FINAL ENVIRONMENTAL ASSESSMENT Ennis Big Sky Airport Improvements AIP # 3-30-0090-019-2017
Madison County, Montana
October 2019
TABLE OF CONTENTS ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT
TABLE OF CONTENTS
Table of Contents ...... i List of Tables ...... vii List of Figures ...... vii Acronyms ...... viii
1. BACKGROUND AND PROPOSED ACTION ...... 1-1 1.1 Background ...... 1-1 1.1.1 Airport Location ...... 1-1 1.1.2 Airport History ...... 1-1 1.1.3 Existing Facilities at EKS ...... 1-3 1.1.4 Airport Classification and Use ...... 1-7 1.1.5 14 CFR Part 77 Airspace at EKS ...... 1-7 1.1.6 Previous Airport Planning ...... 1-8 1.1.6.1 2018 Master Plan Update/Alternative Development and Evaluation Study ...... 1-8 1.2 Current and Forecasted Aviation Activity at EKS ...... 1-9 1.2.1 Types of Aircraft Using EKS ...... 1-9 1.2.2 Current Aviation Activity at EKS ...... 1-11 1.2.2.1 Current Operational Baseline ...... 1-11 1.2.3 Forecasted Annual Operations ...... 1-12 1.2.4 Critical Aircraft Determination Based on Forecasting ...... 1-13 1.3 Proposed Action ...... 1-14 1.4 Implementation of the Proposed Action ...... 1-19
2. PURPOSE AND NEED ...... 2-1 2.1 Purpose of the Proposed Action ...... 2-1 2.2 Need for the Proposed Action ...... 2-1 2.2.1 Need for Land Acquisition ...... 2-1 2.2.2 Need to Reconstruct, Extend, and Widen Runway 16/34 ...... 2-2 2.2.2.1 Need for Additional Runway Length ...... 2-2 2.2.2.2 Need for Increased Runway Width ...... 2-4 2.2.2.3 Need for Modifying Runway Grades ...... 2-4 2.2.2.4 Need for Increasing the Strength of the Runway Pavement ...... 2-5 2.2.3 Need to Relocate and Construct an Extension to the Partial Parallel Taxiway to a Full-Length Parallel Taxiway ...... 2-6 2.2.4 Need to Remove Airport Buildings ...... 2-8 2.2.5 Need to Reconstruct the South Apron ...... 2-8 2.2.6 Need to Extend Taxilane C, Construct a Portion of Taxilane D, and Construct Hangars ...... 2-8 2.2.7 Need to Relocate NAVAIDS, AWOS III/P, and Relocate/Rehabilitate Electrical Vault ...... 2-9 2.2.8 Need to Relocate Self-Service Fuel Dispensing Unit ...... 2-9 2.2.9 Need to Remove Obstructions to 14 CFR Part 77 Airspace ...... 2-10 2.2.10 Need to Amend Instrument Approach and Departure Procedures ...... 2-10 2.2.11 Need to Install Wildlife Animal Fencing ...... 2-11 2.3 Requested Federal Actions ...... 2-11
3. ALTERNATIVES CONSIDERED...... 3-1 3.1 No Action Alternative ...... 3-1
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TABLE OF CONTENTS ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT
3.2 Airport Relocation ...... 3-1 3.3 Airport Improvement Alternatives Initially Considered ...... 3-2 3.3.1 Alternative #2 – Extend Runway North Meeting FAA Runway Grade Criteria ...... 3-4 3.3.2 Alternative #4 – Rotate Runway and Extend North Meeting FAA Runway Grade Criteria ...... 3-4 3.3.3 Alternative #5 – Extend Runway to the South Meeting FAA Runway Grade Criteria ...... 3-5 3.3.4 Alternative #6 – Extend Runway to the North with Non-Standard Grade ...... 3-5 3.3.4.1 Alternative #6A – Extend Runway to the North with 1.9% Maximum Grade ..... 3-5 3.3.4.2 Alternative #6B – Extend Runway to the North with 1.5% Maximum Grade ..... 3-5 3.3.4.3 Alternative #6C – Extend Runway to the North with 1.3% Maximum Grade ...... 3-6 3.4 Alternatives Eliminated from Consideration ...... 3-6 3.5 Alternatives Carried Forward for Analysis ...... 3-9 3.5.1 No Action Alternative ...... 3-10 3.5.2 Alternative #6B – Extend Runway North with 1.5% Maximum Grade (Proposed Action) ...... 3-13
4. AFFECTED ENVIRONMENT ...... 4-1 4.1 Introduction ...... 4-1 4.2 Air Quality ...... 4-1 4.2.1 Background ...... 4-1 4.2.2 Ambient Air Quality ...... 4-2 4.3 Coastal Resources ...... 4-2 4.4 Land Use ...... 4-3 4.4.1 Existing Land Uses at and Near the Airport ...... 4-3 4.4.2 Land Use Controls on Lands Near the Airport...... 4-4 4.4.2.1 Airport Affected Area ...... 4-4 4.4.2.2 Land Use Plans ...... 4-4 4.4.2.3 Conservation Easements ...... 4-7 4.4.2.4 Land Use Compatibility ...... 4-7 4.4.2.5 Residential Through The Fence (RTTF) Access ...... 4-8 4.5 Department of Transportation Act: Section 4(f) ...... 4-8 4.6 Farmlands ...... 4-10 4.7 Biological Resources (Including Fish, Wildlife and Plants) ...... 4-11 4.7.1 Fisheries ...... 4-11 4.7.2 General Wildlife Resources ...... 4-11 4.7.3 Plants ...... 4-12 4.7.3.1 Noxious Weeds ...... 4-12 4.7.4 Migratory Birds and Eagles ...... 4-12 4.7.4.1 Migratory Birds ...... 4-12 4.7.4.2 Eagles ...... 4-13 4.7.5 Threatened, Endangered, Proposed, and Candidate Species ...... 4-13 4.7.5.1 Ute Ladies’ Tresses ...... 4-14 4.7.5.2 Canada Lynx ...... 4-14 4.7.5.3 Red Knot ...... 4-14 4.7.5.4 Wolverine ...... 4-15 4.7.5.5 Whitebark Pine ...... 4-15 4.7.5.6 Grizzly Bear ...... 4-15 4.7.6 Montana Species of Concern ...... 4-15 4.8 Hazardous Materials, Solid Waste, and Pollution Prevention ...... 4-16 4.8.1 Hazardous Materials ...... 4-16 4.8.2 Solid Waste ...... 4-16
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4.9 Historical, Architectural, Archaeological, and Cultural Resources ...... 4 - 1 7 4.9.1 Resources in the Project Area ...... 4-17 4.10 Visual Effects (Including Light Emissions) ...... 4-18 4.10.1 Light Emissions ...... 4-18 4.10.2 Visual Setting ...... 4-19 4.11 Natural Resources and Energy Supply ...... 4-19 4.12 Climate ...... 4-20 4.13 Noise and Compatible Land Use ...... 4-21 4.13.1 Noise Background and Terminology ...... 4-21 4.13.2 Noise Modeling for EKS ...... 4-21 4.13.3 Existing Noise Exposure Contours ...... 4-22 4.14 Socioeconomics, Environmental Justice, and Children’s Environmental Health and Safety Risks ...... 4-24 4.14.1 Demographic Baseline ...... 4-24 4.14.1.1 Permanent Population ...... 4-24 4.14.1.2 Seasonal Population ...... 4-25 4.14.2 Economy and Employment ...... 4-25 4.14.3 Socio-Economic Baseline ...... 4-27 4.14.4 Children’s Environmental Health and Safety Risks ...... 4-29 4.15 Water Resources ...... 4-29 4.15.1 Surface Water Resources ...... 4-29 4.15.2 Surface Water Quality ...... 4-30 4.15.3 Floodplains ...... 4-31 4.15.4 Groundwater ...... 4-32 4.15.5 Wetlands ...... 4-32 4.15.1 Wetland Identification ...... 4-33 4.15.2 Wetland Sites ...... 4-33 4.15.6 Wild and Scenic Rivers ...... 4-33
5. ENVIRONMENTAL CONSEQUENCES ...... 5-1 5.1 Introduction ...... 5-1 5.2 Air Quality ...... 5-1 5.2.1 Assessment Methodology and Impact Evaluation ...... 5-1 5.2.2 Direct and Indirect Impacts ...... 5-2 5.2.2.1 No Action Alternative ...... 5-3 5.2.2.2 Proposed Action ...... 5-4 5.2.3 Mitigation ...... 5-5 5.2.4 Conclusion ...... 5-5 5.3 Coastal Resources ...... 5-6 5.4 Land Use ...... 5-6 5.4.1 Direct and Indirect Impacts ...... 5-6 5.4.1.1 No Action Alternative ...... 5-6 5.4.1.2 Proposed Action ...... 5-6 5.4.2 Mitigation ...... 5-7 5.4.3 Conclusion ...... 5-7 5.5 Department of Transportation Act: Section 4(f) ...... 5-8 5.5.1 Direct and Indirect Impacts to Section 4(f) Properties ...... 5-8 5.5.1.1 No Action Alternative ...... 5-8 5.5.1.2 Proposed Action ...... 5-8 5.5.2 Mitigation ...... 5-9 5.5.3 Conclusion ...... 5-9
iii TABLE OF CONTENTS ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT
5.6 Farmlands ...... 5-10 5.6.1 Direct and Indirect Impacts ...... 5-10 5.6.1.1 No Action Alternative ...... 5-10 5.6.1.2 Proposed Action ...... 5-10 5.6.2 Conclusion ...... 5-11 5.7 Biological Resources (Including Fish, Wildlife and Plants) ...... 5-11 5.7.1 Direct and Indirect Impacts to Fisheries ...... 5-11 5.7.1.1 No Action Alternative ...... 5-12 5.7.1.2 Proposed Action ...... 5-12 5.7.2 Direct and Indirect Impacts to General Wildlife Resources ...... 5-12 5.7.2.1 No Action Alternative ...... 5-12 5.7.2.2 Proposed Action ...... 5-12 5.7.3 Direct and Indirect Impacts to Plants ...... 5-13 5.7.3.1 No Action Alternative ...... 5-13 5.7.3.2 Proposed Action ...... 5-13 5.7.4 Direct and Indirect Impacts to Migratory Birds and Eagles ...... 5-13 5.7.4.1 No Action Alternative ...... 5-14 5.7.4.2 Proposed Action ...... 5-14 5.7.5 Direct and Indirect Impacts to Federally-Listed Species ...... 5 - 1 4 5.7.5.1 No Action Alternative ...... 5-15 5.7.5.2 Proposed Action ...... 5-15 5.7.6 Direct and Indirect Impacts to Montana Species of Concern ...... 5-16 5.7.6.1 No Action Alternative ...... 5-16 5.7.6.2 Proposed Action ...... 5-16 5.7.7 Mitigation for Impacts to Fish, Wildlife, and Plants ...... 5-16 5.7.7.1 No Action Alternative ...... 5-16 5.7.7.2 Proposed Action ...... 5-16 5.7.8 Conclusion ...... 5-18 5.8 Hazardous Materials, Solid Waste, and Pollution Prevention ...... 5-18 5.8.1 Direct and Indirect Impacts ...... 5-19 5.8.1.1 No Action Alternative ...... 5-19 5.8.1.2 Proposed Action ...... 5-19 5.8.2 Mitigation ...... 5-20 5.8.3 Conclusion ...... 5-21 5.9 Historical, Architectural, Archaeological, and Cultural Resources ...... 5 - 2 1 5.9.1 Direct and Indirect Impacts ...... 5-21 5.9.1.1 No Action Alternative ...... 5-22 5.9.1.2 Proposed Action ...... 5-22 5.9.2 Mitigation ...... 5-23 5.9.3 Conclusion ...... 5-23 5.10 Visual Effects (Including Light Emissions) ...... 5-25 5.10.1 Direct and Indirect Impacts ...... 5-25 5.10.1.1 No Action Alternative ...... 5-25 5.10.1.2 Proposed Action ...... 5-25 5.10.2 Mitigation ...... 5-26 5.10.3 Conclusion ...... 5-26 5.11 Natural Resources and Energy Supply ...... 5-27 5.11.1 Direct and Indirect Impacts ...... 5-27 5.11.1.1 No Action Alternative ...... 5-27 5.11.1.2 Proposed Action ...... 5-27 5.11.2 Mitigation ...... 5-28
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5.11.3 Conclusion ...... 5-28 5.12 Climate ...... 5-28 5.12.1 GHG Emissions Assessment ...... 5-28 5.12.2 Mitigation ...... 5-29 5.12.3 Conclusion ...... 5-29 5.13 Noise and Compatible Land Use ...... 5-29 5.13.1 Direct and Indirect Noise Impacts ...... 5-30 5.13.1.1 No Action Alternative ...... 5-30 5.13.1.2 Proposed Action ...... 5-34 5.13.2 Mitigation ...... 5-39 5.13.3 Conclusion...... 5-39 5.14 Socioeconomics, Environmental Justice, and Children’s Environmental Health and Safety Risks ...... 5-39 5.14.1 Potential Impacts ...... 5-40 5.14.1.1 No Action Alternative ...... 5-40 5.14.1.2 Proposed Action ...... 5-40 5.14.2 Mitigation ...... 5-42 5.14.3 Conclusion ...... 5-43 5.15 Water Resources ...... 5-43 5.15.1 Direct and Indirect Impacts to Surface Waters ...... 5-43 5.15.1.1 No Action Alternative ...... 5-43 5.15.1.2 Proposed Action ...... 5-43 5.15.2 Mitigation for Impacts to Surface Waters and Water Quality ...... 5-46 5.15.3 Impacts to Floodplains ...... 5-48 5.15.4 Direct and Indirect Impacts to Groundwater ...... 5-48 5.15.4.1 No Action Alternative ...... 5-48 5.15.4.2 Proposed Action ...... 5-48 5.15.5 Mitigation for Impacts to Groundwater ...... 5-49 5.15.6 Direct and Indirect Impacts to Wetlands ...... 5-49 5.15.6.1 No Action Alternative ...... 5-49 5.15.6.2 Proposed Action ...... 5-50 5.15.7 Mitigation for Impacts to Wetlands ...... 5-53 5.15.7.1 Avoidance and Minimization ...... 5-53 5.15.7.2 Compensatory Mitigation ...... 5-53 5.15.8 Impacts to Wild and Scenic Rivers...... 5-54 5.15.9 Conclusion ...... 5-54 5.16 Cumulative Impacts ...... 5-55 5.16.1 Past, Present, and Reasonably Foreseeable Future Actions ...... 5-55 5.16.1.1 Past Actions ...... 5-55 5.16.1.2 Present Actions ...... 5-56 5.16.1.3 Reasonably Foreseeable Future Actions...... 5-57 5.16.2 Environmental Impact Categories ...... 5-58 5.16.2.1 Air Quality ...... 5-58 5.16.2.2 Coastal Resources ...... 5-59 5.16.2.3 Land Use ...... 5-59 5.16.2.4 Department of Transportation Act: Section 4(f) ...... 5-59 5.16.2.5 Farmlands ...... 5-60 5.16.2.6 Biological Resources (Including Fish, Wildlife and Plants) ...... 5-60 5.16.2.7 Hazardous Materials, Solid Waste, and Pollution Prevention ...... 5-61 5.16.2.8 Historical, Architectural, Archaeological, and Cultural Resources ...... 5-61 5.16.2.9 Visual Effects (Including Light Emissions) ...... 5-62
v TABLE OF CONTENTS ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT
5.16.2.10 Natural Resources and Energy Supply ...... 5-62 5.16.2.11 Climate ...... 5-62 5.16.2.12 Noise and Compatible Land Use ...... 5-63 5.16.2.13 Socioeconomics, Environmental Justice, and Children’s Environmental Health and Safety Risks ...... 5-63 5.16.2.14 Water Resources ...... 5-63 5.16.3 Conclusion ...... 5-64
SUMMARY OF PUBLIC INVOLVEMENT
LIST OF PREPARERS
LIST OF AGENCIES AND PERSONS CONSULTED
APPENDICES Appendix A: Relevant Correspondence and Coordination Appendix B: Airport Layout Plan Set and ALP Narrative Report (2018) Appendix C: Cultural Resource Inventories for EKS (November 2016, November 2017 and June 2019) Appendix D: EKS Biological/Wetland Resources Findings Memorandum (October 2016) Appendix E: 2018 Ennis Big Sky Master Plan Update Appendix F: Air Quality Assessment/Noise Report (March 2018) Appendix G: Asbestos and Lead Based Paint Inspection Report for EKS Hangars (December 2017) Appendix H: References
vi TABLE OF CONTENTS ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT LIST OF TABLES Table 1.1: Operational Baseline (2015) for EKS ...... 1-12 Table 1.2: Forecasted Itinerant and Local Operations at EKS ...... 1-13
Table 3.1: Alternatives Eliminated From Consideration ...... 3-6
Table 4.1: Soils Within the Project Area at Ennis Big Sky Airport ...... 4-11 Table 4.2: Historical Populations - State of Montana, Madison County, and Ennis ...... 4-25 Table 4.3: Civilian Employment by Industry (2012-2016) ...... 4-26 Table 4.4: Race and Ethnicity – U.S., State of Montana, Madison County, and Ennis ...... 4-27 Table 4.5: Selected Income Measures - State of Montana, Madison County, and Ennis ...... 4-28
Table 4.6: Miscellaneous Socio-Economic Characteristics – U.S., State of Montana, Madison County, and Ennis Area ...... 4-28
Table 5.1: Operational Emissions Inventory Results – No Action Alternative Years 2015, 2022, 2027 ...... 5-3 Table 5.2: Future Operational Emissions – Proposed Action ...... 5-4 Table 5.3: Construction Emissions Inventory Results – Proposed Action (Construction Year) ...... 5-5 Table 5.4: Estimated GHG Emissions...... 5-29 Table 5.5: Noise Impact Areas – No Action Alternative ...... 5-31 Table 5.6: Noise Impact Areas –Proposed Action ...... 5-34 Table 5.7: Water-Related Permits and Approvals Needed for Construction at EKS ...... 5-47 Table 5.8: Past Actions ...... 5-56 Table 5.9: Present Actions ...... 5-56 Table 5.10: Reasonably Foreseeable Future Actions ...... 5-57
LIST OF FIGURES Figure 1-1: Location of Ennis Big Sky Airport (EKS) ...... 1-2 Figure 1-2: Ennis Big Sky Airport Lands ...... 1-4 Figure 1-3: Ennis Big Sky Airport Layout ...... 1-5 Figure 1-4: EKS Terminal Area ...... 1-6 Figure 1-5: 14 CFR Part 77 Surfaces ...... 1-8 Figure 1-6: Aircraft Using EKS By Airport Reference Code ...... 1-10 Figure 1-7: Proposed Action at EKS ...... 1-15 Figure 1-8: Proposed Land Acquisitions at EKS ...... 1-16 Figure 1-9: Proposed 14 CFR Part 77 Airspace Obstruction Removal at EKS ...... 1-18
Figure 2-1: Centerline Profile of Runway 16/34 ...... 2-5
Figure 3-1: Potential Airport Sites in the Madison Valley ...... 3-3 Figure 3-2: No Action Alternative ...... 3-12 Figure 3-3: Alternative #6B: Extend Runway North with 1.5% Maximum Grade (Proposed Action) ...... 3-17
Figure 4-1: Existing Airport Property ...... 4-5 Figure 4-2: Airport Affected Area (AAA) for Ennis Big Sky Airport ...... 4-6 Figure 4-3: Potential Section 4(f) Lands Near the Ennis Big Sky Airport ...... 4-9 Figure 4-4: Noise Contours for the Existing Airport (2015 Baseline Conditions) ...... 4-23
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Figure 4-5: Surface Waters Near the Airport ...... 4-30 Figure 4-6: McDeed Creek and Associated Wetlands ...... 4-34
Figure 5-1: Existing Development on Tracts 4-A and 4-B ...... 5-24 Figure 5-2: Year 2022 Noise Contours – No Action Alternative ...... 5-32 Figure 5-3: Year 2027 Noise Contours – No Action Alternative ...... 5-33 Figure 5-4: Year 2022 Noise Contours – Proposed Action ...... 5-35 Figure 5-5: Year 2027 Noise Contours – Proposed Action ...... 5-36 Figure 5-6: Year 2022 Noise Contour Comparison– Proposed Action and the No Action Alternative ...... 5-37 Figure 5-7: Year 2027 Noise Contour Comparison–Proposed Action and the No Action Alternative ...... 5-38 Figure 5-8: Proposed Work in McDeed Creek ...... 5-44 Figure 5-9: Proposed Culvert Replacement Areas in Boulder Creek and Its Tributaries...... 5-45
ACRONYMS
AC Advisory Circular ACCRI Aviation Climate Change Research Initiative ACHP Advisory Council on Historic Preservation ACS American Community Survey AIA Airport Influence Areas AIP Airport Improvement Program ALP Airport Layout Plan APE Area of Potential Effect ARC Airport Reference Code AST Above-ground Storage Tank AWOS Automatic Weather Observing System
BMP Best Management Practice
CAA Clean Air Act CEQ Council on Environmental Quality CECRA Comprehensive Environmental Cleanup and Responsibility Act CERCLA Comprehensive Environmental Response, Compensation, and Liability Act CFR Code of Federal Regulations COE U.S. Army Corps of Engineers CWA Clean Water Act dB Decibel DNL Day-Night Average Sound Level DOT United States Department of Transportation
EA Environmental Assessment EDDA Environmental Due Diligence Audit EIS Environmental Impact Statement EKS Ennis Big Sky Airport EO Executive Order
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EPA United States Environmental Protection Agency EQPF Environmental Quality Protection Fund ESA Endangered Species Act
FAA Federal Aviation Administration FAR Federal Aviation Regulations FBO Fixed-Base Operator FEMA Federal Emergency Management Agency FIRM Flood Insurance Rate Map FONSI Finding of No Significant Impact FPPA Farmland Protection Policy Act
GA General Aviation GAO General Accounting Office GHG Greenhouse Gases
IBA Important Bird Area ICAO International Civil Aviation Organization
LUST Leaking Underground Storage Tank LWCF Land and Water Conservation Fund
MAAQS Montana Ambient Air Quality Standards MDEQ Montana Department of Environmental Quality MDT Montana Department of Transportation MFISH Montana Fisheries Information Database MFWP Montana Fish, Wildlife & Parks MIRL Medium Intensity Runway Lighting MNHP Montana Natural Heritage Program MPDES Montana Pollutant Discharge Elimination System MTSMP Montana Stream Mitigation Procedure
NAAQS National Ambient Air Quality Standards NAVAID Navigational Aid NEPA National Environmental Policy Act NHPA National Historic Preservation Act NPIAS National Plan of Integrated Airport Systems NPL National Priority List NRCS Natural Resource Conservation Service NRHP National Register of Historic Places
OFA Object Free Area
PAPI Precision Approach Path Indicator PARTNER Partnership for Air Transportation Noise & Emissions Reduction
RCRA Resource Conservation Recovery Act REIL Runway End Identifier Light RPZ Runway Protection Zone RSA Runway Safety Area
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SHPO State Historic Preservation Officer SPCC Spill Prevention, Control, Countermeasures SWPPP Storm Water Pollution Prevention Plan
THPO Tribal Historic Preservation Officer
USFS United States Forest Service USFWS United States Fish and Wildlife Service UST Underground Storage Tank
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ENVIRONMENTAL ASSESSMENT ENNIS BIG SKY AIRPORT MADISON COUNTY, MT
1. BACKGROUND
AND PROPOSED
ACTION
ROBERT PECCIA & ASSOCIATES
1. BACKGROUND AND PROPOSED ACTION ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT
BACKGROUND AND PROPOSED ACTION
This chapter describes Ennis Big Sky Airport and presents the planning background for the proposed projects. Madison County owns and operates the airport and is the Sponsor for the proposed improvements at the facility. This chapter also describes the Proposed Action the Sponsor is seeking to implement to safely accommodate a change in the “critical aircraft” (the most demanding aircraft type or grouping of aircraft) that make regular use of the Ennis Big Sky Airport. The Proposed Action includes acquiring additional property for the airport, extending and widening the existing runway, and making other facility improvements to better and more safely accommodate the aircraft using the facility. Further, this chapter discusses a timeline for implementation of the proposed improvements.
This Environmental Assessment (EA) was prepared to identify the potential environmental impacts associated with the Proposed Action, as well as how any identified impacts can be avoided, minimized, or mitigated. The EA was prepared pursuant to Section 102(2)(c) of the National Environmental Policy Act (NEPA) and the President’s Council on Environmental Quality (CEQ) Regulations Title 40 CFR §§ 1500-1508, the implementing regulations for NEPA, and in accordance with FAA Order 1050.1F Environmental Impacts: Policies and Procedures and FAA Order 5050.4B National Environmental Policy Act (NEPA) Implementing Instructions for Airport Actions. 1.1 Background 1.1.1 Airport Location
The Ennis Big Sky Airport (also referred to as “Airport” or by its Airport Location Identifier “EKS” in this document) is located approximately seven miles south-southeast of the Town of Ennis in the Madison River Valley of southwestern Montana. The airport property lies 1.5 miles east of Highway 287, which is the major north-south arterial through Ennis and the Madison Valley. The airport is accessed by an east-west oriented gravel access road (Airport Road/County Road 212) maintained by Madison County. A secondary north-south oriented, pulverized asphalt surfaced access road (Runway Road) provides direct access to a small gravel parking area next to the central apron and Fixed-Base Operator (FBO).
The Airport lies in Sections 19, 30, and 31 of Township 6 South, Range 1 East and Section 06 of Township 7 South, Range 1 East. Figure 1‐1 shows the Airport’s location. 1.1.2 Airport History
The Ennis Big Sky Airport is owned and operated by Madison County and has existed at its present location for more than 40 years. The Airport was originally established in the mid-1970s as the Big Sky Air Park, a private airport within the Shining Mountains land development. The Air Park was a planned development designed and constructed to provide residents with convenient access to an airport from adjoining residential areas.
After a planning process that lasted from 1986 to 1989, the FAA accepted the Ennis Big Sky Airport (formerly known as the Big Sky Air Park) into the National Plan of Integrated Airport Systems
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1. BACKGROUND AND PROPOSED ACTION ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT
Figure 1-1: Location of Ennis Big Sky Airport (EKS)
ENNIS
BEAVERHEAD-DEERLODGE NATIONAL FOREST
MOONLIGHT BASIN
BIG SKY RESORT
ENNIS BIG SKY AIRPORT
YELLOWSTONE CLUB
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1. BACKGROUND AND PROPOSED ACTION ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT
(NPIAS). Entrance into the NPIAS made the facility eligible to receive federal funding. The County subsequently received an Airport Improvement Program (AIP) grant in 1990 to design and construct improvements at the existing Ennis Big Sky Airport in order to meet FAA design standards and recommendations. The Airport has conducted numerous projects since 1992 to maintain and improve the airport.
Since 2015, Madison County used local funds to acquire lands adjacent to the Ennis Big Sky Airport as they became available to ensure land use compatibility with the airport environs and to protect design and airspace surfaces for aviation purposes. The County used local funds to acquire a parcel from the Longhorn Ranch, Tract 29-A-1, and portions of Tracts 20-A, 20-B, 13-A, and 13-B (See Figure 1‐2). The FAA had no involvement or approvals associated with the acquisitions made with local funds and therefore, there was no federal action triggering NEPA. The FAA has a federal action at the time that the FAA would approve reimbursement of land acquisition costs through the federal grant program and/or for an update to the ALP requiring FAA approval. The Sponsor is now requesting reimbursement for the land acquisitions associated with master plan improvements that require FAA ALP approval, so this prior land acquisition is being evaluated as part of the proposed action in this EA. 1.1.3 Existing Facilities at EKS
The general layout of the existing airport is shown in Figure 1‐3. The primary facilities at EKS include Runway 16/34 (a 6,601-foot long x 75-foot wide asphalt runway), and a 35-foot wide partial parallel taxiway beginning at the Runway 34 end (the northern portion of the parallel taxiway is currently closed) with two connecting taxiways. A turnaround and aircraft holding area (with no parallel taxiway connection) exists at the Runway 16 threshold.
Runway 16/34 is lighted with a radio-controlled, medium-intensity runway lighting (MIRL) system. The connecting taxiways have dual medium-intensity taxiway lights defining the entrance to the taxiways from the runway and retroreflective markers along the remaining taxiways and aprons.
The airfield has three asphalt apron areas (South, Central, and North) encompassing about 5 acres, taxilanes for hangar access, a segmented circle with lighted wind cone, Sponsor-owned AWOS III/P weather system, a rotating beacon, Sponsor-owned Precision Approach Path Indicators (PAPI’s) at both runway ends, several guidance signs, and numerous hangars and other airport buildings. Figure 1‐4 provides a detail of the terminal area at the Ennis Big Sky Airport.
Several smaller hangars front the taxilane, while two large private hangars are located along the west edge of the central apron. The FBO has been in operation at EKS since September 2012 and operates out of both large hangars. There are several buildings and structures located within the area between the central and south apron including: fuel tanks (located within a concrete containment structure), the 100LL self-serve dispensing unit, a pilot shack, an outhouse, two hangars and some smaller storage buildings, a flagpole, and the airport beacon. 24-hour self-serve 100LL fuel is provided on the taxiway, while Jet A and 100LL are available via fuel trucks during normal business hours or by previous arrangement with the FBO.
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1. BACKGROUND AND PROPOSED ACTION ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT
Figure 1-2: Ennis Big Sky Airport Lands
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Figure 1-3: Ennis Big Sky Airport Layout Runway 16 End Runway Turnaround and Aircraft Holding Area
Currently CLOSED Section of Taxiway A
Connecting Taxiway A3 Segmented Circle, Wind Cone, and AWOS III/P Partial Parallel Taxiway A
See Figure 1-4 for Detail of Connecting Taxiway A4 Terminal Area
Runway 34 End
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1. BACKGROUND AND PROPOSED ACTION ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT
Figure 1-4: EKS Terminal Area
North Apron
Taxilanes
Above Ground Storage Tanks FBO (Fuel Farm) Self-Service Fuel Hangars Dispensing Unit
SRE Building (Existing) Beacon Central Apron
New SRE/AARF Building (Under Construction 2019)
South Apron
Connecting Taxiway A4
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1. BACKGROUND AND PROPOSED ACTION ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT
There is a Snow Removal Equipment (SRE) storage building located west of the central apron and construction of a new Snow Removal Equipment and Aircraft Rescue and Firefighting (SRE/AARF) building began in 2019.
The Ennis Big Sky Airport has several designated Residential-Through-The-Fence (RTTF) access locations dating to the facility’s initial development as a residential air park. Madison County has an FAA-approved RTTF Access Agreement, which establishes the terms and conditions of use of RTTF access points for users. 1.1.4 Airport Classification and Use
The FAA’s National Plan of Integrated Airport Systems 2017‐2021 (NPIAS) identifies airports that are significant for national air transportation. The NPIAS identifies Ennis Big Sky Airport as a nonprimary General Aviation (GA) airport. Nonprimary airports are further categorized based on existing activity, geographic factors, and public interest functions such as national, regional, local, basic, and unclassified airports. The NPIAS lists EKS as a Local airport, one of 25 similarly classified GA airports in Montana. The airport primarily serves the Madison Valley and Ennis areas, but also provides nearby access into the Big Sky and Moonlight Basin resort areas.
Airports are typically designed in accordance with the Runway Design Code (RDC) designations from the FAA’s Advisory Circular (AC) 150/5300-13 Airport Design. The RDC provides information needed to determine applicable design standards. Other factors, such as aircraft haul length and Maximum Takeoff Weight (MTOW), are also considerations in the development of design standards. The RDC has three components. The first component, designated by a letter (A through E), is the Aircraft Approach Category (AAC) and relates to aircraft approach speed. The second component, designated by Roman numerals (I through VI), is the Aircraft Design Group (ADG) and relates to aircraft wingspan and tail height, whichever is most restrictive. The third component relates to the visibility minimums (distance in feet) expressed by Runway Visual Range (RVR).
EKS currently meets design standards for an RDC designation of B-II-5000. 1.1.5 14 CFR Part 77 Airspace at EKS 14 Code of Federal Regulations Part 77.19 Civil Airport Imaginary Surfaces (14 CFR Part 77) establishes a complex structure of imaginary surfaces in relation to runways at public use airports. Imaginary surfaces either slope out and up from all sides and ends of runways or are a horizontal plane or a sloping plane above the airport. The size of each imaginary surface is based on the category of each runway according to the type of instrument approach available or planned for that runway and the MTOW of the critical aircraft.
Imaginary surfaces exist primarily to prevent existing or proposed manmade objects, objects of natural growth, or terrain from extending upward into navigable airspace. According to the provisions in 14 CFR Part 77, an object is an Obstruction to Air Navigation if it is of greater height than any imaginary surface established under the regulation. There are five imaginary surfaces applied to public use airports for determining obstructions to air navigation—the primary surface, the horizontal surface, the conical surface, the transitional surface, and the approach surface. Figure 1‐5 illustrates the14 CFR Part 77 surfaces.
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The terrain east and north of the runway at EKS currently penetrates the primary, horizontal, conical, transitional, and approach surfaces. Buildings, fencing, and other airport features (the wind cone and segmented circle, AWOS equipment, and a flagpole) also penetrate one or more of the imaginary surfaces at the facility (see Figure 1‐9 at the end of this chapter). Information about airspace obstructions can also be found in the 2018 Ennis Big Sky Airport Master Plan Update (see Appendix E) and on Sheet 3 of the ALP set (see Appendix B).
Figure 1-5: 14 CFR Part 77 Surfaces
1.1.6 Airport Planning FAA guidance recommends that a Master Plan be completed or updated approximately every five years or when an airport experiences unexpected, rapid growth in activity. The most recent planning effort for the Ennis Big Sky Airport was undertaken in response to notable changes in the type of aviation activity occurring at EKS.
2018 Master Plan Update/Alternative Development and Evaluation Study The 2018 Master Plan Update and Alternative Development & Evaluation Study was initiated in 2015 and concluded in May 2018.
The airport planning effort was conducted to determine the type of airport facilities appropriate for EKS based on current and forecasted aircraft activity. The 2018 Master Plan Update (found in Appendix E of this EA) included a detailed examination of past and current aviation activity to identify trends for local versus itinerant use, annual operations, based aircraft, and the types of aircraft using the airport. The trend analysis, along with relevant socio-economic information and other published aviation forecasts, were used to establish growth rates to help forecast future aviation activity at EKS. The updated aviation forecasts for the Airport can be found in Chapter 5 of
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1. BACKGROUND AND PROPOSED ACTION ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT the 2018 Master Plan Update. The FAA’s approval of the forecast can be found in Appendix I of the 2018 Master Plan Update (see Appendix E).
Notably, the 2018 Master Plan Update documented a rapid increase in the number of Aircraft Approach Category “C” operations in recent years and forecasted an 11.78% increase in the number of annual aircraft operations at EKS in the short term. This resulted in a forecast in which Category “C” aircraft would exceed the FAA’s regular use threshold of 500 annual operations in 2018. This is significant since the critical aircraft category dictates many of the airport’s essential design standards and airspace requirements. Additionally, the critical aircraft has been forecasted to change from less than 12,500-lbs MTOW, to greater than 12,500-lbs but less than 60,000-lbs MTOW and occasional use of aircraft with up to 114,850 MTOW.
Considering the forecasted change in critical aircraft category at EKS, the 2018 Master Plan Update examined existing aviation facilities and identified design changes or improvements required to accommodate the change in critical aircraft category. Numerous development alternatives to meet the new facility requirements were evaluated and a preferred development alternative for EKS was ultimately recommended in the 2018 Master Plan Update. Other activities associated with the 2018 Master Plan Update included revising the ALP to reflect the preferred future development at EKS, public involvement opportunities, and development of an implementation plan for the recommended airport improvements. 1.2 Current and Forecasted Aviation Activity at EKS 1.2.1 Types of Aircraft Using EKS
Ennis Big Sky Airport is used for business, governmental, recreational, emergency, medical, and personal uses. The Airport is most frequently used for local and itinerant operations by small GA aircraft. However, EKS also experiences air taxi and itinerant operations by larger twin-engine aircraft and business jets.
The aircraft currently using Ennis Big Sky Airport primarily fall within Aircraft Approach Categories A, B, and C and Airplane Design Groups I and II (A-I, A-II, B-I, B-II, C-I, and C-II categories). Many of these aircraft also have MTOWs greater than 30,000 pounds but less than 100,000 pounds. Aircraft associated with the C-III category occasionally use EKS. Examples of aircraft from each major approach category are shown in Figure 1‐6.
The critical aircraft (or design aircraft) designation is important for purposes of airport geometric design and represents the most demanding aircraft type (or grouping of aircraft with similar characteristics) that makes regular use of the airport. Regular use is defined as 500 operations, including both itinerant and local operations, but excluding touch-and-go operations. Critical aircraft are designated based on their Aircraft Approach, Category (AAC), Airplane Design Group (ADG), and Taxiway Design Group (TGD). Critical aircraft can be further defined by their MTOW.
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Figure 1-6: Aircraft Using EKS By Airport Reference Code
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1.2.2 Current Aviation Activity at EKS
EKS has seen steady increases in the total number of annual operations over the past twenty years, growing from about 10,500 operations in 1997 to 12,200 operations in 2015. Although some minor year-to-year fluctuations occurred, the number of total annual aircraft operations grew at an average annual rate of 0.83% between 1997 and 2015. Over the same period, local aircraft operations and itinerant operations grew at average annual rates of 0.60% and 0.38%, respectively.
An analysis of operational data shows a notable trend of increased use by higher performance aircraft at the airport, particularly by air taxis, over the past decade. Air taxi operations at EKS have increased at a rate of more than 11% annually since 2009. This trend can be attributed to changes in facilities and services offered at EKS including: increasing the runway’s length to 6,600 feet in 2008, the addition of FBO-provided services in 2012, and the development of an instrument approach procedure in 2014. However, a healthy economy driven by recreation-based development and the associated demand for more seasonal, recreational, or occasional use housing in the area is the underlying factor contributing to the changes in the type aircraft seen at EKS.
The 2018 Master Plan Update forecasts continued growth in the number of annual operations at EKS and continued significant increases in air taxi operations over a planning period ending in 2030. The current aviation activity (operational baseline) and forecasted aviation activity at the airport are discussed in the following sections.
Current Operational Baseline
Like most non-towered airports, EKS does not have full-time equipment or personnel assigned to record the number and type of operations occurring at the facility. For this reason, the FAA’s Terminal Area Forecasts represent a consistent source of aircraft operational data at non-towered airports. The Terminal Area Forecast operational data comes from the FAA’s 5010 Airport Master Record forms, which reflect estimates from airport managers about the number of operations seen annually at each facility.
The 5010 Airport Master Record data for 2015 at the Ennis Big Sky Airport is shown in Table 1.1. This information served as the operational baseline for aviation forecasts established in the 2018 Master Plan Update.
In 2015, EKS had 12,200 total operations. Local GA operations accounted for 53% (6,500) of the operations and itinerant GA operations accounted for about 41% (5,000) of the operations. Operations by air taxis (which include B-II, C-II, and C-III aircraft) represented about 5% of all operations at the airport.
The FAA’s 5010 Airport Master Record lists 600 annual operations by air taxi in 2015. This estimate correlates well with FlightAware operational data, which showed a total of 528 operations over the 12-month period from June 2015 to June 2016. FlightAware is a privately held company that provides aviation flight tracking in over 50 countries. Air taxis are commonly operated under Instrument Flight Rules (IFR) for all flights, and are therefore, usually tracked in the data compiled by FlightAware.
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There are currently 21 aircraft based at the Ennis Big Sky Airport, which comprise the entirety of the local operations. Each based aircraft averaged approximately 310 operations (6,500 operations/21 local aircraft) or 155 flights in 2015.
Table 1.1. Operational Baseline (2015) for EKS*
ANNUAL OPERATIONS BASED AIRCRAFT
Air Carrier 0 Single Engine 20 Air Taxi/Commuter 600 Multi-Engine 1
General Aviation - Itinerant 5,000 Jet 0 General Aviation - Local 6,500
Military 100 TOTAL OPERATIONS 12,200
* Annual operations and based aircraft as established in the current FAA 5010 Airport Master Record. Available at: https://www.gcr1.com/5010WEB/ by entering airport location identifier “EKS”. 1.2.3 Forecasted Annual Operations
The number of annual operations presently occurring and projected to occur at EKS through the year 2030 were established in the 2018 Master Plan Update and a forecast was approved by the FAA on February 24, 2016. As discussed in the 2018 Master Plan Update, a variety of data and forecasting methods were considered to develop appropriate annual growth rates for local and itinerant operations, air taxi operations, and military operations to arrive at reasonable projections of future operations at the airport.
The forecasting effort in the 2018 Master Plan Update resulted in selection of annual growth rates of 0.60% for local operations, 0.38% for itinerant operations, and 3.0% for military operations at EKS.
