Effects of Road and Transmission-Line Rights-of-Way on Botanical Resources

Brett C. Dumas Landscape Ecologist Gary L. Holmstead Ecologist Marie J. J. Kerr Botanical Technician Leslie B. Carpenter Wildlife Technician

Technical Report Appendix E.3.3-4 September 2002 Revised July 2003 Complex FERC No. 1971 Copyright © 2003 by Power Company

Idaho Power Company Effects of Road and Transmission Line

TABLE OF CONTENTS

Table of Contents ...... i

List of Tables...... iv

List of Figures ...... ix

List of Appendices ...... xv

Executive Summary ...... 1

1. Introduction ...... 6

1.1. State of Knowledge ...... 6

1.1.1. Existing Vegetation Data ...... 6

1.1.2. Operation and Maintenance Procedures...... 7

1.1.3. Effects of Transmission Lines and Service Roads on Vegetation ...... 8

1.1.4. Landscapes and Landscape Processes...... 9

1.2. Objectives...... 10

2. Study Area...... 11

2.1. Location...... 11

2.2. Climate ...... 11

2.3. Geology ...... 12

2.4. Vegetation ...... 13

2.5. Jurisdiction ...... 13

3. Methods...... 13

3.1. Cover Type Mapping ...... 13

3.1.1. Rights-of-Way...... 14

3.1.2. Corridor ...... 15

3.1.3. Landscape Regions...... 15

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3.2. Surveys along Rights-of-Way and Service Roads ...... 16

3.2.1. Rare ...... 17

3.2.2. Noxious Weeds ...... 18

3.2.3. Disturbance Activities...... 19

3.3. Operation and Maintenance Activities...... 19

3.4. Analysis of Transmission Line Effects on Vegetation...... 20

3.4.1. Rights-of-Way Effects on Landscape Level Vegetation Patterns...... 20

3.4.2. Operation and Maintenance Effects on Vegetation...... 21

3.4.3. Rights-of-Way Clearance Studies ...... 22

4. Results / Discussion ...... 25

4.1. Cover Type Mapping ...... 25

4.1.1. Rights-of-Way...... 25

4.1.2. Corridor ...... 27

4.1.3. Landscape Regions...... 28

4.2. Surveys along Right-of-Way and Service Roads...... 34

4.2.1. Rare Plants...... 34

4.2.2. Noxious Weeds ...... 42

4.2.3. Disturbances...... 49

4.3. Operation and Maintenance Activities...... 66

4.4. Transmission Line Effects on Vegetation ...... 72

4.4.1. Rights-of-Way Effects on Landscape Level Vegetation Patterns...... 72

4.4.2. Operation and Maintenance Effects on Vegetation...... 77

4.4.3. Rights-of-Way Clearance Studies ...... 80

5. Conclusions / Management Implications ...... 83

5.1. Impacts on General Vegetation...... 83

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5.1.1. Rights-of-Way Effects on Landscape-Level Vegetation Patterns...... 83

5.1.2. Operation and Maintenance Effects on Vegetation...... 84

5.2. Impacts on Rare Plants...... 86

5.2.1. Rare Plant Species...... 86

5.2.2. Management Implications for Rare Plants...... 90

5.3. Noxious Weeds ...... 91

5.3.1. Noxious Weed Species...... 92

5.3.2. Distribution of Major Noxious Weed Occurrences ...... 100

5.3.3. Major Disturbance Types Associated With Noxious Weed Occurrences...... 101

5.3.4. Management Implications for Noxious Weeds...... 101

6. Acknowledgments...... 103

7. Literature Cited ...... 103

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LIST OF TABLES

Table 1. Transmission lines to be relicensed with the Hells Canyon Complex...... 115

Table 2. Linear length (Kilometers) of land ownership in Hells Canyon Complex transmission-line rights-of-way...... 116

Table 3. Kilometers of Hells Canyon Complex transmission-line service roads on public land and portions that were surveyed and those that were not surveyed (subsampled or missed)...... 117

Table 4. Linear length (Kilometers) of cover types on public and IPC lands in the Hells Canyon Complex transmission-line rights-of-way...... 118

Table 5. Proportion (%) of cover types on public and IPC lands traversed by the Hells Canyon Complex transmission lines...... 119

Table 6. Proportion (%) of grouped Idaho GAP cover types in the Hells Canyon Complex 10-km wide transmission lines corridor and associated landscape regions...... 120

Table 7. Frequency of rare plant occurrences within the road, within the 50-m buffer zone and beyond the buffer zone of Hells Canyon Complex transmission-line service roads...... 121

Table 8. Occurrence summaries and community distributions for Allium aaseae located during surveys of Hells Canyon Complex transmission-line service roads...... 121

Table 9. Disturbance intensitiesa for units associated with Allium aaseae occurrences located during surveys of Hells Canyon Complex transmission-line service roads...... 121

Table 10. Occurrence summaries and community distributions for Astragalus atratus var. inseptus located during surveys of Hells Canyon Complex transmission-line service roads...... 122

Table 11. Disturbance intensitiesa for units associated with Astragalus atratus var. inseptus occurrences located during surveys of Hells Canyon Complex transmission-line service roads...... 123

Table 12. Occurrence summaries and community distributions for Astragalus atratus var. owyheensis located during surveys of Hells Canyon Complex transmission-line service roads...... 124

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Table 13. Disturbance intensitiesa for units associated with Astragalus atratus var. owyheensis occurrences located during surveys of Hells Canyon Complex transmission-line service roads...... 124

Table 14. Occurrence summaries and community distributions for Astragalus purshii var. ophiogenes located during surveys of Hells Canyon Complex transmission-line service roads...... 124

Table 15. Disturbance intensitiesa for units associated with Astragalus purshii var. ophiogenes occurrences located during surveys of Hells Canyon Complex transmission-line service roads...... 125

Table 16. Occurrence summaries and community distributions for Bolandra oregana located during surveys of Hells Canyon Complex transmission-line service roads...... 125

Table 17. Disturbance intensitiesa for units associated with Bolandra oregana occurrences located during surveys of Hells Canyon Complex transmission-line service roads...... 125

Table 18. Occurrence summaries and community distributions for Carex backii located during surveys of Hells Canyon Complex transmission-line service roads...... 126

Table 19. Disturbance intensitiesa for units associated with Carex backii occurrences located during surveys of Hells Canyon Complex transmission-line service roads...... 126

Table 20. Occurrence summaries and community distributions for Mimulus clivicola located during surveys of Hells Canyon Complex transmission-line service roads...... 127

Table 21. Disturbance intensitiesa for units associated with Mimulus clivicola located during surveys of Hells Canyon Complex transmission-line service roads...... 127

Table 22. Occurrence summaries and community distributions for Rubus bartonianus located during surveys of Hells Canyon Complex transmission-line service roads...... 127

Table 23. Disturbance intensitiesa for units associated with Rubus bartonianus occurrences located during surveys of Hells Canyon Complex transmission-line service roads...... 128

Table 24. Occurrence summaries and community distributions for Stylocline filaginea located during surveys of Hells Canyon Complex transmission-line service roads...... 129

Hells Canyon Complex Page v Effects of Road and Transmission Line Idaho Power Company

Table 25. Disturbance intensitiesa for units associated with Stylocline filaginia occurrences located during surveys of Hells Canyon Complex transmission-line service roads...... 129

Table 26. Number of units containing records of each of the noxious weed species located during surveys of Hells Canyon Complex transmission-line service roads...... 130

Table 27. Number of units, per line, containing each of the 17 noxious weed species located during surveys of Hells Canyon Complex transmission-line service roads...... 131

Table 28. Summary of activity types on 146 Hells Canyon Complex transmission-line service road survey units containing Cardaria draba...... 132

Table 29. Summary of activity types on 29 Hells Canyon Complex transmission-line service road survey units containing Centaurea diffusa...... 133

Table 30. Summary of activity types on 212 Hells Canyon Complex transmission-line service road survey units containing Chondrilla juncea...... 134

Table 31. Summary of activity types on 101 Hells Canyon Complex transmission-line service road survey units containing Cirsium arvense...... 135

Table 32. Summary of disturbance types on 10 Hells Canyon Complex transmission-line service road survey units containing Conium maculatum...... 136

Table 33. Summary of activity types on 75 Hells Canyon Complex transmission-line service road survey units containing Convolvulus arvensis...... 137

Table 34. Summary of activity types on 160 Hells Canyon Complex transmission-line service road survey units containing Cynoglossum officinale...... 138

Table 35. Summary of activity types on 39 Hells Canyon Complex transmission-line service road survey units containing Dipsacus sylvestris...... 139

Table 36. Summary of activity types on 7 Hells Canyon Complex transmission-line service road survey units containing Euphorbia esula...... 140

Table 37. Summary of activity types on 69 Hells Canyon Complex transmission-line service road survey units containing Hypericum perforatum...... 141

Table 38. Summary of activity types on 157 Hells Canyon Complex transmission-line service road survey units containing Onopordum acanthium...... 142

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Table 39. Summary of activity types on 41 Hells Canyon Complex transmission-line service road survey units containing Rumex crispus...... 143

Table 40. Summary of activity types on 64 Hells Canyon Complex transmission-line service road survey units containing Taeniatherum caput-medusae...... 144

Table 41. Summary of agricultural disturbance intensities along Hells Canyon Complex transmission-line service roads...... 145

Table 42. Summary of big game disturbance intensities along Hells Canyon Complex transmission-line service roads...... 145

Table 43. Summary of corridor-clearing disturbance intensities along Hells Canyon Complex transmission-line service roads...... 146

Table 44. Summary of fire disturbance intensities along Hells Canyon Complex transmission-line service roads...... 146

Table 45. Summary of industrial disturbance intensities along Hells Canyon Complex transmission-line service roads...... 147

Table 46. Summary of livestock grazing disturbance intensities along Hells Canyon Complex transmission-line service roads...... 147

Table 47. Summary of logging disturbance intensities along Hells Canyon Complex transmission-line service roads...... 148

Table 48. Summary of non-project road disturbance intensities along Hells Canyon Complex transmission-line service roads...... 148

Table 49. Summary of off-highway vehicle disturbance intensities along Hells Canyon Complex transmission-line service roads...... 149

Table 50. Summary of residential disturbance intensities along Hells Canyon Complex transmission-line service roads...... 149

Table 51. Summary of road use intensities along Hells Canyon Complex transmission-line service roads...... 150

Table 52. Summary of service road disturbance intensities along Hells Canyon Complex transmission-line service roads...... 150

Table 53. Summary of water erosion disturbance intensities along Hells Canyon Complex transmission-line service roads...... 151

Table 54. Summary of disturbance types and intensities on Hells Canyon Complex transmission-line survey units (%) on Line 903...... 151

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Table 55. Summary of disturbance types and intensities on Hells Canyon Complex transmission-line survey units (%) on Line 904...... 152

Table 56. Summary of disturbance types and intensities on Hells Canyon Complex transmission-line survey units (%) on Line 905...... 152

Table 57. Summary of disturbance types and intensities on Hells Canyon Complex transmission-line survey units (%) on Line 906...... 153

Table 58. Summary of disturbance types and intensities on Hells Canyon Complex transmission-line survey units (%) on Line 907...... 153

Table 59. Summary of disturbance types and intensities on Hells Canyon Complex transmission-line survey units (%) on Line 908...... 154

