 

Due to the intermingling of federal, state, and private lands within the CD-C, rejection of the Operators’ 

proposal under the No Action alternative would not mean that no new oil and gas development in the 

project area would occur. Such development may be authorized on state and private lands, as the BLM 

does not approve or control development on these lands. In addition, the BLM may receive and consider 

proposals for access across federal lands for oil and gas development and production-related activities. 

The BLM also may receive and consider additional or supplemental proposals (such as pipelines, 

compressors, and power lines) to develop leased resources, such as natural gas, on federal lands in the 

project area. Individual proposals for geophysical exploration or development, including rights-of-way for 

access across federal lands, would be subject to site-specific analysis prior to approval or authorization by 

the BLM. 

2.3 ALTERNATIVES CONSIDERED AND ELIMINATED FROM DETAILED STUDY 

Two alternatives were considered and eliminated from detailed study. The alternatives and the reasons for 

eliminating them are described below. 

2.3.1 Surface Disturbance Cap with Reclamation Credits and Debits 

This alternative would place a 30-acre cap on the amount of future surface disturbance in a section of 

public land. If previous natural gas development had disturbed the surface in a section, the acreage that 

had been successfully reclaimed would be added to the 30 acres. If the disturbance had not been 

successfully reclaimed, the acreage would be subtracted from 30 acres. The aim is to provide additional 

incentive for successful reclamation and increased disincentive for slow or failed reclamation. For 

example, in a section in which 10 acres of surface disturbance had occurred and 6 acres had been 

reclaimed, the cap would be modified according to the success or failure of the reclamation on those 6 

acres. (The 4 acres used for roads and on-pad facilities would not count one way or the other toward 

credits or debits, but would count against the cap.) If the 6 acres met the criteria for successful 

reclamation, the modified cap for that section would be 30 acres plus the 6 acres of reclaimed surface, a 

total cap of 36 acres (of which 4 had been used for roads and on-pad facilities, leaving 32 acres that could 

still be utilized). If, on the other hand, the 6 acres did not satisfy the criteria, the modified cap would be 

24 acres—the 30-acre base less the 6 acres of unsuccessful reclamation (4 of which were already 

impacted, leaving 20 acres for future development). If half the reclamation met the criteria and half did 

not, the 30-acre cap would remain unchanged, as the failed 3 acres would offset the successful 3 acres, 

leaving the cap at 30 acres with 4 of those acres encumbered. 

After closely considering this alternative, the BLM determined its actual operation would be 

unpredictable and that neither the BLM nor the Operators could rely on its results. In certain instances, 

the formulation could yield a cap in one section of perhaps 90 acres and in an adjacent section of minus 

30 acres. The complexity of the alternative and the uncertainty of its results make it difficult to describe 

and there is a high likelihood that the result would be contention between the BLM and the Operators 

over the meaning of and the operation of the cap. Because of the complexity and the uncertainty about its 

2-22 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
CHAPTER 2—THE PROPOSED ACTION AND ALTERNATIVES
 

effects, and because Alternative C already satisfied all the criteria for a surface disturbance cap, the BLM 

decided that the Surface Disturbance Cap with Reclamation Credits and Debits would not be carried 

forward for analysis in the EIS. 

2.3.2 Focused Development 

The Focused Development Alternative would include the same degree of overall natural gas development 

as the Proposed Action, but the drilling would be phased geographically, focusing first on one defined 

area and then moving to another area following completion of development in the initial area. The 

purpose of the geographical phasing would be to allow large areas of wildlife habitat to remain 

undisturbed for an extended period, during which other areas would undergo intense and continuous 

development. Several alternatives with this general formulation were considered during discussions 

between the Operators and the CD-C cooperating agencies between 2005 and 2009. The BLM was not a 

participant in those discussions. Discussions were aimed at identifying larger tracts of habitat that could 

remain undeveloped for a considerable period of time and other areas―areas of focused 

development―that would be completely developed during that same period. In exchange for agreeing to 

delay developing in one area, the Operators would receive exemption from seasonal wildlife stipulations 

on public lands in the area of focused development. Upon completion of development in the initial focus 

area, that area would in turn have no activity and development would shift to the previously undeveloped 

area. 

The concept of focused development has two key elements: (1) that the leaseholders, property owners, 

Operators, and others with an interest in the production of oil and gas in both the area of focused 

development and those in the area of delayed development area be the same or at least have a shared 

interest, since all the parties would have to participate if the concept were to be effective; and (2) that the 

BLM would be able to exempt the federal oil and gas leaseholders from the seasonal wildlife stipulations. 

After considerable examination, it was determined that neither of the key elements could be provided. 

In the case of developing a shared interest among those interested in developing the fluid mineral estate, 

the sheer number of interests (over 60 different leaseholders within the project area and over 20 different 

operators), and the diversity and complexity of their holdings presented legal, planning, and logistical 

problems that could not be overcome. Additionally, the substantial portion of the project area that is 

within the checkerboard would require participation by private property owners, many of whom are not 

federal leaseholders. 

The creation of an oil and gas unit is one method of creating a shared interest among various parties. A 

unit agreement allows exploration and development of properties owned by multiple parties to proceed 

with a program paced to develop all lands within the unit, regardless of ownership boundaries. Unitizing 

the CD-C project area to create a shared interest would not work because: (1) The leaseholders, property 

owners, operators, and operating rights owners over such a wide geographical area—the whole project 

area or a large part of it—do not have sufficient interests in common for a single exploratory unit to be 

formed; (2) Developing exploration units requires certain levels of obligation to drill wells. Under the 

Yates decision, if the drilling is successful and yields a producing well, all leases covered by the unit are 

considered held by production (Yates Petroleum Corp. et al., 67 IBLA 246, 1982). Holding hundreds of 

thousands of leasehold acreage without development is not in the best interest of the BLM as the federal 

lessor; and (3) Leases are offered and granted with certain time terms, during which leaseholders and 

Operators are obligated to develop the leases or the leases will expire. If a CD-C project unit were to 

form, then hundreds of thousands of leased acres could be held by production from only a few wells and 

the owners of these leases likely would not receive the returns needed to pay out the cost of acquiring the 

leases. This in turn could result in the operator not being able to drill and produce at adequate levels to 

meet their income requirements or returns on investment. This would be a major impact to stockholder 

value and the development of U.S. energy. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 2-23 
 

 

CHAPTER 2—THE PROPOSED ACTION AND ALTERNATIVES
 

It was also determined that exempting the leaseholders from seasonal wildlife stipulations could not be 

done. The BLM reviewed the federal laws and regulations that govern the management of habitat of 

species protected under the ESA and those that were designated as Special Status by the BLM and 

concluded it could not agree to the necessary blanket exemptions, over such a large area, for such an 

extended period of time. With no ability to bring about either of the key elements of the Focused 

Development alternative, the participants in the discussion concluded that such an alternative could not be 

properly designed and implemented. 

2.4 COMPARISON OF ALTERNATIVES 

Table 2.4-1. CD-C project area disturbance: Proposed Action and alternatives (acres) 

Category 

Well Pads (incl. 

roads) 

Related O&G 

Facilities 

Total Disturbed 

Area Change from Proposed Action 

acres acres % 

Proposed Action 

Initial 41,889 5,311 47,200 — — 

Long-term 17,998 863 18,861 — — 

Alternative A: 100-Percent Vertical Drilling 

Initial 56,385 5,311 61,696 14,496 30.7% 

Long-term 23,270 863 24,133 5,272 28.0% 

Alternative B: Enhanced Resource Protection 

Initial 40,205 5,311 45,516 -1,684 -3.6% 

Long-term 17,386 863 18,249 -611 -3.2% 

Alternative C: Cap on Surface Disturbance, 60 Acres and 30 Acres per Section 

Initial 37,644 5,311 42,955 -4,245 -9.0% 

Long-term 16,455 863 17,318 -1,543 -8.2% 

Alternative D: Directional Drilling 

Initial 31,138 5,311 36,449 -10,751 -22.8% 

Long-term 14,089 863 14,952 -3,908 -20.7% 

Alternative E: No Action 

Initial 0 0 0 -47,200 -100.0% 

Long-term 0 0 0 -18,861 -100.0% 

1 The project area is 1,070,086 acres. 

2-24 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
CHAPTER 2—THE PROPOSED ACTION AND ALTERNATIVES 

Table 2.4-2. Comparison of impacts by alternative 

Feature/Resource Proposed Action 

Alternative A: 

100-Percent 

Vertical Drilling 

Alternative B: 

Enhanced 

Resource 

Protection 

Alternative C: 

Cap (High and 

Low Density 

Areas) 

Alternative 

Directiona

Drilling 

Physical Environment 

Geology The intensity of impacts on geologic resources would vary in relation to the surface disturbance by alte

in all cases providing that best management practices are followed. Impacts would not be significant. 

Paleontology 

Paleontological resources have been identified in over 30 localities within the project area. Implementa

Action or any of the action alternatives may impact paleontological resources—in a negative way by them and making them unavailable for scientific inquiry—to the extent that the ground is disturbed by d(see Table ES-1 above). Disturbance could be beneficial by resulting in the discovery and preservatio

scientific knowledge. Pre-disturbance surveys and disturbance mitigation where appropriate would minThe impact significance criterion would not be exceeded. 

Intermediate 

impact Most impact Intermediate impact Intermediate impact Lowest impa

Soils 

Impacts would be similar for the Proposed Action and all action alternatives but the extent would va

project-related disturbance, from a high of 61,696 acres under Alternative A to a low of 36,449 acres percentage of the CD-C project area soil surface that would be initially disturbed by the Proposed Actalternatives is shown below. These figures should be considered in light of the 5.6 percent of the projhas been disturbed previously. Successful implementation of mitigation measures and BMPs would incriteria were not exceeded. 

4.4 % 5.8 % 4.3 % 4.0 % 3.4 % 

Water Resources:

 Surface Water 

Under the Proposed Action and all action alternatives, surface water impacts could include contam

from the authorized and accidental discharge (spill) of fluids and produced water and the impacts (inclfrom surface disturbance related to the construction of pad sites, roads, and pipelines. The degree of prisk of adverse impacts is related directly to the amount of initial surface disturbance in each alternativ

exceeds at least one of the 8 significance criteria. The number of criteria exceeded for each alternative 

4 criteria 8 criteria 1 criterion 2 criteria 2 criteria 

Water Resources: 

Groundwater 

Significant impacts to groundwater are not expected under the Proposed Action or the action alterna

formations targeted for gas development and produced water disposal are stratigraphically isolated frosprings and flowing wells used for stock and domestic purposes, because of state-of-the-art constructi

because of implementation of BMPs and COAs related to drilling. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
CHAPTER 2—THE PROPOSED ACTION AND ALTERNATIVES 

Table 2.4-2. Comparison of impacts by alternative, continued 

Feature/Resource Proposed Action 

Alternative A: 

100-Percent 

Vertical Drilling 

Alternative B: 

Enhanced 

Resource 

Protection 

Alternative C: 

Cap (High and 

Low Density 

Areas) 

Alternative 

Directiona

Drilling 

Physical Environment, continued 

Air Quality 

Impacts from the Proposed Action and all action alternatives would not cause an exceedance of an

standard and would not exceed the Prevention of Significant Deterioration (PSD) Class II Increments a

from project sources. However, modeled impacts at a100-meter distance from field development projeshort-term concentrations that were predicted to be above the 1-hour NO2 National Ambient Air Qualit

24-hour PM2.5 NAAQS, and the 24-hour PM10 Wyoming Ambient Air Quality Standard (WAAQS). Impa

PSD Class I or Class II increments at any of the Class I and sensitive Class II areas. The visibility anamaximum of 5 days with project emissions resulting in impacts greater than the 0.5 delta deciview (

Δd

Class I and sensitive Class II areas; using the 98th percentile value as a threshold, there are zero days 

threshold. There would be no nitrogen and sulfur deposition impacts that exceed BLM critical load valusensitive Class II area. In addition there would be no impacts to sensitive lakes that exceed threshold energy development projects will comply with applicable air quality regulations and standards, as dete

Biological Environment 

Vegetation 

Vegetation has already been strongly affected; historic disturbance equivalent to 5.6% of the area’s suoccurred. Additional disturbance would produce combined historic and project-related disturbance for 

each action alternative equivalent to the surface area percentages shown below. Even with successf

reclamation practices, about 40 percent of the disturbed area would remain in an unvegetated state du

for the project—45-55 years. The remaining 60 percent of the disturbed area would have reduced prod

is in progress and would have an altered species composition and density for the life of the project and 

term loss of shrubs. Estimated percentage vegetation disturbance by alternative, including the historic

10.0% 11.4% 9.9% 9.6% 9.0% 

Invasive, Non-Native Species 

Initial surface disturbance would create opportunities for invasive species and development activity wo

which such species spread throughout the project area. The principal difference in impacts for the Pro

alternative is related to the amount of surface disturbance that would initially occur for each: 

Intermediate 

impact Most impact Intermediate impact Intermediate impact Lowest impa

Terrestrial Wildlife 

Impacts would include loss of forage, as well as direct and indirect loss of habitat. The percentage of s

crucial winter range that would be disturbed includes historic plus new. Historic disturbance is 7.3% fomule deer. Significant impact can be reached by actions that result in disruption or irreplaceable loss ohabitats such as crucial winter range and migration corridors, resulting in impacts that exceed the High 

definitions. Big game species in the area are expected to be significantly affected by the Proposed Ac

B, and C but not by Alternative D. 

2-26 Continental Divide-Creston Natural Gas Development Project D
CHAPTER 2—THE PROPOSED ACTION AND ALTERNATIVES 

Table 2.4-2. Comparison of impacts by alternative, continued 

Feature/Resource Proposed Action 

Alternative A: 

100-Percent 

Vertical Drilling 

Alternative B: 

Enhanced 

Resource 

Protection 

Alternative C: 

Cap (High and 

Low Density 

Areas) 

Alternative 

Directiona

Drilling 

Biological Environment, continued 

Pronghorn7 High Impact Extreme Impact High Impact High Impact in High Density Area Moderate Imp

Mule Deer7 High Impact Extreme Impact High Impact High Impact in High Density Area Moderate Imp

Aquatic Wildlife 

For the Proposed Action and all action alternatives, impacts to aquatic wildlife are primarily associasediment entering aquatic habitats from ground-disturbing activities and road building adjacent to or cr

significant effects are not expected. Alternative B has additional protections for the Muddy Creek/Bitteother aquatic habitats such as the Chain Lakes wetlands and playas. 

Intermediate 

impact Most impact Intermediate impact Intermediate impact Least impa

Special Status Wildlife 

Those Special Status wildlife species that have potential impacts from the Proposed Action or any of 

approaching or reaching the level of significance are identified below. Sage-grouse within core areas aaffected to a degree that approaches significance because of the SGEO's application on private and sfederal lands. 

Sage-grouse (non-core area only) 

Likely to exceed in 

non-core areas 

Likely to exceed in 

non-core areas 

Not expected to 

exceed 

Less likely to 

exceed than 

Proposed Action 

Not expected 

exceed 

Endangered Fish Impacts to the four Endangered fish found downstream of the project area are not expected to occur u

except for minor water depletion. A determination on potential water depletions is contingent on consu

Sensitive Fish 

Sensitive fish are found primarily in the Muddy Creek drainage; the likelihood of impacts to these specsignificance criteria under the Proposed Action and the action alternatives is: 

Will exceed Will exceed May exceed if actions on 

private lands offset public 

land restrictions 

Likely to 

exceed 

Less likely 

exceed 

7 The impact levels noted for Pronghorn and Mule Deer are based on WGFD (2010) definitions. Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
CHAPTER 2—THE PROPOSED ACTION AND ALTERNATIVES 

Table 2.4-2. Comparison of impacts by alternative, continued 

Feature/Resource Proposed Action 

Alternative A: 

100-Percent 

Vertical Drilling 

Alternative B: 

Enhanced 

Resource 

Protection 

Alternative C: 

Cap (High and 

Low Density 

Areas) 

Alternative 

Directiona

Drilling 

Biological Environment, continued 

Special Status Plants 

Measures aimed at avoiding and protecting special-status plants that would be implemented under the 

action alternatives would insure that special-status plants would be little affected directly. To the exte

disturbance decreases and the number of disturbance sites is reduced, the likelihood of adverse impa

Wild Horses Long-term AUM (animal unit month) loss in Lost Creek and Adobe Town HMAs is estimated at: 

80 AUMs 106 AUMs 77 AUMs 73 AUMs 63 AUMs 

Human Environment 

Visual Resources 

Under the Proposed Action and all action alternatives, adequate visual mitigation in the form of BMapproval would allow oil and gas development to be compatible with the management objectives for V

the project area by partially retaining the existing character of the landscape. Development would be cVRM Class IV objectives because VRM Class IV is meant to allow for major modification of the existinlandscape. There would be no new impacts under Alternative E, No Action. 

Recreation 

The intensity of impacts to recreation would correlate to the variation in long-term surface disturbance 

Intermediate 

impact Most impact Intermediate impact Intermediate impact Least impa

Lands with Wilderness Character (LWC) 

Under the Proposed Action and all alternatives, there would be no impact on LWCs. 

Cultural and Historical Resources 

Pre-disturbance surveys and avoidance would minimize adverse impacts and remove the potential for alternatives; the number of sites that might be identified (and the number potentially eligible for NRHPalternative: 

1,888 (434) 2,467 (568) 1,821 (418) 1,718 (395) 1,455 (362

2-28 Continental Divide-Creston Natural Gas Development Project D
CHAPTER 2—THE PROPOSED ACTION AND ALTERNATIVES 

Table 2.4-2. Comparison of impacts by alternative, continued 

Feature/Resource Proposed Action 

Alternative A: 

100-Percent 

Vertical Drilling 

Alternative B: 

Enhanced 

Resource 

Protection 

Alternative C: 

Cap (High and 

Low Density 

Areas) 

Alternative 

Directiona

Drilling 

Human Environment, continued 

Socioeconomics 

The Proposed Action and the action alternatives would generate similar effects with minor differencproject-related jobs would be created by Year 15 of development. Total project-related employment (d

jobs) would climb to a peak of around 4,000 jobs in Year 14, an addition to existing project employmenwould continue during production after the field is fully developed, but be lower than those during devecompletion of development and production, regional employment would decrease by over 4,300 jobs, existing jobs, a net job loss. Population changes would closely follow employment gains and losses, presidents and almost 1,000 temporary workers during Year 15 of development and falling to about 700 Community facilities should be adequate to accommodate the added population but may require expaof the 15-year development cycle. Demand for community facilities would substantially diminish after dSubstantial government revenues would be generated by the natural-gas production—about $3.8 billioestimated $530 million in state mineral royalties, and $3.1 billion in ad valorem and gross products taxemployment, population, and revenue generation effects would not occur under Alternative E, No Ac

Transportation 

Development-related estimated peak annual average daily traffic (AADT) by alternative is as follows (eproduction-related AADT is the same for all alternatives, 1,360): 

> 3,900 >4,217 Reduced from PA 1-2% Reduced from PA 3-4% Reduced from 

3-11% 

Noise 

The Proposed Action and Alternatives would generate similar types of noise from construction and o

traffic-related noise. The volume of noise would be directly related to the number of well pads for each 

6,126 8,950 5,798 5,299 4,032 

Management Environment 

Range Resources 

Estimated long-term forage loss (AUM equivalent) and number of allotments at risk of exceeding signidecrease in AUMs), by alternative, are as follows: 1,985 AUMs (four allotments at risk) 

2,540 AUMs (more allotments at risk than PA) 

1,921AUMs (fewer allotments at risk than PA) 

1,832 AUMs (fewer allotments at risk than PA) 

1,574 AUMs (fewer allotmeat risk than PA

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
CHAPTER 2—THE PROPOSED ACTION AND ALTERNATIVES 

Table 2.4-2. Comparison of impacts by alternative, continued 

Feature/Resource Proposed Action 

Alternative A: 

100-Percent 

Vertical Drilling 

Alternative B: 

Enhanced 

Resource 

Protection 

Alternative C: 

Cap (High and 

Low Density 

Areas) 

Alternative 

Directiona

Drilling 

Management Environment, continued 

Oil and Gas and Other Minerals 

Under the Proposed Action and all action alternatives, the natural gas resources of the project area Natural gas reserves produced over the life of the project are estimated at 12.02 trillion cubic feet. Und

Operators would still possess lease development rights but it is assumed that fluid mineral resources wunder this proposal. 

Health and Safety The Proposed Action and all action alternatives would result in similar impacts to the public and site 

increased risk of vehicle collisions on interstate highways and local road systems. 

Waste and Hazardous Materials 

Currently authorized and approved actions are already exerting stress on the permitted and authorized proximal to the project area. Authorization of the Proposed Action or Alternatives A through C wouthe capacity of permitted waste management units used by the operating companies, including those u

solid waste, produced water, and drilling mud. Alternative D may serve to extend the life of some exis

2-30 Continental Divide-Creston Natural Gas Development Project D
3. AFFECTED ENVIRONMENT 

 PHYSICAL ENVIRONMENT 

3.1 GEOLOGY 

3.1.1 Physiography 

The project area straddles the Continental Divide and lies within the Great Divide Basin of south-central 

Wyoming, a subsidiary basin of the Greater Green River Basin. Important natural landmarks in the area 

and their corresponding elevations are shown in Table 3.1-1. 

Table 3.1-1. Important natural landmarks in the CD-C project area (north to south) 

Landmark Location Elevation (feet) 

Lost Creek Butte NW 1⁄4 Section 24, T23N:R95W 6,745 

Stratton Knoll N 1/2 Section 28, T23N:R91W 6,879 

Ruby Knolls Sections 26 and 27, T22N:R92W 7,165 

Windy Hill (mesa) Sections 1–5, 7–12, and 18, T21N:R91W 7,125 

Latham Point SW 1⁄4 Section 32, T21N:R92W 7,235 

Tipton Buttes NE 1⁄4 Section 27, T20N:R96W 7,094 

Cow/Horse Butte SE 1⁄4 NE 1⁄4 Section 5, T19N:R91W 7,170 

High Point SW 1⁄4 SW 1⁄4 SE 1⁄4 Section 17, T19N:R92W 7,321 

Sugarloaf SE 1⁄4 SW 1⁄4 Section 5, T18N:R92W 7,088 

Pine Butte Center of NW 1⁄4 Section 10, T17N:R92W 6,808 

Baldy Butte SW 1⁄4 NW 1⁄4 SW 1⁄4 Section 12, T17N:R92W 6,920 

North Flat Top SW 1⁄4 Section 35 T15N:R93W and NW 1⁄4 Section 2, T14N:R93W 7,822 

East Flat Top Center of the E 1/2 Section 18, T14N:R92W 7,560 

The Continental Divide splits the project area into approximately northern and southern halves and, to a 

greater or lesser degree, parallels the I-80 highway and utilities corridor. Along and just north of the I-80 

corridor, Five Mile Ditch, Latham Draw, and Hansen Draw drain the western part of the Great Divide 

Basin, whereas Buck Draw and Creston Draw drain to the northeast, off Latham Mesa. Farther north and 

northwest, the physiography of the project area is dominated by eolian features, and most watercourses 

are short and drain into small to very large interior basins. North of Tipton, the topography of the Red 

Desert Basin, the Lost Creek Basin, Chain Lakes Flat, and Battle Springs Flat is typified by eolian flats 

and dry playas lying in broad topographic depressions surrounded by areas of vegetated sheet or dune 

sand. These larger depressions are developed between elevations of about 6,450 and 6,600 feet. Dozens of 

smaller, internally drained basins occur near and south of the I-80 corridor, most notably including the 

Wamsutter and Frewan Depressions (at about 6,600 to 6,700 feet in elevation), and basins southeast of the 

Creston I-80 exit (S 1⁄2 T20N:R92W and SE 1⁄4 SW 1⁄4 T20N:R91W). Hundreds of smaller, internally 

drained basins occur throughout the project area, especially in places in which the surface rock or soil has 

been covered by dunes or a veneer of windblown sand. 

In the eastern part of the project area, Fillmore Creek is a primary drainage north of the Continental 

Divide. Its principal tributaries include Coal Gulch, Coal Bank Wash, and Badwater Creek. Muddy 

Creek—tributary to the Little Snake River—is the dominant drainage south of the Divide. Its tributaries 

include Holler Draw, Chicken Springs Creek, and Soap Hole Wash that flow south off the Continental 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 3-1 
CHAPTER 3—AFFECTED ENVIRONMENT—GEOLOGY
 

Divide, supplemented by the south-flowing Barrel Springs Draw and Antelope Creek, and the eastflowing Windmill Draw, Red Wash, Blue Gap Draw, Robbers Gulch, Little Robbers Gulch, and the 

North Fork of Cottonwood Creek. Surface elevations within the project area range from a high of 7,822 

feet on North Flat Top in the NW 1⁄4 Section 2, T14N:R93W, to a low of 6,340 feet in the lower drainage 

of Muddy Creek in Section 32, T14N:R91W, making project area relief about 1,482 feet. The slope of the 

land along the floodplain of Muddy Creek within and marginal to the project area is a gentle 400 feet in 

26.2 miles, or about 0.29 percent. Limited areas of exposed rock forming rugged badland hills border the 

Muddy Creek valley to the east and west, and some of these badland hills exhibit slopes of up to 13.7 

percent for short distances. The region of greatest physical relief in the study area—along North Flat Top 

in Section 35, T15N:R93W—has a slope of 18.9 percent, or about a 1,000-foot rise in elevation per mile. 

The majority of the project area, however, shows gentler slopes of 1.7 to 4.2 percent (about 90–220 

feet/mile). 

The project area is dominated by semiarid desert that receives an average of 7.1 inches of annual 

precipitation, ranging from 3.8 inches to 13.6 inches. The annual temperature ranges from -30 oF in winter 

to more than 100 oF in summer. Sagebrush (Artemisia sp.) is the dominant vegetation and grows in 

patches and thickets. Along the larger drainages sagebrush is supplemented by bunch grasses, cheatgrass, 

greasewood, rabbitbrush, lichens, cottonwood, and a variety of other plants (Roehler 1993). Vegetation is 

wholly absent in several areas of badlands, and gullying can be severe in areas of headward erosion 

derived from badland areas, in places where the overlying sediment has been disturbed, or on poorly 

vegetated slopes greater than 2 percent. Much of the lower reach of Muddy Creek is entrenched in a 

floodplain gully system up to 20 feet in depth. 

3.1.2 Regional Geologic Overview 

The project area lies within the southern and eastern parts of the Great Divide and Washakie structural 

basins, sub-basin regions of the Greater Green River Basin of southernmost central Wyoming. 

Structurally, rocks in the area dip in a curving fashion to the west, southwest, and south of the structural 

high of the Sierra Madre Range, and to the south off the Wamsutter Arch, into the Washakie structural 

basin. 

The west flank of the Sierra Madre is bounded by a major eastward-dipping reverse fault system, along 

which it was elevated over the eastern edge of the Greater Green River Basin (including the Washakie 

Basin) during the Laramide Orogeny of the late Cretaceous to early Tertiary period. These reverse faults 

are not exposed at the surface, but rather lie buried beneath early Tertiary sediments that fill the basin. 

The Washakie and Greater Green River basins to the west, into which the surface rocks dip, are bounded 

by east-west oriented structural highs, the Wamsutter Arch to the north and Cherokee Ridge to the south, 

respectively. The structural axis of Cherokee Ridge trends along the Wyoming/Colorado state line and 

separates the extreme southeastern arm of the Greater Green River Basin of Wyoming from the Sand 

Wash Basin of Colorado. Numerous faults occur along Cherokee Ridge, many of which show evidence of 

recurrent motion throughout the last 20 million years. None of these, however, show indication of 

Quaternary movement (Case et al. 1994). 

Geologic mapping by the U.S. Geological Survey (USGS) and Wyoming Geologic Survey (Weitz and 

Love 1952, Love 1970, Love and Christiansen 1985, Love et al. 1993, Roehler 1973, 1977, 1985; Honey 

and Hettinger, 2004; Hettinger and Honey, 2005) documents that the project area has surface sedimentary 

exposures of Quaternary, Tertiary, and Late Cretaceous age. These deposits are in turn underlain in the 

subsurface by Phanerozoic-age sedimentary rocks of Cretaceous to Cambrian age, which are in turn 

underlain by Precambrian metamorphic bedrock that comprises part of the ancient North American craton 

(continental core) and exceeds two billion years in age. 

3-2 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
 

 

 

 

CHAPTER 3—AFFECTED ENVIRONMENT—GEOLOGY 

Information on geologic units preserved at the surface and in the subsurface within the project area is 

provided in Table 3.1-2; a generalized stratigraphic column of these rocks is provided in Figure 3.1-1. A 

diagram showing the complex stratigraphic relations of Eocene deposits is provided in Figure 3.1-2. 

Table 3.1-2. Surface and subsurface geologic deposits in the CD-C project area 

Geologic Deposit Geologic Age Environment/Lithology Resources 

(PFYC=Probable fossil yield class) 

Surface Deposits 

Unnamed Quaternary Holocene­ Eolian/fluvial/colluvial/ None reported within area, economic 

deposits Pleistocene landslide. Sand, gravel, 

clays, weathered-in-place 

residuum from exposed 

outcrops 

deposits of wind-blown sand 

reported 20–30 miles NNE of the 

town of Baggs, Wyoming, just east of 

the project area 

Green River Formation Early – Middle Lacustrine: near shore Vertebrate (including abundant fish 

 Laney Shale Eocene line/saline flats. Oil shale, and flamingo), invertebrate and plant 

 Godiva Rim Member carbonaceous shale, 

calcareous shale sandstone, 

fossils (BLM PFYC 5 for Formation). 

Oil shale, Halite and trona east of  Wilkins Peak Member mudstone, limestone, Rock Springs. 

 Tipton Tongue marlstone, oolitic and 

 Luman Tongue pisolitic limestone, 

stromatolites, trona, halite 

Battle Spring Formation Paleocene to 

early Eocene 

Terrestrial/alluvial fan/fluvial. 

Arkosic (feldspar-rich) 

sandstone 

Possible vertebrate fossils, but 

correlation uncertain (BLM PFYC 2­

3); Gravel and uranium in Great 

Divide Basin 

Wasatch Formation Early Eocene Terrestrial: fluvial/flood Vertebrate, invertebrate, and plant 

 Cathedral Bluffs plain/swamp, drab to fossils (BLM PFYC 5); coal; 

Tongue varicolored mudstone, petroleum in Table Rock fields; 

 Main Body sandstone, carbonaceous 

shale and coal 

uranium reported in adjacent areas 

near Wamsutter, Creston, and  Niland Tongue Latham 

 Ramsey Ranch 

Member 

Fort Union Formation Paleocene Terrestrial: fluvial/flood 

plain/swamp, chiefly 

somber-colored sandstones, 

mudstones, carbonaceous 

shales and coals 

Vertebrate, invertebrate, and plant 

fossils (BLM PFYC 3); petroleum in 

Table Rock and Wild Rose fields; 

coal, coalbed methane 

Lance Formation Late 

Cretaceous 

Terrestrial: fluvial/ 

floodplain/swamp, brown 

and gray sandstone, shale 

and mudstone, coals, and 

carbonaceous shales 

Vertebrate, invertebrate and plant 

fossil (BLM PFYC 5); coal; coalbed 

methane, petroleum in Barrel 

Springs, Blue Gap, Bush Lake, 

Emigrant Trail, Great Divide, Hay 

Reservoir, Robbers Gulch, 

Wamsutter, and Wild Rose fields 

Subsurface Deposits 

Fox Hills Sandstone Late 

Cretaceous 

Near-shore and marginal 

marine gray shale and 

interbedded grayish-orange 

sandstone 

Petroleum in Table Rock Field, other 

production may be included with 

Lance Formation; potential 

petroleum reservoir rock 

Source: Geologic mapping by the U.S. Geological Survey (USGS) and Wyoming Geologic Survey (Weitz and Love 1952, Love 

1970, Love and Christiansen 1985, Love et al 1993, Roehler 1973, 1977, 1985; Honey and Hettinger, 2004; Hettinger and 

Honey, 2005. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 3-3 
CHAPTER 3—AFFECTED ENVIRONMENT—GEOLOGY 

Table 3.1-2. Surface and subsurface geologic deposits in the CD-C project area, continued 

Geologic Deposit Geologic Age Environment/Lithology Resources 

(PFYC=Probable fossil yield class) 

Lewis Shale Late 

Cretaceous 

Marine shale and sandstone Petroleum in Baldy Butte, Barrel 

Springs, Bastard Butte, Battle 

Springs, Blue Gap, Bush Lake, Coal 

Gulch, Continental Divide, Cow 

Creek, Creston, Delaney Rim Unit, 

Echo Springs, Emigrant Trail, 

Fillmore, Frewen, Gale, Great Divide, 

Hay Reservoir, Lost Creek Basin, 

Lost Creek, Nickey, Red Desert, 

Robbers Gulch, Salazar, Sentinel 

Ridge, Siberia Ridge, Standard 

Draw, Stock Pond, Strike, Table 

Rock, Table Rock SW, Tierney, 

Wamsutter, and Wild Rose fields 

Mesaverde 

Group 

Almond 

Formation 

Late 

Cretaceous 

Marine, terrestrial, deltaic: 

white and brown sandstone, 

sandy shale, coal, 

carbonaceous shale 

Petroleum in Baldy Butte, Barrel 

Springs, Battle Springs, Blue Gap, 

Bush Lake, Coal Gulch, Creston, 

Creston Southeast, Delaney Rim 

Unit, Echo Springs, Emigrant Trail, 

Fillmore, Five Mile Gulch, Frewen, 

Hay Reservoir, Monument Lake, 

Nickey, Red Desert, Robbers Gulch, 

Sentinel Ridge, Shell Creek, Siberia 

Ridge, Standard Draw, Stock Pond, 

Strike, Table Rock, Table Rock SW, 

Tierney, Wamsutter, Wells Bluff, and 

Wild Rose, Windmill Draw fields; 

coal; coalbed methane 

Ericson Late Marine: coastal plain, Petroleum in Battle Springs, 

Sandstone Cretaceous estuary/beach, white Continental Divide, Creston, Echo 

(a/k/a Pine sandstone, lenticular Springs, Fillmore, Five Mile Gulch, 

Ridge or conglomerate, coal Gale, Lost Creek Basin, Monument 

Williams Lake, Sentinel Ridge, Siberia Ridge, 

Fork Standard Draw, Stock Pond, Strike, 

Formation) Table Rock, Wamsutter, Wells Bluff, 

Wild Rose, and Windmill Draw Fields 

Rock 

Springs 

(a/k/a Allen 

Ridge or 

Iles) 

Formation 

Late 

Cretaceous 

Terrestrial, coastal plain 

white to brown sandstone, 

shale, mudstone, coal 

Petroleum in Wamsutter Field; other 

production may be included in 

Mesaverde (undivided); potential 

petroleum reservoir rock 

Blair Late Marine Petroleum in Creston and Table 

(=Haystack Cretaceous Rock Field; other production may be 

Mountains) included in Mesaverde (undivided) 

Formation 

Steele Shale (includes 

Shannon, Sussex 

Sandstones) 

Late 

Cretaceous 

Marine: gray shale, with 

numerous bentonites, 

sandstone 

None reported, potential petroleum 

source and reservoir rock 

Niobrara Formation Late 

Cretaceous 

Marine: light-colored 

limestone, gray limey shale 

None reported, potential petroleum 

source and reservoir rock 

Frontier Formation Late 

Cretaceous 

Marine: deltaic, gray 

sandstone and sandy shale 

Petroleum in Cow Creek and Table 

Rock fields; potential petroleum 

source and reservoir rock 

3-4 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
 

CHAPTER 3—AFFECTED ENVIRONMENT—GEOLOGY 

Table 3.1-2. Surface and subsurface geologic deposits in the CD-C project area, continued 

Geologic Deposit Geologic Age Environment/Lithology Resources 

(PFYC=Probable fossil yield class) 

Mowry Shale Late 

Cretaceous 

Marine: silver-gray, hard 

siliceous shale, with 

abundant fish scales and 

bentonites 

None reported, potential petroleum 

source rock 

Muddy Sandstone Early 

Cretaceous 

Marine: deltaic, gray to 

brown sandstone, 

conglomeratic 

Petroleum in Cow Creek Field; 

potential petroleum reservoir rock 

Thermopolis Shale Early 

Cretaceous 

Marine, black, soft, fissile 

shale 

None reported, potential petroleum 

source rock 

Cloverly Formation 

(=Dakota & Lakota 

Sandstones) 

Early 

Cretaceous 

Terrestrial, variegated 

mudstone, bentonitic, 

conglomeratic sandstone 

Petroleum in Cow Creek Field; 

potential petroleum reservoir rock 

Geologic Deposit Geologic Age Environment/Lithology Resources 

(PFYC=Probable fossil yield class) 

Morrison Formation Jurassic Terrestrial, varicolored 

mudstones, white 

sandstone, bentonite 

None reported; potential petroleum 

reservoir rock 

Sundance Formation Jurassic Marine, green-gray 

glauconitic sandstone and 

shale, underlain by red and 

gray non-glauconitic shale 

and sandstone 

None reported; potential petroleum 

reservoir rock 

Nugget Sandstone Triassic to 

Jurassic 

Eolian, gray to red, massive 

to cross-bedded sandstone 

Petroleum in Cow Creek and Table 

Rock fields; potential petroleum 

reservoir rock 

Chugwater Formation Triassic Terrestrial/mud flat, red 

shale and siltstone, 

sandstone 

Potential petroleum reservoir rock 

Goose Egg Formation Permian to 

Triassic 

Marine, gray to olive 

dolomitic siltstone; red 

sandstone and siltstone, 

gypsum, halite, purple to 

white dolomite and 

limestone 

None reported 

Tensleep Sandstone Pennsylvanian Marine, white to gray 

sandstone with limestone 

and dolomite 

Potential reservoir rock. 

Amsden Formation Mississippian 

to 

Pennsylvanian 

Marine, red and green shale 

and dolomite, persistent red 

to brown sandstone at base 

None reported 

Madison Limestone Mississippian Marine, blue-gray massive 

limestone and dolomite 

Petroleum in Table Rock Field 

Flathead Sandstone Cambrian Marine/shoreline, red, 

banded, quartzose 

sandstone 

None reported 

Unnamed metamorphic 

rocks 

Precambrian Igneous/metamorphic, 

granitic and/or intrusive 

None in area but Sierra Madre 

contain ores of uranium, copper, 

silver, lead, zinc, gold, and barium; 

and industrial (building and 

decorative) grades of quartzite, 

marble, and granite 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 3-5 
CHAPTER 3—AFFECTED ENVIRONMENT—GEOLOGY
 

Figure 3.1-1. Generalized stratigraphic column 

The Battle Spring Formation (not shown in this chart) is a coarse-grained deposit that accumulated along the 

southern flank of the Granite Mountains. It is equivalent to the Wasatch and Green River Formations and possibly 

part of the Fort Union Formation. 

3-6 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
CHAPTER 3—AFFECTED ENVIRONMENT—GEOLOGY
 

Figure 3.1-2. Eocene stratigraphic units, Greater Green River Basin 

Source: Modified from Roehler (1989) 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 3-7 
CHAPTER 3—AFFECTED ENVIRONMENT—GEOLOGY
 

Rock terminology for the Cretaceous (Mesaverde Group, a subsurface unit in the project area) is 

complicated in that scientific studies of these rocks reference a number of different formations within the 

project area. Although the Wyoming Chart of Stratigraphic Nomenclature lists the Almond, Ericson, 

Rock Springs, and Blair formations within the Mesaverde Group in the Washakie Basin, alternative 

terminology has been used for these same rocks by authors describing the coals of the Mesaverde. Rock 

equivalent names for the Ericson Sandstone include the Williams Fork Formation or Pine Ridge 

Sandstone; for the Rock Springs Formation, the Allen Ridge Sandstone or Iles Formations; and for the 

Blair Formation, the Haystack Mountain Formation. 

Additional details on surface deposits are provided in Section 3.1.3. Petroleum production targets are 

generally in the Mesaverde Group (undivided) in the following fields: Baldy Butte, Barrel Springs, 

Bastard Butte, Battle Springs, Blue Gap, Coal Gulch, Continental Divide, Cow Creek, Creston, Delaney 

Rim Unit, Echo Springs, Emigrant Trail, Fillmore, Five Mile Gulch, Frewen, Hay Reservoir, Lost Creek 

Basin, Monument Lake, Red, Red Desert, Robbers Gulch, Salazar, Sentinel Ridge, Shell Creek, Siberia 

Ridge, Stock Pond, Strike, Table Rock, Tierney, Wamsutter, Wells Bluff, Wild Rose, and Windmill 

Draw. 

3.1.3 Quaternary Deposits 

Quaternary deposits in the project area include widespread deposits of alluvium, colluvium, and slope 

wash; eolian sand dunes; and residuum developed on formations of Cretaceous (Lance Formation), 

Paleocene (Fort Union Formation), and Eocene (Battle Spring, Green River, and Wasatch Formations) 

ages. 

Extensive deposits of windblown sand blanket bedrock exposures of Tertiary rocks in T15-17N:R93W, 

with more isolated deposits occurring in T15N:R92W (Love and Christiansen 1985). These deposits 

range in thickness up to about 30 feet, and the sediment has been partly stabilized by vegetation, 

dampness, and weak cementation in some areas. Relatively pure, naturally size-sorted eolian sand is an 

economic resource, and sand-quarry pits have been developed in Section 9, T15N:R92W and just to the 

southeast of that area, outside the project boundaries (Harris 1996). The northern part of the project area 

is dominated by eolian deposits and an eolian-created topography. The Red Desert, Lost Lake, and String 

Lake Basins are deflated playas surrounded by loess deposits. 

Deposits of alluvium, at least up to 30 feet thick, are developed in the bed and floodplain of Muddy Creek 

in the central and southeast parts of the project area, and much thinner alluvial accumulations occur in the 

beds of tributary streams near where they join Muddy Creek. The alluvium consists for the most part of 

medium to fine sand, mud, and mudstone rip-up clasts, all derived from the surrounding badland hills. 

Chert pebbles, sandstone clasts, and weathered Eocene soil (paleosol) nodules commonly occur as part of 

streambed loads. Pebble to cobble-sized gravel forms some of the ancient terrace sediment above Muddy 

Creek on its east side, and these deposits are exploited locally as road metal or in making concrete filler 

(for example, in the SW 1⁄4 SE 1⁄4 Section 21, T18N:R91W). The site of the lauded “Rawlins Mammoth,” 

discovered in 1961, is located near Chicken Springs in the NW 1⁄4 SW 1⁄4 SE 1⁄4 Section 1, T18N:R91W. 

Drapes of colluvial sediment, consisting mainly of mud with a lesser amount of fine sand and lag 

accumulations of Eocene soil nodules, border nearly all the badland hills and are derived from them. 

Terrace gravel and gravel deposits of Holocene and perhaps Pleistocene age occur sporadically 

throughout the area along the former course of Muddy Creek and at higher elevations. Older high-level 

terrace gravels suggest that Muddy Creek and its subsidiary tributaries drained northward into the Great 

Divide Basin in the past and that its present southward drainage into the Little Snake River was the result 

of stream piracy. 

3-8 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
CHAPTER 3—AFFECTED ENVIRONMENT—GEOLOGY
 

3.1.4 Tertiary—Battle Spring Formation 

The Battle Spring Formation (Pipiringos 1961) is a fluvial deposit of middle Eocene age that forms a 

foundation for most of the buttes and mesas bordering the playas in the project area north of the 

Continental Divide. The unit consists of gray, orange, and red mudstones, volcanic mudstones, 

carbonaceous mudstones, orange and brown sandstones, and stringers of gravel conglomerate, and it is 

especially well exposed in the area of Ruby Knolls and on the east side of Frewan Mesa. The Battle 

Spring Formation has yielded a small fauna of fossil vertebrates, including the fragmentary bone of a 

crane or a large, flightless bird discovered during reconnaissance fieldwork for this project. 

3.1.5 Tertiary—Green River Formation 

Within the project area, the Eocene Green River Formation (chiefly of middle Eocene age) is restricted to 

the area around the I-80 corridor (between Wamsutter and Tipton Buttes) and to the extreme southwest, 

where it makes up the upper part of the escarpment forming Flat Top Mountain. From oldest to youngest, 

the Green River consists of the Luman Tongue, the Tipton Tongue, Wilkins Peak Member (lower part 

only), Godiva Rim Member, and the Laney Member. Sediments comprising the Green River Formation 

accumulated in environments in and adjacent to Lake Gosiute (and its predecessor Lake Luman) in 

response to the rise and fall in lake level during the Early Eocene. Environments of deposition included 

fluvial, paludal, freshwater lacustrine, saltwater lacustrine, pond and playa lake, evaporate pans, mudflat, 

and volcanic and fluviovolcanic (Roehler 1993). 

The Luman Tongue forms the base of the Green River Formation on the southern edge of the Great 

Divide Basin. The tongue is composed chiefly of organic-rich oil shales, carbonaceous shales, limestones, 

sandstones, and mudstones that accumulated in Lake Luman above deposits of the Ramsey Ranch 

Member of the Wasatch Formation (Section 3.1.6). The Luman deposits interfinger laterally to the north 

and south with varicolored (chiefly red) floodplain deposits of the Wasatch Formation. At its maximum 

extent, Lake Luman occupied an area of about 6,650 square miles. 

The Tipton Tongue (including the Scheggs and Rife beds) of the Green River Formation conformably 

overlies the Niland Tongue of the Wasatch Formation, and is composed chiefly of marlstone, calcareous 

shale, and oil shale. The Scheggs Bed is predominantly oil shale and lesser algal limestones, sands, and 

muds that accumulated in lake and lake-shore environments during the first major expansion of ancient 

Lake Gosiute. Deep-lake oil shale in the Scheggs Bed preserves abundant fossils of ostracods and 

shallow-water lake sediments containing abundant stromatolites, the remains of calcareous algal reefs. 

The stromatolites exhibit a wide variety of bizarre forms that are related to ecological conditions such as 

water depth, temperature, salinity, and sedimentation rate, as well as other factors. The Rife Bed forms 

the top of the Tipton and consists chiefly of organic-rich oil shale, interbedded with a lesser amount of 

algal limestone, dolomite, sandstone, and mudstone. The oil shale of the Rife accumulated in the deepest 

parts of the lake during a 500,000-year period when Lake Gosiute dwindled to about half its former size 

(about 7,500 square miles) during deposition of the Scheggs Bed. The salinity of the lake must have 

increased dramatically as evidenced by thin layers of saline minerals such as nahcolite and disseminated 

crystals of shortite that occur in the upper part of the bed. Algal limestone and sands accumulated in 

shallower and shoreline areas. 

The Wilkins Peak Member consists of many layers of cyclic sediments that include, in ascending order: 

oil shale, trona, halite, and mudstone that accumulated in Lake Gosiute. Only the lower part of the 

member is present in the project area. This part of the member consists chiefly of shales, sandstones, and 

trona and halite that accumulated in brackish Lake Gosiute as the lake shrank in size. The Godiva Rim 

Member consists chiefly of gray-brown kerogenous shale, ostracode-bearing sandstone, siltstone, and 

limestone that overlie and interfinger with the Cathedral Bluffs Member of the Wasatch Formation and is 

overlain and interfingers with the LaClede Bed of the Laney Shale. 

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The Laney Shale (including the LaClede and Hartt Cabin beds) forms the top of the Green River 

Formation and records in its sediments the greatest expansion of ancient Lake Gosiute followed by its 

final contraction and desiccation. At its peak the lake in which the Laney accumulated occupied more 

than 75 percent of the Greater Green River Basin, or about 15,000 square miles (Bucheim 1981,1986, 

Bucheim et al. 1977).The Laney Shale (including the LaClede and Hartt Cabin Beds) conformably 

overlies and interfingers with the Cathedral Bluffs Tongue of the Wasatch Formation, and is dominated 

by calcareous shale, oil shale, and shaley marlstone. 

In the Piceance Basin of Colorado, the Green River Formation contains massive amounts of economically 

important oil shale, and elsewhere the formation is also known to yield economically important deposits 

of trona and gilsonite. The Green River is well known for its locally abundant remains of well-preserved 

fossil fish and much rarer specimens of other fossil vertebrates. 

3.1.6 Tertiary—Wasatch Formation 

The lower Eocene Wasatch Formation is the most extensively exposed geologic unit in the project area, 

with a distribution exceeding that of any other rock unit. Bedrock exposures of the Wasatch Formation, 

however, are generally limited to the steep, east-facing escarpments bordering much of the west side of 

Muddy Creek, especially beneath Flat Top Mountain, along “The Bluffs” north of Baggs, and in westdipping cuestas north and south of the townsite of Dad. Other exposures are locally developed along and 

marginal to deeply incised streams on south Mexican Flats. 

Within the project area, the Wasatch Formation is divided into the Main Body, Ramsey Ranch Member, 

Niland Tongue, and the Cathedral Bluffs Tongue. Regionally, the Main Body of the Wasatch Formation 

consists of up to 2,130 feet of variegated mudstone and sandy mudstone, gray sandstone, carbonaceous 

shale, and coal (Bradley 1964; Sullivan 1980; Roehler 1985) that were deposited in alluvial channels and 

back swamps, and on floodplains. Toward the basin center, the Main Body of the Wasatch conformably 

overlies the Paleocene Fort Union Formation, but farther east it overlaps the Fort Union and lies with 

angular unconformity on both the Fort Union Formation and the Upper Cretaceous Lance Formation. The 

floodplain deposits of the Main Body have two distinct color patterns. Around the basin edges the 

floodplain deposits range from red to varicolored, with some shade of red dominating. In the central parts 

of basin these red floodplain deposits are replaced laterally by green to gray floodplain deposits. Green to 

gray coloration appears to have been the result of accumulation of sediments in areas that were 

permanently water saturated, where iron compounds were reduced. In addition to floodplain deposits the 

main body of the Wasatch Formation includes some freshwater limestones that accumulated in ponds and 

marshes in low-lying areas and some coarse-grained sands and conglomerates that accumulated along the 

basin margin in alluvial fan environments. Deposits of the Main Body accumulated contemporaneously 

with deposits of the Ramsey Ranch Member of the Wasatch Formation and Luman and Tipton tongues of 

the Green River Formation. 

The Ramsey Ranch Member consists of carbonaceous shale, coal, limestone, gray and green or red 

variegated sandstone and mudstones that accumulated in swamps, shallow lakes and ponds, and 

floodplains and rivers during the early stages of the development of Lake Gosiute. The member contains 

important deposits of oil shale, uranium, and coal. 

The Niland Tongue of the Wasatch Formation consists of brown sandstone, drab mudstone, and 

carbonaceous shale that conformably overlie the Luman Tongue of the Green River Formation. The 

Niland Tongue has the same aerial distribution as the Luman Tongue of the Green River Formation. 

Where the Luman Tongue is absent the name Niland Tongue is discarded and those rocks are not 

separated from the underlying main body of the Wasatch. 

The Cathedral Bluffs Tongue forms the uppermost rocks of the Wasatch Formation, overlying the Tipton 

Shale of the Green River Formation, and closely resembles those of the Main Body in the dominance of 

variegated mudstone and gray sandstone. 

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Economically important uranium deposits occur in coals of the Main Body and Ramsey Ranch Member 

of the Wasatch Formation north of Wamsutter, just west of the project area (Masursky 1962), and in the 

region around Creston and Latham (Harris et al. 1985; Harris and King 1993). Uranium is also known in 

arkoses of the Battle Springs Formation of the central Great Divide Basin (Pipiringos 1961), a unit 

approximately equivalent to the Cathedral Bluffs Tongue of the Wasatch within the report area. 

Fossil vertebrates are locally abundant in the Wasatch Formation, including all the subunits that comprise 

the formation in the CD-C project area. Fossils are most abundant where they have weathered from 

immature through mature paleosols. However, about 10 miles north of Baggs, Wyoming, sandstones of 

the Cathedral Bluff Member that interfingers with the Tipton Shale have produced fossils of 11 

mammalian species including primates, condylarths, tillodonts, dinocerates, and perissodactyls (Roehler 

1988) as well as the fossils of mollusks, ostracodes, burrows, worm trails, and an unidentified tubular 

impression. The mollusks include very abundant shells of the gastropods Goniabasis and Viviparus as 

well as freshwater unionid bivalves. 

The most important Wasatch Formation fossil vertebrate locality within the study area is the so-called 

“Dad Local Fauna” (Gazin 1962), which was collected from the east-facing exposures of the Main Body 

of the formation developed on bluffs north and south of the townsite of Dad. The University of Wyoming 

Geological Museum has 11 fossil vertebrate sites in the Wasatch Formation within the project area. 

3.1.7 Tertiary—Fort Union Formation 

Within the project area, the Paleocene Fort Union Formation is developed in a curved, westerly dipping 

outcrop. Regionally, the unit lies with erosional or angular unconformity atop the Upper Cretaceous 

Lance Formation (Roehler 1993). The best Fort Union exposures occur in the northeast part of the area, in 

Section 23, T18N:R92W; however, good but smaller and less-continuous Fort Union exposures occur 

beneath Wasatch-capped buttes developed just east of Muddy Creek, between the townsites of Dad and 

Baggs, Wyoming. 

Regionally, the Fort Union Formation consists of up to 3,400 feet of drab mudstone, sandy mudstone, 

sandstone, carbonaceous shales, and coal. These rocks were deposited in alluvial channels and flood-basin 

backswamps (Sanders 1975), and up to 1,500 feet of Fort Union rocks are exposed in the Riner area, 

between Red Rim and Creston Junction (Sanders 1974). 

Honey and Hettinger (2004) and Hettinger and Honey (2005) have mapped three members of the Fort 

Union Formation in the Blue Gap and Peach Orchard 7.5-minute quadrangles. These include, from 

youngest to oldest, the Overland, Blue Gap, and China Butte Members. The China Butte Member 

includes many mapped coalbeds included in five coal-bearing zones. These include the Fillmore Ranch, 

upper and lower Muddy Creek, Olsen Draw, and Red Rim coal zones. 

The Fort Union Formation in the project area, as well as in all of south-central Wyoming, constitutes an 

enormous, largely untapped reserve of coal. Unfortunately, most of this resource occurs in thin and/or 

discontinuous beds (Smith et al. 1972; Sanders 1974, 1975; Beaumont 1979; Edson 1979; Hettinger and 

Brown 1979; Honey and Roberts 1989; Honey and Hettinger 1989a; Honey 1990; Jones 1991; Hettinger 

et al. 1991; Hettinger and Kirchbaum 1991) that are exceedingly difficult to mine economically. Sanders 

(1974, 1975) reports thin and discontinuous Fort Union coalbeds that thicken up to 9.8 feet in places, and 

units 5–25 feet thick are developed in the upper 600–700 feet of the formation just northeast of the project 

area. Edson (1979), Honey and Hettinger (1989a), Honey and Roberts (1989), and Honey (1990) named 

and/or numbered Fort Union coalbeds within and north and west of the project area, and provided 

subsurface correlations of coal-bearing units. Honey and Roberts (1989) recorded up to 75 feet of total 

coal thickness in the lower part of the Fort Union Formation in the Baggs area, and Honey and Hettinger 

(1989b) documented individual coalbeds up to 27.7 feet thick in the Fillmore Ranch Coal Zone (Edson 

1979), within the project area. 

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The most recent coal-mining activity within the project area is in the Fort Union Formation at Cherokee 

Mine Number 1, in the SW 1⁄4 SW 1⁄4 NE 1⁄4 Section 2, T19N:R92W, about 6 miles south of Creston 

Junction. Coal mining is also planned for the Creston Area (in T19N:R92W), and at the Chris Butte Mine 

Project area along the Continental Divide in Section 15, T18N:R91W. 

Fossil vertebrates are well known from the China Butte Member of the Fort Union Formation within the 

study area, the most noteworthy locality being Swain Quarry, in the NE 1⁄4 Section 3, T15N:R92W (Rigby 

1980). Apart from Swain Quarry, the UW Geological Museum has one locality in the project area—Fort 

Union rocks—and an additional 13 Fort Union sites have been developed in recent years by M.C. 

McKenna and J.G. Honey. 

The contact of the Fort Union Formation with the underlying Upper Cretaceous Lance Formation is 

everywhere marked by a pronounced angular unconformity and generally a thick-channel sandstone 

(Roehler 1993). It is unknown if the Tertiary-Cretaceous boundary is preserved in the area, but earliest 

Paleocene (Puercan age) rocks certainly are (see Section 3.3 Soils). 

3.1.8 Upper Cretaceous—Lance Formation 

Few exposures of Lance rocks extend into the project area, and the Lance Formation/Fort Union 

Formation contact in part forms the project area’s eastern boundary over a short distance. However, 

patches of Lance are exposed in a few areas, notably in the SE 1⁄4 Sections 13, 23, and 34, T17N:R92W, 

and in the E 1⁄2 Section 4, T16N:R92W. 

The Lance Formation is a largely alluvial deposit made up of about 2,890 feet of interbedded gray 

sandstone and sandy mudstone, carbonaceous shale, and coal (Hettinger et al. 1991; Hettinger and 

Kirschbaum 1991). Honey and Hettinger (2004) and Hettinger and Honey (2005) recognize two subunits 

of the Lance Formation in the Blue Gap and Peach Orchard 7.5-minute Quadrangles. These include an 

upper Red Rim Member and an underlying unnamed member. The Red Rim Member is chiefly 

conglomeratic sandstone. The underlying unnamed member contains several coal units. The thickest of 

these, which is about six feet thick, occurs about 25 to 45 feet above the base of the formation. 

Regionally, the Lance overlies the Fox Hills Sandstone (Smith 1961, Gill et al. 1970, Hettinger et al. 

1991, Roehler 1993), which is included in the Lewis Shale on many maps. To the east the Fox Hills may 

be absent, and the Lance directly overlies the Lewis Shale (Weitz and Love 1952, Love and Christiansen 

1985). Further eastward, Lance rocks correlate with the Medicine Bow Formation (Merewether 1971) and 

farther west, the Lance thins to less than 197 feet on the west side of the Washakie Basin (Roehler 1985). 

The Lance Formation is well-known for its dinosaur remains and, within the project area, Lance rocks 

have yielded sparse remains of fish, crocodilians, and mammals (J.G. Honey, personal communication). 

3.1.9 Geologic Hazards 

Of known naturally occurring geologic hazards, fault-generated earthquakes, floods, landslides, or other 

mass movement, the most likely to affect the project area are mass movements that could be initiated on 

steep slopes. Flooding may be a hazard adjacent to steeply dipping rock outcroppings where high runoff 

may be expected; however, there are few such areas within the project boundaries. 

There are no known faults with evidence of Quaternary movement mapped within the project area (NEIC 

2003, WGS 2003); however, a number of unmapped faults are known to exist in the Washakie Basin area 

in southern Sweetwater and Carbon Counties. Further field investigation is necessary to determine if any 

of these faults should be deemed active (USGS 2012a). 

Only one earthquake has been recorded within the project area. The earthquake, with a 4.3 Richter 

magnitude occurred April 4, 1999 and its epicenter was located near Baldy Butte in T17N:R92W 

(41.45 ̊N:107.74 ̊W). It was felt in Rawlins, Sinclair, Baggs, Wamsutter, and Rock Springs. Residents of 

Rawlins reported that pictures fell off walls. The most noteworthy damage occurred between Baggs and 

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Creston Junction, and at Wamsutter (USGS 2012a). The owner of a ranch house located approximately 30 

miles north of Baggs reported that cinder-block walls in the basement of the home cracked, separated, and 

may have required replacement. A motel and associated residence in Wamsutter also suffered cracks in 

the cinder-block walls of the basement. No other earthquake epicenters have been recorded in or 

immediately adjacent to the area in the past 100 years, indicating that earthquakes are probably an 

unusual event and that the area may not be very seismically active (USGS 2012a). 

Carbon County is primarily in Seismic Zone 1 of the Uniform Building Code. Effective peak 

accelerations (90 percent chance of non-exceedance in 50 years) in this zone can range from 5%g–10%g, 

where g = the gravitational acceleration constant (see Glossary). New probabilistic acceleration maps for 

Wyoming are available from the USGS (USGS 2012a). These maps assume accelerations based on what 

would be expected if firm soil or rock were present at the surface. 

Ground accelerations shown on the USGS maps in Wyoming may be affected by local soil conditions. If 

fairly soft, saturated sediments are present at the surface, and seismic waves pass through them, surfaceground accelerations will usually be greater than would be experienced if only bedrock were present. 

Thus, ground accelerations shown by the USGS maps may underestimate the local hazard. 

The USGS maps indicate that in the southern part of Carbon County: (1) for the 500-year map (10 percent 

probability of exceedance in 50 years), the estimated peak horizontal acceleration in Carbon County is 

about 4%g; (2) for the 1,000-year map (5 percent probability of exceedance in 50 years) is about 3.9%g; 

and (3) for the 2,500-year map (2 percent probability of exceedance in 50 years) is about 11%g. These 

accelerations are roughly comparable to intensity V and VI earthquakes. An intensity VI earthquake can 

result in fallen plaster and damaged chimneys. 

The historic record of earthquakes is limited and it is nearly impossible to determine when a 2,500-year 

event last occurred in the county. This uncertainty, coupled with use by the International Building Code 

of the record of 2,500-year events for building design, suggests that it is appropriate to use the 2,500-year 

probabilistic maps for Carbon County analyses. 

Honey and Hettinger (2004) have mapped landslide deposits covering about a quarter-section along the 

north side of Cottonwood Creek in Section 31, T14N:R92W and Section 6, T13N:R92W of the Peach 

Orchard 7.5-minute topographic quadrangle. These deposits are of limited extent and occur along the 

contact between the Main Body of the Wasatch Formation and overlying Tipton Tongue of the Green 

River Formation. 

3.2 PALEONTOLOGIC RESOURCES 

3.2.1 Paleontological Resource Preservation Act 

The Paleontological Resources Preservation Act (PRPA 2009) was signed into law as part of the Omnibus 

Public Lands Management Act of 2009, Public Law 111-011 (123 Stat. 1173; 16 USC 470aaa) (OPLMA 

2009). It states that these resources on federal land (except Indian land) shall be managed and protected 

“using scientific principles and expertise” and also requires the development of “appropriate plans for the 

inventory, monitoring, and scientific and educational use of these resources” in accordance with 

applicable agency laws, regulations, and policies. These plans emphasize interagency coordination and 

collaborative efforts where possible with non-federal partners, the scientific community, and the general 

public. In addition, programs to increase the public's awareness about the significance of paleontological 

resources are to be established. 

The PRPA formally defines paleontological resources as “any fossilized remains, traces, or imprints of 

organisms, preserved in or on the earth’s crust, that are of paleontological interest and that provide 

information about the history of life on earth,” and as such include the fossilized remains of plants and 

animals as well as their traces. 

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CHAPTER 3—AFFECTED ENVIRONMENT— PALEONTOLOGIC RESOURCES 

3.2.2 Potential Fossil Yield Classification (PFYC) System 

The PFYC system is described in BLM Instruction Memorandum [IM] No. 2008-009, Potential Fossil 

Yield Classification (PFYC) System for Paleontological Resources on Public Lands (BLM 2007d). The 

IM is summarized here and is included in its entirety in Appendix D, Paleontological Resources 

Program Guidance. The system is based on the premise that the probability of finding paleontological 

resources can be broadly predicted from the geologic units present at or near the surface. Under the 

system, geologic units are classified according to the relative abundance of fossils and their sensitivity 

to adverse impacts, with a higher class number indicating a higher potential. 

The PFYC system provides baseline guidance for predicting, assessing, and mitigating paleontological 

resources. The classification is an intermediate point in the analysis, used to assist in determining the need 

for further mitigation assessment or actions. 

The descriptions for each class (provided below) serve as guidelines rather than as strict definitions. Note 

that the definition of fossil may be redefined in the Rules and Regulations Section of the PRPA, which is 

still in draft. 

Class 1 – Very Low. Geologic units that are not likely to contain recognizable fossil remains. 

 Units that are igneous or metamorphic, excluding reworked volcanic ash units. 

 Units that are Precambrian in age or older. 

The probability for impacting any fossils is negligible. 

Class 2 – Low. Sedimentary geologic units that are not likely to contain vertebrate fossils or 

scientifically significant nonvertebrate fossils.
 

 Vertebrate or significant invertebrate or plant fossils not present or very rare. 

 Units that are generally younger than 10,000 years before present. 

 Recent eolian deposits. 

 Sediments that exhibit significant physical and chemical changes (i.e., diagenetic alteration). 

The probability for impacting fossils is low. 

Class 3 – Moderate or Unknown. Fossiliferous sedimentary geologic units where fossil content varies 

in significance, abundance, and predictable occurrence; or sedimentary units of unknown fossil potential. 

 Often marine in origin with sporadic known occurrences of vertebrate fossils.
 

 Vertebrate fossils and scientifically significant invertebrate or plant fossils known to occur 

intermittently; predictability known to be low. 

 (or)
 

 Poorly studied and/or poorly documented. Potential yield cannot be assigned without ground 

reconnaissance. 

Class 3a – Moderate Potential. Units are known to contain vertebrate fossils or scientifically significant 

nonvertebrate fossils, but these occurrences are widely scattered. 

Class 3b – Unknown Potential. Units exhibit geologic features and preservational conditions that 

suggest significant fossils could be present, but little information about the paleontological resources of 

the unit or the area is known. 

Class 4 – High. Geologic units containing a high occurrence of significant fossils. 

Class 4a – Unit is exposed with little or no soil or vegetative cover. Outcrop areas are extensive 

with exposed bedrock areas often larger than two acres. 

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Class 4b – These are areas underlain by geologic units with high potential but have lowered risks of 

human-caused adverse impacts and/or lowered risk of natural degradation due to moderating 

circumstances. Extensive soil or vegetative cover; bedrock exposures are limited or not expected to 

be impacted. Areas of exposed outcrop are smaller than two contiguous acres; outcrops form cliffs 

of sufficient height and slope so that impacts are minimized by topographic conditions; other 

characteristics are present that lower the vulnerability of both known and unidentified 

paleontological resources. 

The probability for impacting significant paleontological resources is moderate to high, and is
 

dependent on the proposed action. 

Class 5 – Very High. Highly fossiliferous geologic units that consistently and predictably produce 

vertebrate fossils or scientifically significant invertebrate or plant fossils, and that are at risk of humancaused adverse impacts or natural degradation. 

Class 5a – Unit is exposed with little or no soil or vegetative cover. Outcrop areas are extensive 

with exposed bedrock areas often larger than two contiguous acres. 

Class 5b – These are areas underlain by geologic units with very high potential but have lowered 

risks of human-caused adverse impacts and/or lowered risk of natural degradation due to 

moderating circumstances. 

The probability for impacting significant fossils is high. 

3.2.3 Known Paleontological Resources in the CD-C Project Area 

Known paleontological resources (frequently referred to here as fossils or fossil resources) within 

sedimentary deposits in the project area record the history of animal and plant life in Wyoming during the 

early part of the Cenozoic Era (Paleocene and Eocene Epochs) and the latest part of the Mesozoic 

(Cretaceous Period) Era. As described above, current mapping documents six geologic deposits exposed 

at the surface in the project area. These include, from youngest to oldest: (1) unnamed deposits of 

Quaternary (Holocene to Pleistocene) age, (2) the middle Eocene Battle Spring Formation, (3) the middle 

and early Eocene Green River Formation, (4) the Wasatch Formation of early Eocene age, (5) the Fort 

Union Formation of Paleocene age, and (6) the Lance Formation of Latest Cretaceous age. 

With the exception of the Holocene deposits that are probably too young to contain fossils, all 

sedimentary rock units exposed in the project area are known to produce or have the potential to produce 

scientifically significant fossil resources. Scientifically significant fossils have been recovered from the 

Wasatch (Morris 1954; Honey 1988; Roehler 1972, 1991a–b, 1992a–c, 1993; Roehler et al. 1988), Fort 

Union (Rigby 1980, Winterfeld 1982), and Lance Formations (Dorf 1942, Estes 1964, Clemens 1986, 

Clemens et al. 1979, Breithaupt 1982 and 1985, Weishample 1992, Archibald 1993, Lillegraven 2002, 

Honey 2003) within the project area or immediately adjacent areas. 

Specifically, 15 fossil localities are known to occur within the project area in the Lance Formation and 17 

fossil localities are known to occur within the Fort Union Formation. The Lance Formation localities 

occur in the Separation Peak (T20N:R90W), Fillmore Ranch (T18N:R20W), Doty Mountain (T17N:R91– 

92W), Peach Orchard Flat (T15N:R91W) and Blue Gap (T15N:R91W) 7.5-minute Quadrangles. The Fort 

Union Formation localities occur in the Separation Peak (T20N:R90W), Fillmore Ranch (T19N:R91W), 

Duck Lake (T16–17N:R91-91W), Mexican Flats (T16N:R92W) and Blue Gap (T15–16N:R91–92W) 7.5­

minute Quadrangles. Localities from both the Lance and Fort Union Formations produce a wide variety of 

fossil remains, including those of mammals, reptiles, amphibians, and fish. Of great importance is the 

occurrence within the Fort Union Formation of some of the oldest known Paleocene-age fossil vertebrates 

in the world, which are considered to be of Puercan age (earlier Paleocene) and are very rare (Honey 

2003). 

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Literature review and the field survey documented the occurrence of known scientifically significant 

fossils within the CD-C area in the following formations: (1) the middle Eocene Battle Spring Formation 

(PFYC 3b [unknown]), (2) the middle and early Eocene Green River Formation (PFYC 5, very high), (3) 

the Wasatch Formation of early Eocene age (PFYC 5, very high), (4) the Fort Union Formation of 

Paleocene age (PFYC 3a, moderate), and (5) the Lance Formation of Latest Cretaceous age (PFYC 5, 

very high). 

3.2.4 Taphonomy and the Occurrence of Fossils 

Taphonomy is the study of the origin and nature of accumulations of fossil materials or their traces. In 

general, vertebrate fossils are much rarer than invertebrate fossils, but there are sites where extraordinary 

accumulations of fossil vertebrates are found. 

Knowledge of the geologic context of vertebrate fossils collected at a site is critically important in 

evaluating the reason fossils occur where they do. The geological context of a deposit contains 

information about whether the deposit formed under marine (ocean), lacustrine (lake), or fluvial (riverine) 

conditions. In the project area, five geological formations have high potential for yielding fossil 

vertebrates. From oldest to youngest, these are: (1) the Lance Formation (Upper Cretaceous), (2) the Fort 

Union Formation (Paleocene), (3) the Wasatch Formation (lower Eocene), (4) the Green River Formation 

(middle Eocene), and (5) the Battle Spring Formation (middle Eocene). None of these formations is of 

marine origin, and only the Green River Formation was deposited under largely lacustrine conditions. The 

Lance, Fort Union, Wasatch, and Battle Spring formations are dominantly of fluvial (river, stream, and 

associated floodplain) origin. 

In lacustrine environments, fossil vertebrate remains might accumulate in shales deposited under openwater conditions or, closer to shore, in units containing coarser clastic material. Fluvial sediments (those 

deposited by streams) represent two basic environments: the channel and the floodplain. Channel deposits 

are generally dominated by sandstone and/or gravel conglomerate, whereas floodplain sediments consist 

chiefly of mudstones. Because they were subjected to periodic drying during intermittent deposition, 

rocks comprising floodplain deposits are commonly color-variegated. The thicknesses of the colored 

horizons reflect the relative maturity (relative time to form) of the ancient soils (Bown and Kraus 1980a 

and 1980b). 

In fluvial rocks, the accumulation of vertebrate material may be either active or passive. Active 

accumulation involves the concentration of bones by running water. All fossil vertebrate concentrations 

formed by active accumulation are made up of remains that have been transported after death, although 

they need not have been transported very far. 

Passive accumulation includes all mechanisms of concentrating fossil material in fluvial environments in 

which the remains of the organism are not transported to a large extent after death. Examples of passive 

accumulation include: (1) the slow buildup of bones in quicksand deposits, (2) the preservation of remains 

as a result of ash-falls, and (3) the gradual accumulation of the remains of dead animals in the upper (A) 

horizons of soils (paleosol accumulations). Because paleosols are ubiquitous in ancient fluvial sequences, 

and because floodplains with forming soils occupy more than 98 percent of the area of any basinal area of 

fluvial accumulation, the vast majority of vertebrate fossils accumulate as part of passive paleosol 

accumulations (Bown and Kraus, 1981b). Paleosols, like modern soils, form between times of major 

(depositional) events. The amount of vertebrate remains that accumulates during these events can be 

staggering. If only three bones/year accumulated on a soil surface 247 acres in area, as a paleosol that 

formed for 50,000 years, that soil might be expected to yield 150,000 individual bones. 

Lance Formation 

The presence of fossil localities of scientific significance in the Lance Formation is well established and 

has a long history (Breithaupt 1982). One of the earliest discoveries was the remains of a horned dinosaur 

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CHAPTER 3—AFFECTED ENVIRONMENT—PALEONTOLOGIC RESOURCES 

(ceratopsian) discovered about 15 miles southeast of Point of Rocks near the old Black Butte Stage 

Station in 1872. These remains were identified as the new species Agathaumus sylvestris by Cope in 1872 

and represent the first dinosaur remains found in strata now referred to as the Lance Formation. 

Within the project area, the Upper Cretaceous Lance Formation consists of up to 2,900 feet of interbedded 

gray sandstone and sandy mudstone, carbonaceous shale, and coal. The Lance Formation is well-known 

for its dinosaurian remains (Breithaupt 1982); however, the only Lance fossil vertebrates found within the 

project area are some rare fish and crocodilian remains, as well as a few mammal teeth collected from 

anthills (J.G. Honey 2003). The provenance of these remains is uncertain, but they probably came from 

poorly developed paleosols. 

Fort Union Formation 

The Fort Union Formation is exposed within the project area as up to 3,400 feet of drab mudstone, sandy 

mudstone, sandstone, carbonaceous shales, and coal. Fossil vertebrates—especially mammals—are wellknown from Fort Union rocks in and adjoining the study area (Rigby 1980; J.G. Honey 2003), the most 

noteworthy localities being Swain Quarry, in Section 3, T15 N:R 92 W, and another site in the basal part 

of the formation discovered by J.G. Honey, the paleontologist cited in the reference above. Swain Quarry 

yields principally mammal teeth from a sandstone, and both that site and the new site discovered by 

Honey are almost certainly gradual active accumulations of bones on point bars of meandering streams. 

Winterfeld (1982) has recorded the occurrences of fossil vertebrates in greenish to greenish-gray Fort 

Union mudstones. As these deposits are relatively thin and tabular in nature, it is quite likely that they 

represent the “A” horizons of relatively mature damp paleosols, and are therefore passive accumulations. 

Wasatch Formation 

The Ramsey Ranch Member, Main Body of the Wasatch Formation and the Niland and Cathedral Bluffs 

Tongues of the Wasatch comprise bedrock exposures of the Wasatch Formation within the project area. 

Numerous fossil vertebrates, invertebrates, and trace fossils are known from the Main Body throughout 

southern Wyoming (Granger 1916; Gazin 1952, 1956, 1962; 1965; McGrew and Roehler 1960; West 

1973), including deposits previously referred to as the Knight and Almy “formations” by Veatch (1907). 

These fossils include somewhat more primitive forms of rodents, carnivores, early horses, artiodactyls, 

and condylarths than those in the stratigraphically younger Cathedral Bluffs Member and range between 

early to middle early Eocene (early to late Wasatchian) in age. 

Fossil vertebrates are locally abundant in the Wasatch Formation, including all the subunits that comprise 

the formation in the project area. Fossils are most abundant where they have weathered from immature 

through mature paleosols. However, about 10 miles north of Baggs, Wyoming, sandstones of the 

Cathedral Bluff Member that interfingers with the Tipton Shale have produced fossils of 11 mammalian 

species including primates, condylarths, tillodonts, dinocerates, and perissodactyls (Roehler 1988) as well 

as the fossils of mollusks, ostracodes, and burrows, worm trails, and an unidentified tubular impression. 

The mollusks include very abundant shells of the gastropods Goniabasis and Viviparu,s as well as 

freshwater unionid bivalves. These fossil-bearing sandstones represent deposition in a delta system 

prograding into Lake Gosuite. West of the project area, Wasatch vertebrates are described as coming from 

drab, carbonaceous mudstones containing the remains of terrestrial mollusks (Savage et al. 1972; Gazin, 

1962; Savage and Waters, 1978; Williams and Covert, 1994). These deposits appear to be damp 

paleosols. 

Green River Formation 

The Laney Shale (including LaClede and Hartt Cabin beds), Godiva Rim, Wilkins Peak (lower part only) 

members and Tipton (including the Scheggs and Rife beds) and Luman tongues comprise bedrock 

exposures of the Green River Formation within the project area (Roehler 1991a, 1991b, 1992a, 1992b, 

1992c, 1993). 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 3-17 
CHAPTER 3—AFFECTED ENVIRONMENT— PALEONTOLOGIC RESOURCES 

Apparently, the only fossils known from the Godiva Rim Member are ostracodes. The Laney Shale is 

quite fossil-rich in places and is well-known for its fossil fish. Fossil gastropods, bivalves, and fish are 

common in the LaClede Bed. Small planorbid gastropod fossils of Gyralus militaris are extremely 

abundant and widespread in one particular layer (about a foot thick) that is recognized as a stratigraphic 

marker bed, the Gyralus Marker Bed. Impressions of plants and insects also occur in some shales of the 

LaClede Bed. Stromatolites—the remains of ancient reefs—also characterize the unit. Some of the 

stromatolies may be as much as 25 feet high and 10 feet wide. The Hartt Cabin Bed produces abundant 

fossil vertebrates, mostly fish, but also reptiles and mammals, along the eastern edge of the Washakie 

Basin at Willow Creek. 

Plant, invertebrate, and vertebrate fossils have been reported from the Wilkins Peak Member 

elsewhere in Wyoming (Grande 1984, 1989; Olsen 1987, 1992). Roehler (1974) noted a fossil bird 

locality in the member south of Rock Springs at Scrivner Butte. Another fossil bird locality occurs a few 

miles away in the Four J Rim Quadrangle. This locality has yielded the dissociated skeletons, including 

skulls, of the wading bird Presbyornis. The number of individual birds preserved in the layer may number 

into the many thousands. Hundreds of fossil flamingo bones, apparently the remains of a large nesting 

colony, have been collected from a locality developed in rocks of the lower part of the member at a 

locality discovered near Oregon Buttes in gray-green lake claystone (McGrew and Feduccia 1973). The 

locality was originally described as occurring in the Cathedral Bluffs Member of the Wasatch Formation, 

but its location in lake sediments means that the locality actually occurs in the Wilkins Peak Member. 

The Scheggs Bed preserves the fossil remains of ostracodes, gastropods, such as Goniabasis tenera and 

Viviparus sp., and the large unionid bivalve Lampsilis. Fish fossils also occur abundantly along outcrops 

of the Scheggs Bed (Roehler 1991a, 1991b, 1992a, 1992b, 1992c, 1993). One fossil mammal locality 

occurs in the Scheggs Bed and this locality, discovered in an ostracodal limestone along Parnel Creek a 

few miles north of Rock Springs, (T24N:R102W) produced the mold of a jaw of the early horse 

Hyracotherium, with incisors and molar impressions. Roehler (1992c) noted that fossil fish are locally 

abundant in the Rife Bed in the Sand Wash and Washakie basins. 

Fossils of freshwater molluscs are abundant throughout the Luman Tongue and the assemblages of fossils 

are commonly characterized by the large prosobranch gastropods Goniabasis tenera and Viviparus sp. 

and by the large unionid bivalve, Lampsilis sp. Fish, ostracod, and trace fossils are also common in the 

unit. 

Battle Spring Formation 

The Battle Spring Formation was named by Pipiringos (1955) for up to 3,300 feet of arkosic sandstone 

that “... intertongues with ... the Red Desert, Niland, and Cathedral Bluffs tongues of the Wasatch 

Formation, and the Lumen and Tipton tongues and Laney Shale Member of the Green River Formation” 

(Pipiringos 1961). Love and Christiansen (1985) mapped Battle Spring rocks as far south as I-80 west of 

Rawlins, and included in it several hundred feet of gray, green, gold, and red mudstones, thin arkosic 

ribbon sandstones, and carbonaceous shales. No fossil vertebrates have been reported from Battle Spring 

rocks within the project area; however, bone fragments, including one of a fossil bird, were found in red 

mudstones (paleosols) during a reconnaissance survey for this study. 

3.3 SOILS 

Soils in the CD-C project area vary widely, but are predominantly formed from residuum on bedrockcontrolled uplands and alluvium in playas (BLM 1999). Residuum refers to unconsolidated, weathered, or 

partly weathered mineral material that accumulates by disintegration of bedrock in place. Variable 

average annual precipitation patterns exist across the project area, with three different precipitation 

gradients that range from 7 to 9, 10 to 14, and 15 to 19 inches. The project area is dominated by the 10- to 

14-inch precipitation zone with the northwest corner of the project area in the 7- to 9-inch precipitation 

3-18 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
CHAPTER 3—AFFECTED ENVIRONMENT—SOILS 

zone and a small portion in the southeast area in the 15- to 19-inch precipitation zone (Texas Resource 

Consultants [TRC] 1981; Wells et al. [Wells] 1981). 

Two Order 3 soil surveys were previously completed by the BLM in cooperation with the Soil 

Conservation Service [now known as the Natural Resources Conservation Service, NRCS] for most of the 

CD-C project area (TRC 1981; Wells et al. 1981). For areas not covered by the existing soil surveys, 

Order 3 field mapping was completed by KC Harvey Environmental, LLC during May 2007. During the 

field mapping, existing soil-mapping units from the TRC and Wells 1981 surveys were extended into the 

unmapped areas of the project area using aerial imagery. The proposed soil map unit boundaries in the 

unmapped areas were then verified in the field by sampling the soils to a depth of 60 inches with a 

Giddings probe (Giddings Machine Company, Colorado). 

A total of 387 soil complexes, associations, taxadjuncts, and variant map units occur within the 1,070,086 

acres that comprise the CD-C project area. A total of 286 soil series comprise the 387 map units. 

The majority of the project area is used as rangeland for domestic livestock grazing, wildlife habitat, and 

recreation. A small portion of the area is used for production of native hay, both irrigated and dryland, 

and utilization of wood for fence posts and firewood (TRC 1981; Wells et al. 1981). Since the 1950s, 

development of the area’s natural gas resources has become a major land use. 

3.3.1 General Description of Major Soil Types 

Soils in the project area were formed from erosion of bedrock exposed at the surface and from lacustrine, 

alluvium, loess, and eolian deposits (BLM 1999). The parent material in the project area is dominated by 

tertiary shales and sandstones and uplifted cretaceous sedimentary rock (Munn and Arneson 1998). Soils 

on the tertiary bedrock are poorly developed with little clay accumulation. Sandy soils occur on stabilized 

sand dunes and in areas with active dunes. Saline soils exist in playas, and sodic soils occur on alluvial 

fans derived from high-sodium parent materials. The project area contains soil orders of alfisols, 

inceptisols, mollisols, and aridisols. All soils within the project area have a frigid temperature regime. 

Soil texture is a mix of fine-loamy, coarse-loamy, and sandy materials. Slopes are generally level to 

undulating (zero–10 percent) and are separated by areas with steeper slopes (10–40 percent) to vertical 

slopes (rock outcrops). 

3.3.2 Soil Limitations 

To assess the potential limitations of the CD-C project area soils, five areas of concern were addressed: 

water erosion, wind erosion, runoff potential, local road construction limitations, and reclamation 

potential. These were evaluated using soils information from the two soil surveys completed by the BLM 

(TRC 1981; Wells et al. 1981). Results are summarized in Table 3.3-1 and a discussion of each category 

is provided below. 

Information from individual soil map units was used to evaluate the soil limitations. If multiple soil series 

existed within a single map unit, rankings were assigned based on the soil series that comprised the 

greatest acreage within the unit. To provide the most unbiased ranking, assignments were made using the 

relative size of the included soil series rather than the most limiting or the least limiting soil series within 

the map unit. 

To ascertain the distribution of potential soil limitations for existing natural gas disturbances, the number 

of current wells drilled in each of the rating class areas for each limitation was determined. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 3-19 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

CHAPTER 3—AFFECTED ENVIRONMENT—SOILS 

Table 3.3-1. Potential soil limitations in the CD-C project area 

Potential Limitation Rating Class/Limiting 

Features Acres % Total Area % of Disturbance in Each Class2 

Water Erosion Slight 748,850 69.9 72.8 

Moderate 230,713 21.5 21.5 

Severe 45,808 4.3 3.0 

Not Rated / Water 45,552 4.3 2.8 

Wind Erosion Slight 100,534 9.4 13.6 

Moderate 859,633 80.3 77.7 

Severe 65,204 6.1 5.9 

Not Rated / Water 45,552 4.3 2.8 

Runoff Potential Low 19,686 1.8 0.5 

Low To Moderate 21,416 2.0 0.9 

Moderate 362,499 33.8 6.6 

Low to High 67,473 6.3 35.5 

Moderate to High 237,355 25.0 29.6 

High 299,336 28.0 24.6 

Not Rated / Water 33,158 3.1 2.3 

Road Construction 

Rationale1 

Moderate 680,344 63.5 63.8 

Moderate / Severe 703 0.1 0.0 

Severe 348,732 32.6 33.5 

Not Rated / Water 41,145 3.8 2.7 

Shallow to Bedrock 55,597 5.2 3.2 

Low Strength Soils Present 902,656 84.4 87.3 

Shrink-Swell Soils Present 8,544 0.8 1.3 

Soils Too Sandy 52,110 4.9 5.4 

Wet Conditions 9,671 0.9 0.0 

No Rationale 40,934 3.8 2.7 

Reclamation Potential 

Reclamation 

Rationale1 

Good 221,785 20.7 13.7 

Fair 269,565 25.2 26.2 

Poor 537,228 50.2 57.4 

Not Rated / Water 40,934 3.8 2.7 

High Soil Salinity Levels 449,199 42.0 54.4 

Large Stones Present 4,678 0.4 0.4 

Soils Too Clayey 288,034 26.9 23.0 

Soils Too Sandy 57,433 5.4 5.5 

Wet Conditions 4,972 0.5 0.0 

1

 For the Road Construction Limitation and Reclamation Rationale, the limiting features should not sum to the total project 

acreage, as a single soil could be limited by several of the features listed. 

2

 The percentage of disturbance in each class is estimated as the percentage of current wells located in each category. 

3-20 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
CHAPTER 3—AFFECTED ENVIRONMENT—SOILS 

3.3.2.1 Water Erosion 

To assess the potential for soil erosion caused by water, the soil erosion factor (K) obtained from data 

recorded by TRC and Wells in 1981 and soil slope data were used to rank the CD-C project area soils for 

susceptibility to erosion. Slope data were derived from the digital elevation model for the project area. 

The K indicates the susceptibility of a soil to sheet and rill erosion (Institute of Water Research 2002). It 

is one of the six factors used in the Revised Universal Soil Loss Equation to predict the average annual 

rate of soil loss by water erosion. The K is based on percentage of silt, sand, organic matter, soil structure, 

and hydraulic conductivity. The soil-surface horizon K was used to group the project area soils into 

water-erosion classes. 

The values for K factors and slope ranges used to group the soil into slight, moderate, and severe watererosion classes are provided in Table 3.3-2. The K value and percent slope data were queried to 

determine the surface area relative to the slight, moderate, and severe erosion classes. These data were 

plotted on Map 3.3-1 to illustrate the potential for water erosion in the CD-C project area. Overall, the 

susceptibility to water erosion is slight, with 748,850 acres or 69.9 percent of the project area rated as 

having slight water-erosion potential (Table 3.3-1). Only 4.3 percent of the project area, or 45,808 acres, 

is rated as having a severe water-erosion potential. The large percentage of area classified as having slight 

water-erosion potential is controlled by the flat slopes that occur throughout the project area. 

Table 3.3-2. Water erosion classes determined by Erosion Factor (K) and Slope in the CD-C project 

area 

Erosion Factor (K) 

Water Erosion Class 

Slight Moderate Severe 

Slope (%) 

<0.2 <20 20 to 40 >40 

0.2 to 0.32 <15 15 to 35 >35 

>0.32 <10 10 to 20 >20 

At present 72.8 percent of the total wells currently drilled within the CD-C project area are located within 

soils that have a slight risk for water erosion. 

3.3.2.2 Wind Erosion 

To assess the potential of soil erosion by wind, the wind-erodibility class was obtained from data recorded 

by Texas Resource Consultants (1981) and Wells et al. (1981). Wind-erodibility groups are made up of 

soils that have similar properties affecting their resistance to wind erosion in cultivated areas. Soils are 

grouped according to percent sand, silt, and clay; calcium carbonate content; presence of surficial coarse 

fragments; and surface-wetness conditions. 

The potential for wind erosion in the CD-C project area is shown on Map 3.3-2. Soils within the 1 and 2 

wind-erodibility groups are classified as a severe limitation for wind erosion; soils in the 3, 4, and 4L 

wind-erodibility groups are considered as a moderate limitation for wind erosion; and soils in the 5, 6, 7, 

and 8 wind-erodibility groups have a slight limitation for wind erosion (TRC 1981, Wells et al. 1981). A 

moderate limitation because of wind erosion exists for 80 percent of the total project area or 859,633 

acres (Table 3.3-1). Only 9.4 percent or 100,534 acres and 6.1 percent or 65,204 acres, respectively, are 

rated to have slight and severe limitations to wind erosion, respectively. 

At this time, 78 percent of the total wells currently drilled within the CD-C project area are located within 

soils that have a moderate limitation for wind erosion. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 3-21 
CHAPTER 3—AFFECTED ENVIRONMENT—SOILS 

Map 3.3-1. Water-erosion potential for the CD-C project area 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

3-22 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
CHAPTER 3—AFFECTED ENVIRONMENT—SOILS 

Map 3.3-2. Wind-erosion potential for the CD-C project area 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 3-23 
CHAPTER 3—AFFECTED ENVIRONMENT—SOILS 

3.3.2.3 Runoff Potential 

To assess the potential for surface runoff, the hydrologic soil group was obtained from Texas Resource 

Consultants (1981) and Wells et al. (1981). The hydrologic soil group classifies soils according to their 

runoff-producing characteristics, which include depth to the water table, infiltration rate, permeability 

after prolonged wetting, and depth to the lowest permeable layer. Also, site-specific factors relating to 

management practices are considered, such as compaction, crusting, organic matter, and vegetative cover. 

The hydrologic group rating only considers the potential for runoff when soils are thoroughly wet and 

does not consider the slope of the soil. 

The potential for surface runoff in the CD-C project area is shown on Map 3.3-3. Soils within Hydrologic 

Soil Group A are considered to have a low runoff potential, Hydrologic Soil Group B soils have a 

moderate runoff potential, and Hydrologic Soil Groups C and D soils are considered to have a high runoff 

potential. Surface-runoff potential was predominantly moderate, composing 34 percent of the project area 

or 362,499 acres (Table 3.3-1). A rating of high runoff potential was given to 299,336 acres or 28 percent 

of the CD-C project area. 

At this time, 36 percent of the total wells currently drilled within the CD-C project area are located within 

soils that have a moderate runoff potential. 

3.3.2.4 Road Construction 

To assess the degree of limitation to the construction of roads, unsurfaced road ratings were obtained 

from TRC (1981) and Wells et al. (1981). Road rankings were based on depth to bedrock, soil strength, 

shrink/swell potential, soil texture, large surface stones, slope, and surface wetness. 

The potential limitation for the construction of roads in the CD-C project area is shown in Map 3.3-4. 

The CD-C project area is predominantly rated as having a moderate limitation for road construction, with 

63.5 percent, or 680,344 acres, having this rating (Table 3.3-1). The limiting features to road construction 

are provided in Table 3.3-1. Soil strength, depth to bedrock, and sandy soil textures are the main 

limitations to construction in the CD-C project area. 

At present, 64 percent of the total wells currently drilled within the CD-C project area are located within 

soils that have moderate limitations to road construction. 

3.3.2.5 Reclamation Potential 

Reclamation is the reconstruction of topographic, soil, and plant conditions following disturbance to 

allow the area to fully function as part of the ecosystem (Munshower 1994). The BLM’s long-term 

objective of final reclamation is to set the course for eventual ecosystem restoration, including the 

restoration of the natural vegetation community, hydrology, and wildlife habitats. In most cases, this 

means returning the land to a condition approximating or equal to that which existed prior to the 

disturbance. The Operator must achieve short-term stability, visual, hydrological, and productivity 

objectives of the surface-management agency and must take steps to ensure long-term objectives will be 

reached though natural processes (USDI and USDA 2006). 

To determine reclamation potential of the CD-C project area soils, the topsoil rating presented in the soil 

surveys prepared by Texas Resource Consultants (1981) and Wells et al. (1981) was used as a direct 

correlation of the soil reclamation potential. Soils having good, fair, or poor topsoil ratings are classified 

on Map 3.3-5 as having good, fair, and poor reclamation potential, respectively. The soil classifications 

defined in the soils survey are influenced by many factors such as rainfall, slope, and aspect in addition to 

the physical and chemical composition of the soil. The direct correlation used between topsoil rating and 

soil reclamation potential indirectly considers the factors that would be favorable or unfavorable for soil 

reclamation. 

3-24 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
CHAPTER 3—AFFECTED ENVIRONMENT—SOILS 

Map 3.3-3. Runoff potential in the CD-C project area 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 3-25 
CHAPTER 3—AFFECTED ENVIRONMENT—SOILS 

Map 3.3-4. Potential road construction limitations in the CD-C project area 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

3-26 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
CHAPTER 3—AFFECTED ENVIRONMENT—SOILS 

Map 3.3-5. Reclamation potential for soils in the CD-C project area 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 3-27 
CHAPTER 3—AFFECTED ENVIRONMENT—SOILS 

The reclamation potential of the CD-C project area is primarily poor, with 537,228 acres or 50 percent of 

the total project acreage having this rating (Map 3.3-5, Table 3.3-1). Locations identified as “No Rating” 

on Map 3.3-5 generally consist of rock outcrops or rock surfaces that did not include a topsoil rating since 

topsoil is not present in these locations. 

Rankings of fair and good were given to 25 percent or 269,565 acres, and 21 percent or 221,785 acres of 

the CD-C project area, respectively. The limiting features to reclamation are provided in Table 3.3-1. 

Saline/sodic soil conditions and either clayey or sandy soil textures are the main limitations to 

reclamation of the CD-C project area. 

At this time, 57 percent of the total wells currently drilled within the CD-C project area are located within 

soils that have poor reclamation potential. For the currently drilled well locations with limitations to 

reclamation, the main limitation to reclamation is saline/sodic soil conditions. 

3.3.3 Watershed-Based Land Health Assessment 

In 2008 the RFO finished conducting Standards and Guidelines Assessments for all the watersheds within 

the field office. These are watershed-based land health assessments mandated by the Director of the BLM 

on a 10-year basis. From 1998 through 2000, the RFO conducted Standards and Guidelines Assessments 

on an allotment basis; however, in 200, in order to meet this 10-year timeframe, larger-scale watershedbased reports were undertaken. The Upper Colorado River and the Great Divide Basin were the first two 

watershed reports completed (2002 and 2003, respectively), and are due for reassessment over the next 

three years, at which time progress towards management objectives will be evaluated. Standard 1 – 

Watershed Health, states that “[w]ithin the potential of the ecological site (soil type, landform, climate, 

and geology), soils are stable and allow for water infiltration to provide for optimal plant growth and 

minimal surface runoff” (BLM 2001a). Standard 1 is considered met if upland soil cover generally 

exceeds 30 percent and obvious signs of soil erosion are not apparent, and if stream channels are stable 

and improving in morphology. Key watershed health-related issues identified by the Standards and 

Guidelines Assessment for the Upper Colorado River and Great Divide Basin include erosion from 

improved and unimproved roads, and short- and long-term erosion from oil and gas field development. 

During the 2001 field season, project area watersheds within the Upper Colorado River Basin were 

assessed (BLM 2002). Barrel Springs Draw, a sub-watershed within the Muddy Creek watershed, and the 

Lower Sand Creek sub-watershed within the Little Snake River watershed, were determined to meet 

Standard 1. The Upper Muddy Creek and Lower Muddy Creek sub-watersheds within the Muddy Creek 

watershed did not meet Standard 1. Holler Draw and Chicken Springs Wash in the Upper Muddy Creek 

watershed (2,500 acres), and Little Robber and Cottonwood Creek in the Lower Muddy Creek watershed 

(6,000 acres) have large, active head-cuts caused by gradient readjustment processes; therefore, because 

the stream channels are not stable, these areas did not meet Standard 1. 

During the 2002 field season, project area watersheds within the Great Divide Basin were assessed (BLM 

2003). All sub-watersheds, including Battle Springs Flat, Buck Draw, Cyclone Draw, Latham Draw, Red 

Creek, Red Desert Basin, Red Wash Draw, Salt Sage Draw, and Upper Separation Creek were determined 

to meet Standard 1. 

3-28 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
CHAPTER 3—AFFECTED ENVIRONMENT— WATER RESOURCES
 

3.4 WATER RESOURCES 

Water resources in the CD-C project area include both surface water and groundwater. A majority 

(approximately 70 percent) of the project area is located within the Great Divide Basin (hydrologic unit 

code [HUC] 14040200). Approximately 29 percent of the project area is within the White-Yampa Basin 

(HUC 140500) and 1 percent is within the Upper Green Basin (HUC 140401). Watershed basins within 

the project area are shown on Map 3.4-1. Surface water in the Great Divide Basin drains internally, with 

no surface hydrologic outlet. The Upper Green and White-Yampa watersheds are part of the Upper 

Colorado Basin (HUC 14). 

Groundwater resources in the project area include unconfined (water table) and confined aquifers. The 

unconfined aquifers are generally shallow, blanket-type deposits of Quaternary or Tertiary age and are 

generally found within 400–600 feet of the ground surface. Alluvial deposits fall into this category. 

Confined aquifers are bound by relatively impermeable rocks and are generally in the deeper formations, 

such as the Mesaverde Group. Most of the geologic formations of pre-Oligocene age in the project area 

contain water under confined pressure (Welder and McGreevy 1966). Conventional oil and gas wells 

would be completed in the Almond Formation in the Mesaverde Group at depths between 8,000 and 

12,000 feet. Coalbed natural gas (CBNG) development, if undertaken, would primarily target the Fort 

Union Formation with secondary reserves targeted in the Wasatch, Frontier, and Lance formations at 

depths between 550 and 7,700 feet. 

3.4.1 Climate and Precipitation 

Climate and precipitation, as detailed in Section 3.5 (Air Quality), greatly influence the character and 

condition of the surface and groundwater resources. The project area is located in a continental dry, coldtemperature-subarctic climate (Trewartha 1968). The climate is characterized by precipitation deficiency, 

where potential evaporation exceeds precipitation. Temperatures are generally cold, with fewer than eight 

months of the year having an average temperature greater than 50° F. Summer days are warm, summer 

nights are cool, and winters are cold. Strong and prolonged winds periodically sweep the project area 

throughout the year, being especially prevalent in winter. 

These climatic conditions (low precipitation and high evaporation rates) result in the prevalence of 

surface water features in the project area with ephemeral or intermittent flows. The climatic conditions are 

reflected in the limited amount of shallow groundwater and the prevalence of confined aquifer systems. 

Recharge to the groundwater systems generally occurs at higher, distant elevations, with limited local 

recharge to the shallow aquifers. 

3.4.2 Surface Water 

There are three major drainage basins associated with the project area (Map 3.4-1). The Continental 

Divide runs east and west across the central portion of the project area. Drainages in the project area south 

of the Continental Divide flow into the Upper Green Basin or the White-Yampa Basin. Tributaries to 

Bitter Creek drain the portion of the project area within the Upper Green Basin. Bitter Creek flows to the 

Green River, which flows to the Colorado River, and ultimately to the Pacific Ocean. Tributaries to the 

Little Snake River drain the portion of the project area within the White-Yampa Basin. The Little Snake 

River flows to the Yampa River, which flows southwest to its confluence with the Green River in 

Colorado. Drainage north of the Continental Divide is contained in the Great Divide Basin. As mentioned 

above, the Great Divide Basin is internally drained, with no surface hydrologic outlet. 

Just over 1 percent of the project area is within the Upper Green Basin. Tributaries to Bitter Creek (Red 

Wash and Laney Wash) begin in the project area and flow out of the area to the southwest (Map 3.4-1). 

Surface water hydrology data are limited for the portion of the project area within the Upper Green Basin 

due to the dry nature of the climate and resulting minimal stream-flow in the area. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 3-29 
CHAPTER 3—AFFECTED ENVIRONMENT—WATER RESOURCES 

Map 3.4-1. CD-C project area with watershed basins and streams 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

3-30 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
CHAPTER 3—AFFECTED ENVIRONMENT—WATER RESOURCES 

Very small portions of the White-Yampa Basin within the project area are drained by Willow 

Creek/Shallow Creek (tributaries to Sand Creek) and the North Prong of Red Creek. The remainder of the 

White-Yampa Basin within the project area is drained by Muddy Creek and its tributaries. Muddy Creek 

is the dominant water feature within the project area and it flows into the perennial Little Snake River, 

immediately south of the project area (Map 3.4-1). 

Most surface water flow within the Great Divide Basin is ephemeral (occurring only in response to 

localized rainfall or snowmelt) or intermittent (flowing water during certain times of the year, when 

groundwater provides water for stream flow). The only streams in the Great Divide Basin with perennial 

flow are the upper portion of Separation Creek, in the Atlantic Rim area, and Lost Soldier Creek, in the 

Green Mountain area. Lost Soldier Creek is not within the project area. A majority (approximately 85 

percent) of the Great Divide Basin drainage area within the project area drains internally, not leaving the 

project area. Approximately 10 percent of the Great Divide Basin drainage area within the project area 

receives run-on from other areas in the basin (Bear Creek, Red Creek, Lost Creek, and Stewart Creek to 

the north, and Smiley Draw to the west). Surface water from the remaining 5 percent of the project area in 

the Great Divide Basin drains to the east off the project area by way of Creston Draw, Buck Draw, and 

Fillmore Creek, which are tributaries to Separation Creek. Major surface water features within the Great 

Divide Basin associated with the project area are shown on Map 3.4-2. 

3.4.2.1 Surface Water Location and Quantity 

Detailed information regarding surface water quantity within the project area is provided in Appendix F, 

Water Resources Supplemental Data. Historic flow data are available near the project area from one 

station on Muddy Creek (U.S. Geological Survey [USGS] Station 09259000) and one station on the Little 

Snake River (USGS Station 09257000). Current flow data are available from one station, monitored 

between 2004 and the present, on Muddy Creek (USGS Station 09258980). Historic flow data in the 

Great Divide Basin are available near the project area from two stations on Separation Creek (USGS 

Stations 09216525 and 09216527). Although all five of these stations are outside of the project area, they 

represent the nearest USGS flow monitoring stations. 

Upper Green Basin 

A very small portion of the project area drains into the Upper Green Basin (Map 3.4-1). Less than one 

percent of the project area is drained by tributaries to Bitter Creek (HUC 14040105). Bitter Creek is a 

perennial stream that flows into the Green River approximately 50 miles west of the project area. 

Historical flow data (1975-1981) are available from one monitoring station on Bitter Creek (USGS 

Station 09216545). Flow data from this station varied widely, from zero to 333 cubic feet per second 

(cfs). 

White-Yampa Basin 

Approximately 29 percent of the project area is drained by the White-Yampa Basin (Map 3.4-1). 

Watersheds within the White-Yampa Basin that are associated with the project area include the Muddy 

Creek Sub-basin (HUC 14050004) and the Little Snake Sub-basin (HUC 14050003). 

Muddy Creek begins in the Sierra Madre Range, east of the project area. Muddy Creek and its ephemeral 

tributaries, including Barrel Springs Draw (and its tributaries North Barrel Springs Draw and Windmill 

Draw), Blue Gap Draw, Robbers Gulch, and Red Wash, are included in this sub-basin. Muddy Creek 

flows west to Wyoming State Highway (WY) 789, where it enters the project area. It then flows south, 

meandering in and out of the project area, to its confluence with the Little Snake River near Baggs, 

Wyoming, approximately 6 miles south of the project area (Map 3.4-1). The Muddy Creek watershed 

encompasses approximately 1,200 square miles (mi2

) and ranges in elevation from about 6,300 to about 

8,200 feet. 

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CHAPTER 3—AFFECTED ENVIRONMENT—WATER RESOURCES 

Map 3.4-2. CD-C project area surface water features 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

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CHAPTER 3—AFFECTED ENVIRONMENT—WATER RESOURCES 

Muddy Creek is a high-elevation, cold-desert stream. Streamflow varies with location along the drainage. 

Muddy Creek exhibits perennial flow for the majority of its length, and in some years flows intermittently 

because of irrigation water removal south of the George Dew/Red Wash wetlands complex. In years with 

high runoff amounts, Muddy Creek flows perennially throughout its length. Snowmelt (typically March to 

mid-June) produces significant runoff from higher elevations of the watershed, east of the project area. 

The intermittent stream flow that is present in some reaches below the George Dew/Red Wash wetlands 

complex is due to contributions from springs, seeps, and flowing wells. High-flow events can occur in 

response to precipitation events during the summer and fall months. 

Flow in the tributaries to Muddy Creek is predominantly ephemeral, responding to localized snowmelt 

and rainfall events, but tributaries may also experience some intermittent flow due to contributions from 

springs and seeps. Tributary channels are generally dry and prone to flashy, periodic flood events from 

isolated thunderstorm systems from May to October. 

Beatty (2005) divided Muddy Creek into two major segments: upper Muddy Creek and lower Muddy 

Creek (Map 3.4-1). The upper segment is identified as that portion of the watershed upstream of a large 

headcut stabilization structure that is located in Section 11, T17N: R92W. This structure is located just 

downstream of where Muddy Creek crosses the ARPA boundary and just upstream of where Muddy 

Creek crosses WY 789 (Map 3.4-1). The four primary tributaries mentioned above are within the lower 

segment, which extends from the large headcut stabilization structure to the Little Snake River 

confluence. Lower Muddy Creek is highly erosional and has abundant channel incisions (Beatty 2005). 

Channel substrates in the lower segment consist of very fine-grained sediments (sands, silts, and clays). A 

large wetland complex (George Dew/Red Wash) occurs on the reach of Muddy Creek that lies west of 

WY 789 (Map 3.4-2). This wetland area consists of impoundments, artificially constructed channels, 

vertical drop structures, headgate structures for water diversion, overflow spillways, and a braided streamchannel network. 

The historical mean flow rates at two USGS Stations (09259000 and 09258980) on Muddy Creek near 

Baggs were 14.8 cubic feet per second (cfs) and 18.0 cfs, respectively. Calculated median flows at the 

same two stations were 2.8 cfs and 1.1 cfs (USGS 2011a). Median flows are generally more 

representative of the central tendency of the data because outliers (highest and lowest flow rates) can 

dramatically impact the average whereas the median is less affected. Because precipitation varies 

significantly from year to year, annual runoff values can vary significantly. Based on the 1,200 mi2 

drainage area and a 2004-2010 average annual runoff of 14,360 acre feet per year, the unit runoff for the 

Muddy Creek at USGS Station 09258980 is about 0.2 inch per year (USGS 2011a). 

The Upper Muddy Creek Watershed/Grizzly Wildlife Habitat Management Area (Grizzly WHMA) is 

located primarily east of the CD-C project area (Map 3.9-5). The western-most portion of the Grizzly 

WHMA lies within the CD-C project area. The WHMA consists of 59,477 acres of public lands surface in 

a checkerboard pattern. The goal of the WHMA is to “manage habitat for the Colorado River fish species 

unique to the Muddy Creek watershed” (BLM 2008a). In the Grizzly WHMA, the WGFD has been 

working with the BLM, the grazing permittee, and the Little Snake River Conservation District (LSRCD) 

to implement similar measures. According to the Rawlins RMP, the area is open to oil and gas leasing 

with intensive management of surface-disturbing and disruptive activities (BLM 2008a). 

Willow Creek/Shallow Creek (tributaries to Sand Creek) and the North Prong of Red Creek are drainages 

in the Little Snake Sub-basin that drain a small portion of the project area. Sand Creek and the North 

Prong of Red Creek flow into the Little Snake River approximately 8 miles from the southwest corner of 

the project area boundary (Map 3.4-1). Willow Creek/Shallow Creek and the North Prong of Red Creek 

are unclassified ephemeral drainages. No flow data are available for Willow Creek or the North Prong of 

Red Creek. The Little Snake River originates in the Sierra Madre Range and flows southwest into 

Colorado. The historical (1910–1923 and 1938–1971) mean flow rate at USGS Station 09259000 on the 

Little Snake River near Dixon was 514.3 cfs. Calculated median flow at the same station was 100.0 cfs 

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CHAPTER 3—AFFECTED ENVIRONMENT—WATER RESOURCES 

(USGS 2011a). Because precipitation varies significantly from year to year, annual runoff values can vary 

significantly. Based on the 988 mi2

 drainage area above USGS Station 0925700 and a 1911-1971 average 

annual runoff of 372,355 acre feet per year, the unit runoff for the Little Snake River at USGS Station 

09257000 is about 7.1 inches per year (USGS 2011a). 

Great Divide Basin 

The northern 70 percent of the project area is within the Great Divide Basin, a closed basin that is 

bounded by the Continental Divide on all sides and has no surface hydrologic outlet (USGS 1976; Seaber 

et al. 1987). The Great Divide Basin is a relatively shallow depression with isolated buttes, pan-like 

depressions, and sparse vegetation. In general, streams within the Great Divide Basin are ephemeral, but 

can be intermittent in sections (Lowham et al. 1976). The only streams in the Great Divide Basin with 

perennial flow are the upper portion of Separation Creek, in the Atlantic Rim area and Lost Soldier Creek, 

in the Green Mountain area. Numerous ephemeral streams flow toward the center of the Basin and 

terminate in natural or artificially constructed impoundments or disappear due to losses to diversions, 

evaporation, and/or infiltration (seepage). There are some spring-fed systems such as the Battle Springs 

Flat and unique alkaline wetland systems around Chain Lakes. Since a majority of the project area is 

within the Great Divide basin and since it is a closed basin, a majority of the surface water flow 

originating in the CD-C project area terminates within the project boundary. 

The Chain Lakes wetlands are located in the north central portion of the CD-C project area (Map 3.4-2). 

They are managed cooperatively by the WGFD and BLM as the Chain Lakes WHMA. The Chain Lakes 

WHMA consists of 30,560 acres of public lands in a checkerboard pattern. This area is one of the lowest 

topographic regions (6,500 feet in elevation) within the Great Divide Basin, resulting in numerous 

shallow lakes that are alkaline due to the lack of external water outlets. The annual precipitation of less 

than 7 inches, high evaporative loss rates, and surface salt crusting also contribute to shaping this 

community. The lakes and adjacent moist soils support a variety of plant and animal species adapted to 

this environment. The goal of the Chain Lakes WHMA is to “manage the unique, fragile, and rare 

alkaline desert lake system and wildlife habitat values associated with the lake system” (BLM 2008a). 

According to the approved Rawlins Resource Management Plan (RMP), the area is open to oil and gas 

leasing with intensive management of surface disturbing and disruptive activities (BLM 2008a). 

While a majority of the surface water flow originating in the project area terminates within the project 

boundary, the majority of surface water leaving the project area in the Great Divide Basin flows into 

Separation Creek via Fillmore Creek and Creston Draw. Separation Creek flows adjacent to and east of 

the CD-C project area to Separation Lake. Separation Creek is, for most of its length, an ephemeral 

stream. It exhibits perennial flow in its upper reaches. Average flows documented at the two stations near 

Riner are 1.3 to 1.8 cfs. Estimated annual runoff volume for downstream reaches of Separation Creek is 

2,500 acre-feet (Larson and Zimmerman 1981). Fillmore Creek is an ephemeral stream (WDEQ 2001) 

that flows only in response to snowmelt or rainstorms, with snowmelt as the biggest contributor. Springs 

provide minor flow in the upstream reaches. 

Several other small ephemeral streams flow out of the project area but also have no outlets from the Great 

Divide Basin. 

Reservoirs, Lakes, and Ponds 

According to the Wyoming State Engineer’s Office (SEO) database, there are 286 reservoirs with valid 

water rights within the project area (SEO 2011). Approximately 96 percent (274) of these water bodies 

have an appropriated use of stock. Major reservoirs within the CD-C project area are shown on Map 3.4-

2. A complete list of valid surface-water rights associated with reservoirs, lakes, and ponds is included in 

Appendix F, Water Resources Supplemental Data. 

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CHAPTER 3—AFFECTED ENVIRONMENT—WATER RESOURCES 

Wetlands 

Wetlands are aquatic features defined as “those areas that are inundated or saturated by surface or 

groundwater at a frequency and duration sufficient to support, and that under normal circumstances do 

support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands 

generally include swamps, marshes, bogs, and similar areas” (33 CFR 328.3(b)). The prolonged presence 

of water creates conditions that favor the growth of specially adapted plants and promote the development 

of characteristic wetland (hydric) soils (EPA 2007). Vegetation in wetland environments is highly 

productive and diverse and provides habitat for many wildlife species. These systems as a whole play 

important roles in controlling floodwaters, recharging groundwater, and filtering pollutants (Niering 

1985). 

The U.S. Army Corps of Engineers (USACE) administers a regulatory program under Section 404 of the 

Clean Water Act (CWA), which requires a permit for the discharge of dredged or fill materials into 

Waters of the U.S. (WoUS), including jurisdictional wetlands. This regulatory program requires that an 

inventory of all WoUS, including wetlands, be performed; permits be acquired prior to dredging or filling 

jurisdictional wetlands; and impacts to jurisdictional wetlands and Other Waters of the U.S. (OWUS) be 

adequately mitigated. 

Formal wetland delineations have not been confirmed by the USACE for the project area. A preliminary 

evaluation of potential wetlands within the project area was completed using National Wetland Inventory 

(NWI) mapping. According to the NWI mapping, prominent natural wetland systems are found near 

internally drained sub basins in the northern portion of the project area within the Great Divide Basin 

(Hay Reservoir area, Lost Creek Basin, Battle Springs Flat, and Chain Lakes Flat) and artificially 

constructed/enhanced wetlands occur along Muddy Creek (George Dew/Red Wash wetland complex) in 

the southern portion of the project area (Map 3.4-2). There are also a large number of small wetlands 

linked to natural or artificially constructed impoundments throughout the project area. The vegetation 

types associated with riparian/wetlands habitats are discussed in Section 3.6.2.9. 

3.4.2.2 Surface Water Use 

As of February 2011, the SEO had a total of 383 permitted surface water rights on record within and 1 

mile adjacent to the project area (SEO 2011). Stock use was associated with 334 of the surface water 

rights. Surface water rights were also associated with irrigation (39), wetlands and fisheries (30), 

miscellaneous (13), reservoir supply (12), industrial/oil (10), domestic (7), temporary use (4), flow 

through non-consumptive (2), wildlife (2), flood control (1), recreation (1), and unspecified (1). The total 

for permitted uses exceeds the number of permitted surface water rights due to the fact that many of the 

surface water rights were permitted for multiple uses. A complete list of valid surface-water rights is 

included in Appendix F. 

WDEQ classifies Wyoming surface water resources according to the water body’s use designation. More 

detailed information regarding surface-water use classifications are presented in Appendix F. 

Ten lakes and reservoirs within the project area are classified for use by WDEQ (Map 3.4-2). None of the 

lakes or reservoirs in the project area are classified for outstanding value (Class 1). The highest 

classification on lakes and reservoirs within the project area is drinking water (Class 2AB). One reservoir 

(Little Robbers Gulch Reservoir) is within this classification. The highest classification for five of the 

lakes/reservoirs is fish consumption (Class 3A). The highest use classification for the remaining four 

water bodies is other aquatic life (Class 3B). 

Seventeen streams and springs within the project area and two near the project area are classified by the 

WDEQ. None of the streams in or near the project area are classified for outstanding use (Class 1). The 

Little Snake River, located near the project area, is classified for use as drinking water (2AB). The highest 

classification for two streams within or near the project area is non-game fish (2C). The highest 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 14, 2012 3-35 
CHAPTER 3—AFFECTED ENVIRONMENT—WATER RESOURCES 

classification for 14 of the 19 streams/springs is other aquatic life (Class 3B). The highest classification 

for the remaining two streams is for non-aquatic life use (Class 4B/C). 

3.4.2.3 Surface Water Quality 

In the arid high plains of southwestern Wyoming, surface-water quality, like stream flow, is variable both 

spatially and temporally. Perennial stream water is generally of better quality than that of the ephemeral 

and intermittent streams. The quality of runoff is largely dependent upon the amount of salts, sediments, 

and organic materials that accumulate in dry stream channels between periods of runoff. Factors that can 

govern the amount of buildup of these materials are a basin’s physical characteristics, land uses, and 

season of the year. More detailed information regarding water quality is presented in Appendix F. 

According to Section 3.3 Soils, the project area contains many types of topsoil that are saline or sodic. 

These soils, when eroded as a result of runoff events, can make salt available for dissolution into surface 

waters. Approximately 70 percent of the entire project area was rated as having slight water erosion 

potential, approximately 22 percent had moderate water erosion potential, and just over 4 percent had 

severe water erosion potential (the remaining 4 percent was not rated). Nearly 73 percent of existing 

project area disturbance is located on lands with slight water erosion potential, nearly 22 percent on lands 

with moderate water erosion potential, and 3 percent on lands with severe water erosion potential (the 

remaining 3 percent was not rated) (Section 3.3.2 Soil Limitations). 

Various federal and state agencies (e.g., USGS, BLM, EPA, and WDEQ) have monitored surface-water 

quality in and around the project area. Surface water samples have been analyzed for physical and 

chemical properties, salinity, and major ions. From this pool of existing water quality data, representative 

surface-water quality data were selected for inclusion in this EIS based on selecting sites on significant 

surface water courses and the availability of multiple samples from a particular site. Surface water quality 

data were evaluated from ten water-quality monitoring stations. Detailed information regarding surfacewater quality within the project area is provided in Appendix F. 

Surface water quality information in the Upper Green and White-Yampa sub-basin is available near the 

project area from two stations on the Little Snake River (USGS Stations 09257000 and 09259050), four 

stations on Muddy Creek (USGS stations 09258900, 09258050, 09258980, and 09259000), one station on 

Lower Barrel Springs Draw (USGS Station 09216310), and one station on Bitter Creek (USGS Station 

09216545). Six of the seven sampling stations in the Upper Green and White-Yampa sub-basin are 

outside of the project area but indicate water quality of streams leaving the project area. Historic surfacewater quality data in the Great Divide Basin are available for Fillmore Creek (USGS Station 09219240), 

the Chain Lakes (Station 481), and Separation Creek (USGS Station 09216527). The first two sampling 

stations listed are within the project area. Separation Creek is adjacent to and east of the project area. 

Baseline Water Quality Data 

Baseline surface-water quality data at selected sites associated with the project area are presented in 

Table 3.4-1. 

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Table 3.4-1. Surface-water quality at selected sites associated with the CD-C project area 

Number of Samples2 

Ph, Standard Units 

Conductance, μmhos/cm (Mean) 

Conductance, μmhos/cm (Min)

Conductance, μmhos/cm (Max)

TDS (Mean)

TDS (Minimum)

TDS (Maximum)

Suspended Solids3 (Mean) 

Suspended solids3 (Minimum) 

Suspended Solids3 (Maximum)

Turbidity, NTU (Mean)

Calcium (Mean)

Magnesium (Mean) 

Potassium (Mean)

Sodium (Mean)

Bicarbonate (Mean) 

Little Snake River (09257000) 107 8.1 259(34) 82 460 158(9) 46 260 154(101) 4 1,180 13 30 8 2 11 1

Little Snake River (09259050) 100 8.1 366(90) 87 855 243(17) 87 540 228(25) 6 852 167 34 12 2 26 1

Muddy Creek 1 

(09258050) 19 8.2 879(15) 570 1,170 1,460 395 897 256(12) 12 1,370 56 95 39 4 43 n

Muddy Creek (09258900) 3 8.6 1,350(2) 600 2,100 913(2) 396 1,430 6,198(2) 195 12,200 1,260 54 44 7 200 3

Muddy Creek (09259000) 41 8.2 966(35) 529 1,790 346(1) 346 346 3,191(41) 7 22,500 nm 42 40 9 286 3

Muddy Creek 1 

(09258980) 76 8.3 1,763(76) 448 3,990 1,229(65) 267 2,810 324(62) 13 2,530 55 82 53 5 257 n

Lower Barrel Springs Draw (09216310) 

7 8.4 533(4) 340 1,000 619(1) 619 619 nm nm nm 17 28 2 5 205 5

Bitter Creek (09216545) 155 8.4 1,755(149) 280 4,500 1,289(78) 295 2,740 1,843(105) 22 21,900 305 40 27 3 348 3

Upper Fillmore Creek (09219240) 

1 7.7 700(1) 700 700 495(1) 495 495 141(1) 141 141 984 32 68 7 22 

Separation Creek (09216527) 45 8.2 1,089(39) 220 2,390 200(1) 200 200 490(1) 490 490 131 74 69 6 80 2

Chain Lakes, Hansen Lake (481) 

15 9.1 4,502(7) 1,800 11,350 4,465(8) 1,304 11,289 423 15 956 nm 13 8 13 1,604 1,4

1 Daily mean values analyzed through February 14, 2012. 2 nm = Not measured. Total number of grab samples analyzed; not every parameter was analyzed in every 

(34) - Number of samples analyzed for that parameter. sample. 3 All units are mg/L except as noted. Total concentration; except as noted here, all reported values represent dissolved

concentrations. Source: WRDS 2007, USGS 2012

NTU = Nephelometric Turbidity Units. 

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Surface water quality information in the Muddy Creek watershed was examined for this EIS at Muddy 

Creek (USGS Stations 09258050, 09258980, 09259000, and 09259050 stations) and Lower Barrel 

Springs Draw (USGS Station 09216310). The water quality was variable both spatially and temporally. 

Muddy Creek water quality was characterized by moderate conductance and total dissolved solids (TDS) 

concentrations. The predominant ions were sodium, sulfate, and bicarbonate. Lower Barrel Springs Draw 

had moderate conductance and TDS values. 

Water quality in the Little Snake River was characterized (based on analysis at USGS Stations 09257000 

and 09259050) by low conductance and TDS concentrations. The water type was calcium bicarbonate. 

Water quality in the Bitter Creek watershed (based on analysis at USGS Station 09216545) was variable. 

Conductance and TDS values for Bitter Creek tended to be higher than those levels seen at the other 

stations. 

Water quality in the Great Divide Basin was examined at three stations. Upper Fillmore Creek (USGS 

Station 09219240) had low conductance and TDS levels. Separation Creek (USGS Station 09216527) had 

variable conductance. TDS concentrations in Separation Creek were low. The Chain Lakes/Hansen Lake 

(WDEQ 481) had high conductance and high TDS levels. 

Surface waters associated with the project area had moderately to highly basic pH (7.7 to 9.1). Dissolved 

oxygen concentrations were moderate (5.2 to 11). Hardness values varied between soft in the Chain Lakes 

(67 mg/L CaCO3) to hard in Separation Creek (467 mg/L CaCO3). Alkalinity (as expressed as 

bicarbonate) varied from 68 mg/L in upper Fillmore Creek to 1,400 mg/L in Chain Lakes. 

Suspended solids concentrations were typically high in Muddy Creek and Bitter Creek. Suspended 

sediment concentrations, like TDS concentrations, were greater in the ephemeral and intermittent streams 

than the perennial Little Snake River. The mean suspended solid concentrations in the Great Divide Basin 

ranged between 141 mg/L (Upper Fillmore Creek) and 490 mg/L (Separation Creek). 

Turbidity values were consistent with the suspended solids concentrations. Muddy Creek and Bitter Creek 

had turbidity of up to 1,260 and 305 nephelometric turbidity units (NTUs). The Little Snake River 

showed turbidity of up to 167 NTUs. Lower Barrel Springs Draw and Upper Fillmore Creek showed 

turbidity less than 100 NTUs. Turbidity at Separation Creek was 131 NTUs. 

The ionic composition of the various surface water bodies associated with the project area was variable. 

Major ion characterization of each surface water sample was compared. Bicarbonate was the dominant 

anion (negatively charged ion) in the Little Snake River, Lower Barrel Springs Draw, and the Chain 

Lakes. Sulfate was the dominant anion in Muddy Creek, Bitter Creek, Upper Fillmore Creek, and 

Separation Creek. Chloride was not dominant in any of the samples. Calcium was the dominant cation 

(positively charged ion) in the Little Snake River. Sodium was the dominant cation in Muddy Creek, 

Lower Barrel Springs, Bitter Creek, the Chain Lakes, and Separation Creek. Magnesium was high in 

Upper Fillmore Creek. 

Irrigation suitability of the streams as a function of sodium-adsorption ratio and salinity was examined for 

each stream sample. The Little Snake River, Muddy Creek, Lower Barrel Springs Draw, and Upper 

Fillmore Creek are in the C1-S2 category. C1-S2-categorized water can be used for all crops and soils 

where salt toxicity is concerned; however, the sodium may cause clay particles in irrigated soils to swell 

and disperse and thereby reduce the soil infiltration rate. Bitter Creek and Separation Creek are in the C2­

S1 category. C2-S1 water should be used with caution on moderately salt tolerant crops and should not be 

used on salt sensitive crops. Water from the Chain Lakes is categorized as C3-S2 water, indicating that 

crop production would suffer greatly if it were used for irrigation. 

Based on average values, Muddy Creek was moderately suitable as an irrigation-water supply where 

flows are available. The George Dew/Red Wash wetland complex is the primary location where Muddy 

Creek is used for irrigation (the wetland complex is formed by spreader dikes along Muddy Creek) (Maps 

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CHAPTER 3—AFFECTED ENVIRONMENT—WATER RESOURCES 

3.4-2 and 3.9-5). This area is primarily used for cattle and there is a diversion for small-scale bottomland 

irrigation along Muddy Creek. 

Salinity has become a major concern within the Colorado River drainage basin. The 1972 Clean Water 

Act required the establishment of numeric criteria for salinity for the Colorado River and in 1973, seven 

Colorado River basin states created the Colorado River Basin Salinity Control Forum. The Forum 

developed water quality standards for salinity including numeric criteria and a basin-wide plan of 

implementation. The plan consists of a number of control measures to be implemented by State and 

Federal agencies. In 1974, Congress enacted the Colorado River Basin Salinity Control Act. The Act was 

amended in 1984 to require the Secretary of Interior to develop a comprehensive program to minimize 

contributions from lands administered by the BLM. 

Selenium, like mercury and other metals, bioaccumulates in organisms at each trophic level. Aquatic life 

is exposed to selenium primarily through diet. Unlike mercury or PCBs, concentrations of selenium do 

not increase significantly in animals at each level of the food chain going from prey to predator (EPA 

2011b). The core regulatory guidelines for aquatic selenium pollution in the United States are the Aquatic 

Life Water Quality Criteria (Aquatic Life Criteria) derived by the U.S. Environmental Protection Agency 

(EPA) pursuant to the Clean Water Act (CWA) of 1977. The current aquatic life chronic criterion for 

selenium set by the EPA and WDEQ is 5 μg/L (EPA 2011b and WDEQ 2001). 

3.4.2.4 Water Bodies with Impairments or Threats 

The WDEQ evaluates streams periodically to determine what streams are threatened or impaired relative 

to the use classification. The current threatened and impaired streams are listed in Wyoming’s 2012 

305(b) Water Quality Assessment Report (WDEQ 2012). According to the assessment report, a portion of 

Muddy Creek (west of WY 789) is listed as threatened. No other surface water bodies in the project area 

are listed as threatened or impaired, although one other segment of Muddy Creek outside of the project 

area is listed as impaired due to exceedances of chloride and selenium criteria. 

According to WDEQ (2012), “Unstable stream channels and loss of riparian function have been 

identified as problems in much of the Muddy Creek Sub-basin,” in reference to Muddy Creek. The 

LSRCD, working through a Coordinated Resource Management (CRM) process with the BLM, 

landowners, grazing permittees, WGFD, and other stakeholders, addressed these water quality and 

riparian habitat problems. As part of the CRM process, LSRCD managed several Section 319 watershed 

improvement projects in the upper Muddy Creek drainage. Implementation measures included upland 

water development, cross fencing, and vegetation and grazing management. While the CRM process is no 

longer formally in place, the beneficial effects are still being realized. 

Within the project area, several projects have been designed for Muddy Creek to address physical 

(riparian condition and bank stability) degradation of the stream channel, which threatens its aquatic life 

support. Upstream of the project area reclamation measures included planting a variety of woody riparian 

vegetation to help stabilize streambanks, removal of a culvert on Muddy Creek, and restoration of 0.75 

mile of Muddy Creek in the upper watershed. According to WDEQ, results of this project showed 

considerable improvement to stream stability, aquatic habitat and riparian health, especially in the upper 

Muddy Creek tributaries (WDEQ 2012). 

Habitat degradation has been identified by the BLM and LSRCD as a serious water-quality concern on 

Muddy Creek from Red Wash (in the project area) downstream to the Little Snake River. According to 

WDEQ (2012), habitat degradation is likely caused by season-long riparian grazing that is exacerbated by 

accelerated erosion associated with oil and gas activities. WDEQ (2012) also states, “... projected 

increases in CBM [CBNG] development may lead to increased surface disturbance and increased erosion 

and sediment loading.” Several grazing management BMPs are being implemented in much of this lower 

watershed including changes in length, timing and duration of grazing, and cross-fencing. The Upper 

Muddy Creek Watershed/Grizzly WHMA is located in the north central portion of the CD-C project area. 

This WHMA was established with the goal to “manage habitat for the Colorado River fish species unique 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 3-39 
 

CHAPTER 3—AFFECTED ENVIRONMENT—WATER RESOURCES 

to the Muddy Creek watershed” (BLM 2008a). In the Grizzly WHMA, the WGFD has been working with 

the BLM, the grazing permittee, and the LSRCD to implement similar measures. 

3.4.2.5 Salinity Issues in the Colorado River Basin 

The southern 30 percent of the project area is located in the Colorado River Basin; as such, point-source 

discharge permits are regulated by the State of Wyoming in accordance with its adoption and 

incorporation into the Water Quality Rules and Regulations of the Colorado River Basin Salinity Control 

Forum (CRBSCF), which was established in 1973 (CRBSCF 2008). The CRBSCF is composed of 

representatives from each of the seven Basin states appointed by the governors of the respective states. 

The CRBSCF was created for interstate cooperation and to provide the states with the information 

necessary to comply with Section 303(a) and (b) of the Clean Water Act. In 1975, CRBSCF proposed, the 

states adopted, and the EPA approved water quality standards which included numeric criteria and a plan 

of implementation to control salinity increases in the Colorado River. The plan was designed to maintain 

the flow-weighted average annual salinity concentrations at or below the 1972 levels, while the Basin 

states continued to develop their compact-apportioned water supply (CRBSCF 2008). 

According to the CRBSCF, the focus for the implementation of salinity standards in the National 

Pollutant Discharge Elimination System (NPDES) permit program policy “shall be a no-salt return policy 

whenever practicable.” The NPDES Program policy (revised in 2002) states that the permitting authority 

may permit the discharge of salt from new industrial sources upon a satisfactory demonstration by the 

permittee that salt loading to the Colorado River from the new construction is less than one ton per day or 

366 tons per year, or the proposed discharge from the new construction is of sufficient quality in terms of 

TDS concentrations that the maximum TDS concentration is 500 mg/L for discharges into the Colorado 

River and its tributaries upstream of Lees Ferry, Arizona (CRBSCF 2008). In general, the salinity 

concentrations have decreased at the monitoring stations since the program was implemented (CRBSCF 

2008). 

As one of the seven member states of the CRBSCF, Wyoming regulates point discharge sources of 

salinity in the Wyoming portion of the Colorado River Basin through its Wyoming Pollutant Discharge 

Elimination System (WYPDES) permit program. The program is administered by the WDEQ/Water 

Quality Division (WQD) (WDEQ 1982). 

3.4.3 Groundwater 

The project area occurs in the Colorado Plateau and Wyoming Basin groundwater regions described by 

Heath (1984) and the Upper Colorado River Basin groundwater region described by Freethey (1987). 

More specifically, the project area is located over the Great Divide and Washakie structural basins in 

eastern Sweetwater and southwestern Carbon counties. The northern half of the project area is occupied 

by the Great Divide Basin and the southern half of the area is occupied by the Washakie Basin, with the 

Wamsutter Arch separating the two structural basins. Relatively recent studies by the USGS (Mason and 

Miller 2005; Bartos et al. 2006;) cataloged the groundwater resources within Sweetwater and Carbon 

counties, which include the Great Divide and Washakie structural basins. Groundwater resources include 

deep and shallow, confined and unconfined aquifers. Groundwater occurrence and flow in the project area 

are controlled largely by the geologic structure and precipitation in the area. Most of the saturated 

geologic units in the project area are heterogeneous, consisting of aquifers, semi-confining units, and 

confining layers. 

3.4.3.1 Groundwater Location and Quantity 

Welder and McGreevy (1966) reported that the geologic formations capable of producing the greatest 

quantities of water in the project area include the following: Quaternary alluvium; Tertiary deposits in the 

Wasatch and Fort Union Formations; Cretaceous units, including the Mesaverde Group and the Frontier 

and Cloverly Formations; the Sundance-Nugget Sandstone of the Jurassic age; and the Tensleep and 

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CHAPTER 3—AFFECTED ENVIRONMENT—WATER RESOURCES 

Madison Formations of the Paleozoic Era (Figure 3.1-1, Section 3.1.2). General aquifer characteristics 

are provided in Appendix F. Fisk (1967) estimated that the amount of moderately good-quality 

groundwater within the Great Divide Structural Basin was 500 million ac-ft and 300 million ac-ft. within 

the Washakie Structural Basin. The available data are not adequate for estimating the quantities of 

groundwater stored within the individual hydrogeologic units or the aquifer systems in the Green River 

Watershed Basin, which includes the Great Divide and the Washakie structural basins, but estimates of 

producible water volumes are available for the Tertiary formation beneath the Greater Green River Basin 

(Cleary et al. 2010). 

Quaternary aquifers in the Great Divide and Washakie basins are comprised of alluvial deposits along 

floodplains and isolated wind-blown and lake sediments. The Quaternary aquifers in the vicinity of the 

project area occur in alluvial deposits along Muddy Creek (Washakie Basin), in the Red Desert Flats area 

and around lakes (Great Divide Basin), and in wind-blown segments in the northwest and southeast of the 

project area. Groundwater flow within the sandy Quaternary aquifers is typically downward toward 

permeable underlying formations (Collentine et al. 1981). Intermittent drainages also often contain 

groundwater in the associated unconsolidated valley fills. Incised drainages serve as capture areas for 

wind-blown sand in reaches perpendicular to the prevailing winds. The sand-choked drainages favor rapid 

infiltration of rainfall and snowmelt, leading to contact springs and seeps where groundwater, perched in 

sandy surface deposits, escapes along contacts with less permeable bedrock. Thicknesses of Quaternary 

sediments range from zero to 70 feet. Well yields are typically less than 20 gallons per minute (gpm) 

(Welder and McGreevy 1966). 

“Minor” Tertiary aquifers in the project area occur in the Laney Member of the Green River Formation 

(mostly in the Washakie Structural Basin). “Major” Tertiary aquifers in the project area include the 

Wasatch, Battle Springs, and Fort Union (Washakie and Great Divide basins). Using nomenclature of 

Collentine et al. (1981), “minor” and “major” aquifers are characterized based on their relative waterbearing potential. Aquifers near the surface are recharged from direct downward percolation of 

precipitation and snowmelt and from seepage losses from streams. Deep aquifers are also recharged by 

these processes in outcrop and subcrop areas and from slow leakage from overlying and underlying 

aquifers. Thicknesses of Tertiary deposits vary from zero to more than 4,000 feet. Wasatch Formation 

wells yield up to 50 gpm. The Laney Member of the Green River Formation and the Battle Springs and 

Fort Union formations can yield hundreds of gpm to wells (Mason and Miller 2005; Bartos et al. 2006). 

There are six wells that are designated as municipal use and supply a public water system completed in 

Tertiary age aquifers (all in the Wasatch Formation) within the project area. These six wells are 

associated with water supply for the Town of Wamsutter. Using estimates of the volume of producible 

groundwater from Cleary et al. (2010), the volume of groundwater in the top 1,000 feet of the Tertiary 

formation under the project area is approximately 9.67 million ac-ft. Fisk (1967) estimated that the 

amount of moderately good-quality groundwater within the Great Divide Structural Basin was 500 

million ac-ft and 300 million ac-ft. within the Washakie Structural Basin. 

Upper Cretaceous aquifers include “minor” aquifers in the Lance and Fox Hills formations. “Major” 

aquifers of this period include the formations within the Mesaverde Group (Almond Formation, Ericson 

Formation, Rock Springs Formation, and Blair Formation in descending order), the Baxter Shale, and the 

Frontier Formation. The Mesaverde Group contains “major” aquifer units (the Almond Formation, Pine 

Ridge Sandstone, Allen Ridge Formation, and Haystack Mountains Formation), and is referred to as the 

Mesaverde Aquifer (Mason and Miller 2005; Bartos et al. 2006) in the Washakie and Great Divide basins. 

Due to water-quality variability, it is considered a groundwater source only near outcrop areas. Units 

within the Mesaverde Group yield natural gas to conventional gas wells in the area. In the Atlantic Rim 

area to the east, coal seams within the Almond Formation are the target of CBNG development. In areas 

where they occur, Upper Cretaceous strata range from a few hundred feet to 5,000 feet thick. Well yields 

from the “minor” aquifers are typically less than 25 gpm. Well yields of up to several hundred gpm are 

reported for the “major” aquifers (Welder and McGreevy 1966). 

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The Lower Cretaceous aquifers generally are deeply buried in the center of the Great Divide and 

Washakie basins, though these formations outcrop near the eastern edge of the project area. The lower 

Cretaceous strata consist of shale layers that act as regional aquitards or leaky confining layers (Mowry 

and Thermopolis shales). The Cloverly Formation is a “major” aquifer. Yields to wells range from 45 to 

240 gpm (Mason and Miller 2005; Bartos et al. 2006). There are no wells that are designated as a 

domestic use or as a municipal use and supply a public water system completed in Lower Cretaceous 

aquifers within the project area. 

The low-permeability Morrison Formation separates the Sundance-Nugget Aquifer of the Jurassic age 

from the Upper Cretaceous aquifers. The Jurassic-age Sundance-Nugget aquifer is comprised of 

permeable sandstone with minor quantities of shale, siltstone, and limestone (Collentine et al. 1981). The 

flow characteristics of the Sundance-Nugget aquifer are not well-defined. These aquifer units range from 

about 200 to 450 feet thick. Well yields are less than 35 gpm in the Sundance aquifer and up to 200 gpm 

in the Nugget aquifer (Mason and Miller 2005; Bartos et al. 2006). There are no wells that are designated 

as a domestic use or as a municipal use and supply a public water system completed in Sundance or 

Nugget aquifers within the project area. 

According to Collentine et al. (1981), two “important water-bearing intervals” occur in Paleozoic-Era 

rocks within the project area. The Pennsylvanian age Tensleep Formation consists of fine- to mediumgrained sandstone between confining layers of the Chugwater Formation (Triassic) and the Amsden 

Formation (Pennsylvanian) (Collentine et al. 1981). The Madison aquifer is comprised of limestone and 

dolomite bordered on the top by the fine-grained Amsden Formation and on the bottom by Cambrian 

rocks. Early Paleozoic rocks are notably absent from far southeast Wyoming and extremely thin on the 

west flank of the Sierra Madre uplift east of the project area. The zero isopach line for these Paleozoic 

units lies across and north of the Sierra Madre uplift indicating either non-deposition or erosion and 

complete removal of these units across the ancestral uplift prior to deposition of Mesozoic and Cenozoic 

age rocks. The truncated edge of Cambrian and Mississippian rocks lies east of the project area according 

to Blackstone (1963). Wells completed in the vicinity of the project area within both of these Paleozoic 

age aquifers, where present and of significant thickness, have demonstrated yields up to 400 gpm. There 

are no wells that are designated as a domestic use or as a municipal use and supply a public water system 

completed in Tensleep or Madison aquifers within the project area. 

3.4.3.2 Groundwater Use 

The SEO water rights database indicates that there are 1,081 groundwater wells permitted within or 1 

mile adjacent to the project area (SEO 2011). Permitted well uses include stock (294), miscellaneous 

(218), domestic (80), industrial (18), municipal (6), irrigation (5), and test wells (1). The total for 

permitted uses exceeds the number of well permits due to the fact that many of the wells are permitted for 

multiple uses. A complete list of valid groundwater rights is included in Appendix F. 

Other than designated land uses described above, little information is available on groundwater use 

specific to the Great Divide and Washakie structural basins. In 1981, total groundwater use in the Great 

Divide and Washakie basins was estimated by Collentine et al. (1981) at between 20,000 and 24,000 

acre-feet per year, approximately 30 percent of the total water use. More recent estimates of groundwater 

use are available on a county-wide basis. In 2000, Sweetwater County groundwater use was estimated at 

57,000 acre-feet per year, approximately 30 percent of the overall water used (Mason and Miller 2005). In 

2000, Carbon County groundwater use was estimated at 7,000 acre-feet per year, less than 2 percent of 

the overall water used (Bartos et al. 2006). 

3.4.3.3 Groundwater Recharge and Discharge 

Recharge to aquifers in the project area occurs by infiltration of precipitation on outcrop areas, infiltration 

of snowmelt runoff from the mountains, and seepage from streams and lakes. 

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CHAPTER 3—AFFECTED ENVIRONMENT—WATER RESOURCES 

Four major groundwater-recharge areas are identified in the Great Divide and Washakie structural basins. 

Three of these areas are outside of the project area near Rock Springs in Sweetwater County and the 

Atlantic Rim area in Carbon County. The fourth recharge area is the topographic high area around 

Creston Junction (Map 3.4-1). Piezometric levels in hydrogeologic units are higher in these four major 

recharge areas than other parts of the basin, probably because the higher altitude of these features results 

in slightly higher annual precipitation. Welder and McGreevy (1966) reported that most streams in the 

Washakie basin are “losing” streams, contributing to local groundwater recharge in the basin. The same is 

likely true for streams in the Great Divide Basin. Fisk (1967) estimated that the combined annual recharge 

for the Great Divide and Washakie structural basins was at 11,300 ac-ft. Section 4.9.3.1, Special Status 

Species, Proposed Action, includes a discussion of potential annual depletions to the Colorado River 

System. 

Aquifers in the Great Divide and Washakie structural basins are reported to be in direct hydraulic 

connection across the Wamsutter Arch. Recharge is reported to be at least 15 cfs in both basins. Due to 

the large groundwater storage capacity and the low recharge rate, estimates indicate that it would take 

more than 50,000 years to refill the fresh-water aquifers of the basins with groundwater if all of the 

groundwater was removed (Mason and Miller 2005; Bartos et al. 2006). 

In general, groundwater discharge from the aquifers throughout the project area occurs through seepage to 

streams and springs, discharge to wells, evaporation, and underground flow (Mason and Miller 2005; 

Bartos et al. 2006). According to Mason and Miller (2005), groundwater from the Mesaverde formation 

discharges to the Little Snake River, downstream of the confluence with Muddy Creek. Much of the 

deeper groundwater in the basins is artesian (i.e., having a static water level which rises to an elevation 

above the saturated zone). This results because the major recharge areas in the basins are exposed at 

higher elevations, putting the confined groundwater under hydraulic pressure. Water in a confined aquifer 

that is under hydraulic pressure will rise above the top of the aquifer when the overlying confining bed is 

pierced or broken, resulting in discharge from the confined aquifer (Mason and Miller 2005). The source 

of some of the water within the Chain Lakes surface water features in the Great Divide Basin is thought to 

be artesian groundwater that flows at the surface (WGFD 2008). 

3.4.3.4 Groundwater Flow Direction 

As discussed in Section 3.4.3.1, formations capable of producing the greatest quantity of water in the 

project area include the Quaternary alluvium, Tertiary deposits in the Wasatch and Fort Union 

Formations, Cretaceous units, including the Mesaverde Group and the Frontier and Cloverly Formations, 

the Sundance-Nugget Sandstone of the Jurassic age, and the Tensleep and Madison Formations of the 

Paleozoic Era. More detailed information regarding potentiometric surfaces of project area aquifers and 

groundwater flow are presented in Appendix F. 

The Quaternary aquifers consist of unconsolidated sand and gravel formations, mainly of alluvial origin, 

interbedded with lake and wind-blown sediments. The Quaternary alluvium is highly permeable, 

absorbing rainfall and stream flow, transmitting it downward to underlying formations. 

The groundwater flow direction in the Tertiary-aged Wasatch aquifer is from areas of recharge toward the 

basin center. In the Great Divide Structural Basin, Wasatch aquifer groundwater flows from the 

northwest, northeast, southwest, and southeast. In the Washakie Structural Basin, groundwater generally 

flows from west to east in the southern part of the Washakie Structural Basin. In the northern portion of 

the Washakie Basin groundwater motion is largely static. Some groundwater flows westward from the 

Washakie Structural Basin along Bitter Creek and southward along Muddy Creek. 

Groundwater flow direction for the Upper Cretaceous-aged aquifer within the Mesaverde Group is 

undefined in the northern part of the Great Divide Structural Basin. Groundwater within the aquifers of 

the Mesaverde Group is reported to flow from the Great Divide Basin toward the east, southeast, 

southwest, and west. In the Washakie Structural Basin, groundwater is reported to flow to the west and 

south (Mason and Miller 2005; Bartos et al. 2006). 

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Available potentiometric data are sporadic and could not be used to delineate flow patterns in the 

Sundance-Nugget aquifer. Potentiometric heads are highest in the uplift areas to the east, west, north, and 

northeast (Collentine et al. 1981). 

The groundwater flow direction for the Paleozoic-aged Tensleep aquifer is generally from the recharge 

areas along the northern and eastern flanks of the Great Divide Basin. Additional recharge into the 

Washakie Basin may occur to the south and east of the Rock Springs uplift. Tensleep aquifer groundwater 

flow is from the recharge areas toward the basin centers (Collentine et al. 1981). The groundwater flow 

direction for the Paleozoic-aged Madison aquifer is generally west, away from the outcrops (sources of 

recharge) towards the Great Divide and Washakie basin centers (Bartos et al. 2006). 

3.4.3.5 Groundwater Quality 

For the most part, comparisons between groundwater quality within the different structural features in the 

project area are difficult given the large variation in water quality within the features. In general, the 

quality of the groundwater underlying the Great Divide and Washakie basins is largely related to the 

depth of the aquifer, the type of strata in the saturated zone, the recharge rate and volume at the area 

sampled, and the residence time of the groundwater in the aquifer. Typically, quality of groundwater 

within a given hydrogeologic unit usually deteriorates with depth. 

Water-quality samples collected from wells and springs within Quaternary and Tertiary hydrogeologic 

units that were being used to supply water for livestock and wildlife were typically of good water quality 

(i.e. fresh water, see below). Wells that do not produce usable water are usually abandoned, and springs 

that do not produce usable water typically are not developed. In addition, where hydrogeologic units are 

deeply buried, they usually are not tapped for a water supply when a shallower supply is available. For 

these reasons the groundwater quality samples from the Quaternary and Tertiary hydrogeologic units are 

most likely biased toward better water quality and do not represent a random sampling of the units. 

Although the possible bias of these data does not allow for a complete characterization of the water 

quality of these hydrogeologic units as a whole, it probably allows for a more accurate characterization of 

the units in areas where they are shallow enough to be economically used. 

Most of the groundwater-quality samples used to characterize Mesozoic and Paleozoic hydrogeologic 

units came from the USGS Produced Waters Database (USGS 2011b). Although these samples were 

collected only where oil and gas production has taken place, they probably have less bias in representing 

ambient groundwater quality within hydrogeologic units developed as a result of this project than samples 

used to characterize Quaternary and Tertiary hydrogeologic units. 

Baseline groundwater-quality data (TDS and selenium) at selected aquifers associated with the project 

area are presented in Table 3.4-2. More detailed data regarding groundwater quality are presented in 

Appendix F. 

TDS concentrations in ground-water samples are classified according to the USGS salinity classification 

(Heath 1983) as follows: fresh, 0-1,000 mg/L; slightly saline, 1,000-3,000 mg/L; moderately saline, 

3,000-10,000 mg/L; very saline, 10,000-35,000 mg/L; and briny, more than 35,000 mg/L. 

TDS values for 18 samples collected in Quaternary aquifers in Sweetwater County ranged from fresh to 

very saline with the median value within the slightly saline range. In Carbon County, 32 samples 

collected from Quaternary aquifers varied from fresh to moderately saline with the median value within 

fresh range. 

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Table 3.4-2. Groundwater quality parameters for selected aquifers associated with the CD-C project area 

From Mason and Miller (2005) From Bartos et al. 2006 

Sweetwater Co. 

Quaternary

Aquifer

Sweetwater Co. 

Wasatch Aquifer 

Sweetwater Co. 

Mesaverde

Aquifer

Sweetwater Co. 

Nugget Aquifer

Sweetwater Co. 

Madison Aquifer 

Carbon Co.

Quaternary

Aquifer

Carbon Co.

Wasatch Aquifer 

Carbon Co.

Mesaverde

Aquifer

Carbon Co.

Nugget Aquifer

Carbon Co.

Madison Aquifer 

Sweetwater Co. 

Wasatch/Ft. Union 

Aquifer Produced 

Water 

# of Samples 18 80 30 -­ 17 32 11 130 15 11 -­ 

Parameter TDS (Median) (mg/L) 1,200 1,000 1,000 -­ 11,100 500 2,000 5,000 4,500 3,000 13,900 

TDS (Min) (mg/L) 500 150 200 3,000 3,820 30 700 250 1,500 150 1,050 

TDS (Max) (mg/L) 20,000 8,000 20,000 35,000 76,800 8,000 5,000 40,000 50,000 12,000 153,000 

Selenium (Median) (μg/L) 32.91 0.72 nm7 <13 nm 3.94 0.65 0.66 nm 1.43 nm 

Selenium (Min) (μg/L) 3.81 0.32 nm <13 nm <0.54 0.45 <0.36 nm 1.43 nm Selenium (Max) (μg/L) 1331 1.62 nm <13 nm 4.54 <0.75 0.86 nm 1.43 nm 

1 Based on 7 Samples 2 Based on 8 Samples 3 Based on 1 Sample 4 Based on 3 Samples 5 Based on 4 Samples 6 Based on 6 Samples 7 Not Measured. 

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CHAPTER 3—AFFECTED ENVIRONMENT—WATER RESOURCES 

TDS concentrations from 80 samples collected from the Wasatch aquifer (Tertiary age) in Sweetwater 

County ranged from fresh to moderately saline, with a median value within the fresh/slightly saline range. 

TDS values for 11 samples collected in Carbon County ranged from fresh to moderately saline, with a 

median value within the slightly saline range. TDS values from samples collected in Sweetwater County 

of water produced by oil and gas extraction from the Wasatch/Fort Union formations ranged from slightly 

saline to briny. TDS values of produced water from the Wasatch aquifer above 60,000 mg/L occurred at 

depths greater than about 2,500 feet below ground surface (Mason and Miller 2005). 

TDS concentrations in 30 samples collected in Sweetwater County from the aquifers of the Mesaverde 

group ranged from fresh to very saline, with a median value within the fresh/slightly saline range. TDS 

from 130 samples collected in Carbon County from the aquifers of the Mesaverde Group ranged from 

fresh to briny. TDS in 221 samples of water from oil and gas production in the Mesaverde ranged from 

slightly saline to briny with a median value within the very saline range. 

TDS concentrations from samples collected from the Nugget aquifer in Sweetwater County ranged from 

slightly/moderately saline to very saline/briny. TDS values for 15 samples collected in Carbon County 

ranged from slightly saline to briny, with a median value within the moderately saline range. TDS values 

from 28 samples collected in Sweetwater County of water produced by oil and gas extraction from the 

Nugget formation ranged from moderately saline to briny. 

TDS concentrations from 17 samples collected from the Madison aquifer in Sweetwater County ranged 

from moderately saline to briny, with a median value within the very saline range. TDS values for 11 

samples collected in Carbon County ranged from fresh to very saline, with a median value within the 

slightly/moderately saline range. TDS values from samples collected in Sweetwater County of water 

produced by oil and gas extraction from the Madison Formation ranged from moderately saline to briny. 

In general, TDS concentrations typically increase with the depth below ground surface. TDS values are 

usually higher when the aquifer is interbedded with lake or marine deposits that contain evaporate 

minerals. 

Selenium values obtained from samples of selected aquifers are included in Table 3.4-2. In comparison to 

the number of samples analyzed for TDS, selenium sampling results are sparse but they do provide some 

idea of the potential for encountering excessive selenium in produced water. EPA’s current chronic 

criterion for selenium is 5 μg/L (EPA 2011a). WDEQ/LQD’s groundwater fish/aquatic life use suitability 

limit for selenium is also 5 μg/L (WDEQ/LQD 2005). Both the EPA’s chronic criterion and WDEQWQD’s suitability limits for selenium were exceeded in Quaternary aquifer water samples. 

Confining beds typically restrict the movement of groundwater between aquifers, hence, movement of 

potential contaminants between aquifers. Although there is some downward movement of the water from 

the shallow surficial units, most of the groundwater movement, if any, is upward from the deeper 

confined aquifers to the shallower unconfined aquifers. Water in a confined aquifer is under hydraulic 

pressure and will rise above the top of the aquifer when the overlying confining bed is pierced or broken 

(Mason and Miller 2005). There is potential for groundwater quality degradation due to the piercing of 

confining layers and vertical and horizontal migration and mixing of waters of variable qualities between 

the layers. Improperly completed wells, especially poor casing or cementing, could produce such a result. 

There are no data suggesting this is currently a problem in the CD-C project area. 

3.4.3.6 Springs and Flowing Wells 

As described above, water in a confined aquifer is under hydraulic pressure and will rise above the top of 

the aquifer when the overlying confining bed is broken (spring) or pierced (well). When the hydraulic 

pressure is great enough, the water from a well completed in a confined aquifer can reach the surface, 

resulting in a flowing well. Springs and flowing wells are important local water sources for livestock, 

wildlife, and wild horses. It is unclear how many springs and flowing wells are located within the project 

area. The SEO records identify two named springs among the 1,081 groundwater rights within 1 mile of 

the project area (SEO 2011). The SEO records indicate that 118 of the 1,081 groundwater rights are 

flowing wells (SEO 2011). Of the 1,081 groundwater rights, 325 lack the information to determine if the 

groundwater permit is for a spring or flowing well. 

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According to previous studies, springs in the area intercept the ground surface in three geologic units. 

South of Interstate 80 (I-80), springs occur in the Green River Formation. North of I-80, springs occur in 

the Wasatch and Battle Springs formations (Mason and Miller 2005; Bartos et al. 2006). 

Historic water-quality data were located for 16 water samples collected from springs or flowing wells 

(WRDS 2007, USGS 2007). Water quality for these samples is variable. Conductance levels range from 

769 to 16,215 μmhos/cm. TDS levels ranged from 479 to 12,755 mg/L. Detailed information related to 

springs and flowing wells can be found in Appendix F. Based on a February 2011 search of SEO water 

rights information, none of the 16 springs evaluated for water quality are covered by valid water rights. 

3.4.3.7 The Safe Drinking Water Act as it Relates to Groundwater 

The Safe Drinking Water Act (SDWA) is the main federal law that regulates drinking water quality, 

including drinking water from groundwater sources. Under the SDWA, the EPA sets standards for 

drinking water quality and oversees the states, localities, and water suppliers who implement those 

standards. Two aspects of the SDWA that are relevant to an assessment of the groundwater quality related 

to the CD-C project are the underground injection control (UIC) program and the sole source aquifer 

(SSA) protection program. The UIC program ensures that injection wells meet appropriate performance 

criteria for protecting underground sources of drinking water (USDW). As defined in 40 CFR 144.3, an 

USDW aquifer supplies any public water system or contains a sufficient quantity of groundwater to 

supply a public water system; currently supplies drinking water for human consumption or contains fewer 

than 10,000 mg/l total dissolved solids and is not an exempted aquifer (i.e. exempt from SDWA 

regulation). The EPA defines an SSA as an aquifer that supplies at least 50 percent of the drinking water 

consumed in the area overlying the aquifer. While there are no EPA designated SSAs associated with the 

CD-C project area, there are aquifers in the area that qualify as an USDW. 

Quaternary age aquifers within the CD-C project area likely do not qualify as USDWs since there are no 

wells designated for domestic or municipal use and supply a public water system. Further, the yields from 

these aquifers are not likely sufficient to sustain a public water system. Tertiary age aquifers within the 

CD-C project area qualify as USDWs based on the presence of Wamsutter municipal wells and on the 

suitability of the groundwater quality. Wyoming State Engineer records indicate that one domestic well is 

completed in the Upper Cretaceous Lance Formation aquifer within the project area. 

There are no wells that are designated for municipal use or supply a public water system completed in 

Upper Cretaceous aquifers within the project area. Upper Cretaceous age aquifers within the CD-C 

project area qualify as USDWs based on suitability of water quality, on the presence of a sufficient 

quantity of groundwater to supply a public water system, and the one domestic well completed in the 

Lance Formation aquifer. Due to the depth of the Upper Cretaceous aquifers in the CD-C area (2,000 to 

12,000 feet depending on location [Mason and Miller 2005]) and the low population density of the area, 

these aquifers are not likely to be the target for large numbers of domestic or public water system wells. 

Lower Cretaceous and Jurassic age aquifers within the CD-C project area could qualify as USDW based 

on suitability of water quality and based on the presence of a sufficient quantity of groundwater to supply 

a public water system but, due to the depths of the aquifers in the CD-C area (2,000 to 12,000 feet 

depending on location [Mason and Miller 2005]), Lower Cretaceous and Jurassic age aquifers are not 

likely to be the target for domestic or public water system wells. Pennsylvanian age and older aquifers 

within the CD-C project area could qualify as USDW based on the presence of a sufficient quantity of 

groundwater to supply a public water system but, due to the depths of these aquifers in the CD-C area 

(4,800 to 18,000 feet depending on location [Mason and Miller 2005]) and the low population density of 

the area, they are not likely to be the target for domestic or public water system wells. 

3.4.4 Injection Wells 

As discussed above, subsurface water-disposal methods are administered by the EPA under the UIC 

program (40 CFR 144). The UIC program ensures that injection wells meet appropriate performance 

criteria for protecting USDWs. There are five classes of injection wells permitted under the UIC program 

based on similarity in the fluids injected, activities, construction, injection depth, design, and operating 

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CHAPTER 3—AFFECTED ENVIRONMENT—WATER RESOURCES 

techniques. Class II and Class V injection wells would likely be used to dispose of produced water 

resulting from the CD-C project. Class II injection well permits are issued by the WOGCC for injection 

of fluids associated with oil and natural gas production (EPA 2011b),and are issued by the WOGCC 

under a 1989 Memorandum of Agreement (MOA) between the EPA and the WOGCC. Class V injection 

wells are permitted through WDEQ-WQD and cover wells not included in Classes I-IV. Most Class V 

wells (facilities) inject non-hazardous fluids into or above USDWs and are typically shallow, onsite 

disposal systems (stormwater drainage wells, cesspools, and septic tanks) but also include more complex 

wells that are deeper and often used for commercial or industrial facilities (EPA 2011b). 

According to WOGCC information there are 18 permitted Class II injection wells within the CD-C 

project area that are capable of operation (WOGCC 2011a). The target injection formations for these 

wells are Big Red (1), Ericson (1), Fort Union (1), Fort Union/Lance (1), Fox Hills (1), Lewis (1), 

Mesaverde/Lance (1), Almond (2), Mesaverde (2), and Lance (7). According to WOGCC information 

there are no permitted Class V injection wells within the project area but there are seven Class V wells 

adjacent to the project area (WOGCC 2011a). All seven wells are the deeper injection type and target the 

Haystack Mountain (1), Deep Creek (3), and Mesaverde Coal (3) formations. 

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3.5 AIR QUALITY 

Regional air quality is influenced by a combination of factors including climate, meteorology, the 

magnitude and spatial distribution of local and regional air pollution sources, and the chemical properties 

of emitted pollutants. Within the lower atmosphere, regional and local scale air masses interact with 

regional topography to influence atmospheric dispersion and transport of pollutants. The following 

sections summarize the climatic conditions and existing air quality within the project area and 

surrounding region. 

3.5.1 Regional Climate 

The CD-C project area is located in a semiarid (dry and cold), mid-continental climate regime. The area is 

typified by dry, windy conditions with limited rainfall and long, cold winters. The nearest meteorological 

measurements were collected at Wamsutter, Wyoming (1897-2011), located near the center of the project 

area at an elevation of 6,800 feet above mean sea level; (WRCC 2012). 

The annual average total precipitation at Wamsutter is 7.1 inches, with annual totals for the period of 

record ranging from 3.8 inches (1979) to 13.6 inches (1983). Precipitation is greatest from spring to 

summer, tapering off during the fall and winter months. An average of 27.4 inches of snow falls during 

the year (annual high 78.0 inches in 2010), with the majority of the snow distributed evenly between 

November and April. 

The region has cool temperatures, with an average range (in degrees Fahrenheit [ ̊F]) between 7.1 ̊F and 

28.6 ̊F in January to between 48.9 ̊F and 84.5 ̊F in July. Extreme temperatures have ranged from -40 ̊F 

(2011) to 105 ̊F (1897). The frost-free period generally occurs from May to September. Table 3.5-1 

shows the mean monthly temperature ranges and total precipitation amounts. 

Table 3.5-1. Mean Monthly Temperature Ranges and Total Precipitation Amounts 

Month Average Temperature Range ( ̊F) Total Precipitation (inches) 

January 7.1 – 28.6 0.27 

February 10.6 – 33.1 0.29 

March 18.4 – 41.8 0.40 

April 26.5 – 54.1 0.75 

May 34.5 – 65.0 1.07 

June 42.4 – 76.5 0.81 

July 48.9 – 84.5 0.75 

August 46.8 – 82.1 0.81 

September 38.5 – 72.5 0.73 

October 28.5 – 59.0 0.58 

November 17.2 – 41.9 0.36 

December 8.5 – 29.9 0.28 

ANNUAL 41.5 (mean) 7.11 (mean) 

Source: WRCC 2012 

The CD-C project area is subject to strong and gusty winds, often accompanied by snow during the winter 

months, producing blizzard conditions and drifting snow. The closest comprehensive wind measurements 

were collected in the project area at the WDEQ meteorological monitoring station located approximately 

2 miles northwest of Wamsutter. To describe the wind flow pattern for the region a wind rose for the 

Wamsutter site, for years 2008 through 2010, is presented in Figure 3.5-1. Tables 3.5-2 and 3.5-3 

provide the wind speed and wind direction distributions in tabular format. From this information, it is 

evident that the winds originate from the west to southwest nearly 36 percent of the time and from the 

south to southeast over 37 percent of the time. 

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Figure 3.5-1. Wamsutter, WY meteorological data wind rose 

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The frequency and strength of winds greatly affect the transport and dispersion of air pollutants. The 

annual mean wind speed is 11.4 miles per hour (mph), and the relatively high average wind speed 

indicates good dispersion and mixing of any potential pollutant emissions. 

Table 3.5-2. Wind Speed Distribution, Wamsutter, Wyoming, 2008–20101 

Wind Speed (mph) Frequency (%) 

0 – 4.0 8.3 

4.0 – 7.5 25.0 

7.5 – 12.1 22.6 

12.1 – 19.0 16.9 

19.0 – 24.7 4.5 

Greater than 24.7 2.3 

1

Source: WDEQ-AQD 2012. 

Table 3.5-3. Wind Direction Frequency Distribution, Wamsutter, Wyoming, 2008–2010 

Wind Direction Frequency (%) 

N 3.3 

NNE 2.8 

NE 2.8 

ENE 1.6 

E 1.6 

ESE 6.4 

SE 14.6 

SSE 8.7 

S 7.7 

Wind Direction Frequency (%) 

SSW 6.8 

SW 5.9 

WSW 9.7 

W 13.4 

WNW 7.3 

NW 4.7 

NNW 2.8 

Source: WDEQ-AQD 2012. 

3.5.2 Overview of Regulatory Environment 

The WDEQ-AQD is the primary air quality regulatory agency responsible for estimating impacts once 

detailed industrial development plans have been made, and those development plans are subject to 

applicable air quality laws, regulations, standards, control measures, and management practices. Unlike 

the conceptual ‘reasonable, but conservative’ engineering designs used in NEPA analyses, any WDEQAQD air quality preconstruction permitting demonstrations required would be based on very site-specific, 

detailed engineering values, which would be assessed in the permit application review. Any proposed 

facility which meets the requirements set forth under Wyoming Air Quality Standards and Regulations 

(WAQSR) Chapter 6 is subject to the WDEQ-AQD permitting and compliance processes. 

Federal air quality regulations adopted and enforced by WDEQ-AQD limit incremental emission 

increases to specific levels defined by the classification of air quality in an area. The Prevention of 

Significant Deterioration (PSD) Program is designed to limit the incremental increase of specific air 

pollutant concentrations above a legally defined baseline level. Incremental increases in PSD Class I areas 

are strictly limited, while increases allowed in Class II areas are less strict. Under the PSD program, Class 

I areas are protected by Federal Land Managers (FLMs) through management of air quality related values 

((AQRVs) such as visibility, aquatic ecosystems, flora, fauna, and others. 

The 1977 Clean Air Act amendments established visibility as an AQRV for FLMs to consider. The 1990 

Clean Air Act amendments contain a goal of improving visibility within PSD Class I areas. The Regional 

Haze Rule finalized in 1999 requires states, in coordination with federal agencies and other interested 

parties, to develop and implement air quality protection plans to reduce the pollution that causes visibility 

impairment. 

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Regulations and standards which limit permissible levels of air pollutant concentrations and air emissions 

and are relevant to the CD-C project air impact analysis include: 

 NAAQS (40 CFR Part 50) , WAAQS (WAQSR Chapter 2), CAAQS (5 CCR 1001-14); 

 Prevention of Significant Deterioration (40 CFR Part 51.166); 

 New Source Performance Standards (NSPS) (40 CFR Part 60); 

 Non-Road Engine Tier Standards (40 CFR Part 89); and 

 Wyoming 2010 Oil and Gas Permitting Guidance (supplement to WAQSR Chapter 6, Section 2) 

Each of these regulations is further described in the following sections. 

3.5.2.1 Ambient Air Quality Standards 

The Clean Air Act requires the EPA to set National Ambient Air Quality Standards (NAAQS) for 

pollutants considered to endanger public health and the environment. The NAAQS prescribe limits on 

ambient levels of these pollutants in order to protect public health, including the health of sensitive 

groups. The EPA has developed NAAQS for six criteria pollutants: NO2, CO, SO2, PM10, PM2.5, ozone, 

and lead. Lead emissions from CD-C project sources are negligible and therefore the lead NAAQS is not 

addressed in this analysis. States typically adopt the NAAQS but may also develop state-specific ambient 

air quality standards for certain pollutants. The NAAQS and the state ambient air quality standards for 

Wyoming (WAAQS) and Colorado (CAAQS) are summarized in Table 3.5-4. The CAAQS are included 

in this table due to the proximity of the CD-C project area to Colorado (See Map 3.5-1). PSD Class I and 

Class II increments are also included in Table 3.5-7 and a discussion of PSD increments is provided in 

Section 3.5.2.3. The ambient air quality standards are shown in units of parts per million (ppm), parts per 

billion (ppb), and micrograms per cubic meter (μg/m3

) for purposes of providing the standards as written 

in the corresponding regulation, and for comparison with the pollutant concentration units as provided by 

the air quality models used for impact analysis (Section 4.5). 

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Map 3.5-1. Air quality monitoring stations within the CD-C study area 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

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CHAPTER 3—AFFECTED ENVIRONMENT—AIR QUALITY 

Table 3.5-4. Ambient air quality standards and PSD increments (μg m3) 

Pollutant Averaging 

Time 

NAAQS CAAQS WAAQS 

(ppm) (ppb) (μg/m3 

) (ppm) (ppb) (μg/m3 ) (ppm) (ppb) (μg/m3 ) 

CO 1-hour1 35 35,000 40,000 35 35,000 40,000 35 35,000 40 (mg/m3) 

8-hour1 9 9,000 10,000 9 9,000 10,000 9 9,000 10 (mg/m3) 

NO2 

1-hour2 0.1 100 188 0.1 100 188 -- -- --

Annual3 0.053 53 100 0.053 53 100 0.053 53 100 

Ozone 8-hour4 0.075 75 147 0.075 75 147 0.08 80 157 

PM10 

24-hour1 NA NA 150 NA NA 150 NA NA 150 

Annual3 NA NA --5 NA NA -- NA NA 50 

PM2.5 

24-hour6 NA NA 35 NA NA 35 NA NA 35 

Annual3 NA NA 15 NA NA 15 NA NA 15 

SO2 

1-hour7 0.075 75 196 0.075 75 196 -- -- --

3-hour1 0.5 500 1,300 0.267 267 700 0.5 500 1,300 

24-hour1 --5 -- -- -- -- -- 0.10 100 260 

Annual3 --5 -- -- -- -- -- 0.02 23 60 

Note: Bold indicates the standard as written the corresponding regulation. Other values are conversions. 

1 Not to be exceeded more than once per year. 

2 An area is in compliance with the standard if the 98th percentile of daily maximum 1-hour NO2 concentrations in a year, averaged 

over 3 years, is less than or equal to the level of the standard. 

3 Annual arithmetic mean. 

4 An area is in compliance with the standard if the fourth-highest daily maximum 8-hour ozone concentrations in a year, averaged 

over 3 years, is less than or equal to the level of the standard. 

5 The NAAQS for this averaging time for this pollutant has been revoked by EPA. 

6 An area is in compliance with the standard if the highest 24-hour PM2.5 concentrations in a year, averaged over 3 years, is less 

than or equal to the level of the standard. 7 An area is in compliance with the standard if the 99th percentile of daily maximum 1-hour SO2 concentrations in a year, averaged 

over 3 years, is less than or equal to the level of the standard. 

An area that is shown to exceed the NAAQS for a given pollutant may be designated as a non-attainment 

area for that pollutant. In March 2009, the Governor of Wyoming recommended to the EPA that Sublette 

County and parts of northeastern Lincoln and northwestern Sweetwater Counties be designated nonattainment for ozone due to exceedances of the 2008 75 parts per billion ozone NAAQS. The CD-C 

project area is located in eastern Sweetwater and western Carbon counties, outside of the proposed nonattainment area. In April 2012, Sublette County and parts of Lincoln and Sweetwater were designated by 

the EPA as nonattainment areas under the 2008 ozone standard <http://www.epa.gov/groundlevelozone/­

designations/2008standards/final/region8f.htm>. 

3.5.2.2 Hazardous Air Pollutants 

Toxic air pollutants, also known as hazardous air pollutants (HAPs), are those pollutants that are known 

or suspected to cause cancer or other serious health effects, such as reproductive effects or birth defects, 

or adverse environmental effects. No ambient air quality standards exist for HAPs; instead, emissions of 

these pollutants are controlled by a variety of regulations that target the specific source class and 

industrial sectors for stationary, mobile, and product use/formulations. Sources of HAPs from CD-C 

operations include well-site production emissions (benzene, toluene, ethyl benzene, xylene, n-hexane, and 

formaldehyde), and compressor station and gas plant combustion emissions (formaldehyde). 

For the CD-C analysis, short-term (1-hour) HAP concentrations are compared to acute Reference 

Exposure Levels (RELs) (EPA, 2011) shown in Table 3.5-5. RELs are defined as concentrations at or 

below which no adverse health effects are expected. No RELs are available for ethyl benzene and nhexane; instead, the available “Immediately Dangerous to Life or Health” values divided by 10 

(IDLH/10) are used. These IDLH values were determined by the National Institute for Occupational 

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Safety and Health and were obtained from EPA's Air Toxics Database (EPA, 2011). These values are 

approximately comparable to mild effects levels for 1-hour exposures. 

Long-term exposure to HAPs are compared to Reference Concentrations for Chronic Inhalation (RfCs). 

An RfC is defined by the EPA as the daily inhalation concentration at which no long-term adverse health 

effects are expected. RfCs exist for both non-carcinogenic and carcinogenic effects on human health 

(EPA, 2010). Annual modeled HAP concentrations for all HAPs emitted were compared directly to the 

non-carcinogenic RfCs shown in Table 3.5-6.. 

Long-term exposures to emissions of suspected carcinogens (benzene, ethyl benzene and formaldehyde) 

are also evaluated based on estimates of the increased latent cancer risk over a 70-year lifetime. 

Table 3.5-5. Acute RELs (1-hour exposure) 

HAP REL (μg/m3) 

Benzene 1,3001 

Toluene 37,0001 

Ethyl Benzene 350,0002 

Xylene 22,0001 

n-Hexane 390,0002 

Formaldehyde 551 

1 EPA Air Toxics Database, Table 2 (EPA, 2011). 

2 No REL available for these HAPs. Values shown are from Immediately 

Dangerous to Life or Health (IDLH/10), EPA Air Toxics Database, 

Table 2 (EPA, 2011). 

Table 3.5-6. Non-Carcinogenic HAP RfCs (annual average)1 

HAP Non-CarcinogenicRfC1 (μg/m3) 

Benzene 30 

Toluene 5000 

Ethyl Benzene 1,000 

Xylenes 100 

n-Hexane 700 

Formaldehyde 9.8 

1 EPA Air Toxics Database, Table 1 (EPA, 2010). 

3.5.2.3 Prevention of Significant Deterioration 

The PSD Program is designed to limit the incremental increase of specific air pollutant concentrations 

above a legally defined baseline level. All areas of the country are assigned a classification which 

describes the degree of degradation to the existing air quality that is allowed to occur within the area 

under the PSD permitting rules. PSD Class I areas are areas of special national or regional natural, scenic, 

recreational, or historic value, and very little degradation in air quality is allowed by strictly limiting 

industrial growth. PSD Class II areas allow for reasonable industrial/economic expansion. Certain 

national parks and wilderness areas are designated as PSD Class I, and air quality in these areas is 

protected by allowing only slight incremental increases in pollutant concentrations. Five PSD Class I 

areas are located within the CD-C study area as shown on Map 3.5-1: the Bridger, Fitzpatrick, Mount 

Zirkel, Savage Run, and Rawah Wilderness Areas. In a PSD increment analysis, impacts from proposed 

emissions sources are compared with the allowable limits on increases in pollutant concentrations, which 

are called Class I PSD increments; these increments are shown in Table 3.5-7. Dinosaur National 

Monument is a federal PSD Class II area given Class I protection for SO2 by the Colorado Department of 

Public Health and Environment (CDPHE). The remainder of the impact study area is classified as PSD 

Class II, where less stringent limits on increases in pollutant concentrations apply. The Popo Agie 

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Wilderness Area and the Wind River Roadless Area are considered sensitive areas and are subject to the 

PSD Class II Increments shown in Table 3.5-7. 

Table 3.5-7. PSD increments (μg/m3) 

Pollutant Averaging Time PSD Class I 

Increment 

PSD Class II 

Increment 

NO2 1-hour None None 

Annual 2.5 25 

PM10 24-hour 8 30 

Annual 4 17 

PM2.5 24-hour 2 9 

Annual 1 4 

SO2 1-hour None None 

3-hour 25 512 

24-hour 5 91 

Annual 2 20 

Note: The PSD demonstrations serve information purposes only and do not constitute a 

regulatory PSD increment consumption analysis. 

Comparisons of CD-C project impacts to the PSD Class I and II increments are for informational 

purposes only and are intended to evaluate a threshold of concern. They do not represent a regulatory 

PSD Increment Consumption Analysis, which would be completed as necessary during the New Source 

Review permitting process by the State of Wyoming. 

In addition to the PSD increments, Class I areas are protected by FLMs through management of AQRVs 

such as visibility, aquatic ecosystems, flora, and fauna. Evaluations of impacts to AQRVs would also be 

performed during the New Source Review permitting process under the direction of the WDEQ-AQD in 

consultation with the FLMs. 

AQRVs that were identified as a concern for the CD-C project included visibility, atmospheric deposition, 

and potential sensitive lake acidification. A discussion of the applicable background data and analysis 

thresholds is provided below. 

Visibility 

Change in atmospheric light extinction relative to background conditions is used to measure regional 

haze. Analysis thresholds for atmospheric light extinction are set forth in The Federal Land Managers’ 

Air Quality Related Values Work Group (FLAG) Report (FLAG 2010), with the results reported in 

percent change in light extinction and change in deciviews (dv). A 5-percent change in light extinction 

(approximately equal to 0.5 dv) is the threshold recommended in FLAG (2010) and is considered to 

contribute to regional haze visibility impairment. A 10-percent change in light extinction (approximately 

equal to 1.0 dv) is considered to represent a noticeable change in visibility when compared to background 

conditions. 

Estimated visibility degradation at the Class I areas and sensitive Class II areas of concern are presented 

in terms of the number of days that exceed a threshold percent change in extinction, or dv relative to 

background conditions. Although procedures and thresholds have not been established for sensitive Class 

II areas, BLM is including these areas in its visibility analysis. 

Atmospheric Deposition and Lake Chemistry 

The effects of atmospheric deposition of nitrogen and sulfur compounds on terrestrial and aquatic 

ecosystems are well documented and have shown to cause leaching of nutrients from soils, acidification 

of surface waters, injury to high-elevation vegetation, and changes in nutrient cycling and species 

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composition. FLAG (2010) recommends that applicable sources assess impacts of nitrogen and sulfur 

deposition in Class I areas. 

This guidance recognizes the importance of establishing critical deposition loading values (“critical 

loads”) for each specific Class I area as these critical loads are completely dependent on local 

atmospheric, aquatic, and terrestrial conditions and chemistry. Critical load thresholds are essentially a 

level of atmospheric pollutant deposition below which negative ecosystem effects are not likely to occur. 

FLAG 2010 does not include any critical load levels for specific Class I areas and refers to site-specific 

critical load information on FLM websites for each area of concern. This guidance does, however, 

recommend the use of deposition analysis thresholds (DATs) developed by the National Park Service 

(NPS) and the Fish and Wildlife Service (USFWS). The DATs represent screening level values for 

nitrogen and sulfur deposition from project alone emission sources below which estimated impacts are 

considered negligible. The DAT established for both nitrogen and sulfur in western Class I areas is 0.005 

kilograms per hectare per year (kg/ha/yr). 

In addition to the screening level analysis, project-specific and cumulative modeled results are compared 

to critical load thresholds established for the Rocky Mountain region to assess total deposition impacts. 

The BLM has compiled currently available research data on critical load values for Class I areas in the 

vicinity of the CD-C project area. Critical load thresholds published by Fox et al. (Fox 1989) established 

pollutant loadings for total nitrogen of 3–5 kg/ha/yr) and for total sulfur of 5 kg/ha/yr for Bob Marshall 

Wilderness Area in Montana and Bridger Wilderness Area in Wyoming. However, the NPS has recently 

stated that these pollutant loadings are not protective of sensitive resources and in its “Technical 

Guidance on Assessing Impacts to Air Quality in NEPA and Planning Documents” (January 2011) 

suggested that critical load values above 3 kg/ha/yr may result in moderate impacts. Research conducted 

by Jill Baron (Baron 2006) using hindcasting of diatom communities suggests 1.5 kg/ha/yr as a critical 

loading value for wet nitrogen deposition for high-elevation lakes in Rocky Mountain National Park, 

Colorado. Recent research conducted by Saros et. al. (2010) using fossil diatom assemblages suggest that 

a critical load value of 1.4 kg/ha/yr for wet nitrogen is applicable to the eastern Sierra Nevada and Greater 

Yellowstone ecosystems. For the CD-C project, both project-specific and cumulative nitrogen and sulfur 

deposition impacts are compared to the following critical load values: 1.5 kg/ha/yr as a surrogate for total 

nitrogen deposition and 3 kg/ha/yr for total sulfur deposition for the Class I and sensitive Class II areas 

evaluated. 

Analyses to assess the change in water chemistry associated with atmospheric deposition are performed 

following the procedures developed by the USFS Rocky Mountain Region (USFS 2000). The analysis 

assesses the change in the acid neutralizing capacity (ANC) of the 12 sensitive lakes (Table 3.5-6) within 

the CD-C study area (Map 3.5-1). Predicted changes in ANC are compared with the applicable threshold 

for each identified lake: 10-percent change in ANC for lakes with background ANC values greater than 

25 microequivalents per liter [μeq/L], and less than a 1-μeq/L change in ANC for lakes with background 

ANC values equal to or less than 25 μeq/L. 

3.5.2.4 New Source Performance Standards 

Under Section 111 of the Clean Air Act, the EPA has promulgated technology-based emissions standards 

which apply to specific categories of stationary sources. These standards are referred to as New Source 

Performance Standards (NSPS; 40 CFR Part 60). The NSPS potentially applicable to the CD-C project 

include the following subparts of 40 CFR Part 60: 

 Subpart A – General Provisions; 

 Subpart Kb – Standards of Performance for Volatile Organic Storage Vessels; 

 Subpart JJJJ – Standards of Performance for Stationary Spark-Ignition Internal Combustion 

Engines; and 

 Subpart KKKK – Standards of Performance for Stationary Combustion Turbines. 

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Subpart A – General Provisions 

Provisions of Subpart A apply to the owner or operator of any stationary source which contains an 

affected facility, the construction or modification of which is commenced after the date of publication in 

this part of any standard (or, if earlier, the date of publication of any proposed standard) applicable to that 

facility. Provisions of Subpart A could apply to proposed CD-C sources that are affected by NSPS. 

Subpart Kb – Volatile Organic Liquid Storage Vessels 

Subpart Kb applies to storage vessels with a capacity greater than or equal to 75 cubic meters (m3) that 

are used to store volatile organic liquids for which construction, reconstruction, or modification is 

commenced after July 23, 1984. This subpart potentially would be applicable to storage tanks for natural 

gas liquids. 

Subpart JJJJ – Spark Ignition Internal Combustion Engines 

Subpart KKKK establishes emission standards and compliance schedules for the control of emissions 

from stationary combustion turbines that commenced construction, modification or reconstruction after 

February 18, 2005. Stationary combustion turbines with a heat input at peak load equal to or greater than 

10.7 gigajoules (10 MMBtu) per hour, based on the higher heating value of the fuel proposed as part of 

the CD-C project, would be subject to this NSPS. 