Forecasting efforts relied on FlightAware data to help identify trends in air taxi operations at the Airport. The FlightAware data showed a 29.44% average annual growth rate for all AAC-C IFR operations over the June 2012 to June 2016 period and a 6.04% average annual growth rate for all AAC-B IFR operations over a 3-year period between June 2012 and June 2015. The AAC-C aircraft operating at EKS are most commonly air taxis. Considering this data, the 2018 Master Plan Update forecasts air taxi operations to continue increasing at an annual growth rate of 11.78% through 2020. Air taxi operations are then projected to grow at an annual rate of 2.4% through 2030, consistent with FAA’s current forecast for the turbine-powered fleet. Table 1.2 shows the number of forecasted annual operations at the airport over the 2015 to 2030 period as summarized in the 2018 Master Plan Update.
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Table 1.2: Forecasted Itinerant and Local Operations at EKS
FORECAST YEARS ESTIMATED NUMBER OF ANNUAL OPERATIONS Operational Base Year +1 Base Year Base Year Base Year Base Year Year +5 Years +10 Years +15 Years 2015* (2016) (2020) (2025) (2030) Itinerant Operations 5,000 5,019 5,096 5,193 5,293 Air Taxi/Commuter 600 671 1,047 1,179 1,327 Military 100 103 116 134 156 Local Operations 6,500 6,539 6,697 6,901 7,110 TOTAL OPERATIONS 12,200 12,332 12,956 13,407 13,886 BASED AIRCRAFT 21 22 22 23 24 * Base Total Operations as established in the 2015 FAA 5010 Airport Master Record
The analysis done for the 2018 Master Plan Update suggests the total number of annual aircraft operations may increase by nearly 14% by 2030. The forecast for EKS also indicates: Total annual local operations are projected to increase by 9.4% by 2030; Total annual itinerant operations are projected to increase by 5.9% by 2030; and Total annual air taxi/commuter operations are projected to increase by 121% by 2030. 1.2.4 Critical Aircraft Determination Based on Forecasting
The types of aircraft currently using and expected to use EKS during the forecast period were also analyzed in the 2018 Master Plan Update to identify changes in the critical aircraft category for the facility. Operations by aircraft exceeding the existing critical aircraft category of B-II, TDG-2, with a MTOW of less than 12,500 lbs at EKS were of interest.
As discussed previously in this section, FlightAware data showed a 29.44% average annual increase in IFR operations by AAC-C aircraft over the 2012-2016 period. The 2018 Master Plan Update indicates 373 operations by AAC-C aircraft at EKS in 2016. Forecasting methodologies predict the 500-annual operations threshold by AAC-C aircraft would be exceeded in 2018. This suggests AAC- C is now the appropriate Aircraft Approach Category for EKS.
The 2018 Master Plan Update examined FlightAware data to determine if changes were necessary to the Airplane Design Group (ADG) and Taxiway Design Group (TDG) at EKS. The data showed operations by aircraft in ADG-III or TDG-3 would not approach the 500-annual operations threshold during the forecast period. ADG-II and TDG-2 remain valid designations for the critical aircraft category at EKS.
Due to the increased use of the airport by heavier aircraft, the MTOW of the aircraft using EKS was also forecasted in the 2018 Master Plan Update. The analysis of FlightAware data for the 2014-2016 period indicated significant increases in the use by aircraft exceeding 60,000-lbs MTOW. However, the number of operations by aircraft in the >60,000 pounds MTOW fleet is currently low and
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1. BACKGROUND AND PROPOSED ACTION ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT forecasts show operations will not reach the regular use threshold during the forecast period. The analysis of FlightAware data revealed most of the AAC-C aircraft operating at EKS were in the “>12,500 lbs but < 60,000 lbs MTOW” fleet. With the application of anticipated annual growth rates, the number of operations by aircraft in this MTOW category is forecasted to exceed the 500 operations regular use threshold by 2019.
The 2018 Master Plan Update showed the appropriate critical design aircraft category for EKS is now C‐II‐2, >12,500 lbs but <60,000 lbs MTOW. As stated above, EKS also experiences aircraft that exceed 60,000 lbs, but that do not exceed the regular use threshold. Since the 2018 Master Plan Update, a new aircraft with a MTOW of 114,850 pounds dual wheel has been developed. These aircraft will be utilized as air taxis by operators that currently frequent EKS. Therefore, it is recommended that all pavements be designed to accommodate occasional use of aircraft up to 114,850-lbs MTOW (see Section 2.2.2.4 for a discussion of pavement strength). This change in critical design aircraft category relates directly to the recent and anticipated increase in aviation activity at the Airport. This increase is forecast to occur regardless of any improvements being made to the Airport.
The 2018 Master Plan Update also considered the need for changes to the Runway Visual Range (RVR) visibility minimums at EKS. Although an RVR designation of 5,000 feet or 4,000 feet would be applicable given the usage of the airport and the surrounding terrain, it was ultimately determined that a lower RVR was not justified or necessary. Therefore, the RVR designation of 5,000 feet for EKS remains unchanged and the forecasted ARC for the airport changes from B-II- 5000 to C‐II ‐5000.
The change in critical design aircraft category and its implications are discussed in Chapter 2. 1.3 Proposed Action The Proposed Action evaluated in this EA includes a variety of improvements at EKS that will satisfy the Purpose and Need described in Chapter 2. The Proposed Action would modify the existing airport configuration to provide a 100-foot-wide by 7,600-foot-long paved runway constructed to C-II-5000 standards and a 35-foot-wide full-length parallel taxiway (TDG-2 standards). The following elements are required to complete the Proposed Action, and the major components are shown on Figure 1‐7:
Land Acquisition (see Figure 1‐8 for proposed acquisitions) Acquire 3.17 acres of private land from two parcels adjoining the airport: . Tract 4-A (Fee acquisition of 1.96 acres of 6.42-acre parcel); and . Tract 4-B (Fee acquisition of 1.21 acres of 6.43-acre parcel). Acquire a Perpetual Easement on 17.82 acres of State of Montana land (Tract 6). Consideration of Airport Improvement Program (AIP) funding to reimburse Madison County for the use of local funds to acquire a parcel from the Longhorn Ranch, Tract 29-A-1, and portions of Tracts 20-A, 20-B, 13-A, and 13-B. Reconstruct, Extend, and Widen Runway 16/34 Reconstruct approximately 2,600 feet of Runway 16/34 to a 1.5% maximum slope and meeting vertical curve criteria.
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Figure 1-7: Proposed Action at EKS
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Figure 1-8: Proposed Land Acquisitions at EKS
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Place a 2-inch thick Hot Mix Asphalt (HMA) structural overlay on the portion of the existing runway which is not reconstructed. Construct a 999-foot-long northerly extension to Runway 16 to provide 7,600-foot-long runway with a 1.5% maximum slope. Widen Runway 16/34 to 100 feet. Grade Runway Safety Areas (RSA) to meet C-II-5000 standards and move or extend existing drainage ditches and culverts. Relocate or replace the Medium Intensity Runway Lighting (MIRL) system for Runway 16/34. Relocate the Precision Approach Path Indicators (PAPI) for Runway 16 and expand it to a four-box unit. Expand the PAPI for Runway 34 to a four-box unit. Relocate and Construct an Extension to the Partial Parallel Taxiway to a Full Length Parallel Taxiway Provide the required runway to parallel taxiway separation distance to meet C-II-5000 standards (300 feet minimum). Reconstruct the closed segment of the parallel taxiway between Taxiways A-2 and A-3 and the parallel taxiway segment connecting Taxiway A-4 and the southern edge of the central apron to restore the partial parallel taxiway to its previous length of 4,700 feet. Extend the existing partial parallel taxiway to a full-length parallel taxiway. Reconstruct Taxiways A-2 and A-4, which connect the runway to the parallel taxiway. Install Taxiway Edge Reflectors, Medium Intensity Taxiway Lighting (MITL), and guidance signs. Remove Airport Buildings Demolish two hangars located between the Central and South Aprons. Demolish or relocate Pilot’s Shack/Public Room, adjacent vault toilet, and a shed. Reconstruct the South Apron Shift apron westward to accommodate the increased width of the Runway 16/34 Object Free Area (OFA). Increase the strength of the apron pavement. Extend Taxilane C, Construct a Portion of Taxilane D, and Construct Hangars Relocate NAVAIDs, AWOS III/P, and Relocate/Rehabilitate Electrical Vault Relocate wind cone, segmented circle, and Automated Weather Observing Equipment (AWOS III/P) beyond the Runway 16/34 OFA. Relocate beacon and install beacon on a tip-down pole. Relocate vault and rehabilitate/install vault equipment. e Relocat Self‐Service Fuel Dispensing Unit Remove Obstructions to 14 CFR Part 77 Airspace (Terrain, buildings, fencing, wind cone, segmented circle, AWOS equipment, and flagpole – See Figure 1‐9) Amend Instrument Approach and Departure Procedures Install wildlife fencing around the new perimeter of the airport property
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Figure 1-9: Proposed 14 CFR Part 77 Airspace Obstruction Removal at EKS
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1.4 Implementation of the Proposed Action The primary components of the Proposed Action are projected to be completed between 2019 and 2021 pending completion of the environmental review process. Construction would be implemented in stages and under multiple FAA grants. Acquisition of east side properties and granting of the northerly perpetual easement from the State of Montana, necessary for the proposed improvements at EKS are anticipated to be completed in 2019.
Construction activities would likely begin in FY 2020 with work on the South Apron and the adjacent southern portion of the parallel Taxiway A and Runway 34 connecting Taxiway A-4. Widening and extension work would continue in FY 2020 along with other associated and miscellaneous improvements (taxilanes, runway lighting, navigational aids, full-length parallel taxiway construction). The exact timing of the individual improvements will vary based on many factors, but primarily, it will depend upon the availability of FAA funding.
Reconstruction, widening, and extension work for Runway 16/34 would result in temporary closures of the runway. Efforts would be made to keep the runway in service to the extent practicable during reconstruction work at the airport. Overall, the runway may be closed for about 90 days; however, necessary final construction closure(s) would not be determined until final design is completed.
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ENVIRONMENTAL ASSESSMENT ENNIS BIG SKY AIRPORT MADISON COUNTY, MT
2. PURPOSE AND
NEED
ROBERT PECCIA & ASSOCIATES
2. PURPOSE AND NEED ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT
PURPOSE AND NEED
This chapter describes the purpose and need for improvements at the Ennis Big Sky Airport. It presents the problem(s) to be solved (need) and describes what Madison County and the FAA are trying to achieve by implementing the Proposed Action (purpose). 2.1 Purpose of the Proposed Action
The purpose of the Proposed Action is to safely and efficiently accommodate the critical aircraft (or grouping of aircraft with similar characteristics) currently using and forecast to use EKS. To accomplish this, improvements and modifications must be made to facilities at the Airport in accordance with the FAA’s recommended design standards and guidance to address a forecasted change in the critical aircraft at the facility documented in the 2018 Master Plan Update. 2.2 Need for the Proposed Action
The Proposed Action is needed because Ennis Big Sky Airport was initially developed to accommodate frequent use by smaller and slower aircraft with shorter wingspans than the type of aircraft using the facility today. Since assuming ownership of the facility in mid-1980s, Madison County has planned and implemented numerous improvements designed to serve a critical aircraft category of B-II-5000, and aircraft less than 12,500-lbs MTOW.
As discussed in Chapter 1, Section 1.2.4, the 2018 Master Plan Update analyzed the type of aviation activity occurring at EKS and forecasts a change in critical aircraft category for the Airport. The appropriate critical design aircraft category for EKS is now C‐II‐5000, >12,500 lbs but <60,000 lbs MTOW with occasional use of aircraft up to 114,850-lbs MTOW. Although the critical aircraft has changed at EKS, the 2018 Master Plan Update concluded TDG-2 was still valid for the critical aircraft at EKS.
The needs for facility modifications at EKS are discussed in more detail below. 2.2.1 Need for Land Acquisition The existing airport boundary is adequate for B-II-5000 with <12,500-lbs aircraft design standards, but is not sufficiently sized to accommodate facility revisions to meet C-II-5000 (with greater than 12,500-lbs but less than 60,000-lbs with occasional use of aircraft up to 114,850 MTOW design standards) and meet FAA recommendations for runway length (the proposed property acquisitions are shown on Figure 1‐8 in Chapter 1). Land acquisitions necessary to meet standards include:
Fee acquisition of tracts from two parcels of land adjoining the east perimeter of the Airport (Tracts 4-A and 4-B), which are needed to accommodate the required Object Free Area (OFA) for the Airport to meet C-II-5000 design standards.
A perpetual easement from the State of Montana (Tract 6), which is necessary on adjacent land to the north to accommodate the required OFA, enable the recommended northerly extension of Runway 16, and provide additional runway protection for Runway 16/34.
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The proposed fee acquisitions (totaling 3.17 acres) occur within the Shining Mountains Air Park of the Mustang Ranches Subdivision in Section 31 of Township 6 South, Range 1 East. Tract 4-A consists of vacant and unimproved rural residential subdivision land. Tract 4-B is an improved tract with a residence and out buildings. (The residence and out buildings on the property are not within the proposed 1.21-acre acquisition area on Tract 4-B.)
Tract 6 is located in Section 30 of Township 6 South, Range 1 East, and includes State of Montana Trust Land adjoining an existing perpetual easement on 59.66 acres of land obtained by the County for a previous runway extension and approach protection for Runway 16 (see Figure 1‐2 for locations of Tracts 2 and 3 that make up the existing perpetual easement). Tract 6 is unimproved land currently used for livestock grazing. A perpetual easement is proposed on Tract 6 because Madison County already has an easement on Tracts 2 and 3 and the same large parcel of State land would be affected.
As explained in Chapter 1, Section 1.1.2 and shown on Figure 1‐2, Madison County used local funds to acquire lands adjacent to the Ennis Big Sky Airport and would like consideration for reimbursement for the acquisition of parcels of property that lie on the west side of the Airport. These parcels are needed to accommodate the required OFA for the Airport to meet C-II-5000 design standards. 2.2.2 Need to Reconstruct, Extend, and Widen Runway 16/34
The Proposed Action would reconstruct and widen Runway 16/34 along its present orientation (alignment) to adequately accommodate the most demanding aircraft now using and forecast to use EKS—aircraft in the C-II-5000, TDG-2, >12,500 lbs but <60,000 lbs MTOW category according to FAA AC 150/5300-13A. Based on the analysis performed for the 2018 Master Plan Update, a runway 7,600-feet-long is recommended to accommodate aircraft in this category.
In conjunction with the proposed modifications to Runway 16/34, revisions must also be made to the Medium Intensity Runway Lighting (MIRL) system and navigational aids for the runway. One or both existing Precision Approach Path Indicators (PAPIs) for Runway 16/34 must be relocated due to the proposed runway widening and extension. The Runway 16 PAPI equipment would need to be relocated based on the future threshold location. The Runway 34 PAPI equipment may be able to remain in place, although adjustments may be necessary based on shoulder grading and any runway profile changes. Both “two-box” PAPI (L-881) units would need to be expanded to “four- box” units (L-880) to accommodate for jet aircraft operations in accordance with FAA AC 150/5340-30.
Need for Additional Runway Length
Due to the large number of variables associated with aircraft performance, operating conditions and site characteristics at airports, the FAA has not established specific standards for runway length. However, the FAA’s AC 150/5325-4B, Runway Length Requirements for Airport Design provides guidance and a multi-step procedure for determining recommended runway lengths. The AC notes various factors that govern the suitability of available runway length including: the airport’s elevation, temperature, wind velocity, aircraft operating weights, the performance
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2. PURPOSE AND NEED ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT characteristics of the critical aircraft regularly using the facility, runway surface condition, effective runway gradient (slope), and airspace obstructions.
Section 6 of the 2018 Master Plan Update assessed facility needs at EKS and determined the existing runway length of 6,601 feet at EKS was inadequate based on several considerations. The 2018 Master Plan Update considered historical operations data and aviation forecasts to identify the critical aircraft at EKS and establish future airfield requirements at EKS. Section 6.B. of the 2018 Master Plan Update discusses the inputs and conditions used to determine the recommended runway length for the Runway 16/34 at EKS considering the methodology outlined in AC 150/5325-4B. Key inputs or conditions for the runway length determination included:
Mean daily maximum temperature of the hottest month of the year of 83.2 F; Airport elevation of 5,423 feet; A critical aircraft (or grouping of aircraft) with >12,500-lbs but < 60,000-lbs MTOW with occasional use of aircraft up to 114,850 MTOW; and Accommodating 75% of the aircraft in the turbojet-powered fleet at 60% useful load.
Based on the methodology from the AC and applying appropriate adjustments for effective runway gradient and wet or slippery runway surface conditions, a runway length of 7,600 feet was recommended at EKS. The 2018 Master Plan Update suggests an “ultimate” runway length of 8,700 feet may be desirable by the end of a 20-year planning horizon; however, a runway of that length would need to be justified through additional planning if aviation activity and facility use changes.
Runway length needs were also verified by examining the performance charts for representative aircraft using the Airport. While there is not a single distinct critical aircraft for EKS, the five most common aircraft with MTOW >12,500-lbs currently using the Airport were identified. These aircraft include:
Cessna Citation 560 Excel / XLS Beechcraft Hawker 400 Cessna Citation 680 Sovereign Dassault Falcon 2000 Cessna 750 X / Ten
The review of performance characteristics for these aircraft shows a 7,600-foot-long runway would generally be sufficient under 60% useful loading conditions. However, surface conditions on the runway or air temperatures could affect performance for some aircraft operating at 60% useful load on a 7,600-foot-long runway. Reducing aircraft loadings or varying the timing of operations should allow these aircraft to safely operate with a 7,600-foot-long runway at EKS. The potential costs of initially constructing a runway longer than 7,600 feet to allow a relatively small number of aircraft to operate at a minimum of 60% useful loadings, under all temperatures and runway surface conditions, cannot be justified. Figure 1‐7 in Chapter 1 shows the proposed extension to Runway 16.
The proposed extension of Runway 16/34 to a length of 7,600 feet would require other associated improvements including: acquiring additional land (Tract 6); clearing vegetation and excavation, grading, and paving of the new runway surface; relocating the threshold for Runway 16; relocating and/or replacing the Runway 16 PAPI; relocating and installing new runway and taxiway lighting;
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2. PURPOSE AND NEED ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT modifying signing and striping for the runway; and amending instrument approach and departure procedures.
Need for Increased Runway Width
According to FAA AC 150/5300-13A, the width of a runway is determined by its RDC. The current RDC for Runway 16/34 at EKS is B-II-5000 and the existing runway is 75-feet-wide. The re- designation of Runway 16/34 at EKS to an RDC of C-II-5000 (not lower than 1-mile visibility) requires a runway width of 100 feet with 10-foot-wide shoulders per Table A7-8 Runway Design Standards Matrix, C/D/E – II.
Need for Modifying Runway Grades
The current runway meets the FAA’s requirements for gradient (slope) for Aircraft Approach Category (AAC) B. However, the runway’s grade needs to be modified to comply with the FAA’s design requirements for AAC C listed in Paragraph 313 b of AC 150/5300-13A. Gradient or slope is expressed as a percentage, by dividing the elevation change by the distance or length. FAA design standards for this Aircraft Approach Category set the maximum longitudinal grade on the runway at 1.5% and limit grades to 0.80% in the first and last quarter (or first and last 2,500 feet) of the runway’s length, whichever is less. With respect to EKS, this means no portion of Runway 16/34 can have grades exceeding 1.5% slope and the runway grade over the first 1,900 feet of extended Runway 16 cannot exceed 0.80% slope. The northernmost 1,900 feet of the runway (Runway 16 end) has an existing grade of 1.92%, which meets runway grade requirements for AAC B, but not AAC C.
Reconstruction to meet the FAA’s design standards for runway grade or the agency’s approval of one or more Modifications of Standards (MOS) applicable to airport design is necessary to address the longitudinal grade deficiencies associated with the existing runway in order to meet requirements for AAC C at EKS. According to FAA Order 5300.1G Modifications to Agency Airport Design, Construction, and Equipment Standards (September 29, 2017), “any deviation from, or addition to standards, applicable to airport design, material, and construction standards, or equipment projects resulting in an acceptable level of safety, useful life, lower costs, greater efficiency, or the need to accommodate an unusual local condition on a specific project through approval on a case-by-case basis.”
The FAA has indicated it will not grant MOS approvals for variances from the 1.5% maximum grade requirement or vertical curve criteria for the Runway 16/34 at EKS. However, the agency has granted MOS approval for the requirement to meet the 0.80% longitudinal gradient for the north end of the Runway 16 (including the proposed 1,000-foot-long northerly extension of the runway). The MOS, approved on March 13, 2018, for EKS allows for a constant grade of 1.5% within the first quarter of the extended length for Runway 16. Nine hundred feet of the existing runway will be reconstructed at a 1.5% slope, and the 1,000-foot-long runway extension will be constructed at a 1.5% slope, as well. Runway 34 would maintain a maximum 0.80% longitudinal grade within the first quarter of the runway length, consistent with FAA design standards. Figure 2‐1 shows the proposed profile grade of Runway 16/34 and the area affected by the MOS.
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The existing runway also has areas where the grade changes exceed the FAA’s allowable vertical curve criteria. Vertical curves are used to provide a gradual change between two adjacent runway segments with different grades. At EKS, the runway has three areas where grade changes occur over too short of a distance. Reconstruction of these runway sections is needed to provide vertical curves consistent with the FAA’s design standard.
Figure 2-1: Centerline Profile of Runway 16/34
According to FAA Order 5300/1G, all MOS associated with design standards must be reviewed whenever there is an opportunity to meet standards, when situations change, or if a MOS is no longer required. Additionally, all MOS associated with design standards expire no later than 5 years from the approved date (March 13, 2018 in this instance). The airport must re-submit the MOS for review and approval: 1.) no more than every 5-years from the date of approval, 2.) if extension is requested, 3.) when there is an opportunity to meet standards or if the MOS is no longer required (prior to a major rehabilitation effort for example), 4.) if any conditions originally justifying the modification change, or 5.) if the FAA deems re-evaluation is in the public’s best interest.
Therefore, Runway 16/34 would be reconstructed to meet FAA design standards for maximum grade and vertical curve requirements, with exception to the Runway 16 end being reconstructed / constructed at a maximum grade of 1.5% in accordance with the approved MOS. The MOS is not granted in perpetuity and must be reevaluated within any future extension or proposed major rehabilitation effort.
Need for Increasing the Strength of the Runway Pavement
Airport pavements are designed and constructed to provide adequate support for the loads imposed by airplanes and to produce a firm, stable, smooth, skid resistant, year-round, all-weather surface. The pavement must also possess sufficient inherent stability to withstand the adverse effects of traffic, weather, and other deteriorating influences.
The critical aircraft for EKS is identified in the category for >12,500 lbs but <60,000 lbs MTOW.
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However, in accordance with FAA AC 150/5320-6, airport pavements must be designed to accommodate occasional use by heavier aircraft in order to ensure pavement damage does not occur with occasional use and the life expectancy of the pavements is met. Some pavements, like taxilanes, may be designed to accommodate only the aircraft (and support vehicular equipment such as snow plows) that will traverse the pavement.
The landing gear type and configuration dictates how an aircraft’s weight is distributed to the pavement and how the pavement responds to airplane loadings. The existing runway pavement was reconstructed/constructed in 2008 and was designed to a 30,000 pounds single and 47,000 pounds dual wheel gear configuration, consistent with FAA guidance for pavement design and the forecasted aircraft fleet mix at EKS at the time.
FAARFIELD, a computer program developed by the FAA to assist in the design of airport pavements, was used to analyze pavement thickness and strength requirements for the 2018 Master Plan Update. The forecasted aircraft fleet mix and growth in operations at the Airport were key inputs to the FAARFIELD program. It is important to note the computer program does not rely on single critical aircraft for the analysis but instead, focuses on those aircraft in the fleet mix that could potentially contribute the greatest amount of damage to the pavement. At EKS, most of the larger and heavy aircraft were identified from the evaluation of FlightAware data for the 2012 through 2016 period. Appendix J in the 2018 Master Plan Update lists the aircraft within the forecasted fleet mix (and their gross weights) used to help determine pavement strength needs at EKS.
Considering the forecasted trend of increased use by larger and heavier aircraft and the aircraft fleet using and anticipated to use EKS, the 2018 Master Plan Update concluded increasing the strength of the runway pavement was warranted. The 2018 Master Plan Update recommended increasing the strength of the runway pavement to 66,000 pounds single and 85,000 pounds (for dual wheel gear configuration aircraft) through reconstruction or structural overlays. However, since the 2018 Master Plan Update a new aircraft with a MTOW of 114,850 pounds dual wheel has been developed. These aircraft will be utilized as air taxis by operators that currently frequent EKS. It is recommended that all pavements be designed to accommodate occasional use by aircraft up to 114,850-lbs MTOW. The Proposed Action would implement the recommendation for increased pavement strength to help assure that damage does not occur when aircraft exceeding 60,000-lbs MTOW use the runway at EKS. 2.2.3 Need to Relocate and Construct an Extension to the Partial Parallel Taxiway to a Full-Length Parallel Taxiway
The 2018 Master Plan Update recommended the development of a full-length parallel taxiway at EKS to improve overall airport operational efficiency and flexibility and help ensure efficient use of the runway at the airport. Reconstructing the partial parallel taxiway and extending it to the full- length of the new runway would benefit the operation and safety of the Airport by eliminating the need for aircraft to use the runway for taxiing to and from landside facilities and the end of Runway 16. Use of the runway as a taxiway offers the potential for aircraft incursion incidents and increases the time that aircraft occupy the runway. The operational flexibility of EKS is currently hindered by the need to use the runway as a taxiway to access the dead end(s) of the runway.
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The Ennis Big Sky Airport currently has a 2,485-foot-long by 35-foot-wide partial parallel taxiway (identified as Taxiway A on the ALP) extending from Taxiway A-4 at the end of Runway 34 to Taxiway A-3 (the taxiway connecting the runway and parallel taxiway located about 600 feet north of the North Apron). A 2,215-foot-long portion of the partial parallel taxiway between Taxiways A- 2 and A-3 was abandoned during a terminal area improvement project in 2016 when the parallel taxiway south of Taxiway A-3 was rebuilt at an increased runway to taxiway separation distance.1
Reconstructing and shifting the “abandoned” parallel taxiway segment is necessary to restore the partial parallel taxiway to its previous length of 4,700 feet between connecting Taxiways A-2 and A- 4. This reconstructed segment of Taxiway A must also be built to the same runway to taxiway separation distance and width as provided by the 2016 project, which would meet the FAA’s minimum lateral separation standard of 300 feet for a C-II-5000 facility. Taxiway A would also be extended to provide a full-length parallel taxiway. The strength of the Taxiway A pavement would be increased to approximately 114,850-lbs MTOW (dual wheel gear configuration aircraft). Figure 1‐7 in Chapter 1 shows the proposed full-length parallel taxiway.
Reconstruction of Taxiways A-2 and A-4 connecting the runway and parallel taxiway would also be necessary. The taxiway reconstruction work would include the provision of pavement fillets, which are widened areas of pavement at the outer edges of intersections. Pavement fillets are designed to allow all aircraft to maneuver safely through turns, while keeping their nose gear on centerline (cockpit over centerline).
Taxiway geometry and dimensions are determined with both the Airplane Design Group (ADG) and the Taxiway Design Group (TDG) in accordance with AC 150/5300-13A (Change 1). The ADG, which is based on a plane’s wingspan and tail height, is used for the taxiway clearance and separation requirements, while the TDG controls the pavement width and taxiway edge safety margin.
Taxiway Design Groups are based on a combination of an airplane’s main gear width and the cockpit to main gear distance, both of which influence the steering characteristics. The existing partial parallel taxiway (as well as the abandoned portion) is 35-feet wide and accommodates only ADG-II/TDG-2 aircraft. The recommendations in the 2018 Master Plan Update indicate the parallel taxiway should be designed to continue to serve ADG-II/TDG-2 aircraft.
EKS currently has L-853 taxiway reflectors in lieu of taxiway lighting, with dual taxiway lights delineating taxiway-runway intersections. This is considered non-standard in accordance with AC 150/5340-30H, which only allows taxiway reflectors to supplement taxiway lighting. While this taxiway reflector configuration is standard for many general aviation airports in Montana, the installation of a Medium Intensity Taxiway Lighting (MITL) would be included as part of the
1 The 2016 project at EKS was undertaken in response to safety concerns caused by heavier than designed aircraft using the pavement and causing failures on the North Apron and adjoining Taxiway A-3. There was agreement that the apron and taxiway pavements needed reconstruction as soon as possible. The Master Plan Update was underway and it was apparent from forecasting efforts that EKS would likely change from a B-II to a C-II facility. For this reason, a decision was made at the time to reconstruct Taxiway A-3 in a location that would be within design standards for either a B-II or C-II facility.
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Proposed Action to meet the guidance in AC 150/5340-30H. 2.2.4 Need to Remove Airport Buildings
Several existing buildings located between the Central and South Aprons must be removed to accommodate future development to C-II-5000 design standards at EKS. The pilot’s shack, vault toilet, and a hangar are within the future Runway Object Free Area (OFA) and must be removed consistent with FAA AC 150/5300-13A. The AC indicates “objects non-essential for air navigation or aircraft ground maneuvering purposes are not to be placed in the OFA.” A second hangar and a shed encroach upon or are within the future Building Restriction Line (BRL) for Runway 16/34. These structures are also built in areas depicted on the ALP for future and ultimate apron expansions. 2.2.5 Need to Reconstruct the South Apron
Currently, the Ennis Big Sky Airport has approximately 143,200 square feet of available apron space allocated between the South, Central, and North Aprons. The available apron space at EKS is generally adequate for current and forecasted activity levels. However, the increased runway to taxiway separation and OFA standards associated with upgrading the Airport from RDC B-II-5000 to C-II-5000 would substantially reduce the available space for aircraft parking and maneuvering on the South Apron. For this reason, the South Apron needs to be shifted westward to accommodate for the increased Runway 16/34 OFA width for a C-II-5000 configuration and maintain a similarly-sized apron area. Figure 1‐7 in Chapter 1 shows planned modifications to the South Apron and proposed new taxiway centerline and OFA. More detailed drawings of the South Apron area can be found on the Terminal Area Plan (Sheet 7) of the Airport Layout Plan Set in Appendix B of this EA.
The South Apron pavement, designed only to meet a 12,500 pounds single or dual wheel gear configuration, is in poor condition. The South Apron pavement was originally constructed in 1992 and has only seen preventative pavement maintenance activities since that time. The North Apron and an associated expansion area were constructed in 2016 with pavement meeting the design strength to accommodate aircraft of 66,000 pounds single, 85,000 pounds dual, and 144,000 pounds dual-tandem wheel gear configurations. Given the increased use by heavier aircraft, the pavement for the South Apron needs to be reconstructed and designed to accommodate 114,850- lbs MTOW dual wheel gear configuration aircraft. The South Apron would be constructed with small aircraft tie-down positions, typically serving smaller aircraft. However, it would also serve as an “overflow” apron during peak seasons and must be cable of handling the aircraft regularly utilizing the Airport without incurring pavement damage. 2.2.6 Need to Extend Taxilane C, Construct a Portion of Taxilane D, and Construct Hangars
The existing hangar access taxilane (Taxilane C) is 25-feet wide and accommodates only small A/B- I, TDG-1 aircraft. The recommendations in the 2018 Master Plan Update indicate the main taxiways for EKS should be developed to accommodate TDG-2 aircraft and the hangar taxiways/taxilanes
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2. PURPOSE AND NEED ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT should be developed to serve both TDG-1 and TDG-2 aircraft. While TDG-1 taxiways/taxilanes require a 25-foot pavement width, taxiways/taxilanes for TDG-2 aircraft require a 35-foot pavement width. Any reconstruction or extension of Taxilane C or new taxilane construction at EKS must meet all FAA dimensional requirements, for which the type of aircraft the taxilane is intended to serve (TDG-1, TDG-2, etc.). The pavement strength for taxilanes must also be sufficient to accommodate the type of aircraft to be served.
Extending Taxilane C as proposed would provide access to a portion of the airport property where additional hangars can be developed for TDG-1 aircraft. In addition, extending Taxilane C would facilitate access to the SRE and ARFF storage building at the Airport. Hangar construction along Taxilane C would be completed by private parties with no federal funding participation.
The construction of a portion of Taxilane D is proposed for the area west of Taxilane C. Construction of this taxilane would provide access to an area where hangars for TDG-2 aircraft can be developed. As with Taxilane C, hangar construction along Taxilane D would be completed by private parties with no federal funding participation.
Figure 1‐7 in Chapter 1 shows proposed taxilane modifications at EKS. More detailed drawings of the taxilane and hangar area can be found on the Terminal Area Plan (Sheet 7) of the Airport Layout Plan Set in Appendix B of this EA. 2.2.7 Need to Relocate NAVAIDS, AWOS III/P, and Relocate/Rehabilitate Electrical Vault The Airport’s existing wind cone and segmented circle are located just east of mid-field. The automated weather observing system equipment (AWOS III/P) is located within the segmented circle. These NAVAIDs and AWOS equipment lie within the Runway 16/34 OFA for a C-II-5000 design configuration at the Airport and must be relocated outside the new OFA.
The existing rotating beacon would be moved further west to its “ultimate” location to accommodate development of the South Apron and the “ultimate” terminal area. The existing beacon would be relocated onto a tip-down pole.
In addition, the electrical vault will be relocated adjacent to the new beacon location. Rehabilitation or replacement of the electrical vault equipment for the MIRL and MITL is necessary because the equipment is outdated and not adequately sized to handle the proposed expansions of the runway and taxiway lighting systems and NAVAID improvements. This action would include installation of new constant current regulators, transformers, booster transformers, radio control equipment, lighting control panels, and associated modifications. 2.2.8 Need to Relocate Self-Service Fuel Dispensing Unit
The existing self-serve avgas fuel (100LL) dispensing unit located east of the existing above ground storage tanks (ASTs) and adjoins the Central Apron. The dispensing unit requires relocation to accommodate the proposed improvements and ensure the fueling equipment does not encroach on the Runway OFA and Taxiway Safety Area. The self-service fuel dispensing unit would be moved to
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2. PURPOSE AND NEED ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT a location adjoining the north side of the existing AST farm. The FBO would complete relocation in accordance with their Spill Prevention Countermeasure and Containment (SPCC) plan and all applicable code and regulations. The FBO would be required to update their SPCC plan accordingly. All work associated with the fuel dispensing unit relocation would be completed by the private party with no Federal funding participation. 2.2.9 Need to Remove Obstructions to 14 CFR Part 77 Airspace
The existing airport currently has obstructions in all the airspace surfaces. Most of the obstructions are structures and trees situated on rising terrain, as well as the terrain itself within the horizontal and conical surfaces. The transitional surface penetrations include the wind cone, segmented circle, AWOS equipment, a fence line, and terrain. During the 2008 construction project, terrain penetrations were cleared for the 20:1 visual approach surface to Runway 16 in place at the time. Since both ends of Runway 16/34 now have non-precision GPS procedures with 34:1 approach surfaces, terrain and fences penetrate both approach surfaces.
The airspace surfaces for “Other than Utility” runways (runways designed for >12,500-lbs MTOW aircraft), with not lower than one-mile visibility minimums at EKS, would not change the relative size of the associated 14 CFR Part 77 surfaces. However, extending the runway northward, as proposed, elongates the surfaces, creating new terrain penetrations in the primary, transitional, and approach surfaces. The imaginary surfaces would also shift eastward due to the runway centerline shift.
Airspace penetrations would need to be clearly identified during design and resolved to the extent practicable through surface grading or obstruction removal. Penetrations to the horizontal and conical surface caused by the rising topography east of the Airport cannot be readily resolved because it is not feasible to clear, excavate and grade large extents of foothill and mountainous terrain (representing 2,600-feet plus of vertical penetrations) on lands that include the Beaverhead-Deerlodge National Forest (See Figure 1‐9 in Chapter 1). 2.2.10 Need to Amend Instrument Approach and Departure Procedures Extending Runway 16 to the north requires new approach/departure procedure development because the runway threshold and touchdown zone will be changed. Widening of the runway (proposed to occur all to the east side) also requires a new Runway 34 approach procedure since the runway threshold would shift 12.5 feet to the east. The FAA completes these amendments with survey and aerial imagery information provided by Madison County. It is anticipated that the minimums would be very close to the existing procedures, as the terrain is similar north of the proposed Runway 16 threshold and the shift in the runway centerline to the east would have minimal impacts for obstacle clearance.
All existing procedures would require amendment, including:
RNAV (GPS) RWY 16 RNAV (GPS) RWY 34 ENNIS ONE (OBSTACLE) (RNAV) - Departure
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2.2.11 Need to Install Wildlife Animal Fencing
Installation of a 9-foot high wildlife fence around the perimeter of the entire Airport property would be accomplished after land acquisition has been completed and segments of the existing fence have been removed from the future OFA. 2.3 Requested Federal Actions
Madison County is requesting the following federal actions from the FAA:
Unconditional Approval of the Proposed Action as shown on the Draft ALP. A copy of the Draft ALP set can be found in Appendix B.
Determination that environmental analysis prerequisites associated with any future Airport Improvement Program (AIP) funding application have been fulfilled pursuant to 49 U.S.C § 47101.
Amendments to existing instrument approach and departure procedures at EKS. The Airport currently has RNAV GPS approaches for each end of the existing runway and an RNAV departure procedure. These procedures would need to be amended based on the 1,000-foot-long northerly extension of the runway and the change in runway centerline location (12.5-foot lateral shift eastward) associated with the Proposed Action.
Consideration of Airport Improvement Program (AIP) funding to reimburse Madison County for the use of local funds to acquire a parcel from the Longhorn Ranch, Tract 29-A-1, and portions of Tracts 20-A, 20-B, 13-A, and 13-B.
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ENVIRONMENTAL ASSESSMENT ENNIS BIG SKY AIRPORT MADISON COUNTY, MT
3. ALTERNATIVES
CONSIDERED
ROBERT PECCIA & ASSOCIATES
3. ALTERNATIVES CONSIDERED ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT
ALTERNATIVES CONSIDERED
This Chapter of the EA discusses the alternatives considered for the proposed improvements at EKS. These alternatives generally include taking no action to resolve the deficiencies, developing replacement aviation facilities at another site, and modifying the configuration and improving the existing airport facilities based on several development concepts.
The Madison County Commissioners and the Madison County Airport Board considered a full range of alternatives to address the aviation deficiencies and needs at EKS described in Chapter 2. This chapter identifies the alternative(s) that meet the purpose and need for making improvements at EKS, discuss alternatives eliminated from consideration, and identify the Proposed Action.
The alternatives initially considered at EKS are described on the following pages. 3.1 No Action Alternative This alternative involves the continued use of the existing Ennis Big Sky Airport. No improvements or facilities would be added and only maintenance and existing pavement rehabilitation activities would be completed to ensure the continued operation of the Airport. Aviation activity is expected to continue to increase at the same rate as discussed in Chapter 1 even if nothing is done to improve the facility.
EKS has seen significant increases in use by larger and heavier aircraft in recent years and this trend is expected to continue in the foreseeable future regardless of improvements at the airport. Existing use has contributed to areas of failed pavements (i.e. rutting, alligator cracking, depressions, etc.) which impacts the safe operation of the facility and requires pavement repairs. Additionally, the increased larger traffic causes congestion within the aprons and taxiways during peak season, which leads to safety hazards with aircraft parked within taxiway and runway OFA’s. These conditions would continue if no action were taken.
The No Action Alternative (identified as Alternative #1 in the 2018 Master Plan Update), would not change the configuration of EKS from its present condition. The Airport is currently configured to serve a critical aircraft RDC category of B-II-5000, with aircraft <12,500 lbs MTOW. As documented in the 2018 Master Plan Update and discussed in previous chapters of the EA, the appropriate critical aircraft category for EKS future improvements is C-II-5000, with aircraft >12,500 lbs but less than 60,000 lbs MTOW with occasional use of aircraft up to 114,850 MTOW. As a result, the existing facility does not meet applicable standards for runway design (runway width, runway surface gradient, runway separation, etc.). Not upgrading the existing airport to meet standards established by the FAA for the critical aircraft at EKS could also jeopardize the Sponsor’s eligibility for future federal funding to maintain the Airport. 3.2 Airport Relocation Development of a new airport would require an estimated 200 acres or more of land in relatively level terrain to accommodate facility development and provide adequate area for OFAs and RPZs. Other considerations such as compatible land uses, environmental limitations, access to utilities, proximity to populated areas, unobstructed approach and departure paths, and convenient ground
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3. ALTERNATIVES CONSIDERED ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT access, are all necessary for a viable airport site.
Establishing a new airport elsewhere in the Madison Valley to replace the existing facility has received consideration during past planning efforts. Developing an airport in the Ennis area was examined in 1971 during the development of a County Aviation Plan, which considered five potential airport sites. The concept was again considered during airport planning projects in 1980 and 1986 and discussed in the EA completed for improvements at the Ennis Big Sky Airport in 1999.
The 2018 Master Plan Update also revisited the topic of airport relocation (identified as Alternative #3 in the 2018 Master Plan Update) to evaluate whether a new location may better accommodate the critical aircraft than the existing facility. Alternative airport sites in the northern portion of the Madison Valley were not researched in depth; however, the 2018 Master Plan Update concluded few locations appear suitable for airport construction due to the airspace limitations caused by the area’s terrain and potential environmental impacts resulting from airport development.