Table 60. Summary of disturbance types and intensities on Hells Canyon Complex transmission-line survey units (%) on Line 910...... 154

Table 61. Summary of disturbance types and intensities on Hells Canyon Complex transmission-line survey units (%) on Line 911...... 155

Table 62. Summary of disturbance types and intensities on Hells Canyon Complex transmission-line survey units (%) on Line 912...... 155

Table 63. Summary of disturbance types and intensities on Hells Canyon Complex transmission-line survey units (%) on Line 913...... 156

Table 64. Summary of disturbance types and intensities on Hells Canyon Complex transmission-line survey units (%) on Line 951...... 156

Table 65. Hells Canyon Complex transmission-line maintenance activities on a line- by-line basis...... 157

Table 66. Regional summary of hectares and number of vegetation patches intersecting Hells Canyon Complex transmission line rights-of-way (ROW) and comparison areas (1 km out from either side of the ROW). The Idaho Canyon/Mountain region has only an east side...... 161

Table 67. Plain region composition of cover types intersecting the transmission line rights-of-way (ROW) and comparison areas (1 km out from either side of the ROW). Cover types present but contributing less than 0.1% to dominance are shown as 0...... 162

Table 68. Snake River Plateau Region composition of cover types intersecting the transmission line rights-of-way (ROW) and comparison areas (1 km out from either side of the ROW). Cover types present but contributing less than 0.1% to dominance are shown as 0...... 163

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Table 69. Payette Region composition of cover types intersecting the transmission line rights-of-way (ROW) and comparison areas (1 km out from either side of the ROW). Cover types present but contributing less than 0.1% to dominance are shown as 0...... 164

Table 70. Idaho Canyon/Mountain region composition of cover types intersecting the transmission line rights-of-way (ROW) and comparison areas (1 km to the east of the ROW). Cover types present but contributing less than 0.1% to dominance are shown as 0...... 165

Table 71. Wallowa Whitman National Forest composition of cover types intersecting the transmission line rights-of-way (ROW) and comparison areas (1 km out from either side of the ROW). Cover types present but contributing less than 0.1% to dominance are shown as 0...... 166

Table 72. Activity Index ratings for Hells Canyon Complex transmission lines...... 167

Table 73. Number of service road and tower survey units and rare plant and noxious weed occurrences, by risk category, associated with Hells Canyon Complex transmission...... 167

Table 74. Distribution of survey unit Risk Index ratings for each Hells Canyon Complex transmission line...... 168

Table 75. Rare plant occurrences located on Hells Canyon Complex transmission-line service road survey units with moderate or highest Risk Index Categories...... 169

Table 76. Meters of cover types in forest region Hells Canyon Complex transmission-line rights-of-way that are different from cover types outside the rights-of-way...... 170

Table 77. Snag, large tree, and log characteristics in two zones adjacent to Hells Canyon Complex transmission lines rights-of-way in the forested region of the Wallowa Whitman National Forest...... 171

Table 78. Meters of riparian habitat and proportion trimmed/cut on public land transmission line rights-of-way for the Hells Canyon Complex...... 171

LIST OF FIGURES

Figure 1. Transmission lines associated with Hells Canyon Complex relicensing...... 173

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Figure 2. Formula for calculating (a) the operation and maintenance (O & M) Activity Index and (b) the O & M Risk Index for Hells Canyon Complex transmission lines and service roads...... 175

Figure 3. Transect layout used for snag, large tree, and log surveys along Hells Canyon Complex transmission line rights-of-way...... 176

Figure 4. Hells Canyon Complex transmission lines...... 177

Figure 5. Snake River Plain transmission line region major vegetation cover types...... 185

Figure 6. Snake River Plateau transmission line region major vegetation cover types...... 187

Figure 7. Payette Valley transmission line region major vegetation cover types...... 189

Figure 8. Major vegetation cover types in 4 Hells Canyon Complex transmission line landscape regions...... 191

Figure 9. Distribution of Allium aaseae in Idaho. Allium aaseae is endemic to with known populations in Ada, Boise, Gem, Payette, and counties. The species is on the Idaho Power Company priority search list for Idaho. It is not known to occur in ...... 193

Figure 10. Allium aaseae occurrences located during Idaho Power Company surveys...... 195

Figure 11. Distribution of Astragalus atratus var. inseptus in Idaho. Astragalus atratus var. inseptus is endemic to the north edge of the Snake River Plain, with known populations in Blaine, Camas, Elmore, Gooding, and Lincoln counties. The species is on the Idaho Power Company incidental search list for Idaho. It is not known to occur in Oregon...... 197

Figure 12. Astragalus atratus var. inseptus occurrences located during Idaho Power Company surveys...... 199

Figure 13. Distribution of Astragalus atratus var. owyheensis. Astragalus atratus var. owyheensis occurs within, and in regions immediately adjacent to, the Owyhee Desert, with known populations in Baker and Malheur counties in Oregon, Owyhee, Twin Falls, and Washington counties in Idaho, and Elko County, . The species is on the Idaho Power Company incidental search list for Oregon. It is not considered rare in Idaho...... 201

Figure 14. Astragalus atratus var. owyheensis occurrences located during Idaho Power Company surveys...... 203

Figure 15. Astragalus purshii var. ophiogenes occurrences located during Idaho Power Company surveys...... 205

Page x Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line

Figure 16. Bolandra oregana occurrences located during Idaho Power Company surveys...... 207

Figure 17. Distribution of Carex backii in Oregon. Carex backii occurs in southern British Columbia, northern Washington, and northeast Oregon, east to , Colorado, New York and Quebec. It is known to occur in Baker, Grant, Harney, Morrow, Umatilla, Union, and Wallowa counties in Oregon. The species is on the Idaho Power Company incidental search list for Oregon. It is not considered rare in Idaho...... 209

Figure 18. Carex backii occurrences located during Idaho Power Company surveys...... 211

Figure 19. Distribution of Mimulus clivicola in Idaho and Oregon. Mimulus clivicola occurs in northern Idaho and adjacent Washington, to the southern end of the Snake River Canyon where it occurs along the east slopes of the in Oregon, west into central Idaho. It is known to occur in Adams, Benwah, Clearwater, Idaho, Kootenai, Latah, Lewis, , Shoshone, Valley, and Washington counties in Idaho, and Baker and Wallowa counties in Oregon. The species is on the Idaho Power Company incidental search list for both Idaho and Oregon...... 213

Figure 20. Mimulus clivicola occurrences located during Idaho Power Company surveys...... 215

Figure 21. Distribution of Rubus bartonianus in Idaho and Oregon. Rubus bartonianus is endemic to the Snake River Canyon, occurring in thickets on canyon sides along Hells Canyon Reservoir and a few miles below Hells Canyon Dam. The species is on the Idaho Power Company priority search list for both Idaho and Oregon...... 217

Figure 22. Rubus bartonianus occurrences located during Idaho Power Company surveys...... 219

Figure 23. Distribution of Stylocline filaginea in Idaho. Stylocline filaginea occurs in and northeastern Nevada, north to the east Cascades of Oregon and portions of southern Idaho. The species is on the Idaho Power Company incidental search list for Idaho. It is not considered rare in Oregon...... 221

Figure 24. Stylocline filaginea populations located during Idaho Power Company surveys...... 223

Figure 25. Distribution of Cardaria draba in (a) Oregon and (b) Idaho...... 227

Figure 26. Distribution of Centaurea diffusa in (a) Oregon and (b) Idaho...... 227

Figure 27. Distribution of Chondrilla juncea in (a) Oregon and (b) Idaho...... 228

Hells Canyon Complex Page xi Effects of Road and Transmission Line Idaho Power Company

Figure 28. Distribution of Cirsium arvense in (a) Oregon and (b) Idaho...... 228

Figure 29. Distribution of Conium maculatum in (a) Oregon and (b) Idaho...... 229

Figure 30. Distribution of Convolvulus arvensis in (a) Oregon and (b) Idaho...... 229

Figure 31. Distribution of Cynoglossum officinale in Oregon...... 230

Figure 32. Distribution of Dipsacus sylvestris in Oregon...... 230

Figure 33. Distribution of Euphorbia esula in (a) Oregon and (b) Idaho...... 231

Figure 34. Distribution of Hypericum perforatum in Oregon...... 231

Figure 35. Distribution of Onopordum acanthium in (a) Oregon and (b) Idaho...... 232

Figure 36. Distribution of Rumex crispus in Oregon...... 232

Figure 37. Distribution of Taeniatherum caput-medusae in Oregon...... 233

Figure 38. Distribution of Aegilops cylindrica in (a) Oregon and (b) Idaho...... 233

Figure 39. Distribution of Centaurea maculosa in (a) Oregon and (b) Idaho...... 234

Figure 40. Distribution of Centaurea repens in (a) Oregon and (b) Idaho...... 234

Figure 41. Distribution of Tribulus terrestris in (a) Oregon and (b) Idaho...... 235

Figure 42. Agricultural disturbance intensities for Hells Canyon Complex transmission-line survey units. Total km surveyed per line are as follows: 903 = 67; 904 = 78; 905 = 27; 906 = 59; 907 = 30; 908 = 10; 910 = 9; 911 = 56; 912 = 77; 913 = 17; 951 = 76...... 236

Figure 43. Big game disturbance intensities for Hells Canyon Complex transmission-line survey units. Total km surveyed per line are as follows: 903 = 67; 904 = 78; 905 = 27; 906 = 59; 907 = 30; 908 = 10; 910: = 9; 911 = 56; 912 = 77; 913 = 17; 951 = 76...... 237

Figure 44. Corridor clearing disturbance intensities for Hells Canyon Complex transmission-line survey units. Total km surveyed per line are as follows: 903 = 67; 904 = 78; 905 = 27; 906 = 59; 907 = 30; 908 = 10; 910 = 9; 911 = 56; 912 = 77; 913 = 17; 951 = 76...... 238

Figure 45. Fire disturbance intensities for Hells Canyon Complex transmission-line survey units. Total km surveyed per line are as follows: 903 = 67; 904 = 78; 905 = 27; 906 = 59; 907 = 30; 908 = 10; 910: = 9; 911 = 56; 912 = 77; 913 = 17; 951 = 76...... 239

Page xii Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line

Figure 46. Industrial disturbance intensities for Hells Canyon Complex transmission-line survey units. Total km surveyed per line are as follows: 903 = 67; 904 = 78; 905 = 27; 906 = 59; 907 = 30; 908 = 10; 910: = 9; 911 = 56; 912 = 77; 913 = 17; 951 = 76...... 240

Figure 47. Livestock disturbance intensities for Hells Canyon Complex transmission-line survey units. Total km surveyed per line are as follows: 903 = 67; 904 = 78; 905 = 27; 906 = 59; 907 = 30; 908 = 10; 910: = 9; 911 = 56; 912 = 77; 913 = 17; 951 = 76...... 241

Figure 48. Logging disturbance intensities for Hells Canyon Complex transmission-line survey units. Total km surveyed per line are as follows: 903 = 67; 904 = 78; 905 = 27; 906 = 59; 907 = 30; 908 = 10; 910: = 9; 911 = 56; 912 = 77; 913 = 17; 951 = 76...... 242