Subpart KKKK – Stationary Combustion Turbines 

Subpart KKKK establishes emission standards and compliance schedules for the control of emissions 

from stationary combustion turbines that commenced construction, modification or reconstruction after 

February 18, 2005. Stationary combustion turbines with a heat input at peak load equal to or greater than 

10.7 gigajoules (10 MMBtu) per hour, based on the higher heating value of the fuel proposed as part of 

the CD-C project would be subject to this NSPS. 

3.5.2.5 Non-Road Engine Tier Standards 

The EPA sets emissions standards for non-road diesel engines for hydrocarbons, NOX, CO, and PM. The 

emissions standards are implemented in tiers by year, with different standards and start years for various 

engine power ratings. The new standards do not apply to existing non-road equipment. Only equipment 

built after the start date for an engine category (1999-2006, depending on the category) is affected by the 

rule. Over the life of the CD-C project, the fleet of non-road equipment will turn over and higher-emitting 

engines will be replaced with lower-emitting engines. This fleet turnover is accounted for in the CD-C 

project emissions inventory. 

3.5.2.6 Wyoming 2010 Oil and Gas Permitting Guidance (Wyoming BACT) 

The CD-C project area lies entirely within eastern Sweetwater County and western Carbon County in 

Wyoming; this area is part of the State of Wyoming’s Concentrated Development Area (CDA; Map 3.5-

3), and is therefore subject to CDA restrictions on emissions set forth in the WDEQ-AQD’s March 2010 

“Oil and Gas Production Facilities Chapter 6, Section 2 Permitting Guidance” (WDEQ-AQD, 2010). The 

Guidance states, “....all new or modified sources or facilities which may generate regulated air emissions 

shall be permitted prior to start-up or modification and Best Available Control Technology (BACT) shall 

be applied to reduce or eliminate emissions”. The Guidance establishes presumptive BACT requirements 

for emissions from the following source categories for new facilities: 

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	 Tank Flashing8

 (see Glossary). Pad facilities: 98-percent control upon startup; single-well facilities: 

98-percent control of all new/modified tank emissions ≥ 8 tpy (tons per year) VOC within 60 days 

of startup/modification. 

	 Dehydration Units. Upon first date of production (FDOP), glycol flash separators and still vent 

condensers must be installed/operating on all dehydrators; 98-percent control must be 

installed/operational on dehydrators within 30 days of FDOP if total potential uncontrolled 

dehydrator VOC emissions are ≥8 tpy; combustion units used to achieve 98-percent control may be 

removed upon approval after 1 year if total potential VOC emissions from dehydrators are <8 tpy. 

	 Pneumatic Pumps. Pad facilities: VOC and HAP emissions associated with the discharge streams of 

all natural gas-operated pneumatic pumps controlled by at least 98 percent or the pump discharge 

streams routed into a closed-loop system such as sales line, collection line, fuel supply; single-well 

facilities with combustion units installed for the control of flash or dehydration unit emissions: VOC 

and HAP emissions associated with the discharge streams from natural gas-operated pneumatic 

pumps controlled by at least 98 percent by routing the pump discharge streams into the combustion 

unit or the discharge streams routed into a closed loop system. 

	 Pneumatic Controllers. Install low- or no-bleed controllers at all new facilities. 

	 Well Completions. Green completions are required in the Jonah, Pinedale and Anticline 

development fields (JPAD) area and concentrated development areas (Map 3.5-2). 

	 Produced Water Tanks. Pad facilities-upon FDOP, 98-percent control of all produced water tank 

emissions. No water produced into open-top tanks; single-well facilities within 60 days of FDOP, 

98-percent control of all produced water tank emissions at sites where flashing emissions must be 

controlled. No water produced into open-top tanks. 

	 Blow-down/Venting. Best Management Practices and information-gathering requirements 

incorporated into permits for new and modified facilities. 

	 Other sources. For uncontrolled sources emitting ≥8 tpy VOC or ≥5 tpy total HAPs that do not have 

presumptive BACT requirements, a BACT analysis must be filed with the permit application for the 

associated facility. 

8 Flashing losses occur when a liquid with entrained gases goes from a higher pressure to a lower pressure. As the pressure on the 

liquid drops, some of the compounds dissolved in the liquid are released, or “flashed” as gas. 

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Map 3.5-2. The concentrated development area (from WDEQ-AQD, 2010) 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

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3.5.2.7 Greenhouse Gases (GHGs) 

Greenhouse gases (GHGs) present in the earth’s atmosphere trap outgoing longwave radiation and warm 

the earth’s atmosphere. Higher concentrations of GHGs in the atmosphere result in more heat being 

absorbed and cause higher global temperatures. Some GHGs, such as water vapor, occur naturally in the 

atmosphere, and some such as carbon dioxide (CO2) and methane (CH4) occur naturally and are also 

emitted by human activities. The global atmospheric concentration of CO2 has increased by about 36 

percent over the last 250 years, and far exceeds pre-industrial values determined from ice cores spanning 

many thousands of years (IPCC, 2007). The anthropogenic GHGs of primary concern are: CO2, CH4, NO2 

and fluorinated gases. Ice core records extending back over thousands of years indicate that worldwide 

emissions of these anthropogenic GHGs have increased dramatically during the industrial era with an 

increase of 70 percent between 1970 and 2004 alone (IPCC, 2007). 

The Intergovernmental Panel on Climate Change (IPCC) is the leading international body for the 

assessment of climate change. It was established by the United Nations Environment Programme and the 

World Meteorological Organization in 1988 to provide a clear scientific view on the current state of 

knowledge about climate change and its potential environmental and socioeconomic impacts. The main 

activity of the IPCC is to provide at regular intervals Assessment Reports of the state of knowledge on 

climate change. The latest report is “Climate Change 2007,” the IPCC Fourth Assessment Report (AR4). 

(IPCC 2007). In AR4, the IPCC concluded that warming of the climate system is unequivocal and most of 

the observed increase in global average temperatures since the mid 20th century is very likely due to the 

observed increase in anthropogenic greenhouse gas concentrations. The IPCC further concluded that, 

“continued greenhouse gas emissions at or above current rates would cause further warming and induce 

many changes in the global climate system during the 21st century that would very likely be larger than 

those observed during the 20th century.” 

The impacts of climate change are expected to vary by region, and there is significant uncertainty 

regarding the effects of climate change on any particular region. In particular, it is unknown how climate 

change will affect the CD-C project area or its surrounding environment. However, AR4 identified 

specific risks for North America as a whole, and these are shown below: 

	 Warming in western mountains is projected to cause decreased snowpack, more winter flooding and 

reduced summer flows, exacerbating competition for over-allocated water resources. 

	 In the early decades of the century, moderate climate change is projected to increase aggregate 

yields of rain-fed agriculture by 5 to 20 percent, but with important variability among regions. 

Major challenges are projected for crops that are near the warm end of their suitable range or which 

depend on highly utilized water resources. 

	 Cities that currently experience heat waves are expected to be further challenged by an increased 

number, intensity, and duration of heat waves during the course of the century, with potential for 

adverse health impacts. 

	 Coastal communities and habitats will be increasingly stressed by climate change impacts 

interacting with development and pollution. 

The GHGs projected to be emitted by the CD-C Project Alternatives are CO2, CH4 and NO2. The 

atmospheric lifetimes for CO2, CH4 and NO2 are on the order of years (IPCC, 2007). Emissions of GHGs 

from any particular source become well-mixed throughout the global atmosphere. GHG emissions from 

all sources contribute to the global atmospheric burden of GHGs, and it is not possible to attribute a 

particular climate impact in any given region to GHG emissions from a particular source. It is possible to 

state only that GHG emissions produced by the Proposed Action and action alternatives would add to the 

global burden of GHGs and may therefore contribute to climate change impacts to the Affected 

Environment produced by world-wide emissions; these impacts may include those shown above. 

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In 2007, the U.S. Supreme Court ruled in Massachusetts v. EPA that EPA has the authority to regulate 

greenhouse gases such as CH4 and CO2 as air pollutants under the Clean Air Act. The ruling did not, 

however, require the EPA to create any emission control standards or ambient air quality standards for 

GHGs. At present there are no ambient air quality standards for GHGs, and there are no emissions limits 

on GHGs that would apply to the sources developed under the Proposed Action and the action 

alternatives. There are, however, applicable reporting requirements under the EPA’s Greenhouse Gas 

Reporting Program. These GHG emission reporting requirements, finalized in 2010 under 40 CFR Part 

98, will require the Operators to develop and report annual methane and CO2 emissions from equipment 

leaks and venting, and emissions of CO2, CH4, and N2O from flaring, onshore production stationary and 

portable combustion emissions, and combustion emissions from stationary equipment. At present, there 

are no rules related to GHG emissions or impacts that would affect development of the Proposed Action 

or the action alternatives besides these GHG reporting requirements. 

3.5.3 Air Pollutant Concentrations 

The U.S. EPA and the states set limits on permissible concentrations of air pollutants. The National 

Ambient Air Quality Standards (NAAQS), Wyoming Ambient Air Quality Standards (WAAQS), and 

Colorado Ambient Air Quality Standards (CAAQS) are health-based criteria for the maximum acceptable 

concentrations of air pollutants at all locations to which the public has access. 

Monitoring of air pollutant concentrations has been conducted within both the CD-C project area and the 

study area, shown in Map 3.5-1. Map 3.5-1 presents the locations of ambient air monitoring sites within 

the study area. These monitoring sites are part of several monitoring networks overseen by state and 

federal agencies, including: WDEQ (State of Wyoming), Clean Air Status and Trends Network 

(CASTNET), Interagency Monitoring of Protected Visual Environments (IMPROVE), and National Acid 

Deposition Program (NADP) National Trends Network (NTN). 

The study area shown in Map 3.5-1 encompasses five Prevention of Significant Deterioration (PSD) 

Class I areas and three sensitive Class II areas. The five Class I areas located within the CD-C study area 

are the Bridger, Fitzpatrick, Mount Zirkel, Savage Run, and Rawah Wilderness Areas, and the three 

sensitive Class II areas are the Popo Agie Wilderness Area, Dinosaur National Monument, and Wind 

River Roadless Area. 

Air pollutants monitored at these sites include carbon monoxide (CO), nitrogen dioxide (NO2), ozone, 

particulate matter less than 10 microns in effective diameter (PM10), particulate matter less than 2.5 

microns in effective diameter (PM2.5), and sulfur dioxide (SO2). Background concentrations of these 

pollutants define ambient air concentrations in the region and establish existing compliance with ambient 

air quality standards. The most representative monitored regional background concentrations available for 

criteria pollutants as identified by WDEQ-AQD (WDEQ-AQD, 2011) are shown in Table 3.5-8. 

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Table 3.5-8. Background ambient air quality concentrations (μg/m3) 

Pollutant Averaging Period Measured Background 

Concentration 

CO1 1-hour 

8-hour 

1,026 

798 

NO2 

2 1-hour 

Annual 

75 

9.1 

O3 

3 8-hour 126.1 

PM10 4 24-hour 

Annual 

56 

13.5 

PM2.5 5 24-hour 

Annual 

9.2 

4.2 

SO2 

6 1-hour 

3-hour 

24-hour 

Annual 

19.7 

11.5 

4.2 

3.8 

1 Data collected during 2008 at Murphy Ridge, Wyoming; concentrations are maximum 

values. 

2 Data collected at Wamsutter, Wyoming: 1-hour concentration is the three year average 

(2008-2010) of daily maximum 98th percentile 1-hour concentrations, annual value is for 

2010. 

3 Data collected at Wamsutter, Wyoming: 8-hour concentration is the three year average 

(2008-2010) of the fourth-highest daily maximum 8-hour concentrations. 

4 Data collected at Wamsutter, Wyoming during 2010, 24-hour value is maximum 

concentration. 

5 Data collected at Cheyenne, Wyoming: 24-hour value is the three year average (2008-

2010) of daily maximum 98th percentile 24-hour concentrations, annual value is three year 

average of annual means (2008-2010). 

6 Data collected at Wamsutter, Wyoming: 1-hour value is the three year average (2007-

2009) of daily maximum 98th percentile 1-hour concentrations, 3-hour, 24-hour and annual 

concentrations were collected during 2009, 3-hour and 24-hour data are maximum values. 

3.5.4 Air Quality Related Values 

An AQRV is a resource “that may be adversely affected by a change in air quality. The resource may 

include visibility or a specific scenic, cultural, physical, biological, ecological, or recreational resource 

(FLAG 2010). The (AQRVs) visibility, atmospheric deposition, and the change in water chemistry 

associated with atmospheric deposition at acid-sensitive lakes have been identified as a concern at several 

Class I and sensitive Class II areas within the study area. 

Visibility conditions can be measured as standard visual range (SVR), the farthest distance at which an 

observer can just see a black object viewed against the horizon sky; the larger the SVR, the cleaner the 

air. Visibility for the region is considered to be very good. Continuous visibility-related optical 

background data have been collected in the PSD Class I Mount Zirkel and Bridger Wilderness Areas, as 

part of the Interagency Monitoring of Protected Visual Environments (IMPROVE) program. The average 

SVR at the both the Mount Zirkel and Bridger Wilderness Areas is over 200 kilometers (Visibility 

Information Exchange Web System [VIEWS] 2012). 

Atmospheric deposition refers to the processes by which air pollutants are removed from the atmosphere 

and deposited on terrestrial and aquatic ecosystems, and it is reported as the mass of material deposited on 

an area per year (kg/ha-yr). Air pollutants are deposited by wet deposition (precipitation) and dry 

deposition (gravitational settling of pollutants). The chemical components of wet deposition include 

sulfate (SO4), nitrate (NO3), and ammonium (NH4); the chemical components of dry deposition include 

SO4, SO2, NO3, NH4, and nitric acid (HNO3). 

The National Acid Deposition Program (NADP) and the National Trends Network (NTN) station 

monitors wet atmospheric deposition and the Clean Air Status and Trends Network (CASTNET) station 

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CHAPTER 3—AFFECTED ENVIRONMENT—AIR QUALITY 

monitors dry atmospheric deposition at sites near Centennial/Brooklyn Lake, and Pinedale which are 

approximately 65 miles east-southeast, and 95 miles northwest, respectively, of the project area. The total 

annual deposition (wet and dry) reported as total nitrogen and total sulfur deposition for year 2009 at 

shown in Table 3.5-9. 

Table 3.5-9. Background nitrogen and sulfur deposition values (kg/ha-yr) 

Site Location Nitrogen Deposition Sulfur Deposition Year of Monitoring Wet Dry Total Wet Dry Total 

Centennial 2.60 0.53 3.13 1.51 0.17 1.68 2009 

Pinedale 1.00 0.34 1.34 0.47 0.14 0.61 2009 

EPA (2012b). 

Table 3.5-10 presents a list of 12 lakes within the study area that have been identified as acid sensitive. 

Analyses for potential changes to lake acidity from atmospheric deposition are based on the ANC for the 

lake. The most recent lake chemistry background ANC data are also shown in Table 3.5-9. The ANC 

values shown are the 10th percentile lowest ANC values which were calculated for each lake following 

procedures provided from the USFS. The years of monitoring data that were currently available, and the 

number of samples used in the calculation of the 10th percentile lowest ANC values, are provided. 

Of the 12 lakes listed in Table 3.5-10, two lakes (Lazy Boy and Upper Frozen) are considered by the 

USFS as extremely sensitive to atmospheric deposition since the background ANC values are less than 25 

microequivalents per liter (μeq/l). 

Table 3.5-10. Background ANC values for acid-sensitive lakes 

Wilderness 

Area Lake Latitude (Deg-Min-Sec) 

Longitude 

(Deg-MinSec) 

10th Percentile 

Lowest ANC 

Value 

(μeq/l) 

Number 

of 

Samples 

Monitoring 

Period 

Bridger Black Joe 42o44'22" 109o10'16" 69.7 78 1984-2009 

Bridger Deep 42o43'10" 109o10'15" 60.4 75 1984-2009 

Bridger Hobbs 43o02'08" 109o40'20" 70.1 85 1984-2009 

Bridger Lazy Boy 43o19'57" 109o43'47" 12.4 5 1997-2009 

Bridger Upper Frozen 42o41'13" 109o09'39" 7.4 12 1997-2009 

Fitzpatrick Ross 43o22'41" 109o39'30" 54.1 60 1988-2009 

Mount Zirkel Lake Elbert 40o38'3" 106o42'25" 53.6 67 1985-2007 

Mount Zirkel Seven Lakes 40o53'45" 106o40'55" 40.5 24 1985-2007 

Mount Zirkel Summit Lake 40o32'43" 106o40'55" 48.0 108 1985-2007 

Popo Agie Lower 

Saddlebag 

42o37'24" 108o59'38" 55.6 59 1989-2009 

Rawah Island 40o37'38'' 105o56'28'' 71.4 21 1996-2009 

Rawah Rawah Lake #4 40o40'16'' 105o57'28'' 41.6 26 1996-2009 

Source: USFS (2010). 

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CHAPTER 3—AFFECTED ENVIRONMENT—VEGETATION
 

 BIOLOGICAL ENVIRONMENT 

3.6 VEGETATION AND BIOLOGICAL SOIL CRUSTS 

3.6.1 Introduction 

The CD-C project area is located within the Omernik Level III “Wyoming Basin” Ecoregion 18 (Omernik 

1987). This ecoregion is described as a broad intermontane basin dominated by arid grasslands and 

shrublands and interrupted by high hills and low mountains. Ecoregion 18 is further divided into seven 

smaller Level IV Ecoregions (18a through 18g) to provide a better description of local diversity within the 

Wyoming Basin (Chapman et al. 2004). Two of these Level IV Ecoregions are present within the project 

area: 18a (Rolling Sagebrush Steppe) and 18e (Salt Desert Shrub Basins). The approximate boundaries of 

these two ecoregions within the project area are shown in Map 3.6-1. 

Ecoregion 18a is described as a semiarid, vast region of rolling plains, alluvial and outwash fans, hills, 

cuestas (a ridge with a gentle slope on one side and a cliff on the other), mesas, and terraces. Average 

annual precipitation in this ecoregion ranges from 10–12 inches depending upon elevation and proximity 

to mountains. The dominant vegetation in this ecoregion is sagebrush (Artemisia spp.), often associated 

with various wheatgrasses (Agropyron spp.) or fescue (Festuca spp.). Elevation, aridity, slope, aspect, 

snow accumulation, prevailing winds, and other factors all affect the species composition, morphology, 

and density of sagebrush communities in the ecoregion. Ecotones between sagebrush steppe and adjacent 

mountain ecoregions may appear at elevations as high as 9,800 feet (Omernik 1987). The ecoregion is 

also interspersed with desert shrublands, dunes, and barren area in more arid regions (e.g., Red Desert); 

and with mixed-grass prairie at the eastern limit of the ecoregion (Knight 1994). Streams originating in 

the center of the basin are usually incised with a low gradient with fine gravel substrates derived from 

shales. Small streams are ephemeral or weakly intermittent with sand or platy shale substrates (EPA 2003, 

2004). 

The Salt Desert Shrub (18e) ecoregion includes disjunct playas and isolated sand dunes. The plains, 

terraces, and rolling alluvial fans of Ecoregion 18e have soils that tend to be more alkaline and less 

permeable than soils in the Rolling Sagebrush Steppe (18a). Vegetation is a sparse cover of xeric-adapted 

species such as shadscale (Atriplex confertifolia), greasewood (Sarcobatus vermiculatus), and Gardner’s 

saltbush (Atriplex gardneri). Areas with stabilized sand dunes are dominated by alkali cordgrass 

(Spartina gracilis), Indian ricegrass (Achnatherum hymenoides), blow-out grass (Redfieldia flexuosa), 

alkali wildrye (Leymus simplex), and needle-and-thread (Hesperostipa comata). This arid region is 

sensitive to grazing pressure, which may promote the spread of invasive weeds such as Russian thistle 

(Salsola kali), cheatgrass (Bromus tectorum), and halogeton (Halogeton glomeratus). Land use is 

primarily rangeland and wildlife habitat (Omernik 1987). Streams are incised and flow into playa areas 

which are usually seasonal and have high levels of soluble salts (e.g., Chain Lakes area). Substrate is 

commonly fine-textured material or platy shale gravels (EPA 2003, 2004). 

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Map 3.6-1. General location of Level IV Ecoregions within the CD-C project area 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

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CHAPTER 3—AFFECTED ENVIRONMENT—VEGETATION
 

3.6.2 Primary Cover Types 

Native plants in the project area are predominantly drought-tolerant low shrub, grass, and flowering forb 

species that are generally distributed according to the biological, chemical, and physical properties of the 

parent soils of the area, as well as elevation, slope, aspect, and water availability.9 

Fourteen primary cover types were identified and classified in the project area using the digitized data that 

were field-verified throughout the 2007 growing season. Ten of the 14 cover types are vegetation cover 

types and the remaining four are non-vegetated (bare ground, water, rock or talus slopes, and playas). 

Table 3.6-1 shows the GIS-derived acreage of each vegetation and non-vegetated cover type. The 

distribution of the various cover types on the project area is shown on Map 3.6-2. 

Table 3.6-1. Primary cover types within the project area 

Primary Cover Type Acres Percent of Total 

Project Surface Area 

Wyoming Big Sagebrush 417,572.7 39.00 

Greasewood flats and fans 246,272.7 23.00 

Saltbush flats and fans 172,698.7 16.10 

Mixed desert shrub 142,062.6 13.30 

Mountain Big Sagebrush 54,605.9 5.10 

Basin Big Sagebrush 7,157.1 0.70 

Basin grassland 5,122.2 0.50 

Bare ground 4,117.5 0.40 

Water 2,128.5 0.20 

Rock or talus slope 1,033.9 0.10 

Riparian/wet meadow 1,003.7 0.10 

Juniper woodland 536.0 0.05 

Vegetated sand dunes 275.5 0.03 

Playa 124.3 0.01 

Extended drought conditions throughout southwestern and south-central Wyoming have adversely 

impacted many native shrub communities and several drought-related die-backs and die-offs are evident 

throughout the project area. The greatest mortality appears to occur in Artemisia species and subspecies 

that are more adapted to mesic sites, e.g., basin big sagebrush (Artemisia tridentata ssp. tridentata) (ATT) 

and mountain big sagebrush (A.t. spp. vaseyana var. vaseyana and var. pauciflora). The majority of shrub 

mortality appears to be localized within and along the many draws (e.g., Barrel Springs Draw, Red Wash 

Draw) and ephemeral drainages within the project area that, in a normal precipitation year, retain enough 

moisture through the summer months to support the water requirements of these taxa. The more xericadapted Wyoming big sagebrush (A.t. wyomingensis) (ATW) subspecies and Gardner’s saltbush (Atriplex 

gardneri) communities have been least affected. However, many ATW plants exhibit individual stem 

death which is common for this subspecies under severe moisture stress (Fisser 1987). With the exception 

of the 2007 growing season, seed production of ATW and Gardner’s saltbush has been minimal over the 

past six to seven years as a result of drought stress. Plant mortality is also evident in several greasewood 

(Sarcobatus vermiculatus) and shadscale stands in the southern portion of the project area (e.g., south of 

I-80). 

9

 The baseline data for the primary vegetation cover types were provided by Aero-graphics, Inc. (Salt Lake City, UT). The sub-meter 

aerial photographs were acquired with a fixed-wing aircraft flying at an altitude of 12,000 feet above ground level during the week 

of June 19–23, 2006. The aerially-acquired data were digitized and ortho-rectified by Aero-graphics. The final digitized data were 

processed by Hayden-Wing Associates LLC using ArcGIS®

 Version 9.1. 

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Map 3.6-2. Major land cover types within the CD-C project area 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

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CHAPTER 3—AFFECTED ENVIRONMENT—VEGETATION
 

3.6.2.1 Mountain Big Sagebrush Cover Type and Subtype Inclusions 

In the past, studies have identified Artemisia tridentata spp. vaseyana as mountain big sagebrush. 

However, recent investigations (Goodrich et al. 1999, Tart and Winward 1996) recognize two varieties of 

this subspecies, vaseyana and pauciflora. Numerous field investigations by Hayden-Wing Associates 

LLC (HWA) throughout Wyoming have found these two varieties are morphologically similar in growth 

form and are usually intermixed in the same habitat. Therefore, in the project area, these two varieties 

have been mapped as one type and will be hereafter referred to as mountain big sagebrush (ATVP). 

ATVP occupies approximately 54,606 acres within the project area, or about 5.1 percent of the project’s 

total land surface area (Table 3.6-1). 

Throughout the Intermountain West, ATVP is found at elevations from 3,500–9,800 feet and occurs from 

foothills to subalpine zones. Annual precipitation ranges from 12–30 inches. Soils on which mountain big 

sagebrush grows range from slightly acid to slightly alkaline and are generally well-drained. Soil moisture 

is usually favorable throughout the growing season. A large number of grass, forb, and shrub species 

grow in association with this shrub and usually produce an abundance of forage. Open stands with good, 

diverse understory are essential to sage-grouse, and such sites can be used in treatment projects to 

maintain sufficient shrub density and cover for sage-grouse. It is essential that desirable understory 

species and woody species associated with mountain big sagebrush be retained or reestablished as part of 

the reclamation effort. 

The lower-elevation range of ATVP on the project area is about 6,500–6,800 feet. ATVP plant density 

(stems per unit area) increases and plant form becomes more robust at about 6,900 feet. These attributes 

are more noticeable on the leeward side of north/south-oriented ridgelines and hogbacks where 

topographic features are favorable for extensive snow deposition and retention. The more robust stands 

appear to be closely associated with the higher elevations along the west rim of the Continental Divide 

which bisects the project area near Wamsutter, and in the Flat Top Mountain complex in the southern 

portion of the project area. 

The southern and southwestern portions of the project area include the Flat Top Mountain complex (Flat 

Top Mountain, East Flat Top Mountain, North Flat Top Mountain, and West Flat Top Mountain) and 

Robbers Gulch areas, where higher elevations and a greater moisture regime provide suitable habitats for 

ATVP and mountain mixed-shrub communities. North Flat Top Mountain in the NW 1⁄4 Section 2, T14N, 

R93W is the highest topographic feature in the project area with an altitude of 7,822 feet. It is at these 

greater elevations with deeper soils that ATVP can grow to over 40 inches tall and become so dense that 

it is difficult to walk through the stand. 

Common grass species associated with the ATVP cover type include: 

 Bluebunch wheatgrass (Pseudoroegneria  Mutton bluegrass (Poa fendleriana) 

spicata)  Needle-and-thread (Hesperostipa comata) 

 Bottlebrush squirreltail (Elymus  Oniongrass (Melica bulbosa) 

elymoides)  Prairie junegrass (Koeleria cristata) 

 Green needlegrass (Nassella viridula)  Spike fescue (Leucopa kingii) 

 Idaho fescue (Festuca idahoensis)  Thickspike wheatgrass (Elymus 

 Little bluegrass (Poa secunda) macrourus) 

Common understory shrubs may include green (Douglas) rabbitbrush (Chrysothamnus viscidiflorus), gray 

(rubber) rabbitbrush (Ericameria nauseosa), and snowberry (Symphoricarpus oreophilus), with lesser 

densities of antelope bitterbrush (Purshia tridentata) and serviceberry (Amelanchier alnifolia). The 

increased average annual precipitation at these ATVP sites provides suitable habitat for a diverse and 

abundant forb component. Frequently observed forb species include the following: 

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 Arrowleaf balsamroot (Balsamorhiza  Indian paintbrush (Castilleja spp.) 

sagittata)  Phlox (Phlox multiflora)
 

 Beardtongue (Penstemon spp.)  Sego lily (Calochortus nuttallianum)
 

 Bluebells (Mertensia spp.)  Silky lupine (Lupinus sericeus) 

 False dandelion (Agoseris glauca)  Sulphur buckwheat (Eriogonum 

 Geranium (Geranium richardsonii) umbellatum) 

 Groundsel (Senicio spp.)  Wild onion (Allium spp.)
 

The mixed mountain-shrub cover type is similar to the mountain big sagebrush described above, with the 

distinction that mountain-shrub species must comprise 5 percent or more of the canopy cover to be 

classified as a mixed mountain-shrub cover type. Mixed mountain-shrubs occur in the Flattop Mountain 

complex, especially on the north and east aspects, but ATVP is the dominant shrub species at all these 

locations. 

Chemical treatment of late successional, dense stands of ATVP in the project area has been conducted by 

the RFO to reduce sagebrush density and increase herbaceous production. Thinning of ATVP with low 

rates of the herbicide tebuthiuron has been demonstrated to enhance herbaceous plant production, 

community structure, ecosystem functioning, and biodiversity (Olson and Whitson 2002). The concept of 

sagebrush “thinning” was developed at the University of Wyoming and has been shown to have broad 

applications in rangeland environments, including restoration projects. 

Wildfires and prescribed fires both occur in the ATVP cover type. Mountain big sagebrush is highly 

susceptible to injury from fire, and plants are readily killed in all seasons, even by light-severity fires 

(Blaisdell 1953, Blaisdell et al. 1982, Neuenschwander 1980). Without rest or post-burn grazing 

management, sagebrush cover may return to pre-treatment levels. Lesica et al. (2007) examined 38 sites 

in southwestern Montana and found that average post-fire time to full recovery for mountain big 

sagebrush was about 32 years. Monitoring of prescribed burns of ATVP with rest or deferment after 

burning in Carbon County indicates sagebrush recovery may take up to 50 years to reach pre-burn levels 

(Warren 2004). 

3.6.2.2 Wyoming Big Sagebrush Cover Type and Subtype Inclusions 

Wyoming big sagebrush (ATW) is the dominant vegetation cover type in the project area and occupies 

approximately 417,572 acres or about 39 percent of the project’s total land surface area (Table 3.6-1). 

The ATW subspecies can be found throughout the Intermountain West on xeric sites, foothills, valleys, 

and mesas between 2,500 and 7,000 feet. Annual precipitation varies from 7–15 inches. Soils on which 

ATW occur are usually well-drained, gravelly to stony, and may have low water-holding capacity. Soils 

are shallow, usually less than about 18 inches deep. Fewer herbaceous species are associated with 

Wyoming big sagebrush than with ATT or ATVP. Native bunchgrasses are often important understory 

species in ATW communities. 

ATW occurs in almost an infinite number of communities and associations. Since the plants are almost 

totally dependent upon moisture received through infiltration and percolation of snow or rain water, their 

size and productivity responds as a direct result to moisture availability as influenced by soil, chemical, or 

other site criteria. The ATW communities with vigorous and productive plants are often located in 

depressions/swales protected from wind. These sites have a relatively deep and porous soil. Open, windblown sites normally have a thin, A Horizon topsoil layer. The plants are sparse, small in stature, and 

exhibit limited productivity. Fisser (1972) identified three recognizable ATW sub-community 

classifications based on obvious plant heights: 

1. Arid – average height about 10–12 inches; 

2. Intermediate – average height about 12–18 inches; and 

3. Mesic – average height about 18–24 inches. 

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CHAPTER 3—AFFECTED ENVIRONMENT—VEGETATION
 

Healthy and vigorous ATW plants located in ideal growing sites can attain a height of 40 inches. 

An estimate of the elevation range for ATW in the project area indicates it is the dominant sagebrush 

subspecies below an elevation of about 6,500 feet. This elevation is about the same as the lower-elevation 

limit of ATVP. Therefore, it becomes apparent that in most cases, the transition zone between these two 

taxa is not well-defined and may occur over a distance of several miles depending mainly on parent-soil 

characteristics, snow-deposition patterns, slope, and aspect. 

The most common grasses associated with the ATW cover type include the following: 

 Bottlebrush squirreltail  Needle-and-thread 

 Indian ricegrass (Achnatherum  Thickspike wheatgrass 

hymenoides)  Western wheatgrass (Pascopyrum smithii) 

 Little bluegrass  Threadleaf sedge (Carex filifolia) 

Other shrubs often associated with this cover type are typically as follows: 

 Broom snakeweed (Gutierrezia sarothrae)  Spiny hopsage (Grayia spinosa) 

 Cotton horsebrush (Tetradymia canescens)  Plains prickly-pear cactus (Polyacantha 

 Gray rabbitbrush opuntia) 

 Green rabbitbrush  Winterfat (Krascheninnikovia lanata) 

 Shadscale 

Forbs are less common than in other sagebrush communities due to the more arid environment. However, 

the most frequently observed species include the following: 

 Beardtongue (Penstemon spp.)  Locoweeds (Oxytropis spp.) 

 Goldenweed (Happlopappus ssp.)  Long-leaf phlox (Phlox longiloba) 

 Hood’s phlox (Phlox hoodii)  Low buckwheat (Erigonum ovalifolium) 

 Hollyleaf clover (Trifolium gymnocarpum)  Spring parsley (Cymopterus acaulis) 

 Hooker’s sandwort (Arenaria hookeri)  Wild onion (Allium spp.) 

An Artemisia taxon closely related to ATW (Winward 1991a) was identified north of the Chain Lake 

Flats area. This currently undescribed taxon is tentatively known as Gosiute big sagebrush and is thought 

to be a hybrid between ATW and ATV var. pauciflora (Winward 1999). The distribution of this hybrid 

Artemisia is believed to be closely associated with the shoreline soils of the ancient paleolake Gosiute in 

Wyoming (Winward 1999). A map of the approximate shoreline of Lake Gosiute during the Eocene 

(Dyni 1996) indicates the eastern extent of its shoreline was approximately near Creston Junction and 

extended northwest into Sweetwater County, crossing the Chain Lakes area. At its maximum extent, Lake 

Gosiute covered about 15,000 mi2

 (Dyni 1996). Gosiute big sagebrush has many unique characteristics 

that are described more fully by Bennett (2004). 

On gravelly to rocky, shallow sites, both bluebunch wheatgrass and black sagebrush (A. nova) are found 

in addition to a greater density of cushion plants. This subtype inclusion may be observed at certain 

locations along Red Creek Road in the northern portion of the project area. The black sagebrush present is 

the light form of the genus. Other sub-type inclusions in the ATW cover type include small, open areas 

dominated by bud sagebrush (Picrothamnus desertorum) such as that found on the plateau area north of 

Lost Creek Basin. The most diverse ATW sub-type inclusions observed are associated with the many 

small, stabilized sand dunes that occur in the western and northern portions of the project area. These 

dunes are associated with similar dunes found in the Sand Hills, Ferris Mountains, and the Killpecker 

Sand Dune areas. When the dune is oriented perpendicular to the westerly winter wind, it is not 

uncommon to observe arid-adapted species such as ATW, spiny hopsage, and prickly-pear cactus on the 

western aspect of the dune slope and mesic forms such as basin big sagebrush and greasewood on the 

leeward side where snow deposition provides greater water availability. The dune sites with the greatest 

vegetation diversity occur near the south shore of the several small lakes in the Chain Lakes area where it 

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is not uncommon to observe budsage, ATW, Wood’s rose, shadscale, spiny hopsage, fringed sage (A. 

filifolia), greasewood, and green rabbitbrush growing together, intermixed with grasses and forbs in a 

very small area. 

The value of ATW as an important winter browse species cannot be overemphasized. Mule deer 

preference for sagebrush species as winter forage is well-documented (Sheehy and Winward 1981, 

Wambolt 2004). Nelson et al. (1994) found that ATW in the winter diets of mule deer in the Baggs 

Habitat Unit comprised approximately 74 percent of the total diet. DeBolt (2000) found ATW made up 

more than 70 percent of mule deer diets on winter ranges west of WY 789. ATW is also an important 

food item for greater sage-grouse (Centrocercus urophasianus) and taller stands have been shown to 

serve as severe winter relief (SWR) habitat for these birds during winters of record-breaking snowfall 

such as occurred during the winter of 2000–01 (HWA 2004) and 2010–11 (WRCC 2012). 

The sagebrush “thinning” concept discussed in the mountain big sagebrush sub-section (3.6.2.1) has also 

been employed by the RFO to reduce ATW density and increase herbaceous production in the Tipton and 

Flattop areas of the CD-C project area. 

Wildfire is not common in the ATW cover type due to the low quantity of fine fuels in the shrub’s 

interspaces that can support and carry a fire. However, in extreme weather conditions (e.g., low humidity, 

high temperatures, and strong winds) such as was common during the 2000 fire season, fire was observed 

to carry rapidly through a sparse ATW stand west of Medicine Bow, Wyoming (Bennett 2004). 

Following fire or other major disturbance, herbaceous species will dominate the treatment site and 

recovery to 20 percent canopy cover may take more than 40 years (Young and Evans 1989, Winward 

1991b). Site reestablishment is by seed bank, seed production from remnant plants, and seeds from 

adjacent plants outside of the burn area. Discontinuity of fuels in ATW communities usually results in 

mosaic burn patterns, leaving remnant plants for seed (Bushey 1987). Overall fire return intervals in 

ATW appear to have ranged from 10–240 years or more (Winward 1991b, Bunting et al. 1987, Young 

and Evans 1989). Reviewers for the Rapid Assessment Reference Condition Model component of the 

LANDFIRE project (www.landfire.gov) disagreed about average fire-return intervals in the ATW 

vegetation group, but agreed the mean fire intervals of 90–140 years were probably realistic (Schmidt et 

al. 2002). 

3.6.2.3 Basin Big Sagebrush Cover Type 

Basin big sagebrush (ATT) occupies approximately 7,157 acres within the project area or about 0.7 

percent of the project’s total land surface area (Table 3.6-1). ATT typically occurs on the deeper, welldrained soils usually found along ephemeral and intermittent drainages, floodplains, and leeward slopes 

where water availability is greater than on adjacent uplands. It is often co-dominant with greasewood at 

certain sites and may occur as small inclusions in the ATW and ATVP cover types. Bennett (2004) found 

that heights of ATT are a good measure of site suitability. More arid sites produce plants that average 

about 23 inches in height, intermediate sites about 29 inches and mesic sites greater than 62 inches. At 

ideal sites such as found along the Muddy Creek drainage, ATT often grows to 10 feet in height, and 

plants attaining 13 feet in height have been recorded along the Green River in Sublette County (Bennett 

2004). Palatability of ATT is generally considered lower than ATW (Rosentreter 2005). This 

phenomenon was observed by the Rawlins BLM staff during the harsh winter of 1983–84 in the Muddy 

Creek area. They found that mule deer use of ATW was severe compared to marginal use of ATT, even 

though animals were starving and winter mortality reached 50 percent in some Herd Units (Warren 2004). 

Common understory species in the ATT cover type include the following: 

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 Aster  Locoweed 

 Basin wildrye (Leymus cinereus)  Lupine 

 Bluebell  Louisiana sagewort (A. ludovicianna) 

 Buttercup  Povertyweed (Iva axillaris) 

 False dandelion  Snowberry 

 Golden currant (Ribes aureum)  Thickspike wheatgrass 

 Gray rabbitbrush  Violet 

 Green rabbitbrush  Wild onion 

 Kentucky bluegrass (Poa pratensis)  Wood’s rose (Rosa woodsii) 

 Little bluegrass 

Wildfires and prescribed burns both occur in this cover type. Where other species are uncommon or 

without post-burn grazing management, sagebrush cover may return to pre-treatment levels in 15–20 

years. However, monitoring of prescribed burns with rest or deferment after treatment indicate ATT 

recovery may take up to 50 years to attain pre-treatment levels. 

The recent prolonged drought in south-central Wyoming has had a severe effect on ATT. The majority of 

the sagebrush die-backs and die-offs observed at present in the project area occur in ATT and ATVP 

stands, both of which depend on perennial mesic conditions for growth, reproduction, and survival. The 

heaviest mortality has been observed to occur along ephemeral channels in heavier soils where water 

availability is usually good to excellent in normal years. The most robust plants are currently associated 

with higher-elevation sandy loam soils on the leeward (usually east) side of slopes where snowdrifts 

accumulate, thereby increasing water availability. The same beneficial effect can be seen on the leeward 

side of the many snow fences in the project area, especially along I-80 and WY 789. 

3.6.2.4 Juniper Woodland Cover Type 

The juniper woodland cover type occupies about 536 acres on the project area or about 0.05 percent of the 

project’s total land surface area (Table 3.6-1). Utah juniper (Juniperus osteosperma) is the dominant tree 

within this cover type. The preferred habitat of Utah juniper is usually associated with shallow, rocky soil 

with a fractured rock substrate, where the tree can root down to and take advantage of collected water. 

Juniper will also encroach into adjacent sagebrush stands. This can be seen west of the Bluffs in the 

extreme southern end of the project area, north of Baggs along the west side of WY 789. In April 2007, 

several hundred mule deer were seen daily on the cuesta west of the bluffs. They appeared to be using the 

tree area for bedding and thermal cover during the day and then trailing down the slopes to the Muddy 

Creek drainage for food and water at night. The dominant sagebrush taxon on the cuesta is ATVP, which 

is ranked as more palatable than ATW and ATT (Rosentreter 2005). 

Common understory species associated with this cover type include the following: 

 Beardtongue  Groundsel 

 Bitterbrush  Indian ricegrass 

 Black sagebrush  Little bluegrass 

 Bluebunch wheatgrass  Miner’s candle (Cryptantha ssp.) 

 Canby bluegrass (Poa canbyi)  Phlox 

 Goldenweed  Twin bladderpod (Physaria ssp.) 

When stands of Utah juniper become too dense, the understory of native grasses and forbs dies out and is 

usually replaced by invasive species such as downy brome (Bromus tectorum) and annual forbs. Fire can 

be a useful tool in reducing juniper overstory and maintaining understory cover and composition. Where 

the understory is too sparse to carry a fire, some form of mechanical treatment may be required to restore 

species diversity. A great number of Utah juniper in this area were logged to produce charcoal for the 

Union Pacific Railroad (UPRR) smelters in Rawlins in the 1870s–80s (Bennett 2004). 

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CHAPTER 3—AFFECTED ENVIRONMENT—VEGETATION
 

3.6.2.5 Greasewood Flats and Fans 

The greasewood cover type occupies approximately 246,273 acres within the project area or about 23 

percent of the project’s total land surface area (Table 3.6-1). Greasewood is a native, deciduous perennial 

shrub and can attain heights of 8 feet under ideal growing conditions. 

Greasewood inhabits a wide range of plant communities within the project area. Plants are typically found 

growing in saline soils that can be quite moist (wet saline meadows) to dry uplands. Greasewood is often 

the dominant species in the plant community, but plants are also found associated with saltbush, saltgrass, 

shadscale, and ATT and ATW sagebrush communities. Ideal habitat for greasewood within the project 

area is often located on saline valley bottoms (e.g., Muddy Creek floodplain) and on salt-bearing shale 

outcrops in canyons and on foothills. Sites vary in respect to soil texture and availability of groundwater. 

Some sites are wet with high water tables, and others are dry with well-drained soils. Greasewood occurs 

in the project area as smaller, mixed stands to large, monotypic stands. The latter were observed in several 

large saline basins located in the northern portion of the project area (e.g. Lost Creek and Red Desert 

Basins). Greasewood can be found at all elevations of the project area. It often encroaches into the big 

sagebrush and saltbush cover types, especially where additional moisture is available, such as on the 

many vegetated sand dunes in the southwestern portion of the project area (e.g., north of Mexican Flats). 

Greasewood is the dominant shrub associated with the large, vegetated sand-dune complex extending 

west to east across the northern portion of the area. The most extensive vegetated dune complex is located 

in T23N:R97W and T23N:R96W. Within this complex, several active dunes are also present. The 

established greasewood in this sandy area serve as a valuable soil stabilizer by decreasing wind and water 

erosion. Black greasewood is also the dominant shrub species in the Chain Lakes region in the northern 

portion of the project area. An unusual greasewood growth form was observed in the vicinity of the 

several small lakes in this area. The usual upright stature of the plant has been replaced by a low, 

prostrate, spreading form which rarely exceeds 10–12 inches in height. It is unknown at the present time 

if this is an ecotypic adaptation or if the plants represent a different subspecies. Greasewood distribution 

and abundance in the southern portion of the project area is greatest along portions of the Muddy Creek 

floodplain corridor and in a large, flat basin immediately north of the Mexican Flats area. 

The palatability of greasewood in Wyoming is reported as fair for cattle, domestic sheep, horses, 

pronghorn, mule deer, and small mammals, and as poor for elk, white-tailed deer, small non-game birds 

and waterfowl (Dittberner & Olson 1983). Poisonous oxalates, found in the leaves, have caused mortality 

in sheep. Cattle are rarely poisoned, but spines are reported to puncture the rumen (the first chamber of 

the alimentary canal). Greasewood understory composition is not as diverse as in the big sagebrush cover 

types. 

Common understory species in the black greasewood cover type include the following: 

 Basin wildrye  Inland saltgrass (Distichlis spicata) 

 Biscuitroot  Little bluegrass 

 Bottlebrush squirreltail  Western wheatgrass 

 Gardner’s saltbush  Wild onion 

3.6.2.6 Saltbush Flats and Fans and Sub-type Inclusions 

Gardner’s saltbush (saltbush) is a native, spreading, low-growing, evergreen perennial sub-shrub and 

grows from 8–20 inches in height (McArthur et al. 1978). Saltbush is the third-largest primary cover type 

on the project area following the ATW and black greasewood cover types at 172,699 acres or about 16 

percent of the project’s total land surface area (Table 3.6-1). 

This cover type is found on saline soils in small to large openings or can occur as “stringer” inclusions 

within the ATW or greasewood primary cover types. These saltbush stands are sparsely vegetated and 

bare soil often exceeds 60 percent of the total ground-cover. Average vegetative stem height of saltbush 

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CHAPTER 3—AFFECTED ENVIRONMENT—VEGETATION
 

on the project area ranges from 4–10 inches but several robust plants in the 16- to 18-inch range were 

observed south of the Chain Lakes area along Riner Road. Saltbush reproductive stems were observed to 

be particularly abundant during the 2007 growing season at all sites within the project area. 

The largest monotypic saltbush communities within the project area are located in the Mexican Flats area. 

However, the northern portion of the project area also contains several sizable communities, and 

mountain plovers (Charadrius montanus) were observed at all locations where this cover type was 

dominant. The most common sub-type inclusion in this cover type is birdfoot sagebrush (A. pedifidita) 

which may occur as a pure stand or, more typically, intermixed with the saltbush plants. 

The persistent leaves of saltbush provide nutritious winter forage for livestock and wildlife species 

throughout its range (Nord et al. 1969). It is particularly important for domestic sheep because it provides 

the minimum nutritional maintenance requirement for gestating ewes (Fisser & Joyce 1984). 

Other common plant species associated with this cover type include the following: 

 Biscuitroot  Plains prickly-pear cactus 

 Western wheatgrass  Threadleaf sedge (most common associate 

 Bottlebrush squirreltail on the project area) 

 Little bluegrass  Wild onion 

 Indian ricegrass  Winterfat 

Commonly observed inclusions in the saltbush and desert shrub vegetation types are cushion plant 

communities. Cushion-plant vegetation is found on suitable sites scattered across much of the project 

area. In the cushion growth form, stems and leaves are densely aggregated near ground level, probably to 

reduce the stresses of severe environmental conditions (e.g. cold, high winds, desiccation). Cushion-plant 

vegetation has been divided into two broad categories—alpine and lowland—with completely different 

species compositions (Knight 1994). The lowland type is found on RFO lands. 

According to Jones (2005), a “cushion-plant” is typically defined as a prostrate, acaulescent (having no 

stem or only a very short stem), tap-rooted forb that typically grows in a dense mat. Examples can be 

found in a number of plant families and include Arenaria hookeri (Caryophyllaceae), Astragalus 

spatulatus (Fabaceae), Erigeron composites (Asteraceae), Eriogonum acaule (Polygonaceae), Draba 

oligosperma (Brassicaceae), and Phlox muscoides (Polemoniaceae). Cushion-plant vegetation is the short, 

often sparse vegetation on rims and outcrops formed in resistant bedrock, where cushion-plants contribute 

a major proportion of the plant canopy cover. Arenaria hookeri and Pseudoroegneria spicata are almost 

always present in the cushion-plant vegetation and often contribute a substantial amount of the canopy 

cover. At many sites, these species are joined by Phlox muscoides (a cushion-plant) as a dominant or codominant. Elsewhere, P. muscoides is absent, and a number of other cushion-plants (Astragalus 

spatulatus, Astragalus simplicifolius, Tetraneuris acaulis, Stenotus armerioides) or non-cushion forbs 

(especially Phlox hoodii) are regularly present and sometimes contribute much of the canopy cover (Jones 

2005). 

The concept of cushion-plant vegetation usually excludes sparse vegetation dominated by non-cushion 

forbs or sub-shrubs (such as Atriplex nuttallii or Artemisia pedatifida) that occurs on soft bedrock. In the 

field, the Wyoming Natural Diversity Database (WYNDD) defines cushion-plant vegetation as vegetation 

in which cushion-plants are estimated to contribute at least 50 percent of the canopy cover and the grasses 

and shrubs common in the surrounding shrub-steppe vegetation contributes less than 50 percent of the 

canopy cover (Jones 2005). 

3.6.2.7 Mixed Desert-Shrub 

The mixed desert-shrub cover type occupies approximately 142,062 acres on the project area or about 13 

percent of the project’s total land surface area (Table 3.6-1). The mixed desert shrub cover type as 

described in this document is a mixture of shrubs and sub-shrubs occurring in dry, saline upland habitats. 

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Shrub cover is often dominated by shadscale but can be a mixture of saltbush, black greasewood and/or 

desert cushion plants. Several small sites were observed in the northern portion of the project area along 

Red Creek Road where bud sage (Picrothamnus desertorum) is the dominant shrub with plants reaching 

10 inches in height with a robust form which is unusual for this species in Wyoming. A herbaceous 

understory of forbs and grasses is usually present within this cover type and biological soil crusts are 

usually present on the soil surface. This cover type exhibits three phases including: (1) sites dominated by 

sagebrush, (2) sites dominated by saline-tolerant shrubs such as greasewood and saltbush, and (3) 

discontinuous areas devoid of woody shrubs, but with the same herbaceous understory components 

characteristic of shrub-covered areas. As with the saltbush vegetation cover type, cushion plant 

communities are often observed in the mixed desert shrub cover type. 

Common herbaceous ground-cover species in desert shrub communities include the following: 

 Bluebunch wheatgrass  Needle-and-thread grass 

 Buckwheat  Plains prickly-pear 

 Common yarrow (Achillea millefolium)  Sandberg bluegrass 

 Indian paintbrush (Castilleja spp.)  Threadleaf sedge 

 Indian ricegrass  Western wheatgrass 

In addition to sagebrush, other shrubs commonly observed in this cover type often include the following: 

 Gray rabbitbrush  Spiny hopsage 

 Green rabbitbrush  Spiny horsebrush 

 Shadscale 

3.6.2.8 Vegetated Sand Dunes 

Vegetated sand dunes occupy approximately 276 acres within the project area, or about 0.03 percent of 

the project’s total land surface (Table 3.6-1). The largest sand-dune complex in the project area is in the 

northern portion of the project area and primarily located in T23N:R97W and T23N:R96W in Sweetwater 

County, north of County Road (CR) 67 and CR 20. Several dunes in this complex are currently active and 

vegetation is absent. Many smaller, vegetated dune sites are located throughout the west-central portion of 

the project area west of Dad and near the southern edge of the Chain Lakes area. Greasewood is the 

dominant shrub on many of these dunes and serves as a valuable soil stabilizer by decreasing wind and 

water erosion. A recent investigation of the Killpecker sand dune area in southwest Wyoming by Mayer 

and Mahan (2004) found that the age of eolian sand (15,000 years before present [B.P.]), combined with 

those of Folsom (12,950–11,950 years B.P.) and Agate Basin artifacts (12,600–10,700 years B.P.) 

overlying eolian sand, indicates the dune field existed at least during the late Pleistocene. 

These unique sites provide micro-environments that allow for greater plant diversity than adjacent upland 

sites. Steidtmann (1973) found that snow may become incorporated in eolian sand dunes of southwestern 

Wyoming when snow cornices on dune crests begin to melt, slide down the lee slope, and are covered by 

sand during subsequent lee-slide deposition. In some cases burial is rapid enough to provide the insulation 

necessary to preserve the ice and snow within the dune throughout the year. The smaller dunal areas such 

as those found west of Dad are predominantly oriented perpendicular to the westerly prevailing winter 

wind, forming natural snow-breaks that trap snow on their leeward side. It is not uncommon to observe 

ATW (arid form), spiny hopsage, and prickly-pear cactus on the western aspect and ATW (mesic form), 

ATT, and greasewood on the leeward side of these smaller, stabilized sand dunes. 

The small dune sites south of the Chain Lakes complex often occur within other primary cover types (e.g., 

ATW and saltbush) and form hummocks covered with a diverse shrub and herbaceous understory very 

different than the surrounding vegetation. At several sites it was observed that a combination of budsage, 

ATW, shadscale, spiny hopsage, fringed sage, greasewood, and green rabbitbrush intermixed with grasses 

and forbs were all occupying these small hummocks. 

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3.6.2.9 Riparian Cover Types 

The riparian/wet-meadow cover type occupies about 1,004 acres on the project area or about 0.10 percent 

of the project’s total land surface area (Table 3.6-1). Riparian sites often occur as narrow corridors 

traversing many different plant zones. Streams and drainages often occupy very small but important sites 

within major land types. The vegetation and habitat provided by the riparian zone is extremely important 

to the management of associated lands. Riparian sites attract and sustain livestock and wildlife and are 

particularly important during the midsummer months. The recent extended drought has concentrated the 

use of riparian sites by livestock, wildlife, and wild horses—usually with deleterious effects. The two 

allotments that did not meet Standard # 2 (Riparian/Wetland Health) of the Standards for Public Land 

Health (See Section 3.6.3.) were the Cyclone Rim (10103) and Jawbone (00709) allotments. The Cyclone 

Rim allotment failed the Standard because of non-functional or Functioning-At-Risk springs and seeps. 

Identified causes included previous excessive use by wild horses during the growing season, often 

complicated by livestock grazing (BLM 2001a). There is only one permanent water source (Mud Springs) 

in the Jawbone allotment (23,000 acres/9,307 ha.) in addition to one well and ten semi-reliable reservoirs. 

Summer cattle use was identified as the primary factor affecting the wetland habitat/vegetation in this 

allotment. Since the 1998-2000 PFC evaluations, fencing and off-site water development have been 

installed at many of these sites (BLM 2001a). 

Riparian communities often provide diversity to otherwise rather barren and exposed wildlands. Riparian 

habitat within the project area occurs along perennial and intermittent drainages, around seeps and 

springs, and around man-made reservoirs. Although small in extent, these areas are the most productive of 

all vegetation types and therefore are extremely important for wildlife habitat and livestock forage. 

The major drainage in the southern portion of the project area is Muddy Creek (HUC 14050004). Muddy 

Creek is described as a high-elevation, cold-desert stream originating in the Sierra Madre Range east of 

the project area and terminating at its confluence with the Little Snake River near Baggs, Wyoming. 

Upstream from this confluence, numerous unnamed ephemeral channels and named draws flow into 

Muddy Creek. 

The northern portion of the project area generally drains into the Great Divide Basin (HUC 14040200) via 

Separation Creek. The Great Divide Basin is a closed basin bounded by the Continental Divide on all 

sides and has no hydrologic outlet (Seaber et al. 1987). The Great Divide Basin is a relatively shallow 

depression with isolated buttes, pan-like depressions, and sparse vegetation. Numerous ephemeral streams 

flow toward the center of the Basin before disappearing into the soil or man-made impoundments. The 

Chain Lakes complex is located approximately 32 miles northwest of Rawlins. Two large lakes and 

several small lakes extend from west to east across the flats. This general area supports greater sagegrouse, migratory waterfowl, and shorebirds, and provides winter habitat for pronghorn. Small bands of 

wild horses from the Lost Creek Herd Management Area (HMA) are commonly observed in this part of 

the project area. 

Riparian/wetland habitat within the project area can be defined and described in the following groups: 

desert springs and seeps, and streams supported by them; playa lakebeds; wetlands in the Chain Lakes 

area; and man-made wetlands around artesian wells. Streams in the area generally flow short distances 

supporting riparian vegetation before turning into ephemeral/intermittent drainages that do not support 

riparian vegetation. A good example is Lost Creek which is fed by Eagle’s Nest Spring. Riparian 

conditions exist above the Red Creek Road culvert before the stream disappears underground. However, 

from the culvert and continuing to Lost Lake, the creek’s stream bed is normally dry and its riparian 

corridor supports mainly greasewood and non-riparian vegetation. The Lost Creek drainage corridor was 

observed to provide excellent pygmy rabbit habitat and appears to be a major travel route and bedding 

area for elk from the Red Desert Migratory Elk Herd. Three to seven head of elk were consistently seen in 

this area during Apri – May, 2007. The Lost Creek streambed below Eagle’s Nest Spring was 

documented by HWA to contain persistent sepal yellowcress (Rorippia calcycina), a BLM-designated 

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CHAPTER 3—AFFECTED ENVIRONMENT—VEGETATION
 

special status plant species. The 2006 and 2007 HWA special status plant species survey results are 

available as a separate Technical Report (HWA 2008a). 

Riparian grassland habitat types are the most common forms of vegetation found within riparian areas in 

the project area. Riparian grasslands are wetland-, stream-, or spring-associated grass and grass-like 

communities, which are maintained by a water table within rooting depth during most of the growing 

season. Common species include the following: 

 Alkali sacaton (Sporobolus airoides)  Liddon sedge (C. petasata) 

 Asters  Mat muhly (Muhlenbergia richardsonis)
 

 Baltic rush (Juncus balticus)  Mint (Mentha spp.)
 

 Basin wildrye  Nebraska sedge (Carex nebrascensis) 

 Beaked sedge (C. utriculata)  Redtop (Agrostis stoloifera)
 

 Cinquefoil (Dasiphora floribunda)  Spike sedge (C. nardina) 

 Horsetail (Eqisetum arvense)  Thistle 

 Inland saltgrass (Distichlis spicata)  Tufted hairgrass (Deschampsia caespitosa)
 

 Kentucky bluegrass  Wheatgrass
 

The majority of the project area consists of ephemeral drainages (washes, draws, gullies) which flow only 

in response to snowmelt in early spring or as a result of summer precipitation events which are usually of 

short but intense duration. Soil erosion may be severe where erosion devices are not present or ground 

cover is sparse. 

The most prominent natural wetland system in the northern portion of the project area is the Chain Lakes 

complex. These lakes and adjacent habitats support riparian grassland and open aquatic-emergent wetland 

habitats. Within these alkaline wetlands, the shallow pools where salts accumulate are the harshest 

growing environment for plants. Plants must tolerate not only standing water in spring, but also dry and 

extremely alkaline soils in late summer. Stunted, scattered plants of arrowgrass (Triglochin spp.), an 

exceedingly salt-tolerant, grass-like forb, are frequently the sole inhabitants of these highly alkaline 

depressions. Alkali plantain (Plantago eriopoda) and inland saltgrass can survive in less alkaline 

depressions. Like most halophytes (plants adapted to grow on salty soils) these plants have the ability to 

accumulate higher concentrations of salts in their cell sap than salt concentrations in the soil water. By 

concentrating salts, these halophytes can draw soil water into their roots, since water generally flows from 

areas of low salt concentration to areas of higher salt concentrations 

Plant species in these areas are saline/alkali tolerant and may include: 

 Alkali plantain  Hairy goldaster (Heterotheca villosa) 

 Alkali saltgrass (Distichlis stricta)  Nuttal’s alkaligrass (Puccinellia 

 American bulrush (Schoenoplectus nuttalliana) 

americanus)  Rocky Mountain glasswort (Salicornia 

 Arrowgrass rubra) 

 Baltic rush  Sea milkwort (Glaux maritima) 

 Buttercup  Slim sedge (Carex praegracilis) 

 Cinquefoil (Potentilla spp.)  Tufted hairgrass (Deschampsia caespitosa) 

 Greasewood 

The Chain Lakes wetlands also provide habitat for meadow milkvetch (Astragalus diversifolius var. 

diversifolius), recently discovered in 2008 by the WYNDD (Heidel 2008). The species has now been 

documented in three extant occurrences in south-central Wyoming, totaling approximately 8,000 plants 

within about 187 acres, near the Chain Lakes region of the project area (Heidel 2009) and was recently 

added to the BLM sensitive plant list (BLM 2010) (see Section 3.9.2.3 Sensitive Plant Species). 

Man-made wetlands occur primarily next to artesian wells and reservoirs or pits. Wetlands supported by 

artesian wells are mostly composed of sedges, bulrushes, and several grass species. Many reservoirs and 

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CHAPTER 3—AFFECTED ENVIRONMENT—VEGETATION
 

pits in the project area do not hold water on a year-long basis and the perennial drought that began with 

the 2000 growing season has had negative effects on water-storage capabilities and wetland vegetation 

health. 

An extensive wetland complex known as the George Dew/Red Wash Wetland Complex is located near 

Dad about 25 miles north of Baggs, west of and adjacent to WY 789. This site encompasses 

approximately 6 miles of willow-dominated (Salix sp.) riparian corridor along Muddy Creek with 

associated floodplain and meadows ranging from 0.25 to 0.75 mile wide, constructed and natural 

impoundments, and adjacent upland sites dominated by greasewood, sagebrush, and Gardner saltbush. 

The George Dew/state land wetlands project is within the Muddy Creek Wetland Complex. The wetland 

component of this project was designed to protect and enhance about 1,100 acres of existing wetlands and 

create 125 acres of new wetlands (Wyoming Riparian Association 1997). 

3.6.2.10 Basin Grassland 

The basin grassland vegetation cover type occupies approximately 5,122 acres within the project area or 

about 0.5 percent of the project’s total land surface area (Table 3.6-1). This cover type is found in 

scattered park-like patches throughout the project area. Shrubs such as the native rabbitbrushes, winterfat, 

and various sagebrush species and subspecies may be present but cannot occupy more than 25 percent of 

the total ground cover to be classified as basin grassland. Herbaceous species often include western 

wheatgrass, blue grama, needle-and-thread, threadleaf sedge, Sandberg bluegrass, and prairie junegrass. 

Plains prickly-pear is also commonly observed in this cover type. 

3.6.2.11 Non-vegetated Cover Type―Bare Ground 

Bare ground on the project area accounts for approximately 4,117 acres or about 0.4 percent of the 

project’s total land surface area (Table 3.6-1). Bare ground, as defined in this EIS, contains less than 7.5 

percent vegetated ground cover. The soils in these relatively low-production areas and underlying parent 

materials are very soft and highly erosive, and the landscape is cut with a large number of drainage 

channels. Vegetation, if present in these sites, is sparse and may include various species ranging from 

stunted shrub forms to scattered bunchgrasses (e.g., Indian ricegrass and needle-and-thread). 

3.6.2.12 Non-vegetated Cover Type―Water 

This non-vegetated cover type occupies approximately 2,129 acres or about 0.2 percent of the project area 

(Table 3.6-1). 

3.6.2.13 Non-vegetated Cover Type―Rock or Talus Slope 

This non-vegetated cover type occupies approximately 1,034 acres or about 0.1 percent of the project area 

(Table 3.6-1), and includes naturally occurring areas of bare rock such as canyon cliffs, spires, rock 

outcrops, and talus fields. 

3.6.2.14 Non-vegetated Cover Type―Playa 

Playas occupy approximately 124 acres in the project area (Table 3.6-1). Playas are characterized as 

water catchments that are most often ephemeral, drain internally, accumulate sediment, and serve as 

recharge points to underground aquifers. While playas themselves are usually devoid of vegetation, they 

are commonly ringed by greasewood, shadscale, saltbush, and other salt-tolerant plants that provide 

critical winter forage for livestock and other herbivores. In Wyoming, playas, when flooded, are 

important sources of habitat for wildlife including waterfowl such as ducks and geese, along with sandhill 

cranes and shorebirds. Amphibians such as frogs, toads, and salamanders also depend on playas, as do 

several major orders of insects. 

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In most years playas are dry or water may only cover the lowest portion, the portion near a water source 

such as a spring, or the portion where an ephemeral stream discharges onto the playa surface. Between 

wet periods the surface of the playa typically dries out completely and may even become desiccated, 

forming polygonal cracks and fissures in clay-rich sediments. In playas where the groundwater table is at 

or near the surface, soluble salts will precipitate, forming ephemeral crusts that may or may not survive 

subsequent wetting episodes. The high salt and clay content of playa surface mud, and the dry and hot 

conditions that prevail most of the year, usually prevent plants from becoming established. 

3.6.3 Watershed-Based Land Health Assessment 

In 2008 the RFO finished conducting Standards and Guidelines Assessments for all the watersheds within 

the field office. These are watershed-based land health assessments mandated by the Director of the BLM 

on a 10-year basis. From 1998 through 2000, the RFO conducted Standards and Guidelines Assessments 

on an allotment basis; however, in 2001 to meet this 10-year timeframe, larger-scale watershed-based 

reports were undertaken. The Upper Colorado River and the Great Divide Basin were the first two 

watershed reports completed (2002 and 2003 respectively). Because these two watersheds were the first 

completed they are due for reassessment, at which time progress towards management objectives will be 

evaluated. Two of the standards apply to vegetation. Standard 2, Riparian and Wetland Vegetation, states 

that “riparian and wetland vegetation has structural, age, and species diversity characteristic of the stage 

of channel succession and is resilient and capable of recovering from natural and human disturbance in 

order to provide forage and cover, capture sediment, dissipate energy, and provide for groundwater 

recharge.” Standard 2 is considered to be met if riparian/wetland habitat is rated in Proper Functioning 

Condition (PFC) and existing management will lead to maintaining and/or improving resource conditions 

(BLM 2002). 

Standard 3, Upland Vegetation, states that “vegetation on each ecological site consists of plant 

communities appropriate to the site which are resilient, diverse, and able to recover from natural and 

human disturbance.” Standard 3 is considered to be met if plant communities are sustaining themselves 

under existing conditions and management. 

During the 2001 field season, project area watersheds within the Upper Colorado River Basin were 

assessed (BLM 2002). Results of the 2001 assessment indicated that Standard 2 – Riparian/Wetland 

Health, was being met by most allotments within the assessment area with the exception of 14 allotments, 

two of which are located in the project area (Cherokee 00408 & Red Creek 10521). 

Most of the lentic and lotic sites that are not meeting the standard have been, or are in the process of 

being, addressed in management plans or as range improvement projects (BLM 2002). Assessment results 

for Standard 3 – Upland Vegetation Health, indicated that natural and ecological processes were 

functioning adequately for most vegetation communities. However, the review team had concerns about 

the uniformity of age classes in many shrub stands which may lead to over-maturity/decadence on a large 

scale if not properly managed. Shrub communities in this late-seral stage are particularly susceptible to 

large-scale die-offs due to many environmental and biological factors including drought, insect 

infestations, and disease. 

3.6.4 Fugitive Dust Effects on Vegetation 

The Environmental Protection Agency (EPA) states that the largest single source of fugitive dust in the 

U.S. is from unpaved roads which contribute about 10 million tons of particulate matter (PM) air 

pollution each year (EPA 1998). Dust from roads can contain very fine particles known as PM10 

(particulate matter less than 10 microns in diameter) and PM2.5 (particulate matter less than 2.5 microns in 

size). Ten microns equals about 1/7th the diameter of a human hair. Of greatest concern are the PM2.5 

particles that make up part of a dust cloud. Although PM and other air-quality issues are described more 

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CHAPTER 3—AFFECTED ENVIRONMENT—VEGETATION
 

completely in Section 3.5 Air Quality, a brief discussion of the negative effects of fugitive dust on 

roadside/rangeland vegetation is presented in this section. 

Dust deposits on plants can have important effects on plant life. These effects may include (but are not 

limited to): 

 Reduced photosynthesis due to reduced light penetration through the leaf surface. This may cause 

stunting and/or reduced growth rates and plant vigor. 

 Increased incidence of plant pests and disease. Dust deposits can act as a medium for the growth of 

fungal diseases. 

 Reduced efficacy of herbicide sprays due to reduced penetration of the herbicide through the leaf 

surface. 

 Reduced productivity and changes in community structure (the species of plants present) (Farmer 

1993). 

 Increased leaf temperatures and water loss, with decreasing carbon dioxide uptake (Eller 1977, 

Hirano et al. 1995, Ricks and Williams 1974, Fluckinger et al. 1979, Thompson et al. 1984). 

 Decreased palatability and avoidance by wildlife and livestock. 

 Increased tooth wear for herbivores. 

	 Greater biomass of annual plants within the dust-plume-affected area. Phenological differences (see 

Glossary) among the vascular plants are possibly due to differences in soil temperature on and off 

the dust-plume area early in the growing season (Spencer and Tinnin 1997). 

	 Susceptibility of vegetation in proximity to roads to chronic diseases affiliated with photosynthesis 

and growth, which may eventually lead to accelerated erosion problems from lack of adequate 

roadside vegetation, reduction in quality and quantity of available browse for livestock and wildlife, 

and creation of new sites for noxious weed infestations (Gebbhart and Hale 1996). 

	 Potential contamination of native wildflowers and their blossoms, altering patterns of pollen 

dispersal (and thus gene flow) among plants by altering the foraging behavior of pollinating insects. 

This impact could be important in habitats in proximity to unpaved roads occupied by USFWS or 

BLM special status plant species of concern. 

GIS analysis of the road system within the project area indicates a total of about 5,736 miles of roads 

within the project’s boundaries. This total includes: about 126 miles of paved roads (mainly I-80 and WY 

789), about 2,055 miles of improved maintained exotic (e.g. graveled/rocked) roads, about 86 miles of 

improved maintained natural (e.g., natural surface) roads, and about 3,469 miles of unimproved, 

unmaintained natural (e.g., two-track) roads. These totals indicate that the total mileage of paved roads 

within the project area represents only about 2.2 percent of the total road system. Section 3.16 

Transportation and Access describes the local and regional transportation network associated with the 

project area. 

The primary factors that generate dust on unpaved roads include (Bolander 1999, Addo and Sanders 

1993): 

 Vehicle speed  Particle size distribution (gradation) of the 

 Number of wheels per vehicle surface material 

 Number of vehicles  Restraint of the surface fines (compaction, 

 Vehicle weight cohesiveness/bonding)
 

	 Durability of the road surface 

A 1993 U.S. Department of Transportation study cites a 1983 Forest Service estimate that for every 

vehicle traveling one mile of unpaved roadway once a day, every day for a year, one ton of dust is 

deposited along a corridor extending 500 feet on either side of the roadway (Addo and Sanders 1993). In 

a study conducted in Australia, McCrea (1984) estimated the potential losses in crop productivity for 

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CHAPTER 3—AFFECTED ENVIRONMENT—VEGETATION
 

various rates of dust deposition. The main focus of the report was on horticultural crops grown alongside 

unpaved roads, and in this case the losses occurred within about 656 feet of the source. 

To estimate the acreage of the project area that could be affected by road-generated fugitive dust, a GISgenerated mileage total for all improved exotic and improved natural surface roads within the project area 

was calculated and then buffered on each side of the road centerline by 578 feet to equal the average total 

width from the above two mentioned studies (1,156 feet). The two-track road mileage was not included in 

the calculations because of their minimal use. The results indicate that approximately 260,483 acres could 

be affected by road-generated fugitive dust deposition, or about 24.3 percent of the project’s total landsurface area. This total, at any given time, would be dependent upon season of use, the primary factors 

listed in this section, and weather-related factors, especially the timing and amount of precipitation events 

(or lack thereof). A proactive and aggressive road-watering/dust-suppression program could noticeably 

lower this estimate during the hotter and drier summer months that are generally associated with greater 

dust-generation potential. 

3.6.5 Biological Soil Crusts 

Biological soil crusts (BSCs), also referred to as cryptogamic, microbiotic, cryptobiotic, and microphytic 

crusts, are a complex assemblage of organisms including cyanobacteria, green algae, mosses, lichens, 

microfungi, and other bacteria that colonize the first few millimeters of the soil surface. Soil crusts are 

found in all hot, cool, and cold arid and semi-arid regions and may constitute up to 70 percent of the 

living cover in some plant communities (Belnap 1994). The functions of BSCs in rangeland ecosystems 

include retention of soil moisture by serving as a living mulch on the soil surface; reduction of wind and 

water erosion; fixing atmospheric nitrogen; and contributing to soil organic matter (Eldridge and Greene 

1994). 

The primary environmental factors that influence the distribution of biological soil crusts include 

elevation, precipitation volume, timing of precipitation, physical and chemical properties of the soil, 

topography, and disturbance regimes (Belnap 2001). The historic and current distribution of BSCs in the 

project area is largely unknown. However, field work conducted by HWA during May and June of 2007 

found soil crusts at several locations within the project area, with moss crusts the most frequently 

encountered. Moss crusts were found growing within cacti aggregations or underneath shrub canopies, 

and less frequently in the open plant interspaces. Moss crusts were also observed in several plant 

communities including those dominated by Wyoming big sagebrush, mountain big sagebrush, saltbush, 

and greasewood. Cyanobacterial crusts were observed in portions of the project area where the soils were 

less stable (e.g., sandy areas) or the crusts were re-establishing after disturbance. Lichen crusts were 

observed less frequently than moss or cyanobacterial crusts. The Creston grazing exclosure within the 

project area was observed to have a well-established lichen crust, including: Aspicilia, Caloplaca, 

Collema, Xanthoparmelia, and Psora. The most common moss was Tortula. Crustal development was 

greatest underneath shrub canopies or on the edges of bunchgrasses and less so in the plant interspaces. 

The assemblage of species present at this Wyoming big sagebrush site indicates a late-successional stage 

of crust development. This provides evidence that mature and diverse soil crusts have the potential to 

occur within the project area, given suitable environmental conditions. 

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CHAPTER 3—AFFECTED ENVIRONMENT—INVASIVE, NON-NATIVE PLANT SPECIES 

3.7 INVASIVE, NON-NATIVE PLANT SPECIES 

Generally, the term “weed” can be used for any unwanted plant. Terms such as aliens, exotics, and 

invasives are used interchangeably to describe specific weeds. All these descriptions have a common 

concept: plants introduced into an area in which they did not evolve that have the potential to cause 

noticeable economic and/or ecological impacts. When weeds become so widespread that they threaten 

crops, livestock, or native species, they may become more than just a “weed.” They might then be termed 

“noxious weed,” “invasive species,” “exotic species,” “alien species,” or some similar term as set forth in 

law by each governing body or land-management agency. 

Invasive plant species pose a threat to the long-term productivity, diversity, and aesthetic values of lands 

within the RFO. Recent extended drought conditions in Wyoming, in conjunction with unprecedented 

energy development and other construction activities in western Wyoming, have favored the 

establishment and spread of invasive weed species.,This has occurred not only in disturbed habitats, but 

also in native rangeland where the stress of drought has resulted in decreased vigor, annual production, 

resilience, and competitive capabilities of native grassland and shrub communities, thus creating an ideal 

environment for invasion and establishment of aggressive and invasive weedy species. 

The principal invasive weeds known to occur in or near, or which have been treated within, the project 

area include (BLM 2002) Russian knapweed (Centaurea repens), houndstongue (Cynoglossum 

officinale), halogeton (Halogeton glomeratus), hoary cress (whitetop) (Cardaria draba and Cardaria 

pubescens), perennial pepperweed (giant whitetop) (Lepidium latifolium), spotted knapweed (Centaurea 

maculosa), common burdock (Arctium minus), and saltcedar (Tamarix spp.). The primary impact of these 

invasive species to the range resource is their ability to out-compete native species; in addition to their 

competitive nature, Russian knapweed, halogeton, and houndstongue are poisonous to wildlife and/or 

livestock. 

Many of these invasive species are associated with disturbed areas such as road/pipeline rights-of-way 

and well pads. Other common invasive weed species observed in the project area include cheatgrass 

(Bromus tectorum), Russian thistle (Salsosa kali), netseed lambsquarter (Chenopodium berlandieri), bull 

thistle (Cirsium vulgare), black henbane (Hyoscyamus niger), common mullein (Verbascum thapsus), 

clasping pepperweed (Lepidium perfoliatum), kochia (Kochia scoparia), as well as several wild mustards. 

Of the invasive plant species found in the project area, halogeton represents an ecological and economic 

threat to the area due to its unparalleled rapid infestation and widespread establishment. Prior to the onset 

of extended drought conditions in Wyoming beginning in 2000, halogeton was present at low densities in 

southwest and south-central Wyoming but its presence was primarily restricted to range sites degraded 

over time by heavy livestock concentrations such as near feed-grounds, corrals, and travel-ways or 

disturbed sites such as the reclaimed Santa Fe Browning gravel pit near Wild Horse Butte (Bennett 2004). 

Extensive invasive weed surveys conducted by HWA during the 2007 growing season indicated that 

approximately 13,353 acres, or about 1.2 percent of the surface area of the project area, were infested 

with halogeton. This is a conservative estimate based upon surveys at specific sites such as well pads and 

road/pipeline rights-of-way (HWA 2008b). 

Although not quantified, the actual surface area infested by halogeton could be greater based on field 

observations that halogeton spreads laterally from infested road/pipeline rights-of-way into adjoining 

native rangeland. Observations made during the 2007 growing season, especially along the major 

north/south-oriented roads (e.g., Wamsutter Road) indicated that the lateral spread of halogeton was 

usually minimal (+ 15–20 feet) on the windward (west) side of the road but could extend as far as 0.25 

mile on the leeward side (east) of the road right-of-way. The direction of the prevailing winds during 

October and November when the plants are in the seed-drop stage is probably the dominant variable that 

controls dispersal direction. Halogeton seed is extremely light and fluffy and easily transported by even a 

slight breeze. If the same criteria are used as with fugitive dust impacts (Section 4.7.3.1), it is evident that 

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CHAPTER 3—AFFECTED ENVIRONMENT—WILDLIFE
 

as many as 260,000 total acres of disturbed and native rangeland in the project area may be at risk of 

infestation with halogeton. 

3.8 WILDLIFE 

3.8.1 Terrestrial Wildlife 

Information concerning current and historical wildlife observations and distribution within and near the 

CD-C project area were obtained from a variety of sources including BLM, USFWS, Wyoming Game 

and Fish Department (WGFD), Wyoming Natural Diversity Database (WYNDD), and information 

compiled from personal communications and unpublished data from BLM, WGFD, and USFWS 

biologists. The WGFD Wildlife Observation System (WOS) and WYNDD are the primary repositories 

for wildlife information in the state of Wyoming and contain records of wildlife observations for birds, 

mammals, herptiles (amphibians and reptiles), fish, and species of special concern. Wildlife information 

for the project area was supplemented with survey data collected by Hayden-Wing Associates, LLC 

(HWA) during 2006–2007 as part of the baseline and monitoring data requirements for the EIS. 

At least 396 wildlife species occur in and around the project area including: 77 mammal, 273 bird, six 

amphibian, 10 reptile, and 30 fish species (Appendix H). All wildlife species are important members of a 

functioning ecosystem and wildlife community, but most are common and have wide distributions in the 

region. Consequently, the relationships of most of these species to the proposed project are not discussed 

in the same depth as species that are Threatened, Endangered, rare, of special concern, of special 

economic interest, or otherwise of high interest or unique value. 

3.8.1.1 Wildlife Habitat 

A wide variety of wildlife habitats and associated species occur in the project area. Wildlife habitats that 

would be affected by the project include the areas that would be physically disturbed by the construction 

of gas wells, related roads, pipelines, and production facilities, as well as zones of influence surrounding 

them. Zones of influence are defined as those areas surrounding or associated with project activities 

where impacts to a given species or its habitat could occur. The shape and extent of such zones varies 

with species and circumstances. 

The project area is located in the Wyoming Basin Omernik Level III Ecoregion (18) and includes portions 

of the Rolling Sagebrush Steppe (18a) and Salt Desert Shrub Basins (18e) Level IV Ecoregions 

(Chapman et al. 2004). Topography in the project area is characterized by rolling plains interrupted by 

hills and strike-dip ridges dissected by alluvial and outwash fans that empty into broad, level basins. 

Ridges, hills, and rolling plains support vast areas of mixed-grass prairie and Wyoming, mountain, and 

basin big sagebrush communities. Active and stabilized sand dunes, as well as disjunct playas and 

alkaline flats, are interspersed throughout the project area where existing conditions are favorable for their 

formation. Vegetation communities in the poorly drained, alkaline basins are dominated by arid-land 

shrubs like greasewood, shadscale, and Gardner’s saltbush. Riparian and wetland habitats are scarce and 

found only at a few locations in the project area. Freshwater wetlands in the northern portion of the 

project area occur along Riner Road (BLM 3203) in the Chain Lakes area, and along Luman Road (i.e., 

SCR 20) north of Horseshoe Bend where a flowing well supplies year-round water to an enclosed water 

impoundment surrounded by emergent vegetation. A few large water impoundments along Muddy Creek 

create a series of connected semi-permanent wetlands in moist years in the southeastern portion of the 

project area. Detailed descriptions of vegetation community types within the project area are discussed in 

Section 3.6 Vegetation. 

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CHAPTER 3—AFFECTED ENVIRONMENT—WILDLIFE
 

3.8.1.2 Big Game 

Big game are included in the discussion due to their high interest and economic values. Three big game 

species occur in the project area, including pronghorn (Antilocapra americana), mule deer (Odocoileus 

hemionus), and elk (Cervus elaphus). Big game populations are managed by the WGFD within areas 

designated as Herd Units. Hunt Areas are the geographic boundaries within which hunting licenses are 

valid. Herd size and viability of big game populations are dependent on the combination, availability, and 

quality of seasonal ranges, which overlap among species and fulfill different requirements for resident 

and migratory big game populations. Table 3.8-1 shows Herd Unit population sizes and parameters 

within the project area from WGFD Job Completion Reports. Herd population objectives are set by 

WGFD each year based on a variety of factors including, but not limited to, the carrying capacity of the 

habitat, weather (e.g. drought), habitat fragmentation, and competition with other ungulates. 

Extreme drought occurred in the Green River Basin from 2000–2004, lessened in 2005, and then returned 

again in 2006 and 2007. Higher-than-normal snowfall during the winter of 2007–2008 increased winter 

mortality above normal. The winters of 2008–2009 and 2009–2010 were mild and drier than normal and 

winter mortalities were few. The springs of 2009 and 2010 saw above-average precipitation and 

seasonable temperatures resulting in above-average forage production. 

Table 3.8-1. Big game Herd Unit population parameters within the CD-C project area 

Species 

Herd Unit 

(number) 

Herd Unit 

total 

acreage 

Percent 

within 

project 

area 

Acreage 

within 

project 

area 

Population 

Trend 

2001-2009 

Population 

Estimate 

2009 

WGFD 

Population 

Objective 

Fawn:Doe 

Ratio 2009 

Pronghorn Baggs 

(438) 890,200 9.2 81,530 Slight increase 6,849 9,000 61:100 

Bitter Creek 

(414) 183,6992 23.3 428,104 Slight decrease 8,594 25,000 36:100 

Red Desert 

(615) 2,167,952 25.9 560,439 Slight decrease 14,355 15,000 60:100 

Mule Deer Baggs 

(427) 2,142,656 23.8 509,650 Slight increase 19,845 18,700 64:100 

Steamboat 

(430) 2,567,106 13.4 343,863 Increasing 4,600 4,000 47:100 

Chain 

Lakes (650) 699,626 30.9 216,560 Increasing 475 500 Not 

available 

Elk Sierra 

Madre 

(425) 

363,651 22.7 82,511 Slight 

increase 8,957 4,200 37:100 

Steamboat 

(426) 2,533,733 13.6 343,765 

Decreasing 

to meet 

objective 

1,500 1,200 54:100 

Petition 

(430) 1,838,167 23.3 427,496 Stable Not available 300 Not available 

Shamrock 

(643) 699,477 30.9 216,301 

Decreasing 

to meet 

objective 

130 75 Not 

available 

Source: WGFD 2011b 

Pronghorn are the most abundant big game within the project area. The project area includes portions of 

five Hunt Areas (53, 55, 57, 60, and 61) and three Herd Units (Table 3.8-1; Map 3.8-1). All three Herd 

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CHAPTER 3—AFFECTED ENVIRONMENT—WILDLIFE
 

Units are much larger than the portion within the project area, with 26 percent of the Red Desert Herd 

Unit, 23 percent of the Bitter Creek Herd Unit, and 9 percent of the Baggs Herd Unit acreages contained 

within the project area. Herd numbers can be affected by several factors including weather events 

(drought and severe winters), the impacts of excess population numbers (over acceptable management 

levels) upon habitat, hunting quotas, and disease. Meeting population objectives can depend upon the 

availability of human resources, the accuracy of wildlife information collected, weather variables, disease, 

and hunter harvest rates. Average hunter success in the pronghorn Hunt Areas in the CD-C project area is 

92 percent, resulting in a prorated annual harvest of approximately 640 animals (WGFD 2009 data). Refer 

to Section 3.12 Recreation for a more detailed discussion. Pronghorn seasonal ranges within the project 

area include spring/summer/fall (3.3 percent), winter/yearlong (88.3 percent), and crucial winter/yearlong 

(8.4 percent) (Table 3.8-2; Map 3.8-2). Although over a dozen pronghorn migratory movements have 

been documented within the project area, the corridors are broad and poorly defined (Map 3.8-2). 

Table 3.8-2. Big game seasonal ranges (acres) within the project area 

Species 

S E A S O N A L R A N G E 1 

CW CW/Y W W/Y Y S/S/F OUT UND 

Pronghorn -- 90,310 -- 944,678 -- 35,085 -- --

Mule Deer 3,973 13,876 -- 491,800 89,039 -- 471,385 --

Elk -- -- 26,894 -- 64,797 -- 550,343 428,039 

1	 Seasonal ranges include: Crucial Winter (CW) and Crucial Winter/Year-long (CW/Y) and describe ranges that have been 

identified as a determining factor in a population’s ability to maintain itself at a specified level (theoretically at or above the 

population objective) over the long term. Not all habitats within designated crucial winter range are of equal quality. Areas with 

higher quantity and quality of forage and areas that provide cover from extreme winter weather conditions provide the bestquality crucial winter range habitat. Crucial ranges are typically used 8 out of 10 winters; Winter (W) are used by a substantial 

number of animals during winter months (December through April; WGFD 2011b); Winter/Year-long (W/Y) ranges are occupied 

throughout the year but during winter they are used by additional animals that migrate from other seasonal ranges; Year-long (Y) 

ranges are occupied throughout the year but additional animals do not migrate to this type of seasonal range during winter; 

Spring/Summer/Fall (S/S/F) ranges are used before and after winter conditions persist; Non-use areas (OUT) contain habitats of 

limited or no importance to the species; Undetermined use areas (UND) are areas or habitats which are expected to or do 

support a population or portion of a population of animals, but for which the distribution and importance of the area has not been 

sufficiently documented to designate a seasonal range. 

Only 16 percent of the CWR for the Red Desert, Bitter Creek, and Baggs Herd Units occurs within the 

project area. In the springs of 2007, 2008 and 2010, a pronghorn CWR habitat assessment was conducted 

to attempt to define current conditions and identify factors that may be limiting the pronghorn population 

within the project area. CWR has long been established, and is accepted, as the most limiting factor for 

overall pronghorn populations within the state of Wyoming. However, several other factors can affect 

population trends including severe drought, winter severity, hunter harvest, or the impacts of excess 

individuals (over acceptable management levels) on habitat. For this assessment, the focus was placed on 

the identified CWRs within the project area which also serve as yearlong habitat for pronghorn. 

Therefore, an assessment was performed to determine the relative condition of the CWRs as both winter 

and yearlong range. In coordination with the WGFD, seven locations were identified to conduct the 

condition-class studies. Standard 100-foot line-intercept transects were used to gather vegetation quality 

and quantity data. The Extensive Browse method was used to gather utilization, age-class, and form-class 

information, and density board measurements were used to gather vertical cover and vegetation height 

estimates. The above data were then analyzed by two separate methods. The first method employed a 

Habitat Suitability Index model developed in Wyoming specifically for analysis of pronghorn winter 

ranges (Allen et al. 1984). The second is a BLM-accepted method for analysis of yearlong pronghorn 

range (BLM 1980). The results from these utilization analyses establish a baseline for future year-to-year 

comparisons and trends at these sample points (Table 3.8-3). 

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CHAPTER 3—AFFECTED ENVIRONMENT—WILDLIFE
 

Map 3.8-1. Pronghorn Herd Units in and around the CD-C project area 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

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Map 3.8-2. Pronghorn seasonal ranges and migratory movements in and around the CD-C project area 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

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CHAPTER 3—AFFECTED ENVIRONMENT—WILDLIFE
 

Table 3.8-3. Pronghorn Crucial Winter Range condition assessment results, 2007, 2008, and 2010 

Study site 

 (Map 3.8-2) Year Crucial Winter Range Rating1 Crucial Winter Range Score 1, 

PH-1 

2007 

2008 

2010 

Fair 

Fair 

Fair 

45 

33 

33 

PH-2 

2007 

2008 

2010 

Fair 

Fair 

NA 

32 

26 

0 

PH-3 

2007 

2008 

2010 

Fair 

Fair 

Poor 

30 

26 

20 

PH-4 

2007 

2008 

2010 

Fair 

Fair 

Fair 

43 

45 

43 

PH-5 

2007 

2008 

2010 

Fair 

Fair 

Fair 

30 

33 

43 

PH-6 

2007 

2008 

2010 

Poor 

Poor 

Fair 

24 

24 

31 

PH-7 

2007 

2008 

2010 

Poor 

Fair 

Fair 

19 

26 

28 

1

 CWR score is the calculated WFCI (Winter food/cover index)Wyoming pronghorn winter range habitat suitability index, Allen et 

al. (1984). 2

 Fair, poor, and good are all relative ratings as defined by the BLM based on the numerical outcome of the condition assessment. 

Generally, current conditions of pronghorn CWR are rated as “fair,” reflecting the moderate use of mature 

stands of Wyoming and mountain big sagebrush. In addition, CWRs north of I-80 are experiencing 

slightly less use than the CWRs along WY 789. 

Mule Deer are common year-round residents within the project area. The project area supports resident 

and migratory mule deer populations, and includes portions of five Hunt Areas (82, 84, 98, 100, and 131) 

and three Herd Units (Table 3.8-1, Map 3.8-3). Average hunter success in the five mule deer Hunt Areas 

in the CD-C project area is 45 percent, resulting in a prorated annual harvest of approximately 2,100 

animals (WGFD 2009 data). Refer to Section 3.12 Recreation for a more detailed discussion. At least a 

dozen mule deer migratory movements have been documented in the southern portion of the project area 

(Map 3.8-4). In addition, a telemetry study has revealed migratory movements through the southeastern 

portion of the project area (Sawyer 2007). 

Assessments conducted in 2001 determined that mule deer CWR located along and near the far 

southeastern edge of the project area was not meeting Standard #4 – Wildlife Habitat Health (BLM 2002; 

Map 3.8-4). Juniper and sagebrush dominance, declining shrub communities, over-browsing of favored 

shrub species, and low forb composition were some of the habitat concerns cited (BLM 2002). Although 

this site may not be meeting the standard, broader areas within the landscape may be ecologically 

functional. Changes in management may be necessary to address making progress toward meeting this 

standard in the future. 

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Map 3.8-3. Mule Deer Herd Units in and around the CD-C project area 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

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CHAPTER 3—AFFECTED ENVIRONMENT—WILDLIFE
 

Map 3.8-4. Mule deer seasonal ranges and migratory movements in and around the CD-C project area 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

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CHAPTER 3—AFFECTED ENVIRONMENT—WILDLIFE
 

Only 6.3 percent of CWR acreage for the Baggs Herd Unit occurs within the project area. Mule deer 

CWR habitat assessments were conducted concurrent with pronghorn CWR habitat assessments 

conducted in 2007, 2008, and 2010. As with pronghorn, mule deer CWR is the most limiting factor for 

populations within the state of Wyoming. In coordination with the WGFD, two locations were identified 

to conduct the condition-class studies. The Extensive Browse and density board methods were also 

employed to collect data on mule deer CWR sites. The data were then analyzed according to BLMaccepted methods for analysis of mule deer winter range (BLM 1979). The results from these utilization 

analyses establish a baseline for future year-to-year comparisons and trends at these sample points (Table 

3.8-4). 

Table 3.8-4. Mule deer Crucial Winter Range condition assessment results, 2007, 2008, and 2010 

Study site 

(Map 3.8-4) Year Crucial Winter Range 

Rating1 Crucial Winter Range 

Score1, 2 

2007 Fair 54.39 

MD-1 2008 Poor 42.63 

2010 Fair 54.39 

2007 Good 64.68 

MD-2 2008 Good 61.74 

2010 Good 63.21 

1

 Fair, poor, and good are all relative ratings as defined by the BLM based on the numerical outcome of the condition assessment. 

2

 Mule deer CWR score and rating calculated by BLM (2008). 

Data are available for only two sites and may indicate that variable forage conditions likely exist across 

the analysis area. Current forage conditions in mule deer CWR associated with the project area were 

similar to those of pronghorn; however, heavier use was evident at mule deer sites. At least a dozen mule 

deer migratory movements have been documented in the southern portion of the project area (Map 3.8-4). 

In addition, a telemetry study has revealed migratory movements through the southeastern portion of the 

project area (Sawyer 2007). As discussed above, animal movement along known migratory routes in the 

southeastern portion of the project area are compromised by WY 789, energy development, and numerous 

rangeland and highway fences (Feeney et al. 2004, WGFD 2010). Mule deer use of the underpasses 

constructed under WY 789 has been well documented using remote cameras (WYDOT 2012). The range 

condition data provided in Table 3.8-4 is indicative of the forage condition within migration routes. 

Although current conditions of mule deer CWR associated with the project area were similar to those of 

pronghorn, heavier use was evident at mule deer sites. Nevertheless, results indicated that mule deer 

CWR sites have mature stands of big sagebrush with adequate canopy cover and overall production. 

Elk are locally common in certain areas within the project area. The project area includes portions of five 

Hunt Areas (21, 100, 108, 118, and 124) and four Herd Units (Table 3.8-1, Map 3.8-5). Average hunter 

success in the five elk hunt areas in the CD-C project area is 47 percent, resulting in a prorated annual 

harvest of approximately 1,440 animals (WGFD 2009 data). Refer to Section 3.12 Recreation for a more 

detailed discussion. Elk seasonal ranges located within the project area include yearlong (6.1 percent), 

winter (2.5 percent), non-use (51.4 percent), and undetermined use areas (40.0 percent; Table 3.8-2, Map 

3.8-6). No elk CWR has been designated or elk migration routes documented within the project area (Map 

3.8-6). Therefore no elk CWR site-sampling was conducted. Although no elk migration routes have been 

mapped in the project area, they may be present. Elk do migrate from the Sierra Madre mountain range to 

winter range along the Atlantic and Red Rims east of the project area (Map 3.8-6), and elk have been 

documented using the Baggs/WY 789 underpasses (WYDOT 2012) 

Big Game Summary 

The project area is used by pronghorn, mule deer, and elk, although the areas and season of use vary by 

species. CWR (i.e., crucial winter and crucial winter/yearlong ranges) of pronghorn and mule deer 

3-92 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
 

CHAPTER 3—AFFECTED ENVIRONMENT—WILDLIFE
 

collectively comprise approximately 92,842 acres (8.7 percent) of the project area (Map 3.8-7). The 

Rawlins RMP (BLM 2008a) states that habitat quality will be functionally maintained within areas of 

overlapping big game CWR. Overlapping pronghorn and mule deer CWRs comprise 15,314 acres (1.4 

percent) of the project area (Map 3.8-7). 

The project area also hosts wild horses, which over time may result in direct (competitive displacement) 

and indirect (resource-sharing) competition with pronghorn, mule deer, and elk (see Section 3.10 Wild 

Horses). Wild horse populations may impact ungulate habitat over an extended period of time. 

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Map 3.8-5. Elk Herd Units in and around the CD-C project area 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

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CHAPTER 3—AFFECTED ENVIRONMENT—WILDLIFE
 

Map 3.8-6. Elk seasonal ranges and migratory movements in and around the CD-C project area 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

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Map 3.8-7. Big game Crucial Winter Ranges in the CD-C project area 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

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CHAPTER 3—AFFECTED ENVIRONMENT—WILDLIFE
 

3.8.1.3 Upland Game Birds 

Greater sage-grouse (Centrocercus urophasianus), Columbian sharp-tailed grouse (Tympanuchus 

phasianellus columbianus), and mourning doves (Zenaida macroura) occur within the project area 

(WGFD 2004a). Suitable habitat for chukar (Alectoris chukar), gray partridge (Perdix perdix), ringnecked pheasant (Phasianus colchicus), blue grouse (Dendragapus obscurus), ruffed grouse (Bonasa 

umbellus), and wild turkey (Meleagris gallopavo) does not exist within the project area, although these 

species are present in surrounding areas (WGFD 2004a). Upland game birds are managed by the WGFD 

within upland game management areas. The project area includes parts of three Upland Game 

Management Areas (UGMAs): Red Desert UGMA 9; Bitter Creek UGMA 10; and Sierra Madre UGMA 

25. Greater sage-grouse is a Candidate species for listing under the ESA and Columbian sharp-tailed 

grouse is designated as a sensitive species by the BLM. These species are discussed in Section 3.9 

Special Status Species. 

Mourning doves occupy a wide variety of habitats. Within the project area, mourning doves occur in 

sagebrush-grassland, mountain shrub, and riparian vegetation communities. Mourning doves breed within 

and migrate through the project area (WGFD 2004a). Based on recent records, mourning doves harvested 

within the project area account for a very small percentage of the state total (WGFD 2005b). 

3.8.1.4 Raptors 

Twenty-six raptor species are known to occur in or around the project area, including 14 that breed or 

potentially breed, two that over-winter, and ten that have been recorded as transients or migrants (Table 

3.8-5). Five species are designated as sensitive by the BLM and are discussed in detail in Section 3.9 

Special Status Species. 

A variety of raptor breeding, hunting, and winter habitats occur within the project area. Grasslands, 

shrublands, trees and shrubs in riparian areas, and cliffs, low bluffs, rocky outcrops, and badland breaks 

all provide suitable nest substrates throughout the project area. Muddy Creek and drainages that support 

trees and other riparian vegetation provide habitat for tree-nesting species and provide potential roosting 

sites for wintering raptors. Agency and contract wildlife biologists have located at least 938 raptor nests 

belonging to at least 11 species in or within one mile of the project area (BLM 2007a; Table 3.8-5; Map 

3.8-8). The raptor species utilizing 79 of these nest sites are unknown. 

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CHAPTER 3—AFFECTED ENVIRONMENT—WILDLIFE 

Table 3.8-5. Occurrence potential and documented nest sites of raptor and vulture species within the 

CD-C project area 

Common Name1 Scientific Name Occurrence 

Potential2 Documented Nest 

Sites 

American kestrel Falco sparverius B 18 

Bald eagle* Haliaeetus leucocephalus t --

Barn owl Tyto alba t --

Broad-winged hawk Buteo platypterus t --

Burrowing owl* Athene cunicularia B 31 

Cooper’s hawk Accipiter cooperii B 4 

Ferruginous hawk* Buteo regalis B 577 

Golden eagle Aquila chrysaetos B 108 

Great horned owl Bubo virginianus B 15 

Gyrfalcon Falco rusticolus t --

Long-eared owl Asio otus B 1 

Merlin Falco columbarius W --

Northern goshawk* Accipiter gentilis t --

Northern harrier Circus cyaneus B 9 

Northern pygmy owl Glaucidium gnoma t --

Northern saw-whet owl Aegolius acadicus t --

Osprey Pandion haliaetus t --

Peregrine falcon* Falco peregrinus t --

Prairie falcon Falco mexicanus B 34 

Red-tailed hawk Buteo jamaicensis B 48 

Rough-legged hawk Buteo lagopus W --

Sharp-shinned hawk Accipiter striatus pB --

Short-eared owl Asio flammeus pB --

Snowy owl Bubo scandiacus t --

Swainson’s hawk Buteo swainsoni B 14 

Turkey vulture Cathartes aura pB --

1 Special-status species indicated by asterisk

2

 Occurrence potential of raptor species includes: known breeding (B); known to be present during breeding season and 

potentially breed (pB); known to over-winter (W); and known transient or migrant (t) 

It is possible that some of the older documented raptor nests may have deteriorated beyond being suitable 

for raptor nesting and the nest sites are no longer available or used by breeding raptors. Nevertheless, nest 

sites with nests in suitable condition have the potential to be active in any given year. Moreover, each 

year new nests are built. All raptors and their nests are protected from take or disturbance under the 

Migratory Bird Treaty Act (16 USC, §703 et seq.) and Wyoming [Revised] Statute (WRS 23-1-101 and 

23-3-108). Golden and bald eagles also are afforded additional protection under the Bald and Golden 

Eagle Protection Act, amended in 1973 (16 USC, §669 et seq.). 

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CHAPTER 3—AFFECTED ENVIRONMENT—WILDLIFE
 

Map 3.8-8. Raptor nest site locations in or within one mile of the CD-C project area 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

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CHAPTER 3—AFFECTED ENVIRONMENT—SPECIAL STATUS SPECIES
 

3.8.1.5 Neotropical Songbirds 

Many species of neotropical songbirds utilize the project area for breeding, feeding, migration, and as 

year-round habitats (Appendix H, Occurrence Potential of Wildlife in the CD-C Project Area). All 

habitats throughout the project area are used to some degree by these species, but especially sagebrushgrassland, mountain shrub, and riparian vegetation communities. The Migratory Bird Treaty Act (16 

USC, §703 et seq.) protects 836 migratory bird species (to date) and their eggs, feathers, and nests from 

disturbances. Several migratory raptors and songbird species are also listed as BLM Sensitive Species 

(Section 3.9.2). 

3.8.2 Fish 

Almost all of the CD-C project area drains into two basins: the Little Snake River Basin (a component of 

the Colorado River system) and the Great Divide Basin. A very small proportion of the far western part of 

the project area drains into Bitter Creek, also a component of the Colorado River system. The Little Snake 

River Basin is fed by Muddy Creek, which drains the southeastern portion of the project area. The 

majority of the northern part of the project lies within the Great Divide Basin. The Great Divide Basin is 

closed, with no eventual outflow to an ocean (Map 3.4-1). 

3.8.2.1 Fish Habitat 

Due to limited precipitation, the majority of drainages within the project area are ephemeral. Ephemeral 

water tables are always below the stream channel, only flowing in direct response to precipitation or 

snow-melt. Ephemeral waters only support very limited aquatic communities for short periods when 

surface flow is present, although some ephemeral streams in the project area may be used for spawning. 

The largest stream within the project area is Muddy Creek, a high-elevation, cold desert stream that is 

designated as class 2AB by the WDEQ, and supports game and non-game species. Muddy Creek exhibits 

perennial flow for the majority of its length, and in some years flows intermittently as a result of irrigation 

water removal south of the George Dew/Red Wash wetlands complex. In years with high runoff amounts, 

Muddy Creek flows perennially throughout its length. Streamflow varies with location along the drainage. 

About 286 reservoirs and ponds (<1–960 acres) are present within the project area (Section 3.4.2.1). 

Some of the ponds and reservoirs that currently exist within the project area are fed by waters recovered 

from wells drilled at upstream locations, while others are impoundments on small drainages. These manmade impoundments are generally designed to supply water for livestock and wildlife use. Only one of 

these, Little Robbers Gulch Reservoir, is stocked annually with Colorado River cutthroat trout 

(Oncorhynchus clarki pleuriticus) by the WGFD. None of the others are known to sustain fisheries. 

3.8.2.2 General Fish 

About 30 species of fish may occur in the project area or in streams upstream or downstream of the 

project area (Table 3.8-6), including ten game-fish species and 20 non-game fish species. This 

information is based upon species potentially found in the Great Divide and Little Snake River Basins, 

plus four Threatened and Endangered species present downstream in the Colorado River System. About 

14 of the 30 species, including six native species, are likely to be present within the project area. Four of 

the 30 species are Threatened or Endangered (Section 3.9.1.3) and four are BLM Sensitive Species 

(Section 3.9.2.3). 

No fish have been collected from any streams within the Great Divide Basin. Consequently, all of the fish 

present within streams in the project area are found within the Muddy Creek watershed. Some 

impoundments in the Great Divide Basin portion of the project have been stocked with fish in the past, 

but none are known to sustain fisheries at the present. 

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CHAPTER 3—AFFECTED ENVIRONMENT—SPECIAL STATUS SPECIES 

Table 3.8-6. Fish species observed within, or that may potentially occur immediately upstream or 

downstream of, the CD-C project area 

Common Name Scientific Name Game or 

Non-game Basin1 

Present 

in project 

area 

Native WYNDD FOW BLM MCBMP WSAM WGFD Beatty 

2005 

Black bullhead Ameiurus melas Non-game LSR x 

Bluehead sucker Catostomus 

discobolus Non-game LSR Yes Yes X X X X X 

Bonytail Gila elegans Non-game CR Yes 

Brook trout Salvelinus fontinalis Game LSR, GDB Yes X X X X 

Brown trout Salmo trutta Game LSR X 

Channel catfish Ictalurus punctatus Game LSR X 

Colorado 

pikeminnow Ptychocheilus lucius Non-game LSR, CR Yes X X 

Colorado River 

cutthroat trout 

Oncorhynchus clarki 

pleuriticus Game LSR X X X X X 

Common carp Cyprinus carpio Game LSR, GDB X X 

Creek chub Semotitus 

atromaculatus Non-game LSR Yes X X X X X 

Fathead Minnow Pimephales promelas Non-game LSR Yes X X 

Flannelmouth 

sucker Catostomus latipinnis Non-game LSR Yes Yes X X X X X 

Humpback chub Gila cypha Non-game CR Yes 

Iowa darter Etheostoma exile Non-game LSR X X X X 

Longnose dace Rhinichthys cataractae Non-game LSR Yes X X X 

Longnose sucker Catostomus 

catostomus Non-game LSR X 

Mottled sculpin Cottus bairdi Non-game LSR Yes Yes X X X X 

Mountain sucker Catostomus 

platyrhynchus Non-game LSR Yes Yes X X X X 

Mountain whitefish Prosopium williamsoni Game LSR Yes X X X 

Northern Pike Esox lucius Game LSR X 

Rainbow trout Oncorhynchus mykiss Game LSR, GDB Yes X X X 

Razorback sucker Xyrauchen texanus Non-game CR Yes 

Red Shiner Cyprinella lutrensis Non-game LSR X 

Redside shiner Richardsonius 

balteatus Non-game LSR Yes X X X X X 

Roundtail chub Gila robusta Non-game LSR Yes Yes X X X X X 

Sand Shiner Notropis stramineus Non-game LSR Yes X 

Speckled dace Rhinichthys osculus Non-game LSR Yes Yes X X X X 

Walleye Stizostedion vitreum Game LSR X X 

White sucker Catostomus 

commersoni Non-game LSR Yes X X X 

1 Basins LSR = Little Snake River Basin 

 GDB = Great Divide Basin

 CR = These species are downstream residents of the Colorado River system. 

Data Sources: 

- Wyoming Natural Diversity Database (WNDD 2003) 

- Fishes of Wyoming (FOW) (Baxter and Stone 1995) 

- Muddy Creek Basin Management Plan (MCBMP)(WGFD 1998) 

- M. Fowden, pers.comm. 2004 

- Bureau of Land Management (BLM) (BLM 2001) 

- Warmwater Stream Assessment Manual (WSAM) (WGFD 2004) 

- BLM 2001 

- Beatty 2005 

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CHAPTER 3—AFFECTED ENVIRONMENT—SPECIAL STATUS SPECIES
 

3.9 SPECIAL STATUS SPECIES 

Special-status species include: (1) Threatened, Endangered, Proposed, Candidate, or those petitioned for 

listing as Threatened or Endangered by the USFWS under the Endangered Species Act (ESA) of 1973, as 

amended; and (2) those designated by the BLM State Director as sensitive (BLM 2010). 

3.9.1 Threatened, Endangered, Proposed, or Candidate Species of Wildlife, Fish, and 

Plants 

Seven species listed by the USFWS as Threatened, Endangered, Proposed, or Candidate pursuant to the 

ESA, that may be found in the RFO are or potentially are present within the project area (USFWS 2010, 

Table 3.9-1). Four fish species are found downstream of the RFO in the Colorado River system and may 

be impacted if water depletions occur, or if environmental contaminants are increased within the system. 

The other four species—Canada lynx, yellow-billed cuckoo, Wyoming toad, and the blowout 

penstemon—are located within the RFO; however, they are not located nor do they have habitat within or 

near the CD-C project area. 

Table 3.9-1. Occurrence potential of Threatened, Endangered, Proposed, and Candidate species within 

or near the CD-C project area 

Species1 Scientific Name Occurrence Potential 

within the project area2 Status3 

Mammals 

Black-footed ferret Mustela nigripes U Endangered 

Birds 

Greater sage-grouse Centrocercus urophasianus P Candidate 

Amphibians 

Fish 

Bonytail* Gila elegans PAD Endangered 

Colorado pikeminnow* Ptychocheilus lucius PAD Endangered 

Humpback chub* Gila cypha PAD Endangered 

Razorback sucker* Xyrauchen texanus PAD Endangered 

Plants 

Ute ladies’-tresses Spiranthes diluvialis pp Threatened 

1

 Presence in the Colorado River system downstream of the project area is indicated by asterisk. 2

 Occurrence potential includes: present (P); potentially present (pp); unlikely (U); very unlikely (VU); and potentially affected 

downstream (PAD).
 3

 Candidate species are those for which the USFWS has sufficient information to propose for listing as threatened or endangered 

under the ESA, but for which development of a proposed listing regulation is precluded by other higher priority listing actions. 

Proposed species are those Candidate species that were found to warrant listing as either threatened or endangered and are 

currently undergoing a 12-month status review. Conservation measures for candidate and proposed species are voluntary but 

recommended because, by definition, the species may warrant future protection under the ESA if adequate conservation 

measures are not in place. 

3.9.1.1 Threatened or Endangered Wildlife Species 

Black-footed ferret. This species is considered the most endangered mammal in the United States. The 

original distribution of the black-footed ferret in North America closely corresponded to that of the prairie 

dog (Cynomys spp.; Hall and Kelson 1959, Fagerstone 1987). Black-footed ferrets depend almost 

exclusively on prairie dogs for food and also use prairie-dog burrows for shelter, parturition, and raising 

young (Hillman and Clark 1980, Fagerstone 1987). The species historically ranged throughout most of 

the sagebrush and grasslands habitats in Wyoming. Today, the only known population of black-footed 

ferrets in Wyoming is the result of the reintroduction of captive-bred ferrets in the Shirley Basin ( 

approximately 65 miles northeast of the project area). Reintroductions occurred in Wyoming on federal 

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CHAPTER 3—AFFECTED ENVIRONMENT—SPECIAL STATUS SPECIES
 

and state lands from 1991 to 1995. The reintroduced population is classified as nonessential experimental, 

and currently is self-sustaining. 

The USFWS has designated some areas of Wyoming as not likely to have black-footed ferret habitat 

present; these areas have been “Block Cleared” and do not require ferret surveys prior to activities being 

permitted. “Non-Block Cleared areas” may contain suitable black-footed ferret habitat. Forty-five percent 

of the project area is within portions of the Continental Divide, Desolation Flats, and Dad Non-Block 

Clearance areas, which were not included under the black-footed ferret block clearance letter (Map 3.9-1; 

USFWS 2004b). Prairie-dog colonies occurring within the Continental Divide, Desolation Flats, and Dad 

non-block clearance areas meet requirements for consideration as black-footed ferret habitat (Biggins et 

al. 1989), and black-footed ferret surveys may be necessary prior to ground-disturbing activities (Biggins 

et al. 1989, USFWS 1989). Mapping and ground surveys indicate that the area and density of active 

prairie-dog colonies within the project area may be sufficient to support black-footed ferrets. The RFO, in 

coordination with the USFWS, has refined and mapped the white-tailed prairie dog complex areas that 

would require pre-disturbance surveys (Map 3.9-1, BLM M. Read, pers. com. 2012). 

Numerous historical records of black-footed ferrets have been documented within the project area 

(WYNDD 2007, WGFD 2007). Within the Continental Divide/Wamsutter II project area, two young 

black-footed ferrets were sighted in 1972 about five miles south of I-80; one adult was sighted in August 

1975 in the northern portion; and a black-footed ferret skull was found in 1981 along the northeastern 

border. Wild-born black-footed ferrets currently exist in the Shirley Basin; at least 88 ferrets were 

observed during a partial survey conducted in 2004 (WGFD 2005b). Various barriers exist between the 

Shirley Basin black-footed ferret population and the project area, including highways (i.e., U.S. 287, I80), mountain ranges (i.e., Freezeout, Shirley, and Seminoe), reservoirs (i.e., Pathfinder and Seminoe), 

and the North Platte River. 

Greater sage-grouse is a sagebrush obligate found entirely in the western United States and Canada, 

primarily in the Intermountain West. Wyoming contains more sage-grouse than all other states combined. 

The species remains common in Wyoming because its habitat is relatively intact compared to other states. 

In south-central Wyoming, the harsh climate has limited habitat loss and conversion to settlements and 

agriculture. Historically, disturbance to greater sage-grouse habitat in south-central Wyoming has 

occurred as a result of livestock grazing, associated sagebrush-control treatments, and oil and gas 

development. Landscape-scale disturbance to this habitat has resulted more recently from the increased 

development of a variety of energy resources and the associated workforce. The greater sage-grouse is 

considered a sagebrush ecosystem umbrella species, which assumes that conserving its habitat will benefit 

other species of conservation concern that share the same habitats (i.e., pygmy rabbit, sage thrasher, and 

sage sparrow; Rowland et al. 2006). 

Sage-grouse depend on extensive areas of sagebrush for food and cover throughout the year. Typically, 

strutting grounds or leks are located in open patches within sagebrush habitat and the surrounding area is 

considered potential nesting habitat. Nesting habitat tends to have higher sagebrush density, taller live and 

residual grasses, more live and residual grass cover, and little bare ground (Connelly et al. 2004). Sagegrouse are dependent upon sagebrush habitats for their year-round survival. This dependency includes 

using sagebrush for forage, nesting habitat, brood-rearing habitat, and winter thermal cover. In addition, 

sage-grouse require a variety of sagebrush habitat types to meet life-history requirements. Mesic habitats 

are also important for brood-rearing during the summer and fall months. The proximity of nesting habitat 

to brood-rearing habitat increases its value for broods, but may increase risk for nests (Dzialak et al. 

2012). 

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Map 3.9-1. Black-footed ferret Non-Block Clearance areas and 2007 prairie-dog colony mapping area 

in and around the CD-C project area 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

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Sage-grouse exhibit site fidelity to leks, winter and summer areas, and nesting areas (Schroeder et al. 

1999). They may be affected by sagebrush community disturbance and removal. Sage-grouse tend to 

avoid areas that may provide perching or roosting opportunities for raptors (i.e., fence posts, power lines, 

and other structures) (Connelly et al. 2000 and 2004). Human activity during the breeding season may 

disrupt lek attendance and affect local breeding success. Populations across the west have declined from 

historic levels due to a wide range of factors including drought, habitat loss, and habitat degradation 

(Connelly and Braun 1997, Braun 1998, Connelly et al,. 2000 and 2004). 

In 2004, the USFWS conducted a status review of greater sage-grouse throughout their range in response 

to petitions requesting the listing of the species under the ESA. On January 7, 2005, the USFWS 

determined that the greater sage-grouse did not warrant protection under the ESA. Nevertheless, on 

December 4, 2007, U.S. District Court Judge B. Lynn Winmill reversed the USFWS decision and 

remanded the case to the agency for further consideration. After another status review, the USFWS 

concluded in 2010 that the greater sage-grouse warranted protection under the ESA; however, ESA 

protection was precluded due to other species facing more immediate extinction threats (a warranted but 

precluded decision). As a result, the greater sage-grouse was added to the list of Candidate species under 

the ESA, which provides a status review every 12 months to determine if immediate attention is 

warranted. 

Although greater sage-grouse is currently a Candidate species, it receives no statutory protection under 

the ESA. However, certain conservation measures and stipulations are enforced by the BLM in 

accordance with BLM Sensitive Species management and by state agencies under the Statewide 

Executive Directive #2011-5 (SWED 2011, WGFD 2011c), Greater Sage-grouse Core Area Protection 

(SGEO) program. The SGEO enhanced habitat protection in sage-grouse core population areas on public 

as well as on private lands, when the activities on private land are subject to review or approval by state 

or federal statutes. In December 2011, BLM issued Instruction Memorandum (IM) 2012-043 (BLM 

2012b) which provides rangewide interim management policies and procedures for conserving sagegrouse and their habitats. This IM reaffirms the application of the Wyoming Core Population Area 

Protection process, as follows: 

“The BLM field offices do not need to apply the conservation policies and procedures described in 

this IM in areas in which (1) a state and/or local regulatory mechanism has been developed for the 

conservation of the Greater Sage-Grouse in coordination and concurrence with the USFWS 

(including the Statewide Executive Directive 2011-5, Greater Sage-Grouse Core Area Protection); 

and (2) the state sage-grouse plan has subsequently been adopted by the BLM through the issuance 

of a state-level BLM IM.” 

On February 10, 2012, the BLM released IM WY-2012-019, Greater Sage-Grouse Habitat Management 

Policy on Wyoming BLM Administered Public Lands Including the Federal Mineral Estate. This 

document provides guidance to BLM Wyoming field offices regarding management consideration of 

greater sage-grouse habitats for proposed activities until resource management planning updates are 

completed (BLM 2012c). The IM is consistent with IM WY-2012-043 (BLM 2012b) and is generally 

consistent with the SGEO (SWED 2011, WGFD 2011c). The conservation strategy for greater sagegrouse in the State of Wyoming continues to evolve. The Wyoming BLM is currently amending the Field 

Office RMPs regarding sage-grouse management and the requirements that would be applied to activities 

in sage-grouse habitat will change in accordance with those RMP amendments. 

As required by IM WY-2012-019, an 11-mile analysis buffer is required around the project boundary for 

large-scale proposed actions (e.g. oil and gas full-field developments). According to the WGFD database, 

192 known leks are located within 11 miles of the CD-C project area; 105 are occupied, 13 are 

unoccupied, and 74 have undetermined status (Map 3.9-2, WGFD 2010c). Leks are assigned an annual 

status of active, inactive, or unknown, and based on this leks are assigned a management status of 

occupied, unoccupied (destroyed or abandoned), or undetermined. Within 11 miles of the CD-C project 

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area, there are approximately 546,600 acres of state-designated core population areas on BLM-managed 

land and 244,890 acres on state or private lands. 

Prohibition of surface occupancy will be considered and evaluated by the BLM (2012c) and SGEO 

(SWED 2011) within 0.25 miles of non-core area leks and 0.6 miles of core area leks, measured from the 

perimeter of occupied or undetermined leks. Quarter-mile buffers around the perimeter of occupied or 

undetermined status leks located in non-core areas within the project area comprise approximately 3,072 

acres (0.29 percent of the project area), which includes 1,215 acres of BLM, 0.17 acres of state, and 1,858 

acres of private lands. The 0.6-mile buffers around the perimeter of occupied or undetermined status leks 

located in core areas within the project area compromise approximately 4,185 acres (0.3 percent of the 

project area), which includes 2,167 acres of BLM, zero acres of state, and 2,018 acres of private lands. 

BLM WY IM 2012-019 provides the following management actions for greater sage-grouse (BLM 

2012c) and allows for local variation in the timing stipulation applicability dates. 

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Map 3.9-2. Greater sage-grouse potential nesting/brood-rearing habitat, leks, core areas, and 11-mile 

CD-C project area buffer 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

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The Rawlins RMP timing stipulation dates are reflected below: 

	 In core population areas, surface-disturbing and disruptive activities will be prohibited in all nesting 

and early brood-rearing habitat, regardless of the distance from the nearest lek (Map 3.9-2) from 

March 1 to July 15 (BLM 2012, BLM 2008a). 

	 In non-core areas, surface-disturbing and disruptive activities will be prohibited within all identified 

nesting and brood-rearing habitat (Map 3.9-2) from March 1 to July 15 (BLM 2012, BLM 2008a). 

	 Surface-disturbing and/or disruptive activities are prohibited or restricted from November 15 – 

March 14 in mapped or modeled winter habitats/concentration areas (BLM 2012, BLM 2008a). 

	 Additional greater sage-grouse conservation measures that may be applied by the BLM can be 

found in the IM WY-2012-019 (BLM 2012c) and the Rawlins RMP. 

BLM and other partners are working to develop statewide seasonal habitat models to identify important 

sage-grouse seasonal habitats. Until such time as those models are complete, and in the event there is a 

question that suitable nesting and early brood-rearing habitats exist in a particular area, the IM WY-2012­

019 states that seasonal habitats will be determined using appropriate methods found in the Habitat 

Assessment Framework, or HAF. The Rawlins RMP (BLM 2008a, p. 2-55) states that surface-disturbing 

and/or disruptive activities are to be avoided in all identified nesting and early brood-rearing habitat (Map 

3.9-2) from March 1 to July 15. The RFO also applies this level of protection to nesting and early broodrearing habitat in non-core areas (M. Read, pers. com., February 2012). Currently, RFO wildlife 

biologists have defined “identified nesting and brood-rearing habitat” as any mesic shrub-dominated 

vegetative community (R. M. Etzelmiller, pers. com., May 2011). Map 3.9.3 provides an overview of 

areas where seasonal nesting and early brood-rearing restrictions would be applied unless site-specific 

field work indicates that nesting and early brood-rearing habitat is not actually present at a particular 

location. 

Surface-disturbing and disruptive activities are defined in the Wyoming BLM Guidance for Use of 

Standardized Surface Use Definitions (WY Information Bulletin 2007-029). For sage-grouse, disruptive 

activity typically includes people and/or the activity in nesting habitats for a duration of one hour or more 

during a 24-hour period during the nesting season (BLM IM WO-2010-071 2010). 

Greater sage-grouse populations are hunted in some areas of Wyoming, including the project area; the 

harvest from the South Central Conservation Area, which contains the project area (Upland Game 

Management Areas 9, 10, 24, 25, and 45), comprised 10.2 percent of the statewide yield in 2010 (Table 

3.9-2; WGFD 2011). Since 1995, sage-grouse harvest numbers have been reduced by earlier opening 

dates, shorter hunting season length, and lower bag limits. 

Table 3.9-2. Greater sage-grouse harvest numbers for the South Central Conservation Area 

Year Harvest (South Central) Statewide Harvest Percent of Statewide Harvest 

1998 1,681 16,720 10.1 

1999 1,931 21,407 9.0 

2000 3,106 20,347 15.3 

2001 1,641 12,577 13.0 

2002 1,021 4,557 22.4 

2003 664 4,835 13.7 

2004 1,472 11,783 12.5 

2005 2,519 13,178 19.1 

2006 1,342 12,920 10.4 

2007 1,163 10,378 12.1 

2008 1,773 10,303 17.2 

2009 1,619 11,162 14.5 

2010 1,126 11,057 10.2 

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A sage-grouse population trend analysis (Figure 3.9-1) was conducted to compare sage-grouse 

populations associated with the CD-C project area to other related sage-grouse populations in 

southwestern Wyoming and the state as a whole. Specifically, the populations compared include (1) CDC plus 11-mile analysis area, (2) the Core Population Areas affected by the CD-C project (Greater South 

Pass), (3) the statewide population, and (4) the “count” leks in the CD-C project area. The WGFD sagegrouse database (WGFD 2010) was used for this analysis. A count lek is a lek, designated by WGFD, on 

which the count lek protocol is performed annually. The count lek protocol is a survey method that is 

designed to give greater assurance that the actual peak male attendance is observed for that lek. There are 

five count leks related to CD-C; three are located in the east-central project area, one is in the northeast 

corner of the project area, and one is in the southeast corner. Average peak male attendance is used as an 

index of overall population size because the information is the most readily available and comprehensive. 

It has been suggested that a ratio of two hens per male in attendance could be used to determine the 

overall population size of grouse in an area. However, there have been a number of studies that call this 

ratio into question. Since it is not currently known what conversion factor should be used in the project 

area to achieve an accurate total population size, no attempt was made to do so here. 

The year 1990 was chosen as a beginning point of the comparison analysis to demonstrate the cyclical 

nature of the species. Also during this period, throughout the state, sage-grouse survey and count 

protocols were improved and more consistently applied. As demonstrated in Figure 3.9-1, the population 

trend in all study groups is similar regardless of the size of the population involved. This comparison of 

four different groups of sage-grouse leks removes the question of local weather conditions affecting the 

population or the level of survey effort or of any one sub-set of leks affecting or controlling the overall 

trend. 

0

10

20

30

40

50

60

70

1990

919293949596979899

2000

123456789

2010

Average Peak Male Lek Attendance

Year 

CD-C Project Area Lek Comparisons 

Statewide Greater South Pass Core Area 

CD-C Area + 11 mi buffer CD-C Count Leks 

Figure 3.9-1. Average peak observed male attendance for leks associated with the project 

area (WGFD 2011) 

As can be seen in Figure 3.9-1, all populations analyzed experienced similar increases and decreases in 

numbers of individuals observed. It is generally agreed (Connelly 2004) that sage-grouse populations are 

cyclical; Figure 3.9-1 indicates an apparent seven-year cycle. 

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3.9.1.2 Threatened or Endangered Fish Species 

Four federally Endangered fish species may occur as downstream residents of the Colorado River System: 

Colorado pikeminnow (Ptychocheilus lucius), bonytail (Gila elegans), humpback chub (Gila cypha), and 

razorback sucker (Xyrauchen texanus) (USFWS 2004a). The Colorado pikeminnow, bonytail, and 

humpback chub are all members of the minnow family. The razorback sucker is a member of the sucker 

family. All four of these fish species share similar habitat requirements and historically occupied the same 

river systems. Declines in populations of these species are mainly attributed to impacts of water 

development (e.g. dams and reservoirs) on natural temperature and flow regimes, creation of migration 

barriers, habitat fragmentation, the introduction of competitive and predatory non-native fishes, and the 

loss of inundated bottom lands and backwater areas (Minckley and Deacon 1991, USFWS 1993). 

The last sighting of any of these fish species in the Little Snake River was of a single Colorado 

pikeminnow in 1990. No critical habitat for these species has been designated in Wyoming (Upper 

Colorado River Endangered Fish Recovery Program 1999). However, the potential for project-related 

reductions in water quantity and/or quality to these tributaries to the Colorado River warrant their 

inclusion in this document. 

Bonytail. Habitat of the bonytail is primarily limited to narrow, deep, canyon-bound rivers with swift 

currents and whitewater areas (Valdez and Clemmer 1982, Archer et al. 1985, Upper Colorado River 

Endangered Fish Recovery Program 1999). With no known reproducing populations in the wild today, 

the bonytail is thought to be the rarest of the Endangered fishes in the Colorado River System. 

The bonytail historically inhabited portions of the upper and lower Colorado River basins. Today in the 

upper Colorado River Basin, only small, disjunct populations of bonytail are thought to exist in the 

Yampa River in Dinosaur National Monument, in the Green River at Desolation and Gray canyons, in the 

Colorado River at the Colorado/Utah border, and in Cataract Canyon (Upper Colorado River Endangered 

Fish Recovery Program 1999). 

Colorado pikeminnow. The Colorado pikeminnow is the largest member of the minnow family and 

occurs in swift, warm waters of the Colorado River basins. The species was once abundant in the 

mainstem of the Colorado River and most of its major tributaries throughout Wyoming, Colorado, Utah, 

New Mexico, Arizona, Nevada, California, and Mexico. It was known to occur historically in the Green 

River of Wyoming at least as far north as the City of Green River. In 1990, one adult was collected from 

the Little Snake River in Carbon County, Wyoming (Baxter and Stone 1995). Subsequent survey attempts 

to collect Colorado pikeminnow from this area of the Little Snake River by WGFD personnel failed to 

yield any other specimens. 

Humpback chub. Habitat of the humpback chub is also limited to narrow, deep, canyon-bound rivers 

with swift currents and whitewater areas (Valdez and Clemmer 1982, Archer et al. 1985, Upper Colorado 

River Endangered Fish Recovery Program 1999). 

The humpback chub was historically found throughout the Colorado River System and its tributaries, 

which are used for spawning (Valdez et al. 2000). It is estimated that the humpback chub currently 

occupies 68 percent of its original distribution in five independent populations that are thought to be 

stable (Valdez et al. 2000). 

Razorback sucker. The razorback sucker is an omnivorous bottom-feeder and is one of the largest fishes 

in the sucker family. Adult razorback sucker habitat use varies depending on season and location. This 

species was once widespread throughout most of the Colorado River Basin from Wyoming to Mexico. 

Today in the Colorado River Basin, populations of razorback suckers are only found in the upper Green 

River in Utah, the lower Yampa River in Colorado, and occasionally in the Colorado River near Grand 

Junction (Upper Colorado River Endangered Fish Recovery Program 1999). 

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3.9.1.3 Threatened, Endangered, Proposed, Candidate, or Experimental Plant Species 

The USFWS (2002) has determined that one threatened plant species, Ute ladies’-tresses, may 

potentially be present within the project area (Table 3.9-1). This species is not known to occur within the 

project area, but it may potentially be affected by the proposed project. The known locations of this 

species in Wyoming include Converse, Goshen, Laramie, and Niobrara Counties. This species is not 

known to occur within the project area and the likelihood of it occurring there is low for the following 

reasons: (1) much of the project area is very arid and there are few perennial streams; (2) the elevation of 

the project area is near the upper limit for the species; (3) very few moist riparian area meadows are 

present; (4) where present, the transition from stream margins to upland vegetation is abrupt; and (5) in 

Wyoming, the species has only been located in the eastern and southeastern portions of the state (Fertig 

2000). 

3.9.2 BLM Sensitive Species 

The BLM has developed a Sensitive Species List for public lands in Wyoming (Table 3.9-3). The list 

includes species that are not listed as Endangered or Threatened by the USFWS but may be rare or 

declining in the state.. The objective of the Sensitive Species designation is to ensure that the overall 

welfare of these species is considered when undertaking actions on public lands, and that these actions do 

not contribute to the need to list the species under the provisions of the ESA. It is the intent of this policy 

to emphasize the inventory, planning consideration, management implementation, monitoring, and 

information exchange for the sensitive species on the list. The BLM Sensitive Species List is meant to be 

dynamic and is reviewed annually with recommendations from BLM and appropriate non-BLM 

authorities for additions and deletions (BLM 2010). Twenty-eight species on the BLM Sensitive Species 

List that occur in the RFO may occur in or near the CD-C project area. 

Table 3.9-3.	 Occurrence potential and habitat associations of BLM Sensitive Species within or near the 

CD-C project area 

Common Name Scientific Name Occurrence 

Potential1 Habitat Association2 

Mammals 

Fringed myotis Myotis thysanodes pp Caves, forest, shrublands 

Long-eared myotis Myotis evotis U Caves, forest, shrublands 

Pygmy rabbit Brachylagus idahoensis P Sagebrush 

Spotted bat Euderma maculatum pp Cliffs, sagebrush 

Swift fox Vulpes velox pp Grasslands 

Townsend’s big-eared bat Corynorhinus townsendii pp Caves, forest, shrublands 

White-tailed prairie dog Cynomys leucurus P Sagebrush-grasslands 

Wyoming pocket gopher Thomomys clusius P Sagebrush-grasslands 

Birds 

Bald eagle Haliaeetus leucocephalus P Rivers, stream and lakes 

Brewer’s Sparrow Spizella breweri P Sagebrush 

Burrowing owl Athene cunicularia P Grasslands 

Ferruginous hawk Buteo regalis P Sagebrush-grasslands 

Loggerhead shrike Lanius ludovicianus P Shrublands 

Long-billed curlew Numenius americanus P Grasslands 

Mountain plover Charadrius montanus P Grasslands 

Peregrine falcon Falco peregrinus U Cliffs, rivers 

Sage sparrow Amphispiza belli P Sagebrush 

Sage thrasher Oreoscoptes montanus P Sagebrush 

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CHAPTER 3—AFFECTED ENVIRONMENT—SPECIAL STATUS SPECIES 

Table 3.9-3.	 Occurrence potential and habitat associations of BLM Sensitive Species within or near the 

CD-C project area, continued 

Common Name Scientific Name Occurrence 

Potential1 Habitat Association2 

Amphibians 

Great Basin spadefoot Spea intermontana P Sagebrush 

Northern leopard frog Rana pipiens pp Plains and foothills ponds 

Fish 

Roundtail chub Gila robusta P Rivers, stream and lakes 

Bluehead sucker Catostomus discobobulus P All waters 

Flannelmouth sucker Catostomus latipinnis P Rivers, stream and lakes 

Colorado River cutthroat trout Onchorhynchus clarki 

pleuriticus pp Mountain streams 

Plants 

Meadow milkvetch Astragalus diversifolius P 

Moist, salt-accumulating 

habitats such as alkaline 

meadows and playa shorelines 

Cedar Rim thistle Cirsium aridum pp 

Barren, chalky hills, gravelly 

slopes, and fine textured, 

sandy-shaley draws 

Gibben's beardtongue Penstemon gibbensii pp 

Barren south-facing slopes on 

loose sandy-clay derived from 

Brown's Park formation 

Persistent sepal yellowcress Rorippia calcycina P River banks and shorelines 

1

 Occurrence potential includes: present (P), potentially present (pp), unlikely (U), and very unlikely (VU);( WGFD 2004a; HWA, 

unpublished data). 2 WGFD 2004a. 

3.9.2.1 Sensitive Wildlife Species 

Twenty terrestrial species and four fish species designated by the BLM as Sensitive that occur in the RFO 

may occur in or near the CD-C project area and thus potentially could be affected by the Proposed Action 

(Table 3.9-3; BLM 2010, WGFD 2007, WYNDD 2007). The black-tailed prairie dog, Baird’s sparrow, 

Columbian sharp-tailed grouse, northern goshawk, trumpeter swan, white-faced ibis, hornyhead chub, and 

boreal toad are located within the RFO; however, they are not located nor do they have habitat within or 

near the CD-C project area. 

Mammals 

Fringed myotis. This bat species occupies a variety of coniferous forests, woodland chaparral, and basinprairie shrubland habitats throughout western North America from British Columbia to southern Mexico. 

In Wyoming, its residency status is currently unknown (WGFD 2004a). This species could potentially 

utilize the project area for feeding; roosting sites may occur in the project area as suitable habitat (i.e., 

caves and mines) is present. 

Long-eared myotis may hibernate in Wyoming, but the species is considered uncommon and its 

residency status currently is unknown (WGFD 2004a). Long-eared myotis has been documented 

approximately 15 miles west of the project area (WYNDD 2007). Suitable habitat for the species occurs 

in the project area. 

Pygmy rabbit. A sagebrush obligate, the pygmy rabbit requires tall sagebrush and deep, soft soil for 

burrowing. Therefore, it is not distributed uniformly across the sagebrush shrub-steppe ecosystem. The 

species occurs in eight western states (California, Idaho, Montana, Nevada, Oregon, Utah, Washington 

and Wyoming), and has been documented throughout western Wyoming including Carbon and 

Sweetwater counties. It should be noted that the Columbia Basin Distinct Population Segment in 

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Washington State is managed differently and is currently listed as Endangered under the ESA. In 

September 2010, the USFWS released its 12-month finding on a petition to list the pygmy rabbit as 

Endangered or Threatened range-wide under the ESA and found that listing was not warranted. Although 

listing was not warranted, the USFWS acknowledged several threats to pygmy rabbit habitat including 

sagebrush conversion for agricultural purposes, livestock grazing, and energy development. Suitable 

pygmy rabbit habitat is patchily distributed but abundant in the Continental Divide Basin and surrounding 

areas. Pygmy rabbits have been documented throughout the project area (WYNDD 2007, HWA 

unpublished data). 

Spotted bat. Although it occurs sporadically as a summer resident across the western United States, the 

spotted bat has not been documented in the project area (WGFD 2007, WYNDD 2007). Spotted bat is 

associated with juniper shrublands and desert-sagebrush grasslands in Wyoming (WGFD 2004a). The 

species may occur in the project area. Roosting habitat such as cliffs is present although perennial water is 

lacking. 

Swift fox. The swift fox inhabits short-grass and mixed-grass prairies over most of the Great Plains, 

including eastern Wyoming (Clark and Stromberg 1987). Studies have documented swift fox in Carbon 

and Sweetwater Counties within the project area and the species potentially may occur (Woolley et al. 

1995). However, no swift fox have been documented in Sweetwater County in recent years (WGFD 2007, 

WYNDD 2007). 

Townsend’s big-eared bat can be found throughout Wyoming and its distribution is likely determined 

by the availability of roosts such as caves, mines, tunnels, and crevices with suitable temperatures (Clark 

and Stromberg 1987). Although its residency status is currently unknown, it may hibernate in Wyoming 

in caves (WGFD 2004a). This species has not been observed within or near the project area (WGFD 

2007, WYNDD 2007). It may be present in the project area as forage and roosting habitat (caves, mines, 

rock outcrops, and buildings) are present. 

White-tailed prairie dog. This species occupies grassland, sagebrush, and arid shrubland habitats in 

central and western Wyoming (Clark and Stromberg 1987) and is found in scattered colonies throughout 

the project area. Approximately 8,818 acres of white-tailed prairie-dog colonies have been mapped within 

the project area to date (Map 3.9-3a and 3.9-3b; BLM RFO unpublished data; HWA unpublished data). 

Wyoming pocket gopher. Endemic to southeastern Sweetwater County and southwestern Carbon 

County, the Wyoming pocket gopher has been documented within the project area (WYNND 2007, HWA 

2008 and 2009). Another population has been recorded in Carbon County approximately 20 miles east of 

the project area near Bridger’s Pass, and the species may occur elsewhere (Clark and Stromberg 1987). In 

August 2007, the Wyoming pocket gopher was petitioned for listing under the ESA. The rationale for 

petitioning the species included a lack of knowledge regarding its taxonomy, abundance, population 

trends, distribution, habitat requirements, and the potential effects from energy development within their 

range. In April 2010, the USFWS determined the Wyoming pocket gopher did not warrant protection as a 

threatened or endangered species under the ESA. 

As part of the survey efforts for the 12-month status review, HWA biologists collaborated with the BLMRFO and WYNDD to conduct an extensive trapping effort during 2008 and 2009. The objective of the 

study was to capture Wyoming pocket gophers to genetically verify its status as a separate species, and to 

collect additional information on its distribution within the project area and across its predicted range in 

general. In 2008, 10 Wyoming pocket gophers and 20 northern pocket gophers were trapped in 351 trapnights within the project area. Capture locations were concentrated within 15 miles southwest of 

Wamsutter on the plateaus above Wamsutter and Delaney Rims (HWA 2008c ). In 2009, ten Wyoming 

pocket gophers and 12 northern pocket gophers were trapped in 550 trap nights within the project area. 

Capture locations were distributed throughout the project area, including eight captures approximately 20 

miles southwest of Creston Junction (I-80 and WY 789) and two captures 10 miles north of Creston 

Junction (HWA 2009). Wyoming and northern pocket gophers appear to be sympatric (have overlapping 

ranges) within the project area. 

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Map 3.9-3a. White-tailed prairie-dog colonies within the CD-C project area 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

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Map 3.9-3b. White-tailed prairie-dog colonies within the CD-C project area 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

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Birds 

Bald eagle. This large North American eagle is normally found near water. It is found throughout North 

America, but primarily breeds in Canada, Alaska, the Pacific Northwest, the Rocky Mountains, and the 

Great Lakes region. Bald eagles have been observed in the project area primarily from November through 

March (WGFD 2004a, HWA unpublished data). The species may forage within the project area during 

the winter months because of carrion associated with pronghorn, mule deer, and elk winter ranges (Maps 

3.8-2, 3.8-4, and 3.8-6). No bald eagle nests or nesting habitat (mature, large diameter trees near open 

water) occur within the project area. The nearest potential nesting habitat occurs along the Little Snake 

River approximately nine miles south of the project area. 

Brewer’s sparrow. A sagebrush obligate, Brewer’s sparrow breeds throughout the intermountain west of 

the United States and winters in southern portions of California, Arizona, New Mexico, and western 

Texas, and south through the central part of Mexico (Rotenberry et al. 1999, Sibley 2000). Brewer’s 

sparrows will breed in a variety of shrubland habitats, but prefer areas dominated by big sagebrush 

(Artemisia tridentata; Rotenberry et al. 1999). It prefers to nest in shrubs that are taller and denser than 

average (Petersen and Best 1985). This species may be particularly sensitive to habitat fragmentation, and 

appears to be affected more by changes at the landscape level than at the local level (Knick and 

Rotenberry 1995). Brewer’s sparrow is expected to breed and has been observed within the project area 

(WGFD 2004a, WYNDD 2007, HWA unpublished data). 

Burrowing owl. The burrowing owl is found throughout the plains and prairies of the western United 

States during the spring, summer, and fall (Haug et al. 1993). While the species has the capacity to 

excavate its own burrow, it seldom does, relying instead on mammals such as prairie dogs, ground 

squirrels, and badgers (Thomsen 1971). The burrowing owl’s close association with burrowing mammals 

suggests dependence on them (Haug et al. 1993). Knowles (1999) suggested that the burrowing owl is a 

near prairie-dog obligate species because its distribution is so closely tied to that of prairie dogs. 

Burrowing owls also use isolated ground-squirrel and badger burrows in hillsides, and road borrow 

ditches. 

Burrowing owl is listed as a species of special concern across Wyoming, as a consequence of long-term 

population declines (Haug et al. 1993). Because of the strong association between burrowing owls and 

prairie dogs, declines in the burrowing-owl population have been linked to many of the same factors 

associated with declining prairie-dog populations (i.e., rodent-eradication programs and habitat loss). 

Furthermore, long-term conservation of the burrowing owl will likely be closely linked to the 

conservation and preservation of prairie-dog complexes, and other burrowing mammals. Burrowing owl 

occurs and breeds within the project area (BLM 2007a, WGFD 2004a, WYNDD 2007, HWA 

unpublished data). 

Ferruginous hawk. Primarily found in mixed-grass prairie and sagebrush steppe habitats during the 

spring, summer, and fall, the ferruginous hawk generally builds nests on rock outcrops, the ground, or 

cliff ledges. Although a small population overwinters in Wyoming, most individuals migrate south for the 

winter. Ferruginous hawks are common in south-central Wyoming and breed within the project area 

(BLM 2007a, WGFD 2006, WYNDD 2007). The western two-thirds of Carbon County hosts one of the 

highest nesting densities of ferruginous hawks within Wyoming (BLM 2007a). BLM records document 

the occurrence of 577 ferruginous hawk nest sites (Table 3.8-5; BLM unpublished data) in or within one 

mile of the project area. 

Loggerhead shrike. This species breeds and winters throughout the United States in a wide variety of 

open habitats with some shrub or scattered-tree component. A summer resident, it usually builds its nest 

within large shrubs such as sagebrush, bitterbrush, or greasewood (Woods and Cade 1996). Loggerhead 

shrike populations have experienced declines across much of the species’ range primarily due to loss of 

habitat. Livestock grazing in combination with drought is a major factor in the decline. In addition, the 

loggerhead shrike is prone to the negative effects of pesticide use because its diet consists largely of 

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insects. The species is expected to breed and has been observed within the project area (WGFD 2006, 

WYNDD 2007, HWA unpublished data). 

Long-billed curlew. A locally common summer resident of Wyoming (WGFD 2004a), the long-billed 

curlew prefers gentle, rolling topography in native grasslands, sagebrush, and agricultural lands that can 

be arid as long as a water source is relatively nearby. One observation of a long-billed curlew has been 

documented in the extreme south of the project area (WGFD 2006). It is unlikely the species breeds in the 

project area because suitable breeding habitat and water are limited. 

Mountain plover. The mountain plover is dependent on short-grass prairie and also is frequently 

associated with prairie-dog towns (Knowles et al. 1982). The species nests on the ground in large 

grassland areas with short, sparse vegetation and substantial amounts of bare ground. In May 2011 the 

USFWS determined that the mountain plover is not threatened or endangered throughout all or a 

significant portion of its range. Numerous observations of mountain plovers have been recorded within 

the project area (WGFD 2007, BLM unpublished data, HWA unpublished data). Approximately 342,393 

acres of occupied or potential mountain plover habitat have been mapped, comprising approximately 32 

percent of the project area (Map 3.9-4; HWA unpublished data). 

Peregrine falcon. The peregrine falcon breeds throughout North America, including the Arctic, the 

Pacific coast, the Rocky Mountains, and scattered areas across the eastern United States. Although 

populations of avian prey species in and around the project area may be abundant and diverse enough to 

support the species, breeding is unlikely due to the lack of high cliffs suitable for nesting. Nevertheless, 

peregrine falcons may be present within the project area during migration. 

Sage sparrow. A sagebrush obligate found throughout much of the western United States, the sage 

sparrow breeds in sagebrush expanses from the northern edges of the Great Basin west of the Rocky 

Mountains to the chaparral and sagebrush scrub in Baja California (Martin and Carlson 1998). Suitable 

sagebrush habitat is widespread and abundant within the project area. The sage sparrow is expected to 

breed and has been observed within the project area (WGFD 2006, WYNDD 2007, HWA unpublished 

data). 

Sage thrasher. A sagebrush obligate found throughout the intermountain west, the sage thrasher builds 

nests in shrub-steppe communities dominated by sagebrush. Suitable sagebrush habitat is widespread and 

abundant within the project area. The sage thrasher is expected to breed and has been documented within 

the project area (WGFD 2007, WYNDD 2007, HWA unpublished data). 

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Map 3.9-4. Occupied and potential mountain plover habitat within the CD-C project area 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

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CHAPTER 3—AFFECTED ENVIRONMENT—SPECIAL STATUS SPECIES
 

Amphibians 

Great Basin spadefoot. An occupant of sagebrush and greasewood communities as well as playas below 

6,000 feet, the Great Basin spadefoot deposits eggs in springs or flooded areas formed by heavy rains 

(WGFD 2004a). Its life history requires suitable foraging areas, ephemeral breeding ponds, and 

overwintering sites. In the winter this species digs its own burrow and will overwinter underground, 

sometimes as deep as 15 feet. The Great Basin spadefoot has been documented in Sweetwater, Lincoln, 

Fremont, and Natrona Counties, and has been documented within the project area (Baxter and Stone 

1992, WGFD 2006, WYNDD 2007). Playas and riparian areas within the project area likely support this 

species. 

Northern leopard frog. This frog species is usually found close to wetlands, cattail marshes, and along 

vegetated shorelines during summer, but will venture several hundred meters along wet drainages during 

wet periods (Werner et al. 2004). A member of the true frog family (Ranidae), the northern leopard frog 

is an obligate of permanent water in the plains, foothills, and montane zones of Wyoming up to 9,000 feet 

above sea level (WGFD 2004a). This species has been documented within six miles of the project area 

and has a high probability of occurring in any area having perennial water (WYNDD 2007). The northern 

leopard frog was petitioned for listing under the ESA; in October 2011 the USFWS determined at listing 

was not warranted. 

3.9.2.2 Sensitive Fish Species 

Fish species that are not listed as Endangered or Threatened by the USFWS, but that may be rare or 

declining in the state, have been included on the BLM’s Wyoming Sensitive Species List (BLM 2002). 

The intent of the sensitive species status is to ensure that actions on BLM-administered lands consider the 

welfare of these species and do not contribute to the need to list any other species under the provisions of 

the Endangered Species Act (BLM 2001). 

Four BLM Wyoming State sensitive fish species are known to occur in portions of streams on or adjacent 

to the project area. These include the roundtail chub (Gila robusta), bluehead sucker (Catostomus 

discobolus), flannelmouth sucker (Catostomus latipinnis), and Colorado River cutthroat trout 

(Oncorhynchus clarki pleuriticus) (WYNDD 2003, BLM 2002). The three non-game fish species 

(roundtail chub, bluehead sucker, flannelmouth sucker) have been found within Muddy Creek 

downstream, within, and upstream of the project area, and in Bitter Creek downstream of the project area 

(WGFD 1998, 2004c, 2007a). In general, all three species are associated with hard substrates and deep 

pool habitat (Bower 2005). 

The Muddy Creek watershed is one of the few stream systems in Wyoming where these three native, nongame fish species exist together (WGFD 2004b) and the only watershed where these species and 

Colorado River cutthroat trout are known to coexist. It has also been designated as Aquatic Crucial 

Habitat by the WGFD because the area addresses Goal 1 of the WGFD Strategic Habitat Plan (WGFD 

2009). Because of the high conservation value of Muddy Creek for these species, multiple studies have 

been conducted to increase understanding of their ecology in the creek. The BLM is a signatory to the 

range-wide (Wyoming and other states) conservation agreement and strategy for roundtail chub, bluehead 

sucker, and flannelmouth sucker where these three non-game species are present. The BLM, WGFD, and 

University of Wyoming completed a study to better characterize the abundance, distribution, behavior, 

habitat requirements and genetics of the three non-game sensitive species within the Muddy Creek 

watershed, which included part of the project area (Beatty 2005). The following is a summary of those 

study results for 2004. 

Man-made structures have resulted in three fragmented stream segments in the lower Muddy Creek 

watershed (Beatty 2005, Map 3.9-5). The farthest downstream segment (segment 1) begins at the 

confluence of Muddy Creek with the Little Snake River and extends upstream to a wetland complex with 

water-control structures that inhibit fish movement. The farthest downstream segment experiences periods 

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of no surface flow with isolated pools and was dominated by non-native fishes in 2004. The middle 

segment (segment 2) consists of a wetland complex with numerous water-control structures and was 

dominated by non-native species, particularly the fathead minnow (Pimephales promelas). The upstream 

segment (segment 3) extended from upstream of the wetland complex to a headcut stabilization structure 

that prevents upstream movement by fish. The upstream segment was dominated by two native species: 

roundtail chub (Gila robusta) and speckled dace (Rhinichthys osculus). Constructed wetlands and barriers 

to upstream movements by fishes appear to influence native fishes and the structure of fish communities 

in lower Muddy Creek, similar to the effects of fragmentation and intermittent stream flows in other areas 

of the Colorado River Basin. 

Compton (2007) completed a study on the effects of barriers on these three sensitive species in Muddy 

Creek upstream of the wetland complex. Instream structures prevented or severely limited upstream 

movements, but downstream movements over structures occurred. Within each segment in this study 

area, roundtail chubs were most abundant and flannelmouth suckers were least abundant among the 

three native species. A core population of the three native species existed in one segment and 

supported the highest densities of juveniles and adults and the broadest length ranges. Non-native 

white suckers, Catostomus commersoni, were the most abundant species in the study area. Their 

highest densities occurred in altered habitat. Substantial hybridization with the two native catostomid 

species was evident. Compton (2007) concluded that native fish populations in the most upstream 

segment may be at risk of extirpation due to low abundance and reproduction. Connectivity among 

habitats is required to carry out the life-cycles of native fishes and fragmentation by man-made 

structures is affecting their abundance and distribution patterns. 

WGFD (2007a) sampled these three species in the Muddy Creek and Bitter Creek watersheds in 2006 

as part of a study of these species within the Green River watershed in Wyoming. Of the three 

species, only roundtail chubs were found in lower Muddy Creek. However, flannelmouth suckerwhite sucker hybrids were found there. In upper Muddy Creek within the CD-C project area, all three 

species were found as well as flannelmouth sucker-white sucker hybrids and blue sucker-white 

sucker hybrids. Flannelmouth suckers also were found in the headwaters of Bitter Creek. WGFD 

(2007a) concluded that perhaps the biggest threat to native bluehead and flannelmouth suckers in the 

Green River drainage of Wyoming is the occurrence of and subsequent hybridization with nonnative 

white sucker. 

The Colorado River cutthroat trout, which is a native game fish, has been re-introduced into Muddy Creek 

upstream of the project area and into Littlefield Creek, a tributary to Muddy Creek, upstream of the 

project area. Before the introduction was made, all fish in these segments of these creeks were eliminated 

and a fish barrier was installed on Muddy Creek immediately upstream of McKinney Creek to prevent 

non-native fish from gaining access to the stream. In addition to the Colorado River cutthroat trout, the 

WGFD is planning to re-introduce all native species into the segment of Muddy Creek upstream of the 

barrier. Colorado River cutthroat trout also occur downstream from the project area in the Little Snake 

River (Baxter and Stone 1995). This species had been petitioned for listing as Threatened or Endangered; 

however, the decision “not warranted to list” was made in June 2007. 

Besides Muddy Creek, all of the other streams on the project area are ephemeral and therefore do not 

have the potential to support BLM Wyoming State sensitive fish species on a year-round basis. Studies 

indicate that the non-game, native species may ascend ephemeral tributary streams to spawn (USFWS 

1985, Maddux and Kepner 1988, Weiss et al. 1998). Thus, ephemeral drainages fed by runoff from the 

project area may provide habitat for sensitive fish on a seasonal basis. 

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Map 3.9-5. Lower Muddy Creek Watershed 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

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Bluehead sucker. Present in the Little Snake, Green, Snake, and Bear River basins in Wyoming (Baxter 

and Stone 1995, WGFD 1998, WGFD 2004a), the bluehead sucker occupies habitats similar to that of the 

roundtail chub. This species is considered rare in Wyoming in comparison with other sucker species. This 

species occurs in the Little Snake River and is found in Muddy Creek upstream of and within the project 

area (Baxter and Stone 1995, WGFD 1998, WGFD 2004a, Bower 2005, Beatty 2005, Compton 2007, 

WGFD 2007a). It has hybridized with non-indigenous white suckers (Catostomus commersoni) in Muddy 

Creek (Compton 2007, WGFD 2007a). 

Colorado River cutthroat trout. This is the only trout native to the Green River and Little Snake River 

drainages in Wyoming (Baxter and Stone 1995). Historical records indicate it was present in Muddy 

Creek in the mid-1800s (Fowden, WGFD, personal communication). Historically, this subspecies 

inhabited clear-water tributaries of the Colorado River in Colorado, Utah, Wyoming, and probably also in 

New Mexico and Arizona (Behnke 1992). This species now occupies only a fraction of its former range. 

Some of the most genetically “pure” of the remaining populations of this trout subspecies are found in the 

Little Snake River upstream of the project area in Carbon County, Wyoming (Baxter and Stone 1995). 

Colorado River cutthroat trout have been re-introduced into Littlefield Creek and Muddy Creek upstream 

of the project area. Therefore, this species occasionally may occur within the project area, although 

suitable habitat is not present to sustain it. The species is generally associated with steep, clear, cold-water 

streams around rocky areas, riffles, deep pools, and near or under overhanging banks and logs (Binns 

1977). Colorado River cutthroat trout have been extirpated from much of their original range through 

competition with brook trout, rainbow trout, and brown trout, and hybridization with rainbow trout (Binns 

1977). 

Flannelmouth sucker. One of the most abundant and widely distributed sensitive fish species of the 

tributaries and mainstream portions of the Upper Colorado River Basin, the flannelmouth sucker is found 

primarily in the Yampa, Little Snake, Colorado, Green, and Gunnison River. It is also common in Muddy 

Creek in Carbon County, Wyoming, upstream of and within the project area (Bower 2005, Beatty 2005, 

Compton 2007, WGFD 2007a). There is limited information on the life history of this species. The 

available information suggests that flannelmouth suckers utilize habitats in medium to large rivers and are 

seldom found in smaller creeks, doing poorly in impoundments (Lee et al. 1980, Baxter and Stone 1995, 

and Colorado Water Resources Research Institute [CWRRI] 2000). Causes for their decline include 

construction of mainstream dams, altered river flows and water temperatures, and hybridization with the 

white sucker (Minckley 1973). The species has hybridized with white suckers in Muddy Creek (Compton 

2007, WGFD 2007a). 

Roundtail chub. The roundtail chub is a close relative of the federally Endangered humpback chub and 

bonytail. Its habitat consists of warm streams and larger rivers, usually in areas with slow-flowing water 

adjacent to areas of faster current (CWRRI 2000). This species is common within the Little Snake River 

drainage and is found in Muddy Creek upstream of and within the project area (Baxter and Stone 1995, 

WGFD 1998, WGFD 2004a, Bower 2005, Beatty 2005, Compton 2007, WGFD 2007a). 

3.9.2.3 Sensitive Plant Species 

Four BLM sensitive plant species may potentially occur within the project area. Two of the species are 

known to occur within the project area (BLM 2002b, Heidel 2008). The names and probability of 

occurrence of these species are listed in Table 3.9.1. The following species are located within the RFO; 

however, they are not located nor do they have habitat within or near the CDC project area: Laramie 

columbine, Trelease’s milkvetch, many-stemmed spider-flower, dune wild rye, limber pine, and Laramie 

false sagebrush. 

Gibben’s beardtongue. In Wyoming, the known occurrences of Gibben’s beardtongue are confined to 

extreme southwest Carbon County and extreme southeast Sweetwater County near the state line. This 

plant has been documented approximately 9 miles west of the southern tip of the project area (WYNDD 

2007) and it has the potential to likely occur within the project area. Gibben’s beardtongue may occur in 

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CHAPTER 3—AFFECTED ENVIRONMENT—SPECIAL STATUS SPECIES
 

grass-dominated sites with scattered shrubs, semi-barren fringed sagebrush/thickspike wheatgrass 

communities with 15–20 percent vegetation cover, or on ashy slopes amid Cercocarpus montanus. It may 

also occur on outcrops of the Green River Formation on steep yellowish sandstone-shale slopes below 

caprock edges. 

Cedar Rim Thistle is endemic to the Wind River and Green River basins of central Wyoming. This plant 

has the potential to occur in the project area; however, the species has not been found within the project 

area (WYNDD 2007). 

Persistent sepal yellowcress is generally found along moist, sandy stream banks, stock ponds, and manmade reservoirs near the high-water line. This species was located by HWA near Lost Creek below 

Eagles Nest Spring during special status plant surveys during the 2006 and 2007 growing seasons (HWA 

2008a). Results of the surveys indicate the occurrences of persistent sepal yellowcress are mainly 

associated with the Lost Creek drainage near the Eagles Nest Spring site in the northern portion of the 

project area. 

Meadow milkvetch is a perennial halophytic herb found in moist, salt-accumulating habitats. It is 

restricted to low topographic positions within the sagebrush zone of valleys and closed-basin drainages in 

alkaline meadows, playa shorelines, discharge zones, mounds, and shrub patches (Heidel 2008). The 

species has been documented in three extant occurrences in south-central Wyoming, totaling 

approximately 8,000 plants within about 187 acres, near the Chain Lakes region of the project area 

(Heidel 2009). 

3.10 WILD HORSES 

The Rawlins Field Office (RFO) maintains and manages wild horses (Equus caballus) in herd 

management areas (HMAs) and establishes an appropriate management level (AML) for each HMA. 

There are no wild burros within the project area and there will be no further discussion concerning wild 

burros in this EIS. The AML is the population objective for the HMA that will ensure an ecological 

balance for all users and resources of the HMA (e.g., wildlife, livestock, wild horses, vegetation, water, 

and soil). The current AMLs were established in 1994 from a process that included five years of focused 

and intensive monitoring, evaluation of data, public input, and environmental analysis (BLM 2005b). 

The RFO has the responsibility to protect, manage, and control wild horses in its resource area pursuant to 

the Wild Horse and Burro Act of 1971 (Public Law 92-195). The wild-horse program is responsible for 

monitoring both the land and the herds, removing excess animals, and preparing animals for adoption. 

The RFO manages three HMAs, two of which are partially located within the CD-C project area: the Lost 

Creek HMA and a small portion of the Adobe Town HMA (Map 3.10-1). The Lost Creek HMA 

encompasses approximately 251,000 acres, of which 235,000 are BLM-administered public lands. Of the 

BLM-administered total, approximately 119,600 acres of the HMA are located within the project area, 

virtually all of that acreage within the Cyclone Rim Grazing Allotment. The Lost Creek HMA is located 

within the closed Great Divide Basin with annual precipitation averaging a little less than six inches. With 

the exception of its northern border, all of the Lost Creek HMA surface area in the project area is located 

within the Cyclone Rim grazing allotment. 

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Map 3.10-1. Wild horse management areas within the CD-C project area in relation to major land cover 

types and affected grazing allotments 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

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The current AML for this HMA is approximately 60 to 82 horses which represents the high and low AML 

targets in relation to the gather-and-removal cycle. The current population estimate for the Lost Creek 

HMA is 120 adult animals (Mirati 2010). It was last gathered in the fall of 2009. The Lost Creek HMA is 

partially fenced from the checkerboard lands to the south. The Antelope Hills HMA adjoins the Lost 

Creek HMA to the north and is administered by the Lander Field Office. 

The Adobe Town HMA is located approximately 20 miles west of Baggs, within Carbon and Sweetwater 

counties. The HMA encompasses approximately 472,812 acres, of which 444,744 acres are BLMadministered public lands. Of the BLM-administered total, approximately 5,826 acres of the HMA—1.2 

percent of the total—are located within the CD-C project area (Map 3.10-1), including portions of the 

Continental, South Flat Top, Red Creek, and Willow Creek grazing allotments in the southwestern 

portion of the project area. Average annual precipitation in this area ranges from 7 inches in the desert 

basins to more than 12 inches at some of the higher locations. The current AML for this HMA is 

approximately 610 to 800 horses which represents the high and low AML targets in relation to the gatherand-removal cycle (BLM 2005b, updated June 2011). 

The Salt Wells Creek HMA, managed by the Rock Springs Field Office (RSFO), adjoins the Adobe 

Town HMA to the west and both share a common, unfenced border. Past capture, census, and distribution 

data collected by both the RFO and RSFO indicate considerable movement and interchange takes place 

among the horses of these two HMAs (BLM 2005b). Consequently, both the RSFO and RFO work 

cooperatively to manage the two HMAs in the most efficient manner. The most recent gather of the 

Adobe Town/Salt Creek Complex was conducted in the fall of 2010 resulting in 1,939 horses removed 

from the complex. It is estimated that approximately 860 adult horses remain in this complex (Mirati 

2010). In the majority of cases, wild horses have no natural enemies and population growth rates have 

been shown to be capable of 16- to 25-percent annual increases. This can result in a doubling of the wildhorse population every three to five years (BLM 2005b). However, in several instances, mountain lion 

(Felis concolor) predation has been documented to affect population growth rates (Turner and Morrison 

2001). In the southern Great Basin of Nevada, mountain lion predation on the young was believed to be a 

major population-limiting factor (Greger and Romney 1999) with the recruitment-rate reduction due to 

take of foals. It seems reasonable to assume that historically, the gray wolf (Canis lupis) may have had the 

same effects on horse-population growth as reported for mountain lion. An unnatural cause, illegal 

killing, is also an unfortunate mortality agent. Where predation is not a factor, natural causes such as 

starvation, dehydration, disease, and injury are the primary wild-horse mortality agents. In a typical 

Rawlins wild-horse population, the highest mortality rates are for the young in their first winter (BLM 

2005b). 

Wild horses generally prefer perennial grass species as forage. Shrubs are more important during the fall 

and winter. On the CD-C project area, the species of grasses preferred depends on the season of the year. 

Needle-and-thread and Indian ricegrass are most important during the winter and spring, and wheat 

grasses during the summer and fall (BLM 2005b). Crane et al. (1997) determined that wild horses in 

south-central Wyoming spent about 61 percent of their daytime hours feeding and selected stream-sides, 

bogs/meadows, and mountain big sagebrush habitats over low sagebrush habitats. Sedges (Carex sp.) 

were an important component in the horses’ spring/summer diet. This study concluded that palatability 

and abundance of graminoid vegetation and proximity to preferred habitats seemed to be the primary 

influences on habitat selection by wild horses within their study area. 

Several studies address the question of direct competition (displacing a species when they arrive) and 

indirect competition (use of the same resources). Olsen and Hanson (1977) conducted a study to 

determine dietary overlaps and composition between wild horses, cattle, elk, sheep, and pronghorns in the 

Wyoming Red Desert. The percent of season dietary overlaps were most noticeable between wild horses, 

cattle, and elk. The study also showed that wild horses, cattle, and elk seemed to be tolerant of feeding on 

the same plants in different seasons and the strategy of grazing differed among species. Although this 

study only focused on the Red Desert area, there was enough variation in selection of diets between the 

different species that there was minimal overlap for the same resources. 

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In a similar study conducted in southeastern Oregon, McInnis and Vavra (1987) found that at least 88 

percent of the mean annual diets of feral horses and cattle consisted of grasses. The researchers concluded 

that because dietary overlap between horses and cattle was high each season (62–78 percent), a strong 

potential existed for exploitive competition under conditions of limited forage availability (e.g., extended 

drought effects). McInnis and Vavra (1987) also determined in this two-year study that dietary overlap 

between horses and pronghorn varied from 7 percent (summer) to 26 percent (winter). Overlap between 

pronghorn and cattle varied from 8 percent (winter) to 25 percent (spring), suggesting that noncompetitive coexistence (indirect competition) between pronghorn, wild horses, and cattle was possible at 

this level of dietary overlap. It is important to remember that even if species have the same diets, as long 

as there are adequate resource supplies there will be no competition. Only when resources are limited 

does direct competition occur. 

Animal sizes vary and forage requirements change with the size of the animal. Similarly, different classes 

of livestock and different species of wildlife have varying requirements depending on size and maturity. 

Animal unit equivalents (AUEs) have been calculated for various kinds and sizes of animals. Table 3.10-

1 shows the most commonly used animal unit equivalents of various animal species in relation to a 

mature horse. 

Table 3.10-1. Commonly used Animal Unit Equivalents 

Class of Animal Animal Unit Equivalent 

(AUE) 

Cow, 1000 lb, dry 0.92 

Cow, 1000 lb, with calf 1.00 

Bull, mature 1.35 

Cattle, 1 year old 0.60 

Cattle, 2 years old 0.80 

Horse, mature 1.25 

Sheep, mature 0.20 

Lamb, 1 year old 0.15 

Goat, mature 0.15 

Kid, 1 year old 0.10 

Antelope, mature 0.20 

Bison, mature 1.00 

Deer, white-tailed, mature 0.15 

Deer, mule, mature 0.20 

Elk, mature 0.60 

Sheep, bighorn, mature 0.20 

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 HUMAN ENVIRONMENT 

3.11 VISUAL RESOURCES 

3.11.1 Visual Resources Characteristics 

As described in Section 3.1.1 Geology, the CD-C project area is part of a semiarid desert dominated by 

patches and thickets of sagebrush. Along larger drainages, grasses, greasewood, brush, lichens, 

cottonwood, and other plants accompany the sagebrush stands. Colors of gray, brown, and olive 

characterize the vegetation, with grasses and forbs changing to shades of brown as they cure in the 

summer and fall. Soils and rock strata are shades of red, gray, and brown. 

The project area is wholly within the Intermountain Semi-Desert Province of Southwestern Wyoming. 

North of Wamsutter, the project area lies within and comprises a large part of the Great Divide Basin 

section as a whole. The rest of the project area is almost entirely within the northeastern part of the 

Washakie Basin subsection of the Green River Basin section (Reiners and Thurston 1996). Rolling plains 

cover the Great Divide Basin part of the project area. The landscape is generally unbroken, so visual 

contrast draws attention wherever it occurs. Dune fields and playas (dry lakebeds) break up the sagebrush 

plain north of I-80. Elsewhere, cuestas (rims), occasional escarpments, and eroded streambeds create 

some visual contrast. 

West of the Red Desert Road (BLM 3207) is a feature that USGS maps label the Red Desert Basin; this 

area possesses a pebbly soil with a distinctive reddishness that shows through the scattered sagebrush. 

The sand dunes of the northern part of the project area are part of a widespread dunes complex; dunes in 

the project area are mostly vegetated in contrast to the active, mostly bare dunes at Killpecker Creek, 

which is north of Rock Springs and far to the west of the project area. 

The Chain Lakes Basin is part of a large playa complex that coincides with the Chain Lakes Wildlife 

Habitat Management Area in the northeastern part of the project area. Panoramic views of this area to the 

north of Chain Lakes Rim show these seasonal wetlands, which dry out to white alkaline flats. The 

occasional springs of Battle Springs Flat, west of Chain Lakes, support considerable greenery. 

The extended Delaney Rim-Wamsutter Rim cuesta-and-valley complex divides the northern Great Divide 

Basin section of the project area from the Washakie Basin in the south. Panoramas of the central and 

northern portion of the project area present themselves from Delaney Rim, and the rim complex itself is 

the most prominent geologic feature visible from I-80 as the highway crosses the Great Divide Basin. 

Eroded streambeds occur in the southern part of the project area; a key example is the deeply entrenched 

gully system in the lower reach of Muddy Creek. Little Robbers Gulch Reservoir, an agricultural pond far 

to the south within the project area, is a “social” recreation site (undeveloped and unmanaged) where 

usage fluctuates with the water level. Flat Top Mountain in the far south of the project area includes 

North Flat Top peak, the high point in the project area. This feature, Little Robbers Gulch, and The Bluffs 

are prominent geologic features visible from Wyoming Highway (WY) 789, the major north-south road 

through the southern part of the project area. 

Cultural modification in the project area includes open disturbance, disturbed areas that are undergoing 

reclamation but do not yet blend into the landscape, and many structures. Visible in many parts of the 

project area are infrastructure (roads, power lines, and buried pipeline corridors), ranch improvements 

(homesteads, shearing sheds, fencing, and water impoundments) and oil and gas development (active drill 

sites and production and transportation facilities). 

Oil and gas development, ongoing since the 1950s, comprises more than 4,400 natural gas wells in the 

project area. This surface disturbance is currently 49,218 acres (4.6 percent of the project area) of which 

8,472 acres (0.8 percent) remain unvegetated and in use over the long term for facilities such as roads, 

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CHAPTER 3—AFFECTED ENVIRONMENT—VISUAL RESOURCES
 

well-production facilities, and pipeline facilities. The most common type of disturbance—more than 

26,000 acres, or 2.4 percent—is from pipelines crossing the project area. An additional 10,958 acres have 

been disturbed for development other than oil and gas; this includes mainly federal, state, and county 

highways and roads, plus agricultural improvements. 

The potentially affected scenic quality in the project area is low to moderate overall. Cultural 

modification due to oil and gas development has negatively affected scenic quality in seven of 15 

identified landscape-rating units that are contained wholly or in part within the project area. This is 

generally because oil and gas development disturbs existing vegetation and introduces structures, with 

unnatural forms, lines, colors, and textures that contrast with the natural landscape character. In one of the 

seven landscape rating units found in the project area, the contrast introduced by existing oil and gas 

development is seen, attracts attention, and “in places is fairly dominant visually” (BLM 2011a). 

I-80 bisects the project area from east to west. Because of high traffic volumes, I-80 is the vantage point 

from which potentially the most viewers see the project area. Views from I-80 are mainly of the Great 

Divide Basin portion of the project area, with the isolated mountains, uplands, and rims (among them 

Delaney Rim, as noted above) in the middle-ground, background, and skyline. Foreground and middleground views from the highway often contain residential, commercial, or industrial structures. Through 

travelers and trucks are the predominant users of I-80, and high prevailing speeds mean that motorists see 

any given part of the landscape for a short time. 

Historically, WY 789 from Creston Junction to Baggs, Wyoming and Craig, Colorado, offered 

opportunities for pleasure driving and recreational access in the southern part of the project area. In the 

past five years, truck traffic on WY 789, mostly attributed to gas-field and interstate pipeline 

development, has grown almost twice as fast as other types of traffic. The Wyoming Department of 

Transportation (WYDOT) (Section 3.16 Transportation) now rates the traffic stream on WY 789 at less 

than “free-flowing.” Such traffic characteristics may discourage use of WY 789 for pleasure driving and 

sightseeing. 

The principal county road through the project area—the Wamsutter–Dad/Wamsutter–Crooks Gap Road 

South (Carbon County Road [CCR] 701/Sweetwater County Road [SCR] 23S)—is now primarily a 

natural gas industry access road. This two-lane gravel road may be busier than any other road serving the 

project area except I-80. It receives high levels of heavy and overweight vehicle use, with truck traffic 

often moving at high speed and creating considerable dust (Section 3.16 Transportation). These 

characteristics now discourage use of this road for casual recreational use except as an access to other 

interior roads. 

As described in Section 3.16 Transportation, almost all of the 33 other interior roads of the project area 

were originally intended for agricultural use, with consumptive wildlife recreation also being a common 

use that is traditionally related to agricultural landscapes and lifestyles. In recent years, the many interior 

roads have seen increasing use for natural gas industry access. Only three of 27 interior roads owned by 

BLM possess right-of-way agreements for all of the private lands that the roads cross. These are Road 

3207 (Red Desert Road), Road 3316 (Robbers Gulch Road) and Road 3321 (Little Robber Road). 

Therefore, recreation is a historical and current use of the other 24 interior roads but is subject to private 

landowner decisions about access. 

Because of the extensive road network, all land within the project area is in the foreground or middle 

ground of major or other roads (BLM 2011a). Increasing use by oil and gas workers lowers the level of 

sensitivity of many interior roads because of the low to moderate concern for scenic quality of most users 

in the context of low to moderate total use (BLM 2011a). For VRM sensitivity ratings, foreground and 

middle ground are treated alike and represent a distance of up to 3 to 5 miles (BLM 2011a). 

The Overland Trail corridor through the project area is an exception because the trail corridor is identified 

as a special management area in the RFO’s RMP. The corridor has high sensitivity to scenic quality by 

definition because of its special area status and because of the interest it attracts as part of the most 

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important historic trail in southern Wyoming (BLM 2011a). The trail corridor is described in Section 3.14 

Cultural and Historical Resources. 

3.11.2 Visual Resources Management System 

Visual resources in the project area fall under the BLM’s visual resource management (VRM) system. 

Guidance to manage visual resources is found in BLM Land Use Planning Handbook H-1601-1, 

Appendix C (BLM 2005c). Land use planning decisions mandate BLM to manage visual resource values 

in accordance with VRM objectives, which directly correspond to the assignment of all land to a VRM 

class. The BLM designates VRM classes for all land by inventorying the visual resources and by taking 

into account management considerations for other land uses. VRM classes may differ from VRM 

inventory classes because of management priorities for land use (BLM Land Use Planning Handbook H1601-1, Appendix C, Page 11). 

The BLM VRM classification system recognizes four VRM classes (Classes I through IV) based on 

scenic quality, visual sensitivity levels, and viewer distance zones. Each VRM classification has a 

management objective, as described below: 

Class I. The objective of Class I is to preserve the existing character of the landscape. This class provides 

for natural ecological changes; however, it does not preclude very limited management activities. The 

level of change to the characteristic landscape should be very low and should not attract attention. 

Class II. The objective of Class II is to retain the existing character of the landscape. The level of change 

to the landscape should be low. Management activities may be seen but should not attract the attention of 

the casual observer. Any changes to the landscape must repeat the basic elements of form, line, color, and 

texture found in the predominant natural features of the characteristic landscape. 

Class III. The objective of Class III is to partially retain the existing character of the landscape. The level 

of change to the landscape should be moderate. Management activities may attract the attention of the 

casual observer but should not dominate the view of the casual observer. Changes should repeat the basic 

elements found in the predominant natural features of the characteristic landscape. 

Class IV. The objective of Class IV is to provide for management activities that require major 

modifications to the existing character of the landscape. The level of change to the landscape can be high. 

The management activities may dominate the view and may be the major focus of viewer attention. Every 

attempt should be made to minimize the impact of these activities through careful location, minimal 

disturbance, and repetition of the basic visual elements of form, line, color, and texture. 

3.11.3 Visual Resources Management Class Designations 

VRM classes for the project area were established by the Rawlins RMP issued in December 2008. During 

preparation of the Approved RMP, a protest was lodged concerning visual resource values within the 

RFO. As a result, the BLM-preferred VRM decisions in the Proposed RMP/Final EIS were remanded, in 

accordance with guidance in the BLM Land Use Planning Handbook, H-1601-1. 

Map 3.11-1 compares oil and gas development extant in the project area as of 2009 to the VRM 

classification set by the 1990 Great Divide Resource Management Plan (GDRMP) (BLM 1990). The 

1990 GDRMP remained in effect as the RFO undertook the process of amending the RMP. Map 3.11-1 

illustrates why there is a potential for conflict in jointly managing oil and gas development and visual 

resources in the RFO. The potential was identified by BLM in the GDRMP FEIS: 

The widespread development of petroleum, natural gas, and coal in the RMPPA is creating direct, 

negative visual impacts within the RMPPA. Currently, visual mitigation of this activity is preventing 

mineral development activities from exceeding the established VRM objectives within these areas. 

The trend toward continued expansion of natural resource development is creating areas of potential 

conflict between this activity and the established VRM class objectives . . . Utilities are also having 

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CHAPTER 3—AFFECTED ENVIRONMENT—VISUAL RESOURCES
 

an increasing visual impact in the RMPPA. Even buried fiber-optic lines leave obvious visual effects. 

...Although visual sensitivity is clearly not the highest priority for many residents and visitors, as 

increasing numbers of sightseers and persons seeking various types of recreational opportunities pass 

through the RMPPA, an awareness of scenic values and the existing scenic quality grows for some 

residents and visitors. 

The RFO is in the process of updating the classification of its visual resources. However, until that 

process is complete, the RFO must, under the remand, use the VRM classification described in the No 

Action Alternative (Alternative 1) of the Proposed RMP/FEIS. Map 3.11-1 reflects that classification 

scheme as it applies to the project area. The classification shown on Map 3.11-1 is simply the 

classification carried forward from the 1990 GDRMP. 

As Map 3.11-1 shows, the project area has mixed land-ownership. This means that some state and private 

land within a given VRM classification may not be subject to BLM administration, which applies only 

where the federal government owns the surface or the oil and gas beneath the surface. This distinction is 

reflected in the analysis of the land within the project area as presented in Table 3.11-1. About 60 percent 

of the total project area is VRM Class III; the remainder is VRM Class IV. However, BLM’s authority to 

manage visual resources is limited to an estimated 62 percent of the total land area in VRM Class III and 

55 percent of the total land area in VRM Class IV. The remainder of the land in each class is exempt from 

BLM VRM management objectives because the surface and minerals are private or state owned. 

Table 3.11-1. Total and BLM-administered land area in the project area by VRM Class 

VRM Class 

Designation 

Land Area 

(thousands of 

acres) 

VRM Class Share of 

Total Land Area 

BLM-Administered 

Land (thousands of 

acres) 

Share of BLMAdministered Land 

within Class 

Class III 639 60% 393 62% 

Class IV 431 40% 237 55% 

3.11.4 Visual Resource Inventory of February 2011 

The RFO began the process of updating its VRM objectives with a formal visual resource inventory 

(VRI) prepared in compliance with BLM Manual 8400, Visual Resource Management, and BLM Manual 

8410, Visual Resource Inventory. The results of the completed inventory were published in February of 

2011 (BLM 2011a). The publication of the updated VRI completes the first step of the process called for 

by the administrative remand described in Section 3.11.3 above. Using the updated inventory as a 

baseline, further steps remain to be completed to amend the RMP and to update the VRM classifications 

of BLM-administered lands in the RFO. 

Information from the published VRI (BLM 2011a) has been used in this section to describe and 

characterize the affected visual resource environment of the CD-C project area as it exists now. However, 

the evaluations found in the inventory are not to be considered a VRM classification now or even, 

perhaps, the VRM classification that may be enacted in the future. No re-classification may occur until 

the RFO completes the entire RMP amendment process. Until then, as noted in Section 3.11.3, the RFO 

must use the 1990 VRM classifications. 

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Map 3.11-1. Current VRM Classification of land within the CD-C project area with comparison to 

existing well development 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

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CHAPTER 3—AFFECTED ENVIRONMENT—RECREATION
 

3.11.5 Visual Resources Management RMP Amendment 

As noted in Section 3.11.3, the BLM completed the RFO RMP revision in December 2008, but a protest 

was lodged concerning visual resource values within the RMP planning area, which includes the CD-C 

project area. To resolve the protest issue, the RFO is conducting additional planning, beginning with the 

update of the RFO visual resource inventory described in Section 3.11.4.

10 

In April of 2012 BLM published a formal Notice of Intent (NOI) (Federal Register 2012a) to prepare an 

amendment to the VRM sections of the RFO RMP along with the required environmental assessment 

(EA) and began the amendment process with a 30-day public scoping period that ended May 11, 2012. 

The BLM intends to finalize the EA and VRM amendment by the end of 2013. 

3.12 RECREATION 

3.12.1 Recreation Resources 

The main recreation resource of the project area is the public land managed by the BLM and the WGFD. 

This section discusses their use primarily for hunting and secondarily for pleasure driving to view 

wildlife, especially wild horses. No developed recreation sites exist within the CD-C project area. 

Dispersed recreational activity occurs wherever resources and access afford the opportunity. There is one 

undeveloped recreation site near the southern boundary of the project area, Little Robbers Gulch 

Reservoir, which has been historically used as a group hunting camp and fishing hole. 

The project area is entirely within the Western Extensive Recreation Management Area (ERMA), a 

management classification of the RFO established by the Rawlins RMP. For the Western ERMA, the 

Rawlins RMP directs management to consider three recreation objectives: (1) provide for the health and 

safety of visitors, (2) prevent or mitigate resource damage resulting from recreation uses, and (3) 

coordinate with other programs to minimize conflicts and adverse impacts on recreational opportunities 

[emphasis supplied]. 

The project area is not part of any of the Special Recreation Management Areas (SRMAs) otherwise 

designated by the Rawlins RMP. This means that none of the areas with a high priority for recreation 

management in the RFO are to be found in the project area. The only feature in the project area that has a 

recreational aspect, and for which there is an explicit management directive in the Rawlins RMP with 

implications for recreational use, is the undeveloped recreation site at Little Robbers Gulch Reservoir. 

One prescribed management action is targeted towards undeveloped recreation sites, such as Little 

Robbers Gulch Reservoir: the action opens a recreation site and its surrounding quarter-mile area to future 

oil and gas leasing with a “no surface occupancy” (NSO) stipulation. This means development of 

minerals directly under the restricted area may be undertaken by locating the necessary facilities outside 

of the restricted area. Although this primarily agricultural reservoir historically has been used as a 

hunters’ camp and fishing hole, it has recently been used less than in the past because of fluctuation in the 

water level. 

BLM considers most of the project area to be Front Country, where improved roads are generally within 

1/2 mile of recreation activity. This character prevails because of numerous improved roads in the 

Western ERMA that have been developed for oil and gas. Front Country is the second-most abundant 

class of recreation lands in the RFO according to the Rawlins RMP (BLM 2008a). Management affecting 

the Front Country recreation settings in the project area is guided by the objectives and actions 

10 This additional planning will not include the decision area for the Chokecherry/Sierra Madre wind energy project because a VRM 

amendment to the Rawlins RMP was considered separately as part of the NEPA process associated with the review of the 

Chokecherry/Sierra Madre wind energy project. 