The 2018 Master Plan Update identified several potential airport sites in the Madison Valley south of the Ennis Big Sky Airport (see Figure 3‐1). As the figure shows, large areas of mountainous land in the Beaverhead-Deerlodge National Forest or agricultural and grazing lands under conservation easements exist in the Madison Valley. The identified potential airport sites are located 4 to 12 road miles farther from Ennis than the existing airport. 3.3 Airport Improvement Alternatives Initially Considered
The 2018 Master Plan Update included a detailed evaluation of existing facilities at the Airport and defined the type of aviation facilities and improvements necessary at EKS to accommodate the forecasted activity. As discussed in Chapter 1 and Chapter 2, the 2018 Master Plan Update forecasts a change in critical aircraft category from B-II-5000, with aircraft <12,500 lbs MTOW, to C-II-5000, with aircraft >12,500 lbs but <60,000 lbs MTOW with occasional use of aircraft up to 114,850 MTOW, and recommends the need for facility modifications at EKS to meet the FAA's design standards and guidelines for the critical aircraft.
The 2018 Master Plan Update critically reviewed the existing aviation facilities at EKS relative to the FAA's design standards and identified needed modifications to airside pavements (principally, the runway and parallel taxiway) and their associated object free areas, the runway protection zones, and the associated imaginary airspace surfaces. Desirable improvements to taxilanes and hangars, the terminal area, aprons, vehicle access and parking, and other airport facilities were also considered.
The 2018 Master Plan Update has a long-term planning horizon and highlights facility changes at EKS that may be needed over the next 20 years based on forecasted activity trends. However, emphasis was given to addressing the more immediate need to modify EKS to accommodate the newly identified critical aircraft category and meet the design standards. Improvement alternatives considered in the 2018 Master Plan Update were established to meet this foreseeable “future” condition but not preclude development to satisfy ultimate facility needs at EKS.
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3. ALTERNATIVES CONSIDERED ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT
Figure 3-1: Potential Airport Sites in the Madison Valley
Existing Airport
Source: 2018 Master Plan Update
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3. ALTERNATIVES CONSIDERED ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT
The 2018 Master Plan Update then identified and evaluated the following improvement alternatives at the existing airport location:
Alternative #2 – Extend Runway to the North Meeting FAA Runway Grade Criteria; Alternative #4 – Rotate Runway and Extend North Meeting FAA Runway Grade Criteria; Alternative #5 – Extend Runway to the South Meeting FAA Runway Grade Criteria; and Alternative #6 – Extend Runway to the North with Non-Standard Runway Grade.
Common elements of these airport improvement alternatives include:
Extending the existing runway from 6,601 feet to 7,600 feet in length; Widening Runway 16/34 from 75 feet to 100 feet; Strengthening the runway and other airport pavements; Providing a full-length parallel taxiway and increasing the separation distance from the runway to the parallel taxiway to at least 300 feet; Providing an aircraft parking separation distance of 400 feet from the new runway centerline; Meeting FAA dimensional requirements associated with development of a C-II-5000 runway (Runway Protection Zones, Object Free Areas, and Threshold Siting Surfaces); Clearing imaginary airspace surface in accordance with 14 CFR Part 77 for an “other than utility runway” (>12,500-lbs MTOW), with >3/4 statute mile approach visibility minimums; Modifying apron areas and taxilanes to increase the efficiency and safety of aircraft parking and circulation; and Acquiring sufficient additional land to accommodate the facility improvements.
The airport development alternatives initially considered are discussed further in the following sections. More detailed information about these airport development concepts including figures illustrating their components can be found in the 2018 Master Plan Update (Appendix E). 3.3.1 Alternative #2 – Extend Runway to the North Meeting FAA Runway Grade Criteria This alternative develops the runway based on the existing airport footprint and extending the runway approximately 999 feet to the north to provide a total length of 7,600 feet. The runway and parallel taxiway would be designed to meet all C-II-5000 standards. Approximately 2,000 feet of the existing runway would need to be reconstructed, as it exceeds the FAA’s runway profile grade requirements. Meeting the longitudinal grade criteria on the Runway 16 end would require substantial earthwork with excavations reaching up to 30 feet deep. The runway extension and widening would likely result in significant excavation in the vicinity of McDeed Creek and notable work to reconstruct the McDeed Creek stream channel. 3.3.2 Alternative #4 – Rotate Runway and Extend North Meeting FAA Runway Grade Criteria This alternative rotates the runway centerline slightly to the northwest to help lessen the extensive earthwork required to extend Runway 16 northward as seen in Alternative #2, while also complying with C-II-5000 runway design standards, including the FAA’s runway profile grade requirements. The alternative requires full reconstruction of the existing 6,601-foot-long runway
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3. ALTERNATIVES CONSIDERED ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT and a 999-foot-long extension to the north to provide the recommended future runway length of 7,600 feet. Excavations through terrain at the north end of the runway would likely be 20 feet deep or less. Rotating the runway reduces the extent of excavation but requires channel work at McDeed Creek and other drainages at the Airport. 3.3.3 Alternative #5 – Extend Runway to the South Meeting FAA Runway Grade Criteria This alternative would shift runway development to the south to avoid the extent of earthwork associated with construction to the north. The Runway 16 threshold would be relocated approximately 1,800 feet south of its current location and the existing pavement would be removed and regraded. Approximately 2,000 feet of the remaining 4,800 feet of existing runway pavement would need to be reconstructed to meet the FAA’s runway profile grade standards. A 2,800-foot- long extension to the Runway 34 end would be constructed to provide the recommended runway length of 7,600 feet. Airport Road would have to be relocated around (or through) the Runway 34 RPZ. The alternative eliminates the existing runway crossing of McDeed Creek and provides an opportunity to move the stream back into a more natural channel. However, extending the runway south and rerouting Airport Road would require crossing Tolman Creek and associated wetlands. 3.3.4 Alternative #6 – Extend Runway to the North with Non-Standard Grade Alternative #6 has a similar layout to Alternative #2 but includes several design options for varying the runway gradient where it may be reasonable to vary from FAA design requirements, while still providing an acceptable level of safety. Departing from runway gradient standards was viewed as a potential measure to make the proposed improvements more feasible from both a constructability and an economic standpoint. Development of Alternative #6 would require the FAA to approve one or more Modifications of Standards (MOS) for runway surface grades. Runway widening would occur to the east side of the existing runway.
The options associated with Alternative #6 considered in the 2018 Master Plan Update are described in the following paragraphs. Like Alternative #2, all of the design options considered for Alternative #6 require substantial excavation of the terrain to the north and east sides of existing airport property and channel reconstruction in McDeed Creek. The extent of excavation required vary by option.
Alternative #6A - Extend Runway to the North with 1.9% Maximum Grade This alternative would maintain a 1.9% slope within the existing runway and would extend the runway 999 feet to the north at the same profile grade of 1.9%. This greatly reduces the earthwork and associated costs, as well as potential impacts to McDeed Creek. This option does not require reconstructing the entire existing 6,601-foot-long runway. This alternative would require two FAA- approved MOS (1.5% maximum longitudinal grade for the central portion of the runway and 0.8% maximum longitudinal grade for the first quarter of Runway 16).
Alternative #6B - Extend Runway to the North with 1.5% Maximum Grade This alternative would reconstruct approximately 1,900 feet of the existing runway at the 16 end to a maximum grade of 1.5% and limit maximum grades on the 999-foot-long runway extension to the
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3. ALTERNATIVES CONSIDERED ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT runway to 1.5% or less. This alternative would limit the maximum excavation depths to about 20 feet. The existing runway profile grade would remain unchanged on about 4,700 feet of the existing runway. This alternative would require an FAA-approved MOS (0.8% maximum longitudinal grade for the first quarter of Runway 16).
Alternative #6C - Extend Runway to the North with 1.3% Maximum Grade This alternative attempts to further limit the depth of excavations associated with a northerly runway extension by maximizing the central portion of the runway to 1.5% grade and reconstructing the initial 1,900 feet of Runway 16 to a 1.3% maximum grade (including the 999- foot-long extension). This would require reconstructing 4,470 feet of the existing runway. This alternative would require an FAA-approved MOS (0.8% maximum longitudinal grade for the first quarter of Runway 16). 3.4 Alternatives Eliminated from Consideration Alternatives that do not meet the purpose and need, or are deemed to be unreasonable to implement at EKS due to other considerations, were eliminated during the forecasting and planning stage and will not be carried forward for analysis in this EA.
The alternatives identified above were evaluated with respect to the primary elements of the purpose and need discussed in Chapter 2. These elements include the ability to provide a 7,600 foot-long by 100-foot-wide runway, adequate runway-taxiway separation distance, clear runway approaches, “mostly” unobstructed 14 CFR Part 77 imaginary surfaces (it is not feasible to completely clear the Horizontal and Conical Surfaces to the east in any of the Airport Improvement Alternatives), and sufficient opportunities for desirable apron area modifications. Table 3.1 identifies the alternatives eliminated from consideration and the reasons for their exclusion.
Table 3.1: Alternatives Eliminated From Consideration
ALTERNATIVE REASONS FOR ELIMINATION Airport Relocation Moving the airport to a new site disregards the investment in property and aviation facilities Madison County, the FAA, and private parties have already made at EKS. Potential sites for a new airport are too far from Ennis and between 4 and 12 miles farther from the community than the existing airport, which is already 4 miles from Ennis. Many potential airport sites encroach on agricultural and grazing lands within conservation easements that generally restrict non- agricultural development. Airport relocation would require owners of hangars or other structures to move existing structures or construct new buildings at the alternate airport site. Lease agreements exist for the existing hangars at the airport and the County would be obligated to buy- out the leases or maintain the existing airport until the leases expire.
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Table 3.1: Alternatives Eliminated From Consideration (Continued)
ALTERNATIVE REASONS FOR ELIMINATION Airport Relocation Preliminary estimates suggest the cost of developing a new airport (Continued) at more than $24 million, the most expensive alternative considered in the 2018 Master Plan Update. Alternative #2 In January 2018, the FAA approved a request from the Sponsor for Extend Runway to the North a MOS to vary from the design standard requiring a 0.8% Meeting FAA Runway Grade maximum runway profile grade at EKS. Developing the runway to Criteria meet FAA grade standards as called for in Alternative #2 is unnecessary with the approval of an MOS allowing for a departure from the grade standard. This alternative requires significant amounts of earthwork (preliminarily estimated at about 1.1 million cubic yards) including excavations up to 30 feet deep in some areas. This poses geotechnical and hydrogeological concerns since excavation to those depths within the alluvial fan on which the airport has been developed have not been investigated. This alternative ranked fourth out of the six improvement alternatives evaluated in the 2018 Master Plan Update and was not identified as Madison County’s preferred development alternative. Preliminary estimates show the cost of this alternative to be considerably higher than other options that extend the runway northward (Alternative #6, Options #6A, #6B, and #6C).
Alternative #4 Rotating the runway and complying with FAA criteria for the runway Rotate Runway and Extend profile grade renders nearly all the existing runway footprint North Meeting FAA Runway unusable for incorporation into the new runway. All 6,601 feet of Grade Criteria the existing runway would need to be reconstructed. Due to the extent of runway reconstruction, this alternative would likely require the longest airport closure time of the improvement alternatives at the existing airport site. While rotating the runway helps limit the depth of excavation at the 16 end of the new runway, it creates a deep fill area on which to build the runway and parallel taxiway. Rotating the runway could encroach onto a developed property on the southwest end of the existing airport. This alternative had the lowest overall ranking among airport improvement alternatives examined in the 2018 Master Plan Update.
Alternative #5 This alternative varies substantially in concept from previous airport Extend Runway to the South planning at EKS. Extending the runway south has been previously Meeting FAA Runway Grade evaluated and dismissed in past Master Plan efforts for EKS due to Criteria conflicts with Airport Road and the high costs and likely environmental impacts (land acquisition, disruption of agricultural use, disruption of Airport Road, multiple stream crossings, and wetland encroachment) of reconstructing the roadway south of the new Runway 34 end and associated RPZ.
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Table 3.1: Alternatives Eliminated From Consideration (Continued)
ALTERNATIVE REASONS FOR ELIMINATION Alternative #5 This alternative varies substantially in concept from previous airport (Continued) planning at EKS. Extending the runway south has been previously Extend Runway to the South evaluated and dismissed in past Master Plan efforts for EKS due to Meeting FAA Runway Grade conflicts with Airport Road and the high costs and likely Criteria environmental impacts (land acquisition, disruption of agricultural use, disruption of Airport Road, multiple stream crossings, and wetland encroachment) of reconstructing the roadway south of the new Runway 34 end and associated RPZ. Although this alternative reduces the amount of earthwork necessary at the north end of the airfield, it requires the removal of 1,800 feet of the runway pavement and grading the former runway area to clear the object free area and eliminate airspace penetrations. The alternative requires reconstructing 2,000 feet of the remaining 4,800 feet of the existing runway due to incompatible longitudinal profile grades. A 2,800-foot-long runway extension to the south would be needed to provide the recommended 7,600-foot-long runway at EKS. Other alternatives require extensions of only about 1,000 feet in length. This alternative requires the most land acquisition (57 acres) among improvement alternatives considered, and likely requires the acquisition of a residence located southeast of the Airport. Public opposition to this alternative would be expected due to the need to realign about 1.5 miles of Airport Road, acquire right-of- way, acquisition of the residence located southeast of the Airport, and construction of a new road through land under a conservation easement. Development of a new road would likely affect Tolman Creek and associated wetlands. Preliminary estimates placed the cost of this alternative considerably higher than the Alternative #6 options that would extend the runway to the north. This alternative had the second lowest overall ranking among airport improvement alternatives examined in the 2018 Master Plan Update.
Alternative #6A Although this alternative was preferred by the Sponsor, the FAA Extend Runway to the North stated during the 2018 Master Plan Update process the agency with 1.9% Maximum Profile could not approve an MOS to exceed the 1.5% maximum profile Grade grade criteria. Because this alternative does not provide an acceptable level of safety, the proposed improvements would not be eligible for FAA assistance. Without FAA funding assistance, development and maintenance costs for the Airport must be assumed entirely by Madison County. This alternative would also increase the overall liability to Madison County for operating a non-standard airport. This alternative was eliminated from consideration in the 2018 Master Plan Update for the reasons identified above.
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Table 3.1: Alternatives Eliminated From Consideration (Continued)
ALTERNATIVE REASONS FOR ELIMINATION Alternative #6C In January 2018, the FAA approved a request from the Sponsor for Extend Runway to the North a MOS to construct the runway with a maximum runway profile with 1.3% Maximum Profile grade of 1.5% (for Alternative #6B). With approval of this MOS, Grade there is no longer a need to pursue a MOS for maximum runway grades of 1.3% and without an MOS, the proposed improvements would not be eligible for FAA assistance. This alternative offers only a minimal improvement in the runway grade over the first quarter of extended Runway 16’s length when compared with a design based on the approved MOS allowing a maximum profile grade of 1.5%. This alternative requires reconstruction of about 4,470 feet of the existing runway. Any potential cost savings due to decreased earthwork is offset by the increased costs associated with reconstructing the existing runway. Due to the extent of runway reconstruction required, the anticipated time of airport closure necessary to construct this alternative would be significantly more than other alternatives. Option #6C ranked third out of the six improvement alternatives evaluated in the 2018 Master Plan Update. Preliminary estimates placed the cost of this alternative well above the estimated cost of Option #6A and slightly above the estimated cost of Option #6B.
3.5 Alternatives Carried Forward for Analysis The two alternatives evaluated in detail as part of this EA are:
No Action Alternative. Alternative #6B – Extend Runway to the North with 1.5% Maximum Grade.
As required, the No Action Alternative has been carried forward for analysis because it provides a baseline for comparing the potential effects of other reasonable alternatives.
Alternative #6B is the Sponsor’s Proposed Action because it meets the stated purpose and need for airport improvements, has been deemed reasonable to implement at EKS, and was also ranked highest of the airport improvement alternatives reviewed in the 2018 Master Plan Update. The Proposed Action includes modifications and improvements that would provide a C-II-5000 facility, with aircraft >12,500-lbs but less than 60,000-lbs with occasional use of aircraft up to 114,850 MTOW, at EKS; however, this alternative requires an FAA-approved MOS for varying from the design standard requiring a 0.8% maximum runway profile grade for the initial 1,900 feet (the first quarter of the runway’s length) of extended Runway 16. The FAA approved the MOS on March 13, 2018, which allows the Sponsor to reconstruct approximately 2,000 feet of the existing runway to
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1.5% maximum slope and construct the 999-foot-long runway extension at 1.5% maximum slope. Approximately 600 feet of the existing runway would also need to be reconstructed to meet the longitudinal grade criteria for vertical curve length between grade changes.
A detailed description of each alternative and associated actions follows. 3.5.1 No Action Alternative The No Action Alternative does not include any improvements to the Airport, but the Sponsor would still need to maintain the Airport’s current facilities. The configuration and layout of EKS would be unchanged from present conditions under this alternative. EKS has been planned and constructed as a B-II-5000 facility, with aircraft <12,500-lbs MTOW; however, current aviation activity and recent forecasting show the critical design aircraft category for the Airport has changed to C-II-5000, with aircraft >12,500-lbs but <60,000-lbs MTOW with occasional use of aircraft up to 114,850 MTOW.
As configured, the Airport does not conform to all current FAA design and safety standards for the critical aircraft. The current 6,601-foot-long runway is shorter than the recommended minimum length of 7,600 feet based on the performance characteristics of the newly identified critical aircraft, operating conditions, and site characteristics at EKS. The existing runway needs to be widened from 75 feet to 100 feet to meet the FAA’s design standards for a C-II-5000 facility. The runway pavement was not designed to accommodate regular use by the fleet of C-II aircraft with >12,500 pounds but < 60,000 pounds MTOW with occasional use of aircraft up to 114,850 MTOW, and approach visibility minimums of not lower than 1-mile (5,000-feet RVR).
Additionally, profile grades for some sections of the existing runway do not meet AAC C design standards. The existing lateral separation distances between the centerlines of the runway and parallel taxiway, and between the runway centerline and aircraft parking areas would continue to be insufficient relative to C-II-5000 design standards. The runway Object Free Area (OFA) also has penetrations along the east side, as sufficient land is not available for the perimeter fence line to be clear of the OFA. The layout of apron and aircraft parking areas would continue to be inefficient with limitations for parking larger and heavier aircraft, especially within the southern apron.
When airport Sponsors accept funds from FAA-administered airport financial assistance programs, they must agree to certain obligations (or assurances). These obligations require funding recipients to maintain and operate their facilities safely and efficiently and in accordance with specified conditions. Therefore, Madison County is obligated to comply with the FAA’s minimum design standards and safety requirements to ensure EKS is always operated in a safe and serviceable condition. Failure to meet required assurances could potentially affect the County’s ability to secure FAA funding assistance for facility maintenance and improvement projects.
Since the No Action Alternative requires no additional land and makes no improvements, there are no project improvement costs. The 2018 Master Plan Update estimates future rehabilitation and maintenance costs would exceed several million dollars, as some pavements are beyond their useful lives and in need of immediate reconstruction or major rehabilitation. Implementing maintenance activities alone does nothing to help the Sponsor meet recommended FAA design
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3. ALTERNATIVES CONSIDERED ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT standards and safety requirements for a C-II-5000 facility, with aircraft >12,500-lbs but <60,00-lbs MTOW with occasional use of aircraft up to 114,850 MTOW.
This alternative does not meet the purpose and need and does not represent a financially sound action by Madison County. However, NEPA regulations require the FAA to consider a “no action” alternative (40 CFR § 1502.14(d)). The No Action Alternative serves to describe the current and future state of the affected environment without considering the potential impacts of the proposed action or project.
Figure 3‐2 shows the airport layout under this alternative. Figures 1‐2 and 1‐3 in Chapter 1 provide additional detail about the existing configuration of EKS.
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FIGURE 3-2: No Action Alternative
No Action: B-II Runway
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3.5.2 Alternative #6B – Extend Runway North with 1.5% Maximum Grade (Proposed Action) The Proposed Action would provide a 7,600-foot-long by 100-foot-wide runway, meeting C-II-5000 standards (with FAA-approved MOS), capable of accommodating 75% of the GA fleet at >12,500-lbs and <60,000-lbs MTOW with occasional use of aircraft up to 114,850 MTOW, on a 16/34 orientation. Alternative #6B would maintain the existing threshold for Runway 34 but extend the threshold for Runway 16 about 999 feet to the north at a maximum grade of 1.5%. Approximately 4,000 feet of the existing runway would be incorporated into the new runway, but some 2,000 feet of the existing runway would be reconstructed to 1.5% maximum grade, with another 600 feet being reconstructed to lengthen the vertical curves and make more gradual transitions between changes in runway grade.
Runway widening would occur to the east to improve the required separation distance between the runway and parallel taxiway and maximize available apron space fronting the existing hangars. Reconstructed and widened sections of the runway would receive new asphalt pavement and the remaining portion of the existing runway would receive a 2-inch structural HMA overlay to increase the strength of the runway pavement. A full-length parallel taxiway at a runway to taxiway separation distance of 300 feet will be provided.
The proposed work on Runway 16/34 would also include relocating the existing MIRL system to accommodate the wider runway and extending the MIRL system along both sides of the new runway extension area. Together with the proposed work on the runway, the existing electrical vault equipment must be rehabilitated or replaced to handle expansions of the MIRL and MITL systems. Additionally, relocating one or both of the PAPIs for Runway 16/34 and expanding them to “four-box” units (L-880) to accommodate for jet aircraft operations.
Other actions associated with the Proposed Action include:
Fee acquisition of 3.17 acres of new airport land from Tracts 4-A and 4-B and securing a perpetual easement on 17.82 acres of State of Montana land (Tract 6) north of the Airport. Installing 9-foot high wildlife fence around the perimeter of the Airport property (including State of Montana land with perpetual easement(s). Constructing 2,215 feet of the partial parallel taxiway (between Taxiways A-2 and A-3) at an increased separation distance from the runway and reconstruct about 870 feet of the partial parallel taxiway between taxiway A-4 and the south edge of the central apron area. Extending the parallel taxiway to the end of extended Runway 16. Reconstructing Taxiways A-2 and A-4 connecting Runway 16/34 and the parallel taxiway. Installing new taxiway edge lighting. Demolishing or relocating airport buildings including the existing pilot’s shack/public room, vault toilet, shed, and two hangars. Reconstructing the South Apron to accommodate the Runway 16/34 OFA and increasing the strength of the apron pavement.
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Extending Taxilane C and construct a portion of Taxilane D to improve hangar access. Construction of hangars along Taxilanes C and D. Relocating the Madison County-owned NAVAIDs (wind cone, segmented circle, and beacon) and AWOS III/P. Relocate/rehabilitate electrical vault and vault equipment. Relocating the self-service fuel dispensing unit beyond the Runway 16/34 OFA and Taxiway Safety Area for Taxiway A. Resolving terrain, and any overlying airport fencing, penetrations to 14 CFR Part 77 imaginary surfaces – primary, approach, transitional surfaces only, as clearing horizontal and conical surfaces is not practical along the east side. Amending the existing instrument approach and departure procedures at EKS.
Figure 3‐3 illustrates the general layout of this alternative. A more detailed drawing of the proposed future and potential ultimate improvements at EKS can be found in Appendix B (Airport Layout Plan).
The Sponsor is also seeking consideration of Airport Improvement Program (AIP) funding to reimburse Madison County for the acquisition of a parcel from the Longhorn Ranch, Tract 29-A-1, and portions of Tracts 20-A, 20-B, 13-A, and 13-B. These properties were purchased with local funds as discussed in Section 1.1.2 and shown on Figure 1‐2. These parcels lie on the west side of the Airport and are needed to accommodate the required OFA for the Airport to meet C-II-5000 design standards. These properties became available during the planning process for the 2018 Master Plan Update and this Environmental Assessment, and no federal funding could be contributed towards their acquisition while these processes were underway.
The planning level cost of the Proposed Action is estimated to be $14.92 million. The FAA’s AIP currently provides grants covering 90% of eligible improvement costs for general aviation airports. The additional 10% of project costs (and all other ineligible costs) are the responsibility of the airport Sponsor. Other FAA discretionary funding may also be available to help meet the cost of airport improvements.
Construction of the improvements would likely span several years, being funded in phases with separate AIP projects/grants.
The South Apron reconstruction, along with the adjacent portion of the partial parallel taxiway and connecting taxiway rehabilitation(s), and Taxilane C extension is anticipated to occur in 2020. Construction duration would last an estimated 3 months; however, limited runway closures would be necessary (only associated with reconstruction of the connecting taxiway and estimated at less than 5 working days in total).
The majority of the improvements are anticipated to occur in 2020 and 2021, with runway and parallel taxiway extension, and runway widening, and strengthening to occur. Associated items would include: safety area grading, object free area grading and clearances (including relocation of the boundary fence with replacement with 9-foot-high wildlife fence, and relocation of the segmented circle, wind cone, and AWOS III/P), runway lighting replacement/relocation/extension,
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The work is likely to span two construction seasons. Much of the earthwork within the runway extension and approach area can be completed in advance with limited runway closures. It is anticipated that the existing runway improvements, widening, strengthening, and all paving would then be completed the following construction season. This would cause at least a 3-month closure for completion. It is desired to complete this work in the spring or early summer, to avoid the busier traffic season, which begins in July and extends through September.
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FIGURE 3-3: Alternative #6B: Extend Runway North with 1.5% Maximum Grade (Proposed Action)
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ENVIRONMENTAL ASSESSMENT ENNIS BIG SKY AIRPORT MADISON COUNTY, MT
4. AFFECTED
ENVIRONMENT
ROBERT PECCIA & ASSOCIATES
4. AFFECTED ENVIRONMENT ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT
AFFECTED ENVIRONMENT 4.1 Introduction This Chapter describes the affected environment in which the alternatives under consideration would occur. The affected environment is the area impacted by the proposed alternatives. It includes the ecological, cultural, social, aesthetic and economic conditions of the area. The purpose of describing the affected environment is to define the context in which the impacts would occur.
The FAA’s Environmental Impacts: Policies and Procedures (Order 1050.1F, dated July 16, 2015) serves as the agency’s policy and implementing procedures for compliance with NEPA. This order requires the following environmental impact categories to be considered in this EA:
• Air Quality • Visual Effects (Including Light Emissions) • Coastal Resources • Natural Resources and Energy Supply • Land Use • Climate • Department of Transportation Act: Section 4(f) • Noise and Compatible Land Use • Farmlands • Socioeconomics, Environmental • Biological Resources (Including Fish, Wildlife Justice, and Children’s Environmental and Plants) Health and Safety Risks • Hazardous Materials, Solid Waste, and • Water Resources (Including Surface Pollution Prevention Waters, Floodplains, Groundwater, • Historical, Architectural, Archaeological, and Wetlands, and Wild and Scenic Rivers) Cultural Resources
This EA examines areas where physical improvements, such as extending and widening the runway, constructing a full-length parallel taxiway, relocating NAVAIDS, constructing taxiway and apron improvements, and installing perimeter fencing would occur. In addition, resources on lands beyond the Airport property have been analyzed to determine the potential for effects associated with making improvements at the facility. 4.2 Air Quality Background
The Clean Air Act (CAA) requires the U.S. Environmental Protection Agency (EPA) to set National Ambient Air Quality Standards (NAAQS) (40 CFR Part 50) for pollutants considered harmful to public health and the environment. The CAA established two types of national air quality standards: Primary Standards and Secondary Standards. The pollutants of concern are called
“criteria pollutants” and include carbon monoxide (CO), sulfur dioxide (SO2), nitrogen dioxide
(NO2), ozone (O3), particulate matter less than or equal to 10 microns aerodynamic diameter
(PM10), fine particulate matter less than or equal to 2.5 microns aerodynamic diameter (PM2.5), and lead. Volatile organic compounds (VOCs) are not a criteria pollutant and therefore no ambient air standards have been established for this pollutant. Since VOCs, however, react with NOx in sunlight to form O3, this analysis includes VOCs and NOx emissions, and refers to them as ozone precursor pollutants.
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The NAAQS Primary Standards set limits to protect public health, including the health of at-risk populations such as people with pre-existing heart or lung disease (e.g. asthmatics), children, and older adults. Secondary Standards set limits to protect public welfare, including protection against visibility impairment, damage to animals, crops, vegetation, and buildings.
The CAA allows state agencies to adopt and enforce more protective air pollution regulations than EPA; however, states are not allowed to have weaker air pollution regulations than those established by the EPA. Montana has adopted air quality standards, known as the Montana Ambient Air Quality Standards (MAAQS), similar to the NAAQS for the criteria pollutants.1 The MAAQS establish statewide targets for acceptable amounts of ambient air pollutants to protect human health.
Areas where air pollution levels do not exceed the NAAQS are designated by EPA as “attainment” areas. Areas where pollutant levels exceed the NAAQS may be designated as “nonattainment” areas. An area that has been designated as non-attainment in the past, but that now complies with the NAAQS, is classified as a “maintenance” area. The EPA is responsible for designating areas that are attainment, nonattainment, or maintenance for each of the criteria pollutants. States are required under the CAA to develop State Implementation Plans (SIPs) for pollutants that are either non- attainment or maintenance to achieve or maintain the NAAQS within timeframes set under the CAA.
Madison County does not contain any designated nonattainment or maintenance areas for any of the NAAQS or MAAQS. Thus, Madison County is in attainment for NAAQS.2
The importance of identifying if the airport is within a nonattainment or maintenance area relates to requirements for an air quality analysis before a project can be approved by a federal agency. The General Conformity Rule of the CAA ensures that federal actions occurring in nonattainment or maintenance areas must first be shown to conform with the current approved SIP; the purpose of conformity is to ensure that the proposed federal action would not create new exceedances of the NAAQS or worsen an existing exceedance. Since Madison County is an area designated as attainment for the NAAQS, the proposed improvement project at the Ennis Big Sky Airport is not subject to the General Conformity Rule. Ambient Air Quality Montana Department of Environmental Quality (MDEQ) conducts air measurements at 22 locations within the state. No air quality monitoring stations exist in Madison County. In general, air quality is good and there are no notable sources of air pollutants in the project area. Like other areas of Montana, air quality and visibility are occasionally affected by smoke from wildfires during the summer months. 4.3 Coastal Resources Federal activities involving or affecting coastal resources are governed by the Coastal Barriers
1 http://deq.mt.gov/Air/2017Air/citguide/understanding 2 USEPA Green Book, accessed on 3-21-2018 at https://www3.epa.gov/airquality/greenbook/anayo_mt.html
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Resource Act and the Coastal Zone Management Act. There are no coastal barrier islands or designated coastal zones in the State of Montana. Therefore, none of the alternatives carried forward would affect coastal resources. 4.4 Land Use In general, local land use plans should be consistent with airport operations and likewise, airport operations should be generally consistent with local land use plans to the extent possible. Existing Land Uses at and Near the Airport
Lands in Section 31, Township 6 South, Range 1 East, which include the majority of the existing airport property, were originally subdivided as part of the Shining Mountains Air Park development. These parcels were initially marketed towards individuals seeking to develop residences with convenient access to aviation facilities. Residences exist on some of the 10-acre or larger parcels within the Shining Mountains Air Park subdivision along the east and west sides of the Airport. The tracts adjoining the Airport’s eastern boundary are approximately 6.4-acres in size, having been reduced by previous airport improvements. Lands north and south of the existing airport property consist of State of Montana Trust lands and private range lands and are currently used for livestock grazing and other agricultural purposes.
The Longhorn Ranch lies on the north and northeast sides of the Airport. A conservation easement was established on about 8,300 acres of the Longhorn Ranch in 1982. The general purpose of the conservation easement is to preserve, protect, and enhance the natural character and open space and maintain water quality on the ranch lands. The conservation easement prohibits subdivision of the property and subsequent development for residential, commercial or industrial uses. In general, the conservation easement prohibits the type of development that could be incompatible with airport operations. Acquisition of Longhorn Ranch property for airport use meant that 6.41 acres of the ranch property was voluntarily sold to Madison County for airport use in perpetuity. The 6.41- acre parcel acquisition was acquired as a “boundary line adjustment” between the two parcels and therefore exempt from subdivision regulations. The conservation easement will continue to be in effect on the acquired 6.41-acres as well as the remaining Longhorn Ranch property. The acquisition of the 6.41-acres will meet its intended use of providing OFA clearance and ultimate boundary fencing with the conservation easement requirements attached.
The existing airport property boundaries are shown on Figure 4‐1. Existing airport facilities are primarily developed on land owned in fee by Madison County. However, the north end of Runway 16-34 and the RPZ for Runway 16 are within a perpetual easement from State of Montana (Tracts 2 and 3). A small portion of the RPZ for Runway 34 also exists on an easement from Danny C. and Darcy Stroud (Tract 4).
If Runway 16-34 is extended to the north as proposed under the Proposed Action, an additional perpetual easement from the State of Montana will need to be obtained to enable the recommended northerly extension of Runway 16 and provide runway protection for Runway 16-34. The acquisition of Tracts 4-A and 4-B under the Proposed Action will accommodate the required Object
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Free Area (OFA) for the Airport to meet C-II-5000, with MTOW greater than 12,500-lbs but less than 60,000-lbs, design standards. Land Use Controls on Lands Near the Airport
Airport Affected Area
As required by Title 67, Chapter 7 of Montana Code Annotated (Airport Compatibility Act), the Madison County Board of Commissioners adopted Resolution 30-2014 which established an Airport Affected Area (AAA) and associated regulations for Ennis Big Sky Airport on August 11, 2014. The AAA (shown in Figure 4‐2) consists of the land and space above the ground surface at and around the Airport and includes zones which are delineated areas on the ground which lie beneath the horizontal surface, the conical surface, the primary surface(s), the approach surfaces and the transitional surface(s) as described in 14 CFR, Part 77.
The AAA is intended to promote the public health, safety and general welfare of airport users and persons and property near the Ennis Big Sky Airport by addressing the effects of noise, height of structures and trees, lighting, and land use in the vicinity of the facility. The regulations protect the transportation infrastructure provided to the community by the Airport from incompatible development and protect the Airport from personal or property injury claims due to noise and hours of operations. The regulations include permitting and enforcement provisions, so the County can monitor and control the height of structures or trees and land uses in the AAA and advise members of the public wishing to change or add structures, trees or land uses that legal restrictions apply to their proposed activities.
Land Use Plans Land use planning on rural lands in Madison County is conducted by the Madison County Planning Office. Decisions on land use matters are the responsibility of the Madison County Board of Commissioners. The County has established an 11-member Planning Board that meets periodically throughout the year. The Planning Board serves in an advisory capacity to the Planning Office and the Board of Commissioners on matters related to land use and subdivisions.
Madison County has also established a 7-member Airport Board to serve as an advisory board to the elected Board of Commissioners; however, the Board of Commissioners has responsibility and the authority for making decisions regarding the administration and operation of the Ennis Big Sky Airport. Members of the Airport Board are appointed by the Board of Commissioners and serve 3- year terms and must be residents of Madison County. The Airport Board provides representation and input from their communities and the broader Madison County areas served by EKS and the Twin Bridges Airport.
The County Board of Commissioners adopted the Madison County Growth Policy 2012 in March 2013 under Resolution 11-2013. The Growth Policy is an update of the County Growth Policy adopted in 2006. Growth policies reflect the collective vision of citizens and provide direction for making decisions about land use, economic development and capital investments. The Madison County Growth Policy 2012 advocates that high quality public services (such as transportation
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Figure 4-1: Existing Airport Property
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Figure 4-2: Airport Affected Area (AAA) for Ennis Big Sky Airport
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4. AFFECTED ENVIRONMENT ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT infrastructure at the Ennis Big Sky Airport) be provided to local residents and visitors in safe, fair and cost-effective ways.
Conservation Easements Voluntary conservation easements exist throughout Madison County, which enable willing landowners and willing easement holders to limit development, continue agricultural use, and promote conservation on individual properties. The Madison County Growth Policy 2012 notes conservation easements are in effect on approximately 301,820 acres (about 29%) of the private land in the county. Figure 3‐1 in Chapter 3 provides an indication of the amount of land held in conservation easements in the Madison Valley. Conservation easements held by the Montana Land Reliance exist on Longhorn Ranch properties north and west of the Airport and on Granger Ranch properties located south and west of the Airport.
Land Use Compatibility The compatibility of existing and planned land uses near an airport is typically associated with the extent of the airport’s noise impacts and with the types of land uses that may adversely affect aircraft operations. A noise sensitive area is an area where noise interferes with normal activities associated with its use. Examples include, but are not limited to, residential, educational, health, and religious structures and sites, parks, recreational areas (including areas with wilderness characteristics), wildlife refuges, and cultural and/or historical sites where a quiet setting is a generally recognized feature or attribute. Examples of land uses that may adversely affect aircraft operations include municipal landfills, wetland mitigation sites, water or wastewater impoundments, or other uses that may attract wildlife species hazardous to aviation.
The FAA has determined the cumulative noise energy exposure of individuals to noise from aviation activities must be established in terms of day/night average noise level (DNL). The FAA requires the DNL metric for airport environmental studies because it uses a single number to describe the constantly fluctuating noise levels at a receiver location during an average annual 24-hour day. The area exposed to noise levels at DNL 65 decibels (dB) and above are of interest for airports. This is because the FAA’s guidelines show that residential areas and other noise-sensitive land uses are normally incompatible in areas where noise levels above DNL 65 dB occur.
Scattered residences, typically built on 10-acre or 20-acre parcels, exist to the east and west sides of the Airport. Some of these residential properties were originally built as part of the Shining Mountains Air Park development surrounding the Airport. A review of aerial photographs indicates the only structures within the DNL 65 dB and above noise contours are airport-related buildings; there are currently no residences (or other noise sensitive land uses) located in the DNL 65 dB (or greater) noise contours at EKS. Section 4.13 Noise in this chapter provides background information about noise metrics and discusses the aircraft noise modeling conducted for the existing airport configuration.
A review of current land uses shows there are no land uses or surface waters at the Ennis Big Sky Airport that may attract wildlife species hazardous to aviation activities. There are no landfills, large wetlands areas, ponds, or wastewater treatment facilities near the Airport; however, several intermittent streams cross the airport property including McDeed Creek, Boulder Creek, and two
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4. AFFECTED ENVIRONMENT ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT unnamed tributaries to Boulder Creek. There are also fringe wetland areas that are associated with portions of McDeed Creek.
Residential Through The Fence (RTTF) Access The Ennis Big Sky Airport has existing Residential Through The Fence (RTTF) access points allowing some adjacent property owners to enter the airfield. Madison County has an FAA- approved RTTF Access Agreement, approved on April 16, 2015, which remains in effect until substantial changes are proposed to the access agreement or until April 16, 2035. All RTTF users must sign the Access Agreement prior to being authorized to utilize the established access points. 4.5 Department of Transportation Act: Section 4(f) Section 4(f) of the U.S. DOT Act of 1966 (now codified at 49 U.S.C. § 303) protects significant publicly owned parks, recreational areas, wildlife and waterfowl refuges, and public and private historic sites. Section 4(f) provides that the Secretary of Transportation may approve a transportation program or project requiring the use of any publicly owned land from a public park, recreation area, or wildlife and waterfowl refuge of national, State, or local significance or land from an historic site of national, State, or local significance only if there is no feasible and prudent alternative to the use of such land and the program or project includes all possible planning to minimize harm resulting from the use. Historic or archaeological properties are typically only protected under Section 4(f) if the properties are listed, or eligible for inclusion, on the National Register of Historic Places (NRHP).
There are no federal, state or local parks, recreation areas, or wildlife refuges adjacent to the Ennis Big Sky Airport property; however, several Section 4(f) resources exist in the general project area. The Beaverhead-Deerlodge National Forest is located about 1.5 miles east of the airport property. At its nearest point, the Lee Metcalf Wilderness (within the Beaverhead-Deerlodge National Forest and managed by the Bureau of Land Management and the U.S. Forest Service) is located about 2.5 miles southeast of the Airport. National Forest lands along Shell Creek east of the Airport are identified as potential additions to the Lee Metcalf Wilderness and managed to protect wilderness characteristics and values and to provide semi-primitive non-motorized recreation opportunities.
The Madison Valley Important Bird Area (IBA) exists along the Madison River about 3 miles west of the Airport.
Figure 4‐3 shows the location of the Ennis Big Sky Airport in relation to the Beaverhead-Deerlodge National Forest, Lee Metcalf Wilderness, and the Madison Valley IBA.
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Figure 4-3: Potential Section 4(f) Lands Near the Ennis Big Sky Airport
BEAVERHEAD‐DEERLODGE NATIONAL FOREST
Ennis Big Sky Airport
BEAVERHEAD‐DEERLODGE NATIONAL FOREST
A review of the online listing of grants maintained by the National Park Service showed no public recreation sites near the Airport that have been acquired or improved with the Department of the Interior’s Land and Water Conservation Fund (LWCF).
Cultural resource surveys were conducted for lands at and near the Airport in September 2016, November 2017, and June 2019. The 2016 survey was focused on existing airport lands and the work completed in 2017 examined lands east and north of the airport property already acquired or in the process of being acquired by Madison County at the time. The 2019 survey included a pedestrian inventory of a portion of Tract 4-B and visually observed the property within Tract 4-A that was readily visible beyond the existing airport boundary fence and from Tract 4-B. Tract 4-A could not be inventoried because the landowner denied access for a survey. If Tract 4-A is acquired under the Proposed Action, the property will be surveyed prior to any disturbance.