Figure 49. Non-project road disturbance intensities for Hells Canyon Complex transmission-line survey units. Total km surveyed per line are as follows: 903 = 67; 904 = 78; 905 = 27; 906 = 59; 907 = 30; 908 = 10; 910: = 9; 911 = 56; 912 = 77; 913 = 17; 951 = 76...... 243

Figure 50. Off-highway vehicle disturbance intensities for Hells Canyon Complex transmission-line survey units. Total km surveyed per line are as follows: 903 = 67; 904 = 78; 905 = 27; 906 = 59; 907 = 30; 908 = 10; 910: = 9; 911 = 56; 912 = 77; 913 = 17; 951 = 76...... 244

Figure 51. Residential disturbance intensities for Hells Canyon hydroelectric complex transmission-line survey units. Total km surveyed per line are as follows: 903 = 67; 904 = 78; 905 = 27; 906 = 59; 907 = 30; 908 = 10; 910: = 9; 911 = 56; 912 = 77; 913 = 17; 951 = 76...... 245

Figure 52. Road use intensities for Hells Canyon Complex transmission-line survey units. Total km surveyed per line are as follows: 903 = 67; 904 = 78; 905 = 27; 906 = 59; 907 = 30; 908 = 10; 910: = 9; 911 = 56; 912 = 77; 913 = 17; 951 = 76...... 246

Figure 53. Service road disturbance intensities for Hells Canyon Complex transmission-line survey units. Total km surveyed per line are as follows: 903 = 67; 904 = 78; 905 = 27; 906 = 59; 907 = 30; 908 = 10; 910: = 9; 911 = 56; 912 = 77; 913 = 17; 951 = 76...... 247

Figure 54. Water erosion disturbance intensities for Hells Canyon Complex transmission-line survey units. Total km surveyed per line are as follows: 903 = 67; 904 = 78; 905 = 27; 906 = 59; 907 = 30; 908 = 10; 910: = 9; 911 = 56; 912 = 77; 913 = 17; 951 = 76...... 248

Figure 55. Kilometers of disturbance types by intensity categories observed on survey units of Hells Canyon Complex transmission line 903...... 249

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Figure 56. Kilometers of disturbance types by intensity categories observed on survey units of Hells Canyon Complex transmission line 904...... 250

Figure 57. Kilometers of disturbance types by intensity categories observed on survey units of Hells Canyon Complex transmission line 905...... 251

Figure 58. Kilometers of disturbance types by intensity categories observed on survey units of Hells Canyon Complex transmission line 906...... 252

Figure 59. Kilometers of disturbance types by intensity categories observed on survey units of Hells Canyon Complex transmission line 907...... 253

Figure 60. Kilometers of disturbance types by intensity categories observed on survey units of Hells Canyon Complex transmission line 908...... 254

Figure 61. Kilometers of disturbance types by intensity categories observed on survey units of Hells Canyon Complex transmission line 910...... 255

Figure 62. Kilometers of disturbance types by intensity categories observed on survey units of Hells Canyon Complex transmission line 911...... 256

Figure 63. Kilometers of disturbance types by intensity categories observed on survey units of Hells Canyon Complex transmission line 912...... 257

Figure 64. Kilometers of disturbance types by intensity categories observed on survey units of Hells Canyon Complex transmission line 913...... 258

Figure 65. Kilometers of disturbance types by intensity categories observed on survey units of Hells Canyon Complex transmission line 951...... 259

Figure 66. Snake River Plain region: Idaho grouped GAP vegetation patches intersecting the ROW and comparison areas 1 km to either side...... 261

Figure 67. Snake River Plateau region: Idaho grouped GAP vegetation patches intersecting the ROW and comparison areas 1 km to either side...... 263

Figure 68. Payette Valley region: Idaho grouped GAP vegetation patches intersecting the ROW and comparison areas 1 km to either side...... 265

Figure 69. Idaho Canyon/Mountain region: Idaho grouped GAP vegetation patches intersecting the ROW and comparison areas 1 km to the east...... 267

Figure 70. WWNF region: WWNF grouped vegetation patches intersecting the ROW and comparison areas 1 km to either side...... 269

Page xiv Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line

LIST OF APPENDICES

Appendix 1. Idaho GAP vegetation cover types and their relation to other vegetation coverages used for the Hells Canyon Complex transmission line rights-of- way and corridor cover type maps...... 271

Appendix 2. Hells Canyon Complex transmission-line service road survey units...... 279

Appendix 3. Definitions of relative species abundance ratings used for Idaho Power Company rare plant and noxious weed surveys of Hells Canyon Complex transmission line survey units...... 373

Appendix 4. Form and instructions for Idaho Power Company rare plant and noxious weed surveys of Hells Canyon Complex transmission-line survey units...... 375

Appendix 5. Special status plants considered for Idaho Power rare plant surveys of Hells Canyon Complex transmission lines and service roads...... 379

Appendix 6. Definition of federal and state rare species ranks (IDCDC 2001b, ORNHP 2001a)...... 385

Appendix 7. Idaho Conservation Data Center and Oregon Natural Heritage Program element occurrence forms for rare plant species...... 389

Appendix 8. Noxious weed species considered for Idaho Power surveys of Hells Canyon Complex transmission lines and service roads...... 393

Appendix 9. Definitions of disturbance types and intensities used for Idaho Power rare plant and noxious weed surveys of Hells Canyon Complex transmission lines and service roads...... 395

Appendix 10. Idaho Power Company rare plant and noxious weed survey results along Hells Canyon Complex transmission-line service roads. Appendices 3, 4, 5, 8, and 9 provide code explanations...... 401

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Page xvi Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line

EXECUTIVE SUMMARY

Idaho Power Company (IPC) is in the process of relicensing its Hells Canyon Complex (HCC) with the Federal Energy Regulatory Commission. Associated with the complex are 1,061 km (659 mi) of transmission lines, which extend from the HCC southeast across the Snake River Plain to American Falls and northwest across the Wallowa Mountains to Enterprise, Oregon. This report collects the findings from a suite of integrated studies that addressed botanical resources along the transmission-line corridors and associated service roads, including general vegetation cover and plant communities, rare plants, and noxious weeds. This report describes these resources and addresses the concerns about possible project impacts that have been expressed by federal and state resource agencies and concerned nongovernmental groups and defined in cooperation with the Terrestrial Resources Work Group of the Collaborative Team.

Specific objectives of this study were to 1) identify and describe IPC service roads and transmission-line rights-of-way (ROW) associated with the HCC; 2) identify and describe operational and maintenance (O&M) activities occurring within these ROW; 3) identify specific issues related to O&M activities that influence botanical resources; 4) inventory general botanical resources, rare plants, and noxious weed species in the study area and evaluate the parameters that may influence the occurrence of these resources; 5) record the types of disturbance activities and the intensity of each disturbance type in the ROW and along associated service roads; 6) evaluate influences of O&M activities on general botanical resources, rare plants, and noxious weeds; and 7) recommend appropriate protection, mitigation, or enhancement measures to minimize IPC impacts to botanical resources.

In order to meet these objectives, we surveyed the transmission-line ROW and associated service roads during spring to summer in 1999 and 2000. We mapped locations for cover types, disturbances, rare plants, and noxious weeds. To map cover types outside the ROW, we used existing data. O&M activities associated with the ROW were described by activity type, location, duration, and timing. We determined the influence of O&M activities by reviewing the literature, analyzing the composition and spatial arrangement of cover types, and using an Activity Index and a Risk Index to represent two levels of potential O&M impacts for each transmission line. The spatial analysis describes vegetation patterns on the landscape, identifies the scale of impacts, and provides information on the potential for fragmentation of vegetation communities related to the transmission-line and service-road ROW. The indices are derived from simple statistical models, not from on-the-ground assessments of impacts, and are used as indicators of potential impacts or problem areas rather than as indicators of areas with known or imminent impacts to general vegetation resources, rare plants, or spread of noxious weeds.

General Vegetation In the eastern end of the study area, Transmission Lines 906, 912, and 951 cross the Snake River Plain from American Falls to Boise. These lines are the three longest in the HCC. The vegetation in their ROW is dominated by big sagebrush, perennial grassland, and annual grassland. Line 923, at the very eastern end of the study area, traverses only 0.4 km of public land. It crosses the Snake River just below American Falls Reservoir and passes through sagebrush,

Hells Canyon Complex Page 1 Effects of Road and Transmission Line Idaho Power Company riverine riparian, and barren land. Line 952 is a short tap off Line 951 and is entirely on privately owned agricultural land.

In the central portion of the study area, Lines 904 and 911 extend from Boise to Brownlee Dam, passing through foothill and mid-elevation habitats. Perennial and annual grasslands are the most common vegetation in the ROW, occurring on about two-thirds of the lines. Bitterbrush, montane shrub, and low sagebrush communities combined represent about one-fifth of the vegetation in the ROW. Big sagebrush is less common than on the eastern lines.

At the western extent of the study area, Line 903 extends from Brownlee Substation near the dam to Baker City, Oregon. Communities of big sagebrush and perennial and annual grassland dominate these areas.

Lines 905 and 945 are entirely within Hells Canyon. Line 905 runs along the eastern shore of Oxbow Reservoir from Brownlee Dam to Oxbow Dam. Line 945 runs along the eastern shore of Hells Canyon Reservoir from Oxbow Dam to Hells Canyon Dam. The vegetation along Line 905 is composed primarily of perennial grass, annual grass, and bitterbrush. In contrast, Line 945 runs adjacent to a paved road, and its vegetation is mostly classified as disturbed habitat.

Line 907 extends downstream from Oxbow Dam along the west side of Hells Canyon Reservoir for about half its length before climbing into the forested WWNF and ending at Pallette Junction on the Imnaha River. The canyon portion of the line is largely in bitterbrush and perennial grassland. As the line climbs into higher elevations, it crosses through montane shrub, alpine shrub, and dry and wet meadows. Areas of forested vegetation occur where the line spans across valleys, which allow for tall trees without interference to the lines. Line 907 then crosses and runs parallel to the Imnaha River for about 7 km. This area is primarily composed of riverine riparian habitat.

The three remaining project lines—908, 910, and 913—radiate from Pallette Junction at the Imnaha River. Lines 908 and 910 are completely in the Hells Canyon National Recreation Area (HCNRA). Line 913 is in the HCNRA for only 2 km. Line 908 continues north 15 km along the river to the town of Imnaha through mostly private land. The vegetation is mostly perennial grassland, with patches of Douglas-fir, montane shrub, and riverine riparian habitat. Line 910 heads east 13 km before dropping to the Hells Canyon Dam. The Hells Canyon Wilderness Area surrounds the line for the last 5 km. The vegetation in the ROW is dominated by perennial grassland and montane shrub. Less common cover types are Douglas-fir, white fir, and rock. Line 913 heads west to Enterprise. ROW vegetation composition is similar to that of Lines 908 and 913, with a mixture of perennial grassland, alpine and montane shrub, Douglas-fir, and dry meadow.

There is little evidence that the transmission-line and service-road ROW are affecting vegetation composition or pattern in most regions of the study area. Much of the shrub-steppe ecosystem in the study area has departed significantly from historical composition levels and patterns and continues to be fragmented by landscape-level processes, including livestock grazing, fire, and land use conversion.