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enumerated in the Rawlins RMP as described above. Indirectly, the recreation setting is affected by the 

VRM objectives established for the project area by the Rawlins RMP because the visual quality of an area 

is an important physical and social attribute of a recreation setting. (The Affected Environment for Visual 

Resources is described in Section 3.11 and Environmental Consequences for Visual Resources are 

described in Section 4.11.). 

3.12.1.1 Wildlife Resources 

The existing environment for wildlife in the project area is discussed in Section 3.8 Wildlife. The big 

game wildlife resource supports hunting, which is the main recreation use of the project area. Hunting in 

the project area is mainly for pronghorn, but hunters also pursue mule deer and elk. Wild-horse viewing is 

another wildlife recreation use in the project area. 

Commercial hunting guides using BLM land in the project area do so by obtaining a Special Recreation 

Permit (SRP) from the RFO. Nineteen hunting guides who hold permits to hunt on the WGFD Hunt 

Areas that overlap the project area also hold SRPs in the RFO. The project area is likely to be a small 

percentage of the total area upon which these hunting guides base their commercial operations. 

Information for determining the amount of use by these guides in the project area is not available from 

BLM records. 

A main hunting resource in the northern part of the project area is the Chain Lakes Wildlife Habitat 

Management Area (WHMA) about 32 miles northwest of Rawlins. The Chain Lakes WHMA provides 

winter habitat and a seasonal migration corridor for pronghorn. Agreements provide hunter access 

throughout the WHMA despite its location in the “checkerboard,” the area of alternating one-square-mile 

sections of public and private land. By agreement with the WGFD, the Rawlins RMP opens the WHMA 

to future oil and gas leasing but with intensive management of surface-disturbing and disruptive activities. 

The wildlife resources of the northern part of the project area also include a block of about 135,000 acres 

of contiguous public land northwest of the WHMA (WGFD 2007b). 

Wildlife resources in the southern part of the project area include the WGFD Carbon County Walk-In 

Area #1 located six miles southeast of Creston Junction. The WGFD walk-in program allows hunters to 

enter private land sections in the checkerboard without prior permission. The project area contains 15 

sections of Walk-In Area #1 (9,600 acres), about half of which are privately owned. The remainder is 

outside of the project area, where it adjoins the 25,600-acre Red Rim-Daley WHMA, also located in the 

checkerboard of intermingled public and private land. Ready access for recreation is also available in the 

southern tip of the project area where there is another large, continuous block of public land. This block 

of public land includes upland habitat in the Flat Top Mountain range and its larger drainages, Blue Gap 

Draw, Robbers Gulch, and Little Robbers Gulch. Little Robbers Gulch also contains the undeveloped 

recreation site used as a hunters’ camp at Little Robbers Gulch Reservoir, as described above. 

3.12.1.2 Other Recreation Resources 

A network of small roads and two-tracks covers the project area. Increasingly, traffic has come to be 

dominated by vehicles related to oil and gas field-development and maintenance, but the roads continue to 

be used for range management and recreation. Full public access for all uses, including recreation, is 

available on I-80, WY 789, and Carbon and Sweetwater County roads. The BLM interior road network 

comprises 27 numbered routes. However, casual use without permission is limited to three roads where 

the BLM possesses full right-of-way agreements. These include Road 3207 (Red Desert Road), Road 

3316 (Robbers Gulch Road) and Road 3321 (Little Robber Road). Private resource roads comprising the 

interior network of areas with gas development are generally open to the public. 

Recreational off-highway vehicle (OHV) use occurs in the project area; however, such OHV use is 

typically for the scouting activity that is ancillary to big game hunting rather than it being a primary 

recreation activity. 

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Non-consumptive use, which is mostly driving the roads to view wild horses or the Red Desert landscape, 

is much less common than hunting. The resources that support these activities are located north of I-80 

and are accessed from SCR 67 (Tipton-North Road) and BLM Road 3207 (Red Desert Road). Flat Top 

Mountain in the project area south of I-80 also attracts some recreation because of the visual resource 

(sightseeing, painting and photography of the mountain and from the overlooks it provides) and by the 

recreational setting (OHV, snowmobiling, and non-motorized snow recreation). 

The Overland Historic Trail runs east and west across the southern part of the project area. Signage calls 

attention to a turnout with an interpretive plaque on WY 789 about 20 miles south of Creston Junction. 

This minor feature may attract sightseeing visits by trail enthusiasts. However, this is the only public 

access to the trail corridor in the project area. 

3.12.2 Recreational Use 

The BLM estimates recreation usage at the field-office level, so there are no data available on recreation 

participation and recreation visitor days specific to the CD-C project area. Relying on experience, fieldoffice personnel characterize recreation use in the project area as low overall and seasonal during the 

year, with most recreational use occurring during the fall big-game hunting seasons. 

The BLM generally views the project area as serving a statewide market for undeveloped recreation, 

especially the market comprising residents of Carbon County and nearby counties. However, there is 

considerable use of the area by non-resident hunters, especially pronghorn and mule deer hunters who are 

23 percent and 27 percent non-residents, respectively. The project area also occasionally attracts nonresident recreation users with special interests such as wild horses, the Red Desert landscape, and historic 

trails. Recreation in the project area is shown on Map 3.12-1. 

Table 3.12-1 presents data on hunting activity that indicate the level of hunting potentially occurring 

within the project area. The table shows the totals for the Hunt Areas that include the project area because 

the WGFD does not have information on sub-areas within Hunt Areas (WGFD 2010b). 

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CHAPTER 3—AFFECTED ENVIRONMENT—RECREATION 

Table 3.12-1. Indicators of hunting activity by species in WGFD Hunt Areas that include the CD-C 

project area, 2009 

Game 

Species 

Hunt Areas Involved 

(% of Hunt Area 

overlapping the project 

area) 

Total Active 

Hunters 

Average 

NonResident 

Hunters 

Average 

Hunter 

Success 

Average 

Days per 

Hunter 

Number of 

BLMPermitted 

Commercial 

Outfitters1 

Pronghorn 

Antelope 

53 Baggs (2%) 

55 Red Rim (28%) 

57 S. Wamsutter (38%) 

60 Table Rock (33%) 

61 Chain Lakes (31%)

 694 23% 92% 2.6 55 

Mule Deer 

82 Baggs (2%) 

84 Atlantic Rim (19%) 

98 Chain Lakes (31%) 

100 S. Wamsutter (38%) 

131 Steamboat (13%) 

4,646 27% 45% 4.1 55 

Elk 

21 Baggs (2%) 

100 Steamboat (14%) 

108 S. Rawlins (19%) 

118 Shamrock Hills (31%) 

124 Powder Rim (23%) 

3,057 16% 47% 5.9 55 

1

 Typical number of Special Recreation Permits for Rawlins Field Office. This number changes year to year and an exact number is 

not known due to the fact that other field offices hold permits for this area and little data was kept for any permit issued before 

2007. 

Source: WGFD Annual Report of Big & Trophy Game Harvest 2009. Rawlins Field Office for Number of BLM-permitted Commercial 

Outfitters. Analysis by Lloyd Levy Consulting LLC. 

An estimate based on map analysis is provided of the percentage of each Hunt Area that overlaps the CDC project area. In terms of acreage, the project area contains about 28 percent of the involved Hunt Areas 

and 22 percent of the involved Herd Units for pronghorn (the Baggs, Bitter Creek, and Red Desert Herd 

Units). Similarly, the project area contains about 20 percent of both the involved Hunt Areas and Herd 

Units for mule deer (the Baggs, Chain Lakes, and Steamboat Herd Units) and about 18 percent of the 

involved Hunt Areas and 16 percent of the involved Herd Units for elk (the Sierra Madre, Shamrock, 

Petition, and Steamboat Herd Units). These percentages roughly indicate the project area’s contribution to 

hunting activity based on these game populations. Additionally, the project area contains only about 2 

percent of the Baggs Hunt Area, which attracts by far the most hunters of all three big-game animals 

among the areas overlapping the project area. 

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CHAPTER 3—AFFECTED ENVIRONMENT—RECREATION
 

Map 3.12-1. Recreation in the CD-C project area 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

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CHAPTER 3—AFFECTED ENVIRONMENT—RECREATION
 

The total number of active pronghorn hunters using the Hunt Areas that overlap the project area rose from 

1,034 in 2002 to 1,955 in 2006 (up 89 percent). Following a modest drop in 2007, pronghorn hunters 

declined dramatically in 2008 to 620, then rose to 694 in 2009. Deer hunters in the relevant Hunt Areas 

rose to 4,918 in 2007—up 15 percent from 2002—then dropped slightly in 2008 (4,098) and 2009 

(4,646). Elk hunters rose to 3,767 in 2007—up 7 percent from 2006 but down 6 percent from 2002—then 

declined again to 3,057 in 2009—down 8 percent from 2007. Table 3.12-2 presents the total active 

hunters for each species from 2002 to 2009. 

Table 3.12-2.	 Number of active hunters by species in WGFD Hunt Areas that include the CD-C project 

area, 2002–2009 

Game 

Species 

Hunt Areas Involved 

(% of Hunt Area 

overlapping the project 

area) 

2002 2003 2004 2005 2006 2007 2008 2009 

Antelope 

53 Baggs (2%) 

55 Red Rim (28%) 

57 S. Wamsutter (38%) 

60 Table Rock (33%) 

61 Chain Lakes (31%) 

1,034 1,113 1,221 1,499 1,955 1,697 620 694 

Deer 

82 Baggs (2%) 

84 Atlantic Rim (19%) 

98 Chain Lakes (31%) 

100 S. Wamsutter (38%) 

131 Steamboat (13%) 

4,280 4,487 4,048 4,070 4,834 4,918 4,098 4,646 

Elk 

21 Baggs (2%) 

100 Steamboat (14%) 

108 S. Rawlins (19%) 

118 Shamrock Hills (31%) 

124 Powder Rim (23%) 

4,027 3,928 3,278 3,356 3,505 3,767 3,105 3,057 

Source: Wyoming Game and Fish. Harvest Reports (annual). Analysis by Lloyd Levy Consulting LLC. 

3.12.3 Recreation Trends 

Apart from long-term trends in popularity, the main factor determining the number of hunters using a 

particular Hunt Area is WGFD’s allocation of hunting licenses in response to demand and to gamemanagement policies that balance the demand for hunting with the supply of game. BLM personnel have 

observed that recreational use in the RFO area in general appears to be steady or in a slight upward trend. 

If favorable conditions for wildlife were sustained in the future, then hunting throughout the RFO would 

likely continue near current levels. A similar trend may be expected in the project area. 

OHV use in the project area that occurs in connection with hunting is limited to existing roads and twotracks by the OHV designations published in the Rawlins RMP, although travel off-road up to 300 yards 

is permitted to retrieve a downed game animal or to access a campsite. Despite limitations, the 

proliferation of authorized and unauthorized OHV routes is expanding rapidly, potentially detracting from 

the recreational setting. 

According to a survey in the Carbon County Land Use Plan, fishing, hunting, overnight camping, and 

nature appreciation are the four most important outdoor recreational activities to Carbon County residents. 

The plan notes that important outdoor recreational activities occur at facilities or on lands that are 

developed or managed by other agencies, so the plan encourages coordination to allow substantive input 

by the county into agency planning (Carbon County Board of Commissioners and Carbon County 

Planning Commission 1998). The land use plan contains no specific recreation plans for land within the 

project area. 

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CHAPTER 3—AFFECTED ENVIRONMENT—LANDS WITH WILDERNESS CHARACTERISTICS
 

Recreation is mentioned in the Sweetwater County Comprehensive Plan. The plan states that Sweetwater 

County goals and objectives relating to public lands and resources include a goal of promoting [public 

land management] agency awareness of County issues and interests: “These include, but are not limited 

to, natural resource exploration and development, multiple-use land and resource management practices, 

agriculture/ranching and recreation, and adequate public access to and across public lands” (Sweetwater 

County 2002). 

3.13 LANDS WITH WILDERNESS CHARACTERISTICS 

Lands with wilderness characteristics (LWCs) are blocks of public land possessing sufficient size, 

naturalness, and outstanding opportunities for either solitude or primitive and unconfined recreation, as 

defined in BLM Manual Section 6310 (BLM 2012f), Conducting Wilderness Characteristics Inventory on 

BLM Lands and Section 6320 (BLM 2012g), Considering Lands with Wilderness Characteristics in the 

BLM Land Use Planning Process. 

A roadless area of more than 5,000 acres of contiguous BLM land is generally the minimum for 

consideration as an LWC; smaller roadless areas of contiguous BLM land may be considered when they 

are adjacent to an area already formally determined to have wilderness character or potential. These BLM 

manual sections define current policy on LWCs, directing BLM to: 

1.	 Continue to conduct and maintain inventories regarding the presence or absence of wilderness 

characteristics; and 

2.	 Consider identified lands with wilderness characteristics in land use plans and when analyzing 

projects under the National Environmental Policy Act (NEPA). 

The policies stated in BLM Manual Sections 6310 and 6320 do not encompass wilderness areas already 

designated by Congress or formally identified Wilderness Study Areas (WSAs) which are pending before 

Congress and are managed as wilderness until a decision is made. Within the RFO, there are five WSAs, 

one of which—the Adobe Town WSA—is near the southwest boundary of the CD-C project area but does 

not overlay the project area. There are no designated wilderness areas in the RFO. 

Specifically to comply with BLM Manual Section 6320, the RFO is tiering this analysis of the Proposed 

Action and alternatives to the approved Rawlins RMP issued in 2008 (BLM 2008a and b). During the 

land use planning process leading to the approved RMP, the RFO reviewed several citizens’ proposals for 

new WSAs. The RFO responded to these proposals by conducting inventories to determine whether the 

affected lands possess the wilderness characteristics of size, naturalness, or outstanding opportunities for 

primitive, unconfined recreation or solitude, and found two areas located adjacent to existing WSAs that 

possess one or more of these characteristics. However, neither of the two areas—Adobe Town Fringe and 

West Ferris Mountains—lies within the CD-C project area (see Rawlins RMP Draft EIS Map 2-45, Areas 

with Wilderness Characteristics, viewable online at <http://www.blm.gov/pgdata/etc/medialib/blm/wy/­

programs/planning/rmps/rawlins/deis/maps.Par.89221.File.dat/48_Map2-45.pdf>). 

Although ineligible for designation by BLM as WSAs, the Adobe Town Fringe and West Ferris 

Mountains areas with wilderness characteristics were considered for special, protective management 

under the RFO’s land use planning authority and were evaluated to determine whether they were 

manageable as wilderness. The majority of the areas under consideration are leased for oil and gas 

development, in which case the RFO would not have the means to prevent impairment of any wilderness 

character that may be present. Therefore, “the BLM elected to manage lands with wilderness character for 

multiple use and not for protection of wilderness character” (Rawlins RMP ROD, p. 1-3). 

The RFO continues to update the inventory of public lands for wilderness characteristics. All new 

information regarding LWCs would be considered by the RFO in the future along with other resource 

information in developing and revising land use plans and when making subsequent project-level 

decisions. 

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CHAPTER 3—AFFECTED ENVIRONMENT—CULTURAL AND HISTORICAL RESOURCES 

3.14 CULTURAL AND HISTORICAL RESOURCES 

3.14.1 Cultural Chronology of the Area 

Archaeological investigations in the Great Divide Basin and the Washakie Basin indicate that the area has 

been inhabited by people for at least 12,000 years from Paleoindian occupation to the present. The 

accepted cultural chronology of the Great Divide and Washakie basins is based on a model for the 

Wyoming Basin by Metcalf (1987) and revised by Thompson and Pastor (1995). The prehistoric 

chronology of the Wyoming Basin, which includes the Great Divide and the Washakie basins, is 

documented in Table 3.14-1. 

Table 3.14-1. Prehistoric chronology of the Wyoming Basin 

Period Phase Age (B.P.) 

Paleoindian -- 12,000–8500 

Early Archaic Great Divide 8500–6500 

Early Archaic Opal 6500–4300 

Late Archaic Pine Spring 4300–2800 

Late Archaic Deadman Wash 2800–2000/1800 

Late Prehistoric Uinta 2000/1800–650 

Late Prehistoric Firehole 650–250 

B.P. = before present 

Source: Metcalf (1987), as modified by Thompson and Pastor (1995) 

Paleoindian Period 

The Paleoindian period is the oldest period for which there is archaeological evidence. It began ca. 12,000 

years B.P. and ended around 8500 B.P. This is the transitional period from the Wisconsin ice advance 

during the terminal Pleistocene to the warmer and drier climatic conditions of the Holocene. A savannahlike environment with higher precipitation than occurs today was prevalent in southwestern Wyoming. 

Understanding paleo-environmental conditions operating at the end of the Pleistocene and into the 

Holocene provides insights into the articulation between human populations and the environment 

(Thompson and Pastor 1995). Paleoindian sites are rare in southwestern Wyoming. Fifty-one sites have 

been documented to contain Paleoindian cultural material in the project area. One site includes a feature 

(a hearth) that dates to the Late Paleoindian period at 8840 ± 90 B.P. No cultural material was found with 

the hearth. 

Isolated surface finds of Paleoindian projectile points are not uncommon and suggest that site 

preservation may be a major factor affecting the number of known sites. Paleoindian lithic technology is 

distinctive with projectile points serving as chronological/cultural indicators within the period. 

Paleoindian tool assemblages include lanceolate points, gravers, and end-scrapers (Thompson and Pastor 

1995). Radiocarbon analysis of a mammoth tusk at one site dates the site to 11,000 B.P. 

Archaic Period 

Settlement and subsistence practices in southern Wyoming remained largely unchanged from the end of 

the Paleoindian period through the Archaic and continued until at least the introduction of the horse or 

even until historic contact. Reduced precipitation and warmer temperatures occurred ca. 8500 B.P. The 

environmental change at the end of the Paleoindian period led to a pattern of broad-spectrum resource 

exploitation, which is reflected in the subsistence and settlement practices of the Archaic period. The 

resource exploitation became more diverse during the Archaic period. Large side- and corner-notched dart 

points and housepits are found during the Archaic period, and the presence of groundstone implements 

suggests a greater use of plant resources during this period. Faunal assemblages from Archaic 

components document increased use of small animals (Thompson and Pastor 1995). 

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CHAPTER 3—AFFECTED ENVIRONMENT—CULTURAL AND HISTORICAL RESOURCES 

Late Prehistoric Period 

The Late Prehistoric period (2000-650 B.P.) is subdivided into the Uinta and the Firehole phases. Largescale seed processing and an increase in the number of features including roasting pits is noted in the Late 

Prehistoric period, as is the presence of pottery and the introduction of bow-and-arrow technology. A 

characteristic of the Uinta phase is clusters of semi-subterranean structures dating to ca. 1500 B.P. At 

least two different types of structures have been identified: a more substantial cold-weather habitation and 

a less substantial, warm-weather structure serving more as a windbreak. The Firehole phase is 

distinguished from the preceding Uinta phase by a dramatic decline in radiocarbon dates, possibly related 

to a decline in population density. 

Proto-Historic Period 

The Proto-Historic period begins sometime after 300 years B.P. with the first European trade goods to 

reach the area, and ends with the development of the Rocky Mountain fur trade 150 years ago. The 

Wyoming Basin was the heart of Shoshone territory during this period, with occasional forays into the 

area by other groups such as the Crow and Ute (Smith 1974). The most profound influence on native 

cultures during this time was the introduction of the horse, enabling Native Americans to expand their 

range. All forms of rock art denoting horses, metal implements, and other Euro-American goods are 

associated with the Proto-Historic period. Metal projectile points have been recovered from both surface 

and subsurface contexts in southwest Wyoming. 

Historic Period 

Historic use of the area is limited. Steep canyons, inadequate water supply, badlands, and escarpments 

make the area inhospitable for settlement with only limited ranching activities present. Historic site types 

include linear properties such as trails, railroads, and highways and associated sites such as stage stations, 

rail stations, and sidings. Other historic site types include cabins, historic inscriptions, mines, cemeteries, 

historic cairns, ranches, corrals, stock-herding sites, post offices, small towns, debris and trash dumps, 

monuments, and bridges. No homesteads have been documented in the project area. The Homestead Act 

of 1862 gave 160 acres to anyone who could pay a $10 registration fee and pledge to live on the property 

and cultivate the land. The Grazing Homestead Act of 1916 allowed grazing homesteads to file for 640 

acres of land. The Act was intended to help cattlemen. The federal government retained the mineral rights 

to the land. In 1934, the Taylor Grazing Act and associated Executive Order 6910 ordered lands 

withdrawn from further homesteading claims. These laws ensured the federal government would be the 

largest single landowner in Wyoming (Gardner and Johnson 1989). Several ranches or ranch-associated 

activities have been documented in the project area. Fur trapping and trading was not an important 

occurrence in the study area due to the lack of perennial streams. 

Linear historic sites are found within the study area. The Overland Trail crosses the mid-portion of the 

study area trending east to west. The Cherokee Trail transects the southern portion of the study area, 

trending east to west. The Rawlins–Baggs Road transects the southeastern portion of the study area, 

trending generally north to south. The road is located south of I-80 and east of WY 789. The Lincoln 

Highway and the original UPRR grade transect the project area trending east-west, generally paralleling 

south of the I-80 corridor. 

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CHAPTER 3—AFFECTED ENVIRONMENT—CULTURAL AND HISTORICAL RESOURCES 

Table 3.14-2. Historic chronology of the Great Divide Basin and the Washakie Basin 

Phase Age A.D. 

Proto-Historic 1720 – 1800 

Early Historic 1800 – 1842 

Pre-Territorial 1842 – 1868 

Territorial 1868 – 1890 

Expansion 1890 – 1920 

Depression 1920 – 1939 

Modern 1939 – Present 

Source: Massey 1989 

3.14.2 Summary of Extant Cultural Resources 

The project area encompasses approximately 1,680 sections of land for a total area of 1.1 million acres. 

The State of Wyoming Cultural Records Office in Laramie provided information on the previous work 

conducted and sites recorded in the project area. Records at Western Archaeological Services (WAS) 

were also consulted. There have been 20,473 cultural resource projects conducted and 4,860 sites 

recorded in the project area (prior to 2007). The inventoried area is comprised of 116,322 Block acres. 

The site density is 0.04 sites per acre. Many of the projects have been linear Class III cultural resource 

inventories for roads, pipelines, powerlines, and seismic projects. Block surveys include wells, 

compressor stations, and general block inventories. Other project types in the project area include Class I 

data reviews; Class II sampling surveys, monitors, and open-trench inspections; reclamation; range 

improvements; test excavations; data-recovery excavations; examination of ethnographic records; and 

historic record research. The total amount of open-trench inspections and monitors conducted in the 

project area has not been consistently recorded through the years. However, open-trench inspections on 

36 projects and blading monitors on 35 projects within the project area have resulted in discoveries. 

In southwest Wyoming, sand deposits (sand dunes, shadows, and sand sheets), alluvial deposits along 

major drainages, and colluvial deposits along the lower slopes of ridges are recognized as areas of higher 

archaeological sensitivity. Cultural resources are also likely to be found around internally drained playa 

lakes. 

3.14.3 Site Types 

Of the total of 4,860 sites recorded prior to 2007, 2,350 were located in Sweetwater County and 2,510 in 

Carbon County. Site types included: prehistoric sites (4,266), historic sites (281), and prehistoric/ historic 

sites (313). The total percentage for site types is: prehistoric sites (88 percent), historic sites (6 percent), 

and sites with prehistoric and historic components (6 percent). Of the recorded cultural resources, 0.04 

percent have been listed on the National Register (2 sites; 1 has been destroyed), 23 percent (1,127) are 

recommended eligible for nomination to the National Register of Historic Places (NRHP), 50 percent 

(3,443) are recommended not eligible for nomination to the NRHP, 25 percent (1,201) remain 

unevaluated, and 2 percent (87) have been destroyed. Cultural resources documented in the project area 

include prehistoric open camps, prehistoric lithic debris scatters, historic sites, and prehistoric/historic 

sites. The types of sites that have been previously identified or predicted to be in the project area are 

discussed below. 

3.14.3.1 Prehistoric Sites 

Prehistoric site types identified in the project area include sites dating to all time periods, burials, 

housepits, rock art, hunting blinds, stone circles, rock alignments, rock shelters, cairns, pottery sites, 

prehistoric camps, milling/vegetable-processing sites, butchering/bone-bed sites, lithic scatters, quarries, 

and primary and secondary procurement sites. Many of these sites have undergone data recovery and/or 

test excavations. 

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CHAPTER 3—AFFECTED ENVIRONMENT—CULTURAL AND HISTORICAL RESOURCES 

Prehistoric camps contain evidence of a broad range of activities including subsistence-related activities. 

Cultural remains include formal features such as fire hearths, stone rings, cairns, rock art, lithic debris, 

chipped stone tools, quarries, evidence of milling/vegetable-processing activities including ground stone, 

and pottery. Single as well as long-term occupation are represented. 

Lithic scatters consist of sites containing lithic debris such as debitage or stone tools. No features or 

feature remnants are found at the sites. The sites are interpreted as representing short-term activities. 

Quarries are sites where lithic raw material was obtained and initially processed. Primary and secondary 

lithic procurement areas are geologic locations where chert and quartzite cobbles have been redeposited 

and later used by prehistoric inhabitants for tool manufacture. Archaeological landscapes are secondary 

lithic procurement sites identified within the project area. Landscapes are by definition not eligible to the 

National Register. 

Human burials, rock art (both pictographs and petroglyphs), rock alignment sites, and rock shelters have 

been identified as sensitive or sacred to Native Americans. Few such sites have been located in all of 

southwestern Wyoming. Numerous stone circle and/or cairn sites have been identified in the project area. 

Prehistoric cairns are usually found along ridges overlooking seasonal drainages. Three rock shelters have 

been documented in the project area. One site in the study area contains prehistoric and historic rock art 

(Romanowski 1998), where two separate panels were identified. The southeast-facing panel contains a 

prehistoric zoomorphic figure near the top, similar to a horse or buffalo. Also noted were vertical 

scratches representing claw marks. The same panel contains a historic figure near the base. The second 

panel faces east and contains historic and modern petroglyphs. 

Housepits are found throughout the study area, and radiocarbon analysis dated two internal features to 

5900 B.P. 

Pottery/ceramics have been documented in the project area as well as numerous pottery sites in 

southwestern Wyoming and northwestern Colorado. Small sherds from unknown vessel types were 

recovered from most of the sites, and one nearly complete corrugated pot was collected. 

Prehistoric/historic site types (313) include prehistoric camp/historic debris scatters and prehistoric lithic 

scatters/historic debris scatters. These multi-occupation sites exhibit mixed surface components. 

Generally the historic components of these mixed sites are associated with transportation or sheepherding activities. 

Numerous sites have recently been excavated in the study area, and a data synthesis was compiled for the 

Rawlins RMP, greatly increasing the knowledge of hunter/gatherer subsistence strategies in the area. One 

site excavated as a result of the CIG Uinta Basin Lateral pipeline dates between 9300–1730 B.P. (Pool 

2000). Five components have been identified at the Salamander site ranging from the Early Archaic 

period through the Late Prehistoric period (Fleming 2004). Other excavated sites in the project area have 

dated to the Late Archaic period and the Late Prehistoric period. 

3.14.3.2 Historic Sites 

A total of 281 historic sites have been documented in the project area. Site types include historic trails, 

stage roads, stage stations, ranches, cairns, and debris. Eligible historic linear sites that cross portions of 

the project area include the Overland Trail, the Cherokee Trail, the Rawlins–Baggs Road, the Lincoln 

Highway, and the UPRR. The Overland Trail crosses the south-central portion of the project area, the 

Cherokee Trail crosses the southern portion, and the Rawlins–Baggs Road transects the southeastern 

portion of the project area. The Lincoln Highway and the UPRR (original grade) trend east-west through 

the central portion of the project area and are located within an area known as the “Southern Corridor.” 

As part of planning for the project area, the Lincoln Highway and original grade of the UPRR were 

identified and evaluated. BLM has accepted the evaluation with SHPO concurrence. 

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CHAPTER 3—AFFECTED ENVIRONMENT—CULTURAL AND HISTORICAL RESOURCES 

Several sites are associated with the UPRR including sidings, rail camps, bridges, a culvert, and variations 

on the original grade. Five railroad sidings have been documented. Six railroad stations have been 

reported. Four bridges have been documented along the UPRR mainline. Other sites associated with the 

railroad include foundations, camp debris, a shed, and a dugout. 

Towns and post offices played a part in the settlement of the project area. Towns were located along the 

UPRR and the Lincoln Highway. A post office, ranch, and stage stop were located at Dad, along the 

Rawlins–Baggs Road. Recorded communities along the tracks or highway include Tipton, Red Desert, 

Wamsutter, and Creston Junction. A “truss bridge” crossing Muddy Creek is considered eligible for 

nomination to the National Register. 

The Cherokee Trail was used in the 1850s by members of the Cherokee Tribe moving from the Oklahoma 

Reservation to the California gold fields. A southern variant of the Cherokee Trail trends southwest, 

crossing Savory Creek, and staying south of Ketchum and Five Buttes. The trail crosses the South Fork of 

Cherokee Creek and then Smiley Draw, remaining south of Cherokee Creek. The road continues west, 

with Wild Horse Butte to the south, descending to the Muddy Creek drainage and continuing west 

through Blue Gap Draw. The Cherokee Trail through the project area was identified and evaluated as part 

of this project (Johnson 2006). As with any of the westward migratory trails of the mid-1800s, variants 

have been documented. Reasons for variations in routes include inaccessibility at certain times of year or 

members of the group may have traveled the route previously and found an easier or more direct avenue 

to water. 

The Cherokee Trail has received a great deal of attention by writers and even the film industry. LeRoy 

Hafen, in his work The Overland Mail, contends that the pioneering efforts of the Cherokee Indians led to 

the eventual development of the Overland Trail. The net result of the combined effort of novelists, 

historians, and the media has been to create a highly romanticized trail that is still not well understood in 

terms of the people who used it and the location of the actual route taken by Cherokees traveling west 

from Oklahoma to California in 1850 (Gardner 1999). 

Excerpts from a Cherokee Trail diarist found in Cherokee Trail Diaries (Fletcher et al. 1999) document 

stops along the southern variant of the Cherokee Trail. Mitchell (1850):

 “June 30 Sunday . . . frosty and plenty of ice We took an object west [possibly Five Buttes] at a 

great distance west to travel to and had great trouble in getting to it Too many bluffs & bad 

branches in the way In the evening we got out of the mountains & got to a bad Swamp creek runing 

south [This is Muddy Creek north of Baggs, WY] Supposed to be a for of elk head [Little Snake] 7 of 

our men were dissatisfied with the corse we were travling & left us taking a more South corse” 

The Overland Trail is recommended as eligible for inclusion on the NRHP. The Overland Trail goes 

through the project area, traversing the checkerboard land pattern, and has been previously evaluated with 

BLM and SHPO concurrence (Johnson et al. 2005). This evaluation included the associated stage 

stations. Duck Lake Stage Station, Coal Gulch Stage Station, and the Washakie Stage Station were stops 

along the Overland Trail. Gardner et al. (1993) states: “Construction of stage stations at Sulphur Springs, 

Washakie, and Duck Lake more than likely took place in 1862.” This time frame coincides with Ben 

Holladay beginning his Overland Stage venture to connect Denver, Colorado, with Salt Lake City, Utah. 

“Home” stations offered travelers more amenities than “swing” stations where a change of horses 

occurred and travelers’ meals were offered. Robert Foote, giving testimony to Senator Cameron during a 

request for reimbursement for destruction caused by Native Americans, stated that “Stations from Sulphur 

Springs west to Fort Bridger were built from stone.” (Gardner et al. 1993) Along with the construction of 

the stage stations was the stringing of the telegraph wires. Freighters as well as emigrants used these 

routes. 

The Rawlins-to-Baggs Stage Road is an eligible freight and stage road. Mail, goods, and passengers 

followed the road on freight wagons and the Overland Stage. The road is first documented in 1881 and 

there were subsequent stage stations built along the route. Only the southern tip of the project area 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 3-143 
CHAPTER 3—AFFECTED ENVIRONMENT—CULTURAL AND HISTORICAL RESOURCES 

overlaps the Rawlins-to-Baggs Stage Road. The entire segment of the stage road through the project area 

has been previously determined as not contributing to the overall eligibility of the road (Rosenberg 2006). 

Seven historic rock-art inscriptions have been documented in the project area. The Overland Rock 

contains inscriptions associated with the Overland Trail and is listed on the National Register. Three sites 

are documented to contain historic rock inscriptions associated with sheep ranching. Nine historic ranches 

are documented within the project area and several additional buildings, foundations, corrals, and fences 

are ranch-associated. The ranches are generally associated with raising sheep. In Wyoming, large-scale 

sheep ranching did not appear until the latter decades of the 1800s; by 1920, however, it was one of the 

pillars of the state’s economic base. Ranching families promoted economic wealth with hard work and by 

taking chances, such as expanding across the desert of southwest Wyoming. Ranching/stock-herding sites 

in the area are generally sheepherder camps exhibiting hole-in-top cans and purple glass. Refuse left 

behind from tending herds is usually located on terrain with water as well as a good view to watch over 

the herds. One historic log cabin has been documented in the study area. Also reported at the cabin site 

are a tipi ring and two fire pits. A wild-horse trap is reported in the project area. 

Historic cairns, often associated with sheep-herding, are located on ridges or high points, sometimes 

overlooking seasonal drainages. 

Historic debris/trash sites are found distributed throughout the project area. These scatters usually include 

trash associated with emigration and ranching/herding activities—condensed-milk cans, food cans, baling 

wire, glass, and milled wood. The sites are usually found on ridge tops in areas with vegetative cover 

conducive for forage and bedding. 

One historic mine has been reported in the project area. The Bugas Mine is a small subsurface coal mine 

where low-grade coal was extracted, probably between 1950 and 1964. Gardner and Johnson (1991) 

recorded its location on a northeast-facing slope overlooking Hansen Draw, approximately one-half mile 

south of the Union Pacific Railroad and 2.5 miles northeast of Wamsutter. It is accessed by a faint twotrack road. The surface extent of the Bugas mine includes a 17-mile-long trench with a mine portal at the 

west end that is partially blocked with earth. At the east end of the trench is a broad, flat tailings pile of 

low-grade coal with some mica cut fragments mixed in. Some low-grade uranium ore was noted in the 

mica cut-bank of the trench. It is unknown if any reclamation work has been conducted at the mine since 

the initial recording in 1991. The site is recommended not eligible for nomination to the National Register 

of Historic Places. 

One grave, the Divide Burial, has been documented in the project area. The grave of a male Caucasian 

was located during the construction of a telecommunication line. The grave was located on Union Pacific 

land. Analysis of the human remains and associated coffin and grave goods indicate the male was about 

23 years of age and was probably a railroad worker. His remains were moved to the Rock Springs, 

Wyoming, cemetery. 

3.14.4 Summary 

Based on information derived from the data review, it is evident that prehistoric cultural resources are 

found along the major ephemeral drainages and along the lower benches of escarpments that dominate the 

terrain in the project area. Sensitive areas include drainages such as Muddy Creek, and other locales 

where water was or is present—natural springs, playa lakes, and the larger ephemeral washes that provide 

intermittent water sources. The numerous springs in the project area would be likely to contain cultural 

resources. Seasonal drainages flow into the project area from several escarpments such as Flat Top 

Mountain, North Flat Top Mountain, Baldy Butte, Pine Butte, Chain Lakes Rim, Ruby Knolls, Coal 

Butte, High Point, Sugarloaf, Horse Butte, Luman Butte, Horseshoe Bend, Siberia Ridge, Lost Creek 

Butte, Delaney Rim, Wells Bluffs, Wamsutter Rim, and Big Hill. Certain topographic settings have 

higher archaeological sensitivity: eolian deposits (sand dunes, shadows, and sheets), alluvial deposits 

along major drainages, and colluvial deposits along lower slopes of ridges. 

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CHAPTER 3—AFFECTED ENVIRONMENT—CULTURAL AND HISTORICAL RESOURCES 

Two areas within the study area are identified by the RFO as especially sensitive. The first consists of 

approximately 127 cairns along a ridge system in the southern portion of the study area, and the second 

consists of a dune complex that spans nine sections. A sensitivity model and treatment plan for the dune 

complex was compiled as part of the CD-C project. 

The subsistence and settlement patterns in the project area reflect a hunter-gatherer lifeway. Information 

about the Paleoindian period is sparse and is not well understood. Research into the subsistence and 

settlement patterns used during the Archaic period indicates summer occupations in the mountains, winter 

occupations in the foothills, and spring and fall movements utilizing all available zones (Creasman and 

Thompson 1997). Subsistence patterns in the Archaic period and the Late Prehistoric period are similar in 

that they are based on seasonal movement throughout the basins and foothills in response to the 

availability of floral and faunal resources (Creasman and Thompson 1997). A broad diet is evident in 

extensive procurement and processing of small mammals by 450 B.P. (Shimkin 1947), or possibly earlier 

(Bettinger and Baumhoff 1982). Numic-speaking Shoshonean groups occupied the Wyoming Basin and 

continued to reside there until Euro-American expansion relegated them to reservations beginning in 

1868. 

Historic use of the project area was limited by terrain and lack of perennial water sources. Ranches, 

limited irrigation, grazing, and limited ranching activities are identified by the historic debris scatters and 

historic record. Sheep ranching was an important industry historically, and continues today. Historic trails 

and stage stations are located within the project area including the Overland Trail, the Cherokee Trail, the 

UPRR (original grade), the Lincoln Highway, the Rawlins-to-Baggs Road, the Wamsutter-to-Baggs 

Road, and the Red Wash Wagon Road. Stage stations are associated with the Overland Trail and the 

Rawlins-to-Baggs Road. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 3-145 
Producing Wells 

3500
 

3000
 

2500
 

2000
 

1500
 

1000
 

500 

0 

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 

Figure 3.15-1. Producing oil and gas wells in Carbon and Sweetwater Counties, 2000–2010 

Carbon Sweetwater 

CHAPTER 3—AFFECTED ENVIRONMENT—SOCIOECONOMICS
 

3.15 SOCIOECONOMICS 

This section describes recent and current social and economic trends and conditions in and near the CD-C 

project area, the geographic area that would be primarily affected by the Proposed Action or alternatives. 

Information for this section was derived from a variety of published documents and from interviews with 

local officials and service administrators. A Baseline Socioeconomic Technical Report (STR) was 

prepared in 2008 (available on the BLM website for this document), which examined a wide range of 

socioeconomic conditions and trends in and near the project area. These trends have been monitored over 

time, updated, and are presented in this section of the EIS. 

Natural gas development has been ongoing in the project area for more than 50 years but the pace of such 

development accelerated between 1999 and 2004, then remained high through 2007/2008, contributing to 

an economic expansion in Carbon and Sweetwater counties during that same period. Natural gas 

development activity in the region was subsequently curtailed in the wake of the national economic 

recession that began in December 2007, the repercussions of which continue at the time of this 

assessment (mid-2011). 

Figure 3.15-1, which displays the total number of wells (which are mostly natural gas wells) in 

production in Carbon and Sweetwater counties between 2000 and 2010, illustrates the high levels of 

natural gas activity in the early to mid-years of the decade and the subsequent leveling-off of development 

in 2008–2009. Development began to accelerate again in Sweetwater County during 2010, but remained 

fairly flat in Carbon County. 

Socioeconomic effects of historic and ongoing oil and gas development in the project area and the twocounty area are included in this Affected Environment section, as information about these effects provides 

valuable insight into the potential effects of the Proposed Action and alternatives and the historic and 

cumulative contexts in which they would occur. The socioeconomic effects of the recent energy-related 

economic expansion and subsequent contraction are particularly illustrative of potential future 

socioeconomic effects of similar occurrences. This section also discusses the often cyclical nature of oil 

and gas development and the effects of those expansion and contraction cycles on socioeconomic 

conditions within the study area. 

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CHAPTER 3—AFFECTED ENVIRONMENT—SOCIOECONOMICS
 

The project area is located in western Carbon and eastern Sweetwater Counties in south central Wyoming 

(see Map 3.15-1). Five communities are likely to be primarily affected by natural gas development and 

production in the project area: Rawlins and Baggs in Carbon County and Wamsutter, Rock Springs, and 

Green River in Sweetwater County. The Town of Wamsutter is near the geographic center of the project 

area and is the only incorporated community within the project area. Although sharing some economic 

and social characteristics, each community is unique. 

The project area is about 40 miles across from east to west, and extends 20 to 25 miles north and up to 45 

miles south of I-80, being somewhat keyhole-shaped in general form (Map 3.15-1). I-80 bisects the 

project area along an east-to-west alignment. Along I-80, the eastern boundary of the project area is about 

25 miles west of Rawlins, the Carbon County seat. The western boundary of the project area is about 40 

miles east of Rock Springs in Sweetwater County. Approximately 80 percent of the total project area is 

located in Sweetwater County, and approximately 60 percent is within the “checkerboard” of federal/fee 

ownership pattern created by federal land grants to the railroad to promote development of the 

transcontinental railroad. 

The project area is sparsely populated; there are few permanently occupied residences outside of 

Wamsutter, although some ranch facilities and a few rural cabins and privately owned lots are occupied 

on a seasonal basis, the latter by the owners who park recreational vehicles (RVs) or camp. Green River, 

the Sweetwater County seat, lies about 50 miles west of the project area along I-80. 

The Carbon County town of Baggs lies about 8 miles southeast of the project area. 

Four other communities—the Carbon County towns of Dixon and Sinclair and the Sweetwater County 

towns of Bairoil and Superior—may also be minimally affected by the Proposed Action and alternatives. 

The size of these communities and their land ownership, lack of temporary housing, and/or distance from 

the project area indicate that substantial growth or other socioeconomic effects of the CD-C project would 

be unlikely. 

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No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

Map 3.15-1. CD-C project area and surrounding area 

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CHAPTER 3—AFFECTED ENVIRONMENT—SOCIOECONOMICS
 

3.15.1 Economic Conditions 

Economic conditions and trends for the study area were identified based on data from the U.S. Census 

Bureau, the U.S. Bureau of Economic Analysis, the U.S. Bureau of Labor Statistics, the Economic Profile 

System, from Headwaters Economics, available online at: <http://headwaterseconomics.org/tools/epshdt> and from other federal, state, and local sources as cited in the text. 

Local economic development and diversification efforts, coupled with expansion in mining, energy 

resources, and the local trade and services industries, brought about a period of economic stability 

through the 1990s with total employment fluctuating around 24,500 jobs (Figure 3.15-2). 

0 

5,000 

10,000 

15,000 

20,000 

25,000 

30,000 

35,000 

1970 1975 1980 1985 1990 1995 2000 2005 

Carbon Sweetwater 

Figure 3.15-2. Total full-time and part-time employment, 1970–2009 

Source: U.S. Bureau of Economic Analysis, 2011. 

In 2002/03, natural gas development again became a driving economic force in Sweetwater County, 

prompted by national energy policy, record-high energy prices, and other factors. From the 2002 level of 

23,989 jobs, over 3,400 jobs were added through 2005, with about 4,700 additional jobs added through 

2008. Available data indicate a net loss of more than 2,400 wage and salary jobs in 2009, or about 7.5 

percent of all such jobs, with a modest increase of approximately 500 jobs in 2010 (U.S. of Economic 

Analysis 2011, Wyoming Department of Employment 2011). 

In Carbon County, employment also climbed dramatically in the early 1970s, primarily due to energy 

resource development (coal, uranium, and oil and gas). The net gain of 6,437 jobs between 1970 and 1980 

represented a 90-percent increase in total employment. Like neighboring Sweetwater County, much of the 

gain in Carbon County was transitory as nearly 4,200 jobs were lost during the early/mid-1980s as the 

local coal and uranium industries both contracted. Thereafter the local economy remained relatively stable 

through 2004, at least in terms of employment. More than 200 new jobs were added between 2002 and 

2005, and nearly another 1,500 jobs added through 2008. Approximately 1,000 wage and salary jobs were 

lost in Carbon County in 2009, nearly 10 percent of all jobs in existence at the beginning of the economic 

recession in late 2007, with a further loss of about 200 jobs in 2010. Although the recession figured in 

some of the job cutbacks, a substantial number of the losses were associated with the scheduled 

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CHAPTER 3—AFFECTED ENVIRONMENT—SOCIOECONOMICS
 

completion of a major facility upgrade at the Sinclair Refinery (U.S. Bureau of Economic Analysis 2011, 

Wyoming Department of Employment 2011). 

Table 3.15-1 displays the current composition of the local economies in terms of covered employment. 

Mining, construction, and transportation/warehousing are the primary sectors in Sweetwater County’s 

economic base. In addition to oil and gas development, the mining industry includes two active coal 

mines and four trona mines. Trade, hospitality services, health care, education, and public-sector 

employment are also important local economic sectors. 

The mining sector has historically been important to Carbon County, but despite the level of recent and 

ongoing energy resource development in the region, the mining sector currently plays a more limited role 

in the Carbon County economy than that of its western neighbor. Pipeline and wind-energy facility 

construction, state government, health care, and the trade, accommodations, and food-service industries 

have also been important to the Carbon County economy. 

Table 3.15-1. Full-time and part-time covered employment, by industrial sector, 2009 

Industrial Sector Carbon County Sweetwater County 

Number % of Total Number % of Total 

Private 

Agriculture, Forestry, Fishing, and Hunting 198 2.7% 13 0.1% 

Mining 290 4.0% 5,446 22.3% 

Utilities 75 1.0% NR n/a 

Construction 533 7.3% 1,685 6.9% 

Manufacturing NR n/a 1,314 5.4% 

Wholesale Trade 62 0.8% 761 3.1% 

Retail Trade 759 10.4% 2,408 9.9% 

Transportation & Warehousing 235 3.2% 1,278 5.2% 

Information 82 1.1% 219 0.9% 

Finance & Insurance 149 2.0% 434 1.8% 

Real Estate & Rental & Leasing 83 1.1% 439 1.8% 

Professional & Technical Services 136 1.9% 532 2.2% 

Management of Companies and Enterprises NR n/a NR n/a 

Administrative and Waste Services 119 1.6% 418 1.7% 

Educational Services NR n/a 45 0.2% 

Health Care and Social Assistance 445 6.1% 1,019 4.2% 

Arts, Entertainment, and Recreation 79 1.1% 131 0.5% 

Accommodation and Food Services 859 11.8% 2,304 9.4% 

Other Services, Except Public Administration 154 2.1% 600 2.5%

 Subtotal private 4,715 64.5% 19,545 80.0% 

Government 2,134 29.2% 4,375 17.9% 

Total reported 6,849 68.8% 19,545 81.7% 

Not Reported (NR) due to disclosure guidelines 457 31.2% 4,375 18.29% 

TOTAL 7,308 100.0% 23,920 100.0% 

Source: Wyoming Department of Employment, 2010. 

Labor Market Conditions 

Local labor markets are reflective of the underlying economic and demographic conditions. From 1990 

through 2002, the pool of residents employed or actively seeking work remained relatively steady in 

Sweetwater County. Fueled by expanded economic opportunities associated primarily with natural gas 

development, migration, and increases in labor-force participation among residents, the local labor force 

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has since expanded by almost 3,700 individuals, or 19 percent in five years. In Carbon County, the local 

labor force underwent a slow but protracted decline from 1990 through 2004, shrinking by nearly 1,200 

individuals or 14 percent. This period is also characterized by steady out-migration of former residents. 

Labor demand tied largely to the increase in natural gas development spawned a reversal in trends, 

attracting more than 700 current and immigrating individuals into the Carbon County work force between 

2004 and 2008. During the same period, the resident labor force in Sweetwater County expanded by more 

than 3,200 individuals, approximately 14 percent (Figure 3.15-3). More recently, weaker labor demand 

brought about by the recession and associated impacts on natural gas development in the region resulted 

in labor force contractions. 

0 

5,000 

10,000 

15,000 

20,000 

25,000 

30,000 

1990 1995 2000 2005 2010 

Carbon Sweetwater 

Figure 3.15-3. Local resident labor force: 1990–2010 

Source: U.S. Bureau of Labor Statistics, 2011. 

Unemployment in the region since 1990 had generally been between 5.0 and 6.5 percent, on par with or 

slightly above the statewide average (Figure 3.15-4). Migration and commuting play important roles in 

moderating local unemployment rates. Local unemployment rates dropped sharply in 2000, with a more 

protracted decline between 2004 and 2008. During the recent expansion, labor markets were tight across 

the state due to the high demand for labor associated with ongoing energy development. In Sweetwater 

County average annual unemployment dropped to a record low of 2.3 percent in 2007, representing fewer 

than 600 individuals unable to find work, or temporarily between positions. Carbon County also had 

record low unemployment in 2007, averaging just over 250 unemployed, representing 3.0 percent of the 

local labor force (U.S. Bureau of Labor Statistics 2010). The effective unemployment rate was likely even 

lower as the estimates of the local labor force used to calculate unemployment rates may not capture all 

non-resident laborers working in the area but living in motels, RV parks, and other temporary housing. 

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0.0% 

1.0% 

2.0% 

3.0% 

4.0% 

5.0% 

6.0% 

7.0% 

8.0% 

1990 1995 2000 2005 2010 

Carbon Sweetwater 

Figure 3.15-4. Local Unemployment Rates (average annual): 1990–2010 

Source: U.S. Bureau of Labor Statistics, 2011. 

The tight labor market was reflected in across-the-board labor shortages in Carbon and Sweetwater 

counties. All economic sectors appear to be affected by the high demand for workers. The labor shortage 

resulted in higher wages, bonuses, and per-diem payments in the natural gas industry. High wages in the 

natural gas industry resulted in job shifts and worker loss in other sectors of the economy, creating 

upward pressure on wages for employees across the private and public sectors. Even with the increase in 

wages, local and state government and private businesses were frequently short-staffed and experienced 

high employee turnover during 2007 and 2008 (Derragon 2008, Rader 2007, Spicer 2007). Shortages of 

affordable housing in Carbon and Sweetwater counties (discussed in Section 3.15.5) impeded recruitment 

of non-local workers, who frequently had difficulty competing for housing with higher-paid gas-industry 

workers. Natural gas service companies were required to develop or contract for temporary housing for 

employees, many of whom were rotated in and out of the area on a temporary basis. 

Employers in other sectors of the economy were in some cases constrained from expanding their business 

because of labor shortages. Some retail and service businesses had to limit business hours and, in at least 

one case, temporarily ceased operating because of their inability to attract or retain employees. 

A slowdown in the pace of natural gas development, combined with the effects of the recession and the 

housing mortgage crisis, resulted in substantial economic dislocation and job losses in the region. 

Unemployment and unemployment rates more than doubled between 2008 and early 2010, peaking at 7.3 

percent and 564 unemployed in Carbon County. Peak unemployment in Sweetwater County topped 2,000 

individuals in early 2010, representing 8.8 percent of the labor force. More recently, local unemployment 

has declined, to 5.3 percent and 392 unemployed in Carbon County and 5.6 percent and 1,345 

unemployed in Sweetwater County in March 2011 (U.S. Bureau of Labor Statistics 2011). 

Sections 3.3 through 3.5 of the Baseline STR describe recent trends in key sectors of the Carbon and 

Sweetwater County economies including agriculture; minerals; and tourism, travel, and outdoor 

recreation. Section 3.6 of the STR discusses energy development effects on retirement migration and nonlocation-dependent businesses. Key findings of these sections are discussed below. 

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Agriculture 

Farm employment has been trending downward in Carbon and Sweetwater counties since 1970. Carbon 

County farm employment decreased from 741 in 1970 to 564 in 2000, a 23-percent decrease over the two 

decades. Farm employment continues to trend downward in Carbon County, falling below 400 in 2005 

and to 369 in 2009. 

Sweetwater County farm employment decreased from 552 to 201, a 63.5-percent decrease in the same 

period (Headwaters Economics 2007a and 2007 b). Farm employment has since trended upward, to 266 

in 2009. 

A total of 287 individual farms and ranches, operating on nearly 2.2 million acres of land, were recorded 

in Carbon County in the 2007 Census of Agriculture. Both totals represent slight declines relative to the 

corresponding totals tallied in the 2002 Census of Agriculture. In 2007, a total of 244 farms and ranches, 

operating nearly 1.5 million acres of land, were tallied in Sweetwater County (National Agricultural 

Statistics Service 2009). 

In 2008, local ranches and farms in the two counties reported total cash receipts of $60.5 million in 

agricultural products, with livestock sales the primary source of agricultural revenue in both counties. 

Gross annual agricultural sales in Carbon County in 2008 were nearly four times the level in Sweetwater 

County during that year. Cash receipts from livestock and crop sales in Carbon County declined by 

approximately 20 percent over the past five years, but increased slightly in Sweetwater County (U.S. 

Bureau of Economic Analysis 2010). 

Minerals 

Mining employment in both counties reflect the period of intensive energy and minerals development in 

the late 1970s and early 1980s and the ensuing slowdown as world energy prices fell. Current and 

historical mining activity in the study area includes trona mining in Sweetwater County, and coal, 

uranium mining and oil and natural gas production in both counties. Mining employment in Carbon 

County peaked at 3,563 in 1980, declined to a low of 180 in 2003 and subsequently increased to 621 in 

2008. Sweetwater County mining employment declined from its peak of 7,811 in 1981 to a 2000 low of 

3,736,11 climbing to 6,717 in 2008 (U.S. Bureau of Economic Analysis 2010). Recession related job 

losses in mining from 2008 to 2010 are estimated at about 200 in Carbon County and 500 to 600 in 

Sweetwater County (Wyoming Department of Employment, 2011). 

Assessing recent mining-sector employment in the study area is complicated by the nature of employment 

practices in the natural gas industry. Acute labor and housing shortages within the study area during the 

boom years, coupled with the mobile nature of many natural gas drilling and service company operations, 

hampered the reporting and tracking of natural gas industry employees. Shortages of local labor resulted 

in many workers relocating to the study area on a temporary basis, working at job sites located in several 

counties while staying in temporary lodging near the work site, and then returning home for extended 

periods. Consequently their employment may not be recorded in the county where they are actually 

working, or if their employer is located outside the study area, these workers may not be recorded within 

the affected counties at all. 

Oil and natural gas exploration and production have been important but volatile elements of the Carbon 

and Sweetwater County economies for well over 30 years. According to the Wyoming Oil and Gas 

Conservation Commission (WOGCC), Carbon County natural gas production increased from 75,851 

million cubic feet (MMcf) in 1995 to 128,395 MMcf in 2009, or 69 percent. Production then declined by 

4 percent, to 122,755 MMcf, in 2010. Carbon County oil production approached 1.82 million barrels 

(bbls) in 2009, about 38 percent higher than the 1995 level of 1.3 million bbls, but then declined to 1.59 

11 Mining employment for 2001 through 2004 was not reported by the U.S. Bureau of Economic Analysis due to disclosure 

restrictions. Mining employment may have fallen even lower in 2001; however the current natural gas expansion began in 2002. 

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CHAPTER 3—AFFECTED ENVIRONMENT—SOCIOECONOMICS
 

million bbls in 2010. During 2007, there were 1,620 total producing oil and gas wells in Carbon County, 

and the county produced 5.9 percent of total gas produced in Wyoming and 3.4 percent of total oil. By 

2010, the number of producing wells had climbed to 1,791, with another 425 wells idle. Annual oil 

production had declined to about 1.6 million bbls. The production declines from 2009 to 2010 occurred in 

part due to the sharp decline in new wells completed in 2009 (WOGCC 2011b). 

Annual natural gas production in Sweetwater County decreased from 238,000 MMcf in 1995 to 192,000 

MMcf in 2000, but subsequently increased to 235,316 MMcf in 2007. Sweetwater County production 

accounted for about 12 percent of all natural gas produced in Wyoming and about 11 percent of all oil 

during 2007. The county had 3,234 producing oil and gas wells in 2010, compared to 3,089 in 2007. Total 

production of 240,144 MMcf of natural gas and 5.35 million bbls of oil occurred in Sweetwater County in 

2010 (WOGCC 2011b). 

The Sweetwater County economy is affected by oil and gas activity occurring beyond its borders. Over 

the last decade, Rock Springs has emerged as a natural gas service center for southwestern Wyoming. A 

number of oil and gas service companies that service the entire region have established major service 

centers in the Rock Springs area. Halliburton, Schlumberger, and BJ Services have all established major 

yards in the Rock Springs area and, according to the Sweetwater Economic Development Authority, 

employed a total of 1,360 employees in early 2007 (SWEDA 2007a). 

Historically, natural gas sales prices in Wyoming were substantially lower than prices received for gas in 

other markets. This “price differential,” resulting from constraints in natural gas transmission capacity to 

markets outside of Wyoming, was usually expressed as the difference between average Wyoming sales 

prices, e.g., prices at the Opal Hub, Cheyenne Hub, or some combination of the two, and those at 

Louisiana’s Henry Hub. The Henry Hub is one of several reference pricing points for natural gas. 

Between January 2000 and December 2007, the price differential between Wyoming gas and national 

averages ranged from just a few cents to $5.00 during the summer of 2007 (Wyoming Pipeline Authority 

2008). The price differential effect fluctuated based on such factors as gas supply in Wyoming and 

weather and other demand factors. 

This price differential is important for state and local government because it affects revenues from ad 

valorem and severance taxes and royalty payments and also affects gas company development decisions. 

Extension of the Rockies Express Pipeline to Midwestern markets in 2008 and 2009 saw some 

moderation of the price differential, and the completion of the Bison pipeline in northeastern Wyoming in 

early 2011 also had an effect. Further narrowing of the price differential is expected as additional gas 

transmission capacity comes online: the Ruby pipeline, which was completed in mid-2011 and transports 

gas from the Opal hub to Oregon; and two expansions of the Kern River pipeline, also originating in 

southwestern Wyoming, which were completed in April 2010 and October 2011 (Kern River 2012, Ruby 

Pipeline LLC 2011, Wyoming Pipeline Authority 2010). 

Travel and Tourism, Including Outdoor Recreation 

Travel and tourism in the region, including non-residents engaged in outdoor recreation locally, generate 

important contributions in the local economy. In addition to the economic benefits, outdoor recreation, 

including hunting and fishing, is also an important contributor to the quality of life of many local 

residents. 

Much of the tourism and travel in Carbon and Sweetwater counties is traffic passing through the region 

on I-80 which supports the lodging, dining, and entertainment sectors. These sectors also benefit from 

energy workers residing in the area on a temporary basis. An economic analysis of travel in Wyoming in 

2006 estimated annual tourism and travel spending by non-residents of $166.7 million and $142.6 million 

in Sweetwater and Carbon counties, respectively. That spending supported an estimated 2,020 jobs in 

Sweetwater County and 1,560 jobs in Carbon County (Dean Runyan Associates 2007). Travel and 

tourism were also affected adversely by the economic recession. In 2009 estimated annual travel spending 

by non-residents in Sweetwater County was more than $22 million lower than in 2006, with a 

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corresponding decline of 330 travel/tourism-related jobs. In Carbon County, the corresponding changes 

were $12.6 million in lower spending and a loss of 300 jobs (Dean Runyan 2010). 

Analysis of the seasonal variations in employment in the accommodations and food service sectors, and 

the comparative growth in spending in recent years, indicate that a noteworthy portion of those totals 

reflect travel in the I-80 corridor and the impacts of energy workers residing temporarily in the 

communities, rather than more traditional destination-type tourism.12 Local observations about the 

tourism and recreation economy in Carbon and Sweetwater counties help illuminate the findings of the 

Dean Runyon studies. Sweetwater and Carbon counties do not have major tourism attractions such as 

Yellowstone and Grand Teton National Parks that attract large numbers of destination visitors. Rather, the 

visitor economy in Carbon and Sweetwater counties is based on outdoor recreation, including hunting and 

fishing by non-residents, and non-local participation in local events such as historic/cultural celebrations, 

competitions, conventions, and conferences (Radar 2007, Spicer 2008). 

The strong pace of natural gas development in Carbon and Sweetwater counties between 2000 and 2008 

had both beneficial and adverse effects on tourism and recreation-related businesses. In addition to the 

general across-the-board increase in business, the beneficial effects of the gas expansion included 

increases in customers and occupancy rates during the traditional winter and spring off-seasons, which 

increased the year-round profitability of businesses catering to travelers. High demand also resulted in an 

increase in the number of lodging and dining establishments, which in turn increased the lodging and 

dining base for tourism and recreation visitors. High occupancy rates for lodging establishments also 

resulted in a dramatic increase in lodging tax revenues; lodging tax revenues increased from $110,000 to 

$362,000 between fiscal year 2002 and fiscal year 2008 in Rawlins, and from $254,000 to $615,000 in 

Rock Springs during the same period. Local tourism and recreation organizations have used these 

revenues to develop promotional materials and to promote events that bring visitors to the area and 

increase the average length of stay. Reductions in lodging tax revenues in the ensuing two years, to 

$278,000 (-23 percent) in Carbon County and $422,000 (-31 percent) in Sweetwater County, provide 

another measure of the recessionary effects on natural gas development and tourism in the area 

(Wyoming Dept. of Administration and Information, various years). 

Adverse effects of natural gas and other energy development on the travel and tourism industry included 

the high energy-worker occupancy rates in lodging establishments, particularly during summer months, 

which reduced lodging availability for recreationists, event attendees, and travelers on I-80. Travel and 

tourism businesses, like most businesses in the study area, reported difficulty in recruiting and retaining 

employees during the boom years (Radar 2007, Spicer 2008). 

Energy Development Effects on Retirement Migration and Non-Location-Dependent 

Businesses 

Many communities view local economic diversification as a goal to help achieve economic stability. 

Recently, some groups and organizations have highlighted the importance of retirees and other sources of 

non-labor income, service and professional occupations, and non-location-dependent businesses as key to 

economic diversification in western communities. A number of recent studies espouse the potential role 

of amenity values, including those on public lands, in attracting retirement migration and non-locationdependent businesses to rural communities in the West and serving as a foundation of overall economic 

development strategy for rural western communities. Public comments during the scoping for this EIS 

and on other natural-resource-development actions in the region have expressed concern about the 

potential effects of energy development on the amenity values of public lands and the resultant 

12 “Travel” for the purposes of that analysis includes both business and pleasure travel by residents and non-residents that was 

more than 50 miles from the traveler’s home. In the study area this would include spending by all travelers on I-80, as well as that 

by non-resident workers employed in the area on an extended basis but staying in local motels, hotels, and campgrounds. 

Although not explicitly addressed in the Runyan Report, the spending estimates likely capture some spending by non-local 

hunters and anglers. 

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CHAPTER 3—AFFECTED ENVIRONMENT—SOCIOECONOMICS
 

detrimental effects on retirement migration, non-location-specific business attraction, and 

tourism/recreation visitation. Adverse effects on other sectors of the economy such as recreation and 

grazing, effects on environmental amenities, and general boom conditions such as scarcity and high cost 

of housing and labor shortages are also viewed as having the potential to dampen economic diversity in 

communities within the study area. 

Section 3.6 of the Baseline STR examines retiree migration, non-location-specific business attraction, and 

tourism/recreation in Carbon and Sweetwater counties using an analytical framework combining 

comparative cross-sectional and time series analysis involving 198 rural counties in six western states.13,14 

Among the findings of this analysis are the following: 

Retirees 

 Per-capita personal income growth in Carbon and Sweetwater Counties outpaced that of the 198 

rural western counties, climbing to 119 percent of the average in Carbon County in 2005; and from 

126 percent to 146 percent of the overall average between 1990 and 2005. 

	 Dividends, interest, and rent (DIR) and personal current transfers (PCT)15 are two measures of nonearned income typically correlated with retirees. The growth in per-capita DIR in Carbon and 

Sweetwater Counties between 1990 and 2005 substantially exceeded the rural western county 

average and the growth in PCT generally paralleled the rural average during that period. The latter 

is noteworthy given the high labor force participation in Sweetwater County and the large nonworking population in Carbon County associated with the Wyoming State Penitentiary, suggesting 

that energy development did not prompt any relatively disproportionate out-migration of retirees or 

deter in-migration of new retirees. 

	 Anecdotal information and census data suggest that absent energy development, relatively few 

retirees would choose to relocate to the study area parts of Carbon and Sweetwater County from 

outside these counties. Some retirees move from smaller communities and ranches within these 

counties to Rawlins, Rock Springs, or Green River, and some retirees have accompanied family 

members relocating for employment purposes, but most of the growth in the retirement sector in 

these communities appears to be associated with the aging of the resident workforce (Ducker 2007, 

Archer, 2007). 

These trends suggest little or no adverse effects of energy development with respect to influencing 

retirement income or migration within the study area when compared to all rural counties. 

Non-Location-Dependent Businesses 

 Carbon County has experienced more rapid growth in the number of non-farm proprietors and such 

proprietors account for a larger share of employment when compared to the peer group of all rural 

counties. Because of the presence of large trona and coal mines, soda-ash and fertilizer 

manufacturing plants, and large electric-power generating plants, Sweetwater County has had 

relatively fewer proprietors and has seen lower growth in the number of non-farm proprietors, a 

substantially lower share of employment accounted for by such proprietors. Also, the recent location 

of large oil and gas service companies in Rock Springs would contribute to the latter. 

	 Average annual income for non-farm proprietors in Carbon County, historically lower than the peer 

group, is now on par. However, the average income for non-farm proprietors in Sweetwater County 

is more than twice the average for all rural counties, and even higher than the averages for the urban 

and resort counties. The differences may indicate a higher tendency for part-time proprietors in rural 

13 There are 249 counties in the six states. Of these, 198 were considered rural for the analysis; 43 were excluded as urban counties 

and eight were excluded as winter-resort communities that are fundamentally atypical from other counties in the region. 

14 This analysis has not been revised since the original STR. 

15 Personal current transfers (PCT) include unemployment, income maintenance, and retirement receipts. 

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areas as compared to Sweetwater County, or differences in the industries and activities in which 

non-farm proprietors are active in Sweetwater County. 

While the non-farm proprietor data reveal differences between Carbon and Sweetwater counties as 

compared to the peer group, they are inconclusive with respect to whether or not energy development 

stimulates or adversely affects the recruitment or operations of location-independent non-farm 

proprietors. 

Influence of Environmental Amenities 

The project area is located some distance from the major population centers in both counties and has been 

the site of ongoing oil and gas development for over 40 years. Much of the project area has been affected 

by development, adversely affecting some outdoor amenities including wildlife and wildlife habitat, 

scenic vistas, and areas that provide opportunities for solitude. 

Although no major regional scenic and recreation attractions are located within the project area, scoping 

comments indicate that several features within the area are important to some residents and non-residents 

alike, including a sage-grouse lek complex southeast of Creston, a small portion of the Red Lake Dunes 

Citizens’ Proposed Wilderness located in the northwestern part of the project area, and the Chain Lakes 

WHMA located in the northeast portion of the project area. The importance of these and other 

environmental amenities located within and adjacent to the project area for attraction of retirees and nonlocation-dependent businesses to communities in the study area is not known. However, given the number 

of more widely known scenic and recreation attractions within the region, the distance to major 

communities, and the historic level of gas development activity and disturbance, the importance is likely 

low. It is not known if existing development within the project area adds to the existing cumulative effects 

on environmental amenities within the region and to the way the region is viewed by potentially 

relocating retirees and non-location-dependent businesses. 

3.15.2 Population and Demographics 

Figure 3.15-5 displays population statistics for Carbon and Sweetwater counties between 1970 and 2010. 

These statistics show the population effects of the mining and energy expansion, which began in the early 

1970s, peaked in the early 1980s in both counties, and then began to decline. Carbon County population 

increased 69 percent between 1970 and 1982 and Sweetwater County population increased 149 percent 

during that period. Sweetwater County experienced a brief resurgence of the boom in the mid-1980s 

during construction of the Exxon La Barge gas-sweetening plant, expansion of the Jim Bridger power 

plant, construction of the Chevron Phosphate plant east of Rock Springs, and expansion of Western 

Wyoming College. 

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0 

5,000 

10,000 

15,000 

20,000 

25,000 

30,000 

35,000 

40,000 

45,000 

50,000 

1970 1975 1980 1985 1990 1995 2000 2005 2010 

Carbon Sweetwater 

Figure 3.15-5. Population, Carbon and Sweetwater Counties: 1970–2010 

Compiled from Wyoming Department of Administration and Information, Division of Economic Analysis and U.S. Census 

Bureau reports. 1970, 1980, 1990, 2000 and 2010 populations are Census data; other years are population estimates 

produced by U.S. Census Bureau. 

Source: U.S. Census Bureau, 2010xx; U.S. Census Bureau, 2011xx and above. 

Sweetwater County’s population climbed moderately in the 1990s in conjunction with a number of 

construction projects and ongoing maintenance of mining and energy facilities. The county’s recent 

natural gas-related growth surge began in 2004, though population in 2010 was still about 4 percent 

below the 1982 peak, according to 2010 Census counts. Carbon County continued its downward trend for 

much of the 1990s, and has fluctuated between 15,000 and 16,000 over the past decade. 

Table 3.15-2 displays recent population estimates for selected communities in Carbon and Sweetwater 

counties. As shown, most of the communities within the study area experienced substantial growth during 

the past decade. Although Rawlins grew by 9 percent between 2005 and 2010, the net gain over the last 

decade was 3 percent as a result of population loss earlier in the decade. 

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CHAPTER 3—AFFECTED ENVIRONMENT—SOCIOECONOMICS
 

Table 3.15-2. Population of selected Carbon and Sweetwater County communities: 2000–2010 

2000 2005 2006 2007 2008 2009 2010 

Change 

2000­

2010 

% Chg 

Carbon County 

Rawlins 8,969 8,503 8,534 8,651 8,723 8,791 9,259 290 3% 

Sinclair 421 399 399 403 404 406 433 12 3% 

Baggs 348 347 363 388 403 423 440 92 26% 

Dixon 79 79 79 81 81 82 97 18 23% 

Balance of 

County 5,822 5,723 5,790 5,874 5,953 6,018 5,626 -196 -3%

 County total 15,639 15,051 15,165 15,397 15,564 15,720 15,855 216 1% 

Sweetwater County 

Rock Springs 18,589 18,474 18,956 19,629 20,160 20,905 23,036 4,447 24% 

Green River 11,806 11,528 11,702 12,047 12,115 12,411 12,515 709 6% 

Wamsutter 260 261 262 270 272 310 451 191 73% 

Bairoil 97 95 95 97 96 98 106 9 9% 

Superior 243 235 235 240 237 242 336 93 38% 

Balance of 

County 6,618 6,738 6,767 7,037 7,062 7,260 7,362 744 11%

 County total 37,613 37,331 38,017 39,320 39,942 41,226 43,806 6,193 16% 

Sources: U.S. Census Bureau, 2010 and 2011. 

Sweetwater and Carbon County officials believe that U.S. Census population estimates do not fully 

reflect the population growth during the energy expansion years. The Sweetwater Economic Development 

Authority (SWEDA) developed population estimates for the county and its incorporated municipalities, 

based on residential electric accounts and an average persons-per-household estimate (2.58) obtained 

from the Wyoming Division of Economic Analysis. The SWEDA Sweetwater County population 

estimate of 48,000 for 2007 was over 20 percent higher than the 2007 Census estimate and as much as 

128 percent higher for Wamsutter (SWEDA 2007b). Although they did not prepare their own estimates, 

Rawlins and Baggs officials also believed that the U.S. Census Bureau estimates during the 2006–2008 

period substantially underestimated population in their communities, based on increases in utility hookups and building permits (Derragon 2008, Corners 2007). 

The components of population-change statistics show a net out-migration of approximately 400 residents 

from Carbon County between 2000 and 2009, with a net in-migration of approximately 300 residents to 

Sweetwater County during the same period (U.S. Census Bureau 2010). These statistics may not fully 

capture the many temporary workers in both counties that accompanied the surge in natural gas 

development. 

Based on the 2010 Census, residents of Carbon County tended to be somewhat older than those in 

Sweetwater County, but were similar in age to the population of the State of Wyoming and the United 

States overall. In Carbon County, nearly one of eight residents was 65 years or older, as compared to 

about one in 12 in Sweetwater County. The median age has stayed about the same in the last ten years in 

Carbon County (38.9 years), while the median age in Sweetwater County has dropped from 34.2 to 32.8 

(U.S. Census Bureau 2011). 

The largest shares of population in both counties are working age adults aged 18 to 64 years. In Carbon 

County, the number of persons aged 18 to 64 increased just slightly between 2000 and 2010, accounting 

for 63.5 percent of all residents in 2010. In Sweetwater County, the number of persons aged 18 to 64 

increased by more than 4,500 individuals (19.2 percent) from 2000 to 2010. The number of young 

persons under age 17 and the number of persons 65 years and older in Sweetwater County also increased. 

Increases in the number of working-age persons in these counties can be correlated to recent increases in 

jobs, particularly in the mining sector, which attracts a high portion of working adults. Also consistent 

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with this pattern is the number of natural gas-related jobs attracting younger male workers who are 

unmarried or married but not accompanied by school-age children. In addition, the number of miningsector jobs has increased noticeably in Sweetwater compared to Carbon County, which is also reflected in 

the major increase in working-age adults in Sweetwater County as compared to Carbon County. 

The racial and ethnic compositions of the local populations reflect the influences of historical settlement 

patterns and economic factors, including substantial labor migration in response to the relative abundance 

of economic opportunity. According to the 2010 Census, Carbon County’s resident population was 79.8 

percent white and not Hispanic or Latino, with 20.2 percent of the population being made up of persons of 

other races, multiple races, and/or of Hispanic or Latino ethnicity. The minority population in Carbon 

County increased from 17.6 percent in 2000 to 20.2 percent in 2010. Sweetwater County has a larger 

share of the population that is white and not Hispanic or Latino, with 80.9 percent of the population as 

non-Hispanic white and 19.1 percent of the population being made up of persons of other races, multiple 

races, and/or Hispanic or Latino ethnicity. Though the percentage share of racial and ethnic minorities in 

these two counties is higher than for the State of Wyoming as a whole, it is much lower than that for the 

United States. The minority population in Sweetwater County has increased from 13.1 percent in 2000 to 

19.1 percent in 2010. The largest racial and ethnic minority group in both counties is Hispanic and Latino, 

making up 16.8 percent of the Carbon County population and 15.3 percent of the Sweetwater County 

population. 

The Economic Analysis Division of the Wyoming Department of Administration and Information 

(WEAD) prepares population forecasts for Wyoming and its counties and municipalities. The current 

forecasts, which pre-date the results of the 2010 Census, anticipated Carbon County’s population 

increasing by about 5 percent over the next ten years, from 16,350 in 2011 to 17,230 in 2020 and then 

decreasing slightly to 17,140 by 2025. The forecasts show Sweetwater County population trending 

upward, increasing from 42,420 in 2011 to 47,220 in 2025—an increase of 11 percent during the 15-year 

period (WEAD 2008). 

3.15.3 Housing 

This section provides information about conventional and temporary housing resources in the study area. 

A shortage of housing during the boom period, particularly affordable housing, is a key issue routinely 

cited by the local officials, service administrators, and local residents interviewed for this assessment. 

Table 3.15-3 displays housing information from the 2010 census. 

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Table 3.15-3. 2010 Census housing status by county and community 

Carbon 

County Rawlins Baggs Sweetwater 

County 

Rock 

Springs 

Green 

River Wamsutter 

Total Housing Units 

2000 8,307 3,860 197 15,921 8,359 4,426 148 

2010 8,576 3,960 223 18,735 10,070 5,002 286 

 Change (%) 3.0% 3.0% 13.0% 18.0% 20.0% 13.0% 93.0% 

Occupancy Data, 2010 

Total Occupied Units 6,388 3,443 183 16,475 8,762 4,642 189 

Home-owner Occupied 

Units 

4,552 2,346 122 11,872 5,952 3,454 98 

Renter-Occupied Units 1,836 1,097 61 4,603 2,810 1,188 91 

Total Vacant Units 2,188 517 40 2,260 1,308 360 97 

Home-owner Vacancy 

Rate 

3.4% 3.0% 2.4% 2.8% 3.2% 2.5% 3.8% 

Rental Vacancy Rate 16.5% 16.6% 17.1% 16.8% 19.1% 11.0% 17.1% 

Vacant for Seasonal Use 1,070 36 6 295 79 35 31 

Source: U.S. Census Bureau, Census 2000; US Census Bureau, 2010. 

3.15.3.1 Carbon County 

According to 2010 Census housing counts, total Carbon County housing units increased from 8,307 units 

to 8,576 units, or about 3 percent over the decade. The number of total housing units increased between 

2000 and 2010 in every community in the study area except Dixon, which lost three units. 

Carbon County’s housing stock expanded dramatically in the late 1970s and early 1980s in conjunction 

with the previous economic expansion. Given the subsequent contraction, few permits for new residential 

construction were issued until a brief surge in residential permits occurred in the mid to late 1990s. Strong 

housing demand associated with the more recent local economic expansion prompted considerable new 

residential construction over the past decade, particularly between 2004 and 2008. According to the 

Wyoming Housing Database Partnership (WHDP), Carbon County issued 334 residential building 

permits during the five years 2004 through 2008. Building permit applications fell sharply in Carbon 

County during 2009 to 24 units, just 36 percent of the annual average for the previous five years, and to 

18 in 2010 (WHDP 2011 and U.S. Census Bureau 2011). It is likely that the recession resulted in the 

cancellation of construction of some units that had been planned and for which building permits had been 

issued. 

In recent years, several large, temporary living facilities were built for workers near the gas fields in 

Carbon County. A temporary living facility was developed along WY 789 north of Dad for Devon Energy 

which currently houses about 80 workers and can be expanded to house a total of 150 workers. A second 

camp has been developed along WY 789 for Nabors Drilling and a third camp was also proposed. 

City of Rawlins 

The 2010 Census tallied 3,960 total housing units in Rawlins in 2010, a 3 percent increase over the 

housing inventory in 2000. The net change understates the amount of traditional housing development 

that occurred in the city because it reflects both demolitions (Mika 2007) and decreases in the number of 

mobile homes during the past decade. Of the 2010 total of 3,443 occupied units, about 59 percent were 

owner-occupied and the remaining 41 percent were renter-occupied. 

Information about housing conditions in Rawlins during the recent natural gas expansion was obtained 

from the 2007 Rawlins Housing Assessment (Kirkham & Associates LLC 2007). The housing assessment 

was intended to assist city officials, community leaders, and developers in planning for infrastructure and 

housing development in response to the growth that was occurring and anticipated at that time. 

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Between 2001 and 2007, 106 single-family residential building permits and no multi-family permits were 

issued in Rawlins. Rawlins has 11 apartment complexes with a total of 439 units. The newest of these is 

an 85-unit complex built in 1997. The 2007 Housing Assessment estimated that the city needed 170 

additional multi-family units, of which 100 should be rent-assisted. 

At the time of the 2007 housing study, Rawlins had 19 mobile-home parks. In recent years, three mobilehome parks with a total of 146 pads were converted to lot ownership where the mobile-home owner also 

owns the lot. The 2007 Housing Assessment projected demand for three new mobile-home parks in 

Rawlins by 2010. During 2010 Rawlins had 16 mobile home parks with 639 pads (MHPS 2010). 

Housing availability in Rawlins has been volatile in recent years. The 2007 Housing Assessment 

estimated rental housing vacancies at less than 1 percent in December 2006. According to that 

assessment, there were virtually no apartment vacancies in mid 2007 and most complexes had waiting 

lists. Rental housing and apartment vacancies increased during 2008 and early 2009 due in part to the 

reduction in the construction work force at the Sinclair refinery (Mika 2009). The WHDP estimated 

overall vacancy rates at 16 percent during the second half of 2009 (WHDP 2010). 

According to the Carbon County Visitors Council (CCVC) Rawlins has 23 motels with a total of over 

1,252 rooms (CCVC 2010). Some motels offer weekly or monthly rates and typically host energy 

industry and construction workers. Rawlins also has 3 recreational vehicle parks with a total of 303 pads, 

although one RV park is not winterized (Stolns 2010). The CCVC conducted an informal telephone 

survey of motels and RV parks during August 2010. The CCVC reported that the newer, nationally 

affiliated motels in Rawlins averaged 95 to 98 percent occupancy, while the older and smaller motels, 

which were more likely to accommodate construction and gas-field workers on a weekly or monthly 

basis, averaged 75 to 80 percent occupancy. Local RV parks averaged 80 to 85 percent occupancy 

(CCVC 2010). 

Baggs 

Total housing units in Baggs grew from 197 to 233 units between 2000 and 2010, an increase of 13 

percent. During that period, Baggs approved a 16-lot subdivision and a 6-lot subdivision. Most housing in 

the Baggs area is manufactured housing and mobile homes (Corners 2007). There is little available rental 

housing and rents have increased substantially in recent years. 

In the Baggs area, temporary housing resources include two motels with a total of 64 rooms and a 26­

space mobile home park equipped to accommodate RVs and mobile homes. Within the park there are 

several mobile homes for rent, but these are rarely vacant. There are also two RV parks on WY 789 north 

of town (CCVC 2010). 

3.15.3.2 Sweetwater County 

According to the 2010 Census, total housing units in Sweetwater County increased from 15,921 to 

18,735, an 18 percent increase over the preceding decade. Much of that growth occurred between 2004 

and 2008, when Sweetwater County issued 2,150 building permits (WEAD 2011). Sweetwater County 

issued a total of 2,651 building permits from 2001 to 2010. Of those, 70 percent were issued during the 

2003 to 2008 period. Building permits fell from the 2008 level of 321 to 160 in 2009, but have increased 

to 213 in 2010. (Kot 2011). 

As with Carbon County, the effects of the natural gas-related economic expansion and contraction are 

evident in the housing statistics. The WHDP estimated rental housing vacancy rates below 1 percent in 

Sweetwater County in December 2006. The tight housing market was reflected in rising rents; the average 

apartment-rental rate rising from $512 in the second quarter of 2005 to $684 in the second quarter of 

2006, an increase of almost 34 percent in one year. Average rental rates of detached single-family homes 

increased approximately 21 percent during the same period while the average monthly rent for mobile 

homes increased almost 13 percent and the average monthly rent for a mobile home lot rose by 11 

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percent. As elsewhere in southwestern Wyoming, the shortage and high cost of rental housing was a 

constraining factor on employee relocation and on the ability of people on low or fixed incomes to 

acquire and retain rental housing. 

During 2009 and 2010, rental vacancy rates in Sweetwater County rose to between 5 and 7 percent. 

Average monthly apartment rental costs fell from the second quarter 2009 high of $779 to $691 per 

month in the second quarter of 2010, a decrease of 11 percent. Monthly rates for rental housing fell by 

almost 18 percent between fourth quarter 2008 and fourth quarter 2010 (WHDP 2010). 

During the height of the boom, ESS Support Services, under contract to BP, developed a 250-bed 

temporary living facility with food service, housekeeping, and recreation facilities just north of 

Wamsutter. The Wamsutter Base Camp was open to both BP employees and gas-field contractors. The 

facility was permitted for 500 beds, providing flexibility to expand as demand emerged (Van Rensburg 

2007). As yet another reflection of the curtailment in development activity during the recession, that 

facility has now been closed and removed from the site. 

City of Rock Springs 

Rock Springs has seen dramatic changes in housing conditions in recent years, driven primarily by the 

increase in demand associated with natural gas development. The 2010 Census counted 10,070 housing 

units in Rock Springs, 20 percent more than the 2000 Census count of 8,359 units. 

The City of Rock Springs issued a Final Housing Plan (Housing Plan) in September 2007 to inform the 

community about anticipated housing needs and potential housing development opportunities in the city 

(City of Rock Springs Housing and Community Development 2007). The Housing Plan identified 1,560 

acres of land used for residential purposes and 8,899 housing units located within the city during January 

of 2007. Table 3.15-4 displays the distribution of housing, by unit type, within the city at that time. 

Single-family units were the predominant form of housing with 60 percent of all housing being singlefamily detached units. 

Table 3.15-4. Rock Springs total housing units by housing type: January 2007 

Housing Unit Type # Housing Units Percent of Total 

Detached single-family 5,319 60 

Attached single-family 886 10 

Mobile homes 1,447 16 

Apartments 1,247 14 

Total 8,899 100 

Source: City of Rock Springs Housing and Community Development 2007. 

The number of housing units in Rock Springs grew by about 8 percent, or 685 units, between 2004 and 

January 2007 according to the Housing Plan. This generally coincides with the period of intensified 

natural gas development in the region. 

The City approved 33 new subdivisions between January 2004 and May of 2007. Of those, 25 

subdivisions were for residential development with the potential to create over 2,000 residential lots. A 

January 2007 inventory conducted for the Housing Plan identified 705 vacant residential lots, but noted 

that not all of these lots were available for sale and development. 

Residential development in Rock Springs continued during 2008 through early 2011, despite the 

economic slowdown. A total of 1,235 residential occupancy permits were issued by the city between 

January 2007 and April 15, 2011. Of the total occupancy permits issued, 40 percent were for singlefamily homes, 36 percent for apartments and 19 percent for duplexes. Rock Springs approved 14 

residential subdivisions with a combined capacity for 399 units between January 2007 and April 15, 2011 

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and the Planning Department estimates that that there were 134 vacant residential lots within city limits as 

of April 15, 2011 (McCarron 2011). 

The average price of an improved residential property (a lot with a house) in Rock Springs during 2006 

was $175,500, about 28 percent higher than the 2004 average of $137,500. The average price for 

unimproved residential property (a vacant building lot) increased from $48,958 in 2004 to $160,989 in 

2006, or 229 percent. According to the Housing Plan, these increases can largely be attributed to a 

shortage in available housing inventory and strong housing demand from an incoming workforce. In 

2010, the average sales price for residential properties was $174,257, virtually the same as 2006 (SWEDA 

2011). 

Although not establishing an affordable housing threshold, the Housing Plan suggested that given the 

relatively high per-capita personal incomes in Rock Springs ($38,039 in 2005), many local workers in 

Rock Springs could have afforded an average-priced home, if it were available.16 In addition, given the 

relatively large number of two-income households (43 percent in 2000), many households with members 

earning below-average incomes could have also afforded the average-priced home, if it were available. 

The Housing Plan forecasted future demand for housing units for purchase based on the plan’s population 

projections for the 2007–2017 period, the 2000 average household size of 2.48 persons per household, 

and various assumptions concerning housing preferences. The Housing Plan forecasted demand for 1,539 

new housing sales units and 1,100 new rental units by 2017. The Housing Plan also forecasted increased 

demand for senior housing, housing for persons with disabilities, and low-income households. This 

demand was based on a Rock Springs population forecast of 27,113 persons by 2017, contrasted with the 

WEAD forecast of 21,474 persons by 2017 (Rocks Springs’ 2010 population was 23,036 according to the 

2010 Census). 

Rock Springs has a total of 1,638 motel rooms (Sweetwater County Joint Travel and Tourism Board 

2009) 

Green River 

The U.S. Census Bureau counted 5,002 housing units in Green River in 2010, 13 percent more than the 

2000 census count of 4,426 units. A total of 159 of the total housing units were constructed between 2000 

and May of 2007. As of June 2011, there were only 39 available residential lots within Green River. 

However, two subdivisions with a total of 224 units were nearing final approval at that time (Brown 

2011). 

Green River has a total of 256 motel rooms (Sweetwater County Joint Travel and Tourism Board 2009). 

Wamsutter 

According to the 2010 census, the housing inventory in Wamsutter has nearly doubled over the past 

decade, growing from 148 units in 2000 to 286 units in 2010, an increase of 93 percent. Wamsutter had 

no available rental units during the summer of 2007 and very few vacancies during the summer of 2010. 

Temporary housing resources in Wamsutter include seven mobile home/RV parks with a total of 

160 spaces. Some drilling and gas-service contractors have put dormitory units in these mobile home 

parks. There are two motels in Wamsutter, one with 24 units, the other with 4 units, with a new 120-unit 

motel in the planning stages (Colson 2007 and 2010). 

3.15.4 Community Infrastructure and Services 

This section describes community infrastructure and services likely to be directly affected by the 

Proposed Action and alternatives. The following inventory identifies key public facilities and services 

16 Housing affordability and the ability to qualify for home mortgages are subject to other criteria in addition to earnings. 

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including law enforcement, emergency response (fire suppression and ambulance), hospitals, solid-waste 

disposal, and water and wastewater systems (schools are addressed in a following section). These are the 

services and facilities that have been and would be most immediately affected by energy development in 

the project area and elsewhere in the study area. However, all county and municipal services are affected 

by the demands associated with population growth. 

The experiences of the past decade illustrate both the benefits and the challenges that oil and gas 

development present for local government service delivery, particularly when that development is 

regional in nature. Although oil and gas development has been ongoing in southwestern Wyoming for 

decades, the advances in drilling in and producing from tight sands and other unconventional formations 

led to a surge in development throughout southwestern Wyoming as well as nearby regions of Wyoming, 

Colorado, and Utah during the early to middle years of the last decade. 

Because oil and gas development typically involves multiple companies operating in multiple fields 

across a region, growth in development activity, employment and, consequently, community population 

and service demand occurs in a decentralized manner. Communities are uncertain regarding the 

magnitude of growth and service demand that they may be facing, which hampers planning efforts. And 

although large-scale oil and gas development generates substantial increases in state and local 

government revenues, much of that revenue does not accrue until after the growth and increase in service 

demand has been ongoing for sometime, and in the case of Wyoming, key revenue sources such as ad 

valorem taxes on production are not available to municipalities, where much of the service demand 

occurs. These factors, coupled with the previously described housing shortages and competition for labor, 

contributed to challenging times for most of the local governments within the CD-C study area during the 

energy expansion period of the last decade. 

Then, when the sub-prime mortgage crisis, the ensuing global recession and other factors resulted in 

falling natural gas prices in the latter part of the decade, industry activity and employment experienced a 

corresponding decrease. Although a reduction in transient workers provided a respite from growth and 

service demand, the corresponding drop in natural gas-related revenues presented a fiscal hardship for 

communities that had added staff and begun infrastructure improvements to accommodate the growth. 

Once oil and gas development reaches an equilibrium of relatively constant drilling and field development 

activities and once development is completed and fields are producing, host counties and nearby 

communities typically can prosper and use the incremental revenues to improve infrastructure and 

services and accommodate the relatively stable population. However, the beginning and end of 

development cycles and the surges and declines resulting from decreases in commodity prices and 

demand are particularly challenging for affected local governments. 

3.15.4.1 Law Enforcement 

Law enforcement services are affected by natural gas development and production activities in the project 

area in terms of demand for law enforcement agency response to accidents and law enforcement incidents 

within and on highways providing access to the project area, as well as in terms of demand for services 

from the workforce and population generated by drilling, field-development, and production activities. 

Affected law enforcement agencies include the Carbon and Sweetwater County Sheriff’s Departments 

and the Rawlins, Baggs, Rock Springs, and Green River Police Departments.17 

During the boom years, energy development-related effects on law enforcement agencies included 

difficulty in recruiting and retaining officers, due in some cases to the higher wages paid by the energy 

industries and by larger law enforcement agencies, and due in part to the difficulty in finding affordable 

housing. The time and cost to train and equip an inexperienced officer affected law enforcement agency 

budgets, particularly when officer turnover was high. Most law enforcement agencies reported 

17 Law enforcement services in Wamsutter are currently provided by the Sweetwater County Sheriff’s Department. 

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substantially increased levels of certain types of offenses associated with the large, temporary, and 

transient component of the drilling and field-development workforce, which included a high percentage of 

single-status working-age males. Increases in traffic offenses, alcohol-related offenses and minor assaults 

were typical. All agencies report substantial increases in drug-related offenses, particularly 

methamphetamine (Carnes 2007, Claman 2007 and 2011, Colson 2009, Corners 2007, Jackson 2007, 

Lowell 2007, Morris 2007 and 2010, Reed 2007, Steffen 2007). 

The Carbon and Sweetwater County Sheriff’s Departments experienced increases in calls for service 

related to industrial accidents, vehicle accidents, crime, and traffic infractions in remote parts of their 

respective counties resulting from the intensification of drilling and field-development activities in 

previously isolated and seldom-visited areas (Claman 2007 and 2011, Colson 2007 and 2010). 

Criminal detention facilities in the two counties are operated by the respective Sheriff’s Departments. The 

Sweetwater County Detention Facility has a design capacity of 208 inmates and was designed to allow 

expansion on the same site while maximizing use of administrative facilities. In 2007, occupancy 

averaged about 110 inmates and recent (summer 2011) occupancy was slightly higher (110 to 120), in 

part because the detention facility has been housing inmates from other counties. The Carbon County 

Detention Facility, which opened in 2004, has a design capacity of 78 beds. During the summer of 2009 

the facility’s design capacity was exceeded a number of times. Consequently the detention facility 

appears to have reached its capacity sooner than the 10–15 years anticipated when it was constructed. 

Law enforcement and emergency-response dispatch services within the project area are provided by the 

Carbon and Sweetwater County Sheriff’s Departments. The Sweetwater County 911 service is 

administered by the Sweetwater County Emergency Management Agency, a division of the Sheriff’s 

Department. The Rawlins, Rock Springs, and Green River police departments also provide dispatch 

services (Carnes 2007, Claman 2007 and 2011, Colson 2009, Corners 2007, Jackson 2007, Lowell 2007, 

Morris 2007 and 2010, Reed 2007, Steffen 2007). 

3.15.4.2 Emergency Management and Response 

Emergency management and response is coordinated in Carbon County by the Carbon County 

Emergency Management Agency and in Sweetwater County by the Sweetwater County Emergency 

Management Agency. Both of these agencies coordinate emergency management and response in their 

respective portions of the project area and have recently established cooperative emergency-response 

staging locations within the project area, which allows employees working in remote areas to meet 

emergency responders at predetermined areas to guide them to remote accident locations. 

Fire-suppression and emergency-response services in the Carbon County part of the project area are 

provided by the Carbon County Fire Department (Rawlins and Baggs divisions) assisted as necessary by 

the Rawlins Fire Department. Fire suppression services in the Sweetwater County part of the project area 

are provided by the Sweetwater County Fire Department, aided by the Wamsutter Volunteer Fire 

Department. Rawlins, Rock Springs and Green River also operate fire departments for their communities 

and surrounding areas. 

Ambulance service in the northern and western part of Carbon County including a portion of the project 

area is provided by Memorial Hospital of Carbon County. In the southwestern part of the county, 

ambulance services are provided by the Noyes Medical Clinic & Ambulance Service, which is located in 

Baggs. The Wamsutter Volunteer Ambulance Service responds to calls along I-80 and to calls within 

much of the central portion of the project area. Vase Emergency Medical Services provides ambulance 

services in Rock Springs and along I-80. Castle Rock Ambulance Service provides ambulance services in 

Green River (Carnes 2007, Carter 2007, Hannum 2007, Jones 2007, Kennedy 2007, Valentine 2007, Sarff 

2007, Zabel 2007, Zeiger 2010). 

The Rawlins Interagency Dispatch Center provides a central location for reporting all wildland fires in 

southern Wyoming. Additionally, the BLM RFO and RSFO maintain trained and equipped fire crews that 

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respond to wildland fires on BLM surface and if needed will support other agencies on other federal, 

state, and private lands. 

3.15.4.3 Hospitals and Health Care 

Hospital and emergency-room services in the study area are provided by Memorial Hospital of Carbon 

County (MHCC) and Memorial Hospital of Sweetwater County (MHSC). MHCC is a 35-bed acute-care 

facility located in Rawlins and designated as a Community Trauma Hospital by the state of Wyoming. A 

Community Trauma Hospital must have a surgeon on staff. MHCC’s emergency room is staffed 24 hours 

per day, seven days per week with an emergency-care physician, a registered nurse and emergency 

medical technicians. Currently the hospital has staffing and facility capacity to serve substantially more 

patients than are currently treated. During the summer of 2010, MHCC had eight active medical staff 

physicians, over 35 courtesy (visiting) physicians and five locum tenens physicians who are hired on a 

temporary, short-term basis to fill in when active medical staff are on leave (Jessop 2010). 

MHSC is a non-profit, 99-bed, rural acute-care facility located in Rock Springs. As of 2010, MHSC had a 

total staff of 363 and 112 physicians, including locum tenens and consulting physicians (MHSC 2011). 

During the peak of the recent gas expansion in southwestern Wyoming, MHSC reported an average 20 

percent occupancy rate during 2008 (Wyoming Healthcare Commission 2008). During that period MHSC 

experienced an increased use of hospital emergency rooms for non-emergency care and increased 

uncollected debt attributed to the large number of workers who did not have health insurance and an 

increase in charity-care cases. The increase in emergency-room visits was largely attributed to non-local 

workers who did not have primary-care physicians in the area (Hawk 2007). 

There are medical clinics in Rawlins and Baggs and a number of clinics in the Rock Springs/Green River 

area. Carbon County had 13 licensed practicing physicians during 2007 (the most recent year for which 

physician data were published) or 0.85 physicians per thousand population, substantially below the 

Wyoming and national averages of 1.94 and 2.81 per thousand, respectively. Sweetwater County had 39 

physicians, or 1.01 per thousand, also below the Wyoming and national averages (Wyoming Healthcare 

Commission 2008). A lack of affordable housing in the community during the height of the natural gas 

boom added to the difficulty of recruiting physicians and staff. (Carter 2007, Hawk 2007, Jones 2007). 

3.15.4.4 Solid Waste Management 

In 2006 the Wyoming legislature passed a law requiring all operating landfills to prepare Integrated Solid 

Waste Management (ISWM) plans to be submitted to the WDEQ by July 1, 2009. All entities in 

communities affected by the Proposed Action and alternatives participated in the ISWM planning process. 

Three special districts—Baggs Solid Waste and Sweetwater County Solid Waste Disposal Districts 

(SCSWDD) # 1 and #2—are funded in part by mill levies on property within each district. 

Rawlins operates its own landfill, which has a remaining life of several years at the current fill rates. The 

City is currently seeking to obtain an additional section of land from the BLM to expand the landfill. 

Rawlins, along with Casper, Douglas, and other east-central Wyoming communities, is a member of the 

East Central Solid Waste Management Area As of February 2011, Rawlins ceased the disposal of 

municipal solid waste at the Rawlins landfill and began transporting its solid waste to the Casper 

Regional Landfill. Construction waste will continue to be accepted at the Rawlins Landfill through year 

2016 when a permit extension will be considered. The need for cover material to continue current landfill 

usage is an ongoing concern for the landfill operation. Disposal fees are designed to cover costs and some 

construction waste is recycled (City of Rawlins 2011, Stolns 2007 and 2009). 

The Baggs Solid Waste Disposal District operates the Baggs landfill, which has considerable capacity at 

its existing site, but has recently opted to transport baled municipal solid waste and recycled materials to 

the Casper Regional Landfill. Construction and demolition waste and animal carcasses will still be 

accepted at the Baggs landfill (Good 2011). 

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SCSWDD #1 oversees a landfill in Rock Springs, and monitors closed landfills in Reliance, Superior, and 

Point of Rocks (SCSWDD#1 2007). The district is completing a permit process that will provide the Rock 

Springs landfill with an estimated 30 years of remaining life at current fill rates and the district owns an 

adjacent 320 acres, which could provide additional capacity when permitted (Herman 2011, Sugano 

2007). SCSWDD #1 is part of the I-80 Solid Waste Management Planning Area along with SCSWDD #2 

(Wamsutter/Bairoil), Baggs, Farson, Eden and Green River. The Rock Springs landfill is in the process of 

becoming a regional landfill. The emerging plan will include the development and operation of transfer 

stations in some other municipalities and transportation of solid waste to the Rock Springs landfill. 

Currently the Sweetwater County communities of Farson and Eden transfer their waste to the Rock 

Springs landfill. 

Green River intends to close its currently operating landfill in approximately four or five years and begin 

transferring solid waste to the Rock Springs landfill (Herman 2010, Nelson 2007). 

SCSWDD #2 serves eastern Sweetwater County from the eastern border of the County to Point of Rocks, 

including the towns of Bairoil and Wamsutter. District #2’s landfill fill rates more than doubled during 

the boom years and the district’s landfill, located just south of Wamsutter, was within several months of 

its maximum capacity. The district received authorization from DEQ to expand the existing landfill 

vertically, which provided it five to eight additional years of use at current fill rates. The district has 

applied for permits to develop a new landfill adjacent to the existing landfill on the remaining 20 acres of 

the district’s 40-acre site, which will give the district an additional 25 years of capacity at current fill rates 

(Rigano 2007 and 2011, Pilch 2011). 

Disposal of solid waste from energy development has been of concern to community landfills and solid 

waste districts in the past. Currently, most solid waste from energy development and operations 

throughout the I-80 Solid Waste Management Planning Area is transferred to the Rock Springs landfill 

for disposal. Disposal of waste from drilling reserve pits is a concern for some solid waste districts 

(Herman 2011). 

3.15.4.5 Water Treatment, Storage, and Distribution 

Rawlins Water System 

The Rawlins water system, which also provides treated water for the town of Sinclair, was developed in 

the 1970s with a target capacity to serve about 17,000 residents. The system includes an 8-million-gallonper-day (MGD) treatment plant, which registered a 2006 peak daily usage of 4.45 MGD. Consequently, 

the water-treatment plant could serve nearly double the current population at current usage rates. The 

system includes four storage tanks, with a combined capacity of 6 million gallons for the city and a single 

0.8-million-gallon tank for Sinclair. There also is a raw-water storage reservoir that feeds the treatment 

plant. Rawlins has ample water rights in the North Platte River watershed and in springs and wells to 

serve both current and anticipated future water needs (Stolns 2008). 

Baggs Water System 

The Baggs wastewater treatment system is comprised of a four-cell aerated lagoon, which has been in use 

since 2006. The site includes a location for adding a fifth cell in the future. The system has capacity to 

treat about 100,000 gallons per day (Corners 2008, O’Neil 2007). Recent wastewater system 

improvements have included replacement of the pumps at the lagoon, nearly all of the vitrified clay pipes 

in the collection system, and some damaged PVC wastewater collection mains, as well as up-sizing all 

mains and installing two additional lift stations (Christopher 2011). 

Rock Springs Water System 

The Green River/Rock Springs/Sweetwater County Joint Powers Water Board supplies water to Rock 

Springs. The water storage and distribution system could serve a population of about 35,000. Each year 

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the Rock Springs Public Services Department replaces and improves a portion of the water distribution 

system in the older parts of the city. Water main extensions to neighborhoods on the perimeter of the city 

are sized to accommodate additional growth (Walker 2007 and 2011). 

Green River Water System 

Green River obtains treated water from the Green River/Rock Springs/Sweetwater County Joint Powers 

Water Board treatment plant, located in Green River. Although the system requires certain distribution 

and treatment improvements, there is capacity to accommodate additional users (Nelson 2007, Michael 

2011). 

Wamsutter Water System 

Wamsutter recently completed a series of improvements to the town’s water system; a 400,000-gallon 

water-storage tank north of town (funded in part by $1,213,000 from capital facilities sales tax revenues), 

construction of a water main connecting the industrial park to the town’s water system (funded by 

$954,716 from the capital facilities sales tax), and installation of water meters (funded by a $538,000 loan 

from the Wyoming State Revolving Loan Fund). A new well intended to be Wamsutter’s main water 

source came online in November of 2007; the Town is completing a water-treatment project and has 

received funding to study the siting of a new water source for the town. The town’s water system 

improvements are designed to accommodate a target population of 1,200 (Colson 2007 and 2010). 

3.15.4.6 Wastewater Collection and Treatment 

Rawlins Wastewater System 

The wastewater system for Rawlins was designed for a target population of 17,000; recent usage is about 

half of maximum capacity. The system has three aerated lagoons, two settling lagoons, and two storage 

lagoons. In order to achieve maximum capacity several lagoons would need to be cleaned and 

restructured. It is possible that the wastewater treatment system would need to be upgraded to tertiary 

treatment if substantial growth were to occur. There are currently over 65 miles of wastewater collection 

lines within the city and recent expansions have extended the collection system to serve additional land 

along I-80 (Stolns 2007, 2008 and 2010). 

Baggs Wastewater System 

The Baggs wastewater treatment system includes a four-cell aerated lagoon system and all cells have been 

in use since 2006. The site includes a location for a fifth cell, but it has not yet been constructed. The 

system has capacity to treat about 100,000 gallons per day (Corners 2008, O’Neil 2007). Recent 

wastewater system improvements have included replacement of the pumps at the lagoon, replacement of 

nearly all of the vitrified clay pipes in the collection system, replacing some damaged PVC wastewater 

collection mains and up-sizing all mains and installing two additional lift stations (Christopher 2011). 

Rock Springs Wastewater System 

The Rock Springs wastewater treatment plant capacity was expanded to 4.2 MGD in 2007. During 2010, 

the plant processed 2.3 to 2.45 MGD and served a population of about 25,000. The expanded plant has 

planned treatment capacity for a population of about 50,000 and was designed to accommodate a second 

plant on the same site, if required (Gaviotos 2007, Conner 2010). Work is currently underway to convert 

the treatment plant back to an anaerobic system. The Rock Springs Public Services Department replaces 

and upgrades portions of the wastewater collection system each year in older parts of the city and designs 

collection system extensions to growth areas of the city to accommodate future growth (Walker 2007 and 

2011). 

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Green River Wastewater System 

The Green River wastewater treatment plant has a 1.5-MGD treatment capacity and treated about 1.0 

MGD during 2007. Although the plan has capacity to accommodate additional growth, a recent 

wastewater master-plan study identified a number of areas in the wastewater-collection system requiring 

improvement to accommodate new growth and more effectively move wastewater to the treatment plant 

Michael 2011, Nelson 2007). 

Wamsutter Wastewater System 

Wamsutter recently completed construction of a wastewater-collection main to connect the industrial park 

and other system improvements to the wastewater system, and conducted a capacity analysis of its 

wastewater lagoon system to determine short- and long-term needs. The analysis was funded by a 

$16,500 grant from BP America. The current system is designed to serve a population of about 1,200 and 

Town staff believes that at peak, the system served about 850. The Town intends to expand and improve 

the wastewater system to accommodate a population of 2,500. (Carnes 2007, Colson 2007 and 2010). 

3.15.5 Local Government Fiscal Conditions 

Natural gas development in the project area would affect certain local, state, and federal government 

revenues and expenditures. Affected revenues would include ad valorem property tax revenues of Carbon 

and Sweetwater counties; Carbon County School District #1, Sweetwater County School District #1 and 

certain special districts; sales and use tax revenues of the State of Wyoming, the two counties, and their 

municipalities; state severance taxes; and federal mineral royalties. The two counties and the affected 

school districts, special districts, and municipalities would also see increases in expenditures to serve 

development and associated population growth. This section describes existing conditions and trends in 

the local government jurisdictions that are likely to be affected by the proposed CD-C project. 

3.15.5.1 County Fiscal Conditions and Trends 

Ad Valorem/Property Tax Trends 

Ad valorem taxes, commonly known as property taxes, constitute an important share of the revenue base 

of Carbon and Sweetwater Counties, and for local school districts. The basis for local property taxes in 

Wyoming is the assessed valuation of real and personal property, utilities, and mineral production. Driven 

largely by increases in mineral valuation, the ad valorem tax base has grown substantially over the past 

decade, despite a sharp drop from 2009 to 2010 (see Figure 3.15-6). Sweetwater County total assessed 

valuation exceeded $2.1 billion in 2010; nearly $900 million lower than in 2009 but still nearly double the 

$1.1 billion recorded in 2000. Assessed valuation also climbed dramatically in Carbon County over the 

past decade, from $337 million in 2000 to nearly $800 million in 2010. The net change in Carbon County 

included jumps of more than $200 million from 2005 to 2006 and from 2008 to 2009, but a sharp decline 

of more than $450 million from 2009 to 2010. 

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$0 

$500 

$1,000 

$1,500 

$2,000 

$2,500 

$3,000 

$3,500 

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 

Millions 

Carbon Sweetwater 

Figure 3.15-6. Total assessed value, Carbon and Sweetwater Counties, 2000–2010 

Source: Wyoming Department of Revenue, 2003–2010. 

Valuation on oil and gas production has accounted for most of the changes in assessed value, more than 

quadrupling between 2000 and 2009 in Carbon County and tripling in Sweetwater County. That growth 

reflected both rising energy prices and increased production. As a result of that growth, the assessed value 

on minerals currently accounts for approximately 80 percent of the total valuation in both counties. 

However, as is readily apparent locally, these valuations are subject to substantial year-to-year volatility 

due to the volatility in global energy prices. Between 2009 and 2010, the assessed value of mineral 

production in these counties declined by nearly 50 percent in Carbon County and over 40 percent in 

Sweetwater County. 

Sales and Use Tax Conditions and Trends 

Another key source of revenue for counties and incorporated communities are sales and use taxes 

imposed by the state and, when approved by the local electorate, the counties themselves. The state sales 

and use tax of 4 percent is collected based on the point of sale, a share of which is redistributed back to 

local governments. The share returned to counties and incorporated municipalities (a statutorily 

prescribed amount, currently 31 percent of statewide total receipts) is on a population-based formula, 

irrespective of where the sales were generated. Counties can elect to impose a 1-percent general-purpose 

local tax and a 1-percent specific-purpose tax for capital improvements. Carbon and Sweetwater Counties 

currently each impose the general-purpose 1-percent levy and Carbon County imposes the 1-percent 

special-purpose option tax. The state collects these taxes and distributes the local share based on the 

above-referenced formula. 

Figure 3.15-7 and Tables 3.15-5 and 3.15-6 summarize the sales, use, and lodging tax distributions by 

the state to the two counties in recent years. The reported distributions include both the full distribution of 

local-option taxes and the respective county’s proportional share of the state taxes. The tables also show 

the total amount of sales and use tax receipts collected from each of the counties for activities occurring 

within their respective boundaries, providing a comprehensive measure of the changes in taxable sales 

activity over the period. 

Figure 3.15-7 displays the general pattern of growth and then decline in recent years in response to the 

level of natural gas development and related capital investment, for example, in compression and pipeline 

transmission capacity. Declines of approximately 30 percent occurred in each county between 2009 and 

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2010; the absolute declines amounting to more than $39 million in Sweetwater County and more than $8 

million in Carbon County. 

$0 

$20 

$40 

$60 

$80 

$100 

$120 

$140 

$160 

2004 2005 2006 2007 2008 2009 2010 

Millions 

Carbon Sweetwater 

Figure 3.15-7. Annual sales and use tax distributions to Carbon and Sweetwater Counties, fiscal years 

2004–2010 

Source: Wyoming Department of Revenue, Annual Reports. 

As shown above and in Table 3.15-5, total sales and use tax revenues distributed to Carbon County, 

largely reflecting the increase in natural gas development activity, more than doubled from 2004 to 2007, 

then declined to just over $34 million in 2008 as a 1-percent specific-purpose local-option tax expired. 

Continuing natural gas development activity, along with construction activities at the Sinclair refinery 

supported a modest increase in receipts to $36 million in 2009. Completion of the major construction 

activities at the refinery and the effects of the recession on the statewide and local economies took hold in 

2010, resulting in a decline of more than $8 million. The significance of the local-option taxes is readily 

apparent, generating more than $13.0 million in sales and use tax revenues for Carbon County in 2007. 

The total local-option tax receipts declined to $9.0 million in 2010. 

Table 3.15-5. Annual sales, use, and lodging taxes generated by sales in Carbon County, by levy 

Tax Levy 

Fiscal Year 

2006 2007 2008 2009 2010 

General-purpose local sales $4,481,031 $5,466,724 $ 5,625,450 $6,293,772 $3,955,550 

General-purpose local use 409,374 1,368,627 1,077,816 717,474 596,977 

Specific-purpose local sales 4,450,047 4,879,915 50,200 454,429 3,924,130 

Specific-purpose local use 407,808 1,306,446 - 21,491 87,900 598,009 

State sales 17,924,890 21,867,275 22,502,258 25,175,135 15,822,251 

State use 1,637,544 5,475,415 4,311,431 2,871,311 2,387,907 

Lodging 307,846 405,083 472,174 432,060 377,233 

Total revenue generated $29,618,540 $40,769,485 $34,017,838 $36,032,081 $27,662,057 

Sources: Wyoming Department of Revenue, Annual Reports, and Wyoming Department of Administration and Information, 

Wyoming Sales, Use, and Lodging Tax Report, Annual Series 2002–2010. 

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Sweetwater County sales and use taxes generated by local activity have increased sharply over time. 

Much of the growth reflects the effects of economic expansion through 2009, although locally levied 

specific-purpose local-option taxes have generated more than $20 million annually from 2007 to 2009. 

Sales and use tax revenues declined by $39 million between 2009 and 2010, a 29 percent decline. The 

high level of sales and use tax attributable to the mining sector in Sweetwater County reflects the trona 

and coal-mining base within the county as well as oil and gas development (Table 3.15-6). 

Table 3.15-6.	 Annual sales, use and lodging tax generated by sales in Sweetwater County, by levy 

TAX LEVY 

Fiscal Year 

2006 2007 2008 2009 2010 

General-purpose local sales $15,520,807 $ 18,621,968 $ 17,756,577 $ 18,886,147 $14,120,339 

General-purpose local use 2,813,858 3,571,329 4,385,679 3,561,457 2,915,227 

Specific-purpose local sales 1,789,959 18,217,172 17,688,132 18,781,477 8,969,716 

Specific-purpose local use 310,554 3,551,219 4,431,882 3,604,861 1,579,204 

State sales 62,122,000 74,528,846 71,058,754 75,549,214 56,495,696 

State use 11,255,462 14,285,373 17,543,373 14,247,199 11,661,191 

Lodging 551,209 691,139 742,203 704,232 516,051

 Total revenue generated $94,363,849 $133,467,046 $133,606,600 $135,334,587 $96,257,424 

Source: Wyoming Department of Revenue, Annual Reports; and Department of Administration and Information, Wyoming Sales, 

Use, and Lodging Tax Report, Annual Series, 2002–2010. 

The mining industry is a major generator of state and local sales and use tax revenues in Carbon County 

and changes in mining activity, including new oil and gas development, translate into differences in tax 

receipts. The receipts yield fiscal benefits statewide through various redistribution formulas. 

Sales and use tax collections reported by the mining industry for the five years immediately preceding the 

recent economic recession exceeded $145 million, representing approximately 25 to 30 percent of the 

total annual revenues generated by the state sales and use tax levies in the two counties during that period 

(Table 3.15-7). These revenues are derived largely from oil and gas development, and of that total, 

approximately 51 percent accrued to the state coffers or was distributed to other communities. 

Table 3.15-7.	 Annual sales and use tax collections by the mining industry in Carbon and Sweetwater 

Counties, 2006–2010 

 Fiscal Year 

2006 2007 2008 2009 2010 

Sales and Use Taxes Collected by the Mining Industry in Carbon County 

Total state sales and use 

(from Table 3.15-5 above) $19,562,434 $27,342,690 $26,813,689 $28,046,446 $18,210,158 

State sales and use tax 

reported by mining 5,006,293 8,172,047 7,570,549 8,017,405 3,540,632

 Percent by mining 25.6% 29.9% 28.2% 28.6% 19.4% 

Sales and Use Taxes Collected by the Mining Industry in Sweetwater County 

Total state sales and use 

(from Table 3.15-6 above) $73,377,462 $88,814,219 $88,602,127 $89,796,413 $68,156,887 

State sales and use tax 

reported by mining 19,534,344 26,514,528 25,192,508 25,948,033 15,644,884 

 Percent by mining 26.6% 29.9% 28.4% 28.9% 23.0% 

Sources: Wyoming Department of Revenue, Annual Reports, and Wyoming Department of Administration and Information, Sales 

and Use Tax Distribution Reports, Annual Series 2002–2010. 

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CHAPTER 3—AFFECTED ENVIRONMENT—SOCIOECONOMICS
 

3.15.5.2 County Revenues and Expenditures 

Property, sales, and use taxes combine to account for the major share of county revenues. However, 

counties have many other revenue sources, ranging from fees for services to federal payment-in-lieu-oftaxes, and distributions of severance tax and mineral royalties from the state. Historically, Carbon County 

also has received various grants to address capital needs, but the amount and timing of such grants is 

highly variable. 

Table 3.15-8 shows total fund revenues and expenditures in several broad categories for Carbon County’s 

general fund over the past three fiscal years. As shown, property tax receipts increased by $2.7 million 

from 2009 to 2010 in response to increases in assessed valuation, driven primarily by mineral valuation. 

Budgeted expenditures for selected departments that tend to be sensitive to growth increased from 2008 to 

2009 and were budgeted to increase again in 2010. However, as described elsewhere, the economic 

downturn and reduction in the pace of development had noticeable adverse effects on revenues; actual 

revenues from sources other than property taxes were 40 percent below the budgeted sums. Consequently, 

the County’s total general fund revenue was 22 percent below budget, requiring substantial reductions in 

operating outlays, deferral of planned capital outlays, and use of reserve funds. While the recession may 

have resulted in some reductions in service demand, the severity of the cutbacks resulted in diminished 

levels of service for county residents. 

Table 3.15-8. General fund revenues and expenditures, Carbon County 

FY2008 

Actual 2009 2010 Original 

2010 Adjusted 

Actual 

Change 2010 

Original vs. 

Adjusted 

General Fund Revenue 

Property tax revenue $ 9,603,868 $ 9,700,506 $12,472,882 $12,472,882 0% 

Other revenue 11,999,836 12,156,935 15,976,118 9,593,391 -40% 

Total revenue $21,603,704 $21,857,441 $28,449,000 $22,066,273 -22% 

General Fund Expenditures 

Select departments 

 Criminal justice $ 1,507,178 $ 1,674,792 $ 1,743,346 $ 1,691,878 -3% 

 Sheriff 1,467,007 1,704,024 2,139,065 1,654,892 -23% 

 Jail 1,749,921 1,913,701 3,032,959 2,583,053 -15% 

 Road and bridge 2,310,140 3,393,772 3,253,057 2,015,528 -38% 

Select departments 

subtotal $ 7,034,246 $ 8,686,289 $10,168,427 $ 7,945,351 -22% 

All other departments 13,414,088 13,277,770 31,176,149 12,826,271 -59% 

Total General Fund 

Expenditures $20,448,334 $21,964,059 $41,344,576 $20,771,622 -50% 

1

 Other includes all other departments, budgeted capital outlays and closing balances/reserves. The 2010 original budgeted 

expenditures included anticipated receipts of a $10 million grant.
 

Source: Carbon County, County Budget, FY 2008-10. 

Table 3.15-9 shows similar general-fund budget data for Sweetwater County. There too, the effects of the 

recession are apparent in declines in revenues and general fund expenditures from fiscal year 2008 to 

2009. Sweetwater County realized a net increase in tax revenues between 2009 and 2010, primarily 

derived from property taxes on mineral production which more than offset declines in sales and use tax 

receipts. Due to the lags between production and taxation on mineral valuation, a substantial reduction in 

property tax revenues and further reductions in sales and use taxes are anticipated for the 2011 budget 

year. 

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CHAPTER 3—AFFECTED ENVIRONMENT—SOCIOECONOMICS 

Table 3.15-9. General fund revenues and expenditures, Sweetwater County (in millions) 

FY2008 FY2009 FY2010 

General fund revenue 

Property tax revenue $18.54 $19.25 $28.51 

Other revenue, excluding transfers 24.73 20.94 18.97 

Total revenue $43.27 $40.19 $47.48 

General Fund Expenditures 

 General government $27.79 $17.25 $18.52 

 Public safety 11.16 10.21 14.38 

 Road and bridge 5.50 4.43 4.41 

 Other miscellaneous 0.21 0.22 1.30 

 Capital outlay 0.00 7.32 5.57 

Total expenditures $44.66 $39.43 $44.18 

 Changes in reserves ($1.39) $0.76 $3.17 

Source: Sweetwater County, Sweetwater County Budget Audit Reports, FY 2009 and 2010. 

Figure 3.15-8 summarizes the total annual general fund revenues for Carbon and Sweetwater Counties 

for fiscal years 2004 through 2010, illustrating the volatility in tax revenues associated with naturalresource development. Because the timing and magnitude of the changes are often not foreseeable and 

can come about relatively quickly, the year-to-year changes in revenues, coupled with the subsequent 

implications for budgeted expenditures, pose important challenges for local government The challenges 

can be particularly acute with respect to planning and funding large-scale capital improvement projects 

and to expanding current services during periods of rapid growth. 

$0.0 

$5.0 

$10.0 

$15.0 

$20.0 

$25.0 

$30.0 

$35.0 

$40.0 

$45.0 

$50.0 

2004 2005 2006 2007 2008 2009 2010 

General Fund Revenue (Millions) 

Carbon County 

Sweetwater County 

** The 2007 revenue shown for Carbon County excludes a one-time $10 million grant. 

Figure 3.15-8. General fund revenues for Carbon and Sweetwater Counties, 2004–2010 

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CHAPTER 3—AFFECTED ENVIRONMENT—SOCIOECONOMICS 

3.15.5.3 Municipal Fiscal Conditions and Trends 

Property Taxes 

Property taxes are a less significant, but still important revenue source, for municipalities than for 

counties. Unlike county-wide valuations that rely heavily on mineral valuation, municipal valuations are 

more heavily based on the real estate. The dependency on real estate reduces the volatility in year-to-year 

valuations for municipalities, as compared to that for counties. Because of the latter factor, trends in 

assessed valuation are important indicators of local economic growth. 

As shown in Table 3.15-10, Green River, Rawlins, and Rock Springs have relatively large ad valorem tax 

bases, while the three smaller communities have much smaller property tax bases. The most significant 

trends disclosed by these data include the strong growth in valuations among the three large communities, 

and the recent declines in Wamsutter’s property tax base following its peak of $5.4 million in 2006. Rock 

Springs saw a 136-percent increase in assessed value between 2003 and 2010 due to its emergence as a 

regional service center for natural gas development, resulting in an assessed value nearly four times that 

of Rawlins and over twice that of Green River. 

Table 3.15-10. Total assessed value, affected cities and towns

 Fiscal Years Change 

2006-10 2006 2007 2008 2009 2010 

Green River $ 55,080,205 $64,197,337 $75,527,179 $76,962,206 $76,067,639 38.1% 

Rawlins 31,466,624 40,026,026 46,593,587 51,449,273 50,599,959 60.8% 

Rock Springs 119,965,719 146,505,485 179,056,974 194,302,844 191,988,774 60.0% 

Baggs 1,253,046 1,740,673 2,061,521 3,363,378 2,733,582 118.2% 

Wamsutter 5,438,372 1,804,230 2,791,829 3,988,816 3,942,481 -27.5% 

Source: Wyoming State Board of Equalization, 2009 and 2010, and Wyoming Taxpayers Association, 2007 to 2008. 

Sales and Use Tax Distributions 

Sales and use taxes are typically the single largest source of general-fund revenue for municipalities. That 

pattern applies to the affected municipalities in the project area. Table 3.15-11 shows the annual sales and 

use tax distributions reported by the state to each of the six potentially affected communities from 2005 

through 2010. The comparative distributions among the communities generally reflect their relative sizes, 

as well as differences in the level of economic activity and growth associated with the natural gas 

industry. 

Table 3.15-11. Total annual sales and use tax distributions, cities and towns 

City/Town 

Fiscal Year Change 

2005 2006 2007 2008 2009 2010 2009-10 

Green River $10,177,818 $12,668,279 $15,299,399 $15,252,520 $15,458,494 $11,728,814 -24% 

Rawlins 5,252,016 6,336,901 8,594,271 8,417,212 8,808,209 5,695,922 -35% 

Rock Springs 16,429,886 20,471,622 24,239,596 24,165,324 24,491,659 18,582,542 -24% 

Baggs 205,710 245,475 332,090 325,249 340,357 220,096 -35% 

Wamsutter 228,118 282,659 338,173 337,136 126,988 259,250 104% 

Source: Wyoming Department of Revenue, Sales and Use Tax Distribution Reports. 

As shown above, the local municipalities experienced substantial declines in sales and use tax 

distributions as the economic recession continued. In Rock Springs the total distribution dropped by $5.9 

million, or 24 percent. Rawlins experienced a larger decline, in relative terms, of 35 percent. The 

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unforeseen magnitude of these declines necessitated mid-year revisions in budgets, which translated to 

responses such as staff layoffs, deferral of planned hiring, cutbacks in services and programs, and 

cancellation or deferral of capital-improvement spending. 

Municipal Revenue and Expenditures 

Summaries of municipal general-fund revenues and expenditures were developed from budget documents 

of the selected cities and towns. These summary budgets are presented in Tables 3.15-12 through 3.15-

15. Although the organization of funds and level of detail provided in the municipal budgets varies among 

the communities, the summary budgets attempt to present comparable information for each municipality 

by assigning all revenues and expenditures to one of a broadly defined set of categories. Two conventions 

should be noted. First, the income category of “taxes” includes sales and use taxes returned to the 

municipalities by the state. Several of the source-document budgets listed such payments as 

“intergovernmental revenue.” Conversely, some “taxes” such as severance tax and mineral royalties are 

included in the summaries as “intergovernmental” even though some local budgets classified them under 

the “tax” heading. Second, in preparing the expenditure summaries, multiple departments are grouped 

into six categories with descriptive titles that do not necessarily mean only the department with a similar 

name. For example “public works” in the table could include the Public Works department, but also 

Streets, Engineering, Shops, Building Maintenance, and other physical facility and plant construction and 

maintenance activities. 

City of Rawlins 

Table 3.15-12 summarizes general-fund budget data for three years of recent budgets for the City of 

Rawlins. General fund revenues and expenses will effectively equalize over the long term, but there may 

be variances in any one year due to inter-fund transfers, contributions to or from reserves, and varying 

year-end cash balances. In Rawlins, budgeted revenue was anticipated to increase modestly over the 

three-year period, with approximately half of the total revenue from taxes. On the expenditure side, public 

safety accounts for the largest share of outlays. 

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Table 3.15-12. General fund revenue and expenditures, City of Rawlins 

2007-08 Actual 2008-09 Budget 2009-10 

Preliminary Budget 

Change 

2007-08 to 2009-10 

General Fund Revenue 

Taxes $ 7,454,450 $ 7,468,667 $ 8,348,500 12.0% 

Franchises 359,000 394,000 430,000 19.8% 

Intergovernmental 2,969,635 2,547,347 2,380,139 -19.9% 

Charges for services 1,053,513 1,077,050 1,030,200 -2.2% 

Police and court 354,700 387,400 390,900 10.2% 

Other revenue 119,500 82,900 71,140 -40.5% 

Transfers in 425,850 483,610 687,497 61.4% 

Beginning balance 2,638,736 3,820,237 3,593,656 36.2%

 Total Revenue $15,375,384 $16,261,211 $16,932,032 10.1% 

General Fund Expenditures 

Administration $ 2,511,368 $ 2,652,215 $ 3,097,286 23.3% 

Courts 287,597 289,915 284,631 -1.0% 

Public safety 4,666,059 5,059,741 5,234,031 12.2% 

Public works 2,482,836 2,426,548 2,937,439 18.3% 

Parks & recreation 1,623,278 1,291,187 1,314,228 -19.0% 

Miscellaneous 617,235 842,476 1,037,273 68.1% 

Capital improvements 1,060,242 1,473,192 274,349 -74.1% 

Ending balance 2,026,769 2,225,937 2,752,795 35.8% 

Total Expenditures $15,275,384 $16,261,211 $16,932,032 10.8% 

Source: City of Rawlins, Budget Worksheet, FY2009-10.
 

Note: Taxes include state-rebated sales and use tax.
 

Revenue shortfalls beginning in 2009 and continuing through 2010 necessitated amending the use of 

reserves, and cutbacks of more than $1.1 million in city spending to address the resulting deficit. The 

cutbacks included a reduction of 16 positions through attrition or layoffs. 

The proposed budget for 2010-2011 calls for another $1.1 million reduction in expenditures, with periodic 

reviews to monitor revenues, particularly sales and use tax proceeds. If necessary, the city may draw on 

its reserve account to preserve essential services. 

City of Rock Springs 

The City of Rock Springs has an annual general-fund budget more than twice that of Rawlins, with taxes 

again the largest single contributor to revenue (see Table 3.15-13). The City’s anticipated general 

revenues exhibit substantial year-to-year revenue variability due to transfers and unexpected changes in 

local economic activity. 

The City’s total budgeted general-fund expenditures decreased by 28 percent over the past 3 years. Sharp 

cutbacks in the budgets for public works and parks and recreation accounted for most of the reduction, 

while the budget for administration increased by about $2.1 million. 

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Table 3.15-13. General fund revenue and expenditures, City of Rock Springs 

2008-2009 Actual 2009-2010 Actual 2010-2011 Budget 

Change 

2010-2011 

General Fund Revenue 

Taxes $ 3,647,055 $ 3,762,761 $ 2,932,782 -22% 

Intergovernmental 34,175,579 35,645,049 31,573,137 -11% 

Charges for services 1,388,822 1,350,393 1,377,425 2% 

Fines and forfeitures 518,009 572,146 518,250 -9% 

All other, including transfers 3,234,759 5,638,559 1,833,039 -67%

 Total revenue $42,964,224 $46,968,908 $38,234,633 -19% 

General Fund Expenditures 

Administration $ 8,163,156 $ 8,571,182 $10,309,818 26% 

Municipal Court 398,800 430,351 439,101 10% 

Parks & Recreation 20,605,894 10,613,992 8,578,928 -58% 

Public Safety 13,297,227 12,802,508 12,376,084 -7% 

Public Works 11,484,602 11,956,730 7,343,680 -36%

 Total expenditures $53,949,679 $44,374,763 $39,047,611 -28% 

Note: Taxes include state-rebated sales and use tax. 

Sources: City of Rock Springs, Final Budget 2008–2009, 2009-2010, and 2010-2011.
 

City of Green River 

As indicated in Table 3.15-14, Green River’s general-fund revenues have declined by 27 percent over the 

last three years, with reductions in taxes comprising the majority of the decline. During the same period, 

total general fund expenditures increased by about 9 percent; the increase funded through the use of 

reserves. 

Table 3.15-14. Revenue and expenditures, City of Green River 

 2008–2009 Actual 2009–2010 Budget 2010–2011 Budget Growth 2008-10 

General Fund Revenue 

Taxes $ 17,290,036 $ 12,612,606 $ 11,858,377 -31% 

Intergovernmental 2,788,802 3,325,009 2,927,386 5% 

Charges for services 492,437 426,700 449,150 -9% 

Other & Miscellaneous 1,387,866 829,200 711,200 -49%

 Total revenue $ 21,959,141 $ 17,193,515 $ 15,946,113 -27% 

General Fund Expenditures 

Administration $ 3,010,274 $ 3,464,791 $ 3,284,419 9% 

Courts 5,119,193 5,555,267 5,526,219 8% 

Public safety 2,450,853 2,746,938 2,830,292 15% 

Public works 727,121 844,111 974,537 34% 

Parks & recreation 4,364,043 4,878,946 4,918,062 13% 

Total expenditures $ 15,671,484 $ 17,490,053 $ 17,533,529 9% 

Notes: Taxes include state-rebated sales and use tax. 

Source: City of Green River, Annual Budgets Fiscal Year 2008, 2009 and 2010. 

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3.15.6 Schools 

Three school districts could be affected by the CD-C project: 

 Carbon County School District #1 (CCSD #1) 

 Sweetwater County School District #1 (SCSD #1) 

 Sweetwater County School District #2 (SCSD #2) 

Figure 3.15-9 displays 1991–2010 fall enrollment statistics for the three affected school districts. All 

three districts had substantial enrollment declines through the 1990s and the first several years of the 

following decade. Thereafter all three districts experienced enrollment gains in concert with population 

growth associated with the increased pace of natural resource development. Enrollment gains continued in 

CCSD #1 and SCSD #2 through 2007 and 2008, respectively, but stabilized somewhat in subsequent 

years. Enrollment in SCSD #1 has grown steadily over the past seven years, gaining more than 960 

students since 2003. Fall 2010 enrollment counts, covering kindergarten through grade 12, were 1,810 for 

CCSD #1, 2,635 for SCSD #2, and 5,159 for SCSD #1. 

0 

1,000 

2,000 

3,000 

4,000 

5,000 

6,000 

7,000 

1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 

CCSD #1 SCSD #1 SCSD #2 

Figure 3.15-9. Fall enrollment, Carbon County School District #1 and Sweetwater County 

School Districts #1 and #2, 1991–2010 

Source: Wyoming Department of Education 2010, 2011. 

The differences in enrollment levels are reflected in their respective annual operating budgets and level of 

staffing (see Table 3.15-15). The pupil/teacher ratios for all three districts are slightly above the statewide 

median. 

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Table 3.15-15. School district revenue, staffing, and enrollment, 2009 

Fiscal Year 2009 

CCSD #1 SCSD #1 SCSD #2 

Total Revenue $19,717,769 $84,586,170 $52,736,915 

Staff (FTE) 

 Teachers 137.9 356.5 200.4 

 Others 139.6 483 264.9 

Total 277.5 839.5 465.3 

Enrollment 1,727 4,955 2,669 

Pupil/Teacher Ratio 12.5 13.9 13.3 

Source: Wyoming Department of Education 2009. 

All districts have historically had difficulty finding affordable housing for teachers. The districts have 

also occasionally had difficulty in recruiting and retaining maintenance and custodial staff and bus drivers 

during periods of economic expansion when labor shortage and the high wages paid in the energy 

industry put the districts at a competitive disadvantage for labor (Grube 2007, Sanders 2007, Sorenson 

2007). 

3.15.6.1 Carbon County School District #1 

CCSD #1 serves Rawlins, Sinclair, and the Little Snake River Valley (LSRV), including the communities 

of Baggs and Dixon and the Sweetwater County community of Bairoil. Currently CCSD #1 operates two 

elementary schools, a middle school, a high school, and a cooperative high school in Rawlins; elementary 

schools in Sinclair and Bairoil; and a K–12 comprehensive school in Baggs that serves the entire LSRV. 

Additionally the district operates a fine-arts center, a swimming pool, and a sports complex in Rawlins. 

The Rawlins Elementary School opened in early 2011. It currently has two learning communities, (grades 

2–3 and grades 4–5). The school is designed to allow the addition of a K–1 community. Currently, 

kindergarten and first-grade students are housed in the adjacent Highland Hills Elementary School, which 

is at capacity. Rawlins Elementary could accommodate an additional 100 students over the 2010–2011 

school year enrollment. The Rawlins Middle School can accommodate an additional 50 to 75 students. 

The Rawlins High School was designed to accommodate 1,100 to 1,200 students and fall enrollment was 

455 students. The high school is an aging and outsized facility that is inefficient to operate. The Wyoming 

School Facilities Commission has authorized construction of a new 500-student high school, but the 

district believes it will need capacity for 600 students given pending energy projects in the area. Sinclair 

elementary is approaching capacity and the Little Snake River K–12 school could accommodate an 

additional 40 or more students (Terhune 2011). 

3.15.6.2 Sweetwater County School District #1 

SCSD #1 serves eastern and central Sweetwater County, including the communities of Rock Springs, 

Farson, Eden, Superior, and Wamsutter. SCSD #1 has seven elementary schools, one junior high school, 

and two high schools (one traditional and one alternative) in Rock Springs. The district opened the new 

Pilot Butte Elementary, a 5–6 grade school, in the fall of 2011. SCSD #1 also operates a K–12 school in 

Farson; and a K–8 school in Wamsutter. The district closed eight schools between 1991 and 2003 due to 

declining enrollments. 

SCSD #1 has proposed to build an additional 5–6 grade school and a new junior high school. Longer-term 

plans include replacing the high school. School construction plans are subject to approval by the 

Wyoming School Facilities Department. 

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With new and planned facilities, SCSD #1 should be able to accommodate an additional 60 students per 

grade in the elementary schools. The new junior high school will have additional capacity, but the high 

school is currently near capacity with anticipated increases in enrollment in the coming years. The district 

has a plan to relocate a portion of the school to a satellite facility. The Wamsutter K–8 school currently 

has enrollment of about 8 to 12 students per classroom and could accommodate up to 23 students per 

classroom (Lopiccolo 2011). 

3.15.6.3 Sweetwater County School District #2 

SCSD #2 serves the western half of Sweetwater County including the communities of Green River, 

Granger, and McKinnon. SCSD #2 operates a high school (grades 9–12), an alternative high school 

(grades 10–12), a middle school (grades 7–8), and an intermediate school (grades 5–6). The District also 

maintains four K–4 elementary schools within the city limits and three rural elementary schools. The 

district has closed two elementary schools since 1990 due to declining enrollment. 

It is estimated that the four Green River K–4 elementary schools could accommodate a combined total of 

an additional 110 students and the 5–6 elementary school could accommodate an additional 20 students. 

There is some capacity to absorb new students in the middle school. The high school has a design 

capacity of 1,200 to 1,500 students and currently serves about 700 students (Little-Kaumo 2011). 

3.15.7 Social Conditions and Trends 

This section describes relevant social conditions and trends within in and near the CD-C project area. 

Specific social conditions associated with other users of the project area (grazing operators and 

recreationists) are also examined. Information for this section was obtained from over 60 interviews with 

community officials, local government staff, business persons, and ranchers; from review of scoping 

comments and newspaper articles; and from other secondary sources as cited. 

Section 2 of the Baseline STR describes the human geography of the study area, discusses human 

settlement of the area, characterizes the communities, and describes the economic influences that have 

helped shaped the region and the individual communities. Although these communities share elements of 

a common heritage and regional geography, each has its own distinct economic, demographic and social 

setting. 

3.15.7.1 Common Social Elements and Trends 

Over the past decade, the communities in the study area experienced an economic expansion fueled by 

energy development in the project area and elsewhere in the bi-county region and in much of southwest 

Wyoming, and then a rapid contraction resulting from the sub-prime mortgage crisis, the ensuing global 

recession, and falling energy prices. The social effects of the recent expansion and contraction provide 

valuable insights into potential effects of the Proposed Action and alternatives on social conditions in the 

area. 

The recent expansion was the latest in a series of regional economic expansion and contraction cycles 

dating back to the construction of the transcontinental railroad but more recently associated with mineral 

and energy development. The larger communities in the study area have a somewhat economically 

diverse population resulting from the influences of the ranching, energy, mining, and transportation 

industries and federal and state government offices and facilities. Wamsutter, Baggs and the other smaller 

communities are much less diverse economically. Wamsutter, although formerly a railroad and woolshipping center, has recently become dependent on the energy industry and I-80 commerce. Of the 

communities in the study area, Baggs and the LSRV remain most closely tied to the ranching and outdoor 

recreation (principally hunting) industries, although a number of residents of Baggs and the LSRV are 

employed by or provide services to the energy industry and Devon Energy operates a field office in 

Baggs. 

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Even during the current (mid-2011) economic contraction there are reduced levels of energy development 

activity and in- and out-migration associated with the energy and mining sectors. Communities in the 

study area are familiar with energy industries and with the relatively constant stream of newcomers to 

these communities. However, during the recent expansion, which began in 2002/2003 in Sweetwater 

County and 2004/2005 in Carbon County, economic and population growth occurred at levels not seen 

for more than two decades in these two counties. Local communities are in agreement that federal and 

state population statistics did not reflect the magnitude of growth and there were no reliable estimates of 

the number of energy workers who stayed in communities on a temporary basis. 

As a result of the economic and population growth and the presence of relatively large numbers of 

temporary and transient, predominantly male workers in these communities, social conditions in affected 

communities were changing at a relatively rapid pace. Many of the “boom-town” phenomena (e.g. 

housing shortages and escalating housing costs, workforce shortages, elevated rates of certain types of 

crime) reported by researchers in the late 1970s and early 1980s once again emerged. Social settings 

within the study area such as stores, restaurants, bars, and post offices were increasingly crowded and 

from a local resident’s perspective, filled with strangers. Traffic on major streets and thoroughfares in 

Rock Springs and Rawlins was often congested (relative to past years), housing prices increased 

substantially, and local retail and service establishments had difficulty obtaining and keeping employees. 

There were enthusiastic supporters of the boom and just-as-ardent detractors in all communities. But even 

some of the supporters lamented the change in social conditions, e.g., “feeling the need to lock their 

houses and take the keys out of their cars, entering a supermarket or restaurant and not seeing a familiar 

face, having to wait for two stoplight cycles to cross an intersection.” For many, these inconveniences 

were offset by the robust economy and the increase in employment and shopping options. Others, 

including those who did not benefit from energy development and those on fixed incomes, were less 

likely to be enthusiastic about the boom. 

Many residents of Carbon and Sweetwater counties value clean air and water, wildlife, wildlife habitat, 

and access to and the health of public lands (Blevins et al. 2004, Carbon County Board of Commissioners 

and Carbon County Planning Commission 1998, Markert 2008). A key concern for many residents is the 

effect of energy development on public lands, particularly lands with high resource values. 

Two groups have been directly affected by natural gas development in the project area: ranchers/grazing 

permittees and recreation users of the area. 

3.15.7.2 Ranchers/Grazing Permittees 

Information for this section was obtained in the spring of 2008 from individual and group interviews with 

grazing permittees, the Rawlins-based UW Cooperative Extension Area Educator for Range 

Management, and the RFO Range Resources Specialist assigned to the CD-C EIS. As discussed in 

Section 3.18 Range Resources, 47 allotments are permitted for grazing within the project area. Many of 

these allotments extend beyond the boundaries of the project area. The active allotments are permitted for 

about 199,000 animal unit months (AUMs) of grazing per year used mostly by cattle, although sheep are 

grazed on 11 allotments. 

Many of the affected livestock operations that use the project area are locally owned, multi-generational 

family ranches. A combination of long-term drought, high fuel and feed prices, unfavorable market 

conditions, and the high level of existing natural gas development within the allotments has resulted in 

challenging times for grazing permittees, causing some to substantially alter their methods of operation 

and even consider relinquishing their allotments. 

In the most active natural gas fields within the project area, the predominant land use has changed from 

grazing/dispersed recreation to industrial. The project area contains roads with some of the highest traffic 

volumes in Carbon and Sweetwater counties, including high volumes of heavy-truck traffic. The high 

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traffic volumes within the project area produce substantial amounts of dust on all but the major roads, 

which have been treated with magnesium chloride. 

Natural gas development can affect grazing operations in several ways. Effects include livestock 

injury/mortality, reduced rates of weight gain in livestock, increased maintenance of range improvements, 

and required changes in livestock management practices. 

Heavy traffic during the drilling and field-development phase often results in conflict with livestock 

operations. Vehicle/livestock collisions are not uncommon and, although some natural gas companies 

compensate permittees for livestock mortality, accidents are not reported in many cases. Responsibility is 

difficult to assign in areas used by multiple gas companies, and some service companies are less willing 

to compensate livestock owners. Companies are, in general, unwilling to compensate grazing permittees 

unless a driver accepts or is assigned responsibility for the accident. Gas-field traffic is of particular 

concern during lambing and calving periods, when animals sometimes use the roads to give birth and 

newborn animals are less able to move out of the way of oncoming traffic. In addition to animal losses 

from accidents, livestock lose weight if they are frequently startled by traffic. Some permittees have 

stopped trailing their herds along WY 789, the Wamsutter–Dad Road, and other major county and BLM 

roads within the project area because of the high volumes of industrial traffic, resulting in higher costs to 

move livestock by truck from pastures on one side of the road to the other. 

High levels of gas-field traffic can increase damages to range improvements such as fences and cattle 

guards, resulting in scattering of livestock from pastures and introduction of other livestock and wild 

horses into pastures. During severe winters, when natural gas company contractors clear snow for some 

distance on either side of road surfaces to remove heavy snow accumulations, damage to cattle guards and 

sections of fence often occurs. As a result, some permittees are unable to use some pastures in the spring, 

which has disrupted grazing patterns and resulted in unbudgeted costs to relocate livestock. Although in 

most cases gas companies compensate grazing permittees for repairing fences and cattle guards, there are 

sometimes disputes over the amount of compensation, the quality of the replacement fences and 

structures, and the timeliness of compensation. It is again difficult to assign responsibility for damage in 

areas where multiple gas and service companies are active; grazing permittees lose the use of the pastures 

while awaiting repairs, which at times requires an extended period to locate and schedule contractors. 

Another concern for livestock grazing permittees is that some gas companies do not notify them in 

advance of starting new development within a federal grazing allotment. Consequently, affected grazing 

permittees do not have advance opportunity to relocate herds to avoid conflict with development. 

Although required by regulation, some drilling contractors do not adequately fence drilling facilities such 

as reserve pits, resulting in livestock injury or mortality. 

New and improved roads are at times beneficial for grazing permittees in that they allow better access to 

pastures and livestock. However, new and improved roads also facilitate higher travel speeds for gas-field 

traffic, increasing the risk of vehicle/livestock accidents. New and improved roads also allow more public 

access into grazing allotments, increasing the potential for vandalism and disruption of grazing in 

formerly remote areas. Some grazing permittees report reductions in vandalism in areas that are actively 

being developed, however, which they attribute to the greater human presence. 

An oft-cited effect of high levels of natural gas development is the reduction in forage associated with 

surface disturbance and infestation of noxious and invasive species when reclamation is delayed or 

unsuccessful. In areas where development is concentrated, reductions in forage can be substantial. 

Although a portion of disturbance for well pads, pipelines, roads, and other ancillary facilities is required 

to be reclaimed within a short period of time, a combination of the prolonged drought and ineffective 

reclamation methods has resulted in drill pads, pipeline and road corridors, lay-down areas, and pads for 

ancillary facilities remaining unreclaimed or in a weed-infested state for years. In addition to the direct 

reductions in forage associated with unreclaimed or weed-infested areas, a substantially larger area is 

often removed from productive use as a result of wind-blown dust from unreclaimed areas and roads 

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which accumulates on plants, reducing palatability and accelerating wear on livestock teeth. The location 

of well pads, gathering lines, and roads may also alter surface-water flow patterns, resulting in erosion 

and loss of vegetative cover and forage. 

The combination of high levels of gas-development activity, reduced forage, and drought conditions 

requires substantially higher levels of livestock management for grazing permittees, as they are required 

to more frequently monitor livestock condition and movements, relocate livestock more frequently, and 

round up livestock that have wandered from pastures when fences and cattle guards are down. 

Sheepherders have been required to avoid grazing and trailing their flocks through certain areas and to 

find new trails to avoid halogeton infestations, which can be toxic to sheep. Some grazing permittees who 

formerly wintered cattle on allotments within the project area have had to truck their herds to other areas 

or other states, in part because of periodic drought years but also in part to avoid natural gas activity 

during winter months when herd management is more difficult. 

Higher levels of livestock management result in higher fuel outlays and labor costs. Fuel costs for grazing 

permittees in the project area can be substantial given the distance to the allotments from communities 

and home ranches. Securing ranch hands in Carbon and Sweetwater counties during the boom years was 

complicated by the regional labor shortage and competition for workers. Some grazing permittees had 

difficulty competing for workers with the traditionally higher wages paid by the energy industry. More 

active livestock management, including frequent movement of livestock from pasture to pasture or 

between allotments to avoid disruptive activity can reduce weight gain in cattle. 

All of the above factors result in higher cost, lower production, and reduced profitability for grazing 

permittees. In addition, although their allotments are less productive because of activity, disturbance, 

weed infestations and drought, their allotment lease fees are not reduced. The reduced profitability is 

likely to change the nature of some CD-C area ranching operations and may result in others leaving the 

ranching business. Grazing permittees interviewed for this assessment reported reductions in herd size, 

potential selling off of herds, and potential relinquishment of BLM leases. 

The ranching economy in Carbon and Sweetwater counties is substantially smaller than the energy 

economy, but reductions in ranching operations would result in adverse changes in economic diversity in 

these two counties. Reductions in ranching operations would also have social and cultural implications for 

the study area. Ranching is an important element of the heritage and culture of Carbon and Sweetwater 

counties and the State of Wyoming as a whole. 

3.15.7.3 Recreation Users of the Area 

Substantial changes in the recreation setting within the project area have already occurred. As noted 

elsewhere in this assessment, an average of about 239 wells/year were drilled within the project area 

during the 2000-2010 period and there were over 3738 producing wells in the area at the end of 2010. 

As discussed in Section 3.12 Recreation, hunting—primarily by locals—is the dominant recreation use 

of lands within the project area. Some pleasure driving to view wild horses or the Red Desert landscape 

occurs near the specific resources and settings of interest. As noted in Section 3.12, the BLM makes 

estimates of recreation usage at the field-office level only, so there are no available data on recreation 

participation and recreation visitor days that are specific to the CD-C project area. Similarly, the WGFD’s 

Hunt Areas extend beyond the boundaries of the project area and the WGFD does not collect statistics for 

sub areas; it is therefore not possible to assign hunter activities specifically to the CD-C project area. 

Consequently, data are not available to support the estimation of economic effects of hunting or other 

recreation activities within the project area. Recreation use in the project area is low overall and seasonal, 

with most occurring in the fall during the big game hunting seasons. The BLM generally considers the 

project area to be a recreation resource that attracts some non-residents who have special interests (e.g., 

wild horses, historic trails, and the Red Desert) but is visited mainly by Wyoming residents, especially 

those living nearby. 

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CHAPTER 3—AFFECTED ENVIRONMENT—SOCIOECONOMICS 

A combination of local residents, residents from elsewhere in Wyoming, and non-residents has 

historically hunted within the project area, although as noted above, locals are the dominant users and the 

level of hunting use is relatively low. Adverse effects of existing natural gas development on hunting 

have resulted from development activity, traffic, and changes in wildlife distribution and abundance. 

Although the current presence of relatively widely spaced wells is not a deterrent for all hunters, safety 

issues associated with hunting around natural gas facilities and the change in the recreational setting are 

believed to be deterrents for many non-local and out-of-state hunters for whom a natural setting is a part 

of the overall hunting experience. Displacement of hunters from the project area could result in increasing 

hunting pressure in other areas. There is increasing concern among hunting and wildlife advocacy groups 

that development in wide expanses of wildlife habitat and migration corridors will have an adverse effect 

on wildlife populations within an area, which could result in a shift in hunting activity away from the 

project area. 

Some local and non-local groups and individuals value specific areas within and adjacent to the project 

area including a sage-grouse lek complex southeast of Creston, the Red Lakes Dunes Citizens’ Proposed 

Wilderness and the Chain Lakes WHMA. At the time of this assessment, one well has been drilled in the 

Chain Lakes WHMA and several wells have been drilled near the part of the Red Lakes Dunes Citizens’ 

Proposed Wilderness and the sage-grouse lek east of Creston. 

A growing concern is the increasing amount of big-game poaching occurring in remote areas now 

accessible on roads improved for natural gas development and an increasing amount of both personal and 

industrial litter along highways and county, BLM, and private roads. These effects represent a loss in 

environmental amenity values for local residents, recreational users, and non-users alike. 

Cumulative effects of energy development on recreation use of the area is discussed in Chapter 5 of this 

EIS, but there is increasing concern among local public officials and residents regarding the direct and 

indirect effects of the intensive level of current and ongoing energy-related development, including oil 

and gas development, pipeline construction, and wind energy and transmission line development across 

southwest Wyoming on the availability and quality of outdoor recreation opportunities and experiences. 

The potential for adverse effects arise in conjunction with changes in recreational setting, visual character, 

noise, dust, increased presence of other humans, changes in vegetation, water quality, and presence of 

wildlife. 

3.15.8 Environmental Justice 

Environmental justice is defined as the fair treatment and meaningful involvement of all people regardless 

of race, color, national origin, or income with respect to the development, implementation, and 

enforcement of environmental laws, regulations, and policies (USEPA 1998). EO 12898, Federal Actions 

to Address Environmental Justice in Minority Populations and Low-Income Populations, published in the 

Federal Register in 1994, tasks “each Federal agency [to] make achieving environmental justice part of its 

mission by identifying and addressing, as appropriate, disproportionately high adverse human health and 

environmental effects of its programs, policies, and activities on minority populations and low-income 

populations.” 

Implementation of EO 12898 for NEPA by agency directive involves the following steps (BLM 2002): 

 Identification of the presence of minority and low-income populations and Indian Tribes in areas 

that may be affected by the action under consideration. 

 Determination of whether the action under consideration would have adverse human health, 

environmental, or other effects on any population.
 

 Determination of whether such environmental, human health, or other effects would be 

disproportionately high and adverse on minority or low-income populations or Indian Tribes.
 

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	 Providing opportunities for effective community participation in the NEPA process, including 

identifying potential effects and mitigation measures in consultation with affected communities and 

improving the accessibility of public meetings, crucial documents, and notices (CEQ 1998). 

The BLM standard for identifying a low-income population is the poverty level used by the U.S. Census 

Bureau. The standard for identifying minority populations is either: 1) the minority population of the 

affected area exceeds 50 percent, or 2) the minority population percentage of the affected area is 

“meaningfully greater” than the minority population percentage in the general population or other 

appropriate unit of geographic analysis. For environmental justice compliance, the relevant minority 

population is the total minority population comprising all persons of a minority racial identity plus 

persons of Hispanic-origin and Latinos (BLM 2002). 

The minority and low-income status of populations within the socioeconomic study area are described in 

the following section. 

3.15.8.1 Racial and Ethnic Minority Populations 

The overwhelming majority of the project area is extremely rural and sparsely settled due to the 

“checkerboard” pattern of alternating sections of public and private land ownership. There are few 

permanently occupied residences within the project area outside of the town of Wamsutter, although some 

ranch facilities and a few rural cabins and privately-owned lots are occupied on a seasonal basis. There 

are no American Indian Reservations, Colonies, or Tribal trust lands in or near the project area. 

Table 3.15-16 compares the percentage of minority residents in the project area, based on data from the 

2010 Census, with that for two counties in which it is located, the state of Wyoming and the nation as a 

whole. The percentages of minorities in Carbon County and Sweetwater County are higher, but not 

meaningfully higher, than the statewide average. Minorities were an estimated 18.7 percent of the 

population in an area that encompasses the project area, essentially the same as the local county averages 

(Carbon County at 20.2 percent and Sweetwater County as 19.1 percent), slightly higher than the 

statewide average, but considerably lower than the national average. The Hispanic or Latino population is 

the single largest minority group, locally as well as across the state. 

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CHAPTER 3—AFFECTED ENVIRONMENT—SOCIOECONOMICS 

Table 3.15-16. Percentage of minorities in the State of Wyoming, Carbon County, Sweetwater 

County, the CD-C project area, and selected communities 

Percentage of Total Population 

(A) (B) ( C) (D) (E) 

Geographic Area 

White and not 

Hispanic or 

Latino 

Total Racial 

Minorities 

and not 

Hispanic or 

Latino 1 

Hispanic or 

Latino 

Ethnicity 

Total Racial 

and Ethnic 

Minorities 

(B) + (C) 

Difference in 

Percent 

Minority 

Population 

Above/Below 

the State 

Average 

United States 62.3% 19.5% 18.2% 37.7% 23.6% 

Wyoming 85.9% 5.2% 8.9% 14.1% 0.0%

 Carbon County 79.8% 3.4% 16.8% 20.2% 6.0%

 Sweetwater County 80.9% 3.8 15.3% 19.1% 5.0%

 Rawlins 71.5% 4.2% 24.3% 28.5% 14.3%

 Rock Springs 79.1% 4.5% 16.4% 20.9% 6.8%

 Wamsutter 74.7% 5.6% 19.7% 25.3% 11.1% 

CD-C project area 

estimate 2 81.3% 3.3% 15.4% 18.7% 4.6% 

1

 Racial minorities includes all persons identifying themselves as a non-white race, including "Black or African American,” 

"American Indian and Alaska Native," "Asian," "Native Hawaiian and Other Pacific Islander," "Some other race alone," 

and "Two or more races.” Ethnic minorities include persons who identify themselves as Hispanic or Latino. 

2 The project area estimate is based on data for several rural census tracts in western Carbon County and eastern 

Sweetwater Counties, including the town of Wamsutter, but excluding Baggs. 

Source: U.S. Census Bureau, 2010. 

When expressed as a share of the total population, the Hispanic population has grown across these two 

counties over the past decade, climbing from 13.8 percent to 16.8 percent of the Carbon County 

population and from 9.4 percent to 15.3 percent of the Sweetwater County population. The analysis area 

does not exactly match the project area boundaries, but has similar demographic characteristics to the 

project area. 

Wamsutter had a 2010 census population of 451, 25.3 percent of whom were identified as racial or ethnic 

minorities. The town exists in large part due to the substantial presence of the energy industry and 

ongoing oil and gas development activity has been largely responsible for the recent population growth. 

Thus, the relatively high share of minorities and the increase in minority population in recent years is 

indicative of growth attracted by economic opportunity, rather than the presence of a minority population 

rising to the BLM standards for consideration from an environmental justice perspective. 

3.15.8.2 Persons in Poverty 

Table 3.15-17 summarizes the prevalence of poverty in the project area and two host counties that 

encompass the project area. For the analysis of low-income population for the year 2000, the local area 

that includes the project area is slightly larger than that for the analysis of minority populations because 

the level of aggregation of income data available from the U.S. Census Bureau is larger than that for 

racial and ethnic characteristics. 

Based upon 2000 Census data, persons with incomes below the poverty level represent 10.6 percent of the 

population in the analysis area that includes the project area, 1.8 percent lower than the 11.4 percent of 

the population with incomes below the poverty level for the State of Wyoming. In comparison countywide poverty in Carbon County was slightly above the national average, while that in Sweetwater County 

was approximately 25 percent lower. In part the latter reflects the strong industrial base of Sweetwater 

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CHAPTER 3—AFFECTED ENVIRONMENT—SOCIOECONOMICS
 

County, while the former is influenced by the location of a relatively large inmate population at the 

Wyoming State Penitentiary in Rawlins. 

Detailed poverty data are not yet available from the 2010 Census. However, poverty estimates prepared 

by the Census Bureau for 2009 indicate a reduction in poverty rates in Wyoming and Carbon and 

Sweetwater counties, as compared to those for 2000. Meanwhile, poverty rates rose at the national level 

for the same two points in time. The median household income for Carbon and Sweetwater counties also 

exceeded the national average, with that for Sweetwater ranking among the top 5 percent within the 

nation. Estimates for 2009 are not available for Wamsutter, but the relatively high rates of employment— 

much of it in energy-related jobs—that characterize the community are thought to be unlikely to result in 

poverty rates substantially higher than the statewide or national averages. 

Table 3.15-17. Poverty levels in the United States, State of Wyoming, Carbon County, and Sweetwater 

County, 2000 and 2009 

Geographic Area 

Share of Population 

Below Poverty Level 

2000 

Share of Population 

Below Poverty Level 

2009 

Median 

Household Income 

2009 

United States 12.4% 14.3% $50,221 

Wyoming 11.4% 10.2% $54,400

 Carbon County 12.9% 11.7% $50,353

 Sweetwater County 7.8% 7.3% $69,297 

CD-C project area estimate 10.6% Not Available Not Available 

Source: U.S. Census Bureau, 2002 and U.S. Census Bureau, 2010. 

The communities of Rawlins, Rock Springs, Green River, Baggs, Sinclair, and other small settlements are 

outside the project area, spatially separated from the project by topography. Consequently, these 

communities are not considered likely to be affected from an environmental justice perspective. 

The foregoing analysis supports the finding that the low-income population in the project area does not 

rise to the BLM standards for consideration from an environmental justice perspective. 

3.16 TRANSPORTATION AND ACCESS 

The primary transportation access to and within the CD-C project area is via highway, although the Union 

Pacific mainline railroad across southern Wyoming passes through the project area on a generally eastwest route. General aviation and commercial service-capable airports are located in Rock Springs and 

Rawlins, with several other general aviation and private airfields in the surrounding region. 

Interstate Highway 80 (I-80) and WY 789 provide primary highway access to the project area. Most 

traffic destined for the project area originates in Rock Springs, Rawlins, Wamsutter, or Baggs, making I80 and WY 789 the most direct and commonly used highway access routes. Highway access routes are 

shown in Map 3.16-1. I-80 bisects the project area and provides access to a number of county and BLM 

roads that in turn access both the north and south parts of the project area. WY 789 provides access to the 

existing gas fields to the east and west of the highway and has seen substantial increases in traffic during 

the last several years attributable to natural gas development and interstate pipeline construction. 

Although it is possible to reach the project area from US 287 to the east, this route is seldom used because 

of the distance and the connecting roads; these roads are not as direct and are not maintained for gas-field 

traffic. US 287 provides access to I-80 for gas-field traffic coming from Casper and other points of origin 

north of the project area. 

Access within the project area is provided by an established network of Sweetwater and Carbon County 

numbered and maintained roads, improved and unimproved BLM roads, and private roads. The BLM 

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CHAPTER 3—AFFECTED ENVIRONMENT—TRANSPORTATION AND ACCESS 

categorizes roads based on existing use or anticipated traffic volumes, seasonal or year-round use, design 

vehicle (types of vehicles most frequently using the road), soil types, weather conditions, topography, 

construction costs, compatibility with other resource values, and safety (USDOI and USDA 2006). BLM 

road types include the following: 

	 Collector roads serve large land areas and are the major access routes into development areas with 

high average daily traffic rates. They are usually double-lane, graded, drained and surfaced, with a 

20- to- 24-foot travelway. They usually connect with public highways or other arterials to form an 

integrated network of primary travel routes and are operated for long-term land and resource 

management purposes and constant service. The locations and standards are often determined by a 

demand for maximum mobility and travel efficiency rather than a specific resource management 

service. 

	 Local roads provide access to large areas and for various uses. They collect traffic from resource or 

local roads or terminal facilities and are connected to arterial roads or public highways. The location 

and standards for these roads are based on both long-term resource needs and travel efficiency. 

Local collector roads may be single-lane or double-lane with travelways 12 to 24 feet in width and 

‘intervisible turnouts,’ where approaching drivers have a clear view of the section of road between 

the two turnouts and can pull off to the side to let the approaching driver pass. They are normally 

graded, drained, and surfaced and are capable of carrying highway loads. They may be operated for 

either constant or intermittent service, depending on land use and resource management objectives 

for the area being served. 

	 Resource roads are low-volume, single-lane roads. They normally have a 12- to14-foot travelway 

with intervisible turnouts, as appropriate. They are usually used for dry weather, but may be 

surfaced, drained, and maintained for all-weather use. These roads connect terminal facilities, such 

as a well site, to collector, local, arterial, or other higher-class roads. They serve low average annual 

daily traffic (AADT) and are located on the basis of the specific resource activity need rather than 

travel efficiency. 

Within the project area, an existing network of collector and local roads has been developed or improved 

to accommodate the already high level of natural gas development and operations-related travel, which is 

the dominant use of these roads. In several cases Carbon and Sweetwater county roads serve the function 

of collector roads and have been improved by the respective county to accommodate that use. Within the 

project area, Sweetwater County Road (SCR) 23S/Carbon County Road (CCR) 701—known as the 

Wamsutter/Dad Road—serves as a collector road for the portion of the field south of I-80; SCR 23N, 

SCR 67, and BLM Road 3207 serve as collector roads for the part of the field located north of I-80. 

3-190 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
CHAPTER 3—AFFECTED ENVIRONMENT—TRANSPORTATION AND ACCESS 

Map 3.16-1. Highway and county road access to and within the CD-C project area 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 3-191 
CHAPTER 3—AFFECTED ENVIRONMENT—TRANSPORTATION AND ACCESS 

The Operators have in some cases improved local roads on BLM and private lands to accommodate their 

level of use and they provide ongoing maintenance for those roads and for resource roads that they have 

constructed on BLM and private lands. 

3.16.1 Current Government-Industry Transportation Planning Efforts for the Project 

Area 

Currently, a transportation plan (TP) and transportation planning committee (TPC) are in place for the 

Continental Divide portion of the project area; there is no TP or TPC for the Creston portion of the project 

area. 

The BLM, the WYDOT, Carbon and Sweetwater Counties, and a number of companies operating within 

the Continental Divide/Wamsutter II Oil and Gas project area developed a Memorandum of 

Understanding (BLM MOU NO. WY 951-99-06-102) to establish a process for dealing with road issues. 

The MOU was intended to: 

“...establish a process through which governmental agencies, oil and gas companies, private 

landowners and other interested parties can meet together to discuss road-related concerns resulting 

from project development, to identify potential solutions to problems, and to develop 

implementation strategies for transportation. The primary focus of this MOU centers on issues 

related to transportation planning including road use, development, maintenance and reclamation.” 

The MOU and the recommendations of the Transportation Planning Technical Support Document for the 

Continental Divide/Wamsutter II Natural Gas Project (BLM 1999a) resulted in the formation of a TPC for 

the CD/WII project area. Since the signing of the MOU in late 1998 and early 1999, the TPC has held 

semi-annual meetings to address transportation issues. Recently the scope of these meetings has been 

expanded to include operators in other areas of the RFO and cover other issues such as reclamation. 

3.16.2 Highway Access to the Project Area 

As noted above, two highways provide access to the project area: I-80 and WY 789 (see Map 3.16-1). I80 bisects the project area horizontally and provides access to a number of county and BLM roads that in 

turn access both the north and south parts of the project area. WY 789 provides access to the existing gas 

fields to the east and west of the highway and has seen substantial increases in traffic during the last 

several years attributable to natural gas development and interstate pipeline construction. US 287 travels 

north from Rawlins at some distance from the project area and at present is used for access to I-80 rather 

than direct access to the project area. 

WYDOT limits access to state highways to every one-half mile and encourages industrial developers to 

use main access points where possible. WYDOT also requires roads accessing state highways to be paved 

to the limits of the highway right-of-way and encourages developers to gravel roads for one-half mile 

before their intersection with state highways to allow trucks to shed mud from tires before entering the 

highway. WYDOT is currently monitoring traffic volumes on WY 789 to determine whether turn-lanes 

are needed at major gas-field road intersections. 

The underpasses associated with off-ramps at the I-80 interchanges through the project area were not 

designed to accommodate over-height or over-width loads. Over-height/over-width loads traveling on I80 that need to access areas on the opposite side of the highway must travel beyond the desired off-ramp, 

cross the median, and return in the opposite direction to the desired off-ramp. This maneuver requires 

three Wyoming Highway Patrol troopers to provide traffic safety services. As many as 13 over-height 

vehicles required use of this maneuver on one day during 2007, the peak year for drilling activity, 

effectively requiring a detail of three Wyoming Highway Patrol troopers for a full day (Griesbach 2007). 

WYDOT measures AADT (annual average daily traffic) and collects accident statistics on federal and 

state highways. Table 3.16-1 displays AADT data for segments of I-80 that provide access to the project 

3-192 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
CHAPTER 3—AFFECTED ENVIRONMENT—TRANSPORTATION AND ACCESS 

area for 1999 and 2009 and WYDOT’s AADT forecasts for 2020 and 2030 based on extrapolations of 

long-term trends. Included in the 2009 AADT is an estimated project area-related AADT of 1,060 

(including an AADT of 299 trucks) associated with the drilling of 244 wells in 2009 and operations 

activities associated with 3,738 producing wells in that year. 

During the 10-year period between 1999 and 2009, increases in total AADT on the I-80 segment between 

Rawlins and Rock Springs (both directions) ranged from 8 percent on the east side of Rock Springs to 16 

percent at the west side of Rawlins. Increases in total truck AADT during the 10-year period were more 

modest, ranging from 2 percent on the west side of Rawlins to 5 percent at Wamsutter. 

AADT increased substantially on WY 789 from I-80 at Creston Junction south to Baggs. South of the 

WY 789/I-80 junction, the combined AADT traveling in both directions increased by 49 percent and 

truck AADT increased by 98 percent during the during the 1999 to 2009 period. Just north of Baggs at the 

junction of WY 789 with CCR 700, which provides access to the Creston part of the project area, overall 

AADT increased by 86 percent and truck AADT increased by 167 percent over the 10-year period. 

As noted, US 287 connects Rawlins and I-80 with Casper and I-25. Total AADT on US 287 north from 

Rawlins to Lamont increased during the 1999–2009 period; total traffic at the US 287 bypass on the north 

side of Rawlins increased by 106 percent but truck AADT increased by a more modest 6 percent. AADT 

south of Lamont increased by 9 percent and truck AADT decreased by 6 percent during the 10-year 

period. 

Although 2009 was chosen to show most-recently available traffic statistics on the affected highways, 

traffic increases on a particular highway segment can be more dramatic as a result of industrial activities. 

For example, increases on WY 789 were more substantial between 1997 and 2007, the peak development 

year; ranging from an increase in total AADT of 76 percent and an increase in truck AADT of 156 

percent south of Creston Junction and an increase in total AADT of 199 percent and an increase in truck 

AADT of 225 percent north of Baggs at the junction with CCR 700. The high level of traffic in this area 

during 2007 was attributed in part to interstate pipeline construction traffic 

WYDOT assigns level of service (LOS) ratings to highways in the state system. LOS A through LOS F 

are assigned based on qualitative measures (speed, travel time, freedom to maneuver, traffic interruptions, 

comfort and convenience) that characterize the operational conditions within traffic streams and the 

perceptions of those conditions by motorists. LOS A represents the best, or free-flowing, travel conditions 

and LOS F represents the worst, or total stoppage of traffic flows. During 2008, the most recent year for 

which LOS ratings were calculated, I-80 through the project area operated at a LOS rating of A and WY 

789 operated at a LOS rating of B, except for the intersection with Carbon County Road 700 West, which 

operated at a LOS rating of C. US 287/WY 220 north from Rawlins to Casper operated at LOS B or LOS 

C, depending on the highway segment. 

WYDOT forecasts for 2030 indicate that traffic conditions on I-80 from Rawlins west to Rock Springs 

will remain at LOS A, except for the segment around the intersection with WY 789 at Creston Junction, 

which will fall to a LOS B. Conditions on WY 789 from Creston Junction south to Baggs will remain at 

LOS B except for the intersection with Carbon County Road 700 West, which will remain at LOS C. US 

287/WY 220 north to Casper is forecast to operate at LOS C for its entire length in 2030 (Brown 2011). 

As shown in Table 3.16-1, traffic is forecast to increase substantially on all highways providing access to 

the project area by 2020 and 2030, with the exception of US 287 at the Rawlins bypass, where total 

AADT is forecast to decline in both 2020 and 2030 and on WY 789 at the junction with CR 700, where 

truck traffic is forecast to decline. 

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CHAPTER 3—AFFECTED ENVIRONMENT—TRANSPORTATION AND ACCESS 

Table 3.16-1. AADT on highways providing access to the CD-C project area: 1999, 2009, 2020, and 2030 

Highway 

Segment 

(Both 

Directions) 

1999 2009 Projected 2020 P

All 

Vehicles Trucks 

All 

Vehicles Trucks 

1999– 

2009 

Increase 

All 

Vehicles 

1999– 

2009 

Increase 

Trucks 

All 

Vehicles Trucks 

2009– 

2020 

Increase 

All 

Vehicles 

2009– 

2020 

Increase 

Trucks 

All 

Vehicles Tru

I-80 Rawlins W. Urban Limits 

11,320 6,370 13,078 6,495 16% 2% 15,342 8,992 17% 38% 17,539 10

Creston Jct. 10,670 6,170 12,225 6,368 15% 3% 14,915 8,740 22% 37% 17,142 10

Continental Divide Int. 10,650 6,170 11,973 6,443 12% 4% 14,880 8,750 24% 36% 17,130 10

Wamsutter 10,650 6,170 12,014 6,458 13% 5% 14,938 8,747 24% 35% 17,211 10

Red Desert 10,630 6,170 11,563 6,332 9% 3% 14,806 8,722 28% 38% 17,063 10

Tipton 10,590 6,170 11,493 6,287 9% 2% 14,858 8,640 29% 37% 17,132 10

Table Rock 10,650 6,170 11,693 6,314 10% 2% 15,054 8,782 29% 39% 17,365 10

Rock Springs E. Urban Limits 

12,710 6,770 11,678 6,498 8% -4% 16,715 9,374 22% 44% 18,949 11

WY 789 Creston Jct. 850 160 1,265 316 49% 98% 1,501 377 19% 19% 1,731 Jct CCR 700 West 970 160 1801 427 86% 167% 1,874 411 4% -4% 2,174 

US 287 Rawlins N. at US 287 Bypass 

2,550 740 5,241 786 106% 6% 4,419 962 -16% 22% 5,046 1

Jct Rte 46 Lamont 2,110 660 2,303 620 9% -6% 2,722 862 18% 39% 3,000 

Source: WYDOT 2009 VMB 

3-194 Continental Divide-Creston Natural Gas Development Project D
 

CHAPTER 3—AFFECTED ENVIRONMENT—TRANSPORTATION AND ACCESS 

3.16.3 Motor Vehicle Crash Statistics on Highways Providing Access to the Project Area 

Figures 3.16-1 and 3.16-2 display data for crashes on highway segments providing access to the project 

area. As shown in Figure 3.16-1, crashes on I-80 between Rawlins and Rock Springs averaged between 

300 and 400 per year between 1998 and 2004, decreasing to 263 in 2005 and then more than doubling to 

529 in 2006 and 536 in 2008 before decreasing to 343 in 2010. An average number of 370 crashes per 

year were reported in the 13-year period from 1998–2010. Until recently, WYDOT calculated crash rates 

for highways based on a formula that considered the type of highway, number of crashes and vehicle 

miles on the highway.18 The 13-year average crash rate for the segment of I-80 between Rawlins and 

Rock Springs was 0.83, which was lower than the 1998–2007 statewide average for crashes on all 

Functional Class 1–Rural Interstate highways (1.10). 

315 

315 

390 383 

318 

409 

321 

263 

529 

454 

536 

371 

343 

0 

100 

200 

300 

400 

500 

600 

700 

I- 80 Rawlins to Rock Springs 

Figure 3.16-1. Annual number of crashes on I-80 between Rawlins and Rock Springs: 1998–2010 

Source: WYDOT/Carpenter 2007and 2008. 

Figure 3.16-2 displays annual crashes for the 1998–2010 period on WY 789 and on US 287 north of 

Rawlins. The number of annual crashes on WY 789 was generally 20 to 30 for the 13-year period except 

during 2006–2008 when the level increased to about 40 crashes. The 13-year average crash rate for WY 

789 was 1.43, slightly below the 1998–2007 statewide crash rate for all Functional Class 6–Minor 

Arterial Highways (1.64). 

The annual number of crashes on US 287 between Rawlins and Lamont ranged from 17 to 33 between 

1998 and 2006, climbing to 42 in 2007 and 2008. The number of crashes then dropped to 8 in 2010. The 

13-year average crash rate for the segment of US 287 between Rawlins and Lamont was 1.21, lower than 

the 1998–2007 statewide average for all Functional Class 02–Principal Arterial Highways (1.31). 

18 During the course of this assessment, WYDOT changed to a safety index that uses injury severity and fatal crashes as part of the 

weighting. Consequently the statewide crash rates for 2008 – 2010 highway functional classes were not calculated. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 3-195 
CHAPTER 3—AFFECTED ENVIRONMENT—TRANSPORTATION AND ACCESS 

0 

5 

10 

15 

20 

25 

30 

35 

40 

45 

50 

WY 789 Creston Junction to Baggs US 287 Rawlins to Lamont 

Figure 3.16-2. Annual number of crashes on WY 789 between Creston Junction and Baggs and 

on US 287 between Rawlins and Lamont: 1998–2010 

Source: WYDOT/Carpenter 2007, 2008 and 2010 

3.16.4 County Roads 

Numbered and maintained Carbon and Sweetwater County roads that provide access to and within the 

project area are shown in Map 3.16-1. Other roads that are not numbered or maintained but which may 

fall under the definition of Public Roads as defined by U.S Revised Satute R.S. 2477—commonly known 

as R.S. 2477—are not specifically identified on the map. Most of the numbered and maintained county 

roads displayed on the map were originally developed for grazing and recreational uses but have evolved 

to become primarily natural gas industry access roads. This change in use, both in terms of volume and 

load, has resulted in substantial investments of time, equipment, materials, and funds by the counties to 

substantially reconstruct and maintain the affected roads. 

3.16.4.1 Carbon County 

Carbon County maintains about 1,000 miles of county roads. Only one Carbon County road is located 

within the project area: CCR 701, the Wamsutter–Dad Road. 

CCR 701 (Wamsutter–Dad Road) provides access to the project area from WY 789 at Dad. Traveling 

north, the road becomes SCR 23S at the Sweetwater County line and provides access to the Town of 

Wamsutter and I-80 to the north. CCR 701 is by far the busiest road in Carbon County. The road is a 

19.5-mile-long crowned-and-ditched, two-lane gravel road with a 24-foot-wide driving surface. Initially 

developed to serve ranching and grazing operations in the area, the road has been improved to 

accommodate the 24-hour/day, 365-day/year industrial level of use that it now receives. CCR 701 is in a 

constant state of maintenance, repair, and improvement. During 2006, the Carbon County Road and 

Bridge Department (CCRBD) completed a $1.2 million reconstruction of the road including 6–8 inches of 

gravel and one-half gallon of magnesium chloride dust-suppressant per square yard of gravel. Given the 

constant, high level of heavy and overweight vehicle use on CCR 701, portions of the road must be 

reconstructed every year. In 2008, the CCRBD applied additional gravel to the road along with one3-196 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
 

CHAPTER 3—AFFECTED ENVIRONMENT—TRANSPORTATION AND ACCESS 

quarter gallon of magnesium chloride per square yard of gravel. This process was repeated in 2009 along 

with reclamation of gravel pushed to the roadside during the preceding two years. According to the 

CCRBD Superintendent, the benefits of the annual gravel/magnesium chloride applications are becoming 

evident as the program proceeds (Nation 2007). 

The lack of a nearby source of suitable gravel with the proper mixture of rock and binder, high fuel costs, 

and the need for water for construction, road stabilization, and dust suppression are among the challenges 

that the CCRBD faces in constructing and maintaining county roads. In some cases, the Operators and 

landowners have cooperated with the county to provide gravel and water for road reconstruction and 

maintenance. 

Vehicle travel speed, particularly that associated with heavy trucks, is a key issue for road maintenance 

and safety on county roads. During 2007, the CCRBD and Sheriff’s Department conducted a speed index 

survey on CCR 701. As a result of the survey, the Sheriff’s Department established a speed limit of 45 

miles per hour (mph) on the road and 30 mph for some curves. The Sheriff’s department monitors speed 

on CCR 701 and issues summons for speed-limit violations (Morris 2007). 

3.16.4.2 Sweetwater County Roads 

Sweetwater County maintains about 1,200 miles of roads and 23 bridges. Sweetwater County roads 

providing access to and within the project area include SCR 23, 20, 67, 80, and 55. These and all 

Sweetwater County roads that serve oil and gas industry activities are under a continuous maintenance 

program that includes grading and spot gravel replacement and accounts for about 77 percent of the 

Sweetwater County Road and Bridge Department’s (SCRBD) annual budget (Gibbons 2007, Radosevich 

2007). 

	 SCR 23S (Wamsutter–Crooks Gap Road South) is an 8.2-mile, 24-foot-wide gravel and nativematerial road that provides access from I-80 and Wamsutter to the north and connects with CCR 

701 to the south to form a continuous road to WY 789 at Dad. SCR 23S is a heavily traveled 

industrial road. During 2007, SCRBD conducted a traffic study at a point 0.5 miles south of the 

Wamsutter overpass on SCR 23S and counted a total of 11,729 vehicles during a 72-hour period, 

which averages about 3,910 trips/day for those three days. The SCRBD overlaid six miles of the 

road with gravel and magnesium chloride during 2007 and the remainder of the road in 2008. 

	 SCR 23 N (Wamsutter–Crooks Gap Road North) is a 44.5-mile, 24-foot-wide gravel and nativematerial road that travels north from I-80 and Wamsutter to the Sweetwater County line. The road is 

paved for the first half-mile north of Wamsutter. The 2007 SCRBD traffic study counted 2,792 

vehicles in a 72-hour period on the road or a daily average of 931 trips for the three-day period. 

	 SCR 67 (Tipton North Road) is a 24-foot-wide gravel and native-material road that travels north 

from I-80 at Tipton to a point north of Luman Butte, just outside the northwest corner of the project 

area. This route is divided into two segments. The first segment travels 25 miles north from I-80 to 

SCR 20, merges with SCR 20 (Luman Road) and travels west for about one mile, and then travels 

about 10 miles north of SCR 20. 

	 SCR 20 (Luman Road) is a 28.3-mile, 20-foot-wide native-material road that travels west from 

SCR 23 at about mile 13 near Denison Gap, crosses SCR 67 at mile 25.5 and proceeds westward to 

connect with SCR 21 about 3.5 miles west of the project area boundary. 

	 SCR 46 travels west from WY 789 about one mile south of I-80 for approximately 2 miles, 

paralleling the Union Pacific railroad right-of-way to the former Creston Siding.
 

	 SCR 80 (Tipton Station Road) is a 0.8-mile, 15-foot-wide native-material road that travels south 

from I-80 at Tipton and connects with an unnamed BLM road that provides access to lands along 

the southwestern boundary of the project area. 

	 SCR 55 (Table Rock Road) is a 4.6-mile, 20-foot-wide native-material road that provides access 

from I-80 to a small portion of land at the extreme western border of the project area. 

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CHAPTER 3—AFFECTED ENVIRONMENT—TRANSPORTATION AND ACCESS 

3.16.5 BLM Roads 

A number of BLM-designated roads provide access within the project area (Map 3.16-2). BLM has rightof-way agreements for all private lands crossed by three of the roads; other BLM numbered roads within 

the project area do not have right-of-way agreements in place for all the private lands crossed. Operators 

who need to use these roads to access leases must obtain their own right-of-way agreements with private 

landowners. Agency maintenance of BLM roads is relatively minimal; the RFO has one road-grader for 

1,700 miles of roads in the RFO area. In some cases the operators maintain heavily used segments of 

BLM roads. 

Most of the BLM-designated roads used to access natural gas development and production areas within 

the project area were not designed or constructed to accommodate heavy truck traffic and continuous allweather use. As noted above, operators often improve and maintain roads that access development and 

production areas and some have developed agreements with private landowners for road improvement 

and maintenance. Dust, excessive speed, conflicts with livestock, and damage to grazing improvements 

such as fences, gates, and cattle guards are frequent problems within the project area (Miller 2007). 

3.16.5.1 BLM Roads with Right-of-Way Agreements 

 BLM Road 3207 (Red Desert Road) provides access to the north-central portion of the project 

area from I-80 at Red Desert. The road extends about 18 miles north towards the Lost Creek Basin. 

 BLM Road 3316 (Robbers Gulch Road) travels west from WY 789, providing access into and 

across the southern portion of the project area about 15 miles north of Baggs. 

 BLM Road 3321 (Little Robber Road) travels west from WY 789 for about five miles and 

provides access into the southern portion of the project area about 11 miles north of Baggs. 