Tracts 4-A and 4-B, which are proposed for acquisition under the Proposed Action, are privately- owned residential tracts at the southeast edge of the airport property. Tract 4-A consists of vacant and unimproved subdivision land. Tract 4-B is an improved tract with a residence and out
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4. AFFECTED ENVIRONMENT ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT buildings. The portion of the Tract 4-B affected by the proposed improvements at EKS has been highly disturbed due to residential access road and parking area development and surface grading. Tracts 4-A and 4-B would serve as part of the expanded OFA for the runway and be affected by the relocation of boundary fencing along the east perimeter of the Airport.
The cultural resource surveys recorded two historic sites in the vicinity of EKS—the Granger Ditch (24MA2400) and isolated find IF-CML-01. The Granger Ditch, a 14-mile long irrigation ditch dating to 1902, crosses the extreme western portion of the Airport. The Granger Ditch was determined eligible for the NRHP in concurrence with the Montana State Historic Preservation Office (SHPO). IF-CML-01 consists of two historic artifacts (the remnants of an old bottle and enamel ware) and one prehistoric artifact (a basalt or dacite flake) found on the southeast side of the airport property. The isolated find is not eligible for the NRHP because the artifacts likely originated from an adjacent property (Tract 4-B). The cultural resources inventory in 2019 did not identify any cultural materials on Tract 4-B so the origins of the artifacts discovered on the airport remain undetermined.
The FAA determined that the isolated find was ineligible to the NRHP and the Granger Ditch was eligible to the NRHP in a letter dated December 6, 2016, and SHPO concurred in a letter dated December 16, 2016 (See Appendix A). Therefore, of these historic properties, only the Granger Ditch is a Section 4(f) resource. 4.6 Farmlands Farmlands are defined as those agricultural areas considered important and protected by Federal, state, and local regulations. The Farmland Protection Policy Act (FPPA), found at 7 U.S.C. § 4201- 4209, regulates Federal actions with the potential to convert farmland to non-agricultural uses. Specifically, the FPPA regulates farmland identified as prime, unique, or of statewide or local importance by the U.S. Department of Agriculture Natural Resources Conservation Service (NRCS).
Any airport development action funded under the AIP or subject to FAA approval that would permanently convert areas designated farmland to a non-agricultural use is subject to FPPA coordination. The FPPA does not apply to land already committed to "urban development or water storage". FAA guidance indicates airport developed lands are considered lands under urban development. Therefore, when evaluating potential impacts on farmlands, it is necessary to evaluate only those areas designated as important and are in active agricultural use or not yet developed.
Table 4.1 presents soils (listed by soil map unit number and name) occurring within the Ennis Big Sky Airport project area based on maps available from the NRCS Web Soil Survey website. As the table shows, three of the soils in the project area are considered Farmland subject to the FPPA based on their classifications as Farmland of Statewide Importance and Farmland of Local Importance.
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Table 4.1: Soils Within the Project Area at Ennis Big Sky Airport Soil Map Unit # Soil Unit Name NRCS Classification 11 Attewan loam, cool, 2-8% slopes Farmland of statewide importance 12 Attewan cobbly loam, cool, 2-8% slopes Farmland of local importance 17 Beaverell cobbly loam, cool, 0-6% slopes Farmland of local importance 105 Rivra very gravelly sandy loam, cool, 2-4% slopes Not Prime Farmland
Source: NRCS Web Soil Survey website. Available at: http://websoilsurvey.nrcs.usda.gov/app/WebSoilSurvey.aspx. Accessed November 2017. 4.7 Biological Resources (Including Fish, Wildlife and Plants) Information about fish, wildlife and plants occurring on and adjacent to Ennis Big Sky Airport was obtained through a field survey conducted by a biological resources consultant in September 2016, literature searches, and by coordinating with agencies such as the U.S. Fish and Wildlife Service (USFWS), the Montana Fish, Wildlife and Parks (MFWP), and the Montana Natural Heritage Program (MNHP). Fisheries Four intermittent drainages pass through the project area at the Ennis Big Sky Airport—McDeed Creek, Boulder Creek and two unnamed tributaries to Boulder Creek. In addition, the Granger Ditch crosses the western portion of the airport property. As noted in the Ennis Big Sky Airport Biological/Wetland Resources Findings memorandum (found in Appendix D of this EA), none of these intermittent drainages or waterways provide aquatic or fish habitat and none are managed as sport fisheries by the MFWP. The nearest sport fishery is Bear Creek (a tributary to Odell Creek of the Madison River watershed), which is located over a mile west of the project area. General Wildlife Resources A variety of wildlife inhabits the lands on and surrounding the airport property. Adequate forage, shelter, and movement corridors for many species exist within the project area. However, due to the concentration of human, aircraft, and vehicular activity associated with the Airport and other development on nearby lands, significant displacement of wildlife species to adjacent properties has already likely occurred. A 4-foot high fence with three strands of braided wire and a bottom section made of welded wire has been installed around the perimeter of the existing airport property. Fencing adjustments have not yet been made for newly acquired lands along the east side of the Airport.
The most common wildlife found on lands near the Ennis Big Sky Airport include pronghorn antelope, elk, moose, mule deer, small mammals and rodents, a variety of songbirds, hawks, and other raptors. Wildlife species that were identified during the 2016 field view included pronghorn and white-tailed jack rabbit. Evidence of other wildlife included deer scat, ground squirrel burrows, and small trails (likely from deer mice). Other species may occur within and near the project area, including red fox, striped skunk, coyote, and an occasional mountain lion. A garter snake was also seen during the field review; however, reptiles and amphibians likely do not frequent the area because of its arid nature.
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Plants Vegetation at and around the Ennis Big Sky Airport can be classified as the Intermountain Valley Grassland and Meadow vegetation sub-type. Numerous cool weather grasses (fescues, wheatgrasses, and quackgrass) and sedges exist on lands at and near the Airport as well as the occasional prickly pear cactus. Biologists conducting the field review also noted areas around the airport with meadow goat’s-beard, small tumble-mustard, and aster species. Dominant vegetation in fringe wetland areas along McDeed Creek includes creeping bentgrass (Agrostis stolonifera), Baltic rush (Juncus balticus), and long-styled rush (Juncus longistylis).
Noxious Weeds Noxious weeds cause the loss of wildlife habitat, displace native plant species, reduce forage production for livestock and crop production, contribute to soil erosion and soil sedimentation, and adversely affect recreational value and uses of Montana’s lands. The Montana County Noxious Weed Control Law (MCA 7-2101 through 2153) defines noxious weeds as being any exotic plant species that may render land unfit for agriculture, forestry, livestock, wildlife, or other beneficial uses, or that may harm native plant communities. According to the Montana Noxious Weed List (effective February 2017) maintained by the Montana Department of Agriculture, there are 35 state- designated noxious weeds and 5 additional regulated plant species. These species have been assigned various priorities (1A, 1B, 2A, 2B, and 3) based on the number of acres infested and management criteria within the state.
The Madison County Weed District has designated 34 noxious weeds on its Declared Noxious Weed List. These include Category I, Category II, and Category III and IV weeds that correspond with state designated noxious weeds. In addition, two other species—Field Scabious and Musk Thistle—have been designated as noxious weeds in Madison County.
Biologists reviewing the airport property and nearby lands in September 2016 observed several County noxious weed species including thistles. It was difficult to ascertain the true extent of invasive species and noxious weeds that may occupy the area due to heavy grazing outside of the airport property and routine mowing conducted for safe airport operations. Migratory Birds and Eagles
Migratory Birds The Migratory Bird Treaty Act (MBTA) and Executive Order 13186 “Responsibilities of Federal Agencies to Protect Migratory Birds” provide protection for migratory bird species including protection of their nests and eggs. Under the MBTA, it is unlawful to pursue, hunt, take, capture or kill; attempt to take, capture or kill; possess, offer to or sell, barter, purchase, deliver or cause to be shipped, exported, imported, transported, carried or received any migratory bird, part, nest, egg or product, manufactured or not. Direct disturbance of an occupied (with birds or eggs) nest is prohibited under the law. The destruction of unoccupied nests of eagles; colonial nesters such as cormorants, herons, and pelicans; and some ground/cavity nesters such as burrowing owls or bank swallows may be prohibited under the MBTA.
According to the Information, Planning, and Conservation System (IPAC) Resource List for the Environmental Scan Area obtained from the USFWS website in July 2017, twenty-two species of
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4. AFFECTED ENVIRONMENT ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT migratory birds (including several species of grassland song birds) could potentially occur at or near the Ennis Big Sky Airport. The complete IPAC Resource List can be found in Appendix D.
As noted earlier, the Madison Valley IBA exists along the Madison River about 3 miles west of the Airport. The IBA was established in 2006 and contains riparian cottonwoods and willows along the Madison River surrounded by shortgrass prairie. The IBA Program has an initiative to identify, monitor, and protect a network of sites critical for the conservation of birds. Montana Audubon administers the program in Montana.
Eagles The bald eagle, listed under the Endangered Species Act (ESA) of 1973, as amended, has recovered in Montana and was officially delisted in 2007. Although no longer protected under the ESA, the species remains protected under the Bald and Golden Eagle Protection Act and the MBTA. While there is no formal process or requirement for consultation with the USFWS under the Bald and Golden Eagle Protection Act, agencies and others are encouraged to follow the National Bald Eagle Management Guidelines and the Montana Bald Eagle Management Guidelines: An Addendum to Montana Bald Eagle Management Plan, 1994. The Guidelines advise landowners, land managers and others who share public and private lands with bald eagles when and under what circumstances the protective provisions of the Act may apply to their activities. The Montana Guidelines should be followed to help prevent the disturbance of nesting eagles in the area.
According to the IPAC Resource List, bald eagles and golden eagles are among several raptor species that may occur near the Ennis Big Sky Airport. Bald eagles are known to use habitat along the nearby Madison River in search of open water for food supplies. An alternative food source during winter months include carrion left along US Highway 287 (located 1.5 miles west of the Airport). Several known nest sites exist west of the Airport along the Madison River, but there are no known nests within a mile of the project. Threatened, Endangered, Proposed, and Candidate Species The ESA protects listed threatened, endangered, proposed, and candidate plant and animal species and their critical habitats. The purpose of the ESA is to protect and recover imperiled species and the ecosystems upon which they depend.
A species listed as "endangered" is one that is in danger of extinction throughout all or a significant portion of its range. A "threatened" species is one that is likely to become endangered within the foreseeable future throughout all or a significant portion of its range. Proposed species are those species that are proposed in the Federal Register to be listed under the ESA. Candidate species are species for which the USFWS has sufficient information on biological status and threats to propose to list them as threatened or endangered. Under the ESA, critical habitat is defined as a specific geographic area that is essential for the conservation of a threatened or endangered species and that may require special management considerations or protection.
A review of the USFWS’ Montana Ecological Field Office website was conducted in December 2017 to initially identify protected species and critical habitat in Madison County. This review showed the following species occur within Madison County according to the agency’s November 17, 2017 Endangered, Threatened, Proposed and Candidate Species for Montana Counties list:
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Ute ladies’ tresses (Spiranthes diluvialis: Threatened) Canada lynx (Lynx Canadensis: Threatened) Red knot (Calidris canutus rufa: Threatened) Wolverine (Gulo gulo luscus: Proposed) Whitebark pine (Pinus albicaulis: Candidate).
The USFWS’s October 23, 2018 Endangered, Threatened, Proposed and Candidate Species for Montana Counties list includes the Grizzly bear (Ursos arctos horribilis) as Threatened species in Madison County. The USFWS issued a final rule delisting the Greater Yellowstone Ecosystem (GYE) grizzly bear Distinct Population Segment (DPS) on June 30, 2017 so the species did not appear on the November 17, 2017 ESA list for Madison County. A U.S. District Court Judge ruling restored ESA protection for the Yellowstone Grizzly bear population on September 24, 2018. This action vacated the 2017 final delisting rule for grizzly bears. On July 31, 2019, the USFWS issued a final rule listing all grizzly bears in the GYE as threatened under the ESA. Because the Court vacated the entire 2017 delisting rule, all grizzly bears in the lower 48 States are again listed as threatened.
There is no federally designated critical habitat in Madison County for any currently listed species.
Each listed species in Madison County, their preferred habitats, and the likelihood of the species occurring on or near EKS is discussed below.
Ute Ladies’ Tresses Ute ladies’ tresses occurs in alkaline wetlands, swales, and old meander channels often on the edge of the wetland or in areas that are dry by midsummer. Habitat is limited to areas within major river drainages [MTNHP, 2016b]. Potential habitat for the species occurs about 4 miles west of the project area along the Madison River. Because of the nature of the project area (i.e., heavily grazed and routinely mowed) and its distance from the Madison River drainage, the Ute ladies’ tresses is unlikely to be found within the project area.
Canada Lynx The Canada lynx is an elusive forest-dwelling cat of northern latitudes. The Canada lynx are closely associated with moist, cool, boreal spruce-fir forests, and landscapes with high densities of snowshoe hares. Suitable habitat includes subalpine forests at elevations ranging between 4,000 and 7,000 feet above sea level. Lynx also need persistent deep, powdery snow, which limits competition from other predators. Canada lynx may occur as rare transients in the general area. However, since the lands in and around the project area lack the type of habitat preferred by the species, Canada lynx would not be expected to occur at the Airport.
Red Knot The red knot is a small shorebird that migrates through Montana. The red knot relies on a limited number of important sites to stop, rest, and feed during its 18,000-mile migration route along an overland flyway across the mid-continental US including Montana. In Montana, lakes and other large wetlands, especially those resources rich with invertebrate prey, provide essential habitat for the red knot. The State of Montana considers this shorebird as a long-distance migrant with accidental or irregular stopovers; thus, not a suitable target for conservation activities. One
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4. AFFECTED ENVIRONMENT ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT migratory red knot occurrence at Ennis Lake (located about 9.5 miles north of the Airport) was recorded several decades ago. Red knots are not expected to occur at EKS because airport lands do not provide the shoreline and wetland habitats used as stopovers by the species.
Wolverine In North America, wolverines occur within a wide variety of habitats, primarily high elevation boreal forests, tundra, and western mountains throughout Alaska and Canada; however, the southern portion of the range extends into the contiguous United States, including Montana. South of the Canadian border, wolverines are restricted to areas in high mountains, near the tree-line, where conditions are cold year-round and snow cover persists well into the month of May. When inactive, wolverines occupy dens in caves, rock crevices, under fallen trees, in thickets, or similar sites. Wolverines are unlikely to occur because the type of habitat used the species does not occur on airport lands. The species may occur as rare transients in the general area.
Whitebark Pine Whitebark pine is a non-commercial conifer occurring primarily on federally owned or managed lands in the United States. Whitebark pine is typically found in cold, windy, high elevation or high latitude sites in western North America and as a result, many stands are geographically isolated. Based on the absence of suitable habitat characteristics (sub-alpine environment), whitebark pines do not occur in the immediate vicinity of the Ennis Big Sky Airport.
Grizzly Bear In Montana, grizzly bears primarily use meadows, seeps, riparian zones, mixed shrub fields, closed timber, open timber, sidehill parks, snow chutes, and alpine slabrock habitats. Habitat use is highly variable between areas, seasons, local populations, and individuals. The airport property does not include habitat components typically used by grizzly bears. However, suitable habitat exists within the Beaverhead-Deerlodge National Forest located about 2.5 miles east of the Airport and it is possible grizzly bears may occasionally be seen in the general project area. Montana Species of Concern Species of concern are native Montana animals or plants that are considered to be "at risk" due to declining population trends, threats to their habitats, and/or restricted distribution. Species of concern also include those for which current, often limited, information suggests potential vulnerability and other “special status” species which have some legal protections in place but are not recognized as species of concern in the state. Designation of a species as a Montana Species of Concern is not a statutory or regulatory classification.
The MNHP was contacted in September 2017 to conduct a file search for occurrences of species of concern on the sections of land containing the airport property and a one-mile buffer on all sides. MNHP’s database search of this 12-square-mile area identified occurrences of five animal species of concern—ferruginous hawk (Buteo regalis), Townsend's Big-eared Bat (Corynorhinus townsendii), Great Blue Heron (Ardea herodias), grizzly bear (Ursus arctos), and wolverine (Gulo gulo).
While these species exist in the area, the occurrence map provided by MNHP does not show any occurrences of these species on or immediately adjacent to lands that comprise the Ennis Big Sky
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Airport. A roost site for the Townsend’s big-eared bat has been documented approximately 1.6 miles east of the project area in the foothills of the Beaverhead-Deerlodge National Forest. Bats may forage for insects in the project area, however, airport lands lack suitable roost sites. 4.8 Hazardous Materials, Solid Waste, and Pollution Prevention Hazardous Materials Hazardous materials are products or wastes regulated by the EPA or the MDEQ. These include substances regulated under the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA or Superfund), the Resource Conservation and Recovery Act (RCRA), and regulations for solid waste management, above-ground storage tanks (ASTs) and underground storage tanks (USTs).
Existing databases for hazardous waste sites, generators, and remediation activities maintained by the EPA and the MDEQ were reviewed to help identify the potential for encountering hazardous wastes, substances, or materials at the Airport and on surrounding lands.
The EPA’s listing of Superfund sites does not include any sites in Madison County.
A review of the EPA’s online RCRAInfo search site shows no RCRA permitted facilities for treating, storing, or disposing of hazardous waste exist in Madison County. MDEQ’s online mapping website (available at http://svc.mt.gov/deq/wmadst/) did not identify any USTs, leaking USTs, Petroleum Tank Release Compensation Fund (spill) sites, Remediation Response sites, or hazardous waste handlers at or near the Ennis Big Sky Airport.
Northern Industrial Hygiene, Inc. performed an inspection for asbestos and lead-based paint in November 2017 at two aircraft hangars being considered for demolition. Laboratory testing of materials samples taken from the structures did not detect asbestos or lead-based paint. A copy of the inspection results can be found in Appendix G. Solid Waste Construction, renovation, or demolition associated with the building or rehabilitating runways, taxiways, and other aviation-related facilities typically produces debris (i.e. dirt, concrete, asphalt, electrical components, etc.) that requires proper disposal.
Madison County provides its residents with waste disposal services and recycling opportunities. The County maintains a container site and compactor in Ennis. Container sites are open 24 hours per day and accept all types of household waste materials. The County also maintains a Class III landfill in the Ennis area located 2.5 miles east of Jeffers on Jack Creek Bench Road. The landfill is approximately 4 air miles from the Airport. The Ennis landfill operates on an appointment only basis from 9:00 a.m. to 4:00 p.m., except for holidays. The landfill accepts all inert items such as untreated wood waste, metal, appliances, tires, concrete unpainted with re-bar removed, and tree branches.
Although there is no recycling program in place at Ennis Big Sky Airport, the County and its airport tenants are voluntary participants in recycling efforts. Voluntary sorting of several classes of recyclables occurs and these materials are transported to recycling bins at local container sites as
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4. AFFECTED ENVIRONMENT ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT convenient. Deplaned material that has been previously sorted are also transported to nearby container sites at the local landfill. 4.9 Historical, Architectural, Archaeological, and Cultural Resources The National Historic Preservation Act (NHPA) of 1966, as amended (16 U.S.C. 470 et seq.) established the Advisory Council on Historic Preservation (ACHP) and the NRHP maintained by the Secretary of the Interior. Section 106 of the NHPA requires federal agencies to consider the effects of their undertaking on properties on or eligible for inclusion in the NRHP. Section 106 also requires consultation with the ACHP, the SHPO, and/or the Tribal Historic Preservation Officer (THPO) if there is a potential adverse effect to historic properties on or eligible for NRHP listing.
The NHPA and its implementing regulations require the identification and evaluation of significant historical resources that may be affected by a proposed project. It further requires that resources so identified be avoided, if possible, or when avoidance is not possible, that any adverse effects of the project on the resources be mitigated. Resources in the Project Area The Montana SHPO maintains a listing of historical properties included on the NRHP. The NRHP currently includes 19 properties in Madison County including individual buildings, historic districts, and other properties like historic ranches, historic bridges, and community features or natural landmarks. None of the NRHP-listed sites in Madison County are near the Ennis Big Sky Airport.
Metcalf Archaeological Consultants, Inc., a cultural resources consultant, conducted a cultural resource surveys for lands potentially affected by the proposed improvements at the Ennis Big Sky Airport in September 2016, November 2017, and June 2019. A portion of Tract 4-A which adjoins the airport has not been surveyed for cultural resources because permission to access the property could not be obtained from the landowner. Archaeologists visually observed lands within Tract 4-A that could be readily seen from the airport property and Tract 4-B in June 2019. No cultural materials were observed on Tract 4-A during the visual inspection.
Prior to conducting the on-site reviews, a cultural resource file search was requested from the Montana SHPO to identify any previously recorded cultural sites in vicinity of the Airport. The file search was conducted for Section 36 of Township 6 South, Range 1 West; Sections 19, 30, and 31 of Township 6 South, Range 1 East; and Section 6 of Township 7 South, Range 1 East. The SHPO file search identified one previously recorded site—a rock cairn—located along US Highway 287. The cairn is not located in the area affected by the proposed improvements at the Airport.
Two cultural sites were recorded as a result of the on-site reviews—the Granger Ditch (24MA2400) and isolated find IF-CML-01. The Granger Ditch consists of a low-volume ditch (excavated trench) that extends in a northerly direction from a point of diversion on the Madison River well south of the Airport. A portion of the ditch crosses the western portion of the airport property. The Granger Ditch dates to 1902 and has since irrigated significant acreage on the east side of the river near the small town of Cameron. The Granger Ditch was recommended as eligible for the NRHP.
Isolated find IF-CML-01 consists of two historic artifacts (remnants of an old bottle and enamel
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4. AFFECTED ENVIRONMENT ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT ware) and one prehistoric artifact (a basalt or dacite flake) discovered on the southeast side of the Ennis Big Sky Airport property. The isolated find was not recommended as eligible for the NRHP by the consulting archaeologists because the artifacts likely originated off the airport property. In an effort to determine the origin of the artifacts, a supplemental investigation of an adjoining portion of Tract 4-B was performed in June 2019. The supplemental investigation included an intensive pedestrian survey of the property, but no cultural materials were found on Tract 4-B. Therefore, the origins of the artifacts discovered on the airport remain undetermined.
The FAA agreed with the consulting archaeologists’ eligibility recommendations and forwarded the September 2016 cultural resources survey to the Montana SHPO on December 6, 2016. The FAA also made determinations of eligibility at that time. The Montana SHPO concurred with the determination that the Granger Ditch is eligible for listing in the NRHP and the Isolated find is not eligible for listing in the NRHP in correspondence on December 16, 2016. This determination for the Granger Ditch means that it is also a Section 4(f) resource as described in Section 4.5.
Copies of correspondence between the FAA and Montana SHPO can be found in Appendix A. The 2016 and 2017 cultural reports can be found in Appendix C. 4.10 Visual Effects (Including Light Emissions) The FAA considers the extent to which any lighting associated with an action would create an annoyance among people in the vicinity or interfere with their normal activities. The visual resources of an area include the features of its landforms, vegetation, water surfaces and cultural modifications (physical changes caused by human activities) that give the landscape its visually aesthetic qualities. Landscape features, natural appearing or otherwise, form the overall impression of an area.
Generally undeveloped areas such as national parks, national forest lands, and recreation or wilderness areas could be considered to have high visual sensitivity. Developed urban areas and commercial and industrial sites are areas of low visual sensitivity due to their altered landscapes. Light Emissions Airport facilities and operations cause light emissions that can affect visually sensitive land uses in an airport area. Runway lighting systems may create potential sources of annoyance to nearby residents in the vicinity if light is directed towards light-sensitive land uses. The intensity, color, or flashing sequence of airport lighting may also create an annoyance for people in the vicinity of the Airport. Sources of lighting at airports may include: airfield and apron lighting, visual navigational aids (NAVAIDS), terminal and hangar /building lighting, employee/customer parking lighting, security lighting, both airborne and ground-based aircraft operations, and roadway lighting along access roads.
The following light sources currently exist at the Ennis Big Sky Airport:
Medium Intensity Runway Lighting (MIRL) system along Runway 16/34; Medium Intensity Taxiway Lighting (MITL) at the entrance to each connecting taxiway; Lighted guidance signage; Precision Approach Path Indicators (PAPIs) at each end of Runway 16/34;
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A rotating beacon with clear and green lenses and obstruction lights in the terminal area; Lighted windcone with segmented circle; Obstruction lighting atop the automated weather observing system (AWOS); Security lighting at miscellaneous airport buildings and hangars; and Identification lights, strobe lights, and landing lights typically installed on aircraft. Visual Setting The visual resources of an area include the features of its landforms, vegetation, water surfaces and cultural modifications (physical changes caused by human activities) that give the landscape its visual character and aesthetic qualities. Landscape features, natural appearing or otherwise, form the overall impression of an area. Visual resources are typically assessed based on landscape character (what is seen), visual sensitivity (human preferences and values regarding what is seen), scenic integrity (degree of intactness and wholeness in landscape character), and landscape visibility (relative distance of seen areas) of a geographically defined view shed.
The Madison Valley elevation is approximately 5,000-feet above mean sea level, with several surrounding mountain ranges peaking at approximately 11,300-feet. The valley is bordered by the Centennial Range on the south, the Tobacco Root Range to the north, the Gravelly Range to the west, and the Madison Range to the east. The Madison, Beaverhead, Big Hole, Jefferson, and Ruby Rivers are all major rivers within Madison County. A variety of visual settings exist in the general vicinity of the Ennis Big Sky Airport including mountain peaks, foothills and open grassland areas, agricultural lands, corridors for local roads, and scattered rural residences.
The Ennis Big Sky Airport is situated in the broad Madison Valley with significant mountainous terrain existing several miles east of the Airport. The property immediately surrounding the Airport is used for agricultural purposes with scattered residences on subdivided lands. A notable concentration of hangars and other airport-related buildings exists west of Runway 16/34. 4.11 Natural Resources and Energy Supply Executive Order (EO) 13693, Planning for Federal Sustainability in the Next Decade (signed March 19, 2015), instructs federal agencies to increase efficiency and improve their environmental performance by reducing energy use and cost by finding renewable or alternative energy solutions. EO 13693 proposes to cut the Federal Government’s Greenhouse Gas (GHG) emissions 40% over the next decade from 2008 levels and increase the share of electricity the Federal Government consumes from renewable sources to 30%. In addition, EO 13693 outlines a number of measures to make the Federal Government’s operations more sustainable.
FAA policy encourages the development of facilities that exemplify the highest standards of design, including principles of sustainability. Additionally, the agency advocates that all elements of the transportation system should be designed with a view to their aesthetic impact and conservation of resources such as energy, pollution prevention, harmonization with the community environment, and sensitivity to the concerns of the traveling public.
The energy supply for the Ennis Big Sky Airport area consists of electricity supplied by NorthWestern Energy and propane is provided by numerous area suppliers. These energy resources are not in short supply in Madison County. Gasoline and diesel fuel typically power
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4. AFFECTED ENVIRONMENT ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT airport vehicles and equipment. Water and wastewater disposal for FBOs at Ennis Big Sky Airport is provided by individual wells and septic systems.
Natural resources and construction materials such as asphalt, concrete, and gravel are readily available in the Ennis area. 4.12 Climate
The Intergovernmental Panel on Climate Change (IPCC) estimates that aviation accounted for 4.1% percent of global transportation GHG emissions. In the United States, U.S. Environmental Protection Agency (EPA) data indicate that commercial aviation contributed 6.5% of total carbon dioxide (CO2) emissions in 2016, compared with other sources, including the remainder of the transportation sector (22.0%), industry (29.1%), commercial (16.3%), residential (15.4%), agricultural (10.0%) and U.S. territories (0.07%).3
Scientific research is ongoing to better understand climate change, including any incremental atmospheric impacts that may be caused by aviation. Uncertainties are too large to accurately predict the timing, magnitude, and location of aviation’s climate impacts; however, minimizing GHG emissions and identifying potential future impacts of climate change are important for a sustainable national airspace system.
Increasing concentrations of GHGs in the atmosphere affect global climate.4 GHG emissions result from anthropogenic sources including the combustion of fossil fuels. GHGs are defined as including carbon CO2, methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons 5 (PFCs), and sulfur hexafluoride (SF6). CO2 is the most important anthropogenic GHG because it is a long-lived gas that remains in the atmosphere for up to 100 years.
Climate change is a global phenomenon that can have local impacts. Research has shown there is a direct correlation between fuel combustion and GHG emissions.6 Scientific measurements show that Earth’s climate is warming, with concurrent impacts including warmer air temperatures, increased sea level rise, increased storm activity, and an increased intensity in precipitation events.
3 GHG allocation by economic sector. Environmental Protection Agency (2018). Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990‐2016. Available at: https://www.epa.gov/sites/production/files/2018-01/documents/2018_complete_report.pdf 4 IPCC (2014). Fifth Assessment Report. Available at: https://www.ipcc.ch/report/ar5/syr/ United States Global Change Research Program (2009). Global Climate Change Impacts in the United States. Available at: http://www.globalchange.gov/what-we-do/assessment/previous-assessments/global-climate-change- impacts-in-the-us-2009. 5 Executive Order 13693, Planning for Federal Sustainability in the Next Decade. Available at: https://obamawhitehouse.archives.gov/the-press-office/2015/03/19/executive-order-planning-federal- sustainability-next-decade. 6 As explained by the EPA, “greenhouse gases, once emitted, become well mixed in the atmosphere, meaning U.S. emissions can affect not only the U.S. population and environment but other regions of the world as well; likewise, emissions in other countries can affect the United States.” EPA, (2009) Climate Change Division, Office of Atmospheric Programs, Technical Support Document for Endangerment and Cause or Contribute Findings for Greenhouse Gases under Section 202(a) of the Clean Air Act 2‐3. Available at: http://www.epa.gov/climatechange/Downloads/endangerment/TSD_Endangerment.pdf.
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4.13 Noise and Compatible Land Use Noise Background and Terminology One of the primary conditions that residents near an airport express concern with is aircraft noise. For this evaluation, aircraft noise impacts are described in terms of the land area (including population and housing) exposed to aircraft noise above predetermined levels. Noise levels are quantified using units of decibels using the A-weighted scale (dBA). Humans typically have reduced hearing sensitivity at low frequencies compared with their response at high frequencies, and the A- weighting of noise levels closely correlates to the frequency response of normal human hearing.
On the A-weighted decibel scale, an increase of 10 dBA means that a sound is 10 times more intense, or powerful. Most people perceive a 10-dBA noise increase as being twice as loud as the original noise level. Most people would likely perceive a 5-dBA change in a given noise source under normal conditions if the general nature of the noise remained constant (for instance, minor increases in traffic noise).
As discussed in Chapter 11. Noise and Noise‐Compatible Land Use of the FAA’s Order 1050.1F Desk Reference, the FAA has determined the cumulative noise energy exposure of individuals to noise from aviation activities must be established in terms of DNL. The FAA requires the DNL metric for airport environmental studies because it uses a single number to describe the constantly fluctuating noise levels at a receiver location during an average annual 24-hour day. The DNL includes a 10-dBA penalty that is added to noises that occur during the nighttime hours between 10:00 p.m. and 7:00 a.m., to account for people’s higher sensitivity to noise at night when the background noise level is typically lower. The ambient noise levels are far less during these quiet times, therefore, noise of any kind is perceived as being louder, even though it may not be the case. Noise Modeling for EKS With the adoption of 14 CFR Part 150, Airport Noise Compatibility Planning, the FAA established that noise contour maps would be used as a planning tool to determine if land located near airports is compatible with the operation of the airport, and to determine if noise-sensitive locations near airports would be negatively impacted by changes to an airport or its operations.
Noise modeling is accomplished using specialized computer software which consider the operational modes and characteristics of many aircraft types, relationships between the noise source and receiver, and other environmental factors. FAA guidance notes that the Aviation Environmental Design Tool (AEDT) must be used. AEDT models a flight, taking into account the aircraft weight and performance characteristics and weather conditions, and calculates the resulting noise. Airport noise contours are normally presented in terms of DNL noise contour maps commonly showing contours for 65, 70, and 75 dBA.
BridgeNet International (BridgeNet), an airport air and noise emissions consultant, was retained in late 2017 to conduct noise modeling and prepare noise contours for EKS. As required by the FAA’s September 9, 2016 guidance, BridgeNet used AEDT Version 2d (current version) to perform the noise modeling based on current and projected future annual aircraft operations and aircraft fleet characteristics at EKS. The modeling effort was used to help identify existing noise levels at EKS and to determine the potential noise-related effects of airport improvement alternatives.
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Appendix F documents the noise and emissions modeling assumptions associated with preparing the noise contours used in this section. Key assumptions for the development of the existing (2015) noise contours for EKS are listed below7:
In 2015, average annual aircraft operations were estimated to be 12,200.
o Approximately 90% of the operations were single engine aircraft operations (10,924 operations by single engine and 34 by single turbo engine aircraft). Such single engine aircraft include the Piper Malibu Meridian, SR22, and Cessna Skylane 182.
o Approximately 4% of the annual operations were by business jets (513 operations annually). The dominant business jets seen at EKS include Dassault Falcon 2000, Cessna Excel 560, and Cessna Citation 680.
o Approximately 6% of the annual operations were by twin engine aircraft, that were modeled in the AEDT noise model as the Dash 6.
Approximately 70% of the arrivals to the Airport approach the runway from the 16 end (north end) and 30% approach from the 34 end (south end). Most departures are from north to south due to prevailing winds and direction of origin/destination airports.
Aircraft operating from EKS typically fly less than 500 nautical miles, and thus, the Stage Length used in AEDT was Stage Length 1 (0-500 nautical miles), which is the stage lengths available for modeling for these aircraft types in the AEDT noise model. Existing Noise Exposure Contours The existing noise exposure contours for Ennis Big Sky Airport are shown on Figure 4‐4. The figure shows contours for DNL 65 dB, DNL 70 dB and DNL 75 db. These noise contours are an average annual depiction of aviation-related noise considering the present layout of the Airport and aircraft types currently using the facility. The use of DNL contours is meant to provide a general indication of impact and is not intended to determine the reaction of people due to individual events, such as a single take-off or landing.
The area exposed to noise levels above DNL 65 dB and greater sound levels are of interest for airports. This is because the FAA’s guidelines show that residential areas and other noise-sensitive land uses are normally incompatible in areas where noise levels above DNL 65 dB occur. There are about 147 acres of land within the DNL 65 dB noise contour based on current aviation operations. The DNL 65 dB noise exposure contour for Runway 16/34 extends beyond the existing airport property at some locations; however, the area encompassed by the DNL 65 dB noise contour outside the airport property includes agricultural lands at the north and south ends of the runway and undeveloped 10-acre or less residential tracts east and west of the Airport. There are no residences or other noise sensitive land uses within the existing DNL 65 dB contour.
7 The year 2015 was selected to represent “existing” conditions to ensure consistency between AEDT air and noise emissions modeling and the operational baseline for aircraft operations and fleet mix established in the 2018 Ennis Big Sky Airport Master Plan Update.
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Figure 4-4: Noise Contours for the Existing Airport (2015 Baseline Conditions)
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4.14 Socioeconomics, Environmental Justice, and Children’s Environmental Health and Safety Risks Title VI of the US Civil Rights Act of 1964, as amended, EO 12898, Federal Actions to Address Environmental Justice in Minority Populations and Low‐Income Populations and Order DOT 5610.2, Environmental Justice require that no minority, or, by extension, low-income person shall be disproportionately adversely impacted by any project receiving federal funds. For transportation projects, this means that no particular minority or low-income person may be disproportionately isolated, displaced, or otherwise subjected to adverse effects. Potential impacts are assessed in terms of property acquisitions or relocations, changes in access to employment areas, and other changes in low-income and minority communities/neighborhoods. To determine whether an environmental justice population is present, Federal agencies must refer to U.S Census data to establish the demographic and socio-economic baseline.
DOT Order 5610.2 defines minorities as Black, Hispanic, Asian-American, American Indian and Alaskan Native, and Native Hawaiians and Other Pacific Islander individuals. The order also identifies low income individuals as a person having a median household income at or below the Department of Health and Human Services’ (HHS) poverty guidelines. The Census Bureau’s annual statistical poverty thresholds on income and poverty are typically used to define low income. EO 13045, Protection of Children from Environmental Health Risks and Safety Risks, requires Federal agencies to identify disproportionately high and adverse impacts to children. Demographic Baseline
Permanent Population Historical population data from U.S. Census for the State of Montana, Madison County, and the Town of Ennis over the 1960 to 2010 period is shown in Table 4.2. Although a small decrease in population was recorded during the 1960s, Madison County has shown consistent growth in its population every decade since 1970. The County saw its total population grow by 8.7% over the 1970 to 1980 period, by 9.9% between 1980 and 1990, by 14.4% in the 1990s, and by 12.3% between 2000 and 2010. Except for the 1960-1970 period, the average annual growth rates in the decades between 1970 and 2010 varied from a low of about 0.83% (1970-1980) to a high of more than 1.4% (1990-2000). The annual growth rate averaged 0.78% per year over the 1960-2010 period.
The population of the Town of Ennis remained relatively stable at about 500 residents during the 1960s; however, the Town has grown steadily after 1970. The Town’s population increased by more than 31% between 1970 and 1980 and by almost 19% during the 1990s. The Town’s population has remained fairly stable at around 840 residents since 2000.
The Montana Census and Economic Information Center periodically releases mid-year population estimates for counties and incorporated communities within each county. These estimates place the “current” populations of Madison County and the Town of Ennis at 7,924 (2016 estimate) and 884 residents (2015 estimate), respectively. Using these estimates, Madison County’s population grew by about 3.0% over the 2000-2016 period while the State’s population grew by 5.4% over the
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Table 4.2: Historical Populations – State of Montana, Madison County, and Ennis
State of % Change Madison % Change Town of % Change Year Montana by Decade County by Decade Ennis by Decade 1960 674,767 -- 5,211 -- 525 -- 1970 694,409 2.9% 5,014 -3.8% 501 -4.6% 1980 786,690 13.2% 5,448 8.7% 660 31.7% 1990 799,065 1.6% 5,989 9.9% 785 18.9% 2000 902,195 12.9% 6,851 14.4% 840 7.0% 2010 989,415 9.7% 7,691 12.3% 838 -0.2% 2015*/2016** 1,042,520** -- 7,924** -- 884* -- Source: U.S. Census Bureau * Total Population, Montana Incorporated Cities & Towns by County, 1990 – 2015; Montana Department of Commerce, Census and Economic Information Center (Released May 2016); Available at: http://ceic.mt.gov/Documents/PopulationProjections/Census_PopEstimates_IncCitiesTownsByCounty_Montana_1990-2015.xlsx ** Montana County Total Population Estimates, US Census Bureau, Population Division - Released March 2017; Available at: http://ceic.mt.gov/Documents/PopulationProjections/Census_PopEstimates_CountyPopulation_Montana_2010_2016.xlsx.
Seasonal Population A variety of data sources suggest that seasonal residents will continue to play a significant role in Madison County’s growth and development pattern. The 2000 Census described 67% of the vacant housing stock in Madison County as seasonal or recreational; in 2010 approximately 86% of the vacant housing was seasonal or recreational. According to the 2010 Census, about 76% of all the vacant housing units for seasonal, recreational, or occasional use (2,199 housing units) were located in the Madison Valley County Census Division; which includes the Ennis area, adjoining lands in the Madison Valley south of Ennis, and a portion of the Big Sky-Moonlight Basin area. As further evidence of the high seasonal population, the Madison County Growth Policy 2012 indicates “about 63% of Madison County’s private properties list a permanent address outside of Madison County.”
The seasonal, recreational, or occasional use housing units, within the Madison Valley, has seen an average annual increase of 11.3% over the period of 2000-2010. Economy and Employment The economy of Madison County is driven by ranching, farming, construction, limited mining, and tourism/recreation. Two large ski resort areas, Big Sky and Moonlight Basin, lie either entirely or partially within Madison County and are large employers. The Big Sky area has grown substantially in recent years, and the new development has increased service-related businesses and tax revenues. The Madison, Beaverhead, Big Hole, Jefferson, and Ruby Rivers are popular fishing and recreation destinations. Upland bird, migratory waterfowl, and big game hunting are major attractions in the fall. These recreational pursuits help support associated service industries within the county.
Table 4.3 presents data on the estimated number of civilian employees (age 16 years and older) and the industries in which they are employed in the State of Montana, Madison County and the Town of Ennis. The data in the table, taken from 2012-2016 American Community Survey (ACS)
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4. AFFECTED ENVIRONMENT ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT profile for these geographies, also includes employment estimates by industry. As the table shows, the employed population in Madison County for the 5-year period is estimated at 3,890 with about 14% of the employed persons in the county being residents of the Town of Ennis.