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Clearing of tall vegetation in the ROW has had an effect on vegetation patterns in forested areas of the Wallowa-Whitman National Forest. However, the impacts are confined to the ROW, and such clearing is not causing fragmentation of forest communities. Vegetation clearing occurs on about 23 km of transmission-line ROW. Along the Imnaha River, vegetation clearing occurs on approximately 4.3 ha, of which 0.6 ha is riparian vegetation. Snag (standing, dead tree), large-tree, and downed-wood resources are lacking in the ROW that are cleared. Trees and snags that may interfere with the transmission lines are routinely cleared from the “hazard area” adjacent to the ROW. This hazard area buffers both sides of the ROW for about 30 m. Otherwise, vegetation in this zone is not disturbed when line clearing occurs. When we compared the hazard zone with a control area, we found no difference in large-tree and downed- wood resources and a moderate decrease in snag resources in the hazard zone.

IPC could potentially reduce the impact of vegetation clearing along the Imnaha River by developing a more detailed vegetation management plan. Such a plan would probably recommend a more frequent, less intensive clearing cycle to promote more riparian vegetation development beneath the lines, while also maintaining system reliability and safety. To provide managers with better spatial information on where and when clearing is likely to be needed, growth rates of vegetation communities below Line 907 could be studied and mapped in relation to conductor sag levels. To mitigate impacts to riparian patches that must be cleared, trees and other tall-growing vegetation could be promoted or planted in riparian areas outside of the ROW where riparian resources are deficient.

Because of a lack of large tree resources within cleared ROW, there is no direct recruitment of snags and large woody material. Because the ROW must be cleared of trees and snags that are hazardous to the safety and to the reliability of the transmission lines, these low-wood conditions will persist in the future. IPC could reduce the potential impacts to wood resources within the hazard zone by implementing a timely hazard tree removal program to remove only those trees and snags having a high likelihood of interfering with the transmission lines. By leaving cut trees and snags on site, recruitment of large downed wood within the hazard zone should be adequate.

Rare Plants Prior to field research, IPC, in consultation with the Terrestrial Resources Work Group, developed lists of special status plant species to be considered during transmission-line surveys. Twenty-seven search species and 43 incidental species were designated for Idaho, while 25 search species and 37 incidental species were designated for Oregon. Rare plant surveys were conducted along service roads, at tower sites, and in ROW clearing areas occurring on public lands along all transmission lines associated with the HCC. A total of 785 survey units, totaling 694 km, occurred on public land. For each survey unit, botanists recorded all rare plants and noxious weed species. Relative abundance of each species was recorded for the following three zones: 1) on the immediate roadbed or tower pad location, 2) within 50 m of the roadbed or pad location, and 3) in the area farther than 50 m from the roadbed or pad location. The types of disturbance present in each survey unit and the intensity of each disturbance type were recorded, as were general observations regarding disturbance, wildlife, rare plant or noxious weed occurrences, effects of transmission-line O&M activities, and trend and condition of survey unit areas.

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We located 63 occurrences of 9 rare plant species along survey units. No federally listed threatened or endangered plant species were found. In Idaho, we located 3 occurrences of Allium aaseae (Aase’s onion), 19 occurrences of Astragalus atratus var. inseptus (mourning milkvetch), 10 occurrences of Rubus bartonianus (bartonberry), 13 occurrences of Stylocline filaginea (hooked stylocline), and 2 suspected occurrences of Astragalus purshii var. ophiogenes (Snake River milkvetch). In Oregon, we located 4 occurrences of Astragalus atratus var. owyheensis (Owyhee milkvetch), 1 occurrence of Bolandra oregana (Oregon bolandra), 10 occurrences of Carex backii (Back’s sedge), and 1 occurrence of Mimulus clivicola (bank monkeyflower).

Within the study area, livestock grazing and fire disturbance pose the most imminent threats to rare plant occurrences. Livestock disturbance was listed as an imminent threat to occurrences of Carex backii located during surveys. Livestock was also considered to be a possible threat to occurrences of Allium aaseae, Astragalus atratus var. inseptus, Astragalus purshii var. ophiogenes, and Stylocline filaginea. Fire disturbance was considered to pose a threat to occurrences of Astragalus atratus var. inseptus and Stylocline filaginea in portions of the study area southeast of Brownlee Dam. In addition to livestock and fire disturbance, big game disturbance was noted to pose a slight threat to one occurrence of Astragalus atratus var. inseptus and a potential threat to one occurrence of Mimulus clivicola, and road use, off-highway vehicle use, service road construction, and non-project road disturbance were noted to pose potential threats to one occurrence of Carex backii. All other disturbance types were considered to have little negative impact on rare plant occurrences.

Conservation of rare plants in the study area may involve several measures, depending on the natural history of the species and on our knowledge of the dynamics of the occurrences and of threats to species occurrences. Protecting plants from physical disturbance, controlling encroaching weed species, and monitoring species occurrences are a few of the many conservation and enhancement measures that may be taken.

We found 38 rare plant occurrences within service-road ROW. Eighteen rare plant occurrences were located in survey units with a moderate or high potential of being disturbed by O&M activities. In general, we recommend working cooperatively with natural resource land management agencies to protect rare plant sites threatened by disturbance activities. Specific actions to minimize impacts from IPC activities should include implementing a comprehensive O&M plan that would include the following:

• Develop measures to reduce the potential spread of noxious weeds, which could displace rare plants • Protect existing occurrences from O&M disturbances through timing restrictions, avoidance measures, road improvements, and education and communication with IPC personnel and contractors • Survey for new sites when implementing major O&M activities • Monitor impacts following major O&M activities • Implement road maintenance best management practices

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Noxious Weeds Prior to field research, IPC, in consultation with appropriate agencies and the Terrestrial Resources Work Group, compiled lists of noxious weed species for which to survey: 35 for Idaho and 26 for Oregon. Botanists conducted surveys for noxious weeds while also surveying for rare plants, using similar methods and protocols for the two surveys.

IPC botanists recorded 1,118 occurrences of 17 different noxious weed species on survey units within the study area. At least 1 noxious weed was located on 607 of 785 units surveyed (77%). Five of the 17 species of weeds located occurred on 10% or more of units surveyed. Chondrilla juncea was most commonly recorded, occurring on 27% of the survey units, followed by Cynoglossum officinale and Onopordum acanthium, both present on 20%; Cardaria draba, present on 19%; and Cirsium arvense, present on 13%.

Service road condition and livestock grazing were the major disturbance types present on survey units where noxious weed species were recorded. Big game and water erosion were major disturbance factors in many areas. Corridor clearing, fire, off-highway vehicles, and non-project road use were site-specific disturbance factors. Agriculture, industry, logging, and residential use were not major disturbance factors associated with noxious weeds. Because disturbance types and intensities were rated on qualitative scales, the responses of noxious weeds to disturbance factors were not directly evaluated. Of the four most common disturbance types, service road disturbance is the only one directly related to IPC activities.

Because of the complexity of the spread and establishment of weedy species, it is difficult to make inferences about direct or indirect impacts of individual disturbance types in relation to the presence of noxious weeds. Within the study area, widespread disturbance types, including service road construction, livestock, big game, non-project roads, off-highway vehicles, road use, and water erosion, cannot easily be related to noxious weed invasions.

We recommend working cooperatively with land management agencies and other private landowners to control establishment and spread of noxious weeds. Specifically, we recommended participating with local Cooperative Weed Management Areas for the areas traversed by transmission-line ROW. These groups build cooperative relationships among agencies, landowners, land managers, and other interested individuals and organizations— relationships that are needed for effective management of noxious weeds. Specific actions to minimize impacts from IPC activities should include implementing a comprehensive O&M plan that would recommend the following:

• Clean vehicles that travel off-road or disturb soil and that are likely to spread noxious weed seeds • Promptly reseed areas following disturbance to reduce the potential for weed invasion • Educate and communicate with IPC personnel and contractors regarding noxious weed control • Implement road maintenance best management practices

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1. INTRODUCTION

Idaho Power Company (IPC) is in the process of relicensing its Hells Canyon Complex (HCC) with the Federal Energy Regulatory Commission (FERC). Associated with the complex are 1,061 kilometers (km) (659 miles [mi]) of transmission lines, which extend from southeastern Idaho west across the Snake River Plain and northwest across the Wallowa Mountains to Enterprise, Oregon. Each line has a right-of-way (ROW) that is 15 to 46 meters (m) (50 to 150 feet [ft]) wide and various associated service roads to access the towers and facilities in the corridor. Fifty-four percent (568 km [352 mi]) of these lines cross public lands, which are the focus of this study. FERC requires that applicants seeking to relicense hydroelectric projects describe botanical resources in the vicinity of a project and impacts of that project on those resources (18CFR §4.41[f][3]). This report is a suite of integrated studies addressing botanical resource concerns along the transmission line corridors and associated service roads. The botanical resource components considered here include general vegetation cover and plant communities, rare plants, and noxious weeds. We describe these resources and address the concerns that have been expressed by federal and state resource agencies and concerned nongovernmental groups about possible project impacts. These concerns were defined in cooperation with the Terrestrial Resources Work Group (TRWG) of the Collaborative Team.

1.1. State of Knowledge

1.1.1. Existing Vegetation Data

1.1.1.1. General Vegetation Prior to this study, limited information on the botanical resources associated with the transmission lines was available. No specific studies had been conducted on the botanical resources of the transmission-line and service-road ROW. Though general botanical studies were conducted in the vicinity of the study area, they did not specifically focus on transmission-line corridors. Previous investigations characterized potential natural vegetation and the successional status of vegetation types (Tisdale 1979, Tisdale and Hironaka 1981, Tisdale 1986, Johnson and Simon 1987, Franklin and Dyrness 1988, Clausnitzer 1993, Crowe and Clausnitzer 1995). A few projects delineated localized plant communities in the vicinity of the transmission lines (Huschle 1975, Mancuso 1995a, Mancuso and Moseley 1995).

Recent vegetation mapping studies in Idaho and Oregon provide broad-scale information on the nature, extent, and spatial characteristics of plant communities. Gap analysis projects (GAP) that classify satellite thematic mapper data have produced digital land cover information for the two states. The Idaho land cover map was created using two separate classified images: one that encompasses northern Idaho (Redmond et al. 1996) and another that includes southern Idaho (Homer 1998). The southern Idaho map includes all of the transmission lines and is based on Landsat 5 thematic mapper scenes from 1995 to 1998. The Idaho land cover map is at 1:100,000 scale with a 2-hectare (ha) minimum mapping unit. There are 132 land cover classes.

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The Oregon GAP map is also at 1:100,000 scale but with a minimum mapping unit of 100 ha (Kiilsgaard 1999). It was created from 1991 to 1993 Landsat scenes. About 70 land cover classes are defined for the Oregon data. The Wallowa-Whitman National Forest (WWNF) produced a digital map of existing vegetation based on recent analyses of field data (e.g., stand exams) and interpretations of aerial photos. The scale of this vector data is 1:15,480, and the minimum mapping unit is 2.02 ha (5 acres) (WWNF 1999).

1.1.1.2. Rare Plants Rare plant species considered in this study may include those designated as species of conservation concern by the U.S. Fish and Wildlife Service (USFWS), Bureau of Land Management (BLM), U.S. Forest Service (USFS), Oregon Department of Agriculture (ODA), Idaho Native Plant Society (INPS), Idaho Conservation Data Center (IDCDC), and Oregon Natural Heritage Program (ORNHP).