3.16.5.2 BLM Roads Without Full Right-of-Way Agreements 

	 BLM Road 3202 (Stratton Road) traverses the northeast corner of the project area for about 9 

miles, connecting with BLM Road 3203 to the west and exiting the project area to the east. 

	 BLM Road 3203 (Riner Road) provides access to the northeast side of the project area from I-80 

at Riner, about 14 miles east of Rawlins. The road extends about 10 miles to the northwest from I80 before it enters the project area and then travels another 15 miles to the northwest before exiting 

the project area. Currently the road is not heavily used by gas industry traffic; rather it primarily 

provides access for ranchers, grazing operators, and recreation users of the area. 

	 BLM Road 3205 (Continental Divide Road) travels northwest from I-80 at Continental Divide, 

intersecting with SCR 23N near the northern boundary of the project area. BLM 3205 also intersects 

with BLM 3239 about 10 miles from its beginning. 

	 BLM Road 3206 (Mineral X Road) provides access east from SCR 23N to the Monument Lake 

area of the north-central project area, connecting with BLM 3205. 

	 BLM Road 3208 (Lost Lake Road) travels northeast from its origin on SCR 20 in the 

northwestern portion of the project area for about five miles to its intersection with BLM 3237, 

which then exits the project area.
 

	 BLM Road 3209 (Tipton Road) connects SCR 20 to SCR 67 just below Horseshoe Bend in the 

northwestern part of the project area, a distance of about 3 miles. 

	 BLM Road 3210 (Eagle’s Nest Road) connects SCR 23N with BLM Road 3219 in the 

northwestern portion of the project area. For most of its length, BLM 3210 is outside the northern 

boundary of the project area. 

3-198 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
CHAPTER 3—AFFECTED ENVIRONMENT—TRANSPORTATION AND ACCESS 

Map 3.16-2. BLM roads within the CD-C project area 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 3-199 
CHAPTER 3—AFFECTED ENVIRONMENT—NOISE 

	 BLM Road 3211 (Larsen Knoll Road) travels northeast for about 3 miles from its origin on BLM 

Road 3203 in the northeastern portion of the project area and then exits the project area. 

	 BLM Road 3215 (Sooner Road) travels north from its origin at BLM Road 3203 in the northeast 

corner of the project area and exits the project area within several miles. 

	 BLM Road 3218 (Creston Junction Road) travels north from I-80 at Creston Junction and travels 

about 8 miles north, exiting the project area on the eastern boundary. 

	 BLM Road 3219 (Red Creek Road) extends northeast from SCR 67 in the northwest corner of the 

project area and travels about 10 miles to an intersection with BLM 3210 and then exits the northern 

boundary of the project area. 

	 BLM Road 3224 (Cronin Draw Road) travels west from its origin at SCR 67 in the extreme 

northwest corner of the project area, exiting the project area within several miles. 

	 BLM Road 3233 (Bush Lake Road) travels north from its intersection with SCR 67, just north of 

Luman Ranch and exits the project area several miles to the north. 

	 BLM Road 3237 (Government Reservoir Road) travels northwest from its origin on SCR 23, 

providing access to the Lost Creek Butte area in the far north central portion of the project area 

	 BLM Road 3239 (Chain Lakes Rim Road) originates at BLM 3205 about 10 miles north of I-80 

and travels to the east for about 8 miles, intersecting with BLM 3203 and providing access to the 

Chain Lakes area. 

	 BLM Road 3302 (Divide Road) extends east from WY 789 about 7 miles south of Creston 

Junction and provides access to the eastern border of the project area. 

	 BLM Road 3304 (Eight Mile Lake Road) provides access to the Creston/Blue Gap area on the 

west side of WY 789, terminating to the west at CCR 701 just south of its starting point at the 

Sweetwater County line. 

	 BLM Road 3310 (Barrel Springs Road) intersects SCR 23 about 7 miles south of Wamsutter and 

provides access to the southwest area of the project area. 

	 BLM Road 3313 (Delaney Rim Road) provides access from I-80 at Tipton to the southwestern 

part of the project area. The road travels about 5 miles south and then travels east along the south 

and east sides of the Delaney Rim for about 16 miles. 

	 BLM Road 3315 (Standard Road) travels west about 6 miles from its intersection with WY 789 

about 2 miles south of Dad, providing access to the Blue Gap area. 

	 BLM Road 3317 (Windmill Draw Road) travels north from BLM Road 3315 to connect with 

several unnamed roads on the western edge of the project area. 

	 BLM Road 3323 (Red Desert Road South) extends south into the project area from I-80 at Red 

Desert. The road travels about 11 miles and provides access to the east side of the Delaney Rim and 

Barrel Springs Draw areas. 

	 BLM Road 3326 (China Butte Road) travels northeast for about 3 miles from its origination at 

WY 789 about 9 miles north of Dad, skirting Baldy Butte on the west and exiting the eastern 

boundary of the project area. 

	 BLM Road 3335 (Echo Springs Road) travels southeast for about 11 miles from its origin on SCR 

23S just south of Wamsutter to its intersection with BLM Road 3304. 

	 BLM Road 3336 (Eureka Headquarters Road) travels for about 10 miles southwest from its 

intersection with CCR 701 about 3 miles southeast of the Sweetwater County line, providing access 

to the Barrel Springs area. 

	 BLM Road 4410 [not shown on map] originates at SCR 55 about 2.5 miles south of I-80 in the 

western portion of the project area and travels south, exiting the project area in about 1.5 miles. 

3-200 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
CHAPTER 3—AFFECTED ENVIRONMENT—TRANSPORTATION AND ACCESS 

3.16.6 2007 Drilling and Production Traffic 

Based on the per-well drilling/field-development and production operations factors used for the 

transportation assessment (Section 4.16), it is estimated that during 2009, a total AADT of 1,525 

(including an AADT of 629 trucks) was generated by natural gas drilling and production activities within 

the project area. As noted in Section 3.16.3, an estimated total AADT of 1,060 traveled on highways 

providing access to the project area and the remainder occurred on county, BLM, and private roads within 

the project area. 

3.17 NOISE 

The common measure of noise in the United States is the A-weighted sound pressure level that measures 

noise in decibels (dBA). The EPA-established standard for acceptable environmental noise is 55 dBA. 

Noise levels greater than 55 dBA may disturb local residents and recreationists and could displace area 

wildlife. The degree of disturbance depends on the receptor’s distance from the source, noise intensity 

and duration, as well as the sensitivity of the receptor. 

The human ear is more sensitive to sound in the frequency range 1 to 4 kilohertz (kHz) than to sound at 

very low or high frequencies (EngineeringToolBox.com 2011). An A-weighting filter de-emphasizes low 

frequencies or pitches and therefore is less sensitive to very high and very low frequencies. Very high 

sound levels are more appropriately measured using the C scale. Measurements made on this scale are 

expressed as dBC (University of New South Wales 2011); C filters are seldom used (EngineeringToolBox.com 2011). Animals tend to hear sound at frequencies that humans cannot; the C-weighted decibel 

scale may be appropriate for evaluating effects of some sounds on other species. For example, dogs hear 

noises up to 45 kHz, while humans only hear sounds up to about 23 kHz. This means that they could be 

hearing and responding to sounds that humans cannot hear at all. Cats can hear sounds as high as 64 kHz, 

bats up to 110 kHz, and porpoises up to 150 kHz (DOE 2011). 

Median noise levels for the project area likely range from 20 to 40 dBA in the morning and evening and 

from 50 to 60 dBA in the afternoon when wind speeds are typically greatest. These levels correspond to 

noise levels of a soft whisper (30 dBA), a library (40 dBA), a quiet office (50 dBA), a small town (40–50 

dBA), and a normal conversation (60 dBA). Additional noise comes from aircraft, traffic on county roads 

and state highways, operation of the existing gas compression stations, natural gas drilling and production 

areas, and transportation (railroad and interstate highway) corridors. Existing noise levels within the 

project area are for the most part representative of rural conditions and are expected to be between 35 and 

45 dBA (Harris 1991), except near county roads and compressor stations where noise levels may be as 

high as 65 dBA. Noise may exceed 70 dBA in close proximity to specific pieces of equipment or 

operations (Table 3.17.1). 

The BLM measured various aspects of development operations in the Jonah Field in western Wyoming 

and found flaring activities to be the loudest source of noise followed by drilling operations and 

compression. At 0.25 miles from the activity, noise was reduced to below the 55 dBA level (BLM 

2006b). Mitigation measures such as hospital-grade mufflers on compressors and flowback separators on 

high-intensity flaring operations aid in reducing noise to acceptable levels. Noise levels from traffic along 

the interstate typically average greater than 70 dBA (BLM 2005d). Blickley and Patricelli (2010) provide 

the following insight relative to noise generated by human activities: “Most anthropogenic noise sources 

have energy concentrated in low frequencies (<250 Hz), which can travel long distances with relatively 

little energy loss. Such noise is also more difficult to control using traditional noise-abatement structures, 

such as noise reflecting or absorbing walls along highways or surrounding other fixed noise sources, such 

as industrial sites.” 

The 2009 Pinedale Anticline project area noise study (KC Harvey 2009) found noise levels at various 

sage-grouse lek locations in the Pinedale natural gas field to be in general compliance with the BLM 

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CHAPTER 3—AFFECTED ENVIRONMENT—RANGE RESOURCES 

stipulation requirements, as follows: “Average measured noise levels are all below the 10 dBA above 

background threshold level of 49 dBA. Two locations had noise levels below baseline, and the highest 

level was 47.4 dBA. Median noise levels are also below 49 dBA level at all measured locations.” Their 

observations continued, “Field personnel maintaining the noise meters noticed that windy conditions 

increased noise levels noticeably, sometimes to greater than 50 dBA. Since windy conditions are common 

in the area, wind noise may contribute significantly to the background noise levels (KC Harvey 2009).” It 

can be anticipated that the project area could have similar wind conditions. 

The majority of the compressor stations in the CD-C project area may already meet the recommended 55 

dBA (with an average day/night noise level of 49 dBA) for noise impacts to sensitive receptors at 0.25 

mile (1,320 feet) from the source (Schomer 2005). This standard is commonly applied by the BLM to 

compressor stations within oil and gas development projects (BLM 2003). 

Table 3.17-1. Typical noise measurements from common energy development-related sources in the 

CD-C project area 

Description HP dB(A) dB(C) 

Two (2) Cat 3516 with noise wall 1,000 45 ---

Two (2) Cat 3516 without noise wall 1,000 50 ---

Two (2) Waukesha H24 and F18 compressor engines --- 75 ---

Two (2) Electric driven compressors --- 65 ---

One (1) Ajax Cooper 2802 250 51 ---

One (1) Ajax Cooper 2803 compressor engine 400 52 ---

One (1) Cat or Waukesha compressor engine 1,200 75 ---

One (1) Cat or Waukesha with high-performance intake and exhaust silencers 1,200 70 ---

One (1) Waukesha 5794LG- compressor engine; fan end 1,000 91 95 

One (1) Cat 3516 compressor engine; fan end, quiet fan 1,000 63 

One (1) Dehyd boiler 15 52 ---

One (1) Cummins electric generator skid unit 1,000 69 ---

One (1) Cat 3608 compressor engine w/ 2 heat exchangers --- 79 ---

One (1) Disposal-well pump building with electric motors inside --- 53 ---

One (1) Cat 3608 compressor engine 1,000 58 ---

One (1) Drill rig (Jonah Field) --- 69 

One (1) Ajax/Cooper compressor engine with weather cover 4,000 --- 76 

One (1) Champlin 242J-12 Ajax wellhead compressor --- 71 86

 Noise Emission Data – Levels at 100 ft. collected by Engineering Dynamics Incorporated. 

The project area is sparsely populated and rural in nature with a few small towns scattered along I-80 as 

well as a few temporary “man camps” in association with gas development activity in the area. Noisesensitive areas would include private residences, greater sage-grouse habitats used during breeding and 

nesting seasons, mountain plover nesting areas, and occupied raptor nests. No noise standards have been 

established by the State of Wyoming or the affected counties. 

Research into the effects of noise generated by oil and gas drilling and operations on sensitive wildlife 

species has not yet been completed. 

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CHAPTER 3—AFFECTED ENVIRONMENT—RANGE RESOURCES 

 MANAGEMENT ENVIRONMENT 

3.18 RANGE RESOURCES 

3.18.1 Introduction 

There are 47 allotments permitted for grazing use on public lands in the project area; their locations and 

boundaries are shown in Map 3.18-1. An allotment is defined as an area of land designated and managed 

for the grazing of livestock by one or more livestock operators. An allotment usually consists of public 

lands, but may include parcels of private and other federal or state-owned lands. Allotment size within the 

CD-C project area ranges from 120,536 acres (Cyclone Rim Allotment, 10103) to 118 acres for the 

Adam’s Ranch Allotment, 10501. Two of the larger allotments (Cyclone Rim and Monument Lake 

00711) make up approximately 23 percent of the total land surface area of the project area (Table 3.18-1). 

Historical cattle use in this area began in 1871 when Noah Reader brought 2,000 head that were turned 

out at the mouth of Savery Creek south of the project area. Later in 1873, George Baggs brought 2,000 

head into the valley near the vicinity of the town bearing his name (Baggs, WY). Livestock numbers 

increased rapidly until the disastrous winter of 1886–87 which ended the open-range industry in 

Wyoming when an estimated 65 percent of the state’s cattle died in a series of extreme blizzards 

accompanied by unprecedented frigid temperatures (Bennett 1999, Larson 1942). In the absence of cattle 

sheep soon became the dominant livestock in the area and were dominant from the 1890s through the 

1950s. The peak in sheep numbers in Wyoming occurred in 1909 when a total of 6,023,000 animals was 

recorded (Wyoming Agricultural Statistics Service [WASS] 1995). The total inventory of sheep in 

Carbon County has steadily decreased over the years to about 14,000 head recorded in 2006 (NASS 

2008). Cattle numbers have slowly risen through the years, with many sheep allotments converting back 

to cattle use in the 1960s through the 1980s. The peak number of cattle (all cattle) in Wyoming occurred 

in 1975 at 1,690,000 head, compared to 1,430,000 head in 2007. The most recent cattle inventory in 

Carbon County was 97,000 head, including 58,000 head of beef cows (NASS 2008). 

The affected grazing allotments in relation to the major land cover types within their boundaries are 

shown in Map 3.18-1. These allotments, which overlap portions of the CD-C project area, total 1,616,637 

acres; approximately 1,050,200 acres (65.0 percent) are located within the CD-C project area. In the 

extreme western portion of the project area, the Rock Springs Field Office manages three small grazing 

allotment inclusions, totaling about 1,289 acres. A total of five “non-allotments” are located within the 

project area with a composite total of about 19,942 acres. The largest non-allotment is located in the area 

north of the Red Desert/I-80 exit and mainly consists of numerous private ranchettes. 

The 47 grazing allotments (Table 3.18-1) are permitted for a total of approximately 191,746 animal unit 

months (AUMs), of which an estimated 123,910 would be available from within the CD-C. An AUM is 

defined in the Rawlins RMP FEIS as “a standardized unit of measurement of the amount of forage 

necessary for the sustenance of one animal unit for 1 month.” (BLM 2008a). For fee calculation, an AUM 

is defined in the Rawlins RMP FEIS as “a unit of measurement that represents the privilege of grazing 

one animal unit for 1 month” (BLM 2008a). 

Cattle operations are primarily cow/calf pairs. Cattle use occurs during all seasons, including winter use 

both south and north of I-80. Winter use depends mainly on the location of the allotment and the 

requirements of each individual livestock operation. Each allotment is usually used for one season, or 

longer if use is rotated between pastures. Most cattle operators using the project area calve on the range 

versus their homeplace. 

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CHAPTER 3—AFFECTED ENVIRONMENT—RANGE RESOURCES 

Map 3.18-1. Affected grazing allotments in the CD-C project area in relation to major land cover types 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

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CHAPTER 3—AFFECTED ENVIRONMENT—RANGE RESOURCES 

Sheep use is limited within the project area and is confined predominantly to the Willow Creek (10528), 

Mexican Graves (10516), South Barrel (10525), South LaClede (10610), North LaClede (10613), Red 

Creek (10521), Cherokee (00408), Chain Lakes (10722), Badwater (10601), South Wamsutter (10620), 

and Cyclone Rim (10103) allotments. The Chain Lakes and Cyclone Rim allotments located in the 

northern portion of the project area are primarily for winter use. 

Table 3.18-1. Estimated allotment acreage and AUMs within the CD-C project area 

Allotment 

number Allotment name 

Acres1 Percent AUMs1 

Entire 

allotment 

Within 

CD-C2 Of entire 

allotment 

Of all 

allotted 

acreage 

Entire 

allotment 

Acres 

per AUM 

(stocking 

ratio) 

Within 

CD-C2 

00408 Cherokee 66,491 3,803 5.7 0.36 9,963 7.2 531 

00415 Doty Mountain 85,936 28,903 33.6 2.75 10,111 7.9 3,660 

00442 Dad 675 620 91.7 0.06 114 6.4 97 

00443 East Muddy 6,174 620 10.0 0.06 796 7.7 80 

00514 Little Robber 507 507 100.0 0.05 250 1.9 264 

00705 Red Desert 46,560 46,557 100.0 4.43 4,075 11.5 4,060 

00706 G.L. 19,039 19,039 100.0 1.81 2,551 7.5 2,540 

00709 Jawbone 23,029 11,449 49.7 1.09 2,570 9.0 1,272 

00710 Monument Draw 15,344 15,344 100.0 1.46 1,834 8.4 1,825 

00711 Monument Lake 119,666 119,666 100.0 11.39 15,324 7.8 15,270 

00713 North Creston-West 10,662 10,646 99.9 1.01 1,938 5.6 1,898 

00714 Latham 40,161 40,159 100.0 3.82 5,116 7.8 5,148 

00715 North Tipton 26,199 26,199 100.0 2.49 2,972 8.8 2,981 

00716 North Wamsutter 59,808 59,808 100.0 5.69 6,296 9.1 6,587 

00717 Ruby Knolls 30,094 30,094 100.0 2.87 3,159 9.5 3,151 

00740 Grieve Pasture 2,176 2,136 98.2 0.20 220 9.9 216 

00801 Larson Knolls 10,215 3,843 37.6 0.37 1,287 8.0 480 

10103 Cyclone Rim 307,361 120,536 39.2 11.48 42,975 7.2 16,785 

10501 Adam's Ranch 305 118 38.8 0.01 773 0.4 323 

10503 Big Robber 17,605 17,605 100.0 1.68 1,580 11.1 1,591 

10504 Big Robber Spreaders 1,129 1,129 100.0 0.11 114 9.1 124 

10506 Continental 25,774 2,091 8.1 0.20 2,817 9.3 224 

10508 Cottonwood Hill 14,560 1,208 8.3 0.12 790 18.3 66 

10515 Mexican Flats 15,497 15,493 100.0 1.48 1,738 9.0 1,712 

10516 Mexican Graves 20,264 19,782 97.6 1.88 1,976 10.2 1,932 

10521 Red Creek 32,288 3,984 12.3 0.38 3,036 10.6 376 

10525 South Barrel 10,298 4,716 45.8 0.45 1,037 9.9 478 

10526 South Flat Top 19,010 11,342 59.7 1.08 1,771 10.6 1,066 

10527 V Spreaders 337 337 100.0 0.03 150 2.1 158 

10528 Willow Creek 76,422 1,180 1.5 0.11 5,468 14.3 83 

10530 South Muddy 1,569 182 11.6 0.02 123 12.7 14 

10531 George Dew 1,011 1,010 99.9 0.10 215 4.1 249 

10601 Badwater 22,303 20,760 93.1 1.98 2,662 8.2 2,538 

10604 Coal Bank Wash 7,640 7,640 100.0 0.73 1,053 7.3 1,049 

10607 Echo Springs 45,500 45,500 100.0 4.33 5,093 9.1 5,022 

10609 Fillmore 41,969 1,380 3.3 0.13 6,422 6.2 222 

10610 South Laclede 52,944 48,032 90.7 4.57 5,948 9.0 5,322 

10611 North Barrel 59,296 52,816 89.1 5.03 6,875 8.1 6,493 

10612 North Pine Butte 2,322 2,322 100.0 0.22 224 10.5 221 

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CHAPTER 3—AFFECTED ENVIRONMENT—RANGE RESOURCES 

Table 3.18-1. Estimated allotment acreage and AUMs within the CD-C project area, continued 

Allotment 

number Allotment name 

Acres1 Percent AUMs1 

Entire 

allotment 

Within 

CD-C2 Of entire 

allotment 

Of all 

allotted 

acreage 

Entire 

allotment 

Acres 

per AUM 

(stocking 

ratio) 

Within 

CD-C2 

10613 North Laclede 41,501 41,501 100.0 3.95 4,323 9.7 4,300 

10615 Riner 55,978 33,507 59.9 3.19 7,036 8.1 4,139 

10619 South Red Desert 10,404 10,404 100.0 0.99 1,680 6.2 1,686 

10620 South Wamsutter 31,408 31,408 100.0 2.99 2,648 11.7 2,681 

10621 Tipton 58,202 58,112 99.8 5.53 9,540 6.4 9,136 

10625 South Pine Butte 968 968 100.0 0.09 217 4.9 199 

10626 Lazy Y S Ranch 17,865 17,865 100.0 1.70 1,898 6.2 2,880 

10722 Chain Lakes 62,170 57,874 93.1 5.51 2,988 20.8 2,778 

n/a No allotment3 0 19,942 

Total 1,616,637 1,050,200 65.0 100.0 191,746 8.6 123,910

 1 Totals include all lands: private, public, and state. 2 Estimated.
 3

 Not included in totals.
 

The establishment and rapid spread of halogeton—a plant toxic to sheep, cattle, and herbivorous 

wildlife—in the project area has adversely affected livestock operations, especially sheep. Sheep losses 

due to halogeton are estimated to range between 150 to 200 head per year (Calton 2008). Cattle and 

domestic horses can also be poisoned by ingesting halogeton. Most livestock losses occur when hungry 

animals are allowed to graze in heavy infestations of halogeton. The toxic effect of ingesting halogeton is 

due to the high level of toxic sodium oxalates that occur in the plant, especially in the leaves. Halogeton is 

toxic at all growth stages but toxicity increases as the plants mature. Herbivorous wildlife have been 

observed to consume halogeton but it is believed their highly varied grass/forb/shrub diet prevents the 

animals from ingesting a lethal dose (Pfister 2012). Although undocumented, this probably applies to 

wild horses as well. 

According to grazing regulations that became effective on August 12, 1995, the State Director of the 

Wyoming Bureau of Land Management (BLM) is required to develop and implement standards for 

healthy rangelands and guidelines for grazing management (Standards for Healthy Rangelands & 

Guidelines for Livestock Grazing Management for the Public Lands Administered by the BLM in the 

State of Wyoming at: < http://www.blm.gov/wy/st/en/programs/grazing/standards_and_guidelines/­

standards.html>). Standards apply to all uses of BLM-administered public lands in Wyoming and 

represent the minimum acceptable conditions for public rangelands. The guidelines apply only to 

livestock grazing. The Wyoming standards and guidelines were submitted to the Secretary of the Interior 

in July 1997 and were approved August 12, 1997. 

The RFO continues to implement or refine Best Management Practices (BMPs) for livestock grazing, 

which promote perennial vegetation to stabilize stream banks and improve cover and litter on uplands. 

Season, duration, and distribution of livestock are the principal factors in considering management 

changes to meet desired resource objectives for both riparian and upland habitats. Specific dates or times 

must be decided on a case-by-case basis. Methods to achieve this include, but are not limited to: herding, 

pasture fencing, water developments, and vegetation treatments. Vegetation treatments are designed to 

restore plant communities with diverse species, age classes, and cover types. The ultimate goal of these 

rangeland management tools is to improve watershed cover, riparian habitat, and upland plant 

communities to ensure that long-term range quality and national and Wyoming BLM Standards for 

Healthy Rangelands are being met. 

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CHAPTER 3—AFFECTED ENVIRONMENT—RANGE RESOURCES 

These standards are the basis for assessing and monitoring rangeland conditions and trends. The 

assessments evaluate the standards and are conducted by an interdisciplinary team with participation from 

permittees and other interested parties. Assessments are only conducted on BLM-administered public 

land; however, interpretation of watershed health and water quality may reflect on all land ownerships 

within the area of analysis. The six standards are as follows: 

 Standard 1 – Watershed Health 

 Standard 2 – Riparian/Wetland Health 

 Standard 3 – Upland Vegetation Health 

 Standard 4 – Wildlife/Threatened and Endangered Species Habitat Health, Fisheries, Weeds 

 Standard 5 – Water Quality 

 Standard 6 – Air Quality
 

In the RFO, rangeland standards were assessed on an allotment basis from 1998 through 2001 (BLM 

2001a). The allotments that did not meet Standards due to livestock grazing include the Cyclone Rim 

(10103) and Jawbone (00709) allotments. Neither of these allotments met Standard # 2 

(Riparian/Wetland Health) (BLM 2001a, pp. 119-120). Other grazing allotments within the project area 

that failed to meet one or more of the six standards due to other causes such as weeds, oil and gas 

development, and other factors, include Red Desert (00705), G.L (00706), Monument Draw (00710), 

Monument Lake (00711), North Creston-West (00713), Latham (00714), North Tipton (00715), North 

Wamsutter (00716), Coal Bank Wash (10604), Echo Springs (10607), Fillmore (10609), Riner (10615), 

Ruby Knolls (00717), South Red Desert (10619), Tipton (10621), Lazy Y S Ranch (10626), and Chain 

Lakes (10722). In most instances, the specific areas that prevented the allotment from meeting a 

Standard were small compared to the total land surface area of the allotment and do not represent 

conditions over the total allotment. 

The recent extensive drought in this area of Wyoming has affected livestock operations in several ways, 

including (1) the low soil-moisture levels associated with drought which limit plant growth and reduce 

forage yields; (2) the low soil moisture which limits root growth and makes it more difficult for range 

plants to reach scarce soil moisture; (3) low germination rates which hamper successful revegetation 

efforts; (4) over a series of drought or dry years, a shift in plant species to weedy, less-productive 

species (e.g., desert alyssum, halogeton, etc.); and (5) increased livestock medical costs associated with 

respiratory diseases attributable to dry ranges and increased dust levels (see 3.6.4, Fugitive Dust 

Effects on Vegetation). 

3.18.2 Existing Allotment Disturbance 

GIS analysis of the project surface area was performed to estimate the total area of existing disturbance 

by allotment. The disturbance terminology was standardized to conform to that of Bargsten (2005) with 

the exception that all existing roads, pipeline disturbances, gas-compression facilities, storage-tank 

complexes, man-camps, construction/pipe yards, etc., were included in the HWA GIS analysis, regardless 

of whether or not they serviced an individual well or several. Bargsten (2005) defines short- and longterm disturbance as follows. 

Short-term disturbance area: the maximum areal extent of ground disturbance associated with 

construction, drilling, and completion of an individual natural gas well, including the well pad, reserve 

pit, spoils pile(s), topsoil stockpile(s), and access road authorized to serve that individual well. The 

concept is referred to elsewhere in this document as initial disturbance. 

Long-term disturbance area: the areal extent of un-reclaimed disturbance after interim reclamation 

occurs at an individual natural gas well. This is equal to the “life-of-project” disturbance area and 

represents the area, when interim reclamation is complete, that will remain in a disturbed state until the 

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CHAPTER 3—AFFECTED ENVIRONMENT—RANGE RESOURCES 

well is plugged and abandoned. This includes the production facilities, dehydrator, separator, wellhead, 

production tanks, and access road area that is surfaced and/or maintained free of vegetation. 

The existing initial and long-term disturbance acres of the 47 CD-C allotments are shown in Table 3.18-

2. The disturbance acreage in the five “non-allotments” and the three partial Rock Springs Field Office 

allotments was calculated but not used for AUM calculation results. The disturbance percentages 

represent the part of the allotment that is within the CD-C project area. 

Table 3.18-2. Historic surface disturbance by allotment, initial and long-term 

Allotment 

number Allotment name 

Total Acres 

in CD-C 

project 

area2 

Initial1 Long-term1 

Disturbance 

acres 

% of 

allotment 

Disturbance 

acres 

% of 

allotment 

00408 Cherokee 3,803 121.1 3.2 21.8 0.6 

00415 Doty Mountain 28,903 1,317.4 4.6 211.1 0.7 

00442 Dad 620 29.5 4.8 0.8 0.1 

00443 East Muddy 620 9.0 1.5 3.6 0.6 

00514 Little Robber 507 15.4 3.0 2.6 0.5 

00705 Red Desert 46,557 543.5 1.2 100.1 0.2 

00706 G.L. 19,039 723.3 3.8 18.4 0.1 

00709 Jawbone 11,449 41.3 0.4 17.4 0.2 

00710 Monument Draw 15,344 391.9 2.6 88.1 0.6 

00711 Monument Lake 119,666 5,332.9 4.5 992.6 0.8 

00713 North Creston-West 10,646 82.9 0.8 28.0 0.3 

00714 Latham 40,159 2,690.7 6.7 337.5 0.8 

00715 North Tipton 26,199 840.5 3.2 109.4 0.4 

00716 North Wamsutter 59,808 5,694.9 9.5 820.8 1.4 

00717 Ruby Knolls 30,094 341.5 1.1 65.3 0.2 

00740 Grieve Pasture 2,136 120.1 5.6 18.4 0.9 

00801 Larson Knolls 3,843 15.7 0.4 6.0 0.2 

10103 Cyclone Rim 120,536 2,309.7 1.9 533.5 0.4 

10501 Adam's Ranch 118 7.0 5.9 0.5 0.4 

10503 Big Robber 17,605 639.7 3.6 130.4 0.7 

10504 Big Robber Spreaders 1,129 48.4 4.3 5.9 0.5 

10506 Continental 2,091 1.6 0.1 0.0 0.0 

10508 Cottonwood Hill 1,208 65.2 5.4 16.3 1.4 

10515 Mexican Flats 15,493 649.5 4.2 152.8 1.0 

10516 Mexican Graves 19,782 613.0 3.1 126.4 0.6 

10521 Red Creek 3,984 81.0 2.0 18.9 0.5 

10525 South Barrel 4,716 128.2 2.7 32.5 0.7 

10526 South Flat Top 11,342 306.1 2.7 77.2 0.7 

10527 V Spreaders 337 27.5 8.1 4.3 1.3 

10528 Willow Creek 1,180 0.0 0.0 0.0 0.0 

10530 South Muddy 182 0.0 0.0 0.0 0.0 

10531 George Dew 1,010 6.6 0.7 0.5 0.1 

10601 Badwater 20,760 521.6 2.5 87.1 0.4 

10604 Coal Bank Wash 7,640 483.4 6.3 79.0 1.0 

10607 Echo Springs 45,500 5,012.9 11.0 835.1 1.8 

10609 Fillmore 1,380 0.1 0.0 0.0 0.0 

10610 South Laclede 48,032 4,185.4 8.7 646.5 1.3 

10611 North Barrel 52,816 2,303.5 4.4 384.8 0.7 

10612 North Pine Butte 2,322 152.8 6.6 31.7 1.4 

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Table 3.18-2. Historic surface disturbance by allotment, initial and long-term, continued 

Allotment 

number Allotment name 

Total Acres 

in CD-C 

project 

area2 

Initial1 Long-term1 

Disturbance 

acres 

% of 

allotment 

Disturbance 

acres 

% of 

allotment 

10613 North Laclede 41,501 4,422.8 10.7 556.9 1.3 

10615 Riner 33,507 1,271.0 3.8 205.8 0.6 

10619 South Red Desert 10,404 204.1 2.0 47.2 0.5 

10620 South Wamsutter 31,408 2,674.1 8.5 461.3 1.5 

10621 Tipton 58,112 1,577.5 2.7 241.3 0.4 

10625 South Pine Butte 968 43.2 4.5 9.9 1.0 

10626 Lazy Y S Ranch 17,865 1,130.1 6.3 175.8 1.0 

10722 Chain Lakes 57,874 292.6 0.5 85.1 0.1 

n/a No allotment3

 19,942 1,747.7 n/a 683.5 n/a 

Totals 1,070,142 49,218.0 n/a 8,472.0 n/a 

1 Totals include all lands, private, public, and state. 2

 Estimated. 

3 Not included in totals. 

3.19 OIL AND GAS AND OTHER MINERALS 

Mineral resources within the CD-C project area include deposits of base and precious metals, bentonite, 

gypsum, limestone, uranium, zeolite, gravel, and klinker, as well as oil, gas, coal, and coalbed methane 

(CBM) (BLM 2003b). Federal mineral management organizes minerals into three categories: locatable, 

leasable, and mineral materials. 

Locatable minerals are all minerals subject to exploration, development, and production under the 

provisions of the Mining Law of 1872. Locatable minerals include both metallic minerals (gold, silver, 

lead, etc.) and nonmetallic minerals (such as fluorspar, asbestos, mica, and gemstones.). Mining claims 

can be located for such minerals pursuant to 43 CFR Part 3830. Originally, all minerals except coal were 

obtained under the Mining Law of 1872; however, Congress has removed certain minerals from the 

operation of the Mining Law. Since 1920, the federal government has leased energy fuels and certain 

other minerals. Since 1947, the federal government has sold common varieties of sand, gravel, stone, 

pumice, pumicite, cinders, and ordinary clay. Leasables and salables are described below. 

Leasable minerals are subdivided into two classes, fluid and solid. 

	 Fluid minerals include oil and gas; geothermal resources and associated by-products; and oil shale, 

native asphalt, oil impregnated sands, and any other material in which oil is recoverable only by 

special treatment after the deposit is mined or quarried. 

	 Solid leasable minerals are those leased under the mineral leasing acts and those hardrock minerals 

leased under Reorganization Plan No. 3 of 1946 (acquired lands), such as coal and phosphates. 

Leasable minerals are managed under the Mineral Leasing Act of 1920, as amended and supplemented. 

Mineral materials, also termed “salable” minerals, include common varieties of sand, stone, gravel, 

pumice, pumicite, cinders and clay, which are generally put to use in building and construction. BLM 

disposes of mineral materials via contract sales where the material is sold by the ton or cubic yard at fair 

market value, or provides them to governmental entities or nonprofit organizations under free use permit 

pursuant to the regulations at 43 CFR Part 3600. 

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CHAPTER 3—AFFECTED ENVIRONMENT—OIL AND GAS AND OTHER MINERALS
 

3.19.1 Locatable Minerals 

The most important locatable mineral found in the CD-C project area is uranium. The Wyoming State 

Geological Survey's Uranium Map of Wyoming (WSGS 2010) shows four uranium mining districts in or 

near the CD-C project area. The Great Divide Basin Mining District is the largest and the only one within 

the CD-C project area, overlapping the upper third of the project area. Uranium-bearing prospects there 

occur in arkoses of the Battle Spring Formation (Pipiringos 1961) that is exposed just west of the project 

boundary; in coals of the main body of the Wasatch Formation, north of Wamsutter (Masursky 1962); and 

around the towns of Creston and Latham (Harris et al. 1985, Harris and King 1993). The only notable site 

of mining claims for locatable minerals in the CD-C project area is located within the Great Divide Basin 

sedimentary uranium deposits. Over 80 mining claims have been filed in sections 3, 10, 12-15, 24, and 

35, T23 N:R94W in the north central portion of the project area, along the Crooks Gap Road (available at: 

http://www.blm.gov/landandresourcesreports/rptapp/criteria_select.cfm?rptId=19&APPCD=2&). 

The Poison Basin (Baggs) Mining District lies just west of the town of Baggs and about five miles outside 

the CD-C project’s southern boundary. The Ketchum Buttes District lies about 15 miles east of the project 

area in T15N:R89W. A fourth district, the Crooks Gap-Green Mountain Minding District, is located about 

20 miles north of the project area boundary. 

No uranium development activity has taken place within the CD-C project area, but historic activity has 

occurred in all four of the described districts and the Great Divide Basin and Crooks Gap-Green Mountain 

districts contain several proposed new developments. One, the Lost Creek Uranium In-Situ Recovery 

Project, is located several miles north of the CD-C project’s northern boundary in sections 16–20, T25 

N:R92W and sections 13, 24, and 25, T25N:R93W. The proposed mine is expected to be in operation for 

about 12 years. 

3.19.2 Leasable Minerals 

Coal and CBM occur in Tertiary and Cretaceous-age geologic formations, and oil and gas occur in 

geologic formations of Tertiary, Cretaceous, Jurassic, Triassic, and Pennsylvanian age underlying the 

project area. Oil shale resources occur within the Green River Formation in the Washakie Basin; 

however, the most geologically prospective oil shale resources of the Washakie Basin occur to the 

southwest of the CD-C project area (2012 Oil Shale and Tar Sands Draft Programmatic Environmental 

Impact Statement, posted at http://ostseis.anl.gov/documents/peis2012/) and so this resource will not be 

discussed further in this document. Other leasable minerals that occur within the CD-C project area are 

phosphate and sodium. The 2003 Mineral Occurrence and Development Potential Report, prepared for 

the RFO RMP (BLM 2003), indicates that the potential for development of phosphate is low. The report 

also concluded that the nature of the sodium deposits within the RFO (including the CD-C project area), 

in conjunction with the available domestic production capacity, suggests that there is little potential for 

commercial exploitation of the RFO’s phosphate deposits. Because the potential for development is low, 

phosphate and sodium will not be discussed further in this document. 

3.19.2.1 Coal and Coalbed Methane 

Fort Union Formation 

The Fort Union Formation of south and southwest Wyoming constitutes an enormous, largely untapped 

reserve of coal. Coals occur throughout the formation, but are thickest and most continuous in its lower 

part (the lower coal-bearing unit) (Smith et al. 1972, Sanders 1974 and 1975, Beaumont 1979, Edson 

1979, Hettinger and Brown 1979, Honey and Roberts 1989, Honey and Hettinger 1989, Honey 1990, 

Jones 1991, Hettinger et al. 1991). 

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Within and adjacent to the project area, coal seams of the Fort Union Formation comprise the CrestonCherokee and Green River coals. These coals are best developed along the east side of WY 789 in 

T19N:R92W and include about 20,364 leasable acres. 

Studies of the Fort Union Formation coals in the project area and adjacent areas have been conducted by 

Sanders (1974, 1975), Edson (1979), Honey and Hettinger (1989), Honey and Roberts (1989), and Honey 

(1990). As many as ten coal seams have been mapped in the subsurface with individual seams averaging 

10 to 20 feet thick, but thickening to as much as 40 feet. Net coal thickness increases in the subsurface 

southward toward the Baggs area where it may reach a maximum of about 75 feet. Thicker Fort Union 

coals have been interpreted to have accumulated in flood plains above and on the flanks of major 

Paleocene-age, south/north-oriented river systems. Thinner coal seams accumulated away from these 

main trunk streams. 

The Fort Union Formation is a primary CBM target in the southeastern Greater Green River Basin, but 

the formation crops out at the surface only in the easternmost part of the project area, so few if any of the 

coalbeds that dip westward are buried deep enough to be candidates for development. Deeper buried 

coalbeds west and south of the area have ash-free gas contents generally less than 100 standard cubic feet 

per ton (scf/ton), but ranging from 9 to 561 scf/ton. Scott et al. (1994) estimated coal gas reserves in the 

western and southwestern parts of Carbon County underlying the project area to be less than 2 billion 

cubic feet (Bcf) per square mile (mi2

) near the eastern margins of its subcrop, to 6–8 Bcf/mi2 in deeper 

buried areas north and west of Baggs. These values may be enhanced by migration of gases into the area 

from deeper parts of the basin. Based on vitrinite reflectance percentages from wells in the Sand Wash 

Basin, Fort Union coals rank as sub-bituminous high volatile C bituminous and high volatile B 

bituminous. 

Lance Formation 

Coals occur discontinuously in outcrops in the Lance Formation from I-80 south for about 25 miles. 

Averaging about five feet in thickness, but ranging from a few inches to 22 feet thick, these coals are 

thicker, more abundant, and laterally extensive in the lower part of the formation. The coals have limited 

lateral extent and usually cannot be traced more than a few hundred to several thousand feet. Lance 

Formation coalbeds are minor CBM targets (Scott et al. 1994). 

Mesaverde Group 

Coal occurs in outcrops in the Mesaverde Group in several places along the western edge of the Sierra 

Madre, and exists in the subsurface within the project area. These coals are best developed high in the 

Mesaverde Group near its contact with the overlying Lewis Shale in exposures east of the project area, 

along the eastern edge of the project area (Atlantic Rim and Green River Coal Fields) and in T15­

16N:R90-91W (an unnamed coal field). These fields include about 230,400 leasable acres. Coals are also 

developed sporadically lower in the Mesaverde Group (Allen Ridge Sandstone) but these coals are thin 

and discontinuous. Based on vitrinite reflectance percentages from wells in the Sand Wash Basin, the 

Mesaverde coals underlying the project area rank as high volatile C bituminous, high volatile B 

bituminous and high volatile A bituminous. 

Coals in the Ericson Sandstone (a/k/a Pine Ridge Sandstone or Williams Fork Formation) include the 

thickest and most extensive coals of the Upper Cretaceous in the Greater Green River Basin and are the 

basin’s prime CBM targets. The maximum net coal thickness of about 220 feet, contained in 40 

individual coalbeds, occurs near Craig, Colorado. The coalbeds thin in a westerly and northerly direction, 

so that in the southeastern part of Carbon County, underlying the project area, net coal thicknesses range 

from 40 to 90 feet. These coals are interpreted to have accumulated in coastal plain environments and 

fluvial-dominated, wave-modified deltas, along a southwest/northeast-oriented strand (beach) line that 

faced southeastward into the Cretaceous epicontinental seaway. 

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Gas content values for coals developed in the Ericson Sandstone (a/k/a Pine Ridge Sandstone or Williams 

Fork Formation) range from less than 1 to more than 540 scf/ton, but are generally less than 200 scf/ton. 

Based on gas content values, Scott et al. (1994) estimated coal gas reserves in the western and 

southwestern parts of Carbon County underlying the project area to be less than or equal to 10 Bcf/mi2 

near the eastern margins of its subcrop and 8 to 40 Bcf/mi2

 in the extreme southwestern corner of the 

county. 

Coals in the Rock Springs Formation (a/k/a Allen Ridge Sandstone or Iles Formation) are thinner and not 

as well-developed as those in the Pine Ridge and the formation is considered a minor coal-bearing unit 

and CBM target. A maximum net coal thickness of 32 feet occurs in the easternmost part of the Great 

Divide Basin, but in most other places it is typically less than 15 feet. These coals are interpreted to have 

accumulated in a variety of swampy environments above shoreline sandstones and in floodplains adjacent 

to delta river channels. 

Based on samples from wells primarily in the Rock Springs Uplift, gas content values in the Rock Springs 

Formation (a/k/a Allen Ridge Sandstone or Iles Formation) range from zero to more than 650 scf/ton. No 

estimates of total coal gas reserves are available for this unit. 

3.19.2.2 Oil and Gas 

The region within which the CD-C project is located has produced substantial quantities of oil and natural 

gas, principally from Cretaceous rocks, but with additional notable resources derived from the Tertiary 

Wasatch and Fort Union Formations, and from the Pennsylvanian Tensleep Sandstone. 

Developed oil and gas fields within the area are listed in Table 3.19-1. Most of these fields produce 

principally from stratigraphic traps in sandstones of the Tertiary and upper Cretaceous formations 

(DeBruin, 1996); a few produce from structural traps. 

The Oil and Gas Fields Symposium Committee (1957, 1979, 1992), Gregory and DeBruin (1991), 

DeBruin and Boyd (1991), and DeBruin (1996) report oil and gas from wells penetrating the Cretaceous 

Niobrara, Lance, Shannon Sandstone, and Mesaverde formations in the region surrounding the towns of 

Dixon and Savery (east of the southern part of this study area), as well as some shows there from the 

Tensleep Formation. The Baggs South Oil and Gas Field and the West Side Canal Oil and Gas Field 

(Cronoble 1969; DeBruin 1993; Kaiser et al. 1994) produce oil and gas (largely gas) from combined 

stratigraphic and faulted structural traps in the lower Eocene Wasatch, the Paleocene Fort Union, and the 

Upper Cretaceous Lance, Fox Hills, Almond, and Lewis Shale (sandstone facies) in T12–13 N:R90–93 

W, in the southern part of the adjacent Atlantic Rim CBM area. 

Regionally, Colson (1969) reported Tertiary oil and gas production from all Tertiary stratigraphic units 

from the Tipton Tongue of the Green River Formation (within the report’s study area), down to the level 

of the Cretaceous/Tertiary (Lance/Fort Union) unconformity. In the South Baggs Field in T12 N:R92 W 

(south of this study area), oil and gas are concentrated at the crest of a structural high (probably a faulted 

anticline) in the Fort Union Formation. Farther east, production in the West Side Canal Field (T12N:R 

91–92W) is from the lower sandy interval of the Paleocene Fort Union Formation, also in a structural trap 

on a faulted anticline. 

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CHAPTER 3—AFFECTED ENVIRONMENT—OIL AND GAS AND OTHER MINERALS
 

Table 3.19-1. Oil and gas fields in the CD-C project area and cumulative production as of 2007 

Field General 

Location Discovered Producing Horizons (alphabetical) 

Production/ 

Oil (BBLS) 

Production 

Gas (MCF) 

Baldy Butte 17N–92W 1982 Almond, Lewis, 

Mesaverde 280,142 25,717,419 

Barrel Springs 16N–93W 1965 Almond, Lance, Lewis, 

Mesaverde 1,135,636 115,954,827 

Bastard Butte 25N–97W 1978 Lewis 7,200 9,806 

Battle Springs 23N–94W 1979 Almond, Ericson, 

Lewis, Mesaverde 17,732 1,754,063 

Blue Gap 15N–92W 1974 Almond, Lance, Lewis, 

Mesaverde 393,537 44,171,587 

Bush Lake 24N–96W 1978 Almond, Lance, Lewis 9,042 5,081,050 

Coal Gulch 17N–93W 1977 Almond, Lewis, 

Mesaverde 1,461,251 110,000,237 

Continental Divide 22N-93W 1964 Dakota, Ericson, Lewis, 

Mesaverde 54,117 875,731 

Cow Creek 16N–92W 1960 

Cow Creek, Dakota, 

Deep Creek, Frontier, 

Lewis, Mesaverde, 

Maropos, Muddy, 

Lakota, Nugget, Trout 

Creek 

1,850 22,352,883 

Creston 19N–92W 1960 

Almond, Blair, Ericson, 

Frontier, Lewis, 

Mesaverde 

481,245 36,871,009 

Creston Southeast 19N–90W 1977 Almond 151 105,857 

Delaney Rim Unit 18N–97-98W 1976 Almond, Lewis, 

Mesaverde 1,339,974 10,513,455 

Echo Springs 19N–93W 1976 Almond, Ericson, 

Lewis, Mesaverde 9,942,729 572,186,906 

Emigrant Trail 17N–95W 1981 Almond, Lance, Lewis, 

Mesaverde 68,305 2,009,639 

Fillmore 20N–92W 1977 Almond, Ericson, 

Lewis, Mesaverde 335,805 8,633,145 

Five Mile Gulch 21N–93W 1977 Almond Ericson, Lewis, 

Mesaverde 213,256 12,758,321 

Frewen 19N–95W 1990 

Almond Frontier, 

Lakota, Lewis, 

Mesaverde 

789,764 22,250,444 

Gale 23N–96W 1980 Ericson, Lewis 3,295 325,885 

Great Divide 22–23N 

95–96W 1978 Lance Lewis 346,116 10,674,736 

Hay Reservoir 24N–97W 1977 

Almond, Big Coal, 

Lance, Lewis, 

Mesaverde 

2,615,544 165,002,506 

Lost Creek Basin 23N–95W 1981 Ericson, Lewis, 

Mesaverde 28,413 635,377 

Lost Creek 23N–97W 1972 Lewis 375 29,301 

Monument Lake 21N–92W 1977 Almond, Ericson, 

Mesaverde 20,057 1,634,814 

Nickey 24N–96W 1980 Almond, Lewis 1,511 1,785,984 

Red 16N–94W 1979 Mesaverde 2,240 106,418 

Red Desert 18N–97-98W 1971 Almond, Lewis, 

Mesaverde 240,542 23,318,701 

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CHAPTER 3—AFFECTED ENVIRONMENT—OIL AND GAS AND OTHER MINERALS 

Table 3.19-1. Oil and gas fields in the CD-C project area and cumulative production as of 2007, 

continued 

Field General 

Location Discovered Producing Horizons (alphabetical) 

Production/ 

Oil (BBLS) 

Production 

Gas (MCF) 

Robbers Gulch 14N–91W 1962 Almond, Lance, Lewis, 

Mesaverde 238,479 35,649,093 

Salazar 16N–95W 1975 Lewis, Mesaverde 4,735 535,536 

Sentinel Ridge 23N–94W 1977 Almond Ericson, Lewis, 

Mesaverde 4,761 1,045,093 

Shell Creek 19N–96W 1977 Almond, Mesaverde 11,935 521,586 

Siberia Ridge 21N–94W 1976 Almond, Ericson, 

Lewis, Mesaverde 2,427,328 147,569,111 

Standard Draw 18N–93W 1978 

Almond, Ericson, 

Lakota, Lewis, 

Mesaverde, Steele 

8,467,259 505,804,384 

Stock Pond 22N–95W 1978 Almond, Ericson, 

Mesaverde 10,502 1,318,232 

Strike 22N–95W 1994 Almond, Ericson, 

Lewis, Mesaverde 138,919 2,000,549 

Table Rock 18–19N 

97–98W 1946 

Almond, Blair, Carney 

Coal, Dakota, Ericson, 

Fort Union, Fox Hills, 

Frontier, Lewis. 

Madison, Mesaverde, 

Morgan, Nugget, 

Wasatch, Weber 

6,378,299 716,430,993 

Table Rock SW 18N–98W 1955 Almond, Lewis 37,589 1,628,192 

Tierney 19N–94W 1973 Almond, Frontier, 

Lewis, Mesaverde 1,394,555 42,717,016 

Wamsutter 20–21N 

94–95W 1958 

Almond, Ericson, 

Lance, Lewis, 

Mesaverde, Rock 

Springs 

3,745,535 36,672,037 

Wells Bluff 18N-96W 1977 Almond, Ericson, 

Mesaverde 24,480 555,970 

Wild Rose 17-18N-94W 1975 

Almond, Ericson, Fort 

Union, Lance, Lewis, 

Mesaverde 

6,692,296 399,132,288 

Windmill Draw 15N-94W 1979 Almond, Ericson, 

Mesaverde 1,987 870,431 

3.19.3 Mineral Materials 

Mineral materials, also termed “salable” minerals, include common varieties of sand, stone, gravel, 

pumice, pumicite, cinders and clay, which are generally put to use in building and construction. Salable 

minerals disposition is addressed under the Materials Act of July 31, 1947, as amended by the Acts of 

July 23, 1955 and September 28, 1962 (BLM 2003b). The BLM disposes of mineral materials via 

contract sales where the material is sold by the ton or cubic yard at fair market value, or provides them to 

governmental entities or nonprofit organizations under free-use permit pursuant to 43 CFR Part 3600 

regulations. Potential purchasers or permittees may conduct pre-application sampling and testing of a 

mineral material deposit per 43 CFR 3601.30 (BLM 2012d). 

The most significant salable mineral within the RFO—and within the CD-C project area—is aggregates, 

or sand and gravel, occurring in the project area typically as terrace and alluvial sand and gravel deposits 

and as windblown (dune) deposits. Mapped occurrences of sand and gravel deposits are found at the 

following general locations in and near the project area (2003b): 

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CHAPTER 3—AFFECTED ENVIRONMENT—OIL AND GAS AND OTHER MINERALS 

 T25N:R95-96W North of Lost Creek Basin (terrace) 

 T22N:R95-96W Northeast flank of the Red Desert Basin (terrace) 

 T20-21N:R92W Creston Junction area (terrace) 

 T24N:R96W East of Hay Reservoir (alluvial) 

 T24N:R95W Mouth of Eagle’s Nest Draw (alluvial) 

 T19N:R93W Echo Springs, southeast of Wamsutter (alluvial) 

 T12-17N:R91-92W Muddy Creek area (alluvial) 

 T21-23N:R95-96W Red Desert Basin (windblown sand) 

 T16-17N:R93-94W Barrel Springs Draw (windblown sand) 

Also present within the project area are pumice and scoria, near Creston Junction, and baked and fused 

shale (known locally as “scoria” or “klinker” but not technically a true volcanic scoria), with several large 

deposits in the area stretching from Creston Junction to Baggs. Both are important local sources of 

aggregate. Some of these deposits have been developed as gravel pits. Sources on BLM-administered land 

are located near Wamsutter (T19N:R95W), Creston Junction (T20N:R91W), and along the Little Snake 

River (T12-13N:R90-91W) (BLM 2003b). Several sites on private lands also provide mineral materials. 

Map 3.19-1 shows the locations of permitted sand and gravel and scoria mines by section within and 

adjacent to the CD-C project area (WDEQ – Land Quality Division 2012). 

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CHAPTER 3—AFFECTED ENVIRONMENT— OIL AND GAS AND OTHER MINERALS
 

Map 3.19-1. Permitted sand, gravel, and scoria/klinker mines within and near the CD-C project area 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

3-216 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
 

 

CHAPTER 3—AFFECTED ENVIRONMENT—HEALTH AND SAFETY 

3.20 HEALTH AND SAFETY 

Existing health and safety concerns in and adjacent to the project area include occupational hazards 

associated with natural gas exploration and operations, the operation of vehicles on improved and 

unimproved roads, natural gas pipeline operations, winter driving and working conditions, hunting-related 

firearms accidents, collisions with livestock and big game, and low-probability natural hazards associated 

with events such as landslides, flash-floods, range fires, or winter blizzards. 

3.20.1 Worker Safety 

Health and safety concerns within the existing project area are primarily the occupational hazards 

associated with oil and gas development and production activities. Operators and service companies 

working within the field are governed by the State of Wyoming Department of Employment Workers 

Occupational Health and Safety (WOSHA) program. WOSHA has adopted the federal Occupational 

Safety and Health Administration (OSHA) general construction program rules and regulations and has 

special rules for oil and gas well drilling, well servicing, and special servicing operations. 

The project workforce can be divided into two groups: those associated with drilling and completion 

activities and those involved in production operations. Drilling services employment categories had a 

non-fatal accident rate of 6.8 per 100 employees in 2004 compared to the operations support category 

non-fatal accident rate of 2.7 in the same year (U.S. Department of Labor, OSHA 2007). Due to the high 

level of accidents (greater than three lost work-day injuries and illness, or LWDII) experienced in these 

occupations, oil and gas well drilling is one of the OSHA target industries in a cooperative effort between 

OSHA and industry partners to reduce accident and fatality rates. By 2009, these accident levels had 

dropped to 1.9 and 2.2, respectively (OSHA Bureau of Labor Statistics 2009). By comparison, all private 

industry workplaces reported a LWDII injury rate of 4.0 per 100 employees in 2009 (Bureau of Labor 

Statistics 2009). 

Natural gas gathering, compression, stabilization, and transmission operations currently take place in the 

project area. Most natural gas transmission and gathering pipeline operations are regulated by the U.S. 

Department of Transportation (USDOT) Office of Pipeline Safety (OPS). In 2006 there were 133 onshore 

natural gas transmission and gathering line accidents reported nationwide, resulting in three fatalities and 

four injuries; in 2010 there were 92 such accidents including eight fatalities in the transmission line 

system (USDOT OPS 2011). The OPS regulations require stringent system maintenance programs, 

emergency response planning, risk management planning, and individual personnel operations and 

maintenance training for each natural gas pipeline system. 

3.20.2 Public Health and Safety 

The project area is attractive to local residents as a recreation area for such pursuits as bird and big game 

hunting, rock-hounding, and seeking solitude. The area is also home for scattered rural families and their 

ranching operations. 

The roads within the project area see a wide variety of use. BLM and county roads have historically been 

built to the appropriate standards for the anticipated use, as have the private roads in the area. Single-lane 

dirt roads provide access to individual well sites and are used primarily by site workers but may be used 

by bird and big game hunters. In an effort to protect their employees, as well as the public, the Operators 

have safe driving policies in place. The project area is intersected by I-80. This very high-volume 

interstate highway provides access to the project area for contractors, drilling crews, production 

personnel, and the general public. This topic is more fully discussed in Section 3.16 Transportation. 

The OPS regulates some aspects of gas-gathering and transmission pipelines operated in the field and 

beyond. USDOT regulations also address the safe transportation of hazardous materials (i.e. condensate, 

crude oil, methanol, drilling mud chemicals) on the national roads and highways. The gas produced in the 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 3-217 
CHAPTER 3—AFFECTED ENVIRONMENT—HEALTH AND SAFETY 

project area is generally “sweet,” meaning it does not contain hydrogen sulfide (H2S), and therefore it 

does not pose a H2S hazard to the general public or to site workers. 

Fire-prevention measures for pipeline and site construction are in place during the summer construction 

season. These include using equipment with spark arrestors, welding in cleared areas only, and the ready 

availability of fire extinguishers or water trucks in the event fire occurs. The BLM requires extra 

precautions in the event of drought or high fire danger. 

Local and state emergency responders are annually provided information regarding the location and 

nature of hazardous materials that are held in quantities in excess of their regulatory threshold planning 

quantity (TPQ) or 10,000 pounds, as appropriate. All Operators and their contractors are required to 

supply this information under the Community Right-to Know Laws (40 CFR 355 and 370, as amended). 

Each Operator has an Emergency Action Response Plan as well as access to the trained personnel and 

equipment needed to respond to releases of hazardous materials or other hazardous conditions in the 

project area. 

3.20.3 Other Risks and Hazards 

Any firearm-related accidents would occur primarily during hunting season. No data were available to 

estimate or discuss the likelihood of risk for gas-field workers to be injured by hunters. Risk of humancaused fire in the project area is low. 

3.21 WASTE AND HAZARDOUS MATERIALS MANAGEMENT 

Numerous companies operate within the project area; all Operators and their contractors are responsible 

for compliance with all local, state, and federal regulations applicable to their operations for 

environmental protection. Different companies have different compliance philosophies, ranging from 

minimal compliance to compliance programs that exceed regulatory requirements. 

3.21.1 Waste Management 

The management of non-exempt hazardous and non-hazardous (solid) wastes is regulated under the 

Resource Conservation and Recovery Act (RCRA) (40 CFR Part 260-268) while the management of 

releases of hazardous materials into the environment is regulated under the Comprehensive 

Environmental Response, Compensation and Liabilities Act (CERCLA) (40 CFR Part 300-374). Oil and 

gas exploration, production, gas-gathering, processing wastes, and releases of hazardous materials into the 

environment are generally considered to be RCRA-exempt and are regulated by the WOGCC or WDEQ 

and the BLM. All wastes are to be treated or disposed of in an approved manner consistent with existing 

laws and regulations (Gold Book, BLM 2007b). Non-exempt wastes will not be mixed with exempt 

wastes. BLM Wyoming has established policy regarding the management of exploration and production 

wastes (WY 2012-007, November 15, 2011), and the applicable standards from the IM will be considered 

and evaluated at the time APDs or Sundry Notices are reviewed by the BLM. 

A number of permitted solid or hazardous waste sites in the project area are identified in the WDEQ Solid 

and Hazardous Waste Division database. These range from the historic Wamsutter landfill to active 

disposal facilities for specific gas-field operational areas. 

Non-hazardous solid waste typically includes oil and gas exploration, production, and gas-gathering, as 

well as processing wastes and releases of hazardous materials into the environment, and is considered 

RCRA-exempt. These materials are variously regulated by WDEQ, WOGCC, and the BLM. Buried 

materials may also be present in association with historic homestead locations. Non-hazardous solid 

wastes generated from operations are hauled to municipal landfills in Wamsutter, Rock Springs, and 

Rawlins. 

3-218 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
CHAPTER 3—AFFECTED ENVIRONMENT—WASTE AND HAZARDOUS MATERIALS
 

Hazardous wastes are generated in association with some gas-processing operations in the CD-C project 

area. These wastes and disposal sites are permitted and managed in compliance with the WDEQ 

hazardous waste program regulations. 

Non-hazardous trash and debris are collected in dumpsters or trash cages at the individual well sites, 

compressor stations, construction sites, and man camps. Trash is also collected in individual containers or 

bags for off-site disposal. These waste materials are disposed of in accordance with state standards as 

imposed by the county sanitarian. 

Drilling Mud – Portions of the project area have been producing natural gas and oil since at least 1958. 

Regulations and industry standards for the management of wastes have changed substantially since that 

time. Until the 1980s waste materials generated during drilling, production, and processing operations 

would typically have been buried near the point of generation within the field area. Reserve pit contents 

may have been buried at older producing or plugged-and-abandoned well sites. The disposal of these 

materials is now regulated and approved by the WOGCC and the BLM. More recently some of the 

Operators have recycled drilling mud between wells for re-use. This practice reduces the volume of 

material to be disposed of. Historically, the BLM required drilling pits to be fenced upon rig release and 

backfilled within six months of well completion. If a liner has been used in the reserve pit, any liner 

material must be removed to below ground-level before being covered. Completion fluids are also 

recycled to the extent possible to minimize waste disposal but are generally produced to an open pit onsite 

for disposal. Reserve-pit and well-completion wastes are generally classified by the EPA as “exempt nonhazardous” and are not regulated by the RCRA (40 CFR 261.4). 

In the event flaring or venting of natural gas is required to facilitate safe operations, Operators must 

comply with the notification provisions of BLM Notice to Lessee (NTL)-4A, which allows the flaring of 

gas in emergencies for up to 30 days or 50 MMcf. Longer duration or higher-volume flaring events would 

require subsequent BLM approval. Operators must also follow WDEQ Air Quality and WOGCC rules. 

Produced water within the project area is currently managed through the use of private and 

commercially permitted evaporation ponds and injection/disposal wells. These facilities have been 

permitted by the WOGCC, WDEQ, and the BLM as applicable. The specific permitting mechanism 

depends on facility ownership, source of produced water, and location. Historically, water may have been 

allowed to evaporate onsite using individual produced-water disposal pits; this practice is no longer 

common. 

Sanitary wastes are disposed of in permitted septic systems for permanent and long-term temporary 

facilities such as offices and man camps. Portable toilets are provided for long-term construction, drilling, 

and completion operations; these wastes are hauled to municipal sewage-treatment plants for disposal. 

3.21.2 Hazardous Materials Management 

The affected environment for releases of wastes or hazardous materials includes air, water, soil, and 

biological resources that may be impacted by the release in the course of transportation, use, or storage of 

the material in construction or field operations. Areas that are particularly vulnerable to the release of 

such materials include wetlands, water bodies, areas of shallow groundwater and areas where wildlife and 

humans could be directly impacted. 

Hazardous materials are used in drilling, field development, construction, completion, and production 

operations. BLM requires that NEPA documents list and describe any materials categorized as Hazardous 

or Extremely Hazardous that would be produced, used, stored, transported, or disposed of as a result of a 

proposed project (IM 1994-081, WY Information Bulletin 1997-011 and IM WY-94-059). This 

compilation for the CD-C project can be found in Appendix K, Hazardous Materials Management 

Summary. Operators are encouraged to substitute less-toxic yet equally effective products when 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 3-219 
 

CHAPTER 3—AFFECTED ENVIRONMENT—WASTE AND HAZARDOUS MATERIALS
 

available (BLM 2007b) in all phases of operations. Substitutions are not always available; therefore, it is 

acknowledged that hazardous materials may be used in the project area. 

Numerous companies operate within the project area; each has a responsibility to comply with the state 

and federal regulations applicable to its operations. Different companies have different compliance 

philosophies, ranging from minimal compliance to compliance programs that exceed regulatory 

requirements. Each company is required to provide the RFO with an Emergency Response Plan that 

covers its operations within the RFO. These documents serve two purposes: to ensure that company 

personnel are aware of the need to notify the RFO in the event of an emergency involving hazardous 

substances, produced water, and/or hydrocarbons; and to verify that contingency planning for such an 

emergency is in place. Company documents regarding spill-response planning, Community Right-toKnow reports, Spill Prevention, Control, and Countermeasure (SPCC) plans, and documents containing 

other relevant information, are maintained by the individual Operators. 

3.21.3 Hazardous Materials Releases and Spill Response 

The Operators have trained personnel and/or contractors as well as the equipment needed to respond to 

releases of hazardous materials in the project area. Wells in the project area are completed in a number of 

different hydrocarbon reservoirs and produce a variety of fluids including condensate and oil in addition 

to natural gas and water. There is potential for these produced fluids as well as materials brought in for 

operations such as fuel, lube oils, mud products, and completion fluids to be released into the 

environment. Releases of materials are reported to state and federal regulators as required. BLM NTL-3A 

is the appropriate mechanism for reporting spills (of hydrocarbons, produced water, or other hazardous 

materials), accidents, blowouts, or other undesirable events that occur from federal minerals or on BLMmanaged surface; otherwise, spills of hydrocarbon, produced water, and/or hazardous materials are 

reported to WDEQ (Section 4 of Chapter 4 of WDEQ Wyoming Water Quality Rules and Regulations) 

and WOGCC (Section 3 of Chapter 4 of WOGCC Rules). Remediation of contaminated soils or off-site 

disposal of contaminated material is approved by BLM prior to the management action. Operators must 

comply with the applicable provisions of the EPA’s SPCC regulations found at 40 CFR 112. These 

regulations require secondary containment for mobile and non-mobile equipment as well as some 

transportation-related activities that contain oil in volumes greater than 1,320 gallons that could impact 

navigable waters of the U.S. in the event the material is released. This rule applies to compressor stations, 

drilling and production operations, as well as other activities within the project area. Most Operators in 

the project area have prepared contingency plans that will be activated should there be an emergency or 

hazardous materials release. 

3-220 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
4. ENVIRONMENTAL CONSEQUENCES 

4.0.1 Introduction 

The purpose of this chapter is to assess and disclose the environmental effects of the Continental DivideCreston Natural Gas Development Project. The analysis is guided by the regulations set forth by the 

Council on Environmental Quality (CEQ), which call for analysis of the direct, indirect, and cumulative 

effects of the Proposed Action and the alternatives (40 CFR 1500-1508). Direct effects are those caused 

by an action and occurring at the same time and place as the action—for example, the surface disturbance 

that occurs when a well pad is constructed. Indirect effects are caused by the action but “are later in time 

or farther removed in distance”—for example, the effects on watersheds if a well pad is not successfully 

reclaimed. Cumulative impacts are those that result from the incremental impact of an action when added 

to other past, present, and reasonably foreseeable future actions. Direct and indirect impacts of the CD-C 

project are described in this chapter; cumulative impacts are described in Chapter 5. Throughout the EIS, 

the words impact and effect are used interchangeably. 

The CEQ regulations also call for a discussion of the significance of the impacts. Significance requires 

considerations of both context and intensity. Significance can vary dependent on the setting in which the 

Proposed Action and the alternatives are to take place. Each resource section in this chapter includes a 

brief description of the considerations made in determining the significance of the environmental effects 

for the resource under discussion. 

The regulations also direct the resource specialist to describe ways in which adverse environmental 

impacts may be mitigated. For the Proposed Action and all of the alternatives, a broad set of discretionary 

mitigation measures would be applied when appropriate as a matter of course by the BLM. These 

measures are frequently referred to as Best Management Practices (BMPs) and are often applied by the 

BLM as Conditions of Approval (COAs) on natural gas Applications for Permit to Drill (APDs). BMPs 

that may be applicable to the CD-C project and the standard set of oil and gas COAs applied by the 

Rawlins Field Office (RFO) are described in Appendix C. The Rawlins Resource Management Plan 

(RMP) also contains descriptions of BMPs that could be applied by the BLM as necessary. Each resource 

section may contain additional recommended mitigation measures if the resource specialist determines 

that mitigation measures in the standard suite of BMPs would not be sufficient. 

The Proposed Action and five alternatives are considered in this document. The requirements of each of 

the alternatives apply only to public lands administered by the BLM and to federal mineral estate. 

	 The Proposed Action. The Operators propose to drill up to 8,950 additional natural gas wells 

throughout the CD-C project area, on public and private mineral estate, over 15 years, with a project 

life of up to 55 years. About 42 percent of the 8,950 new wells would be directional wells from 

multiple-well pads. One result of directional drilling is reduced surface disturbance per well bore. 

	 Alternative A: 100-Percent Vertical Drilling. This alternative (and all the other action 

alternatives) would also include up to 8,950 additional wells in the project area. However, it is 

assumed that directional drilling would not be used at all―that there would be no multiple-well 

pads―and that consequently project surface-disturbance would be greater than for the Proposed 

Action. 

	 Alternative B: Enhanced Resource Protection. The Enhanced Resource Protection Alternative 

requires protections and mitigation beyond the measures ordinarily applied for certain resources that 

are of high value or may be at greater risk of adverse impacts, such as pronghorn and mule deer 

crucial winter range. The alternative also describes surface disturbance and species population 

thresholds that, if crossed, would signal the need for still more protections and mitigation and 

outlines the additional measures that may be needed. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 4-1 
CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—INTRODUCTION
 

	 Alternative C: Surface Disturbance Cap—High and Low Density Development Areas. This 

alternative places a cap of 60 acres per section on the amount of unreclaimed surface disturbance on 

public land in those parts of the CD-C project area that have had high-density development. For the 

remainder of the project area—the low-density development areas—the cap on surface disturbance 

would be 30 acres per section. All prior surface disturbance committed to long-term use for roads or 

on-pad production facilities and all disturbance that had not been successfully reclaimed would 

count against the cap. Acreage that had successfully undergone interim reclamation would not count 

against the cap. 

	 Alternative D: Directional Drilling. This alternative requires that all future natural gas wells on 

federal mineral estate be drilled from multi-well pads, which would require the use of directional 

drilling technology to reach targeted downhole locations. One new multi-well pad per section (or 

per lease if the lease area is less than a section) would be permitted. In sections that have already 

had oil and gas development, the enlargement of one existing well pad would be permitted as the 

multi-well pad for all future drilling in that section. No new roads or pipeline routes would be 

permitted. In sections that have not had oil and gas development at all, one new well pad would be 

permitted for all future development. One road and pipeline corridor per well pad would be 

permitted. Under certain conditions, Operators may request that an APD be excepted from the 

general rule. 

	 Alternative E: No Action. Under the No Action Alternative, it is assumed that none of the natural 

gas development activities proposed by the CD-C Operators would occur. The analysis of the No 

Action alternative assumes that previously authorized activities would continue but that no new 

development would take place under this proposal. 

The Proposed Action and alternatives are described in more detail in Chapter 2, Alternatives Including 

the Proposed Action. None of the alternatives is designated as the BLM’s preferred alternative. The 

BLM NEPA Handbook (H-1790-1) calls for expression of the BLM’s preferred alternative in the Draft 

EIS if one exists (BLM 2008c). The BLM does not have a preferred alternative for the CD-C Natural Gas 

Development Project at this time. The BLM believes that the Proposed Action and the action alternatives 

all have elements that would address the project purpose and need and will review public comment on the 

Draft EIS before determining a preferred alternative. A preferred alternative will be designated in the 

Final EIS. 

4.0.2 Historic and Future Impacts 

The CD-C natural gas development project is an in-fill project. This means that future natural gas 

development in the project area would be a continuation of activity that has been ongoing there for some 

time. Natural gas exploration and development in the Continental Divide-Creston area began in the 1950s. 

The Wamsutter field was the first field established in the area, in 1958, followed by the Creston field in 

1960, the Continental Divide field in 1964, and the Blue Gap field in 1974. Since initiation of drilling, 

about 4,400 natural-gas wells have been drilled in the project area. Map 4.0-1 displays the locations of 

those wells. The annual rate of development increased from the late 1990s until 2008 when 304 gas wells 

were drilled. Since then, drilling has proceeded at a rate of about 200 wells per year. 

This previous natural gas development has generated substantial surface disturbance. As shown in Table 

4.0-1, oil and gas development in the project area prior to 2006 had resulted in the disturbance of an 

estimated 49,218 acres, of which 8,472 acres remain unvegetated and in use for facilities such as well pad 

access roads, well-production facilities, and pipeline facilities. The many pipelines that cross the area 

contributed about half the historic surface disturbance—over 26,500 acres. Wamsutter is a major pipeline 

hub that serves many natural gas pipelines, all of which cross the CD-C project area. An additional 10,958 

acres were disturbed for purposes other than oil and gas development, principally federal, state, and 

county highways and roads, but also ranching and agricultural activities. Taken together, these figures 

indicate that 5.6 percent of the surface of the CD-C project area’s 1.1 million acres has been disturbed at 

4-2 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—INTRODUCTION
 

some time in the past. Depending on the success of reclamation efforts, about 42,500 acres of that initial 

disturbance are in various stages of ecological restoration. 

Map 4.0-1 displays the spread and the density of the past natural gas surface disturbance. Individual 

sections are color-coded from dark green to red according to the amount of surface disturbance that has 

occurred in the section. Dark green represents a section that has seen no disturbance at all; red represents 

a section that has had more than 75 acres of disturbance (12 percent or more of the surface area of the 

section). 

For the most part, the greatest disturbance is located in the same areas with the greatest amount of 

drilling. The exceptions are those sections that have major industrial facilities. The past development and 

the disturbance have primarily been located in the central part of the project area, along either side of the 

Wamsutter Road, south of I-80, and on either side of the Crooks Gap Road, north of I-80. Large areas in 

the northeast and the western parts of the project area have seen relatively little development. 

Table 4.0-1 also shows the additional disturbance that would be generated by the Proposed Action and 

each alternative. Displayed immediately below the figures for the initial and long-term disturbance that 

would be produced by each alternative are the comparable figures for the combined initial disturbance 

(Combined IN) and the combined long-term disturbance (Combined LT) of previous actions and those of 

the alternative. 

Adding the estimated 47,200-acre disturbance associated with the Proposed Action to the 60,176 acres 

previously disturbed would mean that ten percent of the project area―107,376 acres―would be disturbed 

by the time the Proposed Action is completed. To the extent that past reclamation efforts have been 

successful and that future reclamation is also successful, a minimum of 3.4 percent―36,524 acres―of the 

lands within the project area would remain in an unvegetated state on a long-term basis (the Combined LT 

disturbance). 

The CD-C project area is managed under the provisions of Federal Land Policy and Management Act for 

multiple use. Range, minerals, recreation, wild horses, wildlife, and other resources and uses are 

considered in the BLM’s management of the federal lands and balance is sought between them. 

Rangeland health assessments are guided by the “Standards for Healthy Rangelands and Guidelines for 

Livestock Grazing Management for the Public Lands” (Standards and Guidelines) (BLM 2001a). The 

Standards apply to all resource uses for public lands including oil and gas development. Guidelines 

provide for, and guide the development and implementation of, reasonable, responsible, and cost-effective 

management practices at the grazing allotment and watershed level. 

There are two primary watersheds within the CD-C area. If a watershed assessment reveals that a 

Standard(s) is not being met, factors contributing to the non-attainment are identified and management 

recommendations are developed so the Standard(s) may be attained. When a Standard(s) is failed, 

corrective action must be taken by whatever permitted entity is causing the failure. During the CD-C 

implementation period, any failures to attain Standards may be due to ranching practices, oil and gas 

development activities, other activities that have been permitted, or a combination of many factors. If oil 

and gas operators are found to be causing or contributing to non-attainment of a standard, the BLM will 

require their participation and contribution to corrective actions that may be required. Further monitoring 

and adaptive management may be required from any parties contributing to the problem. This provision 

applies to all rangelands/habitat found within the project area. Close cooperation between the BLM, range 

permittees, oil and gas companies, and perhaps others may be required to successfully attain any 

Standards that are not being met. The environmental effects assessed in this chapter take into account 

compliance with the Standards and Guidelines and related periodicmonitoring of rangelands. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 4-3 
CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—INTRODUCTION
 

Map 4.0-1. Past surface disturbance, by section, within the CD-C project area 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

4-4 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
 

 

CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—INTRODUCTION 

Table 4.0-1. CD-C surface disturbance – historic, Proposed Action and Alternatives (acres) 

Category 

Surface Disturbance 

Oil and Gas 

Grand 

Total 

Percent of 

Project 

Area 

Change from Proposed 

Action 

Well Pads 

(incl. 

roads) 

Related 

Facilities1 Total acres % 

Historical 

Initial 

Long-term 

20,524 28,694 49,218 60,176 5.6% — — 

6,403 2,069 8,472 17,663 1.7% — — 

Proposed Action 

Initial 

Long-term 

Combined IN2 

Combined LT2 

41,889 5,311 47,200 47,200 4.4% — — 

17,998 863 18,861 18,861 1.8% — — 

62,413 34,005 96,418 107,376 10.0% — — 

24,401 2,932 27,333 36,524 3.4% — — 

Alternative A: 100-Percent Vertical Drilling 

Initial 

Long-term 

Combined IN2 

Combined LT2 

56,385 5,311 61,696 61,696 5.8% 14,496 30.7% 

23,270 863 24,133 24,133 2.3% 5,272 28.0% 

76,909 34,005 110,914 121,872 11.4% 14,496 13.5% 

29,673 2,932 32,605 41,796 3.9% 5,272 14.4% 

Alternative B: Enhanced Resource Protection Alternative 

Initial 

Long-term 

Combined IN2 

Combined LT2 

40,205 5,311 45,516 45,516 4.3% -1,684 -3.6% 

17,386 863 18,249 18,249 1.7% -611 -3.2% 

60,729 34,005 94,734 105,692 9.9% -1,684 -1.6% 

23,789 2,932 26,721 35,912 3.4% -611 -1.7% 

Alternative C: Cap on Surface Disturbance, 60 Acres and 30 Acres per Section 

Initial 

Long-term 

Combined IN2 

Combined LT2 

37,644 5,311 42,955 42,955 4.0% -4,245 -9.0% 

16,455 863 17,318 17,318 1.6% -1,543 -8.2% 

58,168 34,005 92,173 103,131 9.6% -4,245 -4.0% 

22,858 2,932 25,790 34,981 3.3% -1,543 -4.2% 

Alternative D: Directional Drilling 

Initial 

Long-term 

Combined IN2 

Combined LT2 

31,138 5,311 36,449 36,449 3.4% -10,751 -22.8% 

14,089 863 14,952 14,952 1.4% -3,908 -20.7% 

51,662 34,005 85,667 96,625 9.0% -10,751 -10.0% 

20,492 2,932 23,424 32,615 3.0% -3,908 -10.7% 

Alternative E: No Action 

Initial 

Long-term 

Combined IN2 

Combined LT2 

0 0 0 0 0.0% -47,200 -100.0% 

0 0 0 0 0.0% -18,861 -100.0% 

20,524 28,694 49,218 60,176 5.6% -47,200 -44.0% 

6,403 2,069 8,472 17,663 1.7% -18,861 -51.6% 

1

 Estimated future disturbance is unchanged under each alternative for “Related O&G Facilities,” except for No Action, which has no 

disturbance. 

2

 “Combined IN” equals the sum of historic initial disturbance and future initial disturbance. 

 “Combined LT” equals the sum of historic long-term disturbance and future long-term disturbance. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 4-5 
 

CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—INTRODUCTION
 

Alternative A, 100-Percent Vertical Drilling, would result in the greatest surface disturbance—61,696 

acres—a 31 percent increase over the Proposed Action. When combined with previous disturbance, 11.4 

percent of the project area―121,872 acres―would be disturbed by the time Alternative A is 

implemented. A minimum of 3.9 percent―36,524 acres―of the lands within the project area, the 

Combined LT disturbance, would remain in an unvegetated state on a long-term basis. The remaining 

action alternatives, Alternatives B through D, would each produce successively less surface disturbance 

than either the Proposed Action or Alternative A. Alternative B, Enhanced Resource Protection, would 

generate an estimated initial disturbance of 45,516 acres, 3.6 percent less than the Proposed Action. 

Alternative C, Cap on Surface Disturbance, would generate an estimated initial disturbance of 42,955 

acres, 9.0 percent less than the Proposed Action. Alternative D, Directional Drilling, would produce the 

lowest initial surface disturbance—an estimated 36,499 acres—and a 22.8 percent reduction from the 

Proposed Action. It would also produce the lowest combined initial disturbance—96,625 acres—and the 

lowest combined long-term disturbance—32,615 acres. Alternative E, No Action, would produce no new 

disturbance and thus no addition to the previous totals. 

Another indicator of the degree of disturbance that an alternative would generate is the number of well 

pads likely to be used to implement the Operators’ drilling plans. The Proposed Action and all the action 

alternatives would each permit the drilling of the proposed 8,950 wells but the requirements of the 

alternatives would alter the degree to which directional drilling is used and therefore the number of 

wellpads. As indicated earlier, the Proposed Action assumes that about 42 percent of the 8,950 wells 

would be drilled using directional techniques from multi-well pads. A total of 6,126 well pads is implied. 

Table 4.0-2 shows the estimated number of well pads that would be used in each of the alternatives. 

Alternative A assumes only vertical drilling would apply so the number of well pads is the same as the 

number of wells: 8,950. Under Alternative D, it is estimated that virtually all wells drilled to federal 

mineral estate would be drilled from a multi-well pad, with the construction of an estimated 4,032 well 

pads, a 34.2 percent reduction from the Proposed Action. The relative distribution of vertical and 

directional wells on private and state minerals would remain unchanged. 

Table 4.0-2. CD-C estimated well pad numbers by alternative 

Alternative Well Pads % Change 

Proposed Action 6,126 — 

Alternative A: 100-Percent Vertical Drilling 8,950 46.1% 

Alternative B: Enhanced Resource Protection 5,798 -5.4% 

Alternative C: Surface Disturbance Cap 5,299 -13.5% 

Alternative D: Directional Drilling 4,032 -34.2% 

Alternative E: No Action 0 -100.0% 

The amount of surface disturbance generated by the project is an important indicator of the overall level 

of direct impacts that would be produced. This figure is directly related to the soils, watershed, and 

vegetation impacts that would result from the project. The number of well pads used to drill out the 

project is also an important indicator, not only because it is a major determinant of the amount of surface 

disturbance needed, but also because it indicates the number of sites that will be disturbed and the degree 

to which the landscape would be fragmented by the well sites and the access roads to them. Each 

disturbance site is also the focal point of impacts that extend outward from the site and the fewer the 

number of sites, the less these impacts would be felt. The presence of industrial facilities, in particular the 

noise and the regular human activity associated with the sites, alters the way that the surrounding 

landscape serves as wildlife habitat. For example, not only is browse and forage removed by construction 

of a well pad, but access to forage may be inhibited by the noise, activity, and dust produced around a 

well pad. The impact may differ for each species. In terms of wildlife impacts, the effect is generally 

captured by the term “habitat fragmentation.” It is not just a wildlife phenomenon, however, as the same 

4-6 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—INTRODUCTION
 

factors apply to visual and recreation resources, grazing management, watershed management, and other 

resources. 

Past disturbance is a direct indicator of the degree to which environmental and human resources in the 

project area have already been affected. It represents changes to the visual environment, wildlife habitat, 

transportation system, recreation, and other resources that are already in place. Unlike analyses of other 

projects where there has been little or no prior development, the impact analysis of future development in 

the CD-C project area must be described in the context of the substantial impacts that have already 

occurred. 

Two examples illustrate the ways in which the analysis of future impacts can be altered by impacts that 

have already taken place. 

	 Visual impacts are generally discussed in terms of the degree to which a proposal would alter the 

natural visual environment. In the case of the CD-C project area, past development has already 

introduced a substantial industrial element into many viewsheds in the area. This is reflected in the 

Rawlins RMP’s current classification of its visual resources and therefore the level of landscape 

change future actions would be allowed to have. The Rawlins RMP’s current land classifications 

(expressed as Visual Resource Management, or VRM, classes) are the basis for the visual resources 

analysis presented in this chapter (see Section 3.11.3). 

	 The transportation system and the traffic it carries is often a major cause of environmental impacts 

produced by a natural gas development project. In the CD-C project area, most of the collector and 

arterial roads and many of the local roads that would be needed for full-field development have 

already been constructed and are in use. This means that the disturbance associated with future road 

construction would be substantially less than if the infrastructure were not already in place. On the 

other hand, the wildlife habitat fragmentation and disturbance associated with natural-gas access 

roads and traffic is already a fact in much of the area. The analysis of impacts on wildlife reflects 

this existing state. 

4.0.3 Distribution and Density of Future Impacts 

The Proposed Action does not define the specific locations of any natural gas wells or associated facilities 

proposed for the CD-C project area. The analysis of impacts described in this chapter assumes that facility 

construction and well-drilling could occur anywhere within the project area and that all parts of the area 

would be affected. However, the historic development in the project area provides an indicator as to the 

likely spatial distribution and density of future development. 

Map 4.0-2 shows the locations of natural gas wells drilled to date in the CD-C project area and the 

current well spacing designated by the Wyoming Oil and Gas Conservation Commission (WOGCC) 

throughout the project area. Spacing refers to the spatial density of wells per section (640 acres) 

producing from the same reservoir, usually stated in terms of acres. It is a formal designation that has 

been approved by the WOGCC. In Map 4.0-2, the currently approved spacing in the yellow areas is 160 

acres, meaning one well is permitted in each 160-acre parcel. Currently approved spacing in the orange 

areas is 80 acres (one well per 80 acres) and in the red areas is 40 acres, with a variant in some parcels— 

pink—that is about 60 acres. 

Spacing designations refer not to the number of surface locations of the wells (well pads) but to the 

number of down-hole (bottom-of-hole) locations. Thus, an 80-acre spacing that allowed for eight wells 

per section could result in as many as eight well pads or as few as one, if all wells were drilled from the 

same pad. If all wells in this example were drilled from their own individual pad, 50 or more acres of 

surface disturbance could result (at 6.3 acres of disturbance per well pad). However, with application of 

directional drilling techniques, perhaps only one or two surface locations (well pads) per section would be 

needed, and the resultant surface disturbance could be 20 acres or less. A central feature of Alternatives C 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 4-7 
CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—INTRODUCTION
 

and D is the effort to constrain the number of surface locations used to achieve the down-hole locations 

rather than the number of down-hole well locations. 

Generally, spacing units reflect the judgment of the Operators—with WOGCC concurrence—as to the 

number of wells that would be required to efficiently develop and recover the natural gas resource in an 

area. It is not uncommon to begin development of a field with relatively low well spacing, e.g., one well 

per 160 acres, and then seek approval from WOGCC for “tighter” spacing to 80 acres, 40 acres, or less, as 

production occurs and more is learned about the gas reservoir. As the map shows, the “tightest” spacing is 

in the areas with the greatest number of wells. As the CD-C’s natural gas resource was developed over the 

last six decades, operators determined that more wells would be needed to fully recover the gas and so 

more dense spacing was sought by the operators and approved by the WOGCC. 

The analysis of impacts in the CD-C project area assumes that the spacing units depicted in Map 4.0-2 

would likely be realized as the area’s natural gas resource is developed. That means that at full 

development, in areas with 40-acre spacing, there would be one well every 40 acres, or 16 wells per 

section. Areas with 80-acre spacing would have eight wells per section and areas with 160-acre spacing 

would have four wells per section. In general terms, that would result in the most intense future 

development occurring on either side of the Wamsutter and Crooks Gap Roads in the central part of the 

CD-C project area as those areas that have seen the most development to date are “filled in.” The areas 

surrounding this area of intense development would also be “filled-in” but with lower density: eight wells 

per section. The remainder of the project area would see less-intense development with its 160-acre 

spacing, or potentially four wells per section. 

The analysis assumption anticipates that, as development proceeds, some operators are likely to conclude 

that full development of the natural gas resource in certain parts of the CD-C project area requires tighter 

spacing. In those cases, they would request a reduction from 160-acre spacing to 80-acre spacing, or from 

80-acre to 40-acre spacing, with well densities increasing from four to eight wells per section or from 

eight to 16 wells per section. The areas where this might occur cannot be predicted but such increases in 

density are within the scope of the analysis. 

While the same number of wells is proposed for the Proposed Action and Alternatives A through D, the 

disturbance area for each would vary according to the degree to which directional drilling is pursued. 

Directional drilling allows more than one well to be drilled at a location, resulting in an estimated average 

initial disturbance of 2.45 acres per well bore, including both an allowance for the well pad and for the 

access road to the location. For a vertically drilled well, the estimated initial disturbance would be 6.3 

acres per well, including well pad and access road. The total estimated disturbance for each alternative is 

shown in Table 4.0-1. Since Alternative A, 100-Percent Vertical Drilling, has no directional drilling, it 

has the highest total surface disturbance, an estimated 61,696 acres. The Proposed Action, with an 

estimated 42-percent directional drilling component, would produce an initial surface disturbance of 

47,200 acres. Alternatives B through D have successively less surface disturbance as the amount of 

directional drilling increases with each. Alternative E, No Action, would have no drilling and no surface 

disturbance at all. 

4-8 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—INTRODUCTION
 

Map 4.0-2. Current well spacing orders in the CD-C project area 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—GEOLOGY 

 PHYSICAL ENVIRONMENT 

4.1 GEOLOGY 

4.1.1 Introduction 

Of the geological features described in Section 3.1 Geology, the surface environment would be impacted 

by the Proposed Action and the action alternatives, affecting the geology of the CD-C project area and 

causing mass movement, a geological hazard. Removing vegetation and soils could lead to altered 

hydrology, decreased infiltration rates, and increased overland flow rates. Unmitigated, accelerated 

erosion could cause gullying in some areas and rapid deposition or siltation in other areas with associated 

erosion effects. Mass movements, including landslides, could be triggered in areas that become oversteepened by erosional removal of slope-supporting material. Altering existing topography, particularly 

by steepening slopes, could also trigger mass movements and accelerated erosion. 

The magnitude of impacts to the geology and associated geological hazards in the project area would be 

reduced by the implementation of mitigation measures for geology, soils, vegetation, and water resources 

as described in Appendix C. 

4.1.2 Management Objectives and Impact Significance Criteria 

The Rawlins RMP (BLM 2008a) prescribes no management objectives or significance criteria for 

geology. 

The following significance criterion for geology was adapted from the Atlantic Rim Field Development 

Natural Gas Development Project Final EIS (BLM 2006a): 

1.	 Impacts to geology would be significant if project implementation results in increased runoff and 

erosion that leads to mass movement (including landsliding), subsidence, flooding, or increased 

deposition or siltation that alters the landscape. 

4.1.3 Direct and Indirect Impacts 

4.1.3.1 Impacts Common to All Action Alternatives 

Impacts could occur to the geologic environment caused by project implementation and operation (e.g., 

alteration of existing topography, initiation of mass movements, including landslides). Impacts could 

occur to project facilities as a result of inherent geologic hazards. The likelihood of these impacts 

occurring as a result of project implementation is remote, particularly with adoption of the mitigation 

measures for geology, soils, vegetation, and water resources described in Appendix C and adherence to 

Wyoming Department of Environmental Quality (WDEQ) and WOGCC requirements. The potential for 

impacts depends on where surface disturbance occurs and the total amount and distribution of disturbance 

both spatial and temporally. 

4.1.3.2 Proposed Action and Alternatives 

Impacts to the geological environment would be more likely with alternatives that have the greatest 

amount of concentrated (spatially and temporally) surface disturbance. The Proposed Action and the 

Alternatives would result in differing amounts of initial and long-term ground disturbance, largely 

because of varying numbers of wells drilled directionally from multiple-well pads. The Proposed Action, 

with mixed vertical and directional drilling, would produce 47,200 acres of disturbance. Alternative A has 

only vertical drilling and consequently would result in an estimated 61,696 acres of disturbance, a 30­

percent increase (Table 4.0-1). Because surface disturbance would be greater, Alternative A would have a 

greater chance of impacting the geological environment. Alternatives B, C, and D would each have 

4-10 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
 

 

CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—GEOLOGY 

decreasing levels of surface disturbance and hence decreasing risks of impact. Alternative E, No Action, 

would have no potential for impacts. With application of appropriate mitigation measures, the 

significance criterion would not be met. 

4.1.4 Impact Summary 

While the likelihood of geological impacts occurring as a result of project implementation is remote, the 

Proposed Action and all of the alternatives have the potential for direct and indirect impacts to geology to 

the extent that the ground is disturbed by development activities. Successful application of mitigation 

measures described in Appendix C would minimize the risk of those impacts occurring and remove the 

likelihood of meeting the significance criterion. 

4.1.5 Unavoidable Adverse Impacts and Additional Mitigation Measures 

Mitigation measures for geology, soils, vegetation, and water resources described in Appendix C would 

avoid or minimize impacts to the surface geologic environment and lessen the possibility of mass 

movement and flooding; therefore, no additional mitigation measures are necessary. 

4.2 PALEONTOLOGIC RESOURCES 

4.2.1 Management Objectives and Impact Significance Criteria 

The Rawlins RMP (BLM 2008a) prescribes the following management objectives associated with 

paleontology: 

 Identify paleontological resources by defining priority inventory areas based on probability of 

occurrence of high-value resources. 

 Assess the need for project or site-specific treatment plans or other protective measures in areas of 

high risk for development or at high risk for adverse effects. 

 Develop, maintain, and encourage opportunities for scientific research of paleontological resources. 

 Provide educational opportunities and public outreach programs. 

 Develop and maintain interpretation of paleontological resources in areas of high public interest and 

access. 

Impacts to paleontological resources would be considered significant if the following were to occur: 

1.	 An action or development causes substantial direct or indirect damage or destruction to important 

paleontological resources. 

4.2.2 Direct and Indirect Impacts 

4.2.2.1 Impacts Common to All Action Alternatives 

Excavation of pipeline trenches and construction of well pads, access roads, and ancillary facilities 

associated with the Proposed Action or its alternatives could result in the exposure and possible 

destruction of paleontological resources (frequently referred to here as fossils or fossil resources), either 

directly as a consequence of construction or indirectly as a result of increased erosion rates. Increased 

access resulting from development may increase the visibility of fossil resources and lead to increased 

illegal fossil collection. The potential for impacts increases in areas where geological formations rated as 

having a moderate to very high PFYC (3, 4, or 5) are exposed at the surface or shallow enough to be 

affected by excavation. The CD-C project area is underlain by geological units that have a moderate to 

very high potential of producing scientifically important fossils. These units (with their PFYC in 

parentheses) include the Battle Spring (3), Fort Union (3), Green River (5) and Wasatch (5) formations. 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—GEOLOGY 

Excavation of pipelines and construction of other project facilities could also result in the discovery of 

new paleontological resources. If these newly discovered resources are properly recovered and catalogued 

into the collections of a museum repository, the Proposed Action and its alternatives could result in a 

better understanding and knowledge of this resource. In addition, increased access would allow easier 

access by professional, permitted paleontologists and geologists, who hope to make scientifically 

significant discoveries. 

Implementation of mitigation measures described in Appendix C would lessen the chance that 

scientifically important fossils would be damaged or destroyed directly or indirectly. The Paleontological 

Resource Preservation Act (PRPA) described in Section 3.2.1 broadened the guidance for surveying for 

paleontological resources and mitigating potential impacts. That guidance is captured in BLM Instruction 

Memorandum [IM] No. 2009-011, Assessment and Mitigation of Potential Impacts to Paleontological 

Resources (BLM 2008d). The IM is summarized here and is included in its entirety in Appendix D, 

Paleontological Resources Program Guidance. 

IM 2009-011 calls for the BLM to assess the possible effects on paleontological resources of all 

proposed surface-disturbing activities on public lands or split-estate lands. If the assessment indicates 

“(a) the presence or high probability of occurrence of vertebrate fossils or uncommon nonvertebrate 

fossils (PFYC Class 4 or 5), or that the probability is unknown (Class 3), in the area of a proposed 

federal action or transfer of title, and (b) a reasonable probability that those resources will be 

adversely affected by the proposed action,” then measures such as a field survey, onsite monitoring, 

special stipulations, avoidance, or other mitigation may be required. 

The preferred mitigation technique is to change the project location based on the results of the field 

survey. Monitoring may be required as part of overall mitigation for a project, arising out of the 

NEPA process, or upon the discovery of paleontological resources during project activities. The 

purpose of onsite monitoring is to assess and collect any previously unknown fossil material 

uncovered during the project activities or soon after surface-disturbing actions. 

4.2.2.2 Proposed Action and Alternatives 

Impacts to paleontological resources would be more likely with alternatives that have the greatest amount 

of concentrated surface disturbance, both spatially and temporally. The Proposed Action and the 

alternatives would result in differing amounts of initial and long-term ground disturbance, largely because 

of varying numbers of wells drilled directionally from multiple-well pads. The Proposed Action, with 

mixed vertical and directional drilling, would produce 47,200 acres of disturbance. Alternative A would 

have only vertical drilling and consequently would result in an estimated 61,696 acres of disturbance, a 

30-percent increase (Table 4.0-1). Alternatives B, C, and D would each have decreasing levels of surface 

disturbance—with 45,516 acres, 42,955 acres, and 36,449 acres respectively—and hence decreasing risks 

of impact. Because surface disturbance would be greater, Alternative A would have the greatest chance of 

impacting paleontological resources. Under Alternative E, No Action, no paleontological impacts would 

occur in the CD-C project area. With application of appropriate mitigation measures, the significance 

criterion would not be met. 

4.2.3 Impact Summary 

Implementation of the Proposed Action or the alternatives has the potential to impact paleontological 

resources to the extent that the ground is disturbed by development activities. Successful application of 

mitigation measures described in Appendix C and Appendix D would minimize and mitigate these 

impacts and remove the possibility of causing substantial direct or indirect damage or destruction to 

important paleontological resources. The significance criterion would not be met. 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—GEOLOGY 

4.2.4 Unavoidable Adverse Impacts and Additional Mitigation Measures 

Because the potential for substantial adverse impacts on important paleontological resources would be 

minimized by the mitigation measures described in Appendix C and in Appendix K, no additional 

mitigation measures would be necessary. 

4.3 SOILS 

4.3.1 Introduction 

Impacts to the soil resource resulting from construction and installation of well pads and wells, access 

roads, pipelines, and compressor stations include the removal of vegetation and soil, exposure of soil, soil 

compaction, and undesirable mixing of soil horizons. In addition, saline and/or sodic soil conditions could 

be created from the release of fracturing fluids, drilling fluids, or produced water. These impacts could 

subsequently result in a loss of soil productivity, increased susceptibility of the soil to wind and water 

erosion, increased surface runoff, increased sedimentation and elevated salt loads within project area 

water resources, and the spread of invasive/noxious plants. 

4.3.2 Management Objectives and Impact Significance Criteria 

The Rawlins RMP (BLM 2008a) lists the following management objectives associated with the soil 

resource: 

 Soils should be stable and allow for water infiltration to provide for optimal plant growth and 

minimal surface runoff. 

 Soil productivity should be maintained.
 

The following criteria serve as a basis to assess the intensity, duration, and magnitude of soil impacts 

associated with implementation of the Proposed Action and action alternatives. Soil impacts would be 

considered significant if: 

1.	 Soil productivity is reduced to a level that prevents the disturbed area from recovering to predisturbance soil/vegetation productivity levels; 

2.	 Reclamation monitoring does not indicate a trajectory towards success within two to five years of 

reclamation; or 

3.	 Disturbed areas are not adequately stabilized to reduce soil erosion, surface runoff, and associated 

impacts to water quality. 

4.3.3 Direct and Indirect Impacts 

Impacts to the soil resource under the Proposed Action and all alternatives include removal of vegetation 

and soil, exposure of soil, soil compaction, undesirable mixing of soil horizons, and the creation of saline 

and/or sodic soil conditions. 

Removal of Vegetation and Soil Resulting in Exposure of Soil. Removal of vegetation and soil during 

construction and production activities, and the subsequent exposure of the soil, can lead to increased 

susceptibility to erosion and loss of soil productivity. Soils are more susceptible to erosion if they are not 

protected by vegetation cover or are left exposed to wind or water flow. This is exacerbated during 

intensive storm events, floods, or drought conditions. Removal of vegetation and litter from the 

construction/production sites removes organic material that eventually could become soil organic matter. 

Loss of topsoil, from removal during construction or production activities or from erosion, can result in 

the loss or reduction of soil organisms, viable seed-bank, and soil nutrients. Finally, exposed soils are 

more susceptible to invasive plant establishment. The effects of vegetation and soil removal and exposed 

soils can be minimized through the implementation of proper soil-salvaging techniques and prompt 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 4-13 
CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—SOILS 

attention to soil stabilization (see the Rawlins RMP Record of Decision (ROD), Appendix 36 [BLM 

2008b]). 

Soil Compaction. Soil compaction from construction and production activities on the disturbed areas can 

reduce soil productivity and increase surface runoff. Soil compaction affects soil structure and reduces 

pore size. Excessive compaction can lead to reduced water infiltration into the soil and reduced 

permeability of water through the soil; reduced diffusion of oxygen, carbon dioxide, and other gases into 

and out of the soil; reduced plant-root penetration; and reduced plant growth and production. The effects 

of compaction can be reduced at the time of reclamation through sound site-preparation practices, 

including ripping. 

Undesirable Mixing of Soil Horizons. Loss of soil productivity could result when construction and 

production activities disturb the soil resource. The mixing of soil horizons, where subsurface soil horizons 

are brought to the surface and mix with or replace surface-soil horizons, can result in less biologically 

productive surface soils. Soil-horizon mixing can result in elevated soil pH, increased soil salinity, higher 

sodium and calcium carbonate concentrations, decreased levels of soil nutrients and organic matter, and 

altered soil structure, texture, and rock content. The effects of soil mixing can be minimized or eliminated 

through proper soil salvaging (see the Rawlins RMP ROD, Appendix 36 [BLM 2008b]). 

Creation of Saline/Sodic Soil Conditions. Spilled fracturing fluids, drilling fluids, and produced water 

could lead to loss of soil productivity through the creation of saline/sodic soil conditions at production 

facilities during construction and production activities. Depending on the size and type of spill, the effect 

on soils would vary considerably. Saline soils can interfere with plant germination and growth, and sodic 

soils can become hard and crusted with effects similar to those of compacted soils. The effects of spilled 

fracturing fluids, drilling fluids, and produced water can be minimized through proper implementation of 

the Spill Prevention, Control, and Countermeasure (SPCC) Plan, and the use of approved disposal 

methods for produced water. 

While the types of soil impacts would be similar for the Proposed Action and the action alternatives, the 

impacts of each alternative would vary according to the amount of surface disturbance and the 

effectiveness of reclamation efforts. Impacts to soils are assumed to be proportional to the amount of new 

surface disturbance for each alternative (i.e., increased disturbance would result in a proportionate 

increase in adverse impacts to soils). To a great extent, the amount of surface disturbance is directly 

correlated with the degree to which directional drilling is pursued in an alternative, since directional 

drilling results in an estimated average initial disturbance of 2.45 acres per well bore, including well pad 

and access road, while the average vertical well produces 6.3 acres of initial disturbance. Section 4.0.2, 

Historic and Future Impacts, in Table 4.0-1, provides detailed information on the estimated disturbance 

by alternative. Section 4.0.2 also describes the extent of past surface disturbance in the CD-C project area. 

Historic disturbance in the area amounts to an estimated 60,176 acres, almost 82 percent—49,218 acres— 

of which is related to historic oil and gas development. All of the surface disturbance and soil impacts 

described in the subsections below would be in addition to those that have already occurred. 

In general, the extent of impacts to the soil resource would be greatly influenced by the success of 

mitigation and reclamation efforts. Emphasis would be placed on the stabilization of disturbed soils, 

particularly via the establishment of vegetative ground-cover during the first growing season following 

disturbance. Reclamation potential of soils in the CD-C project area is primarily poor with major 

limitations being saline/sodic soil conditions and either clayey or sandy soil textures (Table 3.3-1). In 

addition to these soil limitations, low annual precipitation of 10–14 inches in conjunction with erosion by 

wind and water could make successful reclamation more difficult to attain. Revegetation may be 

challenging on the estimated 75 percent of the project area indicated as possessing fair or poor 

reclamation potential (Table 3.3-1). However, current technology exists to stabilize disturbances, 

minimize erosion, and increase reclamation success provided that construction, maintenance, and 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—SOILS 

operation of well pads and associated disturbances are in accordance with planned mitigation measures 

and reclamation. 

For the Proposed Action and Alternatives, strict adherence to the Rawlins RMP and required Conditions 

of Approval and Best Management Practices (Appendix C) is vital to minimize impacts to sensitive soils. 

Included in the RMP guidance are Appendix 1 – Wyoming Bureau of Land Management Mitigation 

Guidelines for Surface Disturbing and Disruptive Activities, Appendix 13 – Reducing Nonpoint Source 

Pollution with Best Management Practices, Appendix 15 – Best Management Practices for Reducing 

Surface Disturbance and Disruptive Activities, and Appendix 36 – Reclamation Plan (BLM 2008b). In 

accordance with RMP Appendix 36, each Operator will be required to develop and submit to the BLM for 

approval a site specific reclamation plan for each well location that describes how the Operator will 

achieve the following goals for interim and final reclamation (found in Instruction Memorandum No. 

WYD-03-2011-002): 

 Protection of existing native vegetation; 

 Minimal disturbance of existing environment; 

 Soil stabilization through establishment of ground cover; 

 Establishment of native vegetation consistent with land use planning; and 

 Monitoring and management of the reclamation sites to evaluate reclamation success. 

Full and successful implementation of the above measures would insure that none of the three 

significance criteria would be exceeded. Soil productivity would not be reduced such that pre-disturbance 

conditions could not be recovered, the reclamation trajectory would be toward success, and disturbed 

areas would be adequately stabilized. Failure to successfully implement the required measures could 

produce significant impacts. 

4.3.3.1 Proposed Action 

The Proposed Action would result in adverse soil impacts including the removal of vegetation and soil 

resulting in exposure to erosion, soil compaction, undesirable mixing of soil horizons, and creation of 

saline/sodic soil conditions, directly related to the amount of surface disturbance that would occur. Initial 

(short-term) soil disturbance associated with the construction and operation of 8,950 natural gas wells, 

associated access roads and related facilities is estimated at 47,200 acres (Table 4.0-1). This disturbance 

comprises 4.4 percent of the total project area. Combined with the historic disturbance of 60,176 acres, 10 

percent of the surface of the CD-C project area would be affected. The initial CD-C project-related 

disturbance is considered temporary, as successful interim reclamation is expected to reduce the average 

drill-pad size (including access road) to approximately 40 percent of the initial disturbance area. 

Therefore, during the life of the project (45 to 55 years), the long-term disturbance area is expected to 

decrease to 18,861 acres, or 1.8 percent of the total project area. 

The soils assessment described in Chapter 3 ranked the project area soil limitations related to wind 

erosion, water erosion, runoff potential, road construction potential, and reclamation success (Table 3.3-

1). The current number of wells drilled in each of the rating class areas for each limitation was also 

summarized in the table. 

The distribution of soil limitations for the Proposed Action, assuming that future drilling would occur at 

the same spatial distribution as current wells drilled, is provided in Table 4.3-1. For the 47,200 acres of 

initial disturbance for the Proposed Action, this translates to 34,343 acres with a slight limitation for 

water erosion, 36,656 acres with a moderate limitatiofor wind erosion, 16,775 acres with a moderate 

limitation for runoff potential, 30,115 acres with a moderate limitation for road construction, and 27,095 

acres with a poor reclamation potential. 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—SOILS 

Table 4.3-1. Distribution of soil limitations based on current well locations within the CD-C project area1 

Potential Limitation 

Rating 

Class/Limiting 

Features 

Percentage 

of Existing 

Wells in 

Each Rating 

Class 

ACRES OF DISTURBANCE IN EACH RATING CL

Proposed 

Action 

Alternative A 

100-Percent 

Vertical 

Drilling 

Alternative B 

Enhanced 

Resource 

Protection 

Alternative C 

Cap on 

Surface 

Disturbance, 

High & Low 

Density 

Alt

D

Water Erosion Slight 73.00 34,343 44,890 33,118 31,254 

Moderate 21.00 10,148 13,264 9,786 9,235 

Severe 3.00 1,398 1,827 1,348 1,272 

Not Rated / Water 2.80 1,312 1,714 1,265 1,194 

Wind Erosion Slight 14.00 6,437 8,414 6,207 5,858 

Moderate 78.00 36,656 47,913 35,348 33,359 

Severe 5.90 2,796 3,654 2,696 2,544 

Not Rated / Water 2.80 1,312 1,714 1,265 1,194 

Runoff Potential Low 0.48 224 293 216 204 

Low To Moderate 0.88 414 541 399 377 

Low to High 6.60 3,106 4,060 2,996 2,827 Moderate 36.00 16,775 21,926 16,176 15,266 Moderate to High 30.00 13,962 18,249 13,463 12,706 High 25.00 11,614 15,182 11,200 10,570 Not Rated / Water 2.30 1,104 1,444 1,065 1,005 

Road Construction Limitations Moderate 64.00 30,115 39,364 29,040 27,406 

Moderate / Severe 0.00 0 0 0 0 

Severe 33.00 15,791 20,641 15,227 14,371 

Not Rated / Water 2.70 1,294 1,692 1,248 1,178 

Reclamation Potential Good 14.00 6,454 8,437 6,224 5,874 

Fair 26.00 12,357 16,151 11,916 11,245 Poor 57.00 27,095 35,416 26,128 24,658 Not Rated / Water 2.70 1,294 1,692 1,248 1,178 

Notes 

 Information from two soil surveys completed by the BLM was used to assess the potential limitations of the CD-C project area soils (Texas Resource C

1981). Information from individual soil map units was used to evaluate the soil limitations. If multiple soil series existed within a single map unit, ranking

soil series that comprised the greatest acreage within the unit. 

4-16 Continental Divide-Creston Natural Gas Development Project D

1
CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—SOILS 

Although the extent of areas with soil limitations makes it likely that implementation of the Proposed 

Action would occur on soils that possess severe limitations, total avoidance of these areas would not be 

feasible. Adherence to the Rawlins RMP and required Conditions of Approval (COAs) and Best 

Management Practices (BMPs) (Appendix C) would ensure that disturbed areas are stabilized to reduce 

soil erosion, surface runoff, and associated impacts to water quality, and would minimize the reduction of 

soil productivity. Annual monitoring and adaptation of reclamation practices would be used to establish a 

trajectory to successful reclamation. 

4.3.3.2 Alternative A: 100-Percent Vertical Drilling 

Adverse soil impacts under Alternative A would be similar to the Proposed Action but the extent and the 

degree of the impacts would be greater because the amount of surface disturbance would be greater. The 

construction of 8,950 natural gas wells using only vertical drilling techniques, together with associated 

access roads and related facilities, would produce initial (short-term) soil disturbance estimated at 61,696 

acres, 30.7 percent greater than the Proposed Action. This disturbance would comprise approximately 5.8 

percent of the total project area. Combined with the historic disturbance of 60,176 acres, over 11 percent 

of the surface of the CD-C project area would be affected. The initial CD-C project disturbance is 

considered temporary, as successful interim reclamation is expected to reduce the average drill-pad size 

(including access road) from 6.3 acres to approximately 2.6 acres, reducing the long-term surface 

disturbance to approximately 40 percent of the initial disturbance area. During the life of the project (45 

to 55 years), the long-term disturbance area is expected to decrease to 24,133 acres, or 2.3 percent of the 

total project area. 

While the same number of wells is proposed for both the Proposed Action and Alternative A, the 

disturbance area would be 14,496 acres (30.7 percent) greater for Alternative A because all of the wells 

would be drilled using vertical drilling techniques. With the use of vertical drilling techniques, only one 

well can be drilled at a single location, resulting in approximately 6.3 acres of initial disturbance per well. 

For a directionally drilled well, the initial disturbance would be 2.45 acres per well bore. 

The distribution of soil limitations for Alternative A, assuming that future drilling would occur at the 

same spatial distribution as current wells drilled, is provided in Table 4.3-1. For the 61,696 acres of initial 

disturbance for Alternative A, this translates to 44,890 acres with a slight risk for water erosion, 47,913 

acres with a moderate risk for wind erosion, 21,926 acres with a moderate runoff potential, 39,364 acres 

with a moderate limitation to road construction, and 35,416 acres with a poor reclamation potential 

(Table 4.3-1). 

Although the extent of areas with soil limitations makes it likely that implementation of Alternative A 

would occur on soils that have severe limitations, total avoidance of these areas would not be feasible, 

especially given the increased surface disturbance under this alternative. Adherence to the Rawlins RMP 

and required COAs and BMPs (Appendix C) would ensure that disturbed areas are adequately stabilized 

to reduce soil erosion, surface runoff, and associated impacts to water quality and would minimize the 

reduction of soil productivity. Annual monitoring and adaptation of reclamation practices would be used 

to establish a trajectory to successful reclamation. 

4.3.3.3 Alternative B: Enhanced Resource Protection 

Adverse soil impacts under Alternative B would be similar to the Proposed Action but the extent and the 

degree of the impacts would be less because the amount of surface disturbance would be less. The 

construction of 8,950 natural gas wells using a combination of vertical and directional drilling techniques, 

together with associated access roads and related facilities, under the terms of Alternative B would 

produce initial (short-term) soil disturbance estimated at 45,516 acres, 3.6 percent less than the Proposed 

Action. This disturbance would comprise 4.3 percent of the total project area. Combined with the historic 

disturbance of 60,176 acres, almost 10 percent of the surface of the CD-C project area would be affected. 

The initial project disturbance is considered temporary, as successful interim reclamation is expected to 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—SOILS 

reduce the average drill-pad size (including access road) to approximately 40 percent of the short-term 

disturbance area. Reclamation of pipeline right-of-way disturbances would be initiated immediately upon 

completion of construction. Therefore, during the life of the project (45 to 55 years), the long-term 

disturbance area is expected to decrease to 18,249 acres, or 1.7 percent of the total project area. While the 

same number of wells is proposed for both the Proposed Action and Alternative B, the total disturbance 

area would be 1,684 acres (3.6 percent) less for Alternative B. Alternative B would disturb less area than 

the Proposed Action since more directional wells would be drilled—an estimated 438 more—resulting in 

less disturbance per well. 

The distribution of soil limitations for the 8,950 wells included under Alternative B, assuming that future 

drilling would occur at the same spatial distribution as current wells drilled, is projected to follow the 

distribution of wells in each rating class as provided in Table 4.3-1. For the 45,516 acres of initial 

disturbance for Alternative B, this translates to 33,118 acres with a slight risk for water erosion, 35,348 

acres with a moderate risk for wind erosion, 16,176 acres with a moderate runoff potential, 29,040 acres 

with a moderate limitation to road construction, and 26,128 acres with a poor reclamation potential 

(Table 4.3-1). 

Although the extent of areas with soil limitations makes it likely that implementation of Alternative B 

would occur on soils that have severe limitations, total avoidance of these areas would not be feasible, 

although the risk of adverse impacts would be reduced slightly because of the slightly reduced 

disturbance (3.6 percent). Adherence to the Rawlins RMP and required Conditions of Approval and Best 

Management Practices (Appendix C) would ensure that disturbed areas are adequately stabilized to 

reduce soil erosion, surface runoff, and potential impacts to water quality and would minimize the 

reduction of soil productivity. Annual monitoring and adaptation of reclamation practices would be used 

to establish a trajectory to successful reclamation. 

4.3.3.4 Alternative C: Cap on Surface Disturbance for High and Low Density Development 

Areas 

Adverse soil impacts under Alternative C would be similar to the Proposed Action but the extent and the 

degree of the impacts would be less because the amount of surface disturbance would be less. The 

construction of 8,950 natural gas wells using a combination of vertical and directional drilling techniques 

under the terms of Alternative C, together with associated access roads and related facilities, would 

produce initial (short-term) soil disturbance estimated at 42,955 acres, 9.0 percent less than the Proposed 

Action. This disturbance would comprise 4.0 percent of the total project area. Combined with the historic 

disturbance of 60,176 acres, almost 10 percent of the surface of the CD-C project area would be affected. 

The initial CD-C project disturbance is considered temporary, as successful interim reclamation is 

expected to reduce the average drill-pad size (including access road) to approximately 40 percent of the 

initial disturbance area. Reclamation of pipeline right-of-way disturbances would be initiated 

immediately upon completion of construction. Therefore, during the life of the project (45 to 55 years), 

the long-term disturbance area is expected to decrease to 17,318 acres, or 1.6 percent of the total project 

area. While the same number of wells is proposed for both the Proposed Action and Alternative C, the 

total disturbance area would be 4,245 acres (9 percent) less for Alternative C. Alternative C would have 

less total disturbance than the Proposed Alternative since additional directional wells would be drilled— 

an estimated 1,103 more—resulting in less disturbance per well. 

The distribution of soil limitations for the 8,950 wells included under Alternative C, assuming that future 

drilling would result in the same spatial distribution as current wells in the project area, is projected to 

follow the distribution of wells in each rating class as provided in Table 4.3-1. For the 42,955 acres of 

initial disturbance for Alternative C, this translates to 31,254 acres with a slight risk for water erosion, 

33,359 acres with a moderate risk for wind erosion, 15,266 acres with a moderate runoff potential, 27,406 

acres with a moderate limitation to road construction, and 24,658 acres with a poor reclamation potential 

(Table 4.3-1). 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—SOILS 

Although the extent of areas with soil limitations makes it likely that implementation of Alternative C 

would occur on soils that have severe limitations, total avoidance of these areas would not be feasible. 

However, the risk of adverse impacts would be reduced because of the reduced disturbance under this 

alternative (9.0 percent). Adherence to the Rawlins RMP and required COAs and BMPs (Appendix C) 

would ensure that disturbed areas are adequately stabilized to reduce soil erosion, surface runoff, and 

associated impacts to water quality and would minimize the reduction of soil productivity. Annual 

monitoring and adaptation of reclamation practices would be used to establish a trajectory to successful 

reclamation. 

4.3.3.5 Alternative D: Directional Drilling 

Adverse soil impacts under Alternative D would be similar to the Proposed Action but the extent and the 

degree of the impacts would be less because the amount of surface disturbance would be less. The 

construction of 8,950 natural gas wells using a combination of vertical and directional drilling techniques 

under the terms of Alternative D, together with associated access roads and related facilities, would 

produce initial (short-term) soil disturbance estimated at 36,449 acres, 22.8 percent less than the Proposed 

Action. This disturbance would comprise 3.4 percent of the total project area. Combined with the historic 

disturbance of 60,176 acres, 9 percent of the surface of the CD-C project area would be affected. The 

initial CD-C project disturbance is considered temporary, as successful interim reclamation is expected to 

reduce the average drill-pad size (including access road) to approximately 40 percent of the initial 

disturbance area. Reclamation of pipeline right-of-way disturbances would be initiated immediately upon 

completion of construction. Therefore, during the life of the project (45 to 55 years), the long-term 

disturbance area is expected to decrease to 14,952 acres, or 1.4 percent of the total project area. While the 

same number of wells is proposed for both the Proposed Action and Alternative D, the total disturbance 

area would be 10,751 acres (22.8 percent) less for Alternative D. Alternative D would have less total 

disturbance than the Proposed Alternative since additional directional wells would be drilled—an 

estimated 2,793 more—resulting in less disturbance per well. 

The distribution of potential soil limitations for the 8,950 wells included under Alternative D, assuming 

that future drilling would result in the same spatial distribution as current wells in the project area, is 

projected to follow the distribution of wells in each rating class as provided in Table 4.3-1. For the 

36,449 acres of initial disturbance for Alternative D, this translates to 26,520 acres with a slight risk for 

water erosion, 28,306 acres with a moderate risk for wind erosion, 12,954 acres with a moderate runoff 

potential, 23,255 acres with a moderate limitation to road construction, and 20,923 acres with a poor 

reclamation potential (Table 4.3-1). 

Although the extent of areas with soil limitations makes it likely that implementation of Alternative D 

would occur on soils that have severe limitations, total avoidance of these areas would not be feasible. 

However, the risk of adverse impacts would be reduced because of the reduced disturbance under this 

alternative (22.8 percent less). Adherence to the Rawlins RMP and required COAs and BMPs (Appendix 

C) would ensure that disturbed areas are adequately stabilized to reduce soil erosion, surface runoff, and 

associated impacts to water quality, and would minimize the reduction of soil productivity. Annual 

monitoring and adaptation of reclamation practices would be used to establish a trajectory to successful 

reclamation. 

4.3.3.6 Alternative E: No Action 

Under the No Action Alternative, it is assumed that no new natural gas drilling would occur. Adverse soil 

impacts would be limited to those related to historical disturbance in the project area. The No Action 

Alternative assumes that previously authorized activities would continue but that no new programmatic 

development would occur under this proposal. Historic development has resulted in the disturbance of 

60,176 acres, about 5.6 percent of the surface of the CD-C project area. This disturbance level would not 

increase under the No Action Alternative. The historic disturbance is considered temporary, because it is 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—SOILS 

assumed that successful interim reclamation would reduce the average unvegetated disturbance to 

approximately 30 percent of the initial disturbance area. Therefore, the long-term historic disturbance area 

is expected to decrease to 17,663 acres, or 1.7 percent of the total project area. 

For the No Action Alternative, no new impact to the soil resource would occur. Soil impact would be 

greatly reduced since no new disturbance would occur under this alternative (47,200 acres less than the 

Proposed Action). 

4.3.3.7 Impacts Summary 

For the Proposed Action, the total area of disturbance is estimated to be 47,200 acres, which would 

comprise approximately 4.4 percent of the project area. For Alternative A, the total area of disturbance is 

estimated to be 61,696 acres, which would comprise approximately 5.8 percent of the project area; 

Alternative A would result in a 30.7 percent increase over the disturbance anticipated for the Proposed 

Action. Alternative B would have a total disturbance area of 45,516 acres, which would comprise 4.3 

percent of the project area; Alternative B would result in a 3.6percent decrease from the disturbance 

anticipated for the Proposed Action. Alternative C would have a total disturbance of 42,955 acres, which 

consists of 4.0 percent of the project area; Alternative C would result in a 9percent decrease from the 

disturbance anticipated for the Proposed Action. Alternative D would have a total disturbance of 36,449 

acres, which consists of 3.4 percent of the project area; Alternative D would result in a 22.8percent 

decrease from the disturbance anticipated for the Proposed Action. Finally, for Alternative E, the No 

Action Alternative, no new surface disturbance would occur. 

Full and successful implementation of the required mitigation measures and BMPs would ensure that 

none of the three significance criteria would be exceeded. Soil productivity would not be reduced such 

that pre-disturbance conditions could not be recovered, the reclamation trajectory would be toward 

success, and disturbed areas would be adequately stabilized. Failure to successfully implement the 

required measures could result in significant impacts. 

4.3.3.8 Unavoidable Adverse Impacts and Additional Mitigation Measures 

The Proposed Action and alternatives would result in adverse soil impacts including the removal of 

vegetation and soil resulting in exposure to erosion, soil compaction, and undesirable mixing of 

subsurface soil horizons with potential saline/sodic soil conditions. However, full and successful 

implementation of the required mitigation measures as set forth in the Rawlins RMP and CD-C required 

Conditions of Approval and BMPs would ensure that none of the three significance criteria would be 

exceeded. 

No additional mitigation measures would be required. 

4.4 WATER RESOURCES 

4.4.1 Introduction 

Authorization of the proposed project would require full compliance with the Rawlins RMP, the Federal 

Clean Water Act (CWA), EO 11990 (wetlands protection), and EO 11988 (floodplain protection). These 

regulations require that certain permits/authorizations be obtained from the State of Wyoming (WDEQWQD and WOGCC) and the BLM and other federal agencies. Permits are required from WDEQ-WQD or 

WOGCC for disposal of produced water. State and federal approval is required for Applications for 

Permit to Drill (APDs); Federal Lease Obligations; development of surface runoff, erosion, and sediment 

control plans; injection-well permitting; oil-spill containment and contingency plans; Stormwater 

Pollution Prevention Plans; Spill Prevention Control and Countermeasures Plans; and CWA Section 404 

permits. 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—WATER RESOURCES 

For the purposes of this analysis, the evaluation of the Proposed Action and alternatives assumes 

adherence to these plans, permits, leases, and regulations for the protection of water resources. Many 

impacts associated with natural gas development are common to all alternatives and therefore are 

analyzed for general impacts in Section 4.4.3. The magnitude of impacts varies by alternative, so the 

magnitude of impacts is discussed as they relate to each alternative. 

Up to 500 of the 8,950 proposed wells could be coalbed natural gas (CBNG) wells. The volume of water 

produced in CBNG development is much greater than for conventional natural gas production. During 

initial coal-seam depressurization, CBNG wells can produce from 500–1,000 bbls/day of produced water 

compared to the average of 18 bbls/day for a conventional well. The actual volumes produced and the 

methods by which the produced water would be managed are greatly dependent on the site-specific 

development proposals. For that reason, this document does not contain any description of producedwater disposal for CBNG development and does not analyze the impacts of such development. Should the 

BLM receive site-specific CBNG proposals in the project area, the proposals, including the treatment of 

produced water, will be analyzed in a separate NEPA document at that time. 

4.4.2 Assumptions for Analysis 

Under all alternatives, the following would be adhered to: Operator-committed measures, required BMPs, 

including BMPs for Non-Point Source Pollution as applicable, as well as the regulations and plans 

described in Section 4.4.1. Per NEPA guidance, this analysis will be based on the premise that standard 

operating procedures including these BMPs and regulations would be followed under each alternative. 

Appendix C includes a summary description of the BMPs and APD Conditions of Approval typically 

used by the BLM in the Rawlins Field Office to implement the federal laws, regulations and policy aimed 

at mitigating environmental impacts. 

4.4.2.1 Surface Water Analysis Assumptions 

The analysis for surface water is based on the following specific assumptions: 

	 Disturbance to soil and vegetation, including compaction of soil, would increase water runoff and 

downstream sediment loads and lower soil productivity, thereby degrading water quality, channel 

structure, and overall watershed health. 

	 The degree of impact attributed to any one disturbance or series of disturbances is influenced by
 

several factors including location within the watershed, time and degree of disturbance, existing 

vegetation, soil characteristics, type of disturbance, and precipitation.
 

 Increased pollutants in surface waters would degrade habitat used by aquatic life and would affect 

other uses (e.g., stock-watering, irrigation, and drinking-water supplies). 

 The BLM would continue to develop and maintain water sources in upland areas to reduce impacts 

on wetland/riparian areas and provide a resource for livestock grazing. 

	 Access roads would follow standard construction practices. However, even properly designed roads 

would still alter hillslope hydrology and concentrate overland flow, increasing erosion in some 

areas. In areas with steep topography, roads are expected to be longer, resulting in greater impacts to 

surface-water resources. 

	 Fine-textured soils are more susceptible to water erosion and compaction when wet than mediumor coarse-textured soils; coarse-textured soils are more susceptible to wind erosion. 

4.4.2.2 Groundwater Analysis Assumptions 

Groundwater would be affected during construction of wells or by other subsurface project-development 

activities. The most likely pathway for groundwater contamination would be undetected spills and 

leachate from leaking produced-water facilities or mud pits. Additionally, undetected defects in either 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—WATER RESOURCES 

casing installation or cementing would be the most likely scenario for groundwater contamination to 

occur from actual gas well drilling and completion activities. Leakage from freshwater storage pits (used 

in fracturing operations) or other storage pits needed for well completion has the potential to leach salts 

from soils and impact shallow groundwater. Chemicals used for production drilling could cause local 

contamination of soils and groundwater if not managed properly. By design, the BLM approves APDs 

and associated drilling plans to protect potentially potable/usable groundwater intervals. Construction of 

well pads, proper disposal practices, proper well casing and cementing, and recycling of drilling fluids 

would be in accordance with BLM guidelines and should minimize adverse effects on groundwater 

quality. Withdrawal of produced water during production activities would impact target aquifers as would 

injection of the produced water. 

4.4.3 Management Objectives and Impact Significance Criteria 

The Rawlins RMP (BLM 2008a) prescribes the following management objectives associated with water 

resources (cited appendices are in the Rawlins RMP ROD, BLM 2008b): 

	 Maintain or improve water quality by managing surface land use and groundwater resources, where 

practical and within the scope of the BLM’s authority, according to the State of Wyoming Water 

Quality Rules and Regulations (Appendix 11). 

	 Maintain the hydrologic and water-quality conditions needed to support riparian/wetland areas; 

minimize flood and sediment damage to water resources from human and natural causes; analyze 

and, where possible, minimize levels of salt-loading in watersheds; and protect water resources used 

by the public (including impoundments, reservoirs, pipelines, and irrigation ditches) and by federal, 

state, and local agencies for fisheries, wildlife, wild horses, livestock, agricultural, recreational, 

municipal, and industrial uses. 

 Address all accidental spills of environmental pollutants on federal lands according to Appendix 32. 

 Implement intensive management of surface-disturbing activities (Appendix 13) in watersheds 

contributing to water bodies listed on the Wyoming 303(d) list of water bodies with water-quality 

impairments or threats, within the BLM’s authority. 

 Maintain or improve wetland/riparian areas as required by the Wyoming Standards for Healthy 

Rangelands (BLM 1997).
 

 Avoid playas when locating infrastructure due to poor soils and potential flooding.
 

 Ensure that activities that would cause water depletion within the Colorado River system or the 

North Platte River system comply with existing agreements, decrees, rules, and regulations 

(Appendix 11). 

Significance criteria are developed to gauge the magnitude of an impact on the human and natural 

environment. An impact on water resources as a result of project actions would be considered significant 

if its magnitude is such that mitigation measures discussed in Appendix C are insufficient and additional 

mitigation measures are warranted or if it were to persist indefinitely. 

4.4.3.1 Surface-Water Significance Criteria 

Impacts to surface water supplies would be considered significant if any of the following were to occur: 

1.	 Degradation of water quality beyond the designated use of the receiving water body, or other 

violations of federal or state water-quality standards, or negatively impacting a water body listed on 

the State 303(d) list of Impaired or Threatened Waterbodies. 

2.	 Project activities that elevate salt-loading to the Colorado River system above background 

conditions. 

3.	 Unmitigated loss of wetlands or wetland function (EO 11990 and 11988). 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—WATER RESOURCES 

4.	 Project-related activities that degrade wetland/riparian areas such that, as a minimum physical state, 

Standards for Healthy Rangelands (BLM 1997) are not being maintained. 

5.	 Streamflow characteristics of intermittent drainages or perennial streams are altered such that 

established uses are affected. 

6.	 Alteration of stream-channel geometry or gradient by accelerated runoff and erosion (e.g., 

undesirable aggradation, degradation, or side-cutting) beyond what would be expected by natural 

processes. 

7.	 Contamination of surface water from spilled fracking fluids, drilling fluids, and produced water. 

8.	 Soil loss greater than 2 tons per acre per year in areas attributed to surface disturbance. 

4.4.3.2 Groundwater Significance Criteria 

Impacts to groundwater resources or springs caused by project activities would be considered significant 

if any of the following were to occur: 

1.	 Interruption of the natural flow or level of groundwater to existing local springs, seeps, or flowing 

artesian wells, regardless of use or non-use. 

2.	 Degradation of groundwater quality in any aquifer such that it can no longer meet its classified 

current use(s). This includes impacts to underground sources of drinking water (USDW) or sole 

source aquifers (SSAs).
 

3.	 Spills or releases of fuels, liquids, chemicals, or hazardous materials (including but not limited to 

fracking fluids, drilling fluids, and produced water) that affect the quality of groundwater. 

4.4.4 Direct and Indirect Impacts 

The following impact discussions consider whether project impacts will result in the exceedance of one or 

more of the water resources significance criteria detailed above. The potential for an impact meeting or 

exceeding one or more of the significance criteria listed above is based on legal requirements (i.e., 

government regulatory standards), public perception, available scientific and environmental 

documentation, and professional judgment of resource specialists, as specified in 40 CFR 1508.27. The 

evaluation assumes successful implementation of BMPs and COAs. 

4.4.4.1 Impacts Common to the Proposed Action and All Alternatives 

The project area encompasses approximately 1.1 million acres. Existing development in the project area 

has resulted in 56,647 acres of surface disturbance, of which 13,706 acres remain unvegetated (Table 4.0-

1). The project area contains several active gas fields. To date, over 4,800 wells have been drilled in the 

project area; about 3,000 are still active producing natural-gas wells with accompanying productionrelated facilities, roads, and pipelines. Impacts to Muddy Creek have already occurred and two portions of 

Muddy Creek are now listed on the State 303(d) list of Impaired or Threatened Waterbodies due to habitat 

degradation (WDEQ 2012). According to WDEQ, the impairment to the middle portion of Muddy Creek 

is primarily due to livestock grazing, exacerbated by accelerated erosion associated with oil and gas 

activities (WDEQ 2010). The impairment to the lower portion of Muddy Creek is primarily due to 

exceedances of the chloride and selenium criteria (WDEQ 2012). Watershed restoration projects in the 

Muddy Creek sub-basin have also been implemented through the Grizzly Wildlife Habitat Management 

Area (WHMA), which includes the upper Littlefield Creek drainage and other portions of the upper 

Muddy Creek drainage (BLM 2008a). Under all action alternatives, revised and newly implemented 

BMPs and COAs, as outlined in Appendix C, would be attached to individual APDs. Given that there 

could be up to 30 companies operating within the project area, each with a unique approach to 

environmental protection measures, implementation of the BMPs and COAs will not be uniform. 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—WATER RESOURCES 

Variability in approaches will lead to differences in the level of environmental protection afforded. While 

these BMPs and COAs would not completely eliminate the potential for significant impacts, they would 

become the basis for enhanced environmental protection and offer a level of safeguard throughout the 

project area not present in earlier phases of development. Per NEPA guidance, this analysis is based on 

the premise that standard operating procedures including these BMPs, COAs, and regulations would be 

followed under each alternative and by each individual operator. 

Since specific locations for well sites or areas of concentrated development have not been identified in the 

Proposed Action or alternatives, this analysis will consider general project impacts. The Proposed Action 

and all action alternatives assume the construction of up to 8,950 wells and associated roads and pipelines 

over the course of 15 years. As discussed in Section 4.0.3, the well spacing would vary by area and 

includes: 40- to 60-acre spacing (12 to 16 wells per section), 80-acre spacing (eight wells per section), 

and 160-acre spacing (four wells per section) (Map 4.0-2). The areas of proposed dense (40- to 60-acre) 

well spacing are generally associated with active gas fields. Overall, approximately 60 percent of the 

project area may not undergo concentrated development (i.e. 40 to 60 or 80-acre well spacing). The extent 

of the unused (or less-used) portion of the project area would be defined by the suitability of production 

of natural gas and may or may not be continuous. Those areas without concentrated well locations would 

potentially experience surface disturbance from roads and pipelines to access wells and could also include 

areas of less-dense conventional well development. The Operators have indicated that they would vary 

well spacing when geology, permeability, and other conditions allow, but such areas have not yet been 

defined. 

Approximately 30 injection wells for produced-water disposal would be utilized for the project. Both 

injection and natural gas wells could share pads, although specific locations cannot be predicted. A very 

small percentage of the conventional well locations would be unsuccessful and would be plugged, 

abandoned, and reclaimed. 

Surface Water Impacts Common to All Alternatives 

The differing amounts of surface disturbance by alternative result from the varying number of well pads 

and the extent of required access roads and pipelines needed for resource development. The magnitude of 

impacts to surface water versus the acres of surface disturbance is not a one-to-one ratio. Roads and well 

pads will impact surface hydrology beyond their initial disturbance footprint. For the purposes of this 

impacts analysis, a change (increase or decrease) in the amount of surface disturbance generally translates 

to a corresponding change in the magnitude of impacts to surface water. 

The main impacts to surface-water resources from this project are brought about by contamination of 

surface water from the authorized discharge of hydrostatic test water and the accidental discharge (spill) 

of fracking fluids, drilling fluids, and produced water, and the impacts (including sediment loading) from 

surface disturbance related to project development/maintenance. 

Discharge/Spills. The authorized discharge of hydrostatic test water (water used to test the integrity of 

pipelines) and the accidental surface discharge of fracking fluids, drilling fluids, and produced water 

would impact nearby surface-water quality by degrading water quality (related to Criteria 1 and 7), which 

could in turn impact wetlands (related to Criteria 3 and 4) and increase salinity levels (related to Criterion 

2). There would be no authorized surface discharge of produced water as a result of the action 

alternatives. The magnitude of any impact would depend on the quality and quantity of the hydrostatic 

test water and any fluids accidentally discharged and the distance of the discharge/spill from a regulated 

water body (e.g. wetland, riparian area, and ephemeral, intermittent, or perennial stream). The following 

considers whether project impacts will result in the exceedance of water resources significance criteria 

based on discharge/spill impacts. 

Use or discharge of hydrostatic test water would be accomplished in a manner that should not affect soils, 

stream channels, surface water, and groundwater quality. After testing operations are completed, the 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—WATER RESOURCES 

water would be pumped into water-hauling trucks and transported to drilling locations within the project 

area to be used in conjunction with drilling operations or reused for other aspects of the construction 

and/or production process. However, if such water is not reused it must be disposed of in such a manner 

that soil-scouring and water-quality impairment would not result. Hydrostatic test water would be 

evaluated for compliance with state water-quality standards and no test water would be discharged unless 

such water meets these standards. Test water not utilized for drilling operations that meets water-quality 

standards would be disposed of onto undisturbed land having vegetative cover or into an established 

drainage channel in a manner that would not cause erosion (appropriate erosion control measures would 

be utilized). Furthermore, use and disposal of hydrostatic test water would comply with the mandatory 

right-of-way stipulation for hydrostatic testing, as well as the CWA required plan of development and the 

Wyoming Pollutant Discharge Elimination System (WYPDES) permit that would be required for the 

proposed project. The quantity of test water discharged would be dependent on the length of the pipelines 

needed for the handling of produced water (the longer the pipeline segment the more water is needed for 

testing). 

Spills of oil from production facilities would be controlled with the site-specific implementation of Spill 

Prevention Control and Countermeasures (SPCC) Plans, which would be developed by the Operators in 

accordance with 40 CFR Part 112. Each Operator would maintain a complete copy of the SPCC plan at 

the facility or at the nearest field office and have the plan available to the Regional Administrator for 

onsite review. BLM Notice NTL-3A requires the reporting of spills, accidents, blowouts, or other 

undesirable events that occur from federal minerals or on BLM-managed surface and IM WY-2009-21 

provides guidance and standards for spills and cleanup criteria for on-lease spills; otherwise, spills of 

hydrocarbon and hazardous materials meeting the requirements outlined in Section 4 of Chapter 4 of 

WDEQ Wyoming Water Quality Rules and Regulations would be reported to WDEQ-WQD. 

Surface Disturbance/Sediment Loading. Project development could result in up to approximately 

61,700 acres (Alternative A) of new surface disturbance related to road, pipeline, well pad, and facilities 

construction. These activities would result in a loss of vegetation and subsequent increased soil-surface 

exposure (related to Criteria 2, 3, 4, 5, 6, and 8); mixing of soil horizons (related to Criteria 2 and 8); soil 

compaction resulting in decreased infiltration capacity (related to Criteria 5, 6, and 8); loss of topsoil 

productivity (related to Criteria 5, 6, and 8); an increased susceptibility of the soil to water erosion 

(related to Criteria 2, 5, and 6); and off-site sedimentation that would cause channel instability and 

degradation of surface-water quality (related to Criteria 1, 2, 5, and 6). The magnitude of any impact 

would depend on the amount and type of disturbance and will be discussed by alternative. 

Matherne (2006) noted increased sediment production from well pad locations and confirmed that roads 

and well pads can provide conditions for focusing runoff and locally increasing erosion. Based on field 

observations, Matherne found that roads on sideslopes facilitate the erosional process in three ways: (1) 

they cut across and collect runoff from previously established drainages; (2) where they are cut into 

hillsides or into the land surface, roads provide focal points for the initiation of erosion; and (3) they 

provide conduits for sediment transport. Once mobilized, a portion of this sediment (resulting from these 

erosional processes) would move into channels in pulses that occur in relation to storm events. Some of 

this sediment would be temporarily stored in drainage bottoms and on hillslopes and a portion would be 

stabilized by vegetation and not travel to nearby drainages. Soil loss to water erosion is discussed in detail 

in Section 3.3.2.1. 

As described in Section 3.3 Soils, the project area contains many soils that are saline or sodic. These 

soils, when eroded as a result of surface disturbance, will make salt available to surface waters. Table 

3.3-1 summarizes the soil limitations within the project area for the following five categories: water 

erosion, wind erosion, runoff potential, road construction, and reclamation potential. Overall the risk of 

water erosion is slight (69.9 percent of the total project area has a slight water erosion potential). Only 4.3 

percent of the project area contains soils rated as having severe water-erosion potential. Soil 

characteristics such as depth, permeability, runoff rate, water capacity, and susceptibility to erosion vary 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—WATER RESOURCES 

widely. The diversity of soil parameters would require a broad spectrum of reclamation techniques. In 

addition, low annual precipitation and wind and water erosion would make successful reclamation in the 

project area difficult to attain. Therefore, the overall potential for successful reclamation is poor to fair. 

Revegetation would likely be difficult in a large portion of the project area due to the high concentration 

of salts in the soils. Salt concentrations are exacerbated by surface-disturbing activities. Due to the 

scarcity of wetland/riparian sites in the project area, the probability of well pads, roads, pipelines, and 

ancillary facilities directly impacting these resources is low. Impacts to wetland/riparian sites would occur 

as a result of sediment transported down drainages but the extent of impacts to wetland/riparian sites 

would be influenced by the distance of the disturbance from the wetland/riparian sites and the success of 

mitigation and reclamation efforts. Revegetation may be challenging on the estimated 75 percent of the 

project area indicated as possessing fair or poor reclamation potential (84 percent of area with historic 

disturbance) (Table 3.3-1). Current technology exists to stabilize disturbances, minimize erosion, and 

increase reclamation success provided that construction, maintenance, and operation of well pads and 

associated disturbances are in accordance with planned mitigation measures and reclamation. The 

Rawlins RMP (BLM 2008a) specifies that a buffer of 500 feet be maintained around perennial waters, 

springs, wells, wetlands and a buffer of 100 feet be maintained around the inner gorge of ephemeral 

channels. Formal wetland delineations have not been confirmed by the USACE for the entire project area. 

Wetlands have been confirmed along Muddy Creek, which is a Waters of the U.S. A relevant Nationwide 

Permit as authorized by Section 404 of the CWA would be required from the U.S. Army Corps of 

Engineers (USACE) Wyoming Regulatory Office for any disturbance activities in wetlands or Waters of 

the U.S. Additional BMPs and COAs that would protect wetland/riparian sites are included in Appendix 

C. 

Reclamation Success and Surface Water Impacts. Successful reclamation does not necessarily return 

an area to its previous hydrologic function. For example, re-establishing 80 percent of pre-disturbance 

ground-cover in 5 years would be considered successful (BLM 2008b). Perennial forbs, brush, and trees 

generally are more effective at reducing rain splash and can provide structure on the soil surface that can 

reduce surface runoff energy, but are generally not required for reclamation. Anderson (1975), in a study 

of 23 watersheds, found that conversion of steep forest and brush-lands to a grassland increased sediment 

yields by five times. Although this is an extreme case, it points out that not all vegetation functions the 

same at reducing surface runoff. Where interim reclamation has been successful, sagebrush and other 

shrub reestablishment would occur within the project life; however, many areas would not return to predisturbance function until 30 to 50 years after final reclamation. 

Surface Water Use. One of the management objectives included in the Rawlins RMP (BLM 2008a) 

associated with water resources prescribes that activities that would cause water depletion within the 

Colorado River system or the North Platte River system comply with existing agreements, decrees, rules, 

and regulations (Appendix 11). No surface water would be utilized to satisfy water demand, as the water 

needed for drilling and completion activities would come from new and existing State Engineer’s Office 

(SEO)-approved local water wells. 

Summary. An estimated 60,176 acres of surface disturbance has already occurred within the project area, 

a majority prior to stringent regulatory oversight, which may have resulted in the exceedance of some of 

the surface-water significance criteria listed above. As such, surface water impacts from the proposed 

project could exacerbate the magnitude of existing deteriorated conditions. The magnitude of any project 

related impacts and the potential to meet or exceed the significance criteria would depend on the 

disturbance associated with each alternative and will be discussed by alternative. Successfully utilizing 

BMPs and COAs listed in Appendix C to stabilize disturbance, minimize erosion, and increase 

reclamation success would reduce the potential for adding to the magnitude of existing impacts. 

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Groundwater Impacts Common to All Alternatives 

All of the action alternatives would result in the same number of new wells drilled (8,950 natural gas and 

30 injection), with the difference being the number of well pads and the extent of required access roads 

and pipelines needed for resource development. Because the action alternatives adjust the number of well 

pads, the alternative with the lowest number of pads would minimize risk of contamination of the 

groundwater resource; a lower number of well pads would reduce the probability of a pad being near a 

water well or above a shallow aquifer, which could then be impacted by development activity. Also, 

fewer pads would require fewer roads; both factors would reduce the amount of groundwater use for 

construction and dust suppression. 

Groundwater impacts would occur during the removal of groundwater for drilling, extraction of natural 

gas, and dust abatement; from improper drilling operations, especially poor casing and cementing of the 

well bore; from accidental releases of fluids (spills) associated with drilling and fracking operations, 

produced water, and other hazardous liquids to soils and surface-water systems; and through subsurface 

disposal (injection) of produced water. 

Groundwater Removal. Impacts from groundwater removal are associated with impacts to groundwater 

quantity and the potential to impact springs and flowing wells. There are no significance criteria related to 

impacts to groundwater quantity from groundwater removal. Criterion 1 is related to impacts to springs, 

seeps and flowing wells from groundwater removal. 

In terms of subsurface impacts, the development in the proposed project area would consist of natural gas 

wells completed primarily in the Almond Formation, a member of the late Cretaceous Mesaverde Group. 

There is no current practical beneficial use for water in this stratum due to the high level of total dissolved 

solids (TDS), the presence of hydrocarbons, and the availability of higher quality water from shallower 

aquifers. Secondary natural gas reserves may also be encountered in other formations. There are 288 

existing non-energy related/non-industrial domestic, municipal, or stock wells within the project area or 1 

mile adjacent to it (SEO 2011). Only four of these wells are completed at depths that would include 

aquifers of the Mesaverde Group and, depending on their location respective to the deeper natural gas 

development, could be affected by groundwater withdrawals relating to conventional oil and gas 

production. Due to the low density of non-energy related water wells in the project area, impacts related 

to groundwater removal would not be considered significant. 

While the number of natural gas wells proposed remains the same, each alternative results in a different 

number of well pads. As such, there would be a slight difference between alternatives based on the 

quantity of water needed for road and well pad construction and dust suppression and this difference is 

reflected in the per-well range of water needed discussed below. Applying the expected per-well water 

volume of 24,000 to 42,000 bbls/well needed for drilling and completion and well pad and road 

construction and assuming 600 wells/year, the water demand for the proposed action and the action 

alternatives would be between 1,856 ac-ft (14.3 million bbls) and 3,248 ac-ft (25.1 million bbls) per year 

(based on information provided in Section 2.2.1.2 Drilling and Completion). The total water demand 

over the 15 years required for well drilling would be between 27,840 ac-ft (214.1 million bbls) and 48,720 

ac-ft (375.9 million bbls). This total amount of water needed for drilling and completion activities would 

come from new and existing SEO-approved local water wells. While estimates of available water in all 

aquifers beneath the project area are not available, using estimates of the volume of producible 

groundwater from Cleary et al. (2010), the volume of groundwater above 1,000 feet in the Tertiary age 

aquifers under the project area alone is approximately 9.67 million ac-ft. Therefore, the total for all water 

needed for well development and pad and road construction represents between 0.3 and 0.5 percent of the 

available water in the Tertiary age aquifers under the project area. As discussed in Section 3.4.3.1, 

available water is also found in Quaternary, Upper and Lower Cretaceous, and Jurassic age aquifers. Fisk 

(1967) estimated that the volume of moderately good-quality groundwater within the Great Divide 

Structural Basin was 500 million ac-ft and 300 million ac-ft within the Washakie Structural Basin. The 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—WATER RESOURCES 

combined annual recharge for the Great Divide and Washakie structural basins was estimated at 11,300 

ac-ft (Fisk 1967), which is well above the estimated annual 1,856 ac-ft to 3,248 ac-ft water demand for 

the CD-C project. 

Due to technological difficulties and regulatory constraints related to water quality, relatively little 

produced water can be beneficially used at this time (based on information provided by the Operators). 

Reuse of drilling mud is currently being employed and is reducing the water demands. As described in 

Section 3.4.3.2 Groundwater Use, there are presently 1,081 groundwater wells (including the 288 nonenergy related wells referenced above) permitted within 1 mile of the project area. The total water 

demand would not likely adversely affect the existing surface-water or groundwater rights in the project 

area, provided full coordination is implemented with the SEO and the BLM. The total water demand 

would not cause significant adverse impacts on the groundwater resources within the project area. 

The project area contains springs and flowing wells that are important local water sources for livestock, 

wildlife, and wild horses. The springs in the area occur south of I-80 in the Green River Formation and 

north of I-80 in the Wasatch and Battle Springs Formations (Mason and Miller 2005; Bartos et al. 2006). 

Impacts related to groundwater removal would not be considered significant for Criterion 1 resulting from 

the Proposed Action or any action alternatives, as the source aquifers are stratigraphically higher than the 

natural gas exploration targets. Groundwater withdrawals from water wells have the potential to interrupt 

flowing wells only if supply wells are completed in the same aquifer as the flowing well and close enough 

to this flowing well to cause interference. 

One of the management objectives associated with water resources that is included in the Rawlins RMP 

(BLM 2008a) prescribes that activities that would cause water depletion within the Colorado River 

system comply with existing agreements, decrees, rules, and regulations. Water needed for drilling and 

completion activities would come from new and existing State Engineer’s Office (SEO)-approved local 

water wells; most (96 percent) SEO-approved wells are completed in Tertiary age aquifers, particularly 

the Wasatch Formation. According to Mason and Miller (2005), the Wasatch Formation has the potential 

to lose groundwater to the southeast and ultimately to the Colorado River system. Roughly 20 percent of 

the Wasatch Formation within the CD-C project area is within that portion of the Washakie Structural 

Basin that loses groundwater to the southeast toward the Little Snake River, a tributary of the Colorado 

River. As such, an interruption of this groundwater flow could lead to depletions to the Colorado River 

system, although the proportion of flow in the Little Snake River that comes from groundwater discharge 

from the Wasatch Formation has not been quantified. The most important agreement affected by 

depletions in the project area is the Upper Colorado River Endangered Fish Recovery Program, a 

partnership working to recover the endangered fish of the Upper Colorado River Basin. Under the 

Recovery and Implementation Program (RIP) for Endangered Fish Species in the Upper Colorado River 

Basin, “any water depletions from tributary waters within the Colorado River drainage are considered as 

jeopardizing the continued existence of these fish.” Section 4.9.3.1 includes a brief description of the 

Upper Colorado River Endangered Fish Recovery Program and how depletion fees defined under the RIP 

are calculated. 

The magnitude of depletions is difficult to determine at this time since the specific locations of the drill 

pads and associated roads and pipelines are not known, but the estimated annual freshwater use within the 

CD-C project area would range from 1,856 to 3,248 ac-ft /yr and would average 2,552 ac-ft /yr. Assuming 

that CD-C project groundwater use from the Wasatch Formation is evenly distributed across the project 

area, approximately 20 percent of the groundwater would come from that portion of the Wasatch 

Formation that could contribute water to the Little Snake River. Therefore, an average of 510 ac-ft/yr of 

groundwater would be removed from the Wasatch Formation in this area. Fisk (1967) estimated that the 

Wasatch Formation within the Washakie Structural Basin holds some 300,000,000 ac-ft of groundwater 

in storage. In light of this volume of groundwater in storage, the 510 ac-ft/yr withdrawn from the Wasatch 

Formation within the Washakie Structural Basin would likely have no measurable effect on Colorado 

River Flows. If, however, it is determined that groundwater withdrawals result in a depletion in the 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—WATER RESOURCES 

Colorado River, an agreement would be reached prior to operation between the BLM and the USFWS as 

to how much each Operator would contribute to the Upper Colorado River Endangered Fish Recovery 

Program for water depletions. 

Drilling Operations. Well-drilling, completion, and operation activities would impact groundwater 

resources (related to Criteria 2 and 3). Construction of well pads, disposal practices, well casing and 

cementing, and recycling of drilling fluids would be in accordance with BLM guidelines and should 

minimize the risk of degrading groundwater quality. 

Well-drilling and completion activities are not likely to impact existing groundwater quality if the project 

is in compliance with the BLM’s Onshore Oil and Gas Order No. 2. These guidelines specify the 

following: 

...proposed casing and cementing programs shall be conducted as approved to protect or 

isolate all usable water zones, potentially productive zones, lost-circulation zones, 

abnormally pressured zones, and any prospectively valuable deposits of minerals. Any 

isolating medium other than cement shall receive approval prior to use (BLM 1988). 

The BLM’s Onshore Oil and Gas Order No. 2 defines “usable water” as groundwater with TDS of 10,000 

parts per million or less encountered at any depth. This definition of useable water corresponds to the 

EPA’s definition of a USDW. To comply with the order, wells must be completed using state-of-the-art 

techniques, such as cementing and other proven technologies, such that usable water and unusable water 

do not mix. Assuming compliance with this order, no contamination of usable groundwater would likely 

occur. Well-drilling and completion as proposed in Chapter 2 Proposed Action and Alternatives 

complies with Onshore Order No. 2. However, improper drilling and completion techniques, especially 

poor casing and cementing of the well bore, would result in degradation of groundwater quality due to the 

potential release of drilling fluids and hydrocarbons and the mixing of variable-quality waters from 

different water-bearing strata that are pierced by the borehole. 

A central feature of the well completion process is hydraulic fracturing (fracking), which involves 

injecting fracturing fluids into the target formation at a force exceeding the parting pressure of the rock, 

thus inducing a network of fractures through which oil or natural gas can flow to the wellbore. The 

fractures are filled with sand or other porous materials which serve as proppants to facilitate recovery of 

natural gas. Hydraulic fracturing has been used for decades in the CD-C area. It is currently excluded 

from Underground Injection Control regulation under the Safe Drinking Water Act (SDWA) except when 

diesel fuel is used as a component of the fracking fluid. 

The EPA is currently conducting an industry-wide study that seeks to understand any relationships 

between hydraulic fracturing and drinking water. As part of that study, the EPA issued information 

requests to leading national and regional hydraulic fracturing service providers. The EPA is seeking 

information on the chemical composition of fluids used in the hydraulic fracturing process, data on the 

impacts of the chemicals on human health and the environment, standard operating procedures at 

hydraulic fracturing sites and the locations of sites where fracking has been conducted (EPA 2010a). No 

studies related to impacts from hydraulic fracturing have been conducted in the CD-C project area and no 

occurrences of drinking water contaminated by fracking have been recorded. 

Newly adopted WOGCC regulations require Operators to provide the Commission with the exact 

chemical content of their fracking fluid. While the information may be held as proprietary, the 

Commission will be able to provide WDEQ with the chemical composition of the fracking fluid if there is 

ever a question of aquifer contamination. The BLM has issued a proposed rule governing “Oil and Gas; 

Well Stimulation, Including Hydraulic Fracturing, on Federal and Indian Lands.” As proposed, this rule 

would (1) provide disclosure to the public of chemicals used in hydraulic fracturing on public land and 

Indian land, (2) strengthen regulations related to well bore integrity, and (3) address issues related to 

flowback water (BLM 2012e). 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—WATER RESOURCES 

The BLM is also proposing a rule to ensure that fracturing operations conducted on the public mineral 

estate (including split estate where the federal government owns the subsurface mineral estate) follow 

certain best practices, including the public disclosure of chemicals used in hydraulic fracturing operations 

on federal lands, confirmation that wells used in fracturing operations meet appropriate construction 

standards, and a requirement that operators put in place appropriate plans for managing flowback waters 

from fracturing operations (Federal Register 2012b). 

It is expected that fracking effects would not extend beyond 500 feet from the well bore (EPA 2002). 

Accordingly, the potential for contamination of groundwater by the fracking fluids would be limited to 

this distance from each well over the production interval. Because fracking would be conducted at 

considerable depths (8,000 to 12,000 feet below ground surface), groundwater resources near the surface, 

such as springs, the shallow alluvium, and domestic wells would not be affected. 

Due to the use of state-of-the-art drilling and well-completion techniques, including techniques 

incorporated in the BLM’s Onshore Oil and Gas Order No. 2, and if BMPs and COAs related to drilling 

are implemented, impacts related to degradation of groundwater quality would not be considered 

significant for Criteria 1, 2 and 3. In addition, the likelihood of mixing, which could occur during the 

relatively short period of time during drilling, would be low and impacts would not be considered 

significant for Criterion 2. 

Spills. Reserve pits would be used to contain drilling fluids, cuttings, and wastewater produced from the 

well-drilling operations (related to Criterion 3). The reserve pits would be constructed with an 

impermeable liner to prevent seepage and possible contamination of surface and groundwater. Likewise, 

the storage of fresh water, either in lined pits, tanks, or storage pits would be in accordance with WOGCC 

rules on private and state mineral estate and with BLM’s IM WY-2012-007 on public minerals. Reserve 

and storage pits on federal mineral estate are evaluated and approved by the BLM through the APD, rightof-way grant, or Sundry Notice permitting processes. 

Spills could also occur from water and condensate gathering pipelines. State-of-the-art pipeline 

construction techniques, including hydrostatic pressure testing, would limit the impacts from the project 

and impacts from spills would not be considered significant for Criterion 3. 

Accidental spills of oil from production facilities would be addressed through implementation of SPCC 

Plans, which would be developed by the Operators in accordance with 40 CFR Part 112. Each Operator 

would maintain a complete copy of the SPCC plan at the facility or at the nearest company field office 

and have the plan available to the Regional Administrator for onsite review. BLM Notice NTL-3A 

requires the reporting of spills, accidents, blowouts, or other undesirable events that occur from federal 

minerals or on BLM-managed surface and IM WY-2009-21 provides guidance and standards for spills 

and cleanup criteria for on-lease spills; otherwise, spills of hydrocarbon and hazardous materials meeting 

the requirements outlined in Section 4 of Chapter 4 of WDEQ Wyoming Water Quality Rules and 

Regulations would be reported to WDEQ-WQD. 

If state-of-the-art pit construction techniques are used, if Hazardous Materials Emergency Response Plan 

and SPCC Plans are implemented, and with the implementation of BMPs and COAs related to handling 

of fluids, the likelihood of degradation of groundwater as a result of spills would be limited and the 

impacts would not be considered significant for Criterion 3. 

Subsurface Disposal. Groundwater aquifers would be affected during disposal of produced water from 

oil and gas activities (related to significance Criterion 2). Produced water would be transported by truck 

to approved water-disposal injection wells or evaporation ponds, or by pipeline to treatment facilities. A 

majority of the produced water would likely be injected with a smaller portion disposed of via water 

treatment facilities/surface evaporative pits (based on information provided by the Operators). Subsurface 

water disposal methods are administered by the EPA under the underground injection control (UIC) 

program (40 CFR 144). The UIC program ensures that injection wells meet appropriate performance 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—WATER RESOURCES 

criteria for protecting USDWs. There are five classes of injection wells permitted under the UIC program 

based on similarity in the fluids injected, activities, construction, injection depth, design, and operating 

techniques. Class II and Class V injection wells would likely be used to dispose of produced water 

resulting from the CD-C project. Class II injection well permits are issued by the WOGCC for injection 

of fluids associated with oil and conventional natural gas production by an individual operator (EPA 

2011a). Class V injection wells are permitted through WDEQ-WQD and cover wells not included in 

Classes I-IV. In general, Class V wells inject non-hazardous fluids into or above USDWs and are 

typically shallow, onsite disposal systems, such as septic systems and for disposal of CBM produced 

water. An average of 98 percent of produced water from natural gas wells in the vicinity of the project 

area is disposed of by injection, based on 2010 production and injection rates for wastewater from eight 

local gas production fields (WOGCC 2011a). 

During the period of full production for the Proposed Action and action alternatives, there would be 

approximately 7,600 ac-ft of water produced per year that would require disposal, based on an average of 

18 bbls/day/well for each of the 8,950 wells. Lesser amounts would be produced each year prior to and 

following the period of peak water production. Using the current 98 percent average rate of injection of 

produced water, approximately 7,500 ac-ft/year of the CD-C produced water would be injected during the 

height of the CD-C project under the action alternatives. 

The construction of an estimated 30 additional injection wells and 20 other water handling facilities is 

planned in order to dispose of produced water related to the action alternatives. The Operators have not 

identified the anticipated well class or reservoirs capable of taking injected water at the volumes needed 

by the production rates projected in the area. The minimum and maximum volumes currently permitted 

for injection into existing disposal wells in the area range between 1,000 bbls/day (47 ac-ft/year) and 

33,000 bbls/day (1,552 ac-ft/year) per well, respectively, depending on the hydraulic properties of the 

target aquifer (WOGCC 2011a). If all of the project-related produced water were to be injected, the 

average per-well volume of injected water for the 30 additional injection wells would need to be 

approximately 252 ac-ft /year (to achieve the approximate 7,500 ac-ft/year needed for well disposal). This 

is well within the range of permitted injection volumes of existing disposal wells. 

There are currently 22 permitted oil and gas related wastewater disposal facilities within 20 miles of the 

project area (not including subsurface disposal wells) (WDEQ 2011). A majority of these facilities utilize 

some variation on evaporation. Other forms of disposal include a variety of separation methods (reverse 

osmosis or ion exchange). It is expected that these facilities would continue to be utilized to the extent 

possible. Project plans include an estimated 20 additional produced water handling facilities. According 

to Boysen et al. (2002), individual facility evaporation rates of 30 gallons per minute (48 ac-ft/year) at 

wastewater disposal facilities utilizing misting towers are achievable. Given the proposed 20 additional 

wastewater disposal facilities, the capacity is more than adequate to dispose of produced wastewater that 

is not injected (100 ac-ft/year). 

If disposal wells are installed according to EPA and WDEQ requirements and if BMPs and COAs related 

to handling of fluids are implemented, the likelihood of degradation of groundwater as a result of water 

disposal would be limited and the impacts related to Criterion 3 would not be considered significant. 

Groundwater Impacts Summary. Impacts from groundwater removal are associated with impacts to 

groundwater quantity and the potential to impact springs and flowing wells. Groundwater removal by the 

project is expected to be well below the annual recharge of the structural basins underlying the project 

area. The likelihood of these withdrawals interrupting flowing wells is low. The 510 ac-ft/yr withdrawn 

from the Wasatch Formation within the Washakie Structural Basin would likely have no measurable 

effect on Colorado River flows. 

Drilling and completion would result in degradation of groundwater quality if drilling fluids, 

hydrocarbons, or variable-quality water from different strata are released into water-bearing strata that are 

pierced by the borehole. With use of state-of-the-art drilling and well-completion techniques, including 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—WATER RESOURCES 

proper casing and cementing of the well bore, and implementation of drilling BMPs and COAs, impacts 

related to drilling of natural gas wells would not be considered significant for Criteria 1, 2, or 3. 

If state-of-the-art pit construction techniques are used, if Hazardous Materials Emergency Response Plan 

and SPCC Plans are implemented, and if BMPs and COAs related to handling of fluids are implemented, 

the likelihood of degradation of groundwater as a result of spills would be limited and the impacts would 

not be considered significant for Criterion 3. 

If disposal wells are installed according to EPA and WDEQ requirements and if BMPs and COAs related 

to handling of fluids are implemented, the likelihood of degradation of groundwater as a result of 

subsurface disposal of produced water disposal would be limited and the impacts related to Criterion 3 

would not be considered significant. 

4.4.4.2 Impacts Associated with the Proposed Action 

The types of impacts would be the same as those discussed in Section 4.4.4.1 Impacts Common to the 

Proposed Action and All Alternatives, but would vary in magnitude when compared to the other 

alternatives. Under the Proposed Action, 6,126 pads would be required for the 8,950 wells. Total 

construction-phase surface disturbance would be 47,200 acres (approximately 4.4 percent of the project 

area). With successful reclamation during the life of the project (45 to 55 years), total disturbances would 

be reduced to about 19,000 acres (about 1.8 percent of the project area). The construction disturbance 

would not be uniformly distributed across the project area, but rather, project facilities would be located 

where the efficiency and feasibility of extracting the natural gas would be the highest. As described 

earlier, most of the project area has fair/poor reclamation potential, which is considered difficult to 

reclaim. Where sagebrush, juniper, or other vegetation that is difficult to reestablish is disturbed, the 

location would not return to pre-disturbance hydrologic function until 30 to 50 years after the end of the 

project in some locations, as described in Section 4.4.4.1. 

Surface Water. As with all following action alternatives, the magnitude of the surface water impacts 

would be primarily related to the amount of sediment mobilization resulting from disturbance (the number 

and size of the drill pads, the distance and width of the roads, and the distance and width of the pipeline 

corridors). The quality and quantity of the hydrostatic test water discharged, the quality and quantity of 

any fluids accidentally discharged, and the distance of the discharge/spill from a water body or water 

course (e.g. wetland, riparian area, and ephemeral, intermittent, or perennial stream) would also be of 

concern. No test water would be discharged unless such water meets State water-quality standards. The 

quantity of test water discharged would be dependent on the length of the pipelines needed to manage 

produced water (volume related to pipe length) and the amount of test water not reused for other 

purposes. 

Impacts related to disturbance/sediment would be considered significant (depending on the amount of 

disturbance) for surface water Criteria 1, 2, 5, 6 and 8 as a result of the fair/poor reclamation potential for 

a majority of the project area. Impacts related to disturbance/sediment loading would not be considered 

significant for Criteria 3 and 4. 

Impacts related to the discharge/spill of water would not be considered significant for Criteria 1, 2, 3, 4, 

and 7. The State water quality standards regulating discharge of test water, the BMPs and COAs for 

construction and maintenance of pipelines and reserve pits, and the Hazardous Materials Management and 

Release Contingency Plans and SPCC Plans would minimize effects of spills. 

Groundwater. The magnitude of the groundwater impacts from the Proposed Action (and all following 

action alternatives) would be related to the number of wells and well pads proposed and the extent of 

required access roads and pipelines needed for resource development. Groundwater impacts would occur 

during the removal of groundwater (Criterion 1), from improper drilling operations, especially poor well 

casing and cementing practices (Criteria 1, 2, and 3), through subsurface disposal (injection) of produced 

water (Criterion 2), and from accidental releases of fluids [spills] (Criteria 2 and 3). 

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Impacts related to groundwater removal would not be considered significant for Criterion 1 since the 

source aquifers for the springs and seeps are stratigraphically higher than the natural gas exploration 

targets. 

Impacts related to improper drilling techniques would be not be considered significant for groundwater 

Criteria 1, 2 and 3 due to the use of state-of-the-art drilling and well-completion techniques included in 

the BLM’s Onshore Oil and Gas Order No. 2 and the implementation of drilling BMPs and COAs. 

4.4.4.3 Alternative A: 100-Percent Vertical Drilling 

The types of impacts for Alternative A would be the same as those described in Section 4.4.4.1, but the 

disturbance (initial and long-term) would increase when compared to the Proposed Action. This 

alternative assumes that no wells would be drilled using directional-drilling techniques. Under Alternative 

A, 8,950 pads would be required for the 8,950 wells. Total construction-phase surface disturbance would 

be 61,696 acres, 56,400 acres related to well pads and roads. This is 31 percent more than the Proposed 

Action. 

Surface Water. Impacts from both authorized and accidental surface discharge of fluids related to 

surface water Criteria 1, 2, 3, 4, and 7 would be greater than the Proposed Action. Considering the 

significant increase in the amount of surface disturbance, impacts would be considered significant related 

to discharge/spill of water, depending on the locations of the drill pads and associated roads and pipelines. 

Impacts related to disturbance/sediment loading would be considered significant for surface water Criteria 

1, 2, 4, 5, 6, and 8, primarily as a result of the significantly greater amount of surface disturbance. 

Groundwater. Under Alternative A, the per-well water use would be skewed toward the maximum of 

42,000 bbls/well due to the additional water needed for road and pad construction and dust abatement. 

Because produced water cannot be used for dust abatement and since this alternative has the greatest 

amount of surface disturbance, Alternative A would likely place the greatest demand on the aquifers 

targeted for water supplies. Because this alternative increases the number of well pads, the risk of 

contamination of the groundwater resource would increase due to the greater probability of a pad being 

near a water well or above a shallow aquifer, which, by proximity, raises the chance of contamination 

resulting from leaks, spills, or improper drilling techniques, especially poor well casing and cementing 

practices. 

The potential to meet or exceed groundwater Criterion 1 from impacts related to groundwater removal 

would be greater than the Proposed Action because of increased water demands for hydrostatic testing 

and dust suppression but the impacts would not be considered significant since the source aquifers for the 

springs or seeps are stratigraphically higher than the natural gas exploration targets and the areas in the 

vicinity of flowing wells can be avoided when and if new water supply wells are developed. Due to the 

amount of available groundwater in storage, groundwater removal resulting from Alternative A would not 

significantly impact groundwater quantities. Impacts from degradation of groundwater from disposal 

wells would not be considered significant for Criterion 2 since disposal wells would be installed 

according to EPA and WDEQ requirements and since BMPs and COAs related to handling of fluids 

would be implemented. State-of-the-art pit and pipeline construction techniques, including the use of pit 

liners and hydrostatic pressure testing, would protect the groundwater resource and the impacts from 

spills resulting from Alternative A would not be considered significant for Criterion 3. 

4.4.4.4 Alternative B: Enhanced Resource Protection 

The types of impacts for Alternative B would the same as those described in Section 4.4.4.1, but the 

short- and long-term disturbance would decrease when compared to the Proposed Action. Under 

Alternative B, 5,798 pads would be required for the drilling of 8,950 wells. Total construction-phase 

surface disturbance would be 45,516 acres, 4 percent less than the Proposed Action. This alternative 

identifies the resources that may be more at risk from natural gas development and the enhanced resource 

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protections that would be implemented for these resources, which include enhanced protections and 

mitigation. The alternative also recognizes that future development may be more intensive than currently 

expected or may have unintended consequences, resulting in impacts to wildlife habitats and populations 

in areas that were not anticipated or impacts that occur at a faster pace than anticipated. Under Alternative 

B, RMP development restrictions would be expanded near perennial waters, springs, wells, and wetlands 

from 500 feet to 0.25 mile and the avoidance distance within the Muddy Creek/Red Wash sensitive fish 

habitat area would be expanded to 0.5 mile. Water quality monitoring on upper Muddy Creek would be 

extended to lower Muddy Creek within the CD-C area, which has been designated a 305(b) threatened 

stream. Although this alternative describes protections and mitigations for specifically identified 

resources, the overall purpose of the alternative would be to maintain healthy ecosystem function at the 

landscape level over the entire project area. In so doing, the alternative thus strives to ensure that the 

Wyoming Standards for Healthy Rangelands will be satisfied, as well as State water quality state 

standards. 

Surface Water. Impacts to the surface-water resource would be less in magnitude than those for the 

Proposed Action due to the reduced amount of surface disturbance and the enhanced protection of the 

specific resources and habitats (particularly along Muddy Creek and its tributaries, where setback 

distances on federal minerals and surface would be increased from 500 feet to 0.25 mile or even 0.5 mile 

in some cases), which would reduce surface-water impacts. While this alternative does not significantly 

reduce the acres of disturbance compared to the Proposed Action and impacts would still occur, it does 

identify surface disturbance and population thresholds that, if exceeded, would signal the need for still 

more protections and mitigation and then outlines the additional measures that may be required. 

Impacts from both authorized and accidental surface discharge of fluids related to surface water Criteria 

1, 2, 3, 4, and 7 would be less than the Proposed Action. Impacts related to the discharge/spill of water 

would not be considered significant considering the decrease in the amount of surface disturbance and the 

increased buffers around surface-water features. 

Impacts related to the disturbance/sediment loading would be considered significant for Criterion 6, 

depending on the locations of the drill pads and associated roads and pipelines. Impacts related to 

disturbance/sediment loading would not be considered significant for Criteria 1, 2, 3, 4, 5, 6, and 8. Even 

though this alternative is directed primarily at habitat protection, it would reduce the potential for creating 

impacts that exceed surface-water Criteria 2 and 8 compared to the Proposed Action, given the reduced 

number of well pads, reduced surface disturbance, and increased setback distances from specified high 

value water resources. 

Groundwater. Because this alternative reduces the number of well pads, the risk of contamination of the 

groundwater resource would decrease compared to the Proposed Action due to the decreased probability 

of a pad being near a water well or above a shallow aquifer, which, by proximity, lowers the chance of 

contamination resulting from leaks, spills, or improper drilling techniques, especially poor well casing 

and cementing practices. 

Impacts related to groundwater removal would not be considered significant for Criterion 1 since the 

source aquifers for the springs and seeps are stratigraphically higher than the natural gas exploration 

targets and the areas in the vicinity of flowing wells can be avoided when and if new water supply wells 

are developed. Due to the amount of available groundwater in storage, groundwater removal resulting 

from Alternative B would not significantly impact groundwater quantities. Impacts related to improper 

drilling techniques would not be considered significant for Criteria 1, 2 and 3 due to the use of state-ofthe-art drilling and well-completion techniques included in the BLM’s Onshore Oil and Gas Order No. 2 

and the BMPs and COAs related to drilling that would be implemented. Disposal wells are installed 

according to EPA and WDEQ requirements and BMPs and COAs related to handling of fluids would be 

implemented so the likelihood of degradation of groundwater as a result of water disposal would be 

limited and impacts would not be considered significant for Criterion 2. State-of-the-art pit and pipeline 

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construction techniques, including the use of pit liners and hydrostatic pressure testing, would protect the 

groundwater resource and the impacts from spills resulting from Alternative B would not be considered 

significant for Criteria 2 and 3. 

4.4.4.5 Alternative C: Surface Disturbance Cap—60 Acres and 30 Acres per Section 

The types of impacts for Alternative C would be the same as those described in Section 4.4.4.1, but 

would be reduced in magnitude when compared to the Proposed Action because of the decrease in 

disturbance (initial and long-term). Under Alternative C, 5,299 pads would be required for the drilling of 

8,950 wells. Total construction-phase surface disturbance would be 42,955 acres, 9 percent less than the 

Proposed Action. This alternative designates parts of the project area as “high-density” areas—those areas 

that have undergone the greatest natural gas development to date. Within the high-density areas, a 60-acre 

cap would be placed on the amount of unreclaimed surface disturbance at any one time per section of 

public land. For the remainder of the project area—the low-density areas—the disturbance cap would be 

30 acres per section. All prior surface disturbances related to long-term use for roads or on-pad 

production facilities and all disturbances that had not been successfully reclaimed would count against the 

cap. Acreage that had successfully undergone interim reclamation would not count against the cap. The 

aim of this alternative is to encourage better reclamation and reduced surface disturbance, primarily 

through increased directional drilling. 

Surface Water. Impacts to surface water from Alternative C would be less in magnitude than those for 

the Proposed Action due to the capping of disturbance within a 640-acre section of public land. The 

disturbance cap in place under this alternative would be closely related to the density of existing 

disturbance and the amount of existing reclamation in the project area and would incentivize successful 

reclamation. 

Impacts related to the discharge/spill of water would not be considered significant for Criteria 1, 2, 3, 4, 

and 7 considering the decrease in the amount of surface disturbance. 

Impacts related to disturbance/sediment loading would be considered significant for Criteria 2 and 6. 

Impacts related to the disturbance/sediment loading would not be considered significant for Criteria 1, 3, 

4, 5, and 8. This is primarily due to the large reduction in surface disturbance compared to the Proposed 

Action. 

Groundwater. Because this alternative reduces the number of well pads, the risk of contamination of the 

groundwater resource would decrease compared to the Proposed Action due to the decreased probability 

of a pad being near a water well or above a shallow aquifer, which, by proximity, lowers the chance of 

contamination resulting from leaks, spills, or improper drilling techniques, especially poor well casing 

and cementing practices. 

Impacts related to groundwater removal would not be considered significant for Criterion 1 since the 

source aquifers for the springs and seeps are stratigraphically higher than the natural gas exploration 

targets and the areas in the vicinity of flowing wells can be avoided when and if new water supply wells 

are developed. Due to the amount of available groundwater in storage, groundwater removal resulting 

from Alternative C would not significantly impact groundwater quantities. Impacts related to improper 

drilling techniques would not be considered significant for Criteria 1, 2 and 3 due to the use of state-ofthe-art drilling and well-completion techniques included in the BLM’s Onshore Oil and Gas Order No. 2 

and the BMPs and COAs related to drilling that would be implemented. If disposal wells are installed 

according to EPA and WDEQ requirements and if BMPs and COAs related to handling of fluids are 

implemented, the likelihood of degradation of groundwater as a result of water disposal would be limited 

and impacts would not be considered significant for Criterion 2. State-of-the-art pit and pipeline 

construction techniques, including the use of pit liners and hydrostatic pressure testing, would protect the 

groundwater resource and impacts from spills resulting from Alternative C would not be considered 

significant for Criteria 2 and 3. 

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4.4.4.6 Alternative D: Directional Drilling 

The types of impacts for Alternative D would be the same as those described in Section 4.4.4.1, but 

would be reduced in magnitude when compared to the Proposed Action because of the decrease in initial 

and long-term disturbance. Under Alternative D, 4,032 pads would be required for the drilling of 8,950 

wells. Total construction-phase surface disturbance would be 36,449 acres, 23 percent less than the 

Proposed Action. All natural gas wells on public lands and federal mineral estate would be drilled from 

multi-well pads. In sections that have not had oil and gas development at all, one new well pad would be 

permitted for all future development. No numerical disturbance caps, no rollover credits, and no new 

requirements on reclamation are part of this alternative. 

Surface Water. Impacts to surface water would be less in magnitude than those for the Proposed Action 

due to the significant reduction in the amount of surface disturbance. Alternative D has the least amount 

of surface disturbance of the action alternatives. 

Impacts from both authorized and accidental surface discharge of fluids related to surface water would 

not be considered significant for Criteria 1, 2, 3, 4, and 7 considering the decrease in the amount of 

surface disturbance. 

Impacts related to disturbance/sediment loading would be considered significant for Criteria 2 and 6. 

Impacts related to the disturbance/sediment loading would not be considered significant for Criteria 1, 3, 

4, 5, and 8. This is largely the result of reduced disturbance acreage compared with the Proposed Action. 

Groundwater. Because this alternative reduces the number of well pads, the risk of contamination of the 

groundwater resource would decrease compared to the Proposed Action due to the decreased probability 

of a pad being near a water well or above a shallow aquifer, which, by proximity, raises the chance of 

contamination resulting from leaks, spills, or improper drilling techniques, especially poor well casing 

and cementing practices. 

Impacts related to groundwater removal would not be considered significant for Criterion 1 since the 

source aquifers for the springs and seeps are stratigraphically higher than the natural gas exploration 

targets and the areas in the vicinity of flowing wells can be avoided when and if new water supply wells 

are developed. Due to the amount of available groundwater in storage, groundwater removal resulting 

from Alternative D would not significantly impact groundwater quantities. Impacts related to improper 

drilling techniques would not be considered significant for Criteria 1, 2 and 3 due to the use of state-ofthe-art drilling and well-completion techniques included in the BLM’s Onshore Oil and Gas Order No. 2 

and the BMPs and COAs related to drilling that would be implemented. If disposal wells are installed 

according to EPA and WDEQ requirements and if BMPs and COAs related to handling of fluids are 

implemented, the likelihood of degradation of groundwater as a result of water disposal would be limited 

and the potential of meeting or exceeding Criterion 2 would be low. State-of-the-art pit and pipeline 

construction techniques, including the use of pit liners and hydrostatic pressure testing, would protect the 

groundwater resource and impacts from spills resulting from Alternative D would not be considered 

significant for Criteria 2 and 3. 

4.4.4.7 Alternative E: No Action 

Under the No Action Alternative (Section 2.2.6), there would be no new surface water or groundwater 

impacts. 

4.4.5 Summary of Impacts 

All action alternatives would result in increased natural gas development in the CD-C project area, with 

the principal difference between the alternatives being the amount of surface disturbance. Surface water 

impacts resulting from drill pad, access road, facility site, and pipeline right-of-way disturbance would 

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include: increased sediment loads due to removal of vegetation; exposure of the soil; mixing of soil 

horizons; soil compaction; and changes in water quality, channel geometry, and channel stability. 

Groundwater impacts would result from the removal of groundwater and subsurface disposal (injection) 

of produced water. Impacts to groundwater could also be caused by improper drilling operations— 

especially poor well casing and cementing practices—and by accidental releases of fluids associated with 

drilling operations, produced water, and other hazardous liquids to soils and surface-water systems. The 

following discussion reviews impacts by alternative and discusses the potential to meet or exceed 

significance criteria for surface water and groundwater for each action alternative. The evaluation 

assumes successful implementation of state-of-the-art drilling and well-completion techniques included in 

the BLM’s Onshore Oil and Gas Order No. 2 and the BMPs and COAs included in Appendix C. Table 

4.4-1 summarizes the impacts discussion. 

Table 4.4-1. The potential for Significant (S) or Not Significant (NS) impacts for surface water and 

groundwater significance criteria. 

Surface-Water Significance Criteria 

1 2 3 4 5 6 7 8 

Proposed Action S S NS NS NS S NS S 

Alternative A S S S S S S S S 

Alternative B NS NS NS NS NS S NS NS 

Alternative C NS S NS NS NS S NS NS 

Alternative D NS S NS NS NS S NS NS 

Groundwater Significance Criteria 

1 2 3 

Proposed Action NS NS NS 

Alternative A NS NS NS 

Alternative B NS NS NS 

Alternative C NS NS NS 

Alternative D NS NS NS 

A summary of the water resources impact significance criteria is included here. The full description of the 

criteria is found in Section 4.4.3.1, Surface Water Significance Criteria, and Section 4.4.3.2 

Groundwater Significance Criteria. 

Surface-Water Significance Criteria 

1. Degradation of water quality. 

2. Elevated salt-loading to the Colorado River system. 

3. Loss of wetlands or wetland function. 

4. Degradation of wetland/riparian areas. 

5. Alteration of streamflow characteristics. 

6. Alteration of stream-channel geometry or gradient. 

7. Surface water contamination from spilled fluids. 

8. Soil loss greater than 2 tons per acre per year. 

Groundwater Significance Criteria 

1. Impairment of springs, seeps, or flowing artesian wells. 

2. Degradation of groundwater quality in any aquifer. 

3. Groundwater contamination from spilled fluids. 

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Under the Proposed Action, 6,126 pads would be required for 8,950 wells. The primary surface water 

impacts of the Proposed Action would be brought about by contamination from the authorized and 

accidental discharge of fluids and the impacts from surface disturbance related to project development 

and maintenance. Groundwater impacts would occur during the removal of groundwater and through 

subsurface disposal (injection) of produced water. Impacts to groundwater could also be caused by 

improper drilling operations and from accidental releases of fluids (spills). Impacts to surface water 

would be considered significant for Criteria 1, 2, 6, and 8, depending on the locations of the drill pads and 

associated roads and pipelines. Impacts would not be considered significant for groundwater. 