Table 4.3: Civilian Employment by Industry (2012-2016)
STATE OF MADISON TOWN OF INDUSTRY MONTANA COUNTY ENNIS Agriculture, forestry, fishing, hunting, and mining 34,822 7.1% 753 19.4% 19 3.5% Construction 40,566 8.3% 360 9.3% 93 17.0% Manufacturing 22,275 4.5% 99 2.5% -- -- Wholesale Trade 11,542 2.4% 36 0.9% 13 2.4 Retail Trade 58,432 11.9% 342 8.8% 41 5.5% Transportation, warehousing, and public utilities 23,614 4.8% 206 5.3% 30 2.4% Information 8,618 1.8% 55 1.4% 13 2.6% Finance and Insurance, and real estate and rental and 26,795 5.5% 125 3.2% 14 15.7% leasing Professional, scientific, management and 40,620 8.3% 289 7.4% 86 10.2% administrative Education services, health care, and social assistance 114,529 23.3% 637 16.4% 96 17.6% Arts, entertainment, and recreation, and 54,238 11.1% 638 16.4% 102 18.6% accommodation, and food services Other services, except public administration 23,617 4.8% 147 3.8% 27 4.9% Public administration 31,074 6.3% 203 5.2% 13 2.4% Total Employed Population 16 years 490,742 3,890 547 of age and older Source: U.S. Bureau of the Census, American Community Survey (ACS) Profile Report: 2012-2016 (5-year estimates), available at: http://census.missouri.edu/acs/profiles/
The majority of the employment in the county and Town of Ennis is associated with agriculture forestry and mining; construction; education; health care and social assistance; the service industries; retail trade; and professional, management and administrative occupations.
The Montana Department of Labor and Industry, Research and Analysis Bureau8 lists the top private employers in Madison County during 2016 as being:
Big Sky Resort (500 to 999 employees); Yellowstone Club (250-499 employees); A. M. Welles Inc. (50-99 employees); Madison Valley Hospital (50-99 employees); Ruby Valley Hospital (50-99 employees); and 5 other businesses with 20 to 49 employees.
8 "Montana Labor Market Information." http://lmi.mt.gov/ . Montana Department of Labor and Industry, 2018
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As of February 2018, the Department of Labor and Industry statistics show non-seasonally adjusted unemployment rates of 4.4% for Montana as a whole and 5.0% for Madison County. This compares with a non-seasonally adjusted unemployment rate of 4.4% for the entire U.S. Socio-Economic Baseline Several socio-economic characteristics of the populations for the United States, State of Montana, Madison County, County Census Tract 1 (which encompasses the Airport) and the Town of Ennis are presented below.
Table 4.4 shows information from the American Community Survey (ACS) Profile Report: 2012‐2016 about the race and ethnicity characteristics in geographic areas of interest for this project. It is apparent from the data that minority populations in Madison County and Ennis are well below corresponding minority populations for the State of Montana and the U.S.
Table 4.4: Race and Ethnicity – U.S., State of Montana, Madison County, and Ennis
County Race/Ethnicity United States State of Madison Census Town of Montana County Tract 1 Ennis White 73.3% 89.1% 95.7% 96.6% 96.7% Black or African American 12.6% 0.4% 0.4% 0.4% -- American Indian and Alaska Native 0.8% 6.6% 0.5% 0.5% 0.6% Asian 5.2% 0.7% 0.2% -- -- Native Hawaiian and Other Pacific 0.2% 0.1% ------Islander Some Other Race 4.8% 0.5% 1.3% -- -- Two or More Races 3.1% 2.6% 2.0% 2.5% 2.7% Hispanic or Latino (of any race) 17.3% 3.4% 3.0% 1.3% -- Total Population 318,558,176 1,023,391 7,810 3,213 931 Minority Population* 36.1% 11.2% 4.1% 2.2% 0.6% Source: U.S. Census Bureau, American Community Survey (ACS) Profile Report: 2012-2016, Selected SocioEconomic Characteristics * Based on DOT Order 5610.2 definition of minority
Several statistics commonly used to define income characteristics of residents in Madison County and the Ennis area are presented in Table 4.5.
According to the ACS Profile Report: 2012‐2016 estimates, median household income levels for Madison County residents were generally below those for the State of Montana as a whole and the nation. Median household income for residents of Census Tract 1 exceeded those seen for the State of Montana and the County. Median household income levels for residents of the Town of Ennis were about 10% lower than those for all County residents. Per capita income levels for Madison County residents track closely with those for the State of Montana with residents of Census Tract 1 showing per capita incomes about 19% higher than the Statewide average. Per capita income levels for residents of the Town of Ennis were near the Statewide average but lower than those of all County residents and the nation. The 2012-2016 ACS data also shows the percentage of Madison County residents living below the poverty level was less than seen for the State of Montana and the nation.
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Table 4.5: Selected Income Measures - State of Montana, Madison County, and Ennis
Income Measures Median Per Capita Percentage of Persons Jurisdiction Household Income Income Below Poverty Level United States $55,322 $29,829 15.1 State of Montana $48,380 $27,309 14.9 Madison County $47,617 $30,030 11.3 County Census Tract 1 $48,333 $32,539 11.3 Town of Ennis $42,917 $29,106 3.7 Source: U.S. Census Bureau, American Community Survey (ACS) Profile Report: 2012-2016, Selected Socio- Economic Characteristics
Table 4.6 provides other socio-economic characteristics of Madison County and Ennis area residents. The data in the table shows median ages of residents of Madison County and Ennis are notably older than that seen for all residents of the State of Montana or the nation. Madison County also has a higher percentage of elderly residents (age 65 and over) than seen in the State of Montana’s population or the nation. The percentage of all Madison County residents living with a disability was like that seen for that State and nation; however, the Town of Ennis had a slightly higher percentage of residents with disabilities than seen for the entire county.
Table 4.6: Miscellaneous Socio-Economic Characteristics – U.S., State of Montana, Madison County, and Ennis Area
County United State of Madison Census Town of Characteristic States Montana County Tract 1 Ennis Median Age 37.7 39.8 52.1 53.1 42.4 Population age 65 and 14.5 16.7 26.1 29.6 24.1 over (Percent) Persons with disability 12.5 13.5 12.4 10.1 14.7 Average household size 2.64 2.41 2.24 2.04 2.57 Born in state of current 68.7 56.3 45.4 35.6 39.3 residence (Percent) Median home value $184,700 $199,700 $240,300 $325,900 $194,800 Source: U.S. Census Bureau, American Community Survey (ACS) Profile Report: 2012-2016, Selected Socio- Economic Characteristics
The ACS data presented in Table 4.6 suggests the average household size in Madison County is lower than that seen for all residents of Montana and the nation. Median home values in the County are substantially higher than the Statewide or national average. Significant areas of recreational and seasonal home development at the Big Sky and Moonlight Basin resorts are responsible for the high median home values seen in Census Tract 1 of Madison County. Statistics also show the population of Madison County is comprised of fewer native-borne Montanans than seen for the State as a whole. These trends may be attributed in part to the natural amenities and recreational opportunities found in the area which attract retirees and others with the economic means to establish homes in Madison County.
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A review of the ACS information presented above does not indicate the presence of either minority or low-income populations residing in the immediate area of the Airport.
There are no Native American Reservations close to Ennis Big Sky Airport.
There are no hospitals, assisted living facilities, or churches within 1-mile of the Ennis Big Sky Airport, and none are known to be planned within the general area. Children’s Environmental Health and Safety Risks There are no other known schools, daycare facilities, playgrounds, or other places where children are concentrated within the immediate vicinity of Ennis Big Sky Airport. 4.15 Water Resources The Clean Water Act (CWA), the Federal Water Pollution Control Act, and the Safe Drinking Water Act establish the federal government’s authority to protect water quality. Water quality impacts that must be considered include actions that might impair water quality or quantity to surface waters, groundwater, or drinking water supplies. Surface Water Resources The project area lies within the Madison River Valley and surface waters originate in the Madison Range located east of the Airport. Surface water resources on and adjacent to the Airport were identified through an off-site review of existing information and a field investigation by an environmental resource consultant. Four intermittent (or ephemeral) drainages and an irrigation ditch pass through the project area. These surface water features include:
McDeed Creek; Boulder Creek and two unnamed tributaries; and Granger Ditch.
Figure 4‐5 shows surface water resources in the vicinity of EKS.
McDeed Creek is an intermittent stream channel that supports fringe wetlands. Seasonal surface flow typically only occurs during snowmelt in this watershed. The McDeed Creek channel ranges from 1-foot-wide (east of the runway) to 3.5-feet-wide (west of the runway). McDeed Creek is a tributary to Bear Creek (located west of US Highway 287) which joins O’Dell Spring Creek east of Ennis. The 2008 project at EKS installed culverts for McDeed Creek beneath the runway and parallel taxiway area at the “16” end of the runway. Additionally, a channel change of about 1,370 feet in length was constructed along a portion of McDeed Creek in 2008.
Boulder Creek, which includes Shell Creek upstream from the project area, flows intermittently and primarily during snowmelt and substantial rain events. Boulder Creek is a tributary to Bear Creek. This drainage feature lacks a bed or banks through most of the project area and consists of an upland (non-wetland) vegetated swale. Culverts have been installed beneath the runway and parallel taxiway to maintain flows in Boulder Creek.
The northernmost unnamed tributary to Boulder Creek is a 3-foot to 4-foot-wide rock-lined channel paralleling Waco Lane that has been straightened through the project area and higher in the
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4. AFFECTED ENVIRONMENT ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT watershed. Surface flow is seasonal and typically only occurs during snowmelt. Localized flooding can occasionally occur during spring snowmelt as this drainage crosses the airport property. The other unnamed tributary exhibits bed and banks along some areas while other reaches consist of a non-wetland vegetated swale. This drainage rarely exhibits flow. This channel has been highly manipulated and rerouted over the years. The unnamed tributaries of Boulder Creek, like McDeed and Boulder Creeks, do not provide adequate habitat for a viable fishery resource. Culverts have been installed beneath the runway and parallel taxiway to accommodate flows in both unnamed tributaries to Boulder Creek.
The Granger Ditch is a man-made irrigation facility that originates in Bear Creek nearly 12 miles south of the project area and appears to terminate close to the northern end of the project area. The banks of the ditch are stable and well vegetated with a variety of upland grassland species. The ditch does not contain wetlands or provide habitat for fish or other animal aquatic species.
Figure 4-5: Surface Waters Near the Airport
Unnamed Tributaries McDeed to Boulder Creek
Creek Ennis Big Sky Airport
Surface Water Quality
The MDEQ has the responsibility under Section 401 of the CWA and the Montana Water Quality Act to monitor and assess the quality of Montana surface waters and to identify impaired or threatened
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4. AFFECTED ENVIRONMENT ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT stream segments and lakes. The MDEQ sets limits, known as Total Maximum Daily Loads (TMDLs), for each pollutant entering a body of water. TMDLs are established for streams or lakes that fail to meet certain standards for water quality and describe the amount of each pollutant a water body can receive without violating water quality standards.
The project area lies within the Madison TMDL Planning Area (TPA). The Madison TPA includes the Madison River and its major tributaries (from the South Fork of the Madison near Yellowstone National Park to the confluence with the Missouri River near Three Forks).
Section 303(d) of the CWA requires states to identify waters where quality is impaired or threatened. McDeed Creek and Boulder Creek are not on the 2016 303(d) list; however, Bear Creek is listed as an impaired waterbody because it does not fully support aquatic life. MDEQ has identified siltation/sedimentation as the primary cause of water quality impairment in Bear Creek. Floodplains
To comply with Executive Order No. 11988 Floodplains and the U.S. Department of Transportation (DOT) Order 5650.2, Floodplain Management and Protection, all airport development actions must avoid the floodplain, if a practicable alternative exists. To accomplish this, the Proposed Action must be evaluated to determine the effects of any encroachments on the “base” floodplain. The base floodplain is the area covered by water from the 100-year flood. The 100-year flood represents a flood event that has a 1 percent chance of being equaled or exceeded in any given year. Proposed actions in a floodplain must be designed to minimize adverse impact to the floodplain’s natural and beneficial values. The design must also minimize the potential risks for flood-related property loss and impacts on human safety, health, and welfare.
The Federal Emergency Management Agency (FEMA) routinely prepares detailed Flood Insurance Rate Maps (FIRMs) for flood prone and flood hazard areas. A review of FEMA’s website shows the agency has not produced a FIRM for the area that includes Ennis Big Sky Airport and there are no FEMA-designated floodplains or flood hazard areas in the project area.
The Madison County Board of Commissioners adopted the Madison County Floodplain Hazard Management Regulations in April 2017 to regulate activities in designated flood hazard areas. The County’s regulations apply to FEMA-regulated floodplains and Flood Hazard Areas as well as other “flood prone areas” in the County. A flood prone area is defined in the regulations as an area having potential to be located in 100-year floodplain as designated on USGS maps dated March 10, 1997 produced by Madison County or on adopted floodplain maps.
Madison County’s mapping of flood prone areas can be found online at: http://madisoncountymt.gov/311/Flood-Prone-Maps.
The Ennis Flood Prone Map (dated March 10, 1997) shows three named streams located on or near the Airport—McDeed Creek, Shell Creek, and Boulder Creek. However, no flood prone areas are shown along these streams. The nearest County-designated flood prone area is along the Madison River located about 3.5 miles west of the Airport.
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Based on this review, this project would not affect any FEMA-designated floodplains or flood hazard areas or County-designated flood prone areas. Groundwater The project area is located at the south edge of the Cedar Creek Alluvial Fan which was created by Tertiary age sediments from the erosion of nearby mountains in the Madison Range. These sediments consist of deposits of sandstone, volcanic ash, and unconsolidated mixtures of sand, gravel, silt and clay. The thickness of the deposits typically varies but can range from 300 to 500 feet near the south edge of the Cedar Creek Alluvial Fan. In general, these sediments supply good quality ground water to many of the shallow wells (less than 200 feet) in the Madison Valley. Alluvial deposits along terrace, outwash fans, and floodplain also represent an important source of ground water for domestic and stock watering purposes.
Records of wells maintained by the Groundwater Information Center (GWIC) at the Montana Bureau of Mines and Geology show more than 20 wells in the general vicinity of the Airport. Static water levels at wells in the area generally exceed 120 feet.9 Wetlands The CWA and Executive Order 11990, Protection of Wetlands, establish the federal government’s authority over activities that occur within wetlands. Federal agencies must ensure their actions minimize the destruction, loss, or degradation of wetlands. These regulations also assure the protection, preservation, and enhancement of the Nation’s wetlands to the fullest extent practicable.
The EPA and the U.S. Army Corps of Engineers (COE) use the following definition of wetlands for regulatory purposes:
“Those areas that are inundated or saturated by surface or ground water (hydrology) at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation (hydrophytes) typically adapted for life in saturated soil conditions (hydric soils).” (40 CFR 232.2(r)).
Jurisdictional wetlands—those that are regulated by the COE under Section 404 of the CWA—must exhibit all three of the characteristics referred to in the definition. Jurisdictional determinations are provided by the COE for implementation of Section 404 of the CWA. Jurisdictional wetlands and waterways are identified as areas that maintain a surface hydrological connection with known “waters of the U.S.” Waters of the U.S. include the area below the ordinary highwater mark (OHWM) of stream channels and lakes or ponds connected to the tributary system, and wetlands adjacent to these waters. Non-jurisdictional wetlands are isolated due to a lack of an apparent hydrologic connection to waters of the U.S. Final jurisdictional status for all delineated wetlands and waters within a project area must be provided by COE.
9 Montana Bureau of Mines and Geology, Groundwater Information Center website, available at: http://data.mbmg.mtech.edu/mapper/mapper.asp?view=Wells&; Accessed: November 2017.
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4. AFFECTED ENVIRONMENT ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT
Wetland Identification A wetland delineation of the Ennis Big Sky Airport property and adjacent areas potentially affected by airport improvements was completed by a wetland specialist in September 2016. Relevant published information and maps were reviewed initially to help identify potential wetland areas and non-wetland waterways within the project area. A wetland specialist visited the project area to identify jurisdictional wetlands and other “waters of the U.S.” that could potentially be affected during project development.
The wetland delineation was conducted in accordance with the 1987 Corps of Engineers Wetlands Delineation Manual [Environmental Laboratory, 1987] and the Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountains, Valleys, and Coast Region (Version 2.0) [US Army Corps of Engineers, 2010]. Vegetation, hydrology, and soils were examined and data representing upland and wetland areas were recorded onto COE Wetland Determination Data Forms. Each delineated wetland was classified using the USFWS’s Classification of Wetlands and Deepwater Habitats of the United States (Cowardin et al. 1979).
Wetland Sites One wetland site (WL-01) was identified and delineated along the McDeed Creek and its associated “fringe.” Wetland hydrology is primarily supplied during spring runoff. The wetland is classified as a palustrine emergent (PEM) wetland. WL-01 is dominated by species that normally remain standing, at least until the beginning of the next growing season. Dominant hydrophytic vegetation includes creeping bentgrass, Baltic rush, and long-styled rush.
Data about the wetland were recorded on the Wetland Determination Data Forms characterizing the typical wetland and upland conditions observed at each sample point location. Vegetation, soils, and hydrology were examined in many additional sampling locations to accurately delineate the wetland boundary. Note that the wetland boundary extends both upslope and downslope beyond the airport property and area potentially affected by airport improvements. A 400-foot reach of McDeed Creek (west of the runway) supports no wetland above the Ordinary High Water Mark (OHWM).
Figure 4‐6 shows the delineated wetland site (WL-01) and its associated wetland areas along McDeed Creek. Detailed information about wetlands in the project area is available in the Ennis Big Sky Airport Biological/Wetland Resources Findings memorandum found in Appendix D of this EA. Wild and Scenic Rivers
Within Montana, portions of the Flathead River system (North, Middle, and South Forks) and the Missouri River (between Fort Benton and the Charles M. Russell National Wildlife Refuge) have been designated as segments of the National Wild and Scenic River System. No rivers in Montana are currently under study to identify potential additions to the National System.
The Ennis Big Sky Airport is not located near any designated or proposed Wild and Scenic River segments in Montana.
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Figure 4-6: McDeed Creek and Associated Wetlands
Source: Ennis Big Sky Airport Biological/Wetland Resources Findings Memo, RESPEC, October 2016.
Representative Photographs of McDeed Creek at various times of the year.
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ENVIRONMENTAL ASSESSMENT ENNIS BIG SKY AIRPORT MADISON COUNTY, MT
5. ENVIRONMENTAL CONSEQUENCES
ROBERT PECCIA & ASSOCIATES
5. ENVIRONMENTAL CONSEQUENCES ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT
ENVIRONMENTAL CONSEQUENCES 5.1 Introduction This chapter discusses the potential effects the proposed improvements at EKS may have on the environmental resources of the project area as described in Chapter 4. The general study area for the evaluation of environmental effects includes primarily the airport and adjoining lands. The chapter considers the potential direct and indirect effects of implementing each alternative brought forward for analysis. 5.2 Air Quality FAA Order 1050.1F, Environmental Impacts: Policies and Procedures and the FAA’s Aviation Emissions and Air Quality Handbook ‐ Version 3 Update 1 (Air Quality Handbook) issued in January 2015 provide guidance for determining when aviation-related projects or actions require an air quality assessment and what level of analysis may be necessary. The guidance and procedures in the Air Quality Handbook also helps ensure that air quality assessments meet the requirements of NEPA, the CAA, and other relevant laws and regulations.
FAA’s guidance indicates the need to prepare an air quality assessment for actions that will likely result in a reasonably foreseeable increase in emissions. The approved forecast for EKS projects the number of annual aircraft operations at the airport to increase in the future even if improvements are not implemented. However, the implementation of the proposed action would affect how aircraft operate/taxi on the airfield. Therefore, the air quality evaluation considered changes in emissions from current (2015) conditions, at the opening year of 2022, and through the reasonably foreseeable future year of 2027 with and without the Proposed Action. Assessment Methodology and Impact Evaluation Consistent with guidance in the Air Quality Handbook, an operational and construction emissions inventory was prepared to quantify air emissions with and without the project based on current and projected future conditions at the Ennis Big Sky Airport.
BridgeNet International (BridgeNet), an airport air quality consultant, was retained in late 2017 to prepare the air quality assessment for EKS. BridgeNet completed an operational emissions inventory based on current (2015) and projected future annual aircraft operations and aircraft fleet characteristics at the airport. Two future years—2022 (representing the anticipated year of implementation) and 2027 (representing a time 5-years after project implementation) were evaluated. The operational emissions inventory was designed to quantify the amounts of criteria pollutant emissions (and their precursors) associated with the current aircraft operations and project alternatives. Based upon current and forecasted activity levels along with appropriate emission factors, the results provide a measure of the magnitude of the potential air quality impacts and enable comparisons of emissions between project alternatives and significance criteria.
The emissions inventory for aircraft was estimated using AEDT Version 2d released on September 27, 2017. As noted in the FAA’s September 9, 2016 guidance, the most current version of the AEDT must be used to perform all noise, fuel burn and emissions modeling for FAA actions. The results of
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5. ENVIRONMENTAL CONSEQUENCES ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT emissions modeling are typically expressed in units of tons/year segregated by pollutant type and emission source for the year(s) of interest.
BridgeNet also prepared a construction emissions inventory to quantify the amounts (i.e., mass) of criteria pollutant emissions (and their precursors) associated with the construction of the proposed project. Emissions from the use of construction equipment are temporary, and in the case of airport projects, the equipment is operated within a restricted area not usually accessible to the general public, and likely enclosed by security fencing. Project-related construction emissions were estimated using the Airport Construction Emissions Inventory Tool (ACEIT)1 and the EPA’s MOVES2014a models.
To evaluate potential air quality impacts, the results of the emissions inventories for the year 2015 and future years 2022, and 2027 for the No Action Alternative and the Proposed Action were compared to the established annual de minimis threshold levels of 100 tons/year for the NAAQS- regulated pollutants or their applicable precursors. The de minimis thresholds represent emissions levels for criteria or precursor pollutants that if exceeded, may cause or contribute to a new or continued violation of the NAAQS in nonattainment or maintenance areas. Although requirements to meet the de minimis levels do not apply since Madison County is in attainment, they were examined in the air quality assessment to provide an indication of the magnitude of the impacts associated with project alternatives. If the net emissions associated with the alternative do not exceed an applicable de minimis threshold(s), then emissions levels are considered negligible and the alternative would not have the potential to cause an exceedance of the NAAQS (or the MAAQS).
Since Madison County is an area designated as attainment for the NAAQS, the proposed improvement project at the Ennis Big Sky Airport is not subject to the General Conformity Rule. Direct and Indirect Impacts No Action Alternative Operational‐Related Emissions (2015, 2022 and 2027). No new or improved facilities or changes in the current existing physical configuration and layout of the airport would occur so the layout of the airport in future years 2022 and 2027 would be the same as the existing facility.
By 2022, total annual aircraft operations are expected to reach 13,130 operations (an increase of 7.6% over the 2015 baseline level of 12,200 operations). By 2027, aircraft operations are expected to increase further to 13,596 operations (or an increase of 11.4% over 2015 operations). More detail about the assumptions used for the emissions inventory is provided in the Air Quality Assessment found in Appendix F of the EA.
Table 5.1 presents the results of the operational emissions inventories for the years 2015, 2022, and 2027 at EKS. The inventory results anticipate a gradual increase in air pollutant emissions over time due to an incremental increase in the number of annual operations at EKS. Although slight
1 The ACEIT was developed by the Transportation Research Board (TRB), Airport Cooperative Research Program (ACRP). ACRP Report 102, Guidance for Estimating Airport Construction Emissions, 2014 http://www.trb.org/ACRP/Blurbs/170234.aspx.
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5. ENVIRONMENTAL CONSEQUENCES ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT increases in air pollutant emissions are predicted by 2027, advances in aviation technologies, operations, systems, and fuels are expected make the general aircraft fleet more efficient and operate with lower emissions over the foreseeable future.
Table 5.1: Operational Emissions Inventory Results – No Action Alternative Years 2015, 2022 and 2027
Criteria Pollutants and Precursors (Tons/Year) YEAR CO VOC NOx SO2 PM2.5 PM10 2015 86.9 3.1 0.6 0.2 0.1 0.1 2022 91.5 4.1 1.0 0.2 0.1 0.1 2027 94.2 4.3 1.1 0.3 0.1 0.1 Source: BridgeNet International using AEDT and Synergy Consultants, March 2018 * from 40 CFR 93.153(b)(1)
Construction Emissions: Under the No Action Alternative, the proposed improvements at EKS would not occur, and thus, there would be no construction emissions except for minor emissions associated with actions to maintain the airport’s current facilities when needed. Since the No Action Alternative includes only necessary maintenance activities at the airport, no construction emissions inventory was prepared.
Proposed Action Operational‐Related Emissions (2022 and 2027). The Proposed Action is not expected to change the number of aircraft operations or the fleet mix operating at EKS. Extending Runway 16/34 approximately 1,000 feet to the north would represent a notable change in the layout of the airport when compared to the present facility. This facility change would affect emissions because aircraft would be required to taxi an additional distance from the runway end on departure or arrival, depending upon the direction of their approach or departure. Assuming an average 10 knot taxi speed, it was estimated that the taxi time would increase by 41.3 seconds for arrivals on Runway 16 and increase by 53.1 seconds for departures on Runway 16. This additional taxi time was added to the default assumed for the No Action Alternative.
Assumptions used for the emissions inventory and the results of the analysis for the Proposed Action are documented in the Air Quality Assessment found in Appendix F of the EA.
The estimated amount of operational emissions associated with the implementation of the Proposed Action for the years 2022 and 2027 are shown in Table 5.2. For comparison purposes, the table also shows the predicted emissions of the No Action Alternative for the same years and identifies the potential change in annual operational-related emissions due to implementation of the proposed airport improvements.
In 2022, the Proposed Action would result in 13.6 more tons of CO, 1.1 tons more of NOx, and less than 0.2 tons for all other pollutants combined when compared to the No Action Alternative. In 2027, the Proposed Action would create an additional 2.9 tons of CO, 0.2 ton of NOx, and no change in the other pollutants when compared to the No Action Alternative for the same future years. Predicted emissions of pollutants are expected to decrease between 2022 and 2027 under the
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5. ENVIRONMENTAL CONSEQUENCES ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT
Proposed Action. This is due to anticipated advances in new technologies, operations, systems, and fuels that are expected to make the general aircraft fleet more efficient and operate with lower emissions over the foreseeable future.
Table 5.2: Future Operational Emissions – Proposed Action
Criteria Pollutants and Precursors (Tons/Year)
CO NOx VOC SO2 PM25 PM10 YEAR 2022 No Action Alternative 91.5 4.1 1.0 0.2 0.1 0.1 Proposed Action 105.1 5.2 1.1 0.3 0.1 0.1 PROJECT-RELATED CHANGE 13.6 1.1 0.1 0.1 0.0 0.0
YEAR 2027 No Action Alternative 94.2 4.3 1.1 0.3 0.1 0.1 Proposed Action 97.1 4.5 1.1 0.3 0.1 0.1 PROJECT-RELATED CHANGE 2.9 0.2 0.0 0.0 0.0 0.0 Source; BridgeNet International, March 2018 Note: De minimis threshold levels for pollutants of interest are 100 tons/year.
The data in Table 5.2 shows that the predicted project-related (net) changes in operational emissions would be below de minimis values with the Proposed Action. Since the project-related changes in emissions associated with this alternative do not exceed any applicable de minimis threshold values, then emissions levels are considered negligible. Madison County is currently in attainment for the NAAQS (and MAAQS) and the estimated future emissions from aircraft operations at EKS would not have the potential to cause exceedances of these federal and state air quality standards. For these reasons, no significant impacts to air quality are expected.
Construction Emissions. Construction-related emissions are primarily associated with the exhaust from heavy equipment, delivery vehicles, and construction worker vehicles traveling to and from the work site or around construction areas. Fugitive dust emissions can be generated from site preparation, land clearing, material handling, and demolition activities. Construction emissions may also be realized from the disposal of construction debris and the production of aggregate base courses, asphalt, or concrete. These emissions are temporary in nature and generally localized to the construction site and the roadways used to access the construction area.
Table 5.3 presents the estimated construction emissions from combustion and fugitive emission sources associated with the Proposed Action. The estimated emissions were determined based upon forecast construction equipment and resource needs, activity levels and appropriate emission factors for year 2019, assuming all construction projects at the airport occur in one year. Section 1.5 in Chapter 1 notes that the projects are expected to be completed between 2019 and 2022 at EKS. Recognizing that construction would likely occur across three to four years, analyzing these emissions with the assumption that construction would occur in one year will produce results that are conservatively high.
For a construction emissions inventory, there is no threshold of significance in FAA guidance. However, comparing emissions values to the General Conformity de minimis thresholds is often
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5. ENVIRONMENTAL CONSEQUENCES ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT used as a guide. If Madison County was in maintenance for pollutants, the de minimis threshold would be 100 tons for each pollutant shown Table 5.3. Since Madison County is in attainment, and construction emissions would be well below any of the de minimis thresholds, these emissions are not expected to be significant.
Table 5.3: Construction Emissions Inventory Results – Proposed Action (Construction Year)
Criteria Pollutants and Precursors (Tons/Year)* EMISSIONS SOURCE CO NOx VOC SO2 PM2.5 PM10 Non-Road 3.0 7.5 1.4 <0.1 0.4 0.4 On-Road 7.7 1.5 0.5 <0.1 <0.1 <0.1 Fugitive 2.2 0.1 34.2 <0.1 - 1.7 TOTAL EMISSIONS 13.0 9.2 36.1 <0.1 0.4 2.1 Source: Synergy Consultants, using ACEIT, March 2018. * For analysis purposes, it was conservatively assumed all construction occurs in 2019 rather than incrementally over several years. Mitigation Based on the analysis of the operational and construction emissions inventories, implementing the Proposed Action would not be expected to cause any long-term air quality impacts or violations of the NAAQS or MAAQS. Therefore, no mitigation for air quality impacts would be necessary.
As the discussion of construction emissions presented above indicates, temporary and localized air quality impacts may occur during construction. These temporary impacts and their degree of adversity would be reduced as construction activities are completed. Best management practices (BMPs) such as water application on unpaved or unvegetated surfaces to minimize airborne dust during construction and revegetating disturbed areas as soon as possible after disturbance would be incorporated to help minimize the potential for air quality impacts.
The provisions of FAA Advisory Circular 150/5370-10F, Standards for Specifying Construction of Airports, (September 30, 2011), Item P-156, Temporary Air and Water Pollution, Soil Erosion, and Siltation Control, will also be incorporated into the project specifications. Other FAA guidance concerning construction controls would be evaluated for provisions that may be incorporated into the contract specifications to minimize the potential impacts of construction activities.
An Air Quality Permit from the MDEQ Air Resources Management Bureau is required for the operators of gravel crushers and asphalt plants who supply such materials construction of the Proposed Action. Conclusion Based on the analyses discussed above, the Proposed Action is not expected to cause any long-term air quality impacts or violations of the NAAQS or MAAQS due to either operational or construction emissions. Therefore, the Proposed Action will not significantly impact air quality and mitigation for air quality impacts would not be necessary.
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5.3 Coastal Resources There are no coastal barrier islands or designated coastal zones in the State of Montana. Therefore, neither the No Action Alternative nor the Proposed Action would affect coastal resources. 5.4 Land Use Chapter 11 of the FAA’s Order 1050.1F Desk Reference states that “the compatibility of existing and planned land uses with proposed aviation actions is usually determined in relation to the level of aircraft noise.” There is an obligation to assess the compatibility of land uses near an airport to ensure those uses do not adversely affect safe aircraft operations. The FAA’s guidance indicates that if a project would result in other significant impacts having land use implications, the effects on land use may be described under the appropriate impact sections.
Consistent with this guidance, potential land use impacts are discussed in this section and other sections of this chapter including Farmlands (Section 5.6), Historical, Architectural, Archaeological, and Cultural Resources (Section 5.9), Noise and Compatible Land Use (Section 5.13), Socioeconomics, Environmental Justice, and Children’s Environmental Health and Safety Risks (Section 5.14), and Cumulative Impacts (Section 5.16). Other than the significance thresholds established for the resource categories identified above, FAA Order 1050.1F does list any specific significance thresholds under the Land Use category. Direct and Indirect Impacts No Action Alternative The No Action Alternative is not anticipated to result in any impacts to land use. This alternative would not change the current land uses at the airport or in the surrounding area.
The alternative would not change aircraft-related noise levels or require facility alterations that would affect existing land uses. The County’s AAA regulations, adopted in August 2014, would remain in place to protect the compatible land use necessary for operations at EKS.
Proposed Action Minor changes in the use of lands adjoining the airport are anticipated due to the implementation of the Proposed Action. The Proposed Action includes the acquisition of two small tracts of land from residential properties in the Shining Mountains Airpark Subdivision adjoining the east side of the Airport (Tracts 4-A and 4-B) and securing a perpetual easement on a tract of land owned by the State of Montana north of the Airport (Tract 6). Except for Tract 4-B, located just southeast of the airport, the properties needed for the improvements are generally undeveloped tracts. A residence and several outbuildings exist on Tract 4-B; however, the entire parcel is not proposed for acquisition and the area proposed for acquisition does not contain any structures. State lands north of the airport property are used for livestock grazing. Expanding and improving the airport as proposed with the Proposed Action would not conflict with adjoining land uses since similar uses have existed near the Airport for many years.
As noted in Section 1.1.2 of the EA, Madison County has previously acquired several adjacent lands to the Airport. Tract 29-A-1, and portions of Tracts 13-A, 13-B, 20-A, and 20-B, and the Longhorn
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Ranch parcel (located along the eastern edge of the Airport) were acquired to ensure land use compatibility with the airport environs and to protect design and airspace surfaces for aviation purposes. These parcels are sufficient in size to accommodate the OFA required for the Proposed Action and the relocation of the windcone, segmented circle, and AWOS III/P onto Tract 20-A. Land uses on the privately-owned parcels that adjoin Tracts 29-A-1, 13-A, 13-B, 20-A, and 20-B, and the Longhorn Ranch parcel would not change. The conservation easement established by the owners of the Longhorn Ranch continues to be in effect on the 6.41-acre parcel acquired by the County as well as the remainder of the Longhorn Ranch property. Any necessary airspace grading/excavations in this area would include adequate topsoil stripping and seeding reclamation as part of the improvements, as would be completed on the other areas disturbed by the Proposed Action.
Existing fencing along the former airport property boundary within Tracts 4-A and 4-B, Tract 6, and previously acquired parcels (Tracts 29-A-1, 13-A, 13-B, 20-A, and 20-B, and the Longhorn Ranch parcel) would be removed and new fencing would be installed along the revised eastside airport property boundary. Mitigation Madison County would modify its AAA regulations for EKS to recognize the proposed northerly extension of Runway 16/34, the 12.5-foot easterly centerline shift, and dimensional changes in airspace required by the proposed transition from a B-II-5000 to C-II-5000 airport. This would require modifications to the map showing the AAA and revising the associated regulations as appropriate. The updated ALP set for the C-II-5000 facility would also need to be incorporated into the AAA regulations. Conclusion
Implementation of the Proposed Action would result in minor changes in the use of lands adjoining the airport. The Proposed Action would require the acquisition of small tracts of land from two residential properties in the Shining Mountains Airpark Subdivision adjoining the east side of the airport (Tracts 4-A and 4-B) and convert the land to airport use. No residences or structures on these properties would be acquired. Additionally, a perpetual easement on a tract owned by the State of Montana at the north end of the Airport (Tract 6) used for agricultural purposes would be secured and the land would be incorporated into the airport property.
Previously acquired lands by Madison County adjacent to the airport (Tract 29-A-1, portions of Tracts 13-A, 13-B, 20-A, and 20-B, and a 6.41-acre parcel of land formerly part of the Longhorn Ranch) are currently used to ensure land use compatibility with the airport environs and to protect design and airspace surfaces. These lands would facilitate the implementation of the Proposed Action by providing sufficient area for the required OFA and to relocate the windcone, segmented circle, and AWOS III/P.
The Proposed Action would remove the existing fencing marking the former airport property boundary within Tracts 4-A and 4-B, Tract 6, and the previously acquired eastside parcels (Tracts 29-A-1, 13-A, 13-B, 20-A, and 20-B, and the Longhorn Ranch parcel) and install new fencing along the revised eastside airport property boundary. Land uses on the privately-owned parcels that adjoin Tracts 29-A-1, 13-A, 13-B, 20-A, and 20-B, and the Longhorn Ranch parcel would not change.
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Overall, implementation of the Proposed Action would not significantly impact land uses on properties adjoining the airport. 5.5 Department of Transportation Act: Section 4(f) FAA Order 1050.1F indicates a significant impact would occur when the Proposed Action either involves a “physical use” or “constructive use” of Section 4(f) property. A physical use of Section 4(f) property occurs if the proposed action or alternative would involve an actual physical taking of the property through purchase of land or a permanent easement, physical occupation of a portion or all of the property, or alteration of structures or facilities on the property. A constructive use occurs when an action substantially impairs the activities, features, or attributes of the resource that contribute to the resource’s significance or when an action substantially diminishes the enjoyment of the resource. Under certain conditions, the temporary occupancy of a Section 4(f) property for project construction-related activities can also represent a use.
The responsible FAA official must also consider if any mitigation proposed would eliminate or reduce the effects of the use below the threshold of significance and whether the mitigation is satisfactory to the agency having jurisdiction over the protected resource. Direct and Indirect Impacts No Action Alternative The No Action Alternative would not affect any federal, state or local parks, recreation areas, wildlife or waterfowl refuges, or historic or archeological properties that are listed, or eligible for inclusion, on the NRHP. The alternative would not affect any lands in the Beaverhead-Deerlodge National Forest or the Madison Valley IBA.
Proposed Action The proposed improvements at the Ennis Big Sky Airport would not impact any federal, state or local parks, recreation areas, or wildlife or waterfowl refuges because no such properties exist adjacent to the airport or on lands proposed for acquisition. The Proposed Action would not result in any physical uses, constructive uses, or temporary occupancies of any parks, recreation areas, or refuges.
Cultural resources surveys for EKS identified one NRHP-eligible historic site on the airport property—the Granger Ditch (24MA2400). Although a section of the Granger Ditch crosses the western portion of the airport property, no activities or facility modifications associated with the Proposed Action would occur in or near the historic irrigation ditch. For this reason, the FAA made a determination of No Historic Properties Adversely Affected and submitted the determination to the Montana SHPO on March 15, 2018. The Montana SHPO concurred with the No Historic Properties Adversely Affected determination on April 2, 2018. Therefore, the proposed airport improvements would not result a physical or constructive use of the NRHP-eligible Granger Ditch. Construction-related activities would not cause any impacts to the historic irrigation ditch.
The Beaverhead-Deerlodge National Forest (which encompasses the Lee Metcalf Wilderness Area) represents a potential Section 4(f) resource. However, the Proposed Action would not result in direct impacts to the National Forest land because the proposed airport improvements do not
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5. ENVIRONMENTAL CONSEQUENCES ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT require the acquisition of any property associated with the National Forest. Implementation of the Proposed Action would not affect roads in the area used to access the National Forest.
Given the proximity of the airport to the National Forest, some aviation-related noise is already apparent on nearby forest lands. However, the Proposed Action would not result in notable changes to flight patterns to and from the airport and would not be expected to notably increase aviation- related noise levels on public forest lands in the area. Current approach and departure procedures at EKS do not require aircraft to fly over land in the National Forest or Lee Metcalf Wilderness. Arrival and departure procedures would be amended under the Proposed Action; however, recommended flight paths and approach and departure paths (including elevations) beyond the airport boundary would essentially remain unchanged from current conditions. Circling operations, which occur north or south of the Airport over the Madison Valley due to the high mountainous terrain that exists to the east, would not change. For these reasons, there would be no constructive use of National Forest lands because the Proposed Action would not impair the dispersed recreational activities, features, or attributes of the multiple use lands within the Beaverhead- Deerlodge National Forest (including the Lee Metcalf Wilderness Area) or diminish the enjoyment of these public lands.
No direct or indirect impacts are anticipated to the Madison Valley IBA. The Ennis Big Sky Airport is located on the opposite (east side) of US Highway 287 about 3 miles from the boundary of this Audubon Society-designated IBA along the Madison River. There would be no physical use of public or private land encompassed by the IBA and the proposed airport improvements would not affect any roads used to access the area. The Proposed Action would not result in notable changes to flight patterns to and from the airport or aviation-related noise within the IBA. There would be no constructive use of the Madison Valley IBA because the Proposed Action would not impair the activities, features, attributes of the IBA and would be unlikely to diminish the enjoyment of the area by visitors.
The proposed airport improvements would not result in any temporary occupancies of land within the Beaverhead-Deerlodge National Forest (including the Lee Metcalf Wilderness Area) or the Madison Valley IBA. Mitigation Since no impacts to Section 4(f) property are anticipated, no mitigating measures are necessary. Conclusion The Proposed Action would not use any federal, state or local parks, recreation areas, or wildlife refuges of national, state, or local significance. Although a section of the NRHP-eligible Granger Ditch (24MA2400) exists on airport property, the improvements associated with the Proposed Action would not impact the historic irrigation feature. Therefore, no physical, constructive, or temporary use of any Section 4(f) property would occur due to the implementation of the Proposed Action.
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5. ENVIRONMENTAL CONSEQUENCES ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT
5.6 Farmlands The FPPA regulates actions with the potential to convert existing Farmlands (prime farmland, unique farmland, or farmland of statewide or local importance) to nonagricultural uses. Direct impacts to farmlands typically involve the conversion of farmlands to non-agricultural use. Indirect conversion of farmland could occur if a project limits access to farmable land or otherwise inhibits the viability of farming or farm operations on agricultural lands. Any airport development action funded under the AIP or subject to FAA approval that would permanently convert designated Farmlands to a non-agricultural use is subject to FPPA coordination.