Prior to this study, limited information regarding the occurrence, extent, and distribution of rare plants along the transmission-line corridors and associated service roads was available. In 1995, IPC had surveyed for rare plants along Line 905 as part of a maintenance project (Krichbaum 1995). No other specific studies had been conducted on rare plants along the transmission-line ROW. Though general botanical studies were conducted in the study area vicinity, they were not specifically focused on the transmission-line corridors or on rare plants. Incidental observations of rare plants have been recorded by various botanists in both Idaho and Oregon and are contained in databases maintained by the IDCDC and ORNHP.

1.1.1.3. Noxious Weeds In Idaho, noxious weeds are those plant species having the potential to cause injury to public health, crops, livestock, land, or other property; they are designated as noxious by the director of the state’s Department of Agriculture (Idaho Code §22-2272(8)). In Oregon, noxious weeds are those designated by the Oregon State Weed Board as injurious to public health, agriculture, recreation, wildlife, or any public or private property (Oregon State Department of Agriculture ORS 570). The responsibility for control or eradication rests not only on the private landowner but also on the county, state, and federal governments.

As with the other botanical resources, limited information regarding the occurrence, extent, and distribution of noxious weed species along the transmission-line corridors and associated service roads was available prior to this study. No specific studies had been conducted on noxious weeds along the transmission-line ROW. Land management agency botanists and county weed control employees have certainly recorded incidental observations of noxious weeds in both Idaho and Oregon, but no central database for such occurrences exists.

1.1.2. Operation and Maintenance Procedures

Industry restructuring, competition, and the 1996 outages caused by single trees contacting high-voltage transmission lines have all focused attention on the need to ensure reliability of the transmission systems of both individual utilities and the entire western interconnected grid. IPC maintains its transmission lines to ensure the structural and engineering integrity of the system

Hells Canyon Complex Page 7 Effects of Road and Transmission Line Idaho Power Company and to ensure the protection and safety of life and property. Providing safe, reliable power to customers requires an effective and timely operation and maintenance program. In addition, the Western System Coordinating Council has established reliability standards for IPC’s transmission-line system.

IPC performs a number of activities to keep its transmission lines operational and in good repair. These activities can be planned—such as those for routine patrols, inspections, scheduled maintenance, and scheduled emergency maintenance—or they can be unplanned—such as those for emergency maintenance in cases where public safety and property are threatened.

The timing of maintenance activities depends on the nature of the activity. Emergencies usually elicit an immediate response. Planned emergencies and routine maintenance are scheduled in coordination with system outage windows, when possible, to reduce power disruptions during high load periods. The scheduling of routine patrols is often based on a set schedule or as personnel are available. Maintenance may be scheduled annually, on a long-term schedule (e.g., 5- or 10-year cycles), or on an as-needed basis, depending on the activity.

Service roads are associated with most of the transmission-line ROW. These service roads were built to facilitate line construction and are now used to maintain the lines. Road types may vary from obscure two-track paths to those having well-defined gravel roadbeds. Roads necessary for the operation and maintenance of the transmission lines are categorized as either access roads or service roads. The sole purpose of service roads is to provide maintenance crews access to the transmission lines. These roads would not exist if the transmission lines did not exist. In contrast, access roads serve a broader purpose, such as contributing to agency (e.g., USFS), county, or state road systems. Access roads provide direct or indirect access to the transmission lines, but that access is not their primary purpose.

1.1.3. Effects of Transmission Lines and Service Roads on Vegetation

IPC operations and maintenance may directly and indirectly affect botanical resources in transmission-line and road ROW. These botanical resources can be impacted directly by IPC construction or maintenance activities; for example, vegetation can be modified in the ROW or displaced by roadbeds and structure locations (i.e., pole and tower pads). Indirect activities are those that are unrelated to IPC operation and maintenance activities and not necessarily associated with the existence of a transmission line. The effects of indirect activities on vegetation in the ROW may be numerous but difficult to quantify. Passing workers, motorists, livestock, wildlife, or recreationists can impact vegetation.

Vegetation must be cleared in forested habitats before transmission lines can be constructed. This clearing promotes earlier seral plant communities. After line construction, vegetation in the ROW is then managed to prevent trees and tall shrubs from interfering with line function and maintenance (Bramble and Byrnes 1983). Vegetation can interfere with electric power flow, pose safety problems, or interfere with maintenance activities. Vegetation that could create hazards are typically tall shrubs, trees, or snags that are within or adjacent to the ROW and that have a high probability of reaching or falling on power lines (called hazard trees). Such vegetation is identified during routine line inspections and removed annually. Traditionally, management activities aimed at maintaining a low-growing plant community in the ROW have included

Page 8 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line spraying of herbicides, cutting, or mowing. More recently, integrated vegetation management concepts, including cultural and biological management methods, have also been applied (Morrow 1997). Routine ROW vegetation management occurs on a cyclical schedule, such as every five or ten years.

Numerous researchers have studied ROW vegetation characteristics (Champlin 1973, Vasek et al. 1975, Beley et al. 1982, Hessing and Johnson 1982, Loney and Hobbs 1991, Luken et al. 1992, Brown 1994). In forested habitats, vegetation management of ROW creates a corridor of earlier successional vegetation and, thus, an edge effect on each side. This edge effect has been primarily studied at forest edges abutting pastures or clear-cuts. Compared with forest interiors, forest edges typically have 1) increased solar radiation (Kapos 1989, Chen et al. 1993, Saunders et al. 1998, Chen et al. 1999), 2) lower humidity and higher air temperature (Kapos 1989, Williams-Linera 1990, Chen et al. 1999), 3) higher soil temperatures (Saunders et al. 1998), and 4) increased wind speed (Raynor 1971). Each component of the microclimatic environment exhibits unique spatial and temporal responses to changes in structural elements (Chen et al. 1999). Therefore, vegetation boundaries defined by microclimatic criteria are not always the same as those defined by structural criteria (Chen et al. 1996).

These changes brought about by edge creation, in turn, alter the composition and structure of plant communities. Forest edges generally have higher stem density than do forest interiors (Wales 1972, Ranney et al. 1981, Whitney and Runkle 1981), a greater proportion of shade-intolerant species and exotic species (Wales 1972, Whitney and Runkle 1981, Ranney et al. 1981), and greater species richness (Brothers and Spingarn 1992). North-facing edges also differ from south-facing edges, presumably because of higher solar radiation at south-facing edges (Wales 1972, Palik and Murphy 1990). Similar results have been found in studies of transmission-line ROW (Luken et al. 1991, Luken et al. 1992, Brown 1994, Brisson et al. 1997).

In non-forested shrub-steppe environments, impacts of the transmission lines on vegetation are usually limited to ground disturbance from constructing and maintaining structures and service roads. The level of disturbance depends on the type of activity, engineering characteristics, surface material, and topography of the roads or structures. Roads may function as vectors for the spread of weeds (Brothers and Spingarn 1992, Tyser and Worley 1992). Roads that are frequently used or that are established on erodible soils create a dynamic environment of barren soils that are especially conducive for the establishment of early successional species, including those considered weeds. Once a roadway or corridor is established, passing workers, motorists, wildlife, or recreationists may introduce aggressive exotic species. Once present, these weeds can invade adjacent native habitats (MacLellan and Stewart 1986) and displace native species, including rare species. In addition, vehicles may disperse weeds (Sheley et al. 1999a).

1.1.4. Landscapes and Landscape Processes

Activities that are unrelated to IPC activities also affect botanical resources within and adjacent to the transmission line ROW. Large-scale processes, including fire, livestock grazing, timber harvest, and land status conversions, may influence vegetation in the ROW. Before causative factors for vegetation composition and condition in the ROW and associated landscape can be determined, local and landscape processes and impacts must be evaluated.

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On the Snake River Plain, much of the native shrub-steppe has been converted to annual grasslands dominated by introduced species (Whisenant 1990, Knick and Rotenberry 1995, Knick and Rotenberry 1997). The establishment of exotic aliens, especially Bromus tectorum (cheatgrass), has increased fire frequency, which in turn has converted more plant communities to annual grasslands (Whisenant 1990, Peters and Bunting 1994). This negative feedback mechanism has significantly fragmented sagebrush-dominated plant communities and led to a corresponding loss of biodiversity (Hemker 1997, Knick and Rotenberry 1997).

Land use conversion, especially from shrub-steppe communities to agriculture, has substantially changed the landscape composition of southern Idaho (Quigley and Arbelbide 1997). Thirty-six percent of the southern Idaho landscape has been developed for agriculture at the expense of shrub-steppe habitats.

1.2. Objectives

The goals of this study are to describe botanical resources, including rare plants and noxious weeds, in the vicinity of the transmission lines and to evaluate the impact of operation and maintenance activities on these resources. Our specific objectives are to

1) Identify and describe IPC service roads and transmission-line ROW associated with the HCC. 2) Identify and describe IPC operational and maintenance activities occurring within these ROW. 3) Identify specific issues related to IPC operations and maintenance that influence botanical resources. 4) Inventory general botanical resources, rare plants, and noxious weed species in the study area and evaluate the parameters that may influence the occurrence of these resources. 5) Record the types of disturbance activities and the intensity of each disturbance type in the ROW and along associated service roads. 6) Evaluate influences of IPC operations and maintenance on general botanical resources, rare plants, and noxious weeds. 7) Recommend appropriate protection, mitigation, or enhancement measures that minimize IPC’s impacts to botanical resources.

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2. STUDY AREA

2.1. Location

The HCC (also known as Hells Canyon Hydroelectric Project, FERC Project No. 1971) is located on the Snake River in the southern portion of Hells Canyon. IPC operates and maintains ROW on about 1,061 km (659 mi) of 14 transmission lines associated with the complex (Table 1). These ROW extend from southeastern Idaho west across the Snake River Plain and northwest to Enterprise, Oregon (Figure 1). Important population centers located near the transmission lines include Pocatello and Boise in Idaho and Baker City and Enterprise in Oregon.

The transmission-line study area was limited to public lands under the jurisdiction of state or federal authorities and to IPC-owned or managed lands. About 568 km (353 mi) of the transmission lines occur on public lands in Idaho and Oregon, and these are accessed by about 700 km of service roads.

A transmission-line corridor is a linear feature that buffers a transmission line. The width of the corridor may vary depending on the resources being evaluated. For most elements of this study, the corridor extended up to 5 km on either side of the transmission line. For the landscape region analyses, a variable-width corridor was used to capture vegetation patches intersecting both the ROW and parallel lines 1 km on either side of the ROW. Easements, grants, special-use permits, or FERC licenses may define ROW boundaries, and they define IPC’s rights within that area.

2.2. Climate

The study area is characterized by cool to cold, moist winters and hot, dry summers. The rain shadow effect of the Cascade Range blocks Pacific moisture and causes the semiarid climate of the region. The varied topography and geographic position of the study area further create variable climatic conditions. Typically, over 80% of the yearly precipitation falls between October and May (WRCC 1998).

In American Falls, located near Pocatello at the eastern edge of the study area, minimum and maximum temperatures for January average –9.2 °C (15.4 °F) and –0.3 °C (31.5 °F), respectively. July temperatures average a high of 30.5 °C (86.9 °F) and a low of 12.5 °C (54.5 °F). The average annual precipitation is 310 mm (12.2 in). Summer thunderstorms are common because of the continental climate influence.