Alternative A (100-Percent Vertical Drilling) assumes that all of the wells would be drilled vertically, 

resulting in an increase in the number of pads (to 8,950) and associated roads and pipelines. Alternative A 

would increase the amount of construction-phase surface disturbance by 31 percent compared to the 

Proposed Action. The types of surface water and groundwater impacts would be the same as for the 

Proposed Action but the magnitude of the impacts would increase. Impacts to surface water would be 

considered significant for all eight criteria. Impacts would not be considered significant for groundwater. 

Alternative B (Enhanced Resource Protection) would reduce the number of pads (to 5,798) and reduce the 

amount of construction-phase surface disturbance by nearly 4 percent compared to the Proposed Action. 

The magnitude of surface water impacts would decrease when compared to the Proposed Action as a 

result of the reduced number of well pads—and hence the amount of surface disturbance—and 

specifically from the enhanced protection of the Muddy Creek watershed. Impacts to surface water would 

be considered significant for Criterion 6. Impacts would not be considered significant for groundwater. 

Alternative C (Surface Disturbance Cap—60 Acres and 30 Acres per Section) would reduce the number 

of pads (to 5,229) and thus reduce the amount of surface disturbance by 9 percent compared to the 

Proposed Action, which would reduce the magnitude of surface-water impacts. In addition to the 

reduction of surface disturbance, the aim of this alternative is to encourage improved reclamation success, 

primarily through increased directional drilling. Impacts to surface water would be considered significant 

for Criteria 2 and 6. Impacts would not be considered significant for groundwater. 

Alternative D (Directional Drilling) would reduce the amount of construction-phase surface disturbance 

by 23 percent compared to the Proposed Action, which would reduce the magnitude of surface-water 

impacts. This alternative reduces surface disturbance primarily through increased directional drilling, 

which would reduce the number of pads (to 4,032) and associated roads, pipelines, and other facilities. 

This alternative has the least amount of surface disturbance of the action alternatives. Impacts to surface 

water would be considered significant for Criteria 2 and 6. Impacts would not be considered significant 

for groundwater. 

Under Alternative E (No Action Alternative), it is assumed that the development activities proposed by 

the CD-C Operators would not occur and there would be no new surface water or groundwater impacts. 

4.4.6 Unavoidable Adverse Impacts and Additional Mitigation Measures 

Surface Water. All of the impacts defined in the eight surface water significance criteria (Section 

4.4.3.1) would be mitigated to some extent by the measures found in the BMPs and COAs in Appendix C 

and by the measures found in state and federal law and regulation. Some of the impacts would be further 

mitigated by provisions of the different alternatives. For the most part, loss of wetland function and 

degradation of wetland/riparian areas (Criteria 3 and 4), alteration of streamflow characteristics (Criterion 

5), and contamination from spilled industrial fluids and produced water (Criterion 7) would be addressed 

by these existing protections and mitigations. The exception is Alternative A where surface disturbance 

would be at such a level that impacts would not be adequately mitigated. 

Total surface disturbance also contributes to the exceedance of significance criteria related to degradation 

of water quality and potential soil loss (Criteria 1 and 8). Under the Proposed Action and Alternative A, 

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total surface disturbance would be great enough that existing protection and mitigation measures would 

not necessarily prevent exceedance of significance levels for these criteria. Alternative B specifies an 

increase in set-back distances within the Muddy Creek watershed, from 500 feet to 0.25 mile for springs, 

wells, and wetlands and to 0.5 mile from perennial streams. This increased set-back would ensure that 

Criteria 1 and 8 are not exceeded if state and private lands are included in the set-back. The reduction in 

surface disturbance brought about by Alternatives C and D (9 and 23 percent, respectively) combined 

with existing mitigation measures would reduce the likelihood of these alternatives exceeding Criteria 1 

and 8. 

Alternative B would also avoid exceedance of Criterion 2—salt loading—because of the increased setback. The Proposed Action and Alternatives A, C, and D would exceed Criterion 2. 

Criterion 6—alteration of stream-channel geometry or gradient by accelerated runoff and erosion—would 

be exceeded by the Proposed Action and all action alternatives. 

Impacts could be reduced for the Proposed Action and Alternatives A, C, and D with the application of 

features found in Alternative B. Increased set-back distances would decrease impacts with regard to 

Criteria 1 through 4. Such a measure would be most effective if private and state lands were included in 

the setback. Implementation of preconstruction planning and design activities that emphasize proper 

placement, construction, and maintenance of roads, culverts, drainage ditches would also reduce impacts. 

Alternatives C and D would have reduced impacts with regard to all the significance criteria because they 

are structured to decrease both the number of well pads—disturbance sites—as well as the total acreage of 

disturbance. Any measures applied to the Proposed Action or Alternatives A and B that decrease the 

number of disturbance sites and the amount of surface disturbance would also reduce the risk of those 

alternatives exceeding the significance criteria. 

Groundwater. Groundwater resources would not incur significant adverse impacts with the appropriate 

application of protections and mitigation measures found in Appendix C and in state and federal laws 

and regulations. No additional mitigation measures would be necessary. 

4.5 AIR QUALITY 

4.5.1 Introduction 

The air quality analysis addresses the potential impacts on ambient air quality and Air Quality Related 

Values (AQRVs) from air emissions due to the Proposed Action and alternatives and from other regional 

emissions sources within a defined study area. Potential ambient air quality impacts were quantified and 

compared to applicable state and Federal ambient air quality standards and Prevention of Significant 

Deterioration (PSD) increments, hazardous air pollutant (HAP) thresholds, and AQRV impacts (impacts 

on visibility, atmospheric deposition, and potential increases in acidification to acid-sensitive lakes) were 

determined and compared to applicable thresholds. 

A near-field ambient air quality impact assessment was performed to evaluate maximum pollutant 

impacts within and adjacent to the CD-C project area resulting from project-related development and 

production emissions. The EPA's Guideline (EPA, 2005) model, AERMOD (version 11353), was used to 

assess these near-field impacts. The near-field criteria pollutant assessment was performed to estimate 

maximum impacts of CO, oxides of nitrogen (NOx), SO2, PM10, and PM2.5 from project emissions 

sources that are likely to operate during the development and production phases of the Proposed Action 

and alternatives. Near-field HAP (benzene, toluene, ethyl benzene, xylene, n-hexane and formaldehyde) 

concentrations were calculated for assessing impacts both in the immediate vicinity of project area 

emission sources for short-term (acute) exposure assessment and for calculation of long-term risk. 

A far-field ambient air quality impact assessment was carried out to quantify potential air quality impacts 

to both ambient air concentrations and AQRVs from air pollutant emissions of CO, NOx, SO2, PM10, 

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PM2.5, and volatile organic compounds (VOCs) expected to result from the development of the CD-C 

project as well as the combined effects of the CD-C project and other new sources of emissions in the 

region. 

The far-field analysis described in this document differs significantly from previous natural gas 

development EIS air quality analyses performed for the BLM in Wyoming. Previous BLM analyses used 

the CALPUFF dispersion model to assess AQRV impacts in nearby PSD Class I Areas and sensitive PSD 

Class II Wilderness Areas from project and cumulative source emissions. For the CD-C impact analysis, 

the BLM and Wyoming Department of Environmental Quality Air Quality Division (WDEQ-AQD) 

elected to use the CAMx (Comprehensive Air quality Model with Extensions; ENVIRON 2010) 

photochemical grid model (PGM), which is a type of computer model that simulates the formation, 

transport, and fate of ozone and other pollutants in the atmosphere. PGMs represent the “state of the 

science” in tools and methods for both air quality (including ozone) and AQRV analyses. CAMx was 

used to predict maximum potential ambient air quality and AQRV impacts at mandatory federal PSD 

Class I and other sensitive PSD Class II areas, as well as designated acid-sensitive lakes. The CAMx 

analysis includes mid-field analyses which quantify impacts within the CD-C project area. Mid-field air 

quality impacts are compared to applicable ambient air quality standards. 

The far-field modeling approach was determined by ozone air quality levels in Wyoming. Recent high 

levels of observed ozone dictated the choice of far-field modeling tools and methods. Ozone (O3) is an 

important component of photochemical smog. Ozone is not emitted directly into the atmosphere, but is 

formed from photochemical reactions of precursor species in the presence of sunlight. The most important 

precursors are NOx and VOCs. High ozone episodes occur most typically in urban areas during summer. 

Under these conditions, there is an abundance of ozone precursors from human activities and the high 

angle of the summer sun means there is sufficient sunlight available to drive the photochemical reactions 

which produce ozone. High summer temperatures enhance VOC emissions and speed the chemical 

reactions which produce ozone from its precursors. 

In 2005, high ozone was measured in Sublette County, WY during winter. The phenomenon of winter 

high ozone under conditions with low sun angles and cold temperatures was novel, particularly because 

Sublette County is a relatively rural area whose main source of emissions is oil and gas exploration and 

production. High ozone levels were recorded again in Sublette County in 2006, 2008, and 2011. High 

winter ozone has also been measured in the Uinta Basin region in rural eastern Utah in recent years. Oil 

and gas production also occurs in the Uinta Basin. 

In March 2009 the Governor of Wyoming recommended to the EPA that Sublette County and parts of 

northeastern Lincoln and northwestern Sweetwater Counties be designated ozone non-attainment areas 

under the 2008 75 parts per billion (ppb) ozone standard. Because of the importance of ozone as an air 

quality issue in Wyoming, the CD-C air quality impact analysis included evaluation of the effects of 

emissions from the Proposed Action on ozone throughout the study area (Map 3.5-1).. 

The CD-C project area is located in eastern Sweetwater and western Carbon Counties. Although the 

project does not lie within the area proposed for non-attainment designation, the CD-C impact analysis 

evaluated potential ozone impacts from the Proposed Action emissions on ozone in Sublette, northeastern 

Lincoln, and northwestern Sweetwater Counties as well as the rest of the study area. 

An emission inventory was developed for the Proposed Action and alternatives for each year over the 

expected life of the project. This emission inventory was used in the near-field, mid-field and far-field 

analyses. Emission inventories for all regional emissions sources from human activities and natural 

sources (e.g. wildfires) were compiled for use in the far-field modeling. In the following sections, the 

emission inventory development is described. Next, the modeling approaches for both near- and far-field 

analyses are detailed, and finally, the results of the analyses are given. 

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4.5.2 Management Objectives and Impact Significance Criteria 

The Rawlins RMP (BLM 2008a) prescribes the following management objectives and impact significance 

criteria associated with air quality: 

Management Objectives 

1.	 Maintain concentrations of criteria pollutants associated with management actions in compliance 

with applicable state and federal ambient air quality standards. 

2.	 Maintain concentrations of PSD pollutants associated with management actions in compliance with 

the applicable increment. 

3.	 Reduce visibility-impairing pollutants in accordance with the reasonable progress goals and time 

frames established within the State of Wyoming’s Regional Haze State Implementation Plan (SIP). 

4.	 Reduce atmospheric deposition pollutants to levels below generally accepted Levels of Concern and 

Limits of Acceptable Change. 

Significance Criteria 

If and when specific activities are proposed at the implementation stage requiring quantitative analysis, 

impacts to air quality would be compared to the following significance criteria: 

 The National Ambient Air Quality Standards (NAAQS) or Wyoming Ambient Air Quality
 

Standards (WAAQS) 

 The applicable PSD increments 

 Federal guidelines for visibility impairment and atmospheric deposition. 

More detailed information on the significance criteria is included in Section 3.5.2. 

4.5.3 Emission Inventory Development 

4.5.3.1 CD-C Project Alternative Emission Inventory Development 

Emission inventories for CD-C project area development and production activities were compiled for the 

air quality impact assessment for all existing sources and for all new sources associated with the Proposed 

Action and alternatives. 

There are two different types of activities (field development and production) associated with the CD-C 

project for which emission inventories were compiled. Emission-generating activities during field 

development include well pad and access road construction, drilling, fracking/completion, vehicle travel 

during the drilling and completion phase, and construction and vehicle travel during installation of 

gathering and sales pipeline systems. Production emissions were calculated for dehydration units, 

separators, gathering pipelines, blowdown tanks, and water/condensate storage tanks. Ancillary facilities 

included new compressor engines at current and proposed sites as well as central gas processing facilities. 

The specific components of field development and production emissions and total field-wide emissions 

are discussed in the Air Quality Technical Support Document (AQTSD) and its Appendices (available on 

the CD-C Natural Gas Development Project EIS website). 

The CD-C project emission inventory was developed using data from the CD-C Operators as the primary 

source of information. The inventory accounted for all applicable emissions controls such as New Source 

Performance Standards (NSPS) and new Tier standards for non-road engines. The most important of these 

emissions controls are those specifically targeted at Wyoming oil and gas sources. 

The WDEQ-AQD regulates emissions from oil and gas sources through the Oil and Gas Permitting 

Guidance (WDEQ-AQD, 2010). Different regulations apply in different regions of the state, with the 

most stringent level of controls applied to the areas with highest measured ambient ozone concentrations 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 4-41 
 

 

   

CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—AIR QUALITY
 

that occur in the Jonah-Pinedale Anticline Development (JPAD) area shown in Figure 4.5-1. The CD-C 

project lies within a region of intensive oil and gas development known as the Concentrated Development 

Area (CDA). Under the WDEQ-AQD 2010 guidance, emissions controls are required in the CDA for the 

following source categories: 

 Tank flashing
 

 Dehydration units 

 Pneumatic pumps
 

 Pneumatic controllers 

 Produced-water tanks 

 Blow-down / venting 

Figure 4.5-1. The Concentrated Development Area (CDA) 

Source: WDEQ-AQD, 2010 

These control measures were taken into account in the development of the CD-C project emission 

inventory. Table 4.5-1 shows the emissions control measures for each emissions source category modeled 

in this analysis. 

4-42 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
 

 

CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—AIR QUALITY 

Table 4.5-1. Modeled CD-C project emissions control measures 

CD-C Project Emissions Source Category Type of Control Applied 

Well Pad Const Equipment (diesel ICE) Change in fuel sulfur content 

Completion Equipment (diesel ICE) Change in fuel sulfur content 

Construction Traffic, Road and Well Pad Change in emissions due to fleet turnover 

Construction Traffic, Road and Well Pad – 

Fugitive Dust 

Watering 

Drilling Equipment (diesel ICE) Change in fuel sulfur content and emission reductions due to Tier 2 

engine technology 

Drilling Traffic Change in emissions due to fleet turnover 

Drilling Traffic – Fugitive Dust Watering 

Completion Traffic Change in emissions due to fleet turnover 

Completion Traffic – Fugitive Dust Watering 

Completion Venting 96% of Gas to Green Completions and 4% of Gas Flared 

Completion Flaring N/A 

Well Pad and Access Road Construction – 

Fugitive Dust 

Watering 

Construction Wind Erosion – Fugitive Dust None 

Workover Equipment (diesel ICE) Change in fuel sulfur content 

Workover Rig Traffic Change in emissions due to fleet turnover 

Workover Rig Traffic – Fugitive Dust Watering 

Heaters None 

Fugitives None 

Pneumatic Devices No bleed devices 

Pneumatic Pump WDEQ BACT 

Dehydrator Venting WDEQ BACT 

Tank Loadout (vapor losses) None 

Well Venting None 

Production Traffic Change in emissions due to fleet turnover 

Production Traffic - Fugitive Dust Watering 

Condensate Tank Flashing Losses WDEQ BACT 

Condensate Tank Working Losses WDEQ BACT 

Condensate Tank Breathing Losses WDEQ BACT 

Production Flaring --

Compressor Station WDEQ BACT assumed to limit NOx and CO emissions for reciprocating 

engines 

Gas Plant WDEQ BACT assumed to limit NOx and CO emissions for reciprocating 

engines 

Evaporation Ponds None 

The field-wide emissions for the Proposed Action and alternatives are summarized in Table 4.5-2. The 

first column shows emissions for existing project area sources in the year 2008. The second column 

shows emissions from these 2008 sources within the project area forecast to the year 2022. These 

emissions represent the No Action Alternative in which the CD-C project is not developed. The Proposed 

Action column shows emissions from Proposed Action sources in the year 2022, and the total project area 

emissions in year 2022 gives the sum of emissions from existing sources and Proposed Action sources 

within the CD-C project area. The column furthest to the right shows the difference in emissions between 

the total CD-C field wide emissions in 2022 and year 2008 field-wide emissions. Year 2022 emissions are 

shown since the peak emissions for the Proposed Action alternative are estimated to occur during 2022. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 4-43 
 

 

 

CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—AIR QUALITY
 

Table 4.5-2. CD-C project alternative emission summary (tpy) 

Pollutant 

2008 

Existing 

Project 

No Action 

2022 

Proposed 

Action 2022 

Total 

Project Area 

2022 

2008 to 2022 Increase in 

Emissions Resulting 

from Proposed Action 

and No Action 

Alternatives 

NOx 3,587 1,757 4,959 6,715 3,129 

CO 3,185 1,852 8,621 10,473 7,289 

SO2 135 2 2 4 -131 

PM10 1,352 498 2,255 2,753 1,401 

PM2.5 403 203 475 678 275 

VOC 58,672 42,249 14,791 57,039 -1,633 

4.5.4 Greenhouse Gases 

The U.S. Supreme Court ruled in 2007 that the EPA has the authority to regulate greenhouse gases 

(GHGs) such as methane (CH4) and carbon dioxide (CO2) as air pollutants under the Clean Air Act; 

however, there are currently no ambient air quality standards for GHGs, nor are there currently any 

emissions limits on GHGs that would apply to sources developed under the Proposed Action and 

alternatives. There are, however, applicable reporting requirements under the EPA’s Greenhouse Gas 

Reporting Program. These GHG emission reporting requirements, finalized in 2010 under 40 CFR Part 

98, will require the CD-C project proponents to develop and report annual methane and CO2 emissions 

from equipment leaks and venting, and emissions of CO2, methane and nitrous oxide from flaring, 

onshore production stationary and portable combustion emissions, and combustion emissions from 

stationary equipment. At present, there are no rules related to GHG emissions or impacts that would affect 

development of the Proposed Action and action alternatives, besides these GHG reporting requirements. 

Both the exploration/construction and production phases of the Proposed Action and the development 

alternatives will cause emissions of GHGs. Methane comprises much of the chemical composition of 

natural gas, and nitrous oxide, CO2, and methane are emitted by engines used for drill rigs, compressor 

engines, etc. As part of the development of the CD-C project emission inventory, an inventory of CO2, 

methane, and nitrous oxide was prepared for all emissions source categories. GHGs were not modeled in 

either the near-field or far-field impact analyses, but the GHG inventory is presented here for 

informational purposes and is compared to other U.S. GHG emission inventories in order to provide 

context for the CD-C project GHG emissions. This inventory is presented in the AQTSD, Section 2.1.6. 

In the CD-C project emission inventory, emissions of the greenhouse gases CO2, CH4, and N2O from new 

and existing sources are quantified in terms of CO2 equivalents. Measuring emissions in terms of CO2 

equivalents allows for the comparison of emissions from different GHGs based on their Global Warming 

Potential (GWP). GWP is defined as the cumulative radiative forcing of a gas over a specified time 

horizon relative to a reference gas resulting from the emission of a unit mass of gas. The reference gas is 

taken to be CO2. The CO2 equivalent emissions for a greenhouse gas are derived by multiplying the 

emissions of the gas by the associated GWP. The GWPs for the inventoried GHGs are CO2:1, CH4:21, 

N2O:310 (EPA, 2011). Details of the greenhouse gas emissions calculations are provided in the AQTSD 

(greenhouse gas emissions over the life of the project are shown in AQTSD Figure 2-13.) The CD-C 

project’s peak CO2 equivalent emissions year will be 2022. Field-wide GHG emissions for the existing 

project in year 2008, the existing 2008 project projected for year 2022 (No Action Alternative), the CD-C 

Proposed Action in year 2022, the total project area emissions in year 2022 (existing sources taken 

together with the Proposed Action), and the difference in emissions between the total CD-C field 

emissions (including the Proposed Action emissions) and year 2008 field-wide emissions are summarized 

in Table 4.5-3. 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—AIR QUALITY 

Table 4.5-3. CD-C project alternative GHG emission summary (metric tpy) 

Pollutant 2008 Existing 

Project 

No Action 

2022 

Proposed 

Action 2022 

Total Project 

Area 2022 

2022-2008 Increase in 

Emissions Resulting 

from Proposed Action 

and No Action 

Alternatives 

CO2 3,396,718 3,155,654 4,328,247 7,483,901 4,087,183 

CH4 89,165 76,097 38,291 114,388 25,223 

N2O 91 75 67 142 51 

CO2e* 5,298,295 4,777,792 5,153,746 9,931,538 4,633,242 

* CO2 equivalent 

4.5.5 Regional Emission Inventory Development 

In addition to the CD-C project emissions, emission inventories for other regional existing and proposed 

emissions sources within a continental-scale modeling domain (Map 4.5-1) were constructed and used for 

cumulative modeling analyses. Emission inventories prepared by the Western Regional Air Partnership 

(WRAP), Carter Lake, and BP and other Operators formed the basis for the regional emission inventories 

for the CD-C project far-field air quality impact analysis. Sources of PM10, PM2.5, NOx, CO, SO2, and 

VOC emissions within the study area were inventoried. Emission inventories and projections from 

various state and federal agencies were used to update the WRAP analyses as appropriate for each of the 

years modeled. Three categories of regional emissions inventories were compiled: two base case years 

(2005-6), a baseline year (2008), and a future year (2022). These inventories are described in detail in the 

AQTSD and its Appendices. The project and regional emissions were used in air quality modeling 

analysis of near-field and far-field impacts. 

Map 4.5-1. Study area showing 36/12/4 kilometer (km) nested modeling grid used for photochemical 

grid modeling (left panel) and expanded view of the 4-km domain that was the focus of the 

far-field modeling impact analysis showing boundary of CD-C project area (yellow) and 

nearby Class I/sensitive Class II areas. 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 4-45 
CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—AIR QUALITY
 

4.5.6 Air Quality Modeling 

4.5.6.1 Near-Field Modeling 

A near-field ambient air quality impact assessment was performed to evaluate maximum pollutant 

impacts within and adjacent to the CD-C project area resulting from the Proposed Action and alternative 

development and production emissions. AERMOD (version 11353), combined with three years (2008­

2010) of hourly meteorological data collected near Wamsutter, Wyoming were used in the analysis to 

assess these near-field impacts. The near-field criteria pollutant assessment was performed to estimate 

maximum potential impacts of CO, NOx, SO2, PM10, and PM2.5 from project emissions sources that are 

likely to operate during the development and production phases of the Proposed Action and action 

alternatives. Production activities include well production, expanded field compression and a new gas 

processing facility. Well field development activities that were modeled included well pad and access 

road construction, and well drilling. Modeling scenarios were also developed that included wells in 

production in close proximity to well pads where well drilling operations are occurring. 

For 1-hour NO2 NAAQS compliance demonstrations, where 1-hour NAAQS is defined as the 3-year 

average of the 98th percentile of the yearly distribution of 1-hour daily maximum concentrations, all 

modeled impacts presented represent the 3-year average of the eighth-highest daily maximum 1-hour 

concentrations. For scenarios where drilling operations were modeled, drilling operations were assumed 

to occur for a maximum of 2 years during the 3-year averaging period. Since drill rigs move to different 

locations during field development, it is not likely that a drilling operation would occur over 3 

consecutive years in the same location. 

For all criteria pollutant modeling scenarios, two model receptor grids were used for disclosing modeled 

impacts: one assuming a 100-meter distance from project sources, and another using a 250-meter distance 

from project sources. Representative background pollutant concentrations were added to modeled impacts 

and the total impacts compared to applicable Wyoming and National Ambient Air Quality Standards 

(WAAQS and NAAQS). Direct modeled pollutant impacts from project emission were compared with 

applicable PSD Class II increments. The comparisons to the PSD Class II increments are intended to 

evaluate a threshold of concern for potential impacts and do not represent a regulatory PSD increment 

comparison. 

Near-field HAP (benzene, toluene, ethyl benzene, xylene, n-hexane and formaldehyde) concentrations 

were calculated for assessing impacts both in the immediate vicinity of project alternative sources for 

short-term (acute) exposure assessment and for calculation of long-term risk. Short-term (1-hour) HAP 

concentrations were compared to acute Reference Exposure Levels (RELs). Long-term exposures to 

HAPs emitted by project alternative sources were compared to Reference Concentrations for Chronic 

Inhalation (RfCs), and were evaluated based on estimates of the increased latent cancer risk over a 70­

year lifetime. Two estimates of cancer risk were made: one that corresponds to a most-likely-exposure 

(MLE) over a national residency average of 9 years with some time spent away from home, and one 

reflective of the maximally-exposed-individual (MEI) residing at one location for a lifetime with no time 

spent away from home. The cancer risks for all constituents were then summed to provide an estimate of 

the total inhalation cancer risk. 

For all HAP modeling scenarios, 100-meter and 250-meter receptor distances from project sources were 

used. In addition, for risk assessments the distance from a source where the cancer risk is expected to fall 

below the level of one in one million is disclosed. 

4.5.6.1 Far-Field Modeling 

The purpose of the far-field modeling was to quantify potential air quality impacts to both ambient air 

concentrations and AQRVs from air pollutant emissions of NOx, SO2, PM10, PM2.5, VOC, and CO 

expected to result from the development of the CD-C project as well as the combined effects of the CD-C 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—AIR QUALITY
 

project and other new sources of emissions in the region. The CAMx model was used to estimate impacts 

throughout the study area shown in the right-hand panel of Map 4.5-1. Impacts were estimated using two 

meteorological modeling years (2005 and 2006). Wind fields for these two meteorology years were 

developed using the PSU/NCAR Mesoscale Model version 5 (MM5; Anthes and Warner 1978; Dudhia 

1993). 

The PSD Class I areas and sensitive PSD Class II areas analyzed in the far-field analyses include the 

following: 

 Bridger Wilderness Area, Wyoming (Class I); 

 Fitzpatrick Wilderness Area, Wyoming (Class I); 

 Savage Run Wilderness Area, Wyoming (Federal Class II, Wyoming Class I) 

 Mount Zirkel Wilderness Area, Colorado (Class I); 

 Rawah Wilderness Area, Colorado (Class I); 

 Popo Agie Wilderness Area , Wyoming (Class II); 

 Wind River Roadless Area, Wyoming (Class II); and 

 Dinosaur National Monument, Colorado-Utah (Federal Class II, Colorado Class I (SO2 only). 

Twelve lakes within the Class I and sensitive Class II areas were identified as being sensitive to 

atmospheric deposition, as follows: 

Bridger Wilderness Area, Wyoming Mount Zirkel Wilderness Area, Colorado 

 Black Joe Lake  Lake Elbert 

 Deep Lake  Seven Lakes 

 Hobbs Lake  Summit Lake 

 Upper Frozen Lake Rawah Wilderness Area, Colorado  Lazy Boy Lake 

 Island Lake Fitzpatrick Wilderness Area, Wyoming  Rawah Lake #  Ross Lake 

Popo Agie Wilderness Area, Wyoming 

 Lower Saddlebag Lake 

The CAMx model was used to estimate ambient air quality impacts of CO, NO2, SO2, O3, PM10, and 

PM2.5 throughout the study area, and to estimate nitrogen and sulfur deposition at the Class I and sensitive 

Class II areas. CAMx concentration estimates were used to calculate visibility impacts at the Class I and 

sensitive Class II areas. Impacts to potential sensitive lake acidification were calculated using CAMx 

estimated sulfur and nitrogen deposition values. 

The impact analysis includes an assessment of CD-C project source contributions to regional ozone 

formation, comparisons of modeled criteria pollutant impacts to applicable Class I and Class II 

increments at the Class I and sensitive Class Il areas, and assessments of project impacts to AQRVs 

(visibility, atmospheric deposition, and sensitive lake acidification) at the Class I and sensitive Class II 

areas compared with applicable threshold values. The far-field analysis includes mid-field criteria 

pollutant analyses which compare CAMx-estimated criteria pollutant levels within the CD-C project area 

to applicable ambient air quality standards. 

Far-Field Modeling Approach 

The basic modeling strategy used in any analysis that employs a photochemical grid model, such as 

CAMx, is to first evaluate the ability of the model to reproduce ambient observations of trace pollutants 

during a recent historical episode (the “current year” or “base case year”); then, once confidence in the 

model is established, a future year case can be run and the potential impacts of the project evaluated. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 4-47 
CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—AIR QUALITY
 

A current year base case is simulated using a comprehensive regional emission inventory of actual 

emissions from all sources (including motor vehicles, power plants, oil and gas exploration and 

production sources, biogenic sources, etc.). It is preferable to run the model for more than one year so that 

as many different meteorological regimes as possible are simulated. Pollutants emitted from project 

sources may only influence a particular sensitive receptor under certain conditions (wind direction, 

atmospheric stability) and a conservative estimate of AQ and AQRV impacts requires that those 

conditions be simulated. While it is not possible to ensure that all possible meteorological conditions that 

might lead to transport of pollutants from project sources to sensitive receptors are simulated, modeling 

two full years increases the likelihood that the relevant conditions would occur. 

The base case simulation is evaluated with respect to ambient air quality measurements. If the base case 

simulation reproduces concentrations of observed species with reasonable accuracy, then the model can 

be used in the future year impact assessment. The next step is to prepare a baseline model for use in future 

year projections. The only difference between the base case model and the baseline model is that the 

baseline model uses typical emissions while the base case model uses actual emissions. An example of an 

emissions source category for which the base case and baseline emissions are different is electrical 

generating units (EGUs). The base case emission inventory uses hourly EGU emissions derived from 

continuous emissions monitoring (CEM) data because the base case model is evaluated against concurrent 

observations to determine whether the model provides a realistic simulation of atmospheric processes. 

The purpose of the baseline model, on the other hand, is to serve as the base year from which future year 

projections are made. The baseline EGU emissions are used to represent typical conditions (no shutdowns 

for maintenance, for example) in order to be consistent with the future year emissions, which also 

represent typical conditions. The baseline emission inventory, therefore, is usually identical to the base 

case emission inventory, except for the difference in emissions from EGUs and other source categories 

with large variability in time, such as drill rigs. 

The future year modeling involves development of a future year project emission inventory as well as a 

future year regional emission inventory. In the future year regional emission inventory, the emissions 

from human activities are projected from the base year to the future year and changes such as population 

growth and planned emissions controls (such as controls on motor vehicle emissions) are accounted for. 

Emissions that are not controllable, such as biogenics and wildfire emissions, are held fixed. The project 

emissions are included in the future year emission inventory. The model is run using the future year 

regional emission inventory with the rest of the model (meteorological fields, boundary conditions, model 

settings, etc.) in the same configuration as in the base case. If multiple years were simulated in the base 

case, then the meteorological conditions for those same years are used together with the future year 

emissions scenario in the future year modeling. Project AQ and AQRV impacts are determined from the 

future year simulations. 

In the CD-C analysis, CAMx was used to perform modeling of the base case years (2005-6), the baseline 

year (2008), and the future year (2022). 

4.5.7 Direct and Indirect Impacts 

Direct, indirect, and cumulative air quality impacts were analyzed to predict maximum potential nearfield (surrounding the CD-C project area), mid-field (within the CD-C project area) and far-field (regional 

and PSD Class I and sensitive PSD Class II areas) ambient air pollutant concentrations, as well as 

maximum impacts to visibility (regional haze), and atmospheric deposition (acid rain) impacts. Analyses 

were also performed to predict maximum mid-field (within the CDC-project area) pollutant 

concentrations. Summaries of the impacts for each of the Proposed Action and alternatives are provided 

below. 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—AIR QUALITY
 

4.5.7.1 Proposed Action 

The Proposed Action includes the construction and operation of 8,950 natural gas wells, associated roads 

and production facilities, including compression and gas processing facilities. The proposed natural gas 

wells would be drilled either conventionally (with a single vertical well bore on each well pad) or with 

multiple directional well bores from a single pad. 

Near-Field Modeling 

Near-field modeling analyses were performed for the Proposed Action production and well field 

development activities. Criteria pollutant impacts were evaluated for both production and construction 

activities; however, HAP pollutant impacts were evaluated for only production activities since HAP 

emissions result primarily from well production activities. Production activities include well production, 

expanded field compression and a new gas processing facility. Well field development activities that were 

modeled included well pad and access road construction, and well drilling. Modeling scenarios were also 

developed that included wells in production in close proximity to well pads where well drilling operations 

are occurring, including a case where four drill rigs are operating within one land section. Two model 

receptor grids were used for disclosing modeled impacts; one assuming a 100-meter distance from project 

sources, and another using a 250-meter distance from project sources. 

For 1-hour NO2 NAAQS compliance demonstrations, all modeled impacts represent the 3-year average of 

the eighth-highest daily maximum 1-hour concentrations. For scenarios where drilling operations were 

modeled, drilling operations were assumed to occur for a maximum of 2 years during the 3-year 

averaging period. Since drill rigs move to different locations during field development, it is not likely that 

a drilling operation would occur over 3 consecutive years in the same location. The yearly maximum 

eighth-highest daily maximum 1-hour NO2 concentrations for all modeled scenarios are provided in 

Appendix L of the AQTSD. 

For 24-hour PM2.5 NAAQS compliance demonstrations from well pad and access road construction, all 

modeled impacts represent the 3-year average of the maximum 24-hour concentrations from three 

separate activities, assuming well pad and access road construction occurs over 1 year, drilling operations 

occur for 1 year and well production activities occur for 1 year. Since well pad and access road 

construction would be temporary (occurring over a 5 –7 day period) and in isolation, this scenario 

represents a conservative estimate of PM2.5 concentrations in the vicinity of a well pad. The yearly 

maximum 24-hour PM2.5 concentrations for all modeled scenarios are provided in Appendix L of the 

AQTSD. 

The maximum modeled criteria pollutant impacts from any of the production activities associated with the 

Proposed Action are shown in Tables 4.5-4a and 4.5-4b. Table 4.5-4a presents the model results at the 

100-meter distance from project sources and Table 4.5-4b presents the results for the 250-meter receptor 

distance. As indicated in Tables 4.5-4a and 4.5-4b, impacts from Proposed Action production sources 

would be below the NAAQS or WAAQS, and would not exceed the PSD Class II increments. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 4-49 
CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—AIR QUALITY 

Table 4.5-4a.	 Production sources, criteria pollutant modeling results: 100-meter receptor distance, 

Proposed Action 

Scenario Pollutant Averaging 

Time 

Direct 

Modeled 

(μg/m3

) 

PSD Class II 

Increment1 

(μg/m3) 

Background 

(μg/m3

) 

Total 

Predicted 

(μg/m3

) 

WAAQS 

(μg/m3

) 

NAAQS 

(μg/m3) 

Gas Plant CO 1-hour 

8-hour 

514.1 

315.8 

n/a 

n/a 

1,026.0 

798.0 

1,540.1 

1,113.8 

40,000 

10,000 

40,000 

10,000 

Gas Plant NO2 1-hour 

Annual 

105.62

 11.9 

n/a 

25 

75.0 

9.1 

180.6 

21.0 

n/a 

100 

188 

100 

Well 

Production 

(16 well pad) 

NO2 1-hour 

Annual 

112.62

 7.3 

n/a 

25 

75.0 

9.1 

187.6 

16.4 

n/a 

100 

188 

100 

Gas Plant SO2 1-hour 

3-hour 

24-hour 

Annual 

0.63

 0.6 

0.2 

0.03 

n/a 

512 

91 

20 

19.7 

11.5 

4.2 

3.8 

20.3 

12.1 

4.4 

3.8 

n/a 

1,300 

260 

60 

196 

1,300 

365 

80 

Gas Plant PM10 24-hour 

Annual 

11.5

 1.4 

30 

17 

56.0 

13.5 

67.5 

14.9 

150 

50 

n/a 

50 

Gas Plant PM2.5 24-hour 

Annual 

7.94

 1.4 

9 

4 

9.2 

4.2 

17.1 

5.6 

n/a 

n/a 

35 

15 

1 The PSD demonstrations serve information purposes only and do not constitute a regulatory PSD increment consumption 

analysis 

2 NO2 1-hour concentrations are calculated as the 3-year average of the 8th highest daily maximum 1-hour concentrations. 

3 SO2 1-hour concentration are 4th highest daily maximum 1-hour concentration. 

4 PM2.5 24-hour concentration is calculated as the 3-year average of the highest 24-hour concentrations. 

Table 4.5-4b.	 Production sources, criteria pollutant modeling results: 250-meter receptor distance, 

Proposed Action 

Scenario Pollutant Averaging 

Time 

Direct 

Modeled 

(μg/m3

) 

PSD Class II 

Increment1 

(μg/m3) 

Background 

(μg/m3

) 

Total 

Predicted 

(μg/m3

) 

WAAQS 

(μg/m3

) 

NAAQS 

(μg/m3) 

Gas Plant CO 1-hour 

8-hour 

388.2 

236.2 

n/a 

n/a 

1,026.0 

798.0 

1,414.2 

1,034.2 

40,000 

10,000 

40,000 

10,000 

Gas Plant NO2 1-hour 

Annual 

99.52

 8.3 

n/a 

25 

75.0 

9.1 

174.5 

17.4 

n/a 

100 

188 

100 

Well 

Production 

(16 well pad) 

NO2 1-hour 

Annual 

101.42

 3.5 

n/a 

25 

75.0 

9.1 

176.4 

12.6 

n/a 

100 

188 

100 

Gas Plant SO2 1-hour 

3-hour 

24-hour 

Annual 

0.43

 0.4 

0.2 

0.02 

n/a 

512 

91 

20 

19.7 

11.5 

4.2 

3.8 

20.1 

11.9 

4.4 

3.8 

n/a 

1,300 

260 

60 

196 

1,300 

365 

80 

Gas Plant PM10 24-hour 

Annual 

7.2

 0.9 

30 

17 

56.0 

13.5 

63.2 

14.4 

150 

50 

n/a 

50 

Gas Plant PM2.5 24-hour 

Annual 

5.64

 1.4 

9 

4 

9.2 

4.2 

14.8 

5.6 

n/a 

n/a 

35 

15 

1 The PSD demonstrations serve information purposes only and do not constitute a regulatory PSD increment consumption 

analysis 

2 NO2 1-hour concentrations are calculated as the 3-year average of the 8th highest daily maximum 1-hour concentrations. 

3 SO2 1-hour concentration are 4th highest daily maximum 1-hour concentration. 

4 PM2.5 24-hour concentration is calculated as the 3-year average of the highest 24-hour concentrations. 

The maximum modeled criteria pollutant impacts from well development activities associated with the 

Proposed Action are shown in Tables 4.5-5a and 4.5-5b for both the 100-meter and 250-meter receptor 

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distances from project sources. As described earlier in this section, the 1-hour NO2 and the 24-hour PM2.5 

results are calculated as a three-year average based on modeling the Proposed Action field development 

and field production sources of air emissions. The scenarios modeled for determining air quality impacts 

from NOx emission sources included Tier 2 drill rig operation and multi-well pads with 16 wells in 

production. For PM2.5 emission sources, the scenario modeled includes the emissions from 4 single well 

pads and access roads under construction, 4 Tier 2 drill rigs operating, and 4 single wells in production. 

As indicated in Tables 4.5-5a and 4.5-5b the Proposed Action field development source emissions would 

not result in any exceedances of the NAAQS or WAAQS at the 250-meter distance. However, modeled 

impacts for the 100-meter receptor distance case did result in short-term concentrations that were 

predicted to be above the 1-hour NO2 NAAQS, the 24-hour PM2.5 NAAQS, and the 24-hour PM10 

WAAQS. 

Tables providing the individual annual modeled 8th highest daily maximum 1-hour NO2 concentrations 

and the individual annual modeled maximum 24-hour PM2.5 concentrations predicted for all modeling 

scenarios are presented in Appendix L of the AQTSD, and the results are discussed in AQTSD Section 

3.5.4. 

In order to demonstrate compliance with the NAAQS and WAAQS additional mitigation measures will 

be required through the application of one or more emission control measures, such as those described in 

Section 4.5.9 Unavoidable Adverse Impacts and Additional Mitigation could be implemented. 

Note that the emissions from field development activities would be temporary and would not consume 

PSD increment, and as a result are excluded from increment comparisons. 

Additional details on the near-field criteria pollutant modeling impact assessment are provided in Section 

3.5 of the AQTSD. 

Table 4.5-5a. Field development sources, criteria pollutant modeling results: 100-meter receptor 

distance, Proposed Action 

Scenario Pollutant Averaging 

Time 

Direct 

Modeled 

(μg/m3

) 

Background 

(μg/m3) 

Total 

Predicted 

(μg/m3) 

WAAQS 

(μg/m3) 

NAAQS 

(μg/m3) 

4 Tier 2 Drill Rigs CO 1-hour 

8-hour 

626.8 

380.1 

1,026.0 

798.0 

1,652.8 

1,178.1 

40,000 

10,000 

40,000 

10,000 

16 Well Pad, Tier 2 

Drill Rig 

NO2 1-hour 

Annual 

123.51

 23.7 

75.0 

9.1 

198.5 

32.8 

n/a 

100 

188 

100 

4, 4-Well Pads, 4 

Tier 2 Drill Rigs 

NO2 1-hour 

Annual 

125.61

 25.6 

75.0 

9.1 

200.6 

34.7 

n/a 

100 

188 

100 

4 Tier 2 Drill Rigs SO2 1-hour 

3-hour 

24-hour 

Annual 

27.62

 17.5 

9.9 

1.4 

19.7 

11.5 

4.2 

3.8 

47.3 

29.0 

14.1 

5.2 

n/a 

1,300 

260 

60 

196 

1,300 

365 

80 

4 Tier 2 Drill Rigs CO 1-hour 

8-hour 

626.8 

380.1 

1,026.0 

798.0 

1,652.8 

1,178.1 

40,000 

10,000 

40,000 

10,000 

Single Well Pad 

and Access Road 

Construction 

PM10 24-hour 

Annual 

123.2

 7.5 

56.0 

13.5 

179.2 

21.0 

150 

50 

n/a 

50 

PM2.5 24-hour 

Annual 

31.43

 4.8 

9.2 

4.2 

40.6 

9.0 

n/a 

n/a 

35 

15 

1	 NO2 1-hour concentrations are calculated as the 3-year average of the 8th highest daily maximum 1-hour concentrations. (16 well 

pad case includes 2 years of drill rig operation concurrent with 15 wells in production, and 1 year with 16 wells in production, 4, 

4-well pad case includes 1 year with 4 drill rigs in operation and 2 years with 2 drill rigs in operation and 8 wells in production) 

2 SO2 1-hour concentration are 4th highest daily maximum 1-hour concentration. 

3 PM2.5 24-hour concentration calculated using 3-year average of the maximum modeled 24-hour concentrations (includes well pad 

and access road construction, tier 2 drill rig operation, and well production activities) 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 4-51 
CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—AIR QUALITY 

Table 4.5-5b.	 Field development sources, criteria pollutant modeling results: 250-meter receptor 

distance, Proposed Action 

Scenario Pollutant Averaging 

Time 

Direct 

Modeled 

(μg/m3

) 

Background 

(μg/m3

) 

Total 

Predicted 

(μg/m3

) 

WAAQS 

(μg/m3

) 

NAAQS 

(μg/m3) 

4 Tier 2 Drill Rigs CO 1-hour 

8-hour 

308.6 

131.0 

1,026.0 

798.0 

1,334.6 

929.0 

40,000 

10,000 

40,000 

10,000 

16 Well Pad, Tier 2 

Drill Rig 

NO2 1-hour 

Annual 

102.01

 12.0 

75.0 

9.1 

177.0 

21.1 

n/a 

100 

188 

100 

4, 4-Well Pads, 4 Tier 

2 Drill Rigs 

NO2 1-hour 

Annual 

101.11

 14.8 

75.0 

9.1 

176.1 

23.9 

n/a 

100 

188 

100 

4 Tier 2 Drill Rigs SO2 1-hour 

3-hour 

24-hour 

Annual 

14.82

 8.2 

3.1 

0.5 

19.7 

11.5 

4.2 

3.8 

34.5 

19.7 

7.3 

4.3 

n/a 

1,300 

260 

60 

196 

1,300 

365 

80 

4 Tier 2 Drill Rigs CO 1-hour 

8-hour 

308.6 

131.0 

1,026.0 

798.0 

1,334.6 

929.0 

40,000 

10,000 

40,000 

10,000 

Single Well Pad and 

Access Road 

Construction 

PM10 24-hour 

Annual 

76.2

 3.0 

56.0 

13.5 

132.3 

16.5 

150 

50 

n/a 

50 

PM2.5 24-hour 

Annual 

23.73

 2.4 

9.2 

4.2 

32.9 

6.6 

n/a 

n/a 

35 

15 

1	 NO2 1-hour concentrations are calculated as the 3-year average of the 8th highest daily maximum 1-hour concentrations. (16 well 

pad case includes 2 years of drill rig operation concurrent with 15 wells in production, and 1 year with 16 wells in production, 4, 

4-well pad case includes 1 year with 4 drill rigs in operation and 2 years with 2 drill rigs in operation and 8 wells in production) 

2 SO2 1-hour concentration are 4th highest daily maximum 1-hour concentration. 

3 PM2.5 24-hour concentration calculated using 3-year average of the maximum modeled 24-hour concentrations (includes well pad 

and access road construction, tier 2 drill rig operation, and well production activities) 

The maximum predicted acute and chronic (long-term) HAP impacts from production activities compared 

with applicable REL and RfC exposure thresholds are shown in Tables 4.5-6 through 4.5-7. Tables 4.5-

6a and 4.5-6b present the acute impacts for both and 100-meter and 250-meter receptor distances, and 

Tables 4.5-7a and 4.5-7b present the long-term impacts for both receptor distances. As indicated in these 

tables, HAP emissions resulting for Proposed Action production activities would result in impacts that are 

below the HAP threshold exposure levels. 

Table 4.5-6a. Production sources, maximum long-term (1-hour) HAP modeling results: 100-meter 

receptor distance, Proposed Action 

Modeling Scenario HAP Modeled Concentration 

(μg/m3

) 

REL or IDLH 

(μg/m3) 

16 Well Pad Production Benzene 6.2 1,3001 

16 Well Pad Production Toluene 8.4 37,0001 

16 Well Pad Production Ethylbenzene 0.2 350,0002 

16 Well Pad Production Xylene 3.8 22,0001 

16 Well Pad Production n-Hexane 33.6 390,0002 

16 Well Pad Production Formaldehyde 47.3 551 

Gas Plant Formaldehyde 5.8 551 

1 Reference Exposure Level 

2 Immediately Dangerous to Life or Health value divided by 10.
 

4-52 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—AIR QUALITY 

Table 4.5-6b. Production sources, maximum long-term (1-hour) HAP modeling results: 250-meter 

receptor distance, Proposed Action 

Modeling Scenario HAP Modeled Concentration 

(μg/m3

) 

REL or IDLH 

(μg/m3) 

16 Well Pad Production Benzene 5.5 1,3001 

16 Well Pad Production Toluene 7.4 37,0001 

16 Well Pad Production Ethylbenzene 0.2 350,0002 

16 Well Pad Production Xylene 3.2 22,0001 

16 Well Pad Production n-Hexane 29.6 390,0002 

16 Well Pad Production Formaldehyde 41.6 551 

Gas Plant Formaldehyde 5.3 551 

1 Reference Exposure Level 

2 Immediately Dangerous to Life or Health value divided by 10.
 

Table 4.5-7a. Production sources, maximum long-term (annual) HAP modeling results: 100-meter 

receptor distance, Proposed Action 

Modeling Scenario HAP 

Modeled Concentration 

(μg/m3) 

Non-carcinogenic RfC 

(μg/m3

) 

16 Well Pad Production Benzene 0.2 30 

16 Well Pad Production Toluene 0.3 5,000 

16 Well Pad Production Ethylbenzene 0.01 1,000 

16 Well Pad Production Xylene 0.1 100 

16 Well Pad Production n-Hexane 1.2 700 

16 Well Pad Production Formaldehyde 1.7 9.8 

Gas Plant Formaldehyde 0.4 9.8 

Table 4.5-7b. Production sources, maximum long-term (annual) HAP modeling results: 250-meter 

receptor distance, Proposed Action 

Modeling Scenario HAP Modeled Concentration 

(μg/m3) 

Non-carcinogenic RfC 

(μg/m3) 

16 Well Pad Production Benzene 0.1 30 

16 Well Pad Production Toluene 0.1 5,000 

16 Well Pad Production Ethylbenzene 0.003 1,000 

16 Well Pad Production Xylene 0.06 100 

16 Well Pad Production n-Hexane 0.6 700 

16 Well Pad Production Formaldehyde 0.8 9.8 

Gas Plant Formaldehyde 0.4 9.8 

Two estimates of cancer risk were made: one that corresponds to most-likely-exposure (MLE) over a 

national residency average of 9 years with some time spent away from home, and one reflective of the 

maximally-exposed-individual (MEI) residing at one location for a lifetime with no time spent away from 

home. The cancer risks for all constituents were then summed to provide an estimate of the total 

inhalation cancer risk. 

Near-field modeling was also performed to estimate the long-term risk, for both the most-likely-exposure 

(MLE) and maximally-exposed-individual (MEI) scenarios, from benzene, ethyl benzene, and 

formaldehyde emissions resulting from production activities. Table 4.5-8 presents the cancer risk 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 4-53 
 

CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—AIR QUALITY
 

estimates for the proposed compression and gas plant facilities, for both the 100-meter and 250-meter 

receptor cases, and at the distance required to be below a one-in-one-million cancer risk level for either 

the MLE or MEI analysis. The modeling results indicate that for the MLE analysis the cancer risk is 

below one-in-one-million at the 100-meter distance for both the proposed compression and gas plant 

facilities. For the MEI analysis the distance where the cancer risk would fall below a one-in-one-million 

cancer risk level is 0.25 miles for the proposed compression facility, and 1.0 miles for the proposed gas 

plant. Note that the risk estimates for the compression and gas plant facilities only considered 

formaldehyde emissions, since benzene and ethyl benzene emissions for these facilities would be 

negligible. 

Table 4.5-8. Long-term modeled formaldehyde MLE and MEI cancer risk analyses for proposed 

compression and gas plant, Proposed Action 

Modeling 

Scenario 

Receptor 

Distance Analysis 

Modeled 

Concentration 

(μg/m3

) 

Unit Risk Factor 

1/(μg/m3

) 

Exposure 

Adjustment 

Factor 

Cancer 

Risk 

Compression 100 meters MLE 0.19 1.3 x 10-5 0.0949 0.2 x 10-6 

Compression 100 meters MEI 0.19 1.3 x 10-5 0.86 2.1 x 10-6 

Gas Plant 100 meters MLE 0.36 1.3 x 10-5 0.0949 0.4 x 10-6 

Gas Plant 100 meters MEI 0.36 1.3 x 10-5 0.86 4.0 x 10-6 

Compression 250 meters MLE 0.14 1.3 x 10-5 0.0949 0.2 x 10-6 

Compression 250 meters MEI 0.14 1.3 x 10-5 0.86 1.6 x 10-6 

Gas Plant 250 meters MLE 0.36 1.3 x 10-5 0.0949 0.4 x 10-6 

Gas Plant 250 meters MEI 0.36 1.3 x 10-5 0.86 4.0 x 10-6 

Compression 0.25 miles MLE 0.08 1.3 x 10-5 0.0949 0.1 x 10-6 

Compression 0.25 miles MEI 0.08 1.3 x 10-5 0.86 0.9 x 10-6 

Gas Plant 1.0 miles MLE 0.08 1.3 x 10-5 0.0949 0.1 x 10-6 

Gas Plant 1.0 miles MEI 0.08 1.3 x 10-5 0.86 0.9 x 10-6 

Table 4.5-9 presents the cancer risk estimates for a multi-well pad, with 16 wells in production, for both 

the 100-meter and 250-meter receptor cases, and at the distance required to be below a one-in-one-million 

cancer risk level for either the MLE or MEI analysis. The modeling results indicate that for the MLE 

analysis the cancer risk is one-in-one-million at the 250-meter distance. For the MEI analysis the distance 

where the cancer risk would fall below a one-in-one-million cancer risk level is 1.25 miles. Mitigation 

measures for NOx emissions that will be required to demonstrate compliance with the 1-hour NO2 

NAAQS will also decrease the predicted cancer risk impact for formaldehyde (see Section 4.5.9 

Unavoidable Adverse Impacts and Additional Mitigation). 

Additional details on the near-field HAP modeling impact assessment are provided in Section 3.6 of the 

AQTSD. 

4-54 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
 

 

 

 

 

 

 

 

 

 

 

 

 

1 

CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—AIR QUALITY 

Table 4.5-9.	 Long-term modeled MLE and MEI cancer risk analyses for production well case: 16 wells, 

1 multi-well pad, Proposed Action 

Receptor 

Distance Analysis HAP 

Constituent 

Modeled 

Concentration 

(μg/m3

) 

Unit Risk Factor 

1/(μg/m3) 

Exposure 

Adjustment Factor 

Cancer 

Risk 

100 meters MLE Benzene 0.23 7.8 x 10-6 0.0949 0.2 x 10-6 

Ethyl Benzene 0.007 2.5 x 10-6 0.0949 0.001 x 10-6 

Formaldehyde 1.7 1.3 x 10-5 0.0949 2.1 x 10-6 

Total Combined1 2.3 x 10-6 

100 meters MEI Benzene 0.23 7.8 x 10-6 0.86 1.5 x 10-6 

Ethyl Benzene 0.007 2.5 x 10-6 0.86 0.01 x 10-6 

Formaldehyde 1.7 1.3 x 10-5 0.86 19.1 x 10-6 

Total Combined1 20.7 x 10-6 

250 meters MLE Benzene 0.10 7.8 x 10-6 0.0949 0.08 x 10-6 

Ethyl Benzene 0.003 2.5 x 10-6 0.0949 0.001 x 10-6 

Formaldehyde 0.79 1.3 x 10-5 0.0949 1.0 x 10-6 

Total Combined1 1.0 x 10-6 

250 meters MEI Benzene 0.10 7.8 x 10-6 0.86 0.7 x 10-6 

Ethyl Benzene 0.003 2.5 x 10-6 0.86 0.006 x 10-6 

Formaldehyde 0.79 1.3 x 10-5 0.86 8.8 x 10-6 

Total Combined1 9.5 x 10-6 

1.25 miles MLE Benzene 0.01 7.8 x 10-6 0.0949 0.008 x 10-6 

Ethyl Benzene 0.0003 2.5 x 10-6 0.0949 0.00001 x 10-6 

Formaldehyde 0.08 1.3 x 10-5 0.0949 0.09 x 10-6 

Total Combined1 0.1 x 10-6 

1.25 miles MEI Benzene 0.01 7.8 x 10-6 0.86 0.07 x 10-6 

Ethyl Benzene 0.0003 2.5 x 10-6 0.86 0.001 x 10-6 

Formaldehyde 0.08 1.3 x 10-5 0.86 0.9 x 10-6 

Total Combined1 0.9 x 10-6 

Total risk is calculated here; however, the additive effects of multiple chemicals are not fully understood and this should be taken 

into account when viewing these results. 

Far-Field Modeling 

Far-field modeling using the CAMx model was performed to quantify potential air quality impacts to both 

ambient air concentrations and AQRVs from air pollutant emissions of NOx, SO2, PM10, PM2.5, VOC, and 

CO expected to result from the development of the Proposed Action as well as the combined effects of the 

CD-C project and other new sources of emissions in the region. Key results of the analysis of the air 

quality and AQRV impacts of the Proposed Action are described below. Additional detail is provided in 

Section 4.5 of the AQTSD. 

Criteria Pollutants Including Ozone 

The results of the far-field modeling showed that the Proposed Action would make no significant 

contribution to modeled exceedances of the NAAQS, WAAQS or Colorado Ambient Air Quality 

Standards (CAAQS) for ozone (see AQTSD Section 4.5.4) or any other criteria pollutant (see AQTSD 

Section 4.5.3). 

The Proposed Action source contribution to future year ozone formation was assessed using two methods: 

the EPA’s Modeled Attainment Test Software (MATS; Abt, 2009) and absolute modeled concentrations. 

The MATS-estimated Proposed Action maximum impact on future year 8-hour average ozone 

concentrations would be less than or equal to 0.8 ppb. The two-year approximation to future-year 8-hour 

average ozone concentrations estimated using absolute CAMx model concentrations shows the Proposed 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 4-55 
 

 

CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—AIR QUALITY
 

Action maximum ozone impact would be 1.6 ppb or less. For both the absolute modeled concentration 

and MATS results, the largest ozone impacts due to the Proposed Action emissions were in the vicinity of 

the CD-C project area. In Sublette County, where the only MATS-projected exceedances of the 75 ppb 

NAAQS within the study area would occur, ozone impacts due to the Proposed Action were extremely 

small, and were less than or equal to 0.04 ppb. The highest CD-C ozone contributions to ozone in the 

study area occurred on days when regional 8-hour ozone would be low (<60ppb). 

PSD increments were not exceeded at any Class I or sensitive Class II area within the study area. 

Mid-Field Impacts 

CAMx estimated criteria pollutant impacts from Proposed Action sources and from Proposed Action 

sources and regional sources, within and near the CD-C project area are shown in Table 4.5-10. As 

indicated in Table 4.5-10 the cumulative impacts resulting from project and regional sources would be 

below the applicable ambient air quality standards and the direct project impacts would be below the PSD 

Class II Increments. 

Table 4.5-10. Mid-Field criteria pollutant modeling results, Proposed Action 

Pollutant Averaging 

Time 

Modeled 

Concentration 

from CD-C 

Project Sources 

(μg/m3

) 

Modeled 

Concentration 

from All 

Sources 

(μg/m3) 

PSD Class II 

Increment1 

(μg/m3

) 

WAAQS 

(μg/m3

) 

NAAQS 

(μg/m3) 

CO4 1-hour 

8-hour 

--

--

491.3 

357.0 

n/a 

n/a 

40,000 

10,000 

40,000 

10,000 

NO2 1-hour 

Annual 

47.1 

6.6 

81.42 

17.1 

n/a 

25 

n/a 

100 

188 

100 

O3 8-hour 4.3 142.4 n/a 147 147 

SO2 1-hour 

3-hour 

24-hour 

Annual 

0.02 

0.02 

0.01 

0.003 

30.83 

30.0 

11.3 

3.1 

n/a 

512 

91 

20 

n/a 

1,300 

260 

60 

196 

1,300 

365 

80 

PM10 24-hour 

Annual 

7.3 

2.5 

55.8 

7.5 

30 

17 

150 

50 

n/a 

50 

PM2.5 24-hour 

Annual 

2.4 

0.6 

18.7 

3.8 

9 

4 

n/a 

n/a 

35 

15 

1 The PSD demonstrations serve information purposes only and do not constitute a regulatory PSD increment consumption 

analysis 2 NO2 1-hour concentration is 8th highest daily maximum 1-hour concentration. Value includes contribution from NO. 3 SO2 1-hour concentration is 4th highest daily maximum 1-hour concentration. 4 No value is given for the CD-C project CO concentration contribution because the CAMx source apportionment tool does not 

track CO. 

AQRV Impacts 

Visibility Impacts. Visibility impacts estimated using the FLAG 2010 method at Class I and sensitive 

Class II areas resulting from Proposed Action source emissions are shown in Table 4.5-11. An additional 

method (BLM method) was used to evaluate visibility impacts and the results are presented in the 

AQTSD, Section 4.6.1. 

The visibility analysis indicated a maximum of 5 days with CD-C project emissions resulting in impacts 

greater than the 0.5 delta-deciviews (Δdv) threshold at any of the Class I and sensitive Class II areas 

analyzed for both the 2005 and 2006 meteorological data. Using the 98th percentile or eighth-highest 

value as a threshold (as recommended in the FLAG 2010 document) there would be zero days above the 

0.5 Δdv threshold at any of the Class I or sensitive Class II areas. 

4-56 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
 

CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—AIR QUALITY 

Table 4.5-11. Visibility impacts using FLAG 2010 screening method, Proposed Action 

Class I or Sensitive Class II Area Number of Days > 

0.5 Δdv Maximum Δdv 98th Percentile 

Maximum Δdv 

Bridger Wilderness Area 0 0.20 0.03 

Fitzpatrick Wilderness Area 0 0.16 0.03 

Savage Run Wilderness Area 1 0.61 0.20 

Mount Zirkel Wilderness Area 1 0.65 0.24 

Rawah Wilderness Area 0 0.24 0.12 

Popo Agie Wilderness Area 0 0.22 0.03 

Wind River Roadless Area 0 0.14 0.04 

Dinosaur National Monument 5 0.85 0.34 

Deposition Impacts 

Modeling results for Proposed Action source emissions indicated that there were no nitrogen or sulfur 

deposition impacts that exceeded the BLM critical load values at any Class I/sensitive Class II area; 

however, the deposition analysis threshold (DAT) for nitrogen was exceeded at several Class I areas 

near/downwind of CD-C project area. Deposition impacts are summarized in Section 4.6.2 of the 

AQTSD. 

Acidification at Sensitive Lakes. Modeling results for Proposed Action sources indicated that there would 

be no ANC changes at any of the 12 analyzed lakes that exceeded the 10-percent threshold or the 

ΔANC<1 μeq/L threshold for the two extremely sensitive lakes. Lake ANC impacts are summarized in 

Section 4.6.3 of the AQTSD. 

Regional Climate Change and Greenhouse Gas Emissions 

The current scientific consensus is that the warming of the climate system is “unequivocal” and 

“continued greenhouse gas emissions at or above current rates would cause further warming and induce 

many changes in the global climate system during the 21st century that would very likely be larger than 

those observed during the 20th century.” (IPCC, 2007). Specific regional effects of climate change are 

highly uncertain (see section 3.5 Air Quality), but may include extreme weather, adverse health impacts 

due to increased intensity and duration of heat waves, and seasonally decreasing water supplies that 

exacerbate competition for over-allocated water resources. As discussed in Chapter 3, it is not possible to 

attribute emissions of GHGs from any particular source as having a specific climate impact, globally or 

regionally, due to the longevity of GHGs in the atmosphere. GHG emissions from all sources contribute 

to increased incremental concentrations in the earth’s atmosphere and to the global climate response. 

The maximum greenhouse gas emissions resulting from the Proposed Action source emissions are 

estimated at 5.2 tg/yr of CO2 equivalent emissions. The CD-C project’s peak CO2 equivalent emissions 

year is 2022, in which the combined emissions from new Proposed Action sources and existing sources 

would be approximately 10 tg/year. To place the CD-C project’s GHG emissions in context, the GHG 

emissions from the top four emitting coal-fired power plants in Wyoming range from 3-15 tg/year (data 

from <http://epa.gov/-climatechange/emissions/ghgdata/2010data.html>). CD-C project GHGs would be 

comparable to the total GHG emissions from the City of San Francisco (10 tg/year; 

<http://www.sfenvironment.org/-downloads/library/climateactionplan.pdf>) during the year 2000). 

4.5.7.2 Alternative A: 100-Percent Vertical Drilling 

Alternative A includes the construction and operation of 8,950 natural gas wells, associated roads, and 

production facilities, including compression and gas processing facilities. All the proposed natural gas 

wells would be drilled conventionally, with a single vertical well bore on each well pad. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 4-57 
 

CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—AIR QUALITY
 

Near-Field Modeling 

The maximum modeled criteria pollutant impacts from any of the production activities associated with 

Alternative A production facilities would be similar to the Proposed Action; however, pollutant impacts 

from individual well sites would be less given the wells would be drilled on single well pads. The impacts 

for Alternative A production facilities are shown in Tables 4.5-12a and 4.5-12b. As indicated in these 

tables, impacts from Alternative A production sources would be below the NAAQS or WAAQS, and 

would not exceed the PSD Class II increments. 

Table 4.5-12a. Production sources, criteria pollutant modeling results: 100-meter receptor distance, 

Alternative A 

Scenario Pollutant Averaging 

Time 

Direct 

Modeled 

(μg/m3

) 

PSD Class 

II 

Increment1 

(μg/m3) 

Background 

(μg/m3

) 

Total 

Predicted 

(μg/m3

) 

WAAQS 

(μg/m3

) 

NAAQS 

(μg/m3) 

Gas Plant CO 1-hour 

8-hour 

514.1 

315.8 

n/a 

n/a 

1,026.0 

798.0 

1,540.1 

1,113.8 

40,000 

10,000 

40,000 

10,000 

Gas Plant NO2 

1-hour 

Annual 

105.62

 11.9 

n/a 

25 

75.0 

9.1 

180.6 

21.0 

n/a 

100 

188 

100 

Single well 

pad 

production 

NO2 

1-hour 

Annual 

18.12

 0.9 

n/a 

25 

75.0 

9.1 

93.1 

10.0 

n/a 

100 

188 

100 

Gas Plant SO2 

1-hour 

3-hour 

24-hour 

Annual 

0.63

 0.6 

0.2 

0.03 

n/a 

512 

91 

20 

19.7 

11.5 

4.2 

3.8 

20.3 

12.1 

4.4 

3.8 

n/a 

1,300 

260 

60 

196 

1,300 

365 

80 

Gas Plant PM10 

24-hour 

Annual 

11.5

 1.4 

30 

17 

56.0 

13.5 

67.5 

14.9 

150 

50 

n/a 

50 

Gas Plant PM2.5 

24-hour 

Annual 

7.9

 1.4 

9 

4 

9.2 

4.2 

17.1 

5.6 

n/a 

n/a 

35 

15 

1	 The PSD demonstrations serve information purposes only and do not constitute a regulatory PSD increment consumption 

analysis 

2 NO2 1-hour concentrations are calculated as the 3-year average of the 8th highest daily maximum 1-hour concentrations. (The 

yearly maximum 8th highest daily maximum 1-hour NO2 concentrations for all modeled scenarios are provided in Appendix L of 

the AQTSD). 

3 SO2 1-hour concentration are 4th highest daily maximum 1-hour concentration. 

4-58 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
 

CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—AIR QUALITY 

Table 4.5-12b. Production sources, criteria pollutant modeling results: 250-meter receptor distance, 

Alternative A 

Scenario Pollutant Averaging 

Time 

Direct 

Modeled 

(μg/m3

) 

PSD Class 

II 

Increment1 

(μg/m3) 

Background 

(μg/m3

) 

Total 

Predicted 

(μg/m3

) 

WAAQS 

(μg/m3

) 

NAAQS 

(μg/m3) 

Gas Plant CO 1-hour 

8-hour 

388.2 

236.2 

n/a 

n/a 

1,026.0 

798.0 

1,414.2 

1,034.2 

40,000 

10,000 

40,000 

10,000 

Gas Plant NO2 

1-hour 

Annual 

99.52

 8.3 

n/a 

25 

75.0 

9.1 

174.5 

17.4 

n/a 

100 

188 

100 

Single well 

pad 

production 

NO2 

1-hour 

Annual 

12.02

 0.4 

n/a 

25 

75.0 

9.1 

87.0 

9.5 

n/a 

100 

188 

100 

Gas Plant SO2 

1-hour 

3-hour 

24-hour 

Annual 

0.43

 0.4 

0.2 

0.02 

n/a 

512 

91 

20 

19.7 

11.5 

4.2 

3.8 

20.1 

11.9 

4.4 

3.8 

n/a 

1,300 

260 

60 

196 

1,300 

365 

80 

Gas Plant PM10 

24-hour 

Annual 

7.2

 0.9 

30 

17 

56.0 

13.5 

63.2 

14.4 

150 

50 

n/a 

50 

Gas Plant PM2.5 

24-hour 

Annual 

5.64

 1.4 

9 

4 

9.2 

4.2 

14.8 

5.6 

n/a 

n/a 

35 

15 

1	 The PSD demonstrations serve information purposes only and do not constitute a regulatory PSD increment consumption 

analysis 

2 NO2 1-hour concentrations are calculated as the 3-year average of the 8th highest daily maximum 1-hour concentrations. (The 

yearly maximum 8th highest daily maximum 1-hour NO2 concentrations for all modeled scenarios are provided in Appendix L of 

the AQTSD). 

3 SO2 1-hour concentration are 4th highest daily maximum 1-hour concentration. 

The maximum modeled criteria pollutant impacts from well development activities associated with 

Alternative A would differ slightly from the Proposed Action, given Alternative A is a vertical well 

drilling alternative. The maximum modeled criteria pollutant impacts from well development activities 

are shown in Tables 4.5-13a and 4.5-13b for both the 100-meter and 250-meter receptor distances from 

project sources. As described in Section 4.5.7,1 the 1-hour NO2 and the 24-hour PM2.5 results are 

calculated as a three-year average based on modeling Alternative A field development and field 

production sources of air emissions. The scenarios used for modeling air quality impacts from NOx 

emission sources included Tier 2 drill rig operation and single wells in production. For PM2.5 emission 

sources, the scenario modeled includes the emissions from a 4 single-well pads and access roads under 

construction, 4 Tier 2 drill rigs operating, and 4 single wells in production. As indicated in Tables 4.5-13a 

and 4.5-13b, Alternative A field development source emissions would not result in any exceedances of 

the NAAQS or WAAQS at the 250-meter distance. However, modeled impacts for the 100-meter receptor 

distance case did result in short-term concentrations that were predicted to be above the 1-hour NO2 

NAAQS, the 24-hour PM2.5 NAAQS, and the 24-hour PM10 WAAQS. 

Tables providing the individual annual modeled 8th highest daily maximum 1-hour NO2 concentrations 

and the individual annual modeled maximum 24-hour PM2.5 concentrations predicted for all modeling 

scenarios are presented in Appendix L of the AQTSD, and the results are discussed in AQTSD Section 

3.5.4. 

In order to demonstrate compliance with the NAAQS and WAAQS, additional mitigation measures will 

be required through application of one or more emission control measures, such as those described in 

Section 4.5.9 Unavoidable Adverse Impacts and Additional Mitigation. 

Note that the emissions from field development activities are temporary and do not consume PSD 

increment, and as a result are excluded from increment comparisons. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 4-59 
CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—AIR QUALITY 

Additional detail on near-field modeling methods and results is provided in Section 3.5 of the AQTSD. 

Table 4.5-13a. Field development sources, criteria pollutant modeling results: 100-meter receptor 

distance, Alternative A 

Scenario Pollutant Averaging 

Time 

Direct 

Modeled 

(μg/m3

) 

Background 

(μg/m3

) 

Total 

Predicted 

(μg/m3

) 

WAAQS 

(μg/m3

) 

NAAQS 

(μg/m3) 

4 Tier 2 Drill Rigs CO 1-hour 

8-hour 

626.8 

380.1 

1,026.0 

798.0 

1,652.8 

1,178.1 

40,000 

10,000 

40,000 

10,000 

Single Well Pad, 

Tier 2 Drill Rig NO2 

1-hour 

Annual 

105.41

 25.1 

75.0 

9.1 

180.4 

34.2 

n/a 

100 

188 

100 

4, Single Well 

Pads, 4 Tier 2 Drill 

Rigs 

NO2 

1-hour 

Annual 

133.61

 27.3 

75.0 

9.1 

208.6 

36.4 

n/a 

100 

188 

100 

4 Tier 2 Drill Rigs SO2 

1-hour 

3-hour 

24-hour 

Annual 

27.62

 17.5 

9.9 

1.4 

19.7 

11.5 

4.2 

3.8 

47.3 

29.0 

14.1 

5.2 

n/a 

1,300 

260 

60 

196 

1,300 

365 

80 

4 Tier 2 Drill Rigs CO 1-hour 

8-hour 

626.8 

380.1 

1,026.0 

798.0 

1,652.8 

1,178.1 

40,000 

10,000 

40,000 

10,000 

Single Well Pad 

and Access Road 

Construction 

PM10 

24-hour 

Annual 

123.2

 7.5 

56.0 

13.5 

179.2 

21.0 

150 

50 

n/a 

50

 PM2.5 

24-hour 

Annual 

31.43

 4.8 

9.2 

4.2 

40.6 

9.0 

n/a 

n/a 

35 

15 

1	 NO2 1-hour concentrations are calculated as the 3-year average of the 8th highest daily maximum 1-hour concentrations. (Single 

well pad case includes 2 years of drill rig operation concurrent with 4 wells in production, and 1 year with 5 wells in production),4, 

single-well pad case includes 1 year with 4 drill rigs in operation and 2 years with 2 drill rigs in operation and 2 wells in 

production). (The yearly maximum 8th highest daily maximum 1-hour NO2 concentrations for all modeled scenarios are provided 

in Appendix L of the AQTSD). 

2 SO2 1-hour concentration are 4th highest daily maximum 1-hour concentration. 

3 PM2.5 24-hour concentration calculated using 3-year average of the maximum modeled 24-hour concentrations (includes well pad 

and access road construction, tier 2 drill rig operation, and well production activities). The yearly maximum 24-hour PM2.5 

concentrations for all modeled scenarios are provided in Appendix L of the AQTSD. 

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Table 4.5-13b. Field development sources, criteria pollutant modeling results: 250-meter receptor 

distance, Alternative A 

Scenario Pollutant Averaging 

Time 

Direct 

Modeled 

(μg/m3

) 

Background 

(μg/m3

) 

Total 

Predicted 

(μg/m3

) 

WAAQS 

(μg/m3

) 

NAAQS 

(μg/m3) 

4 Tier 2 Drill Rigs CO 1-hour 

8-hour 

308.6 

131.0 

1,026.0 

798.0 

1,334.6 

929.0 

40,000 

10,000 

40,000 

10,000 

Single Well Pad, 

Tier 2 Drill Rig NO2 

1-hour 

Annual 

78.01

 13.3 

75.0 

9.1 

153.0 

22.4 

n/a 

100 

188 

100 

4, Single Well 

Pads, 4 Tier 2 Drill 

Rigs 

NO2 

1-hour 

Annual 

101.51

 15.8 

75.0 

9.1 

176.5 

24.9 

n/a 

100 

188 

100 

4 Tier 2 Drill Rigs SO2 

1-hour 

3-hour 

24-hour 

Annual 

14.82

 8.2 

3.1 

0.5 

19.7 

11.5 

4.2 

3.8 

34.5 

19.7 

7.3 

4.3 

n/a 

1,300 

260 

60 

196 

1,300 

365 

80 

Single Well Pad 

and Access Road 

Construction 

PM10 

24-hour 

Annual 

76.2

 3.0 

56.0 

13.5 

132.3 

16.5 

150 

50 

n/a 

50

 PM2.5 

24-hour 

Annual 

23.73

 2.4 

9.2 

4.2 

32.9 

6.6 

n/a 

n/a 

35 

15 

1	 NO2 1-hour concentrations are calculated as the 3-year average of the 8th highest daily maximum 1-hour concentrations. (Single 

well pad case includes 2 years of drill rig operation concurrent with 4 wells in production, and 1 year with 5 wells in production), 4, 

single-well pad case includes 1 year with 4 drill rigs in operation and 2 years with 2 drill rigs in operation and 2 wells in 

production). (The yearly maximum 8th highest daily maximum 1-hour NO2 concentrations for all modeled scenarios are provided 

in Appendix L of the AQTSD). 

2 SO2 1-hour concentration are 4th highest daily maximum 1-hour concentration. 

3 PM2.5 24-hour concentration calculated using 3-year average of the maximum modeled 24-hour concentrations (includes well pad 

andaccess road construction, tier 2 drill rig operation, and well production activities). The yearly maximum 24-hour PM2.5 

concentrations for all modeled scenarios are provided in Appendix L of the AQTSD. 

The maximum predicted acute and chronic (long-term) HAP impacts from well site production would be 

less than the impacts presented in Section 4.5.4 for the Proposed Action since there would be no multiwell pads developed. HAP impacts for the proposed compression and gas plant facilities would be the 

same as the Proposed Action. HAP impacts under Alternative A would be below all applicable REL and 

RfC exposure thresholds. For the suspected carcinogens (benzene, ethyl benzene, and formaldehyde) the 

maximum distance required to be below a one-in-one-million cancer risk level for production activities 

for either the MLE or MEI analysis would be 1.0 miles as a result of the gas plant emissions. Mitigation 

measures for NOx emissions that will be required to demonstrate compliance with the 1-hour NO2 

NAAQS will also decrease the predicted cancer risk impact associated with formaldehyde (see Section 

4.5.9 Unavoidable Adverse Impacts and Additional Mitigation). 

Far-Field Modeling 

Criteria Pollutants Including Ozone. Criteria pollutant impacts would be similar to those for the Proposed 

Action. Alternative A sources would not contribute to modeled exceedances of the NAAQS, WAAQS, or 

CAAQS for ozone or any other criteria pollutant. PSD increments would not be exceeded at any Class I 

or sensitive Class II areas. 

Mid-Field Impacts 

Alternative A criteria pollutant impacts from project sources and regional sources, within and near the 

CD-C project area, would be similar to the results shown in Table 4.5-10 for the Proposed Action. The 

cumulative impacts resulting from project and regional sources would be below the applicable ambient air 

quality standards and the direct project impacts would be below the PSD Class II Increments. 

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AQRV Impacts 

Visibility Impacts. Visibility impacts estimated using the FLAG 2010 method at Class I and sensitive 

Class II areas resulting from Alternative A emissions would be the similar to those presented in Table 

4.5-11 for the Proposed Action. 

Deposition Impacts. Nitrogen and sulfur deposition impacts under Alternative A would be similar to the 

impacts for the Proposed Action. 

Acidification at Sensitive Lakes. Potential sensitive lake acidification resulting from nitrogen and sulfur 

deposition impacts under Alternative A would be similar to the impacts for the Proposed Action, where 

modeling results indicated that there would be no ANC changes at any of the analyzed lakes that 

exceeded threshold values. 

Regional Climate Change and Greenhouse Gas Emissions 

The maximum greenhouse gas emissions resulting from Alternative A sources would be comparable to 

the emissions estimated for the Proposed Action. 

4.5.7.3 Alternative B: Enhanced Resource Protection 

Alternative B includes the construction and operation of 8,950 natural gas wells, associated roads and 

production facilities, including compression and gas processing facilities. The proposed natural gas wells 

would be drilled using a combination of vertical and directional drilling techniques. 

Near-Field Modeling 

Near-field modeling impacts for Alternative B would be similar to those presented in Section 4.5.4 for the 

Proposed Action. Impacts from Alternative B production sources would be below the NAAQS or 

WAAQS, and would not exceed the PSD Class II increments. 

Alternative B field development source emissions would not result in any exceedances of the NAAQS or 

WAAQS at the 250-meter distance; however, modeled impacts for the 100-meter receptor distance case 

did result in short-term concentrations that were predicted to be above the 1-hour NO2 NAAQS, the 24­

hour PM2.5 NAAQS, and the 24-hour PM10 WAAQS. In order to demonstrate compliance with the 

NAAQS and WAAQS, additional mitigation measures will be required through application of one or 

more emission control measures, such as those described in Section 4.5.9 Additional Mitigation. 

The maximum predicted acute and chronic (long-term) HAP impacts from well site production would be 

similar to the impacts for the Proposed Action. HAP impacts under Alternative B would be below all 

applicable REL and RfC exposure thresholds. For the suspected carcinogens (benzene, ethyl benzene, and 

formaldehyde) the maximum distance required to be below a one-in-one-million cancer risk level for 

production activities for either the MLE or the MEI analysis would be 1.25 miles as a result of the 

emissions for a single well pad with 16 wells in production. Mitigation measures for NOx emissions that 

will be required to demonstrate compliance with the 1-hour NO2 NAAQS will also decrease the predicted 

cancer risk impact for formaldehyde (see Section 4.5.9 Unavoidable Adverse Impacts and Additional 

Mitigation). 

Far-Field Modeling 

Criteria Pollutants Including Ozone. Criteria pollutant impacts would be similar to those presented in 

Section 4.5.4.1 for the Proposed Action. Alternative B sources would not contribute to modeled 

exceedances of the NAAQS, WAAQS or CAAQS for ozone or any other criteria pollutant. PSD 

increments would not be exceeded at any Class I or sensitive Class II areas. 

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Mid-Field Impacts 

Alternative B criteria pollutant impacts from project sources and regional sources, within and near the 

CD-C project area would be similar to the results shown in Table 4.5-10 for the Proposed Action. The 

cumulative impacts resulting from project and regional sources are below the applicable ambient air 

quality standards and the direct project impacts are below the PSD Class II Increments. 

AQRV Impacts 

Visibility Impacts. Visibility impacts estimated using the FLAG 2010 method at Class I and sensitive 

Class II areas resulting from Alternative B emissions would be similar to those presented in Table 4.5-11 

for the Proposed Action. 

Deposition Impacts. Nitrogen and sulfur deposition impacts under Alternative B would be similar to the 

impacts for the Proposed Action. 

Acidification at Sensitive Lakes. Potential sensitive lake acidification resulted from nitrogen and sulfur 

deposition impacts under Alternative B would be similar to the impacts for the Proposed Action, where 

modeling results indicated that there would be no ANC changes at any of the analyzed lakes that 

exceeded threshold values. 

Regional Climate Change and Greenhouse Gas Emissions 

The maximum greenhouse gas emissions resulting from Alternative B sources would be comparable to 

the emissions estimated for the Proposed Action. 

4.5.7.4 Alternative C: Cap on Surface Disturbance for High and Low-Density Development 

Areas 

Alternative C includes the construction and operation of 8,950 natural gas wells, associated roads, and 

production facilities, including compression and gas processing facilities. The proposed natural gas wells 

would be drilled using a combination of vertical and directional drilling techniques. 

Near-Field Modeling 

Near-field modeling impacts for Alternative C would be similar to those presented in Section 4.5.4 for the 

Proposed Action. Impacts from Alternative C production sources would be below the NAAQS or 

WAAQS, and would not exceed the PSD Class II increments. 

Alternative C field development source emissions would not result in any exceedances of the NAAQS or 

WAAQS at the 250-meter distance; however, modeled impacts for the 100-meter receptor distance case 

did result in short-term concentrations that were predicted to be above the 1-hour NO2 NAAQS, the 24­

hour PM2.5 NAAQS, and the 24-hour PM10 WAAQS. In order to demonstrate compliance with the 

NAAQS and WAAQS additional mitigation measures will be required through application of one or more 

emission control measures, such as those described in Section 4.5.9 Additional Mitigation. 

The maximum predicted acute and chronic (long-term) HAP impacts from well site production would be 

similar to the impacts presented in Section 4.5.4.1 for the Proposed Action. HAP impacts under 

Alternative C would be below all applicable REL and RfC exposure thresholds. For the suspected 

carcinogens (benzene, ethyl benzene, and formaldehyde) the maximum distance required to be below a 

one-in-one-million cancer risk level for production activities for either the MLE or the MEI analysis 

would be 1.25 miles as a result of the emissions for a single well pad with 16 wells in production. 

Mitigation measures for NOx emissions that will be required to demonstrate compliance with the 1-hour 

NO2 NAAQS will also decrease the predicted cancer risk impact for formaldehyde (see Section 4.5.9 

Unavoidable Adverse Impacts and Additional Mitigation). 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 4-63 
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Far-Field Modeling 

Criteria Pollutants Including Ozone. Criteria pollutant impacts would be similar to those for the Proposed 

Action. Alternative C sources would not contribute to modeled exceedances of the NAAQS, WAAQS or 

CAAQS for ozone or any other criteria pollutant. PSD increments would not be exceeded at any Class I 

or sensitive Class II areas. 

Mid-Field Impacts 

CD-C Alternative C criteria pollutant impacts from project sources and regional sources within and near 

the CD-C project area would be similar to the results shown in Table 4.5-10 for the Proposed Action. The 

cumulative impacts resulting from project and regional sources would be below the applicable ambient air 

quality standards and the direct project impacts would be below the PSD Class II increments. 

AQRV Impacts 

Visibility Impacts. Visibility impacts estimated using the FLAG 2010 method at Class I and sensitive 

Class II areas resulting from Alternative C emissions would be similar to those presented in Table 4.5-11 

for the Proposed Action. 

Deposition Impacts. Nitrogen and sulfur deposition impacts under Alternative C would be similar to the 

impacts for the Proposed Action. 

Acidification at Sensitive Lakes. Sensitive lake acidification resulting from nitrogen and sulfur deposition 

impacts under Alternative C would be similar to the impacts presented in Section 4.4.1 for the Proposed 

Action, where modeling results indicated that there would be no ANC changes at any of the analyzed 

lakes that exceed threshold values. 

Regional Climate Change and Greenhouse Gas Emissions 

The maximum greenhouse gas emissions resulting from Alternative B sources would be comparable to 

the emissions estimated for the Proposed Action. 

4.5.7.5 Alternative D: Directional Drilling 

Alternative D includes the construction and operation of 8,950 natural gas wells, associated roads, and 

production facilities, including compression and gas processing facilities. The proposed natural gas wells 

would be drilled either conventionally, with a single vertical well bore on each well pad, or with multiple 

directional well bores from a single pad; however, the majority of the wells would be directional. 

Near-Field Modeling 

Near-field modeling impacts for Alternative D production facilities would be similar to those presented in 

Section 4.5.4.1 (Tables 4.5-4a and 4.5-4b) for the Proposed Action. Impacts from Alternative D 

production sources would below the NAAQS or WAAQS, and would not exceed the PSD Class II 

increments. 

The maximum modeled criteria pollutant impacts from well development activities associated with 

Alternative D would be similar to the Proposed Action; however, given that Alternative D is mainly a 

directional well drilling alternative, additional modeling scenarios are presented in this section for only 

multi-well cases. The maximum modeled criteria pollutant impacts from well development activities are 

shown in Tables 4.5-14a and 4.5-14b for both the 100-meter and 250-meter receptor distances from 

project sources. 

As described earlier in Section 4.5.7.1, the 1-hour NO2 and the 24-hour PM2.5 results are calculated as a 

three-year average based on modeling Alterative D field development and field production sources of air 

emissions. The scenarios modeled for determining air quality impacts from NOx emission sources 

included Tier 2 drill rig operation and multi-well pads with 16 wells in production. For PM2.5 emission 

4-64 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—AIR QUALITY
 

sources, the scenario modeled includes the emissions from 4 multi-well pads and access roads under 

construction, 4 Tier 2 drill rigs operating, and 4, 4-well pads in production. As indicated in Tables 4.5-

14a and 4.5-14b Alternative D field development source emissions would not result in any exceedances 

of the NAAQS or WAAQS at the 250-meter distance. However, modeled impacts for the 100-meter 

receptor distance case did result in short-term concentrations that were predicted to be above the 1-hour 

NO2 NAAQS, the 24-hour PM2.5 NAAQS, and the 24-hour PM10 WAAQS. 

Tables providing the individual annual modeled 8th highest daily maximum 1-hour NO2 concentrations 

and the individual annual modeled maximum 24-hour PM2.5 concentrations predicted for all modeling 

scenarios are presented in Appendix L of the AQTSD, and the results are discussed in AQTSD Section 

3.5.4. 

In order to demonstrate compliance with the NAAQS and WAAQS additional mitigation measures will 

be required through application of one or more emission control measures, such as those described in 

Section 4.5.9 Unavoidable Adverse Impacts and Additional Mitigation. 

Note that the emissions from field development activities would be temporary and would not consume 

PSD increment, and as a result are excluded from increment comparisons. 

Additional detail on near-field modeling methods and results is provided in Section 3.5 of the AQTSD. 

Table 4.5-14a. Field development sources, criteria pollutant modeling results: 100-meter receptor 

distance, Alternative D 

Scenario Pollutant Averaging 

Time 

Direct 

Modeled 

(μg/m3

) 

Background 

(μg/m3

) 

Total 

Predicted 

(μg/m3

) 

WAAQS 

(μg/m3

) 

NAAQS 

(μg/m3) 

4 Tier 2 Drill Rigs CO 1-hour 585.6 1,026.0 1,611.6 40,000 40,000 

8-hour 311.3 798.0 1,109.3 10,000 10,000 

16 Well Pad, Tier 2 

Drill Rig 

NO2 1-hour 

Annual 

123.51

 23.7 

75.0 

9.1 

198.5 

32.8 

n/a 

100 

188 

100 

4, 4-Well Pads, 4 Tier 

2 Drill Rigs 

NO2 1-hour 

Annual 

125.61

 25.6 

75.0 

9.1 

200.6 

34.7 

n/a 

100 

188 

100 

4 Tier 2 Drill Rigs SO2 1-hour 

3-hour 

24.62

 15.9 

19.7 

11.5 

44.3 

27.4 

n/a 

1,300 

196 

1,300 

24-hour 8.2 4.2 12.4 260 365 

Annual 1.2 3.8 5.0 60 80 

Multi-Well Pad and 

Access Road 

Construction 

PM10 24-hour 

Annual 

83.3

 4.9 

56.0 

13.5 

139.3 

18.4 

150 

50 

n/a 

50 

PM2.5 24-hour 23.93 9.2 33.1 n/a 35 

Annual 3.1 4.2 7.3 n/a 15 

1 NO2 1-hour concentrations are calculated as the 3-year average of the 8th highest daily maximum 1-hour concentrations. (16 well 

pad case includes 2 years of drill rig operation concurrent with 15 wells in production, and 1 year with 16 wells in production, 4, 4-

well pad case includes 1 year with 4 drill rig operation and 2 years with 2 drill rigs operation and 8 wells in production). The 

yearly maximum 8th highest daily maximum 1-hour NO2 concentrations for all modeled scenarios are provided in Appendix L of 

the AQTSD. 

2 SO2 1-hour concentration is 4th highest daily maximum 1-hour concentration. 

3 PM2.5 24-hour concentration calculated using 3-year average of the maximum modeled 24-hour concentrations (includes well pad 

and access road construction, tier 2 drill rig operation, and well production activities). The yearly maximum 24-hour PM2.5 

concentrations for all modeled scenarios are provided in Appendix L of the AQTSD. 

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Table 4.5-14b. Field development sources, criteria pollutant modeling results: 250-meter receptor 

distance, Alternative D 

Direct Total 

Scenario Pollutant 

Averaging 

Time 

Modeled 

(μg/m3

) 

Background 

(μg/m3) 

Predicted 

(μg/m3) 

WAAQS 

(μg/m3) 

NAAQS 

(μg/m3) 

4 Tier 2 Drill Rigs CO 1-hour 287.5 1,026.0 1,313.5 40,000 40,000 

8-hour 119.3 798.0 917.3 10,000 10,000 

16 Well Pad, Tier 2 

Drill Rig 

NO2 1-hour 

Annual 

102.01

 12.0 

75.0 

9.1 

177.0 

21.1 

n/a 

100 

188 

100 

4, 4-Well Pads, 4 

Tier 2 Drill Rigs 

NO2 1-hour 

Annual 

101.11

 14.8 

75.0 

9.1 

176.1 

23.9 

n/a 

100 

188 

100 

4 Tier 2 Drill Rigs SO2 1-hour 

3-hour 

13.12

 6.9 

19.7 

11.5 

32.8 

18.4 

n/a 

1,300 

196 

1,300 

24-hour 2.8 4.2 7.0 260 365 

Annual 0.5 3.8 4.3 60 80 

Multi-Well Pad and 

Access Road 

Construction 

PM10 24-hour 

Annual 

60.1

 2.5 

56.0 

13.5 

116.1 

16.0 

150 

50 

n/a 

50 

PM2.5 24-hour 15.83 9.2 25.0 n/a 35 

Annual 1.6 4.2 5.8 n/a 15 

1 NO2 1-hour concentrations are calculated as the 3-year average of the 8th highest daily maximum 1-hour concentrations. (16 well 

pad case includes 2 years of drill rig operation concurrent with 15 wells in production, and 1 year with 16 wells in production, 4, 4-

well pad case includes 1 year with 4 drill rig operation and 2 years with 2 drill rigs operation and 8 wells in production). The yearly 

maximum 8th highest daily maximum 1-hour NO2 concentrations for all modeled scenarios are provided in Appendix L of the 

AQTSD. 

2 SO2 1-hour concentration is 4th highest daily maximum 1-hour concentration. 

3 PM2.5 24-hour concentration calculated using 3-year average of the maximum modeled 24-hour concentrations (includes well pad 

and access road construction, tier 2 drill rig operation, and well production activities). The yearly maximum 24-hour PM2.5 

concentrations for all modeled scenarios are provided in Appendix L of the AQTSD. 

The maximum predicted acute and chronic (long-term) HAP impacts from well site production would be 

similar to the impacts presented in Section 4.5.4.1 for the Proposed Action. HAP impacts under 

Alternative D would be below all applicable REL and RfC exposure thresholds. For the suspected 

carcinogens (benzene, ethyl benzene, and formaldehyde) the maximum distance required to be below a 

one-in-one-million cancer risk level for production activities for either the MLE or the MEI analysis 

would be 1.25 miles as a result of the emissions for a single-well pad with 16 wells in production. 

Mitigation measures for NOx emissions that will be required to demonstrate compliance with the 1-hour 

NO2 NAAQS will also decrease the predicted cancer risk impact for formaldehyde (see Section 4.5.9 

Unavoidable Adverse Impacts andAdditional Mitigation). 

Far-Field Modeling 

Criteria Pollutants Including Ozone. Criteria pollutant impacts would be similar to those for the Proposed 

Action. Alternative D sources would not contribute to modeled exceedances of the NAAQS, WAAQS, or 

CAAQS for ozone or any other criteria pollutant. PSD increments would not be exceeded at any Class I 

or sensitive Class II areas. 

Mid-Field Impacts 

Alternative D criteria pollutant impacts from project sources and regional sources within and near the 

CD-C project area would be similar to results shown in Table 4.5-10 for the Proposed Action. The 

4-66 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
 

CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—AIR QUALITY
 

cumulative impacts resulting from project and regional sources would be below the applicable ambient air 

quality standards and the direct project impacts would be below the PSD Class II increments. 

AQRV Impacts 

Visibility Impacts. Visibility impacts estimated using the FLAG 2010 method at Class I and sensitive 

Class II areas resulting from Alternative D emissions would be similar to those presented in Table 4.5-11 

for the Proposed Action. 

Deposition Impacts. Nitrogen and sulfur deposition impacts under Alternative D would be similar to the 

impacts for the Proposed Action. 

Acidification at Sensitive Lakes. Sensitive lake acidification resulting from nitrogen and sulfur deposition 

impacts under Alternative D would be similar to the impacts presented for the Proposed Action, where 

modeling results indicated that there would be no ANC changes at any of the analyzed lakes that 

exceeded threshold values. 

Regional Climate Change and Greenhouse Gas Emissions 

The maximum greenhouse gas emissions resulting from Alternative D sources would be comparable to 

the emissions estimated for the Proposed Action. 

4.5.7.6 Alternative E: No Action 

Under the No Action Alternative, it is assumed that no new natural gas wells would be developed. Air 

pollutant concentration impacts would remain near current levels as a result of existing development. 

Near-Field Modeling 

There would be no new development under Alternative E (No Action). Therefore there would be no 

increase in ambient air concentrations and the existing project impacts would be below the NAAQS, 

WAAQS, and PSD Class II increments. There would be no change in current criteria pollutant and HAP 

concentrations impacts resulting from existing project area sources. 

Far-Field Modeling 

Criteria Pollutants Including Ozone. Criteria pollutant impacts would be less than the impacts presented 

in Section 4.5.4 for the Proposed Action, since there would be no new sources proposed under 

Alternative E. The existing CD-C project area sources would not contribute to modeled exceedances of 

the NAAQS, WAAQS, or CAAQS for ozone or any other criteria pollutant. PSD increments would not be 

exceeded at any Class I or sensitive Class II areas. 

Mid-Field Impacts 

Alternative E criteria pollutant impacts from existing project sources and regional sources within and near 

the CD-C project area are shown in Table 4.5-15. The cumulative impacts resulting from existing CD-C 

project and regional sources would be below the applicable ambient air quality standards and the direct 

project impacts would be below the PSD Class II increments. 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—AIR QUALITY
 

Table 4.5-15. Mid-Field criteria pollutant modeling results, Alternative E 

Pollutant Averaging 

Time 

Modeled 

Concentration 

from CD-C 

Project Sources 

(μg/m3

) 

Modeled 

Concentration 

from All Sources 

(μg/m3

) 

PSD Class II 

Increment1 

(μg/m3

) 

WAAQS 

(μg/m3) 

NAAQS 

(μg/m3) 

CO4 1-hour 

8-hour 

--

--

492.7 

357.6 

n/a 

n/a 

40,000 

10,000 

40,000 

10,000 

NO2 1-hour 

Annual 

47.6 

9.9 

44.12 

11.5 

n/a 

25 

n/a 

100 

188 

100 

O3 8-hour 3.3 142.4 n/a 147 147 

SO2 1-hour 

3-hour 

24-hour 

Annual 

0.08 

0.08 

0.03 

0.01 

30.83 

30.0 

11.3 

3.1 

n/a 

512 

91 

20 

n/a 

1,300 

260 

60 

196 

1,300 

365 

80 

PM10 24-hour 

Annual 

1.9 

0.8 

54.9 

7.4 

30 

17 

150 

50 

n/a 

50 

PM2.5 24-hour 

Annual 

1.4 

0.5 

17.9 

3.7 

9 

4 

n/a 

n/a 

35 

15 

1	 The PSD demonstrations serve information purposes only and do not constitute a regulatory PSD increment consumption 

analysis 

2 NO2 1-hour concentration is 8th highest daily maximum 1-hour concentration. Value includes contribution from NO. 

3 SO2 1-hour concentration is 4th highest daily maximum 1-hour concentration. 

4 No value is given for the CD-C Project CO concentration contribution because the CAMx source apportionment tool does not 

track CO. 

AQRV Impacts 

Visibility Impacts. Visibility impacts for Alternative E source emissions, estimated using both the FLAG 

2010 and BLM methods, would be below the 0.5 Δdv threshold at all of the Class I and sensitive Class II 

areas analyzed for both the 2005 and 2006 meteorological data. Visibility results are summarized in 

Section 4.6.1 of the AQTSD. 

Deposition Impacts. Modeling results for Alternative E source emissions indicated that there would be no 

nitrogen or sulfur deposition impacts that exceeded the BLM critical load values at any Class I or 

sensitive Class II area. Deposition impacts would be below the DAT for all Class I and sensitive Class II 

areas, with the exception of the Savage Run Wilderness Area, where impacts are above the DAT for 

nitrogen. Deposition impacts are summarized in Section 4.6.2 of the AQTSD. 

Acidification at Sensitive Lakes. Modeling results for Alternative E sources indicated that there would be 

no ANC changes at any of the 12 analyzed lakes that exceed the 10-percent threshold or the ΔANC<1 

μeq/L threshold for the two extremely sensitive lakes. Lake ANC impacts are summarized in Section 

4.6.3 of the AQTSD. 

Regional Climate Change and Greenhouse Gas Emissions 

The maximum greenhouse gas emissions resulting from Alternative E source emissions in year 2022 (the 

peak emissions year for the Proposed Action and for any of the action alternatives) are estimated at 4.8 

tg/yr of CO2 equivalent emissions. This represents a 0.5 tg/yr reduction in GHG emissions from year 2008 

CD-C existing project emissions levels. To place the Alternative E GHG emissions in context, the GHG 

emissions from the top five emitting coal-fired power plants in Wyoming range from 3 to 15 tg/year (data 

from <http://epa.gov/climatechange/emissions/ghgdata/-2010data.html>). 

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4.5.8 Impact Summary 

4.5.8.1 Summary of Near-Field Modeling Results 

Air pollutant impacts resulting from production activities associated with any of the CD-C Project 

alternatives over the life of the project would be below the NAAQS and WAAQS, and would not exceed 

the PSD Class II Increments. 

Well field development activities from the Proposed Action and project development alternatives 

(Alternatives A through D) including well pad construction and well drilling would not result in any 

exceedances of the NAAQS or WAAQS at the 250-meter distance; however, modeled impacts for the 

100-meter receptor distance case did result in short-term concentrations that were predicted to be above 

the 1-hour NO2 NAAQS, the 24-hour PM2.5 NAAQS, and the 24-hour PM10 WAAQS. In order to 

demonstrate compliance with the NAAQS and WAAQS additional mitigation measures will be required 

through the application of one or more emission control measures, such as those described in Section 

4.5.9 Unavoidable Adverse Impacts and Additional Mitigation. 

There would be no new development under Alternative E (No Action). Therefore there would be no 

increase in ambient air concentrations and the existing project impacts would be below the NAAQS, 

WAAQS, and PSD Class II Increments. 

The maximum predicted acute and chronic (long-term) HAP impacts from well field production for all 

project alternatives would be below all applicable REL and RfC exposure thresholds. For the suspected 

carcinogens (benzene, ethyl benzene, and formaldehyde) the maximum distance required to be below a 

one-in-one-million cancer risk level for production activities for either the MLE or the MEI analysis 

would be 1.25 miles as a result of the emissions for a single well pad with 16 wells in production. 

Mitigation measures for NOx emissions that will be required to demonstrate compliance with the 1-hour 

NO2 NAAQS will also decrease the predicted cancer risk impact for formaldehyde (see Section 4.5.9 

Unavoidable Adverse Impacts and Additional Mitigation). 

4.5.8.2 Summary of Far-Field Modeling Results 

Air pollutant emissions resulting from any of the CD-C project alternatives would make no significant 

contribution to modeled exceedances of the NAAQS, WAAQS, or CAAQS for ozone or any other criteria 

pollutant in the 2022 future year. The PSD increments would not be exceeded at any Class I or sensitive 

Class II area within the 4-km domain. 

The far-field assessment was performed using the Proposed Action emissions. The impacts resulting from 

all project development alternatives (Alternatives A through D) would be similar to impacts of the 

Proposed Action. Under Alternative E (No Action Alternative) there would be no additional impacts to air 

quality or AQRVs. 

For all pollutants except ozone, the modeling results show attainment throughout the 4-km domain except 

in the immediate vicinity of point sources unrelated to the CD-C project sources. Modeled exceedances of 

the CO, PM10 and PM2.5 standards are the result of impacts from a 2005 fire in Lincoln County, and the 

lone SO2 exceedance is highly localized and due to emissions from a Fremont County source. An ozone 

exceedance occurs at Boulder, Colorado, where CD-C has no significant contribution to ozone 

concentrations. 

Examination of the spatial scale and magnitude of the CD-C project contribution to criteria pollutant 

concentrations within the 4-km grid shows that exceedances of the ambient air quality standards in the 

2022 future year modeling would not be related to emissions from the CD-C project. 

The MATS-estimated maximum impact of the CD-C project on the 2022 future year 8-hour ozone Design 

Value is less than or equal to 0.8 ppb for both meteorological years. The two-year approximation to a 

2022 design value obtained using absolute model concentrations shows the CD-C project maximum 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—AIR QUALITY
 

ozone impact would be 1.6 ppb. For both the absolute modeled concentration and MATS results, the 

largest ozone impacts due to the CD-C project emissions would be in the vicinity of the project area. In 

Sublette County, where the only modeled exceedances of the 75 ppb NAAQS occurred, ozone impacts 

due to the CD-C project would be less than or equal to 0.04 ppb. The highest CD-C ozone contributions 

to ozone at Southwest Wyoming monitors would occur on days when modeled regional 8-hour ozone was 

low (<60 ppb). 

The visibility analysis showed 1 to 5 days with CD-C project visibility impacts greater than 0.5 dv at 

Class I and sensitive Class II areas over the course of the 2-year simulation of the future year emissions 

scenario. The simulation showed 1 day with CD-C project visibility impacts >1.0 dv during this period. 

The largest visibility impacts would occur at the Savage Run, Dinosaur, and Mount Zirkel areas. No other 

Class I or sensitive Class II areas had any day with visibility impacts >0.5 dv as a result of the CD-C 

project emissions. 

There would be no nitrogen or sulfur deposition impacts from any of the CD-C project alternatives 

exceeding BLM critical load values at any Class I/sensitive Class II areas; however, the DAT for nitrogen 

could be exceeded at several Class I areas near or downwind of the project area under the Proposed 

Action and action alternatives. 

There would be no ANC changes exceeding the 10-percent threshold or sensitive lake impacts where 

ΔANC<1 μeq/L due to emissions from any of the CD-C project alternatives. 

4.5.9 Unavoidable Adverse Impacts and Additional Mitigation Measures 

Substantial mitigation of air quality impacts from CD-C project NOx, CO, PM10, PM2.5, VOC, and HAP 

emissions would be achieved by the uniform application of WDEQ BACT and the Presumptive BACT 

permitting requirements following the WDEQ Oil and Gas Permitting Guidance. The Operators’ 

commitment to use only Tier 2 or better drill rigs (Section 2.2.1.7 Operator-Committed Practices) 

would further mitigate project impacts, reducing emissions of NOx, CO, PM10, PM2.5, and VOCs. 

Additional mitigation of predicted air quality impacts could be implemented by the following control 

measures: 

 Use of Tier 4 or equivalent drill rig engines, reducing NOx, CO, PM10, PM2.5, and VOC emissions. 

 Use of Tier 2 or better construction equipment, reducing NOx, CO, PM10, PM2.5, and VOC 

emissions. 

 Application of chemical suppressant on unpaved roads and additional watering during construction 

activities to minimize fugitive dust, reducing particulate (PM10 and PM2.5) impacts. 

 Centralization of well pad production facilities (e.g., heaters, flares, dehydration units), reducing 

NOx, CO, PM10, PM2.5, VOC, and HAP emissions and reducing truck traffic. 

 Field electrification, reducing NOx, CO, PM10, PM2.5, and VOC emissions. 

These and other mitigation options or control measures may already be in practice in the CD-C project 

area to varying degrees. The reduction in emissions brought about by application of any of these measures 

could be estimated with additional modeling based on more detailed descriptions of the actual drilling and 

production processes used by the Operators. However, additional and more detailed information related to 

those practices would be needed from the Operators. This information will be gathered, and additional 

modeling analyses will be performed, during preparation of the FEIS. The results of the revised modeling 

analyses based on the selection of mitigation measures will be presented in the FEIS. Mitigation measures 

determined to be necessary to demonstrate compliance with the applicable NAAQS and WAAQS, as 

predicted in the revised modeling analyses, will be a required condition in the Record of Decision. 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—VEGETATION 

 BIOLOGICAL ENVIRONMENT 

4.6 VEGETATION 

4.6.1 Introduction 

Direct impacts to existing native shrub/grassland communities on the CD-C project area resulting from 

project implementation include a short-term reduction of herbaceous vegetation and a long-term loss of 

shrubs due to soil disturbance and related construction activities. Indirect impacts to the vegetation 

resource may occur as a result of damage to biological soil crusts (BSCs); soil compaction; mixing of soil 

horizons; loss of topsoil productivity; increased soil-surface exposure; soil loss due to wind and water 

erosion; short- to long-term increased potential for invasive weed introduction and establishment; shifts in 

plant species composition and density; a potential reduction of livestock, wild-horse, and wildlife habitat 

quantity and/or quality; and changes in visual aesthetics. 

4.6.2 Management Objectives and Impact Significance Criteria 

The Rawlins RMP (BLM 2008a) prescribes management objectives associated with vegetation. Those 

applicable to the CD-C project are: 

1.	 Maintain, restore, and enhance vegetation communities to facilitate a healthy mix of successional 

stages (identified in activity plans) that incorporate age class, structure, and species composition 

into each vegetation type, consistent with site potential. 

2.	 Control the introduction and proliferation of noxious and invasive species and reduce established 

populations to acceptable levels determined through cooperation, consultation, and coordination 

with local, state, other federal plans, policies, and agency agreements. 

3.	 Maintain, restore, and enhance the health and diversity of plant communities through the use of 

management prescriptions (such as prescribed natural fire, burning, planting, seeding, and chemical, 

mechanical, biological, and grazing treatments or other treatments) in coordination with local, state, 

and federal management plans and policies. 

4.	 Maintain, restore, and enhance riparian, wetland, and upland vegetation to meet the Wyoming 

Standards for Healthy Rangelands. 

5.	 Maintain, restore, and enhance Special Status Plant Species (Threatened, Endangered, and BLM 

State Sensitive plant species) and unique plant communities. 

6.	 Utilize inventory and monitoring data to support vegetation management. 

7.	 Maintain connectivity between large, contiguous blocks of federal land by minimizing 

fragmentation of vegetative communities. 

The following criteria were considered in the assessment of impacts associated with the Proposed Action 

and alternatives and are the same as those contained in the Rawlins RMP FEIS (BLM 2008b). The impact 

on vegetation would be considered significant if any of the following were to occur: 

1.	 Any action or event that would remove a community’s unique attributes or ability to support other 

resource values within the planning period, or corrective actions that were beyond the scope of this 

document. 

2.	 The viability of protected plant species is jeopardized, with little likelihood of reestablishment after 

disturbance, or actions result in the need to list a species under the ESA. 

3.	 Actions that have the potential to remove sensitive plant species or substantially alter the habitat’s 

ability to support the species. 

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4.	 Reclaimed areas do not attain adequate vegetation groundcover and species composition to stabilize 

the site within five years from disturbance, or there is invasion and establishment of noxious or 

invasive weeds that contribute to unsuccessful reclamation. 

5.	 Introduction of noxious and invasive weeds into areas considered weed-free, or an increase in weeds 

where they already exist. 

4.6.3 Direct and Indirect Impacts 

Direct impacts to the vegetation resource would principally occur during the construction phase of the 

proposed project and would include removal of existing native vegetation and removal of topsoil and 

BSCs. To some extent, these impacts could be mitigated by successful implementation of reclamation 

practices, but about 40 percent of the disturbance would remain in an unvegetated state for the life of the 

project—30 to 50 years at each individual well site—while in use for access roads and well pad facilities. 

The remaining 60 percent would have reduced productivity while reclamation is in progress and would 

have an altered species composition and density for the life of the project and beyond, including a longterm loss of shrubs. 

Vegetation could be impacted indirectly as a result of soil and BSC compaction, mixing of soil horizons, 

loss of topsoil productivity, and increased soil-surface exposure resulting in soil loss due to wind and 

water erosion. Other indirect impacts could occur as a result of altered runoff hydrology due to roads, 

well pads, and other facilities, particularly on moderate to steep slopes. These sites reduce natural runoff 

to downslope locations and increase channelization of flows and gullying, which results in desertification 

effects including a lower water table, lower productivity and cover, and altered species composition 

below these facilities. 

Additional indirect impacts would occur due to deposition of dust on vegetation near roads and 

construction sites, reducing plant productivity and vitality. The increased surface disturbance as a result of 

project implementation would also provide opportunities for invasive plant species to establish and spread 

(See Section 4.7 Invasive, Non-Native Plant Species). 

4.6.3.1 Proposed Action 

Under the Proposed Action (Section 2.2.1), 8,950 new natural gas wells and construction of required 

ancillary facilities would be anticipated over the course of 15 years (development phase) within the 

project area. It is assumed that 42 percent of the wells (3,765) would be drilled from directional drilling 

pads. Over the estimated 10- to 15-year development phase, the Proposed Action is estimated to initially 

disturb a total of 47,200 surface acres (Table 4.0-1), which represents about 4.4 percent of the total land 

surface of the project area. During the projected 45- to 55-year life of the project, the initial 47,200 acres 

of disturbance would be reduced to about 18,861 acres depending upon time required for successful 

reclamation, future land uses, and future climatic conditions. Construction and installation of well pads, 

access roads, and ancillary facilities (compressors, pipelines, and other required features.) would directly 

reduce the extent of vegetation cover types. 

In addition to the 47,200 acres initially disturbed by implementation of the Proposed Action, an estimated 

60,176 historic disturbance acres already exist within the project area (Table 4.0-1). The addition of 

historic disturbance to Proposed Action disturbance would result in a grand total of 107,376 acres or 

about 10 percent of the total project area. Much of that earlier disturbance remains unvegetated and in 

use, an estimated 17,663 acres. Together with long-term disturbance from the Proposed Action, up to 

36,524 acres, or about 3.4 percent of the total project area would remain in an unvegetated state. 

The time required to achieve successful reclamation of disturbed areas is largely dependent upon Operator 

commitment, compliance with BLM reclamation guidelines and recommendations, future land uses, and 

environmental variables, especially the timing and amount of precipitation events. This would hold true 

for reclamation of herbaceous species, but not necessarily for native shrub establishment, especially in the 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—VEGETATION 

more xeric portions of the project area—approximately 590,272 acres, representing about 55 percent of 

the project’s land surface area—where Wyoming big sagebrush and saltbush flats and fans are the 

primary cover types (Table 3.6-1). 

The majority of development would likely occur in the Wyoming big sagebrush, greasewood flats and 

fans, and saltbush flats and fans primary cover types, which collectively occupy about 78 percent (Table 

3.6-1) of the project’s land surface area. Wyoming big sagebrush plant communities typically occur on 

sites with low precipitation and poor soil development, which increases the difficulty of reclamation and 

makes it likely that only initial shrub re-establishment would occupy disturbed sites during the estimated 

45- to 55-year life of the project. Greasewood communities occupy about 246,000 acres (Table 3.6-1) 

within the project area. They are primarily located within the Muddy Creek drainage in the southern 

portion of the project area and within several large greasewood-dominated flats in the Red Desert Basin 

area in the northern portion of the project area. These flats usually have clayey soils with a high salt 

content which increases the difficulty of reclamation. The saltbush flats and fans cover type occupies 

about 173,000 acres within the project area. This primary cover type is found on saline soils in small to 

large openings or can occur as “stringer” inclusions within the ATW or greasewood primary cover types. 

These saltbush stands are sparsely vegetated and bare soil often exceeds 60 percent of the total ground 

cover. Reclamation of saltbush/mixed desert-shrub cover type habitats can be difficult and the use of seed 

mixes with appropriate native, saline, and drought-tolerant plant species is mandatory. The ability to reestablish native vegetation on sensitive soil types (i.e., clayey, sandy, saline/sodic) is not welldocumented in this area of Wyoming. Although current technology exists to stabilize these areas and 

minimize soil erosion as revegetation is being carried out, there is currently a lack of local seed sources 

for native forb and shrub species, and the recovery rate to restore native shrubs such as saltbush and 

shadscale to their pre-existing condition is unknown. 

Due to the scarcity of wetland/riparian sites in the project area, the probability of well pads, roads, 

pipelines, and ancillary facilities impacting these resources is low. The Rawlins RMP (BLM 2008a) 

specifies that a 500-foot buffer be maintained around perennial waters, springs, wells, wetlands, and areas 

within 100 feet of the inner gorge of ephemeral channels be avoided. These restrictions not only protect 

perennial water sources and wetland/riparian sites, but basin big sagebrush sites which are often located in 

or adjacent to ephemeral drainages that provide pygmy rabbit habitat and serve as mid-summer Greater 

sage-grouse foraging areas. In addition, an applicable Nationwide Permit as authorized by Section 404 of 

the Clean Water Act would be required from the U.S. Army Corps of Engineers, Wyoming Regulatory 

Office, for any disturbance activities in wetlands or Waters of the U.S. The probability of removing 

wetland vegetation or disturbing any Waters of the U.S. is low due to their low occurrence within the 

project area and existing stringent federal and state laws and regulations providing for their protection. 

In general, in addition to the initial area of disturbance, the extent of impacts to all vegetation cover types 

would be influenced by the success of mitigation and reclamation efforts and the time period required for 

disturbed areas to return to pre-existing conditions. Reclamation success depends, in part, on the quality 

of topsoil salvaged, stockpile/redistribution methods in disturbed areas, precipitation, appropriate seed 

mixes, soil type(s), and soil pre-seeding preparation and moisture availability. 

In March 2011, the RFO issued reclamation guidelines for its management area (Instruction 

Memorandum [IM] WYD-03-2011-002). The guidelines provide direction for implementing the 

reclamation requirements of the Rawlins RMP and the Wyoming BLM Reclamation Policy (IM WY2009-022). The reclamation requirements of the RMP are found in Appendix 36 of that document and 

essentially require a site-specific reclamation plan for any surface-disturbing activity and annual 

monitoring and reporting of reclamation status. A full description of the new RFO reclamation guidelines 

and recommendations can be found in Appendix E and at <http://www.blm.gov/wy/st/en/field_offices/ 

Rawlins/reclamation.html>. 

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Indirect impacts to vegetation due to dust from unpaved roads would be variable throughout the project 

area, depending upon the primary factors cited in Section 3.6.4, Fugitive Dust Effects on Vegetation 

Health. 

Project operations could result in increased traffic in the project area with an increased potential to create 

fugitive dust that could affect vegetation quality and quantity as well as general plant health. Specific 

plant communities would experience varying degrees of impact depending on location, general 

abundance, browse use, topography, site reclamation potential, soil type, and precipitation regime. 

Recommendations to mitigate dust impacts to vegetation and long-term loss of sagebrush habitat would 

include constructing roads to a 95-percent compaction rating, and instituting an effective dust-suppression 

program using water and/or periodic applications of BLM-approved dust-suppression chemicals to more 

heavily traveled roads. 

4.6.3.2 Alternative A: 100-Percent Vertical Drilling 

Alternative A (Section 2.2.2) is similar to the Proposed Action except this alternative assumes that no 

wells would be drilled using directional drilling rigs. Impacts to the vegetation resource resulting from 

implementation of Alternative A would be similar to the Proposed Action with the notable exception that 

the total amount of initial disturbance would increase from 47,200 acres to 61,696 acres, or 31 percent. 

Long-term disturbance following successful reclamation would increase from a total of 18,861 acres to 

24,133 acres. Combined with the present historic disturbed acres, the grand total of disturbance as a result 

of Alternative A would be 121,872 acres of initial disturbance and 41,796 long-term acres, assuming 

successful reclamation. 

Implementation of Alternative A would affect a greater proportion of the vegetation resource due to the 

larger area of surface disturbance associated with additional well pads and their associated access road 

and pipeline rights-of-way. In addition, construction activities, increased soil-surface disturbance, and 

higher traffic volumes associated with Alternative A would likely increase the potential for the 

introduction and spread of invasive weed species and increase the total fugitive dust load within the 

project area. 

4.6.3.3 Alternative B: Enhanced Resource Protection 

Alternative B (Section 2.2.3) identifies those resources that may be more at risk from natural gas 

development and provides enhanced protections and mitigations for those resources. Alternative B also 

recognizes that development may be more intensive than currently expected and may result in impacts 

that occur faster than anticipated. This alternative would combine a prescriptive and adaptive 

management approach, which includes assessing the specific issue, designing and implementing a 

response, monitoring and evaluating results, and adjusting the management response when needed on a 

case-by-case basis. The enhanced resource protections would go into effect immediately and be applied to 

all future APDs. 

Under Alternative B, the types of impacts to the vegetation resource would be similar to those described 

for the Proposed Action (Section 4.6.3.1) but the initial disturbance would encompass 45,516 acres, an 

approximate 4-percent reduction from the Proposed Action, due largely to an increase in the amount of 

directional drilling. Assuming successful reclamation efforts, long-term disturbance would decrease to 

18,249 acres, a reduction of 612 acres compared to the Proposed Action. Factoring in the existing historic 

disturbance with future disturbance results in a grand total of 105,692 acres of initial disturbance and 

35,912 acres of long-term disturbance. 

Although no vegetation communities are specifically targeted in Alternative B, measures that are aimed at 

protecting wildlife, riparian, and aquatic habitats and minimizing surface disturbance and dust produced 

by project activity would all benefit vegetation communities. Indirect effects of fugitive dust on sensitive 

vegetation in or near riparian areas and aquatic habitats are anticipated to be low to none. Avoidance of 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—VEGETATION 

riparian and aquatic sites (including playas) is an RMP requirement (BLM 2008b). Consequently, most 

roads and permanent ancillary structures would be constructed outside the 500-foot perennial water buffer 

and/or the 100-foot ephemeral drainage buffer previously discussed, thus reducing the fugitive dust load 

in/near these habitats. 

4.6.3.4 Alternative C: Cap on Surface Disturbance, 60 Acres and 30 Acres per Section 

Under Alternative C (Section 2.2.4), the types of impacts to the vegetation resource would be similar to 

those described for the Proposed Action (Section 4.6.3.1). For this alternative, the scope and intensity of 

the impacts would be less widespread because of the surface-disturbance caps on unreclaimed areas. 

Maximum surface disturbance for this alternative would represent a decrease of 4,245 acres of initial 

disturbance and 1,543 acres of long-term disturbance (4 percent and 1.6 percent of the project area, 

respectively) compared to the Proposed Action. 

Under Alternative C, fewer well locations (approximately 5,300) would be developed. Therefore, fewer 

access roads would be developed and habitat fragmentation would be less extensive than under the 

Proposed Action. If development were to occur in the majority of undeveloped areas according to current 

spacing orders (160-acre well spacing, or four wells per section), then vegetation impacts in these areas 

that support large tracts of continuous shrub-steppe habitat types would be less than the Proposed Action. 

If, on the other hand, future development in these areas were to occur at greater densities (80- or 40-acre 

well spacing), then effects on vegetation would be greater than under the Proposed Action (Section 

4.6.3.1). 

4.6.3.5 Alternative D: Directional Drilling 

Under Alternative D (Section 2.2.5), the types of impacts to the vegetation resource would be similar to 

those described for the Proposed Action (Section 4.6.3.1) but the scope and intensity of the impacts 

would be less widespread because of the expected reduction in surface disturbance. Estimated initial 

surface disturbance for this alternative would be approximately 36,449 acres, a decrease of 10,751 acres 

(23 percent) from the Proposed Action (Table 2.4-1). The estimated 14,952 acres of long-term 

disturbance would be 3,909 acres less than the Proposed Action. The implementation of Alternative D 

would reduce the number of well locations developed to an estimated 4,032 compared to the estimated 

6,126 for the Proposed Action. In addition to not disturbing almost 11,000 acres of native herbaceous and 

woody vegetation, the 35-percent reduction in well locations associated with this alternative would likely 

lead to similar reductions in the number of access roads and road miles which would reduce the total 

fugitive dust load on nearby forage thus increasing its palatability to wildlife and livestock (depending 

upon the primary factors cited in Section 3.6.4, Fugitive Dust Effects on Vegetation Health). Healthy, 

undisturbed rangeland vegetation is recognized by range managers as the best natural defense against 

invasive-plant establishment and soil loss due to wind and water erosion. 

4.6.3.6 Alternative E: No Action 

Under the No Action Alternative, there would be no new disturbance to the vegetation resource. 

4.6.4 Impact Summary 

Direct impacts to existing native shrub/grassland communities within the CD-C project area would be 

similar under the Proposed Action and all alternatives—an initial reduction of herbaceous vegetation and 

a long-term loss of shrubs due to soil disturbance and related construction activities. Indirect impacts to 

the vegetation resource would also be similar under the Proposed Action and all action alternatives. The 

principal difference in impacts for each alternative is related to the amount of surface disturbance that 

would occur for each. The Proposed Action would initially disturb 47,200 acres. Alternative A would 

increase surface disturbance by 31 percent to 61,696 acres. Alternatives B, C, and D would each decrease 

surface disturbance and hence impacts to vegetation communities: Alternative B by about 4 percent to 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—VEGETATION 

45,516 acres, Alternative C by 9 percent to 42,955 acres, and Alternative D by 23 percent to 36,449 acres. 

Alternative E, because it would have no new development, would not add to surface disturbance. Surface 

disturbance for the Proposed Action and each alternative would be in addition to 60,176 acres of historic 

surface disturbance in the project area. Table 4.0-1 shows in detail the historic and anticipated surface 

disturbance figures for the Proposed Action and the alternatives. 

After initial disturbance, approximately 40 percent of the disturbance would remain in an unvegetated 

state for the life of the project and the other 60 percent would undergo interim reclamation. Long-term 

disturbance by action alternative ranges from a high of 24,133 acres for Alternative A to a low of 14,952 

acres for Alternative D. The degree of long-term impact on vegetation by any of the alternatives would 

depend on the success of reclamation. That in turn would depend upon compliance with current BLM 

reclamation guidelines and recommendations, future land uses, and future climatic conditions. This would 

be true for reclamation of the faster-growing herbaceous species, but not necessarily for slow-growing 

shrubs such as Wyoming big sagebrush and Gardner’s saltbush that are located in the more xeric portions 

of the project area. Appendix E describes the process by which the BLM intends to direct reclamation 

efforts and monitor the progress of reclamation. 

Initial impacts to the vegetation resource from the action alternatives would include removal of native 

shrub species and associated understory herbaceous cover, thus decreasing abundance of these native 

species. Long-term impacts would be positive, assuming successful revegetation of BLM-approved seed 

mixes which would provide a younger, more vigorous and nutritious food source for wildlife, livestock, 

and wild horses on reclaimed areas. 

4.6.5 Unavoidable Adverse Impacts and Additional Mitigation Measures 

Vegetation cover would be unavoidably lost on a short-term basis as a result of the surface disturbance 

related to construction of well sites and associated facilities on public, state, and private lands within the 

CD-C project area. The losses would be in addition to historical losses of vegetation from prior surface 

disturbance, together representing 10 percent or more of the surface of the CD-C project area. For the 

intermediate to long term, grasses and other herbaceous vegetation would recover with the successful 

implementation of the BLM reclamation guidelines and recommendations described in Appendix E. 

Because of the extended time needed for the recovery of shrubs and other woody vegetation, a long-term 

loss of such vegetation is unavoidable. No additional mitigation measures beyond those described in 

Appendix C and Appendix E would mitigate these impacts to the vegetation resource. Those alternatives 

that most reduce surface disturbance—Alternatives C and D—would minimize both the short- and longterm loss of vegetation. Project operations could result in increased traffic in the project area with an 

increased potential to create fugitive dust that could affect vegetation quality and quantity as well as 

general plant health. Recommendations to mitigate dust impacts to vegetation would include constructing 

roads to a 95-percent compaction rating, and instituting an effective dust-suppression program using 

water and/or periodic applications of BLM-approved dust-suppression chemicals to more heavily traveled 

roads. 

4.7 INVASIVE, NON-NATIVE PLANT SPECIES 

4.7.1 Introduction 

Impacts to vegetation and rangeland resources due to the infestation and establishment of invasive weeds 

would result with the implementation of all alternatives. Impacts would be the greatest during the 

development phase of the action alternatives but would occur throughout the life of the project due to 

vegetation and soil disturbance associated with energy-related activities such as road construction and 

maintenance, pipeline installation, and installation of ancillary facilities. 

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4.7.2 Management Objectives and Impact Significance Criteria 

The Rawlins RMP (BLM 2008a) prescribes management objectives associated with vegetation (Section 

4.6.2). Objective 2 applies specifically to invasive, non-native plant species: 

1.	 Control the introduction and proliferation of noxious and invasive species and reduce established 

populations to acceptable levels determined through cooperation, consultation, and coordination 

with local, state, other federal plans, policies, and agency agreements. 

Impacts due to invasive weed species would be considered significant if the following were to occur: 

1.	 Introduction of invasive weeds into areas considered weed-free, or an increase in invasive weed 

density where infestations already exist, to include both upland and wetland/riparian sites. 

2.	 An increase in invasive weeds in any grazing allotment that reduces or eliminates the opportunity to 

run the livestock of choice. 

3.	 The criteria for Wyoming BLM Standards for Healthy Rangelands cannot be met in any grazing 

allotment due to invasive weed infestations. 

4.	 Non-compliance with long-term reclamation standards and goals for energy-related disturbed sites. 

5.	 Non-compliance with current BLM reclamation guidelines and recommendations (Appendix E), or 

Appendix 36 of the Rawlins RMP (2008b) due to establishment of and failure to control invasive 

weeds that contribute to non-attainment of these long-term standards and goals. 

4.7.3 Direct and Indirect Impacts 

Impacts to vegetation and range resources would occur on public lands under the Proposed Action and all 

action alternatives due to an increase in surface disturbance, which could provide more suitable habitat for 

invasive weed infestations. 

The existing infestation of halogeton and other invasive species described in Section 3.7 may be 

increased by project activities. Vehicles and equipment traveling from weed-infested areas, within and 

outside the project area, could facilitate the spread of invasive weeds into previously weed-free areas in 

addition to facilitating the spread of seeds of existing invasive populations. Additional surface-disturbing 

activities would increase the potential for infestation and spread of invasive plant species. Invasive weed 

species usually thrive on newly disturbed surfaces and out-compete native plant species. Creation of new 

sites for weed infestations may occur in proximity to roads where fugitive-dust deposition on roadside 

plants reduces their density due to chronic diseases in photosynthesis and growth, thus providing a 

suitable habitat for invasive plants to establish. 

Annual production of livestock/wildlife forage could also be impacted through the spread of invasive 

weeds. The introduction, establishment, and spread of these species would reduce rangeland and forage 

quantity and quality by replacing preferred forage species, leading to a reduction in grazing capacity, and 

could lead to a greater amount of RFO rangeland acreage not meeting the national and Wyoming BLM 

Standards and Guidelines for Healthy Rangelands (BLM 1997). 

Without proper management and control, invasive plant species may cause widespread infestations. 

Additionally, some invasive species such as halogeton, black henbane, and houndstongue are poisonous 

and can kill or impair livestock if ingested. 

The continued establishment and spread of halogeton, an invasive, poisonous plant, due to energy-related 

activities, could lead to an increase in livestock (especially sheep) mortality. This could result in the 

reduction or elimination of the opportunity to run the livestock of choice, which would be a significant 

impact. Project implementation would increase the potential for increased invasive plant density in the 

project area as a result of increased surface disturbance. The potential for increased invasive weed 

infestation would be the greatest on project-related disturbances but would also likely occur on the 56,647 

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historic existing disturbed acres due to natural dissemination of seeds, whether by wind, humans, wildlife, 

or livestock. 

As detailed in the Rawlins RMP, Appendix 36 (2008b), the Operators would be responsible for the 

management and control of all invasive weed species on or related to project-related surface disturbances 

during the life of the project and would follow an approved BLM Pesticide Use Proposal (PUP) and 

reporting requirements. 

4.7.3.1 Proposed Action 

Implementation of the Proposed Action (Section 2.2.1) would increase the potential for increased 

invasive plant density on the project area as a direct result of increased surface disturbance. Construction 

and installation of well pads, access roads, and ancillary facilities (compressors, pipelines, and other 

infrastructure) would remove soil and vegetation. Invasive weed species usually thrive on newly disturbed 

surfaces such as road and pipeline rights-of-way and out-compete the more desirable native plant species. 

Under the Proposed Action, 8,950 new natural gas wells and construction of required ancillary facilities 

would be anticipated over the course of 15 years (development phase) within the project area. It is 

assumed that 42 percent of the wells (3,765) would be drilled from directional drilling pads. Over the 

estimated 10- to 15-year development phase, the Proposed Action is estimated to initially disturb a total 

of 47,200 surface acres, which represents about 4.4 percent of the total land surface of the project area. 

During the projected 45- to 55-year life of the project, the initial 47,200 acres of disturbance would be 

reduced to about 18,861 acres depending upon time required for successful reclamation, future land uses, 

and future climatic conditions. 

In addition to the 47,200 acres initially disturbed by implementation of the Proposed Action, an estimated 

60,176 acres of historic initial disturbance already exist within the project area (Table 4.0-1). The 

addition of this historic disturbance to new disturbance from the Proposed Action would result in a grand 

total of 107,376 acres of initial disturbance, or about 10 percent of the total project area. Much of that 

earlier disturbance (an estimated 17,663 acres) remains unvegetated and in use. Together with the CD-C 

project long-term disturbance, up to 36,524 acres, or about 3.4 percent of the total land surface of the 

project area, would remain in an unvegetated state. 

The potential for increased invasive weed infestations would be the greatest on project-related 

disturbances but would also likely occur on the 60,176 acres of historic existing disturbance due to natural 

dissemination of seeds by wind, humans, wildlife, or livestock. 

4.7.3.2 Alternative A: 100-Percent Vertical Drilling 

Alternative A (Section 2.2.2) is similar to the Proposed Action except this alternative assumes that no 

wells would be drilled using directional drilling rigs. Impacts to the vegetation resource resulting from 

implementation of Alternative A would be similar to the Proposed Action with the notable exception that 

the total amount of short-term disturbed acres would increase from a total of 47,200 acres (Proposed 

Action) to 61,696 acres (Alternative A) and the long-term disturbed acres following successful 

reclamation would increase from a total of 18,861 acres (Proposed Action) to 24,133 acres (Alternative 

A). Combined with the present historic disturbed acres, the grand total of disturbed acres as a result of 

Alternative A would be 121,872 acres of initial disturbance and 41,796 acres of long-term disturbance, 

assuming successful reclamation. 

Impacts on the spread of invasive plant species would be similar to the Proposed Action but Alternative A 

would be more likely to affect a greater proportion of the vegetation resource due to the larger area of 

surface disturbance from additional well pads and their associated access road and pipeline rights-of-way. 

In addition, construction activities, increased soil-surface disturbance, and higher traffic volumes 

associated with Alternative A would increase the potential for introduction and spread of invasive weed 

species within the project area. 

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4.7.3.3 Alternative B: Enhanced Resource Protection 

Alternative B (Section 2.2.3) identifies those resources that may be more at risk from natural gas 

development and provides enhanced protections and mitigations for those resources. Alternative B also 

recognizes that development may be more intensive than currently expected and may result in impacts 

that occur faster than anticipated. This alternative would combine a prescriptive and adaptive 

management approach, which includes assessing the specific issue, designing and implementing a 

response, monitoring and evaluating results, and adjusting the management response when needed on a 

case-by-case basis. The enhanced resource protections would go into effect immediately and be applied to 

all future APDs. 

Under Alternative B, impacts from the spread of invasive plant species would be similar to the Proposed 

Action (Section 4.6.3.1) but the alternative would create slightly less risk of infestation due to the 

diminished area of surface disturbance associated with a slight increase in directional drilling. The shortterm disturbance acres would be 45,516 acres, an approximate 4 percent reduction from the Proposed 

Action, due largely to an increase in the amount of directional drilling. Assuming successful reclamation 

efforts, the long-term disturbance would decrease to 18,249 acres, a reduction of 612 acres. Factoring in 

the existing historic disturbance acres with future short-term disturbance results in a grand total of 

105,692 acres of initial disturbance and 35,912 acres of long-term disturbance. 

4.7.3.4 Alternative C: Cap on Surface Disturbance, 60 Acres and 30 Acres per Section 

Under Alternative C (Section 2.2.4), impacts on the spread of invasive plant species would be similar to 

the Proposed Action (Section 4.6.3.1) but implementation of the alternative would affect a smaller 

proportion of the project area due to the reduced surface disturbance associated with the anticipated 

increase in directional drilling. The scope and intensity of the impacts would be less widespread because 

of the surface-disturbance caps on unreclaimed areas. Maximum surface disturbance for this alternative 

would be decreased initially by 4,245 acres and 1,543 acres in the long term (4 percent and 1.6 percent of 

the project area, respectively) when compared to the Proposed Action. 

With this alternative, fewer well locations (approximately 5,300) would be developed. Therefore fewer 

access roads would be developed and habitat fragmentation would be less extensive than the Proposed 

Action. If development were to occur in the majority of undeveloped areas according to current spacing 

orders (160-acre well spacing, or 4 wells per section), then invasive weed impacts in these areas would be 

less than the Proposed Action. If on the other hand, future development in these areas were to occur at 

greater densities (80- or 40-acre well spacing), then effects of invasive weeds would be greater than the 

Proposed Action (Section 4.6.3.1). 

4.7.3.5 Alternative D: Directional Drilling 

Under Alternative D (Section 2.2.5), impacts from the spread of invasive plant species would be similar 

to the Proposed Action (Section 4.6.3.1) but implementation of this alternative would affect a smaller 

proportion of the project area due to the reduced surface disturbance associated with the anticipated 

increase in directional drilling (Table 2.4-1). The scope and intensity of the impacts would be less 

widespread because of the reduced density of new surface-disturbing activities per section. 

Estimated initial surface disturbance for this alternative would be approximately 36,449 acres, a decrease 

of 10,751 acres (23 percent) from the Proposed Action. With this alternative there would be fewer well 

locations developed—an estimated 4,032 compared to the 6,126 estimated for the Proposed Action. 

Compared to the Proposed Action, this alternative would reduce surface disturbance by almost 11,000 

acres (17 sections) of potential new habitat for invasive plants. The 35-percent reduction in well locations 

associated with this alternative would likely lead to similar reductions in the number of access roads and 

road miles which often serve as primary dispersal corridors for invasive plant seeds. The reduction of 

road miles would also decrease total fugitive dust load to roadside vegetation which would be beneficial 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—INVASIVE, NON-NATIVE PLANT SPECIES 

to the prevention of weedy annual establishment (see Section 3.6.4, Fugitive Dust Effects on Vegetation 

Health). 

4.7.3.6 Alternative E: No Action 

Under the No Action Alternative, there would be no new disturbance except where APDs have been 

approved by the BLM for previously authorized activities. There would be no risk of direct infestation by 

invasive plant species as a result of this project, but infestations could still occur because of existing 

infestations. 

4.7.4 Impact Summary 

The risk of the infestation and spread of invasive plant species within the CD-C project area would be 

similar under the Proposed Action and all alternatives as initial surface disturbance would create 

opportunities for invasive species and development activity would increase the degree to which such 

species spread throughout the project area. The principal difference in impacts for each action alternative 

is related to the amount of surface disturbance that would initially occur for each. The Proposed Action 

would initially disturb 47,200 acres. Alternative A would increase surface disturbance by 31 percent to 

61,696 acres. Alternatives B, C, and D would each decrease surface disturbance and hence impacts from 

the spread of invasive species: Alternative B by approximately 4 percent to 45,516 acres, Alternative C by 

9 percent to 42,955 acres, and Alternative D by 23 percent to 36,449 acres. Surface disturbance for the 

Proposed Action and each alternative would be in addition to the 60,176 acres of historic surface 

disturbance in the project area. Table 4.0-1 shows in detail the historic and anticipated surface 

disturbance figures for the Proposed Action and the alternatives. 

After initial disturbance, approximately 40 percent of the disturbance would remain in an unvegetated 

state for the life of the project and the other 60 percent would undergo interim reclamation. Long-term 

disturbance by alternative ranges from a high of 24,133 acres for Alternative A to a low of 14,952 acres 

for Alternative D. The degree of long-term impact on vegetation by any of the alternatives would depend 

on the success of timely reclamation which in turn would depend upon compliance with current RFO 

reclamation guidelines and recommendations, future land uses, and future climatic conditions. As 

discussed in the RMP, Appendix 36 (2008a), the Operators would be responsible for the management and 

control of all invasive weed species related to project-related surface disturbances during the life of the 

project and would follow an approved BLM Pesticide Use Proposal (PUP) and reporting requirements. 

Chenoweth et al. (2010) recently completed a cost analysis for Pioneer Natural Resources in the Raton 

Basin (Trinidad, CO) and Encana Oil and Gas (Piceance Basin, CO) and concluded that estimated costs of 

proper site reclamation techniques between the two companies averaged about $16,125 to $22,589 per 

acre depending upon slope steepness. They also concluded that direct and indirect costs for reclamation 

failures varied between $20,070 and $43,000 per acre. It is evident that cost on reclamation failure sites 

can be more than twice the cost of initial proper reclamation, depending on severity of site degradation. It 

is imperative that Operators understand the importance of minimizing initial surface disturbance and reestablishing a competitive grass/forb cover as soon as feasible after disturbance to prevent successful 

establishment of invasive weeds at the site. 

4.7.5 Unavoidable Adverse Impacts and Additional Mitigation Measures 

Assuming construction, maintenance, and operation of well sites and associated disturbances on public, 

state, and private lands within the CD-C project area are in accordance with the BMPs and COAs 

described in Appendix C and assuming successful implementation of BLM reclamation guidelines and 

recommendations described in Appendix E, the infestation and spread of invasive plant species would be 

contained and there would be no long-term adverse impacts. Only one additional mitigation measure may 

be warranted: 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—INVASIVE, NON-NATIVE PLANT SPECIES 

	 To prevent the inadvertent introduction of invasive weeds, the Operators and their sub-contractors 

would thoroughly power-wash all field vehicles, particularly their undercarriages, before entering 

the project area. 

4.8 WILDLIFE 

4.8.1 Introduction 

The primary wildlife impacts likely to result from the Proposed Action or alternatives include (1) direct 

and indirect loss of wildlife habitats, (2) displacement of some wildlife species because of increased 

human access and activity, (3) an increase in the potential for collisions between wildlife and motor 

vehicles, (4) an increase in stress to wildlife and (5) disruption of life-history requirements of a species or 

population segment. 

The primary wildlife resources of interest within the project area include big game CWRs; big game 

migration routes; overlapping crucial habitats (multiple species); raptor nests; small mammals and 

neotropical birds; and upland game birds. A number of wildlife species, such as sage-grouse and 

mountain plover, are discussed in Section 4.9, Special Status Species. 

4.8.2 Management Objectives and Impact Significance Criteria 

The Rawlins RMP (BLM 2008b) prescribes the following management objectives associated with 

wildlife and fisheries resources (including Special Status Species): 

	 Maintain, restore, or enhance wildlife habitat in coordination and consultation with other local, 

state, and federal agencies and consistent with other agency plans, policies, and agreements. A full 

range of mitigation options will be considered when developing mitigation for project-level 

activities for wildlife and Special Status Species habitats. 

	 Maintain, restore, or enhance T&E species habitat, in coordination and consultation with the 

USFWS and other local, state, and federal agencies and consistent with other agency plans, policies, 

and agreements. 

	 Maintain, restore, or enhance designated BLM State Sensitive Species habitat to prevent listing 

under the ESA, in coordination and consultation with other local, state, and federal agencies and 

consistent with other agency plans, policies, and agreements. 

	 Maintain, restore, or enhance habitat function in crucial winter range. 

The following criteria were considered in the assessment of impacts associated with the Proposed Action 

and alternatives and are from the Rawlins RMP FEIS (BLM 2008a). Impacts to wildlife and fish would 

be considered significant if any of the following were to occur: 

1.	 Substantial loss of the biological integrity and habitat function of terrestrial and aquatic ecosystems 

that would make a species eligible for listing under the ESA. 

2.	 Management actions that result in substantial disruption or irreplaceable loss of vital and high-value 

habitats as defined in the Wyoming Game and Fish Commission Mitigation Policy (WGFD 2010a). 

The policy classifies big game crucial ranges as vital habitat and recommends that habitat function 

be maintained so that the location, essential features, and species supported by the habitat are 

unchanged. The policy also defines Moderate, High, and Extreme impact thresholds, of which High 

and Extreme impacts will be judged significant. 

Additionally, the RFO has determined that the following significance criterion should be included for this 

project: 

3. Any effect, whether direct or indirect, that results in long-term decreases in recruitment and/or 

survival rates for fish populations. 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—WILDLIFE 

4.8.3 Direct and Indirect Impacts 

4.8.3.1 Proposed Action 

The proposed natural gas development would disturb and alter approximately 47,200 acres of wildlife 

habitat over the next 15 years, in addition to the 60,176 acres previously disturbed by natural gas and 

other development. Reclamation of disturbed habitats would commence immediately and continue 

throughout the 15-year construction period, resulting in recovery of 18,861 acres of grass-dominated 

habitat (in one to several years, depending on precipitation and effectiveness of reclamation efforts). 

Recovery of shrubs to pre-disturbance levels would not occur during the life of the project. As indicated 

in Section 4.0.3, future project surface disturbance is most likely to occur in areas with already moderate 

to high development as previously developed areas are “filled-in” to the expected 40-acre spacing (16 

wells per section). However, some amount of development and surface disturbance can be expected 

throughout the project area. Depending on the well-spacing orders in an area and the degree to which 

directional drilling is used, disturbance per section could vary from as low as ten acres (four wells per 

section, all directionally drilled from one pad) to as high as 100 acres (16 wells, all vertically drilled from 

individual pads). The 160-acre well spacing orders designated for the undeveloped areas of the project 

area indicate an expectation of disturbance at the lower end of that spectrum. However, if spacing were to 

be reduced in any of those areas, the amount of disturbance per section would increase. 

Standard environmental protection measures prescribed as Conditions of Approval or used as BMPs 

(Appendix C) would be implemented under the Proposed Action and all alternatives. The Wildlife 

Monitoring and Protection Plan (Appendix I) would be followed to prevent, reduce, and detect impacts to 

wildlife and fish species throughout the life of the project. This plan serves two purposes: one is to 

describe the protocols to monitor wildlife responses, habitats, behavioral shifts, etc.; the other is to 

provide protocols to protect wildlife species and track the effectiveness of the monitoring and mitigation 

plan. BMPs implemented for other resource concerns may provide indirect protection for a variety of 

wildlife species. 

Wildlife habitats directly affected by the proposed project include areas that are physically disturbed by 

the construction of well pads, roads, pipelines, and production facilities; wildlife habitats indirectly 

disturbed include areas surrounding directly impacted habitats. Direct habitat loss from construction of 

the Proposed Action, equal to approximately 4.4 percent of the project area, would be in addition to the 

5.6 percent of the project area that has previously been disturbed. 

The long-term loss/reduced usability of shrub habitat within a portion of the project area could lead to an 

increase in use on remaining shrub habitats. This localized increase of use could lead to a long-term 

reduction of shrub habitats outside of immediate project disturbance areas. Currently, areas dominated by 

large and continuous stands of shrub communities have relatively low well densities or occur in sections 

with the lowest (160-acre) well-spacing orders or allowable well density. Timely reclamation of well 

pads, pipelines, and rights-of-way would provide grass and forb forage within one to several years 

depending on precipitation and effectiveness of reclamation efforts, while sagebrush and other important 

shrub species would require longer for re-establishment to pre-disturbance levels. Consequently, the total 

acres disturbed would constitute a long-term loss of shrubs and would not be fully usable by shrubdependent species for forage or shelter for over 20 years, although early seral stage shrubs would provide 

forage and/or shelter for various species in a shorter period of time. 

Disturbance during construction and production, such as human presence, dust, and noise may displace or 

preclude wildlife use during all seasons. Prohibiting construction, drilling, and other activities potentially 

disruptive to wildlife during sensitive time-periods (e.g. winter, breeding, or nesting) would reduce the 

probability of displacement during these critical times. The extent of displacement would be related to the 

duration, magnitude, and visual prominence of the activity, as well as the extent of construction and 

operational noise levels above existing background levels. Displacement could result in local reductions 

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in wildlife populations if adjacent, undisturbed habitats are at carrying capacity. In this situation animals 

are either forced into less-optimal habitats or they compete with other animals that already occupy 

unaffected habitats. Possible consequences of such displacement are lower survival, lower reproductive 

success, lower recruitment, and ultimately lower carrying capacity and reduced populations (WGFD 

2010a). 

The extent of wildlife displacement is impossible to predict for most species since the response to 

disturbance varies from species to species and can even vary between different individuals of the same 

species. After initial avoidance, some species may acclimate to the activity and begin to reoccupy areas 

previously avoided (Kuck et al. 1985). This acclimation and reoccupation may occur following 

construction and drilling operations when the project moves into the production phases where less noise 

and human activities would take place. However, there is no guarantee of acclimation, or reoccupation, if 

the number of roads or level of human activity exceeds tolerance thresholds of the individual animal. 

Human-caused surface disturbances such as well pads and roads can reduce use of surrounding habitat by 

wildlife. There is generally a zone of decreased use surrounding these sites due to the increased human 

activity. On average this zone extends to approximately 0.7 miles from development for big game species 

(Hebblewhite 2008). The area of aversion generally is the least for pronghorn and increases for elk and 

mule deer (Powell 2003, Berger 2006, Sawyer et al. 2006a). Consequently, development impacts to 

wildlife can extend beyond the physically disturbed area. 

Habitat fragmentation and isolation are difficult to determine and vary species to species, but they could 

occur as a result of gas-field developments, which typically are configured as point and linear 

disturbances scattered throughout broader areas. Although these types of disturbances do not usually 

create physical barriers to wildlife movement (although in the winter, high snow berms resulting from 

plowing along multiple access roads may disrupt some wildlife movement), the effective use of adjacent 

undisturbed habitats could diminish as densities of well pads, ancillary facilities, and roads increase. An 

increase in habitat fragmentation is not as readily apparent in areas with existing disturbance as in 

previously undisturbed areas, but adverse effects can be compounded when infill disturbance further 

reduces available habitat between existing disturbances, effectively eliminating areas of relatively 

undisturbed habitat to the point that animals are displaced from the general area. 

In addition, road/traffic-related dust would likely directly and indirectly impact 24.3 percent of the project 

area, which may result in some habitat avoidance (Section 3.6.4). Indirectly, this may increase inter- and 

intra-species competition for forage and thermal cover. In areas already at carrying capacity, individuals 

may be further displaced, possibly outside of the project area. Some animals may be displaced into lowerquality habitats which may lead to a reduction in reproductive rates or an increase in predation. In 

addition, roads provide access to the general public into areas that were previously undisturbed/ 

undeveloped. Human encroachment in the form of casual backcountry recreation, hunting, and poaching 

could occur at higher rates resulting in effects such as disturbance during sensitive periods, displacement, 

or increased mortality. 

Following drilling and well-completion operations, noise levels, vehicle traffic, and human activity would 

be reduced. As a result, species might acclimate to the well-pad production facilities and use habitats 

adjacent to such sites, particularly at night when facilities-maintenance activities do not occur (Thompson 

et al. 1998, Dzialak et al. 2011a; 2011b, Webb et al. 2011). 

The reaction of individual animals to noise and human presence varies depending on the intensity of the 

noise source and whether it is continuous or intermittent. Transient loud noises would provoke alarm 

responses; however, many animals habituate to more constant, lower-level noise sources that are not 

associated with negative visual stimuli or experiences such as being chased or hunted (reviewed in Busnel 

and Fletcher 1978; Weisenberger et al. 1996). Increased traffic levels on new and existing roads could 

increase the potential for wildlife/vehicle collisions for the life of the project. 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—WILDLIFE 

Pronghorn. The impacts with the potential for the greatest negative effects to pronghorn populations 

would occur in CWR. Pronghorn CWR encompasses 90,310 acres across the central and southeastern 

portion of the project area (Map 3.8-2). Based on habitat assessments conducted in 2007, 2008, and 2010 

at seven sites within the project area (Map 3.8-2; Table 3.8-3), pronghorn CWR is in largely fair 

condition (BLM unpublished data). Existing long-term disturbance and post-reclamation early-seral-state 

communities comprise approximately 2.6 percent of pronghorn CWR within the project area (Table 4.8-

1). Based on current well-spacing orders, as many as 1,232 new wells could be drilled within pronghorn 

CWR. Initially, an additional 3.6 percent of pronghorn CWR within the project area would be directly 

impacted by development of well pads and access roads under the Proposed Action. Assuming successful 

interim reclamation, as much as 6.2 percent of pronghorn CWR within the project area would remain 

disturbed for the life of the project. 

Table 4.8-1. Affected pronghorn Crucial Winter Range, new and existing surface 

disturbance 

Pronghorn Crucial Winter Ranges = 90,3101 

Existing and Proposed Disturbance 

In Crucial Winter Ranges 

Acres Percent 

Existing2 2,306 2.6% 

Proposed Action New3

 3,292 3.6% 

Combined4 5,598 6.2% 

Alternative A New 7,762 8.6% 

Combined 10,068 11.2% 

Alternative B New 3,175 3.5% 

Combined 5,481 6.1% 

Alternative C New 2,996 3.3% 

Combined 5,302 5.9% 

Alternative D New 2,746 3.0% 

Combined 5,052 5.6% 

1

 Designated CWR within the project area (WGFD 2011b).
 2

 Based on HWA 2008b.
 3

 Because the most important constituent vegetation communities within crucial winter ranges would not return
 

to functional condition for the life of the project, anticipated initial disturbance acres are used to represent the 

effective direct impact on these crucial winter ranges. 4 The combined existing long-term and proposed project initial disturbance represents the worst case scenario 

for anticipated crucial winter range habitat disturbance. 

The direct loss/reduced usability of sagebrush communities would increase use on remaining shrubs, 

potentially resulting in shrub health decline outside of the immediate project disturbances. This would 

have an impact on pronghorn due to their heavy use of sagebrush during winter. Over time, pronghorn 

habituate to certain disturbances, depending on the spatial relationship (i.e., distance) between these areas 

of disturbance to available forage, water, and thermal cover; however, Easterly (1991) found that 

pronghorn density was consistently higher in areas outside of developed areas. Standard mitigations 

prohibiting construction, drilling, and other activities potentially disruptive to pronghorn within CWR 

from November 15 to April 30 would reduce the probability of displacement during this critical time of 

the year. During the production phase, the application of BMPs identified in Appendix 15 of the RMP, if 

applied, would work to alleviate impacts to the species. This would likely serve to reduce stress, help 

maintain animal condition, and improve winter survival as the animals travel farther or are displaced to 

lower-quality range. 

Within the project area, pronghorn in the Red Desert herd generally migrate from north to south to CWRs 

along I-80. Pronghorn in the Bitter Creek and Baggs herds migrate from higher elevations to CWR along 

Muddy Creek and WY 789. I-80 presents a formidable barrier to north-south migration movements 

between the Red Desert herd and the Bitter Creek and Baggs herds (Map 3.8-1). In addition, fences along 

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WY 789 create a migration barrier that impedes pronghorn movement across the highway. Pronghorn 

found east of the highway are generally restricted to crucial winter habitat found along Muddy Creek and 

against WY 789, creating a trap to animal movement similar to I-80. WGFD (2011) reported, “Direct loss 

of winter habitat can cause a major impact because of the high sensitivity of pronghorn to wildlife 

unfriendly fencing, thus possibly causing a situation where pronghorn are trapped on unsuitable habitat 

increasing winter kill.” This situation occurred during the winter of 2007-2008 in the Baggs Herd Unit, 

when pronghorn were migrating over fences along WY 789. Numerous rangeland fences throughout the 

project area also impede the movement of individuals to suitable winter habitat. Fences can prevent the 

animals from escaping human disturbance associated with field-development activity. For example, 

animals may have to follow migration barriers such as fences for great distances before finding a way 

through towards better winter habitat (J. Gregson, pers. com. 2012). Development of the project would 

compound the impacts of barriers to migrations. The inability to move through the area may force 

individuals to use less-suitable winter habitats, increase physiological stress, increase potential for 

starvation, and increase mortality and an overall decline in population size. Surface-disturbing and 

disruptive activities in big game migration and transitional ranges would be managed on a case-by-case 

basis, while new fences in migration corridors would only be allowed if they meet BLM standards 

(Rawlins RMP, p. 2-54). 

Increased traffic levels on new and existing roads could increase the potential for wildlife/vehicle 

collisions. New roads also provide access to the general public into areas that were previously 

undisturbed/ undeveloped. Human encroachment in the form of casual backcountry recreation, hunting, 

and poaching could occur at higher rates resulting in effects such as disturbance during sensitive periods, 

displacement, or increased mortality. 

The level of development within pronghorn CWR and migration corridors that would occur as a result of 

the Proposed Action is expected to exceed the significance criteria and to meet or exceed the WGFD 

(2010) definition of “High Impact” to pronghorn in crucial seasonal habitats, as follows: “Impairment of 

habitat function increases – the impact will be more difficult or at times impossible to effectively mitigate 

within the project area. The impact can be reduced but probably not eliminated through seasonal use 

restrictions and more intensive management and mitigation practices.” Implementation of the Proposed 

Action, compounded by the current condition of the crucial winter habitat, along with the additional stress 

and displacement of pronghorn during development (and to a lesser degree during production) would 

likely exceed impact Criterion 2 (substantial disruption or irreplaceable loss of vital habitat). 

Mule Deer. The impacts with the potential for the greatest negative effects to mule deer populations 

would occur in CWRs. Mule deer CWRs encompass 17,849 acres within the southeastern part of the 

project area (Map 3.8-4). Based on habitat assessments conducted in 2007, 2008, and 2010 at two sites 

within the project area (Map 3.8-4; Table 3.8-4), the condition of mule deer CWR appears to have 

declined, possibly as a result of the severe winter of 2007–2008 (BLM unpublished data, WGFD 2011). 

Existing long-term disturbance and post-reclamation early-seral-state communities comprise less than 2.3 

percent of mule deer CWR within the project area (Table 4.8-2). Based on current well-spacing orders, as 

many as 298 new wells could be drilled within mule deer CWR. Initially, an additional 4.5 percent of 

mule deer CWR within the project area would be directly impacted by development of well pads and 

access roads under the Proposed Action. Assuming successful interim reclamation, as much as 6.8 percent 

of mule deer CWR within the project area would remain disturbed for the life of the project. 

The impacts of habitat disruption common to all big game species are discussed in detail earlier in this 

section. Reduction in winter range size and quality of available habitat may decrease the carrying capacity 

of the overall winter range (Sawyer et al. 2006b). In addition to the direct removal of habitat due to the 

development of pads and associated ancillary facilities, disturbances from drilling activities and traffic 

would affect the use of the habitat immediately adjacent to these areas. Indirect habitat loss can be 

substantially greater than the direct loss of habitat to roads and well-pad construction. Sawyer et al. 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—WILDLIFE 

(2006b) found that winter mule-deer habitat selection and distribution patterns have been affected by 

development, specifically road networks and well pads; mule deer had a higher probability of use in areas 

farther away from well pads as development progressed. Predictive maps also suggest that some habitats 

considered “high probability of use” areas prior to development, changed to “low probability of use” 

areas as development progressed, and vice-versa (Sawyer et al. 2006b). 

Table 4.8-2. Affected mule deer Crucial Winter Range, new and existing surface disturbance 

Mule Deer Crucial Winter Range = 17,8491 

Existing and Proposed Disturbance in Crucial 

Winter Range 

Acres % 

Existing2 404 2.3% 

Proposed Action New3

 796 4.5% 

Combined4 1,200 6.8% 

Alternative A New 1,877 10.5% 

Combined 2,281 12.8% 

Alternative B New 768 4.3% 

Combined 1,172 6.6% 

Alternative C New 724 4.1% 

Combined 1,128 6.4% 

Alternative D New 664 3.7% 

Combined 1,068 6.0% 

1 Designated winter and Winter/Yearlong within the project area (WGFD 2011b). 

2 Based on HWA 2008b. 

3 Because the most important constituent vegetation communities within crucial winter range would not return to functional 

condition for the life of the project, anticipated initial disturbance acres are used to represent the effective direct impact on these 

crucial habitats. 

4 The combined existing long-term and proposed project initial disturbance represents the worst case scenario for anticipated 

crucial winter range habitat disturbance. 

As discussed above (Pronghorn), prohibiting construction, drilling, and other activities potentially 

disruptive to mule deer within CWR from November 15 to April 30 would reduce the probability of 

displacement during this critical time of the year. During the production phase, the application of BMPs 

identified in Appendix 15 of the RMP would help alleviate impacts to the species. This would likely help 

reduce stress, maintain animal condition, and improve winter survival of the animals as they travel farther 

or are displaced to lower-quality range. Over time, mule deer habituate to certain disturbances, depending 

on the spatial relationship (i.e., distance) between these areas of disturbance to available forage, water, 

and thermal cover; however, Sawyer et al. (2006a) found that areas within 2.3 miles of well pads have 

lower predicted probabilities of use compared to undeveloped areas. Mule deer are adaptable and may 

adjust to non-threatening, predictable human activity (Irby et al. 1988). 

Recent research has identified migration routes used by mule deer adjacent to the project area (Sawyer 

2007). Mule deer appear to move between the higher elevations of the Atlantic Rim in the east to lower 

elevations along Red Creek Rim to the southwest, skirting the eastern edge of The Bluffs, a prominent 

geographic feature in the extreme southern portion of the project area (Sawyer 2007). Research into mule 

deer migration routes will continue to better inform and refine mapping. Numerous rangeland fences 

throughout the project area impede the movement of individuals to suitable winter habitat. Fences also 

prevent the animals from escaping human disturbance associated with field-development activity. For 

example, animals may have to follow migration barriers such as fences for great distances before finding 

a way through towards better winter habitat (J. Gregson, pers. com. January 2012). Development of the 

project would compound the impacts of barriers to migration. The inability to move through the area may 

force individuals to use less-suitable winter habitats, increase physiological stress, increase potential for 

starvation, and increase mortality and an overall decline in population size. Surface-disturbing and 

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disruptive activities in big game migration and transitional ranges would be managed on a case-by-case 

basis, while new fences in migration corridors would only be allowed if they met BLM standards 

(Rawlins RMP, p. 2-54). 

Increased traffic levels on new and existing roads would increase the potential for wildlife/vehicle 

collisions. 

The level of development within mule deer CWR and migration corridors that would occur as a result of 

the Proposed Action is expected to exceed the significance criteria and to meet or exceed the WGFD 

(2010) definition of “High Impact” to mule deer in crucial seasonal habitats: “Impairment of habitat 

function increases – the impact will be more difficult or at times impossible to effectively mitigate within 

the project area. The impact can be reduced but probably not eliminated through seasonal use restrictions 

and more intensive management and mitigation practices.” Implementation of the Proposed Action, 

compounded by the current condition of the crucial winter habitat, along with the additional stress and 

displacement of the mule deer during development, and to a lesser degree during production, would likely 

exceed impact significance Criterion 2 (substantial disruption or irreplaceable loss of vital habitat). 

Application of the same additional mitigation measures described for pronghorn could work toward 

reducing the impacts of the Proposed Action on mule deer. 

Elk. No elk CWR has been identified within the project area (Map 3.8-6), and migration routes have not 

been identified and documented. The majority of the project area is classified as “limited/no importance” 

and “undetermined/ undocumented” for elk use (WGFD 2010a). Small portions of the area are classified 

as “yearlong” and “winter” elk habitat (Map 3.8-6). Therefore, this project is not expected to alter or 

block elk movements. However, elk are generally believed to be more sensitive to human activities than 

pronghorn or mule deer, and they may be displaced in construction areas from 0.6 to 1.2 miles depending 

on the season (Powell 2003). Elk would likely habituate to the physical presence of gas wells (Van Dyke 

and Klein 1996); however, elk rarely adjust to the continued human presence required during the 

production phase of the project (Morrison et al. 1995). Following drilling and well-completion 

operations, noise levels, vehicle traffic, and human activity would be reduced. As a result, species might 

acclimate to the well-pad production facilities and use habitats adjacent to such sites, particularly at night 

when facilities-maintenance activities do not occur (Thompson et al. 1998, Dzialak et al. 2011a and 

2011b, Webb et al. 2011). 

With the increase in roads and potential recreational access to the area, displacement of elk in the limited 

areas of known elk use is likely during all phases of development. That said, and unless future studies 

demonstrate otherwise, impacts to elk populations due to habitat removal or modification; displacement, 

stress, or migration disruption; and increased vehicular collisions are not expected to exceed the impact 

significance criteria because high-value habitat (CWR and migratory routes) within the project area is 

very limited. 

Application of the same additional mitigation measures described for pronghorn and mule deer would 

work to reduce the impacts of the Proposed Action on elk. 

Overlapping Big Game Crucial Winter Range. Areas of overlapping big game CWR and sage-grouse 

core population areas are of greater importance because they provide crucial habitat for more than one 

species (WGFD 2010a); such areas occur within the project area (Map 3.8-7). Thirty-eight percent of 

overlapping big game CWR is on private and state lands where there are no protections against 

disturbance of animals during crucial time-periods (November 15 – April 30). Indirectly, this may 

increase inter- and intra-species competition (between different species and among individuals of the 

same species) for forage and thermal cover. This may force animals to use lower-quality habitats, which 

may lead to a reduction in reproductive rates or an increase in predation and/or mortality. The level of 

development of the Proposed Action within big game CWR, compounded by the current condition of the 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—WILDLIFE 

crucial winter habitat (Tables 3.8-3 and 3.8-4), would likely exceed impact significance Criterion 2 and 

meet the WGFD (2010) definition of “High Impact.” 

Consistent with the WGFD oil and gas development recommendations (WGFD 2010a), the mitigation 

measures listed for pronghorn and mule deer in the previous narratives would apply as well to the 

overlapping big game CWR. 

Raptors. The impacts with the potential for the greatest negative effects to raptor populations include 

nest-abandonment and failure due to increased human disturbance, loss of nesting and feeding habitat, 

and potential for increased vehicle collisions. There are 938 raptor nest sites (known to date) located in or 

within one mile of the project area. The BLM places year-round buffers around active raptor nest sites, 

precluding well locations, roads, ancillary facilities, and other surface structures requiring repeated human 

presence and applies a larger buffer during the nesting period (BLM 2008a). The size of buffers around 

active nests varies by species, with the largest buffers being one mile for bald eagles, golden eagles, and 

ferruginous hawks. Surface-disturbing activities would be prohibited from as early as February 1 (e.g. 

Great Horned Owl) to as late as September 15 (e.g. Burrowing Owl), depending on species. The amount 

of short-term change in prey-base populations created by construction is expected to be small in 

comparison to the overall level of small-mammal populations. While prey populations on the project area 

would likely sustain some reduction during the development phase of the project, most prey species 

would be expected to rebound to pre-disturbance levels following initial reclamation. Once reclaimed, 

these areas would likely promote an increased density and biomass of small mammals that is comparable 

to those of undisturbed areas (Hingtgen and Clark 1984). 

Some raptors feed on carrion on and along the roads, while others (owls) may attempt to capture small 

rodents and insects that are illuminated in headlights. These raptor behaviors put them in the path of 

oncoming vehicles where they are in danger of being struck and killed. 

Because of the buffers and restriction on activity around raptor nests and the fact that most of the prey 

utilize habitat that can be reclaimed in a timely fashion, the impact from the Proposed Action is not 

expected to exceed the significance criteria. 

Mitigation could be imposed to reduce the chance of collisions between vehicles and raptors by requiring 

that drivers undergo training that describes the circumstances under which vehicular collisions are likely 

to occur and measures that can be taken to minimize them. 

Small Mammals and Neotropical Songbirds. Construction disturbances would reduce habitat 

availability for a variety of small bird and mammal species. The temporary disturbances that would occur 

during the 15-year construction period would tend to favor early-succession wildlife species such as 

horned larks and ground squirrels, and would tend to adversely impact mid-to-late-succession species, 

such as loggerhead shrikes and voles. The long-term disturbance would have a minor effect on wildlife 

species not dependent upon shrubs. In addition to the direct-disturbance acreage, dust would directly and 

indirectly impact 24.3 percent of the project area (Section 3.6.4). These impacts would include habitat 

avoidance by birds and small mammals. Indirectly, this could increase inter- and intra-specific 

competition for nesting and foraging areas. In areas already fully occupied, density-dependent species 

would be further displaced, possibly outside of the project area. 

A variety of shrub-dependent songbirds could be displaced by the reduction in habitat. Although there is 

no way to accurately quantify these changes, the displacement would be long-term. Birds are highly 

mobile and would disperse into surrounding areas and use suitable habitats to the extent that they are 

available. Standard mitigation measures would indirectly help songbirds during critical time-periods, and 

impacts to nesting and foraging habitats are expected to be minimal. Therefore, impacts from this 

alternative are not likely to significantly reduce populations within the project area due to the abundance 

of undisturbed habitat that would remain. 

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The primary small mammals found in the project area include, but are not limited to, cottontail rabbits, 

various mouse and vole species, northern pocket gophers, white-tailed jackrabbits, and ground squirrels. 

The initial phases of surface disturbance would result in some direct mortality and displacement of small 

mammals from construction sites. Quantifying these changes is not possible because population data are 

lacking. However, the impact is likely to be minor, and the relatively high reproductive rate of these small 

mammals would enable populations to quickly repopulate the area following interim reclamation. Most of 

these species would benefit from an increase in grass-dominated vegetation resulting from reclamation 

activities. 

Development of the project could result in some unintentional, direct mortality of small birds and small 

mammals from vehicle collisions; however, this mortality is expected to be negligible and is not likely to 

significantly reduce populations within the project area. Overall, if standard prescribed environmental 

protection measures and BMPs (Appendix C) and the Wildlife Monitoring and Protection Plan 

(Appendix I) are implemented under the Proposed Action, the impacts on songbird and small-mammal 

populations are not expected to exceed the impact significance criteria. 

Upland Game Birds. Greater sage-grouse, Columbian sharp-tailed grouse, and mourning doves occur or 

potentially occur within the project area and may be impacted to varying degrees by the project. 

Mourning doves are highly adaptable habitat generalists; impacts would be negligible and not affect their 

long-term viability within the project area. Greater sage-grouse is designated as a candidate for listing 

under the ESA and is discussed in Section 4.9 Special Status Species. 

Fish. About 10 game-fish species and 20 non-game fish species may occur in the CD-C project area or 

adjacent to the project area, or in streams upstream or downstream of the project area (Table 3.8-6 ) Of 

these, 14 species, including six native species, are likely to be present within the project area. Of these 14 

species, four are BLM Sensitive Species. All of the 10 species that are not BLM Sensitive Species will be 

subject to the same types of impacts described in Section 4.9.3.1, Sensitive Fish Species. All of the 10 

species that are not BLM Sensitive Species, however, have a wide distribution within Wyoming (Baxter 

and Stone 1995); consequently, the project area and other human activities within the Muddy Creek and 

Great Basin watersheds may have localized population impacts, but these impacts should not impact their 

status range-wide. Only one reservoir in the project area has a recreational fishery, and no impacts to that 

fishery are anticipated. 

Part of Muddy Creek within the project area is listed as threatened by WDEQ for water quality (Section 

3.4.2.4); however, no segments listed as impaired are present within the project area. If any segments 

were to be classified as impaired, one of the requirements in the RMP is for intensive management of 

303(d) listed segments to address the problem. 

Refer to Section 4.9.3.1 for impacts to sensitive fish species. 

4.8.3.2 Alternative A: 100-Percent Vertical Drilling 

Alternative A would proceed with development across the project area similar to the Proposed Action, but 

would produce greater surface-disturbance due to an increase in the number of well pads, access roads, 

and pipelines. Initial facility construction within the project area would disturb and alter an estimated 

61,696 acres of wildlife habitat over the next 15 years, in addition to the 60,176 acres previously 

disturbed by natural gas and other development. This would be an increase of approximately 31 percent 

relative to the Proposed Action, and would mean that over 11 percent of the project area surface had been 

disturbed. Reclamation of disturbed habitats would commence immediately and continue throughout the 

15-year construction period, resulting in recovery (in one to several years, depending on precipitation and 

effectiveness of reclamation efforts) of 24,133 acres of grass-dominated habitat. Recovery of shrubs to 

pre-disturbance levels would not occur during the life of the project. 

The overall increase in the number of well pads and roads and the acreage initially disturbed would 

substantially increase habitat fragmentation. This would increase the overall habitat loss and displacement 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—WILDLIFE 

effects to wildlife species, as well as increase impediments within movement corridors. An increase in 

disturbance of wildlife habitat would impact all species and increase the time required, long-term, to 

return the functionality of the habitat in the project area. The degree of impact would vary by species. 

Impacts would be the same for all species as identified in Section 4.8.3.1 above, except as discussed 

below. 

Pronghorn. Initially, an additional 8.6 percent of pronghorn CWR would be directly impacted by 

development of well pads and access roads under Alternative A (Table 4.8-1). Even assuming successful 

interim reclamation, 11.2 percent of pronghorn CWR would remain disturbed for the life of the project. 

The direct loss/reduced usability of big sagebrush communities (Wyoming and mountain) would increase 

use on remaining shrubs, resulting in shrub health decline outside of the immediate project disturbances. 

This would have the greatest impact on pronghorn due to their reliance upon sagebrush habitats during 

winter. This level of development within pronghorn CWR and migratory routes (half again as much as the 

Proposed Action), compounded by the current condition of the crucial winter habitat, along with the 

additional stress and displacement during the production phase, would exceed impact significance 

Criterion 2 and the WGFD definition of “Extreme Impact,” even if standard mitigations are applied. 

Mule Deer. Initially, an additional 10.5 percent of mule deer CWR would be directly impacted by 

development of well pads and access roads under Alternative A (Table 4.8-2). Assuming successful 

interim reclamation, as much as 12.8 percent of mule deer CWR, including migration routes, within the 

project area would remain disturbed for the life of the project. This level of development within mule deer 

CWR (almost twice that of the Proposed Action), compounded by the current condition of CWR forage, 

along with the additional stress and displacement during the production phase, would exceed Criterion 2 

and the WGFD definition of “Extreme Impact.” 

Elk. No elk CWR exists in the project area; therefore, impacts to elk populations, although higher than 

the Proposed Action, are not expected to exceed the impact significance criteria. 

Overlapping Big Game Crucial Winter Range. This alternative would impact additional acreage of 

overlapping CWR and correspondingly increase the likelihood of exceeding Criterion 2 and the WGFD 

definition of “Extreme Impact.” 

Raptors. With the application of the RMP (BLM 2008a) required avoidance and mitigation measures 

(Section 4.8.3.1), impacts are not expected to exceed the significance criteria. 

Small Mammals and Neotropical Songbirds. Under this alternative, an expansion of total acres of 

disturbance would increase direct and indirect impacts to small birds and mammals relative to the 

Proposed Action. However, if standard prescribed environmental protection measures and BMPs 

(Appendix C) and the Wildlife Monitoring and Protection Plan (Appendix I) are implemented, and 

surface-disturbing and disruptive activities are intensively managed as required in the RMP (BLM 2008a, 

p. 2-53), impacts are not expected to exceed the impact significance criteria. 

Fish. The types of impacts to fish would be the same as for the Proposed Action, but because of the larger 

surface area affected (~14,500 acres more, ~35 percent more, initial; ~5,000 acres more long-term), the 

magnitude of impacts would be proportionally greater. 

4.8.3.3 Alternative B: Enhanced Resource Protection 

The Enhanced Resource Protection (ERP) alternative was developed to avoid significant impacts to 

resources of concern by implementing additional protections and mitigations beyond those normally 

applied (e.g. BMPs, Wildlife Monitoring and Protection Plan). The enhanced resource protections would 

go into effect immediately and be applied to all future APDs. 

The ERP alternative also recognizes that development may be more intensive than currently expected and 

may result in impacts occurring on wildlife habitats and populations faster than anticipated. Therefore, 

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this alternative includes surface-disturbance and population thresholds for some specifically designated 

high-value resources. If these surface-disturbance or population thresholds were reached, additional 

protection measures would be implemented, specific to each species. The alternative would combine 

prescriptive and adaptive management approaches that include assessing the specific issue, designing and 

implementing a response, monitoring and evaluating results, and adjusting the management response 

when needed on a case-by-case basis. See Section 2.2.3 for a detailed description of this alternative. 

Three general requirements are applied across the board in this alternative: (1) uniform application of 

dust-abatement procedures, (2) environmental awareness training for all employees and subcontractors, 

and (3) the BLM will require remote monitoring at well pads when a surface disturbance threshold of 5 

percent is reached for applicable resources. 

Under the ERP, initial facility construction within the project area would disturb and alter an estimated 

45,516 acres of wildlife habitat over the next 15 years, in addition to the 60,176 acres previously 

disturbed by natural-gas and other development. This would be a slight decrease relative to the Proposed 

Action. Reclamation of disturbed habitats would commence immediately and continue throughout the 15­

year construction period, resulting in recovery (in one to several years, depending on precipitation and 

effectiveness of reclamation efforts) of 18,249 acres of grass-dominated habitat. Recovery of shrubs to 

pre-disturbance levels would not occur during the life of the project. 

Under this alternative, pronghorn and mule deer CWR and migratory corridors would receive enhanced 

protections. Enhanced protections for Special Status Species are discussed in Section 4.9. 

Pronghorn and Mule Deer Crucial Winter Range and Migration Corridors. Initially, an additional 

3.5 percent of pronghorn and 4.3 percent of mule deer CWR within the project area would be directly 

impacted by development of well pads and access roads under the Proposed Action (Table 4.8-1). 

Assuming successful interim reclamation, as much as 6.1 percent of pronghorn and 6.6 percent of mule 

deer CWR within the project area would remain disturbed for the life of the project. 

The enhanced protections for big game would decrease the degree of risk associated with impacts of the 

Proposed Action (Section 4.8.3.1). Under this alternative, APDs that would affect pronghorn and mule 

deer crucial winter/yearlong range and migration corridors would be submitted with an overall 

development plan. The development plan would be submitted either for an individual lease or several 

leases. It should aim at reducing surface disturbance and disturbance associated with vehicle traffic and 

other human activity (Section 2.2.3). 

In addition, the following requirements would be implemented throughout mule deer and pronghorn 

crucial winter range or crucial winter/yearlong range and migration corridors: 

 Man camps would be prohibited on BLM land; 

 Noise-reduction technology would be required at compressor stations; and 

 Migration corridors would be monitored to determine which fences restrict movement. 

With these protection measures, the risk of big game displacement and stress from increased human 

activity would be expected to decrease (especially during winter) compared to the Proposed Action. Dustabatement programs would also help maintain forage palatability adjacent to roads. 

In addition to the measures discussed above, to reduce the human impact on big game in their CWR, this 

alternative contains surface-disturbance and population thresholds developed to maintain pronghorn and 

mule deer habitat and populations in the face of increasing development pressure. Surface-disturbance 

thresholds would reduce the impact of habitat removal and modification in CWR. The surface-disturbance 

thresholds are intended to reduce the amount of habitat disturbed and to mitigate disturbance through 

reclamation. When surface disturbance for natural gas access roads, pipelines, well pads or other facilities 

exceeds 5 percent of a lease within pronghorn or mule deer CWR, the BLM would: 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—WILDLIFE 

	 Evaluate reclamation success in the lease and review, approve and oversee the implementation of an 

Operators’ revised reclamation plan to ensure it addresses the reason for the failed reclamation. The 

calculated percentage disturbance would be adjusted downward for successful interim reclamation. 

 Conduct an assessment of the disturbance and determine if enhancement of CWR is needed at this 

time. If so, begin implementation. 

 Install remote monitoring at all well pads. 

If surface disturbance reached 10 percent of pronghorn or mule deer CWR in a lease, habitat 

improvement projects would be required in addition to the requirements above. The BLM would establish 

an interagency CD-C consultation group and consult with them to determine which projects would be 

beneficial. These projects could include, but would not be limited to: 

 Water developments. 

 Vegetation treatments such as herbicide treatments, seeding, prescribed burning, cutting/chopping 

for regeneration, planting shrubs or trees, fencing, establishing food plots, etc. 

If the WGFD were to express formal written concern that the herd within the project area was declining at 

an accelerated rate, all new APDs on leases within pronghorn and mule deer CWR in the CD-C project 

area would require an approved mitigation plan if the population decrease in those Herd Units were 

attributable in whole or in part to oil and gas development. The plan would include, but not be limited to: 

	 Evaluation of reclamation success in the lease and review, approve and oversee the implementation 

of an Operators’ revised reclamation plan to ensure it addresses the reason for the failed 

reclamation. 

	 Implementation of BLM-approved habitat-improvement projects such as water developments or 

vegetation treatments. (BLM may coordinate habitat improvement projects among multiple 

Operators.) New well pads would not be authorized without Operator participation in habitatimprovement projects. 

	 Limitation of the number of well pads to no more than four per section within CWR to maintain 

habitat effectiveness.
 

If the population status of a species were to change in the future, additional data would be collected and 

additional protective measures would be developed. 

With these protective measures in place the impact from habitat removal and modification in CWR is 

expected to decrease compared to the Proposed Action. Monitoring of population numbers would ensure 

that any population decline is identified early on and mitigation applied. This level of development within 

big game CWR, including migration routes, compounded by the current condition of CWR forage, along 

with the additional stress and displacement during the production phase, would exceed the WGFD 

definition of “High Impact” for both species, with the possibility of exceeding the WGFD definition of 

“Extreme Impact” and would thus exceed significance Criterion 2. 

Overlapping Big Game Crucial Winter Range. As in the discussion of both pronghorn and mule deer, 

the additional protections available under this alternative would likely reduce the impacts to overlapping 

big game CWR, including migratory routes, but would still exceed Criterion 3 and the WGFD definition 

of “High Impact,” with the possibility of exceeding the WGFD definition of “Extreme Impact.” 

Raptors. Under this alternative, no additional species-specific protections beyond those required by the 

RMP (timing and surface stipulations) and BMPs (Appendix C) would apply. Because of the buffers and 

restrictions on activity around raptor nests and the fact that most of the prey utilize habitat that can be 

reclaimed in a timely fashion, the impact from Alternative B is not expected to exceed the significance 

criteria. 

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Small Mammals and Neotropical Songbird Nests. Under this alternative, no additional species-specific 

protections beyond those required by the RMP (timing and surface stipulations), BMPs (Appendix C) 

and the Migratory Bird Treaty Act would apply. With the application of these mitigation measures and 

implementation of timely reclamation activities, it is anticipated that local population productivity would 

be maintained and the impact from Alternative B is not expected to exceed the significance criteria. 

Upland Game Birds. No enhanced protection measures would apply; however, the mourning dove is 

likely to benefit from protection measures under this alternative. Impacts to greater sage-grouse under this 

alternative are discussed in detail in Section 4.9.3.4. 

Fish. The Enhanced Resource Alternative Protections for the Muddy Creek Corridor/Watershed described 

in Section 2.2.3.4 could substantially reduce project impacts to fish. The sources of these reductions 

would include the following protections: 

	 For protection of amphibians and their habitats, avoidance of surface-disturbing and disruptive 

activities within 0.25 mile of Red Wash, springs, wells, and wetlands. The required avoidance 

distance would be further increased on perennial streams to 0.5 mile. Exceptions would only be 

granted by the BLM based on environmental analysis and site-specific engineering and mitigation 

plans. Only actions within areas that could not be avoided and that would provide protection for the 

resource identified would be approved. In-channel activities would be restricted to the low-flow 

period. 

	 Current monitoring on upper Muddy Creek would be extended to Lower Muddy Creek in the CD-C 

area. This requirement would bring lower Muddy Creek into conformance with the monitoring 

being done for upper Muddy Creek and other drainages within the Atlantic Rim project area. If 

results of the monitoring program showed impacts to sensitive fish habitat, the BLM and an 

interagency CD-C consultation group would determine whether habitat-improvement projects 

should be implemented. The projects could include, but would not be limited to, increasing the 

number of drainage features along roads, increasing in-stream cover for fish, and other measures as 

applicable. 

	 A monitoring plan for Bitter Creek watershed will be designed. 

The following requirements related to selenium and salinity for well locations and operations would also 

be implemented: 

 No surface discharge of produced waters within the Muddy Creek and Bitter Creek watersheds. 

 Line all reserve pits in the Muddy Creek and Bitter Creek watersheds. 