Significant impacts to Farmlands are determined by completing the NRCS Farmland Conversion Impact Rating Form (AD-1006) and assigning points for numerous site assessment criteria and for the farmland’s relative value (as determined by the NRCS). Site assessment scores range from 0 to 160 points. Scores for the relative value of farmland range from 0 to 100 and represent the site’s value for agricultural production. A combined total of the relative value and site assessment scores between 200 and 260 on Form AD-1006 indicates a significant impact. Combined scores between 161 and 200 suggest the potential to adversely affect important farmlands and require considering alternatives or measures to help reduce the acreage of converted Important Farmland. According to FAA guidance regarding farmland impacts, sites receiving a total score of less than 160 need not be given further consideration for protection, and no alternative sites need be evaluated.
Airport development projects that would convert important farmland must be coordinated with the local NRCS field office. Coordination with the NRCS in Missoula about the proposed airport improvement action initially occurred on February 22, 2018 when Form AD-1006 was submitted for the Sponsor’s Proposed Action. Relevant correspondence from the agency can be found in Appendix A of the EA. Direct and Indirect Impacts No Action Alternative The No Action Alternative would be implemented only on existing airport property and would not change the agricultural uses occurring on some adjoining lands. Lands already committed to urban development (including airport developed areas) are not subject the FPPA. Therefore, no impacts to soils designated as Farmland by the NRCS would occur under the No Action Alternative.
Proposed Action In accordance with the FPPA, a USDA Farmland Conversion Impact Rating Form AD-1006 was processed for the proposed airport improvement project at EKS. The implementation of the Proposed Action would result in the conversion of 20.99 acres (3.17 acres on Tracts 4-A and 4-B and 17.82 acres of State Land in Tract 6) of Farmland of Statewide Importance and Farmland of Local Importance.
The direct conversion of Farmlands would result from the acquisition of land necessary to extend Runway 16/34 and parallel taxiway and to provide the associated OFA and provide additional runway protection for Runway 16/34. The land acquisition would also help ensure compatible land use adjacent to EKS. No indirect conversion of Farmland would result from the
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5. ENVIRONMENTAL CONSEQUENCES ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT implementation of the Proposed Action.
The total site assessment points for the Proposed Action was calculated to be 86 on Form AD-1006 considering input received from the NRCS on March 2, 2018 and consideration of appropriate site assessment criteria. In accordance with FAA Order 1050.1F, a total score on Form AD-1006 below 160 does not require further analysis. Since the total is less than 160 points, no further analysis is required. The Proposed Action would not have a significant impact on Farmlands and no consideration for protection is necessary. The completed form has been processed by the NRCS and a copy is provided in Appendix A of the EA. Conclusion The Proposed Action would result in the conversion of 20.99 acres of Farmlands due the acquisition of land required to extend, widen, and reconstruct Runway 16/34 and upgrade the facility to meet the critical aircraft design standards. The significance of the potential farmland impact was determined through coordination with the NRCS and by conducting a site assessment using the NRCS Farmland Conversion Impact Rating Form AD-1006. The assessment showed the Proposed Action would not have a significant impact on farmlands and that no further consideration for protection of Farmlands is necessary. 5.7 Biological Resources (Including Fish, Wildlife and Plants) This section addresses the potential effects to fish, wildlife or plant resources at or near EKS including threatened, endangered, proposed and candidate species listed under the ESA by the USFWS and Montana species of concern. According to FAA Order 1050.1F, factors to consider in evaluating the context and intensity of potential environmental impacts for fish, wildlife or plant include: short-term and long-term changes in the size and age composition of populations, effects on reproductive success rates, natural or non-natural mortality, and the ability of a species to maintain adequate population levels.
FAA Order 1050.1F indicates a significant impact would occur when the USFWS determines that the action would be likely to jeopardize the continued existence of a federally-listed threatened or endangered species or would result in the destruction or adverse modification of federally- designated critical habitat.
For the analysis of potential impacts to biological resources, the existing airport property and agricultural and rural residential lands immediately adjacent to EKS are of primary interest. Direct and Indirect Impacts to Fisheries Four intermittent drainages pass through the project area at the Ennis Big Sky Airport—McDeed Creek, Boulder Creek, and two unnamed tributaries to Boulder Creek. None of these drainages crossing the airport property provides aquatic or fish habitat and none are managed as sport fisheries by the MFWP. The Granger Ditch does not provide habitat for fish or other animal aquatic species. There are no federally-listed fish species occurring within Madison County and no occurrences of fish species designated as Montana Species of Concern within the project area at EKS.
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No Action Alternative
The No Action Alternative involves no project-related construction activities and perpetuates routine maintenance activities at the airport. Since there are no streams or surface waters on the airport property that support fish, there would be no impact to fisheries.
Proposed Action
Although activities associated with the Proposed Action would affect McDeed Creek, Boulder Creek, and two unnamed tributaries to Boulder Creek, no impacts to fisheries are anticipated since these streams do not support fish. Direct and Indirect Impacts to General Wildlife Resources Habitat for wildlife species at or near EKS is limited due to human activities and disturbances related to the development and use of the airport, agricultural activities, residences, and roads. However, cover, forage, and movement corridors likely exist on or near the airport for some birds and other commonly occurring wildlife species in the area.
Information provided by the MNHP shows occurrences of five Species of Concern (Ferruginous Hawk, Townsend's Big-eared Bat, Great Blue Heron, Grizzly Bear, and Wolverine) within a 12- square-mile area centered on the airport. Montana Species of concern are addressed in Section 5.7.6. Potential effects to federally-listed species are addressed in Section 5.7.5.
No Action Alternative The No Action Alternative does not include any project development activities and would perpetuates routine maintenance activities at the airport. Previous development in the Shining Mountains Airpark Subdivision and of the airport has already affected wildlife use and eliminated minor amounts of habitat for some species. No new impacts to wildlife species or their associated habitats near EKS are anticipated with this alternative. The existing airport property has been highly modified by the construction and operation of the airfield. As a result, airport lands do not represent high-quality wildlife habitat and some wildlife species that formerly used the airport lands have likely already been displaced to other lands in the area with more favorable habitat conditions.
Proposed Action The provision of the new airport facilities proposed with the Proposed Action would result in the disturbance and/or minor loss of wildlife and bird habitat from the upland habitats that exist on and adjoining the airport. Extending, widening, and reconstructing the runway; reconstructing and extending the parallel taxiway to the end of extended Runway 16; and modifying apron and taxilane areas would remove surface vegetation that provides habitat for songbirds and small mammals that inhabit the area. The removal of vegetation would be confined to those areas associated with construction. The loss of vegetation due to construction activities would likely result in the permanent or temporary displacement of some species. However, sufficient areas of adjacent suitable habitat exist for individuals displaced by construction activities and the resulting permanent modifications of the project area.
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Wildlife fencing is an important safety consideration for aircraft that operate at faster approach speeds and under IFR weather conditions. Both of these conditions occur with increasing frequency at EKS. Since pronghorn antelope, elk, and moose are ungulate species commonly or occasionally seen on or near the airport property, installation of a 9-foot-high wildlife fence around the perimeter of the airport is proposed with the Proposed Action. The purpose of the fencing is to prevent wildlife incursions onto the airport and increase safety for airport users. Wildlife fencing would change local movement patterns by ungulates and prevent them from using habitat on or near the airport. These effects are minor given the large amount of similar habitat in the area and the fact that airport lands lack essential habitat features like water sources. Direct and Indirect Impacts to Plants Vegetation at and around the Ennis Big Sky Airport consists of numerous cool weather grasses (fescues, wheatgrasses, and quackgrass) and sedges as well as the occasional prickly pear cactus. The MNHP shows no rare and sensitive plant species are known to occur on or near the airport. Biologists reviewing the airport property and nearby lands in September 2016 observed several County noxious weed species including thistles.
No Action Alternative The No Action Alternative would not cause impacts to vegetation beyond those already occurring due to normal airport operation and maintenance activities like mowing and weed control. The No Action Alternative would not promote the spread of noxious weeds or invasive species because ground-disturbing construction activities on the airport property are not necessary.
Proposed Action This airport improvement alternative would result in the permanent loss of vegetation in the areas where the runway would be extended and widened (including respective safety and object free areas; in areas to be graded for the removal of airspace obstructions; and where work is necessary to provide a full-length parallel taxiway, taxilanes, hangars, and modified apron areas. The area of ground disturbance for the Proposed Action is estimated to be 150 acres. Much of the area that would be disturbed by this alternative has already been modified by previous airport construction or maintenance activities. In areas where the ground is disturbed as a result of construction activities, the spread of noxious weeds or invasive species is possible.
Based on the information obtained from MNHP, no rare and sensitive plant species are known to occur in the vicinity of EKS. For this reason, no impacts to Montana plant Species of Concern are anticipated with the Proposed Action.
Potential impacts to vegetation and plant communities in the area due to the required earthwork for the proposed improvements would be notable but only temporary in nature. Some vegetation species impacted by construction activities should regenerate naturally and disturbed areas would be promptly reseeded with desirable plant species providing new vegetation cover. Direct and Indirect Impacts to Migratory Birds and Eagles The Migratory Bird Treaty Act (MBTA) and Executive Order 13186 “Responsibilities of Federal Agencies to Protect Migratory Birds” provide protection for migratory bird species including
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5. ENVIRONMENTAL CONSEQUENCES ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT protection of their nests and eggs. Additionally, eagles are protected under the Bald and Golden Eagle Protection Act and the MBTA.
Information from the USFWS IPAC Resource List (found in Appendix D) suggests 22 species of migratory birds could potentially use lands at or near the Ennis Big Sky Airport as year-round or breeding habitat. Bald eagles and golden eagles are among several raptor species that may occur near EKS. Bald eagles are known to use habitat along the Madison River and nest along the river within 5 miles of the airport.
No Action Alternative The No Action Alternative involves no project-related construction activities. Routine maintenance and mowing likely results in the short-term disturbance or displacement of some migratory birds that use airport lands. Airport lands lack nesting or roosting habitat for eagles and may only occasionally provide foraging opportunities for carrion or small mammals. There are no known eagle nests within a mile of the airport. For these reasons, no impacts to migratory birds or eagles are anticipated.
Proposed Action The Proposed Action would result in the disturbance and/or minor loss of grassland habitat on and adjacent to the airport which is available for use by migratory birds. As noted in the Ennis Big Sky Airport Biological/Wetland Resources Findings memorandum (found in Appendix D of this EA), six species of migratory songbirds (three species of sparrows, western meadowlark, lapland longspur, and horned lark) were observed in grassland habitats on or near the airport during field work in 2016.
Construction to extend, widen, and reconstruct the runway; provide a full-length parallel taxiway; and modify apron, taxilane, and hangar areas would permanently remove areas of grassland communities that provide potential cover and foraging habitat for some migratory birds. Construction activities may also temporarily displace birds from grassland habitat at the airport. These impacts to migratory birds are considered minor due to the large amount of similar habitat that exists on nearby lands and because construction activities would be short-term and localized to work areas.
Coordination with the USFWS on March 15, 2018 established that there are no known eagle nests within a mile of the project, although the general surrounding area may receive year-round eagle use. Given the developed nature of the project area at the airport, negative effects to bald and golden eagles are not expected. Since there are no suitable trees for bald eagle nesting on the airport property or within 0.5 miles of the airport, it is unlikely that eagle nesting would occur in the area. Foraging opportunities for eagles in the area would not change.
For the reasons discussed above, no impacts to migratory birds or eagles are anticipated for the Proposed Action. Direct and Indirect Impacts to Federally-Listed Species Section 7 of the ESA requires the FAA to coordinate USFWS to determine if a proposed action would affect a federally-listed species or habitat critical to that species. Coordination with the USFWS on
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March 15, 2018 indicates that five federally-listed species occur within Madison County including Ute ladies’ tresses, Canada lynx, red knot, wolverine, and whitebark pine. The USFWS indicated the Canada lynx and wolverine may rarely occur as transients in the general project area. Only one known migratory red knot occurrence was recorded in the Ennis area several decades ago. There are no documented occurrences of Ute ladies’ tresses near EKS, although potential habitat for this species occurs west of the project area. Whitebark pine habitat does not occur in the immediate vicinity or the airport.
As noted in Chapter 4, the status of the Greater Yellowstone Ecosystem grizzly bear DPS changed since USFWS coordination for this project was conducted in March 2018. Grizzly bears were delisted when initial coordination occurred but due to a U.S. District Court ruling in September 2018, grizzly bears were once again placed on the ESA list. The species is listed as Threatened within Madison County. Habitat for grizzly bears does not occur at the Airport, but it is possible the species could infrequently occur in the general project area.
No Action Alternative The No Action Alternative involves no project-related construction activities and perpetuates routine maintenance activities at the airport. The No Action alternative would not cause direct or indirect effects on any federally-listed threatened, endangered, proposed or candidate wildlife species or designated or proposed critical habitat in Madison County.
Proposed Action On March 15, 2018, Brent Esmoil (USFWS Montana Ecological Services Office) concluded that “based on project site habitat descriptions found in the October 2016 Memorandum (see Appendix D of the EA) and confined nature and proposed location of this proposed work in an existing developed airport setting, we do not anticipate its implementation would result in adverse effects to listed, proposed or candidate threatened or endangered species, or listed or proposed critical habitat.” A copy of the agency’s March 15, 2018 letter can be found in Appendix A of the EA.
Considering this input from the USFWS, and that no federally-listed species nor their habitat is found on or near the airport, implementation of this alternative would have no effect on Ute ladies’ tresses, Canada lynx, red knot, grizzly bears, wolverines, or whitebark pines. This conclusion is supported by the fact that habitats used by these species do not exist within the project area at EKS.
Although suitable habitat exists within the general project area, the airport property and adjacent lands lack the habitat components typically used by grizzly bears. The USFWS noted in its March 15, 2018 letter that grizzly bears may occasionally be seen in the general vicinity of EKS. However, data from the MNHP shows no reported occurrences of grizzly bears at or adjacent to the Airport. For these reasons, the Proposed Action is not expected to result in any direct, indirect, or cumulative impacts on grizzly bears.
Therefore, the Proposed Action is not anticipated to have any significant effect on listed, proposed or candidate threatened or endangered species, or listed or proposed critical habitat.
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Direct and Indirect Impacts to Montana Species of Concern Several Montana Species of Concern (ferruginous hawk, Townsend's Big-eared Bat, Great Blue Heron, grizzly bear, and wolverine) are known to occur within 1-mile of the airport; however, data from the MNHP shows none of these species are known to occur on the existing airport property or immediately adjacent lands. A roost site for the Townsend’s big-eared bat has been documented approximately 1.6 miles east of EKS. Bats may forage for insects in the project area, however, the existing airport property does not offer suitable roost sites for the species.
Occurrence data provided by the MNHP did not identify any plant Species of Concern on or adjacent to the airport.
No Action Alternative The No Action Alternative would not impact Montana Species of Concern because the alternative does not involve project-related construction activities and just perpetuates routine maintenance activities at the airport. MNHP data shows no previous occurrences of any Species of Concern on the airport or immediately adjacent lands.
Proposed Action No adverse impacts to Montana wildlife Species of Concern are anticipated. Although occurrences of several Species of Concern are known within 1-mile of the airport, mapping provided by the MNHP shows no occurrences of these species on the airport property or adjoining lands proposed for acquisition with this alternative. The airport property and lands proposed for acquisition do not provide suitable habitat for the Great Blue Heron or wolverines. Ferruginous hawks and grizzly bears could be infrequently seen in the area; however, the airport and adjoining lands do not provide essential habitat for these species. As discussed previously, the airport property and lands proposed for acquisition lack suitable roost sites for the Townsend’s big-eared bat. For these reasons, no impacts to Montana Species of Concern are anticipated with the Proposed Action. Mitigation for Impacts to Fish, Wildlife, and Plants No Action Alternative No mitigation measures are required or proposed for this alternative.
Proposed Action Disturbed surface areas would have topsoil stripped and stockpiled, for placement following excavation and embankment grading. Ground disturbed by construction activities will be revegetated with a desirable seed mix that is appropriate for the area and that will provide competition against the establishment and spread of invasive species. The provisions of FAA Advisory Circular 150/5370-10F, Standards for Specifying Construction of Airports, (September 30, 2011), Item T-901, Seeding, and Item T-908, Mulching, would be incorporated into the project specifications. Seeding activities will generally be conducted in the spring of the year (prior to May 15th) or the fall of the year (after October 15th), to minimize the amount of time disturbed areas remain uncovered and help ensure seed germination.
Before construction activities begin, a weed management plan will be developed in coordination
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5. ENVIRONMENTAL CONSEQUENCES ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT with the Madison County Weed District, to identify weed control strategies within the proposed project area. If chemical weed control is necessary, herbicides appropriate for use in riparian areas and around wildlife will be identified. Implementation of these measures will help prevent adverse effects due to the spread of noxious weeds on newly disturbed areas.
Research and coordination with the USFWS has determined there is no suitable habitat or known occurrences of federally-listed species on the airport or in the immediate vicinity of EKS. For this reason, impacts to these listed species are not anticipated and mitigating measures are not necessary.
The USFWS recommended that, to the extent practicable, necessary wetland and other vegetation clearing, grubbing, and filling construction activities be scheduled to avoid and minimize impacts to nesting birds, if present in the project area. The agency also recommended consulting the Service’s Conservation Measures website (https://www.fws.gov/birds/management/project-assessment- tools-and-guidance/conservation-measures.php) for applicable measures to help avoid or minimize impacts to birds in project design and construction. Several of the Conservation Measures suggested by the USFWS will be followed with the implementation of the proposed improvements at EKS including:
Clearly delineating and maintaining project boundaries (including staging areas) to minimize unanticipated impacts to grassland habitats in the area; Scheduling vegetation removal to occur outside of the peak bird breeding season (generally between April and August) to the extent practicable; Implementing soil erosion and dust control measures as needed; and Promptly reseeding disturbed areas to help prevent the spread of noxious or invasive plants. Although the presence of grizzly bears in the project area is not anticipated, the USFWS recommended the following voluntary best management practices/conservation measures as appropriate to reduce the potential risk of human-grizzly bear conflicts:
Promptly clean up any project related spills, litter, garbage, debris, etc. Allow no overnight camping within the project vicinity, except in designated campgrounds, by any crew member or other personnel associated with this project. Store all food, food related items, petroleum products, antifreeze, garbage, personal hygiene items, and other attractants inside a closed, hard-sided vehicle or commercially manufactured bear resistant container. Remove garbage from the project site daily and dispose of it in accordance with all applicable regulations. Notify the Project Manager of any animal carcasses found in the area. Notify the Project Manager of any grizzly bears observed near the project.
The contractor for the proposed airport improvements will be made aware of these best management practices/conservation recommendations during project implementation.
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Conclusion The Proposed Action requires work within several intermittent surface drainages; however, none of these drainages provide aquatic habitat or support fish. For these reasons, no significant impacts to fish or their habitat is anticipated due to the implementation of this alternative.
The Proposed Action would require the removal of minor amounts of grassland habitat used by common wildlife species and some migratory birds. The widening and extension of the runway associated with the proposed improvements may also permanently remove minor amounts of grassland habitat and displace some species during construction activities. However, these wildlife impacts are judged to be minor and insignificant due to the level of human activity, general lack of high-quality habitat for wildlife species in the vicinity of EKS, and the fact that a large amount of similar habitat for potentially affected species exists on nearby lands. Therefore, no significant impacts to general wildlife species is anticipated due to the implementation of the Proposed Action.
The Proposed Action would require clearing existing vegetation to build new airport facilities and ensure safe airport operations. Potential impacts to vegetation and plant communities in the area are judged to be minor and readily mitigated through prompt reseeding of disturbed areas and other measures to inhibit the spread of noxious weeds or invasive species.
Based on coordination with the USFWS and MNHP species occurrence records, implementation of the Proposed Action would have no effect on Ute ladies’ tresses, Canada lynx, red knot, grizzly bears, wolverines, or whitebark pines and would not impact any critical habitat for listed species. This conclusion was reached because the airport and immediately adjacent lands do not provide suitable habitat for the federally-listed species.
No adverse impacts to Montana wildlife Species of Concern are anticipated. Although occurrences of several Species of Concern are known within 1-mile of the airport, no occurrences of these species have been reported on the airport property or adjoining lands proposed for acquisition with this alternative.
For the reasons discussed above, no significant adverse impacts to fish, wildlife and plant species found on and near EKS are anticipated. 5.8 Hazardous Materials, Solid Waste, and Pollution Prevention Hazardous materials and hazardous wastes, if mishandled or if accidents occur, can pose risks to the public and environment through exposure. FAA Order 1050.1F does not establish a significance threshold for hazardous materials, pollution prevention, and solid waste. However, the FAA recommends the following factors be considered when making impact determinations: 1) the potential for violations of federal, state or local laws regarding hazardous waste handling or solid waste management; 2) the potential to affect a property on or eligible for the NPL; and 3) whether the proposed action produces an appreciably different quantity or type of hazardous waste or requires a substantially different waste collection or disposal process that exceeds local capacity.
Construction, renovation, or demolition associated with the implementation of airport improvement projects produces debris (i.e. dirt, concrete, asphalt, electrical components, etc.) that requires proper disposal. Construction or demolition of airport buildings may also produce debris.
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Direct and Indirect Impacts
Hazardous materials are products or wastes regulated by the EPA or the MDEQ. These include substances regulated under the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA or Superfund), the Resource Conservation and Recovery Act (RCRA), and regulations for solid waste management, above-ground storage tanks (ASTs) and underground storage tanks (USTs).
No Action Alternative
Airport operations include some activities with the minor potential for contamination of surface or groundwater. Those activities can include aircraft and airfield deicing, fuel storage and refueling, aircraft and vehicle cleaning and maintenance, and airfield maintenance. These activities, which periodically occur at the facility, are regulated under provisions of the CWA and would continue under the No Action Alternative.
The owners/operators of fueling services or storage tanks at the airport are responsible for safe refueling or deicing operations and have developed a Spill Containment and Cleanup Plan that can be implemented should a spill occur.
The only solid wastes generated by this alternative would be associated with the operation of and routine maintenance activities conducted at the airport. Solid waste generated at the airport are typically transported to container sites in the county.
Proposed Action The Proposed Action would not change the types or amounts of hazardous materials/substances (oil, grease, fuel, and other fluids associated with aircraft or surface vehicles) used at the airport for routine aircraft operations or maintenance activities.
No new fueling facilities are proposed at EKS. However, the FBO’s 100LL self-service equipment needs to be relocated to accommodate the proposed improvements and ensure the fueling equipment does not encroach on the runway OFA and departure surface.
McDeed Creek and fringe wetland areas, Boulder Creek and two unnamed tributaries are located on the Airport property and pass beneath the runway and/or partial parallel taxiway in culverts. The proposed improvements would not increase the potential for pollution of surface associated with aviation-related activities at the facility. New and longer culverts would be installed for the watercourses increasing the distance between operational areas of the runway and/or parallel taxiway and surface waters and wetlands. More information about the Proposed Action’s impacts to surface waters and wetlands can be found in Section 5.15.
Contamination of groundwater could most likely occur as a result of a spill of hazardous substances. A review of MDEQ’s records did not identify any USTs, leaking USTs, Petroleum Tank Release Compensation Fund (spill) sites, Remediation Response sites, or hazardous waste handlers at EKS. A spill response plan is maintained at EKS by the FBO and a spill response kit would be available to all airport users. Releases in excess of a reportable quantity would be reported to MDEQ and would be remediated to MDEQ specifications and standards. Such measures would effectively mitigate
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5. ENVIRONMENTAL CONSEQUENCES ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT any releases of oil, grease, fuel, and other fluids from negatively impacting surface and/or groundwater during airport operations.
Potentially hazardous materials used during construction of the Proposed Action would include paving materials, oils, fuel and grease from construction equipment, and minor amounts of paints and marking materials.
Herbicides and fertilizers may be used to maintain grassed areas or control weeds within the airport property. Application of fertilizers and herbicides would be consistent with the manufacturer's recommendations for storage and handling of the product.
While this alternative involves new construction, debris needing disposal off-site would be likely be generated due to the construction of the runway, full-length parallel taxiway, and apron areas. The Proposed Action would remove several buildings (two aircraft hangars, a shed, an outhouse, and the pilot’s shack) from the terminal area. The removal of the buildings would create notable amounts of demolition debris (wood waste, wire, metal, and concrete) requiring disposal. An inspection and laboratory testing of materials from the two hangars done in 2017 did not detect asbestos or lead-based paint in the structures. Hazardous materials were not suspected in the other buildings proposed for demolition. The demolition debris would likely be disposed of at the Ennis landfill or other site which is appropriately permitted to handle this material.
The earthwork necessary to extend Runway 16/34 to the north, reconstruct and widen existing sections of the runway, and to modify and extend the parallel taxiway to the end of the new runway may generate excess embankment material. The excess embankment may be crushed for use as pavement section aggregate, used on-site to provide new pads for future hangar development, stockpiled on the airport property, or possibly transported off the airport. The amount of excess embankment material and its appropriate use or disposition would be determined during final design activities.
The Proposed Action would reconstruct about 2,600 feet of the existing runway requiring the removal of the existing asphalt pavement in these reconstruction areas. Although the disposition of old pavement materials has not been determined, the asphalt pavement could be roto-milled and recycled or used in subbase course for new or future construction at the airport. Similarly, the base course gravels in the existing pavements could also be used to help create the base/subbase for the proposed runway, parallel taxiway modifications and extension, apron rehabilitation, or future construction at other locations on the Airport. Asphalt pavement material not used within the project limits or reused for another purpose must be disposed in conformance with applicable laws, rules, regulations and the Montana Solid Waste Management Act. Mitigation The operation of construction equipment poses a potential risk of minor leaks of fuel, lubricants, or hydraulic fluids in work areas. Contract documents will require the contractor to have a Spill Prevention, Control, and Countermeasure (SPCC) plan in place and measures to address an on-site spill. Additionally, the contractor will be required to obtain a General Permit for Storm Water Discharges Associated with Construction Activity from MDEQ. This permit requires the contractor to develop an erosion control plan to minimize the potential for water quality degradation.
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The Contractor will also be required to collect and properly dispose of all waste materials generated during construction. Conclusion The implementation of the Proposed Action would not change the types or amounts of hazardous materials/substances used at the airport for routine aircraft operations or maintenance activities. Further, the proposed improvements would not result in an increased potential for contamination of surface or groundwater at the airport.
Building demolition associated with the proposed improvements would generate notable quantities of demolition debris requiring disposal in the area. Construction activities are also likely to generate excess embankment material that can be stockpiled and used elsewhere at the airport and asphalt paving and base course materials that can be recycled or used for future construction at the airport. Any waste materials generated will be handled and disposed of in accordance with appropriate Federal, state and local laws and regulations.
While there is no known hazardous waste contamination within the Proposed Action area, the proposed project improvements have the potential to cause short-term, temporary impacts regarding hazardous materials, pollution prevention, and solid waste. Proper disposal of demolition debris and requirements for the contractor SPCC plan, measures to address an on-site spill, and a General Permit for Storm Water Discharges Associated with Construction Activity from MDEQ will reduce the overall potential for impacts.
Therefore, no significant impacts are expected to arise due to the Proposed Action. 5.9 Historical, Architectural, Archaeological, and Cultural Resources Section 106 of the NRHP requires that Federal agencies with jurisdiction over a federal or federally- assisted undertaking must consider the effect of the undertaking on properties listed in or eligible for listing in the NRHP.
A significant impact would occur if the Proposed Action results in an adverse effect to a property that is listed in or eligible for inclusion in the NRHP. An undertaking would adversely affect a property if it changes the characteristics of the historic property that qualify it for inclusion in the NRHP. Alteration to features of the property’s location, setting, or use may be relevant depending on a property’s significant characteristics and should be considered when determining potential effects. Direct and Indirect Impacts Metcalf Archaeological Consultants, Inc. conducted a cultural resource survey for lands potentially affected by the proposed improvements at EKS in September 2016 and performed supplemental cultural resource surveys in November 2017 and June 2019. The on-site reviews identified the Granger Ditch (24MA2400) and an isolated find (IF-CML-01) consisting of remnants of an old bottle and enamel ware and a prehistoric artifact.
The Granger Ditch was determined eligible for listing on the NRHP, but the isolated find was determined not eligible for the NRHP. The isolated find (IF-CML-01) is not eligible for the NRHP
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5. ENVIRONMENTAL CONSEQUENCES ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT because the artifacts may have originated from an adjacent property (Tract 4-B). The June 2019 supplemental cultural resource survey focused on Tract 4-B to help determine if the artifacts came from a larger site on the property. The supplemental survey found no cultural materials on the portion of Tract 4-B proposed for acquisition, so the origins of the artifacts associated with the isolated find remain undetermined.
A portion of Tract 4-A which adjoins the airport has not been surveyed for cultural resources because permission to access the property could not be obtained from the landowner. Archaeologists did conduct a visual inspection of lands within Tract 4-A readily seen from the airport property and Tract 4-B in June 2019. No cultural materials were observed on Tract 4-A during the visual inspection.
No previously recorded cultural sites exist near the Ennis Big Sky Airport.
No Action Alternative The No Action Alternative would not directly or indirectly affect any cultural resources on or near the airport.
Proposed Action The proposed improvements at the Ennis Big Sky Airport would not directly or indirectly impact any historic or archeological properties that are listed, or eligible for inclusion, on the NRHP. Although a section of the Granger Ditch (24MA2400) crosses the western portion of the airport property, no activities or facility modifications associated with the Proposed Action would occur in or near the historic irrigation ditch. Construction-related activities would not cause any temporary impacts to the historic irrigation ditch.
On February 5, 2018, nine Native American Tribes with historical ties or cultural interests in the Madison Valley were invited to consult on this undertaking by the FAA and advised of the FAA’s intent to make a determination of No Historic Properties Adversely Affected. To date, no responses have been received from any of the Tribes contacted.
Based on the findings of the cultural resources inventory and a review of the potential impacts associated with improving EKS as proposed, the FAA made a finding of No Historic Properties Adversely Affected and submitted the finding to the Montana SHPO on March 15, 2018. The Montana SHPO concurred with this determination in correspondence dated April 2, 2018. Relevant correspondence between the FAA and the Montana SHPO can be found in Appendix A.
Tracts 4-A and 4-B, which are proposed for acquisition by the Sponsor under the Proposed Action, are privately-owned residential tracts at the southeast edge of the airport property. Tract 4-A consists of vacant and unimproved subdivision land. Tract 4-B is an improved tract with a residence and out buildings. The portion of the Tract 4-B affected by the proposed improvements at EKS has been highly disturbed due to residential access road and parking area development and surface grading. A cultural resource survey was conducted on Tract 4-B on June 10, 2019; however, the landowner for Tract 4-A was unwilling to allow access to the property for a survey. If the property is acquired under the Proposed Action, Tract 4-A will be surveyed prior to any disturbance.
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Figure 5‐1 shows the portions of Tracts 4-A and 4-B proposed for acquisition and existing development on the properties.
Since the lands acquired from Tracts 4-A and 4-B would serve as part of the expanded OFA for the runway, no airport infrastructure is proposed on these properties. The only project-related activities proposed for these tracts include the removal of existing airport boundary fencing and installation of new fencing along the revised airport boundary. The previously disturbed areas within Tract 4-B may be reclaimed with topsoil, seed, fertilizer and mulch to aid in long term erosion protection and weed control. Mitigation No mitigation measures are required or proposed for the Proposed Action since it was determined there will be no historic properties adversely affected due to the improvements at EKS.
A Cultural Resource Inventory will be completed on the new acquisition area in Tract 4-A prior to any ground disturbing activities within the parcel.
If unanticipated historic properties, cultural materials or human remains are discovered during construction, all related construction activities would immediately cease within 150 feet of the discovery and the Airport Sponsor would immediately notify the FAA. The FAA would then determine what action should be taken to resolve any adverse effects. The FAA would also notify the SHPO/THPO and any Tribe that might attach religious and cultural significance to the affected property, and, if necessary, the ACHP, within 48 hours of discovery. The notification would describe the actions proposed by the FAA to resolve the adverse effects. The SHPO/THPO and the Tribe shall respond within 48 hours of notification and the FAA would take into account their recommendations and carry out appropriate actions. Conclusion The Granger Ditch is the only NRHP-eligible historic property that exists at or near the Ennis Big Sky Airport. Based on an analysis of potential impacts, the FAA determined the Proposed Action would have no direct or indirect effects on this historic irrigation ditch because it is not within the area affected by the proposed improvements. The FAA made a finding of No Historic Properties Adversely Affected and submitted the finding to the Montana SHPO on March 15, 2018. The Montana SHPO concurred with the No Historic Properties Adversely Affected determination on April 2, 2018. Therefore, implementing the Proposed Action will not result in any impacts to historic resources.
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Figure 5-1: Existing Development on Tracts 4-A and 4-B
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5.10 Visual Effects (Including Light Emissions) FAA Order 1050.1F does not present a threshold for significant impacts associated with light emissions and visual effects. The FAA guidance suggests that impacts may occur when an action’s light emissions create annoyance or interfere with normal activities or adversely affect the visual character of the area.
Light emission impacts are typically related to the extent to which any lighting or glare associated with the proposed action or alternatives would create an annoyance for people in the vicinity and/or would interfere with their normal activities, including work and recreation. Impacts to visual resources and visual character are typically related to a decrease in the aesthetic quality of an area resulting from development, construction, or demolition. Impacts result if a proposed action would affect, obstruct, substantially alter, or remove visually important or unique resources like buildings, historic sites, or other landscape features (topography, water bodies, or vegetation). Direct and Indirect Impacts Sources of lighting at EKS currently include a radio-controlled Medium Intensity Runway Lighting (MIRL) system, guidance signs, “two-box” PAPIs near the runway ends, a lighted windcone and segmented circle, an airfield beacon, obstruction lighting atop the AWOS tower, task and security lighting at airport buildings, and operational lights on aircraft using the facility. Visual resources near the airport consist of mountain peaks, foothills and open grassland areas, agricultural lands, corridors for local roads, and scattered rural residences.
No Action Alternative There are no lighting improvements proposed with the No Action Alternative with no new light emissions or visual impacts at the Ennis Big Sky Airport. The existing light sources associated with aviation facilities and aircraft operations would continue. Airport operations and maintenance activities would not be expected to cause any new visual or aesthetic effects.
Proposed Action Improvements to the lighting systems and NAVAIDS at EKS are necessary with the Proposed Action. In conjunction with the proposed modifications to Runway 16/34, revisions must be made to the MIRL system for the runway. The existing MIRL system along the east side of the runway must be relocated to accommodate the planned widening of the runway. The MIRL system must also be extended northward along both sides of the proposed runway extension.
Either one or both of the PAPIs for Runway 16/34 would be relocated due to runway widening and lengthening. The Runway 16 PAPI equipment needs to be relocated based on the future threshold location. The Runway 34 PAPI equipment may be able to remain in place, although adjustments may be necessary based on shoulder grading and any runway profile changes. Both PAPI’s would be expanded to “four-box” systems.
EKS currently has taxiway reflectors in lieu of taxiway lighting, with dual taxiway lights delineating the taxiway-runway intersections. The Proposed Action would replace the existing reflectors with taxiway lights and install new lighting along the length of the proposed full-length parallel taxiway. Guidance signs would also be installed at the new Runway 16 turnaround.
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This alternative would relocate the wind cone, segmented circle, and AWOS III/P to newly acquired property on the east side of the airport beyond the new C-II-5000 OFA for Runway 16/34. The beacon at the airport would also be moved to a new site west of its current location to facilitate ultimate terminal area improvements.
Since these lighting improvements would primarily be replacements for the existing lighting systems, no substantial impacts relating to light emissions are anticipated from airport development for the Proposed Action. The addition of taxiway lighting represents a visual change; however, taxiway lights would not be out of context with the surrounding airport environment. Light emissions from aircraft operations would not substantially change since approach or departure procedures would remain similar to existing conditions. Future development of hangars, airport buildings, and other features may incrementally add other lights to the facility and slightly change the visual appearance of the airfield.
The airport’s location on an alluvial fan requires substantial earthwork to extend Runway 16/34 to the north at the required grade, reconstruct and widen existing sections of the runway, and extend the parallel taxiway to the end of Runway 16. Excavation (cuts) may approach 20 feet deep in some areas and extensive grading work is required to provide runway and taxiway safety areas and ensure clear airspace surfaces. The required earthmoving and grading would cause changes to the landscape immediately adjoining EKS and result in some visual impacts. Mitigation No mitigation measures are required or proposed for the Proposed Action since it was determined light emissions at EKS would change little over existing conditions or not be out of context in an airport environment.
The excavation required to extend the runway northward would cause a notable visual change for lands around the airport, particularly during construction when excavation and grading activities result in surface disturbances and the loss of grassland vegetation. However, with appropriate mitigation, the planned airport improvements would not adversely affect the overall visual character of lands around EKS or the broader landscape of the Madison Valley.
Visual impacts associated with the construction of the Proposed Action would be minimized by designing slopes in a manner that avoids sharp breaks in grades and blends new slopes into the adjoining terrain. Areas disturbed during construction would be promptly seeded with species compatible with airport operations and the adjoining grasslands to help minimize erosion. After successful revegetation, areas adjoining the new runway and parallel taxiway would appear similar to those on the remainder of the airport property. The character, materials, and appearance of the extended and widened runway and full-length parallel taxiway would be similar to that of the existing facilities. Conclusion No significant light emissions or visual impacts would be expected with the implementation of the Proposed Action. The proposed lighting improvements would primarily be replacements for existing lighting systems or new lighting features compatible with surrounding uses. An airport has existed at the same location since the 1970s and comparable airport lighting features have been
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5. ENVIRONMENTAL CONSEQUENCES ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT present in this area for many decades. The new or modified lighting installations associated with the Proposed Action are not anticipated to create an annoyance among people or interfere with normal activities and would not be out of character with the existing facilities.
Visual changes to the landscape around at and near the airport would result from the required vegetation clearing, earthmoving, and grading necessary to construct some airport improvements. These changes would be most noticeable during construction and immediately following when disturbed lands have not yet revegetated. After successful revegetation, the airport would have an appearance similar to that of the existing facility.
For these reasons discussed above, no significant light emissions or visual impacts would be expected. 5.11 Natural Resources and Energy Supply Impacts on the energy supply and natural resources may occur if changes in the stationary facilities at the airport cause a measurable effect on local supplies of energy, if the proposed action causes increased consumption of fuel by aircraft and ground vehicles, or if unusual materials that are in short supply are needed for the proposed airport improvements.
Consistent with EO 13693, Planning for Federal Sustainability in the Next Decade, FAA policy encourages conservation of natural resources and energy along with the use of renewable energy sources in the development of new aviation facilities. FAA Order 1050.1F does not establish a specific significance threshold for natural resources and energy supply impacts but suggests impacts may occur when the potential demands of an action exceed available or future supplies of natural resource or energy. Direct and Indirect Impacts No Action Alternative No construction activities would occur with the No Action Alternative, so no impacts to natural resources and energy supply are anticipated.
Incremental increases in aviation activity and associated consumption of aviation fuel are expected at EKS in the future even if improvements are not made at the facility. This conclusion is based on analyses and forecasts of future aviation activity presented in the 2018 Master Plan Update for the airport. The No Action Alternative would not cause notable changes in the use of energy for stationary facilities or maintenance equipment and would not require the use of any scarce natural resources.
Proposed Action As noted above, the 2018 Master Plan Update supports forecasts for incremental increases in aviation activity at EKS to occur with or without improvements at the airport. Increased fuel consumption would be proportional to future growth in aviation activity.
Extending and widening the runway, reconstructing sections of the existing runway, providing a full-length parallel taxiway, reconstructing the south apron, constructing Taxilane C (extension)
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5. ENVIRONMENTAL CONSEQUENCES ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT and D, and developing private hangars along Taxilanes C and D as proposed would consume energy during construction to power construction vehicles and equipment. Long term, minor increases in energy use would occur due to the increased distance aircraft would have to taxi between the end of Runway 16 to aircraft parking areas and hangars. No increased consumption of fuel from air or ground vehicles is anticipated that would produce a shortage in local fuel supplies.
Notable impacts to utilities are not anticipated with this alternative because principal utility infrastructure lies outside the project area. The additional lighting required for the extended runway would slightly increase the amount of energy required for airport operations.
No impacts are anticipated to scarce mineral resources or other consumable construction materials. Mitigation No mitigation measures are necessary or proposed. Conclusion No significant impact to natural resources and energy supply is anticipated as a result of the implementation of the Proposed Action. This conclusion was reached because the construction, operation, and maintenance requirements of the action would not be expected to cause demands exceeding the available or future supplies of natural resources or energy. 5.12 Climate FAA Order 1050.1F does not provide a significance threshold for assessing impacts on the global climate. Although there are no federal standards for aviation-related GHG emissions, it is well- established that GHG emissions can affect climate.2 The CEQ has indicated that climate should be considered in NEPA analyses. As noted by CEQ, however, “the totality of climate change impacts is not attributable to any single action but are exacerbated by a series of actions including actions taken pursuant to decisions of the Federal Government.…. emissions from a proposed Federal action represent only a small fraction of global emissions is essentially a statement about the nature of the climate change challenge and is not an appropriate basis for deciding whether or to what extent to consider climate change impacts under NEPA.”3 GHG Emissions Assessment FAA guidance indicates that if a project could alter criteria pollutants, it has the potential to affect GHG emissions. The same modeling tools used in preparing the previous criteria pollutant emissions inventories were used to prepare the GHG inventory. The emissions of GHGs were projected for future years 2022 and 2027 for the No Action Alternative and the Proposed Action.