Boise temperatures average a high of 2.4 °C (36.4 °F) and a low of –5.8 °C (21.6 °F) in January. Temperatures in July average a high of 32.3 °C (90.2 °F) and a low of 14.3 °C (57.7 °F). Annual precipitation averages 308 mm (12.1 inches). Boise receives an average of 541 mm (21.3 in) of snow, usually in small amounts that cover the ground for no more than a few days.

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At Brownlee Dam in Hells Canyon, July temperatures average a high of 34.7 °C (94.4 °F) and a low of 16.7 °C (62.0 °F). January temperatures average a high of 3.5 °C (38.3 °F) and a low of −4.6 °C (23.7 °F). The average yearly precipitation is 444.4 mm (17.51 inches).

The transmission lines reach their highest elevation at about 5,700 ft (1,750 m) on Summit Ridge along the Hells Canyon to Hurricane line (Line No. 910) west of Hells Canyon Dam. The Hells Canyon to Hurricane western line (Line No. 913) reaches a similar elevation on the high plateaus between the Imnaha River and Enterprise. These higher elevation areas are colder and wetter than the sites described above; however, weather data representing these sites are not available.

In the northwest portion of the study area, January temperatures in Enterprise average a high of 1.1 °C (33.9 °F) and a low of –10.1 °C (13.9 °F). Temperatures in July average a high of 28.3 °C (82.9 °F) and a low of 6.0 °C (42.8 °F). Annual precipitation averages 332 mm (13.08 inches).

2.3. Geology

The transmission-line study area encompasses six major geologic formations: the Snake River Plain, western Snake River Plain, Idaho Batholith, Columbia Plateau, and Wallowa and Seven Devils complexes (Alt and Hyndman 1989).

Most of the rocks along the floor of Hells Canyon belong to the Seven Devils complex. This complex consists mostly of tightly folded sedimentary and volcanic rocks. The more recent Columbia Plateau flood basalts line the higher canyon walls on both sides of the river.

The corridors heading west into Oregon pass through Columbia Plateau basalts in the valleys at lower elevations and cross the eastern margin of the Wallowa complex at higher elevations. Like the Seven Devils, the Wallowa complex is a mix of sedimentary and volcanic material. The Wallowa and Seven Devils complexes are part of a group of oceanic islands that docked into the North American plate about 100 million years ago.

Extending southeast from Hells Canyon to about Weiser, the transmission-line corridor passes through a mixture of Columbia Plateau basalts and sediments from ancient lakes that were impounded behind the lava flows. Further to the southeast, the geology of the corridor begins grading into the western Snake River Plain geology, a basin and range fault block that trends northwest from Twin Falls and that is distinct from the Snake River Plain. The western Snake River Plain fault block filled with white rhyolite ash, black basalt lava flows, and an assortment of valley-fill sediments as it dropped between faults.

The transmission-line corridor passes just north of Boise in the foothills of the Boise Front and intersects the edge of the Idaho Batholith. This large expanse of granitic mountains encompasses much of central Idaho.

East of Boise to American Falls, the transmission corridor reenters the western Snake River Plain before reaching the primary Snake River Plain near Mountain Home. The Snake River Plain consists of a thin mantle of basalt flows covering greater quantities of white rhyolite, which

Page 12 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line originated from volcanic activity in the plain. Interspersed in the plain are giant gravel bars and basalt boulder fields left behind when Lake Bonneville (the ancestral Great Salt Lake) flooded during the last ice age about 15,000 years ago. When the lake flooded, it strewed debris, created huge gravel bars, and carved new patterns in the landscape of the Snake River Plain.

2.4. Vegetation

Shrub-steppe and herbaceous grassland vegetation types dominate the transmission-line corridor, with each type accounting for about 40% of the area, or together, 80% of the area. Prominent herbaceous species include Pseudoroegneria spicatum (bluebunch wheatgrass), Festuca idahoensis (Idaho fescue), and Bromus tectorum (cheatgrass). Shrub species common to the area include various types of Artemisia species (sagebrush), Ericameria species or Chrysothamnus species (rabbitbrush), and Purshia tridentata (antelope bitterbrush). Coniferous forest composed of Pinus ponderosa (ponderosa pine), Pseudotsuga menziesii (Douglas-fir), and Abies grandis (grand fir) is primarily limited to the Wallowa Mountains in Oregon and encompasses about 5% of the study area. Agricultural land, occurring on about 10% of the study area, is concentrated along the eastern part of the Snake River Plain. About 1% of the area supports riparian or wetland vegetation types.

2.5. Jurisdiction

Forty-six percent of the 1,061 km (659 mi) of transmission lines included in the study area occur on private lands and are thus outside the scope of this study (Table 2). The other 54% (568 km) occur on public lands under the jurisdiction of either state or federal governments or on IPC-owned or managed land. Thirteen percent are on State of Idaho land, while none of the transmission lines are on Oregon state land. Of lines on federal lands, 70% are under the jurisdiction of the BLM, 14% are under the jurisdiction of the USFS, and less than 2% of the lines cross Bureau of Reclamation (BOR) land. Less than 1% crosses IPC-owned or managed land.

3. METHODS

The methods for this study are organized into five broad categories:1) cover type mapping; 2) surveys for rare plants, noxious weeds, and disturbance factors; 3) operation and maintenance (O&M) descriptions; and 4) analysis of the effects of O&M of the lines on botanical resources.

3.1. Cover Type Mapping

For all project lines, we created digital vegetation cover type maps for the ROW and for a 10-km wide corridor centered on the ROW. The corridor map was divided into seven landscape regions to facilitate analysis on a regional basis.

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3.1.1. Rights-of-Way

We created a ROW cover type map from a combination of sources and scales and included only public and IPC-owned or managed lands. Our objective was to use the most accurate source available for a given line or portion of a line.

In September 2000, we classified the majority of the project lines (903 through 907 [non-forested portion], 911, 912, and 951) from a helicopter. We recorded the locations of cover types as linear segments using a global positioning system (GPS). The cover type that best fit a homogenous segment of existing vegetation or nonvegetated cover within the ROW was assigned, though there may have been small inclusions of other cover types within a segment. Mapping units measured a linear distance of at least 100 m, except in riparian areas, which we mapped to 10 m when we saw them from the air. The cover type classification was based on the southern Idaho GAP land cover classes (Homer 1998). Southern Idaho data consisted of 101 land cover classes. All cover type classifications used in the study are detailed in Appendix 1.

For the mountainous regions of Oregon, we conducted ground surveys on portions of four lines (907, 908, 910, and 913) where vegetation clearing takes place within the ROW. The WWNF vegetation map does not capture the cleared ROW because its scale is not fine enough. We recorded the cover type at sites that had a vegetation pattern visually distinct from the area outside the ROW. We did not survey areas that are open savannah, where only a few individual trees had been removed. The ROW were treated as linear segments that were delineated into different Idaho GAP cover types recorded on a GPS. We selected the type that best fit a homogenous segment of vegetation within the ROW, realizing that there were small inclusions of other cover types within a segment. Minimum mapping distance was 10 m. Riparian areas were delineated if they represented unique vegetation types when compared with the adjacent cover type in the ROW, even if the areas were just narrow bands perpendicular to the ROW. The outstanding ROW portions of the four lines on the WWNF were cover-typed using the WWNF map, with the types being converted to Idaho GAP classes (see Appendix 1). We kept one WWNF cover type, Abies concolor (white fir), because there was no equivalent Idaho type. The WWNF map is based on analyses of field data (e.g., stand exams) and interpretations of aerial photos. The map consists of about 200 cover classes, 80 of which are within the study area. The scale of this vector data is 1:15,480, and the minimum mapping unit is 2.02 ha (5 acres).

Three non-forest area lines were not cover-typed during the helicopter flight. Line 945 runs adjacent to a paved road between Oxbow and Hells Canyon dams and has a small ROW width of 15 m (50 ft). Most of the line (92%) is within 15 m of the road. These portions were classified as low disturbance. The remainder of the line was cover-typed using vegetation data from IPC’s ground survey (Holmstead 2001) and from digital orthophoto quads; cover types were then reclassified to fit Idaho GAP types (Appendix 1). The IPC data were created using ground surveys and 1:15,000-scale aerial photos and have a minimum mapping unit of 0.004 ha (6 m x 6 m). Lines 923 and 952 are short lines (5–6 km) that are mostly on private land. They were cover-typed using the digital version of the Idaho GAP map.

We compiled the final cover type map by using the above resources, prioritized in the following order: 1) ground survey of cleared portions of forested region, 2) WWNF data, 3) helicopter typing, 4) IPC vegetation map, and 5) Idaho GAP. Analyses were performed to summarize the

Page 14 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line extent and distribution of cover types in the ROW. For each transmission line, and for all lines combined, we made several calculations for each cover type: linear extent in kilometers, aerial extent in hectares, and proportion of the total area.

3.1.2. Corridor

We created a cover type map with a 10-km-wide corridor centered on the ROW for all project lines. We used all lands for the corridor map regardless of ownership, even though our evaluation focused on public lands. On a landscape scale, it is important to consider land uses on private lands because these uses probably affect the condition of the botanical resources on public lands. We used existing digital data from three sources to characterize cover types outside the ROW: Idaho GAP, WWNF, and Oregon GAP. Idaho GAP and WWNF data were described above. The Oregon GAP digital data has 70 cover classes and is at a 1:100,000 scale with a minimum mapping unit of 100 ha (Kiilsgaard 1999). WWNF and Oregon GAP cover type classes were converted to the Idaho GAP classification. We then grouped some of the similar classes, which resulted in 40 possible cover types (Appendix 1). For analysis purposes, we clipped the data to within 5 km of the transmission lines. We used the spatial software programs   ARCINFO (ESRI 1992) and Arc View (ESRI 1992) to convert the WWNF polygon data and Oregon GAP data (1,000 m cell) to 30 m cell grids. We then combined all three sources with Idaho GAP data as a first priority, WWNF data as a second, and Oregon GAP data as a last priority (due to a large minimum mapping unit). We determined the number of cover type classes and the proportion of each cover type relative to the entire corridor. We performed further analyses on a landscape region basis.

3.1.3. Landscape Regions

We divided the corridor cover type map into seven landscape regions—four in Idaho and three in Oregon—to examine differences within the study area and to better compare ROW vegetation patterns with corridor vegetation patterns. Our intent was to evaluate landscape processes and impacts before trying to determine causative factors for vegetation composition and condition in the ROW. Reducing study area variation by regionalizing should improve identification of project-related effects. The landscape regions were based on the following criteria: 1) state boundaries, 2) cover type map sources, 3) vegetation communities based on coarse vegetation patterns (USFS 1996), and 4) topographic homogeneity.

We investigated the extent to which primary landscape processes likely influence vegetation in each region. These processes are land use conversion (urbanization, agriculture, logging, and grazing), wildfire, and invasion of exotic plants. We used the regional cover type maps to examine urbanization and agricultural influences. We assumed that logging influences occur only on those portions of the National Forests within the corridor open to logging. The Interior Basin Ecosystem Management Project (ICBEMP) (Quigley and Arbelbide 1997) provided data on grazing, wildfire, and exotic plant invasion. Quigley and Arbelbide (1997) examined the status and trends of landscape processes and functions within the Columbia River basin. The transmission line corridor is within the basin and passes through four of the ecological reporting units of the basin study. We also examined wildfire data from geographic

Hells Canyon Complex Page 15 Effects of Road and Transmission Line Idaho Power Company information system (GIS) layers collected for a sage grouse evaluation study (SAIC and Spatial Dynamics 2001).