These protections, however, only apply to BLM land and only about 36 percent of Muddy Creek within 

the project area is on BLM land, while 51 percent and 13 percent are on private and state land, 

respectively. An unintentional consequence of these protections being applied only to BLM land could be 

to increase drilling activities on private and state land. Such development on private and State land along 

Muddy Creek could completely negate the enhanced resource protections on BLM land along Muddy 

Creek. To preclude this possibility, the Operators and the state should make a commitment to apply these 

same enhanced resource alternative protections to private and state land along Muddy Creek. Without this 

commitment, it is possible that the impacts to fish for this alternative would be the same as for the 

Proposed Action. 

4.8.3.4 Alternative C: Surface Disturbance Cap with High and Low Density Development 

Areas 

This alternative designates parts of the project area for high-density development—those areas that have 

seen the greatest natural-gas development to date (Map 2-1). Within the high-density development areas, 

a 60-acre cap would be placed on the amount of unreclaimed surface disturbance allowed at any one time 

in a section of public land. For the remainder of the project area—the low-density development areas— 

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the cap would be 30 acres per public land section. Once interim reclamation on the development is 

determined to be successful, the cap would be increased by the number of acres deemed to have achieved 

successful interim reclamation. 

Under Alternative C, the types of impacts to wildlife species and their habitats would be similar to those 

described for the Proposed Action (Section 4.8.3.1). The cap, however, places a limit on the amount of 

unreclaimed surface disturbance at any one time in a section of federal land. This requirement should 

encourage the use of directional drilling and enhanced reclamation practices. For this reason, the scope 

and intensity of impacts on wildlife and their habitat would be less. Maximum surface disturbance for this 

alternative is estimated to decrease by 4,245 acres in the short term to 42,955 acres, a 9-percent reduction 

from the Proposed Action. Long-term disturbance would decrease by 1,543 acres, to 17,318 acres. 

Because more wells would be drilled from directional well pads under this alternative, fewer well pads 

overall would be developed—an estimated 5,299 compared to the estimated 6,126 well locations of the 

Proposed Action, a reduction of about 13 percent. Therefore, fewer access roads would be developed and 

habitat fragmentation and other adverse impacts would be less extensive than for the Proposed Action. 

However, disruptive activities are expected to continue and may increase in high-density development 

areas, accompanied by associated adverse affects on population productivity and survival in localized 

areas, when compared to the Proposed Action. 

Pronghorn. Initially, an additional 3.3 percent of pronghorn CWR within the project area would be 

directly impacted by development of well pads and access roads under the Proposed Action (Table 4.8-

1). Assuming successful interim reclamation, approximately 6 percent of pronghorn CWR within the 

project area would remain disturbed for the life of the project. 

Of the estimated 90,310 acres of CWR and associated migratory routes in the project area (Map 3.8-2), 

30 percent would be in the high-density development area and 70 percent outside. Therefore, no more 

than 30 acres per section could be unreclaimed at any one time in the majority of pronghorn CWR. In the 

30 percent of pronghorn CWR located within the high-density development, no more than 60 acres per 

section could be unreclaimed at any one time. Due to the surface disturbance cap, more directional wells 

would be drilled, decreasing habitat fragmentation from that of the Proposed Action and also reducing the 

acreage of indirect impact to pronghorn, especially in the low-density areas. Since private and state lands 

would not be subject to the cap, surface disturbance in those sections would not be limited, so the benefits 

of less fragmentation may not be as prevalent at the landscape level. Impacts under this alternative are 

expected to be less than those of the Proposed Action and sufficient to avoid significance under Criterion 

2, provided disturbance is limited to 20 acres per square mile (the likely disturbance associated with a 

single multi-well pad). If that figure were exceeded, the impact could be significant. In addition, 

disruptive activities are expected to continue and may increase, in high-density areas, accompanied by 

associated adverse affects on population productivity and survival in localized areas, when compared to 

the Proposed Action. 

Mule Deer. There are 17,849 acres of mule deer CWR within the project area, located in the southeastern 

portion (Map 3.8-4). Of this acreage, approximately 25 percent is within the high-density development 

area and 75 percent outside. Initially, an additional 4.1 percent of mule deer CWR and associated 

migratory routes within the project area would be directly impacted by development of well pads and 

access roads under Alternative C (Table 4.8-2). Assuming successful interim reclamation, approximately 

6.4 percent of mule deer CWR within the project area would remain disturbed for the life of the project. 

Impacts under this alternative are expected to be less than those of the Proposed Action and sufficient to 

avoid significance under Criterion 2, provided disturbance is limited to 20 acres per square mile (the 

likely disturbance associated with a single multi-well pad). If that figure were exceeded, the impact could 

be significant. In addition, disruptive activities are expected to continue and may increase in high-density 

areas, accompanied by associated adverse affects on population productivity and survival in localized 

areas when compared to the Proposed Action. 

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Alternative C is expected to exceed significance Criterion 2 (substantial disruption or irreplaceable loss of 

vital and high-value habitats) and the WGFD definition of “High Impact” for pronghorn and mule deer 

CWR and associated migration routes in high-density development areas. 

Overlapping Big Game Crucial Winter Range. Impacts under this alternative are expected to be less 

than those of the Proposed Action and sufficient to avoid significance under Criterion 2, provided 

disturbance is limited to 20 acres per square mile (the likely disturbance associated with a single multiwell pad). If that figure were exceeded, the impact could be significant. However, disruptive activities are 

expected to continue and may increase if high-density development were to occur in CWR. 

Raptors, Small Mammals, Upland Game Birds, Neotropical Migratory Birds. In areas of low-density 

development, impacts to these species should be less than the Proposed Action since the amount of 

surface disturbance, both initial and long-term, would decrease. In high-density development areas 

impacts would likely be greater on some species when compared to the Proposed Action. For example, 

recent research (Gilbert and Chalfoun 2011) found that when natural gas well density reached more than 8 

wells per square kilometer (> 20 wells per square mile) the observed numbers of Brewer’s sparrow, sage 

sparrow, and vespers sparrow declined. In the same study, horned lark numbers increased while sage 

thrashers showed no effect as a result of high-density well development (Gilbert and Chalfoun 2011). 

The impact from Alternative C is expected to exceed the significance criteria in high-density areas; 

however, the application of the RMP general wildlife management action #13 (BLM 2008a, pg. 2-53), 

“Surface-disturbing activities and disruptive activities will be intensively managed. BMPs (Appendix 14 

and 15) will be applied to surface-disturbing and disruptive activities to maintain or enhance upland game 

bird species, neotropical and other migratory bird species, and their habitats,” may serve to reduce these 

impacts and thus the significance criteria may not be exceeded. 

Fish. Within the project area, only a small part of Muddy Creek would be located in the high-density area 

(Map 2-1). Most of Muddy Creek is in the low-density area. In addition, where Muddy Creek is within 

the high-density areas, it primarily flows through private land. Because surface disturbance would be 

capped at 30 acres per section in the low-density area and at 60 acres per section in the high-density area, 

impacts to fish in Muddy Creek derived from surface disturbance should be decreased compared with the 

Proposed Action. However, without the added types of protections for Muddy Creek discussed in Section 

4.8.3.3 for Alternative B, the types of impacts to fish would be similar to those for the Proposed Action, 

although the magnitude of impacts should be less. 

4.8.3.5 Alternative D: Directional Drilling 

Under Alternative D, the types of impacts to wildlife species and their habitats would be similar to those 

described for the Proposed Action (Section 4.8.3.1) though on a more localized level. This alternative 

requires that all future natural gas wells on federal mineral estate and surface be drilled from multi-well 

pads. In public land sections that have already had development, the enlargement of one existing well pad 

would be permitted as the multi-well pad for all future drilling in that section. No new roads or pipeline 

routes would be permitted in these leases. In sections in which there is no existing development, one new 

well pad would be permitted for all future development. One road and pipeline corridor on the lease or 

section would be permitted. The objective of this alternative is to minimize surface disturbance, thereby 

reducing habitat loss and wildlife disturbance. This alternative also reduces habitat fragmentation. Total 

surface disturbance for this alternative would decrease by 10,751 acres to 36,499, a reduction of about 23 

percent from the Proposed Action. Long-term disturbance is estimated to decrease by 3,908 acres to 

14,952 acres, a reduction of about 21 percent from the Proposed Action. 

Because more wells would be drilled from directional well pads under this alternative, fewer well pads 

overall would be developed—an estimated 4,032 compared to the estimated 6,126 well locations of the 

Proposed Action for a reduction of about 34 percent. Therefore, fewer access roads and pipelines would 

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be developed and habitat fragmentation and indirect impacts would be less extensive than for the 

Proposed Action. 

Pronghorn. Initially, an additional 3.0 percent of pronghorn CWR and associated migration routes within 

the project area would be directly impacted by development of well pads and access roads under 

Alternative D (Table 4.8-1). This is a decrease from the 3.6 percent increase in disturbance anticipated 

under the Proposed Action. As a result of the extended timeframe needed to fully restore the shrub 

component of the CWR, as much as 5.6 percent of pronghorn CWR within the project area would remain 

disturbed for the life of the project; however, various seral stages of shrub habitat would be available over 

the life of the project and would serve as pronghorn forage. 

Due to the multi-well pad requirement, fewer well pads would be constructed, decreasing habitat 

fragmentation as compared to the Proposed Action. Alternative D would also reduce the extent of indirect 

impacts to pronghorn, especially in the lower-density development areas. Since private and state lands 

would not be subject to the multi-well pad requirement, surface disturbance in those sections would not 

be limited, so the benefits of reduced habitat fragmentation may not be as evident at the landscape level. 

Impacts under this alternative are expected to be less than those of the Proposed Action and sufficient to 

avoid significance under Criterion 2; provided disturbance is limited to less than 20 acres per square mile, 

the impact would be classified as “Moderate” per the WGFD definition (WGFD 2010a). The application 

of mitigation (Timing Stipulations) precluding activity in crucial ranges and associated migration routes 

during the winter season should serve to minimize impacts to the species from these long-term/longduration well sites and their noise and enhanced activity levels. 

Mule Deer. An additional 3.7 percent of mule deer CWR and associated migration routes within the 

project area would be directly impacted by development of well pads and access roads under Alternative 

D (Table 4.8-2). Due to the extended timeframe needed to fully restore the shrub component of the CWR, 

approximately 6.0 percent of mule deer CWR within the project area would remain disturbed for the life 

of the project; however, various seral stages of shrub habitat would be available over the life of the 

project and would serve as mule deer forage. The impacts would be similar to those described for 

pronghorn above. However, a greater percentage of the Mule Deer CWR is outside of the checkerboard, 

so the landscape-scale benefits of this alternative should be greater for mule deer than for pronghorn. 

Impacts under this alternative are expected to be less than those of the Proposed Action, and sufficient to 

avoid significance under Criterion 2; provided disturbance is limited to less than 20 acres per square mile, 

the impact would be classified as “Moderate” per the WGFD (2010) definition. The application of 

mitigation (Timing Stipulations) precluding activity in crucial ranges and associated migration routes 

during the winter season should serve to minimize impacts to the species from these long-term/longduration well sites and their noise and enhanced activity levels. 

Overlapping Big Game Crucial Winter Range. Impacts under this alternative are expected to be less 

than those of the Proposed Action, and would avoid significance under Criterion 2 and meet the WGFD 

definition of “Moderate Impact” (WGFD 2010a), provided disturbance is limited to less than 20 acres per 

square mile. 

Raptors, Small Mammals, Upland Game Birds, and Neotropical Migratory Birds. Impacts to these 

species should be less than for the Proposed Action since the amount of surface disturbance, both initial 

and long-term, would decrease. Noise from drilling and completion activities occurring at long-duration 

multi-well pads could represent a localized negative impact to a sub-set of sensitive receptors (i.e. nesting 

raptors, sage-grouse) due to the increased period of time required for drilling at a single location. Reduced 

surface disturbance and habitat fragmentation resulting from multi-well pads comes with an increase in 

decibel level and frequency of that noise, as well as the extended period of time over which large haultruck activity would occur. However, application of the following RMP general wildlife management 

action #13 (BLM 2008a, p. 2-53) would also serve to provide habitat protection for small mammal 

species: “Surface-disturbing activities and disruptive activities will be intensively managed. BMPs 

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(Appendix 14 and 15) will be applied to surface-disturbing and disruptive activities to maintain or 

enhance upland game bird species, neotropical and other migratory bird species, and their habitats.” With 

the application of these mitigation measures, the impact from Alternative D is not expected to exceed the 

significance criteria. 

Fish. The types of impacts to fish for this alternative would be similar to those for the Proposed Action. 

Total surface disturbance for this alternative, however, would be about 23 percent lower than for the 

Proposed Action; therefore, the magnitude of impacts to fish should be proportionately less. 

4.8.3.6 Alternative E: No Action 

Under the No Action Alternative, there would be no new surface disturbance and no new impacts on 

wildlife habitat. Wildlife would continue to be affected by earlier habitat alterations, by human activity in 

the vicinity of natural gas production facilities, by traffic in the project area, and by diminished 

palatability of browse and forage caused by dust. 

4.8.4 Impact Summary 

The project, as proposed, would disturb and alter approximately 47,200 acres of wildlife habitat over the 

15-year project development phase, in addition to the 60,176 acres previously disturbed by natural gas 

and other development. Reclamation of disturbed areas should recover to grass-dominated habitats in one 

to several years, depending on precipitation and effectiveness of reclamation efforts. Shrub habitats would 

not reach pre-disturbance levels during the life of the project; however, a variety of shrub age classes 

would be available as forage and cover throughout the project area as reclaimed areas mature. Therefore, 

wildlife dependent on mature shrub habitats would be impacted most by habitat loss. In addition to the 

physical removal of habitat, disturbance during construction and production can displace or preclude 

wildlife use during all seasons. Timing restrictions for the critical times of year have been developed for 

the most sensitive species and are generally implemented during the development phase. During the 

production phase, the application of BMPs identified in Appendix 15 of the RMP (BLM 2008a) would 

work to alleviate impacts to the species. This would likely serve to reduce stress and help maintain animal 

condition and improve winter survival of the animals as they travel farther or are displaced to lowerquality range. Other impacts from natural gas development include habitat fragmentation, reduced 

availability and palatability of forage due to dust, and mortality from collision between vehicles and 

wildlife. 

The Proposed Action is expected to exceed significance under Criterion 2 (substantial disruption or 

irreplaceable loss of vital and high-value habitats) and the WGFD definition of “High Impact” for 

pronghorn and mule deer CWR and associated migration routes. Other species (raptors, small mammals, 

songbirds, and fish) should be protected sufficiently by the COAs, RMP requirements, and BMPs to 

avoid exceeding the significance level. 

Alternative A: 100-percent Vertical Drilling would affect an additional 14,496 acres of habitat 

compared to the Proposed Action. The impacts described above would be intensified under this 

alternative; Criterion 2 and the WGFD definition of “Extreme Impact” would likely be exceeded for 

pronghorn and mule deer CWR, migration routes, and overlapping crucial habitats. 

Alternative B: Enhanced Resource Protection was designed to reduce impacts of development on those 

species or habitats that are most vulnerable to an infill oil and gas project. There would be a slight 

reduction (1,684 acres, about 3.5 percent) in the amount of habitat disturbed under this alternative 

compared to the Proposed Action. Anticipated impacts to mule deer and pronghorn CWR and associated 

migration routes would be reduced compared to the Proposed Action through the application of additional 

mitigation requirements. That said, impacts to mule deer and pronghorn CWR and migration routes are 

expected to exceed significance under Criterion 2 and the meet the WGFD definition of “High Impact” 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—WILDLIFE 

(WGFD 2010a). Other wildlife species would also benefit from this alternative and its additional 

protection of the Muddy Creek watershed, riparian areas, and playas. 

Alternative C: Cap on Surface Disturbance, 60 or 30 Acres per Section seeks to reduce habitat 

disturbance and reward successful reclamation. This alternative is expected to impact 4,245 fewer acres 

than the Proposed Action. It should reduce the impacts to all species below those of the Proposed 

Alternative, but is still expected to exceed the level of significance under Criterion 2 for mule deer and 

pronghorn CWR. Anticipated impacts would meet the WGFD definition of “High” for both pronghorn 

and mule deer, as well as “High” for overlapping crucial ranges (WGFD 2010a), primarily in areas of 

high-density development. 

Alternative D: 100 Percent Directional Drilling is expected to reduce surface disturbance by 10,751 

acres (about 23 percent) compared to the Proposed Action. Impacts under this alternative are expected to 

be less than those of the Proposed Action, and sufficient to avoid significance under Criterion 2; provided 

disturbance is limited to less than 20 acres per square mile, the impact would be classified as “Moderate” 

per the WGFD (2010) definition. 

Alternative E: No Action is assumed to result in no new surface disturbance and no new impacts on 

wildlife habitat because no further natural gas development would occur within the CD-C project area. 

4.8.5 Unavoidable Adverse Impacts and Additional Mitigation Measures 

The amount of wildlife habitat would be unavoidably reduced on a short- to long-term basis as a result of 

the surface disturbance related to construction of well sites and associated facilities on public, state, and 

private lands within the CD-C project area. The quality and function of habitat would also be reduced due 

to intermediate- to long-term alterations in the vegetative composition of habitats and the continuing 

traffic and human presence associated with natural gas production activities. These impacts would be in 

addition to historical impacts from prior surface disturbance. Proposed and existing habitat alteration 

together would represent ten percent or more of the CD-C project area. The impacts on mule deer and 

pronghorn habitat are expected to exceed significance under Criterion 2—management actions that result 

in substantial disruption or irreplaceable loss of vital and high-value habitats—for the Proposed Action 

and all action alternatives except Alternative D. 

Application of additional mitigation measures such as those listed below, many of them found as 

elements of Alternative B, could work toward reducing the impacts of the Proposed Action and the action 

alternatives. In many circumstances the RFO is already requiring these mitigation measures as standard 

Conditions of Approval (COAs) (M. Read, pers. com., January 2012). 

 Minimizing human presence at well sites after they have been put into production by remote 

monitoring of project facilities and gating of roads; 

 Development planning for an entire lease or several leases; 

 Noise-reduction technology, such as hospital grade mufflers, sound walls or soundproof buildings, 

or adding silencers to cooling fans; 

 Monitoring of migration corridors to determine which fences restrict movement and fences 

modified to reduce impacts to migrating big game species; 

 Habitat improvement projects such as water developments and vegetation treatments; and 

 Training programs for field workers to raise their awareness of activities that cause stress to big 

game, times of day when collisions are most likely, and other programs as necessary. 

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4.9 SPECIAL STATUS SPECIES 

4.9.1 Introduction 

Special-status species are (1) those listed as Threatened or Endangered by the USFWS under the 

Endangered Species Act (ESA) of 1973 or those that are candidates or have been petitioned for listing and 

(2) those designated by the BLM State Director as sensitive (BLM 2010). Species are designated as 

sensitive if their numbers are declining so rapidly that ESA listing might be necessary, or if they have 

typically small or dispersed populations or inhabit unique habitats. 

Eight species listed by the USFWS as threatened, endangered, proposed, or candidate are present, or 

potentially are present, within or near the CD-C project area (USFWS 2010; Table 3.9-1). Two are 

mammals, and one is a bird. Four of the species are fish found downstream of the project area in the 

Colorado River system which may be impacted if water depletions occur or if environmental 

contaminants are increased within the system. One plant listed as USFWS-threatened (Ute ladies’-tresses) 

may occur within the project area 

Twenty-eight species that have been designated as sensitive by BLM are present or potentially present 

within or near the project area: eight mammals, 10 birds, two amphibians, four fish, and four plants 

(Table 3.9-3). 

A Biological Assessment (BA) will not be included in this draft document. Once a Preferred Alternative 

is selected, the BA will be finalized and sent to the USFWS for a Biological Opinion (BO). 

4.9.2 Management Objectives and Impact Significance Criteria 

The Rawlins RMP (BLM 2008a) management objectives for special status wildlife and fish species are 

the same as those presented for wildlife (Section 4.8.2). The RMP also defines the following impact 

significance criteria that are used in this document to assess the impacts associated with the Proposed 

Action and alternatives (BLM 2008b). Impacts to special status wildlife and fish species would be 

considered significant if any of the following were to occur: 

 Substantial loss of the biological integrity and habitat function of terrestrial and aquatic ecosystems 

that would make a species eligible for listing under the ESA. 

 Decreased viability or increased mortality of Threatened, Endangered, Proposed, and/or Candidate 

species, or adverse alteration of their critical habitats. 

	 Substantial loss of habitat function or disruption of life-history requirements of special status 

species that would preclude improvement of their status. Habitat function means the arrangement of 

habitat features and the capability of those features to sustain species, populations, and diversity of 

wildlife over time (WGFD 2010a). 

Impacts to special status plant species would be considered significant if any of the following were to 

occur: 

	 Any action or event that would remove a community’s unique attributes or ability to support other 

resource values within the planning period, or if corrective actions were beyond the scope of the 

RMP. 

 The viability of protected plant species is jeopardized, with little likelihood of reestablishment after 

disturbance, or actions result in the need to list a species under ESA. 

 Actions that have the potential to remove sensitive plant species or substantially alter the habitat’s 

ability to support the species. 

Additionally, the RFO has determined that the following impact significance criterion should be included 

for this project: 

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 Actions that preclude attainment of conservation goals, as stated in conservation plans and strategies 

for special status species. 

The degree of impact that constitutes “substantial” loss of habitat or disruption of life-history 

requirements is quantified for some wildlife species in the habitat and population thresholds described in 

the Enhanced Resource Protection Alternative (Alternative B). 

4.9.3 Direct and Indirect Impacts 

4.9.3.1 Proposed Action 

Habitats directly and indirectly affected by the proposed project are the same as those discussed for 

general wildlife (Section 4.8.3). 

Standard environmental protection measures prescribed as Conditions of Approval (COAs) or used as 

BMPs (Appendix C) would be implemented under the Proposed Action and all alternatives. The Wildlife 

Monitoring and Protection Plan (Appendix I) would be followed to detect, prevent, and reduce impacts to 

wildlife and fish species throughout the life of the project. These protective and mitigative measures 

would serve to minimize the impacts of development activity on public land managed by the BLM. 

However, the measures do not apply to private and state lands, which encompass 46 percent of the project 

area. Therefore, the effectiveness of the mitigation is limited when considering a landscape approach, 

particularly in the checkerboard section of the project area. 

Threatened, Endangered, Proposed or Candidate Wildlife Species 

Habitat for Canada lynx is not found in the project area and their potential occurrence is described as 

Very Unlikely (Table 3.9-3). This species will not be further addressed in this document. 

Black-footed ferret. The presence of black-footed ferret in the project area is very unlikely (see Section 

3.9.1.1). The Proposed Action would likely disturb colonies of white-tailed prairie dogs, which are the 

black-footed ferret’s primary habitat and prey source in this area. Surveys for black-footed ferrets may be 

required before ground-disturbing activities within mapped prairie-dog colonies located in the Continental 

Divide, Dad, and Desolation Flats non-block clearance areas. The remaining white-tailed prairie-dog 

colonies within the CD-C project area are within the USFWS designated block clearance area, where 

surveys for black-footed ferrets are no longer warranted. The Proposed Action is not expected to exceed 

the impact significance criteria for black-footed ferret populations. 

Greater sage-grouse. The impacts with the potential for the greatest negative effects to greater sagegrouse populations include: loss of nesting or brood-rearing habitat, displacement or additional stress due 

to increased human activities, excessive noise levels proximal to occupied leks, removal or modification 

of severe winter habitats, and increased predation due to an increased number of roosting sites for raptors 

on power poles and other man-made structures. 

Approximately 60 percent of the CD-C project area is comprised of sagebrush and other mesic shrubdominated vegetative classes, which represent identified greater sage-grouse nesting habitat, as defined by 

the RFO (Map 3.9-2). Recovery of shrubs in locations that have been disturbed by development to predisturbance levels would not occur during the life of the project. However, younger age classes of 

sagebrush with grass and forb components may serve as nesting and brood-rearing habitat for grouse. 

Populations have persisted in many areas where energy development is ongoing, yet research has shown 

that development can influence declines in lek occupancy, lek attendance, and possibly in population 

persistence (Braun et al. 2002, Aldridge and Boyce 2007, Harju et al. 2010, Walker et al. 2007). Sagegrouse may repopulate an area following energy development, but may not attain population levels that 

occurred before development (Braun 1998). Likelihood of abandonment is higher when nests are 

disturbed early in the incubation period (Remington and Braun 1991). 

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In the generally accepted body of literature, the following are potential sources of indirect impact to 

greater sage-grouse and their habitats, all of which could lead to lower productivity and long-term decline 

in the population of this species in the project area (WGFD 2010a): 

 Habitat loss resulting from dust settling on vegetation (Section 4.6) and reducing the palatability 

and production of forbs and shrubs used by grouse. 

 Visual intimidation from high-profile structures. 

	 Potential loss of sagebrush and understory due to over-browsing or grazing by wild ungulates, 

livestock, and wild horses on ranges shared with grouse, reducing quality and abundance of nesting, 

brood-rearing and winter habitats, as well as forage. 

	 In areas of Extreme Impact (more than 3 well pad locations or 60 acres of disturbance per square 

mile within 2 miles of an occupied lek in non-core population areas; WGFD 2010a), as 

development becomes more intense, the impact zones surrounding each well pad, production 

facility, and road corridor begin to overlap, thereby reducing habitat effectiveness over much larger, 

contiguous areas. Human, equipment, and vehicular activity and noise impacts are also more 

frequent and intensive (WGFD 2010a). 

 Noise levels interfere with bird communication during mating periods resulting in lower bird 

attendance at leks. 

 Disruptive human activities alter normal bird behavior, increase nest abandonment, and may 

displace birds into less-desirable habitats. 

 Construction of facilities and roads creates a long-term loss of grouse habitat and increases 

fragmentation of remaining habitat. 

 Increased predation by raptors and corvids due to facilities such as well houses, compressor stations, 

and above-ground power lines serving as perches. 

 Roads may also serve as travel corridors for some predators. 

Refer to Section 3.9.1.1, Greater sage-grouse, for a complete discussion of the protective measures in 

place throughout the project area for the conservation of greater sage-grouse and its seasonal habitats. The 

conservation strategy for greater sage-grouse continues to evolve and the requirements that would be 

applied to proposed activities in sage-grouse habitat will change similarly. Map 3.9-2 shows the core and 

non-core sage-grouse population areas within and near the project area. Fifty-four of the project area’s 

leks are in non-core areas and 31 are in state-designated core areas. 

The Proposed Action and alternatives have been analyzed relative to the requirements of IM WY-2012­

019 (BLM 2012c) and the national IM 2012-043 (BLM 2012b) which impose limits for surfacedisturbing and disruptive activities in sage-grouse core and non-core areas. The conservation guidelines 

provided in the WGFD Recommendation for Development of Oil and Gas Resources within Important 

Wildlife Habitats (WGFD 2010a) were also considered. IM WY-2012-019 (BLM 2012c) calls for 

consideration and evaluation of greater sage-grouse conservation measures that are the same as or in some 

cases more stringent than those of the Rawlins RMP. The Rawlins RMP prohibits surface-disturbing 

activity on and within 0.25 mile of the perimeter of an occupied lek year-round in non-core areas and 

increases the distance to 0.6 of a mile from the perimeter of an occupied lek in designated core. The IM 

calls for consideration of the same. The RMP has an associated timing limit on disruptive activities within 

0.25 miles of an occupied lek from 6:00 pm to 9:00 am from March 1 to May 20; IM WY-2012-019 calls 

for consideration of extending the distance of that timing stipulation to 0.6 mile in core areas. Under the 

IM, avoidance of surface-disturbing and/or disruptive activities within all core area nesting and early 

brood-rearing habitat (Map 3.9-2) from March 1 to July 15 (timing period as found in the RMP) is to be 

considered. The RMP applies that same level of protection to identified nesting and early brood-rearing 

habitat, regardless of distance from the lek, in non-core areas from March 1 to July 15 (M. Read, 

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pers.com. February 2012). BLM is currently working to amend the RMP as it relates to greater sagegrouse conservation (BLM 2010c). 

IM WY-2012-019 also includes a density goal for core areas that requires maintenance of sagebrush 

communities by maintaining or reducing the existing level of density of energy production and/or 

transmission structures on the landscape, or not exceeding one energy production location and/or 

transmission structure per 640 acres. The one location and cumulative value of existing disturbances in 

the area would not exceed 5 percent (32 acres) of sagebrush habitat within those same 640 acres. 

IM WY-2012-019 provides protection for mapped or modeled winter habitat/concentration areas from 

surface-disturbing activities from November 15 to March 14. Activities would be allowed outside this 

period and winter habitat could still be affected or removed by surface disturbance outside the timing 

limitation. Loss of this habitat could lead to lower productivity and long-term decline in the population of 

this species. As winter concentration areas are identified and mapped in the CD-C project area BLM 

would apply seasonal stipulations and habitat protection measures (BLM 2008a and 2012b). 

Habitat loss would continue around leks outside the 0.25-mile protected buffer in non-core areas and the 

0.6-mile buffer in core areas, including within the buffer zones outside the seasonal protection. In noncore areas, application of the standard for avoidance of potential nesting and brood-rearing habitat as well 

as the BLM standard COAs, BMPs (Appendix C), Timing Limitations, and Mitigation (Appendix I) 

would reduce the impact to sage-grouse but impact to those populations (dust, noise, and continued 

human presence during the drilling and production phase) would still be anticipated. It is expected that 

greater than three wells or 60 acres of disturbance per square mile could occur within the 2-mile radius of 

some non-core leks but not all. In some areas this level of disturbance has already been exceeded; this 

would be considered an “Extreme Impact” relative to those individual leks (WGFD 2010). In core 

population areas, habitat disturbance would be limited to less than 5 percent of a 640-acre section or one 

disruption (i.e. well location) per section (square mile), averaged over the specific sage-grouse impact 

(i.e. DDCT) analysis area. Provided the protections for greater sage-grouse found in IM WY-2012-019 

and the Rawlins RMP are applied, it is not expected that the significance criteria would be exceeded in 

core areas but localized exceedance of Criteria 1, 2, and 4 could occur in non-core areas. Sage-grouse 

populations in non-core areas may experience localized substantial loss of habitat, biological integrity or 

function, decreased viability or increased mortality or substantial disruption of life-history requirements. 

By definition non-core areas are not “critical habitats;” therefore Criteria 3 would not be exceeded. 

Threatened and Endangered Fish Species 

Four federally Endangered fish species may occur as downstream residents of the Colorado River system: 

Colorado pikeminnow (Ptychocheilus lucius), bonytail (Gila elegans), humpback chub (Gila cypha), 

and razorback sucker (Xyrauchen texanus) (USFWS 2003). Suitable habitat for these species does exist 

downstream of the project area in the Little Snake, Yampa, and Green Rivers. Because the Colorado 

pikeminnow is found in the Little Snake River, it could migrate into Muddy Creek. Muddy Creek, 

however, is not considered suitable habitat for this species. The action alternatives are not expected to 

affect this habitat, provided that mitigation measures for water resources and soils outlined in this 

document are implemented. Although they currently exist only downstream of the project area, water 

draining from the project area affects the downstream habitat for these species. Under the Proposed 

Action, the sources of risks to these fish species are water depletions, discharges of produced water, and 

spills of toxic materials. 

Water Depletions. The Upper Colorado River Endangered Fish Recovery Program is a partnership 

working to recover the endangered fish of the Upper Colorado River Basin. The goal of recovery is to 

achieve natural, self-sustaining populations of the endangered fish so that they no longer require 

protection under the ESA. Under the Recovery and Implementation Program (RIP) for Endangered Fish 

Species in the Upper Colorado River Basin, “any water depletions from tributary waters within the 

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Colorado River drainage are considered as jeopardizing the continued existence of these fish.” Tributary 

water is defined as water that contributes to instream flow habitat. Depletion is defined as water which 

would contribute to the river flow if not intercepted and removed from the system. 

The FWS has determined that progress made under the RIP has been sufficient to merit a waiver of the 

depletion fee, which helps fund the RIP, for depletions of 100 acre-feet per year or less (Memorandum 

dated March 9, 1995 to Assistant Regional Director, Ecological Services, Region 6, from Regional 

Director 6, “Intra-Service Section 7 Consultation for Elimination of Fees for Water Depletions of 100 

acre-feet or Less from the Upper Colorado River Basin”). The Proposed Action, however, may deplete an 

average of 510 acre-feet of water per year (Section 4.4.4.1) and therefore a one-time depletion fee of 

approximately $20 per acre foot may be required. The figure of 510 acre-feet is the amount of water 

estimated to be withdrawn from aquifers in the Wasatch formation that may have contact with and 

contribute to the Little Snake River and its tributaries, including Muddy Creek. The extent to which the 

groundwater withdrawals constitute a depletion and any depletion fee will be determined in consultation 

between BLM and FWS before the Final CD-C EIS. 

Discharges of Produced Water and Spills of Toxic Chemicals. Produced water from the project area 

would not be discharged to Muddy Creek within the Little Snake River drainage; therefore, producedwater discharges will not pose a risk to these species. Accidental releases (e.g., spills) of toxic chemicals 

also could occur. However, accidental releases of toxic chemicals should become highly diluted before 

they would reach any downstream waters where these species occur; consequently, the risks from such 

occurrences are negligible (BLM 2007). For any future proposals involving CBNG, the proposed 

treatment and disposal of produced water will be analyzed in a separate NEPA document. 

Threatened and Endangered Plant Species 

The USFWS (2002) determined that the threatened Ute ladies’-tresses (Spiranthes diluvialis) may be 

present within the CD-C project area. However, because extensive surveys failed to document the 

presence of Ute ladies’-tresses within the project area, impacts to this plant are not anticipated. The 

possible presence of this federally listed plant species on public lands would be determined by the 

presence of appropriate riparian habitat. The application of the COA requiring avoidance of riparian areas 

by 500 feet serves to protect this species. In the unlikely event that the species is found within the project 

area, potential impacts to the species on public land would be addressed through consultation with the 

USFWS. In particular, those sites would be avoided to prevent any impacts. Therefore, decreased viability 

or increased mortality of Threatened, Endangered, Proposed, and/or Candidate plant species or adverse 

alteration of their critical habitats, if identified, on public lands within the project area would not occur 

with implementation of the Proposed Action. Because the likely presence of this species on private or 

state lands is low, the likelihood of direct impacts on those lands is also low. 

Sensitive Wildlife Species 

The following sensitive wildlife species have not been found within the project area and would likely not 

be impacted by the project: black-tailed prairie dog, fringed myotis, long-eared myotis, spotted bat, 

Townsend’s big-eared bat, Baird’s sparrow, Columbian sharp-tailed grouse, northern goshawk, peregrine 

falcon, and boreal toad. These species will not be discussed further. Nevertheless, should populations be 

found, mitigation would be applied to avoid disruption of habitat function or of life history requirements. 

Species that may be affected by the Proposed Action are discussed below. 

Sensitive Mammal Species 

Fringed myotis, long-eared myotis, spotted bat, and Townsend’s big-eared bat have the potential to 

occur in the project area even though their preferred roosting and hibernation habitats are not found in the 

project area; however, equipment stack caps would be required as a mitigation for these species in an 

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effort to preclude incidental roosting. No other adverse effects are anticipated at this time, and Criterion 2 

would not be exceeded. 

Pygmy rabbits are patchily distributed throughout the project area (WYNDD 2007, HWA unpublished 

data). The intensity of development associated with implementation of the Proposed Action would likely 

result in direct disturbance of some portions of pygmy rabbit habitat and burrow systems. The RFO has a 

survey and avoidance policy for pygmy rabbit burrow systems. Therefore, direct impacts to pygmy 

rabbits, in the form of lost burrows and foraging habitat, are not expected to exceed the impact 

significance criteria. 

Swift foxes have been documented within the project area in the past; however, sightings in the area have 

not occurred in recent years. The intensity of development associated with implementation of the 

Proposed Action would likely result in direct disturbance to some suitable foraging habitat. Should 

populations be found, mitigation would be developed to protect them. Therefore, impacts are not expected 

to exceed the impact significance criteria. 

White-tailed prairie-dog colonies covering approximately 8,818 acres have been mapped within the 

project area to date (BLM unpublished data, HWA unpublished data). The Rawlins RMP requires that 

development avoid prairie-dog colonies whenever possible. The intensity of development associated with 

implementation of the Proposed Action would likely result in direct disturbance to some portions of these 

prairie-dog colonies. Direct impacts to prairie dogs, in the form of lost burrows and foraging habitat, are 

not expected to exceed the impact significance criteria. 

Wyoming pocket gophers are found within the project area. This was established by trapping efforts in 

2008–2010 (WYNDD unpublished data, HWA unpublished data). Based on those trapping efforts, the 

availability of suitable habitat, and the known distribution of the species, Wyoming pocket gophers are 

likely to be found in additional areas of suitable habitat within the project area. The BLM requires sitespecific surveys to determine if a project proposal should be relocated in an effort to avoid Wyoming 

pocket gopher mounds whenever possible. Therefore, impacts are not expected to exceed the impact 

significance criteria. 

Sensitive Bird Species 

Bald eagles have been observed within the project area primarily from November through March (WGFD 

2006, HWA unpublished data). No bald eagle nests or nesting habitat occur within the area, and the 

nearest potential nesting habitat is found along the Little Snake River, approximately 9 miles south of the 

project area. Bald eagles may forage within the project area during the winter months because of carrion 

associated with pronghorn, mule deer, and elk winter ranges. The potential for vehicle-animal collisions 

would increase as a result of greater vehicle traffic associated with the project. Because bald eagles 

commonly feed on carrion, particularly during the winter months, the presence of road-killed wildlife on 

and adjacent to the access roads is an attractant. Eagles feeding on these carcasses are in danger of being 

struck by moving vehicles. However, such occurrences would be rare and effects on the population are 

not expected to exceed the impact significance criteria. 

Brewer’s sparrow, loggerhead shrike, sage sparrow, and sage thrasher are the predominant shrubdependent songbirds that occur within the project area (WGFD 2006, WYNDD 2007, HWA unpublished 

data). In addition to the removal of habitat, activities under the Proposed Action may displace birds to 

lower-quality habitats, which could lead to a reduction in reproduction rates or an increase in predation. 

Recent research (Gilbert and Chalfoun 2011) found that when natural gas well density reached more than 

eight wells per square kilometer (more than 20 wells per square mile) the observed numbers of Brewer’s 

sparrow, sage sparrow, and vespers sparrow declined. In the same study horned lark numbers increased 

while sage thrashers showed no effect as a result of high-density well development (Gilbert and Chalfoun 

2011). 

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Burrowing owls are found throughout the project area (WGFD 2006, WYNDD 2007, BLM unpublished 

data). Surveys for this species should be conducted before construction in prairie-dog colonies during the 

owl breeding/nesting season. If nesting owls are found, the same measures used for protection of other 

raptor species (Appendix I) will be applied. Given these precautionary measures, the Proposed Action is 

not expected to exceed the impact significance criteria for this species population. 

Ferruginous hawks are the most abundant raptor species nesting within the project area (BLM 

unpublished data). The primary impact to ferruginous hawks from project activities is disturbance during 

nesting, which could result in reproductive failure. This impact would be mitigated by implementing 

measures in Appendix C, such as no surface occupancy (i.e. well locations, roads, ancillary facilities, or 

other surface structures) year-round within 1,200 feet of a ferruginous hawk nest and a seasonal 

restriction on surface disturbing and other disruptive activity from March 1 to July 31 within 1 mile of a 

ferruginous hawk nest. Nests located near private or state surface in the checkerboard would not benefit 

from the entire 1-mile seasonal buffer zone for nesting/foraging ferruginous hawks. It is difficult to 

determine if this would exceed Criterion 4 in this case because other factors such as topography could 

decrease the size of the needed buffer around nests, but the impacts are not expected to exceed the 

criterion. 

Long-billed curlew is an uncommon summer resident, but may be locally common in suitable habitat 

(WGFD 2004a). The long-billed curlew has been recorded once within the project area (WGFD 2007) 

and is not expected to nest within the area due to lack of habitat. No significant impacts to this species are 

expected with implementation of the Proposed Action. 

Mountain plover. The impacts with the potential for the greatest effects to mountain plover populations 

include: loss of nesting habitat, displacement or additional stress due to increased human activities, and 

increased potential for vehicular collisions due to higher traffic levels on existing and new roads. 

Mountain plover breed in suitable habitat throughout the project area (WGFD 2007, BLM unpublished 

data, HWA unpublished data). Approximately 342,393 acres of occupied or potential mountain plover 

nesting habitat have been mapped, comprising approximately 32 percent of the project area (Map 3.9-4; 

HWA unpublished data). A substantial portion of this nesting habitat would be disturbed with 

implementation of the Proposed Action. Impacts of displacement or additional stress from increased 

human activities should be minimized by avoiding construction activities in potential plover nesting 

habitat during the nesting period from April 10 to July 10, unless surveys show that no birds were found. 

Mountain plovers tend to use the same nesting areas from year to year (Dinsmore 2003), but the exact 

nest locations change. They often nest near roads and well sites (Manning and White 2001), feed on or 

near roads, and use roads as travel corridors (USFWS 1999), all of which make them susceptible to being 

struck by vehicles. In occupied habitat, BLM guidelines call for speed and traffic volume controls during 

the brood-rearing period. This may modify work schedules and shift changes during the most likely time 

for plovers to be on the road (Appendix 16 to the RMP). Following drilling and well-completion 

operations, noise levels, vehicle traffic, and human activity would be reduced. As a result, plovers might 

acclimate to the well pad production facilities and use habitats immediately adjacent to such sites. With 

the COAs and BMPs (Appendix C) and the Wildlife Monitoring and Protection Plan (Appendix I), the 

impact of the Proposed Action on mountain plover populations would likely not exceed the impact 

significance criteria. 

Trumpeter swans and white-faced ibis are uncommon in the project area and are always associated with 

wetland habitats. Both species have been observed within the project area during migration on only a few 

occasions (WGFD 2006, WYNDD 2007). Except for a few areas along Muddy Creek, wetlands are very 

limited within the project area. The Proposed Action is not expected to exceed the impact significance 

criteria because development would not occur within 500 feet of riparian and wetland habitats. 

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Sensitive Amphibian Species 

Great Basin spadefoot have been documented within the project area (WGFD 2006, WYNDD 2007) and 

occur within sagebrush communities. The intensity of development associated with implementation of the 

Proposed Action would likely result in direct disturbance to suitable breeding habitat. Development 

would not be permitted within 500 feet of riparian and wetland habitats; however, and with this 

protection, significant impacts are not expected. 

Northern leopard frog sightings have been documented in all counties of Wyoming and this species has 

been documented in the project area. Provided that measures are taken to avoid disturbance and 

contamination of perennial water sources (Section 4.4), impacts from the Proposed Action are not 

expected to exceed the impact significance criteria because development would not occur within 500 feet 

of riparian and wetland habitats. 

Sensitive Fish Species 

Sources of risks to sensitive fish species are (1) increases in suspended sediments and sedimentation, (2) 

produced-water discharges, and (3) spills of toxic materials. For any future proposals involving CBNG, 

the proposed treatment and disposal of produced water will be analyzed in a separate NEPA document. 

Increases in Suspended Sediments and Sedimentation. Research conducted during the summer and fall 

of 2003 and 2004 within the upper Muddy Creek watershed, including the project area, found the two 

most consistent habitat associations among sub-adult and adult roundtail chubs, bluehead suckers, and 

flannelmouth suckers to be positive associations with both rock substrates and deep pools (Figures 4.9-1 

and 4.9-2; Bower 2005). Under the Proposed Action, the primary impacts to these two habitat features 

are (1) sedimentation from new construction and project-related land disturbance resulting in decreased 

availability of rock substrates, and (2) alteration of local hydrologic conditions by new road construction 

that could lead to sedimentation and channel adjustments resulting in a loss of deep pool habitats. 

Additionally, fragmentation of aquatic habitats, if any project-related road crossings of Muddy Creek are 

constructed, could limit access to required habitats or block fish migration. 

The impact of new roads and other facilities on fish habitats can be divided into three categories: 

construction, presence, and urbanization (Angermeyer et al. 2004). During the construction phase, prior to 

interim reclamation, erosion of soils exposed during earth-moving activities accelerates fine-sediment 

loading in stream channels. Though the biological effects of sedimentation include a variety of ecological 

interactions (Waters 1995), sedimentation can act to shift habitat structure such as channel depth, pool-toriffle ratio, percent fines in substrates, and cover availability (Angermeyer et al. 2004). This sediment can 

extend miles downstream of the construction site and persist in stream channels for years (Angermeyer et 

al. 2004). 

During the presence phase, impacts are primarily associated with the interception of shallow groundwater 

flow paths by roads. Water is frequently diverted along the roadway and routed to surface-water drainage 

networks at drainage crossings. This can, in turn, alter the timing, routing, and magnitude of runoff, 

triggering geomorphic adjustments through erosion by channel incision, new gully or channel-head 

formation, or slumping and debris flows (Figure 4.9-1; see review in Trombulak and Frissel 2000). 

Channel incision occurs when the base elevation of the stream channel adjusts to account for an alteration 

of geomorphic parameters such as sediment supply, flow volume, or channel roughness (e.g., riparian 

vegetation). Channel incision has been shown to simplify channel geometry and result in the loss of pool 

habitat (Shields et al. 1994). Project-related crossings of Muddy Creek would be required to pass fish and 

would be mitigated as outlined in the Rawlins RMP. The RMP requires that any road crossing of a stream 

that may potentially support fish for a portion of the year must be constructed to allow fish passage. 

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Figure 4.9-1. Relative abundance of two length groups of three species within the upper Muddy Creek 

watershed as a function of the prevalence of rock substrates at the reach scale from 

Bower (2005). Plots were generated using the averaged multi-model linear-regression function for both 

length groups of the three species. 

Figure 4.9-2. Relative abundance of two length groups of three species within the upper Muddy Creek 

watershed as a function of maximum channel unit depth from Bower (2005). Plots were 

generated using the averaged multi-model linear-regression function for both length groups of the three 

species above minimum depth thresholds. 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—SPECIAL STATUS SPECIES 

Figure 4.9-3. Example of erosion resulting from 

concentration of surface runoff at 

drainage crossings 

In the case of the Proposed Action, the effects 

of urbanization are thought to include the 

detrimental effects of exotic species 

introduction and increased human presence 

within the project area. Roads provide 

dispersal mechanisms for a variety of exotic 

upland and riparian plant species. Of 

particular concern is the spread of tamarisk 

(Tamarix spp., also known as salt cedar) 

within the upper Muddy Creek watershed. 

This exotic species has been shown to displace 

native riparian vegetation while consuming a 

greater volume of water, resulting in reduced 

water tables and suitability of aquatic habitats 

(Graf 1978). Tamarisk is currently known to 

exist in portions of the project area and its 

spread is likely a result of dispersal via 

roadways. Increased human uses of the area 

are also likely to increase the probability of 

unsanctioned, illegal, and unintentional 

introductions of exotic fishes and other aquatic 

organisms. These introductions have been cited as one of the major threats to fresh-water biodiversity 

(Allan and Flecker 1993) and warrant careful consideration given the detrimental effects of exotic fishes 

on native Colorado River Basin fishes present within the upper Muddy Creek watershed. 

Stream fishes require habitats for spawning, feeding, rearing, and refuge. The spatial heterogeneity and 

connectivity of the stream system can necessitate the movement of fishes among these habitats in order to 

complete their life-cycles (Schlosser 1995). Interruption of movement among required habitats by road 

crossings can have demographic effects, decreasing population viability (Trombulak and Frissel 2000, 

Gibson et al. 2005). The distributions of the three target species during the summer and fall of 2003 

suggest several implications of habitat fragmentation with regard to access to refuge habitats and 

subsequent ability to recolonize adjacent reaches (Bower 2005). Additionally, movements of the three 

species observed during 2005 suggests that required habitats exist in spatially distinct portions of the 

watershed, thus requiring movement of individuals in order to complete their life history requirements 

(Compton 2007). Eighty-acre spacing of well locations, typical in the high-development parts of the 

project area, could result in a road density of up to 2.5 mi/mi2

 within the portion of the project along 

Muddy Creek, including new road construction. Additionally, crossings of Muddy Creek may occur as a 

result of the Proposed Action, although the number and specific locations of these crossings have not yet 

been determined. Eighty-acre spacing would result in significance based on Criterion 2. 

Research within the Little Robbers Gulch drainage has demonstrated the effects of roads, natural gas drill 

pads, and pipelines on sediment production and runoff (Wollmer 1994). This work examined the effect of 

road densities of 2 mi/mi2

, including associated well pad and pipeline facilities, on local sediment 

production and runoff. A net increase of 1 percent in local sediment production and 0.3 percent in local 

runoff was found when compared to unaltered rangeland sites. Although this work helps to identify the 

potentially limited extent of local erosion caused by roads, the study did not address the effects of flow 

interception which can lead to altered runoff timing, routes, and magnitudes. It is these hydrologic 

alterations that are most likely to result in geomorphic adjustments through erosion, causing 

sedimentation or loss of habitat features such as deep pools. 

Increased sediment delivery to stream-bottoms can embed gravels and reduce spawning success via 

decreased embryo survival fill in rearing pools, and reduce complexity of the habitat in stream channels 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—SPECIAL STATUS SPECIES 

(Magee et al. 1996). Deposition of sediment can also decrease populations and species composition of 

aquatic macroinvertebrates that are highly dependent on interstitial spaces for different life stages. These 

community changes can be detrimental to fisheries that depend on macroinvertebrates as primary food 

supplies and can change the abundance and diversity of the fish population. Loss of these stream 

attributes would threaten the persistence of BLM sensitive fish species. 

In addition to project activities that cause surface disturbance, a major source of sediment input to streams 

in the project area is wind erosion. Much of the area along Muddy Creek within the project area has a 

moderate to high wind-erosion potential (Map 3.3-2). A moderate potential for wind erosion exists for 80 

percent of the total project area or 859,633 acres (Table 3.3-1). 

Discharges of Produced Water. Produced water from the project area would not be discharged to 

Muddy Creek within the Little Snake River drainage; therefore, produced-water discharges would not 

pose a risk to these species 

Spills of Toxic Materials. Accidental releases of toxic materials to Muddy Creek would pose a risk to 

sensitive fish populations. The probability of spills occurring is unknown, but their consequences could 

be significant if spills occurred. One spill could kill most of the fish in lower Muddy Creek. 

Because of the limited distribution in Wyoming and other states of the three sensitive fish species found 

in the project area—the roundtail chub, the bluehead sucker, and the flannelmouth sucker—the effects of 

the Proposed Action are considered to be significant. The disturbance created by new roads and facilities 

would increase suspended sediments and sedimentation, altering habitat features found to be important to 

the fishes and fragmenting that habitat. These effects would be exacerbated by any accidental discharge of 

produced water or spills of toxic materials into the watershed. The significant impact on the habitat of the 

species within the project area may preclude improvement of their status as prescribed in the Range-wide 

Conservation Agreement for Bluehead Suckers, Flannelmouth Suckers, and Roundtail Chubs. This would 

be contrary to Criterion 4. Eighty-acre spacing of wells would result in significance based on Criterion 2. 

Sensitive Plant Species 

The presence of sensitive plant species on public lands would be determined by soil surveys or rare-plant 

surveys prior to site development. Avoidance and best management practices identified on a case-by-case 

basis would then be applied to proposed surface-disturbing activities to protect or enhance sensitive plant 

species and their habitats (BLM 2008a, p. 2-47). Therefore, decreased viability or increased mortality of 

the Cedar Rim thistle, Gibben’s beardtongue, Meadow milkvetch, and persistent sepal yellowcress—or 

adverse alteration of their critical habitats—would not occur on public lands within the CD-C project area 

with implementation of the Proposed Action. Meadow milkvetch and persistent sepal yellowcress would 

be further protected on public lands because development would not be permitted within 500 feet of 

riparian and wetland habitats (BLM 2008a). Cedar Rim thistle and Gibben’s beardtongue could be 

impacted if their habitats are disturbed by development activity. BLM-designated sensitive plant species 

are likely to occur on private and state lands within the project area; however, surveys to determine their 

presence or to locate their habitat would not be required nor would avoidance or other mitigating activity. 

The impact on private and state lands is thus not known. 

Indirect impacts to special status plants and/or their habitats could occur as a result of several natural gas 

development activities. New invasive weed infestations near well pad locations and other surface 

disturbances could spread into occupied special status plant species habitat. The effects of fugitive dust 

created by new access roads and increased vehicle activity could have a detrimental effect on the vigor 

and survival of special status plant species. Unauthorized off-road vehicle use could negatively impact 

special status plant species, either by direct destruction or by alteration of their habitats. Indirect impacts 

to BLM-designated sensitive plants on public lands are anticipated to be either minimal or none due to the 

required 500-foot setback from riparian areas and the use of soil survey information to locate potential 

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sensitive species habitats. In addition, the RFO staff has information that identifies potential habitats by 

soil type and known populations of these species. 

4.9.3.2 Alternative A: 100-Percent Vertical Drilling 

Threatened, Endangered, Proposed, or Candidate Wildlife Species 

Under Alternative A, the types of impacts to special status species and their habitats would be similar to 

those described for the Proposed Action. For this alternative, the scope and intensity of the impacts would 

be more widespread because of the increased surface disturbance associated with construction of more 

well pads, roads, and pipelines required for 100-percent vertical drilling. The total number of well pads 

and access roads would be 8,950, compared to the estimated 6,126 well pads estimated for the Proposed 

Action. Estimated surface disturbance for this alternative would be 31 percent greater (14,496 acres) than 

the Proposed Action. Combined with previous surface disturbance, more than 11 percent of the project 

area would be disturbed at one time or another. After successful reclamation, the project-related acreage 

that would remain in a non-vegetated state would be 28 percent greater (5,272 acres) than the Proposed 

Action. Shrub-dominated habitat would not recover during the life of the project. Habitat loss and 

fragmentation would be comparably more extensive than under the Proposed Action. Impacts to species 

already likely to exceed significance criteria such as sage-grouse in non-core areas would be increased 

and are expected to exceed Criteria 2 and 3. Additionally, in the checkerboard portion of the project area, 

the RMP limitations do not apply to private and state lands, so it is possible that impacts to species with 

large indirect impact zones, such as nesting/foraging ferruginous hawks, could reduce the effectiveness of 

the mitigation on BLM land, possibly leading to exceeding impact significance Criterion 4. Although this 

increase of surface disturbance would increase the impact to shrub dependent bird species such as 

Brewer’s sparrow, loggerhead shrike, sage sparrow, and sage thrasher, it should not reach the level of 

significance under Criterion 4. 

The BLM will seek to apply conservation measures for greater sage-grouse in state-designated core 

population areas consistent with IM WY-2012-019 (BLM 2012c), pending the amendment of the Rawlins 

RMP. In non-core areas, leks would be protected by the application of the 0.25-mile lek NSO as well as 

the Rawlins RMP requirement to avoid identified nesting and early brood-rearing habitat, regardless of 

distance from a lek, from March 1 to July 15. Timing Limitations would provide additional seasonal 

protection to wintering sage-grouse in non-core areas. It is expected that greater than three wells or 60 

acres of disturbance per square mile could occur within the 2-mile radius of some non-core leks but not 

all; this would be considered an “Extreme Impact” relative to those individual leks (WGFD 2010a). 

As discussed in the Proposed Action, ferruginous hawk nests located near private or state surface in the 

checkerboard would not benefit from the entire 1-mile seasonal buffer zone. It is difficult to determine if 

this would exceed Criterion 4 in this case because other factors such as topography could decrease the 

size of the needed buffer around nests, but the impacts are not expected to exceed the criterion. 

Other sensitive species including mountain plover and white-tailed prairie dog would be provided 

protections for nest and habitat avoidance, as appropriate, on BLM-managed lands but not on private and 

state-managed lands. Given the increased acreage anticipated to be disturbed under this Alternative it is 

expected that Criterion 4 may be exceeded for these species. 

Although the increase of surface disturbance anticipated under this alternative would increase the impact 

to shrub-dependent bird species such as Brewer’s sparrow, loggerhead shrike, sage sparrow, and vespers 

sparrow, it is not likely to reach the level of significance under Criterion 4. 

Threatened and Endangered Fish Species 

Impacts to Threatened and Endangered fish species would be the same as for the Proposed Action. 

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Sensitive Fish Species 

The types of impacts to sensitive fish species would be the same as for the Proposed Action, but because 

of the larger surface area affected, the magnitude of the impacts would be proportionally greater. 

Special Status Plants 

Although the amount of surface disturbance would be greatly increased under Alternative A, the measures 

to avoid and protect special status plants that would be implemented make it unlikely that special status 

plants would be more affected by implementation of Alternative A than by the Proposed Action. 

4.9.3.3 Alternative B: Enhanced Resource Protection 

Threatened, Endangered, Proposed, or Candidate Wildlife Species 

The ERP alternative was developedin part to prevent significant impacts to wildlife resources of concern 

by implementing additional protections and mitigations, when necessary, beyond those normally applied 

(e.g. BMPs, COAs, Wildlife Monitoring and Protection Plan). The ERP alternative also recognizes that 

development may be more intensive than currently expected and may result in impacts to wildlife habitats 

and populations faster than anticipated. This alternative would combine prescriptive and adaptive 

management approaches, which includes assessing the specific issue, designing and implementing a 

response, monitoring and evaluating results, and adjusting the management response when needed on a 

case-by-case basis. The enhanced resource protections would go into effect immediately and be applied to 

all future APDs and other project-related activities. Should surface disturbance or population thresholds 

be reached, additional protection measures would also be implemented, specific to each affected species. 

See Section 2.23 for a detailed description of this alternative. 

The additional restrictions under this alternative are likely to encourage the use of directional drilling and 

enhanced reclamation practices. For this reason, the scope and intensity of impacts on special status 

species and their habitat would be less. Maximum initial surface disturbance for this alternative is 

estimated to decrease by 1,684 acres to 45,516 acres, a 3.6 percent reduction from the Proposed Action. 

Long-term disturbance would decrease by 611 acres, to 18,249 acres. 

Because more wells would likely be drilled directionally from multi-well pads under this alternative, 

fewer well pads overall would be constructed—an estimated 5,798 compared to the estimated 6,126 well 

locations of the Proposed Action, a reduction of 5.4 percent. Therefore, fewer access roads would be 

developed and habitat fragmentation would be less extensive than for the Proposed Action. 

The special status species/habitat that would receive enhanced protections under this alternative include 

greater sage-grouse leks, nesting/brood-rearing habitat, and winter concentration areas, and ferruginous 

hawk nest habitat. Enhanced protections afforded these species and their habitats would benefit numerous 

other species. The following additional mitigation measures, along with many others more specific to 

special status species, are included in this alternative: 

 Minimize human presence at well sites after they have been put into production by installing remote 

monitoring devices on project facilities and gating roads; 

 Utilize noise-reduction techniques; 

 Timely reclaim well pads, pipelines, and rights-of-way to reduce displacement of wildlife from the 

well field; 

 Provide training programs for field workers to raise awareness of activities that cause stress to 

wildlife, times of day when collisions are most likely, and other programs as necessary; 

 Install devices to preclude raptor-perching near prairie-dog towns and pygmy rabbit burrows; and 

 Bury new power lines near sage-grouse leks. 

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Greater sage-grouse. The enhanced protections for greater sage-grouse would decrease the degree of 

impact, especially in non-core areas, as compared to the Proposed Action. These enhanced protections 

would be in addition to protections normally applied (e.g. BMPs, COAs, Wildlife Monitoring and 

Protection Plan) and protections described in IM WY-2012-019 for sage-grouse core areas. Applications 

for Permit to Drill (APDs) within greater sage-grouse lek, nesting/brood-rearing habitat, and winter 

concentration areas would be submitted as part of an overall development plan for an entire lease or 

several leases. The plan is described previously in the general requirements portion of the alternative. 

In addition, the following requirements would be implemented throughout sage-grouse habitat: 

 Burying new power lines and using low-profile facilities within 1 mile of an occupied lek or in 

winter concentration areas; 

 Use of noise-reduction technology so that noise would not exceed 49 decibels measured at 30 feet 

from the source at all drilling, production and compressor sites; and 

 No more than one oil and gas or mining location per 640 acres and no more than 5 percent habitat 

disturbance (related to all programs or applicable sources of disturbance). 

Additionally, surface-disturbance and population thresholds have been developed as part of this 

alternative to maintain sage-grouse habitat and populations in the face of increasing development 

pressure. 

Surface-disturbance thresholds would reduce the risk of impacts of habitat removal and modification in 

sage-grouse habitats. The surface-disturbance thresholds seek to reduce the amount of habitat disturbed 

and to mitigate disturbance with reclamation. If surface disturbance for natural gas roads, pipelines, well 

pads or other facilities has exceeded 5 percent or one oil and gas or mining location per 640 acres within 

core areas, the BLM would: 

 Require remote well-monitoring at all well pads; 

 Evaluate reclamation success in the section and request from the Operator a revised reclamation 

plan to address any failed reclamation. The calculated percentage disturbance would be adjusted 

downward for successful interim reclamation. 

 Conduct an assessment of the disturbance and determine if enhancement of sage-grouse habitat is 

needed at that time. If so, begin implementation. 

If surface disturbance were to reach 10 percent or 2 oil and gas or mining locations per 640 acres of noncore sage-grouse lek, nesting/early brood-rearing habitat, or winter concentration areas in a lease, habitat 

improvement projects would be required. Projects could include, but would not be limited to: 

 Vegetation treatments such as fertilization, seeding, prescribed burning, cutting/chopping for 

regeneration, planting shrubs, and establishment of food plots; and
 

 Water developments.
 

Population-level thresholds are intended to maintain sage-grouse population levels within the project area. 

If WGFD were to express formal written concern that the population of sage-grouse is declining at an 

accelerated rate, all Operators on public lands within sage-grouse lek, nesting/early brood-rearing habitat 

or winter concentration areas would implement a mitigation package identified by BLM that would 

include, but would not be limited to: 

	 Evaluation of reclamation success in the lease or right-of-way and a request to the Operator to 

provide a revised reclamation plan to address any failed reclamation. 

	 Vegetation treatments such as fertilization, seeding, prescribed burning, cutting/chopping for 

regeneration, planting shrubs, and establishment of food plots (the BLM may also coordinate habitat 

improvement projects among multiple Operators); and 

	 Timing and Distance Restrictions (Non-core areas to conform with core areas): 

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o	 When the threshold is reached, surface-disturbing activity or surface occupancy would be 

prohibited or restricted on or within a 0.6 mile of the perimeter of occupied sage-grouse leks. In 

addition, disruptive activities within 0.6 mile of the perimeter of occupied sage-grouse leks are 

restricted from 6:00 pm to 9:00 am from March 1 – May 15. 

o	 Avoid surface-disturbing and disruptive activities in suitable greater sage-grouse nesting and 

early brood rearing habitat within 2.5 miles of the perimeter of an occupied lek from March 15 

– June 30. 

o	 Prohibition of surface-disturbing and disruptive activities within 0.5 mile of non-core sagegrouse winter concentration areas from November 15 – March 14. 

	 Density Restrictions: 

o	 Core area APDs would be limited to the density disturbance calculation tool thresholds (see 

density restrictions in IM 2012-019). When thresholds are exceeded, the BLM would work to 

colocate or minimize disturbance for valid and existing rights. 

o	 When the population threshold is reached in non-core areas, strive to maintain <3 pads per 

square mile within 2 miles of the perimeter of occupied sage-grouse leks 

If the population status of the species changes in the future, additional data would be collected and 

additional protection measures would be developed. 

Standard density restrictions in defined core population areas would limit the density of disruptions on the 

landscape to 1 well pad per 640 acres or the cumulative area of disturbance to less than 5 percent of the 

suitable sagebrush habitat within the same 640 acres (IM WY-2012-019). In non-core areas the Rawlins 

RMP provides timing stipulation protection to identified nesting and early brood-rearing habitat 

regardless of the distance from a lek. With these protection measures, habitat in sage-grouse lek, 

nesting/early brood-rearing habitat, or winter concentration areas should be maintained. The risk of a 

significant population decrease resulting from gas development is expected to decrease under this 

alternative. Impacts to sage-grouse in both core and non-core areas should not reach the level of 

significance under this alternative provided the Core Population Area mitigation measures found in the 

IM, the RMP, and the State Executive Order are applied and the 5 percent surface disturbance trigger is 

effective at predicting habitat impact issues in advance of Criterion 4 being exceeded. 

Ferruginous Hawk Nesting Habitat. Under this alternative, the basic RMP requirements and standard 

site-specific requirements would apply. Currently, there are 84 known ferruginous hawk territories within 

the project area. No additional protections would apply to ferruginous hawk nesting habitat unless one of 

the two following thresholds were reached—a surface disturbance threshold and a population threshold: 

In the event that surface disturbance within 1 mile of a ferruginous hawk nest exceeds 10 percent, 

Operators in all leases within the 1 mile nest radius of would be required to participate in a 

development/mitigation plan before additional APDs would be issued. 

If WGFD were to express formal written concern about the ferruginous hawk population, the following 

mitigation measures would be implemented immediately: 

	 All existing development features and facilities (pads, pipelines, roads, holding yards, compressor 

stations, and other associated infrastructure) within the nesting territories would be inspected to 

determine reclamation success. If reclamation has been unsuccessful, measures would be taken to 

improve the reclamation of the facilities. 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—SPECIAL STATUS SPECIES 

	 Ten man-made19 nests would be built outside of existing monitoring territories on natural substrates, 

and farther than 1,200 feet from existing disturbances, prior to January 10th of the year following 

receipt of WGFD’s letter of concern. 

o	 The farther the nest is constructed from existing disturbances the better. 

o	 These nests would be incorporated into the annual monitoring efforts. 

o	 Controlled Surface Use and Timing Limitation stipulations would be applied to any nests that 

become occupied by raptors. 

	 Two artificial nesting structures 20 would be placed outside of existing monitoring territories, and 

farther than 1,200 feet from existing disturbances, prior to January 10th of the year following receipt 

of WGFD’s letter of concern. 

o	 Priority for placement of these nests would be determined based on information regarding 

extant nests located on man-made infrastructure, or where there is known repeated attempts at 

nesting on man-made infrastructure. 

o	 These nests would be incorporated into the annual monitoring efforts. 

o	 Controlled Surface Use and Timing Limitation stipulations would be applied to any nests that 

become occupied by raptors. 

If the species population continues to decline, additional data would be collected and additional protection 

measures would be developed. 

With these protection measures, nesting habitat and fledgling production should be maintained, even in 

the checkerboard area. The risk of population decrease resulting from gas development is expected to 

decrease from the Proposed Action and would not be expected to exceed the impact significance criteria. 

Under the Enhanced Resource Protection Alternative, other special status species discussed in the 

Proposed Action (e.g. pygmy rabbit, mountain plover, white-tailed prairie dog, swift fox, long-billed 

curlew, Great Basin spadefoot, northern leopard frog, etc.) would have no additional specific species 

protections beyond those required by the RMP (timing and surface stipulations), BMPs (Appendix C) 

and the Wildlife Monitoring and Protection Plan. However, by implementing the ERP alternative, many 

of these species would benefit from the additional protections. For example, riparian species and northern 

leopard frogs would benefit from the enhanced protections of the Muddy Creek corridor/watershed, Chain 

Lakes wetlands, and playas. 

Threatened and Endangered Fish Species 

Impacts to Threatened and Endangered fish species would be the same as for the Proposed Action. 

Sensitive Fish Species 

The Enhanced Resource Alternative Protections for the Muddy Creek and Bitter Creek 

Corridors/Watersheds described in Section 2.2.3.4 could significantly reduce project impacts to sensitive 

fish species. The sources of these reductions would include the following protections: 

	 For protection of amphibians and their habitats, avoidance of surface-disturbing and disruptive 

activities within 0.25 mile of Red Wash, springs, wells, and wetlands would be required. The 

required avoidance distance would be further increased on perennial streams to 0.5 mile. Exceptions 

would only be granted by the BLM based on environmental analysis and site-specific engineering 

and mitigation plans. Only actions within areas that could not be avoided and that would provide 

19 Man-made nests are nests that are built in appropriate habitat and are intended to attract ferruginous hawks. 

20 Artificial nesting structures are built to attract hawks that would build their own nest on the structure. 

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protection for the resource identified would be approved. In-channel activities would be restricted to 

the low-flow period. 

	 Current monitoring on upper Muddy Creek would be extended to lower Muddy Creek in the CD-C 

project area. This requirement would bring lower Muddy Creek into conformance with the 

monitoring being done for upper Muddy Creek and other drainages within the Atlantic Rim project 

area. If results of the monitoring program showed impacts to sensitive fish habitat, the BLM and an 

interagency CD-C consultation group would determine whether habitat-improvement projects 

should be implemented. The projects could include, but would not be limited to, increasing the 

number of drainage features along roads, increasing in-stream cover for fish, and other measures as 

necessary. 

	 A monitoring plan for the Bitter Creek watershed will be designed. 

The following requirements related to selenium and salinity for well locations and operations would also 

be implemented: 

	 No surface discharge of produced waters within the Muddy Creek and Bitter Creek watersheds. 

	 Line all reserve pits in the Muddy Creek and Bitter Creek watersheds. 

These protections, however, would only apply to BLM land (an estimated 48 percent of the total area). An 

unintentional consequence of these protections could be to increase drilling activities on private land and 

state land. Such development on private and state land along Muddy Creek could completely negate the 

enhanced resource protections on BLM land along Muddy Creek. To preclude this possibility, the 

Operators and the state should make a commitment to apply these same enhanced resource protections to 

private and state land along Muddy Creek. Without this commitment, it is likely that the impacts to 

sensitive fish species for this alternative would be the same as for the Proposed Action alternative. 

Sensitive Plant Species 

Special-status plants would receive no added protection under Alternative B. The measures aimed at 

avoiding and protecting special status plants that would be implemented under the Proposed Action and 

all alternatives would ensure that special status plants would not be affected by implementation of 

Alternative B any more than they would under the Proposed Action. 

4.9.3.4 Alternative C: Surface Disturbance Cap – High and Low Density Development Areas 

Threatened, Endangered, Proposed, or Candidate Wildlife Species 

This alternative differentiates between existing high-density development areas—those areas that have 

seen the greatest natural-gas development to date—and low-density development areas (Map 2-1), 

placing a higher cap on disturbance in areas that have already undergone considerable development. 

Within the high-density development areas, a 60-acre cap would be placed on the amount of unreclaimed 

surface disturbance allowed at any one time in a section of public land. For the remainder of the project 

area—the low-density development areas—the cap would be 30 acres per section. All prior surface 

disturbance committed to long-term use for roads or on-pad production facilities and all disturbance that 

had not been successfully reclaimed would count against the cap. Acreage that had successfully 

undergone interim reclamation would not count against the cap. In general, adverse impacts in both areas 

should be reduced compared to the Proposed Action. 

Under Alternative C, the types of impacts to special status wildlife species and their habitats would be 

similar to those described for the Proposed Action. The cap, however, would place a limit on the amount 

of unreclaimed surface disturbance at any one time in a section of public land. This requirement should 

encourage the use of directional drilling and enhanced reclamation practices. For this reason, the scope 

and intensity of impacts on special status species and their habitat would be less. Maximum surface 

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disturbance for this alternative is estimated to decrease by 4,245 acres in the short term to 42,955 acres, a 

9 percent reduction from the Proposed Action. Long-term disturbance would decrease by 1,543 acres, to 

17,318 acres. 

Because more wells would be drilled from directional well pads under this alternative, fewer well pads 

overall would be developed—an estimated 5,299 compared to the estimated 6,126 well locations of the 

Proposed Action, a reduction of 13.5 percent. Therefore, fewer access roads would be developed, fewer 

pipelines would be installed, fewer haul-truck miles would be logged, and habitat fragmentation would be 

less extensive than for the Proposed Action. 

Greater sage-grouse should benefit from fewer wells and disturbance. In the core areas, restrictions found 

in IM WY-2012-019 and the Greater Sage-grouse Core Area Protection program (SGEO) (SWED 2011) 

would apply in many instances, so impacts may not exceed the impact significance criteria. In non-core 

areas, application of RMP and IM timing stipulations in potential nesting and brood-rearing habitat as 

well as the BLM standard COAs, BMPs, and mitigation would reduce the potential impact to sage-grouse 

although some impact to those populations would still be anticipated over the long term. The protections 

found in the SGEO would apply in non-core areas on non-federal lands. Impacts to sage-grouse in both 

core and non-core areas should not reach the level of significance under this alternative provided the Core 

Population Area mitigation measures found in the IM, RMP, and SGEO are applied. As discussed in the 

Proposed Action alternative, ferruginous hawk nests located near private or state surface in the 

checkerboard would not benefit from the entire 1-mile seasonal buffer zone. It is difficult to determine if 

this would exceed Criterion 4 in this case because other factors such as topography could decrease the 

size of the needed buffer around nests. Impacts to white-tailed prairie dog and mountain plover are not 

expected to exceed Criterion 4 as the protection measures found in the RMP would be applied. 

Threatened and Endangered Fish Species 

Impacts to Threatened and Endangered fish species would be the same as for the Proposed Action. 

Sensitive Fish Species 

Within the project area, about 59 percent of the Muddy Creek watershed is located in the high-density 

area and about 41 percent is in the low-density area (Map 2-1). Because surface disturbance would be 

capped at 30 acres per section in the low-density area and at 60 acres per section in the high-density area, 

impacts to fish in Muddy Creek as a result of surface disturbance should be less under this alternative 

compared with the Proposed Action. Without the added types of protections for Muddy Creek discussed 

in Section 4.8.3.3 for Alternative B, however, the impacts to sensitive fish species could be similar to 

those for the Proposed Action. 

Sensitive Plant Species 

The measures aimed at avoiding and protecting special status plants that would be implemented under the 

Proposed Action and all alternatives would ensure that special status plants would be as little affected by 

implementation of Alternative C as by the Proposed Action. To the extent that surface disturbance 

decreases and the number of disturbance sites is reduced, the likelihood of adverse impacts is diminished 

further. 

4.9.3.5 Alternative D: Directional Drilling 

Threatened, Endangered, Proposed, or Candidate Wildlife Species 

Under Alternative D, the types of impacts to special status species and their habitats would be similar to 

those described for the Proposed Action. This alternative requires that all future natural gas wells on 

federal mineral estate and surface be drilled from multi-well pads. In sections that have already undergone 

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development, the enlargement of one existing well pad would be permitted as the multi-well pad for all 

future drilling in that section. No new roads or pipeline routes would be permitted in these leases. In 

sections that have not been developed, one new well pad would be permitted for all future development. 

One road and pipeline corridor on the lease would be permitted. The objective of this alternative is to 

minimize surface disturbance and to reduce habitat loss and wildlife disturbance. It would also reduce 

fragmentation of habitat. Total surface disturbance for this alternative would decrease by 10,751 acres to 

36,449, a reduction of about 23 percent from the Proposed Action. Long-term disturbance is estimated to 

decrease by 3,908 acres to 14,952 acres, a reduction of about 21 percent. 

Most wells would be drilled from directional well pads under this alternative and fewer well pads overall 

would be developed—an estimated 4,032 compared to the estimated 6,126 for the Proposed Action, for a 

reduction of about 34 percent. Therefore, fewer access roads would be constructed and fewer pipelines 

installed, and habitat fragmentation would be less extensive than for the Proposed Action. However, noise 

from drilling and completion activities occurring at long-duration multi-well pads could represent a 

localized negative impact to a sub-set of sensitive receptors (i.e. nesting raptors, lekking or brooding sagegrouse) due to the increased period of time required for drilling and well completion activity at a single 

location. Reduced surface disturbance and habitat fragmentation resulting from multi-well pads comes 

with an increase in decibel level and frequency of that noise, as well as the extended period of time over 

which large haul-truck activity would occur. 

Because this alternative reduces the number of active well locations to be drilled along with associated 

roads and pipelines, impacts to most species would be reduced under this alternative compared to the 

Proposed Action. Impacts to the habitats of those species that depend on shrubs (sage-grouse and the 

shrub-dependent songbirds) would be significantly less than the Proposed Action due to the decrease in 

impacted habitat. 

In addition to the reduced surface disturbance and fragmentation resulting from Alternative D, 

implementation of the BLM IM and State Executive Order sage-grouse protections would reduce impacts 

to greater sage-grouse in core areas. Mitigations and restrictions applied for protection of sage-grouse in 

non-core areas (BLM 2012c and WSEO 2010) would apply on all remaining sage-grouse habitat in the 

project area, regardless of ownership, as appropriate. 

As discussed in the Proposed Action, ferruginous hawk nests located near private or state surface in the 

checkerboard would not benefit from the entire 1-mile seasonal buffer zone; however, the reduced 

number of well locations on BLM-administered lands should further decrease risks to the species. It is not 

expected that Criterion 4 would be exceeded as other factors such as topography could decrease the size 

of the needed buffer around nests. 

Threatened and Endangered Fish Species 

Impacts to Threatened and Endangered fish species would be the same as for the Proposed Action. 

Sensitive Fish Species 

Total surface disturbance for this alternative would be about 23 percent lower than for the Proposed 

Action; therefore, impacts to sensitive fish species should be proportionally less. 

Sensitive Plant Species 

The measures aimed at avoiding and protecting special status plants that would be implemented under the 

Proposed Action and all alternatives would ensure that special status plants would be as little affected by 

implementation of Alternative D as by the Proposed Action. To the extent that surface disturbance 

decreases and the number of disturbance sites are reduced, the likelihood of adverse impact would be 

diminished even further. 

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4.9.3.6 Alternative E: No Action 

Under the No Action Alternative it is assumed that no further natural gas development would occur 

within the CD-C project area. There would consequently be no new surface disturbance and no new 

impacts on special status species or their habitat. These species would continue to be affected by earlier 

habitat alterations, by human activity in the vicinity of natural gas production facilities, by traffic in the 

project area, and by diminished palatability of browse and forage caused by dust. 

The Rawlins RMP (BLM 2008b) prescribes the following management objectives associated with 

wildlife and fisheries resources (including Special Status Species): 

	 Maintain, restore, or enhance wildlife habitat in coordination and consultation with other local, 

state, and federal agencies and consistent with other agency plans, policies, and agreements. A full 

range of mitigation options will be considered when developing mitigation for project-level 

activities for wildlife and Special Status Species habitats. 

	 Maintain, restore, or enhance T&E species habitat, in coordination and consultation with the 

USFWS and other local, state, and federal agencies and consistent with other agency plans, policies, 

and agreements. 

	 Maintain, restore, or enhance designated BLM State Sensitive Species habitat to prevent listing 

under the ESA, in coordination and consultation with other local, state, and federal agencies and 

consistent with other agency plans, policies, and agreements. 

	 Maintain, restore, or enhance habitat function in crucial winter range. 

The RMP also defines the following impact significance criteria that are used in this document to assess 

the impacts associated with the Proposed Action and alternatives (BLM 2008b). Impacts to special status 

wildlife and fish species would be considered significant if any of the following were to occur: 

1.	 Substantial loss of the biological integrity and habitat function of terrestrial and aquatic ecosystems 

that would make a species eligible for listing under the ESA. 

2.	 Decreased viability or increased mortality of Threatened, Endangered, Proposed, and/or Candidate 

species, or adverse alteration of their critical habitats. 

3.	 Substantial loss of habitat function or disruption of life-history requirements of special status 

species that would preclude improvement of their status. Habitat function means the arrangement of 

habitat features and the capability of those features to sustain species, populations, and diversity of 

wildlife over time (WGFD 2010a). 

4.	 Actions that preclude attainment of conservation goals, as stated in conservation plans and 

strategies for special status species. (Not in the RMP but added by RFO staff to this list.) 

Impacts to special status plant species would be considered significant if any of the following were to 

occur: 

1.	 Any action or event that would remove a community’s unique attributes or ability to support other 

resource values within the planning period, or if corrective actions were beyond the scope of the 

RMP. 

2.	 The viability of protected plant species is jeopardized, with little likelihood of reestablishment after 

disturbance, or actions result in the need to list a species under ESA. 

3.	 Actions that have the potential to remove sensitive plant species or substantially alter the habitat’s 

ability to support the species. 

4.	 Actions that preclude attainment of conservation goals, as stated in conservation plans and strategies 

for special status species. (Not in the RMP but added by RFO staff to this list.) 

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4.9.4 Impact Summary 

The project, as proposed, would disturb and alter approximately 47,200 acres of wildlife habitat over the 

next 15 years, in addition to the 60,176 acres already disturbed by natural-gas and other development. 

Reclamation of disturbed areas should recover grass-dominated habitats in one to several years, 

depending on precipitation and effectiveness of reclamation efforts. Shrub habitats would not reach predisturbance levels during the life of the project. Therefore, shrub-dependent special status species would 

be impacted most by habitat loss. 

In addition to the physical removal of habitat, disturbance during construction and production can 

displace or preclude wildlife use during all seasons. Timing restrictions for the critical times of year have 

been developed for the most sensitive species and are generally implemented during the development 

phase, but no restrictions would be in place during the production phase. Other impacts from natural-gas 

development include habitat fragmentation, reduced availability and palatability of forage due to dust, and 

mortality from collision between vehicles and wildlife. The measures aimed at avoiding and protecting 

special status plants that would be implemented under the Proposed Action and all alternatives would 

ensure that potential impacts to special status plants would be minimized or eliminated. 

Proposed Action. It is expected that for the Proposed Action, Criteria 2 and 3 (Decreased viability or 

increased mortality of Threatened, Endangered, Proposed, and/or Candidate species, or adverse 

alteration of their critical habitats. and Substantial loss of habitat function or disruption of life-history 

requirements of special status species that would preclude improvement of their status.) could be 

exceeded for sage-grouse outside the core area. Additionally, ferruginous hawk nests located near private 

or state surface in the checkerboard would not benefit from the entire 1-mile seasonal buffer zone but it is 

not expected that Criterion 4 would be exceeded as other factors, such as topography, could decrease the 

size of the needed buffer around nests. Other special status species should be protected sufficiently by the 

COAs, RMP requirements, and BMPs to avoid exceeding the significance level. 

The primary source of potential risks to fish species from land disturbance from project activities would 

be increases in suspended sediments and sedimentation. The intensity of these impacts may decrease with 

the completion of the construction phase and with the onset of reclamation efforts on disturbed areas. 

None of the Threatened and Endangered fish species found downstream of the project area within the 

Colorado River system are known to occur in the project area; therefore, there would be no direct impacts 

to these species. Implementation of all mitigation measures for water and soils would help reduce other 

potential impacts. Accidental releases of produced waters or other materials also could occur. However, 

these materials would become highly diluted before they would reach any downstream waters where these 

species occur; consequently, the potential risks from such occurrences would be negligible. 

With the implementation of the Proposed Action, direct loss of habitat for sensitive fish species would 

result from sedimentation associated with the construction of well sites and related access roads and 

pipelines. Accidental releases of produced waters or other materials could occur. Alteration of sensitive 

fish habitat suitability from sedimentation would result in significant impacts to sensitive fishes (Criteria 

3 and 4). 

Alternative A: 100-percent Vertical Drilling would affect an additional 14,496 acres of wildlife habitat 

(a 30.7-percent increase). The impacts described above would be greatly intensified under this alternative 

and Criteria 2 and 3 would likely be exceeded for sage-grouse outside the core area. Criterion 4 (Actions 

that preclude attainment of conservation goals, as stated in conservation plans and strategies for special 

status species.) would not be exceeded for ferruginous hawks. 

Impacts to threatened and endangered fish species would be the same as for the Proposed Action. Overall, 

the types of impacts to sensitive fish species would be similar to those described for the Proposed Action; 

however, the level of impacts would be greater due to increased surface disturbance. Accidental releases 

of produced waters or other materials also could occur with significant consequences. Alteration of fish 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—SPECIAL STATUS SPECIES 

habitat suitability from sedimentation would result in significant impacts to sensitive fish species (Criteria 

3 and 4). 

Alternative B: Enhanced Resource Protection was designed to reduce impacts of development on those 

species or habitats that are most vulnerable to an infill oil and gas project. There would be a slight 

reduction (1,684 acres, about 3.5 percent) in the amount of wildlife habitat disturbed under this alternative 

compared to the Proposed Action, but because of the additional mitigation requirements, impacts to sagegrouse outside core areas and ferruginous hawks should be reduced to a level below significance. Other 

special status species (white tailed prairie dogs, Wyoming pocket gopher, pygmy rabbits, mountain 

plovers and neotropical birds) would also benefit from this alternative. The additional protection of the 

Muddy Creek watershed, riparian areas, and playas would also benefit a number of special status species. 

Impacts to Threatened and Endangered fish species would be the same as for the Proposed Action. The 

Enhanced Resource Protections for the Muddy Creek Corridor/Watershed described in Section 4.2.3.9 

could significantly reduce project impacts to sensitive fish species if they were applied to both BLM and 

private land within the project area. Without the application of these protections to private land, however, 

the benefits of these enhanced resource protections could be negated by increased drilling activities on 

private land. Accidental releases of produced waters or other materials also could occur. Without this 

commitment, alteration of fish habitat suitability from sedimentation could result in significant impacts to 

sensitive fish species (Criteria 3 and 4). With such a commitment, the project area and other human 

activities within the Muddy Creek and Great Basin watersheds should not have significant cumulative 

impacts on the status of their populations within Wyoming. 

Alternative C: Surface Disturbance Cap – High and Low Density Development Areas seeks to 

reduce habitat disturbance and reward successful reclamation. It is expected to impact 4,245 fewer acres 

than the Proposed Action. It should reduce the impacts to all species below that of the Proposed 

Alternative, but impacts would still be expected to exceed the significance level for sage-grouse in noncore areas. While fewer wells should help nesting ferruginous hawks, it is still possible the significance 

level would be reached in the checkerboard area. 

Impacts to Threatened and Endangered fish species would be the same as for the Proposed Action. 

Because only a small proportion of Muddy Creek is on BLM land in high-density development areas, 

impacts to sensitive fish species would be less than under the Proposed Action. Alteration of fish habitat 

suitability from sedimentation, however, still would result in significant impacts to sensitive fish species 

(Criteria 3 and 4). Accidental releases of produced waters or other materials also could occur with 

significant consequences. 

Alternative D: Directional Drilling would be expected to reduce surface-disturbance acreage by 

approximately 23 percent, when compared to the Proposed Action; anticipated impacts to special status 

species in the project area would be below the point of significance. Impacts to threatened and 

endangered fish species would be the same as for the Proposed Action. Because the amount of land 

disturbed under this alternative would be less than for the Proposed Action, impacts to fish should be 

proportionally less. Accidental releases of produced water or other materials also could occur with 

significant consequences. Alteration of fish habitat suitability from sedimentation would result in 

significant impacts to sensitive fish species (Criteria 3 and 4). 

Alternative E: No Action is assumed to result in no new surface disturbance and no new impacts on 

special status species or their habitat because no further natural gas development would occur within the 

CD-C project area on federal, state, or fee mineral estate. 

4.9.5 Unavoidable Adverse Impacts and Additional Mitigation Measures 

Criterion 1—Substantial loss of the biological integrity and habitat function that would make a species 

eligible for listing under the ESA— is not expected to be exceeded under the Proposed Action or any of 

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the alternatives for any species. Criterion 2— Decreased viability or increased mortality of Threatened, 

Endangered, Proposed, and/or Candidate species—would be exceeded for greater sage-grouse in noncore areas under the Proposed Action and all action alternatives except Alternative B. Criterion 2— 

Substantial loss of habitat function or disruption of life-history requirements—would be exceeded for 

greater sage-grouse in non-core areas under The Proposed Action and all action alternatives except 

Alternative B. It would also be exceeded for sensitive fish species. Criterion 4—Actions that preclude 

attainment of conservation goals—may be exceeded for ferruginous hawks under Alternative A and 

would be exceeded for sensitive fish species under the Proposed Action and all action alternatives. The 

measures aimed at avoiding and protecting special status plants under the Proposed Action and all 

alternatives would insure that potential impacts to special status plants would not be exceeded under the 

Proposed Action or any action alternatives. 

The exceedances of Criteria 2 and 3 for greater sage-grouse in non-core areas could be avoided by 

application of the protections and mitigations for greater sage-grouse found in Alternative B, including: 

 Burying new power lines and using low-profile facilities within 1 mile of an occupied lek or in 

winter concentration areas; 

 Use of noise-reduction technology so that noise would not exceed 49 dBa measured at 30 feet from 

the source at all drilling, production and compressor sites; and 

 Enhance timing, distance, and density restrictions within high value habitats. 

The exceedances of Criteria 3 and 4 for sensitive fish species under the Proposed Action and all action 

alternatives could be avoided by application of the increased set-back distances found in the Muddy 

Creek watershed in Alternative B to private and state lands as well as public lands. Those increased 

distances are from 500 feet to 0.25 mile of Red Wash, springs, wells, and wetlands and to 0.5 mile from 

perennial streams. 

Additional mitigation measures whose general application would benefit numerous special status species 

include the following: 

 Minimizing human presence at well sites after they have been put into production by remote 

monitoring of project facilities and gating of roads;
 

 Development of travel management plans; 

 Utilization of noise-reduction techniques; 

 Training programs for field workers to raise their awareness of activities that cause stress to 

wildlife, times of day when collisions are most likely; and 

 Installation of devices to preclude raptor-perching near prairie-dog towns and pygmy rabbit 

burrows. 

These additional mitigation measures, along with others more specific to special status species, are 

included in Alternative B, Enhanced Resource Protection. 

4.10 WILD HORSES 

4.10.1 Introduction 

Surface-disturbing activities associated with the construction of well pads, reserve pits, and roads could 

adversely affect wild horses. Land-clearing and grading activities necessary for construction remove 

vegetation, resulting in loss of forage, and create disturbance through increased human activity. Assuming 

successful reclamation, BLM standards for reclamation of disturbed sites such as linear road and pipeline 

rights-of-way and well pad sites would be adequate to mitigate any potential adverse effect on wild horses 

because of forage loss. 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—WILD HORSES
 

Prevention and containment of invasive plant species establishment and spread would have a positive 

impact to wild horses, wildlife, and livestock by reducing competition with native plants, consequently 

maximizing forage production. 

4.10.2 Management Objectives and Impact Significance Criteria 

The Rawlins RMP (BLM 2008a) lists the following management objectives for wild horses: 

1.	 Maintain wild horse populations within the appropriate management levels (AML) of the HMA. 

2.	 Manage wild horses to meet the Wyoming Standards for Healthy Rangelands. 

3.	 Identify existing genotypes and phenotypes through recognized means of genetic evaluation and 

maintain genetic integrity. 

4.	 Maintain habitat for existing AMLs. 

5.	 Conduct all activities in compliance with relevant court orders and agreements, including the 

Consent Decree (August 2003). 

Impacts to the wild horse resource would be considered significant if any of the following were to occur: 

	 Resource management actions resulting in greater than a 10-percent permanent reduction in animal 

unit months (AUMs) available for livestock grazing within a given allotment. In the case of the Lost 

Creek HMA, this would apply only to the Cyclone Rim allotment as it is the only grazing allotment 

within the HMA boundary in the CD-C project area (Map 3.10-1). The Adobe Town HMA 

occupies a very small portion of the project area (5,826 acres), primarily located in the Continental, 

Red Creek, South Flat Top and Willow Creek allotments. 

 Available forage, water, or other habitat components are not sufficient to achieve or maintain the 

appropriate management level (AML) in a given HMA. 

 Viability of wild horse populations cannot be maintained. 

 The wild, free-roaming character of a wild horse herd in an HMA is lost. 

 Wyoming BLM Standards for Healthy Rangelands are not met. 

 Vegetation significance criteria are not met (Section 4.6.2). 

 Non-compliance with any provision of the Free-Roaming Wild Horse and Burro Act of 1971.
 

4.10.3 Direct and Indirect Impacts 

The wild horse resource would be directly impacted by the intensity and timing of development within the 

affected herd management area (HMA) and indirectly by any quantitative or qualitative changes to the 

vegetation resource. The primary impact to wild horses would be initial loss of available forage as a result 

of construction and production-related disturbances. Available forage would be reduced during drilling 

and field-development and reclaimed as soon as feasible under direction of the current BLM reclamation 

guidelines and recommendations (Section 4.6.3.1). A long-term loss of forage would occur under all 

alternatives by construction of roads, drill pads, and ancillary facilities that remain in-use during the life 

of the project. Wild horse management concerns with development of gas resources on public lands in the 

CD-C project area include control of invasive, non-native weed species, reclamation success, rangeland 

improvement functionality, and dust from roads. In the past, reclamation efforts within the project area 

have been hampered by inadequate reclamation techniques and extended drought conditions. 

Indirect impacts of natural gas development on wild horses would include increased vehicle activity that 

could increase the potential for horse/vehicle collisions. If the Operators advise project personnel 

regarding appropriate speed limits on designated access roads, and these instructions are complied with, 

the likelihood of horse/vehicle collisions would be minimized. The level of risk for displacement of wild 

horses from the CD-C project area to areas outside HMA boundaries is unknown at the present time. 

There is some potential for wild horse conflict with wildlife/livestock. 

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4.10.3.1 Proposed Action 

Under the Proposed Action (Section 2.2.1), construction of 8,950 new natural gas wells and required 

ancillary facilities would be anticipated over the course of the 15 year development phase within the CDC project area. It is assumed that 42 percent of the wells (3,765) would be drilled from directional drilling 

pads. The Proposed Action is estimated to initially disturb a total of 47,200 surface acres (Table 4.0-1), 

which represents about 4.4 percent of the total land surface of the project area. Within this total, the initial 

disturbance acres for the Cyclone Rim allotment in the CD-C project area portion of the Lost Creek HMA 

is projected to be up to about 2,336 acres. Following successful reclamation, the long-term disturbance 

would be about 592 acres, representing a forage loss equivalent to approximately 69 AUMs (based on an 

average stocking ratio of 8.6 acres per AUM), less than 0.2 percent of the total forage in the allotment). 

The Proposed Action would also have a small effect on the Adobe Town HMA as the initial disturbed 

acres for the four allotments within the HMA would total an estimated 385 acres as follows: Continental, 

2 acres; Red Creek, 82 acres; South Flat Top, 301 acres; and Willow, 0 acres. Long-term surface 

disturbance is estimated at 101 acres, with an associated forage loss equivalent to 11.7 AUMs, less than 

0.1 percent of the total AUMs in the allotments. Because the relative loss of forage is so small, none of 

the allotments in either HMA would undergo a reduction in the amount of AUMs allocated. 

The level of risk for displacement of wild horses from the CD-C project area to areas outside the HMA 

boundaries is unknown at the present time. The opportunity for the public to view wild horses would not 

be affected. 

4.10.3.2 Alternative A: 100-Percent Vertical Drilling 

Alternative A (Section 2.2.2) is similar to the Proposed Action except this alternative assumes that no 

wells would be drilled using directional drilling rigs. Impacts to the vegetation resource resulting from 

implementation of Alternative A would be similar to the Proposed Action with the exception that the total 

amount of initial disturbed acres would increase from a total of 47,200 acres (Proposed Action) to 61,696 

acres (Alternative A). Within this total, the initial disturbance acres for the Cyclone Rim (Lost Creek 

HMA) allotment is projected to be about 3,037 acres. Following successful reclamation, the long-term 

disturbance would be about 770 acres, with an associated forage loss equivalent to approximately 90.0 

AUMs, less than 0.2 percent of the total forage in the allotment. 

Alternative A would have a small effect on the Adobe Town HMA as the initial disturbed acres for the 

four allotments within the CD-C portion of the HMA would total an estimated 503 acres as follows: 

Continental, 3 acres; Red Creek, 107 acres; South Flat Top, 393 acres; and Willow, 0 acres. Long-term 

surface disturbance is estimated at 107 acres, with an associated forage loss equivalent to 12.4 AUMs, 

less than 0.1 percent of the total AUMs in the allotments. Because the relative loss of forage is so small, 

none of the allotments in either HMA would undergo a reduction in the amount of AUMs allocated. 

4.10.3.3 Alternative B: Enhanced Resource Protection 

Alternative B was developed to avoid and/or mitigate significant impacts to specified resource values 

described in Section 2.2.3 by implementing additional protections and mitigations beyond those normally 

applied. The wild horse resource is not identified as one that would receive enhanced protection directly. 

However, the wild horse resource may indirectly benefit because livestock forage would be afforded 

enhanced protective measures to avoid reaching the significance criteria. These include mitigation of 

adverse impacts on water features, thorough power-washing of field vehicles to reduce the spread of 

invasive weeds, and control of fugitive dust from roads and production facilities, along with surface 

disturbance thresholds which trigger review of reclamation efforts and potentially range improvement 

projects. 

Impacts to wild horses resulting from implementation of Alternative B (Section 2.2.3) would be slightly 

less than the Proposed Action, decreasing from a total initial disturbance of 47,200 acres (Proposed 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—WILD HORSES
 

Action) to 45,516 acres (Alternative B). Within this total, the initial disturbance acres for the Cyclone 

Rim (Lost Creek HMA) allotment is projected to be about 2,253 acres. Following successful reclamation 

the long-term disturbance would be about 571 acres, with an associated forage loss equivalent to 

approximately 66.0 AUMs, less than 0.2 percent of the total forage in the allotment. 

Alternative B would have small effect on the Adobe Town HMA as the initial disturbance for the four 

allotments within the CD-C portion of the HMA would total an estimated 371 acres as follows: 

Continental, 2 acres; Red Creek, 79 acres; South Flat Top, 290 acres; and Willow, 0 acres. Long-term 

surface disturbance is estimated at 107 acres, with an associated forage loss equivalent to 12.4 AUMs. 

Because the relative loss of forage would be so small, none of the allotments in either HMA would 

undergo a reduction in the amount of AUMs allocated. 

4.10.3.4 Alternative C: Cap on Surface Disturbance, 60 Acres and 30 Acres per Section 

Under Alternative C (Section 2.2.4), the types of impacts to the wild horse resource would be similar to 

those described for the Proposed Action (Section 4.6.3.1) but the scope and intensity of the impacts 

would be less because of the surface cap restrictions. Total surface disturbance would be reduced from 

47,200 acres (Proposed Action) to 42,955 acres (Alternative C), a 9-percent reduction. 

Within this total, the initial disturbance acres for the Cyclone Rim (Lost Creek HMA) allotment is 

projected to be about 2,126 acres. Following successful reclamation, the long-term disturbance would be 

about 539 acres, with an associated forage loss equivalent to approximately 63.0 AUMs, less than 0.2 

percent of the total forage in the allotment. 

Alternative C would have a small effect on the Adobe Town HMA as the initial disturbance for the four 

allotments within the CD-C portion of the HMA would total an estimated 351 acres as follows: 

Continental, 2 acres; Red Creek, 75 acres; South Flat Top, 274 acres; and Willow, 0 acres. Long-term 

surface disturbance is estimated at 92 acres, with an associated forage loss equivalent to 10.7 AUMs. 

Because the relative loss of forage would be so small, none of the allotments in either HMA would 

undergo a reduction in the amount of AUMs allocated. 

4.10.3.5 Alternative D: Directional Drilling 

Under Alternative D (Section 2.2.5), the types of impacts to the wild horse resource would be similar to 

those described for the Proposed Action (Section 4.6.3.1) but the scope and intensity of the impacts 

would be less widespread because of the expected reduction in surface disturbance. Estimated projectwide, initial surface disturbance for this alternative would be approximately 36,449 acres, a decrease of 

10,751 acres (23 percent) from the Proposed Action. The initial forage lost under this alternative is 

estimated to be 1,131 AUMs less than the Proposed Action. The estimated 14,952 acres of long-term 

disturbance is estimated to be 3,908 acres less than the Proposed Action, representing about 411 fewer 

AUMs lost than the Proposed Action. 

Although it is not known at the present time where future multi-well pads would be located in the 

Cyclone Rim allotment in the CD-C project area portion of the Lost Creek HMA, the estimated maximum 

initial disturbance within the Cyclone Rim allotment would be approximately 164 acres, which represents 

the equivalent of about a 19 AUM loss for the allotment. Following successful reclamation, the long-term 

disturbance would be about 80 acres, representing a forage loss equivalent to approximately 9 AUMs 

(based on an average stocking ratio of 8.6 acres per AUM). 

It may also be assumed that with fewer well pads developed, there would be similar reductions in the 

number of access roads and road miles within the allotment which would decrease the potential for wild 

horse/vehicle collision hazards, as well as reduced human presence and reduced fugitive dust generation. 

Alternative D would have a small effect (if any) on the Adobe Town HMA because of the small amount 

of acreage involved (see 4.10.3.1). Because the relative loss of forage is so small, none of the four 

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allotments in the Adobe Town HMA or the Lost Creek HMA within the Cyclone Rim allotment would 

undergo a reduction in the amount of AUMs allocated. 

4.10.3.6 Alternative E: No Action 

Under the No Action Alternative it is assumed that no further natural gas development would occur 

within the CD-C project area and there would be no new disturbance except where APDs have been 

approved by the BLM for previously authorized activities. 

4.10.4 Impacts Summary 

Impacts to wild horses associated with the action alternatives would include disturbed land and associated 

loss of available forage. Implementation of the Proposed Action would result in an initial loss of forage 

equivalent to approximately 69 AUMs within the project-area portion of the Lost Creek HMA, less than 

0.2 percent of the total forage in the allotment. The Proposed Action would also have only a small effect 

on the Adobe Town HMA as the forage loss would be equivalent to 11.4 AUMs, less than 0.1 percent of 

the total AUMs in the allotments. Because the relative loss of forage would be so small, none of the 

allotments in either HMA would undergo a reduction in the amount of AUMs allocated. 

The alternatives to the Proposed Action would generally affect wild horses to a greater or lesser degree 

than the Proposed Action according to the increase or decrease in surface disturbance that would result 

from the alternative. However, because the relative loss of forage would be so small in each case, none of 

the allotments in either HMA would undergo a reduction in the amount of AUMs allocated. The No 

Action Alternative would have the least impact upon wild horses because virtually none of the land in 

either HMA would be developed. 

Incentives for successful reclamation, which are featured components of Alternative C, would be a 

positive impact to wild horses because it rewards timely reclamation, which can prevent and contain 

invasive species, thus reducing competition with native plants and consequently maximizing forage 

production. 

Under Alternative D, it may be assumed that with the fewer well pads developed, there would be similar 

reductions in the number of access roads and road miles within the affected allotments which would 

decrease the potential of wild horse/vehicle collision hazards, as well as reduced human presence and 

reduced fugitive-dust generation, all of which would benefit the wild horse resource. 

None of the alternatives would affect the opportunity for the public to view wild horses. 

The risk of displacement of wild horses from the CD-C project area to areas outside the HMA boundaries 

is unknown at the present time. 

Wild horse conflict with wildlife and livestock would be minimized provided the current AMLs for both 

HMAs are closely monitored and regulated by periodic gather-and-removal cycles. 

4.10.5 Unavoidable Adverse Impacts and Additional Mitigation Measures 

No measurable unavoidable adverse impacts on the area’s wild horse herds are expected under the 

Proposed Action or the other alternatives. However, one additional mitigation measure may further 

minimize the likelihood of impact on the herds. The Operators could enhance wild horse welfare by 

addressing the importance of the Wild Free-Roaming Horse and Burro Act of 1971 (Public Law 92-195) 

at all new-employee orientations. Such orientations would stress the fact that wild horses are federally 

protected and it is a violation of the Act to harass, injure, or destroy them, and that violations may result 

in citations being issued as appropriate. In addition, a violation of the Act would be considered a 

significant project impact by the BLM (Section 4.10.3). Overall avoidance of wild horses is the best 

policy to prevent unnecessary displacement and agitation of the horses and potential separation of small 

foals from their mares during the foaling season. 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—VISUAL RESOURCES 

 HUMAN ENVIRONMENT 

4.11 VISUAL RESOURCES 

4.11.1 Introduction 

As described in Chapter 3, Affected Environment, the BLM manages approximately 60 percent of the 

CD-C project area as Visual Resource Management (VRM) Class III and approximately 40 percent as 

VRM Class IV. Chapter 3 identified the management objectives for the VRM class designations found in 

the project area as the following: 

Class III. The objective of Class III is to partially retain the existing character of the landscape. The level 

of change to the landscape should be moderate. Management activities may attract the attention of the 

casual observer but should not dominate the view of the casual observer. Changes should repeat the basic 

elements found in the predominant natural features of the characteristic landscape. 

Class IV. The objective of Class IV is to provide for management activities that require major 

modifications to the existing character of the landscape. The level of change to the landscape can be high. 

The management activities may dominate the view and may be the major focus of viewer attention. Every 

attempt should be made to minimize the impact of these activities through careful location, minimal 

disturbance, and repetition of the basic visual elements of form, line, color, and texture. 

In other words, Class III and IV areas are intended for surface-disturbing activities that respectively cause 

moderate and high levels of landscape alteration. This summarizes the management guidance for VRM 

that appears in Appendix 25 of the ROD for the Rawlins RMP (BLM 2008b). 

4.11.2 Management Objectives and Impact Significance Criteria 

The Rawlins RMP (BLM 2008a) lists the following management objectives for visual resources: 

1.	 Establish VRM classes for the RMPPA. 

2.	 Maintain the overall integrity of visual resource classes while allowing for development of existing 

and future uses. 

Impacts to visual resources would be considered significant if the RFO is unable to meet the management 

objective for VRM established in the approved RMP, namely to “maintain the overall integrity of visual 

resource classes while allowing for development of existing and future uses” (Record of Decision and 

Approved Rawlins RMP, p. 2-48). This means that for the BLM to allow oil and gas development and 

production facilities within VRM Class III, the landscape change introduced by development must be 

moderate or reduced to moderate by mitigation in the form of BMPs as conditions of approval (Rawlins 

RMP FEIS, 4-393). Within VRM Class IV, the BLM permits oil and gas development and production 

facilities without additional mitigation because VRM Class IV allows for major modification of the 

existing landscape. However, the BLM does review individual permit applications in VRM Class IV and 

can ask oil and gas operators to voluntarily use the basic visual impact mitigation methods of adjustment 

in the siting of facilities, painting of facilities to reduce contrast with the natural landscape, and 

minimizing the amount of surface disturbance caused by construction and operations. 

The impact analysis is based on interdisciplinary team knowledge of resources and the project area, 

review of existing BLM documents, and information provided by other agencies. Map 3.11-1 presents 

VRM classes for the project area, and Table 3.11-1 presents acreages for each VRM class. To compare 

the alternatives in terms of impact severity, the analysis uses the amount of initial and long-term surface 

disturbance presented in Table 2.4-1 as a direct indicator. 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—VISUAL RESOURCES 

4.11.3 Direct and Indirect Impacts 

4.11.3.1 Proposed Action 

Under the Proposed Action, the RFO would be able to meet its management objective for VRM within 

the project area. This is based upon the RFO’s experience with development that has occurred in the 

project area to date. 

The Proposed Action would create initial surface disturbance of 47,200 acres, or 4.4 percent of the project 

area. Most of the initial disturbance would be for well pads, structures, and roads. Interim reclamation 

would reduce surface disturbance to 18,861 acres, or 1.8 percent of the project area, which would remain 

as open disturbance for the life of the project, after which facilities would be removed and final 

reclamation would begin. 

The RFO approach to mitigating the effects of oil and gas development to visual resources is to first 

enforce operator commitments to particular BMPs. Additional BMPs may be added as Conditions of 

Approval (COAs) on a site-specific basis in VRM Class III (Section 2.2.1.7 Operator-Committed 

Practices). This would mitigate the impact to the landscape and keep landscape modification at a 

moderate level. 

As noted in Appendix C, BLM may require BMPs as COAs for APDs and other site-specific permits. 

Requirements or requests for site-specific mitigation occur during the review and NEPA analysis of 

APDs, right-of-way applications, and other individual permit applications. 

As described in Section 4.11.2, oil and gas development and production facilities would be compatible 

with VRM Class III management objectives when the development, including adequate mitigation, yields 

a moderate level of landscape modification. Figure 4.11.1 illustrates the moderate contrast introduced by 

development of a single natural gas production site, viewed in the foreground from a public road. The 

structures remain below the horizon line and are all painted in one suitable color, and the site and related 

roads have been reduced to the minimum adequate and safe size. 

Figure 4.11.1. Example of existing site in the project area 

In its analysis of the RMPPA, BLM anticipated that meeting VRM objectives would affect the placement 

of facilities associated with minerals exploration and development. This would exert a definite influence 

on finding acceptable locations where development might occur as well as the size and coloration of 

facilities depending on the visual class and location (Minerals, Rawlins RMP FEIS p. 4-87). 

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Since the project is an infill development in an existing natural gas field, new road construction would not 

be extensive. The primary access to the project area is I-80. Existing arterial roads, including WY 789 and 

several Sweetwater and Carbon county roads, provide access within the project area. New road 

construction would primarily be short sections of road from the existing road network to the individual 

new well sites and support facilities. Some existing access roads may need to be improved to 

accommodate increased traffic. At the project scale, incremental road development would be low for a 

project of this size, which means a relatively low level of surface disturbance. 

At the site-specific level within VRM Class III, individual facilities may modify the visual character of a 

view from a given “key observation point” (KOP) such that BMPs other than those explicitly committed 

to by the Operator may be needed for adequate mitigation (see Appendix C for the full list of BMPs). 

BLM may impose additional BMPs as COAs to site-specific permits. However, some BMPs that involve 

facility siting, road alignment, and the scale or configuration of equipment would have to be evaluated in 

each case for consistency with prior terms of valid minerals leases. 

Despite operator-committed practices, oil and gas development under the Proposed Action would 

unavoidably affect the visual resources of the project area by modifying the landscape (Figure 4.11.1). 

Development removes existing vegetation, replacing it with bare ground, graveled roads and pads, and 

structures related to drilling and production. The “built” forms, lines, colors, and textures contrast with 

natural landscape elements, though mitigation can reduce the level of contrast. 

In addition, as described in Section 4.11.3, oil and gas development is compatible per se with VRM Class 

IV management objectives because a designation of VRM Class IV determines that major modification of 

the existing character of the landscape would be permitted. At the level of a large-scale development such 

as that proposed for the project area, this is a categorical determination. In effect, the designation of areas 

as VRM Class III or VRM Class IV reflects a planning level (RMP) decision to allow oil and gas 

development to affect visual resources, subject to more individualized and site-specific conditions of 

approval in VRM Class III that can only be determined once site-specific permitting begins. 

Operator implementation of BMPs would lower the visual impact of site-specific development even in the 

VRM Class IV part of the project area. Committed BMPs include interim reclamation of well locations 

and access roads, painting new facilities with a suitable environmental color, and building new roads to a 

“no higher than necessary” standard which reduces surface disturbance. Despite the application of 

committed BMPs, a high level of change could occur under the Proposed Action in the parts of the project 

area that are in VRM Class IV but are still relatively natural. In such areas, oil and gas facilities could 

dominate the view of even the casual observer and perhaps discourage or displace activities for which a 

setting with natural character is desired. 

Section 3.11.3 described how, in parts of the project area where public and private land-ownership is 

intermingled in a “checkerboard” pattern, much of the private land may not be subject to BLM 

administration. The BLM’s authority over visual resources extends only to where BLM owns the surface 

or the oil and gas beneath the surface. In the checkerboard specifically and wherever non-BLM inholdings exist, the BLM would mitigate the visual impact of development on the BLM-administered 

surface as best it can and would encourage oil and gas developers to apply comparable mitigation to 

adjacent privately owned surface. Development not managed by the BLM that occurs on non-BLM 

sections in the checkerboard or other in-holdings may not attain BLM standards and so may indirectly 

degrade the appearance of the landscape on the BLM land. 

Oil and gas development would be quite apparent from the road network in the project area. The road 

network of the project area is extensive, so any development visible from an established road would be in 

the foreground to middle ground of the view from (i.e., within 5 miles of) the road (BLM 2011a). 

The site-specific analysis called for in permitting APDs and other individual development proposals 

contained within the Proposed Action would require the selection of KOPs. A KOP is a proxy for the 

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location of a casual viewer sensitive to scenic quality. All KOPs in the project area are likely to be on the 

state, county, and BLM roads used by hunters, sightseers, and wildlife watchers. Table 4.11-1 lists the 

roads in the project area that access Class III areas in the northern and southern part of the project area. 

BLM would consider the view of a well site, road, or other facility from identifiable KOPs during the sitespecific analysis of the application for a permit. 

Table 4.11-1.	 Roads accessing VRM Class III in the CD-C project area where users would likely see oil 

and gas facilities under the action alternatives 

Northern part of project area Southern part of project area 

Road Common Name Road Common Name 

CR 20 Luman Road WY 789 Baggs–Creston Junction Highway 

CR 23N Wamsutter–Crooks Gap Road BLM 3216 Robbers Gulch Road 

CR 67 Tipton (North) Road BLM 3321 Little Robbers Gulch Reservoir Road 

BLM 3207 Red Desert Road -- --

Notes: 

1. All county roads are in Sweetwater County. 

2. All roads would likely access foreground to middle-ground views of facilities within 3 to 5 miles or less of the viewer. 

Given successful final reclamation, impacts to visual resources are not irretrievable. However, they are 

long term. During the process of final reclamation of the Proposed Action, reclaimed land would 

potentially present evidence of disturbance that would have a residual effect on scenic quality until 

vegetative treatments mature. The road network would contribute the most to this type of impact; even 

reclaimed roads may present obviously intrusive linear features on the project area landscape lasting long 

after the life of the project. 

4.11.3.2 Alternative A: 100-Percent Vertical Drilling 

Allowing 100-percent vertical drilling (one well per pad) would increase the visual impacts of 

development. In the short term, Alternative A would disturb 61,696 acres, or 5.8 percent of the project 

area. This is 31 percent more initial disturbance than would be caused by the Proposed Action. The types 

of facilities causing impacts and the qualitative character of impacts would be the same as described for 

the Proposed Action. 

Interim reclamation would reduce surface disturbance to 24,133 acres, or 2.3 percent of the project area, 

which would remain open for the life of the project under Alternative A, after which facilities would be 

removed and final reclamation would begin. Alternative A would cause about 28 percent more long-term 

disturbance than the Proposed Action. The likelihood of casual observers encountering visual impacts to 

views within the project area would be higher roughly in proportion to the greater amount of disturbance. 

The compatibility of Alternative A with BLM’s VRM objectives would be the same as for the Proposed 

Action. Adequate visual mitigation in the form of BMPs and COAs would allow oil and gas development 

to be compatible with VRM Class III, which allows up to moderate change to existing landscape 

character. Oil and gas development is compatible per se with VRM Class IV, which allows for major 

modification to existing landscape character. 

4.11.3.3 Alternative B: Enhanced Resource Protection 

Alternative B would slightly decrease the potential for visual impacts of development compared to the 

Proposed Action. In the short term, Alternative B would disturb 45,516 acres, or 4.3 percent of the project 

area. This is 4 percent less initial disturbance than for the Proposed Action. The kinds of facilities causing 

impacts and the qualitative character of impacts would be the same as described for the Proposed Action. 

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Interim reclamation would reduce surface disturbance to 18,249 acres, or 1.7 percent of the project area, 

that would remain open for the life of the project under Alternative B, after which facilities would be 

removed and final reclamation would begin. Alternative B would cause about 3.0 percent less long-term 

disturbance than the Proposed Action. The likelihood of casual observers encountering visual impacts to 

views within the project area would be roughly the same for Alternative B as for the Proposed Action. 

The compatibility of Alternative B with BLM’s VRM objectives would be the same as for the Proposed 

Action. Adequate visual mitigation in the form of BMPs and COAs would allow oil and gas development 

to be compatible with VRM Class III, which allows for moderate change to existing landscape character. 

Oil and gas development is compatible per se with VRM Class IV, which allows for major modification 

to existing landscape character. 

Under Alternative B, enhanced protection measures for biological resources would reduce impacts to 

visual resources because of their broad aim to reduce surface disturbance. Measures to minimize 

biological disturbance of the Chain Lakes Alkaline Wetlands and Other Playas would particularly benefit 

scenic quality because these features characterize the natural landscape of the northern part of the project 

area (BLM 2011a). 

4.11.3.4 Alternative C: Surface Disturbance Cap, High and Low Density Development Areas 

Alternative C would modestly decrease the potential for visual impacts of development, compared to the 

Proposed Action. In the short term, Alternative C would disturb 42,955 acres, or 4.0 percent of the project 

area. This is 9.0 percent less initial disturbance than for the Proposed Action. The kinds of facilities 

causing impacts and the qualitative character of impacts would be the same as described for the Proposed 

Action. 

Interim reclamation under Alternative C would reduce surface disturbance to 17,318 acres, or 1.6 percent 

of the project area, which would remain open for the life of the project, after which facilities would be 

removed and final reclamation would begin. Alternative C would cause about 8.0 percent less long-term 

disturbance than the Proposed Action. The likelihood of casual observers encountering visual impacts to 

views within the project area would be slightly less for Alternative C than for the Proposed Action. 

The compatibility of Alternative C with BLM’s VRM objectives would be the same as for the Proposed 

Action. Adequate visual mitigation in the form of BMPs and conditions of approval would allow oil and 

gas development to be compatible with VRM Class III, which allows up to moderate change to existing 

landscape character. Oil and gas development is compatible per se with VRM Class IV, which allows for 

major modification to existing landscape character. 

The surface-disturbance caps under Alternative C would put an upper limit on the impact to scenic quality 

that would occur at points in time during the life of the project. 

4.11.3.5 Alternative D: Directional Drilling 

Alternative D would decrease the the potential for visual impacts of development, compared to the 

Proposed Action. In the short term, Alternative D would disturb 36,449 acres, or 3.4 percent of the project 

area. This is 23 percent less initial disturbance than for the Proposed Action. The kinds of facilities 

causing impacts and the qualitative character of impacts would be as described for the Proposed Action. 

Interim reclamation would reduce surface disturbance to 14,952 acres, or 1.4 percent of the project area, 

that would remain open for the life of the project under Alternative D, after which facilities would be 

removed and final reclamation would begin. Alternative D would cause about 21 percent less long-term 

disturbance than the Proposed Action. 

The compatibility of Alternative D with BLM’s VRM objectives would be the same as for the Proposed 

Action. Adequate visual mitigation in the form of BMPs and conditions of approval would allow oil and 

gas development to be compatible with VRM Class III, which allows up to moderate change to existing 

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landscape character. Oil and gas development is compatible per se with VRM Class IV, which allows for 

major modifications to existing landscape character. 

The likelihood of casual observers encountering visual impacts to views within the project area would be 

less for Alternative D than for the Proposed Action. In addition, if Alternative D achieves fewer and less 

densely distributed well pads and fewer associated roads, pipelines, and other facilities, a casual viewer 

observing from points along the interior road network of the project area may encounter oil and gas 

related disturbance somewhat less frequently because of the wider distribution of pads and related 

development. 

This would benefit parts of the CD-C project area, especially those located in VRM Class III. When 

combined with less surface disturbance overall, the probability that a more compact pattern of 

development would be seen somewhat less often as a visitor moves through the landscape could lead 

casual viewers to be more accepting of modification to the existing character of the landscape. Thus, 

development under Alternative D could be more consistent with the management objective of landscape 

retention in areas now rated VRM Class III. 

4.11.3.6 Alternative E: No Action 

Under Alternative E, none of the impacts to visual resources described under the Proposed Action or 

under Alternative A through Alternative D would occur. The key assumption for the analysis of 

Alternative E is that no further oil and gas development would occur in the project area and there would 

be no further change to the existing character of the landscape as a result of new oil and gas development. 

In addition, as oil and gas facilities gradually become obsolete over time, much of the project area now 

affected by oil and gas development would gradually return to a more natural-appearing scenic quality, 

assuming the success of past reclamation planning and its implementation in the future. 

The likelihood of casual observers encountering visual impacts to views within the project area because 

of oil and gas development would, over time, gradually become less than today for Alternative E and 

much less in the long term than for the Proposed Action, because it is assumed that Alternative E would 

lead to no new oil and gas development and that existing oil and gas facilities would eventually become 

obsolete and be reclaimed. 

4.11.4 Impact Summary 

Compared to the Proposed Action,less degradation of landscape quality would occur under Alternatives 

B, C, and D and more would occur under Alternative A. Under Alternative E, no new oil and gas 

development would occur, and there would be no further change to the existing character of the landscape 

because of new development. 

The character of the surface disturbance and the character of the impacts to visual resources would be 

similar under all action alternatives because they would consist in all cases of drill sites and equipment, 

production pads and facilities, access roads, and utilities. The level of impact to landscape quality would 

vary roughly in proportion to the difference among the alternatives in terms of the level of development 

and the resulting amount of initial and long-term surface disturbance. Under Alternative E, No Action, 

much of the project area now affected by existing oil and gas development would gradually return to a 

more natural-appearing scenic quality, assuming reclamation success over time. 

4.11.5 Unavoidable Adverse Impacts and Additional Mitigation Measures 

The Proposed Action and alternatives would create contrasting lines, forms, colors, and textures in the 

landscape through the removal of existing vegetation and the introduction of drilling and production 

facilities and access roads. Visual resources would be unavoidably adversely impacted for the life of the 

project and beyond until the surface has returned to a condition that is comparable to the surrounding 

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natural area. The level of contrast would be more evident in areas with little or no current energy 

development. 

Approximately 60 percent of the project area is managed as VRM Class III, where the level of change 

must be moderate or reduced to moderate using mitigation measures, operator-committed measures, and 

BMPs applied at the discretion of the RFO as conditions of approval for site-specific APDs. The 

remaining 40 percent of the project area is managed as VRM Class IV, where major modifications of the 

landscape are allowed. Because both VRM Class III and Class IV allow for modification of the landscape, 

no additional visual mitigation measures would be necessary for the CD-C project. 

4.11.6 Effect of the VRM Amendment to the Resource Management Plan 

As noted in Section 3.11.4, the RFO must use the existing 1990 VRM classifications to manage visual 

resources in the CD-C project area. However, the BLM has begun the VRM-RMP amendment process 

and intends to finalize the VRM amendment to the RMP by the end of 2013 (Section 3.11.5). A VRM 

amendment may lead to changes in the classification of land within the CD-C project area, based on the 

findings of the 2011 visual resource inventory (Section 3.11.3). 

Changes to the classification of land within the CD-C project area could affect the analysis of impacts to 

visual resources in terms of how many acres of land are governed by the management objectives of VRM 

Class III or VRM Class IV. In its decision on the CD-C project, the BLM would seek to attain the 

management objectives for each VRM class that is in effect. 

4.12 RECREATION 

4.12.1 Introduction 

This section presents impacts to recreation from the Proposed Action and alternatives. Recreational uses 

on public lands administered by the BLM within the project area include hunting, off-highway vehicle 

(OHV) use, wildlife viewing, and pleasure driving on public roads. The affected environment for 

recreation resources is described in Section 3.12, Recreation, with recreation features of the project area 

illustrated in Map 3.12.1. 

4.12.2 Management Objectives and Impact Significance Criteria 

The Rawlins RMP (BLM 2008a) lists the following management objectives for recreation resources: 

1.	 Provide for the health and safety of visitors. 

2.	 Prevent or mitigate resource damage resulting from recreation uses. 

3.	 Coordinate with other programs to minimize conflicts and adverse impacts on recreational 

opportunities.
 

4.	 In the Western Extensive Recreation Management Area (ERMA), consider the above recreation 

objectives during development involving surface-disturbing or disruptive activity. Consider the 

Adobe Town Dispersed Recreation Management Area desired future condition during development 

involving surface-disturbing or disruptive activity. 

5.	 In the Eastern ERMA (RMP Map 2-17), retain the quality of dispersed recreation opportunities and 

settings (with the exception of isolated development areas, such as coal mines or wind generation 

facilities) while meeting the above recreation objectives. 

6. Provide public education regarding appropriate use of BLM lands. 

7. Provide opportunities for public use, interpretation, education, and appreciation of natural and 

cultural resources. 

Impacts to recreation would be considered significant if any of the following were to occur: 

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1.	 Management actions result in long-term elimination or reduction of recreation use in any area or 

compromise public health and safety.
 

2.	 Intensity of development is incompatible with the stated objectives of Special Recreation 

Management Areas (SRMAs). 

3.	 Increases in recreational activity create substantial risks to public health and safety or resource 

damage. 

4.12.3 Direct and Indirect Impacts 

4.12.3.1 Proposed Action 

Under the Proposed Action, the RFO would be able to meet its management objectives for recreation 

within the project area. This is because the Operators have incorporated IM WY-2004-194, Integration of 

Best Management Practices into Application for Permit to Drill Approvals and Associated Rights-ofWay. The Operators cite this IM as prompting their commitment to considering several BMPs in nearly 

all circumstances during development. Several of the cited BMPs would have the effect of lowering 

surface disturbance (Section 2.2.1.7 Operator-Committed Practices). Lowering surface disturbance 

would lower impacts to big-game wildlife (see Section 4.8 Wildlife), and lower impacts to big game 

would in turn indirectly lower impacts to hunting, the main recreation activity that currently exists in the 

project area. 

Pursuant to a general agreement with the WGFD, the Approved RMP directs the BLM to intensively 

manage surface-disturbing and disruptive activities to reduce impacts to wildlife (Rawlins RMP 2-33). 

Interactions with the WGFD over management of development’s impacts to wildlife under the Proposed 

Action would also indirectly lower impacts to hunting recreation. 

In addition, BMPs that lower surface disturbance would reduce impacts to visual resources. Lower 

impacts to visual resources would indirectly reduce impacts to recreation settings, which in turn would 

indirectly reduce impacts to hunting and to non-consumptive, dispersed recreation in the project area such 

as wildlife observation, OHV recreation, and driving for pleasure. 

The level of impact to recreation from the Proposed Action would correlate with measures of surface 

disturbance. The Proposed Action would create initial surface disturbance of 47,200 acres, or 4.4 percent 

of the project area. Most of the initial disturbance would be for well pads, structures, and roads. Interim 

reclamation would reduce surface disturbance to 18,861 acres, or 1.8 percent of the project area, which 

would remain as open disturbance for the life of the project, after which facilities would be removed and 

final reclamation would begin. 

Despite Operator-committed practices, oil and gas development under the Proposed Action would 

unavoidably affect recreation resources of the project area by modifying supplemental values important 

for recreation quality. As part of the natural gas development process, new roads could create access to 

areas that previously were not used for recreation. However, the industrial character associated with oil 

and gas activity introduces contrasting elements affecting scenic quality, which would displace some 

recreationists to other areas. Supplemental values and resources such as scenic quality, solitude, and 

wildlife would be degraded and would interfere with recreationists’ goals and experiences. Eventually, 

successful final reclamation would rehabilitate the recreation settings to be found in the project area. 

However, the time needed to accomplish this would potentially span more than one generation of 

recreatoinists. 

Overall, the intensity of impacts to recreation under the Proposed Action would vary roughly in 

proportion to the change in the density of well development. In addition, impact intensity would vary 

within the project area depending on the extent of new well development as compared to the density of 

existing development. 

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Thus, the intensity of impacts to recreation would be highest in the northern part of the project area, 

where natural gas development is less dense to date and where the Chain Lakes WHMA and the large 

block of public land northwest of the WHMA are a resource for big game hunting and other wildlifebased recreation. Similarly, impacts to the WGFD Carbon County Walk-In Area #1 would be relatively 

high because less development has occurred to date in this part of the project area. 

Natural gas development raises health and safety issues for the BLM because of conflict that may arise 

between industrial traffic and recreational traffic. The hazard associated with road use would potentially 

rise in proportion to the amount of gas development, plus the trend in recreational use. 

At Little Robbers Gulch Reservoir in the southern part of the project area, unrestricted surface-disturbing 

activity nearby would degrade the setting of the undeveloped recreation site. However, low water levels 

in the agricultural reservoir have already degraded the site’s appeal as a fishing hole and group campsite 

during hunting season, meaning that further degradation of the setting at the reservoir may have less 

importance to recreationists because of the already declining usage for other reasons. 

Recreation use displaced from the project area could find substitute opportunities elsewhere within the 

RFO or in adjoining BLM field offices. This applies equally to hunting, wildlife viewing, and pleasure 

driving. However, these resources would likely be farther away for recreationists who now use the CD-C 

project area; additionally, resources elsewhere may themselves be under increasing pressure from fluid 

minerals development and development of other resources potentially conflicting with recreation. 

4.12.3.2 Alternative A: 100-Percent Vertical Drilling 

With 100-percent vertical drilling (one well per pad) there would be no reduction of surface disturbance 

as there would be from using directional drilling and pads with multiple wells. Alternative A would 

disturb 61,696 acres in the short term, which is 5.8 percent of the project area. This is 31 percent more 

initial disturbance than would be caused by the Proposed Action. 

Interim reclamation would reduce un-revegetated surface disturbance to 24,133 acres (2.3 percent of the 

project area); this would remain open for the life of the project under Alternative A, after which facilities 

would be removed and final reclamation would begin. Alternative A would cause about 28 percent more 

long-term disturbance than the Proposed Action. The types of facilities causing impacts and the 

qualitative character of impacts would be the same as described for the Proposed Action. 

The relative intensity of impacts to recreation would be highest in the parts of the project area where 

previous well density has been no more than one or two wells per section. The likelihood of impacts to 

recreation would be higher roughly in proportion to the greater amount of disturbance and rise in well 

density. 

4.12.3.3 Alternative B: Enhanced Resource Protection 

Alternative B Enhanced Resource Protection would slightly decrease the potential for impacts to 

recreation compared to the Proposed Action. In the short term, Alternative B would disturb 45,516 acres, 

or 4.3 percent of the project area. This is 4 percent less initial disturbance than for the Proposed Action. 

The types of facilities causing impacts and the qualitative character of impacts would be the same as 

described for the Proposed Action. 

Interim reclamation under Alternative B would reduce surface disturbance to 18,249 acres (1.7 percent of 

the project area); this would remain open for the life of the project, after which facilities would be 

removed and final reclamation would begin. Alternative B would cause about 3 percent less long-term 

disturbance than the Proposed Action. 

Under Alternative B, impacts would be more apparent in the parts of the project area where previous well 

density has been no more than one or two wells per section. The likelihood of impacts to recreation would 

be roughly the same for Alternative B as for the Proposed Action. However, specific measures to benefit 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—RECREATION
 

big game wildlife habitat that are among the enhanced protections included in Alternative B may provide 

some additional mitigation of impacts to wildlife and in turn reduce impacts to the hunting-based 

recreation that predominates in the project area. 

4.12.3.4 Alternative C: Surface Disturbance Cap, High and Low Density Development Areas 

Alternative C would modestly decrease the potential for recreation impacts from development, compared 

to the Proposed Action. In the short term, Alternative C would disturb 42,955 acres, or 4 percent of the 

project area. This is 9 percent less initial disturbance than for the Proposed Action. The types of facilities 

causing impacts and the qualitative character of impacts would be the same as described for the Proposed 

Action. 

Interim reclamation under Alternative C would reduce surface disturbance to 17,318 acres, or 1.6 percent 

of the project area, which would remain open for the life of the project, after which facilities would be 

removed and final reclamation would begin. Alternative C would cause about 8 percent less long-term 

disturbance than the Proposed Action. 

The likelihood of impacts to recreation would be higher roughly in proportion to the greater amount of 

disturbance. However, the surface disturbance caps under Alternative C would put an upper limit on the 

impact to recreation that would occur at points in time during the life of the project. 

4.12.3.5 Alternative D: Directional Drilling 

Alternative D would decrease the potential for recreation impacts, compared to the Proposed Action. In 

the short term, Alternative D would disturb 36,449 acres, or 3.4 percent of the project area. This is 23 

percent less initial disturbance than for the Proposed Action. The kinds of facilities causing impacts and 

the qualitative character of impacts would be as described for the Proposed Action. 

Interim reclamation would reduce surface disturbance to 14,952 acres, or 1.4 percent of the project area; 

this would remain open for the life of the project under Alternative D, after which facilities would be 

removed and final reclamation would begin. Alternative D would cause about 21 percent less long-term 

disturbance than the Proposed Action. 

The likelihood of impacts to recreation within the project area would be somewhat less for Alternative D 

than for the Proposed Action. Alternative D further lowers surface disturbance and therefore lowers the 

direct loss of habitat, improving the chance of retaining herd sizes in the CD-C project area. A more 

compact pattern of development under Alternative D would also benefit big game wildlife management 

long term by lowering habitat fragmentation and disturbance from human activity because fewer well pad 

access roads would be constructed. The benefit to big game wildlife management under Alternative D 

would lower the impact to hunting recreation during the life of the project. 

4.12.3.6 Alternative E: No Action 

Under Alternative E, none of the impacts to recreation described under the Proposed Action and 

Alternatives A through D would occur, so there would be no further change to recreation resources in the 

CD-C project area because of new oil and gas development. In addition, as existing oil and gas facilities 

gradually become obsolete over time, those parts of the project area now affected by oil and gas 

development could gradually return to a reclaimed condition that is intended to attain a more naturalfunctioning character. The effect of reclaiming obsolete oil and gas facilities could be positive for the 

recreation resource if the current trend toward habitat loss, degradation of recreation settings, and growth 

in human intrusion is stabilized for a number of years or perhaps reversed to some degree. 

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4.12.4 Impact Summary 

Under the Proposed Action, the RFO would be able to meet its management objective for recreation 

within the project area because the project area is within the RFO’s Western ERMA, where restriction or 

avoidance of surface-disturbing and disruptive activities to protect recreation is not required by the 

Rawlins RMP. Consistent with the RMP’s management prescription for the Western ERMA, the 

Operators have incorporated BLM IM 2004-194, Integration of Best Management Practices into 

Application for Permit to Drill Approvals and Associated Rights-of-Way. Operator-committed practices 

noted in Section 2.2.1.7 Operator-Committed Practices would lower surface disturbance, impacts to 

big game, and indirectly the impacts to hunting, the main recreation activity in the project area. 

The intensity of impacts to recreation from the Proposed Action and other action alternatives would 

correlate to the variation in long-term surface disturbance by alternative: 

 Proposed Action—18,861 acres (1.8 percent of the project area) 

 Alternative A: 100-Percent Vertical Drilling—24,133 acres (2.3 percent of the project area) 

 Alternative B: Enhanced Resource Protection—18,249 acres (1.7 percent of the project area) 

 Alternative C: Cap on Surface Disturbance, 60 Acres and 30 Acres per Section —17,318 acres (1.6 

percent of the project area)
 

 Alternative D: Directional Drilling—14,952 acres (1.4 percent of the project area) 

Under Alternative E, none of the impacts to recreation described under the Proposed Action and 

Alternatives A through D would occur. Thus, there would be no further change to recreation resources in 

the CD-C project area because of new oil and gas development. As existing oil and gas facilities gradually 

become obsolete over time and are reclaimed, the effect could be positive for the quality of the recreation 

resource. 

4.12.5 Unavoidable Adverse Impacts and Additional Mitigation Measures 

The Proposed Action and alternatives may result in a reduction or long-term elimination of recreation— 

most notably hunting—within portions of the project area that are directly affected by short-term or longterm surface disturbance. Impacts to big game as a result of the Proposed Action and alternatives may 

also indirectly impact hunting and wildlife viewing. However, because the project area lies entirely within 

the RFO’s Western ERMA, the Rawlins RMP does not require restrictions or avoidance of surfacedisturbing or disruptive activities to protect recreation. No additional mitigation would be required 

beyond Operator-committed measures and BMPs. 

4.13 LANDS WITH WILDERNESS CHARACTERISTICS 

No Lands with Wilderness Characteristics (LWCs) are located within the boundaries of the CD-C project 

area. Therefore, the Proposed Action and alternatives are in compliance with the RMP, which provides 

for oil and gas development on multiple-use lands within the RFO, subject to BLM approval and 

permitting. 

As directed by BLM Manual Sections 6310 and 6320 (BLM 2012f, 2012g),21 and in compliance with 

FLPMA Sections 201 and 202, the RFO will maintain the inventory of LWCs on a continuing basis and 

21 Instruction Memorandum (IM) No. 2011-154 , dated July 25, 2011, and transmitted July 26,2011, directs offices to continue to 

conduct and maintain inventories regarding the presence or absence of wilderness characteristics, and to consider identified lands 

with wilderness characteristics in land use plans and when analyzing projects under NEPA. The IM places BLM Manuals 6301, 

6302, and 6303, dated February 25, 2011, into abeyance until further notice. The policy expressed in the IM was developed by the 

Division of the National Landscape Conservation System and the Division of Decision Support, Planning and NEPA of the BLM. 

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rely on its inventory of LWCs in the development and revision of land use plans and when making 

subsequent project level-decisions. 

4.14 CULTURAL AND HISTORICAL RESOURCES 

4.14.1 Introduction 

Cultural resources on public lands, including archaeological sites and historic properties, are protected by 

various laws and regulations, for example the National Historic Preservation Act of 1966 (NHPA), 

Governing Regulations, and 36 CFR Part 800. The specific directives can be found in “Archaeology and 

Historic Preservation: Secretary of the Interior’s Standards and Guidelines” (Federal Register 1983). 

Laws and regulations concerning cultural resources stipulate that the proposed undertaking take into 

consideration the effects of the action to significant cultural resources. This requires that cultural 

resources within the proposed area of potential effect (APE) be identified and evaluated. Measures must 

be taken to mitigate or minimize any adverse effects to those historic properties included in, or eligible 

for, the National Register of Historic Places (NRHP). The Wyoming Cultural Records Office documents 

4,860 sites in the project area, as summarized in Section 3.14.3. Appendix J, Cultural Resources 

Management, describes how the BLM applies cultural laws and regulations to the inventory, 

classification, protection, and mitigation of cultural resources located on public lands. 

Many of the historic and prehistoric sites within the project area are located in eolian sand deposits with 

increased site density near playa lakes and springs. An extensive sand dune complex is located within the 

CD-C project area which has been designated Site 48CR5784. This area differs from other eolian sand 

dunes in the project area in that the eolian deposits are relatively stable and continuous for a nine-squaremile area. Very little development has occurred in this sand dune complex and the integrity of any 

cultural deposits has not been assessed. Soils mapping and a site-specific treatment plan were completed 

for the EIS. 

The BLM has designated a quarter-mile buffer surrounding the contributing segments of the historic trails 

and associated sites as highly sensitive. These eligible linear resources include the Overland and 

Cherokee Trails, the 1868 Union Pacific Railroad Grade, and the Lincoln Highway. All but the Cherokee 

Trail are located in the checkerboard land pattern; however, for the basis of this analysis, the calculations 

include both the public and private land. For management purposes, the BLM has established a two-mile 

analysis area around the trails for consideration of the elements of setting, defined as those elements of 

integrity of location, feeling, and association that contribute to the eligibility of the trails or associated 

sites. Although 2 miles is the standard distance for consideration of setting, it does not preclude the 

consideration of a larger area, depending on the circumstances. 

4.14.2 Management Objectives and Impact Significance Criteria 

The Rawlins RMP (BLM 2008a) prescribes the following management goals associated with cultural 

resources: 

1.	 Develop management plans for special areas or cultural resources (e.g., Aimee Eaton site, Powder 

Wash, Robbers Gulch, and Muddy Creek site complex) in areas of high risk for development or at 

high risk for adverse effects. 

2.	 Maintain setting for those contributing portions of historic properties where setting is an aspect of 

integrity by utilizing viewshed management tools (e.g., sacred sites, Lincoln Highway, Union 

Pacific Railroad [UPRR], and associated sites). 

3.	 Monitor the condition of historic properties that are known to be under threat from development or 

vandalism. 

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4.	 Identify cultural resources in the RMPPA by defining priority geographic areas for new field 

inventory, based on probability for unrecorded significant cultural resources. 

5.	 Develop a public outreach and education program to instill a conservation ethic in the public 

regarding cultural resources. 

6.	 Develop and maintain interpretation of cultural resources in areas of high public interest and access. 

7.	 Consult proactively with Native American tribes as appropriate to identify resource types or places 

that may be affected by BLM authorizations or actions. 

8.	 Seek opportunities for cooperation with tribal governments for management of cultural resources 

and public education. 

9.	 Maintain an inventory and evaluate historic transportation routes for contributing or noncontributing 

status (Appendix 5). 

The RMP also prescribes the following management goals for Historic Trails (Cherokee, Overland, 

Rawlins to Baggs, etc): 

1.	 Develop management plans for historic trails or segments of historic trails in areas of high risk for 

development or at high risk for adverse effects. 

2.	 Maintain setting for those contributing portions of historic trails where setting is an important aspect 

of integrity by utilizing viewshed management tools. 

3.	 Monitor the condition of contributing portions of historic trails that are known to be under threat 

from development. 

4.	 Maintain an inventory and evaluate trail segments and associated sites for contributing or 

noncontributing status. 

5.	 Provide educational opportunities and public outreach programs. 

6.	 Develop and maintain interpretation of historic trails in areas of high public interest and access. 

7.	 Manage historic trails and other resources for long-term heritage, recreational, and educational 

values. 

Impacts would be considered significant if management actions result in adverse effects to properties 

listed or determined eligible for listing on the NRHP or considered important to Native American groups 

as measured by: 

 Destruction or alteration of all or part of a property.
 

 Isolation of a cultural resource from, or alteration of, its surrounding environment. 

 Introduction of visual, audible, or atmospheric elements that are out of character with the property
 

or alter its setting. 

 Neglect and subsequent deterioration.
 

The criteria for evaluating cultural resource significance are described in the Code of Federal Regulations 

(36 CFR 60.4): 

“The quality of significance in American history, architecture, archaeology, engineering, and culture 

present in districts, sites, buildings, structures, and objects that possess integrity of location, design, 

setting, materials, workmanship, feeling, and association and: 

1.	 that are associated with events that have made a significant contribution to the broad patterns of our 

history; or 

2.	 that are associated with the lives of persons significant in our past; or 

3.	 that embody the distinctive characteristics of a type, period, or method of construction, or that 

represent the work of a master, or that possess high artistic values, or that represent a significant and 

distinguishable entity whose components may lack individual distinction; or 

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4. that have yielded, or may be likely to yield, information important in prehistory or history.” 

For cultural sites, both prehistoric and historic, significance is primarily judged either by the site’s ability 

or potential to yield information important in prehistory or history (Criterion D) or the site’s association 

with events that have made a significant contribution to the broad patterns of our history (Criterion A). 

Each site’s importance, however, is determined individually, so the existence of sites eligible under 

Criteria B or C must not be discounted. 

The BLM meets its responsibilities under Section 106 of the NHPA through implementation of a national 

Programmatic Agreement among the BLM, the Advisory Council on Historic Preservation (ACHP), the 

National Conference of State Historic Preservation Officers, and a state protocol with the Wyoming State 

Historic Preservation Office (SHPO) rather than by following the procedures set forth in the ACHP’s 

regulations (36 CFR Part 800). 

The preferred strategy of cultural resource management is avoidance of effect to those elements that 

contribute to the eligibility of a historic property. If this strategy cannot be implemented, mitigation of 

effects by project redesign, data recovery, project cancellation, or numerous other mitigation options 

should be implemented. 

4.14.3 Direct and Indirect impacts 

4.14.3.1 Proposed Action 

Eleven percent of the project area has been subject to Class III cultural resource inventory as a result of 

previous development. These inventories indicated a cultural site density of 0.04 sites per acre. Of the 

total sites within the project area, 23 percent on average could be expected to be eligible for the NRHP. 

These calculations assume that the area-wide site density is equal across the project area and that the 11 

percent of the area inventoried is a valid sample. With an estimated surface disturbance of 47,200 acres, 

the Proposed Action could affect an estimated 1,888 sites. Of these, 434 could be eligible for nomination 

to the NRHP. 

Gauging the effect of any impact depends on the level of information available for that particular property 

provided by inventory and/or testing data. In compliance with Section 106 of the NHPA, a Class III 

cultural resource inventory would be conducted for the proposed area of disturbance associated with each 

APD or other proposed project activity. The inventory would identify cultural resources either eligible or 

ineligible for inclusion on the NRHP and whether any of the NRHP-eligible sites would be adversely 

affected. The values that render a cultural resource eligible for the NRHP would dictate what type and 

kind of impacts are of concern. If a cultural resource is not listed on the NRHP or is determined by the 

BLM and SHPO as not eligible for listing on the NRHP, it is not a historic property for purposes of the 

NHPA and does not need to be considered under Section 106. 

For NRHP-eligible sites located in proposed disturbance areas, site avoidance is the preferred method of 

mitigation. However, when avoidance is not feasible, if any cultural resources listed on or eligible to the 

NRHP would be adversely affected by the Proposed Action, adverse effects would be appropriately 

mitigated as directed in Section 106. The Operator, in consultation with the BLM and the SHPO and with 

input from other interested parties per 36 CFR Part 800.6 and the Statewide Protocol Section VII, shall 

develop a mitigation plan designed to eliminate the adverse effects. These additional mitigation measures 

would be developed in accordance with BMPs and COAs outlined in Appendix C. Construction would 

not proceed until the terms of the mitigation plan were satisfied. Impacts to historic properties from 

projects occurring in the absence of a federal undertaking (federal authorization) would be beyond federal 

control. Data recovery (i.e., archaeological excavation), photo-documentation, additional archival 

research, or any other form of mitigation would be identified as part of the APD process and implemented 

prior to ground-disturbing activities associated with the Proposed Action. Implementation of appropriate 

mitigation measures would eliminate or minimize project-related adverse effects, and required additional 

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mitigation measures would meet or exceed these criteria. Data derived through mitigation could provide 

beneficial information on prehistoric and historic use in the CD-C project area, as well as contribute to the 

regional database for cultural resources. 

Direct impacts would primarily take the form of alteration or disturbance of previously unidentified sites. 

Physical disturbance of eligible sites could result from construction activities and associated operations 

and could adversely affect undiscovered archaeological sites. Cultural resource inventories may not locate 

all significant sites. Buried sites—in particular, burials—may be missed in the course of field 

investigations. If construction or other project personnel discover what may be human remains, funerary 

objects, or items of cultural patrimony on federal land, construction would cease within the vicinity of the 

discovery, and the Authorized Officer (AO) would be notified of the find. The AO would notify the 

appropriate County Sheriff and state medical examiner. Any discovered Native American human remains, 

funerary objects, or items of cultural patrimony found on federal land would be handled in accordance 

with the Native American Graves Repatriation Act. Non-Native American human remains would be 

handled in accordance with Wyoming law. Construction would not resume in the area of the discovery 

until the AO has issued a notice to proceed. 

Iincreased indirect impacts to archaeological sites could result from increased access within the project 

area, as well as increases in both surface activities and number of workers during construction associated 

with the Proposed Action. Potential indirect effects would include changes in erosion patterns due to 

construction, soil compaction, or vegetation removal; fugitive dust; off-road vehicle traffic associated 

with construction or maintenance activities; and increased vandalism, including illegal artifact collection, 

due to increased access. Where the setting of historic trails and associated sites contributes to NRHP 

eligibility, actions resulting in the introduction of visual elements that diminish the integrity of the 

property’s significant historic features must be mitigated. Best management practices to reduce visual 

impacts such as consolidation of facilities, low-profile tanks, and paint that blends with terrain would be 

implemented. 

4.14.3.2 Alternative A: 100-Percent Vertical Drilling 

Impacts to prehistoric and historic properties under Alternative A would be the greatest. With an 

estimated surface disturbance of 61,696 acres, an estimated 2,467 sites could be affected, of which 568 

could be eligible for nomination to the NRHP. Avoidance of significant cultural properties is the preferred 

management strategy. If avoidance is not possible, mitigation measures would be implemented on a caseby-case basis as outlined in Section 4.14.6. 

4.14.3.3 Alternative B: Enhanced Resource Protection 

Under Alternative B, with an estimated surface disturbance of 45,516 acres, an estimated 1,821 sites 

could be affected, of which 418 could be eligible for nomination to the NRHP. Avoidance of significant 

cultural properties is the preferred management strategy. If avoidance is not possible, mitigation measures 

would be implemented on a case-by-case basis as outlined in Section 4.14.6. 

4.14.3.4 Alternative C: Surface Disturbance Cap with High and Low Density Development 

Areas 

Under Alternative C, with an estimated surface disturbance of 42,955 acres, an estimated 1,718 sites 

could be affected, of which 395 could be eligible for nomination to the NRHP. Avoidance of significant 

cultural properties is the preferred management strategy. If avoidance is not possible, mitigation measures 

would be implemented on a case-by-case basis as outlined in Section 4.14.6. 

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4.14.3.5 Alternative D: Directional Drilling 

Under Alternative D, with an estimated surface disturbance of 36,449 acres, an estimated 1,458 sites 

could be affected, of which 335 could be eligible for nomination to the NRHP. Avoidance of significant 

cultural properties is the preferred management strategy. If avoidance is not possible, mitigation measures 

would be implemented on a case-by-case basis as outlined in Section 4.14.6. 

4.14.3.6 Alternative E: No Action 

Under Alternative E, because there would be no new natural gas development and no new surface 

disturbance, no sites would be affected and no cultural studies would be required as a result of this 

project. Impacts to historic properties from activities occurring in the absence of federal authorization 

would be beyond the oversight of the BLM. 

4.14.5 Impact Summary 

Impacts to cultural resources are assumed to be proportional to the amount of new surface disturbance for 

each alternative (i.e., increased disturbance would result in a proportionately increased potential for 

adverse impacts to prehistoric and historic resources). Impacts under Alternative A would be the greatest, 

with an estimated 2,467 sites that could be affected. Impacts would decrease proportionately for the 

Proposed Action (1,888 potentially affected sites), followed by Alternatives B (1,821 potentially affected 

sites), C (1,718 potentially affected sites), and D (1,458 potentially affected sites). No impacts would 

occur under Alternative E, No Action, because there would be no new natural gas development and no 

new surface disturbance. Avoidance and mitigation would remove the potential for significant impacts on 

public lands for all alternatives. 

4.14.6 Unavoidable Adverse Impacts and Additional Mitigation Measures 

Cultural resource inventories may not locate all significant sites—especially burials or other buried 

sites—resulting in unintentional destruction, alteration, or disturbance of artifacts or sites during 

construction and associated operations. Cultural resources may also become isolated from their 

surroundings if they are not discovered prior to project development, and/or the character or physical 

components of their settings may be altered by the introduction of visual, audible, or atmospheric 

elements. Appendix C describes mitigation measures for the inventory and protection of cultural sites 

discovered during project operations. No additional mitigation measures would reduce or eliminate 

impacts to undiscovered sites. 

Mitigation measures that would affect Historic Properties for which setting is an Aspect of Integrity, 

including visual, auditory, and atmospheric impacts, are described in Appendix C. The following 

additional mitigation measures would apply to all development activities under all alternatives that would 

affect those elements of a setting: 

 Begin reclamation at the time most optimal to regenerate the native species. 

 Replace native shrubs to decrease visibility. 

 Construct roads in minimally visible areas. 

 Relocate project or hide disturbance. 

 Use matting on rights-of-way during construction to minimize surface disturbance and visibility. 

 Allow no surface disturbance within a quarter-mile or the visual horizon, whichever is closer, of 

contributing segments of historic trails or trail-associated sites. 

 Limit trail crossings to existing disturbance corridors or non-contributing segments, unless 

otherwise determined by BLM in consultation with the SHPO. 

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An additional mitigation measure that may serve to minimize visual impacts to the setting of Historic 

Properties is the use of low-profile tanks. 

Direct impacts to other cultural resources would be further minimized by any mitigation measures that 

reduce the amount of surface disturbance using modified construction techniques. 

4.15 SOCIOECONOMICS 

This section provides an assessment of social and economic effects of the Proposed Action and 

Alternatives. 

4.15.1 Planning Documents and Regulations 

4.15.1.1 Rawlins RMP 

The Rawlins RMP (BLM 2008a) provides the following management goals and objectives for 

socioeconomics. 

Management Goals 

1.	 Provide opportunities to develop national energy resources on BLM-administered lands within the 

RMP project area. 

2.	 Provide opportunities to develop resources other than those related to energy (e.g., grazing, 

recreation, wildlife, fisheries, and tourism) on BLM-administered lands within the RMP project 

area.
 

3.	 Provide opportunities to sustain the cultural, social, and economic viability of local and regional 

communities by using decision review processes that include considerations of various potential 

impacts of BLM decisions, including: housing, employment, population, fiscal impacts, social 

services, cultural character, and municipal utilities. 

Management Objectives 

1.	 Work cooperatively with private and community groups and local government to provide for 

customary uses consistent with other resource objectives and to sustain or improve local, regional, 

and national economies. 

2.	 Maintain and promote the cultural, economic, ecological, and social health within the RMP project 

area. 

4.15.1.2 County Land Use Plans 

Carbon County 

The Carbon County Land Use Plan (CCLUP) (Carbon County Board of Commissioners and Carbon 

County Planning Commission 2010) was adopted in November of 2010. Although the CCLUP does not 

outline goals and objectives for natural resources development, it does specify recommended areas for oil 

and gas industry expansion and for an oil and gas industry processing and transportation corridor. The 

CD-C project area lies within the CCLUP’s recommended area for oil and gas exploration and 

production. 

The CCLUP contains the following goals, strategies and actions relative to energy development: 

Goal 1. Achieve a sustainable balance between energy development, agriculture, and the environment. 

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Strategies and Actions: 

Encourage a steady, paced development of the gas and oilfields. 

 Participate in comment periods of the federal environmental impact statement process.
 

 Attend meetings and hearings of the Industrial Siting Council.
 

Enhance the County government’s capacity to monitor, comment on, and influence state and federal 

decisions on energy development projects. 

 Conduct regular meetings between Board of County Commissioners, BLM, DEQ, USDA Forest 

Service, and other governmental bodies to share information about pending energy projects. 

 Participate in comment periods for environmental impact statements. 

Limit residential development-related impacts on resource extraction, irrigated lands, and agriculture in 

general. 

	 Create zoning incentives that encourage residential development in areas not suited for irrigation, 

agriculture, or resource extraction. 

Support mitigation of impacts created by energy industries where available science supports mitigation. 

 Maintain dialog with energy industries by regular meetings to keep communication current. 

 Identify issues that need mitigation and develop solutions for resolution with industry leaders. 

 If available science indicates a proposed energy project cannot mitigate its impacts, Carbon County 

should either not approve the project or else recommend that it be located in a more suitable 

location (Ibid, pps. 89–90). 

Sweetwater County 

Sweetwater County adopted the Sweetwater County Comprehensive Plan (SCCP) (Sweetwater County 

Board of Commissioners and Sweetwater County Planning Commission 2002) in the fall of 2002. The 

SCCP contains the following goals and objectives relevant to this assessment. 

Sensitive Areas and Resources 

Coordinate and cooperate with the appropriate federal, state, and local organizations, governments, and 

agencies to: 

 Identify and protect the county’s natural environment and resources. 

 Recognize and protect the county’s unique cultural, recreational, environmental, and historical 

resources. 

 Identify areas suitable/desirable for open space preservation. (These areas may include stream 

corridors, recreation areas, and wildlife habitat.) Explore alternative preservation strategies (Ibid, p. 

2.6). 

Planning Coordination/Cooperation with Other Entities 

 Support and participate in federal and state land-use planning activities. 

Natural Resources 

 Encourage and support environmentally responsible resource exploration/development within the 

region. This includes encouraging associated industries and businesses to locate within Sweetwater 

County communities. 

 Anticipate and plan for resource development impacts. Proactively address associated infrastructure, 

housing, and service needs. 

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 Encourage a balance between resource development and environmental protection. 

 Evaluate natural resource development proposals (and the associated land uses) for their effects on 

air, water, and environmental quality. 

 Encourage/support public land uses consistent with orderly development and efficient use of 

renewable and non-renewable resources. 

 Encourage the location of associated worker housing within existing communities where services 

are/can be provided.
 

 Work with resource managers to ensure adequate access to natural resources.
 

 Work with property owners and lessees to preserve adequate public access.
 

Public Lands and Resources 

 Encourage/support proactive county participation in relevant public land and resource planning and 

decision-making processes. 

 Encourage/support cooperative interaction between local, state, and federal agencies and private 

land owners. 

	 Promote agency awareness of county issues and interests. These include, but are not limited to: 

natural resource exploration and development, multiple-use land and resource management 

practices, agriculture/ranching and recreation, and adequate public access to and across public lands. 

	 Continue county support for resource-based industries including mineral exploration/development 

and ranching. 

	 Promote local (private) concerns and interests as an integral part of public land management 

decisions. County officials and plans will provide the foundation to address/protect to private 

interests related to public lands and resources.
 

	 Support, where appropriate, the transfer of suitable federal lands and resources to private interests. 

	 Encourage/support public land uses consistent with orderly development and efficient use of 

renewable and non-renewable resources.
 

 Prepare county policy positions for relevant federal and state land and resource issues. 

 Conduct county plan “consistency and coordination” reviews for/on all relevant public land 

management agency plans and decisions. 

 Develop/implement appropriate county/agency Memoranda of Understanding (MOUs) and 

agreements.
 

 Coordinate with public land management agencies to exchange resource and mapping 

information/expertise. 

4.15.1.3 Impact Significance Criteria 

The following criteria are used to assess the significance of the anticipated socioeconomic impacts of the 

Proposed Action and Alternatives and the No Action Alternative: 

	 An increase in a county’s or community’s resident and temporary populations that would 

substantially strain the ability of affected communities to provide housing and public services or 

otherwise adapt to growth-related social and economic changes 

	 An aggregate change in public revenue and expenditure flows likely to result in an inability on the 

part of affected units of government to maintain public services and facilities at acceptable or preestablished service levels 

	 Permanent displacement of residents or users of affected areas resulting from project-related 

changes in or conflicts with existing uses or ways of life 

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	 Disproportionately high and adverse environmental or human health impacts to an identified 

minority or low-income population, which appreciably exceed those to the general population in 

and around the project area 

4.15.2 Direct and Indirect Impacts 

Three key considerations shape this assessment: 

	 Ongoing Development in the CD-C project area― Oil and gas drilling, field development, and 

production activities have occurred within the project area for over 50 years and the pace of drilling 

has accelerated over the last decade. An average of 289 wells per year have been drilled in the 

project area over the last five years and at the beginning of 2011 there were an estimated 3,738 

producing wells within the project area. 

For all action alternatives, this assessment considers the effects of increased drilling, field 

development, and production activities. Thus, while the Proposed Action assumes annual drilling of 

an average of approximately 600 wells, the socioeconomic assessment considers the incremental 

socioeconomic impacts associated with the Proposed Action to be those associated with the drilling 

of roughly 300 additional new wells per year, along with subsequent completions and production. 

This approach acknowledges that the industrial and community infrastructure associated with the 

historic development of approximately 300 wells per year is already in place and local communities 

have addressed many of the socioeconomic effects associated with that pace of development. At the 

same time, the recent economic recession triggered a slowdown in pace of development that in turn 

resulted in an outmigration of non-resident oil and gas workers from the region. Consequently, the 

initiation of drilling at levels assumed for all action alternatives would result in a substantial influx 

of workers. Conversely, the No Action alternative would result in further outmigration of oil and 

gas workers from the region. 

	 Uncertainty—The socioeconomic assessment assumes a sustained, relatively high level of new 

well development over time. However, the actual pace of natural gas drilling has been and will 

continue to be variable and unpredictable because development decisions are dependent on a variety 

of factors including natural gas demand, pricing, regulatory approvals, rig and manpower 

availability, transmission pipeline capacity, weather, and the overall investment and development 

strategies of individual energy companies. For example, during the assessment period for this EIS, 

global energy demand and prices rose to historic levels and then declined precipitously. This decline 

was accompanied by a concurrent crisis affecting the availability of development capital, which 

hampered expansion and operations for some Operators and service companies. Although less 

affected than many other areas of the country, Carbon and Sweetwater counties each experienced 

economic slowdowns in the 2008 through 2010 period. 

To acknowledge this uncertainty, the assessment provides a discussion of the effects of higher and 

lower annual rates of drilling for certain social and economic conditions. 

	 Regional Context—Cumulative effects are analyzed in a separate section of this document, but for 

socioeconomics, cumulative influences must be considered in the assessment of impacts for the 

Proposed Action and alternatives. The natural gas reserves in the project area are part of a regional 

natural gas resource. Consequently, periods of expansion and decline in the project area would 

generally occur in the context of regional energy development expansion and decline in southwest 

Wyoming and indeed throughout much of the Rocky Mountain west. This means that extended 

periods of elevated demand for natural gas and resultant high gas sales prices would generate not 

only periods of accelerated activity in the project area but in other natural gas fields in Carbon, 

Sweetwater, and adjacent counties. Conversely, extended periods of lower natural gas demand 

would result in regional slowdowns in development activity. 

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4.15.2.1 Impacts Common to the Action Alternatives 

Natural gas development can have a variety of effects on social and economic conditions. These effects 

can be both beneficial and adverse and can include: 

	 Employment—effects on direct employment in the natural gas industry, induced employment in 

businesses that support the natural gas industry, and indirect effects on other sectors of the 

economy, including those sectors affected by changes in industry and employee spending and 

sectors that could be directly affected by development including outdoor recreation and ranching. 

Natural gas development can also affect community and regional economic diversity. 

	 Income—effects on income of direct, indirect, and induced businesses and their employees; on 

other sectors of the economy such as tourism, recreation, and ranching; and effects on landowners, 

mineral owners, and royalty interests. 

 Population—effects on resident and temporary populations in nearby communities. 

 Housing—demand for temporary and long-term housing.
 

 Infrastructure and services—demands on a variety of government and quasi-public and private 

facilities and services. 

 Fiscal conditions—changes in local and state tax and federal mineral royalty revenues and 

government expenditures. 

 Social conditions—effects on community stability and cohesion, quality of life, attitudes, opinions, 

lifestyles, and changes in crime and other social indicators. 

 Environmental Justice—beneficial or disproportionately high and adverse effects on minority and 

low-income populations. 

Each alternative considered in this EIS, including the No Action Alternative, has the potential to affect the 

social and economic conditions previously described in Section 3.15. All action alternatives would result 

in increased employment and income in certain sectors of the local economy and population growth with 

resultant increased demand for housing and community infrastructure and services. After all authorized 

wells are drilled, each alternative would result in decreased employment and income for certain sectors of 

the economy, and result in further outmigration of employees and households should the cessation of 

drilling coincide with a period of economic stability or decline in other regional economic activity. Each 

of the alternatives has the potential to affect other sectors of the economy, such as ranching and outdoor 

recreation, that are also closely linked to land use and access in the project area. Beneficial and adverse 

effects on community infrastructure, local government services, and community social conditions would 

also likely occur under all alternatives. 

Economic Effects 

Each action alternative would generate additional direct employment and income in the natural gas 

industry, indirect employment and income in businesses that support the natural gas industry, and induced 

effects on other sectors of the economy affected by changes in industry and employee spending. Each 

alternative would also affect other economic activities including outdoor recreation and ranching and 

could potentially affect regional economic diversity. 

Under the No Action Alternative, it is assumed that drilling and field-development employment would 

cease, resulting in a substantial decline in direct, indirect, and induced employment in the study area. 

Production-related employment would continue but diminish as production from existing wells declines 

and the wells eventually become uneconomical and production ceases. 

Under all action alternatives, employment and income associated with drilling and field development is 

assumed to occur over 15 years and then cease; production-related employment would continue at 

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substantially higher levels than under the No Action Alternative after Year 6, but again diminish as 

production decreases and previously drilled wells cease production. 

Induced and indirect employment associated with drilling, field-development, and production activities 

would parallel the advances and declines in direct employment for each alternative. 

Cyclical Economic Expansion and Contractions 

The economic expansion associated with each action alternative would likely be followed by a period of 

economic contraction.22 For the No Action Alternative, the contraction phase is assumed to begin upon 

the issuance of a ROD for the EIS and economic activity and employment would diminish as production 

decreases and eventually ceases. For all action alternatives, the current level of natural gas development 

would expand and extend drilling within the project area for approximately 15 years. The contraction 

phase would then begin as drilling and field-development employment ceases and production 

employment begins to decrease. 

The expansion phase would be characterized by substantial increases in direct employment and income in 

the natural gas industry and increases in indirect and induced employment and income. For the action 

alternatives, the 15-year drilling and field-development phase would be accompanied by increases in both 

temporary and long-term population as well as temporary and long-term housing demand, and demand for 

community infrastructure and local government services. For the No Action Alternative, these 

expansionary effects would not occur. To the contrary, No Action would precipitate further economic 

contraction. 

Federal, state, and local governments would receive additional tax and royalty revenues from all 

alternatives. Such revenues, particularly federal mineral royalties, would be substantially higher under the 

action alternatives when contrasted to the revenues associated with the No Action Alternative. 

The economic contraction phase would likely result in substantial reductions in employment, outmigration of workers and families, and reductions in demand for housing, community infrastructure, and 

local government services. The contraction phase would also be characterized by reductions in annual 

federal, state, and local government tax and royalty revenues. The severity of these effects would depend 

on other economic activities occurring at the time and the success of interim economic development 

initiatives. Under the No Action alternative, the contractions would follow the issuance of the ROD for 

this EIS. 

The foregoing discussion assumes the pace of development outlined for the Proposed Action and 

alternatives. Historically, natural gas development and expansion cycles have been more frequent and 

shorter in duration than the 15-year cycle assumed for all action alternatives in this EIS. 

Effects on Other Uses in the Project Area (Recreation and Ranching/Grazing) 

All alternatives have the potential to displace some other uses and users of the project area, temporarily in 

some instances and for longer periods in others. The current level of existing development and ongoing 

drilling and field-development activity has already altered the recreational setting in portions of the 

project area, displacing some recreation use (primarily hunting). The intensification of development 

would result in a more dense level of development in already-developed parts of the project area and 

perhaps introduce development in currently undeveloped areas. The effect of doubling the average annual 

level of drilling and field-development activity under the action alternatives would increase the potential 

for conflict with recreation activities and for displacement of recreation use of the area. Over time, as 

development and production activities cease and reclamation occurs, recreation users may return to the 

22 This characterization of effects is a function of the assumption of the steady pace of new well development. In fact some variability 

would be expected over time. Such variability would likely temper both the expansions and contractions described here. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 4-147 
CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—SOCIOECONOMICS
 

project area. Shifts in the geographic distribution of hunting and other recreation activity could have 

corresponding economic implications as well. 

Grazing patterns and practices in the project area have already been affected by natural gas development 

activity. The boundaries of some grazing allotments extend beyond the project area, but the portions of 

these allotments in some areas adjacent to the project area are also affected by natural gas development. 

The high level of development activity, disturbance, infestation of invasive plant species and resultant 

reductions in available forage have resulted in reductions in use of certain allotments and require grazing 

permittees to more actively monitor and more frequently move livestock, resulting in higher labor and 

fuel costs and reductions in livestock weight gain. These effects—together with damage to fences, cattle 

guards, and other grazing improvements; increased livestock mortality from vehicle/livestock collisions; 

an extended period of drought; volatile livestock sales prices; difficulty obtaining capital; high fuel costs; 

and labor shortages—have resulted in higher cost, lower production, and reduced profitability for grazing 

permittees and temporarily displaced some permittees from allotments within the project area. Some 

grazing permittees interviewed for this assessment tied these effects to actual or anticipated reductions in 

herd size, complete sell-off of herds, and serious consideration of relinquishing their BLM grazing leases. 

Permanent displacement of grazing permittees along with a substantial reduction in overall levels of 

grazing use could trigger the significance threshold established for this assessment. 

Under the No Action Alternative, the adverse effects on grazing permittees associated with high levels of 

drilling and field-development activity and traffic would diminish as drilling and field-development and 

associated traffic ceases, and temporary disturbances are reclaimed. Under all of the action alternatives, 

the levels of drilling and field-development and associated traffic could potentially double over recent 

levels and the amount of temporary and long-term disturbance would increase substantially, likely 

resulting in displacement of grazing operators from portions of allotments that are undergoing intensive 

development. Adverse effects on portions of grazing allotments, coupled with the aforementioned other 

factors (drought, high labor costs, volatile livestock sales prices, and scarcity of operating capital) could 

have detrimental effects on the economic viability of some affected ranches. 

Effects on Environmental Amenity Values 

As noted in Section 3.15.7.1, environmental amenities including air and water quality, wildlife and 

wildlife habitat, scenic vistas, cultural and historical features, and areas that provide opportunities for 

solitude are highly valued by many local residents and non-residents alike. These amenities add to the 

quality of life for residents, provide value by promoting local tourism and recreation, and are some of the 

factors that can attract new residents and businesses to an area. Many people value these amenities for 

their very existence and desire their continued availability for future generations. 

Much of the project area has already been affected by development, adversely affecting some outdoor 

amenities including wildlife and wildlife habitat, scenic vistas, and areas that provide opportunities for 

solitude. All alternatives would continue to affect these amenities, although the No Action Alternative 

would result in no incremental effect. The action alternatives would intensify development in many 

currently developed areas of the project area and perhaps result in development in currently undeveloped 

areas. 

In addition to the effects of development, disturbance, and activity on environmental amenities, the 

proliferation of litter along roads and increases in poaching that have accompanied development activity 

adversely affect scenic and wildlife amenities. These effects would continue under all alternatives but 

would likely intensify under the action alternatives given the increase in activity and extended duration of 

the drilling and field-development phase. 

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Economic Diversity 

Energy development has the potential to enhance economic diversity in rural communities by expanding 

commercial and community infrastructure and by providing funding which can be used for economic 

development, community revitalization, and tourism promotion efforts. Energy development also has the 

potential to limit economic diversity in rural communities by raising housing costs and limiting housing 

availability, contributing to workforce shortages, and adversely affecting environmental amenities. 

Potential dampening effects of natural gas development in the project area on the growth and maintenance 

of economic diversity in certain communities within the study area would diminish sooner under the No 

Action Alternative as labor competition and high housing costs decline, the perceived effects on amenity 

values diminish as drilling and field-development cease, and long-term reclamation proceeds. Potential 

dampening effects on economic diversity would intensify under all action alternatives as the pace and 

duration of drilling would increase substantially and housing demand and cost and labor shortages would 

likely increase. The potential dampening effects on economic diversity should be viewed in the context of 

the cumulative development within the study area as high levels of drilling in the project area would 

likely be accompanied by high levels of drilling elsewhere in the study area. Potential economic diversityenhancing effects could ultimately be associated with all action alternatives as well as with cumulative 

development. Energy development in the region has expanded the inventory of housing, tourism and 

recreation infrastructure (motels and restaurants), other commercial infrastructure, and increased the 

resident workforce in communities in the study area, all of which would be resources for economic 

development as natural gas development subsides. 

4.15.2.2 Proposed Action 

Oil and natural gas exploration and production have been important but volatile elements of the Carbon 

and Sweetwater County economies for well over 30 years. According to the Wyoming Oil and Gas 

Conservation Commission (WOGCC), there were 1,791 producing wells in Carbon County in 2010, with 

another 3,234 producing wells in Sweetwater County, although natural gas production in the two counties 

declined by 4 percent in 2010. 

Up to 8,950 additional wells would be drilled in the project area over the course of 15 years under the 

Proposed Action; an average of almost 600 new wells drilled annually. Information provided by the 

Operators indicates that a range of 213 to 738 new wells per year (Figure 4.15-1) would be drilled. The 

pace and timing of natural gas development are two key variables affecting socioeconomic conditions in 

communities near development. The actual pace and timing of development in the project area would be 

dependent on a variety of factors including natural gas demand, pricing, regulatory approvals, rig and 

manpower availability, weather, and corporate strategies. Given the cyclical nature of natural gas 

development and the regional nature of the natural gas development industry discussed in Section 

4.15.2.1, the assessment also considers the socioeconomic effects of surges and declines in development 

that might result in higher or lower levels of drilling than those contemplated by this assessment. 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—SOCIOECONOMICS
 

Figure 4.15-1. Number of new wells drilled in the project area, Proposed Action 

Source: CD-C Operators. 

Implementation of the proposed drilling program would result in consistently increasing production over 

the first 13 years of drilling, with projected annual production peaking at more than 670 MMcf and 9.4 

million bbls of liquid condensates. Production would then begin an extended period of decline (see 

Figure 4.15-2). 

0 

100 

200 

300 

400 

500 

600 

700 

800 

Yr 0 Yr 5 Yr 10 Yr 15 Yr 20 Yr 25 Yr 30 Yr 35 

Annual Gas Production (Bcf) 

Figure 4.15-2. Estimated incremental annual gas production, Proposed Action 

Source: BLM RMG estimates, BCLLC/SDLLC calculations. 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—SOCIOECONOMICS
 

Estimated total production for the Proposed Action over the life of the field is 12.02 trillion cubic feet 

(Tcf) of gas and 167.3 million bbls of liquid condensates. 

Employment 

A key driver of the socioeconomic impacts of the Proposed Action and alternatives is the estimated direct 

employment associated with the proposed natural gas development, extending from pre-development 

approval and permitting through drilling, completion, production, and reclamation. The direct 

development and operations jobs would in turn support additional indirect and induced jobs in the local 

economies, all of which would create demands on the local labor force, promote economic migration and 

population growth, increase demands on housing and public facilities and services, and affect local social 

conditions. 

The labor-intensive drilling and completion phase for new wells is of initial concern for assessing shortterm effects on migration, population, housing demand, and public facilities and services. Over time, the 

level of Proposed Action-related field operations and production employment would rise due to the need 

to service additional wells and haul increased volumes of produced water and condensate. 

Project-related direct employment estimates were developed based on information obtained from the 

Operators, the U.S. Bureau of Labor Statistics, U.S. Bureau of Economic Analysis, Wyoming Department 

of Employment, and other sources. Projected direct employment estimates were then used as the primary 

input into the REMI23 economic-demographic model, calibrated for a six-county region of southwest 

Wyoming, which in turn yields projections of the total employment, income, population, and other 

economic and demographic changes over time. 

It is important to note that the employment projections described in this section are based on current 

natural gas development and production employment experience in the CD-C project area. In recent 

years, the Operators have been successful in refining development and production technologies and 

processes, which has reduced labor force requirements on a per well basis. It is reasonable to assume that 

further technology and process refinements will further reduce workforce requirements, particularly in the 

later years of this period used for this assessment. 

Estimated Direct Jobs 

Information supplied by the Operators indicates that development of a typical well in the project area, 

from access road and pad construction through drilling, completion, installation of surface production 

facilities and gathering lines and interim reclamation, requires approximately 30 days. Direct onsite 

employment at an individual well site varies over time, ranging from a single field biologist doing predevelopment site clearance to 25 or more drilling and well-service employees during actual drilling and 

completion operations. Some development activities and events are of relatively short duration (a matter 

of hours); others continue for days on a round-the-clock basis. Interim reclamation would also occur at 

each site, employing a small number of workers for several days. Additionally, project engineers and 

managers, state and federal regulatory and resource management staff, and others occasionally visit an 

23 The Economic Profile System – Human Dimensions Tool (EPS-HDT), created by Headwaters Economics, Inc. and supported by 

the U.S. Bureau of Land Management, is a valuable tool for characterizing and describing historic economic and demographic 

trends in a region. It was also used to inform this assessment. EPS–HDT does not offer a forecasting or projection capability to 

assess changes in employment and income stemming from new economic stimulus. Many assessments rely on economic inputoutput (I-O) models to estimate the indirect and induced effects of natural resource development initiatives. The use of such I-O 

models has received criticism. Such criticism is one factor that led to the use of the REMI model in this assessment. 

 REMI is a dynamic, econometric economic and demographic model developed by Regional Economic Models, Inc. that has 

gained broad professional recognition and acceptance. Versions of the core model are calibrated for specific geographic regions. 

The specific application of the REMI to this project was completed by Sammons/Dutton LLC (SDLLC) and Blankenship 

Consulting, LLC (BCLLC). The REMI model is used because its capabilities address many of the more common criticisms 

associated with the use of economic input-output (I-O) models, including the static nature of the economic relationships and lack 

of a demographic component. 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—SOCIOECONOMICS
 

individual well site, but are not included in the Operator’s summary of onsite employees. Allowances for 

these workers were captured in adjustments for off-site direct employees and estimated induced 

employment. 

The Operators provided information regarding the timing/phasing of development activities, duration of 

activities, and approximate numbers of employees, including both company and contractor employees, for 

a typical well in the project area. Separate development profiles were provided for single-bore vertical 

wells and for multiple-bore directional wells from a single location. These profiles are the basis for 

estimating direct onsite employment during field development, based on the concept of work teams or 

crews, with a work team or crew responsible for each of the major development activities. Individual 

members of a crew may work together or independently, may be company employees or contractors, and 

may complete some of their work off-site. Given the varying durations of the key activities, it is estimated 

that completion of an average of almost 600 new wells per year under the Proposed Action could involve 

as many as 100 separate work crews within the field on any given day, of which approximately 25 would 

be drilling crews directly associated with operating rigs. Table 4.15-1 summarizes the estimated numbers 

of crews and average crew size associated with the Proposed Action. 

Table 4.15-1. Overview of direct onsite labor effort to implement the Proposed Action, CD-C project 1 area

Activity Approximate 

Number of Crews Workers / Crew Typical Activity Duration 

Pre-approval / permitting 6 6 3 days 

Location construction 10 5 6 / 14 days 

(single well / multi-well) 2 

Rig mobilization / de-mobilization 10 11 3 / 5 days 

(single well / multi-well)2 

Drilling 2524 18 10 / 42 days 

(single well / multi-well) 2 

Completion 17 11 5 / 8 days 

(single well / multi-well)2 

Well service 7 22 3 days 

Tank battery setup 9 6 4 days 

Gas-gathering system 2 15 1 day 

Electrical system 3 8 1 / 2 days 

1

 Assumes 60 percent are single-bore vertical wells and 40 percent are directional bores with an average of four completed bores 

per multi-well location. 2

 Average per well bore. 

Sources: CD-C Operators, BCLLC, and SDLLC. 

Factors including the numerous tasks involved in drilling, completing, and bringing a well into 

production; the specialized nature of crews involved in completing those tasks; the different number of 

individuals associated with the various crews and varying durations for distinct tasks; and the fact that the 

work schedules of different crews vary (some 5-day/40-hour weeks, some round-the-clock for extended 

periods of time) results in fluctuating levels of onsite employment within the project area over time. Over 

a typical eight-week period, onsite employment within the project area would range from just over 500 

jobs to more than 970 jobs, with an average of approximately 765 jobs. 

The round-the-clock drilling and sequential nature of some activities results in a considerable level of 

activity on weekends and requires additional employees to sustain work crews during scheduled times off, 

24 The Operators have estimated that between 20 and 40 rigs could be on location within the project area at any one time. Some 

rigs contracted to major Operators would be working on a continuous year-round basis, while others contracted to small 

independent Operators would drill one or two wells in any one year. An average of 25 rigs was used for this assessment. 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—SOCIOECONOMICS 

illness, injury, or labor market inefficiencies. A 15-percent allowance above the average onsite 

employment is used for this analysis, raising the total direct onsite jobs supported by the Proposed Action 

to 881 employees. The breakdown of those jobs by major activity is presented in Table 4.15-2 below. 

Table 4.15-2.	 Average onsite and total direct employment during the development phase, 

Proposed Action 

Industry/Activity Onsite Direct Total Direct 

Drilling / rig services 443 532 

Completion / field services 311 373 

Construction 92 110 

Engineering / environmental services 35 42

 Total 881 1,057 

Source: BCLLC and SDLLC 

The direct workforce estimates for the development phase include one further adjustment; that being an 

allowance for administrative, management, maintenance, clerical, and other support employees working 

locally for the company and contractors to support the workers actually working onsite. An example of 

such direct-support jobs would be the mechanics based in Rock Springs who maintain and service the 

drilling rigs and gas-field service trucks. This analysis includes a 20-percent allowance for such jobs, 

based on data from the U.S. Bureau of Labor Statistics and economic censuses of industry. The 

adjustments for administrative and support personnel raise the total direct employment associated with the 

Proposed Action to 1,057 (Table 4.15-2). 

Direct onsite employment was also estimated in conjunction with ongoing production and field 

operations. The primary activities associated with operations would be the ongoing monitoring, 

maintenance, and servicing of the wells, occasional well workovers, and the hauling of produced water 

and condensate.25 The numbers of jobs in all three categories would climb over time as the cumulative 

number of producing wells increases. The annual numbers of well service employees are estimated from 

information provided by the Operators and the numbers of transportation workers are a function of the 

estimated water and oil condensate production. Estimates of the number of production and transportation 

workers account for the diminishing levels of production from the existing wells over time. As with the 

development employment, the estimates of operations employment include allowances to account for 7­

day-per-week staffing and for management and support employees. Estimated direct employment for 

operations derived using these assumptions climbs steadily over time, eventually peaking at 2,494 

employees in Year 13 of the project (see Figure 4.15-3). The peak coincides with a year of high new 

development (671 new wells) combined with high levels of water and condensate production. 

25 Some producers may develop piping systems to handle produced water. Such systems would reduce the number of employees 

required. However, the extent of such systems is currently unknown. Consequently, the current analysis assumes an all truck haul 

cenario in order to portray a “worst case” scenario with respect to both transportation and socioeconomics. 

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0 

500 

1,000 

1,500 

2,000 

2,500 

3,000 

Yr 1 Yr 6 Yr 11 Yr 16 Yr 21 

Direct Jobs 

Direct Off-site 

Direct On-site 

Figure 4.15-3. Direct employment, onsite and off-site, Proposed Action 

The current assessment addresses the incremental increase in employment due to the Proposed Action. 

Such increases would be above and beyond the employment already working in the project area due to the 

ongoing drilling and production activity by the CD-C Operators, which is estimated at about 522 at 

present. The resulting incremental direct employment estimates, shown in Table 4.15-3 and Figure 4.15-

4, would increase to a peak of 1,600 total direct jobs in Year 13. Direct employment would decline 

sharply following the completion of new well development, shedding nearly 1,200 total direct jobs by 

Year 20. 

Table 4.15-3	 Incremental direct employment during field operations and 

production, Proposed Action1 

Year Total Direct Incremental Direct Due to the PA 

Year 5 1,838 1,128 

Year 10 2,413 1,585 

Year 15 1,602 666 

Year 20 784 475 

Year 25 634 431 

1

 Incremental is relative to the estimated direct CD-C-related employment in 2007. 

Source: SDLLC and BCLLC. 

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0 

500 

1,000 

1,500 

2,000 

Yr 1 Yr 6 Yr 11 Yr 16 Yr 21 

Direct Jobs 

Figure 4.15-4. Incremental direct employment, Proposed Action 

Estimated total direct employment over time, by major industrial sector, is the primary input driving the 

economic and demographic forecasts associated with the Proposed Action. Features in the REMI model 

were used to increase the likelihood that much of the growth in labor demand from the Proposed Action 

would be satisfied by non-residents who would work in the region on a temporary basis while 

maintaining their permanent residence elsewhere, and also that migrating workers would be more 

predominantly male than the general population. Both of these characteristics have been observed in the 

local labor force in conjunction with recent and ongoing energy resource development in southwest 

Wyoming. 