2 See Massachusetts v. E.P.A., 549 U.S. 497,521-23 (2007). 3 Final Guidance for Federal Departments and Agencies on Consideration of Greenhouse Gas Emissions and the Effects of Climate Change in National Environmental Policy Act Reviews, CEQ, (August 1, 2016).
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Table 5.4 presents the projected emissions of GHGs for the alternatives under consideration at
EKS. The emissions are shown in units of metric tons of CO2 (MT CO2). Additional information about GHGs and the methodology used to project GHG emissions is provided in the Air Quality Assessment found in Appendix F of the EA.
Under the Proposed Action, the emissions of CO2 would be above those projected for the No Action Alternative due to the increase in taxi time for aircraft using a longer runway at a slightly different location on the airport property. The GHG emissions for the Proposed Action were projected to be
86 MT and 22 MT CO2 higher than for the No Action Alternative, respectively, in 2022 and 2027. These emissions represent increases of about 14% and about 4%, respectively, over estimated GHG emissions for the No Action Alternative in 2022 and 2027. In the context of global emissions, the project-related increase in GHG emissions would not be significant.
Table 5.4: Estimated GHG Emissions GHG Emissions Difference from YEAR ALTERNATIVE (MT CO2) No-Action (MT CO2) No Action Alternative 528 N/A 2022 Proposed Action 606 86 No Action Alternative 556 N/A 2027 Proposed Action 578 22
N/A – Not Applicable Source: BridgeNet International using AEDT, Synergy Consultants using ACEIT. March 2018. Mitigation No mitigation is required or proposed because the project-related increase in GHG emissions is negligible when compared to the amount of global GHG emissions. Conclusion The FAA has not identified significance thresholds for aviation GHG emissions nor has the agency identified specific factors to consider in making a significance determination for GHG emissions. The implementation of the Proposed Action, as shown by Table 5.4 would produce an estimated
606 metric tons of CO2 in 2022 (and 578 metric tons of CO2 in 2027) once the project becomes fully operational with the proposed improvements in place. This represents an extremely small percentage of global GHG emissions. Therefore, there would be no significant increase in greenhouse gas emissions as a result of the Proposed Action. 5.13 Noise and Compatible Land Use Aircraft noise exposure is typically evaluated based on the compatibility of the lands that are exposed to various noise levels. The FAA’s established land use compatibility guidelines relative to certain DNL noise levels are presented in 14 CFR Part 150. Most land uses are compatible with aircraft noise that does not exceed DNL 65 dB, although Part 150 declares that “acceptable” sound levels should be subject to local conditions and community decisions. Nevertheless, DNL 65 dB is generally identified as the threshold level of aviation noise which is “significant.”
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FAA Order 1050.1F states that when evaluating a project, the threshold when the project-related noise become significant, compared to the No Action Alternative for the same timeframe, would cause noise sensitive areas located at or above DNL 65 to experience a noise increase of at least DNL 1.5 dBA. If a project-related change would cause a DNL 1.5 dB increase to a noise sensitive land use within the DNL 65 dB contour, then FAA guidance suggest that noise out to DNL 45 dB should be assessed to disclose if a DNL 5 dB increase would occur between DNL 45-60 dB, or a DNL 3 dB increase would occur within DNL 60-65 dB contour. Therefore, an analysis was conducted using the AEDT model to help determine whether the Proposed Actions could result in a significant impact per FAA guidance.
Appendix F documents the assumptions used in preparing noise contours with the AEDT model. Contours for year 2022 were prepared, the first full year of operation with the proposed development actions in place, as well as 5 years after (2027). Contours showing DNL 65 dB and greater sound level were prepared. The impact of aircraft noise levels upon land and land use surrounding EKS is presented in the following sections. Direct and Indirect Noise Impacts No Action Alternative The DNL 65 dB contour for EKS currently encompasses an area of about 147 acres centered on the runway. The DNL 65 dB contour generally falls on airport property east and west of the runway; however, the contour widens from the south to the north and extends beyond the existing airport property. At the southern end, the DNL 65 dB contour is between the runway and W Belanca and extends slightly south of Runway 34. At about W Waco Lane on the west, the contour falls between an off-airport hangar and the runway. On the east side of the airfield, the contour falls about 300 feet off airport property over undeveloped land at E Waco Lane. At the northern end of the airfield, the contour extends about 900 feet to each side of the runway centerline at its widest point.
The area within the DNL 65 dB contour consists primarily of airport lands but also extends beyond the existing airport property to encompass vacant lands in the Shining Mountains Airpark Subdivision and grazing lands located north and east of the airport on State of Montana land and the Longhorn Ranch. There are no residences or other noise sensitive receptors within the DNL 65 dB or higher noise contours. The DNL 65 dB noise contour does not fall on Beaverhead-Deerlodge National Forest land since these public lands are located at least 1.5 miles or more from the airport.
Figures 5‐2 and 5‐3 show noise exposure contours for future conditions under the No Action Alternative. Year 2022 is the anticipated first full year of operation of the improved airport and Year 2027 represents operating conditions 5 years beyond the airport’s opening operational period. There are no noise sensitive or incompatible land uses within the 65 DNL contour for either future year.
By 2022 and 2027, the area within the DNL 65 dB noise exposure contour would be expected to increase from its 2015 condition of 147 acres to nearly 153 acres by 2022 and then nearly 156 acres by 2027, based on the forecast aircraft fleet and operations. No noise sensitive land uses would be located within the 2022 or 2027 DNL 65 dB noise contour for the No Action Alternative, as the contours would fall over airport lands or undeveloped lands adjacent to the airport.
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Table 5.5 summarizes the noise impact areas associated with the No Action Alternative.
Table 5.5: Noise Impact Areas – No Action Alternative Forecast Number of Annual Area Within DNL 65 dB NOISE ANALYSIS PERIOD Aircraft Operations Contour (Acres)* Base Year (2015) 12,200 147.0 Year 2022 13,130 152.6 Year 2027 13,596 155.6
Source: BridgeNet International, March 2018 * With 6,600’ long Runway 16/34
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Figure 5-2: Year 2022 Noise Contours – No Action Alternative
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Figure 5-3: Year 2027 Noise Contours – No Action Alternative
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Proposed Action With the Proposed Action the project activities noted in Chapter 1 would be completed. Most notably, the extension of the runway and development of the parallel taxiway are project activities that would affect aircraft noise at EKS. The runway extension is not expected to change runway use, but aircraft landing on Runway 16 or departing from Runway 16 would taxi to the new runway end. Figures 5‐4 and 5‐5 show the noise exposure contours for the Proposed Action.
Table 5.6 summarizes the potential noise impact areas associated with the Proposed Action. The 65 DNL contour with the Proposed Action would decrease by about 1.1 acre in 2022, upon completion of the runway extension. By 2027, as the aircraft fleet mix changes, the runway extension would decrease the area within the noise contour by about 0.4 acre. This decrease in noise exposure is a function of elongating the contour with the runway extension, which would narrow the contour along the eastern and western edges. Noise would be transferred north with the 1,000-foot-long runway extension. No incompatible or noise sensitive uses would occur within the 65 DNL with the Proposed Action in 2022 or 2027. While noise exposure conditions would change with this alternative, the changes in noise levels do not exceed the FAA’s thresholds of significance.
Table 5.6: Noise Impact Areas – Proposed Action Change in Area Area Within Area Within Within DNL 65 dB NOISE ANALYSIS Forecast Number DNL 65 dB Contour DNL 65 dB Contour Contour PERIOD of Annual Aircraft No Action With Project Relative to No Operations (Acres) (Acres) Action (Acres) Base Year (2015) 12,200 147.0 N/A N/A Year 2022 13,130 152.6 151.5 (1.1) Year 2027 13,596 155.6 155.2 (0.4)
Figures 5‐6 and 5‐7 compare the modeled 65 DNL contour associated the Proposed Action to the No Action Alternative for future years 2022 and 2027, respectively.
During construction, increases in noise levels would occur due to the operation of construction equipment. These increases would be temporary and localized to work locations within the project area. These temporary impacts and their degree of adversity would decrease as construction activities are completed. At EKS, work areas would generally be located well away from the residences in the area.
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Figure 5-4: Year 2022 Noise Contours – Proposed Action
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Figure 5-5: Year 2027 Noise Contours – Proposed Action
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Figure 5-6: 2022 Noise Contour Comparison – Proposed Action and the No Action Alternative
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Figure 5-7: 2027 Noise Contour Comparison – Proposed Action and the No Action Alternative
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Mitigation No noise mitigation is required. The County has considered voluntary noise abatement plans in the past in the form of suggested traffic patterns to minimize noise impacts associated with flight activities at EKS. However, since there are many variables like wind, clouds, other traffic, pilot / aircraft capabilities and established norms, these can only be requests or suggestions with the ultimate decision lying with the pilot in command and based on safety.
For those areas not in immediate control of the airport, AAA regulations have been implemented for EKS to help prevent future non-compatible land use – including development of noise sensitive areas within the 65 DNL contour. Madison County would modify its AAA regulations for EKS to recognize the proposed northerly extension of Runway 16/34, the 12.5-foot shift to the east in the runway centerline, and dimensional changes in airspace required by the proposed transition from a B-II-5000 to C-II-5000 airport (and 14 CFR Part 77 surfaces for >12,500-lbs aircraft with >3/4-mile visibility minimums). This would require modifications to the map showing the AAA and revising the associated regulations as appropriate. The updated ALP set for the proposed facility would also need to be incorporated into the AAA regulations for EKS.
Measures to mitigate for noise impacts during construction would include limiting work to reasonable daily hours and ensuring construction equipment is in good working order with mufflers whenever possible. Conclusion No significant noise impacts are anticipated with the Proposed Action. This conclusion is based on the results of AEDT noise modeling that shows the area contained within the 65 DNL noise exposure contour would not contain any residences or other noise sensitive land uses. 5.14 Socioeconomics, Environmental Justice, and Children’s Environmental Health and Safety Risks FAA Order 1050.1F requires an evaluation of proposed airport development actions to determine if they would cause socioeconomic impacts, environmental justice impacts, or pose health and safety risks to children. The FAA has not established significance thresholds for each of these considerations but has identified the following factors to be considered during the evaluation of potential impacts.
Socioeconomic Impacts: When an action has the potential to:
Induce substantial economic growth in an area, either directly or indirectly; Disrupt or divide the physical arrangement of an established community; Cause extensive relocation when sufficient replacement housing is unavailable; Cause extensive relocation of community businesses that would cause severe economic hardship for affected communities; Disrupt local traffic patterns and substantially reduce the levels of service of roads serving the airport and its surrounding communities; or Produce a substantial change in community tax base.
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Environmental Justice: When an action would have the potential to lead to disproportionately high and adverse impact to an environmental justice population (i.e., a low-income population or minority population) due to:
Significant impacts in other environmental impact categories; or Impacts on the physical or natural environment that affect an environmental justice population in a way the FAA determines are unique and significant to that population.
Children’s Environmental Health and Safety Risks: When an action would:
Have the potential to lead to a disproportionate health and safety risk to children. Potential Impacts Chapter 4 of the EA included a review of the socioeconomic and demographic conditions found within the project area. The review relied upon information from the 2012‐2016 American Community Survey (ACS) to establish the socioeconomic characteristics and the race and ethnicity characteristics of the populations for the State of Montana, Madison County, and County Census Tract 1 which includes EKS.
No Action Alternative The No Action Alternative would not require any new property or displace any residents or businesses. Consequently, there would be no change to the tax base in Madison County. Local traffic patterns and service levels on roads used to access the airport would not change.
There are no induced socio-economic impacts associated with taking no action to improve the Ennis Big Sky Airport. The alternative would have no effect on patterns of population movement and growth, public service demands, or business and economic activity in the Ennis area or broader Madison Valley.
The No Action Alternative would not have a disproportionate adverse impact on minorities or low- income populations because such populations do not exist near the airport.
There are no hospitals, assisted living facilities, churches, or schools near the airport. The nearest such facilities are in the Town of Ennis located about 7 miles from the airport. The continued use of existing airport would not pose any risks to children’s environmental health and safety.
Proposed Action The implementation of the Proposed Action would not cause major shifts in the patterns of population movement and growth, extensive demands for public services, or substantial changes in business or economic activity. The population growth and development seen in Madison County over the past three decades have primarily been driven by outdoor recreation and vacation activities and not by aviation activity or aviation-related development at the airport. This alternative would not substantially change the demand for public services like law enforcement, fire protection, or emergency medical services.
Increased aviation operations are forecasted at EKS with or without improvements at the airport.
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Implementing the Proposed Action would enhance airport operations and safety by providing a longer and wider runway and other facility changes to meet FAA design standards for the critical aircraft. These improvements would better accommodate the critical aircraft and entire aircraft fleet that now uses and is forecasted to use EKS over the foreseeable future. The improvements included with the Proposed Action could also indirectly contribute to additional revenue or new business growth at the airport through the provision of additional space for hangar development.
The implementation of the Proposed Action could account for an estimated $14.92 million of direct capital expenditures for construction improvements at the airport (estimate from Section 3.5.2 in Chapter 3). Temporary beneficial economic impacts are also foreseen during the construction of the proposed airport improvements associated with this alternative. These beneficial impacts include not only jobs, wages, and expenditures during construction of the airport improvements at EKS, but the additional indirect expenditures by construction workers needing food, lodging, and recreation within Madison County and Ennis area.
The Proposed Action requires the fee acquisition of 3.17 acres of private land adjoining the airport and securing a perpetual easement on 17.82 acres of land owned by the State of Montana. The acquisition of privately-owned land for this alternative would remove 3.17 acres from the property tax base of the County. This loss in tax revenue would be minor since the private land needed for airport development consists of undeveloped or lightly developed areas within large (typically 6.4 acres in size) rural residential parcels.
The Proposed Action would not require the relocation of any residents or businesses from lands needed to implement the airport improvements.
Facility operation and maintenance costs are not expected to increase notably due to the implementation of the Proposed Action. The cost of preventative pavement maintenance and other routine maintenance actions (snow removal, mowing, fencing, electrical systems, etc.) would increase slightly due to the increased size of the airport and some of its associated features.
Implementing the Proposed Action would require the airport to be closed during multiple phases of project improvements. The airport would generally remain in service during construction activities although short-term closures may be necessary for work in proximity to the existing runway. Much of the earthwork within the runway extension and approach area can be completed in advance with limited runway closures. Minor closures and impacts are anticipated as part of miscellaneous improvements such as reconstruction of the south apron and developing a full-length parallel taxiway, and construction of Taxilane C extension and Taxilane D. Extended closures will be required as part of the runway extension, widening, reconstruction of portions of the existing runway, and airspace grading improvements. It is desirable to complete this work in the Spring or early Summer, in attempt to avoid the busier traffic season at EKS which begins in July and extends through September. This would minimize adverse effects to the FBO business at the airport.
Local traffic patterns and service levels on roads used to access EKS would not change; however, traffic could increase slightly during construction due to workers and equipment traveling to and from the airport site.
Airport Road would fall within the RPZ for Runway 34 with the Proposed Action. The larger RPZ
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5. ENVIRONMENTAL CONSEQUENCES ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT overlays approximately 850 feet of the road. Airport Road is an unpaved public road accessing the entrance to the airport and providing exclusive use by residents of the Shining Mountains Air Park and the Mustang Ranches subdivision further to the east. Airport Road supports approximately 100 residential lots, although about two-thirds are currently undeveloped. The FAA has previously concurred that a detailed RPZ analysis was not warranted as part of the 2018 Master Plan development, due to the low traffic counts and the typical use (residential access) of this public roadway versus the estimated costs for the County to acquire land, a portion of which is in a conservation easement, and divert the road around the RPZ.
The ACS Profile Report for the 2012-2016 period reviewed for this analysis does not indicate the presence of either minority or low-income populations residing near the airport. For this reason, no environmental justice impacts are foreseen with the Proposed Action.
There are no hospitals, assisted living facilities, churches, or schools near the airport. The nearest such facilities are in the Town of Ennis located about 7 miles from the airport. For these reasons, no risks to children’s environmental health and safety are anticipated with the Proposed Action. Mitigation Land acquisition necessary for any federally-assisted airport development would be accomplished in accordance with the Uniform Relocation Assistance and Real Property Acquisition Policies Act of 1970 (Uniform Act). The Uniform Act prescribes procedures to ensure fair and consistent acquisition of real property for Federal programs and provides additional benefits and entitlements for persons who are displaced due to the acquisition of their owned or leased occupied property for an AIP-assisted project.
FAA Advisory Circular Land Acquisition and Relocation Assistance for Airport Improvement Program Assisted Projects (AC 150/5100-17) provides procedural guidance to airport sponsors to help carry out acquisition and relocation programs in conformance to the Uniform Act. Typical prerequisites for land acquisition include:
Developing property exhibit maps for the airport illustrating land needs; Land title verification by the sponsor (airport); Investigation of hazardous materials and contamination including completion of an EDDA; Preparation of a relocation plan if needed; Appraisals by a federally qualified appraiser and review appraiser to establish a fair market value of the real property to be acquired; and Providing a written offer to the property owner in accordance with the appraised value of the property and negotiating a purchase price.
Should it be necessary, the sponsor is required under the Uniform Act to provide an adequate relocation assistance program that ensures the prompt and equitable relocation and reestablishment of persons displaced due to its federally assisted airport projects. However, no residential or business relocations would occur due to the proposed improvements at EKS.
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All necessary closures for construction activities at EKS would be determined during final design activities and would be coordinated with Madison County, the Madison County Airport Board, the FBO, and all hangar tenants or based aircraft owners. Conclusion Implementing the Proposed Action will not induce substantial economic growth to the Town of Ennis or the Madison Valley area, disrupt or divide any communities, require residential or commercial relocations, or disrupt traffic patterns on roads serving EKS. The proposed improvements will not affect any environmental justice populations or result in significant related effects on air, water, and other natural systems that may adversely affect such populations. Likewise, no conditions increasing the health and safety risks to children were identified due to the implementation of the Proposed Action. 5.15 Water Resources FAA Order 1050.1F indicates significance thresholds for impacts to surface and groundwater resources would be met if the proposed action results in exceedances of water quality standards established by Federal, state, local, and tribal regulatory agencies or contamination of a public water supplies (surface water or aquifer) such that public health may be adversely affected. The Order identifies a variety of considerations that must be considered including if an action has the potential for substantial degradation of water quality, water quality problems that cannot be avoided or mitigated, or if water quality permits or authorizations would be difficult to obtain. Direct and Indirect Impacts to Surface Waters Four intermittent drainages—McDeed Creek, Boulder Creek, and two unnamed tributaries to Boulder Creek—exist in the project area. McDeed Creek, Boulder Creek, and two unnamed tributaries of Boulder Creek are culverted under the existing runway and partial parallel taxiway. The Granger Ditch, an irrigation supply canal which crosses the western portion of the existing airport property, does not appear to regularly convey any flows.
No public water supplies or waters of national significance are in the project area.
No Action Alternative The No Action Alternative does not include any new airport development actions. Therefore, this alternative would not result in any new direct or indirect effects on McDeed Creek, Boulder Creek and two of its unnamed tributaries, or the Granger Ditch.
Proposed Action The runway extension, widening to the east, and safety area expansions associated with the Proposed Action would require work in McDeed Creek to modify or replace culverts and perpetuate surface drainage. The 2008 runway extension project at EKS installed skewed, 36-inch reinforced concrete pipe arch (RCPA) culverts beneath the runway and parallel taxiway area at the end of the runway in McDeed Creek. Additionally, a channel change of about 1,370 feet in length was constructed along the same reach of McDeed Creek that would be affected by the proposed culvert replacement work associated with the Proposed Action. The McDeed Creek channel was typically
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5. ENVIRONMENTAL CONSEQUENCES ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT constructed with 3:1 side slopes and a 4-foot-wide flat bottom. Three reaches of the reconstructed channel with gradients exceeding 5% were riprapped.
The Proposed Action would remove and replace the two existing RCPA culverts for McDeed Creek beneath the “16” end of the runway and the parallel taxiway area with one long culvert. The longer culvert is necessary to ensure the ends of the culvert and associated drainage channel are not located within the Runway Safety Area (RSA) and Taxiway Safety Area (TSA) for the proposed C-II- 5000 facility. FAA Advisory Circular 150/5300-13 requires RSAs and TSAs to be “cleared and graded, and have no potentially hazardous ruts, humps, depressions, or other surface variations.” Figure 5‐8 shows work required in the McDeed Creek drainage.
Figure 5-8: Proposed Work in McDeed Creek
The proposed culvert installation requires modifications to the previously rebuilt McDeed Creek channel to direct surface drainage to the new culvert inlet and construction of a new channel from the outlet of the new culvert to the existing McDeed Creek channel. Abandoned sections of the previously reconstructed channel would be filled, graded, and revegetated after construction of the proposed improvements.
Thirty-inch diameter RCP culverts cross beneath Runway 16/34 and the parallel taxiway north and south of Taxiway A-3 and near the north end of the existing parallel taxiway to convey seasonal drainage from two unnamed tributaries of Boulder Creek and from Boulder Creek. The proposed improvements would remove the existing culverts beneath the runway and parallel taxiway and replace them with a single long culvert extending beyond the new RSA and TSA at each location. Short sections of open channel between the runway and taxiway culverts in each drainage would be
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5. ENVIRONMENTAL CONSEQUENCES ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT eliminated and the ground surface graded and revegetated. Minor channel modifications may be required to ensure the new culverts maintain stream gradients and adequately direct flow paths. Figure 5‐9 shows the proposed locations for new culvert installations.
Unnamed Tributary #1 Boulder Creek
Taxiway A-3
Boulder Creek
Figure 5-9: Proposed Culvert Replacement Areas in Boulder Creek and Its Tributaries
The Proposed Action would not require work in or near the Granger Ditch.
Construction of the Proposed Action would increase the amount of impervious area over current conditions due to the extension of the paved runway, runway widening, the development of a full- length parallel taxiway, new taxilane construction, new hangar construction, and modifications to apron areas. The additional paved surface area would result in more surface water runoff from paved surfaces than currently seen at the airport. New storm water management features to be constructed as part of the Proposed Action would be consistent with the types and methods currently in use at EKS. Runoff from the new airfield pavements would generally be collected and retained on airport property for infiltration or conveyed via shallow ditches to existing surface drainages.
Construction activities may cause temporary and localized impacts to water quality. These impacts are typically associated with erosion from disturbed areas and/or work within surface waters.
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Mitigation for Impacts to Surface Waters and Water Quality Water quality would be maintained through the process of obtaining necessary water-related permits, adhering to permit conditions, and by using Best Management Practices (BMPs) during construction activities for the Proposed Action. A variety of federal and state approvals or permits may be needed prior to undertaking construction activities in addition to the appropriate FAA authorizations. Table 5.7 lists potentially applicable water-related permitting and regulatory requirements for the proposed improvement project at EKS.
Work within McDeed Creek, Boulder Creek and two of its unnamed tributaries on the airport property will require several water-related permits prior to construction including a CWA Section 404 permit from the COE and a SPA 124 permit from the MFWP to comply with the Montana Stream Protection Act.
Coordination with the Montana Regulatory Office of the COE regarding the proposed improvements at EKS was initiated on February 22, 2018 when the COE was contacted for its initial comments on the project. The COE responded on March 15, 2018 and noted the project may affect jurisdictional aquatic resources and require a Section 404 permit and potentially, mitigation for impacts to aquatic resources. The appropriate type of Section 404 permit (Nationwide or Individual) and any specific mitigation requirements, will be determined during the Section 404 permitting process.
Additional coordination with the COE on April 2, 2018 indicates the proposed improvements at EKS require a Section 404 Individual Permit because anticipated impacts to McDeed Creek and Boulder Creek and its tributaries would exceed 300 linear feet. According to the Montana Stream Mitigation Procedure (MTSMP) approved by the COE in February 2013, projects resulting in more than 300 linear feet of new impact on streams usually require compensatory mitigation. Additionally, projects resulting in 150 linear feet of stream or more being placed into a new culvert or pipe, and projects extending existing culverts or pipes by 150 linear feet or more, require compensatory mitigation. Both of these mitigation thresholds would be exceeded with the implementation of the Proposed Action. Therefore, mitigation for stream impacts in the same watershed would be required.
Copies of relevant correspondence from the COE can be found in Appendix A of the EA.
A SPA 124 Permit will be required due to anticipated project impacts associated with work in McDeed Creek, Boulder Creek and two unnamed tributaries to Boulder Creek. A 318 Authorization for construction activities that may cause short term or temporary violations of state surface water quality standards for turbidity must also be obtained prior to initiating construction. The 318 Authorization may be obtained from the MDEQ or may be waived by MFWP during its review process for granting a SPA 124 Permit.
Applications for a Section 404 permit, a SPA 124 Permit, and a 318 Authorization would be prepared after completion of the NEPA process when detailed plans for the design of airport improvements at EKS have been produced. This would enable final impacts to wetland and stream habitat to be determined with a high level of accuracy based on a detailed topographic survey of the project area. Permit approval documents will specify conditions that must be followed during construction to help protect water quality.
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Table 5.7: Water-Related Permits and Approvals Needed for Airport Construction at EKS
Permit/Approval Regulatory Requirement Entity Description Clean Water Act Department of This permit is required for a project results in the discharge Section 404 Permit the Army Corps or placement of dredged or fill material into waters of the (Individual Permit) of Engineers United States. Waters of the United States include lakes, (COE) rivers, streams (including intermittent streams and tributaries), wetlands, and other aquatic sites.
Impacts to McDeed and Boulder Creeks and two unnamed tributaries to Boulder Creek would need to be quantified and mitigated as necessary based on the COE’s 2013 Montana Stream Mitigation Procedure (MTSMP). The placement of fill in delineated wetlands along McDeed Creek would be subject to authorization under Section 404. Montana Pollution Montana This permit is required for construction activity which results Discharge Department of in the “disturbance” of equal to or greater than one acre of Elimination System Environmental total land area will need to obtain permit coverage. (MPDES) Quality (MDEQ) Construction activity includes the disturbance of less than General Permit for one acre of total land area that is part of a “larger Storm Water common plan of development or sale” if the larger common Discharges Associated plan will ultimately disturb one acre or more. with Construction Activity The improvements at EKS would disturb more than 1 acre. Montana Stream Montana Fish This permit is required for any agency or subdivision of Protection Act Wildlife & Parks federal, state, county, or city government proposing a (SPA 124 Permit) (MFWP) project that may affect the bed or banks of any stream in Montana. Any project including the construction of new facilities or the modification, operation, and maintenance of an existing facility that may affect the natural existing shape and form of any stream or its banks or tributaries is subject to the permit requirement.
The permit may be required for work within McDeed and Boulder Creeks and two unnamed tributaries to Boulder Creek. Short-term Turbidity Montana This permit required for any person, agency, or entity, Standard Department of either public or private, initiating a short-term activity that (318 Permit) Environmental may cause unavoidable short-term violations of state Quality (MDEQ) surface water quality standards. The major application of this law is related to sediments and turbidity caused by construction or other activities. The authorization may be obtained from the MDEQ or may be waived by MFWP during its review process under the Stream Protection Act (SPA 124 Permit).
Culvert extensions or installations would be designed to adequately convey projected stream flows and maintain or enhance existing stream channel conditions. Grading plans and storm water design would follow FAA standards for airfield construction.
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Since clearing, grading or excavation activities for any of the action alternatives under consideration would disturb more than 1 acre, a General Permit for Storm Water Discharges Associated with Construction Activity must be obtained from the MDEQ Permitting and Compliance Division. This permit requires the preparation of a SWPPP specifying BMPs to control erosion and restrict the transport of sediments to receiving waters. The MDEQ requires the Contractor to submit a complete Notice of Intent (NOI) package prior to beginning construction. If the NOI package is acceptable, the MDEQ will issue a confirmation letter indicating coverage by the General Permit allowing construction to be initiated. Implementation of erosion control measures would ensure that water quality in the area is protected.
The provisions of FAA Advisory Circular 150/5370-10F, Standards for Specifying Construction of Airports, (September 30, 2011), Item P-156, Temporary Air and Water Pollution, Soil Erosion, and Siltation Control, would be incorporated into the project specifications. Other FAA guidance concerning airport drainage, environmental enhancement, and construction controls would be evaluated for provisions that may be incorporated into the contract specifications to minimize the potential impacts of construction activities at EKS. Impacts to Floodplains No FEMA-designated floodplains or flood hazard areas or County-designated flood prone areas exist at EKS. Therefore, neither the No Action Alternative nor the Proposed Action would result in any impacts to floodplains. Direct and Indirect Impacts to Groundwater No source aquifers exist beneath the project area. The airport and rural residences in the area use groundwater as a domestic water source.
No Action Alternative The No Action Alternative does not include any new airport development actions. Therefore, this alternative would not result in any new direct effects on groundwater resources in the area. Contamination of groundwater could potentially occur due to a spill of hazardous substances associated with the operation or maintenance of aircraft or vehicles and airport maintenance activities.
Proposed Action Construction of the Proposed Action would not be expected to impact groundwater or groundwater flows in the project area. Information from the Montana Bureau of Mines and Geology Ground Water Information Center (GWIC) shows static water levels in most wells in the immediate area of EKS have static water levels at depths exceeding 120 feet. The maximum depths of excavation associated with this alternative are estimated to be about 20 feet. Prior work to extend the runway northward and numerous geotechnical borings on the airport have been completed to similar depths suggesting it would be unlikely to encounter groundwater during excavations to extend the runway as proposed with the Proposed Action.
As with the No Action Alternative, the potential exists for a spill of hazardous substances associated with aviation operations or maintenance activities that could contaminate groundwater.
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Mitigation for Impacts to Groundwater No mitigation is necessary or proposed since the proposed improvements are not expected to affect groundwater on or near the airport property.
A spill response plan is maintained at EKS by the FBO and a spill response kit would be available to all airport users. Hazardous material releases in excess of a reportable quantity would be reported to MDEQ and would be remediated to MDEQ specifications and standards. Such measures would effectively mitigate any releases of oil, grease, fuel, and other fluids from negatively impacting groundwater during airport operations. Direct and Indirect Impacts to Wetlands FAA Order 1050.1F lists the considerations or thresholds for identifying significant impacts to wetlands. A significant impact would occur when the airport action would:
Adversely affect a wetland’s function to protect the quality or quantity of municipal water supplies, including surface waters and sole source aquifers and other aquifers; Substantially alter the hydrology needed to sustain the affected wetland system’s values and functions or those of a wetland to which it is connected; Substantially reduce the affected wetland’s ability to retain floodwaters or storm runoff, thereby threatening public health, safety or welfare (the term welfare includes cultural, recreational, and scientific resources or property important to the public); Adversely affect the maintenance of natural systems supporting wildlife and fish habitat or economically important timber, food, or fiber resources of the affected or surrounding wetlands; Promote development of secondary activities or services that would cause the circumstances listed above to occur; or Be inconsistent with applicable state wetlands strategies.
One wetland site—a Palustrine Emergent (PEM) wetlands fringe along portions of McDeed Creek— was delineated within the project area during September 2016. These wetland areas are shown on Figure 4‐6 in Chapter 4. Wetlands were not identified along Boulder Creek or the two unnamed tributaries to Boulder Creek that cross the airport property. Typical runway and parallel taxiway grading requirements were used to establish preliminary construction limits. The areas of wetlands within the anticipated construction limits were summed to estimate the total area of wetlands impact along McDeed Creek. According to the COE, wetland impacts greater than 0.1 acres require mitigation within the same watershed.
No Action Alternative This alternative would maintain the current airport configuration and includes only the activities required to continue aviation operations and perpetuate existing facilities at EKS. These activities would not impact wetlands or other waters of the U.S. located on or adjacent to the airport property.
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Proposed Action This alternative would extend the existing runway 1,000 feet to the north, widen Runway 16/34 to the east, rehabilitate a portion of the existing runway, and provide a full-length parallel taxiway along the west side of the extended runway. These activities require removing the existing RCPA culverts beneath the runway and parallel taxiway area and installing a new culvert for McDeed Creek beneath the entire RSA and TSA. Minor channel modifications may be required for the culvert installations to maintain stream gradients and flow paths. Excavation and grading activities along the runway and parallel taxiway may also encroach on previously reconstructed sections of the McDeed Creek channel.
The Proposed Action would impact an estimated 0.06 acres of PEM wetlands along the fringes of McDeed Creek channel to extend and widen the runway and develop an extension to the parallel taxiway. Avoiding wetland impacts along McDeed Creek is not practicable because the wider and longer runway and full-length parallel taxiway need to be constructed at specific locations to provide an efficient airport layout and help ensure the safety of aircraft operations at the new C-II- 5000 facility. McDeed Creek and its associated wetlands run perpendicular to and cross the existing runway and area where the parallel taxiway would be built. For these reasons, encroachments on wetlands along the McDeed Creek are unavoidable.
The Proposed Action would not significantly impact wetlands at EKS based on a review of the FAA’s identified considerations or thresholds for significant impacts identified in FAA Order 1050.1F. This conclusion was reached for the following reasons:
The Proposed Action would not adversely affect a wetland’s function to protect the quality or quantity of municipal water supplies, including surface waters and sole source and other aquifers.
Seasonal runoff is the source of surface water in McDeed Creek and Boulder Creek and its unnamed tributaries. The water in these intermittent streams is not used as part of any municipal water supply. The Proposed Action would perpetuate surface water drainage conditions in McDeed Creek and Boulder Creek and its tributaries. As discussed in Sections 5.14.1 and 5.14.2, construction activities have the potential to cause temporary and localized impacts to water quality. However, the conditions associated with required water-related permits and measures to avoid or minimize erosion and control siltation from disturbed areas would help ensure surface water quality.
There are no sole source aquifers at EKS. The interactive web mapping application developed by the Montana Bureau of Mines and Geology Groundwater Information Center (GWIC) shows wells on and near EKS. This website shows numerous domestic wells on properties in the Shining Mountains Airpark Subdivision but only one domestic well location in the general area where the Runway 16/34 would be widened. The static water level in the well is listed at 127 feet according to the well log. The well location is about 5,000 feet south of McDeed Creek and its associated wetlands. The maximum depths of excavation associated with this alternative are estimated to be about 20 feet. Since the groundwater aquifers tapped by the wells near the airport exceed the anticipated depth of excavation for the proposed improvements, this alternative is not expected to inhibit recharges to area wells.
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The Proposed Action would not substantially alter the hydrology needed to sustain the affected wetland system’s values and functions or those of a wetland to which it is connected.
The proposed airport improvements would not substantially alter the hydrology, vegetation, or soils needed to sustain the functions and values of the affected wetlands along McDeed Creek. Seasonal surface water runoff is and will continue to be the primary sources of hydrology supporting fringe wetlands along McDeed Creek. The Proposed Action would perpetuate surface water drainage conditions in McDeed Creek. Wetlands appeared along McDeed Creek after channel changes were made during an airport improvement project at EKS in 2008. It is conceivable similar fringe wetlands may again develop along portions of McDeed Creek that are not within the new culvert after the implementation of the Proposed Action.
The Proposed Action would not substantially reduce the affected wetland’s ability to retain floodwaters or storm‐associated runoff, thereby threatening public health, safety or welfare.
The fringe wetlands along McDeed Creek do not retain floodwaters or attenuate storm water runoff in the area. FEMA has not delineated floodplains or flood hazard areas along McDeed Creek or Boulder Creek and its tributaries. Madison County has not identified any floodprone areas in the vicinity of the airport. Due to the widely dispersed residential development and agricultural use of lands surrounding the airport, there would be no heightened risk of flooding or associated increased threat to public health, safety or welfare from the implementation of the Proposed Action.
The Proposed Action would not adversely affect the maintenance of natural systems supporting wildlife and fish habitat or economically important timber, food, or fiber resources of the affected or surrounding wetlands.
McDeed Creek and other intermittent drainages crossing the airport property do not support fish. The lands on and immediately adjoining the airport property provide limited habitat for a variety of common wildlife species (generally small mammals and rodents) and birds associated with grassland habitats. As described in Section 5.6.5, the USFWS concluded implementation of the proposed airport improvements would not result in adverse effects to listed, proposed or candidate threatened or endangered species, or listed or proposed critical habitat.
Modified or new drainage structures on McDeed Creek, Boulder Creek, and two unnamed tributaries of Boulder Creek would be designed to adequately convey projected stream flows and to maintain similar stream channel conditions through the area. The proposed airport improvements would permanently eliminate some grassland habitat due to additional paving for the runway; however, this loss is viewed as minor given the amount of similar habitat that exists in the area. Once disturbed areas are revegetated at EKS, wildlife habitat conditions would be like those presently existing in the area.
Lands adjoining the airport are not cultivated for crops or timber. While livestock grazing occurs north of the existing airport, most of the immediately adjacent lands are part of a residential subdivision.
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The Proposed Action would not promote development of secondary activities or services that would cause the circumstances listed above to occur.
The potential for secondary (induced) impacts is discussed in Section 5.13.1.2 of this chapter. As discussed there, the proposed airport improvements would not cause major shifts in the patterns of population movement or growth, extensive demands for new public services, or substantial changes in business activity. For these reasons, the Proposed Action would not promote the development of secondary activities or services that would adversely impact wetlands in the area.
The Proposed Action would be consistent with applicable state wetland strategies.
Wetland strategies, goals and objectives for the State of Montana are elaborated in Priceless Resources: Strategic Framework for Wetland and Riparian Area Conservation and Restoration in Montana 2013‐2017 developed by the Montana Wetland Council. This Strategic Framework was approved by the Governor of Montana and the Directors of the MDEQ, DNRC, & DFWP as the state plan for wetlands and riparian areas.
Unavoidable wetland and stream impacts to McDeed Creek, Boulder Creek, and the two unnamed tributaries to Boulder Creek would be mitigated within the same watershed through the purchase of wetland and/or stream mitigation credits at the Upper Missouri Mitigation Bank or through Montana’s In Lieu Fee (ILF) Mitigation program. These are mitigation methods supported and endorsed by state and federal agencies including the MFWP, MDEQ, COE, and EPA. By implementing either of these mitigation strategies, no net loss of wetland acreage would occur in the watershed and compensation for stream impacts associated with the proposed improvement would be secured.
The anticipated wetland and stream mitigation is consistent with Montana’s wetland strategies since impacts will be mitigated within the same watershed.
Only Practicable Alternative Finding. Executive Order 11990, “Protection of Wetlands,” DOT Order 5660.1A—Preservation of the Nation’s Wetlands, and Section 404 guidelines mandate that federally funded projects are to avoid construction in wetlands unless (1) there is no practicable alternative and (2) the proposed action includes all practicable measures to minimize harm to wetlands. Practicable means available and capable of being done after taking into consideration cost, existing technology, and logistics, in light of overall project purposes. A practicable alternative is an alternative that is possible (i.e., feasible), after considering safety aspects; ability to meet the action’s transportation objectives; and ability to meet accepted design, engineering, environmental, economic, or any other applicable factors.
There is no practicable alternative to the Proposed Action for the planned airport improvements at EKS. As shown in Chapter 3, other alternatives were considered during the planning process for improvements to EKS, but the Proposed Action was the only alternative that met the stated purpose and need for airport improvements as described in Chapter 2 and was deemed reasonable to implement at EKS. Avoiding wetland impacts along McDeed Creek under the Proposed Action is not practicable because the wider and longer runway and full-length parallel taxiway need to be constructed at specific locations to provide a C-II-5000 facility. McDeed Creek and its associated wetlands run perpendicular to and cross the existing runway and area where the parallel taxiway
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5. ENVIRONMENTAL CONSEQUENCES ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT would be built. For these reasons, encroachments on wetlands along the McDeed Creek are unavoidable. As discussed earlier in this section, the Proposed Action would not significantly impact wetlands at EKS based on a review of the FAA’s identified considerations or thresholds for significant impacts.
An application for a Section 404 permit would be prepared after completion of the NEPA process when detailed plans for the design of airport improvements at EKS have been produced and final impacts to wetland and stream habitat can be accurately determined. Preliminary coordination has been initiated with the COE regarding the need for a Section 404 Permit and compensatory mitigation for wetland and stream impacts associated with the implementation of the Proposed Action. Coordination efforts will continue if this project moves forward. Copies of all correspondence to date with the COE can be found in Appendix A of the EA. Mitigation for Impacts to Wetlands Avoidance and Minimization The only alternatives that avoid impacts to McDeed Creek and its associated fringe wetlands are the No Action Alternative and building a new airport elsewhere in the Madison Valley. These alternatives are not practicable since they do not address the project’s Purpose and Need. Additionally, developing another site for an airport to replace EKS (an alternative dismissed early in the planning process) does not guarantee that impacts to wetlands would not occur at another location. Information about alternatives considered and the reasons why they were eliminated from consideration is found in Chapter 3.