3.2. Surveys along Rights-of-Way and Service Roads

Between March and September of 1999 and 2000, IPC conducted rare plant and noxious weed surveys on service roads, tower sites, and ROW clearing areas that occur on public lands along all transmission lines associated with the HCC. Service roads are distinguished from access roads. The primary purpose of service roads is to provide maintenance crews access to the transmission lines. These roads would probably not occur if the transmission lines did not exist. In contrast, access roads generally serve a broader purpose, such as contributing to the USFS, county, or state road systems. Access roads provide direct or indirect access to the transmission lines, but that is not their primary purpose.

A total of 692 km (430 mi) of service roads lie on public land. Of these units, 468 km (291 mi, or 68%) were surveyed. Another 175 km (109 mi) were not directly surveyed but were considered a subsample of the areas surveyed (Table 3). Subsampling occurred where vegetation composition and physiognomy were similar over large portions of the landscape. In such cases, we surveyed service roads along 1-mi segments that were randomly selected from every 5 mi of transmission line; these surveys resulted in a 20% subsample. During the survey period, we missed 49 km of service roads on public land that were not known to exist, but IPC personnel have since located those sections.

In all, 785 survey units, each consisting of cleared ROW areas, tower sites, short service road segments, and/or service road segments extending from a tower location to an access road, were delineated. We mapped survey units electronically by using a GPS and manually by writing on field copies of U.S. Geological Survey (USGS) topographic quadrangle maps. The survey units for HCC transmission lines are delineated in Appendix 2.

For each survey unit, botanists recorded all rare plants and noxious weed species present. Relative abundance of each species was recorded for the following three zones: 1) on the immediate roadbed or tower pad location, 2) within 50 m of the roadbed or pad location, and 3) in the area farther than 50 m from the roadbed or pad location. Definitions of abundance ratings are presented in Appendix 3. The types of disturbance present in each survey unit and the intensity of each disturbance type were recorded, as were general observations regarding disturbance, wildlife, rare plant or noxious weed occurrences, effects of transmission operations, and trend and condition of survey unit areas. A sample survey form with complete instructions is provided in Appendix 4.

Survey data were entered into a Microsoft Access database. GPS files of survey units and rare plant locations were imported into ArcView®. Survey units and rare plant locations without GPS data were digitized into ArcView® from field maps. In ArcView®, all survey units were attributed with field data from the Access database. Survey methods are further outlined below, in sections 3.2.1 and 3.2.3.

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3.2.1. Rare Plants

3.2.1.1. Prefield Review Prior to field research, IPC, in consultation with the TRWG, developed lists of special status plant species to be considered during transmission-line surveys. Listed species were categorized as either search species (species upon which surveys should focus) or incidental species (species for which information should be collected if encountered incidentally). Twenty-seven search species and 43 incidental species were designated for Idaho, while 25 search species and 37 incidental species were designated for Oregon (Appendix 5).

Selection and Prioritization of Species In November 1997, IPC met with agency officials to establish and implement criteria for identifying and prioritizing rare plant species inventories for the Hells Canyon study area and associated transmission lines. Those participating in the Hells Canyon TRWG decided to select a subcommittee to choose the rare plant species. Participants in the TRWG included representatives from the Idaho Department of Fish and Game (IDFG), BLM, USFS, Oregon Department of Fish and Wildlife (ODFW), USFWS, Idaho Department of Environmental Quality (IDEQ), IPC, and a few nongovernmental organizations. The selected subcommittee consisted of representatives from the BLM Boise District, USFS WWNF, and IPC. These participants initially considered all plants listed on federal and state threatened and endangered (T&E) species lists. Previously compiled species lists for the Shoshone, Hagerman Valley, Swan Falls, and C.J. Strike relicensing studies were also used. Participants decided that search priority would be given to legally protected (i.e., federally listed) T&E species, federal candidate and proposed candidate species, species ranked by The Nature Conservancy as global priorities 1 and 2, species ranked by the Native Plant Society as Idaho state priority species, and species listed in Oregon as threatened and endangered. Lower ranking species in Idaho and Oregon were evaluated according to the likelihood that suitable species habitat existed in the study area and the likelihood of the species being impacted by IPC activities. The final list of rare plant species considered in this study was approved by the TRWG and is in Appendix 5. IPC personnel conducted a review of area flora manuals and available literature to obtain bibliographic data for species in question. In addition, personnel contacted agency botanists and other local experts and conducted specimen research at herbaria at the following universities: Boise State University, University of Idaho, Albertson College of Idaho, and Washington State University. Federal and state rare species ranks are defined in Appendix 6.

Known Rare Plant Occurrences IPC obtained electronic data of species locations, called Element Occurrence Records, from the Idaho Conservation Data Center (IDCDC 2001a) and the Oregon Natural Heritage Program (ORNHP 1998). These electronic records included locations and pertinent information on all reported occurrences of rare plant species in the study area. Idaho and Oregon coverages were imported into ArcView and converted to a single shape file. During both the planning and survey periods of this study, the IPC field crews accessed these data, in conjunction with USGS digital orthoquads and digital rastergraphs covering the study area.

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Rare Species Identification A field manual with photographs or technical illustrations and written descriptions of rare plants and their habitats was compiled and provided to field crews in preparation for rare species inventories. Field crews also attended three-day sessions on lichen identification, led by Roger Rosentreter of the BLM, and moss identification, led by Robin Jones of the U.S. Department of Agriculture, Agricultural Research Station. Several technical keys were used to identify plant species, including Hitchcock and Cronquist (1973), Cronquist et al. (1977, 1984, 1997), Hitchcock et al. (1977–1997), Welsh et al. (1987), DeBolt and Rosentreter (1988), Barneby (1989), DeBolt (1989), Hickman (1993), and Cronquist (1994).

3.2.1.2. Field Methods For each survey unit, IPC botanists thoroughly searched the immediate roadbed, tower pad, or cleared ROW and the area within 50 m of the roadbed or pad location (buffer zone) for rare plant species. The area beyond the buffer zone was scanned for suitable rare plant habitat. When such habitat was observed, botanists investigated the area for the presence of rare plants. For each rare species encountered, they recorded phenologic, demographic, and topographic characteristics on standard reporting forms used by the IDCDC for Idaho occurrences and by the ORNHP for Oregon occurrences (Appendix 7). Information was also recorded for associated plant species, adjacent cover types, possible habitat threats, and conservation strategies for protection. Because of the difficulties involved in determining actual plant population boundaries in the field, all stands of rare plants were recorded, mapped, and referred to as “occurrences” rather than populations. Rare plant occurrence locations were mapped on USGS topographic quadrangle maps and recorded into a GPS. Rare plants and respective habitats were photographed with ASA 200 color slide film and TMX ASA 100 print film.

3.2.2. Noxious Weeds

3.2.2.1. Prefield Review Prior to field research, IPC, in consultation with appropriate agencies, compiled lists of noxious weed species that would be surveyed for both Idaho and Oregon. All 35 species listed by the Idaho Department of Agriculture were selected for surveys in Idaho. Twenty-six of the 100 noxious weed species listed by the Oregon Department of Agriculture were selected for surveys in Oregon, based on county noxious weed lists provided by Weed Supervisors from Baker, Malheur, and Wallowa counties, the only Oregon counties in the Hells Canyon study area. Noxious weeds included in the surveys appear in Appendix 8.

Noxious Weed Identification During initial training sessions in the field, IPC botanists reviewed the majority of local noxious weed species with survey crews. Crews were equipped with the following weed guides: Callihan and Miller (1999), C. T. Roché and B. F. Roché (1999), and Whitson et al. (1999). Technical keys were also available to aid in identifying noxious weed species, including Hitchcock and Cronquist (1973), Cronquist et al. (1977, 1984, 1997), Hitchcock et al. (1977–1997), Hickman (1993), and Cronquist (1994).

Page 18 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line

3.2.2.2. Field Methods IPC conducted noxious weed surveys simultaneously with rare plant surveys. Because of the difficulties involved in determining actual plant population boundaries in the field, all stands of noxious weeds were recorded and referred to as “occurrences” rather than as populations. Within each survey unit, botanists recorded all noxious weed species present. Relative abundance (Appendix 3) of each species was recorded for the following three zones: 1) on the immediate roadbed or tower pad location, 2) within 50 m of the roadbed or pad location (buffer zone), and 3) in the area farther than 50 m from the roadbed or pad location. IPC botanists thoroughly searched the immediate roadbed or tower pad location and the buffer zone for noxious weed species. They scanned the area beyond the buffer zone for noxious weed occurrences.

3.2.3. Disturbance Activities

Greenberg et al. (1997) define disturbance as a deviation from the natural processes that cause resource releases in a given ecosystem. Disturbance factors associated with the HCC transmission-line service roads were qualitatively evaluated. The types of disturbance present and the intensity of each disturbance were recorded for each unit. Disturbance intensity was rated as slight, moderate, high, or extreme for 13 categories, as outlined in Appendix 9. Disturbance factors considered included agriculture, big game, corridor clearing, fire, industrial use, livestock grazing, logging, non-project roads, off-highway vehicles, residential use, road use, service road construction, and water erosion. We recognize that not all of these activities are necessarily a disturbance, but these factors supplement analyses of direct and indirect project impacts. In addition, they may prove useful in determining causative factors for vegetation community composition and spatial arrangement.

The road use disturbance factor was not an original element of the survey protocol, but, following consultation with the TRWG, IPC biologists added it to the survey after it was underway. For consistency purposes, especially for the later analysis, the survey units that were completed before addition of the road use disturbance factor were back-categorized based on correlations with other disturbance activity levels, field notes, and personal knowledge of the study area.

3.3. Operation and Maintenance Activities

We compiled detailed information on the type, extent, timing, and frequency of O&M activities for each transmission line from past work records and discussions with maintenance personnel. For each transmission line we collected the following information:

• The types of O&M activities that have occurred in the past or are expected to occur in the future • If applicable, the type of technique used for a treatment when more than one treatment is possible • The calendar year in which the activity last occurred • The seasonal window, or time of year, that the activity can take place

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• The number of project days spent doing the activity • The number of personnel crews and type of crew(s) doing the work • The next calendar year the activity is planned to occur • The equipment used to conduct the activity • For emergency maintenance activities, the predicted number of occurrences in a 10-year period (because emergency activities are not planned or scheduled and because they are dynamic by nature, many of the above parameters were not applicable) Precisely defining the spatial extent of O&M activities within the extent of a transmission line was not possible. Therefore, we assumed that O&M activities occur equally throughout the extent of a line and that future events requiring an O&M response would have an equal probability of occurring across the entire line.

3.4. Analysis of Transmission Line Effects on Vegetation

The evaluation of O&M-related impacts of transmission lines on vegetation consists of qualitative and quantitative procedures and varies from the landscape to the patch scale. We spatially analyzed for potential effects of the transmission-line ROW on landscape-level vegetation patterns within a large transmission-line corridor. We spatially evaluated potential impacts from O&M activities through impact-based indices in relation to general vegetation, rare plants, and noxious weeds. And finally, we quantitatively determined from survey results the amount and spatial location of vegetation clearing, including clearing of riparian vegetation, in the ROW.