In addition to the employment associated with drilling, field development, and production, Proposed 

Action-related employment would occur in conjunction with the construction of ancillary facilities 

including up to ten field compression facilities, a central pipeline compression facility, one or two central 

processing/stabilization plants, and up to 45 miles of high-pressure pipeline. The timing, location, and 

ultimate configuration of these facilities are not currently known, but their development would result in 

additional short-term construction and secondary employment during the period in which they were 

constructed. Most of these facilities would be constructed over a matter of months using a mix of local 

and non-local construction workers. The central processing/ stabilization plants could require a year or 

more to construct, with a workforce ranging to several hundred workers at peak. 

Effects on Total Employment 

Economic activity associated with the Proposed Action would result in additional economic growth in the 

two-county region. The incremental employment growth would increase over time as production 

increases the demands for operations and water and condensate transportation. 

Projected employment gains of 890 jobs in the region would result from the Proposed Action in the first 

full year of expanded drilling. The total includes an estimated 428 direct jobs and 432 additional indirect 

and induced jobs supported by the increased economic stimulus associated with new well development, 

purchases by the Operators, suppliers and vendors, the consumer purchases of employees, and increased 

expenditures by local public entities. The net employment increment associated with the increased 

development activity in Sweetwater and Carbon counties would climb to 3,951 jobs in Year 13 (Figure 

4.15-5). That total includes the 1,865 direct jobs and 2,086 indirect and induced jobs supported by the 

Proposed Action. Over the 15-year period of project development, each direct job is estimated to support 

approximately 1.14 additional induced and indirect jobs. 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—SOCIOECONOMICS
 

-

1,000 

2,000 

3,000 

4,000 

5,000 

Yr 1 Yr 5 Yr 9 Yr 13 Yr 17 

Indirect & Induced Incremental Proposed Action 

Figure 4.15-5. Direct, indirect, and induced employment effects from the Proposed Action in 

Sweetwater and Carbon Counties 

All sectors of the local economies would be expected to see job gains as a result of the Proposed Action. 

Beyond the direct impacts in mining (including the oil and gas industry) and transportation, the largest 

gains in private sector jobs would occur in retail and wholesale trade, construction, and accommodations 

and food service. Local government employment, including public education, would also increase given 

implementation of the Proposed Action. The distribution of the net job gains in the peak year, by selected 

major industrial sector, is presented in Table 4.15-4. 

Table 4.15-4. Incremental numbers of jobs by industrial sector, Year 13 

Industrial Sector Jobs Share 

Mining (including oil and gas drilling, production and services) 1,699 43% 

Construction 619 16% 

Retail & Wholesale Trade 348 9% 

Accommodations and Food Services 238 6% 

Local Government 198 5% 

Real Estate, Rental, Leasing 173 4% 

Transportation and Warehousing 164 4% 

Health Care and Social Assistance 168 4% 

Administrative and Waste Services 98 3% 

Professional Technical Services 77 2% 

State Government 29 <1% 

All other combined 140 4%

 Total 3,951* 100.0% 

* Other includes: manufacturing, information services, other services, management of other companies, educational 

services, forestry, and fisheries. 

** The total includes projected indirect and induced jobs in Uinta, Lincoln, Fremont, and Sublette counties. 

The majority of the new jobs, including not only direct jobs but also indirect and induced jobs, would be 

based in Sweetwater County, although substantial job gains are projected to occur in Carbon County. Net 

gains in Sweetwater County are projected to be nearly 600 jobs in the first year of development, 

increasing to more than 2,800 jobs at the peak. The corresponding range of job gains in Carbon County is 

from 197 jobs in Year 1 to 966 jobs at the peak (Figure 4.15-6). New well development under the 

Proposed Action is also projected to result in up to 170 incremental indirect and induced jobs elsewhere 

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in southwestern Wyoming due to increases in local income and spending associated with commuters who 

live in one county and work in either Sweetwater or Carbon counties. 

(1,000) 

(500) 

-

500 

1,000 

1,500 

2,000 

2,500 

3,000 

Yr 1 Yr 3 Yr 5 Yr 7 Yr 9 Yr 11 Yr 13 Yr 15 Yr 17 Yr 19 

Sweetwater Carbon 

Figure 4.15-6. Total employment effects in Sweetwater and Carbon Counties from the 

Proposed Action 

Completion of field-development operations would trigger substantial reductions in employment. Net 

reductions of more than 4,300 jobs (approximately 3,100 in Sweetwater County) are projected in the two 

counties within two years of field development completion. Further declines would be expected over the 

following three years such that the net change in total employment, as compared to the outset of the 

project, would become negative even though more than 475 direct employees would be involved in 

continuing production and transportation. This seeming paradoxical result would occur because of the 

loss of drilling and development jobs previously associated with ongoing development activity in the CDC project area that would be sustained by the approval of the Proposed Action. 

At the peak, the Proposed Action would increase the combined total local employment in Sweetwater and 

Carbon counties by about 9 percent as compared to total current (2009) employment. The net increase in 

local employment attributable to the Proposed Action would also be comparable to the increase in 

combined employment anticipated from all other economic activity in Sweetwater and Carbon counties. 

Year-to-year variability in the pace of drilling would likely result in some corresponding fluctuations in 

the number of drilling and field-development jobs; higher rates translating into more employees and lower 

rates of drilling requiring fewer employees. Levels of off-site direct employment would likely be slightly 

less sensitive to fluctuations in drilling employment, but sustained differences in the annual number of 

wells drilled would eventually be accompanied by commensurate changes in off-site employment. 

Differences in the annual rate of drilling and development would translate into slight differences in the 

number of incremental operations and production employees hired, but such employment tends to be 

more responsive to the long-term levels of production than to current drilling rates. 

Other Economic Effects 

At the time of the original assessment (2007), labor-market conditions in the project area were tight due to 

past and ongoing energy and mineral resource development. Unemployment rates were low, labor-force 

participation among residents was high, and temporary, non-resident workers filled many jobs. Estimates 

generated by the REMI model suggested that as many as one in five jobs added prior to the recession had 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—SOCIOECONOMICS
 

been filled by temporary or commuting non-resident workers. As the economic recession persisted, 

triggering layoffs, labor-market conditions eased, increasing worker availability and out-migration of 

some non-resident workers. The higher rate of development associated with the Proposed Action would 

likely result in a return to pre-recession conditions, including lower unemployment as available local 

labor is absorbed and an influx of workers, many of whom would be single-status. Labor-market 

conditions would again change once project development is completed and labor demand weakened 

relative to available supply. Local unemployment would increase, labor-force participation would decline, 

and labor-force out-migration would likely occur. 

Per-Capita Personal Income 

Total and average per-capita personal income would increase under the Proposed Action. Total personal 

income would rise due to increases in the number of jobs, particularly in the relatively higher-paying 

energy-sector jobs. More energy-sector related jobs would contribute to rising per-capita incomes, which 

would also receive a boost from the upward pressure on all wages and salaries from the tight labor 

markets. Some of the gains in personal income would likely be offset by higher consumer prices. The 

positive project-related effects on income would moderate and eventually diminish, particularly following 

the completion of the well-development phase. 

Population Growth 

Implementation of the Proposed Action would provide a long-term economic stimulus to the local 

economies of Sweetwater and Carbon counties. Local labor availability to fill the jobs supported by the 

economic expansion is limited due to recent and ongoing economic expansions in the region. Past 

expansion also triggered substantial labor immigration to the area. Future expansion with the Proposed 

Action would trigger additional migration and population growth for the region. 

Under the Proposed Action, substantial net labor migration would occur during the first several years of 

implementation, peaking at over 600 in Year 2. Projected annual net migration attributable to the 

Proposed Action would fluctuate in response to the variation in the pace of drilling, averaging about 275 

people per year through the completion of development. Substantial net out-migration of more than 800 

residents per year would occur for several years after the cessation of drilling (Figure 4.15-7). The rate of 

net out-migration would be less pronounced than the initial immigration due to the continuing operations 

and transportation employment associated with the Proposed Action. 

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-4000 

-3000 

-2000 

-1000 

0 

1000 

2000 

3000 

Yr 0 Yr 2 Yr 4 Yr 6 Yr 8 Yr 10 Yr 12 Yr 14 Yr 16 Yr 18 Yr 20

Net Annual Migration ( x 1,000) 

Figure 4.15-7. Projected net migration into the study area 

Driven by migration, population growth due to the Proposed Action is projected to increase over time to 

almost 4,936 residents in Year 14. Approximately 3,100 additional residents are projected to reside in 

Sweetwater County, with 1,050 additional residents in Carbon County (Table 4.15-5 and Figure 4.15-8). 

The majority of the project-related incremental population in Sweetwater County would be expected to 

reside in Rock Springs and Wamsutter. In Carbon County, most of the incremental population would be 

anticipated to live in Rawlins and Baggs/LSRV. The net increase in population is comparable to the net 

increase in employment, reflecting a combination of a high level of single-status workers, two-worker 

households, and workers holding multiple jobs among the immigrating households, and an increasing 

number of temporary non-resident and commuting workers. 

Table 4.15-5. Summary of incremental population impacts from the Proposed Action 

Year 1 Year 5 Year 10 Year 15 Year 20 

Sweetwater County 236 1,349 2,399 2,990 1,033 

Carbon County 69 410 793 1,028 311 

Combined Increment 305 1,759 3,192 4,018 1,344 

Source: SDLLC and BCLLC, using the REMI model. 

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-

500 

1,000 

1,500 

2,000 

2,500 

3,000 

3,500 

Yr 1 Yr 3 Yr 5 Yr 7 Yr 9 Yr 11 Yr 13 Yr 15 Yr 17 Yr 19 

Sweetwater Carbon 

Figure 4.15-8. Forecast population increments due to the Proposed Action 

The effects of the Proposed Action would contribute to growth during the development period, with 

population peaking in about Year 14 or 15 and then declining in the wake of the economic contractions 

associated with the completion of drilling. At the peak, the incremental population impacts associated 

with the Proposed Action would represent about 8 percent of the combined 2010 resident populations of 

Sweetwater and Carbon counties. 

The estimated population impacts presented above may overstate the actual change in resident population 

by the extent to which jobs are filled by unaccompanied temporary non-resident and commuting workers. 

While these workers would place demands on local facilities and services, increase market demand for 

private-sector businesses, and generate public-sector revenues, they have fewer indirect demands on 

facilities, services, and conventional housing than do migrating households. 

Results of the model indicate that the number of non-resident workers would increase over time to meet 

the labor demands associated with production and transportation operations. Following the completion of 

new well development, the number of non-resident workers would decline substantially. 

Short-term surges in temporary population would accompany the construction of the ancillary facilities 

described in the preceding employment section. The operations workforce associated with these facilities 

would be relatively small and result in small long-term changes in population within the study area. 

Population Distribution in Sweetwater and Carbon Counties 

The incremental population growth and additional non-local workers residing in the region would create 

demands on housing, private-sector businesses, and public facilities and services, with the incidence of 

demands on various providers being determined largely on the residency patterns of the new residents and 

workers. In turn, three important factors affect residency patterns: housing availability, the base of 

operations/location of the jobs, and proximity to community facilities and services. Among those factors, 

job location and housing availability, including temporary living facilities, tend to be more influential for 

the temporary workers. Housing availability and proximity to community facilities and services are 

typically more influential for those production and transportation workers who establish long-term 

residence in the area, and even moreso for those filling the indirect and induced jobs supported by the 

Proposed Action. 

Residency assumptions for the temporary and permanent populations were established considering the 

size of communities, their distances from the project area, informed judgment regarding housing 

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availability (including the potential development of construction-worker housing in the area) and historic 

residency patterns of natural gas workers. Applying the assumed residency patterns to the incremental 

project-related population shows an increasing population over time, peaking at more than 2,100 residents 

and 128 temporary workers in Rock Springs in Year 15, with a corresponding peak in excess of 758 

residents and 52 temporary workers in Rawlins in that year (Table 4.15-6). The peak influx of temporary 

workers actually happens several years earlier. It is important to note that these estimates are in addition 

to the population associated with ongoing development and production operations in the project area. 

Table 4.15-6. Incremental resident population and non-resident workers by community 

Year 1 Year 5 Year 10 Year 15 Year 20 

Sweetwater County 

Rock Springs 

Long-term 25 646 1,310 2,136 644 

Temporary 81 217 304 128 -

Total 106 863 1,614 2,264 644 

Wamsutter 

Long-term 3 81 164 267 81 

Temporary 122 325 457 192 -

Total 125 406 621 459 81 

Green River 

Long-term 2 65 131 214 64 

Temporary - - - - -

Total 2 65 131 214 64 

Other & Unincorporated 

Long-term 1 15 33 53 16 

Temporary - - - - -

Total 1 15 33 53 16 

County Total 

Long-term 31 807 1,638 2,670 805 

Temporary 203 542 761 320 -

Total 234 1,349 2,399 2,990 805 

Carbon County 

Rawlins 

Long-term 14 220 482 758 203 

Temporary 33 88 124 52 -

Total 47 308 606 810 203 

Baggs/LSRV 

Long-term 3 50 109 171 46 

Temporary 8 20 29 12 -

Total 11 70 138 183 46 

Unincorporated, including 

man camps and Other 

Long-term 1 5 12 19 5 

Temporary 10 27 37 16 -

Total 11 32 49 35 5 

County total 

Long-term 18 275 603 948 254 

Temporary 51 135 190 80 0 

Total 69 410 793 1,028 254 

Total assigned 

"population" 

Long-term 49 1,082 2,241 3,618 1,059 

Temporary 254 677 951 400 -

Total 303 1,759 3,192 4,018 1,059 

Source: SDLLC and BCLLC, using the REMI model. 

The most notable effect on local population would be expected to occur in Wamsutter. The town is 

located at the I-80 interchange that serves as the major access point into the project area. BP has 

established a field operations center in Wamsutter and a number of oil and gas service firms have 

established offices and yards in the town. Furthermore, some new permanent housing has been developed 

in Wamsutter, and temporary living facilities have been located in Wamsutter during past periods of high 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—SOCIOECONOMICS
 

drilling activity. An initial impact of 125 residents and non-local workers is projected in Year 1, 

increasing to over 400 within the next two years. Provided adequate housing is available, the net 

population growth increment is projected to increase to over 600 residents and temporary workers in Year 

10. 

In summary, implementation of the Proposed Action would result in substantial incremental employment 

and population growth in Sweetwater and Carbon counties, with the net increments increasing over time 

until peaking in Year 14 of the project. Thereafter the impacts would diminish although ongoing 

production would sustain ongoing operations and transportation employment for more than 40 years. The 

peak employment impacts are estimated at 3,951 jobs, including 1,863 direct jobs and 2,088 indirect and 

induced jobs. A peak population impact of nearly 3,700 permanent residents is projected. At the peak, the 

incremental population attributable to the Proposed Action would represent about 8 percent of the total 

population of the respective counties. Following the completion of new well development, the 

incremental employment and population impacts would decline to levels sustained by the ongoing 

production and transportation. At that time, substantial out-migration of Proposed Action-related 

population would be anticipated to occur, in the absence of other major economic activities. 

Fluctuations in annual drilling rates would result in substantial increases or decreases in temporary 

workers. Corresponding effects on indirect and induced workers would be less pronounced, but would 

have relatively larger effects on community population, as most of these workers are assumed to be 

community residents. 

Housing 

Direct, indirect, and induced workers associated with the Proposed Action would require both temporary 

and longer-term housing resources. A portion of the drilling and field-development workforce, including 

ancillary facility construction workers whose work assignments would be temporary, would be likely to 

seek temporary housing resources while working in the project area. Such resources include dormitory 

units in mobile home and RV parks in Wamsutter, as well as motels, mobile home parks and RV Parks in 

Rawlins, Rock Springs, Wamsutter, and Baggs. Other resources have included a 250-bed complex in 

Wamsutter, now closed and relocated, and two smaller temporary-living facilities located on WY 789 

near Dad. 

Most production workers and a portion of drilling, completion, and gas-field service workers and indirect 

and induced employees would likely seek long-term housing resources in communities near the project 

area. For this assessment, long-term housing includes conventional single-family and multi-family 

housing and mobile homes, both on lots and in mobile home parks. 

Table 4.15-7 displays estimated Proposed Action-related demand for temporary and longer-term housing 

in communities near the study area for five periods: the first year of development and Years 5, 10, 15 

(following completion of drilling), and 20. Demand estimates for long-term housing are expressed in 

terms of units; demand for temporary housing is expressed in terms of beds. Temporary demand could be 

accommodated by motels and RV pads, which typically accommodate more than one bed per unit or by 

worker camps/temporary living facilities, which can house one or multiple beds per unit. 

In all communities, demand for both long-term and temporary housing increases sharply over the first 10 

years of activity of the Proposed Action. Demand for temporary housing eases while demand for longterm housing continues to increase for several more years, after which demand for housing is projected to 

decline dramatically.26 

26 Note that vendors and certain types of contractors will require short-term temporary housing, primarily motels throughout the 

production phase of the project. These short-term requirements have not been estimated. 

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Table 4.15-7. Proposed Action-related temporary and long-term housing demand 

Housing Demand Year 1 Year 5 Year 10 Year 15 Year 20 

Sweetwater County 

Rock Springs 

Long-term (units) 104 501 819 958 150 

Temporary (beds) 81 217 304 128 91 

Wamsutter 

Long-term (units) 13 63 102 120 19 

Temporary (beds) 122 325 456 192 137 

Green River 

Long-term (units) 10 50 82 96 15 

Temporary (beds) 0 0 0 0 0 

Sweetwater County Other 

Long-term (units) 3 13 20 24 4 

Temporary (beds) 0 0 0 0 0 

Sweetwater County total 

Long-term (units) 130 627 1,024 1,197 187 

Temporary (beds) 203 542 761 320 228 

Carbon County 

Rawlins 

Long-term (units) 31 219 371 422 66 

Temporary (beds) 33 88 124 52 37 

Baggs/LSRV 

Long-term (units) 7 49 83 95 15 

 Temporary (beds) 8 20 29 12 9 

Carbon County Other 

Long-term (units) 1 5 9 11 64 

Temporary (beds) 10 27 38 16 11 

Carbon County total 

Long-term (units) 39 274 463 528 83 

Temporary (beds) 51 135 190 80 57 

Source: SDLLC and BCLLC, using the REMI model. 

Several communities, including Rawlins, Rock Springs, and Wamsutter, have developed housing and/or 

infrastructure improvement plans that, if realized, would accommodate the long-term housing demand 

associated with the Proposed Action and other energy development. At present no communities have the 

existing available housing to accommodate the anticipated long-term demand. 

During late 2008 and early 2009 there was an increase in available long-term housing units throughout the 

study area as a result of the national economic slowdown and in Carbon County, due to substantial 

completion of Sinclair Refinery expansion construction. Still, most of the long-term housing required to 

fill the Proposed Action-related housing demand would need to be added through new construction, given 

that the Proposed Action would likely occur in the context of substantial regional natural gas 

development. 

Although there are adequate regional temporary housing resources to accommodate temporary housing 

demand associated with the Proposed Action, there would be localized shortages of temporary housing, 

particularly in Wamsutter. The closure of the BP Wamsutter base camp, which had 250 beds and was 

permitted for an additional 250 beds, has substantially reduced the availability of temporary housing 

resources within that community. If the pace of development within the project area accelerates, as 

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contemplated by the Proposed Action, additional worker housing would be required in Wamsutter. There 

could also be substantial competition for temporary housing from demand associated with the regional 

natural gas development projects and other planned and proposed energy development described in Table 

5.0-1. Development and expansion of temporary living facilities and potential expansions of motels, 

mobile homes and RV parks throughout the study area would be required to accommodate Proposed 

Action-related temporary housing demand if the Proposed Action occurred concurrently with other 

development. 

Project-related demand for housing would also be subject to variability in response to the anticipated 

year-to-year variances in the pace of development. Variations in drilling levels would primarily affect the 

number of temporary workers, which would correspondingly result in higher or lower demand for and 

occupancy of temporary housing resources. 

The substantial decrease in demand for long-term housing resources in communities following the 15­

year drilling and field-development phase of the Proposed Action could result in substantial shocks to 

community housing markets, including vacancies and a decrease in housing value, depending on other 

economic activities occurring in the area at that time. 

Community Infrastructure and Services 

The Proposed Action would affect community infrastructure and services in several ways. The increases 

in industrial activity within the project area and increases in traffic to and within the project area would 

result in demand for additional law enforcement, emergency management and response, and road 

maintenance services for Carbon and Sweetwater Counties and the volunteer emergency response 

agencies that serve these areas. The Proposed Action-related population increase in affected communities 

including Rawlins, Baggs/LSRV, Wamsutter, Rock Springs and Green River would experience increased 

demand for a wide range of community infrastructure and local government services. The increase in 

temporary and transient population would likely generate higher levels of demand for certain services 

including law enforcement and emergency medical treatment. County and municipal governments would 

receive revenues from the Proposed Action (assessed in the following section), which could help offset 

the costs of the additional services required to meet the demand, although municipal revenues generated 

directly by the project would be limited to sales and use tax revenues. Incremental revenues from 

development would typically lag development-related demand by months or in some cases, years. 

Community Infrastructure 

Expanding and improving community infrastructure to accommodate growth requires substantial leadtime and capital. With the possible exception of Wamsutter, demand for public facilities during the 

assessment period will result from a number of other projects and factors in addition to the project area. 

Consequently, while project area-related demand for public facilities may not by itself trigger a need for 

community infrastructure expansion, cumulative demand from the project area in combination with other 

natural gas and energy projects and other sources could trigger additional infrastructure needs. 

Because energy-related population growth occurred within the study area for several years prior to the 

current slow-down and additional growth was anticipated, most local governments expanded and 

improved some community facilities including water and wastewater systems, solid-waste disposal 

facilities, detention facilities, and a range of other facilities. For some local governments, further 

improvements in specific systems are planned. 

Solid Waste Disposal Facilities. Most communities and solid-waste management districts within the 

study area have implemented solid waste management plans and in some cases, expanded landfill 

capacities. The Carbon County communities within the study area (Rawlins and Baggs) are transporting 

their municipal solid waste to the Casper Regional Landfill. The City of Casper is permitted to operate the 

CRL on a 1,750 acre site; Phase I includes 88 acres and has an estimated capacity of 11,920,000 cubic 

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yards and a lifespan of 50 years. Five future cells also have estimated life spans of 50 years (Inberg-Miller 

Engineers 2009). 

The Sweetwater County communities in the study area (Wamsutter, Green River and Rock Springs) plan 

to transport their municipal solid waste to the Rock Springs Regional landfill. Much of the gas-field solid 

waste within the project area is also transported to the Rock Springs landfill. The Rock Springs Landfill, 

which will become the I-80 Solid Waste Management Planning Area landfill, has capacity for about 30 

years at current fill rates. The District has an additional 300 acres that may be used after the current 

facility reaches capacity. 

Through their participation in the solid-waste management districts, all communities within the study area 

should have capacity to accommodate the increase in solid-waste-disposal demand generated by the 

Proposed Action and alternatives, although some operating improvements will likely be required to 

accommodate the increased volumes associated with the Proposed Action, with associated increases in 

operating costs. Increased levels of drilling and development in the project area would likely be 

accompanied by increases in drilling and development in other natural gas fields in the study area. 

Implementation of the Proposed Action would increase fill rates at both regional and municipal landfills, 

hastening the date when expansion of existing landfills or development of new landfills would be 

required. 

Water. Water systems within the study area are operated by municipalities. All communities have 

adequate water rights and treatment and storage capacity or are in the process of improving their systems 

to provide adequate capacity to accommodate additional population. 

Although the main components of municipal water systems, with planned improvements, would be 

adequate to accommodate the growth associated with the Proposed Action, each municipality could 

encounter the need to expand or improve its water-distribution system to accommodate areas within the 

community that would develop housing to accommodate growth. Additionally, elevated levels of drilling 

and development in all gas fields in and near the project area could result in the need to expand water 

systems to serve new housing developments in each municipality, resulting in additional water system 

expenditures. 

Wastewater. Rawlins, Rock Springs, and Green River all have adequate wastewater treatment capacity to 

accommodate the population increment associated with the Proposed Action and other foreseen growth. 

Baggs and Wamsutter are currently in the planning stages of developing additional wastewater treatment 

capacity to accommodate foreseen growth. All municipalities have the potential to encounter costs to 

develop wastewater collection mains to serve areas of their communities that would accommodate new 

housing development and to expand or improve wastewater treatment systems to meet evolving 

regulatory standards. 

Criminal Detention Facilities. Carbon and Sweetwater counties each have relatively new criminaldetention facilities. The 78-bed Carbon County detention facility has been in operation since 2004. 

During the summer of 2009 the facility’s design capacity was exceeded several times; suggesting a 

shorter than expected 10- to 15-year design life for the facility. The Proposed Action would contribute to 

the potential need to expand the Carbon County Detention Facility during the 15-year development phase 

of the project. 

The Sweetwater County Detention Facility has a design capacity of 208 inmates. Recent occupancy has 

averaged about 110 inmates, or 53 percent of capacity. The facility was designed to allow for expansion 

on the same site while maximizing use of existing administrative facilities. The Sweetwater County 

Detention Facility should be adequate to accommodate the population increment associated with the 

Proposed Action. 

Hospitals. Major health-care institutions within the study area include the Memorial Hospital of Carbon 

County, which is undergoing major renovations, and Memorial Hospital of Sweetwater County, which 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—SOCIOECONOMICS
 

recently completed a major improvement and expansion project. In general, the expanded physical 

hospital facilities should be adequate to accommodate the population increment associated with the 

Proposed Action. Both hospitals would experience increased use of emergency rooms and staff to treat 

patients, including gas-field development workers who do not have local primary-care physicians. 

Consequently the Proposed Action, in concert with other energy-development activities, could result in 

strains on emergency-room facilities and staff. On the other hand, recent development and expansion of 

urgent care facilities in Rawlins and Rock Springs could reduce this impact. 

Both hospitals experienced substantial increases in uncollected debt attributed to increasing numbers of 

patients without health-care insurance and indigent patients during periods of expanded energy 

development. Uncollected debt would likely increase under the Proposed Action and increases in other 

energy development. 

Physician and health-care professional recruitment and retention has also been a problem in the past. The 

Proposed Action and other energy development would increase demand for physicians and likely 

contribute to increases in housing costs, which could contribute to difficulties in physician and health-care 

professional recruitment. 

Other Municipal Infrastructure. As discussed below, each of the counties and communities within the 

study area will require additional employees and equipment to accommodate demand from the 

incremental population growth associated with the Proposed Action and other energy development. New 

employees will require office space and new equipment will require storage space in buildings or storage 

yards. Recreational facilities such as parks, libraries, and recreation centers will receive additional 

demand and may require expansion, improvement, or increases in staffing. It is likely that counties and 

municipalities would be required to develop new facilities and expand and improve existing facilities to 

accommodate the additional demand associated with the Proposed Action and other energy development. 

Community Services 

Demand associated with the incremental population associated with the Proposed Action would result in 

additional demand for community services, which, in turn, would require additional staff, equipment, and 

operating expenditures. 

County sheriff’s departments and local emergency-management and response agencies would be required 

to increase resources to maintain the current level of services (LOS) they provide to the project area and 

on highways and roads that provide access to the area. County road and bridge departments would 

experience demands for additional road maintenance for county roads within the project area. County 

governments would experience pressure to expand all essential services to accommodate the additional 

population, housing, commercial, and community infrastructure associated with the Proposed Action and 

other energy development. As discussed in the following section on fiscal effects, counties would receive 

ad valorem property taxes on certain natural gas facilities and production and sales and use tax revenues 

to help offset the cost of increased service demand. 

Affected communities and certain special districts within the study area would also experience increased 

demand for services associated with the Proposed Action. For municipalities, this demand would 

generally be driven by the incremental population associated with the Proposed Action, although the 

specific demographics of the temporary and transient, single-status, working-age male population would 

likely result in higher demand for law enforcement and emergency medical services. 

Communities are much more limited than counties in their ability to fund the needed increases in 

municipal services. As is discussed in the fiscal section, direct revenues generated by the Proposed Action 

to communities would accrue primarily in the form of sales and use tax revenues, although the Proposed 

Action could indirectly result in additional ad valorem tax revenues on commercial and residential 

development and from relatively larger distributions from various shared revenues for which the 

allocation formulas are population based. To assist local communities affected by energy development, 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—SOCIOECONOMICS
 

the Wyoming Office of State Lands and Investments administers a number of grants and loans funded out 

of mineral revenues that local governments can use to fund infrastructure improvements, and a number of 

energy companies have provided funds to local governments to develop facilities to accommodate 

energy-related growth, particularly in Wamsutter. 

Public Education 

Three school districts would be affected by the Proposed Action, Sweetwater County School Districts 1 

and 2 and Carbon County School District 1. Table 4.15-8 below summarizes the projected increases in 

student enrollments in these school districts for the first 20 years of the Proposed Action. 

Table 4.15-8. Projected Proposed Action-related school enrollment: Years 1 through 20 

District/(Location)/Grades Year 1 Year 5 Year 10 Year 15 Year 20 

Sweetwater #1 (Rock Springs) 

 Elementary: K–4 (ages 5–9) 16 16 125 211 170

 Elementary: 5 & 6 (ages 10 & 11) 6 6 11 69 69

 Junior High: 7 & 8 (ages 12 & 13) 5 5 10 45 66

 High School: 9–12 (ages 14–17) 11 11 22 29 129

 Rock Springs Subtotal 38 38 168 354 434 

Sweetwater # 1 (Wamsutter)

 Wamsutter Elem/Middle (K–8) 6 6 37 81 76 

Sweetwater #1 Total 44 44 205 435 510 

Sweetwater #2 (Green River) 

 Elementary: K–4 (ages 5–9) 2 2 14 23 19

 Elementary: 5 & 6 (ages 10 & 11) 1 1 1 7 8 

 Junior High: 7 & 8 (ages 12 & 13) 1 1 1 5 7 

 High School: 9–12 (ages 14–17) 1 1 2 3 11

 Sweetwater #2 Total 5 5 18 38 45 

Carbon District #1 (Rawlins) 

 Elementary: K–5 (ages 5–10) 6 6 46 90 77

 Middle: 6–8 (ages 11–13) 2 2 6 26 35

 High School: 9–12 3 3 7 10 34

 Rawlins Total 11 11 59 126 146 

Carbon District #1 (Baggs/LSRV) 

LSRV K–12 4 4 15 32 36

 Carbon #1 Total 15 15 74 158 182 

Source: SDLLC and BCLLC, using the REMI model. 

Proposed Action-related increases in school enrollment would follow the trends in resident population 

increase, climbing over time as long-term employment increases, but then declining as drilling activity is 

completed and the production levels begin to fall (see Figure 4.15-9). 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—SOCIOECONOMICS
 

0 

100 

200 

300 

400 

500 

600 

700 

800 

900 

1000 

Yr 1 Yr 5 Yr 9 Yr 13 Yr 17 Yr 21 Yr 25 

Project-Related School-Age Children 

High School 

Middle School 

Elementary 

Figure 4.15-9. Increases in school-age children due to the Proposed Action 

Source: SDLLC and BCLLC, using the REMI model. 

Proposed Action-related enrollment in SCSD #1 schools in Rock Springs would increase from an 

estimated 38 students in Year 1 to 434 in Year 20. Based on recent enrollment trends, the incremental 

increases in student enrollment would initially be more heavily concentrated in kindergarten and the 

lower grades, but shifting into the middle and high school grades over time. Considering cumulative 

increases in enrollment for other energy development, the Proposed Action-related enrollment would 

exceed the capacity of the current schools during the 15-year field-development period, depending on 

other concurrent levels of energy development in the region. If SCSD #1 is able to anticipate the increase 

in demand in a timely fashion and seek and obtain approval from the Wyoming School Facilities 

Commission for new school facilities, the demand could likely be accommodated without long periods of 

overcrowding. Depending on the date of approval, the length of time required to construct such facilities 

and the concurrent level of energy development, modular classrooms could be required to accommodate 

some Proposed Action-related students in the interim. 

Proposed Action-related enrollment in the SCSD #1 K–8 school in Wamsutter would increase from an 

estimated six students in Year 1 to 81 in Year 15, decreasing thereafter. The current school facility in 

Wamsutter would require expansion to accommodate this increase in enrollment. 

SCSD #2, based in Green River, would experience much lower impacts on student enrollments than 

would SCSD #1. Proposed Action-related enrollment in the SCSD #2 in Green River would increase from 

an estimated five students in Year 1 to 45 in Year 20. SCSD #2 could accommodate the anticipated 

increase in enrollment with current school facilities, depending on the level of other energy development 

concurrent with the Proposed Action. 

Proposed Action-related enrollment in CCSD #1 in Rawlins would increase from an estimated 15 

students in Year 1 to 182 in Year 20. The school-age enrollments would begin declining thereafter. CCSD 

#1 schools in Rawlins could nominally accommodate the Proposed Action-related increases in 

enrollment, but given that increases in drilling and field development in the project area are likely to be 

accompanied by increases in drilling and development in other fields in the study area, the capacities of 

Rawlins schools are likely to be exceeded during the 15-year drilling period. The available capacities of 

the newly completed Rawlins Elementary School and the 500-student-capacity high school authorized by 

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the Wyoming School Facilities Commission would be nearly exceeded by the projected Proposed Actionrelated increase in enrollment alone, not considering increases in enrollment related to other energy 

development. 

The LSRV K–12 schools in Baggs could accommodate the projected Proposed Action-related increase in 

enrollment, but would absorb most available capacity such that enrollment associated with other nearby 

energy development could result in enrollment increases beyond available capacities, particularly toward 

the end of the 15-year drilling phase and the subsequent five years of project operations. 

As discussed in Section 1.7.4 of the Socioeconomic Technical Report, the Wyoming School Foundation 

Program provides a guaranteed level of funding to every school district in the state, with funding based on 

numbers of students, classrooms, and other factors such as adjustments for small schools, transportation, 

special programs, and the cost of living. Consequently, the school districts affected by Proposed Actionrelated increases in enrollment should have the financial resources to fund the required increases in 

teachers and operating costs, although the districts would experience increased costs to provide for special 

needs of incoming students, including programs for transient students and additional teachers to serve 

English-language learners. Wyoming teacher salaries are relatively high, but districts may have to provide 

housing to recruit the required number of teachers. Districts may also have trouble recruiting and 

retaining custodians and school-bus drivers if the area experiences another surge in energy development, 

given the wage competition during energy booms. 

Fiscal Effects 

Projections of future natural gas and condensate production provide the foundation for projecting the 

Proposed Action-related mineral development revenue.27 Projected production was derived using typical 

well-production data provided by the BLM Wyoming’s Reservoir Management Group (RMG) and the 

projected numbers of new wells associated with the Proposed Action. 

Estimated total production for the Proposed Action (and Alternative A) over the life of the field is 12.02 

Tcf of gas and 167.3 million bbls of liquid condensate. The estimated market value of that production, 

based on assumed future commodity prices of $4.00 per thousand cubic feet (Mcf) of gas28 and $40.00 per 

bbl of liquid condensates is $52.0 billion ($2010); $45.6 billion for gas and $6.4 billion for condensate.29 

The value of gas and condensate sales under the Proposed Action would reflect the trends in annual 

production, increasing over time as long as the anticipated level of new development occurs, but declining 

steadily once new development ceases. At the level of development associated with the Proposed Action, 

the incremental annual sales would exceed $1 billion within three to four years and remain above that 

mark for approximately 20 years. Projected annual sales value would peak at approximately $2.92 billion 

for the Proposed Action (Figure 4.15-10). Sales of natural gas would account for nearly 90 percent of the 

total, $2.6 billion. In 2007, a total value of $1.37 billion in natural gas and $441 million in crude oil and 

condensate was produced in Carbon and Sweetwater counties. Despite substantial increases in natural gas 

production, the corresponding production values in 2009 were $949 million and $330 million, 

respectively. 

27 The gas and condensate volumes associated with the Proposed Action would be in addition to gas and condensate produced 

from wells already developed and allowed under previous NEPA actions. 

28 The $4.00/mcf commodity price for natural gas is net of an assumed $0.50/mcf gas processing allowance. 

29 Projected market value of sales assumes 95 percent of projected production is sold. 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—SOCIOECONOMICS
 

$0.0 

$0.5 

$1.0 

$1.5 

$2.0 

$2.5 

$3.0 

$3.5 

Yr 1 Yr 5 Yr 9 Yr 13 Yr 17 Yr 21 Yr 25 Yr 29 Yr 33 Yr 37 Yr 41 Yr 45 

Billions

Value of Gas 

Value of Condensate 

Figure 4.15-10. Projected value, annual natural gas and liquid condensate production, Proposed Action 

Source: SDLLC and BCLLC 

Production and the value of sales would decline rapidly after full-field development occurs (Year 15), 

decreasing by approximately 65 percent in the subsequent decade. 

Severance Taxes 

The State of Wyoming levies a severance tax on all minerals produced in the state. Current severance tax 

rates are 6.0 percent on condensate and natural gas. Severance tax rates are applied to the taxable value at 

the point where the production process is complete, before processing and transportation. Because 

processing adds value to the raw gas, the effective tax rate relative to market value is less than the 

nominal rate. In 2007, the Wyoming Legislative Services Office estimated the effective rates at 5.46 

percent for condensate and 4.86 percent for natural gas. Applying these rates to the project values for the 

Proposed Action yields severance taxes of $818 million in the first decade as development continues and 

production climbs; $1.13 billion in the second decade during which peak production occurs; and a total of 

nearly $2.6 billion over the life of the field (Figure 4.15-10 and Table 4.15-9). 

Table 4.15-9. Projected state severance tax revenues and initial allocations, Proposed Action ($2010) 

Year 1–10 

Subtotal 

Year 11–20 

Subtotal 

Year 21–30 

Subtotal 

Life of Project 

Total (40+ yrs) 

Permanent Wyoming Mineral 

Trust Fund, 41.7% $ 341,020,000 $ 468,900,000 $ 185,770,000 $ 1,066,450,000 

General Fund, 19.4% 159,700,000 219,580,000 86,990,000 499,410,000 

Budget Reserve, 38.6% 317,730,000 436,880,000 173,080,000 993,620,000 

Total state severance taxes $ 818,450,000 $ 1,125,360,000 $ 445,840,000 $ 2,559,480,000 

Source: SDLLC and BCLLC 

Severance tax receipts collected by the state are allocated to the Permanent Wyoming Mineral Trust Fund 

(PWMTF) and to the Severance Tax Distribution Account; further distributions to numerous other funds 

are made from the latter. Those subsequent distributions are subject to a legislatively established 

aggregate cap of $155 million on annual revenue deposits. Revenue in excess of the annual cap is 

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distributed one-third to the state’s general fund and two-thirds to the budget reserve account.30 The high 

levels of mineral production and prices over the past decade have consistently generated sufficient 

severance taxes for such distributions to the general fund and budget reserve account. Under the assumed 

allocations, the Proposed Action would generate nearly $1.1 billion to the PWMTF, nearly $500 million 

to the state’s General Fund, and more than $993 million to the Budget Reserve Account. 

Federal Mineral Royalties 

Federal mineral royalties (FMR), based on a rate of 12.5 percent, would be derived on the value of 

production from the federal mineral estate. The federal mineral estate encompasses about 59 percent of 

the total oil and gas mineral estate in the project area. Total projected FMR of $3.8 billion would be 

generated from the Proposed Action over the life of the field.31 Of that total, nearly $1.96 billion would 

accrue to the Federal Treasury, with $1.88 billion in disbursements to the State of Wyoming (Table 4.15-

10). 

Table 4.15-10. Projected federal mineral royalties and distribution ($2010) 

Year 1–10 

Subtotal 

Year 11–20 

Subtotal 

Year 21–30 

Subtotal 

Life of Project 

Total (40+ yrs) 

Federal Treasury (51%) $ 625,690,000 $ 860,330,000 $ 340,830,000 $ 1,956,680,000 

State of Wyoming 

(49%) 

601,150,000 826,590,000 327,470,000 1,879,950,000 

Total FMR $1,226,840,000 $1,686,920,000 $ 668,300,000 $ 3,836,630,000 

Source: SDLLC and BCLLC 

As with the state’s severance taxes, the state’s share of FMR is allocated according to a tiered allocation 

formula. The state first deducts 1 percent for administration. Thereafter, the next $200 million in annual 

receipts is distributed among seven different funds, e.g., a county highways fund and school capital 

construction account. FMR in excess of $200 million are distributed as follows: one-third to the School 

Foundation Program and two-thirds to the state Budget Reserve Account. The $200 million annual cap 

has been exceeded consistently for more than a decade, such that incremental revenues flow to the 

education and budget reserve accounts. In recent years, a portion of the School Foundation Program 

distributions has been diverted to two special education accounts: the Hathaway and Higher Education 

endowments. The Hathaway endowment provides scholarships for high-school graduates entering college 

and the Higher Education endowment allows the University of Wyoming (UW) to fund a number of 

endowed faculty positions and acquire materials and resources to support those chairs. Projected 

allocations of the $1.88 billion in FMR accruing to the state are $626 million for education and $1.25 

billion to the state’s Budget Reserve Account (Table 4.15-11). 

30 The high levels of mineral production and commodity prices have consistently generated sufficient severance tax revenue to 

exceed the cap, such that additional revenues flow to the general fund and budget reserve account. The resulting distribution, 

which is used in this analysis, is 41.7 percent to the PWMTF, 19.4 percent to the General Fund and 38.9 percent to the Budget 

Reserve Account. 

31 A “temporary” change in the distribution of FMR was recently enacted by Congress and the President. Under the new formula, 51 

percent of the revenue accrues to the federal government and 49 percent to the state, rather than the prior 50/50 split net of a 1 

percent administrative processing fee. The forecasts reflect the current allocation formula. 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—SOCIOECONOMICS 

Table 4.15-11. Projected allocation of Wyoming's share of federal mineral royalties, Proposed Action 

($2010) 

Year 1–10 

Subtotal 

Year 11–20 

Subtotal 

Year 21–30 

Subtotal 

Life of Project 

Total (40+ yrs) 

Wyoming School Foundation $ 200,180,000 $ 275,250,000 $ 109,050,000 $ 626,020,000 

State budget reserve 400,970,000 551,340,000 218,420,000 1,253,930,000 

Total state share of FMR $ 601,150,000 $ 826,590,000 $ 327,470,000 $1,879,950,000 

Source: SDLLC and BCLLC 

State Royalties 

Like the federal government, the State of Wyoming collects mineral royalties on production from the 

state’s mineral estate. The state’s interest in the project area oil and gas estate is estimated at 2 percent, 

yielding an estimated $169 million ($2010) in royalties over the life of the field, assuming a 12.5-percent 

royalty rate. State mineral royalties accrue to the Wyoming Office of State Lands and Investments. Those 

revenues are in turn used to benefit public education and other designated state institutions, such as the 

Wyoming State Hospital. 

Gross Products and Local Ad Valorem Taxes 

The gross products tax is based on the value of the minerals produced in the previous year. The taxable 

value is determined by the state, but the tax is levied and collected by local taxing jurisdictions based on 

the applicable tax levy. Consequently, the tax is akin to local ad valorem property taxes. Based on the 

location of the wells and mineral resources, the taxing districts most directly affected by the Proposed 

Action include Sweetwater County, Carbon County, SCSD #1 and CCSD #1. A mandatory statewide mill 

levy to support public education via the Wyoming School Foundation program would be collected by the 

two counties, with the proceeds being transferred to the state. Projected gross products tax revenue from 

the Proposed Action, assuming current mill levies over the life of the project, would total $3.11 billion 

(Table 4.15-12). Of that total, 13.8 percent would accrue to Sweetwater County, 7.4 percent to Carbon 

County, 43.2 percent to SCSD #1, 25.0 percent to CCSD #1, and 10.6 percent to the Wyoming School 

Foundation Program.32 

32 The allocation to school districts assumes that the two local districts retain all of the additional tax revenue to meet increases in 

operating costs associated with changes in enrollment, rather than being subject to the “recapture” provisions under the Wyoming 

School Finance Act. Under those provisions, locally generated tax revenues in excess of the amount a district is authorized to 

expend under the financing equalization program are transferred to the state to help support statewide education. As a result, 

school districts realize little significant fiscal benefits from high levels of mineral development within their boundaries. Both SCSD 

#1 and CCSD #2 have been subject to the recapture provisions, CCSD # 1 as recently as 2010. In 2010, CCSD #1 contributed 

$15.8 million of its ad valorem tax collections to the School Foundation Program. 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—SOCIOECONOMICS 

Table 4.15-12. Projected gross products and ad valorem taxes to local counties and school districts, 

Proposed Action ($2008) 

Year 1–10 

Subtotal 

Year 11–20 

Subtotal 

Year 21–30 

Subtotal 

Life of Project 

(40+ years) 

Sweetwater County $ 94,360,000 $ 162,330,000 $ 68,150,000 $ 354,130,000 

Carbon County 50,810,000 87,410,000 36,700,000 190,680,000 

Sweetwater County School 

District #11

 296,470,000 510,000,000 214,120,000 1,112,560,000 

Carbon County School District 

#1 1 171,490,000 295,010,000 123,860,000 643,560,000 

Wyoming School Foundation 

Program ** 72,580,000 124,860,000 52,420,000 272,380,000 

 Combined totals $685,710,000 $1,179,610,000 $495,250,000 $2,573,310,000 

1

 These allocations assume the locally generated taxes are retained by the school districts and not subject to transfer to the 

state under the “recapture” provisions of the Wyoming School Finance Act. Both SCSD #1 and CCSD #2 have been subject to 

the recapture provisions, CCSD # 1 as recently as 2010. In 2010, CCSD #1 contributed $15.8 million of its ad valorem tax 

collections to the School Foundation Program. 

Source: SDLLC and BCLLC 

In addition to the gross products tax on production, the counties, school districts, and some local taxing 

districts (special service districts and communities) would levy ad valorem taxes on the production 

equipment, pipelines, and other real improvements associated with the project, as well as residential, 

commercial, and industrial development generated by the project. Local communities would realize 

additional ad valorem tax revenues from new real-estate development supported by the project and the 

effects of demand on values of existing real estate. The affected local taxing districts include: Sweetwater 

County Conservation District; Sweetwater County Solid Waste District #2; Sweetwater County Weed and 

Pest District; Western Wyoming Community College; the Baggs Cemetery and Solid Waste Disposal 

districts; the Little Snake River Conservation, Museum, and Rural Mental Health districts; Carbon 

County Weed and Pest District; the cities of Rock Springs, Green River, and Rawlins, and the towns of 

Wamsutter and Baggs. Project-related ad valorem tax revenues accruing to these districts are not 

estimated in this analysis. 

Sales and Use Taxes 

Future expenditures for materials, supplies, and equipment associated with new well development and 

subject to sales and use tax are projected to exceed $2.8 billion under the Proposed Action. That total 

excludes taxable capital expenditures associated with any new centralized gas-processing facilities or 

transmission pipelines. Based on the locations of the wells and the concentration of well drilling and oil 

and gas service firms in Rock Springs, approximately two-thirds of that total, $1.9 billion, would occur in 

Sweetwater County. Taxable expenditures of $340 million by the Operators are assumed to occur in 

Carbon County, and $626 million are assumed to occur elsewhere in Wyoming or out of state.33 The latter 

would be subject to use tax when brought into the state.34 

The state imposes a 4.0-percent general sales and use tax on such purchases. Sweetwater County’s tax 

rate is 2.0 percent (1.0 percent general purpose and 1.0 percent specific-purpose option). Carbon County 

historically levied only the 1.0-percent general purpose tax, but added a 1.0-percent specific purpose tax 

effective April 2009. Those tax rates, assumed to remain constant, would yield nearly $161 million in 

33 These estimates are based on information provided by the Operators to SDLLC and BCLLC and the development of 8,950 new 

wells. 

34 Additional taxable purchases would be made in conjunction with ongoing production and field operations. However, data to 

estimate such purchases was not available at the time of the analysis. 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—SOCIOECONOMICS
 

sales and use taxes; $115.8 million from the state’s 4.0-percent rate, $38.2 million in locally imposed 

taxes in Sweetwater County and $6.7 million on sales in Carbon County.35 

Projected distributions of the state’s sales and use tax receipts, based on the current statutorily established 

allocations, would include $80.3 million to the general fund and $35.5 million to local governments. The 

distributions to local governments, which are primarily a function of population distribution in the 2000 

Census, would include: $4.2 million to Sweetwater County, $1.3 million to Carbon County, and $30.0 

million to other local governments.36 Each county retains a portion of its distribution from the state; the 

remainder is distributed to cities and towns in the respective counties. Combining the locally generated 

sales and use tax and distributions from the state yields totals of $42.4 million in Sweetwater County and 

$8.1 million in Carbon County; more than $2.8 million in Sweetwater County and $534,000 in Carbon 

County on an annual basis. 

The Proposed Action would stimulate higher consumer expenditures in the regional economy and 

Sweetwater and Carbon counties and local municipalities would benefit from sales and use tax receipts 

derived from the consumer expenditures. All sectors of the economy would benefit from the boost in 

consumer sales, with the most pronounced effects on the retail trade, food and beverage, and lodging and 

entertainment sectors. Incremental consumer expenditures would increase over time, as production and 

transportation employment increases, augmenting the incremental expenditures associated with the 

development phase. The incremental expenditures would drop sharply after the development phase is 

completed. 

Revenue Summary 

The combined total public-sector revenues from the identified sources are projected to exceed $9.3 billion 

over the life of the field. FMR totaling $3.8 billion would account for the single largest share of the total, 

41.0 percent (Table 4.15-13 and Figure 4.15-11) though nearly one-half of that total would be distributed 

to the State of Wyoming. The state would garner another $2.7 billion in severance taxes and state mineral 

royalties. Sweetwater and Carbon Counties would realize a combined total of $544 million in gross 

products and ad valorem taxes and the two school districts and Wyoming State Foundation program 

would collectively receive nearly $2.0 billion in tax revenues. 

35 The total assumes all non-local purchases are made out of state. If purchases are made elsewhere in Wyoming, additional sales 

taxes could be generated for that county, but the revenues accruing to Sweetwater and Carbon counties would be unaffected. 

36 The resident populations of Sweetwater and Carbon county, expressed as a percentage of Wyoming’s total population, increased 

slightly between 2000 and 2010. Consequently, assuming no changes in the allocation formula by the Wyoming Legislature, the 

shares of local distributions from the state’s receipts may increase slightly in the future. 

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Table 4.15-13. Projected public-sector taxes and royalties on gas and condensate production, 

Proposed Action ($2010) 

Year 1–10 

Subtotal 

Year 11–20 

Subtotal 

Year 21–30 

Subtotal 

Life of Project 

Total (40+ yrs) 

Severance tax $ 818,450,000 $ 1,125,360,000 $ 445,840,000 $ 2,559,480,000 

Federal Mineral Royalties 1,226,840,000 1,686,920,000 668,300,000 3,836,630,000 

State Mineral Royalties 54,030,000 74,300,000 29,430,000 168,960,000 

Gross products / ad 

valorem, Counties 1 145,170,000 249,740,000 104,850,000 544,810,000 

Gross products / ad 

valorem, Schools 1 540,540,000 929,870,000 390,400,000 2,028,500,000 

Sales and use taxes, 

development-related 

156,610,000 66,660,000 n/a 223,270,000

 Total combined $2,941,640,000 $4,132,850,000 $1,638,820,000 $9,361,650,000 

1

 These allocations assume the locally generated taxes are retained by the school districts and not subject to transfer to the 

state under the “recapture” provisions of the Wyoming School Finance Act. 

Source: SDLLC and BCLLC 

27.3% 

41.0% 

1.8% 

5.8% 

21.7% 

2.4% 

Severance Tax Federal Mineral Royalties 

State Mineral Royalties Ad Valorem Tax-Counties 

Ad Valorem Tax-Schools Sales and Use 

Figure 4.15-11. Distribution of public-sector taxes and royalties, Proposed Action 

Source: SDLLC and BCLLC 

Local Public Sector Expenditures 

Although the revenues generated to the public sector by the Proposed Action would be substantial over 

time, local and state governments would correspondingly be required to make substantial expenditures to 

respond to demand from development activities and from the population associated with the Proposed 

Action. Many of the required infrastructure and service expenditures were identified and discussed 

conceptually in the preceding Community Infrastructure and Services section. The amount and timing of 

expenditures that local governments might make in response to development are not known and would 

depend in part on the concurrent level of development throughout the study area. 

In the past, local governments have often had to respond to service demand from energy development 

prior to receiving substantial revenues from that development. In the case of major infrastructure 

investments, local governments assume substantial risk that the development will continue and generate 

adequate revenue to pay for the investment. This phenomenon has been called the “tax lead-time 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—SOCIOECONOMICS
 

problem” (Governors Committee on Oil Shale Environmental Problems 1974), but might be more 

appropriately called the “tax lag-time problem,” in that the receipt of adequate tax revenues lag the point 

in time at which local governments incur cost to serve development and growth. 

Another issue alluded to elsewhere in this assessment is the “jurisdictional mismatch problem,” in which 

development-related tax revenues do not accrue in sufficient amounts to the local governments affected 

by development-related impacts. In Wyoming, ad valorem taxes on natural gas production and facilities 

typically do not accrue to municipalities, where most of the population-related impacts occur. 

Municipalities must rely on development-related sales and use taxes, which are often inadequate to fund 

expenditures to serve development and can diminish relatively rapidly when development slows. 

These are historical problems that have accompanied energy and other forms of natural-resource 

development in Wyoming and much of the west. The magnitude of these problems in relation to the 

Proposed Action will depend in part on the magnitude of concurrent energy development in the study 

area. As previously noted, most local governments in the study area have expanded infrastructure during 

past periods of energy development, so there is some capacity for growth in infrastructure in the affected 

communities. Additionally, production-related revenues from existing wells within the project area will 

provide revenue streams for counties, school districts, the Wyoming School Foundation Fund and some 

special districts as future development occurs. 

Social Effects 

Many of the social effects of the last natural gas boom discussed in Section 3.15.7 could occur under the 

Proposed Action, particularly if substantial concurrent development were to occur in other parts of the 

study area. The availability of a relatively large number of high-paying jobs and corresponding low 

regional unemployment would again be seen as positive aspects of development. Many of the current 

residents of Carbon and Sweetwater counties are associated with energy industries and residents of all 

affected communities are familiar with energy development. But as the population in affected 

communities would grow as a result of the Proposed Action and other energy development, the 

proportion of newcomers and the numbers of temporary and transient persons in affected communities 

would increase. This trend has been associated with decreased community cohesion and increases in 

certain types of crime including those involving drugs, alcohol, and minor disturbances and assaults (see 

Section 3.15.4.1). 

Conversely, as more families relocate to communities, more commercial and community infrastructure 

would be available for newcomers and long-time residents alike. Community infrastructure and services 

would likely be strained and commercial establishments would experience some crowding in some 

communities during the early part of the development period, particularly if increases in development in 

the project area coincided with development elsewhere in the study area. 

Each of the communities within the CD-C study area would be affected differently by population growth 

associated with the Proposed Action. Rawlins and Rock Springs have embarked on housing and 

infrastructure development and community revitalization efforts. Both of these communities have 

initiated programs to preserve and redevelop portions of their historic downtown areas and have instituted 

and expanded cultural and recreational events that offer venues for newcomers and long-time residents to 

socialize. Wamsutter has an extensive program to develop and expand both physical and commercial 

infrastructure and housing resources and has enlisted participation by natural gas companies and the State 

of Wyoming in their efforts. Baggs is expanding and improving infrastructure to accommodate growth 

and the social effects of growth on this relatively close-knit ranching and outdoor recreation community 

will present unique challenges. However, the relatively modest level of growth associated with the 

Proposed Action and the community’s experience with prior and ongoing energy development will likely 

soften these effects. Green River would receive proportionately the smallest amount of growth from the 

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Proposed Action and is likely to host few temporary workers, so adverse social effects of the Proposed 

Action would likely be minimal in that community. 

Although the value of environmental amenities and outdoor recreation for residents of the study area is 

relatively well-documented, social effects of the change in environmental amenities associated with the 

Proposed Action are likely to be minimal. The fact that much of the project area is already developed and 

industrialized would diminish concern for further changes in most environmental amenities. The 

exceptions would be areas that are considered sensitive such as the sage-grouse lek complex southeast of 

Creston, the small portion of the Red Lake Dunes Citizens’ Proposed Wilderness that extends into the 

northwestern part of the project area, and the Chain Lakes Wildlife Habitat Management Area. 

The displacement of grazing permittees from the most intensively developed areas of the CD-C project 

area would be a substantial social impact, particularly if the ranching families who hold the allotments 

exit the ranching business. Ranching is an important element of the culture in the study area and further 

reductions in the ranching community would be of concern for many residents. 

Environmental Justice 

No environmental justice populations have been identified within or in areas immediately adjacent to the 

project area. Although some communities in this area have concentrations of racial and ethnic minority 

populations slightly higher than the statewide averages, the percentages are not meaningfully higher with 

the exception of Rawlins and that minority population is in large part attributable to the racial 

composition of the inmate population at the Wyoming State Penitentiary. Rawlins is 25 miles from the 

eastern boundary of the project area; consequently, the inmate population is unlikely to be affected by 

human health or environmental effects of the Proposed Action. 

The percentage of persons in poverty within and immediately adjacent to the project area is lower than the 

statewide average. The percentage of persons in poverty in Carbon County is slightly higher than the 

statewide average as a result of the population associated with the Wyoming State Penitentiary, but again, 

that population is unlikely to be affected by the activities associated with the Proposed Action. 

Based on the foregoing, no disproportionately high and adverse human health or environmental effects on 

minority or low-income populations are anticipated under the Proposed Action. 

4.15.2.3 Alternative A: 100-Percent Vertical Drilling 

Employment 

Like the Proposed Action, Alternative A assumes a total of 8,950 new wells would be drilled over a 15­

year period. Alternative A assumes that all wells would be drilled vertically from single-well pads. The 

shift to all single-well pads would require more rigs to drill the same number of wells each year compared 

to the Proposed Action. Projected long-term gas, condensate, and water production would be the same as 

under the Proposed Action. Applying the work-crew concept developed for the Proposed Action to 

Alternative A yields an increase of 15 to 20 percent in the number of direct onsite jobs (about 150) and 

200 to 210 total direct jobs as compared to the Proposed Action. Estimated long-term production and 

transportation employment would be slightly higher than for the Proposed Action due to the reduced 

efficiencies of servicing the higher number of single-well pads. 

The additional direct employment would support more indirect and induced employment, as well as 

triggering additional population growth. Total peak incremental employment under Alternative A would 

average about 400 more jobs than under the Proposed Action during the 15-year development phase 

(Figure 4.15-12). The majority of the added jobs would be based in Sweetwater County. 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—SOCIOECONOMICS
 

-3.0 

-1.5 

0.0 

1.5 

3.0 

4.5 

6.0 

Yr 1 Yr 3 Yr 5 Yr 7 Yr 9 Yr 11 Yr 13 Yr 15 Yr 17 Yr 19

Incremental Jobs (x 1,000) 

Proposed Action Alternative A 

Figure 4.15-12. Total incremental employment, Alternative A compared with the Proposed Action 

Sources: SDLLC & BCLLC based on CD-C Operators employment estimates and REMI model output 

Following the completion of new well development, incremental employment under Alternative A would 

be comparable to that under the Proposed Action, because Alternative A would have similar long-term 

direct production and transportation employment requirements. 

Population 

Projected population growth under Alternative A would mirror employment impacts, with the peak 

incremental population eventually reaching 4,464 residents, approximately 450 higher than under the 

Proposed Action (Table 4.15-14). The majority of the higher population would likely reside in 

Sweetwater County, particularly in Rock Springs. Alternative A would also result in higher net inmigration and an influx of temporary non-resident workers during the initial years of implementation, but 

also higher out-migration following the completion of new well development. 

Table 4.15-14. Incremental resident population impacts from Alternative A 

Year 1 Year 5 Year 10 Year 15 Year 20 

Alternative A 353 2,054 3,664 4,464 1,028 

Proposed Action 303 1,759 3,192 4,018 1,059 

Difference 50 295 472 446 -31 

Source: SDLLC and BCLLC, using the REMI model 

Most of the difference in population change would occur in Rock Springs and Rawlins, although the 

magnitudes of those differences would be limited in comparison to either the current population or the 

incremental growth associated with the Proposed Action. 

Other Socioeconomic Effects 

The relatively minor differences in community population between Alternative A and the Proposed 

Action would result in minor differences in housing demand, demand for community infrastructure and 

local government services, and increases in public-school enrollment. Rock Springs and Rawlins would 

likely experience a small increase in temporary workers resulting in a corresponding increase for services 

associated with the predominantly working-age-male demographics of that workforce. 

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Fiscal Effects 

Alternative A includes the same number of wells as the Proposed Action, both in total and on an annual 

basis. However, all of the wells would be drilled from single-bore pads. The projected production is also 

equivalent to that under the Proposed Action. Consequently, projected revenues from state severance 

taxes, FMR, state mineral royalties, and gross products/ad valorem taxes would be comparable to those 

under the Proposed Action: approximately $9.4 billion over the life of the field (Table 4.15-15). 

Table 4.15-15. Summary of projected public-sector taxes and royalties on gas and condensate 

production, Alternative A ($2010) 

Year 1–10 

Subtotal 

Year 11–20 

Subtotal 

Year 21–30 

Subtotal 

Life of Project 

Total (40+ yrs) 

Severance tax $ 818,450,000 $1,125,360,000 $ 445,840,000 $ 2,559,480,000 

Federal mineral royalties 1,226,840,000 1,686,920,000 668,300,000 3,836,630,000 

State mineral royalties 54,030,000 74,300,000 29,430,000 168,960,000 

Gross production / ad 

valorem tax, counties ** 145,170,000 249,740,000 104,850,000 544,810,000 

Gross production / ad 

valorem tax, schools ** 540,540,000 929,870,000 390,400,000 2,028,500,000 

Sales and use taxes - 156,610,000 66,660,000 n/a 223,270,000

 Total combined $2,941,640,000 $4,132,850,000 $1,638,820,000 $9,361,650,000 

** These allocations assume the locally generated taxes are retained by the school districts and not subject to transfer to the 

state under the “recapture” provisions of the Wyoming School Finance Act. 

Source: SDLLC and BCLLC 

Sales and use tax revenues derived from the direct expenditures by the Operators under Alternative A 

would be comparable to those under the Proposed Action, totaling about $223.3 million during the 

development phase. Sales and use tax revenues derived from consumer expenditures would be slightly 

higher under Alternative A than under the Proposed Action, due to the higher level of employment during 

the development phase; however, estimates of the differences were not prepared for this analysis. 

Social Effects 

Social effects of Alternative A would be comparable to those associated with the Proposed Action. 

Environmental Justice 

No disproportionately high and adverse human health or environmental effects on minority or lowincome populations would be anticipated under Alternative A. 

4.15.2.4 Alternative B: Enhanced Resource Protection 

Employment 

Like the Proposed Action, Alternative B assumes a total of 8,950 wells drilled over a 15-year period, but 

assumes a 20 percent increase in the number of directionally drilled wells located on federal lands. For 

purposes of this assessment the shifts in projected long-term gas, condensate and water production would 

be the same as under the Proposed Action. Total direct employment under Alternative B, including longterm production and transportation employment, would be slightly lower than for the Proposed Action. 

However, the differences would not be of such a magnitude as to materially alter the direct, indirect, and 

induced employment and income effects from those anticipated under the Proposed Action. 

Consequently, the profile of employment growth and subsequent declines shown for the Proposed Action 

in Figure 4.15-6 reasonably characterizes the impacts on local employment of Alternative B. 

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Population 

Projected population growth under Alternative B, like the foreseeable effects on employment and income, 

would be similar but slightly lower than those under the Proposed Action. The majority of the projectrelated incremental population in Sweetwater County would be expected to reside in Rock Springs and 

Wamsutter. In Carbon County, most of the incremental population would be anticipated to live in Rawlins 

and Baggs/LSRV. Any difference in population in communities would likely be negligible and not 

reflective of any specific feature of Alternative B. 

Other Socioeconomic Effects 

Project-related demands on temporary and long-term housing resources, community infrastructure and 

local government services, and public-school enrollment under Alternative B would be comparable to 

those under the Proposed Action. 

Fiscal Effects 

Alternative B includes the same number of wells as the Proposed Action, both in total and on an annual 

basis, but more of the wells on federal lands would be drilled on multi-well pads. The projected 

production is also equivalent to that under the Proposed Action. Consequently, projected revenues from 

state severance taxes, FMR, state mineral royalties, and gross products/ad valorem taxes would be 

comparable to those under the Proposed Action: approximately $9.4 billion over the life of the field (see 

Table 4.15-13 above). 

Sales and use tax revenues derived from the direct expenditures by the Operators under Alternative B 

would be comparable to those under the Proposed Action, totaling about $223.3 million during the 

development phase. Sales and use tax revenues derived from consumer expenditures would be slightly 

lower under Alternative B than under the Proposed Action, due to the lower level of employment during 

the development phase; however, these differences would be minimal and estimates of the differences 

were not prepared for this analysis. 

Social Effects 

Generally, social effects of Alternative B would be comparable to those associated with the Proposed 

Action. However, the additional protections afforded by Alternative B for areas that are considered 

sensitive such as the sage-grouse lek complex southeast of Creston, the small portion of the Red Lake 

Dunes Citizens’ Proposed Wilderness that extends into the northwestern part of the project area, and the 

Chain Lakes WHMA would reduce concern for the environmental effects on those areas. 

Similarly, the additional resource protections provided by Alternative B (Section 2.2.3) would result in a 

reduction of impacts to forage and grazing activities and correspondingly reduce impacts to ranchers and 

grazing permittees as compared to the Proposed Action. 

Environmental Justice 

No disproportionately high and adverse human health or environmental effects on minority or lowincome populations would be anticipated under Alternative B. 

4.15.2.5 Alternative C: Surface Disturbance Cap 

Employment 

Like the Proposed Action, Alternative C assumes a total of 8,950 wells drilled over a 15-year period, but 

assumes a 50-percent increase in directional drilling of wells located on federal lands. Projected long-term 

gas, condensate, and water production would be the same as under the Proposed Action. Total direct 

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employment under Alternative C, including long-term production and transportation employment, would 

be lower than for the Proposed Action. However, the differences would not materially alter the direct, 

indirect, and induced employment and income effects from those anticipated under the Proposed Action. 

Consequently, the profile of employment growth and subsequent declines shown for the Proposed Action 

in Figure 4.15-6 reasonably characterizes the impacts on local employment of Alternative C. 

Population 

Projected population growth under Alternative C, like the foreseeable effects on employment and income, 

would be similar to but somewhat lower than those anticipated under the Proposed Action. 

Other Socioeconomic Effects 

Project-related demands on temporary and long-term housing resources, community infrastructure and 

local government services, and public-school enrollment under Alternative C would be comparable to but 

somewhat lower than those under the Proposed Action. 

Fiscal Effects 

Alternative C includes the same number of wells as the Proposed Action, both in total and on an annual 

basis, but more of the wells on federal lands would be drilled on multi-well pads. The projected 

production would also be equivalent to that under the Proposed Action. Consequently, projected revenues 

from state severance taxes, FMR, state mineral royalties, and gross products/ad valorem taxes would be 

comparable to those under the Proposed Action: approximately $9.4 billion over the life of the field (see 

Table 4.15-13 above). 

Sales and use tax revenues derived from direct expenditures by the Operators under Alternative C would 

be comparable to those under the Proposed Action, totaling about $223.3 million during the development 

phase. Sales and use tax revenues derived from consumer expenditures would be somewhat lower under 

Alternative C than under the Proposed Action, due to the lower level of employment during the 

development phase; however, the difference is anticipated to be small and estimates of the differences 

were not prepared for this analysis. 

Social Effects 

Social effects of Alternative C would be comparable to those associated with the Proposed Action. 

Environmental Justice 

No disproportionately high and adverse human health or environmental effects on minority or lowincome populations would be anticipated under Alternative C. 

4.15.2.6 Alternative D: Directional Drilling 

Employment 

Like the Proposed Action, Alternative D assumes a total of 8,950 new wells drilled but with all future 

natural gas wells on federal mineral estate to be drilled directionally from multi-well pads. Projected 

annual and long-term gas, condensate, and water production would be the same as under the Proposed 

Action (see Figure 4.15-3). Based on differences in the lower average overall labor requirements between 

vertical wells on single wells pads and those for directionally drilled wells on multi-well pads, on a per 

well basis, total direct employment under Alternative D, including long-term production and 

transportation employment, would be 5 to 10 percent lower than for the Proposed Action. However, the 

differences would not materially alter the direct, indirect and induced employment and income effects 

from those anticipated under the Proposed Action. Consequently, the profile of employment growth and 

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subsequent declines shown for the Proposed Action in Figure 4.15-6 reasonably characterizes the impacts 

on local employment of Alternative D. 

0.0 

0.1 

0.2 

0.3 

0.4 

0.5 

0.6 

0.7 

0.8 

Yr 1 Yr 8 Yr 15 Yr 22 Yr 29 Yr 36 Yr 43 

Annual Gas Production (mmcf) 

Alternative D 

Proposed Action 

Figure 4.15-13. Projected annual natural gas production (MMcf), Alternative D and Proposed Action 

Population 

Projected population growth under Alternative D, like the foreseeable effects on employment and income, 

would mirror those under the Proposed Action—but with about 300 fewer residents at the peak. The 

majority of the project-related incremental population in Sweetwater County would be expected to reside 

in Rock Springs and Wamsutter. In Carbon County, most of the incremental population would be 

anticipated to live in Rawlins and Baggs/the Little Snake River Valley. Any difference in population in 

communities would likely be negligible and not reflective of any specific feature of Alternative D. 

Alternative D would also result in lower initial influx of temporary non-resident workers during the initial 

years of implementation but also lower out-migration following the completion of new well development. 

Other Socioeconomic Effects 

The relatively minor differences in community population between Alternative D and the Proposed 

Action would result in minor differences in housing demand, demand for community infrastructure and 

local government services, and increases in public-school enrollment. Rock Springs and Rawlins would 

likely experience a somewhat smaller influx of temporary workers than under the Proposed Action, the 

difference resulting in a corresponding lesser decrease for services associated with the predominantly 

working-age-male demographics of that workforce. 

Fiscal Effects 

Alternative D includes the same number of wells as the Proposed Action, both in total and on an annual 

basis, but more of the wells on federal lands would be drilled on multi-well pads. The projected 

production is also equivalent to that under the Proposed Action. Consequently, projected revenues from 

state severance taxes, FMR, state mineral royalties, and gross products/ad valorem taxes under 

Alternative D would be comparable to those under the Proposed Action: approximately $9.4 billion over 

the life of the field (see Table 4.15-13 above). 

Sales and use tax revenues derived from the direct expenditures by the Operators under Alternative D 

would be comparable to those under the Proposed Action, totaling about $223.3 million during the 

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development phase. Sales and use tax revenues derived from consumer expenditures would be slightly 

lower under Alternative D than under the Proposed Action, due to the lower level of temporary 

employment during the development phase; however, estimates of the differences were not prepared for 

this analysis. 

4.15.2.7 Alternative E: No Action 

At year-end 2010 there were an estimated 3,486 producing wells in the project area. For this analysis, the 

No Action Alternative assumes that no additional wells would be drilled in the project area beyond those 

drilled before the issuance of the ROD for the EIS. Assuming the cessation of drilling in 2012, production 

would peak at approximately 270 Bcf per year, less than 40 percent of the peak under the Proposed 

Action, and then begin an extended period of decline (see Figure 4.15-14). Total remaining production 

from producing wells under No Action is estimated at about 3.2 Tcf of gas and 43 million barrels of oil 

condensates. 

0 

100 

200 

300 

400 

500 

600 

700 

800 

Yr 0 Yr 2 Yr 4 Yr 6 Yr 8 Yr 10 Yr 12 Yr 14 Yr 16 Yr 18 Yr 20 

Annual Gas Production (Bcf) 

Figure 4.15-14. Projected annual natural gas production under the No Action Alternative 

Sources: SDLLC & BCLLC based on USBLM Wyoming RMG production estimates 

Employment 

Implementation of the No Action alternative would reduce an important source of economic stimulus in 

the regional economy as drilling and field development in the CD-C area would come to a halt in 2012. 

Thereafter, drilling-and-completion-related employment would rapidly decline (Figure 4.15-15). Longterm production and transportation employment would also be lower under the No Action as compared to 

the Proposed Action, due to the lower volumes of gas, condensate, and water production.37 The loss of 

direct onsite and off-site drilling and field-development employment, along with the lower production and 

transportation jobs relative to the Proposed Action, would ripple through the economy, reducing the 

number of indirect and induced jobs supported by activity in the project area. The magnitude of the 

eventual job losses would grow over time. 

37 Current levels of direct onsite and off-site development employment associated with development are assumed to cease at the 

same time as the completion of drilling under the No Action. 

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(6.0) 

(4.0) 

(2.0) 

-

2.0 

4.0 

6.0 

Yr 1 Yr 3 Yr 5 Yr 7 Yr 9 Yr 11 Yr 13

Incremental Employment (000s) 

Proposed Action 

No Action 

Figure 4.15-15. Incremental employment in Sweetwater and Carbon Counties, No Action and Proposed 

Action 

SDLLC & BCLLC based on CD-C Operators’ employment estimates and REMI model output. 

Projected population change under No Action would initially show a modest decline as temporary 

residents would account for most of the outflow. Over time, population declines would mount as the 

losses in temporary and long-term induced and production-related jobs and slower growth in populationrelated consumer demand affected resident households. Net population declines in the region would 

exceed an estimated 2,000 residents within 5 years and eventually total approximately 4,000 fewer 

residents (see Figure 4.15-16), assuming the absence of other economic activity that would provide 

employment for the displaced workers. The largest declines in resident and temporary populations would 

occur in Rock Springs, with the largest relative difference occurring in Wamsutter. 

(5,000) 

(4,000) 

(3,000) 

(2,000) 

(1,000) 

-

1,000 

2,000 

3,000 

4,000 

5,000 

Yr 1 Yr 3 Yr 5 Yr 7 Yr 9 Yr 11 Yr 13

Incremental Population 

Proposed Action 

No Action 

Figure 4.15-16. Incremental population change, No Action and Proposed Action 

SDLLC & BCLLC based on CD-C Operators’ employment estimates and REMI model output. 

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Housing, Community Infrastructure and Services 

Implementation of the No Action Alternative would result in substantially lower demand for long-term 

and temporary housing resources in communities near the project area. Following the completion of 

development, and depending on other energy-development activities occurring at the time, communities 

near the CD-C project area could see substantial increases in vacancies and lower real estate values and 

rental costs in both long-term and temporary housing under the No Action Alternative. 

Communities near the project area would experience moderating demand for most community facilities 

and services following implementation of the No Action Alternative. Some workforce and social service 

organizations may see temporary increases in the need to assist individuals and families affected by loss 

of employment. Over time, the trends in population change could result in excess capacity in some 

communities depending on the level of other energy-development activity. Future reductions in service 

demand would be relatively greatest in Wamsutter and Baggs/LSRV but would also extend to Rawlins 

and Rock Springs. 

Fiscal Effects 

The No Action Alternative assumes a halt to new oil and gas development in the project area following a 

ROD for the EIS. Cessation of activity would be followed by a steady decline in production volumes, 

with corresponding effects on sales of product and the associated public sector tax revenues. Total 

estimated incremental sales value of production from existing wells under the No Action is projected at 

$15.0 billion, approximately 29 percent of the $52.0 billion in aggregate sales value under the Proposed 

Action. Under No Action, peak annual market value of sales is projected at $1.38 billion in 2012. The 

rapidity of both the growth and decline of annual sales volume under the No Action Alternative contrasts 

markedly to that for the Proposed Action (Figures 4.15-2 above and 4.15-17 below). 

$0.0 

$0.2 

$0.4 

$0.6 

$0.8 

$1.0 

$1.2 

$1.4 

$1.6 

Yr 1 Yr 5 Yr 9 Yr 13 Yr 17 Yr 21 Yr 25 Yr 29 

Billions 

Figure 4.15-17. Projected annual value of gas and condensate production, No Action 

Source: SDLLC and BCLLC 

The lower total production under No Action, relative to the Proposed Action, would result in 

correspondingly lower royalty and tax generation. Total projected revenues from the defined sources are 

$2.5 billion (Table 4.15-16), nearly 73 percent lower than under the Proposed Action. Similar relative 

reductions characterize the differences in the other major public sector revenues as well. The differences 

reflect not just the lower projected production, but also the absence of FMR resulting from the lack of 

additional new wells on federal lands under the No Action Alternative. State mineral royalties from new 

wells and production on state lands would, however, be the same as under the Proposed Action. 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—SOCIOECONOMICS 

Table 4.15-16. Summary of projected taxes and public-sector royalties on gas and condensate 

production, No Action ($2010) 

Year 1–10 

Subtotal 

Year 11–20 

Subtotal 

Year 21–30 

Subtotal 

Life of Project 

Total (40+ yrs) 

Severance tax $624,280,000 $274,610,000 $131,910,000 $1,049,850,000 

Federal mineral royalties 0 0 0 0 

State mineral royalties 92,800,000 48,870,000 22,780,000 168,960,000 

Ad valorem tax, counties 1

 120,840,000 64,940,000 31,330,000 223,670,000 

Ad valorem tax, schools 1 448,550,000 241,040,000 116,280,000 830,190,000 

Sales and use taxes 156,610,000 66,660,000 n/a 223,270,000 

Total combined sources $1,443,080,000 $696,120,000 $302,300,000 $2,495,940,000 

1

 These allocations assume the locally generated taxes are retained by the school districts and not subject to transfer to the 

state under the “recapture” provisions of the Wyoming School Finance Act. 

Source: SDLLC and BCLLC. 

The lower total production under No Action, relative to the Proposed Action, would result in 

correspondingly lower royalty and tax generation, including FMR and state mineral royalties due to the 

lack of new wells completed on public lands. Not only would less revenue accrue to the Wyoming State 

Foundation program from distributions of the FMR, but the program would also receive less revenue 

from the statewide mandatory levy on gross products and the taxable real property associated with oil and 

gas development. 

Sales and use taxes would also be substantially lower under No Action than under the Proposed Action 

due to the lower value of taxable purchases by the Operators and lower consumer expenditures by 

workers and businesses supported indirectly by new development. 

Social Effects 

Social effects of the No Action Alternative would include increases in unemployment and reductions in 

income that would result 15 years sooner under the No Action than the Proposed Action. Widespread 

unemployment would trigger out-migration and some disruption of the social fabric in communities. 

Local residents who have benefited economically from continued development of the project area would 

likely be dissatisfied with the forgone opportunities. 

As development within the project area ceases and interim reclamation occurs, many of the adverse 

impacts to grazing permittees would begin to diminish. Over time, the use of grazing allotments in the 

most intensely developed portions of the project area could increase, benefiting ranchers in the region. 

Similarly, as development activities cease and interim reclamation occurs, some recreation users of public 

lands within the project area might return to the area. 

Environmental Justice 

No disproportionately high and adverse human health or environmental effects on minority or lowincome populations would be anticipated under the No Action Alternative. 

4.15.3 Impact Summary 

Each of the alternatives assessed in this EIS would result in substantial social and economic effects within 

the study area. Under the parameters and assumptions used for this assessment, the five action alternatives 

would generate similar effects with minor differences. Alternative A – 100 Percent Vertical Drilling 

would have slightly higher levels of employment, population, sales and use tax generation, and housing 

and public infrastructure and services demand than the Proposed Action; Alternative B – Enhanced 

Resource Protection, Alternative C – Surface Disturbance Cap, and Alternative D – Directional Drilling 

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would each have increasingly fewer effects on socioeconomic conditions. However, for broad assessment 

purposes the effects of the five action alternatives would be similar and are summarized together. 

The beneficial economic, social, and fiscal effects of the action alternatives would be foregone under the 

No Action Alternative. Instead, the added economic stimulus associated with drilling, development, and 

production would be replaced by increased unemployment, workforce outmigration, and a decline in 

public-sector revenues. Moreover, these effects would begin occurring soon after the issuance of the 

ROD, 15 years sooner than under the action alternatives. 

Each of the five action alternatives would generate over 1,000 incremental total onsite and off-site direct 

jobs during the fifth year of field development and about 1,400 and 1,600 total direct jobs in Years 10 and 

15, respectively. Direct employment would decline sharply following the completion of new well 

development, shedding nearly 1,200 total direct jobs by Year 20. At that time, five years after drilling and 

field development is scheduled to cease, total direct jobs would decrease to below 500. 

For the five action alternatives, total employment including direct, indirect, and induced jobs, would 

climb to a peak of around 4,000 jobs in Year 14 of development. It is important to note that these would 

be in addition to the existing level of project-area employment associated with average annual drilling of 

almost 300 wells and production of over 3,700 wells. Once drilling/field development is completed, 

regional employment would decrease by over 4,300 jobs, which would include not only the incremental 

jobs associated with drilling/field development under the Proposed Action but the currently existing 

drilling/field development-related jobs as well, hence the total job loss would be larger than the total 

incremental job gain associated with the action alternatives, even though a substantial number of 

production-related jobs would remain after drilling/field development ceases. 

Population increases and losses for all alternatives would closely follow employment gains and losses. 

Incremental population associated with the five action alternatives would increase over time to a peak of 

about 3,700 new residents and almost 1,000 temporary workers during Year 15 of development. Projectrelated population would fall to about 700 residents by Year 20, five years after drilling/field development 

ceases. 

Project-related population under No Action would decline rapidly upon issuance of the ROD resulting in 

population outmigration in both Sweetwater and Carbon counties and the affected communities. 

The population associated with the five action alternatives would generate demand for additional longterm and temporary housing resources, increasing to an estimated total demand of over 1,500 long-term 

units and almost 1,000 temporary beds in Year 15 of development, and decreasing to about 250 long-term 

units and no temporary units during Year 20. Again, this substantial reduction in housing demand would 

be associated not only with the decrease in incremental demand associated with the action alternatives, 

but the decrease in demand from the population associated with current development and production 

employment in the project area as well. 

Implementation of the No Action Alternative would result in a substantial decrease in area housing 

demand compared to existing conditions. Depending on other energy-development activities occurring at 

the time of the issuance of the ROD, communities near the CD-C project area could see substantial 

vacancies in both long-term and temporary housing under the No Action Alternative. 

The substantial increase in population associated with the five action alternatives would generate 

corresponding demand for community infrastructure and services. Most communities within the study 

area have anticipated energy-related growth and have improved or are planning to improve major 

community infrastructure such as water, wastewater, solid-waste disposal systems, criminal detention 

facilities, and schools. Current or planned facilities should be adequate to accommodate the population 

associated with the action alternatives in the near term but may require expansion during the latter part of 

the 15-year drilling and field-development cycle, depending on the cumulative level of energy 

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development occurring at the time. Demand for community facilities would substantially diminish after 

the 15-year drilling/field-development cycle is completed. 

Many community-service providers would be required to add staff, equipment, and perhaps facilities to 

accommodate the population associated with the five action alternatives, particularly in the context of 

cumulative regional energy development. 

Under the No Action Alternative, current infrastructure and service demand associated with development 

in the CD-C project area would diminish substantially, perhaps resulting in excess capacity in some 

infrastructure and services, depending on the level of other energy development activity occurring at the 

time of the issuance of a ROD. Future reductions in service demand would be relatively greatest in 

Wamsutter and Baggs/LSRV but would also extend to Rawlins and Rock Springs. 

Substantial federal, state, and local government revenues would be generated by the natural gas and 

liquids production associated with each of the five action alternatives and by the capital investment 

associated with drilling/field development. Under the production and pricing assumptions used for this 

assessment, the action alternatives would generate about $3.8 billion ($2008) in FMR over the 40-year 

life of the project, and about $1.8 billion of that amount would accrue to the state. An estimated $530 

million in state mineral royalties would be generated by the action alternatives, and $3.1 billion in ad 

valorem and gross products taxes to various counties, special districts, school districts, and the Wyoming 

School Foundation Fund. Sales and use taxes associated with project-related investments would yield 

nearly $161 million in sales and use taxes at current rates: $115.8 million from the state’s 4.0 percent rate, 

$38.2 million in locally imposed taxes in Sweetwater County, and $6.7 million on sales in Carbon 

County. Projected distributions of the state’s sales and use tax receipts, based on the current statutorily 

established allocations would include $80.3 million to the general fund and $35.5 million to local 

governments. As noted above, sales and use tax revenues would be somewhat higher under Alternative A 

and somewhat lower under Alternatives B, C, and D. 

Oil and gas-related tax revenues would be much lower under the No Action Alternative than under any of 

the action alternatives, both in terms of annual receipts and total receipts over the life of the field. 

The lower total production under No Action relative to the action alternatives would result in 

correspondingly lower royalty and tax generation. Total projected revenues from the defined sources 

would be nearly 77 percent lower than under the Proposed Action. Similar relative reductions characterize 

the differences in the other major public-sector revenues as well. 

Not only would less revenue accrue to the Wyoming State Foundation program from distributions of the 

FMR, but the program would also receive less revenue from the statewide mandatory levy on gross 

products and the taxable real property associated with oil and gas development. 

Sales and use taxes would also be substantially lower under No Action than under the action alternatives 

due to the lower value of taxable purchases by the Operators and lower consumer expenditures by 

workers and businesses supported indirectly by new development. 

Social effects of the action alternatives would generally be similar to current effects in communities 

within the study area, which are both beneficial and adverse. Increases in certain types of crime and social 

problems and decreases in community cohesion could be associated with rapid population growth and 

large numbers of temporary workers in communities, depending on the concurrent level of energy 

development in the area. Conversely, increased employment opportunities, a generally robust economy, 

and increases in commercial and community infrastructure would be seen as beneficial to many residents. 

The fact that much of the project area is already developed and industrialized would diminish concern for 

further changes in most environmental amenities under the action alternatives. Given that substantial 

change in the recreation setting has already occurred, the relative change in recreation use associated with 

any further development would be small. The concern for development-related effects on areas that are 

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considered sensitive would also occur under all action alternatives, but would not occur under the No 

Action Alternative. 

The displacement of grazing permittees from the most intensively developed areas of the project area 

could occur under all alternatives; the risk of additional displacement would not occur under the No 

Action Alternative. 

No disproportionately high and adverse human-health or environmental effects on minority or lowincome populations would be anticipated under any of the action alternatives or the No Action 

Alternative. 

4.15.4 Unavoidable Adverse Impacts and Additional Mitigation Measures 

Most unavoidable adverse socioeconomic impacts of the Proposed Action and alternatives are associated 

with: the rapid and/or temporary influx of new workers, the need to provide housing and community 

services and facilities for the additional workforce and their families, and the decline in public revenues 

that would occur at the end of the project or with the implementation of the No Action alternative. The 

following mitigation measures should be implemented to reduce adverse socioeconomic effects and 

enhance the beneficial effects: 

	 To the extent practicable, the Operators should attempt to hire and train local workers from Carbon 

and Sweetwater counties. 

	 The Operators should acquire and require their contractors to acquire Carbon and Sweetwater 

County sales and use tax licenses and purchase all materials, equipment, and supplies to be used 

within the project area under these licenses so that proper attribution of sales and use tax payments 

can occur. 

	 The Operators and their major contractors should ensure that adequate temporary housing resources 

are available to accommodate their temporary drilling, field-development, and ancillary facility 

construction workforces. 

In order to allow local governments to effectively plan for the needed infrastructure and services to 

accommodate the workforce and population associated with this major development initiative, the 

Operators should meet annually with the BLM and representatives of local and state governments to 

discuss near-term and mid-term development plans. If events that would substantially accelerate or retard 

development in the project area become evident, the Operators should meet with the BLM and 

representatives of local and state governments to discuss the potential effects of such events. 

4.16 TRANSPORTATION 

This section assesses effects of the Proposed Action and other alternatives on the transportation system 

providing access to and within the CD-C project area, including federal and state highways, Carbon and 

Sweetwater county roads, BLM roads, and private roads. Environmental effects of new and improved 

roads within the project area are described in sections 3.3 Soils; 3.7 Invasive, Non-native Species; 3.8 

Wildlife; 3.11 Visual; 3.12 Recreation; and 4.18 Range Resources. 

4.16.1 Planning Documents and Criteria 

4.16.1.1 Rawlins RMP 

The Rawlins RMP (BLM 2008a) prescribes the following goal and objectives for transportation and 

access management: 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—TRANSPORTATION
 

Management Goal 

1.	 Develop and maintain a transportation management system to accommodate public demand for 

legal access through and across public land and to meet resource management needs and objectives 

(e.g., wildlife objectives). 

Management Objectives 

1.	 Maintain or expand, as determined necessary, existing access, including the right of access by a 

non-federal-land in-holder. 

2.	 Abandon or close redundant or unnecessary access roads; reclaim after consultation with local 

government and interested parties. 

3.	 Conduct transportation planning to manage existing and new access in a manner that ensures 

compatibility with resource values and management objectives. 

4.	 Incorporate existing state and county road systems into BLM transportation system to accurately
 

show existing access. Coordinate access issues with state and local governments.
 

4.16.1.2 Transportation Plan 

As noted in Section 3.16 Transportation and Access, an MOU between the BLM, WYDOT, Carbon 

and Sweetwater Counties and a number of the CD-C Operators established a transportation plan (TP) and 

transportation planning committee (TPC) for the Continental Divide portion of the project area. Upon the 

issuance of a ROD, the Creston portion of the project area will be brought into the TP and the Creston 

Operators will join the TPC as part of the federal permitting process. 

4.16.1.3 Impact Significance Criteria 

The following criteria are used to determine whether transportation impacts would be significant and 

represent a balance between public access and transportation safety: 

1.	 Substantial limitation on public access to travel within the project area. 

2.	 Substantial reduction in opportunity for acquisition of access easements and road development. 

3.	 Increases in traffic levels on the local public transportation system that would cause the level of 

service on the system to fall below acceptable levels, as defined by the responsible government
 

agency. 

4.16.2 Direct and Indirect Impacts 

Section 3.16 Transortation and Access describes the highway network providing access to the project 

area and the county, the BLM, and the private road network providing access within the project area. The 

CD-C project is an infill project; consequently, under all alternatives new roads would primarily be 

resource roads connecting the existing road network with new well pads, and ancillary facilities (e.g. 

gathering systems, compressor stations, and other associated infrastructure). 

The principal measure of transportation effects related to the alternatives would be changes in the number 

of vehicle trips required. Vehicle trips would be generated by drilling, completion, and ancillary facility 

construction; by production activities, including routine monitoring and maintenance; by hauling of 

produced water and liquids; and by periodic well workovers. Interim and final reclamation activities 

would also generate vehicle trips. 

For all alternatives, vehicle trips would originate from a variety of locations including Rock Springs, 

Rawlins, Wamsutter, Baggs, and locations outside the study area. Drilling rigs and some gas-field service 

and construction equipment would be transported to the project area and remain there for the duration of a 

particular contract or task. For the major Operators, drilling rigs would work on a year-round basis; in 

these cases, trips involving major pieces of equipment, such as rig moves, would occur primarily within 

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the project area. Similarly, most produced-water and liquids-collection trips are likely to occur entirely 

within the project area as produced-water disposal and liquids-transportation sites will be located within 

the project area. 

Many gas-field service firms serving the project area are presently located in Rock Springs, although 

some are located in Rawlins and a few are located in Baggs and the Little Snake River Valley (LSRV) 

area. BP has a major field-operations center just north of Wamsutter and several companies have 

established field offices and equipment lay-down and support yards in Wamsutter, which also houses 

many gas-field workers on both a temporary and longer-term basis. Devon Energy has a field office in 

Baggs to serve the Creston/Blue Gap field. There are two temporary living facilities located adjacent to 

WY 789 in the Dad area, and many gas-field workers reside in Rock Springs, Rawlins, and Baggs. 

Tables 4.16-1 and 4.16-2 display estimated per-well round-trips associated with typical drilling and 

production activities in the project area. Trip estimates were developed from information provided by the 

Operators, estimates from similar projects, and from information concerning anticipated per-well volumes 

of produced liquids and water provided by the BLM Wyoming’s Reservoir Management Group. The trip 

estimates are based on drilling and completion activities for typical wells, construction of gathering 

systems and well-site production facilities, performance of routine field operations and maintenance 

activities, and consideration of vendor and miscellaneous visits. 

Table 4.16-1. Per-well round-trip estimates: drilling and completion 

Activity 

Vertical Wells Multi-Well Pad (4 wells) 

Total Trucks1

 Total Trucks 

Pad/access road construction 35 21 45 28 

Mobilization / demobilization 107 73 161 97 

Drilling 251 174 980 704 

Completion 256 175 602 403 

Construction of production facilities, 

electrical and gathering lines 29 17 33 21 

Interim reclamation 10 6 15 9 

 Total Drilling 688 466 1,836 1,262 

1

 For this assessment, a “truck” is defined as any vehicle other than a passenger vehicle such as a pick-up, car, or van.
 

Sources: CD-C Operators; BCLLC
 

Table 4.16-1 displays trip estimates for single wells drilled vertically from an individual well pad and for 

directional wells drilled from multi-well pads, which are assumed to average four bores/pad. Directional 

wells drilled from multi-well pads generate reduced drilling, completion, and field-development traffic, 

on a per well basis, as compared to vertical wells on single-well pads. The reductions are principally in 

trips associated with well pad and access road construction, rig moves, completion, gathering and 

electrical system construction, and interim reclamation activities. 

Table 4.16-2. Estimated production traffic (round-trips) 

Activity All Wells 

Pumpers (pick-ups) Each well visited daily; each pumper can visit 15 wells/day 

Produced water & 

liquids haul trucks 

Trips are based on a BLM Reservoir Management Group decline curve for produced 

water and liquids assuming an average of 6,900 gallon haul trucks 

Workovers Each well every 15 years; 6 light truck and 8 heavy truck trips/well 

Sources: CD-C Operators; BCLLC 

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Tables 4.16-1 and 4.16-2 display traffic estimates in terms of round trips. The principal measure of traffic 

used elsewhere in the assessment is average annual daily traffic (AADT). In contrast to round trips, 

AADT represents one-way trips, i.e. AADT would count a round trip as two trips. 

Not all drilling and production trips would originate outside the project area. For each drilling and 

production activity, a certain number of trips would originate within the project area, including trips 

associated with some rig moves and other heavy equipment that would move from well pad to well pad 

without leaving the project area, commuting trips for some drilling and completion crews who reside in 

Wamsutter in motels and mobile-home/RV parks, and some trips associated with gas-field service 

companies whose offices and yards are located in Wamsutter. 

Under all action alternatives, construction and operations of additional compressor sites, a central pipeline 

compression facility, central gas-processing/stabilization facilities and high-pressure gas line would be 

required. Because the same number of wells would be developed under all action alternatives, the overall 

volume of traffic generated by these facilities is assumed to be the same, although the location of 

individual facilities and the timing of construction could differ based on the alternative. For Alternative E: 

No Action, no additional facilities are assumed to be required. 

4.16.2.1 Proposed Action 

This analysis assumes a total of 8,950 additional wells would be drilled over 15 years under the Proposed 

Action; an average of about 600 wells per year. The transportation assessment is based on the drilling 

schedule outlined in Section 3.5, Air Quality. Of the total wells, 42 percent are assumed to be directional 

wells drilled from multi-well pads averaging four bores/pad. The remaining 58 percent are assumed to be 

drilled vertically from single-well pads. 

Drilling and production in the project area during 2009 generated an estimated AADT of 1,525. Of that 

total, an estimated 1,060 trips traveled on highways providing access to the project area and on county, 

BLM, and private roads to a worksite within the project area. An estimated 465 trips were internal, both 

originating and terminating within the project area, traveling entirely on county, BLM, and private roads 

to reach a worksite. 

Figure 4.16-1 displays estimated Proposed Action-related AADT, including both internal and external 

trips by year through the 15-year drilling period and the first 15 years of full-field operations, based on 

the drilling schedule provided by the Operators. Transportation effects of drilling and production 

activities associated with the Proposed Action would build from an estimated 1,682 AADT in Year 1 to a 

peak of over 3,900 AADT in Years 13 and 14 of drilling. This would be in addition to the trips associated 

with ongoing production activities from existing wells, which are described under the No Action 

alternative (Section 4.16.2.6). This volume would diminish during the last year of drilling and for the 

remainder of the productive life of the project, as produced-water and liquids volumes decrease as the 

wells age. By Year 30 of the Proposed Action, an estimated 1,360 AADT would be generated daily within 

the project area. Table 4.16-1 provides estimates of per-well round trips for drilling and completion 

activities. Drilling-related trips could be higher or lower during any given year, depending on the actual 

number of wells drilled. Actual future drilling levels would vary in response to natural-gas demand and 

prices, drill rig and workforce availability, gas transmission pipeline capacity, weather, regulatory 

approvals, individual company development strategies, and other factors. Actual production-related trips 

would depend on the cumulative number of wells in production. 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—TRANSPORTATION
 

DRILLING 

PRODUCTION 

0

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

4,500

Year 1 Year 6 Year 11 Year 16 Year 21 Year 26

Projected AADT 

Figure 4.16-1. Drilling/field development AADT, Proposed Action 

Source: CD-C Operators, BCLLC 

Tables 4.16-3, 4.16-4, and 4.16-5 display estimated incremental highway AADT associated with Year 1, 

Year 10, and Year 20 of the Proposed Action. Year 1 AADT is contrasted with WYDOT 2009 AADT 

estimates for segments of highways providing access to the project area. It is important to note that 

WYDOT 2009 AADT estimates include traffic associated with the drilling of 244 new wells and 

production services for 3,783 wells within the project area during that year. 

Estimates of drilling-related traffic for Year 1 and Year 10 of the Proposed Action represent the increment 

over the 2009 drilling level, which are included in the WYDOT 2009 AADT and the forecast 2020 

AADT. Note that in Year 20 of the Proposed Action, project area-related traffic would be entirely 

operations related, as all drilling would have been completed under the assumptions used for this 

assessment. 

Project area drilling and production-related AADT were assigned to highway segments based on a 

combination of development-area access and likely locations of Operator offices and yards, natural gas 

field-service companies and vendor offices and yards, and temporary and long-term employee housing. 

Based on these origin and destination factors and a review of each drilling and production-related activity, 

it is assumed that about 40 percent of all project area-related trips would originate internally, from 

Wamsutter or elsewhere within the project area during the initial years of drilling. That percentage would 

decrease over time as production-related traffic increases. Beginning in Year 16, following the 

completion of drilling, an estimated 24 percent of all trips would be strictly internal, traveling exclusively 

on county, BLM and private roads. Internal trips would diminish to about seven percent by Year 30, due 

to reductions in produced water and liquids over time. 

Of trips that originate or terminate externally, 55 percent are assumed to be to or from Rock Springs; 25 

percent to/from Rawlins, 10 percent from Baggs/LSRV or at points along WY 789 and 10 percent from 

Wamsutter.38 Of the total trips traveling from Rawlins, 15 percent are assumed to originate at points to the 

38 Although Wamsutter is within the CD-C project area, external trips originating from Wamsutter are assumed to travel on I-80 to 

other destinations within the project area. 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—TRANSPORTATION 

north and travel US 287 through Rawlins during Year 1, 8 percent during Year 10, and 2 percent during 

Year 20 following the completion of drilling. 

Table 4.16-3.	 Projected AADT, highways providing access to the CD-C project area: Year 1, Proposed 

Action 

Highway Segment 

2009 WYDOT 

Estimated AADT 

Proposed Action 

Year 1 AADT 

% Increase 

over 2009 

All 

Vehicles Trucks 

All 

Vehicles Trucks 

All 

Vehicles Trucks 

I-80 

 Rawlins W. Urban Limits 13,078 6,495 158 75 1% 1% 

 Creston Junction 12,225 6,368 203 96 2% 2% 

 Continental Divide Int. 11,973 6,443 209 99 2% 2% 

 Wamsutter 12,014 6,458 503 238 4% 4% 

 Red Desert 11,563 6,332 413 195 4% 3% 

 Tipton 11,493 6,287 356 169 3% 3% 

 Table Rock 11,693 6,314 354 167 3% 3% 

 Rock Springs E. Urban Limits 1 1,678 6,498 348 165 3% 3% 

WY 789 

 Creston Junction 1,265 316 28 13 2% 1% 

 Jct CCR 700 West 1,801 427 28 13 2% 2% 

US 287 

 Rawlins N. Urban Limits 

(Bypass) 5,241 786 24 11 <1% 2% 

 Jct Rte 46 (Lamont/Bairoil) 2,303 620 24 11 1% 2% 

Jct = junction
 

Source: WYDOT 2009 VMB and 2020 and 2030 AADT projections; BCLLC calculations 

Under the assumptions used for this assessment, the highest concentration of project area-related traffic 

on I-80 would be at Wamsutter. As shown in Table 4.16-3, during Year 1 of the Proposed Action, when a 

total of 440 wells are assumed to be drilled, both total AADT and truck AADT on I-80 at Wamsutter 

would be an estimated 4 percent of 2009 WYDOT estimates for that location. Total AADT and truck 

AADT on WY 789 would be 1 to 2 percent of 2009 AADT. Total AADT would be less than 1 percent of 

2009 AADT at the bypass north of Rawlins; total and truck AADT would be 1 to 2 percent of 2009 

AADT elsewhere on US 287 during Year 1 of the Proposed Action. 

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Table 4.16-4.	 Projected AADT, highways providing access to the CD-C project area: Year 10, 

Proposed Action 

Highway Segment 

2020 WYDOT 

Projected AADT 

Proposed Action 

Year 10 AADT 

% Increase 

over 2020 

All 

Vehicles Trucks All Vehicles Trucks All Vehicles Trucks 

I-80 

 Rawlins W. Urban Limits 15,342 8,992 748 339 5% 4% 

 Creston Junction 14,915 8,740 960 436 6% 5% 

 Continental Divide Int. 14,880 8,750 985 447 7% 5% 

 Wamsutter 14,938 8,747 2,375 1,078 16% 12% 

 Red Desert 14,806 8,722 1949 885 13% 10% 

 Tipton 14,858 8,640 1683 764 11% 9% 

 Table Rock 15,054 8,782 1672 759 11% 9% 

 Rock Springs E. Urban Limits 16,715 9,374 1642 745 10% 8% 

WY 789 

 Creston Junction 1,501 377 132 60 9% 16% 

 Jct CCR 700 West 1,874 411 132 60 7% 15% 

US 287 

 Rawlins N. Urban Limits 

(bypass) 4,419 962 60 27 1% 3% 

 Jct Rte 46 (Lamont/Bairoil) 2,722 862 60 27 2% 3% 

Jct = junction
 

Source: WYDOT 2009 VMB and 2020 and 2030 AADT projections, BCLLC calculations.
 

During Year 10 of the Proposed Action (Table 4.16-4), a total of 738 wells are assumed to be drilled and 

6,240 Proposed Action-related wells would require production activities. Highway traffic estimates 

during Year 10 of the Proposed Action are contrasted with WYDOT forecasts of 2020 traffic on affected 

highways. Proposed Action-related AADT for all traffic on I-80 at Wamsutter would be a 16 percent 

increase over forecast 2020 AADT at that location and Proposed Action-related truck AADT would be 12 

percent. Total AADT on WY 789 at Creston Junction would be 9 percent of forecast 2020 AADT and 

truck AADT would be 16 percent. Proposed Action-related total AADT on US 287 would be 1 to 2 

percent of forecast 2020 AADT and truck AADT would be about 3 percent. 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—TRANSPORTATION 

Table 4.16-5.	 Projected AADT, highways providing access to the CD-C project area: Year 20, 

Proposed Action 

Highway Segment 

2030 WYDOT 

Projected AADT 

Proposed Action 

Year 20 AADT 

% Increase 

over 2030 

All 

Vehicles Trucks All Vehicles Trucks All Vehicles Trucks 

I-80 

 Rawlins W. Urban Limits 17,539 10,627 334 75 2% 1% 

 Creston Junction 17,142 10,320 429 98 3% 1% 

 Continental Divide Int. 17,130 10,354 440 99 3% 1% 

 Wamsutter 17,211 10,354 1,061 239 6% 2% 

 Red Desert 17,063 10,325 870 196 5% 2% 

 Tipton 17,132 10,224 752 170 4% 2% 

 Table Rock 17,365 10,43 747 168 4% 2% 

 Rock Springs E. Urban Limits 18,949 11,059 733 165 4% 1% 

WY 789 

 Creston Junction 1,731 426 59 13 3% 13% 

 Jct CCR 700 West 2,174 472 59 13 3% 3% 

US 287 

 Rawlins N. Urban Limits 

(bypass) 5,046 1,098 7 2 <1% <1% 

 Jct Rte 46 (Lamont/Bairoil) 3,000 978 7 2 <1% <1% 

During Year 20 of the Proposed Action, no new drilling would occur but 8,950 wells would require 

production-related activities. Highway traffic estimates during Year 20 of the Proposed Action are 

contrasted with WYDOT forecasts of 2030 traffic Proposed Action-related total AADT on I-80 at 

Wamsutter would be six percent of WYDOT projected 2030 AADT at that location and truck traffic 

would be two percent. Total AADT on WY 789 at Creston Junction would be 3 percent of forecast 2030 

AADT and Proposed Action-related truck AADT would be 13 percent. Both total and truck AADT on US 

287 would be less than 1 percent of forecast WYDOT 2030 AADT on that highway. 

Traffic associated with the Proposed Action would be unlikely to result in a deterioration of the LOS on I80, except to perhaps accelerate the decrease from LOS A to LOS B at the Creston Junction intersection, 

given the relatively high forecasts for Proposed Action-related traffic at that intersection during drilling 

and field development. Similarly, the level of Proposed Action-related traffic on WY 789 from Creston 

Junction south to Baggs would be unlikely to result in a substantial deterioration in LOS but would 

certainly contribute to the LOS rating of C at the intersection with Carbon County Road 700 West during 

the drilling and field development period. The Proposed Action-related traffic on US 287/WY 220 north 

to Casper will contribute to the decrease in LOS from B to the forecast LOS C, but the relatively minor 

level of project-related traffic will play a small role in that decrease in LOS. 

In addition to the drilling and production-related traffic shown in the preceding table, a number of 

ancillary facilities would be required under the Proposed Action. Such facilities could include up to 10 

field compression facilities, a central pipeline compression facility, one central processing/stabilization 

plant, and up to 45 miles of high-pressure pipeline. Trip estimates for these facilities were not available 

from the Operators; consequently, estimates of similar facilities in other natural gas development areas 

were used to provide order-of-magnitude estimates for assessment purposes. Table 4.16.6 below 

summarizes the construction trip traffic associated with each of these facilities. 

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Table 4.16-6. Projected traffic effects on highways associated with ancillary facilities: Proposed Action 

Facility Type Duration of 

construction 

Light-duty 

vehicle trips Truck trips Total trips Approximate AADT 

Field compressors 

(up to 10 required) 

Several weeks per 

compressor 

152 / 

compressor 

facility 

24 / 

compressor 

facility 

176 / 

compressor 

facility 

< 1.0 

Pipeline 

compressors (1) Several months 760 120 880 5 

Central processing 

facility (1) Up to two years 27,200 12,700 39,900 110 

High-pressure 

pipeline (45 miles) -- 1,305 1,951 3,256 18 

Source: BCLLC. 

These facilities would be constructed at different locations and at different times during the drilling and 

field-development period; therefore, the construction trips would also occur during different periods. In 

addition to the construction traffic estimates contained in Table 4.16-6, these facilities would generate a 

low level of traffic during operations and most of those trips would involve light-duty vehicles. 

Because AADT is calculated on a 365-day/year basis, construction of each of these facilities, except the 

central gas-processing/stabilization facility, would result in minor increases in AADT. However, traffic 

on the specific access road to each facility and at intersections of highways and access roads could be 

substantial during the construction period, particularly during shift changes for construction workers. 

During these brief periods, the level of service ratings for these intersections could drop below current 

levels. As noted, once constructed, these facilities would generate relatively low volumes of daily traffic. 

The increases in traffic volumes associated with the Proposed Action could result in additional 

maintenance requirements on affected highway segments, particularly on WY 789 and on I-80 around the 

Wamsutter interchange during peak drilling years. The volume of over-height/over-width loads using I-80 

underpasses (described in Section 3.16.2) would continue to increase under the Proposed Action, 

requiring more frequent Wyoming Highway Patrol traffic-safety services, unless and until modifications 

in underpasses are completed. Given the substantial percentage increase in AADT associated with the 

Proposed Action, higher accident rates could be possible on the segments of highways providing access to 

the project area, especially during peak drilling years. 

County roads providing access within the project area would see substantial increases in use, particularly 

SCR 23S (Wamsutter-to-Crooks Gap Road South), CCR 701 (Wamsutter-to-Dad Road), and SCR 23N 

(Wamsutter-to-Crooks Gap Road North), which would provide access to the most densely developed 

portion of the project area. CCR 701 currently has the highest traffic volume of any road or highway in 

Carbon County, with the exception of I-80, and SCR 23 (north and south) is among the highest trafficvolume roads in Sweetwater County. The vast majority of traffic on these roads is industrial and is 

associated with project area gas-field activities. The Proposed Action would result in substantially 

accelerated maintenance requirements on these roads and likely require additional improvements to 

accommodate the increased volume of industrial traffic. 

Certain BLM and private roads providing access within the project area would also experience substantial 

increases in traffic associated with the development phase of the Proposed Action. Typically the 

Operators improve and maintain these roads through agreements with the BLM and private surface 

owners. Operators would also be required to secure right-of-way agreements with private landowners for 

use of private roads and BLM roads without right-of-way agreements. 

Based on the above, the state of Wyoming, Sweetwater and Carbon counties, and the BLM would all 

experience substantially higher road-improvement and maintenance requirements associated with the 

Proposed Action. Each of these entities would also receive substantial additional revenues from severance 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—TRANSPORTATION
 

taxes (in the case of the state), federal mineral royalties (in the case of the BLM, the state, and the 

counties) and from ad valorem property taxes (in the case of the counties39), on natural gas production 

associated with the Proposed Action, which could be used to help fund Proposed Action-related 

improvements and maintenance requirements. 

Continued implementation of the CD-C TP and TPC process would result in a coordinated approach to 

road use, development, maintenance, and reclamation; to the extent possible considering the high level of 

development and associated traffic, it would also reduce transportation effects. 

4.16.2.2 Alternative A: 100-Percent Vertical Drilling 

Alternative A assumes the same overall drilling schedule as the Proposed Action, but assumes all wells 

would be drilled vertically from single-well pads. The trip-generation factors used for Alternative A are 

the same factors used for vertical wells in the Proposed Action (see Vertical Wells columns in Table 

4.16-1). 

Figure 4.16-2 compares total AADT for the Proposed Action and Alternative A. Alternative A would 

result in an estimated total AADT of 1,935 during Year 1, 15 percent higher than the estimated total 

AADT for the Proposed Action during Year 1. During Year 10, Alternative A would generate an 

estimated AADT of 4,217, 10 percent greater than the Proposed Action. The smaller percentage is the 

result of the larger proportion of operations-related traffic to total traffic in that year (the level of 

operations traffic would be the same under either alternative). After Year 15, when drilling is assumed to 

be completed under both alternatives, the estimated average number of round trips would be the same. 

The higher level of traffic associated with Alternative A would generate correspondingly higher levels of 

traffic on federal and state highways providing access to the project area. However, incremental AADT 

associated with Alternative A would generate no more than 1 to 2 percent increases in AADT on any 

highway segment during the first 15 years as compared to the Proposed Action. 

Under Alternative A, the increases in AADT on highways providing access to the project area associated 

with construction and operations of additional compressor sites, a central pipeline compression facility, 

two or more central gas processing/stabilization facilities and 45 miles of high-pressure gas line would be 

the same as under the Proposed Action. 

The higher traffic volumes associated with Alternative A would result in correspondingly higher 

maintenance requirements on affected highway segments as compared to the Proposed Action and 

generate the potential for higher accident rates on the segments of highways providing access to the 

project area. 

County roads providing access within the project area would experience higher levels of traffic under the 

drilling and field-development phase of Alternative A compared to the Proposed Action and 

correspondingly higher maintenance requirements. 

BLM and private roads providing access within the project area would also experience higher increases in 

traffic associated with the Proposed Action. As with the Proposed Action, the Operators would improve 

and maintain these roads through agreements with the BLM and private surface owners. 

Although WYDOT and Sweetwater and Carbon counties would experience higher road maintenance costs 

under Alternative A compared to the Proposed Action, natural gas production would likely be the same 

under both alternatives; consequently, the state and counties would receive the same revenues under both 

alternatives but be required to fund somewhat higher highway and road maintenance costs under 

Alternative A than under the Proposed Action. 

39 Sweetwater County has a dedicated mill levy for road and bridge funding; Carbon County does not. 

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0 

500 

1,000 

1,500 

2,000 

2,500 

3,000 

3,500 

4,000 

4,500 

Proposed Action Alt A 

Figure 4.16-2. Total project-related AADT: Alternative A and Proposed Action 

As with the Proposed Action, continued implementation of the CD-C TP and TPC process would result in 

a coordinated approach to road use, development, maintenance and reclamation and, to the extent possible 

considering the high level of development and associated traffic, reduce potential transportation effects. 

4.16.2.3 Alternative B: Enhanced Resource Protection Alternative 

Implementation of Alternative B would result in the same drilling schedule and number of wells as the 

Proposed Action. For the purposes of this assessment, it is assumed that implementation of the enhanced 

resource protection measures described in Section 2.2.3 would result in a 20 percent increase in 

directional drilling from multi-well pads on federal lands compared to the Proposed Action. This would 

result in 53 percent of all wells within the project area being drilled vertically from single well pads 

(compared to 58 percent for the Proposed Action) and 47 percent of all wells being drilled directionally 

from multi-well pads (compared to 42 percent for the Proposed Action). 

Figure 4.16-3 provides a comparison of total AADT for the Proposed Action and Alternative B. 

Alternative B would result in an overall reduction of 1 to 2 percent in total AADT during the 15-year 

drilling period compared to the Proposed Action. However, at a site-specific level, drilling four 

directional wells on a multi-well pad would require approximately 33 percent fewer trips than drilling 

four vertical wells on individual pads. Consequently, reductions in traffic at specific well-site locations 

could be substantial under Alternative B as compared to the Proposed Action. 

After drilling is completed, Alternative B and Proposed Action AADT would be the same because the 

same number of wells would require production-related activities. Traffic associated with construction of 

ancillary facilities under Alternative B would be similar to that associated with the Proposed Action. 

Highway and road maintenance and improvement requirements would be similar for both alternatives, as 

would the potential for increases in accidents. Similar levels of tax and royalty revenues would accrue to 

state and local governments under both alternatives. 

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0

500

1000

1500

2000

2500

3000

3500

4000

Proposed Action Alt B 

Figure 4.16-3. Total project-related AADT: Alternative B and Proposed Action 

4.16.2.4 Alternative C: Surface Disturbance Cap – High and Low Density Development Areas 

Implementation of Alternative C would result in the same drilling schedule and number of wells as the 

Proposed Action. For the purposes of this assessment, it is assumed that implementation of the 60-acre 

surface disturbance cap in high-density natural gas development areas and the 30-acre disturbance cap 

elsewhere in the project area would result in a 50-percent increase in directional drilling from multi-well 

pads on federal lands. This would result in 46 percent of all wells within the project area being drilled 

vertically from single well pads (compared to 58 percent for the Proposed Action) and 54 percent of all 

wells being drilled directionally from multi-well pads (compared to 42 percent for the Proposed Action). 

Figure 4.16-4 compares total AADT for the Proposed Action and Alternative C. Implementation of 

Alternative C would result in a reduction of 3 to 4 percent in total AADT during Years 1 through 13 of 

the 15-year drilling period compared to the Proposed Action; AADT would be the same for the two 

alternatives after drilling is completed. As with all alternatives, at a site-specific level, drilling four 

directional wells on a multi-well pad would require an estimated 33 percent fewer trips than drilling four 

vertical wells on individual pads. 

After drilling is completed, Alternative C and Proposed Action AADT would be the same because the 

same number of wells would require production-related activities. Traffic associated with construction of 

ancillary facilities under Alternative C would be similar to that associated with the Proposed Action. 

Highway and road maintenance and improvement requirements would be similar for both alternatives, as 

would the potential for increases in accidents. Similar levels of tax and royalty revenues would accrue to 

state and local governments under both alternatives. 

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0 

500 

1000 

1500 

2000 

2500 

3000 

3500 

4000 

Proposed Action Alt C 

Figure 4.16-4. Total project-related AADT: Alternative C and Proposed Action 

4.16.2.5 Alternative D: Directional Drilling 

For the purpose of this assessment, it is assumed that requiring all wells on federal lands to be drilled on 

multi-well pads would result in a 74-percent increase in directional drilling from multi-well pads on 

federal lands. This would result in a total of 27 percent of all wells within the project area being drilled 

vertically from single well pads (compared to 58 percent for the Proposed Action) and 74 percent of all 

wells being drilled directionally from multi-well pads (compared to 42 percent for the Proposed Action). 

Figure 4.16-5 provides a comparison of total AADT for the Proposed Action and Alternative D. 

Implementation of Alternative D would result in a reduction of 3 to 11 percent in total AADT during the 

15-year drilling period compared to the Proposed Action. These reductions would result from the reduced 

number of trips required for location construction, rig mobilization and demobilization, and other drilling 

and completion activities that could be performed for multiple wells on one well pad. During project 

operations, AADT would be about the same as that associated with the Proposed Action. 

After drilling is completed, Alternative D and Proposed Action AADT would be similar because the same 

number of wells would require production-related activities. Traffic associated with construction of 

ancillary facilities under Alternative D would be similar to that associated with the Proposed Action 

although the timing and location of facilities construction could differ. 

Highway and road maintenance and improvement requirements would be similar for both alternatives, as 

would the potential for increases in accidents. Similar levels of tax and royalty revenues would accrue to 

state and local governments under both alternatives. 

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0 

500 

1000 

1500 

2000 

2500 

3000 

3500 

4000 

4500 

Proposed Action Alt D 

Figure 4.16-5. Total project-related AADT: Alternative D and Proposed Action 

4.16.2.6 Alternative E: No Action 

Under the No Action alternative it is assumed that drilling activities would cease upon issuance of a ROD 

for the EIS. The termination of drilling within the CD-C project area would result in a reduction of traffic 

on area highways and roadways; during 2009 an estimated AADT of 726 was associated with drilling and 

completion activities within the project area. Production activities for existing wells would continue under 

the No Action alternative; it is estimated that an AADT of 798 was associated with production activities 

within the project area during 2009. Production-related AADT would be somewhat higher initially to 

account for additional wells drilled prior to the issuance of a ROD, but begin to decline thereafter as 

produced water and liquids volumes decline and wells come off-line as the field matures. 

The reduction in traffic associated with the No Action alternative would result in substantially lower wear 

and tear on area highways and on county, BLM, and private roads as compared to any of the action 

alternatives. Conversely, state and county governments would receive substantially fewer revenues to 

perform road maintenance activities. Given the substantially lower volumes of traffic, the potential for 

project-related accidents would be substantially lower under the No Action alterative. 

4.16.3 Impact Summary 

Figure 4.16-6 contrasts estimated total AADT for the Proposed Action with each of the four action 

alternatives. 

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0 

500 

1000 

1500 

2000 

2500 

3000 

3500 

4000 

4500 

Proposed Action Alt A Alt B Alt C Alt D 

Figure 4.16-6. AADT, all action alternatives 

Each action alternative would result in increases in traffic associated with drilling and production 

activities. Based on the assumptions associated with each alternative, the pattern of traffic increases 

would be similar for all alternatives. Differences in the magnitude of traffic increases on affected 

highways and roads would result from differences in the ratio of directional wells drilled on multi-well 

pads to wells drilled horizontally on single-well pads. Additionally, the pace of drilling would be a factor 

under Alternative D. 

In addition to the traffic associated with drilling and production, each action alternative would result in 

similar temporary increases in AADT on federal and state highways resulting from construction of 

ancillary facilities such as compressor sites, a central pipeline compression facility, two or more central 

gas-processing/stabilization facilities, and a high-pressure gas line. 

All action alternatives would accelerate highway maintenance requirements on county, BLM, and private 

roads. The timing and level of improvements and maintenance requirements would be driven by the 

magnitude of traffic increases on specific highways and roads. 

All action alternatives would generate similar amounts of revenue that could be used to fund highway and 

road-maintenance needs. 

Highway and road-maintenance requirements would be substantially less under the No Action alternative 

than under any action alternative. The amount of production-related tax and royalty revenues to fund 

maintenance requirements would correspondingly decrease as production diminishes and wells cease 

production at a more rapid pace than under the action alternatives. 

4.16.4 Unavoidable Adverse Impacts and Additional Mitigation Measures 

Most unavoidable adverse transportation impacts of the Proposed Action and alternatives are associated 

with increases in the number of vehicle trips on the network of roads and highways in the project area and 

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the consequent need to manage and maintain that network. An important component for reduction of 

those impacts for all action alternatives would be continued active participation in the CD-C TP and TPC 

process. For all alternatives, the substantial increase in industrial traffic would require a sustained and 

coordinated transportation-planning and road-maintenance effort. For Alternative E, No Action, roadabandonment and reclamation planning would be required sooner than under the action alternatives. 

4.17 NOISE 

4.17.1 Introduction 

Noise anticipated from the Proposed Action and all alternatives would include that which currently occurs 

within the CD-C project area as a result of gas-compression stations, livestock grazing operations, wind, 

well-workover operations, and traffic along area access roads, state highways, and I-80. Additional noise 

would be generated by well site and access road construction, drilling and completion, pipeline 

construction, and surface-disturbing reclamation operations. Frequent strong winds would add to ambient 

noise levels. The EPA guideline of 55 decibels (dBA) represents a level at which an activity would have 

no effect on receptors in the environment; the sounds would not be noticeable to the human ear. Emerging 

research relative to the impact of noise on wildlife, specifically greater sage-grouse and mountain plover, 

indicates this level of noise or the 49-dBA level (10 dBA over background) commonly found in BLM 

documents may not be sufficiently protective (Blickley and Patricelli undated, Blickley and Patricelli 

2010). The Rawlins RMP does not contain specific noise limitations or reduction/mitigation 

requirements; rather, the RMP manages noise impacts through performance-based project design or 

mitigation. In Appendix 15 to the RMP (Best Management Practices) there is a general statement 

requesting consideration of “noise reduction techniques and designs” to benefit wildlife in general and the 

greater sage-grouse in particular. 

Blickley and Patricelli (2010) express concern that, “Other acute impacts of noise, such as masking and 

behavioral disruption, occur over a much larger area. Masking occurs when the perception of a sound is 

affected by the presence of background noise, with high levels of background noise decreasing the 

perception of a sound.One possible consequence of masking is a decrease in the efficacy of acoustic 

communication. Many animals use acoustic signals to attract and retain mates, settle territorial disputes, 

promote social bonding, and alert other individuals to predators. Disruption of communication can, 

therefore, have dramatic impacts on survival and reproduction,” and “In addition to the acute effects of 

noise, animals may suffer chronic effects, including elevated stress levels and associated physiological 

responses. Over the short term, chronic stress can result in elevated heart rate.Longer-term stress can be 

associated with the ability to resist disease, survive, and successfully reproduce.” 

Appendix 16 of the Rawlins RMP (Mountain Plover Guidelines) provides for operations setbacks from 

identified nesting habitat, as follows: “To protect the identified mountain plover-occupied habitat, the 

proposed facility will be moved one-half mile from the identified occupied habitat.” Blickley and 

Patricelli (2010) found through their research of selected compressor stations in the Powder River Basin 

that “stipulations limiting the development of compressor stations within 1⁄2 mile of nesting sites are likely 

to prevent masking of the mountain plover vocalizations analyzed.” 

Refer to Wildlife (Section 4.8) and Special Status Species (Section 4.9) for evaluations of the 

performance standards and their effectiveness relative to the project area. 

4.17.2 Management Objectives and Impact Significance Criteria 

The Rawlins RMP (BLM 2008a) does not provide management objectives specific to noise. The 

following criterion was used to assess the significance of noise impacts related to this project: 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—NOISE 

1.	 Long-term activities that would exceed the federal 55-dBA maximum guideline for noise at either 

human- or animal-sensitive locations. 

Impact significance criteria for noise relative to wildlife and special status species can be found in 

Sections 4.8 and 4.9, respectively. 

4.17.3 Direct and Indirect Impacts 

4.17.3.1 Proposed Action 

Direct impacts of the Proposed Action would include increased noise levels from the drilling, completion, 

and production of an additional 8,950 wells, of which 500 may be CBNG. Operators anticipate drilling up 

to 600 wells per year with up to 25 rigs running at any one time for up to 15 years; 42 percent of the wells 

could be directionally drilled. Related activities would include construction of associated infrastructure 

including access roads, power lines, and gas/water/condensate pipelines, as well as the reclamation of 

disturbed areas. 

Construction and drilling operations would take place at each well site resulting in an increase in noise 

when compared to the natural background condition of 30 to 50 dBA. Construction, drilling, and 

completion activities related to the drilling of conventional wells may last from 30 to 60 days. Wells 

drilled directionally may take slightly longer to drill and complete compared to vertical conventional 

wells. Directional wells may also require a larger rig with larger engines. Directional pad drilling usually 

involves several wells drilled from the same location, lengthening the period of disturbance per location. 

If 3,760 wells were drilled directionally, the greater number of days needed for drilling and completion 

activities would increase well-development noise/activity substantially, compared to vertical drilling. 

However, directional drilling would result in fewer well pads and access roads being built in the project 

area and would require a reduced number of rigs to accomplish the development within the estimated 10- 

to 15-year period. Fewer semi-truck loads of equipment would be brought to each site, resulting in 

reduced overall traffic noise. The shallower CBNG wells are expected to take up to 20 days for drilling 

and completion. 

Equipment and operational noise would be generated during these activities from a variety of sources 

including engines, equipment impact, and well-flaring. The large rigs used for drilling conventional wells 

are significantly louder than the lower-horsepower (hp) rated small drilling rigs used for developing 

CBNG. It has been determined that drilling and flaring operations produce the loudest project-related 

noise. In the Jonah field, noise from drilling operations was measured as 77.5 dBA onsite and 50.1 dBA 

at 0.25 miles (BLM 2006b). Based on this information, drilling operations should not exceed the 

significance threshold for impacting sage-grouse leks—a sensitive receptor—as long as the lek and nest 

protection buffers are observed. This is consistent with the findings of the 2009 PAPA Noise Study (KC 

Harvey 2009) which evaluated noise at various lek sites within the natural gas field. Flaring operations at 

the Jonah field were measured at 97.9 dBA on site and 66.3 dBA at 0.25 miles. The use of flowback 

separators decreased flaring noise to 63.7 dBA on site. Holloran (2005) suggests that heavily traveled 

main haul-roads located within 3 miles of greater sage-grouse leks may negatively impact male lek 

attendance. While Holloran (2005) does not provide information regarding the vehicle type(s), anecdotal 

information (Holloran pers. com. 2003) indicated a steady stream of large diesel semi-rigs such as water 

and fuel tankers, completion equipment haul trucks, and drilling equipment as the traffic generating noise 

and disturbance impacts to sage-grouse. Directional pad drilling would result in locally more intense 

noise generation but would result in fewer well pads and access roads being built in the project area. In 

addition, directional pad drilling would result in fewer total semi-truck loads of equipment going into the 

field over the life of the project. 

During the production phase of field operations, noise sources are generally less intense or of very short 

duration. These activities include occasional well workovers, routine site visitation by company personnel 

(“pumpers” and technicians) and road-maintenance equipment. Produced-water and condensate hauling, 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—NOISE 

compressor stations, and well-site compression are generally louder and frequent or continual sources of 

noise. 

Vehicle traffic associated with production is typically limited to pickup trucks and occasional workover 

rigs. Wells producing water and condensate are regularly visited by haul tanker trucks, which transport 

these fluids to disposal facilities and sales points unless connected to gathering pipeline systems. In the 

absence of gathering systems, the greater the volume of fluid produced, the more frequent the tanker 

visits. 

Noise resulting from compressor stations or well-site compression would continue for as long as gas 

production, gathering, and transmission occur within the field or from a particular well. The number, size, 

and location of field compressors would change over the life of the field depending on the volume of gas 

produced, the size of the lines, and the volume and pressure of gas within the major transmission lines. 

Project Operators anticipate the need for 10 additional compressor stations in the project area including 

one large central pipeline compression facility. Operators also anticipate the need to enlarge some of the 

existing compression infrastructure. 

The need for well-site compression is dependent on the characteristics of the specific well and gas-line 

pressures. An unknown number of wells would likely require well-site compression for some period of 

time during the life of the project. Well-site compression typically uses 125- to 200-hp two-stage 

compressors. 

Two or more central gas-processing/stabilization plants would also be required within the project area. 

The specifics of these anticipated facilities have not been determined and would be evaluated on a caseby-case basis by the BLM. 

Existing operations within the project area generate noise levels as indicated in Table 4.17-1. Operations 

that may result from the Proposed Action are expected to generate noise at the same level at a larger 

number of sources for the life of the project. 

Table 4.17-1. Typical noise measurements from common energy development-related sources in the 

CD-C project area1 

Description HP dBA dBC 

Two (2) Cat 3516 with noise wall 1,000 45 --

Two (2) Cat 3516 without noise wall 1,000 50 --

Two (2) Waukesha H24 and F18 compressor engines -- 75 --

Two (2) electric-driven compressors -- 65 --

One (1) Ajax Cooper 2802 250 51 --

One (1) Ajax Cooper 2803 compressor engine 400 52 --

Cat or Waukesha compressor engine 1,200 75 --

Cat or Waukesha with high-performance intake and exhaust silencers 1,200 70 --

One (1) Waukesha 5794LG compressor engine; fan end 1,000 91 95 

One Cat 3516 compressor engine; fan end, quiet fan 1,000 63 

One (1) Dehyd boiler 15 52 --

One (1) Cummins electric generator skid unit 1,000 69 --

Cat 3608 compressor engine w/ 2 heat exchangers -- 79 --

Disposal well pump building with electric motors inside -- 53 --

Cat 3608 compressor engine 1,000 58 --

Drill rig (Jonah Field) -- 69 

One (1) Ajax/Cooper compressor engine with weather cover 4,000 -- 76 

One (1) Champlin 242J-12 Ajax wellhead compressor -- 71 86 

1

Noise emission data – Levels at 100 ft. collected by Engineering Dynamics Incorporated. 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—NOISE 

Relative to the production life of a well, the construction, drilling, and completion phases of operations 

are short-term events lasting up to 60 days. However, when considered over the life of the Proposed 

Action, the increased noise levels resulting from drilling and completion activities at multiple sites within 

the project area would continue for up to 15 years, until the resource is fully developed. In addition to the 

noise related to field-development activities, noise could be expected from the continued production and 

maintenance of existing wells within the project area. Noise levels in the project area would also continue 

to be influenced as they are now by weather, occasional vehicle traffic, and aircraft overflights. 

At various times and at specific locations within the project area, noise levels associated with drilling, 

field-development, and operations activities would temporarily exceed the EPA-established baseline noise 

levels of 39 dBA for a “Farm in Valley” and the EPA-established threshold of 55 dBA, averaged over 24 

hours. Noise generated from these activities can be of an intensity and frequency that causes harm to 

human receptors. Field-development and production-related noise impacts would affect site workers who 

are subject to state and federal Occupational Health and Safety (OSHA) standards. OSHA mitigation 

standards for noise limits exposure as follows: an 8-hour time-weighted average of 85 dBA or a dose of 

50 percent are referred to as OSHA action levels [29 CFR 1910.95(c)(2)]. Occupational exposure to noise 

levels in excess of 85 dBA requires monitoring and mitigation, preferably by engineering means, to 

protect workers. Offsite worker impacts would be limited due to the lack of residential occupation and 

concentrated recreational activity within the development area. The small towns within the project area 

are generally located along I-80 and would continue to be impacted by the general noise of human 

activity, the vehicle and traffic noise generated along the interstate, and train movement along the 

railroad. Scattered, transitory activities such as livestock operations and recreation including hunting may 

be exposed to noise as they move past development activities and operating equipment. Temporary 

worker housing (man camps) located within the project area may be affected by noise generated by fielddevelopment activities but these impacts would generally be associated with specific operations and of 

limited duration. Noise can also modify animal behavior and habitat-use patterns such as the use of 

critical winter habitats or sage-grouse leks. 

Operational noise would be lessened with the implementation of remote telemetry, which can 

significantly reduce the number of site visits needed by operations personnel. A survey conducted in the 

Moxa field area (BLM 2007e) found that the use of telemetry (remote monitoring of wells) could reduce 

field visits by 50 percent. The use of electricity or natural gas as a fuel for onsite power generation, as 

opposed to the use of diesel fuel, also reduces noise levels. There would be situations when noisemitigation opportunities are limited by operational and engineering constraints. For example, CBNG 

production might be operated using diesel generators until water is removed and gas volumes are 

adequate to power pumping equipment. Natural gas wells may require artificial lift systems to facilitate 

production resulting in the need to use gas-lift, plunger-lift, down-hole pump, or other technology. This 

could include rod pumps or other noise-generating mechanisms. Depending on the fluid volumes 

produced, the installation of produced-water and condensate-gathering systems to transport these fluids to 

centralized facilities for disposal or sale could substantially reduce production-related noise compared to 

tanker-truck transportation. 

Noise from field-development and production activities can also be dampened or reduced with the use of 

mechanical muffler systems; the use of vegetative, constructed, or topographic screening; distance; and 

consideration of the direction of the noise source from the receptor. These methods serve to lessen the 

impact of noise on workers, residences, and sensitive wildlife species. Noise is also affected by 

environmental factors such as humidity, wind direction and speed, and air density. Consideration of the 

prevailing wind direction when siting noise-generating operations also serves to lessen the impact of noise 

on sensitive receptors. 

Indirect impacts of the Proposed Action include the continued production of the existing federal, fee, and 

state wells in the project area and the continuation of compression required to transport the gas produced 

in the field. Noise-control devices already in place would continue to provide mitigation. Directional 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—NOISE 

drilling of 3,760 wells would require an increase in the number of rigs needed to complete development 

within the proposed 10- to 15-year period due to the additional number of days needed for drilling and 

completion activities per well; alternatively, the time needed for completion of the project would be 

extended appreciably. 

4.17.3.2 Alternative A―100-Percent Vertical Drilling 

Overall noise generated as a result of drilling 100 percent of the project wells vertically, as opposed to the 

Proposed Action, which includes drilling 42 percent or 3,760 of the wells directionally, would not change 

the analysis of impacts when compared to the Proposed Action. The number of days needed for drilling 

and completion of individual wells may be slightly less for vertical wells when compared to directional 

wells and result in an overall reduction in the number of days of drilling and completion noise generated 

during development of the project. 

Construction, drilling, and completion activities related to the drilling of vertical conventional wells may 

last from 30 to 60 days. If it takes an additional week (7 days) to drill a well directionally, then the total 

number of days affected by drilling and completion noise would decline substantially under this 

alternative. However, 100-percent vertical wells would also require 42 percent more rig moves and the 

associated noise from rig moves within the field, when compared to the Proposed Action. In addition, the 

number of well completion semi-truck trips may also increase as a result of this alternative. 

Directional wells may also require a larger rig with larger engines, which may operate at higher decibel 

and frequency levels when compared to the rigs needed to drill vertically. The noise level, frequency of 

noise generation, or distance from which noise from larger engines is perceived may decline under 

Alternative A. 

4.17.3.3 Alternative B: Enhanced Resource Protection 

Design features of Alternative B, as detailed in Chapter 2, would serve to reduce noise in sensitive 

environments. For example, (1) clustered development would concentrate noisy activities rather than 

having noise sources dispersed across the project area, (2) use of noise-reduction technology would 

prevent noise exceeding 49 dBA measured at 30 feet from the source at all drilling, production, and 

compressor sites, (3) pipeline transportation of produced liquids would reduce semi/haul truck traffic and 

associated noise, and (4) remote well-monitoring would also reduce daily traffic near sage-grouse leks 

and in crucial big game habitats. Enhanced seasonal restrictions on surface-disturbing or disruptive 

activities within buffers associated with sage-grouse leks, mountain plover nesting habitat, and 

ferruginous hawk nests would reduce noise impacts on these sensitive species. 

4.17.3.4 Alternative C: Surface Disturbance Cap – High and Low Density Development Areas 

Implementation of Alternative C could result in areas with concentrated development activity as well as 

areas of more dispersed operations. It is likely that development noise levels within the high-density areas 

would be greater than those found in the low-density development areas. The Surface Disturbance Cap 

approach could slow the pace of development, especially in the high-density development areas, to the 

point that elevated development noise levels were extended in time compared to the Proposed Action. 

4.17.3.5 Alternative D: Directional Drilling 

Alternative D would likely result in an extension of the period of time over which a sensitive receptor is 

impacted by drilling noise. The engine size required for directional drilling would be larger and may 

result in a higher, or more noticeable, level of noise impacting a sensitive receptor. Noise resulting from 

completion activities and flaring would also be extended over a longer period of time at any one drilling 

site. These extended and possibly enhanced noise levels could result in a greater frequency of 

displacement by sensitive receptors. 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—NOISE 

4.17.3.6 Alternative E: No Action 

Under the No Action alternative the noise generated by currently authorized and approved development 

and production operations would continue. No new noise sources would be produced. 

4.17.4 Impact Summary 

The Proposed Action (8,950 wells, of which an estimated 3,760 could be directional) may result in an 

increase in the number of rigs running annually in order to accomplish the goal of completion of resource 

development in 15 years when compared to Alternative A, 100-Percent Vertical Drilling. Noise impacts 

would differ somewhat among the alternatives with noise sources potentially being more dispersed across 

the landscape under the disturbance cap alternative (Alternative C) or extended over time. 

The duration of noise-generating activity and dispersal of noise-generating equipment across the project 

area would be greatest under the Proposed Action. Directional wells are considered in the Proposed 

Action and Alternatives B, C, and D. Directional drilling may require a larger rig with larger engines, 

which may operate at higher decibel and lower frequency levels when compared to the rigs needed to drill 

vertically. The noise level, frequency of noise generation, or distance from which noise from larger 

engines is perceived may decline under Alternative A. Alternative D (Directional Drilling), while these 

rigs are a more intensive noise source, would result in an overall reduction in well pads and roads built 

and provide only localized areas of noise. 

Alternative A, 100-Percent Vertical Drilling, would result in the greatest number of generation sources. 

The number of days needed for drilling and completion of individual wells may be slightly less for 

vertical wells when compared to directional wells and result in an overall reduction in the days of drilling 

and completion noise generated in the development of the project. The time savings realized from vertical 

drilling could be negated by the amount of time it takes for a rig move; furthermore, the noise reductions 

realized from Alternative B could be negated by the noise of semi/haul trucks moving drilling rigs. The 

greatest difference between the Proposed Action and Alternative A could possibly be reduction in the 

low-frequency noise generated by the bigger engines on directional rigs. 

Design features of Alternative B, as detailed in Chapter 2, would serve to reduce noise in sensitive 

environments. 

4.17.5 Unavoidable Adverse Impacts and Additional Mitigation Measures 

Under the Proposed Action and all alternatives, construction, drilling, and flaring activities would 

generate onsite noise levels exceeding the EPA-established maximum of 55 dBA. In addition, haul trucks 

and other construction traffic would generate transitory noise exceeding the federal maximum. In general, 

these would be short-term events lasting up to 20 days for directional wells and up to 60 days for 

conventional wells. However, when considered over the life of the Proposed Action, the increased noise 

levels resulting from drilling and completion activities at multiple sites within the project area would 

continue for up to 15 years, until the resource is fully developed. Over the life of the project, compressor 

stations and well-site compression would generally be louder and frequent or continual sources of noise. 

However, full and successful implementation of the required mitigation measures as set forth in the 

Rawlins RMP and CD-C required Conditions of Approval and BMPs (Appendix C) would ensure that 

the significance criterion is not exceeded. 

In Appendix 15 of the RMP (Best Management Practices) there is a general statement requesting 

consideration of “noise reduction techniques and designs” to benefit wildlife in general and the greater 

sage-grouse in particular. Implementation of mitigation measures should be considered on a site-specific 

basis. The following additional mitigation measures would also be considered: 

	 Dampen or reduce noise from field-development and production activities with the use of 

mechanical mufflers, vegetative or constructed screening, and direction from receptor, topography, 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—NOISE 

or distance. Noise is also affected by environmental factors such as humidity, wind direction and 

speed, and air density. 

	 Consider the prevailing wind direction when siting noise-generating operations to lessen the impact 

of noise on sensitive receptors. 

	 Use flowback separators within 0.25 mile of sensitive receptors. 

	 Reduce semi/haul truck traffic with the installation of gathering pipelines for produced water and 

condensate. 

	 Install remote well-site monitoring to reduce light-truck traffic. 

	 Modify or enclose compressors to minimize or eliminate loud, continuous noise during greater sagegrouse strutting periods from March 1 through May 20 each year within 0.25 mile of strutting 

grounds. 

	 Avoid noise-generating activities from 6 p.m. to 9 a.m. within 2 miles of strutting grounds. 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—RANGE RESOURCES 

 MANAGEMENT ENVIRONMENT 

4.18 RANGE RESOURCES 

4.18.1 Introduction 

The CD-C project area includes lands that are located within 47 grazing allotments (described in Section 

3.18). In many cases, the boundaries of these allotments extend beyond the boundaries of the CD-C 

project area. Under all alternatives, cattle and sheep grazing would continue throughout the duration of 

the project. Impacts to rangeland resources would result with implementation of all alternatives. Impacts 

would be the greatest during the natural gas project development phase but would occur throughout the 

life of the project, due to vegetation and soil disturbance associated with construction activities, 

reclamation, weed-control, and road construction and use (e.g., fugitive dust and animal collisions). 

4.18.2 Management Objectives and Impact Significance Criteria 

The Rawlins RMP (BLM 2008a) includes the following management objectives for livestock grazing: 

1.	 Maintain, restore, and enhance livestock grazing to meet Wyoming Standards for Healthy
 

Rangelands (RMP Appendix 8) and achieve allotment objectives. 

2.	 Encourage grazing permittees and the interested public to participate with BLM to monitor and 

evaluate rangeland health to determine appropriate management actions. 

3.	 Utilize livestock grazing management techniques (RMP Appendix 19) to maintain vegetation 

communities and ecosystem functions, in consultation and coordination with the grazing permittees 

and with participation by the interested public. Utilize data collected from scientifically based 

inventory and monitoring techniques to support decisions that authorize livestock grazing levels and 

management. 

4.	 When feasible and providing Wyoming Standards for Healthy Rangelands are met, maintain and/or 

increase animal unit month (AUM) levels in the RMP project area for livestock grazing. 

5.	 Identify opportunities and implement range and vegetation improvement projects to sustain and 

enhance livestock grazing and meet Wyoming Standards for Healthy Rangelands in cooperation, 

consultation, and coordination with the grazing permittees and the interested public (Appendix 19). 

6.	 Mitigate direct, indirect, and cumulative livestock forage losses and impacts to livestock grazing 

(including impacts on livestock grazing operational capabilities and production performance) where 

opportunities exist. 

Impacts to rangeland resources would be considered significant if: 

1.	 Resource management actions result in greater than 10 percent permanent reduction in AUMs 

available for livestock grazing within a given allotment, 

2.	 Resource management actions reduce or eliminate the opportunity to run the livestock of choice, 

3.	 Wyoming BLM Standards for Healthy Rangelands are not met, or 

4.	 Vegetation significance criteria are exceeded (Section 4.6.2). 

4.18.3 Direct and Indirect Impacts 

Impacts to livestock and grazing resources would occur under the Proposed Action and all action 

alternatives on all lands in the project area, as well as on private and state lands under the No Action 

Alternative. The impacts would include those caused by a reduction of total available forage, road 

construction and maintenance, well pad construction, pipeline construction, improperly fenced open pits, 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—RANGE RESOURCES 

vehicle traffic, fugitive dust creation, accidental spills of hazardous or other materials, and creation of 

habitats conducive to invasive weed infestations. 

The primary impact to grazing resources would be loss of available forage as a result of construction and 

production-related disturbances. Available forage would be reduced during drilling and field development 

and would be partially reclaimed as soon as feasible under direction of the current BLM reclamation 

guidelines and recommendations (Appendix E). A long-term loss of forage would occur under all 

alternatives by construction of roads, drill pads, and ancillary facilities that remain in place throughout the 

life of the project. In addition, in areas where vegetation resources have been enhanced, disturbance 

would not only reduce quality and quantity of diverse vegetation but would also result in wasted 

investments by the BLM and permittees (for example, tebuthiuron [Spike 20PTM] treatments). 

While new roads, pipelines, and well pad construction produce adverse impacts such as removing 

available forage, the construction of new roads could provide beneficial impacts for livestock permittees 

from improved access to remote facilities and grazing areas. However, increased access could produce an 

increased disturbance to livestock, an increased number of undesignated roads/trails, and increased 

distribution problems associated with unclosed cattle gates and/or cut fences. Vehicles would also present 

a potential collision hazard to livestock, especially during the calving/lambing season and at night. 

For all of the alternatives, fugitive dust caused by vehicles traveling along proposed new roads, existing 

roads, and other areas of surface disturbance could settle on vegetation used as forage, especially 

alongside roadway corridors with heavy traffic. This dust would affect the quality and regenerative 

capacity of roadside grasses and forbs as well as decrease the palatability of the forage for 

livestock/wildlife use and potentially increase operating costs through increased livestock medical 

expenses (see Section 3.6.3). The graveling of roads reduces dust in the short term, but the scoria 

commonly used breaks down faster than other gravels and, in the long term, fugitive scoria dust covers 

the vegetation. Livestock forage would also be impacted should any spills of fuels, solvents, or drilling 

fluids occur. 

Areas of disturbed soil would lead to the spread of invasive plant species. These species would reduce 

rangeland and forage values by replacing preferred forage species, leading to a reduction in grazing 

capacity. Without proper management and control, invasive plant species may become established and 

cause wide-spread infestations. Additionally, some invasive species such as halogeton, black henbane, 

and houndstongue are poisonous to livestock and can kill or impair them if ingested. 

Livestock management concerns with development of natural gas resources on public lands in the CD-C 

project area include reclamation success, rangeland improvement functionality, dust from roads, and 

livestock losses. In general, adequate reclamation efforts within the project area have been hampered by 

inadequate reclamation techniques and extended drought conditions. Invasive weed control has been 

sporadic and random in implementation, which results in a threat to maintaining Wyoming BLM 

Standards for Healthy Rangelands and watershed health. 

Cattle guards and gates are often damaged by overweight/over-width loads, leading to added maintenance 

and unwanted mixing of livestock. Numerous instances of gates being left open or fences cut for pipelines 

that have not been closed or repaired adequately have been recorded. This has led to mixing of livestock 

and additional time for herding. In large allotments, this may involve up to a week of additional time and 

expense for the livestock operator. 

Improving roads leads people to drive faster, which has increased the incidences of young lambs, calves, 

and even full-grown animals being hit and killed or maimed. 

4.18.3.1 Proposed Action 

Under the Proposed Action (Section 2.2.1), approximately 8,950 new natural gas wells and the 

construction of required ancillary facilities would be anticipated over the course of the 15-year 

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development phase within the CD-C project area. It is assumed that 42 percent of the wells (3,765) would 

be drilled from directional drilling pads. Over the development phase, the Proposed Action is estimated to 

initially disturb a total of 47,200 surface acres (Table 4.0-1). This total represents an initial forage loss 

equivalent to approximately 5,488 AUMs, based upon an allotment-wide average of about 8.6 acres per 

AUM stocking ratio. During the projected 45- to 55-year life of the project, the initial 47,200 acres of 

disturbance would be reduced to about 18,861 acres resulting in a long-term forage loss equivalent to 

about 2,193 AUMs. 

In addition to the 47,200 acres initially disturbed by implementation of the Proposed Action, an estimated 

initial total of 60,176 historic disturbance acres already exist within the project area (Table 4.0-1). The 

existence of 60,176 initial historic disturbance acres added to Proposed Action disturbance acreage would 

result in a grand total of 107,376 initial disturbance acres or about 10 percent of the total land surface of 

the project area. During the projected 45- to 55-year life of the project, the overall disturbance would be 

reduced to about 36,524 acres, or about 3.4 percent of the total land surface in the project area with 

successful reclamation on all disturbed acres. The driving factors for attaining pre-disturbance conditions 

would mainly depend upon time to achieve successful reclamation, future land uses, and future climatic 

conditions. This would hold true for the reclamation of herbaceous species, but not for native shrub 

establishment, especially in the more xeric portions of the project area where Wyoming big sagebrush and 

Gardner’s saltbush are the primary land cover types on approximately 590,272 acres, which represents 

about 55.1 percent of the project’s total land surface area (Table 3.6-1). 

The first impact significance criterion described in Section 4.18.2 says that impacts to rangeland 

resources would be considered significant if they were to result in a permanent reduction in AUMs 

available for livestock grazing within an allotment that was greater than 10 percent. Such a reduction 

would be a decision made by BLM on a case-by-case basis after a thorough examination of an allotment’s 

historic and ongoing forage availability. Ultimately the decision would be based on the long-term loss of 

available forage within the allotment. While this analysis cannot say how much disturbance each 

allotment would receive as a result of the CD-C project and to what extent that would translate to a longterm loss of available forage, it is possible to estimate which allotments may be at a greater risk of longterm loss of forage in excess of 10 percent. According to Table 3.18-2, the Echo Springs and North 

LaClede allotments have already had historic initial surface disturbance in excess of 9 percent. Nine other 

allotments have had historic disturbance in excess of 5 percent but less than 9 percent. Assuming some 

degree of successful reclamation and a return to pre-disturbance vegetative conditions, none of these 

allotments may currently be near the 10 percent significance threshold, as the long-term disturbance 

figures in Table 3.18-2 would indicate. However, the surface disturbance associated with the Proposed 

Action—47,200 acres—could bring total initial disturbance to almost 10 percent of the overall project 

area. If previously disturbed areas are not being returned to pre-disturbance vegetative conditions, then 

the allotments described in the preceding sentences—and others—could be at risk of long-term forage 

reductions in excess of 10 percent. 

Indirect impacts to vegetation due to dust from unpaved roads would be variable throughout the project 

area, depending upon the primary factors cited in Section 3.6.3. In addition to the primary factors that 

generate dust on unpaved roads, the amount and timing of precipitation events—especially in the hotter 

and drier summer season—could play an important role in the amount of dust generated. Wind speed and 

prevailing direction in relation to the horizontal azimuth of the road would be important secondary 

factors, especially with north/south-oriented roads such as Sweetwater County Road (SWCR) 23 which 

extends from Wamsutter to the north boundary of the project area. The poor palatability of dust-covered 

vegetation could cause animals to concentrate in dust-free locations, leading to over-utilization and 

lowered plant productivity/cover in these areas. Increased dust may also affect animal health. These 

impacts could include reduced weight gains or required lowering of stocking rates in affected allotments. 

The Proposed Action could result in impacts to livestock operations as a result of increased death loss, 

unusable forage due to dust, declining rangeland health and forage productivity, and disruptions to 

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livestock-management actions. Suggestions for voluntary coordination may or may not be implemented 

and death loss of young animals and disruptions to livestock-management actions would still be likely to 

occur. Existing standards and mitigations may not adequately address issues with dust and road 

alterations to overland hydrology. Therefore, reduction in forage palatability from dust and declining 

rangeland health and productivity due to accelerated erosion from roads could still occur. 

The Proposed Action would result in increased traffic and increased speeds on the improved roads within 

the CD-C project area, particularly during the drilling and field-development phase. The potential for 

livestock/vehicle collisions would be increased, especially during the calving/lambing season and during 

nighttime hours. Roads on moderate to steep slopes that result in long-term changes to overland 

hydrology and desertification impacts below these locations would also lead to lower weight gains or 

require reduced stocking rates. New and improved access roads could, however, improve livestock 

operations by improving access for viewing the allotment, facilities, and animals; for doctoring sick 

animals; and for transporting animals in or out of an allotment. 

The potential exists for disruptions to livestock management. Traffic along roads that pass through 

shipping pastures or by corrals when in use may interrupt or complicate this work, extending the time and 

increasing the cost to complete it. Herding of animals through areas being developed or moving around 

them would increase the complexity and time to accomplish these tasks. In some allotments, management 

flexibility may be sacrificed to avoid or to minimize these types of impacts. 

There is also potential for damage to range improvements from the movement of heavy trucks, drilling 

equipment, and heavy construction equipment. 

Disturbance of soils and increased vehicle activity would increase the potential for introduction, 

establishment, and spread of undesirable non-native weedy species. This can reduce forage palatability 

and animal weight gains, in addition to affecting trail routes and animal health, particularly increasing 

death loss with sheep. 

4.18.3.2 Alternative A: 100-Percent Vertical Drilling 

Alternative A (Section 2.2.2) is similar to the Proposed Action except this alternative assumes that no 

wells would be drilled using directional drilling rigs. Impacts to the range resource resulting from 

implementation of Alternative A would be similar to the Proposed Action with the exception that the total 

amount of initial disturbed area would increase from 47,200 acres to 61,696 acres, a 31-percent increase; 

the total long-term disturbed area following successful reclamation would increase from 18,861 acres to 

24,133 acres. 

Under Alternative A, the rangeland forage resource on the 47 CD-C grazing allotments would initially be 

reduced by the forage equivalent of approximately 7,174 AUMs (1,686 more AUMs than the Proposed 

Action). Assuming successful reclamation occurs, the long-term forage loss equivalent under Alternative 

A would be about 2,806 AUMs for the 47 allotments versus 613 more AUMs than the Proposed Action. 

The greatly increased disturbance acreage under this alternative would make it more likely that an 

allotment would approach or exceed the 10-percent significance criterion. The 61,696 acres of new 

disturbance amounts to a 110-percent addition to historic disturbance. If historic development patterns 

were to continue, some allotments, including the eleven that have historic disturbance in excess of 5 

percent, could be nearing the criterion percentage even if reclamation efforts were successful. 

The greater amount of construction activities, increased soil-surface disturbance, and higher traffic 

volumes associated with Alternative A would likely increase the potential for introduction and spread of 

invasive weed species, as well as increasing the total fugitive dust load within the project area. 

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4.18.3.3 Alternative B: Enhanced Resource Protection 

Alternative B (Section 2.2.3) was developed to prevent significant impacts to the range and other 

resources by implementing protections and mitigations beyond those normally applied. Alternative B also 

recognizes that development may be more intensive than currently expected and may result in impacts to 

vegetation communities faster than anticipated. This alternative would combine a prescriptive and 

adaptive management approach, which includes assessing the specific issue, designing and implementing 

a response, monitoring and evaluating results, and adjusting the management response when needed on a 

case-by-case basis. 

The enhanced resource protections for the livestock resource would go into effect immediately and be 

applied to all future APDs. They include mitigation of impacts on livestock water features, annual 

meetings conducted by the BLM with natural gas Operators and grazing permittees to discuss projectspecific impacts, notification of the affected grazing permittees when drilling is to take place within their 

allotment, thorough power-washing of all field vehicles associated with natural gas operations, and 

control of fugitive dust on well sites, pipelines, and access roads. 

Surface-disturbance thresholds would trigger further mitigation activities. If surface disturbance were to 

reach 5 percent of an allotment, a review of reclamation success in the allotment would take place and 

planning for further development, including potential range improvement projects, would take place. If 

the amount of unreclaimed surface disturbance were to reach 8 percent, the BLM would require that 

mitigation be implemented to avoid reaching the significance level of a permanent 10-percent loss of 

vegetation. 

Under Alternative B, the initial disturbance would be 45,516 acres (a decrease of 1,684 acres compared to 

the Proposed Action) resulting in an initial forage loss equivalent to approximately 5,293 AUMs (195 

fewer AUMs than the Proposed Action). Assuming successful reclamation efforts, the long-term 

disturbance area would decrease to 18,249 acres (a decrease of 612 acres compared to the Proposed 

Action) resulting in a long-term forage loss equivalent of about 2,122 AUMs (71 fewer AUMs than the 

Proposed Action). 

The decreased surface disturbance under this alternative would make it less likely that an allotment would 

approach or exceed the 10-percent significance criterion. More importantly however, the two thresholds 

would assure that timely intervention took place before the 10-percent significance threshold was 

approached. 

The reduction in the amount of construction activities, reduced soil-surface disturbance, and diminished 

traffic volumes associated with Alternative B would decrease the potential for introduction and spread of 

invasive weed species, as well as decreasing the total fugitive dust load within the project area. 

4.18.3.4 Alternative C: Cap on Surface Disturbance, 60 Acres and 30 Acres per Section 

Under Alternative C (Section 2.2.4), the types of impacts to the range resource would be similar to those 

described for the Proposed Action (Section 4.18.3.1). For this alternative, the scope and intensity of the 

impacts would be less widespread because of the surface cap restrictions. Under Alternative C, the 

maximum initial disturbance would be 42,955 acres (a decrease of 4,245 acres compared to the Proposed 

Action) resulting in an initial forage loss equivalent to approximately 4,995 AUMs (493 fewer AUMs 

than the Proposed Action). Assuming successful reclamation efforts, the long-term disturbance area 

would decrease to 17,318 acres (a decrease of 1,543 acres compared to the Proposed Action) resulting in 

a long-term forage loss equivalent of about 2,014 AUMs (179 fewer AUMs than the Proposed Action). 

With this alternative there would be fewer well locations developed. Therefore, fewer access roads would 

be developed and habitat fragmentation would be less extensive than for the Proposed Action. The 

impacts to the range resource associated with implementation of Alternative C would be similar in nature, 

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but somewhat less in magnitude, compared to impacts associated with the Proposed Action (Section 

4.6.3.1). 

The reduced surface disturbance under this alternative would make it less likely that an allotment would 

approach or exceed the 10-percent significance criterion. The 42,955 acres of new disturbance would be a 

9-percent reduction from the Proposed Action. However, this is still a substantial addition to historic 

disturbance and, if previously disturbed areas are not being returned to pre-disturbance vegetative 

conditions, then the 11 allotments with historic disturbance in excess of 5 percent—and others—may be 

at risk of long-term forage reductions in excess of 10 percent. 

On federal lands, invasive weed programs would be implemented per stipulations outlined in individual 

right-of-way applications and APDs. 

4.18.3.4 Alternative D: Directional Drilling 

Under Alternative D (Section 2.2.5), the types of impacts to the range resource would be similar to those 

described for the Proposed Action (Section 4.18.3.1) but the scope and intensity of the impacts would be 

less widespread because of the expected reduction in surface disturbance. Estimated initial surface 

disturbance for this alternative would be 36,449 acres, a decrease of 10,751 acres from the Proposed 

Action. The forage lost initially under this alternative is estimated to be 4,238 AUMs (1,210 fewer than 

the Proposed Action). The estimated 14,952 acres of long-term disturbance would be 3,908 acres less than 

the Proposed Action, representing 1,739 AUMs (454 fewer AUMs than the Proposed Action). 

The reduced surface disturbance under this alternative would make it less likely that an allotment would 

approach or exceed the 10-percent significance criterion. The 36,449 acres of new disturbance would be a 

22.8-percent reduction from the Proposed Action. However, this addition to historic disturbance could 

cause the 11 allotments with historic disturbance in excess of 5 percent—and others—to be at risk of 

long-term forage reductions in excess of 10 percent if previously disturbed areas are not being returned to 

pre-disturbance vegetative conditions. 

With this alternative there would be fewer well locations developed—an estimated 4,032 compared to the 

6,126 estimated for the Proposed Action. This 35-percent reduction in well locations would likely lead to 

similar reductions in the number of access roads and road miles with associated reductions in potential 

collision hazard and dust accumulation on nearby forage. 

4.18.3.5 Alternative E: No Action 

Under the No Action Alternative it is assumed that no further natural gas development would occur 

within the CD-C project area and there would be no new disturbance except where APDs have been 

approved by the BLM for previously authorized activities. There would consequently be no new surface 

disturbance and no new impacts on rangeland. Grazing would continue to be affected by earlier habitat 

alterations, by human activity in the vicinity of natural gas production facilities, by traffic in the project 

area, and by diminished palatability of forage caused by dust. 

4.18.4 Impact Summary 

Rangeland impacts associated with the Proposed Action and Alternatives would include disturbed land 

and associated loss of available forage. Other impacts include those from dust-reducing forage 

palatability, impacts to livestock operations (e.g. leaving gates open, impacts to fences or range 

improvements), possible increases in invasive plant species, and accidental injury or death of livestock 

from vehicle collisions. Table 4.0-1 shows the anticipated surface disturbance for the alternatives 

compared to the Proposed Action. 

Under the Proposed Action, assuming reclamation and reseeding efforts are successful, during the 

projected 45- to 55-year life of the project, the initial 47,200 acres of disturbance would be reduced to 

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about 18,861 acres, resulting in a long-term loss of about 2,193 AUMs. Two allotments and possibly 

more would be at risk of exceeding the RMP significance criteria of a permanent reduction in AUMs 

greater than 10 percent. 

Under Alternative A, the initial 61,696 acres of disturbance would be reduced to about 24,133 acres over 

the life of the project, resulting in a long-term loss of about 2,806 AUMs. Allotments would be at a 

greater risk of exceeding the RMP significance criteria of a permanent reduction in AUMs greater than 10 

percent. 

Under Alternative B, the initial 45,516 acres of disturbance would be reduced to about 18,249 acres over 

the life of the project, resulting in a long-term loss of about 2,122 AUMs. Many of the impacts associated 

with the Proposed Action would be reduced under this alternative (e.g. dust, controlling the spread of 

invasive plants, and impacts to range improvements). The two-phase process to identify allotments which 

are approaching the RMP significance criteria should reduce the risk of allotments exceeding the criteria. 

The use of surface-disturbance caps under Alternative C would result in reduced surface impact. During 

the life of the project, the initial 42,955 acres of disturbance would be reduced to about 17,318 acres, 

resulting in a long-term loss of about 2,014 AUMs. The reduced surface disturbance under this alternative 

would make it less likely that an allotment would approach or exceed the 10-percent significance criterion 

but, if previously disturbed areas are not being returned to pre-disturbance vegetative conditions, then 

some allotments may be at risk of long-term forage reductions in excess of 10 percent. 

Under Alternative D, the initial 36,449 acres of disturbance would be reduced to about 14,952 acres over 

the life of the project, resulting in a long-term loss of about 1,739 AUMs. The reduced surface 

disturbance under this alternative would make it less likely that an allotment would approach or exceed 

the 10-percent significance criterion but, if previously disturbed areas are not being returned to predisturbance vegetative conditions, then some allotments may be at risk of long-term forage reductions in 

excess of 10 percent. 

Because it is assumed that there would be no development under Alternative E, No Action, there would 

be no new impacts of the type described in the Proposed Action, such as deaths of livestock and damage 

to fences and other range improvements. Grazing would continue to be affected by earlier habitat 

alterations, by human activity in the vicinity of natural gas production facilities, by traffic in the project 

area, and by diminished palatability of forage caused by dust. 

4.18.5 Unavoidable Adverse Impacts and Additional Mitigation Measures 

Rangeland impacts associated with the CD-C project—a reduction in available forage, reduced forage 

palatability, negative effects on livestock operations (e.g. leaving gates open, damaged fences and range 

improvements), accidental injury or death of livestock from vehicle collisions—would continue 

throughout the life of the project. The most effective mitigation for reduced forage is to minimize the 

amount of new disturbance. Alternatives C and D would produce the least amount of new disturbance. 

Impacts would be further reduced with the application of mitigation measures found in Appendix C and 

the successful implementation of current BLM reclamation guidelines and recommendations described in 

Appendix E. The addition of the following measures not found in Appendix C would further minimize 

impacts to the range: 

	 The Operators could, in cooperation with the applicable county, establish reasonable speed limits 

within the project area, such as Carbon County has done on 20 Mile Road south of Rawlins, to 

enhance personnel safety, reduce fugitive dust, and reduce potential for livestock/wildlife/wild horse 

collisions 

	 Heavy equipment exceeding the recommended gross vehicle weight would not be allowed to use 

cattle guard crossings. 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—RANGE RESOURCES 

 All gates within the project area would be left as they are found (i.e., open gates would be left open, 

closed gates would be closed). 

 The Operators could coordinate with affected livestock operators to minimize disruption during 

livestock operations, including lambing/calving season. 

 The BLM could require that off-road activity be minimized. 

 The BLM could require that no vehicle activity be allowed on recently reclaimed sites (including 

pipeline rights-of-way), wetland areas, or other sensitive sites. 

	 Sites undergoing reclamation could be signed at all possible entry sites, especially gathering 

pipelines that connect several well pads. Signs should state “Authorized Vehicles Only” to allow 

maintenance work on valves, for example, by responsible Operators. 

Where vegetation improvement projects exist, additional acreage may be treated to replace disturbance 

impacts and balance or reimburse investment costs for the permittees and BLM. 

4.19 OIL AND GAS AND OTHER MINERALS 

4.19.1 Introduction 

The Proposed Action and the action alternatives would involve recovery of natural gas resources, which 

would cause a loss of reserves in the ground. The recovered natural gas would provide a needed energy 

resource and would generate private and public revenues. 

The occurrence and potential for occurrence of locatable and other leasable mineral resources have been 

identified in the project area (Section 3.19). Although potential for development of those resources is low, 

their development would not be precluded by the development of the oil and gas resource. Multiple 

development of public land minerals is anticipated by regulation and the granting of oil and gas leases and 

permits to develop those leases does not “preclude the issuance of other permits or leases for the same 

lands for deposits of other minerals with suitable stipulations for simultaneous operation, nor the 

allowance of applicable entries, locations or selections of leased lands with a reservation of the mineral 

deposits to the United States.” (43 CFR 3000.7) The development of natural gas would in turn require the 

development of aggregate minerals—sand, gravel, and klinker—for building materials for roads, well 

pads, and other ancillary facilities. 

4.19.2 Management Objectives and Impact Significance Criteria 

The Rawlins RMP (BLM 2008a) prescribes the following management objectives for mineral resources: 

1.	 Provide for exploration and development of locatable minerals, except in withdrawn areas. 

2.	 Provide opportunities for exploration and development of conventional and unconventional oil and 

gas, coal, and other leasable minerals. 

3.	 Provide opportunities for exploration and development of salable minerals. 

Impacts of the CD-C project would be considered significant if they: 

1.	 caused a substantial reduction in leasing and development of non-oil and gas leasable minerals. 

2.	 caused a substantial reduction in the development of locatable and salable minerals. 

4.19.3 Direct and Indirect Impacts 

4.19.3.1 Proposed Action and All Action Alternatives 

Some deposits of uranium are known to occur within the project area but no development is occurring and 

none is anticipated in the foreseeable future and so no impacts are expected. The principal leasable 

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minerals found in the project area are coal and natural gas. Coal seams of the Fort Union Formation, the 

Lance Formation, and the Mesaverde Group are found within and adjacent to the project area but no 

development is occurring and none is anticipated in the foreseeable future. The Proposed Action and 

action alternatives are not expected to affect the coal resource in any way. 

Development of the natural gas resource would be affected by the Proposed Action and alternatives. 

Successful natural gas field development would result in the ultimate recovery of the natural gas resource 

from the target formations, under economic conditions favorable to development, and would substantially 

increase natural gas supply, regionally and nationally. Under the Proposed Action and all action 

alternatives, recoverable natural gas reserves produced over the life of the project are estimated at 12.02 

Tcf; liquid condensate is estimated at 167.3 million barrels (Section 4.14.2.2, Socioeconomics). With this 

amount of production from the target formations, it is expected that the oil and natural gas resource in the 

CD-C project area would have been substantially depleted, pending new technology or the discovery of 

new reserves. 

Development of surface mineral material deposits mined in support of CD-C development activities 

would occur as a result of any of the action alternatives. Construction-grade materials such as sand, stone, 

gravel, pumice, pumicite, clay, and rock are likely to be obtained from local sources. Currently permitted 

sources have been identified (Map 3.19-1) and other sources are likely to be developed. The total 

quantities required are not known.. 

4.19.3.2 Alternative E -- No Action

Under Alternative E, No Action, it is assumed that no new development would take place and no more 

reserves of natural gas or liquid condensate would be produced in the CD-C project area. 

4.19.4 Impact Summary 

Under the Proposed Action and all action alternatives, the fluid mineral resources of the CD-C project 

area would be developed fully—12.02 Tcf of natural gas and 167.3 million barrels of liquids— in the 

context of known reserves and current extraction technologies. Under Alternative E, it is assumed that the 

fluid mineral resources would not be developed. Development of surface mineral material deposits mined 

in support of CD-C development activities would not occur. Deposits of coal and uranium are not 

expected to be affected by the Proposed Action and the action alternatives. 

4.19.5 Unavoidable Adverse Impacts and Additional Mitigation Measures 

Because no unmitigated adverse impacts are expected, no additional mitigation measures would be 

necessary. 

4.20 HEALTH AND SAFETY 

4.20.1 Introduction 

Health and safety impacts associated with the action alternatives would be similar to those associated with 

existing conditions in the project area. As the level of gas development increases in the area the potential 

for accidents increases due to the number of vehicles, rigs, other heavy equipment, and personnel in the 

area. The greatest potential for health and safety impacts includes the occupational hazards associated 

with oil and gas exploration and development, and vehicular travel on improved and unimproved roads. 

4.20.2 Management Objectives and Impact Significance Criteria 

The Rawlins RMP (BLM 2008a) does not identify any specific health and safety standards or impact 

significance criteria. 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—HEALTH AND SAFETY 

In general, health and safety effects of the action alternatives would be considered significant if they 

resulted in substantially increased risk to the general public. Health and safety are regulated by state and 

federal environmental and safety agencies such as the WDEQ, the EPA, OSHA, Wyoming OSHA, and 

the WOGCC. 

4.20.3 Direct and Indirect Impacts 

4.20.3.1 Proposed Action 

Direct and indirect health and safety risks arising from the Proposed Action include oil and gas 

occupational hazards, the operation of vehicles on improved and unimproved roads, natural gas pipeline 

operations, winter driving and working conditions, hunting-related firearms accidents, collisions with 

livestock and big game, and natural hazards associated with wildfires, flash-floods or winter blizzards. A 

wide variety of hazardous materials are handled and used in gas-field development and operations 

activities, resulting in an increased risk of inappropriate use, disposal, or accidental release. 

Health and safety impacts to the project workforce include industrial and vehicle accidents. Impacts to the 

general public are generally limited to an increased risk of traffic accidents. The risk of occupational 

hazards declines substantially once development activities (drilling and completion operations) are 

concluded. The risk of vehicle accidents impacting the general public and the workforce may decrease 

during the field-operations phase depending on the volume of produced water and condensate being 

transported by truck to disposal or sale. 

Hazardous materials storage/use and waste management are stringently regulated by the BLM, EPA, 

WDEQ and WOGCC, and are discussed in Sections 3.21 and 4.21. The risk to human health and the 

environment from these materials is limited to regulatory non-compliance situations and accidental 

releases or spills. 

Occupational and Public Hazards 

Health and safety concerns associated with the Proposed Action would be similar to those described in 

Section 3.20. Implementation of the Proposed Action would likely result in an increased risk to the 

workforce due to the increased number of personnel in the field, the increase in heavy equipment use and 

drilling operations, and the resultant increase in vehicle traffic. Compliance with the State of Wyoming 

Department of Employment Workers Occupational Health and Safety (WOSHA) program rules and 

regulations for construction and oil and gas well drilling, well servicing, and well special servicing 

operations would aid in reducing project-related occupational hazards. In addition, the BLM considers 

safety issues during the APD review process (Onshore Order #1) and reminds the Operator of its 

occupational health and safety responsibilities in 43 CFR Ch. II, 3162.5-3. Compliance with the OSHA 

standards works to reduce the opportunity for occupational injuries. 

The remote nature of the project area further reduces the opportunity for development and productionrelated hazards to impact the general public. The public using state and federal highways would be 

affected by increased levels of traffic, specifically semi/haul truck units related to drilling and completion 

operations and produced-water and condensate-hauling activities. General public use of lease roads is 

generally related to livestock activities and recreation, including hunting. Persons pursuing these activities 

would be at a greater risk of collision with pick-up trucks being driven by field personnel (pumpers and 

field technicians) and semi-haul trucks. Compliance with WOGCC underground power certification 

regulations would reduce the opportunity for faulty electrical installations on well sites. In addition, the 

extremely rural nature of the area and land-ownership patterns (the “Checkerboard”) do not encourage or 

support residential development, further reducing the opportunity for the public to be affected by 

underground electrical hazards and other possible hazards. 

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Pipeline Hazards 

Implementation of the Proposed Action would increase the miles of gas-gathering and transmission 

pipeline installed in the project area as well as the number of natural gas compression and stabilization 

facilities. Natural gas transmission and gathering pipeline operations are regulated by the federal Office of 

Pipeline Safety (OPS). Operators of the gas-transmission infrastructure are required to comply with the 

applicable OPS regulations including implementing stringent system maintenance programs, emergency 

response planning, risk-management planning, and task specific personnel training in operations and 

maintenance for each natural gas pipeline system. Compliance with the OPS program requirements 

reduces the opportunity for pipeline accidents and, likewise, the risk to the general public and employees. 

Other Risks and Hazards 

The opportunity for accidents involving the general public and the workforce increases as the volume of 

activity in the field and on the road increases. All actions required to implement the Proposed Action 

would result in some increased level of risk to the general public and the workforce. Effective contractor 

and personnel training, emergency-response planning, and coordination with emergency responders 

should reduce the risks associated with field development and operations. 

Highway and road-safety impacts related to the Proposed Action and alternatives are discussed in Section 

4.16 Transportation. There are inherent risks associated with the operation of vehicles on improved and 

unimproved roads. Awareness training alerts field personnel to variable road-surface conditions including 

the risk of collision with the general public, livestock, and wildlife. As a result of greater access to 

previously inaccessible areas, the public may also be exposed to hazardous driving conditions and 

wildlife on the roads. With the exception of semi-haul trucks, the public would be exposed to these same 

hazards wherever they were recreating; the hazards of backcountry recreation are not limited to the 

project area. 

The public would be exposed to an increased number of large vehicles on county roads and state and 

federal highways resulting in a greater risk of being involved in an accident. For example, the number of 

semi trucks needed to accomplish a fracking operation is substantial; when multiplied by 600 wells being 

completed each year the number of additional large trucks on the roadways is also substantial. The drivers 

of these commercial big-rigs are required to hold commercial driver’s licenses with special operations 

endorsements and receive training prior to operating such vehicles; however, this does not preclude the 

possibility of accidents. 

Weather-related hazards due to winter driving and working conditions could impact the general public 

and the workforce. 

Natural or accidental fires also pose a risk to the workforce and the public. Adherence to the BLM 

seasonal fire restrictions and the OPS pipeline regulations would reduce the opportunity of fire-related 

injury and property loss. Fire as a result of natural gas development and production activity would likely 

result in damage to the field equipment and the range resource. The opportunity for privately owned 

structures to be involved in such incidents would be limited; very few privately owned structures exist in 

the project area outside of Wamsutter. 

Hunting-related firearms accidents would be a remote possibility. Site workers are generally proximal to 

field infrastructure and conscientious hunters avoid shooting toward facilities. The hunting public is at 

risk for such accidents regardless of where they are hunting. Operations personnel and contractors are not 

allowed access to firearms when working. 

Risk to the public as a direct result of development and production operations is limited. Harm caused by 

extreme noise events would be limited to situations when individuals might place themselves in close 

proximity to the noise-emitting operation; noise is discussed in greater detail in Sections 3.17 and 4.17. 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—HEALTH AND SAFETY 

4.20.3.2 Alternative A: 100-Percent Vertical Drilling 

The impacts of implementing Alternative A would be the same as those resulting from the Proposed 

Action with the exception that drilling vertical wells could result in fewer days of concentrated drilling 

activity per well when compared to drilling directional and pad wells and, therefore, a slightly lower risk 

of occupational hazard exposure for the drilling workforce. 

4.20.3.3 Alternative B: Enhanced Resource Protection 

The impacts of implementing Alternative B would be the same as those resulting from the Proposed 

Action. 

4.20.3.4 Alternative C: Surface Disturbance Cap – High and Low-Density Development Areas 

The impacts of implementing Alternative C would be the same as those resulting from the Proposed 

Action with the exception that travel-related risks to the recreating public may be higher in high-density 

development areas when compared to low-density development areas. 

4.20.3.5 Alternative D: Directional Drilling 

The impacts of implementing Alternative D would be the same as those resulting from the Proposed 

Action. The implementation of the Directional Drilling requirement could slow down development to the 

extent that it reduces, somewhat, road travel risk to the public. 

4.20.3.6 Alternative E: No Action 

Under the No Action alternative, occupational health and safety exposure to site workers and exposure to 

the public would be greatly reduced because it is assumed that no new wells would be drilled. Some 

exposure would still exist with ongoing production activities. 

4.20.4 Impact Summary 

The Proposed Action and all action alternatives would result in similar impacts to the public and site 

workers including increased risk of vehicle collisions on interstate highways and local road systems. 

4.20.5 Unavoidable Adverse Impacts and Additional Mitigation Measures 

Any increase in the volume of activity in the natural gas field required to implement the Proposed Action 

and alternatives would increase the risk of accidents and injury to the workforce from project-related 

activities as well as weather-related incidents, wildfires, and increased noise levels. The resulting increase 

in traffic using the local transportation network would increase the risk of vehicle collisions with other 

vehicles, wildlife, and livestock for the workforce as well as the general public. However, effective 

contractor and personnel training, emergency-response planning, and coordination with emergency 

responders should reduce the risks associated with field development and operations. The level of risk 

would be highest during project development. 

The operating companies and their contractors are obligated to operate in compliance with applicable 

local, state, and federal regulations. The BLM recognizes these authorities and requires compliance with 

the applicable regulations. 

In addition to required mitigation measures as set forth in the Rawlins RMP and CD-C required 

Conditions of Approval and BMPs (Appendix C), the following mitigation measure would further reduce 

risks to human health and safety for the workforce and the public: 

 Consider cooperatively permitting and operating in-field liquids-gathering and road systems. 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—WASTE AND HAZARDOUS MATERIALS 

4.21 WASTE AND HAZARDOUS MATERIALS 

4.21.1 Management Objectives and Impact Significance Criteria 

Appendix 32 to the Rawlins RMP (BLM 2008a) sets out objectives for the Hazard Management and 

Resource Restoration Program (HMRRP), an administrative program that emphasizes management of 

hazards on public lands to reduce risks to visitors and employees, restore contaminated lands, and carry 

out emergency response actions. The HMRRP contains the following objectives: 

1.	 Identify and control imminent hazards or threats to human health and/or the environment from 

hazardous substance releases on public lands. 

2.	 Promote working partnerships with states, counties, communities, other federal agencies, and the 

private sector to prevent pollution and minimize hazardous waste on public lands. 

3.	 Provide hazardous materials management training to BLM employees and educate public land users 

concerning laws, rules, and standards. 

4.	 Require potentially responsible parties to undertake response actions and to pay their fair share or 

face cost recovery. 

5.	 Encourage public collaboration in environmental decision-making. 

6.	 Inventory, assess, and manage the cleanup of hazardous substance release sites on public lands that 

present a potential risk to human health and/or the environment, and promote healthy ecosystems. 

7.	 Ensure that solid and hazardous waste treatment, storage, and disposal facilities that might affect 

public lands are properly located, designed, and constructed, consistent with the law, as well as 

prohibit Resource Conservation and Recovery Act (RCRA) temporary storage facilities on public 

lands. 

8.	 Reduce hazardous waste produced by BLM activities and from authorized uses of public lands 

through waste minimization programs that include: recycling, reuse, substitution, and other 

innovative, safe, and cost-effective methods of pollution prevention. 

9.	 Ensure that authorized activities on public lands comply with applicable federal, state, and local 

laws, regulations, policies, guidance, and procedures. 

10. Ensure appropriate review of authorized activities and application of effective management controls 

to correct weaknesses. 

No specific waste and hazardous materials standards were identified in the Rawlins RMP; however, IM 

WY-2012-007, Management of Oil and Gas Exploration and Production Pits, includes several standards 

for waste management from oil and gas operations. This far-reaching IM is not restricted only to issues 

related to pit management. In general, waste and hazardous materials effects of the action alternatives 

would be considered significant if they resulted in substantially increased risk to the public. 

4.21.2 Direct and Indirect Impacts 

4.21.2.1 Proposed Action 

Waste Management 

Waste management impacts resulting from the Proposed Action would be similar to those currently in 

place in the project area. Most wastes that would be generated at project locations are exempt from 

regulation by the RCRA under the oil and gas exploration and production exemption and are considered 

to be solid wastes. Compliance with all applicable state and federal hazardous substance and wastemanagement regulations should minimize the threats to human health and the environment from 

generated waste streams (refer to Section 3.20.1). 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—WASTE AND HAZARDOUS MATERIALS 

Drilling wastes (mud and cuttings) would be generated from the drilling of each well. Fresh water/gel 

drilling mud would be used and reserve pits lined when site-specific conditions dictate. Oil-based fluid 

drilling would occur minimally and only in closed-loop drilling fluid systems. Reserve pit fluids (mud 

and water) would be recycled as much as possible to reduce water consumption and conserve mud 

products. Typically reusable fluids are transported and used to drill additional wells while the cuttings or 

solids are allowed to dry in the reserve pit before being buried onsite. If used, liners would also be buried 

onsite. In some situations the cuttings are solidified prior to burial, as allowed in the WOGCC regulations 

and with BLM approval. On multi-well pad sites the reserve pit would be used for all wells on the pad 

before being closed. Some Operators use closed-loop drilling fluids systems that reduce the need for 

reserve pit capacity and facilitate more efficient recycling and reuse of mud products. Reserve-pit 

management varies by Operator, contractor, and location. Commercial drilling mud-disposal facilities are 

limited and are experiencing disposal capacity problems. Reserve pits are fenced on three sides during 

operations and on the fourth side once the drilling rig moves off the location. 

Completion/stimulation fluids recovered during flow-back and subsequent production operations would 

be temporarily contained in completion, flare, or reserve pits, depending on site design and APD approval 

conditions. These fluids would ultimately be disposed of at evaporation ponds or disposal wells or 

evaporated onsite. Well bore construction (cement, casing, perforation, pressure testing, etc.) is designed 

and authorized to preclude the opportunity for completion fluids to impact groundwater or non-target 

hydrocarbon-bearing zones. 