The Proposed Action will be designed and constructed to minimize impacts to wetlands within the project area. The following measures will be included in the project to minimize wetland impacts:
Work in and along McDeed Creek for culvert extensions or installations would be conducted under low or no flow conditions. During construction, appropriate BMPs for preventing sedimentation of adjacent wetlands would be employed. The provisions of FAA Advisory Circular 150/5370-10F, Standards for Specifying Construction of Airports, (September 30, 2011), Item P-156, Temporary Air and Water Pollution, Soil Erosion, and Siltation Control, would be incorporated into the project specifications. Excess embankment material generated during construction of the new runway will not be stockpiled within delineated wetland areas. All necessary permits and agency approvals will be obtained prior to construction, and any permit stipulations will be incorporated into the contract specifications. The limits (boundaries) for vegetation clearing and construction would be delineated by staking, flagging, and fencing to ensure that there is no additional impact from construction activities beyond the work zone. Construction staging areas would be limited to uplands areas to avoid impacts to wetlands.
Compensatory Mitigation Securing a Section 404 permit for the Proposed Action will likely require compensatory mitigation. The Proposed Action would impact an estimated 0.06 acres of PEM wetlands along the fringes of
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McDeed Creek channel to extend and widen the runway and develop an extension to the parallel taxiway. According to the COE, wetland impacts greater than 0.1 acres require mitigation within the same watershed. Impacts to McDeed Creek and Boulder Creek and its tributaries would exceed 300 linear feet due to the need to modify or replace culverts and perpetuate surface drainage. Under the provisions of the Montana Stream Mitigation Procedure (MTSMP), compensatory mitigation is necessary because the impacts to McDeed Creek and Boulder Creek and its tributaries would exceed 0.1 acres and 300 linear feet and require that more than 150 linear feet of streams be placed into new or extended culverts.
Compensatory mitigation involves actions taken to offset unavoidable adverse impacts to wetlands, stream and other aquatic resources authorized by Section 404. Compensatory mitigation is typically achieved through:
restoration of a previously-existing wetland/aquatic site; enhancement of an existing aquatic site’s functions; creation of a new aquatic site; or preservation of an existing aquatic site.
Compensatory mitigation can occur through three options: permittee-responsible compensatory mitigation activity, use of established mitigation banks, and in-lieu fee mitigation. Compensatory mitigation for wetland and stream impacts at EKS would be secured through one or more of these means. Madison County has viable options for mitigating stream and/or wetland impacts within the same watershed including the purchase of mitigation credits from the privately-owned Upper Missouri Mitigation Bank authorized by the COE or the Montana Aquatic Resources Services (MARS), the certified sponsor of the Montana Statewide ILF Program. Impacts to Wild and Scenic Rivers The Ennis Big Sky Airport is not located near any designated or proposed Wild and Scenic River segments in Montana. Therefore, neither the No Action Alternative nor the Proposed Action would affect Wild and Scenic Rivers. Conclusion Implementing the Proposed Action will not result in significant impacts to surface water or surface water quality. This conclusion was reached because the culvert installations necessary associated with the proposed facility improvements will perpetuate surface water flows in McDeed Creek and Boulder Creek and its unnamed tributaries and be sized to adequately handle anticipated flows in the drainages. Measures to manage surface water runoff will also be incorporated into the Proposed Action. Additional safeguards to water quality will be realized by meeting the conditions of necessary water-related construction permits and incorporating BMPs during the construction of the proposed improvements at EKS.
No impacts to groundwater, floodplains, or Wild and Scenic River segments are anticipated.
No significant impact to wetlands is anticipated due to the implementation of the Proposed Action. An estimated 0.06 acres of wetlands and approximately 1,500 linear feet of McDeed Creek would be impacted by the Proposed Action due to the need to construct the proposed northerly runway
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5. ENVIRONMENTAL CONSEQUENCES ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT extension, widen the existing runway, develop a full-length parallel taxiway for the extended runway, and perform earthwork for imaginary airspace surfaces. These impacts are unavoidable and would be mitigated through the provision of compensatory mitigation acceptable to the COE and the Sponsor. 5.16 Cumulative Impacts NEPA requires that potential cumulative effects of past, present, and reasonably foreseeable future actions be evaluated along with the direct and indirect impacts of the actions. According to the CEQ, cumulative impacts represent the:
“…impact on the environment which results from the incremental impact of the action when added to other past, present, and reasonable 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 time.”
A cumulative impact analysis helps determine if the impacts of the proposed airport improvement project would cause a significant impact on environmental resources when added to past, present, and reasonably foreseeable future airport actions and non-airport actions by others. Past actions are actions that occurred in the past and may warrant consideration in determining the environmental impacts of an action. Present actions are any other actions that are occurring in the same general time frame as the proposal. Reasonably foreseeable future actions are actions that may affect the projected impacts of a proposal and are not too far removed from the proposed action or speculative. Cumulative impact analyses typically consider:
the geographic proximity and timeframes of the projects to one another; the probability of actions affecting the same environmental systems or resources; the current condition of potentially affected resources; whether the effects of other projects are similar to those of the project under review; and the likelihood that planned or proposed projects will occur.
This analysis identifies past, present, and reasonably foreseeable future actions that could contribute to cumulative impacts in specific environmental resource categories evaluated earlier in this chapter and highlights project-related effects that could contribute to cumulative impacts in these resource categories. Past, Present, and Reasonably Foreseeable Future Actions In order to help evaluate possible cumulative impacts, past projects at the airport and projects currently underway or planned in the general vicinity of the EKS were identified. Relevant projects or actions are discussed below.
Past Actions As noted in Chapter 4, Madison County’s permanent population has grown at a slow but steady rate over the past two decades. However, seasonal residents and those visiting the area for recreation have affected growth and development patterns in parts of the county—most notably in the Moonlight Basin-Big Sky area situated about 12 air miles east of EKS. Notable past actions or
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5. ENVIRONMENTAL CONSEQUENCES ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT projects occurring at or near EKS since 2013 (the last 5 years) are highlighted in Table 5.8.
Table 5.8: Past Actions
Year Action or Project 2013 Completed preventative pavement maintenance of airside pavements (crack seal, fog seal, and remarking) at EKS. 2014-2015 Rehabilitated the Central Apron, Taxilanes B and C, and a portion of Taxiway A and connecting Taxiway A-3 including fillets, constructed the North Apron, installed guidance signs, and replaced the beacon and both PAPI’s. 2014 Madison County designated an Airport Affected Area (AAA) for EKS and adopted associated AAA regulations. 2015 Acquired Tract 11-B, a vacant 10-acre tract of land adjoining the southwest edge of the Ennis-Big Sky Airport. The property had been listed for sale and the County determined acquisition of the parcel was advantageous for future terminal area improvements at the airport. Conducted Phase I of the 2018 Master Plan Update for the Ennis Big Sky Airport. The airport planning effort was conducted to determine the type of airport facilities that are appropriate for EKS based on current and forecasted aircraft activity. 2015 2016 Acquired Tracts 10-A and 10-B (totaling about 20 acres) which adjoin the southwest perimeter of the airport. The acquisition of these vacant parcels provides land useful for ultimate terminal area expansion. An automated weather recording station (AWOS III/P) was also installed at the airport. 2016 Conducted Phase II of the 2018 Master Plan Update. 2016 The Montana Department of Transportation (MDT) completed its Blaine Spring Cr- 8 M S Ennis project, a bridge replacement over Blaine Spring Creek on the Varney Cutoff Road (Route 249) located about 5.5 miles from the airport. 2017 Acquired a high-speed snow plow truck and installed a present weather sensor on the previously installed AWOS III (converting it to an AWOS III/P). 2017-2018 Madison County acquired portions of land from six parcels adjoining the east side of the airport (Tracts 13-A, 13-B, 20-A, 20-B, 29-A-1, and a 6.44-acre portion of Longhorn Ranches). Efforts to obtain a portion of Tract 4-A were also initiated. The property acquisitions provide additional runway protection for existing Runway 16/34.
Present Actions Table 5.9 lists the present and ongoing actions or projects that were determined relevant for the cumulative impacts analysis.
Table 5.9: Present Actions
Year Action or Project 2018/2019 2018 Master Plan Update - The 2018 Master Plan Update for EKS was completed in June 2018. Based on findings and analyses from the 2018 Master Plan Update, a recommendation was made for improving the airport to meet the FAA’s design standards for the determined critical aircraft (C-II-5000, with >12,500- lbs but <60,000-lbs MTOW). Madison County, in conjunction with the FAA, initiated EA preparation. Construct SRE/AARF Building - An AIP was received in 2018 for the development of a Snow Removal Equipment/Aircraft Rescue and Firefighting (SRE/AARF) building. Construction began in 2019. Land Acquisition - The County continued efforts to acquire Tracts 4-A and began initial efforts to acquire Tract 4-B (1.21-acres) and a perpetual easement on 17.82-acre tract owned by the State of Montana (identified as Tract 6). Routine Maintenance at Airport - Routine maintenance completed by the Owner/Airport Manager – mowing, culvert clearing, weed spraying, etc. Private Hangar Construction - Possible hangar construction by private parties (along Taxilane C). One private hangar is currently under construction, with an unknown completion date. No other formal applications have yet been received; however, several potential parties have expressed preliminary interest.
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Reasonably Foreseeable Future Actions Improvements at EKS would likely be implemented over several years and funded in phases with separate AIP projects. Construction of the Proposed Action is anticipated to begin during 2020 with the majority of the proposed improvements being constructed in 2021 and 2022.
Future projects are listed in the current capital improvement plan (CIP) for EKS for fiscal years 2019-2023 were reviewed to help assess cumulative impacts. The actions listed below in Table 5.10 were identified in the 2018 Master Plan Update for the airport. The five-year CIP is reviewed annually, with a copy of the current approved CIP on file with the FAA in Helena.
Table 5.10: Reasonably Foreseeable Future Actions
Year Action or Project FY 2019 Pilot Lounge - Relocation of the parallel taxiway portion will include demolition of the existing pilot lounge and vault toilet to accommodate the taxiway OFA. A new pilot lounge is proposed for construction near the South Apron; but, the likely timing of its construction is not known at this time.
MDT Project - The MDT proposes to construct its Varney Bridge – 8 M S Ennis project during FY 2019. The project, located on the Varney Cutoff Road (Route 249) about 5.5 miles from airport, would replace the bridge over the Madison River and modify the approaches to the bridge.
Acquire ARFF Equipment - Madison County plans to acquire Aircraft Rescue and Firefighting (ARFF) equipment – it is proposed to acquire government surplus ARFF equipment. It is proposed to acquire a Class 1 or 2 support vehicle, along with a Class 4 vehicle.
Cistern Installation - Madison County plans to install 200,000 to 250,000-gallon pressurized cisterns for water storage and firefighting use. The cisterns’ locations are depicted on the Airport Layout Plan west of the South apron along the west side of the airport access road.
FY 2021 Acquire Snow Removal Equipment (Tractor) - Acquire a snow removal equipment tractor equipped with broom, ramp plow, and rotary plow (snow blower) attachments.
Rehabilitate North Aprons and Taxiways – Perform preventative pavement maintenance on pavements fully reconstructed/constructed in 2016. FY 2022 Acquire Land for Development – Acquire Tracts 22-B and 27-B2, located along the west side of the airport property for "ultimate" Terminal Area development in accordance with the ALP. FY 2023 Construct Hangar Access Taxilane (ADG III) - The airport currently sees itinerant and seasonal ADG III traffic. While the airport is only forecasted to be a C-II airport, accommodating some hangars for ADG III is anticipated to be necessary at this time. Private hangars would be anticipated to store seasonally based aircraft, or function as commercial FBO's.
Expand Aprons - The existing aprons have limited space for future new FBO's or expansion for existing. Additionally, the forecasted growth would result in the need for more apron space, which would be designed to handle large jet traffic.
Extend Hangar Access Taxilane (ADG I) - Extension would allow for an additional six hangars to be constructed along the ADG I Taxilane C. Private hangars construction would be anticipated to occur along the extended taxilane.
Rehabilitate South Apron and Taxiways – Perform preventative pavement maintenance on
pavements anticipated to receive full reconstruction/construction in 2019.
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5. ENVIRONMENTAL CONSEQUENCES ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT
For the past three decades, the Big Sky area has been a growth center in Madison County for both jobs and housing. Based on the County-approved master plans for major developments in the Big Sky area (Boyne USA, Moonlight Basin Ranch, Spanish Peaks Resort, and Yellowstone Club), continued residential, commercial, and recreational development is expected. Recent development plans for the Moonlight Basin Ranch and Big Sky Resort support this assertion. The August 2017 Moonlight Basin Overall Development Plan states that of the 1,651 allocated housing units that were previously approved in 2007, more than 450 have already been subdivided and/or developed and nearly 1,200 remain to be developed. The 2017 Overall Development Plan proposes approval of an additional 190 housing units on the property and provide facilities catering to year-round recreation. During August 2016, Boyne Resorts released Big Sky 2025: A Focused Vision for the Future, a 10-year improvement plan for the ski area. The plan outlines $150 million in proposed improvements to increase recreational facilities, services, and other amenities on the mountain.
Note that any potential development or construction activities at EKS which will result in a change to the ALP requiring FAA approval will also require an analysis in accordance with NEPA. Such projects, regardless of whether federally-funded or not, constitute a federal action and must be accomplished in accordance with the NEPA process prior to their implementation. Environmental Impact Categories The following subsections analyze the potential cumulative impacts for each of the environmental resource categories in which the implementation of the Proposed Action might contribute to cumulative impacts. For some resource categories, implementation of these alternatives would have no impact and would not, therefore contribute to cumulative impacts.
The analyses earlier in this chapter determined the implementation of the Proposed Action would generate impacts in the categories below which, though not significant in themselves, must be analyzed for their possible cumulative effect. The following sections discuss the potential cumulative impacts for each environmental resource category in which the Proposed Action might contribute to cumulative impacts when considered with other past, present, and reasonably foreseeable actions.
Air Quality A significant impact to air quality could occur if the project alternatives, when considered in combination with other past, present, or reasonably foreseeable actions, would result in one or more NAAQS for criteria pollutants being exceeded or adversely affect the attainment status of the Madison Valley area.
Aircraft using EKS, airport maintenance and support activities, and ground vehicles traveling to and from the airport emit air pollutants. The amount of such emissions would incrementally increase with or without airport improvements as aviation forecasts for EKS predict more aviation activity in the future. However, as the results of the air quality analysis presented in Section 5.2 of this chapter shows, increased future aviation operations and implementation of the proposed improvements would not cause any exceedances of the NAAQS or MAAQS. Past, present and future development, both at EKS and elsewhere in the Madison Valley, has and will likely continue to contribute to minor localized increased emissions of air pollutants. However, when added to other
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5. ENVIRONMENTAL CONSEQUENCES ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT emissions sources in the area, the incremental increase in emissions from the proposed airport improvements and its future use are minor and no significant cumulative impact on air quality is anticipated.
Activities associated with the implementation of the Proposed Action would produce dust and vehicle emissions during construction phases. Other planned projects may also generate similar air pollutants as they are built. The cumulative effects on air quality would depend on the timing of activities, duration of construction activities, and the proximity of the other project areas to EKS. The only known reasonably foreseeable action or project by others near the airport during the anticipated construction phases at the airport is a bridge replacement project located 5.5 miles from the airport on Varney Road. It is unlikely that project would contribute to cumulative impacts to air quality during the construction phases at the airport.
Coastal Resources There is no potential for cumulative impacts due to the implementation of the Proposed Action because there are no coastal resources in the State of Montana.
Land Use The Proposed Action, when considered with other past, ongoing, and reasonably foreseeable future projects, would result in minimal changes to land use in the vicinity of EKS. Since 2015, Madison County has been proactive and purchased three 10-acre residential tracts along the west side of the airport that were offered for sale. These tracts help provide land needed for future terminal area development at the airport. The County has also acquired Tracts 13-A, 13-B, 20-A, 29-A-1, and a parcel from the Longhorn Ranch parcel—all located along the eastern edge of the Airport. These parcels currently provide runway protection but are sufficient in size to accommodate the OFA and other changes necessary to meet design standards for a C-II-5000, with MTOW greater than 12,500- lbs but less than 60,000-lbs, facility,
The acquisition of new land from properties adjoining the airport (Tracts 4-A, 4-B, and Tract 6) would be necessary to implement the Proposed Action. Except for large agricultural tracts at the north end of the existing runway, lands surrounding the airport consist primarily of large (6-10 acre) rural residential subdivision tracts which have seen little development. The acquired property would be converted from generally vacant rural residential subdivision land and grazing land to publicly-owned land used for airport purposes.
No residences or other noise-sensitive land uses are located within the DNL 65 dB noise exposure contours for the Proposed Action. Madison County has implemented AAA regulations to help ensure compatible land uses occur adjacent to and in the general vicinity of the airport. This action would help avoid adverse cumulative impacts with respect to compatible land use.
Department of Transportation Act: Section 4(f) The Proposed Action when considered with other ongoing and reasonably foreseeable future actions would not result in impacts to Section 4(f) properties at or near EKS. There are no federal, state or local parks, recreation areas, or wildlife refuges of national, state, or local significance adjacent to the airport.
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5. ENVIRONMENTAL CONSEQUENCES ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT
Only one historic property— the NRHP-eligible Granger Ditch (24MA2400)—qualifies as a Section 4(f) property in the general project area. Although a section of the historic irrigation ditch crosses the western portion of the airport property, no activities or facility modifications associated with the Proposed Action would occur in or near the historic irrigation ditch. On April 2, 2018, the Montana SHPO concurred with the FAA’s determination that there would be no adverse effect on historic properties located within the Area of Potential Effect for the proposed improvement project at EKS.
The No Adverse Effect determination for historic properties also means there would be no use of historic properties qualifying for consideration under Section 4(f). None of the other ongoing or reasonably foreseeable future projects considered in this analysis would affect the Granger Ditch which crosses the airport property. Therefore, no cumulative Section 4(f) impacts are expected.
Farmlands As discussed in Section 5.5, a significant farmland impact for federal projects is determined based on the site assessment score shown on NRCS Form AD-1006. Total site assessment scores ranging from 200 to 260 are indicative of potentially significant farmland impacts. The analysis of farmland impacts for this proposed project resulted in a total site assessment score of 86 for the Proposed Action. This score is substantially below the threshold identified for significant farmland impacts.
Scattered rural residential development around the Ennis Big Sky airport and elsewhere in the Madison Valley has resulted in the incremental conversion of farmland to non-agricultural uses. This trend is likely to continue in the future given the attractiveness of the area for tourism and recreation which drives seasonal housing development in Madison County. The rate and timing of farmland conversions is difficult to predict and depends on the timing and extent of new recreational development at major resort areas and associated demands for housing. It is also possible that some agricultural uses may be able to continue in the future on newly acquired lands for the airport. For these reasons, the Proposed Action would not be expected to have a significant adverse cumulative impact on farmlands.
Biological Resources (Including Fish, Wildlife, and Plants) The Proposed Action when considered with past, present, and reasonably foreseeable future actions and project would cause additional minor impacts to fish, wildlife and plants in the airport area. The implementation of airport improvements at EKS may result in the displacement of some small wildlife species or birds and could result in a minor permanent loss of habitat for some species. Similar impacts have occurred throughout the broader Madison Valley for several decades as rural residential and resort developments have encroached on rural lands in Madison County. Although wildlife species use the area around EKS, available habitat is not of high quality due to past disturbances associated with agriculture, residential development, and airport operations. No critical habitat has been designated on lands in the immediate project area and no federally-listed species or Montana species of concern are known to occur on the airport or its immediately adjoining lands.
With these considerations in mind, implementing the Proposed Action would not result in significant cumulative impacts on fish, wildlife, and plants in the project area.
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5. ENVIRONMENTAL CONSEQUENCES ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT
Hazardous Materials, Solid Waste, and Pollution Prevention A significant cumulative impact related to hazardous materials could occur if the Proposed Action, when considered in combination with other past, present, or reasonably foreseeable actions, would:
Involve a property on or eligible for the NPL; Result in difficulties for the sponsor in meeting applicable laws and regulations regarding hazardous materials; or Involve a notable unresolved issue regarding hazardous materials.
The proposed airport improvements do not involve any property on or eligible for the NPL. Similarly, the past, present, and reasonably foreseeable future actions listed earlier in this section do not and would not involve known or potential NPL sites.
The airport improvements when considered with these other identified projects would not significantly increase the amount of hazardous materials and solid waste handled within the project area. Runway construction requires oil and other components to produce asphalt pavement and the operation of construction equipment increases the potential for leaks of petroleum products. Fuel storage, spill prevention, and emergency response measures in place at EKS will enable the County and FBO at the airport to continue meeting applicable local, state, or federal laws and regulations regarding hazardous materials.
No fuel spills or storage tank leaks have occurred in the past on the airport and there are no unresolved hazardous materials issues at the airport. No hazardous materials issues are apparent at the locations of other reasonably foreseeable future actions in the area.
The amount of demolition debris requiring disposal in the local landfill when considered with other reasonably foreseeable project would not be expected to substantially affect the capacity or lifespan of the Ennis landfill. Old asphalt paving material does not require disposal and could be stockpiled at the airport or recycled for future use.
For these reasons, no significant adverse cumulative impact related to hazardous materials or solid waste would occur if airport improvements are implemented together with other past, present, or reasonably foreseeable actions.
Historical, Architectural, Archeological, and Cultural Resources The Proposed Action when considered with other ongoing and reasonably foreseeable future actions do not result in impacts to historical or cultural resources in the vicinity of EKS.
As noted earlier in this section, the Granger Ditch (24MA2400) is the only historic property near the project area. Although a section of the Granger Ditch crosses the western portion of the airport property, no activities or facility modifications associated with the Proposed Action would occur in or near the historic irrigation ditch. Construction-related activities would not cause any temporary impacts to the historic irrigation ditch.
On April 2, 2018, the Montana SHPO concurred with the FAA’s determination there would be no adverse effect on historic properties located within the Area of Potential Effect for the proposed improvement project at EKS. Since none of the other ongoing or reasonably foreseeable future
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5. ENVIRONMENTAL CONSEQUENCES ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT projects considered in this analysis would affect the Granger Ditch, no cumulative impacts to historical properties are anticipated.
Visual Effects (Including Light Emissions) The Proposed Action when considered with other past, present, and reasonably foreseeable future actions would cause minor visual changes within the project area. The most notable visual change would be associated with the earthwork and grading necessary to extend and widen Runway 16/34 and provide a full-length parallel taxiway. Extending and widening the runway requires substantial excavation and grading north and east of the present runway. This area would be readily visible for residents of some adjoining lands. Additional visual changes would include the expansion of the MIRL system, the relocation of several NAVAIDS, and lighting along the full-length parallel taxiway. These changes would not be out of character with the long-term use of this site as an airport.
Due to these visual changes, new airfield lighting may be visible to some additional area residents. However, the intensity of these lights to nearby residents should not be substantially increased over current conditions. Revegetation of disturbed areas would help minimize visual changes associated with construction of airport improvements.
Due to the distance between EKS and the work areas for other projects, no significant adverse cumulative impacts are anticipated with respect to light emissions and the visual environment.
Natural Resources and Energy Supply The Proposed Action when considered with other ongoing and reasonably foreseeable actions would result in minimal cumulative impacts to natural resources or energy supplies. The community of Ennis and the broader Madison Valley area have adequate supplies of natural resources and energy for the airport project and other identified foreseeable projects.
Climate The cumulative impact of the Proposed Action on the global climate when added to other past, present, and reasonably foreseeable future actions is not currently scientifically predictable.
Aviation has been calculated to contribute approximately 3 percent of global CO2 emissions; this contribution may grow to 5 percent by 2050. Actions are underway in the U.S. and by other nations to reduce aviation’s contribution through such measures as new aircraft technologies to reduce emissions and improve fuel efficiency, renewable alternative fuels with lower carbon footprints, more efficient air traffic management, market-based measures and environmental regulations including an aircraft CO2 standard.
The U.S. has ambitious goals to achieve carbon-neutral growth for aviation by 2020 compared to a 2005 baseline, and to gain absolute reductions in GHG emissions by 2050. At present there are no calculations of the extent to which measures individually or cumulatively may affect aviation’s CO2 emissions. Moreover, there are large uncertainties regarding aviation’s impact on climate. The FAA, with support from the U.S. Global Change Research Program and its participating federal agencies (e.g. NASA, NOAA, EPA, and DOE), has developed the Aviation Climate Change Research Initiative (ACCRI) in an effort to advance scientific understanding of regional and global climate
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5. ENVIRONMENTAL CONSEQUENCES ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT impacts of aircraft emissions, with quantified uncertainties for current and projected aviation scenarios under changing atmospheric conditions.4
Noise and Compatible Land Use As shown earlier in this chapter (see Figure 5‐2), the DNL 65 dB noise exposure for the existing airport generally falls over airport lands and other undeveloped lands near the airport. Due to the northerly extension of Runway 16/34, the Proposed Action shift the DNL 65 dB contour northward and the widest part of the contour would remain over grazing land. There are no noise-sensitive land uses immediately adjoining the airport that would experience a project-related increase in noise at levels that suggest the likelihood of a significant cumulative noise impact.
The DNL 65 dB (and higher) noise exposure contours associated with the Proposed Action is based on incremental increases in forecasted in aviation activity EKS and they generally encompass existing airport property, vacant lands in the Shining Mountains Airport Subdivision, and undeveloped grazing lands to the north and east of the airport. Past, ongoing, and reasonably foreseeable future actions by other parties in the vicinity of EKS have little, if any, potential to affect aircraft noise levels or traffic patterns at the airport. For this reason, there is no potential for the implementation of the Proposed Action to contribute to a significant cumulative noise impact.
The Proposed Action would not alter surface traffic patterns or traffic volumes on the roadways leading to EKS and would therefore, not contribute to cumulative increases in vehicular traffic noise in the area.
Socioeconomics, Environmental Justice, and Children’s Environmental Health and Safety Risks The Proposed Action when considered with other ongoing and reasonably foreseeable future actions do not result in impacts to environmental justice populations or increase children’s health and safety risks.
The Proposed Action would remove 3.17 acres from the property tax base of the County. This loss in tax revenue would be minor since the private land needed for airport development consists of undeveloped areas within larger (typically 6.4 acres in size) rural residential parcels. Future investments in private hangars or leasable hangar space at the airport could help offset the loss of property tax revenue by generating new revenue for Madison County. The provisions of the Uniform Act would be followed to ensure fair and consistent acquisition of real property for affected landowners.
For these reasons, no cumulative adverse socioeconomic impacts are anticipated.
Water Resources A significant cumulative impact on water quality could occur if the Proposed Action, when considered in combination with other past, ongoing, or reasonably foreseeable actions, would
4 Nathan Brown, et. al. The U.S. Strategy for Tackling Aviation Climate Impacts, (2010). 27th International Congress of the Aeronautical Sciences.
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5. ENVIRONMENTAL CONSEQUENCES ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT exceed water quality standards, cause water quality problems that could not be avoided or satisfactorily mitigated, or result in difficulty in obtaining a permit or authorization. A significant cumulative impact on wetlands could occur if the Proposed Action, when considered in combination with other past, ongoing, or reasonably foreseeable actions, adversely affected the key functions and values provided by delineated wetlands.
The potential impacts to water quality in the area would be greatest if the airport improvements were built concurrently with other reasonably foreseeable projects and involved substantial ground disturbances or work in McDeed Creek and other drainages passing through the airport.
The proposed improvements at EKS require work within McDeed Creek, Boulder Creek and two unnamed tributaries to Boulder Creek. These streams have been impacted by past development of the Shining Mountains Airport Subdivision and previous improvements at EKS; However, none of the other past or reasonably foreseeable projects at or near EKS affect these streams.
As noted in Section 5.16 of this chapter, the primary potential for impacts to water quality associated with the alternative would occur during construction as land is disturbed to extend and widen the new runway, provide a full-length parallel taxiway, complete imaginary surface airspace grading, and expand apron and hangar areas. The potential exists for erosion of disturbed areas and sediment transport to surface waters through stormwater runoff.
Measures to prevent water quality impacts associated with erosion and sediment transport would be required and enforced through the MDEQ’s General Permit for Storm Water Discharges Associated with Construction Activity. Compliance with the requirements of this permit would preclude the construction impacts of the Proposed Action from contributing to potentially significant cumulative impacts to water quality in the area. Work within the bed and banks of McDeed Creek and Boulder Creek and its tributaries would also be subject to permit approval from the COE, MFWP, and MDEQ which would help safeguard surface water quality.
As noted earlier in this chapter, the only wetlands affected by the proposed improvements are McDeed Creek and its associated fringe area. None of the reasonably foreseeable projects identified in Table 5.10 have the potential to result in additional impacts to McDeed Creek wetlands.
The analysis documented in this chapter showed the construction of the Proposed Action would result in the permanent loss of approximately 0.06 acres of wetlands along approximately 1,500 linear feet of McDeed Creek. Impacts to delineated wetlands would be mitigated as described earlier to address potential losses of functions and values. Mitigation would comply with the COE’s established mitigation ratios for wetland losses and the agency’s MTSMP. Mitigation for impacts would be provided within the same watershed as EKS, at the Upper Missouri Mitigation Bank or an approved project associated with the Montana Statewide In-Lieu Fee Mitigation Program.
With acceptable mitigation in place, no cumulative impacts to wetlands are anticipated. Conclusion Based on the previous analysis, no significant cumulative impacts to the environment are anticipated due to the implementation of the Proposed Action considering the past, present, and reasonably foreseeable future actions in in the EKS area.
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ENVIRONMENTAL ASSESSMENT ENNIS BIG SKY AIRPORT MADISON COUNTY, MT
SUMMARY OF PUBLIC INVOLVEMENT
ROBERT PECCIA & ASSOCIATES
SUMMARY OF PUBLIC INVOLVEMENT ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT
SUMMARY OF PUBLIC INVOLVEMENT
Public Involvement for the Master Plan Update FAA Advisory Circular 150/5070-6B Change 2 (1/27/2015) provides guidance for the preparation of master plans for airports. The AC stresses the need for including public involvement activities proportional to the complexity of the planning study and to the degree of public interest.
During the development of the 2018 Master Plan Update, three public open house meetings were held to convey information about the proposed airport improvements at EKS and to solicit comments and input. Each public meeting was duly advertised to the public in advance of the meetings. Despite advance meeting notices, attendance by the public at the Master Plan Update meetings was low.
The open house meetings, held at key stages of the planning process, are briefly summarized below.
April 11, 2016 Meeting. An open house informational meeting was held on April 11, 2016 to discuss the aviation forecasts for EKS. The meeting occurred at the Choice Aviation building at EKS and began at 5:30 p.m. The purposes of the meeting were to provide an overview of the Airport Master Plan process, summarize existing aviation facilities at the airport, and present the operational baseline and activity forecasts for EKS. Factors influencing aviation forecasts, the forecasted change in critical aircraft category at the airport from B-II to C-II, and activity forecasts for itinerant, local, air taxi, and military operations were presented.
April 10, 2017 Meeting. An open house informational meeting was held on April 10, 2017 at the Choice Aviation building at EKS and began at 5:30 p.m. The purposes of the meeting were to discuss changes to the type of airport facilities that are appropriate for EKS based on current and forecast aircraft activity and the identified critical aircraft category. Most notably, the meeting highlighted the type of design changes needed for a C-II facility. The meeting also included discussion about the primary and secondary planning considerations influencing the development of alternatives. Four broad categories of alternatives were presented to address aviation needs including: Alternative #1-Do Nothing; Alternative #2- Build an Airport at an Alternate Site; Alternative #3-Improve the Facility with a Shifted Runway Threshold; and Alternative #4-Extending the Runway to the North.
In conjunction with the April 2017 meeting, a newspaper article about the 2018 Master Plan Update for EKS and its key findings was published in the Madisonian on April 19, 2017. A copy of the article can be found in this Appendix.
November 2, 2017 Meeting. A third open house informational meeting was held on November 2, 2017 at the Choice Aviation building at EKS and began at 5:30 p.m. The meeting was used to present a Draft ALP set for EKS illustrating recommended “future” and “ultimate” facility development concepts for the airport. The Draft ALP depicts changes necessary to transform the airport from a B-II to C-II facility over a 20-year period.
PI-1
SUMMARY OF PUBLIC INVOLVEMENT ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT
The 2018 Master Plan Update process and its associated public meetings provided data and input used to develop this Environmental Assessment. The results of the 2018 Master Plan Update effort helped refine the purpose and need and identify reasonable alternatives for improvements at EKS. The public meetings provided an opportunity for members of the Madison County Board of Commissioners, the Airport Board, and general public to discuss recommended facility modifications and a variety of considerations that may affect future development projects at the airport.
Sign-in sheets, presentation materials, and summaries of public comments heard at the meetings can be found in Appendix, H, Appendix M, and Appendix N of the 2018 Master Plan Update (Appendix E in this EA). Public Availability of the Draft EA Madison County has actively sought involvement from federal, state, and local agencies as well the general public in preparing this EA. This coordination will be completed after the public availability period for the Draft EA concludes. Comments received during the public availability period for the Draft EA will be addressed as required in the Final EA.
The Draft EA was made available for public review online and as a printed document for a period of 45 days beginning on August 14, 2019 and ending on September 27, 2019. A Notice of Public Hearing and Availability of the Draft EA for the Ennis Big Sky Airport Improvements was published in the Madisonian on August 15, 2019 and September 12, 2019. An Affidavit verifying the publication of the Notice is provided on page PI-3.
Printed copies of the Draft EA were made available for public review at the following locations during regular business hours:
Madison County Commissioner’s Office Ennis Big Sky Airport 103 W Wallace St Choice Aviation Virginia City, MT, 59755 35 Runway Road Ennis, MT 59729 Madison Valley Public Library 210 E Main Ennis MT 59729
The Draft EA was also available for review in electronic form on the following website:
http://www.rpa-hln.com/ennis-airport-draft-ea.html
Additionally, a link for viewing the Draft EA was provided on the “Public/Legal Notices” webpage of Madison County’s website.
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SUMMARY OF PUBLIC INVOLVEMENT ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT Public Hearing Notice
As previously discussed, a Notice announcing the availability of the Draft EA and a scheduled Public Hearing on the Draft EA was published in the Madisonian on August 14, 2019 and September 11, 2019. The Notice provided the date, time, and location for the Public Hearing and indicated the hearing would provide information about the Proposed Action and its associated environmental impacts and offer an opportunity to submit comments.
Paragraph 2-5.3b of FAA Order 1050.1F requires the FAA to make Draft EAs available for public review for at least 30 days before a public hearing is held. The Draft EA was made available for public review on August 14, 2019—35 days prior to the Public Hearing.
The date, time, location and meeting details for the Public Hearing on the Draft EA was also listed on the “Public/Legal Notices” webpage of Madison County’s website. Public Hearing on the Draft EA
Madison County held a public hearing on the Draft EA on Tuesday, September 17, 2019 at 5:30 p.m. at the Madison County Public Meeting Room, Madison County Administrative Offices Building, 103 West Wallace, Virginia City, Montana. The Public Hearing provided information to present information about the analyses and findings in Draft EA, the Proposed Action identified in the Draft EA, and to receive oral and written comments on the Draft EA.
Lynda Brown served as the Public Hearing Officer and presided over the hearing. Two representatives from the FAA’s Helena Airports District Office—Joe Nye and Diane Stilson—were present. Additionally, Lance Bowser and Dan Norderud of Robert Peccia & Associates attended and participated in the hearing. Dan Norderud provided an overview of the Draft EA prior to the meeting being opened for public comments. A copy of the presentation slides is
In addition to those mentioned above, ten (10) people including all three Madison County Commissioners and other County staff and members of the Airport Board signed the attendance sheets for the Public Hearing. Copies of the sign-in sheets are provided on pages PI-5 and PI-6. None of those present offered oral comments or provided written comments at the Hearing.
The Public Hearing was transcribed in its entirety by Kim Marchwick of Red Rhino Reporting located in Bozeman, Montana. A copy of the transcript begins on page PI-7 followed by copies of presentation slides from the hearing. Written Comments Received on the Draft EA
Written comments regarding the Draft EA were solicited during the public review period as follows:
• Hand-delivered at the September 17, 2019 Public Hearing. • By mail to Dan Norderud at Robert Peccia & Associates, P.O. Box 5653, Helena, MT 59604 if post marked by September 27, 2019. • By email to [email protected] by 5:00 p.m. MDT on September 27, 2019.
No written comments were received at during the public review period for the Draft EA.
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ENVIRONMENTAL ASSESSMENT ENNIS BIG SKY AIRPORT MADISON COUNTY, MT
LIST OF PREPARERS
ROBERT PECCIA & ASSOCIATES
LIST OF PREPARERS ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT
LIST OF PREPARERS
Robert Peccia & Associates, Inc., Consulting Engineers, based in Helena, Montana was responsible for providing the transportation, civil and environmental engineering analysis contained in this document. Staff from the Federal Aviation Administration offered technical expertise and policy guidance during the preparation of the EA. Additionally, the Madison County Board of Commissioners and Madison County Airport Board provided local expertise and comments for this airport development action.
ROBERT PECCIA & ASSOCIATES, INC. The personnel directly responsible for preparing this Environmental Assessment are as follows:
• Lance Bowser, P.E., Montana #16502PE, Project Manager 14 years of professional experience
• Daniel M. Norderud, AICP, Certificate #013117, Environmental Planner 39 years of professional experience
• Nancy Geary, Engineering Designer – GIS/Graphics 21 years of professional experience
SUBCONSULTANTS The firms and personnel listed below provided specialized expertise and prepared supporting studies and resource reports for this Environmental Assessment:
METCALF ARCHAEOLOGICAL CONSULTANTS, INC. - Cultural Resources Inventory Bozeman, Montana
• Jennifer Borresen Lee, M.A. - Regional Manager - 14 years of professional experience • Craig M. Lee, Ph.D., RPA - Research Director and Principal Investigator - 17 years of professional experience
RESPEC, INC. – Biological Resources and Aquatic Resources Report Helena and Missoula, Montana
• Mark Traxler, Biology/Wetlands - 26 years of professional experience • Kevin S. Schroeder, PWS, Biology - 27 years of professional experience
BRIDGENET INTERNATIONAL – AEDT Air and Noise Emissions Modeling Newport Beach, California
• Paul H. Dunholter, P.E., Noise Contours – 40 years of professional experience • Mary Vigilante – Air Quality Assessment – 40 years of professional experience
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LIST OF PREPARERS ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT
U.S. DEPARTMENT OF TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION Helena Airports District Office (Helena, MT)
• William Garrison, Manager • Scott Eaton, Airport Planner (MT, ID) • Joe Nye, Airport Engineer (MT) • Diane Stilson, P.E. Environmental Protection Specialist/Airport Engineer Northwest Mountain Region Airports Division (Renton, WA)
• Janell Barrilleaux, Environmental Program Manager
MADISON COUNTY BOARD OF COMMISSIONERS
• Dan Allhands, District 1 • Ron Nye, District 2 - Chairman • Jim Hart, District 3
MADISON COUNTY AIRPORT BOARD
• Ernest Bock • Beau Bradley • Peter Fitzgerald • James C. Frey • John Hauck • Tom Miller (Chairman) • Scott Payne
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LIST OF AGENCIES AND PERSONS CONSULTED
ROBERT PECCIA & ASSOCIATES
LIST OF AGENCIES AND PERSONS CONSULTED ENNIS BIG SKY AIRPORT ENVIRONMENTAL ASSESSMENT
LIST OF AGENCIES AND PERSONS CONSULTED
FEDERAL AGENCIES CONTACTED
U.S. Army Corps of Engineers Dale Olson, District Ranger Helena Regulatory Office Beaverhead-Deerlodge National Forest 10 West 15th Street, Suite 2200 Madison Ranger District Helena, MT 59626-9705 5 Forest Service Road Ennis, MT 59729
STATE AGENCIES CONTACTED
David Moser, Fisheries Biologist John Kenning, Bureau Chief Montana Department of Fish, Wildlife, and Montana Department of Environmental Parks Quality Region 3 Water Protection Bureau 1400 South 19th 1520 East Sixth Avenue Bozeman, MT 59718 P.O. Box 200901 Helena, MT 59620-0901 Julie Cunningham, Area Biologist Montana Department of Fish, Wildlife, and David Klemp, Bureau Chief Parks Montana Department of Environmental Region 3 Quality 1400 South 19th Air Quality Bureau Bozeman, MT 59718 P.O. Box 200901 Helena, MT 59620-0901
Department of Natural Resources and Conservation Central Land Office 8001 N. Montana Avenue Helena, MT 59602-9388
LOCAL AGENCIES AND OTHERS CONTACTED
Charity Fechter, Planning Director Ennis Area Chamber of Commerce Madison County Planning Office PO Box 291 PO Box 278 Ennis, MT 59729 Virginia City, MT 59755 Town of Ennis Jani Flinn, Airport Board Secretary Attn: Mayor Larry Pine Madison County P.O. Box 147 PO Box 278 Ennis, Montana 59729 Virginia City, MT 59755 Matt Bell, Land Steward Montana Land Reliance 324 Fuller Ave PO Box 355 Helena, MT 59624-0355
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