United States Department of the Interior Bureau of Land Management Environmental Assessment Twin Falls District Noxious Weed and Invasive Plant Treatment DOI-BLM-ID-T000-2012-0001-EA U.S. Department of the Interior Bureau of Land Management Twin Falls District 2878 Addison Avenue East Twin Falls, ID 83301 Phone: (208) 735-2060 FAX: (208) 735-2076 Table of Contents CHAPTER 1 - PURPOSE AND NEED FOR ACTION .............................................................. 13 Background ............................................................................................................................... 13 Introduction ............................................................................................................................... 14 Location of Proposed Action ................................................................................................ 15 Purpose and Need for Action .................................................................................................... 19 Conformance with Applicable Land Use Plans ........................................................................ 19 FMDA ................................................................................................................................... 20 Jarbidge RMP........................................................................................................................ 20 Craters of the Moon Monument MP ..................................................................................... 21 Owyhee Canyonlands Wilderness MP.................................................................................. 22 Idaho and Southwestern Montana and Nevada and Northeastern California Greater Sage- Grouse Approved Resource Management Plan Amendments (ARMPA)/Final EISs .......... 22 Relationship to Statutes, Regulations or Other Plans ............................................................... 22 Tiering and Incorporation by Reference ................................................................................... 25 Scoping, Public Involvement, and Issues ................................................................................. 26 CHAPTER 2 - PROPOSED ACTION AND ALTERNATIVES ................................................. 32 Proposed Action ........................................................................................................................ 32 Targeted Plant Communities..................................................................................................... 32 Noxious Weeds ..................................................................................................................... 32 Invasive Plants ...................................................................................................................... 33 Treatment Planning ................................................................................................................... 34 Integrating Vegetation Treatments ....................................................................................... 35 General Site Selection and Treatment................................................................................... 35 Cooperative Weed Management Areas and Partnerships ..................................................... 37 Prevention ............................................................................................................................. 37 Treatment Methods ................................................................................................................... 37 Manual Methods ................................................................................................................... 38 Mechanical Methods ............................................................................................................. 39 Prescribed Fire ...................................................................................................................... 41 Biological Control ................................................................................................................. 42 Herbicides ............................................................................................................................. 45 Re-vegetation ........................................................................................................................ 47 Summary of Proposed Actions ................................................................................................. 50 Livestock and Wild Horse Management ................................................................................... 50 Cultural Resources .................................................................................................................... 51 Paleontological Resources ........................................................................................................ 51 Design Features and Conservation Measures ........................................................................... 52 Soils....................................................................................................................................... 52 Water Resources and Riparian Conservation Areas (RCAs) ................................................ 52 Special Status Aquatic Animal Species (TEP and BLM sensitive) ...................................... 56 Wildlife (General) ................................................................................................................. 58 Special Status Plants and Wildlife ........................................................................................ 59 Migratory Bird Species of Conservation Concern ................................................................ 75 Livestock ............................................................................................................................... 77 Wild Horses .......................................................................................................................... 77 Native American Traditional Use Areas ............................................................................... 78 Human Health and Safety ..................................................................................................... 78 Special Management Areas ................................................................................................... 78 Travel Management .............................................................................................................. 80 Monitoring ................................................................................................................................ 81 No Action Alternative - Continue Present Herbicide Use ........................................................ 82 Alternatives Considered But Eliminated From Detailed Analysis ........................................... 82 No Use of Herbicides ............................................................................................................ 82 No Aerial Application of Herbicides .................................................................................... 83 CHAPTER 3 – AFFECTED ENVIRONMENT AND ANALYSIS OF IMPACTS .................... 84 Soils........................................................................................................................................... 86 Affected Environment ........................................................................................................... 86 Environmental Impacts ......................................................................................................... 86 Proposed Action Impacts – Soils .......................................................................................... 86 No Action Alternative Impacts – Soils ................................................................................. 90 Cumulative Effects – Soils.................................................................................................... 91 Water Quality ............................................................................................................................ 92 Affected Environment ........................................................................................................... 92 Environmental Impacts ......................................................................................................... 92 Proposed Action Impacts – Water Quality ........................................................................... 93 No Action Alternative Impacts – Water Quality .................................................................. 98 Cumulative Effects – Water Quality ..................................................................................... 99 Air Quality .............................................................................................................................. 100 Affected Environment ......................................................................................................... 100 Environmental Impacts ....................................................................................................... 103 Proposed Action Impacts – Air Quality .............................................................................. 103 No Action Alternative Impacts – Air Quality ..................................................................... 104 Cumulative Effects – Air Quality ......................................................................................