Produced water from conventional wells would continue to be managed as described in Section 3.21.1. 

Produced-water injection is currently used on a limited basis in the project area. The anticipated volume 

of water produced per well is relatively low at an average of 18 barrels of water per day. However, given 

the number of additional wells to be drilled, the volumes anticipated are significant. The BLM considered 

requiring injection of produced water as the preferred method of management; however, the Operators 

have not been able to identify a reservoir that is capable of taking water at the volumes needed by the 

production rates projected in the area. Thirty additional water-injection wells are planned by the 

Operators to handle the anticipated volume of produced water, but injection appears to have limited 

potential for use within the overall project area. Some Operators currently have water evaporation ponds, 

which may need to be enlarged due to the increased volume of water produced. An additional 20 

produced-water management facilities (i.e. evaporation ponds) are anticipated. Commercial waterdisposal operations may also need to enlarge their facilities, as capacity is already limited. Produced water 

would be transported to off-site facilities by pipeline or truck when not managed at the well site. Produced 

water of appropriate quality would be used in drilling-mud systems and completion operations; this would 

reduce the volume of water to be disposed as well as the volume of fresh make-up water needed from 

other sources (water wells, etc.). Other produced-water disposal and re-use options, such as sub-irrigation 

drip systems, are being developed and would be considered by the BLM on a case-by-case basis. CBNG 

produced-water disposal considerations are discussed below. 

Avian mortality can be an issue in produced-water disposal pits due to salinity in the water and possible 

hydrocarbon contamination from condensate carryover. Typically, these facilities are fenced to preclude 

entry by wildlife. Flagging, netting, or other bird-deterrent devices are the most commonly used methods 

for achieving compliance with the Migratory Bird Treaty Act and WOGCC regulations. Concern 

continues as to the effectiveness of these deterrents; the BLM staff advocates the use of netting to 

preclude or reduce avian losses. 

Solid, non-hazardous wastes generated at drilling locations, man camps, and construction sites would 

continue to be handled as they are currently. Non-hazardous solid wastes would be accumulated in 

containers (dumpsters, trash cages, etc.) and hauled by commercial contractor to permitted disposal 

facilities. Alternative WDEQ-permitted disposal sites would need to be identified as local municipal 

solid-waste disposal facilities are experiencing capacity shortages and some are no longer accepting nonhousehold waste. The need to access alternative disposal sites located further from the development area 

4-224 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—WASTE AND HAZARDOUS MATERIALS 

results in waste being hauled longer distances at greater cost to the companies and risk to the traveling 

public. 

Industrial non-hazardous and/or exempt hazardous waste such as used glycol, antifreeze, lubricating oil, 

and batteries are recycled through third-party permitted companies or, as in the case of used lube oils, are 

legitimately recycled into crude-oil streams, when applicable and appropriate. 

In the rare instance that hazardous waste is produced it would be managed as required in the RCRA 

regulations. The BLM does not allow disposal of hazardous waste on federally managed lands; the 

WDEQ Solid and Hazardous Waste Disposal (WDEQ SHWD) program is the appropriate regulatory 

authority for these waste streams. Disposal of hazardous wastes in reserve pits is not allowed by any 

agency. 

Sanitary wastes would be transported by commercial contractors to permitted facilities. Alternatively, 

some permanent and long-term temporary facilities (such as man camps and field offices) would have 

approved septic systems in place. It can be anticipated that capacity concerns would arise relative to local 

municipal sanitary-waste disposal facilities. 

Commercial disposal facilities are typically located on privately owned lands and are permitted through 

the WOGCC and/or WDEQ. The current and anticipated levels of development activity and the resultant 

waste-disposal demand would result in a reduced design life for permitted facilities (municipal or 

commercial), necessitating the enlargement of existing sites or the permitting and construction of 

additional facilities. 

CBNG Produced-Water Management 

Coalbed natural gas (CBNG) development has different produced-water management issues when 

compared to conventional gas production. The greatest of these concerns are the volume of water 

produced and the quality of the water, both of which depend on the producing formation. Various 

produced-water management scenarios would be considered by the BLM in project-specific NEPA 

analysis if and when proposals are brought forward by CBNG proponents in the project area. 

Technological advances may make it possible to separate water and gas down-hole, thereby reducing the 

volume of water removed and managed on the surface. As with conventional produced water, CBNG 

water may be used for drilling and completion operations, if the water quality is appropriate. 

Hazardous Materials 

Hazardous materials are used in drilling, field development, construction, completion, and production 

operations. Implementation of the Proposed Action would result in the increase in hazardous materials 

being transported, stored, and used in the project area. IM WY-1994-081, IM WY-1997-011 and WY-94­

059 require that NEPA documents list and describe any hazardous or extremely hazardous materials that 

would be produced, used, stored, transported, or disposed of as a result of a proposed project, this 

compilation can be found in Appendix K, Hazardous Materials Management Summary. The 

quantities of hazardous substances used in the development or operation of wells would be kept in limited 

quantities on all sites and at the production facilities as needed for operations. None of the chemicals that 

would be used meet the criteria for being an extremely hazardous material/substance (40 CFR 355) or 

meet the quantities criteria per IM WY-93-344. Materials would not be stockpiled at well locations. 

Each Operator (and its subcontractors as applicable and appropriate) is required to comply with the 

following state and federal programs which are intended to reduce risk to human health and the 

environment from the use, storage, and transportation of hazardous materials. Implementation of the 

Proposed Action would require updating these program plans. Compliance with and implementation of 

the required plans would reduce the risk to human health and the environment from hazardous material 

releases in the project area. 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—WASTE AND HAZARDOUS MATERIALS 

	 A Hazard Communications Program (Haz-Com or Worker Right-to-Know) is required by OSHA 

and is intended to reduce the risk of occupational exposure to hazardous materials. 

	 A Community Right-to-Know (the Superfund Amendments and Reauthorization Act, or the 

Emergency Planning and Community Right-to-Know Act), required by the EPA, is intended to 

provide state and local emergency responders with information regarding the material hazards, 

location, and volumes of material that may be encountered when responding to an emergency.
 

	 Spill Prevention, Countermeasure, and Control Plans are required by the EPA and are intended 

to preclude the release of oils, such as diesel fuel, gasoline, crude oil, or condensate, into the waters 

of the United States; these plans must also provide response actions to be taken, and notifications to 

be made, in the event a release occurs. 

	 Emergency Response Plans are required by the BLM; these plans provide the BLM and operations 

personnel information about actions to be taken in the event an emergency situation (accidental fire, 

chemical or oil releases, well blow-out, etc.) should arise. These documents would be updated to 

include increased operations resulting from implementation of the Proposed Action. 

4.21.2.2 Alternative A: 100-Percent Vertical Drilling 

The impacts of implementing Alternative A would be the same as those resulting from the Proposed 

Action with the exception that drilling 100-percent vertical wells could result in a larger volume of 

drilling fluid being used in the development of the field. 

4.21.2.3 Alternative B: Enhanced Resource Protection 

The impacts of implementing Alternative B would be the same as those resulting from the Proposed 

Action except in the defined ERP areas. In these areas, stipulations for enhanced protection could result in 

concentration of buried reserve pit wastes in cluster development areas and could result in a reduction of 

vehicle traffic due to the consideration of pipelines to transport produced materials (condensate, produced 

water, etc.) out of the ERP area. 

4.21.2.4 Alternative C: Surface Disturbance Cap – High and Low Density Development Areas 

The impacts of implementing Alternative C would be the same as those resulting from the Proposed 

Action with the exception that the low-density drilling areas could realize a reduced volume of materials 

produced, transported, or disposed of in those areas of the project area compared to the high-density 

development areas. 

4.21.2.5 Alternative D: Directional Drilling 

The impacts of implementing Alternative D would be the same as those resulting from the Proposed 

Action with the exception that the requirement to drill all wells directionally from a single pad or existing 

location per section would likely extend the amount of time required to drill and complete each well 

therefore extending the time period over which development activities occur. While a slowing in project 

area development activities and associated waste generation may serve to extend the life of existing 

disposal facilities, the directional requirement may increase the volume of fluids needed for drilling 

operations but may also make recycling and re-use of these fluids more feasible. 

4.21.2.6 Alternative E: No Action 

Waste and hazardous material management activities would be greatly reduced because it is assumed that 

no new wells would be drilled. Some activities would still exist in support of ongoing production 

activities. 

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CHAPTER 4—ENVIRONMENTAL CONSEQUENCES—WASTE AND HAZARDOUS MATERIALS 

4.21.3 Impact Summary 

Currently authorized and approved actions, which would continue under the No Action alternative, are 

already exerting stress on the permitted and authorized disposal facilities proximal to the project area. 

Authorization of the Proposed Action or Alternatives A through C would result in further stress to the 

capacity of permitted waste management units used by the operating companies, including those used for 

management of solid waste, produced water, and drilling mud. Alternative D may serve to extend the life 

of some existing disposal facilities because the increase in directional drilling would result in greater 

recycling of drilling mud and other on-site materials. 

4.21.4 Unavoidable Adverse Impacts and Additional Mitigation Measures 

Implementation of the Proposed Action would result in an increase in hazardous materials being 

transported, stored, and used in the project area, and therefore in an increased risk of spills or other 

accidental releases of these materials. These increased risks would primarily occur during project 

development. Although the BLM discourages the use of produced water pits, they can be permitted when 

necessary. Avian mortality may occur in produced-water disposal pits due to salinity in the water and 

possible hydrocarbon contamination from condensate carryover, despite the use of netting. This increased 

risk would occur throughout the life of the project. 

The operating companies and their contractors are obligated to operate in compliance with applicable 

local, state, and federal regulations. The BLM recognizes these authorities and requires compliance with 

the applicable regulations. In addition to required mitigation measures as set forth in the Rawlins RMP 

and CD-C required Conditions of Approval and BMPs (Appendix C), the following mitigation measure 

would further reduce risks resulting from the generation of waste and the use and transport of hazardous 

materials: 

	 Consider cooperatively permitting and operating in-field disposal facilities for solid waste, produced 

water, drilling mud, and other activities as feasible. 

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5. CUMULATIVE IMPACTS 

Council on Environmental Quality (CEQ) regulations require an assessment of potential cumulative 

impacts. Cumulative impact is defined by those regulations at 40 CFR 1508.7 as: 

the impact on the environment which results from the incremental impact of the action when 

added to other past, present, and reasonably foreseeable future actions regardless of what 

agency (Federal or non-Federal) or person undertakes such other actions. Cumulative impacts 

can result from individually minor but collectively significant actions taking place over a period 

of time. 

Cumulative impacts for each affected resource are assessed in this section. The discussion of potential 

cumulative impacts assumes the successful implementation of the environmental protection and 

mitigation measures described in Appendix C and Chapter 4 of this EIS, as well as compliance with the 

Rawlins RMP and all applicable federal, state, and local regulations and permit requirements. The 

analysis of cumulative impacts addresses both potentially adverse and beneficial impacts. 

The cumulative impact analysis area for the CD-C project generally includes south-central Wyoming but 

is variable for each resource. No single geographic unit would serve as a cumulative impact analysis area 

for all resources. The Air Quality analysis, for example, analyzes cumulative impacts over an area that 

includes all of southwestern Wyoming and parts of Colorado, Utah, and Idaho. The Geology cumulative 

analysis, on the other hand, is concerned only with the CD-C project area itself. For the cumulative 

analysis in this draft EIS, each resource analysis includes a definition of the area considered in its 

cumulative impact analysis. 

The cumulative impact analysis has an estimated future timeframe of 45 years—the 15-year period of 

development plus the 30- to 40-year operational life of a producing well. As with the impact analysis 

area, the time frame for cumulative impact analysis will vary from one resource to another. Each resource 

analysis section describes the approximate time frame during which cumulative effects would occur. 

The “past, present, and reasonably foreseeable future actions” most commonly associated with the CD-C 

project area and south central Wyoming in general are grazing, transportation, and natural gas 

development. Livestock grazing—both sheep and cattle—began in the 1870s, continues today, and is 

expected to continue into the future. Sheep numbers have declined from their peak in the early part of the 

20th century but cattle numbers remain high. 

The area has been traversed by trails since humans first came to the area, and today includes major eastwest and north-south transportation and utility corridors used for roads, railroads, and pipelines. The 

Overland and the Cherokee Trails—historic passageways—cross the area. The first transcontinental 

railroad, the Union Pacific, came to the area in the 1860s and still operates today, with heavy freight 

traffic crossing east and west. The nation’s first transcontinental highway, the Lincoln Highway, was built 

in the same corridor as the railroad in the early part of the 20th century. It has been replaced by Interstate 

80 (I-80), which will remain a major east-west transportation route into the future. WY 789 and several 

county roads are the main north-south routes in the area. The Wamsutter hub is a major connection point 

for the many natural gas pipelines that traverse the area east-west and north-south. 

Natural gas development in the CD-C project area and the surrounding area has been ongoing since the 

1950s. The Wamsutter field, the first natural gas field in the area, was established in 1958. Since then, the 

rate of development has varied but has proceeded at the rate of about 200 wells per year since 2008. Prior 

development and existing activities within the project area are described in the introduction to Chapter 4, 

Environmental Consequences (Section 4.0.1). The 47,200 acres of new surface disturbance anticipated by 

the CD-C Natural Gas Development Project would be added to 56,647 acres of surface disturbance that 

has already occurred within the area. The CD-C project impacts for each of the resources and activities 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 5-1 
CHAPTER 5—CUMULATIVE IMPACTS 

discussed in Chapter 4 are described in the context of those disturbances and impacts that have already 

occurred in the project area. Those discussions will not be repeated here. There are other defined areas in 

south-central Wyoming—the Atlantic Rim and the Hiawatha project areas, for example—where natural 

gas has historically been produced and will continue to be produced. Those will be discussed in this 

section to the extent that they are relevant. Table 5.0-1 describes the principal natural gas projects that are 

ongoing or that are in planning. Map 5.0-1 shows energy development projects that are ongoing or in the 

planning stage. 

In addition to natural gas activities, Table 5.0-1 also describes reasonably foreseeable future wind energy 

development projects, mining activity, and major electric transmission lines and industrial development 

projects. 

5-2 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
CHAPTER 5—CUMULATIVE IMPACTS 

Table 5.0-1. Ongoing and Reasonably Foreseeable Future Actions (RFFAs) 

Project Proponent Location County Development Schedule 

Natural Gas Atlantic Rim Natural Gas Field Development 

Anadarko Petroleum Corporation and others 

East of and adjacent to CD-C project area Carbon 2007–2027 

Beaver Creek Natural Gas Development Project Devon 9 miles southeast of Riverton Fremont 2013–2023 

Bitter Creek Shallow Oil and Gas Project 

Infinity / Yates Petroleum 

30 miles east of Rock Springs between Bitter Creek and Point of Rocks 

Sweetwater 2005–2009 

Desolation Flats Natural Gas Development Project Marathon Oil and others Southwest of and adjacent to CD-C project area Sweetwater/Carbon 2004–2024 

Gun Barrel, Madden-Deep, Iron Horse (GMI) Natural Gas Development Project 

EnCana Oil & Gas, Burlington Resources and Noble Energy 

60 miles west of Casper Fremont/ Natrona 2013–2043 

Hiawatha Regional Energy Development Project 

Questar/ Wexpro 

65 miles southeast of Rock Springs 

Sweetwater/Moffat 

CO 2013–2043 

LaBarge Gas Exploration and Development Project 

EOG Resources, Inc and others. 

65 miles northwest of Rock Springs 

Lincoln/ 

Sublette 2013–2023 

Luman Rim Yates Petroleum and others Northwest of and adjacent to CD-C project area Sweetwater 2011–2021 

Moxa Arch Area Infill Gas Development Project BP America and others Northeast of Fort Bridger Uinta/Lincoln/ Sweetwater 2013–2043 

Normally Pressured Lance Natural Gas Development Project 

EnCana and others Immediately southwest of the Jonah Field Sublette 2014–2026 

Table Rock Unit Oil and Gas Development Chevron U.S.A. 40 miles east of Rock Springs (partly in CD-C) Sweetwater 2013–2027 

Wind Energy Bridger Butte Wind Energy Project 

Bridger Butte Wind Power LLC West of Fort Bridger Uinta 2021– 

Chokecherry and Sierra Madre Wind Energy Project 

Power Company of Wyoming South of Rawlins Carbon 2012–2015 

Sweeney Ranch Wind Park Sweeney Ranch Wind Park, LLC 15 miles southeast of Rock Springs Sweetwater 2013–2016 

White Mountain Wind Farm Teton Wind Near Rock Springs Sweetwater 2012–2018 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
CHAPTER 5—CUMULATIVE IMPACTS 

Table 5.0-1. Ongoing and Reasonably Foreseeable Future Actions, continued 

Project Proponent Location County Development Schedule 

Wind Energy, continued Quaking Aspen Mountain Wind Farm 

Evergreen Wind Power Partners, LLC 

11 miles SE of Rock Springs Sweetwater Unknown 

Transmission Lines Gateway West Transmission Line Project 

Idaho Power and Rocky Mountain Power Companies 

Glenrock, Wyoming to Melba, Idaho 

Converse/ Albany/ 

Carbon/ Sweetwater 

and west 

2014–2018 

Gateway South Transmission Line Project 

Rocky Mountain Power Company 

Medicine Bow, Wyoming to Mona, Utah 

Converse/ Albany/ 

Carbon/ and 

southwest 

2017–2020 

TransWest Express Transmission Line Project 

TransWest Express (Anschutz subsidiary) 

Sinclair, Wyoming to southern Nevada 

Carbon and 

southwest 2013–2016 

Mining Lost Creek In Situ Uranium Project 

UR Energy (Lost Creek ISR LLC) 

15 miles southwest of 

Bairoil Sweetwater 2011-2024 

Bridger Mine Expansion 

Idaho Energy Resource Company/Pacific Minerals 

North of Point of Rocks Sweetwater 2011–2031 

Other Medicine Bow Fuel & Power Coal-to-Liquids Project 

Medicine Bow Fuel & Power South of Medicine Bow Carbon 2014– 

5-4 Continental Divide-Creston Natural Gas Development Project D
CHAPTER 5—CUMULATIVE IMPACTS 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

Map 5.0-1. Reasonably foreseeable future actions in the cumulative impact analysis area 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 5-5 
CHAPTER 5—CUMULATIVE IMPACTS 

 PHYSICAL ENVIRONMENT 

5.1 GEOLOGY 

The cumulative impact analysis area (CIAA) for geology is the CD-C project area. Geologic resources are 

not expected to be impacted by activities that occur outside the project area nor would implementation of 

CD-C project activities have impact outside the area. Cumulative impacts would be limited to past and 

ongoing oil and gas extraction, grazing, and transportation activities within the project area. Geological 

resources have not been significantly affected by past and continuing activities in the project area and are 

not expected to be notably affected by any future activities if mitigation measures described in Appendix 

C are implemented. 

5.2 PALEONTOLOGIC RESOURCES 

The CIAA for paleontology is the CD-C project area. Paleontological resources are not expected to be 

impacted by activities that occur outside the project area. Cumulative impacts would be limited to past 

and ongoing oil and gas extraction, grazing, and transportation activities within the project area. 

Paleontological resources have not been significantly affected by past and continuing activities in the 

project area and are not expected to be notably affected by any future activities if mitigation measures 

described in Appendix C and Section 4.2.5, Unavoidable Adverse Impacts and Additional Mitigation 

Measures, are implemented. 

5.3 SOILS 

The CIAA for soils is the CD-C project area. Past, present, and future actions would incrementally 

increase soil disturbances and soil productivity for the lifetime of development and gas production in the 

project area, approximately 45 years. The cumulative losses for soil resources would occur due to 47,200 

acres of new surface disturbance in addition to 60,176 acres of historic surface disturbance related to 

natural gas development and other activities. The increased surface disturbance for the Proposed Action 

would represent a 78-percent increase relative to that for historic development, although the impacts 

would be mitigated by successful implementation of interim and final reclamation during the life of the 

project. The 47,200 acres of new disturbance under the Proposed Action is approximately 44 percent of 

the cumulative disturbance for the project area soils. 

Impacts to soils in the project area related to the Proposed Action and various alternatives are described in 

Section 4.3.3 of the EIS. Post-reclamation disturbances for the Proposed Action and various alternatives 

would be relatively low and successful reclamation would reduce the cumulative impacts to the soil 

resource that may result from the Proposed Action or the alternatives. Impacts to soil productivity, 

vegetation, and surface water would be more severe during development and production and would 

diminish during final reclamation and the post-reclamation phase of the project. Implementation of Best 

Management Practices (BMPs) to reduce erosion and sedimentation and promote revegetation would be 

used to reduce cumulative impacts. 

Cumulative impacts to project area soils include past, present, and future actions that would affect 

surface-water quality due to erosion and sediment discharge, and increased surface disturbances that 

reduce soil productivity prior to successful reclamation. The geographic area of soils-related cumulative 

impacts includes surface disturbances within the project area in addition to the water quality related 

impacts. 

The northern 70 percent of the project area is located in the Great Divide Basin, a closed basin which is 

bounded by the Continental Divide. Impacts from erosion and sediment within the basin are generally low 

and dependent upon localized soils and terrain. Since surface water would not discharge outside of the 

5-6 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
 

CHAPTER 5—CUMULATIVE IMPACTS 

closed basin, impacts from erosion and sediment would not affect any other watershed. Future actions that 

would result in cumulative impacts within the Great Divide Basin include the Luman Rim Natural Gas 

Development located northwest of and adjacent to the project area. 

The southern portion of the project area is primarily drained by Muddy Creek and its tributaries which are 

part of the Little Snake River Basin. The Muddy Creek Sub-basin has been historically impacted and is 

listed in the 2010 Wyoming 303(d) List as either not supporting or threatened for aquatic life, non-game 

fish and cold-water game fish (WDEQ 2010). Unstable stream channels and loss of riparian function have 

occurred throughout the basin due to season-long riparian grazing and accelerated erosion associated with 

oil and gas activities. In upper Muddy Creek the Little Snake River Conservation District (LSRCD), 

BLM, landowners, grazing permittees, Wyoming Game and Fish (WGFD), and other stakeholders have 

been involved in Coordinated Resource Management since 1992 including several Section 319 watershed 

improvement projects. These projects have included upland water development, cross fencing, and 

vegetation and grazing management. Deferred grazing has also been implemented in the Grizzly Wildlife 

Habitat Management Area to promote restoration of watershed function. LSRCD and WGFD data 

indicate that improvement to stream stability, aquatic habitat and riparian areas has resulted from both of 

these projects and several reaches in Muddy Creek, Littlefield Creek, and McKinney Creek are meeting 

their aquatic life uses and have been removed from the 303(d) list. These projects are located in the Upper 

Muddy Creek Drainage outside of the project area. 

The LSRCD and other stakeholders have also implemented another watershed improvement project to 

address physical degradation of the Muddy Creek stream channel, which threatens aquatic life-use 

support. This project is located along Muddy Creek on the west side of WY 789 in the project area and 

includes wetlands development, reestablishment of the floodplain and irrigation water management. This 

project has resulted in improving trends in riparian condition and bank stability. 

Future actions that would result in cumulative impacts to the Proposed Action within the Muddy Creek 

Sub-basin include the Desolation Flats Natural Gas Development Project located adjacent and southwest 

of the project area, and the Atlantic Rim Natural Gas Field Development located east of and adjacent to 

the project area. 

5.4 WATER RESOURCES 

The CIAA for water resources includes two components: (1) an analysis of cumulative impacts within the 

CD-C project area and (2) an analysis of cumulative impacts on portions of the watersheds that are 

associated with the CD-C project area. The cumulative surface water impacts analysis area includes 

portions of the White-Yampa, Great Divide, and the Upper Green drainage basins. The cumulative 

groundwater impact analysis area includes portions of the Green River, Great Divide, and Washakie 

structural basins, the Rock Springs and Rawlins uplifts, and the Wamsutter Arch. Cumulative impacts 

include water resource impacts from past, present, and reasonably foreseeable future oil and gas 

developments, agriculture (irrigated crops, livestock grazing, and ranch management), recreational 

activities/vehicular traffic, and other mining and industrial activities. 

5.4.1 Cumulative Impacts Common to the CD-C Project-Specific and Watershed 

Analysis Areas 

Surface Water. All action alternatives would result in increased natural gas development in the CD-C 

project area, with the difference between alternatives being the magnitude of disturbance. Including the 

CD-C project, there are 12 currently operating or planned oil and gas development projects within the 

CD-C larger watershed analysis area. The projects with the greatest potential to contribute to cumulative 

impacts to surface water resources would be the CD-C project and the Atlantic Rim Natural Gas 

Development Project. These projects are adjacent to Muddy Creek, which as discussed below, is under 

special protection by the State of Wyoming. Historic development in the project area accounts for 60,176 

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CHAPTER 5—CUMULATIVE IMPACTS 

acres of initial disturbance and 17,663 acres of long-term disturbance. Total historic development in the 

watershed analysis area has not been calculated. The Proposed Action and the alternatives would add 

disturbance of between 36,499 acres (Alternative D) and 61,696 acres (Alternative A). The long-term 

disturbance would range from 14,952 to 24,133 acres. The main cumulative impacts to surface-water 

resources from oil and gas development would be brought about by contamination of surface water from 

both authorized and accidental surface discharge of fluids and the impacts (including sediment loading) 

from surface disturbance related to project development/maintenance. These cumulative impacts would 

be greatest within the CD-C analysis area but the contamination of surface water and off-site 

sedimentation would extend downstream of the CD-C watershed analysis area. As part of the Atlantic 

Rim project, Upper Muddy Creek is currently monitored for sediment delivery from eroding streambanks, 

measurement of habitat features and stream geomorphology, and measurement of sediment concentrations 

and other water quality parameters. 

Agriculture (irrigated crops, livestock grazing, and ranch management) and other natural resource uses 

within the cumulative impact analysis areas would result in increased surface runoff, accelerated erosion, 

and off-site sedimentation that would cause channel instability and degradation of surface-water quality. 

Because livestock tend to concentrate around available sources of water (stock reservoirs, stock tanks 

associated with water wells, and flowing streams) there would be localized effects in these areas, which 

could lead to greater erosion where anthropogenic surface disturbances and livestock concentration areas 

overlap. Two portions of Muddy Creek, which is within the White-Yampa watershed (Map 3.4-1), are 

now listed on the State 303(d) list of Impaired or Threatened Waterbodies due to habitat alteration, 

primarily due to livestock grazing (WDEQ 2012) and exacerbated by oil and gas development. The Little 

Snake River Conservation District (LSRCD) has been working through a Coordinated Resource 

Management (CRM) process with the BLM, landowners, grazing permittees, WGFD, and other 

stakeholders since 1992 to address these water quality and riparian habitat problems. As part of the CRM 

process, LSRCD has managed several Section 319 watershed improvement projects in the upper Muddy 

Creek drainage. According to WDEQ, the projects have resulted in considerable improvement to stream 

stability, aquatic habitat and riparian health, especially in the upper Muddy Creek tributaries (WDEQ 

2012). While the CRM process is no longer formally in place, the beneficial effects are still being 

realized. Although not agricultural in nature, accelerated erosion associated with oil and gas activities 

within the Muddy Creek sub-basin has been identified as having a role in exacerbating the degradation of 

lower Muddy Creek. Surface water impacts would be considered significant for at least one surface-water 

significance criterion through cumulative impacts if the Proposed Action or any of the action alternatives 

were selected. Cumulative surface water impacts would not be considered significant for Alternative E. 

Recreational activities and vehicular travel would have minimal effects on surface water, but could be 

more pronounced in localized areas due to off-road travel and additional access provided by resource 

development. Off-road travel in drainage areas would cause local impacts to surface waters. Impacts 

could be more significant where there is continuous federal land and the project improves or creates new 

access. Recreational activities and off-road travel are not expected to have significant effects on surfacewater resources and would not contribute to the significance impacts discussed in Section 4.4.4. 

Other industrial activities (i.e., mining, wind energy development, and construction of power transmission 

lines) would impact surface-water quality in localized areas within the cumulative impact area. The 

proposed Gateway West, Gateway South, and TransWest Express transmission line projects would cross 

the cumulative impact analysis areas and would have the potential to affect surface water during 

construction, operation, and decommissioning of the projects, particularly where the transmission 

corridors cross drainages. The BLM is the lead federal agency for the NEPA process for these proposed 

projects. 

Groundwater. As discussed in Section 5.0, natural gas development in the project area and the 

surrounding region has been ongoing since the 1950s. Since initiation of drilling, over 4,400 natural-gas 

wells have been drilled. All of the action alternatives would result in the same number of new wells 

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CHAPTER 5—CUMULATIVE IMPACTS 

drilled (8,950 natural gas and 30 injection), with the difference being the number of well pads and the 

extent of required access roads and pipelines needed for resource development. Cumulative groundwater 

impacts would occur during the removal of groundwater; from improper drilling operations; from 

accidental releases of fluids (spills) associated with drilling and fracturing operations, produced water, 

and other hazardous liquids to soils and surface-water systems; and through subsurface disposal 

(injection) of produced water. These impacts are the same as the project specific impacts described in 

Section 4.4.4. Cumulative groundwater impacts are not expected to be significant and would not 

contribute to the significance impacts discussed in Section 4.4.4. 

5.4.2 Cumulative Impacts within the CD-C Project Area 

Surface Water. The types of cumulative surface-water impacts would be the same as those discussed in 

Section 5.4.1. Disturbance related to current oil and gas development has already occurred. Cumulative 

impacts, particularly from the CD-C and Atlantic Rim projects, would exacerbate current degradation on 

Muddy Creek. Since the CD-C project would be the largest contributor to cumulative impacts, 

successfully utilizing BMPs and COAs listed in Appendix C would reduce the potential for adding to 

cumulative impacts. Surface water impacts would be considered significant for at least one surface-water 

significance criteria through cumulative impacts if the Proposed Action or any of the action alternatives 

were selected. Surface water impacts would not be considered significant for Alternative E. 

Groundwater. The types of cumulative groundwater impacts would be the same as those discussed in 

Section 5.4.1. Using the available estimates of water use included in the NEPA analyses of projects still 

in development within the project area, the total cumulative water demand over the lives of the projects 

would be 40,470 ac-ft (BLM 2004, 2005e, 2006a, 2007f, 2010d, and 2011b). This amount is 

approximately 0.4 percent of the estimated volume of producible groundwater available (9.67 million acft) in the Tertiary-age aquifers underlying the project area (calculated from information in Cleary et al. 

2010). Available water is also found in Quaternary, Upper and Lower Cretaceous, and Jurassic age 

aquifers. Fisk (1967) estimated that the amount of moderately good-quality groundwater within the Great 

Divide Structural Basin was 500 million ac-ft and 300 million ac-ft within the Washakie Structural Basin. 

The combined annual recharge for the Great Divide and Washakie structural basins has been estimated at 

11,300 ac-ft (Fisk 1967), which is well above the estimated annual 2,700 ac-ft. of water removed for 

development of the six projects. Cumulative groundwater impacts are not expected to be significant. 

5.4.3 Cumulative Impacts within the Watershed Area 

Surface Water. The types of cumulative surface-water impacts would be the same as those discussed in 

Section 5.4.1. Surface water impacts would be considered significant for at least one surface-water 

significance criteria through cumulative impacts if the Proposed Action or any of the action alternatives 

were selected. Surface water impacts would not be considered significant for Alternative E. 

There are two existing large-scale coal mines (Black Butte and Jim Bridger) located within the watershed 

analysis area. Impacts to surface water from mining activities include increases in runoff, turbidity, and 

sedimentation within the project area due to disturbances to vegetation and soil resources. Permit 

requirements and compliance with rules and regulations associated with surface mining are under the 

jurisdiction of the WDEQ with Office of Surface Mining Reclamation and Enforcement (OSM) oversight. 

These mines are not expected to contribute measurably to the significance impacts discussed in Section 

4.4.4. 

The existing Sweetwater uranium mill (currently not operational) and the proposed Lost Creek/Lost 

Soldier in situ uranium recovery (ISR) projects are located in the Great Divide Basin, just north of the 

project area. These projects have the potential to impact surface water during construction/operation 

through ground disturbance and vegetation removal or if leachate is accidentally discharged into surface 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 5-9 
CHAPTER 5—CUMULATIVE IMPACTS 

waters. The Nuclear Regulatory Commission (NRC) oversees uranium source and byproduct material 

license applications and the WDEQ has authority over permits to mine for uranium operations. 

Wind-energy development and industrial development projects are under the jurisdiction of the Wyoming 

Industrial Siting Council and boards of county commissioners (through Wyoming HEA No. 0064). Windenergy development projects have the potential to affect surface water during construction. These projects 

could result in contamination of surface water, increased surface runoff, erosion, and off-site 

sedimentation that would cause channel instability and degradation of surface-water quality, particularly 

where the development impacts drainage channels. The proposed Chokecherry/Sierra Madre Wind 

Energy Project is the nearest wind-energy development project and is located approximately 7 miles east 

of the project area in Carbon County. The proposed Sweeney Ranch Wind Park is located approximately 

18 miles west of the project area in Sweetwater County and the Middlewood Wind Power Project is 

located approximately 22 miles east of the project area in Carbon County. 

Downstream demands for water in the Green River and Little Snake River drainages would continue to 

influence water management in the Upper Green and White-Yampa basins, respectively. According to the 

2010 Green River Management Plan, which provides a 50-year projection of water use in watersheds that 

include the Upper Green and White-Yampa basins in Wyoming, approximately 680,000 ac-ft/year would 

be depleted from the Basin from all sources (agriculture, municipal, domestic, industrial, recreational, 

environmental, and evaporation) under a moderate growth scenario by 2060 (Wyoming Water 

Development Office 2011). Wyoming's estimated 2060 allocation of the Upper Colorado River water 

under the Colorado River Compact totals approximately 847,000 ac-ft/year, which would mean that 

approximately 167,000 (847,000–680,000) ac-ft/year would remain under the Compact allocation 

(Wyoming Water Development Office 2011). No surface water would be used for any part of the well 

drilling or construction process so the proposed project would not contribute to surface-water depletion 

within the Colorado River system. 

According to the WDEQ-WQD database, there are currently 23 active coalbed natural-gas (CBNG), oiland-gas-related, industrial, or coal mining Wyoming Pollutant Discharge Elimination System (WYPDES) 

discharge permits in the cumulative watershed area (WDEQ-WQD 2011). The Proposed Action does not 

include plans for any surface discharge of produced water. It is therefore assumed that all water produced 

would be injected or evaporated and no additional discharge permits would be necessary for the surface 

disposal of produced water. Permitting for surface discharge of produced water related to federal land or 

minerals would require a separate NEPA evaluation. 

Groundwater. The types of cumulative groundwater impacts would be the same as those discussed in 

Section 5.4.1. Using the available estimates of water use included in the NEPA analyses of oil and gas 

projects that are still in development in the watershed analysis area, the total cumulative water demand 

from oil and gas development would be approximately 46,000 ac-ft over the lives of the projects (BLM 

2004, 2005e 2006a, 2007f, 2009b, 2010d, 2011b, and 2011c). This amount is approximately 0.1 percent 

of the estimated volume of producible groundwater available (75.2 million ac-ft) in Tertiary-age aquifers 

underlying the Greater Green River Basin (Cleary et al. 2010). Available water is also found in 

Quaternary, Upper and Lower Cretaceous, and Jurassic age aquifers. Fisk (1967) estimated that the 

amount of moderately good-quality groundwater within the Great Divide Structural Basin was 500 

million ac-ft and 300 million ac-ft within the Washakie Structural Basin. The combined annual recharge 

for the Great Divide and Washakie structural basins has been estimated at 11,300 ac-ft (Fisk 1967), which 

is much greater than the estimated annual demand of 3,000 ac-ft removed for development. 

The Black Butte and Jim Bridger coal mines are located within the watershed analysis area. Impacts of 

mining, including cumulative hydrologic impacts, are regulated by WDEQ/LQD with oversight by OSM. 

The mine pits/active workings would be completely dewatered, which would result in drawdown of 

formation aquifers in the vicinity of the mining activities. These mines are not expected to contribute 

measurably to contribute measurably to the significance impacts discussed in Section 4.4.4 since the 

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CHAPTER 5—CUMULATIVE IMPACTS 

extent of drawdown would be limited due to the lack of lateral continuity of the water-bearing units in the 

affected formation. 

The Sweetwater Mill project has the potential to impact groundwater through accidental discharge from 

the existing tailings impoundment; the impoundment is reported to have leaked several times between 

1980 and 1984. Contamination did not leave the site but did enter the upper aquifer. Subsequent remedial 

actions are reducing the extent of contaminated groundwater. Contaminated soil is being excavated and 

placed into the existing tailings impoundment and contaminated groundwater is being extracted and 

placed into the existing tailings impoundment (NRC 2011). The proposed Lost Creek/Lost Soldier project 

will impact groundwater during recovery and injection well construction and completion or from spills 

and leaks, excursions, wellfield development drilling, or deep well injection. The NRC oversees uranium 

source and byproduct material license applications and the WDEQ has authority over permits to mine for 

uranium operations. 

5.5 AIR QUALITY 

The CAMx model was used to quantify the impacts to regional air quality and AQRVs resulting from the 

CD-C project, other proposed oil and gas developments in the study area (Reasonably Foreseeable 

Development, or RFD) and all other regional emissions sources within the study area. Since the CAMx 

photochemical grid model was used in the far-field air quality analysis, the impacts of emissions sources 

outside the Southwest Wyoming study area were also included via transport of these emissions and their 

chemical reaction products into the study area. 

CAMx was used to assess the impacts to both ambient air concentrations and AQRVs from air pollutant 

emissions of CO, NOx, SO2, PM10, PM2.5, and VOC expected to result from CD-C Project emissions 

combined with regional emissions throughout the study area. The cumulative study considers 2008 as a 

baseline year for emissions and assesses impacts to air quality at peak project year emissions levels that 

are expected to occur in year 2022. Air quality impacts are assessed for year 2022, and AQRV impacts 

are assessed for 2022 and relative to year 2008 levels. The CAMx model was run with both 2008 and 

2022 emissions (including the CD-C project area emissions) for two years (2005 and 2006) of 

meteorological data. 

The cumulative assessment was performed using the Proposed Action emissions. The cumulative impacts 

resulting from all project development alternatives (Alternatives A through D) would be similar to 

impacts of the Proposed Action. Under Alternative E (No Action) there would be no cumulative impact to 

air quality or AQRVs since there would be no new development associated with the CD-C project. 

5.5.1 Emissions from Regional Sources 

Maximum emissions from all RFD sources within the study area were estimated. RFD is defined as (1) 

air emissions from the undeveloped portions of authorized NEPA projects, and (2) air emissions from 

not-yet-authorized NEPA projects (if emissions are quantified when modeling commences). RFD 

information from not-yet-authorized projects was obtained from the BLM and was based on ongoing air 

quality analyses for NEPA projects. 

Full development of proposed projects inventoried as RFD may or may not coincide with full 

development of the CD-C project. As a result, the assumption that all RFD are fully developed during the 

maximum year of CD-C project development results in some conservatism in the cumulative impact 

analysis. A listing of RFD projects which were included in this study, as defined in the paragraph above, 

is presented in Table 5.5-1. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 5-11 
 

 

CHAPTER 5—CUMULATIVE IMPACTS 

Table 5.5-1. RFD emissions within the study area. 

Project Modeled Pollutant Emissions (tpy) 

NOx VOC CO SO2 PM10 PM2.5 

Moxa Arch Existing Project 1,519 16,444 1,152 1 212 75 

Moxa Arch Preferred Alternative 1,257 2,099 2,002 0 582 131 

Moxa Arch ROD Wells 63 166 123 0 30 6 

Beaver Creek 68 228 60 1 102 11 

Eagle Prospect 409 196 395 5 97 29 

Gun Barrel-Madden Deep-Iron Horse 850 3,700 2,085 1 1291 160 

Pinedale 1,381 2,286 1,250 53 79 79 

Hiawatha Proposed Action 2,157 15,904 915 85 3,398 398 

Jonah 1,099 2,705 686 62 28 28 

Tables 5.5-2 and 5.5-3 summarize the complete regional emission inventories for the study area (the 4­

km modeling domain shown in Map 4.5-1). The tables report the modeled emissions of CO, NOx, SO2, 

PM10, and PM2.5, and total organic gas (TOG), for each region and emissions source category. The CD-C 

project emissions that are included in these tables are for the Proposed Action. Emissions tables are 

presented for 2008, 2022 and the difference between the 2022 future year and 2008 baseline inventories 

(2022–2008). For each year and for the 2022–2008 difference, emissions are reported for the 2006 

meteorological year. (Emissions for both the 2005 and 2006 scenarios are reported in Section 2 of the 

AQTSD.) 

Tables 5.5-2 and 5.5-3 contain emissions for all portions of Wyoming, Colorado, Utah, and Idaho that 

are within the 4-km modeling domain that comprised the study area. The five counties in Southwest 

Wyoming covered by the detailed oil and gas emission inventory (described in Section 2 of the AQTSD) 

are broken out separately from the rest of Wyoming in all of the tables. Oil and gas emissions are broken 

down into drilling, compressor engine, and production emissions. In Table 5.5-3, there are zero entries 

for the 2022-2008 change in biogenic or fire emissions because the 2006 actual emissions were used in 

both 2008 and 2022 emission scenarios. The only trona facilities in the study area are located in 

Wyoming; therefore, trona emissions for Colorado, Idaho, and Utah are zero. 

Table 5.5-3 shows that on-road mobile emissions would decrease for all pollutants in all areas between 

2008 and 2022 due to increasingly stringent emissions controls. Non-road emissions also decline for all 

areas for all pollutants except CO. This would occur because of the implementation of non-road engine 

tier standards that require increasingly cleaner-burning engines as fleet turnover occurs. Non-oil and gas 

area source emissions would increase for all pollutants within Wyoming going from 2008 to 2022. NOx 

and total organic gas (TOG) emissions increase for non-oil and gas area source emissions for all four 

states in 2022 relative to 2008. This is reasonable because future area source emissions are often projected 

using population changes as a basis for calculating changes in emissions. 2008 to 2022 changes in 

electricity generating units (EGU) emissions and non-EGU (NEGU) point source emissions vary by state 

and pollutant. 

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CHAPTER 5—CUMULATIVE IMPACTS 

Table 5.5-2. Regional emissions summary table for the 2022 future year (tpy) 

STATE Source Category 

Oil and Gas Area Onroad Offroad EGU NEGU Natural 

CO 

Colorado 799 2,519 15,246 8,426 1,735 67 12,535 

Idaho 411 535 2,070 4,583 0 17,670 20,513 

Utah 41,451 1,960 16,338 11,877 1,469 109 8,608 

Wyoming 27,624 14,596 56,568 37,856 3,816 14,182 82,627 

Carbon Co, Wyoming 829 856 

56,568 

3,713 135 1,552 3,131 

Lincoln Co, Wyoming 711 2,129 2,270 819 380 297 

Sublette Co, Woming 1,885 716 2,828 0 389 16,203 

Sweetwater Co, Wyoming 2,731 1,801 4,670 2,498 11,418 4,076 

Uinta Co, Wyoming 534 1,307 2,877 330 99 803 

Wyoming (rest) 1,797 7,789 21,498 33 345 58,117 

RFD 8,665 0 0 0 0 0 0 

CD-C Project 10,474 0 0 0 0 0 0 

NOx 

Colorado 1,291 177 776 849 24,166 89 677 

Idaho 152 402 128 478 0 2,378 864 

Utah 13,706 244 857 1,272 8,386 112 347 

Wyoming 30,556 8,261 3,590 15,066 39,072 12,748 2,911 

Carbon Co, Wyoming 2,297 620 

3,590 

3,149 153 478 111 

Lincoln Co, Wyoming 1,820 1,187 1,278 10,880 1,662 16 

Sublette Co, Woming 2,476 130 330 0 469 574 

Sweetwater Co, Wyoming 4,748 1,478 5,444 27,338 9,601 207 

Uinta Co, Wyoming 733 447 1,691 667 120 26 

Wyoming (rest) 2,962 4,398 3,173 34 419 1,977 

RFD 8,805 0 0 0 0 0 0 

CD-C Project 6,717 0 0 0 0 0 0 

SO2 

Colorado 15 83 10 3 7,002 5 16 

Idaho 0 15 2 1 0 3,921 97 

Utah 731 142 11 3 1,645 10 48 

Wyoming 5,602 7,458 45 19 22,374 23,588 556 

Carbon Co, Wyoming 60 394 

45 

3 246 3,354 8 

Lincoln Co, Wyoming 1,543 1,838 1 6,357 65 1 

Sublette Co, Woming 4 63 1 0 240 117 

Sweetwater Co, Wyoming 267 590 5 15,771 14,592 2 

Uinta Co, Wyoming 98 237 2 0 876 7 

Wyoming (rest) 3,419 4,337 7 0 4,461 422 

RFD 208 0 0 0 0 0 0 

CD-C Project 4 0 0 0 0 0 0 

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CHAPTER 5—CUMULATIVE IMPACTS 

Table 5.5-2. Regional emissions summary table for the 2022 future year (tpy), continued 

STATE Source Category 

Oil and Gas Area Onroad Offroad EGU NEGU Natural 

TOG 

Colorado 20,767 1,850 830 1,147 183 323 54,199 

Idaho 44 5,214 120 1,174 0 7 32,486 

Utah 1,060,778 2,668 861 2,300 114 1,673 13,407 

Wyoming 1,473,030 22,192 3,257 4,261 683 25,291 89,977 

Carbon Co, Wyoming 27,263 

22,192 3,257 4,261 12,495 25,291 

7,497 

Lincoln Co, Wyoming 75,250 878 

Sublette Co, Woming 159,573 19,459 

Sweetwater Co, Wyoming 313,200 14,911 

Uinta Co, Wyoming 8,310 113 

Wyoming (rest) 209,909 47,120 

RFD 379,714 0 0 0 0 0 0 

CD-C Project 299,812 0 0 0 0 0 0 

PM10 

Colorado 37 10,544 37 75 592 3,504 261 

Idaho 0 9,454 6 62 0 0 1,513 

Utah 469 7,134 41 112 887 267 756 

Wyoming 8,929 73,379 164 610 3,399 13,320 9,139 

Carbon Co, Wyoming 91 8,616 

164 

118 3 683 131 

Lincoln Co, Wyoming 72 3,323 53 1,457 440 16 

Sublette Co, Woming 22 5,276 30 0 0 1,915 

Sweetwater Co, Wyoming 80 11,445 184 1,939 12,086 30 

Uinta Co, Wyoming 3 1,461 62 0 1 110 

Wyoming (rest) 90 43,256 163 0 111 6,936 

RFD 5,818 0 0 0 0 0 0 

CD-C Project 2,753 0 0 0 0 0 0 

PM2.5 

Colorado 37 1,191 18 70 0 0 233 

Idaho 0 206 3 58 0 0 1,311 

Utah 460 772 21 106 561 169 675 

Wyoming 1,951 6,410 83 611 4,114 1,776 8,377 

Carbon Co, Wyoming 91 940 

83 

118 0 111 118 

Lincoln Co, Wyoming 72 560 53 821 2 15 

Sublette Co, Woming 22 532 30 0 0 1,768 

Sweetwater Co, Wyoming 80 1,313 184 3,295 1,658 24 

Uinta Co, Wyoming 3 298 62 0 0 101 

Wyoming (rest) 90 2,768 164 0 6 6,351 

RFD 916 0 0 0 0 0 0 

CD-C Project 677 0 0 0 0 0 0 

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CHAPTER 5—CUMULATIVE IMPACTS 

Table 5.5-3. Regional 2022-2008 emissions difference summary table (tpy) 

STATE Source Category 

Oil and Gas Area Onroad Offroad EGU NEGU Natural 

CO 

Colorado -230 71 -3,116 495 379 9 0 

Idaho 149 48 -510 38 0 6,760 0 

Utah 23,068 -14 -3,260 -335 1,043 -535 0 

Wyoming 15,311 754 -16,099 1,512 478 -3,191 0 

Carbon Co, Wyoming -343 -1 

-16,099 

-136 135 902 0 

Lincoln Co, Wyoming -434 3 -263 241 52 0 

Sublette Co, Woming -2,543 -8 -572 -20 305 0 

Sweetwater Co, Wyoming -447 6 223 -227 -3,375 0 

Uinta Co, Wyoming -57 -6 -127 330 -4 0 

Wyoming (rest) -5 759 2,387 19 -1,070 0 

RFD 8,665 0 0 0 0 0 0 

CD-C Project 10,474 0 0 0 0 0 0 

NOx 

Colorado -422 25 -959 -396 -4,523 4 0 

Idaho -1,129 63 -173 -197 0 445 0 

Utah 2,216 30 -1,067 -499 1,177 -1,017 0 

Wyoming 8,921 1,126 -4,999 -4,028 544 -2,065 0 

Carbon Co, Wyoming -319 55 

-4,999 

-950 153 -144 0 

Lincoln Co, Wyoming -449 147 -453 -3,614 247 0 

Sublette Co, Woming -5,134 9 -177 -204 365 0 

Sweetwater Co, Wyoming -632 125 -1,551 3,535 -1,584 0 

Uinta Co, Wyoming -60 38 -564 667 74 0 

Wyoming (rest) -7 752 -334 7 -1,022 0 

RFD 8,805 0 0 0 0 0 0 

CD-C Project 6,717 0 0 0 0 0 0 

SO2 

Colorado -5 3 -1 -30 -792 1 0 

Idaho -1 1 0 -17 0 -4,997 0 

Utah 550 -2 -1 -42 672 4 0 

Wyoming 100 1,039 -7 -387 -21,604 8,017 0 

Carbon Co, Wyoming 0 62 

-7 

-82 246 2,252 0 

Lincoln Co, Wyoming -4 343 -36 -16,413 -129 0 

Sublette Co, Woming -132 2 -13 0 224 0 

Sweetwater Co, Wyoming -1 29 -135 -5,436 2,195 0 

Uinta Co, Wyoming 0 8 -46 0 862 0 

Wyoming (rest) 26 595 -75 -1 2,613 0 

RFD 208 0 0 0 0 0 0 

CD-C Project 4 0 0 0 0 0 0 

TOG 

Colorado -56,252 241 -574 -555 46 56 0 

Idaho -504 1,320 -88 -284 0 -3 0 

Utah 650,722 653 -574 -1,233 49 -384 0 

Wyoming 345,625 3,629 -2,539 -1,555 -396 2,555 0 

Carbon Co, Wyoming -131,161 

3,629 -2,539 -1,555 11,417 2,555 

0 

Lincoln Co, Wyoming -93,086 6 

Sublette Co, Woming -24,304 696 

Sweetwater Co, Wyoming -48,612 11 

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CHAPTER 5—CUMULATIVE IMPACTS 

Table 5.5-3. Regional 2022-2008 emissions difference summary table (tpy), continued 

STATE Source Category 

Oil and Gas Area Onroad Offroad EGU NEGU Natural 

TOG 

Uinta Co, Wyoming -34,022 40 

Wyoming (rest) -2,716 2,510 

RFD 379,714 0 0 0 0 0 0 

CD-C Project 299,812 0 0 0 0 0 0 

PM10 

Colorado -25 2,048 -11 -60 182 -348 0 

Idaho 0 394 -3 -34 0 -468 0 

Utah 26 1,043 -14 -90 316 42 0 

Wyoming 8,406 24,037 -77 -369 -6,199 -1,419 0 

Carbon Co, Wyoming -10 240 

-77 

-74 3 415 0 

Lincoln Co, Wyoming -8 426 -43 -5,085 -908 0 

Sublette Co, Woming -130 928 -34 -3 -34 0 

Sweetwater Co, Wyoming -9 -1,239 -93 -1,107 -350 0 

Uinta Co, Wyoming -1 -78 -43 0 -53 0 

Wyoming (rest) -9 23,761 -81 -7 -489 0 

RFD 5,818 0 0 0 0 0 0 

CD-C Project 2,753 0 0 0 0 0 0 

PM2.5 

Colorado -24 -11 -13 -58 0 0 0 

Idaho 0 22 -3 -33 0 -376 0 

Utah 25 -64 -16 -86 90 24 0 

Wyoming 1,428 -311 -79 -328 -5,484 -902 0 

Carbon Co, Wyoming -10 -18 

-79 

-67 0 107 0 

Lincoln Co, Wyoming -8 11 -40 -5,720 -297 0 

Sublette Co, Woming -130 -2 -31 -3 -22 0 

Sweetwater Co, Wyoming -9 -180 -84 248 -528 0 

Uinta Co, Wyoming -1 -18 -40 0 -1 0 

Wyoming (rest) -9 -103 -68 -7 -162 0 

RFD 916 0 0 0 0 0 0 

CD-C Project 677 0 0 0 0 0 0 

5.5.2 Criteria Pollutants Impacts 

The results of the cumulative modeling showed that there would be no exceedances of the NAAQS, 

WAAQS, or CAAQS for ozone or any other criteria pollutant within the study area, except in the 

immediate vicinity of sources unrelated to the CD-C project. There would be predicted exceedances of the 

CO (8-hour), PM10/PM2.5 (24-hour), ozone, and SO2 (1-hour) standards within the study area; however, 

the CD-C project emissions would not make a significant contribution to these values. In addition, PSD 

increments would not be exceeded at any Class I or sensitive Class II area within the study area. 

Additional detail on the modeling results are provided in Section 4 of the AQTSD. 

Mid-Field Impacts 

CAMx-estimated criteria pollutant impacts from the CD-C project and regional sources, within and near 

the CD-C project area and these are shown in Table 5.5-4. As indicated in Table 5.5-4, the cumulative 

impacts resulting from project and regional sources would be below the WAAQS and NAAQS. 

5-16 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
 

CHAPTER 5—CUMULATIVE IMPACTS 

Table 5.5-4. CD-C project and regional sources: mid-field criteria pollutant modeling results 

Pollutant Averaging Time 

Modeled 

Concentration from 

All Sources 

(μg/m3) 

WAAQS 

(μg/m3

) 

NAAQS 

(μg/m3) 

CO 1-hour 

8-hour 

491.3 

357.0 

40,000 

10,000 

40,000 

10,000 

NO2 1-hour 

Annual 

81.41 

17.1 

n/a 

100 

188 

100 

O3 8-hour 142.4 147 147 

SO2 1-hour 

3-hour 

24-hour 

Annual 

30.82 

30.0 

11.3 

3.1 

n/a 

1,300 

260 

60 

196 

1,300 

365 

80 

PM10 24-hour 

Annual 

55.8 

7.5 

150 

50 

n/a 

50 

PM2.5 24-hour 

Annual 

18.7 

3.8 

n/a 

n/a 

35 

15 

1 NO2 1-hour concentration is 8th highest daily maximum 1-hour concentration. Value includes contribution from NO. 

2 SO2 1-hour concentration is 4th highest daily maximum 1-hour concentration. 

5.3.3 Visibility Impacts 

In the cumulative analysis, changes in light extinction from CD-C project sources combined with all 

cumulative emissions sources were calculated for each day at Class I and sensitive Class II areas within 

the study area (Map 4.5-1). The daily average differences in modeled concentrations between the 2022 

future and 2008 baseline years were calculated for each Class I/II area, and these concentration 

differences were used to estimate visibility impairment following FLAG 2010 guidance. The maximum 

and number of days greater than the 0.5 and 1.0 Δdv thresholds are disclosed. Two additional methods for 

evaluating cumulative visibility impacts were explored and a discussion of these methods and the results 

obtained from applying them are presented in Section 4.6.1 of the AQTSD. 

Cumulative visibility impacts at Class I and sensitive Class II areas estimated using the FLAG 2010 

method are shown in Table 5.5-5. The largest impacts would occur at Dinosaur National Monument, 

which would have the greatest number of days that exceed 0.5 Δdv and 1.0 Δdv thresholds. All Class I/II 

areas within the study area would have days in which the 2022–2008 concentration differences produce 

changes in extinction greater than 0.5 Δdv. The Mount Zirkel, Rawah, and Savage Run Wilderness areas 

would not have any days with impacts above 1.0 Δdv, but all other Class I/II areas would have days that 

exceed 1.0 Δdv. Using the 98th percentile value as a threshold, impacts at the Popo Agie Wilderness area 

are at the 0.5 Δdv threshold, and impacts at the Bridger, and Fitzpatrick Wilderness areas, the Wind River 

Roadless area, and Dinosaur National Monument would be above the 0.5 Δdv threshold, and the 1.0 dv 

threshold would be exceeded at only Dinosaur National Monument. 

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CHAPTER 5—CUMULATIVE IMPACTS 

Table 5.5-5. Cumulative visibility results 

Class I or Sensitive Class II Area Number of Days 

> 0.5 Δdv 

Number of 

Days > 1.0 Δdv 

Maximum 

Δdv 

98th Percentile 

Maximum Δdv 

Bridger Wilderness Area 9 1 1.30 0.52 

Fitzpatrick Wilderness Area 8 3 1.71 0.62 

Savage Run Wilderness Area 4 0 0.76 0.40 

Mount Zirkel Wilderness Area 5 0 0.77 0.43 

Rawah Wilderness Area 5 0 0.78 0.38 

Popo Agie Wilderness Area 7 3 1.73 0.50 

Wind River Roadless Area 9 3 1.55 0.55 

Dinosaur National Monument 30 12 2.11 1.29 

5.3.4 Atmospheric Deposition Impacts 

Modeled wet and dry fluxes of sulfur- and nitrogen-containing species due to emissions from the CD-C 

project and all other cumulative regional sources were processed to estimate total annual sulfur (S) and 

nitrogen (N) deposition values at each PSD Class I and sensitive PSD Class II area. Maximum predicted 

S and N deposition impacts were estimated for existing emissions sources within the CD-C project area 

taken together with the cumulative effects of all sources in the region. 

Table 5.5-6 shows maximum predicted total nitrogen and sulfur deposition impacts from all emission 

sources for the year 2022. Estimated cumulative nitrogen deposition impacts at all Class I and sensitive 

Class II areas within the study area would be above the critical load threshold of 1.5 kg/ha/yr. Estimated 

sulfur deposition impacts would be below the 3.0 kg/ha/yr threshold at all areas except for the Mount 

Zirkel Wilderness area and Dinosaur National Monument. Cumulative nitrogen deposition impacts can be 

addressed by a number of mitigation or development strategies designed to minimize NOx emissions from 

the project. These mitigation strategies are further described in Section 4.5.6, Unavoidable Adverse 

Impacts and Additional Mitigation Measures. Deposition impacts are summarized in detail in Section 

4.6.2 of the AQTSD. 

Table 5.5-6. Cumulative nitrogen and sulfur deposition impacts 

Class I or Sensitive Class II Area Nitrogen (kg/ha) Sulfur (kg/ha) 

Bridger Wilderness Area 2.76 2.88 

Fitzpatrick Wilderness Area 2.36 3.25 

Savage Run Wilderness Area 2.48 2.68 

Mount Zirkel Wilderness Area 4.17 5.43 

Rawah Wilderness Area 3.14 4.47 

Popo Agie Wilderness Area 2.56 3.66 

Wind River Roadless Area 2.26 3.60 

Dinosaur National Monument 4.51 6.02 

Table 5.5-7 shows the 2022–2008 change in maximum nitrogen and sulfur deposition at all Class I/II 

areas. The modeling results indicate that cumulative nitrogen and sulfur deposition impacts in 2022 would 

decrease in all Class I/II areas relative to year 2008. 

5-18 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
 

 

 

CHAPTER 5—CUMULATIVE IMPACTS 

Table 5.5-7. 2022-2008 Change in cumulative nitrogen and sulfur deposition 

Class I or Sensitive Class II Area Nitrogen Deposition Sulfur Deposition 

Deposition (kg/ha) % Change Deposition (kg/ha) % Change 

Bridger Wilderness Area -0.28 -9.0 -0.14 -9.1 

Fitzpatrick Wilderness Area -0.23 -6.6 -0.08 -4.7 

Savage Run Wilderness Area -0.28 -9.4 -0.11 -9.2 

Mount Zirkel Wilderness Area -0.51 -10.1 -0.27 -10.5 

Rawah Wilderness Area -0.40 -10.1 -0.19 -10.0 

Popo Agie Wilderness Area -0.29 -8.1 -0.15 -7.1 

Wind River Roadless Area -0.20 -5.2 -0.11 -5.1 

Dinosaur National Monument -0.36 -7.3 -0.25 -7.8 

Acidification at Sensitive Lakes 

Modeling results for cumulative sources indicated that there would be no ANC changes at any of the 12 

analyzed lakes that exceed the 10-percent threshold or the ΔANC<1 μeq/L threshold for the two 

extremely sensitive lakes. Lake ANC impacts are summarized in Section 4.6.3 of the AQTSD. 

5.3.5 Climate Change Impacts 

As discussed in sections 3.5 and 4.5 Air Quality, the current scientific consensus is that anthropogenic 

emissions of GHGs are causing the climate system to warm, and the impacts of this warming are likely to 

be larger in the 21st century than in the 20th century if emissiontrends continue unabated (IPCC, 2007). 

Forecasts of changes in the climate system under differing GHG emissions scenarios are made with 

global climate models. Forecasts of regional effects of global change derived from integrations of global 

models are available but are highly uncertain. In North America, predicted regional impacts of global 

warming include warming in western mountains, decreased snowpack, and increased frequency and 

intensity of heat waves (IPCC, 2007). 

The GHGs to be emitted by the Proposed Action and the action alternatives, and from other RFD projects 

in the study area, are CO2, CH4, and N2O, all of which have atmospheric lifetimes on the order of years 

(IPCC, 2007). Emissions of GHGs from any particular source become well-mixed throughout the global 

atmosphere. GHG emissions from all sources contribute to the global atmospheric burden of GHGs, and it 

is not possible to attribute a particular climate impact in any given region to GHG emissions from a 

particular source. Therefore, no modeled climate change impact predictions from Proposed Action or 

action alternative GHG emissions sources or cumulative GHG emissions sources in the vicinity of the 

project area are available. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 5-19 
CHAPTER 5—CUMULATIVE IMPACTS 

 BIOLOGICAL ENVIRONMENT 

5.6 VEGETATION AND RIPARIAN/WETLAND COMMUNITIES 

The CIAA for vegetation communities is the CD-C project area. Historic development in the project area 

accounts for 60,176 acres of initial disturbance and 17,663 acres of long-term disturbance. Added to this 

total, the Proposed Action and the action alternatives would disturb between 61,696 acres (Alternative A) 

and 36,499 acres (Alternative D) in the short term (Table 2.4-1). The long-term disturbance would range 

from 24,133 to 14,953 acres. Due to the long timeframe needed to recover shrub habitat, there would be 

an increase of acreage dominated by herbaceous vegetation versus that dominated by shrubs throughout 

the CD-C project area. 

Factors impacting vegetation besides removal include the indirect impact of dust accumulation on 

vegetation, resulting in reduced photosynthetic activity and growth and lower palatability for herbivores. 

Additionally, the increase in invasive species in the project area has already affected the native vegetation 

and would continue to do so. Vegetation is also impacted by other existing uses such as livestock grazing, 

wildlife foraging, and wild horse grazing. These uses will continue into the future and as available 

vegetation is removed, competition among these species (especially on critical winter range) could further 

impact the vigor of the vegetation in those areas. Soil loss and compaction in areas of construction can 

also contribute to the difficulty of reclamation. 

Wetlands and riparian communities are a very small component of the vegetation cover in the CD-C area. 

Protections are in place to protect these areas from physical impact, but those adjacent to gravel or dirt 

roads could be impacted by dust. 

Other actions within and near the CIAA could add to this impact. Roads within the project area are 

utilized to travel to adjacent projects such as the Atlantic Rim Natural Gas Field to the east and 

Desolation Flats to the west. Secondary roads may also be used to access the Luman Rim project adjacent 

to the northwest border of the project area. Additionally, three new transmission lines are proposed to 

cross the project area which would increase traffic during the planning and development stages. This 

additional use of the gravel and dirt roads within the project area would contribute additional dust and the 

vehicles could transport seeds of noxious plant species both into and out of the project area. 

5.7 INVASIVE, NON-NATIVE SPECIES 

The CIAA for invasive species is the CD-C project area and adjacent areas of development that could 

provide a seed source for invasive plants and also could provide sites for potential infestation by invasive 

species from the CD-C project area. 

Impacts to vegetation and range resources would occur on all lands in the project area under the Proposed 

Action and all action alternatives, as well as on private and state lands under the No Action Alternative, 

due to an increase in surface disturbance which could provide more suitable habitat for invasive weed 

infestations. 

Vehicles and equipment traveling from weed-infested areas, within and outside the project area, could 

facilitate the spread of invasive weeds into previously weed-free areas in addition to facilitating the 

spread of seeds of existing invasive populations. Surface-disturbing activities could increase the potential 

for infestation and spread of invasive plant species. Invasive weed species usually thrive on newly 

disturbed surfaces and out-compete more desirable native plant species. Creation of new sites for weed 

infestations may occur in proximity to roads where fugitive-dust deposition on roadside plants reduces 

their density due to reduced photosynthetic activity and reduced vigor, thus providing a suitable habitat 

for invasive plants to establish. 

5-20 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
CHAPTER 5—CUMULATIVE IMPACTS 

In addition to the CD-C project, several other natural gas projects are located adjacent to the project area 

and could provide potential seed sources for establishment of invasive species in the project area. They 

include Atlantic Rim on the east of the project area, Desolation Flats on the southwest, and Luman Rim 

on the northwest. Additionally, three transmission-line projects are proposed to cross the project area and 

vehicles/equipment associated with the planning and construction of those projects provide other potential 

seed sources and seed vectors. 

5.8 WILDLIFE 

The cumulative impact analysis areas (CIAAs) for wildlife resources differ with respect to species. This 

analysis examines the proportion of the wildlife habitat within respective CIAAs that may be disturbed 

from all past, present, and RFFAs. The combination of individual projects results in a large area 

potentially exposed to increased fragmentation, disturbance of wildlife and their habitats, disruption of 

migratory corridors, and the loss of refuge areas. Additional effects are expected on wildlife dispersal, the 

reduction of non-fragmented habitats, competition with livestock, and competition with other wildlife 

species. The generalized increase of human presence and associated disturbance across such a broad scale 

are a concern. Remaining ranges with increased competition for forage leading to reduced carrying 

capacity and juvenile survival can also be expected for some species. Mitigations, COAs, and other BMPs 

would reduce the impacts of these developments, but not eliminate them. Reduced populations and 

population viability can be expected in high-density development areas. 

Cumulative indirect effects from the Proposed Action or alternatives and RFFAs to all wildlife species in 

general would come from road/traffic impacts, including vehicle collisions, noise, and dust. As roads are 

developed within and adjacent to the project area, habitat is fragmented. Roads can serve as barriers to 

some animal movement. The displacement of species away from roadsides can be reasonably predicted. 

Roads also provide access to the public into areas that were previously undisturbed/undeveloped. Human 

encroachment in the form of casual backcountry recreation, hunting, and poaching could occur at higher 

rates resulting in effects such as disturbance during sensitive periods, displacement, or increased 

mortality. 

Insects, birds, and amphibians all avoid dust and noise from roads, which compounds impacts to adjacent 

habitats throughout the CIAA. Sagebrush-obligate species would be affected by the cumulative removal 

of habitat (reduction or fragmentation of patch size or vertical habitat structure) and the expanded road 

system throughout the area. 

For raptors, small mammals, and neotropical migratory birds, the impacts anticipated from the Proposed 

Action, alternatives, and RFFAs would be similar with the exception of Alternative A (100-Percent 

Vertical Drilling) which would disturb more acreage over the long term. The Proposed Action and the 

action alternatives provide a variety of mitigations and protections for various wildlife species. 

Alternative B, with enhanced mitigations and protections, would enhance habitat for prey and grassland 

species. Alternative D, with required directional drilling on federal mineral estate, would reduce surface 

disturbance, and associated shrub habitat removal, by about 23 percent when compared to the Proposed 

Action. Under all Alternatives, with the exception of Alternative E (No Action), sagebrush obligates 

would experience an overall reduction in suitable habitat for the life of the various projects within the 

CIAA. 

5.8.1 Big Game 

Disturbance during construction and production, such as human presence, dust, and noise may displace or 

preclude big game use during all seasons. Prohibiting construction, drilling, and other activities 

potentially disruptive to wildlife during sensitive time periods (e.g. winter) would minimize the 

probability of displacement during these critical times. The extent of displacement would be related to the 

duration, magnitude, and visual prominence of the activity, as well as the extent of construction and 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 5-21 
CHAPTER 5—CUMULATIVE IMPACTS 

operational noise levels above existing background levels. Displacement would result in local reductions 

in wildlife populations if adjacent, undisturbed habitats are at carrying capacity. In this situation animals 

are either forced into less-optimal habitats or they compete with other animals that already occupy 

unaffected habitats. Possible consequences of such displacement are lower survival, lower reproductive 

success, lower recruitment, and ultimately lower carrying capacity and reduced populations (WGFD 

2010). Refer to Section 4.8.3 for a more in-depth discussion of possible direct and indirect impacts of the 

CD-C project or other CIAA projects to big game. 

Construction, such as building well pads and roads, reduces forage available to big game. The 

significance of this forage reduction is greater in big game CWR, especially as development cumulatively 

and concurrently occurs outside the project area in adjacent oil and gas development areas. The 

application of seasonal restrictions intended to minimize CWR disturbance could serve to further 

concentrate big game in those refuge areas. These seasonal restrictions are not generally applied in state 

and fee energy development areas. In addition, new gas field-related roads provide unconstrained access 

to the general public which could result in increased human presence during sensitive periods such as 

winter. Recreational “antler hunting” has been identified by WGFD as an issue in CWR in some areas of 

the state. 

Big game populations are managed within Herd Units designated for each species and cumulative impacts 

are discussed in the context of these areas. Implementation of the proposed project would affect crucial 

winter/winter yearlong range for these big game species. Elk are not considered in this cumulative impact 

analysis as CWR for the species would not be impacted by the CD-C project. The specific locations of 

future disturbances within the CD-C project area and the other RFFAs (Section 5.0) that fall within the 

Herd Units and crucial seasonal habitats are unknown; therefore, the exact location of each seasonal big 

game range or migration route that may be affected by development activity is unknown. The cumulative 

portion of each CD-C big game CWR that could be affected by the combination of existing, proposed, 

and RFFA disturbances for pronghorn and mule deer is discussed below. Cumulative impacts to big game 

would include permanent, short-term, and long-term loss of habitat, as well as increased stress due to 

human/wildlife encounters, potential reductions in birth/survival rates, and possible alterations of 

migration routes. 

Pronghorn. The cumulative impact analysis area for pronghorn comprises the Herd Units impacted by 

the CD-C project (Map 5.8-1). Cumulative impacts to pronghorn migration routes are unknown at this 

time; however, the current fencing along WY 789 creates a barrier to pronghorn attempting to migrate 

across this highway. The WGFD has constructed highway underpasses along WY 789 in an effort to 

provide safe access during migration and reduce the frequency of vehicle collision; however, pronghorn 

do not appear to use these accommodations (WYDOT 2012, J. Gregson pers. com. January 2012). I-80 

constitutes a significant barrier to pronghorn seasonal movements. Dependent on the severity of the 

winter, there are miles of rangeland fence that also create migration barriers for pronghorn. 

It is assumed that most, if not all, of the Baggs herd transition range is located within the interface of the 

CD-C and Atlantic Rim project areas (BLM 2007) along WY 789. Approximately 76 percent of the 

Baggs Herd Unit crucial winter/yearlong range could be affected by long-term development in the 

following areas: 30 percent within the CD-C project area, 42.6 percent within the Atlantic Rim project 

area, and 3.4 percent within new transmission line corridors. Virtually all of the Baggs pronghorn crucial 

winter range lies within one or more oil and gas project boundary. 

Approximately 44.5 percent of the Bitter Creek Herd Unit CWR is located within the project area for the 

Proposed Action and other RFFAs including Hiawatha (22.7 percent), CD-C (10 percent), Desolation 

Flats (6.5 percent), and new transmission line corridors (3 percent), as well as other existing oil and gas 

development actions. The CD-C project and new transmission line corridors could affect approximately 

19 percent of the Red Desert Herd Unit CWR. It is anticipated that the CWR in the Red Desert Herd Unit 

would also be affected by scattered oil and gas development activities. 

5-22 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
CHAPTER 5—CUMULATIVE IMPACTS 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

Map 5.8-1. Cumulative impact analysis area, pronghorn 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 5-23 
CHAPTER 5—CUMULATIVE IMPACTS 

Mule deer. The cumulative impact analysis area for mule deer comprises the Herd Units impacted by the 

CD-C project (Map 5.8-2). Cumulative impacts upon mule deer migration routes within the Baggs Herd 

Unit are unknown; however, WGFD and the Wyoming Department of Transportation have constructed 

highway underpasses along WY 789 in an effort to provide safe access during migration and reduce the 

frequency of vehicle collision. Mule deer are successfully using these underpasses (WYDOT 2012, J. 

Gregson pers. com. January 2012). 

As with pronghorn, it is assumed that most, if not all, of this herd’s transition range is located within the 

interface of CD-C and Atlantic Rim project areas (BLM 2007) along WY 789. Approximately 6 percent 

of the Baggs Herd Unit crucial winter/year-long range could be affected by long-term development within 

the CD-C project area, another 26 percent falls within the Atlantic Rim project area, 7 percent would be 

affected by the Desolation Flats project, and approximately 4 percent is located within 0.5 mile of 

proposed new transmission-line corridors. Over 44 percent of the Baggs mule deer CWR may lie within 

one or more reasonably foreseeable oil and gas project or transmission line corridors. As discussed in 

Section 4.8.3.1, predictive maps suggest some habitats considered “high probability of use” areas prior to 

development would change to “low probability of use” areas as development progresses. These impacts 

would be increased as the CD-C, Atlantic Rim, and Desolation Flats projects are developed. 

Approximately 31 acres of mule deer CWR are identified in the Chain Lakes Herd Unit, none of which 

would be affected by the CD-C project or other RFFAs. None of the CWR in the Steamboat Herd Unit 

would be affected by the CD-C project; approximately 2 percent could be influenced by new transmission 

line corridors. 

Elk. The cumulative impact analysis area for elk comprises the Herd Units impacted by the CD-C project. 

No elk CWR or migrations routes have been identified in the CD-C project area. 

Overlapping big game crucial winter ranges are located at the interface of the CD-C project area and 

the Atlantic Rim project area along WY 789 (Map 3.8-7). As discussed above, this area is expected to see 

additional development and production activity resulting in additional stress and displacement of 

pronghorn and mule deer, as well as reduced winter forage as a result of increased surface disturbance. 

Impacts to these herds would be exacerbated by the current fair to poor condition of forage in crucial 

winter habitat designated areas (see Section 4.8.3.1). Over the long term, the impacts anticipated from the 

CD-C project and RFFAs would be similar for the various CD-C project area development alternatives 

with the exception of Alternative A (100-Percent Vertical Drilling) which would disturb more acres over 

the long term, and Alternative D which would reduce total surface disturbance, and associated shrub 

habitats, by approximately 23 percent, when compared to the Proposed Action. Alternative B (Enhanced 

Resource Protection) and Alternative C (Surface Disturbance Cap with High and Low Density 

Development Areas) would both provide protection to big game CWR areas over the life of the project. 

The ERP provides a variety of impact thresholds, each of which enhances the mitigation and protection 

for wildlife species and their respective critical seasonal ranges. BLM seasonal restrictions and those 

enhancement provided under Alternative B are not generally applied in state and fee energy development 

areas. 

An indirect impact of these CIAA actions includes unrestricted access by the general public using gas 

field-related roads which could result in increased human presence in CWR during sensitive periods. 

Recreational “antler hunting” has been identified by WGFD as an issue in CWR in some areas of the 

state. 

5-24 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
CHAPTER 5—CUMULATIVE IMPACTS 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

Map 5.8-2. Cumulative impact analysis area, mule deer 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 5-25 
CHAPTER 5—CUMULATIVE IMPACTS 

5.8.2 Raptors 

The CIAA for raptors includes the CD-C project area plus a 1-mile buffer (Map 5.8-3). This area covers 

approximately 1,226,825 acres, all of which would be considered raptor foraging habitat. Approximately 

939 nests are known to occur in the CIAA; 780 known nests (83 percent) are within the project area, 122 

nest sites are located in the CIAA of overlap between Atlantic Rim and CD-C project area, 14 would 

possibly be affected by transmission lines, and another 14 lie in the overlap area between Desolation Flats 

and the CD-C project area. Approximately 61 percent of the known nests are ferruginous hawk, 10 

percent are golden eagle, and 5 percent are red-tailed hawk; the remaining 25 percent are various species 

including burrowing owl, prairie falcon, American kestrel, and unknowns. Potentially positive cumulative 

impacts from the creation of additional nesting sites (i.e., artificial nesting structures including 

hydrocarbon stock tanks) are known from other conventional oil and gas projects in the vicinity of the 

CD-C project area. 

As with the Proposed Action and the various alternatives analyzed, the required buffers and restrictions 

on activity around active raptor nests and the fact that most of the prey utilize habitat that can be 

reclaimed in a timely fashion, the impacts on most raptor species in the CD-C project area and associated 

RFFA overlap areas is not expected to exceed the significance criteria. However, the BLM timing 

stipulations for protection of raptor nests is not applied on State and fee energy development actions. 

Refer to Section 5.9.3 for a discussion of CIAA on the ferruginous hawk. 

5.8.3 Fish 

Cumulative impacts to fish species would include the effects of the CD-C project and other developments 

upstream in Muddy Creek, the most notable of which is the Atlantic Rim Natural Gas Project. At this 

time there are no known additional proposals to analyze or assess. 

About 10 game-fish species and 20 non-game fish species may occur within or upstream/downstream 

from these two project areas. Of these, about 14 species, including six native species, are likely to be 

present within the project areas. Of the 14, four are BLM Sensitive Species and 10 are not. All of the 10 

species that are not BLM sensitive would be subject to the same types of impacts described in Section 

4.9.3.1. Sensitive Fish Species; however, they have a wide distribution within Wyoming (Baxter and 

Stone 1995). Consequently, the project area and other human activities within the Muddy Creek and 

Great Basin watersheds may have localized population impacts, but these impacts should not impact their 

status range-wide. 

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CHAPTER 5—CUMULATIVE IMPACTS 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

Map 5.8-3. Cumulative impact analysis area, raptors 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 5-27 
 

CHAPTER 5—CUMULATIVE IMPACTS 

5.9 SPECIAL STATUS PLANT, WILDLIFE, AND FISH SPECIES 

The CIAAs for wildlife resources differ with respect to species. The combination of the individual 

projects could result in a large area of increased fragmentation, disturbance of wildlife and their habitats, 

disruption of migratory corridors, and the loss of refuge areas. Additional effects could be wildlife 

dispersal, the reduction of non-fragmented habitats, competition with livestock, and inter-specific 

competition. The generalized increase in human presence and associated disturbance across such a broad 

scale are a concern. It can also be expected that competition for forage would increase in the remaining 

habitats leading to reduced carrying capacity and juvenile survival for some species; see Section 4.9.3 for 

a more detailed discussion of potential impacts to special status species. Mitigations, COAs, and other 

BMPs would reduce the impacts of these developments, but not eliminate them. Reduced populations and 

population viability for some species can be expected in high density development areas. However, the 

BLM mitigations, COAs, BMPs etc., are not generally applied on state and fee energy development 

actions. 

5.9.1 Threatened, Endangered, Proposed or Candidate Wildlife Species 

Threatened and Endangered Wildlife Species 

Black-footed ferret. The presence of black-footed ferret in the CD-C project area is very unlikely (see 

Section 3.9.1.1). The various CD-C alternatives would likely disturb colonies of white-tailed prairie-dogs, 

which are the black-footed ferret’s primary habitat and prey source in this area. Surveys for black-footed 

ferrets may be required before ground-disturbing activities within identified prairie-dog complexes 

located in the Continental Divide, Dad, and Desolation Flats non-block clearance areas for all RFFAs 

potentially affecting those areas (Map 5.9-1). Without pre-disturbance surveys, significant impacts could 

occur in the non-block cleared areas; for example, almost 95 percent of the Dad and 80 percent of the 

Desolation Flats non-block clearance areas could be affected by the CD-C project area and other RFFAs. 

However, of the white-tailed prairie dog complexes identified as potential black-footed ferret habitat 

(Map 5.9-1), it is anticipated that only Complex 1 would be impacted and only by the CD-C project. 

Complexes 2 and 3 are located to the west of CD-C and are not encroached upon by any of the other 

CIAA project boundaries. 

The remaining white-tailed prairie-dog colonies within the CD-C project are in the “Block clearance” 

area, where surveys for black-footed ferrets are no longer warranted. The CD-C project area and RFFAs 

are not expected to exceed the impact significance criteria for black-footed ferret populations. 

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CHAPTER 5—CUMULATIVE IMPACTS 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

Map 5.9-1. Cumulative impact analysis area, black-footed ferret 

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CHAPTER 5—CUMULATIVE IMPACTS 

Greater sage-grouse. Approximately 60 percent of the CD-C project area is comprised of sagebrush and 

other shrub species, which represents potential greater sage-grouse nesting habitat. Recovery of shrubs, in 

locations that have been disturbed by development, to pre-disturbance levels is not expected to occur 

during the life of the project. Therefore, even locations that are successfully reclaimed would represent a 

long-term loss of nesting habitat; however, these areas would be used as early brood-rearing and foraging 

habitats throughout the seral stages. 

Per IM WY-2012-019, an 11-mile analysis area buffer is required around the project boundary for largescale proposed actions (e.g. oil and gas full-field developments). This 11-mile buffer (Map 5.9-2) was 

used as the CIAA for greater sage-grouse breeding and nesting habitats potentially affected by the CD-C 

project and associated RFFAs, including the Luman Rim, Lost Creek, Desolation Flats, South Baggs, and 

Atlantic Rim projects. This area encompasses portions of the South Rawlins, Greater South Pass, 

Continental Divide, and Salt Wells Core Population Areas. Of these only the Greater South Pass and 

South Rawlins Core Population Areas would be directly affected by the CD-C project or RFFAs. 

One-hundred ninety-two (192) known leks are located within 11 miles of the CD-C project area; 105 are 

occupied, 13 are unoccupied, and 74 have undetermined status (see Map 3.9-2). Another 67 known sagegrouse leks are located within the CD-C project area, for a total of 259 leks within the CD-C project 

CIAA. One-hundred sixty-eight (168) of these leks are occupied. All 259 leks would potentially be 

affected by the CD-C project or RFFAs as indicated on Map 5.9-2. Sixty-three (63) would possibly be 

directly affected by the CD-C project, 44 by Atlantic Rim, 18 by transmission line corridors and another 7 

by various oil and gas projects. Other areas within the 11-mile buffer and associated Core Population 

Areas would be affected by scattered energy developments and anthropogenic features on the landscape. 

Greater sage-grouse inhabit the CD-C project area and surrounding area year-round and require a wide 

range of seasonal habitats. The area of highest sage-grouse lek concentration in the 11-mile CIAA falls to 

the south of I-80 and east of WY 789, along the interface of CD-C and Atlantic Rim (Map 3.9-2). 

Approximately 81 occupied leks are known to be located in this area of high-quality/high-potential 

nesting and brood-rearing habitat. This area also contains large expanses of high-quality/high-potential 

severe winter use habitat. 

Development activity may result in bird displacement and nest abandonment from direct and indirect 

impacts, such as long-term habitat fragmentation; loss of nesting or brood-rearing habitat; displacement or 

additional stress due to increased human activities including increased vehicle traffic, dust, excessive 

noise levels proximal to occupied leks; removal or modification of winter habitats; and increased 

predation due to an increased number of roosting sites available for raptors on power poles, tanks, and 

other man-made structures (see Section 4.9.3), especially in high-density development areas. 

Regardless of the alternative selected, application of the Core Population Area density and disturbance 

limitations and mitigations (IM WY-2012-019 and SWED 2011) is intended to reduce disturbance to the 

habitat and the species to the point that sage-grouse populations within Core Population Areas are not 

negatively impacted. These restrictions would apply on all surface ownerships. Alternative D (100­

Percent Directional Drilling) would reduce surface disturbance from road and well site locations by about 

23 percent compared to the Proposed Action. Alternative E (No Action) would limit CD-C development 

activities to private and state mineral estates, thereby limiting additional impacts sage-grouse habitat and 

populations within the CD-C project area. 

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CHAPTER 5—CUMULATIVE IMPACTS 

No warranty is made by the BLM for use of the data for purposes not intended by the BLM. 

Map 5.9-2. Cumulative impact analysis area, greater sage-grouse 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 5-31 
 

CHAPTER 5—CUMULATIVE IMPACTS 

In non-core areas, application of applicable IM WY-2012-019 and SGEO (Greater Sage-grouse Core 

Area Protection program) standards for avoidance of potential nesting and brood-rearing habitat as well as 

the Rawlins RMP (BLM 2008a) standard COAs, BMPs, Timing Limitations, and mitigation would 

reduce the potential impact to sage-grouse but impact to those populations would still be anticipated. 

Alternative A would have the greatest potential for impact to non-core sage-grouse populations. 

Alternative B would provide enhanced mitigations and protections for sage-grouse as well as other highvalue resources. Under Alternative C, the disturbance cap would place a limit on the amount of 

unreclaimed surface at any one time in a section of public land. Alternative D (required directional 

drilling on federal mineral estate) would reduce surface disturbance from road and well-site locations by 

about 23 percent compared to the Proposed Action. Restrictions applied for protection of sage-grouse 

habitat in non-core areas, found in IM WY-2012-019 and SGEO, would apply on state, fee, and federal 

lands. Alternative E (No Action) would limit CD-C development activities to individually permitted 

federal activities and private and state mineral estates, thereby limiting additional impacts to project area 

sage-grouse habitat and populations. 

5.9.2 Threatened and Endangered Fish Species 

Cumulative impacts to Threatened and Endangered fish species would include the effects of the CD-C 

project and other developments upstream in Muddy Creek, of which the most notable is the Atlantic Rim 

Natural Gas Project. At this time there are no known additional proposals to analyze or assess. 

Four federally endangered fish species may occur as downstream residents of the Colorado River system: 

Colorado pikeminnow (Ptychocheilus lucius), bonytail (Gila elegans), humpback chub (Gila cypha), 

and razorback sucker (Xyrauchen texanus) (USFWS 2003). Suitable habitat for these species does exist 

downstream of the CD-C and Atlantic Rim project areas in the Little Snake, Yampa, and Green Rivers. 

Because the Colorado pikeminnow is found in the Little Snake River, it could migrate into Muddy Creek, 

which makes Muddy Creek potential habitat for this species. Muddy Creek, however, is not suitable 

habitat for this species. Neither of the action alternatives for these projects is expected to affect this 

habitat, provided that mitigation measures for water resources and soils outlined in this document are 

implemented. Though they currently exist only downstream of the project area, water draining from the 

project area affects the downstream habitat for these species. Under the Proposed Action, the sources of 

potential risks to these fish species are water depletions, discharges of produced water, and spills of toxic 

materials. 

Water Depletions. Under the Recovery and Implementation Program for Endangered Fish Species in the 

Upper Colorado River Basin, “any water depletions from tributary waters within the Colorado River 

drainage are considered as jeopardizing the continued existence of these fish.” A small amount of water 

depletion may occur for the Atlantic Rim Natural Gas Project, and the Proposed Action may deplete an 

average of 510 acre-feet of water per year from aquifers in the Wasatch formation that may have contact 

with and contribute to the Little Snake River and its tributaries, including Muddy Creek. 

Discharges of Produced Water and Spills of Toxic Chemicals. Produced water from the CD-C project 

area will not be discharged to Muddy Creek within the Little Snake River drainage; therefore, producedwater discharges will not pose a potential risk to these species. The Atlantic Rim project, however, has 

produced-water discharges to Muddy Creek that may be altering the hydrology of the creek. 

Accidental releases (e.g., spills) of toxic chemicals also could occur. However, accidental releases of 

toxic chemicals should become highly diluted before they would reach any downstream waters where 

these species occur; consequently, the potential risks from such occurrences are negligible (BLM 2007). 

5.9.3 Threatened and Endangered Plant Species 

The CIAA for Threatened and Endangered Plants is the CD-C project area. As described in Section 4.9.3, 

direct impacts to the threatened Ute ladies’-tresses (Spiranthes diluvialis) are not anticipated to occur. The 

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application of the 500-foot buffer for riparian areas would provide protection for this species. If suitable 

habitat (i.e. riparian areas) were present, the proposal would be modified so impacts were avoided. The 

BLM stipulation for avoidance of riparian areas is not applied to state and fee energy development 

actions. 

5.9.4 Sensitive Wildlife Species 

Chapter 4 analyses determined that implementation of the Proposed Action or other analyzed alternatives 

is not expected to exceed the impact significance criteria for pygmy rabbit, swift fox, white-tailed prairie 

dog, Wyoming pocket gopher, bald eagle, burrowing owl, sagebrush obligate avian species, or mountain 

plover with the caveat that BLM mitigation measures be applied regardless of alternative selected. In 

addition, Alternative B provides enhanced protections for: greater sage-grouse leks, nesting/brood-rearing 

habitat, and winter concentration areas (Section 4.9.3) and ferruginous hawk nesting habitat. Alternative 

D reduces surface-disturbing activity by almost 23 percent compared to the Proposed Action. 

The caveat regarding application of BLM mitigation measures for special status species would apply to 

all RFFAs as well as the CD-C project but would not apply to privately-owned checkerboard lands or 

state or private mineral estate in the CIAA. While some disturbance of these species would likely occur 

on private lands, it is not expected that impact significance criteria would be exceeded. 

Ferruginous hawk. Concerns are identified (Section 4.9.3) regarding potential impacts to ferruginous 

hawk from disturbance to nesting/foraging habitats. The CIAA for raptors includes the CD-C project area 

plus a 1-mile buffer (see Map 5.8-3). This area covers approximately 1,226,825 acres, all of which would 

be considered raptor foraging habitat. Approximately 577 ferruginous hawk nests are known to occur in 

the buffered CD-C project area. Potentially positive cumulative impacts from the creation of additional 

nesting sites (i.e., artificial nesting structures including hydrocarbon stock tanks) are known from other 

conventional oil and gas projects in the vicinity of the CD-C project area. However, an undetermined 

number of active nest sites would not be protected by application of the BLM timing stipulation and 1­

mile buffer on state and fee lands/minerals, especially in the “checkerboard.” Overall, because of the 

required buffers and restrictions on activity around raptor nests and because of the fact that most of the 

prey utilize habitat that can be reclaimed in a timely fashion, the impact on ferruginous hawks in the 

project area and associated RFFA overlap areas is not expected to exceed the significance criteria. 

Sensitive Fish Species. Cumulative impacts to sensitive fish species would include the effects of the CDC project and other developments upstream in Muddy Creek, of which the most notable is the Atlantic 

Rim Natural Gas Project. At this time there are no known additional proposals to analyze or assess. 

Sensitive fish, described in Section 4.9, would be significantly impacted by both the CD-C and Atlantic 

Rim projects (Criteria 3 and 4). The types of impacts resulting from both projects would be similar and 

cumulative in their effects. The primary cause of impacts would be increases in suspended sediments and 

sedimentation. One difference in the Atlantic Rim project as compared to the CD-C project is that 

Atlantic Rim has produced-water discharges to Muddy Creek that may be altering the hydrology of the 

creek. 

Impoundments downstream of the CD-C project may be blocking sensitive fish movement into Muddy 

Creek, but are not attributable to the CD-C project. As detailed in Chapter 4, additional impoundments 

and alterations to natural flow characteristics (such as crossings) within Muddy Creek could have serious 

additional impacts to fish populations. Alteration of hydrology from roads, culverts, and other 

disturbances that result in re-channeling of overland flows into new channels or increasing the 

intensity/volume of flows within existing channels can affect sensitive fish. Blockage of fish migration 

within the CD-C project area as a result of channel crossings would seriously impact the viability of fish 

populations if it should occur. 

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CHAPTER 5—CUMULATIVE IMPACTS 

Alternative B, the Enhanced Resource Protection Alternative for the Muddy Creek Corridor/ Watershed 

described in Section 2.2.3.4 could significantly reduce project impacts to sensitive fish species, if they 

were applied to both BLM and private and state land within the CD-C project area. Without the 

application of these protections to private and state land, however, the benefits of these enhanced resource 

protections could be negated by increased drilling activities on private and state land. Consequently, 

alteration of fish habitat suitability from increases in suspended sediments and sedimentation could result 

in significant impacts to sensitive fish species. 

5.9.5 Sensitive Plant Species 

The CIAA for sensitive plants is the CD-C project area. As described in Section 4.9.3, direct impacts to 

sensitive plant species on federal land are unlikely to occur because the potential presence of these species 

would be determined by soils survey or rare-plant surveys prior to site development. Management 

practices identified on a case-by-case basis would be applied to surface-disturbing activities to maintain 

or enhance Special Status Plant Species and their habitats (BLM 2008b, p. 2-47). Indirect impacts include 

dust affecting plant health and reproduction and invasive species being introduced in the adjacent habitat 

and competing with the sensitive plants. 

Adjacent projects that could increase the dust and invasive species problem within the CD-C project area 

include Atlantic Rim on the east of the project area, Desolation Flats on the southwest, and Luman Rim 

on the northwest. Additionally, three transmission-line projects are proposed to cross the project area and 

vehicles/equipment associated with the planning and construction of those projects would provide other 

potential sources of dust and seed. The only sensitive plant that might be encountered during 

transmission-line construction is the Gibben’s beardtongue. The surveys mentioned above should ensure 

that these plants, if encountered, would be avoided. The protections applied to sensitive species plants 

relative to BLM actions are not applicable to state and fee energy development actions. 

5.10 WILD HORSES 

The CIAA for wild horses includes the Lost Creek and Adobe Creek Herd Management Areas (HMAs). 

Impacts to wild horses associated with the CD-C project would include disturbed land and associated loss 

of available forage along with dust affecting forage palatability. There is also the potential for 

horse/vehicle collisions. 

The Adobe Town HMA is generally located within the Desolation Flats Natural Gas Project area and 

impacts to the herd are more likely to happen in that area than in the CD-C project area. Two of the 

proposed transmission lines have potential routes through the Adobe Town HMA. During planning and 

construction, increased activity along their alignments would increase chances for collisions and 

generation of dust and remove small amounts of forage at the tower sites. 

The Lost Creek HMA is located in the northwestern portion of the CD-C project area. It continues north 

from the CD-C boundary. The Luman Rim field is located to the west of the HMA and effects from 

vehicles accessing that field through the CD-C are possible. The Lost Creek HMA may also receive 

impacts from traffic associated with the Lost Creek Uranium Project. 

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 HUMAN ENVIRONMENT 

5.11 VISUAL RESOURCES 

The CIAA for visual resources is the VRM Class III area within the CD-C project area. At roughly 1.1 

million acres, the project area is large enough to enclose virtually all the potential foreground to 

middleground views of VRM Class III. 

VRM Class III is the highest management classification within the project area. For the combination of 

landscape quality and viewer sensitivities prevalent within the project area, identifying visual impacts that 

might dominate a foreground to middleground view is critical to evaluating management actions for 

compliance with the VRM Class III standard. As described in Section 4.11.2, the RFO manages VRM 

Class III land for moderate change to visual resources by mitigating impacts through the use of BMPs as 

conditions of approval to APDs and right-of-way permits. 

Cumulative actions that could affect VRM Class III in the CD-C project area are oil and gas development 

and electrical transmission line systems and rights-of-way. Development on BLM land combined with the 

same or similar actions on state and private land would result in cumulative visual impacts. Cumulative 

impacts would be especially likely to occur in the checkerboard and other areas of mixed ownership 

because BLM does not have the jurisdiction to mitigate these actions. 

Cumulative impacts due to oil and gas development 

Cumulative impacts due to oil and gas development would occur within the CIAA solely because of the 

CD-C project alternatives. No major oil and gas developments listed in Table 5.0-1 overlap the CIAA. 

Consistent with the analysis in Chapter 4, the greatest potential for cumulative impacts to visual resources 

from oil and gas development in the CIAA would occur under Alternative A, which would allow the 

highest level of surface disturbance. 

Alternatives B through D would reduce the amount of surface disturbance due to oil and gas 

development. Alternative E, No Action, would generate no new surface disturbance. Alternative D would 

cause the least amount of surface disturbance among the action alternatives (as described in Section 

4.11.3.5) by requiring the Operators to drill multiple wells from a single pad; multiple-well pads would 

not be required under the Proposed Action or other alternatives. Under Alternative E, much of the project 

area now affected by oil and gas development could gradually return to a reclaimed condition as oil and 

gas facilities on BLM land gradually become obsolete over time; therefore, the cumulative effect of 

Alternative E to scenic quality could be neutral to positive over the long term. 

The actual visual contrast rating of wells, roads, and other facilities of the Proposed Action and action 

alternatives would be conducted after approval of the CD-C project, when development targets are 

identified and as the required site-specific APDs and right-of-way permits are evaluated. It is the sitespecific location and intensity of development that actually determines the level of contrast perceived 

from a given view of the foreground to middle distance from a sensitive observation point. Site-specific 

location and intensity of development also determine the amount and type of mitigation required to 

achieve the management objective required by VRM Class III. This means that there is likely to be 

uncertainty for sometime as to whether cumulative impacts to specific viewsheds within the CIAA can be 

managed to a VRM Class III standard for the long term. 

Even on federal land, the Operators’ desired intensity and specific location of development could prevail 

over attempts to mitigate to a VRM Class III objective. This could occur despite BLM’s mandate to 

implement measures to manage VRM Class III viewsheds. The BLM’s authority to manage visual 

impacts in particular cases could be precluded when valid existing lease rights protect Operator activities. 

This limitation could leave a residual of unmitigated impact. In addition, parts of the CD-C project that 

target private and non-federal lands in areas of mixed land ownership are beyond BLM jurisdiction and 

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CHAPTER 5—CUMULATIVE IMPACTS 

could develop without adequate mitigation, leading to indirect impacts to visual resources on adjacent 

federal land 

Developed areas where roads, well pads, tanks, and drill rigs dominate a view may accumulate within the 

project area to the detriment of existing rural landscapes that were previously intact. If this level of 

disturbance occurs and is viewable from sensitive observation points, the VRM Class III standard would 

be exceeded. 

Cumulative impacts due to transmission lines 

Two electrical transmission line projects listed in Table 5.0-1 would cross VRM Class III parts of the 

CD-C project area: the Energy Gateway South Transmission Line Project (Gateway South) and the 

TransWest Express 600kV Project (TransWest). A third reasonably foreseeable transmission line from 

Table 5.0-1, Energy Gateway West, would cross only VRM Class IV land. Class IV land accommodates 

transmission lines by allowing a high level of modification to the existing landscape. Gateway South and 

TransWest are extended corridors that potentially would enter into many views as they traverse the CD-C 

project area. The three reasonably foreseeable transmission line projects are illustrated in Figure 5.0-1. 

The Approved Rawlins RMP has provided for future utility development by designating the routes of 

existing transportation and utility lines as corridors that would be suitable for new transportation and 

utility ROW systems (ROD Map 2-2). The RMP also recommends the exclusion from the designated 

corridors of incompatible uses, among which are range and wildlife habitat improvements and any 

facilities “that would attract public use” (ROD p. 2-17). As they are shown on Figure 5.0-1, the 

preliminary alternatives for the proposed Gateway South and TransWest fall within designated corridors 

identified by the Rawlins RMP (ROD Map 2-2). 

Although generally provided for by the Rawlins RMP, specific proposals for the Gateway South and 

TransWest projects would require site-specific environmental analysis and compliance with established 

permitting processes. Site-specific mitigation measures that could be applied during permitting to reduce 

the impact of transmission lines to a viewshed or to a specific observation point within the CD-C project 

area include properly siting latticed or appropriately colored towers against existing backgrounds or using 

topographical features to reduce visibility. 

While effective when available, site-specific mitigation treatments are in fact limited in their utility for 

transmission lines because of what is typically the sparse, low-lying vegetation and flatness of the terrain 

in the CD-C project area. Therefore, the development of the Gateway South and TransWest projects 

would likely introduce strong vertical elements of an industrial character (tower structures) which would 

clash with the strong horizontal, natural elements (plains, rims, low vegetation and wide horizons) of 

existing settings within the CD-C project area. 

The impact of the Gateway South and TransWest projects would likely be greatest where the utility ROW 

crosses or parallels travel routes. As shown on Figure 5.0-1, the southern extent of the western-most 

route alternative of the two transmission lines would cross interior BLM roads and the corridors of two 

historic trails, the Overland Trail and the Cherokee Trail. At those crossings, the transmission lines would 

adversely affect the viewshed of the roads and historic trails. Although the historic trail corridors are 

designated as “avoidance areas” for linear utility systems by the Rawlins RMP (Map 2-33b), a crossing of 

these corridors by a long-distance, north-south transmission line corridor is not explicitly excluded and 

may be impossible to avoid. 

In addition, the southern extent of the easternmost route alternative of the Gateway South project would 

co-locate with the WY 789 corridor. The WY 789 corridor includes, at its south end within the CD-C 

project area, two topographical features known as Flat Top Mountain and The Bluffs. Although they are 

mostly of local interest to residents of Carbon and Sweetwater counties, these prominent features 

contribute to settings of moderate scenic quality, which is the highest level of scenic quality found within 

the CD-C project area (BLM 2011a). As prominent features, Flat Top Mountain and The Bluffs are focal 

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points of foreground to middleground views that present themselves to travelers on WY 789 between 

Rawlins and Baggs, Wyoming. 

The typical adverse impacts caused by a transmission line project are visual clutter in the foreground to 

middleground of a view and the visibility of the tall towers, which are 140 to 190 feet high for highvoltage lines of this type. From many perspectives, tower structures would rise above the CD-C project 

area’s horizontal landforms and would likely appear prominently above the project area’s wide skylines, 

perhaps competing with prominent natural features. Since high-voltage transmission lines are industrial in 

character, introducing such facilities would alter the scenic quality of existing VRM Class III viewsheds 

that would be affected by the Gateway South or TransWest projects within the CD-C project area. 

Cumulative impacts conclusion 

The combination of CD-C project oil and gas development and the development of the Gateway South 

and TransWest transmission line right-of-way systems in the area south of I-80 and west of WY 789 

could combine to create a high cumulative impact in some viewsheds in the VRM Class III parts of the 

CD-C project area. In addition, development of oil and gas facilities throughout the CD-C project area 

may expose existing VRM Class III areas to under-mitigated, site-specific visual impacts. These could 

accumulate within a given viewshed because of minerals lease terms that limit the BLM’s ability to 

mitigate visual impacts or because of the BLM’s lack of jurisdiction over visual resources management in 

mixed ownership areas. 

Visual impacts from these two kinds of planned or reasonably foreseeable development may add up to a 

high enough level of incompatible contrast with existing settings to be non-compliant with VRM Class 

III. If this occurs repeatedly in a number of VRM Class III areas of the CIAA, BLM may find it necessary 

to reconsider its resource allocation decisions through an RMP amendment process. This could lead in the 

future to an amendment of the RMP and a new set of resource allocations that would expressly lower 

VRM management classifications as needed to reflect the cumulative impact of development on the 

condition of the visual resources of the CIAA. 

5.12 RECREATION 

The CIAA for recreation is the Western Extensive Recreation Management Area (ERMA) of the RFO. 

The CIAA/ERMA covers all public land in the RFO west of Rawlins. 

The recreation resources of the CIAA are those of the CD-C project area plus areas beyond the project 

area that include more of the same Hunt Areas, big game Herd Units, wild-horse management areas, 

contiguous blocks of public lands, and interconnected public roads. These combined resources support the 

recreation values of concern for the cumulative impacts analysis, namely big game hunting and dispersed, 

non-consumptive recreational uses that center on wild horses, other wildlife, and the character of the 

landscape. 

Projects potentially affecting recreation in the CIAA are the CD-C project and other projects identified in 

Table 5.0-1. Other existing and reasonably foreseeable future projects are the Atlantic Rim Natural Gas 

Field Development, the Desolation Flats Natural Gas Development, the Luman Rim natural gas project 

and the Sierra Madre part of the Chokecherry and Sierra Madre Wind Energy Project. 

Cumulative impact to hunting, which is the main recreation activity in the CIAA, would occur as surface 

disturbance from development of the CD-C and other projects accumulates. Cumulative impact to hunting 

recreation begins with displacement of big game species within Hunt Areas because of disturbance to 

critical habitat and development activity within those habitats at key times of year. Cumulative impacts to 

hunting recreation also may include impacts to big game populations at the herd level of the primary big 

game targets in the CD-C project area, pronghorn and mule deer, because of long-term disturbance to 

sagebrush habitat. 

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When big game species leave a Hunt Area, hunters soon leave as well, because hunting success declines. 

If Herd Units are affected, the animals available for harvest and therefore the supply of hunting 

recreation, as reflected in the number of licenses issued, may decline. The potential for cumulative effects 

to Hunt Area displacement and potentially reduced availability from the herd is perhaps highest for 

pronghorn pronghorn hunting. As indicated by Table 3.8-1, estimated populations in the largest 

pronghorn Herd Units of the CIAA (Red Desert Herd Unit north of I-80 and Bitter Creek Herd Unit south 

of I-80) had a slightly decreasing population trend from 2001 to 2009 and an estimated population lower 

than the objective in 2009. Mule deer also may be affected by cumulative, long-term disturbance of 

habitat. 

There are also indirect impacts associated with hunting in the CIAA that may arise as development 

disturbance and activity accumulate. One is the potential for financial impact to big game outfitters whose 

commercial success depends on access to, and hunter success in, the CIAA. Another is potentially lower 

hunter safety because of higher accident risk as hunter density rises where displaced game has 

concentrated. Finally, some hunters wishing to avoid industrial facilities locations for safety and aesthetic 

reasons may find it more difficult to do so as development density rises in the CIAA; this would raise the 

likelihood of a lower-quality experience for some recreational hunters. 

Relatively undisturbed scenery is an integral part of the recreation experience for activities such as 

wildlife viewing. Accumulating development would decrease the availability of this type of recreational 

setting throughout the CIAA, so recreationists seeking natural-appearing landscapes would have to travel 

elsewhere and perhaps for greater distances as the CD-C and other projects are fully developed over time 

and before landscapes are fully reclaimed. 

The re-establishment of mature vegetation after final reclamation would take as much as 30 years in some 

parts of the CIAA. Localized areas may not achieve successful revegetation for much longer. With project 

lives of 45 to 55 years underway or reasonably foreseeable, the CIAA is not likely to be fully reclaimed 

for habitat or appearance for 70 to 80 years from its initial status. Long-term cumulative impacts in the 

CIAA would be likely to affect from two to four generations of hunters, wildlife viewers, and dispersed 

recreational users that value solitude in a natural-appearing landscape. 

The greatest cumulative impacts to recreation would occur under Alternative A because of increased 

surface disturbance and less protection to visual resources, which contribute to the recreation setting. 

Cumulative impacts to recreation would be less under all other action alternatives within the CD-C 

project area, which implies lesser impact to the recreation resources of the CIAA as a whole. 

Under Alternative E, No Action, the recreation resources of the CD-C project area, which in turn is a 

large part of the CIAA for recreation as a whole, could gradually improve as new oil and gas development 

is avoided and as existing oil and gas facilities gradually become obsolete over time and are reclaimed. 

Under Alternative E, No Action, the recreation resources of the CD-C project area, which in turn is a 

large part of the CIAA for recreation as a whole, could gradually improve as new oil and gas development 

is avoided and as existing oil and gas facilities gradually become obsolete over time and are reclaimed. 

5.13 LANDS WITH WILDERNESS CHARACTERISTICS 

No Lands with Wilderness Characteristics have been identified within the CD-C project area. 

5.14 CULTURAL AND HISTORICAL RESOURCES 

The CIAA for cultural and historical resources is the CD-C project area. Archaeological sites generally 

are located in discrete areas and effects on these sites are a consequence of implementing surfacedisturbing activities associated with a development proposal. Impacts from past and present actions within 

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the project area could occur as a result of the following mineral development projects which overlap the 

CD-C project area: Continental Divide, Continental Divide/Wamsutter II, Creston/Blue Gap, and Patrick 

Draw. In addition to the Proposed Action, impacts from reasonably foreseeable future actions (Table 5.0-

1) include three transmission lines: the TransWest Express, Gateway West, and Gateway South. The 

TransWest Express is proposed to run from Sinclair, Wyoming to southern Nevada. The proposed route 

would begin just south of I-80 and east of Rawlins, heading west-southwest into the project area, and 

turning south in Sweetwater County toward the Wyoming/Colorado border. In all, the proposed route 

would traverse approximately 45–50 miles within the project area. The Gateway West transmission line 

from Glenrock, WY to Idaho would bisect the project area from east to west, running to the south of and 

roughly paralleling I-80 until approximately 10 miles from the western boundary, where it would turn 

northwest across I-80, and then west toward Rock Springs. Approximately 72 miles of the route would lie 

within the project area. The Gateway South transmission lines would also originate in Glenrock, 

following the same route as Gateway West into the project area, and then splitting into multiple routes 

running south toward Nevada (Map 5.0-1). In all, approximately 140 miles of routes would cross the 

southern portion of the project area. Assessment of impacts from these transmission lines would be 

speculative at this time since the final routes have not been approved. 

Given the average site density of .04 cultural sites per acre, approximately 1,888 sites could be located 

within accumulated disturbance areas for the Proposed Action compared to 2,467 for Alternative A; 1,821 

sites for Alternative B; 1,718 sites for Alternative C; 1,458 sites for Alternative D; and no sites for 

Alternative E, No Action. It should be noted that sites are not evenly dispersed throughout the study area, 

but are typically found along the major drainages and lower benches of escarpments that dominate the 

terrain in the project area. 

In addition, segments of the Cherokee and Overland Trails, the Lincoln Highway/Union Pacific Grade, 

and the historic Rawlins-Baggs Road traverse the project area. These segments, including those that 

contribute to overall eligibility for listing on the NRHP, are summarized in Table 5.14-1. 

Table 5.14-1. Historic trails and roads in the CD-C project area 

Trail/Road Total Miles, 

All Segments 

Total Miles, NRHPContributing Segments 

Overland Trail 22.49 14.08 

Cherokee Trail 13.32 4.49 

Lincoln Highway/Union Pacific Railroad Grade 45.24 16.24 

Rawlins to Baggs Wagon Road 15.18 0.00 

Source: D. Johnson, Western Archaeological Services, personal communication; 2011. 

As directed by law, cultural resources inventories and consultations would be conducted for any projects 

involving federal lands, and adverse effects to NRHP-eligible sites would be avoided or mitigated as 

appropriate. All activities associated with the Proposed Action would be in accordance with federal laws 

and agency guidelines. Impacts to any previously unknown NRHP-eligible sites that may be discovered 

during construction activities would be mitigated in accordance with this EIS. Although sites located 

within disturbance areas are avoided or mitigated, sites located outside of and adjacent to disturbance 

areas are vulnerable to indirect impacts such as vandalism, illegal collection, dust, and erosion. It is 

anticipated that there would be a cumulative increase in vandalism, illegal collection, and dust due to the 

increase in roads throughout the entire natural gas field, and increased erosion at sites located in the 

vicinity of well pads and associated pipelines where vegetation cover has been reduced or eliminated. 

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CHAPTER 5—CUMULATIVE IMPACTS 

5.15 SOCIOECONOMICS 

The CIAA for socioeconomic conditions includes Carbon and Sweetwater Counties. Given Rock Springs’ 

position as a regional service center for the natural gas industry in southwest Wyoming, the indirect 

effects of past, ongoing, and reasonably foreseeable future effects of regional natural gas development are 

also considered. 

Within the project area, 224 new wells were drilled during 2010 and an estimated 3,738 wells were in 

production at the end of 2010. Production activities, maintenance and workover expenditures, 

employment, and tax revenue generation associated with these wells will be ongoing, regardless of which 

alternative is selected by the BLM. Because much of the infrastructure to support this level of drilling and 

production is in place, ongoing production activities, expenditures, and employment associated with wells 

currently in production are considered part of both the baseline and cumulative effects analyses. 

Past and current natural gas drilling and production in the project area and elsewhere in the CIAA have 

resulted in the development of substantial infrastructure capable of supporting future development and 

production. In some cases this infrastructure has excess capacity relative to the current (mid-2011) levels 

of development. Examples of infrastructure put in place to support past and ongoing development include 

the natural gas operator and service company operations yards in Rock Springs, Wamsutter, Rawlins and 

Baggs, described in Section 3.15.1.1, as well as pipelines, service roads, and other ancillary facilities. 

Past and ongoing activities have also resulted in human resource development, such as a cadre of 

employees in natural gas drilling, production, and support companies. Finally, natural-resource and other 

industrial development has supported construction and operation of substantial commercial and public 

infrastructure in communities in the CIAA. This industrial, human, commercial, and public infrastructure 

is capable of supporting a certain level of ongoing and future natural resource and industrial development 

activity and serves as a base for expansion of capacities to support higher levels of development. 

A number of the reasonably foreseeable projects identified in Table 5.0-1 require regulatory approval to 

proceed. If approved, the wind energy, transmission line, and other projects could contribute to 

cumulative socioeconomic effects in specific areas of the CIAA. The potential for adverse cumulative 

effects such as labor force competition, housing shortages, and strained community infrastructure and 

services would occur primarily in the event of concurrent construction of these projects. The potential 

beneficial cumulative effects, including increases in tax revenues, would be longer-term. 

In contrast, the reasonably foreseeable natural gas projects, both currently approved and as yet 

unapproved, would contribute to cumulative socioeconomic effects over longer time periods and would 

affect socioeconomic conditions in a broader portion of the CIAA. 

Although each of the natural gas projects identified in Table 5.0-1 has or will have an assumed pace of 

drilling and development identified in the relevant NEPA document, as noted in Section 4.15.2, the actual 

pace of natural gas development in southwest Wyoming is variable and unpredictable because 

development depends on a variety of factors including energy demand, pricing, regulatory approvals, rig 

and manpower availability, transmission pipeline capacity, weather, and the investment and development 

strategies of individual energy companies. Consequently, the potential for cumulative socioeconomic 

effects would be greater during extended periods of natural gas demand. 

In the eastern portion of the CIAA, identified cumulative projects by 2020 include construction of the 

proposed Chokecherry and Sierra Madre (CCSM) Wind Energy Project, the Gateway West, Gateway 

South and TransWest Express transmission line projects, the Lost Creek In Situ Uranium Project, and the 

Medicine Bow Fuel & Power Coal-to-Liquids (CTL) Project. 

The proposed CCSM Wind Project would primarily affect the Rawlins portion of the socioeconomic 

CIAA, although some construction workers might also seek housing in Rock Springs and the Wamsutter 

and Baggs areas. Due to timing stipulations related to wildlife, active construction would likely occur 

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during a six-month period of three or four consecutive years, with 800 to 1,200 construction workers 

during the peak periods. Consequently, the potential for adverse temporary and short-term cumulative 

socioeconomic effects during construction would be high. Once construction is complete, socioeconomic 

effects would be largely beneficial. 

Construction of the TransWest Express, Gateway West and Gateway South transmission line projects 

could each affect one or more communities in the region, depending on routing, as the construction 

workforce moves through the area over one or two construction seasons. The effects would again be 

associated with demand for housing, community services, and fiscal effects related to project activity and 

the construction workforces. Operating work-force requirements of the wind energy and transmission 

lines are substantially smaller than the construction workforce needs. 

The Lost Creek In Situ Uranium Project would affect Bairoil and Rawlins during construction and 

operation. 

The Medicine Bow Fuel & Power CTL Project, a combination mining and industrial project, could create 

cumulative socioeconomic effects in Rawlins and other communities in Carbon and Albany Counties 

located outside the CIAA. This large project poses a potential for cumulative socioeconomic effects in 

Rawlins during the multi-year construction phase and initial staffing period for project operation. Once 

full-scale operations begin and housing and public infrastructure and services are in place to serve 

demand, the socioeconomic effects would be largely beneficial. 

The Bridger Mine expansion and proposed Sweeney Ranch, White Mountain, and Bridger Butte wind 

energy projects would primarily affect western Sweetwater County and the communities of Rock Springs 

and Green River. In the case of the Bridger Butte project, Uinta County and its communities could also be 

affected. The expansion of the Bridger Mine is ongoing and most socioeconomic effects of the project 

were considered in the baseline. Adverse socioeconomic effects of the wind energy projects would occur 

primarily during construction, with beneficial effects occurring as tax revenues began to flow to local and 

state governments. 

The final construction schedules for the proposed wind energy, transmission line, mining and other 

projects listed in Table 5.0-1 will not be known until they receive the required authorizations, approvals, 

and financing. It is also not possible to predict with accuracy the level of natural gas drilling that will 

occur in southwest Wyoming during the construction period for these projects. 

If construction for all or some of these projects were to overlap concurrently with an increase in natural 

gas drilling levels to 2007–2008 levels, another “boom” could ensue in the CIAA. In that case, 

cumulative impacts on area socioeconomic conditions would include short-term and long-term positive 

effects on local economic conditions, increased employment opportunities and increased local and state 

government tax royalties. 

Adverse effects would include demand for temporary and long-term housing resources that substantially 

exceed local supplies, demand for local government services that exceed some service capacities, and 

changes in local social conditions that could include social disruption in some communities. Increased 

employment opportunities in relatively high-paying construction and energy-development jobs would 

result in competition for workers to the detriment of existing businesses and government agencies that 

could lose existing employees and experience difficulty recruiting new employees. On the other hand, 

workers would benefit from the increased wages that would result from this competition, while 

simultaneously potentially facing higher costs of living. 

Shortfalls in temporary housing availability could be mitigated by development of temporary housing 

facilities. Medicine Bow Fuel & Power has proposed such facilities to accommodate construction workers 

on its CTL Project and the Power Company of Wyoming has indicated it would consider providing such 

facilities for CCSM. It is also becoming increasingly common for natural gas Operators and drilling 

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CHAPTER 5—CUMULATIVE IMPACTS 

companies to develop temporary housing; three such facilities, several rig camps, and the placement of 

dormitory units in local mobile-home parks were operational near the project area in 2007–2008. 

The pace of residential construction in most communities in the CIAA would need to increase 

substantially to accommodate cumulative demand for longer-term housing units, were several of the 

projects listed in Table 5.0-1 to overlap with an increase in natural gas development activities. 

Demands on housing and local government services associated with some of the wind energy and 

transmission line projects and natural gas development would be seasonal, presenting staffing challenges 

for counties and communities. Excess capacity exists in many public-utility infrastructure systems (e.g., 

water and wastewater systems) in the communities that would likely host the bulk of the construction and 

natural gas development workforce. Recent experience in the CIAA has been that relatively few families 

and school-age children have accompanied construction and natural gas workers to the area; 

consequently, local school districts could likely accommodate cumulative enrollment with existing 

facilities in the near term. In the longer term some schools may need to add or expand facilities and the 

lead-time to secure approval and funding from the Wyoming School Facilities Commission and plan and 

construct school facilities could mean that certain facilities would experience crowding until new 

facilities are available. 

Community services such as law enforcement, emergency response, social services, and road and bridge 

departments, which in some cases experienced reductions in funding levels, service provision, and staff 

cutbacks in recent years, would initially face constraints in responding to increased demand. For most 

projects, local receipts of sales and use tax revenues lag the increases in demand. In other cases, a 

jurisdictional mismatch could occur between jurisdictions benefitting from tax revenue accrual and those 

facing the demands. This lack of revenue, coupled with competition for workers and the difficulty in 

staffing for seasonal demand, would present substantial challenges for local governments in the early 

years of a boom. 

When ad valorem and production-related revenues—and for wind energy projects, energy production tax 

revenues—begin to flow from the cumulative projects, counties and special districts (and in some 

instances, school districts) will benefit from substantially increased revenues. However, municipalities 

will not benefit directly from these revenues. 

Cumulative development in the CIAA also holds potential to affect local attitudes, opinions, and lifestyles 

and these effects are likely to be mixed. Development of the wind energy, transmission line, mining, and 

other projects listed in Table 5.0-1, coupled with a moderate increase in natural gas development, would 

result in economic growth and increased employment opportunities in relatively high-paying jobs. These 

changes would create the prospect for improved financial status of many residents, which would 

correspondingly increase support for cumulative development activities, particularly among those 

segments of the community that would benefit directly or indirectly from the increased economic activity. 

On the other hand, dissatisfaction may occur among those residents whose economic activities and/or 

recreation activities rely on use of the same geographical areas as the Proposed Action and projects listed 

in Table 5.0-1, including ranchers, grazing operators, outfitters, hunters, and other recreationists. 

Moreover, if area residents perceive that wildlife habitat, scenic vistas, and other resources are being 

degraded by development, levels of dissatisfaction could become greater and more widespread. 

Given the cyclical nature of natural gas development and the potential for other energy development to 

occur, it is difficult to predict development and associated population levels with any certainty. Following 

population gains in response to cumulative construction activities, population in the CIAA would decline 

as construction is completed, perhaps dramatically in the event of multiple concurrent construction 

schedules. Exceptions to this pattern would include the mining projects and the Medicine Bow Fuel & 

Power CTL project, which have relatively large operating workforce requirements. If employment and 

population were to fall dramatically, businesses that expanded or opened to accommodate the temporary 

population influx would need to transition to accommodate the decreased demand. Some business 

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closures would be likely. Effects on area housing conditions could range from moderate to severe, 

depending on whether the construction and natural gas development demands were accommodated in 

temporary housing or if housing to accommodate the temporary workforce was developed with a postboom use in mind. In those cases, communities in the CIAA could reduce the amount of unoccupied 

temporary housing after construction is completed or if a slowdown in natural gas development were to 

occur. Similarly, the fact that most community infrastructure including water and sewer systems is 

already in place should help communities avoid substantial debt that would be difficult to service when 

population levels decrease. 

5.16 TRANSPORTATION 

The CIAA for transportation includes western Carbon County, eastern Sweetwater County, and the 

highway transportation network providing access to and within the project area. Cumulative effects on 

transportation would include changes in traffic volumes. These changes, when combined with traffic 

associated with the CD-C project, would affect overall travel conditions on the CIAA transportation 

network. Past, ongoing, and reasonably foreseeable activities expected to produce incremental and 

cumulative impacts within the CIAA are summarized in Table 5.0-1. 

Historic and ongoing traffic within the project area is associated primarily with natural gas drilling and 

production, grazing, and outdoor recreation. Within the project area, 224 new wells were drilled during 

2010 and an estimated 3,738 wells were in production at the end of 2010. Production-related traffic 

associated with these wells will continue for their remaining productive life and during abandonment and 

reclamation, regardless of which alternative is selected by the BLM. Using the trip-generation factors 

developed for this assessment, an estimated 726 AADT would be associated with drilling under the 

Proposed Action in the peak year and an estimated 798 AADT associated with production activities in the 

peak year. 

Within the project area, the reasonably foreseeable actions that could result in cumulative transportation 

impacts would be the previously authorized Desolation Flats and Luman Rim natural gas projects. 

Two county roads serving the project area also provide access to the Desolation Flats project area 

(DFPA): SCR 23/CCR 701 (Wamsutter–Dad Road) and CCR 700. Although these two roads have served 

development in both the project area and the DFPA for years, incremental increases in traffic on these 

roads could occur if natural gas demand and prices support an acceleration of drilling and fielddevelopment activities. 

Cumulative effects on county roads associated with the Luman Rim project are not anticipated. Primary 

access to the Luman Rim project area (LRPA) from I-80 is via SCR 21, which is outside the project area. 

It is possible to access the LRPA via two roads that traverse the CD-C project area; SCR 67 travels north 

from I-80 and intersects with SCR 20, which then exits the project area to the west and intersects with 

SCR 21 south of the LRPA. However, the longer travel distance from I-80 associated with this route 

discourages its use to access the LRPA for all but contractors and vendors who may be traveling to/from 

the LRPA from other job worksites within the CD-C project area. 

All of the projects listed in Table 5.0-1 could generate traffic increases on I-80, particularly during 

construction, although some of the affected sections of I-80 would be outside of the CIAA. Under an 

accelerated drilling scenario, periods of traffic impedance and congestion could be anticipated, and some 

increases in the number of accidents could be anticipated. Cumulative traffic effects could also increase 

road maintenance requirements for WYDOT and for both county road and bridge departments. 

The highest volume of incremental traffic on I-80 would likely be in conjunction with the CCSM Wind 

Energy project, proposed for development south of Rawlins. Materials, equipment and supplies deliveries 

for the CCSM project are anticipated to arrive by rail and be offloaded at an intermodal facility located 

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CHAPTER 5—CUMULATIVE IMPACTS 

either southeast of Sinclair or on the south side of I-80 west of Sinclair, which would result in relatively 

little cumulative truck traffic on I-80. However, daily commuting by workers and others, including trips 

by contractors, would result in incremental traffic on I-80. One option under consideration by the Power 

Company of Wyoming includes housing construction workers in Rock Springs and Laramie. Workers 

commuting from/to these communities to the CCSM project area would contribute to cumulative traffic 

effects on I-80 between Rock Springs and Rawlins or east of Rawlins for six to eight months during each 

of the anticipated four-year construction periods. These effects would be minimal given the substantial 

baseline volumes of traffic on I-80 in these locations. 

The Medicine Bow Fuel & Power CTL Project and the Sweeney Ranch, White Mountain, and Bridger 

Butte wind energy projects are all located some distance from the project area. The TransWest Express, 

Gateway West and Gateway South transmission line corridors projects pass through the project area, and 

some substations and ancillary facilities may also be located within the project area. Construction 

equipment, supplies, and materials for these projects could be transported by rail or, for the CTL project 

and some segments of the transmission projects, via US 30 from Laramie. Transport of materials, 

equipment, and supplies to these projects would also occur on I-80 and, when considered in conjunction 

with the forecast traffic for CD-C, would generate cumulative traffic increases on the highway. Large 

increases would occur primarily during construction of these projects and would therefore be temporary 

and short-term in nature. 

Construction and operations of the Lost Creek In-Situ Uranium Project could contribute to cumulative 

traffic impacts along I-80, although materials coming from the north—e.g., from Casper—would likely 

access the Lost Creek project via US 287. Construction and operations materials coming from the east or 

west on I-80 would travel through Rawlins to access US 287, and a portion of the project’s construction 

and operations workforce would likely reside in Rawlins. Both of these scenarios would result in 

cumulative transportation effects within the city if the Lost Creek project’s construction schedules were to 

coincide with natural gas development within the CD-C project area. Given the relatively minor increases 

in CD-C-related traffic anticipated for US 287, no substantial adverse cumulative impacts are anticipated. 

Development associated with the previously approved Atlantic Rim Natural Gas Field Development 

Project would also use WY 789 to access the western portions of its project area. Cumulative 

transportation impacts would be anticipated for WY 789 between Creston Junction and Baggs, 

particularly during periods when market conditions promote higher levels of new development activity in 

the Atlantic Rim and CD-C project areas. Under an accelerated drilling scenario, periods of traffic 

impedance and congestion could be anticipated, particularly around the Dad area. 

All of the natural gas projects listed in Table 5.0-1 would generate additional traffic on I-80. If there were 

a regional acceleration of drilling and development in response to sustained high sales prices for natural 

gas, those increases could be substantial. 

5.17 NOISE 

The CIAA for the discussion of Noise is limited to the CD-C project area due to the localized nature of 

this issue. Noise will continue to be generated by project area operations for the life of the field. 

Cumulative impacts of the Proposed Action and action alternatives include the addition of developmentand production-related noise sources to those that already exist within the project area. These noise 

sources include, but are not limited to the I-80 corridor, the railroad, gas compression, fluid transport by 

truck, gas-stabilization equipment, hydrocarbon production, and maintenance activities. In some areas the 

density of development could be considered by some individuals to be “noisy.” This continual (though 

likely low-level) noise may be disruptive or objectionable to individuals such as recreationists or livestock 

operators and may result in displacement of such activities. Displacement of wildlife in general and 

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sensitive wildlife species may also occur in “busy” or “noisy” areas in the greater CD-C fielddevelopment area; refer to Sections 5.8 and 5.9 for this discussion. 

 MANAGEMENT ENVIRONMENT 

5.18 RANGE RESOURCES 

The CIAA for range management includes the entire area of all of the allotments that are located within or 

partially within the CD-C project area. The number of well pads projected for the action alternatives 

varies from a high of 8,950 under Alternative A (100-Percent Vertical Drilling) to a low of 4,032 in 

Alternative D (Directional Drilling). Many of the allotments in the southern portion of the CD-C project 

area cross the project boundary into other natural gas developments (Atlantic Rim on the east and 

Desolation Flats on the west). One allotment managed by the Rock Springs Field Office has minimal 

acreage within the CD-C project area, as well as acreage in the Luman Rim natural gas project. 

Those allotments that cross into the other project areas would have impacts from both natural gas projects 

including forage loss, reduced palatability of forage from dust, potential damage to fences and other 

improvements, possible increase in invasive plant species that can out-compete native vegetation and 

poison sheep, possible collisions, and increased difficulty in management of stock (gates left open, etc.). 

Depending on the location of well pads and the number of locations and associated facilities, some of the 

allotments may reach the level of significance for loss of AUMs described in Section 4.18.2. Surfacedisturbance totals described in Table 3.18-2 would likely be higher for allotments that are affected by 

developments in addition to the CD-C project. It is possible that in these allotments, the combination of 

impacts from several projects could result in the loss of AUMs that reached the level of significance, 

which if not mitigated by range-improvement projects, could result in a reduced number of livestock 

being permitted on the allotment. 

Construction of the three transmission lines planned to cross the CD-C project area and development of 

adjacent oil and gas fields may cause many of the same indirect impacts identified above and would 

increase overall impacts on the affected allotments. 

5.19 OIL AND GAS AND OTHER MINERALS 

The CIAA for oil and gas and other minerals is southwestern Wyoming. The natural gas fields of the CDC project area make up the largest single—but not the only—source of oil and gas in the analysis area. 

The Atlantic Rim, Desolation Flats, Luman Rim, Table Rock, Moxa Arch, and Hiawatha project areas are 

among the other sites of fluid mineral development in the analysis area. The production from all these 

project areas is transported out of the analysis area by pipeline to national markets. Many of the same 

Operators that develop natural gas in the CD-C project area also work in other fields in the analysis area. 

Employees, facilities, and infrastructure of one Operator are often utilized in support of various projects 

within the analysis area. 

5.20 HEALTH AND SAFETY 

The cumulative impacts analysis area for the discussion of Health and Safety includes all Reasonably 

Foreseeable Future Actions listed in Table 5.0-1. Two aspects of safety—increased traffic and additional 

natural gas pipeline construction—are common to all activities across southern Wyoming. These issues 

are long-term in duration and would continue as part of project area operations for the life of the field, 

approximately 45 to 55 years. 

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CHAPTER 5—CUMULATIVE IMPACTS 

Cumulative impacts of the Proposed Action would include the addition of vehicles associated with natural 

gas development and the other reasonably foreseeable activities to the interstate highway and local road 

systems. The additive number of semi-truck rigs and passenger vehicles would add to the risk of collision 

for the project workforce as well as the general public. I-80 will continue to be a major east/west 

transportation corridor for all aspects of transportation including materials needed for continued gas-field 

development and operations, as well as transportation of materials from the field including produced 

condensate, produced water, and solid wastes; refer to Section 5.16 Transportation and Access for this 

discussion. 

Natural gas pipelines may be constructed or enlarged to accommodate the volume of gas being produced 

across the southern tier of Wyoming. Conversely, as fields are depleted, gas production declines and 

pipelines may be abandoned; refer to Section 5.16 for this discussion. 

5.21 WASTE AND HAZARDOUS MATERIALS MANAGEMENT 

The cumulative impacts analysis area for the discussion of Waste and Hazardous Materials Management 

includes all Reasonably Foreseeable Future Actions listed in Table 5.0-1. Wastes will continue to be 

generated and hazardous materials will continue to be used in the project area operations for 

approximately 45 to 55 years, the anticipated life of the field. 

Cumulative impacts of the Proposed Action include: the addition of wastes generated from 15 years of 

operating man camps, drilling and completion of 8,950 additional wells, and the associated produced 

water. Over its lifetime the project would add significantly to the volume of solid waste, drilling and 

completion operations wastes, and produced water, as well as to the wastes generated from well-site and 

pipeline compression and liquids stabilization facilities. The need to appropriately dispose of these wastes 

would significantly stress the existing permitted capacity of local municipal and third-party disposal 

facilities and would necessitate the permitting and construction of additional disposal facilities in 

proximity to the project area. The cumulative impacts would be similar for all the analyzed alternatives, 

although at a reduced level for the No Action alternative. 

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6. CONSULTATION AND COORDINATION 

6.1 INTRODUCTION 

An EIS must be prepared when a federal government agency considers approving an action within its 

jurisdiction that may impact the human environment. An EIS aids federal officials in making decisions by 

presenting information on the physical, biological, and social environment of a proposed project and its 

alternatives. The first step in preparing an EIS is to determine the scope of the project, the range of action 

alternatives, and the impacts to be included in the document. 

The Council on Environmental Quality regulations (40 CFR Parts 1500–1508) require an early scoping 

process to determine the issues related to the Proposed Action and alternatives that the EIS should 

address. The purpose of the scoping process is to identify important issues, concerns, and potential 

impacts that require analysis in the EIS and to eliminate insignificant issues and alternatives from detailed 

analysis. 

This EIS was prepared by the BLM RFO in Rawlins, Wyoming. A third-party contractor was used by the 

BLM to conduct studies, gather data, and prepare documents. Cooperating agencies for the Continental 

Divide-Creston project include the State of Wyoming, Sweetwater County, Little Snake River 

Conservation District, and the Sweetwater County Conservation District. 

6.2 PUBLIC PARTICIPATION 

The scoping process for this project is described in detail in Section 1.9, Public Participation, beginning 

on page 1-12 of this EIS. 

During preparation of the EIS, the BLM and the consultant interdisciplinary team (IDT) have 

communicated with, and received or solicited input from, cooperating agencies; other federal, state, 

county, and local agencies; elected representatives; environmental and citizen groups; industries; and 

individuals potentially concerned with issues regarding the Proposed Action. The contacts made are 

summarized in the following sections. The following organizations/individuals either provided comment 

or were provided the opportunity to comment during the scoping period. 

Federal Offices 

U.S. Army Corps of Engineers 

U.S. Bureau of Reclamation 

U.S. Department of Interior, Bureau of Land Management, Wyoming State Office 

U.S. Environmental Protection Agency 

U.S. Fish and Wildlife Service 

U.S. Congresswoman Barbara Cubin 

U.S. Senator John Barrasso 

U.S. Senator Michael B. Enzi 

State of Wyoming 

Governor Matt Mead 

Governor’s Planning Office 

State Representatives Stan Blake, Bernadine Craft, Allen Jaggi, and Bill Thompson 

State Senators John Hastert, Marty Martin, and Bill Vasey 

Wyoming Department of Agriculture 

Wyoming Department of Environmental Quality 

Wyoming Department of Family Services, Carbon and Sweetwater County offices 

Wyoming Department of Transportation 

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CHAPTER 6—CONSULTATION AND COORDINATION 

Wyoming Game and Fish Department 

Wyoming State Engineer’s Office 

Wyoming State Historic Preservation Office 

Wyoming State Planning Coordinator 

Wyoming Oil and Gas Conservation Commission 

Carbon County 

Comprehensive Planning Consultant 

Department of Planning & Development 

Emergency Management 

Road and Bridge Department 

Sheriff’s Office 

Weed and Pest Control 

Sweetwater County 

Board of County Commissioners 

Community Development Division 

County Engineer 

Emergency Management 

Road and Bridge Department 

Sheriff’s Office 

Municipalities 

City of Green River 

 Community Development 

 Fire Department 

 Police Department 

 Public Works 

City of Rawlins 

 City Manager 

 Fire Department 

 Police Department 

 Planning Department 

 Public Works 

 City Housing Consultant (Kirkham & Associates) 

City of Rock Springs 

 Fire Department 

 Police Department 

 Planning Department 

 Public Services 

 Wastewater Treatment 

Town of Baggs 

 Mayor 

 Town Clerk 

 Utility Engineering Contractor (Lidstone & Associates) 

Town of Bairoil 

 Mayor 

Town of Dixon 

Town of Sinclair 

 Mayor 

6-2 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
 

 

CHAPTER 6—CONSULTATION AND COORDINATION
 

Town of Wamsutter 

 Community Development 

 Town Clerk 

Native American Tribes 

Northern Arapahoe Tribal Council 

Shoshone-Arapahoe Joint Tribal Council 

Shoshone Tribal Council 

Uinta-Ouray Tribal Council 

Ute Mountain Tribe 

Ute Tribal Council 

Grazing Permittees 

Lease and Right-of-Way Holders 

Landowners 

Other Agencies, Industry Representatives, Individuals, and Organizations 

Carbon County Economic Development Corporation 

Carbon County Higher Education Center, Baggs 

Carbon County School District #1 

Carbon County Senior Services, Inc. 

ESS Support Services, Wamsutter Base Camp 

Memorial Hospital of Carbon County 

Memorial Hospital of Sweetwater County 

Noyes Medical Clinic, Baggs 

Rawlins Main Street Downtown Development Authority 

Rock Springs Chamber of Commerce 

Sweetwater County Joint Travel and Tourism Board 

Sweetwater County School District #1 

Sweetwater County School District #2 

Sweetwater County Solid Waste Disposal District #1 

Sweetwater County Solid Waste Disposal District #2 

Sweetwater Economic Development Association 

University of Wyoming Cooperative Extension 

Wyoming State Grazing Board 

Wyoming Tourism Board 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 6-3 
 

CHAPTER 6—CONSULTATION AND COORDINATION 

6.3 LIST OF PREPARERS 

The following tables identify the BLM IDT (Table 6.3-1) and the consultant IDT (Table 6.3-2) that were 

principally involved with preparing this EIS. 

Table 6.3-1. Rawlins Field Office Interdisciplinary Team 

Name Responsibility 

Dave Simons Team Lead 

Lynn McCarthy GIS 

Rhen Etzelmiller Wildlife Biologist 

Mary Read Wildlife Biologist 

Jennifer Fleuret Hydrology 

David Hullum Recreation / Visual Resources 

Patrick Lionberger Fisheries 

Susan Foley Soils / Weeds 

Bonni Bruce Archeology 

Nina Trapp Archeology 

Mike Calton Range Conservationist 

Cheryl Newberry Range Conservationist 

Ray Ogle Reclamation Specialist 

Annette Treat Realty Specialist 

Mark Newman Geologist 

Jerry Dickinson Petroleum Engineer 

Melanie Mirati Wild Horse Specialist 

Ben Smith Wild Horse Specialist 

Nyle Layton HazMat Specialist 

Serena Baker Public Affairs 

6-4 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
 

CHAPTER 6—CONSULTATION AND COORDINATION
 

Table 6.3-2. Consultant Interdisciplinary Team 

Name Affiliation Responsibility 

Gary Holsan Gary Holsan Environmental Planning Interdisciplinary Team Leader, Project Manager 

Steve Moore Gary Holsan Environmental Planning Assistant Project Manager 

Linda Schuemaker Otak, Inc. Writer/Editor, Project Coordinator 

Larry Bennett Integrated Technologies Vegetation and Wetlands, Special Status Plants, 

Reclamation, Range Resources 

Jim Mudd Hayden-Wing Associates, LLC GIS, Data Management 

Connie Hedley Hayden-Wing Associates, LLC Project Coordination for Biological Sciences and 

Mapping 

Sue Moyer Gary Holsan Environmental Planning Wildlife, Special Status Species 

Ben Parkhurst HAF, Inc. Fisheries 

Jana Pastor Western Archeology Services Cultural/Historical Resources 

Renee Taylor Taylor Environmental Consulting, LLC Hazardous Materials, Health and Safety, Noise, 

Wildlife, Special Status Species 

George Blankenship 

Ron Dutton 

Blankenship Consulting, LLC Socioeconomics, Transportation 

Lloyd Levy Lloyd Levy Consulting Visual Resources and Recreation 

Jim Zapert 

Susan Connell 

Brian Mitchell 

Carter Lake Consulting Air Quality 

Dave Cameron KC Harvey, LLC Soils 

Gustav Winterfeld E-V Geological Geology, Paleontology, Minerals 

Mike Evers 

John Berry 

WWC Engineering Water Resources 

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7-38 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
 

8. GLOSSARY 

abandon: To cease producing oil or gas from a well when it becomes unprofitable. Usually, some of the 

casing is removed and salvaged, and one or more cement plugs placed in the borehole to prevent 

migration of fluids between formations. 

acre-foot or acre-feet (ac-ft): The volume of water that covers an area of one acre to a depth of one foot 

(43,560 cubic feet or 325,851 gallons). 

ad valorem: Levied according to assessed value. 

affected environment: The resource values potentially affected by the Proposed Action and alternatives 

analyzed in a NEPA document. 

air quality: The properties and degree of purity of air to which people and natural and heritage resources 

are exposed (National Park Service website <http://www2.nature.nps.gov/air/ AQBasics/glossary.htm>). 

algal: Of, pertaining to, or composed of algae. 

alkaline: Having the quality of a base (pH of 7.0 or greater). 

allotment: An area of land where one or more permittees graze their livestock. Generally consists of 

public land but may include parcels of private or state lands. The number of livestock and season of use 

are stipulated for each allotment. An allotment may consist of several pastures or be only one pasture. 

alluvium: Clay, silt, sand, and gravel or other rock material transported by flowing water and deposited 

as sorted or semi-sorted sediments. 

ambient: The environment as it exists at the point of measurement and against which changes or impacts 

are measured. 

ambient air: The portion of the atmosphere, external to buildings, to which the public has general access 

(40 CFR 50). 

ambient concentration: The mass of a pollutant in a given volume of air, typically measured as 

micrograms of pollutant per cubic meter of air. 

ambient standards: The absolute maximum level of a pollutant allowed to protect either public health 

(primary) or welfare (secondary). 

American Petroleum Institute (API): API is the governing authority on oil industry standards and 

practices. “API Gravity” is a reference system for the density of crude oils and constituent hydrocarbons. 

ancillary facilities: Facilities often required in an oil and gas field other than the wells and pipelines, 

such as compressor stations. 

animal unit month (AUM): A standardized unit of measurement of the amount of forage necessary for 

the sustenance of one animal unit for 1 month; also, a unit of measurement that represents the privilege of 

grazing one animal unit for 1 month. 

anticline: A geological formation described usually as a dome or inverted saucer. If covered by an 

impermeable layer of rock, the anticline is a potential oil or gas reservoir. 

Application for Permit to Drill (APD): The Department of the Interior’s application permit form to 

authorize oil and gas drilling activities on federal land or mineral estate. 

aquifer: A water-bearing bed or layer of permeable rock, sand, or gravel capable of yielding water. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 8-1 
 

 

GLOSSARY
 

aquitard: A bed of low permeability adjacent to an aquifer that may serve as a storage unit for 

groundwater, although it does not readily yield water. 

archaeological: The scientific studies of past peoples and cultures by analysis of physical remains 

(artifacts). 

Aridosols: Soils formed in arid climates; they are often dry and have little organic accumulation in the 

upper layers. 

arkose: a sedimentary rock, specifically a type of sandstone that contains at least 25% feldspar. 

area of critical environmental concern (ACEC): An area on public lands designated for special 

management to protect and prevent irreparable damage to important historic, cultural, or scenic values, 

fish and wildlife resources, or other natural systems or processes or to protect life and safety from natural 

hazards. 

background concentration: The existing levels of air pollutant concentration in a given region. In 

general, it includes natural and existing emission sources but not future emission sources. 

badland: Steep or very steep, commonly non-stony barren land dissected by many intermittent drainage 

channels. Badland is most common in semi-arid and arid regions where streams are entrenched in soft 

geologic material. Runoff potential is very high, and geologic erosion is active in such areas. 

berm: A raised area with vertical or sloping sides. 

biodiversity: The variety of plant and animal life on a given area. 

borehole: The circular hole made by drilling, extending from the surface to the gas resource to be 

recovered. 

brush hog: A heavily built rotary-type mower that is typically attached to the back of a farm tractor, with 

dull blades that are propelled outward by centrifugal force, installed on hinges so that they bounce 

backward and inward if they hit a rock or stump. 

calcareous: Containing calcium carbonate. 

capability: In the context of the Standards for Healthy Rangelands for the Public Lands Administered by 

the Bureau of Land Management in the State of Wyoming, the highest ecological status a riparianwetland area can attain given political, social, or economical constraints (i.e., human-caused limiting 

factors). 

casing: Steel pipe placed in an oil or gas well to prevent the hole from collapsing. 

CD-C consultation group: An interagency group that BLM would consult on implementation of the CDC Preferred Alternative. 

cement: Cement is used to “set” casing in the well bore and to seal off unproductive formations and 

apertures. 

collector roads: BLM roads that provide primary access to large blocks of land and connect with, or are 

extensions of, a public road system. 

colluvium: A general term applied to loose and incoherent deposits, usually at the foot of a slope or cliff 

and brought there chiefly by gravity. 

completion: The activities and methods to prepare a well for production. Includes installation of 

equipment for production from an oil or gas well. 

condensate (gas condensate): Hydrocarbons (oil) contained in the natural gasstream, often removed by 

condensation. 

8-2 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
 

GLOSSARY
 

conditions of approval (COAs): A set of restrictions, or conditions, included in the approval of a federal 

permit, including NEPA documents. 

conglomerate: Rounded water-worn fragments of rock or pebbles cemented together by another mineral 

substance. 

conglomeratic: Sandstones derived from rounded water-worn fragments of rocks or pebbles. 

contrast: The effect of a notable difference in the form, line, color, or texture of the landscape features 

within the area being viewed. 

Controlled Surface Use (CSU): A category of stipulation that allows some use and occupancy of public 

land while protecting identified resources or values. A CSU stipulation identifies the location protected, 

activities prohibited or restricted, and the resources protected. The extent of protection may range from a 

limited area for only one activity to all uses. 

corridor: A narrow strip of land. 

corvid: A member of the crow family (corvidae), which includes ravens, rooks, jackdaws, jays, magpies, 

treepies, choughs, and nutcrackers. 

Council on Environmental Quality (CEQ): An advisory council to the President established by the 

National Environmental Policy Act of 1969. It reviews federal programs for their effect on the 

environment, conducts environmental studies, and advises the President on environmental matters. 

Cretaceous era: The latest system of rocks or period of the Mesozoic era, between 136 and 65 million 

years ago. 

criteria pollutants: Air pollutants for which the EPA has established state and national ambient air 

quality standards. These include particulate matter (PM), nitrogen oxides (NOX), sulfur dioxide (SO2), 

carbon monoxide (CO), and volatile organic compounds (VOCs). 

critical elements of the human environment: A list of resource concerns that must be addressed in 

every NEPA document. 

crucial range: Any particular seasonal range or habitat component that has been documented as the 

determining factor in a population’s ability to maintain itself at a certain level over the long-term. 

cubic feet per second (cfs): The rate of discharge representing a volume of 1 cubic foot of water passing 

a given point during 1 second. 

cubic foot: The volume of gas contained in one cubic foot of space at a standard pressure base of 14.7 

pounds per square inch and a standard temperature base of 60 °F. 

cuesta: A geological term dscribing an asymmetric ridge formed by gently tilted hard rock layers. Every 

cuesta has a steep slope, where the rock layers are exposed on their edges, called an escarpment or, if 

more severe, a cliff. Usually an erosion-resistant rock layer, a cuesta also has a long, more gentle slope on 

the other side of the ridge called a “dip slope.” 

cultural resources: The physical remains of human activity (artifacts, ruins, burial mounds, petroglyphs, 

etc.) and the conceptual content or context (as a setting for legendary, historic, or prehistoric events, such 

as a sacred area of native peoples, etc.) of an area of prehistoric or historic occupation. 

culvert: A drain or conduit often under a road. 

cumulative impact: The impact on the environment that results from the incremental impact of the action 

when added to other past, present, and reasonably foreseeable future actions regardless of what agency 

(federal or non-federal) or person undertakes such other actions. Cumulative impacts can result from 

individually minor but collectively significant actions taken place over a period of time (40 CFR 1508.7). 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 8-3 
GLOSSARY
 

cuttings: The material removed from the borehole by the drill bit and lifted to the surface. 

decibel: A unit of measurement of noise intensity. The measurements are based on the energy of the 

sound waves and units are logarithmic. Changes of 5 decibels or more are normally discernible to the 

human ear. 

deciduous: Trees or shrubs that lose their leaves each year during a cold or dry season. 

deciview: The unit of measurement of haze developed to uniformly describe levels of monitored and 

modeled visibility impairment. A delta deciview is a change in haze index calculated between baseline 

haze levels and predicted future levels. 

delta: An alluvial deposit, usually triangular, at the mouth of a river. 

deltaic: Related to or like a delta. 

diffusion: A process by which substances are transferred from regions of higher concentrations to regions 

of lower concentrations (National Park Service website <http://www2.nature. 

nps.gov/air/AQBasics/glossary.htm>). 

directional drilling: The intentional deviation of a wellbore from vertical to reach subsurface areas off to 

one side from the surface drilling site. 

discharge: The volume of water flowing past a point per unit time, commonly expressed as cubic feet per 

second (cfs), gallons per minute (gpm), or million gallons per day (mgd). 

dispersion: The spreading out of pollutants. Generally used to show how much an air pollutant will 

spread from a particular point. 

displacement: As applied to wildlife, forced shifts in the patterns of wildlife use, either in location or 

timing of use. 

disposal well: A well into which produced water from other wells is injected into an underground
 

formation for disposal. 

dissolved solids: The total amount of dissolved material, organic and inorganic, contained in water or 

wastes. 

diversity: The distribution and abundance of different plant and animal communities and species. 

drainage: Natural channel through which water flows some time of the year. Natural and artificial means 

for effecting discharge of water as by a system of surface and subsurface passages. 

drill rig: The mast, draw works, and attendant surface equipment of a drilling unit. 

drilling fluid: Fluid used to lubricate and cool the drill bit, to assist in lifting cuttings from the borehole, 

and to control pressures in the borehole. 

drilling mud: The circulating fluid used to bring cuttings out of the well bore, to cool the drill bit, and to
 

provide hole stability and pressure control. Drilling mud includes a number of additives to maintain the 

mud at desired viscosities and weights. Some additives that may be used are caustic, toxic, or acidic. 

drought: Prolonged dry weather (precipitation less than 75 percent of average annual amount). 

ecosystem: An interacting system of organisms considered together with their environment (e.g., forest, 

marsh, and stream ecosystems). 

edaphic: Relating to soil, especially as it affects living organisms. Edaphic characteristics include such 

factors as water content, acidity, aeration, and the availability of nutrients. 

emergent vegetation: Erect, rooted, herbaceous plants that project out of or emerge from the water. 

8-4 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
GLOSSARY
 

emission factor: An empirically derived mathematical relationship between pollutant emission rate and 

some characteristic of the source such as volume, area, mass, or process output. 

emission: Air pollution discharge into the atmosphere, usually specified by mass per unit time. 

Endangered species (animal): Any animal species in danger of extinction throughout all or a significant 

portion of its range. This definition excludes species of insects that the Secretary of the Interior 

determines to be pests and whose protection under the Endangered Species Act of 1973 would present an 

overwhelming and overriding risk to man. 

Endangered species (plant): Species of plants in danger of extinction throughout all or a significant 

portion of their ranges. Existence may be endangered because of the destruction, drastic change, or severe 

curtailment of habitat or because of over exploitation, disease, predation, or even unknown reasons. Plant 

taxa from limited areas (e.g., the type localities only) or from restricted fragile habitats usually are 

considered endangered. 

environment: The aggregate of physical, biological, economic, and social factors affecting organisms in 

an area. 

environmental impact statement (EIS): An analysis of alternative actions and their predictable 

environmental impacts, including physical, biological, economic, and social consequences and their 

interactions; short-and long-term impacts; and direct, indirect, and cumulative impacts. 

Eocene: 1) The next to the oldest of the five major epochs of the Tertiary period in the Cenozoic era. 2) 

The series of strata deposited during that epoch. 

eolian: The erosive action of the wind and deposits that are transported by the wind. 

ephemeral drainage: A drainage area or a stream that has no base flow. Water flows for a short time 

each year but only in direct response to rainfall or snowmelt events. 

epicenter: The portion of the earth’s surface directly above the focus of an earthquake. 

erosion: The removal, detachment, and entrainment of earth materials by weathering, dissolution, 

abrasion, and corrosion, later to be transported by moving water, wind, gravity, or glaciers. 

fault: A fracture in bedrock along which there has been vertical and/or horizontal movement caused by
 

differential forces in the earth’s crust. 

federal lands: All lands and interests in lands owned by the U.S., which are subject to the mineral leasing 

laws, including mineral resources or mineral estates reserved to the U.S. in the conveyance of a surface or 

non-mineral estate. 

feral: having reverted to the wild state; not domesticated; as in feral (or wild) horses. 

field: 1) A set of rocks containing hydrocarbons. 2) An oil and gas reservoir. 

flare: Process that burns and evacuates unused gases. 

floodplain: That portion of a river valley, adjacent to the channel, which is built of recently deposited 

sediments and is covered with water when the river overflows its banks at flood stages. 

fluvial: Of or pertaining to rivers. 

forage: Vegetation of all forms available for animal consumption. 

forb: A broad-leafed flowering herb other than grass. 

formation: A rock/mineral deposit or structure covering an area with the same physical properties. 

fracing (fracturing): A method of stimulating well production by increasing the permeability of the 

producing formation. Under extremely high hydraulic pressure, the fracturing fluid (water, oil, dilute 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 8-5 
 

GLOSSARY
 

hydrochloric acid, or other fluid) is pumped into the formation that parts or fractures it. Proppants or 

propping agents such as sand or glass beads are pumped into the formation as part of the fracturing job. 

The proppants become wedged in the open fractures, leaving channels for oil or gas to flow into the well 

after the hydraulic fracture pressure is released. This process is often called a “frac job.” When high 

concentrations of acid are used, it may be called an “acid frac job.” 

fugitive dust: Airborne particles emitted from any source other than through a controllable stack or vent. 

gathering pipelines: Pipelines within a field that transport gas or oil from the well to a central production 

facility or to the point of sale. 

Global Positioning System (GPS): Computer software that records and stores coordinates for positions 

on earth via satellite. 

gravitational acceleration constant (g): The indication of the intensity of a gravitational 

field. Expressed in meters per second squared (m/s2

), at the surface of the earth, 1 g is about 9.8 m/sec2. 

As an example 5%g means that motion of 5% x 9.8 m/sec2 can be expected. 

groundwater: Water contained in the pore spaces of consolidated and unconsolidated material. 

habitat: A specific set of physical conditions that surround a single species, a group of species, or a large 

community. In wildlife management, the major components of habitat are considered to be food, water, 

cover, and living space. 

habitat function: The arrangement of habitat features and capability of those features to sustain species, 

population, and diversity of wildlife over time. 

Holocene: That period of time (epoch) since the last ice age; also the series of strata deposited during that 

epoch. 

human environment: The factors that include but are not limited to biological, physical, social, 

economic, cultural, and aesthetic factors that interrelate to form the environment. 

hydraulic conductivity: The rate of water flow in gallons per day through a cross-section of 1 square 

foot under a unit hydraulic gradient at the prevailing temperature of 60oF. 

hydrocarbon: A compound formed from carbon and hydrogen, for example oil and gas. 

hydrology: A science that deals with the properties, distribution, and circulation of surface and 

subsurface water. 

hydrostatic testing: Testing of the integrity of a newly placed but uncovered pipeline for leaks. The 

pipeline is filled with water and pressurized to operating pressures, and the pipeline is visually inspected. 

impacts: These include a) direct impacts, which are caused by the action and occur at the same time and 

place and b) indirect impacts, which are caused by the action and are later in time or farther removed in 

distance but are still reasonably foreseeable. Indirect impacts may include growth-inducing impacts and 

other impacts related to induced changes in the pattern of land use, population density, or growth rate and 

related impacts on air and water and other natural systems, including ecosystems. Impacts include 

ecological (such as the effects on natural resources and on the components, structures, and functioning of 

affected ecosystems), aesthetic, historic, cultural, economic, social, or health, whether direct, indirect, or 

cumulative. Impacts may also include those resulting from actions which may have both beneficial and 

detrimental impacts, even if on balance the agency believes that the impact will be beneficial (40 CFR 

1508.8). 

impermeable: Not permitting the passage of a fluid. 

impoundment: The accumulation of any form of water in a reservoir or other storage area. 

8-6 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
 

GLOSSARY
 

increment: Incremental standards (prevention of significant deterioration [PSD]) are the maximum 

amounts of pollutants allowed above the baseline in regions of clean air. 

infiltration: The movement of water or some other liquid into the soil or rock through pores or other 

openings. 

infrastructure: The basic framework or underlying foundation of a community including road networks, 

electric and gas distribution, water and sanitation services, and facilities. 

injection well: A well that is used to inject produced water from drilling operations in order to maintain 

pressure or to bring a field back under pressure. 

intensive managmeent. Management that includes the use of proper distance restrictions, mitigation 

stipulations, seasonal or timing restrictions, rehabilitation standards, reclamation measures, use of Best 

Management Practices, and the application of the Wyoming Mitigation Guidelines for Surface Disturbing 

and Disruptive Activities to adequately protect the resources for which the intensive management is 

applied. Intensive management actions would be applied with the goal of maintaining or enhancing 

sensitive resources (i.e., plant communities, wildlife habitat, soils, water, archeological or paleontological 

resources, etc.). Management may include attaching conditions of approval to specific projects or 

additional planning recognizing the unique resources for which the area is managed; typically these would 

be more restrictive then standard management and would be designed for specific projects and locations. 

interdisciplinary team (IDT): A group of federal and cooperating agencies selected to work within the 

NEPA process in scoping, analysis, and document preparation. The purpose of the team is to integrate its 

collective knowledge of the physical, biological, economic, and social sciences and the environmental 

design arts into the environmental analysis process. Interaction among team members often provides 

insight that otherwise would not be apparent. 

interim reclamation: Reclamation initiated on well pads, roads, and pipelines after drilling activity is 

completed and wells are in production. Interim reclamation is considered successful when reclamation 

performance objectives are met. 

intermittent stream: A stream or reach of a stream that is below the local water table for at least some 

part of the year and obtains its flow from both surface runoff and groundwater discharge. 

intertongue: Irregular/overlapping boundaries among rock formations. 

intervisible turnout: a turnout on a local or BLM road where approaching drivers have a clear view of 

the section of road between the two turnouts and can pull off to the side to let the approaching driver pass 

invasive species: a species that is not native (or is alien) to the ecosystem under consideration and whose 

introduction causes or is likely to cause economic or environmental harm or harm to human health 

(Executive Order 13112). 

irretrievable: A term that applies to the loss of production, harvest, or use of natural resources. For 

example, some or all of the timber production from an area is lost irretrievably while an area is serving as 

a winter sports site. The production lost is irretrievable, but the action is not irreversible. If the use 

changes, it is possible to resume timber production. 

irreversible: A term that describes the loss of future options. Applies primarily to the effects of use of 

nonrenewable resources, such as minerals or cultural resources, or to those factors, such as soil 

productivity, that are renewable only over long periods of time. 

isopach: A contour that connects points of equal thickness. Commonly, the isopachs, or contours that 

make up an isopach map, display the stratigraphic thickness of a rock unit as opposed to the true vertical 

thickness. Isopachs are true stratigraphic thicknesses; i.e., perpendicular to bedding surfaces. 

lacustrine: Pertaining to, produced by, or formed in a lake or lakes. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 8-7 
GLOSSARY
 

land use: The types of activities allowed (e.g., mining, agriculture, timber production, residential, 

industrial). 

landslide: A perceptible downhill sliding or falling of a mass of soil and rock lubricated by moisture or 

snow. 

lease: 1) A legal document that conveys to an operator the right to drill for oil and gas. 2) The tract of 

land on which a lease has been obtained, where producing wells and production equipment are located. 

lek: A traditional courtship display attended by male greater sage-grouse in or adjacent to sagebrushdominated habitat. Leks are categorized as: 

Active: Any lek that has been attended by male greater sage-grouse during the strutting season. 

Inactive: Leks where it is known that there was no strutting activity through the course of a strutting 

season. 

Unknown: Leks that have not been documented either active or inactive during the course of a 

strutting season. 

Occupied: A lek that has been active during at least one strutting season within the last 10 years. 

Unoccupied (formerly termed “historical lek”:) There are two types of unoccupied leks: (1) 

Destroyed -a formerly active lek site and surrounding sagebrush habitat that has been destroyed and is 

no longer capable of supporting greater sage-grouse breeding activity. (2) Abandoned -a lek in 

otherwise suitable habitat that has not been active during a consecutive 10-year period. 

Undetermined: Any lek that has not been documented as being active in the last 10 years but that 

does not have sufficient documentation to be designated unoccupied. 

Life of project: Begins with the first disturbance authorized under the ROD for this project and ends 

when all wells are plugged and abandoned and all surface disturbance (each disturbed site) meets the 

reclamation performance objectives. 

lithic scatter: A surface scatter of cultural artifacts and debris that consists entirely of lithic (i.e., stone) 

tools and chipped stone debris. This is a common prehistoric site type that is contrasted to a cultural 

material scatter (which contains other or additional artifact types such as pottery or bone artifacts), or to a 

camp (which contains habitation features, such as hearths, storage features, or occupation features), or to 

other site types that contain different artifacts or features. 

lithology: The description of the physical character of a rock as determined by eye or with a low-powered 

magnifier, based on color, structures, mineralogic components, and grain size. 

loam: A mixture of sand, silt, and clay containing between 7 and 27 percent clay, 28 to 50 percent silt and 

less than 50 percent sand. 

local roads: BLM roads that provide primary access to large blocks of land and connect with or are 

extensions of a public road system. 

Loess: a geologic term that refers to deposits of silt (sediment with particles 2–64 microns in diameter) 

that have been laid down by wind action. 

log: A systematic recording of data, as from the driller’s log, mud log, electrical well log, or radioactivity 

log. Many different logs may be run to obtain various characteristics of down-hole formations. 

long-term impacts: For the purpose of this NEPA analysis, long-term impacts last for the life of the 

project or beyond. 

migrate: To pass periodically from one region or climate to another. 

8-8 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
GLOSSARY
 

mineral rights: Reserved mineral rights are the retention of ownership of all or part of the mineral rights 

by a person or party conveying land to the United States. Conditions for exercising these rights have been 

defined in the Secretary’s Rules and Regulations to Govern Exercising of Mineral Rights Reserved in 

Conveyances to the United States attached to and made a part of deeds reserving mineral rights. 

mitigate: To lessen the severity. 

mitigation: Avoiding the impact altogether by not taking a certain action or parts of an action; 

minimizing impacts by limiting the degree of magnitude of the action and its implementation; rectifying 

the impact by repairing, rehabilitating, or restoring the affected environment; reducing or eliminating the 

impact over time by preservation and maintenance operations during the life of the action; and/or 

compensating for the impact by replacing or providing substitute resources or environments. 

mitigation measures: Actions taken to reduce or minimize potential impacts to the environment. 

modeling: A mathematical or physical representation of an observable situation. In air pollution control, 

models afford the ability to predict pollutant distribution or dispersion from identified sources for 

specified weather conditions. 

mollisols: Soil order that has a thick (generally 10-inch), very dark brown to black surface horizon that is 

rich in organic matter (grassland soils common in prairie regions). 

monitor: To systematically and repeatedly watch, observe, or measure environmental conditions in order 

to track changes. 

mud: Mud is drilling fluid that consists mainly of a mixture of water, or oil distillate, and “heavy” 

minerals such as bentonite or barites. 

mud system: A system used to manage suspended mud in the well-drilling process. 

National Ambient Air Quality Standards (NAAQS): The allowable concentrations of air pollutants in 

the air specified by the federal government. The air quality standards are divided into primary standards 

(based on the air quality criteria and allowing an adequate margin of safety and requisite to protect the 

public health) and secondary standards (based on the air quality criteria and allowing an adequate margin 

of safety and requisite to protect the public welfare from any unknown or expected adverse effects of air 

pollutants). 

National Environmental Policy Act of 1969 (NEPA): The federal law established in 1969, which went 

into effect on January 1, 1970, that 1) established a national policy for the environment, 2) requires 

federal agencies to become aware of the environmental ramifications of their Proposed Actions, 3) 

requires full disclosure to the public of proposed federal actions and a mechanism for public input into the 

federal decision-making process, and 4) requires federal agencies to prepare an environmental impact 

statement for every major action that would significantly affect the quality of the human environment. 

National Register of Historic Places: A list of districts, sites, buildings, structures, and objects 

significant in American history, architecture, archaeology, and culture. 

native species: Plants or animals that originated in the area in which they are found (i.e., they naturally 

occur in that area); with respect to a particular ecosystem, a species that, other than as a result of an 

introduction, historically occurred or currently occurs in that ecosystem. 

natural gas: Those hydrocarbons, other than oil and other than natural gasliquids separated from natural 

gas, that occur naturally in the gaseous phase in the reservoir and are produced and recovered at the 

wellhead in gaseous form. 

nephelometric turbidity unit (NTU): A unit measuring the lack of clarity of water, used by water and 

sewage treatment plants; named for the nephelometer used to take the measurement. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 8-9 
 

 

GLOSSARY
 

No Action Alternative: The management direction, activities, outputs, and effects that are likely to exist 

in the future if the current plan would continue unchanged. 

No Surface Occupancy (NSO): A stipulation in a lease that disallows any surface disturbance in the 

lease area at any time. Natural Gas or oil from an NSO area, for instance, would have to be recovered by
 

directional drilling. 

Notice of Intent (NOI): A notice published in the Federal Register to announce the intent to prepare an 

EIS. 

noxious weeds: Officially designated (State of Wyoming-designated, Sublette County-declared) 

undesirable or invading weedy species generally introduced into an area due to human activity. 

oil and gas field: A natural accumulation of oil and gas in the subsurface. Oil and gas may be present in 

two or more reservoirs at different depths. 

oil and gas lease: A federal oil and gas lease is a legal document that gives the lease holder the right to 

explore for and develop any oil and gas that may be present under the area designated in the lease while 

complying with any surface use conditions which may have been stipulated when the lease was issued. 

ozone (O3): A molecule containing three oxygen atoms produced by passage of an electricalspark through 

air or oxygen (O2). 

paleontology: The science that deals with the history and evolution of life on earth.particulate matter: A 

particle of soil or liquid matter (e.g., soot, dust, aerosols, fumes, andmist). 

passerine: Passerines are the perching birds, and most are also songbirds. 

perennial stream: A stream or reach of a stream that flows throughout the year. 

perforation: Holes punched in the casing of a well at the pay zone to be produced to allow gas or oil to
 

enter the well. 

permeability: The extent that a substance is open to passage or penetration, especially by fluids. 

permeable: The property or capacity of a porous rock, sediment, or soil to transmit a liquid.
 

permittee (grazing): A person who has livestock grazing privileges on an allotment or allotments within 

the resource area.
 

pH: Measure of acidity or alkalinity
 

phenology: The study of periodic plant and animal life-cycle events that occur periodically, such as 

blossoming or migration, and how these are influenced by seasonal and interannual variations in climate.
 

physiographic province: A region having a pattern of relief features or landforms that differs 

significantly from adjacent regions. 

physiography: The genesis and evolution of landforms. 

playa: The low, flat parts of a basin or other undrained area typically characterized by depressions with 

clay bottoms that pool water on the surface and accumulate salts (see also riparian areas).
 

PM10: Airborne suspended particles with an aerodynamic diameter of 10 microns or less. 

PM2.5: Airborne suspended particles with an aerodynamic diameter of 2.5 microns or less. 

potential: In the context of the Standards for Healthy Rangelands for the Public Lands Administered by
 

the Bureau of Land Management in the State of Wyoming, the highest ecological status a riparianwetland area can attain given no political, social, or economical constraints. 

preferred alternative: The alternative identified in the EIS as the action favored by the agency. 

8-10 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
GLOSSARY
 

prevention of significant deterioration (PSD): A classification established to preserve, protect,and 

enhance the air quality in National Wilderness Preservation System areas in existence prior to August 

1977 and other areas of national significance, while ensuring economic growth can occurin a manner 

consistent with the preservation of existing clean air resources. Specific emission limitations and other 

measures, by class, are detailed in the Clean Air Act (42 U.S.C. 1875 etseq.). 

produced water: Water brought to the surface through the borehole. 

production: Phase of commercial operation of an oil field. 

production casing: Steel pipe installed in the borehole to isolate formations in the borehole and to 

eliminate communication among hydrocarbon-bearing zones and/or water aquifers and othermineral 

resources. 

proppants: Proppants or propping agents are substances such as sand or glass beads that are pumped into 

the formation as part of the fracturing job. The proppants become wedged in the open fractures, leaving 

channels for oil to flow into the well after the hydraulic fracture pressure is released. This process is often 

called a “frac job.” When high concentrations of acid are used, it may be called an “acid frac job” (see 

also fracing/fracturing). 

PSD increments: The maximum allowable increase in pollutant concentrations permitted over baseline 

conditions as specified in the EPA Prevention of Significant Deterioration (PSD) regulations (40 CFR 

Part 52.21). The regulations apply only to areas currently attaining NAAQS/WAAQS. Most National 

Parks and Wilderness Areas are Class I areas, where almost no future pollution increase is permitted. 

Most other areas are Class II areas, where moderate increases in pollution levels are allowed. 

public land: Lands or interests in lands owned by the United States and in this case administered by the 

Secretary of Interior through the Bureau of Land Management, without regard to how the United States 

acquired ownership. 

quaternary: The latest period of time, from the present to 2 million years ago and represented by local 

accumulations of glacial and post-glacial deposits. 

range: Land producing native forage for animal consumption and lands that are revegetated naturally or 

artificially to provide forage cover that is managed like native vegetation, that are amenable to certain 

range management principles or practices. 

raptor: A group of carnivorous birds consisting of hawks, eagles, falcons, kites, vultures, and owls. 

recharge: Replenishment of the water supply in an aquifer through the outcrop or along fracture lines. 

reclamation: Rehabilitation of a disturbed area to make it acceptable for designated uses. This normally 

involves regrading, replacement of topsoil, revegetation, and other work necessary to restore it for use. 

Record of Decision (ROD): A decision document for an EIS or Supplemental EIS that publicly and 

officially discloses the responsible official’s decision regarding the actions proposed in the EIS and their 

implementation. 

reserve pit: An excavated pit that may be lined with plastic that holds drill cuttings and waste mud. 

reserves/recoverable reserves: Areas of mineral-bearing rock from which the mineral can be extracted 

profitably with existing technology and under present economic conditions. 

reservoir: The “pool” of oil or gas that is being tapped. 

residuum: Unconsolidated, weathered, or partly weathered mineral material that accumulates by 

disintegration of bedrock in place. 

resource roads: Spur roads that provide point access, as to a well site, and connect to local or collector 

roads. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 8-11 
 

 

GLOSSARY
 

revegetation: The reestablishment and development of self-sustaining plant cover. On disturbed sites, 

human assistance will speed natural processes by seedbed preparation, reseeding, and mulching. 

rig: A collective term to describe the equipment needed when drilling a well. 

right-of-way: The legal right for use, occupancy, or access across land or water areas for a specified 

purpose or purposes. 

riparian area: A transition between wetlands or water bodies and upland areas. Riparian areas exhibit 

vegetation or physical characteristics that reflect the influence of subsurface water in the root zone. 

Typical riparian areas include lands along, adjacent to, or contiguous with perennially and intermittently 

flowing rivers and streams, glacial potholes, and the shores of lakes and reservoirs with stable water 

levels. Excluded are ephemeral streams or washes that lack vegetation and depend on free water in the 

soil. 

riparian communities. Communities of vegetation associated with either open water or wetlands. 

Examples are cottonwood and willow communities; meadows; aspens near water sources; and other trees, 

grasses, forbs, and shrubs associated with water. 

road metal: the crushed rock used for road beds and surfaces, foundations, and railway embankments, 

among other things 

roosting: To rest or sleep in a roost. A bird will typically use the same roost for an extended period of 

time. 

runoff: That part of precipitation that appears in surface streams. Precipitation that is not retained on the 

site where it falls and is not absorbed by the soil. 

salinity: 1) A measure of the amount of mineral substances dissolved in water; 2) salty. 

scatter (archeological): Archaeological evidence of prior disturbance that is distributed about an area 

rather than concentrated in a single location. 

scope: Extent or range of view. 

scoping: An early and open process for determining the scope of issues to be addressed in an EIS and for 

identifying the significant issues related to a Proposed Action. Scoping may involve public meetings, 

field interviews with representatives of agencies and interest groups, discussions with resource specialists 

and managers, and written comments in response to news releases, direct mailings, and articles about the 

Proposed Action and scoping meetings. 

sediment: Soil or mineral transported by moving water, wind, gravity, or glaciers, and deposited in 

streams or other bodies of water or on land. 

sediment load: The amount of sediment (sand, silt, and fine particles) carried by a stream or river. 

seismic: Pertaining to an earthquake or earth vibration, including those that are artificially induced. 

shale: A laminated sediment in which the constituent particles are predominantly of the clay grade. 

short-term impacts: For the purpose of this analysis, short-term impacts are generally defined as those 

that would last for 5 years or less. 

shrink-swell: Refers to clays or soils that alternately expand and contract in a semiarid climate where 

drying out is possible. 

shut-in: The process of stopping production at an otherwise producing well. 

significant impact: A meaningful standard to which an action may impact the environment. The impact 

may be beneficial, adverse, direct, indirect, or cumulative and may be short-term or long-term. 

8-12 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
 

GLOSSARY
 

silt: Any earthy material composed of fine particles, smaller than sand but larger than clay, suspended in 

or deposited by water. 

slope wash: Soil and rock material that is being or has been moved down a slope predominantly by the 

action of gravity assisted by running water that is not concentrated into channels. 

socioeconomics: Study of an impact region on the current and projected population and relative 

demographic characteristics (housing, economy, government, etc.). 

soil productivity: The capacity of a soil to produce a specific crop such as fiber and forage, under 

defined levels of management. It is generally dependent on available soil moisture, nutrients, and length 

of growing season. 

sole source aquifer: An aquifer that supplies at least 50 percent of the drinking water consumed in the 

area overlying the aquifer. 

spacing: The number of acres per given well in the subsurface. For instance, 160-acre spacing means that 

one well would be drilled in each quarter section (160 acres) or up to four wells per section (640 acres). 

species of concern: Species of concern include federally listed Threatened or Endangered species, 

species proposed for listing, BLM Sensitive Species, WGFD priority species, and species considered rare 

or important by the Wyoming Natural Diversity Database. 

stipulation: A legal requirement, specifically a requirement that is part of the terms of a mineral lease. 

Some stipulations are standard on all federal leases. Other stipulations may be applied to the lease at the 

discretion of the surface management agency to protect valuable surface resources. Stipulations are 

supported by the NEPA process; without NEPA support, a stipulation cannot be added to the lease. 

strata: An identifiable layer of bedrock or sediment. 

stromatolite: a laminated usually mounded sedimentary fossil formed from layers of cyanobacteria, 

calcium carbonate, and trapped sediment. (Merriam-Webster) 

structural basin: A large depression of structural origin. 

substrate: Material consisting of silts, sands, gravels, boulders, and/or woody debris found on the bottom 

of a stream channel. 

surface-disturbing activities: Any authorized action that disturbs vegetation and surface soil, increasing 

erosion potential above normal site conditions. This definition typically applies to mechanized or 

mechanical disturbance. However, intense or extensive use of hand or motorized hand tools may fall 

under this definition. Examples of surface-disturbing activities include construction of well pads and 

roads, pits and reservoirs, pipelines and power lines, mining, and vegetation treatments. 

Tank flashing: Flashing losses occur when a liquid with entrained gases goes from a higher pressure to a 

lower pressure. This occurs when condensate is transferred into a tank. As the pressure on the liquid 

drops, some of the compounds dissolved in the liquid are released, or “flashed.” Increases in the 

temperature of the liquid can also cause flashing losses. 

Taphonomy: The study of the origin and nature of accumulations of fossils, i.e., what happened to an 

organism between the time it died and the time it was buried in sediment that later became lithified rock. 

taxon (plural: taxon): A population, or group of populations of organisms which are usually inferred to 

be phylogenetically related and which have characters in common which differentiate the unit (e.g. a 

geographic population, a genus, a family, an order) from other such units. A taxon encompasses all 

included taxa of lower rank and individual organisms. 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 8-13 
GLOSSARY
 

taxadjunct: a soil that has properties outside the range of any recognized series. Such soils are named for 

a series they strongly resemble and are designated as taxadjuncts to that series because they differ in ways
 

too small to be of consequence in interpreting their use and behavior. 

Tertiary: The older of the two geologic periods comprising the Cenozoic Era; also the system of strata 

deposited during that period. 

Threatened species: Any species (plant or animal) that is likely to become an Endangered species within 

the foreseeable future throughout all or a significant portion of its range. Threatened species are identified 

by the Secretary of the Interior in accordance with the 1973 Endangered Species Act. 

topography: The features of the earth, including relief, vegetation, and waters. 

topsoil: The uppermost layers of naturally occurring soils suitable for use as a plant growth medium. 

total dissolved solids (TDS): Total amount of dissolved material, organic or inorganic, contained in a 

sample of water. 

transpiration: The process by which water vapor escapes from a living plant and enters the atmosphere. 

tuff: A rock formed by compacted volcanic fragments, generally smaller than 4 mm in diameter. 

turbidity: A measurement of the total suspended solids. 

two-track: A road that has not been constructed or maintained but that has been created by repeated use. 

unconformity: A break in the stratigraphic sequence. 

underground source of drinking water: An aquifer that supplies any public water system or contains a 

sufficient quantity of groundwater to supply a public water system or currently supplies drinking water 

for human consumption.
 

understory: A layer of vegetation underlying a layer of taller vegetation, such as brush and grass under 

trees. 

undulate: To move or cause to move with a wavelike motion. 

ustic: Soils that are moist for more than half a year but have a distinct dry season. 

vegetation type: A plant community with visually distinguishable characteristics, named for the apparent 

dominant species. 

viewshed: The areas seen from any given point. 

visibility: Refers to the visual quality of the view or scene in daylight, with respect to color, rendition, 

and contrast definition. The ability to perceive form, color, and texture. 

visual resource: The composite of basic terrain, geologic features, water features, vegetation patterns, 

and land use effects that typify a land unit and influence the visual appeal the unit may have for viewers. 

Visual Resource Management (VRM): A system of visual management used by the BLM. The program
 

has a dual purpose—to manage the quality of the visual environment, and to reduce the visual impact of 

development activities while maintaining effectiveness in all BLM resource programs. VRM also 

identifies scenic areas that warrant protection through special management attention. The system uses 

four classes for categorizing visual resources. 

Class I —Natural ecological changes and limited management activity are allowed. Any contrasts 

created within the characteristic landscape must not attract attention. This classification is applied to 

wilderness areas, wild and scenic rivers, and other similar situations. 

8-14 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 
GLOSSARY
 

Class II —Changes in any of the basic elements (form, line, color, texture) caused by a management 

activity should not be evident in the characteristic landscape. Contrasts are seen but must not attract 

attention. 

Class III—Contrasts to the basic elements caused by a management activity are evident but should 

remain subordinate to the existing landscape. 

Class IV—Any contrast may attract attention and be a dominant feature of the landscape in terms of 

scale, but it should repeat the form, line, color, and texture of the characteristic landscape. 

water bar: A ridge made across an incline to divert water to one side. 

water quality: Refers to a set of chemical, physical, or biological characteristics that describe the 

condition of a river, stream, or lake. The quality of water determines what beneficial uses it can support. 

Different conditions or levels of water quality are required to support different beneficial uses. 

water recharge: The natural process whereby surface water enters a groundwater aquifer. 

watershed: The total land area that drains to a given watercourse or body of water. 

Waters of the U.S.: A jurisdictional term from Section 404 of the Clean Water Act referring to water 

bodies such as lakes, rivers, streams (including intermittent streams), mudflats, sandflats, wetlands, 

sloughs, prairie potholes, wet meadows, playa lakes, or natural ponds with defined bed and bank, the use, 

degradation, or destruction of which could affect interstate or foreign commerce. 

well or wellbore: The hole drilled from the surface to the gas-bearing formation, several of which may be 

developed from a single well pad. 

well pad: Relatively flat work area (surface location) that is used for drilling a well or wells and 

producing from the well once it is completed. 

wetlands: A term that varies in meaning depending on the methodology used to determine wetland 

characteristics. Typically wetlands must have plants associated with anaerobic soil conditions (no oxygen 

and saturated with water), evidence of modeling (metal deposits) or other hydric soil indicators, and the 

hydrology to allow for the location to be fully saturated at or near the soil surface for at least two weeks in 

a typical year. Wetlands can include standing water at or near the surface (typically not more than 6 feet 

deep) or saturated banks along flowing water such as riparian areas. (See also wetlands/riparian.) 

wetlands/riparian: Areas exhibiting vegetation or physical characteristics that reflect the influence of 

surface or subsurface water. These areas include lands adjacent to, or contiguous with, perennially and 

intermittently flowing rivers, streams, springs and seeps; meadows; playas; and the shores of lakes and 

reservoirs with stable water levels, among others. Excluded are ephemeral streams or washes that lack 

typical riparian vegetation. These areas can typically be identified by the plant communities that are 

present. (See also definitions for wetlands and riparian communities.) 

wind rose: Any one of a class of diagrams designed to illustrate the distribution of wind direction 

experienced at a given location over a given period of time. Wind roses may also give information 

concerning distribution of wind speed, stability, or other meteorological parameters. 

winter range: The place where migratory (and sometimes non-migratory) animals congregate during the 

winter season. 

workover: Well maintenance activities that require onsite mobilization of a drill rig to repair the well 

bore equipment (casing, tubing, rods, or pumps) or the wellhead. In some cases, a workover may involve 

development activities to improve production from the target formation. 

Wyoming Ambient Air Quality Standards (WAAQS): The allowable concentrations of air pollutants 

in the air specified by the State of Wyoming. The air quality standards are divided into primary standards 

(based on the air quality criteria and allowing an adequate margin of safety and requisite to protect the 

Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012 8-15 
GLOSSARY 

public health) and secondary standards (based on the air quality criteria and allowing an adequate margin 

of safety and requisite to protect the public welfare from any unknown or expected adverse effects of air 

pollutants). 

zone: The area between two depths in a well containing reservoir or other characteristics. 

8-16 Continental Divide-Creston Natural Gas Development Project Draft EIS  November 2012