Red Rock/Lima Watershed Environmental Analysis
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RED ROCK/LIMA WATERSHED ENVIRONMENTAL ANALYSIS Environmental Assessment DOI-BLM-MT-B050-2018-0009-EA 5/22/2018 U.S. Department of the Interior Bureau of Land Management Dillon Field Office 1005 Selway Drive Dillon, Montana 59725 Phone: (406) 683-8000 Fax: (406) 683-8066 TABLE OF CONTENTS Chapter 1 Purpose and Need for the Proposed Action ................................................................... 1 Introduction & Background ........................................................................................................ 1 Purpose and Need ....................................................................................................................... 3 Decision to be Made ................................................................................................................... 7 Conformance with Land Use Plan .............................................................................................. 8 Relationship to Statutes, Regulations, other Plans, or other NEPA Documents ........................ 8 Public Involvement ..................................................................................................................... 9 Resource Issues Identified for Analysis .................................................................................... 10 Resource Issue #1: Riparian, Wetland and Aquatic Habitat ..................................................... 10 Resource Issue #2: Upland -Sagebrush and Grassland Habitat ................................................ 11 Resource Issue #3: Forest and Woodland Habitat .................................................................... 12 Resource Concern #1: Special Status Species and Big Game Habitat ..................................... 12 Resource Concern #2: Socioeconomics .................................................................................... 13 Resource Concern #3: Noxious and Invasive Species .............................................................. 13 Resource Concern #4: Travel Management .............................................................................. 14 Resource Concern #5: Visual Resource Management .............................................................. 14 Resource Concern #6: Wilderness Study Areas ....................................................................... 15 Resource Concern #7: Cultural and Paleontological Resources ............................................... 16 Issues/Resources Considered but Eliminated from Further Analysis ....................................... 16 Chapter 2 Proposed Alternatives .................................................................................................. 18 Introduction ............................................................................................................................... 18 Process Used to Formulate Alternatives ................................................................................... 18 Alternatives Considered but Eliminated ................................................................................... 18 Alternatives Considered but Eliminated from Detailed Analysis ............................................. 18 Features Common to All Alternatives ...................................................................................... 20 Alternative A (No Action) ........................................................................................................ 25 Features Common to All Action Alternatives .......................................................................... 34 Alternative B ............................................................................................................................. 52 Alternative C ............................................................................................................................. 68 Alternative D ............................................................................................................................. 71 Comparison of Alternatives ...................................................................................................... 72 Chapter 3 AFFECTED ENVIRONMENT ................................................................................... 79 Introduction ............................................................................................................................... 79 General Setting.......................................................................................................................... 79 Relevant Past and Ongoing Actions: ........................................................................................ 80 Resources Brought Forward for Analysis ................................................................................. 82 Chapter 4 Environmental Effects ................................................................................................ 108 Introduction ............................................................................................................................. 108 Resource Issue #1: Riparian, Wetland and Aquatic Habitat Environmental Effects .............. 108 Resource Issue #2: Upland Sagebrush and Grassland Habitat Environmental Effects .......... 133 Resource Issue #3: Forest and Woodland Habitat Environmental Effects ............................. 144 Resource Concern #1: Special Status Species and Big Game Habitat Environmental Effects ................................................................................................................................................. 150 Resource Concern #2: Socioeconomics Environmental Effects ............................................. 168 Resource Concern #3: Noxious and Invasive Species Environmental Effects ....................... 174 Resource Concern #4: Travel Management Environmental Effects ....................................... 175 Resource Concern #5: Visual Resource Management Environmental Effects ....................... 179 Resource Concern #6: Wilderness Study Areas Environmental Effects ................................ 181 Resource Concern #7: Cultural and Paleontological Resources Environmental Effects ........ 183 Chapter 5 Consultation and Coordination................................................................................... 186 Introduction ............................................................................................................................. 186 Persons, Groups, and Agencies Consulted ............................................................................. 186 List of Preparers ...................................................................................................................... 187 Glossary .................................................................................................................................. 188 References ............................................................................................................................... 190 Chapter 6 Appendices ................................................................................................................. 204 Chapter 1 Purpose and Need for the Proposed Action Introduction & Background The Red Rock/Lima Watershed (RRLW) is located in southern Beaverhead County, Montana. The watershed lies in Townships 8-16 South, Ranges 6-12 West, Montana Principal Meridian (M.P.M). The RRLW follows the I-15 corridor from the Barrett’s exit south of Dillon, Montana south to the Montana/Idaho border near Monida, Montana. This assessment covers only BLM administered public lands in this area. The RRLW is primarily in the central portion of the 4th level Hydrologic Unit (HU) known as the Red Rock (10020001) used by the Montana Department of Environmental Quality (DEQ). The RRLW also overlaps a small portion of the Beaverhead HU (ID# 10020002). The current watershed boundary for the RRLW has been modified from the boundary area used during the 2007 watershed assessment process. Some areas have been removed, while other areas that were assessed as part of the Beaverhead West Watershed in 2007 were included into the RRLW. Additionally, during the Sage Creek Watershed planning process (2015-2016), a small portion of BLM land was administratively moved into the Red Rock Watershed from the Sage Creek Watershed, while some of the Red Rock Lima watershed was moved to the Sage Creek Watershed. The watershed boundary modification was an administrative remedy to improve efficiency of workloads and rangeland administration throughout the entire Dillon Field Office. Watershed Boundaries continue to follow grazing allotment boundaries, not the HU watershed boundaries. The RRLW assessment area within the Dillon Field Office boundary is shown on the vicinity map below as well as Map 1 in appendix A. 1 Within the RRLW there are approximately 338,027 acres. Of these acres, 69,730 acres are BLM managed public land. This represents approximately 21 percent of the watershed. This Environmental Assessment (EA) addresses only the public lands administered by the BLM. There are also 80,948 acres (24% of the watershed) administered by the United States Forest Service (USFS), 9,500 acres (3% of the watershed) administered by the Bureau of Reclamation (BOR), 53,451 acres (16% of the watershed) administered by the Montana Department of Natural Resources and Conservation (DNRC), and 124,394 acres (37% of the watershed) of privately owned lands within the RRLW. Elevations on BLM administered public land within the RRLW