3.4.1. Rights-of-Way Effects on Landscape Level Vegetation Patterns

To evaluate differences in vegetation patterns between the transmission line ROW and surrounding areas, we compared vegetation patches intersecting the ROW with patches intersecting similarly wide corridors 1 km away from either side of the ROW. We used the spatial software program ArcView (ESRI 1992). If habitat is fragmented due to the presence of a ROW, one would expect to see smaller vegetation patches and more patches associated with the ROW than with surrounding areas. We felt that 1 km was a sufficient distance from the ROW to eliminate any influence on vegetation due to the ROW. Each ROW is either 30.5 m or 45.7 m wide (100 or 150 ft), except for one ROW that is 15.2 m (50 ft) wide.

For each of the four Idaho landscape regions (Snake River Plain, Snake River Valley, Payette Valley, and Idaho Canyon/Mountain), we used the Idaho GAP vegetation coverage and grouped a few of the similar vegetation types as we did for the corridor map (Appendix 1). We then converted the raster-based corridor map to a polygon map. Finally, for each region we created three new coverages that included only those GAP vegetation patches (polygons) that intersected the ROW or intersected the comparison areas 1 km away from either side of the ROW. For the Idaho Canyon/Mountain region, we had only an eastern comparison area, as a western area would have extended beyond the coverage of our GAP cover map.

Page 20 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line

Of the four Idaho and three Oregon regions, the WWNF Region in Oregon is the one most likely to have different vegetation patterns in the ROW than in surrounding areas because of tree removal and shrub trimming. We used a different methodology to create the ROW-intersect map for this region because we wanted to use our map of actual ROW cover types (see section 3.1.1). We merged our grouped version of the WWNF vegetation map with the actual ROW cover type map. In order to keep the true ROW type, we clipped out WWNF areas that overlapped the ROW. We then examined WWNF cover type patches abutting the ROW and kept only those that were of the same type as in the ROW. When abutting cover types were not the same as those in the ROW, we removed them from the coverage. This removal resulted in an intersect map of the actual ROW cover types, with vegetation patches extending into the forest only when they were of the same cover types as the ROW. Adjacent comparison areas beginning 1 km out from either side of the ROW were intersected with just the grouped WWNF cover map.

We did not make intersect maps for the two other Oregon regions—Oregon Plateau and Canyon and Oregon Upper Plateau. The mapping scale of the Oregon GAP map is too coarse to detect any difference between ROW and comparison area vegetation patterns.

3.4.1.1. Spatial Composition Spatial composition of vegetation refers to the richness (number of cover type classes) and evenness (the proportion of each class) in relation to the entire area examined. To see if habitat patches making up the ROW-intersect were different from patches in the comparison areas, we determined the richness and evenness in all three. We used Patch Analyst 2.0 (Elkie et al. 1999), a program developed to quantify landscape structure and facilitate the analysis of patch patterns.

3.4.1.2. Spatial Configuration Spatial configuration of the vegetation refers to the physical distribution or spatial character of patches within the landscape (McGarigal and Marks 1995). In this study, a patch was a homogeneous polygon classified as one of the grouped cover types. Using Patch Analyst 2.0 (Elkie et al. 1999), we determined the number of patches, mean patch size, and patch size standard deviation for the ROW-intersect and comparison areas. These spatial configuration metrics were chosen based on the available data sources and ecological processes that may be affecting the vegetation of the landscape regions.

3.4.2. Operation and Maintenance Effects on Vegetation

To assess the influence of O&M activities on vegetation, we developed an O&M Activity Index and O&M Risk Index to represent two levels of potential O&M impacts for each transmission line. Both indices are derived from simple statistical models, not from on-the-ground assessments of impacts. Therefore, the indices are only meant to be indicators of potential impact or problem areas rather than indicators of areas of known or imminent impact.

Using information based on past and expected future O&M activities (see section 3.3), we rated the O&M activities by the level of impact they potentially could have on vegetation and soils. The values for these impact ratings ranged from 0 to 1.0, with 1.0 representing the highest level of potential impact. Four categories of impact were defined: no impact (0.1), minor impact (0.3),

Hells Canyon Complex Page 21 Effects of Road and Transmission Line Idaho Power Company major impact (0.6), and emergency impact (1.0). A no-impact activity disturbs no ground or vegetation (e.g., line patrol or inspection). The activity occurs infrequently and for a brief duration (fewer than four hours) and requires few people. A minor impact activity may temporarily impact vegetation (e.g., from minor trampling associated with routine line maintenance), result in removal or trimming of individual plants (e.g., hazard trees), or involve routine maintenance of the roadbed. Such activity occurs infrequently for a brief to moderate duration (less than one day) or requires few people (fewer than 5). A major impact activity removes vegetation ground cover, modifies the physiognomy of plant communities in or adjacent to the ROW, severely tramples vegetation, extensively compacts soil, or disturbs ground off-road. Typically, personnel are present for a longer duration (more than 1 day) and the activity requires more people (5 or more) than for activities having no or minor impact. Emergency impacts are those resulting from emergency activities. Though such activities are unpredictable, they can severely impact vegetation or soil resources, depending on the circumstances and the treatment required.

To assess the scope of O&M activities on each line, and, therefore, the potential for impacts to occur to vegetation, we calculated an O&M Activity Index (Figure 2a). This index is a function of the impact rating described above and of the activity attributes, including the expected number of occurrences in a 10-year period, number of people, and number of days spent on the activity. We summed the product of this function for all activities occurring on a line and then divided by the line length to spatially standardize the index.

In addition to potentially having direct impacts, O&M activities require service roads for accessing the transmission-line ROW and facilities. Roads and the use of the roads can have an additional impact, depending on the road condition and level of use, among other attributes. To capture this potential, we developed an O&M Risk Index (Figure 2b), which is a function of the O&M Activity Index and road-related parameters—road use and road-related water erosion (see section 3.2.3). To calculate the O&M Risk Index (and to be consistent with the road condition and use classes), the O&M Activity Index was categorized into four classes: low (1), moderately low (2), moderate (3), and highest (4). The road use parameter was not initially collected as part of the survey protocol (see section 3.2.3); therefore, to have consistent data, we back-categorized the road segments that were not evaluated in the field. To do this, we developed a set of rules based on factors such as positive correlations with other road-related parameters, field notes, and direct knowledge of the area.

Each service road segment was spatially attributed with the O&M Risk Index. We categorized Risk Index levels of less than 1.0 as having low disturbance potential, from 1.0 to 1.5 as having moderately low disturbance potential, from 1.6 to 2.0 as moderate, and greater than 2.0 as highest. Road segments with an O&M Risk Index category of 3 or 4 were spatially overlaid with rare plant and noxious weed location data to assess potential impacts.

3.4.3. Rights-of-Way Clearance Studies

We conducted three studies to assess the extent and effects of removing hazard trees and trimming trees and shrubs within and adjacent to the ROW. Two studies focused on the forested regions of the ROW because the majority of the clearing occurs in these regions. The third study examined public land riparian areas potentially affected by O&M activities.

Page 22 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line

3.4.3.1. Forest Region Cleared Rights-of-Way Areas Four transmission lines (907, 908, 910, and 913) cross about 50 km of forested habitat on the WWNF. In July 1999, we conducted ground surveys along the ROW where there was an indication of vegetation clearing—where the ROW vegetation had a different pattern or physiognomy from the adjacent area. Our intent was to determine where habitats have changed due to the ROW. We mapped the cleared ROW with GPS linear segments and classified the existing vegetation, and resultant linear segment, using a GAP cover type. Minimum mapping distance was 10 m. We delineated all riparian areas within the surveyed segments, even when they extended outside the ROW. We did not record areas of open savannah where only a few individual trees had been removed. We used these data in creating the ROW cover type map discussed in section 3.1.1 and for the riparian map discussed in section 3.3.3.

We calculated the segment lengths by cover type and calculated total lengths of ROW that were different from adjacent areas. We also examined the difference between areas with and without forest adjacent to them. The areas with forest adjacent were assumed to be different because they undergo periodic clearing or trimming, whereas the areas with non-tree types adjacent were assumed different because of natural variation in the landscape.

3.4.3.2. Snag, Large Tree, and Log Characteristics Adjacent to Rights-of-Way Snags and large trees are a limited forest resource important to many wildlife species and to the ecosystem in general. Logs are typically less limited but still a valuable component of the forest ecosystem. National Forest plans must detail retention guidelines for snags and large trees (Bate et al. 1999). In the forested environments of the WWNF, IPC periodically clears woody vegetation in the 30-m-wide ROW to maintain the safety and reliability of the transmission-line system. Therefore, snags and large trees are not present in the ROW. On either side of this cleared corridor, there is an additional zone about 30 m wide (hazard zone) where IPC fells trees that pose a threat to the transmission lines because of their height, condition, and lean angle. When this zone is within the Hells Canyon National Recreation Area (HCNRA) of the WWNF, IPC cuts, but does not remove, trees or snags.

We conducted a pilot study to compare densities of snags, large trees, and logs that are immediately adjacent to the ROW with densities in forest areas outside of IPC’s zone of influence. The study area included Transmission Lines 907, 910, and 913 where they occur on the WWNF. These lines either start or end at Pallette Junction on the Imnaha River. Sampled sections of Lines 907 and 910 were within the HCNRA, whereas Line 913 sampled areas were outside the HCNRA. We sampled, within a series of transect plots, all snags with greater than 25 cm diameter at breast height (dbh), trees with greater than 50 cm dbh, and logs with a large-end diameter of 15 cm or more.

The pilot study consisted of 20 transects for both hazard zone and control sites. Methodology followed Bate et al. (1999) for snags and large trees and Bull et al. (1997) for logs. The purpose of the pilot study was to reveal the optimal transect size and to indicate whether 20 transects per stratum would be adequate to describe snag, large tree, and log characteristics in the area. Each transect was located by randomly picking a tower site, ROW side, and distance between the chosen tower and the next tower (0 to 40 m in 5-m increments). From this randomly chosen point, the starting point for the hazard zone transect was established perpendicular to the ROW,

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15 m beyond the edge of the ROW (Figure 3). The transect paralleled the ROW. The control transect paralleled the hazard zone transect; its starting point was 50 m from and perpendicular to the hazard zone starting point.

Transects were established by using a hip-chain starting from the point selected and extending it parallel to the ROW for 100 m. If the transect site was not continuous forest cover, the next randomly picked tower site was selected. Each transect consisted of two 50-m subsegments, which were delineated along the line with flagging. We assigned unique numeric identifiers to each subsegment. For each subsegment, we conducted a complete count of all qualifying logs intercepting the transect centerline and all qualifying snags or trees out to 15 m from the centerline. We also recorded the perpendicular distance from the centerline to the midpoint of each snag or tree. Snag and tree information recorded included the species, height, distance from centerline, dbh, condition or structural class, and foraging and cavity use (snags). Log data included the species, length, class (natural or cut and stump or down-log), structural condition, large- and small-end diameters, whether hollow, and sign of wildlife use.

We estimated snag, large tree, and log densities for both hazard zone and control transects. These estimates allowed us to compare the two transect types and assess the impact that hazard zones associated with transmission-line ROW may be having on these resources.

3.4.3.3. Riparian Characteristics in Rights-of-Way In the western , riparian ecosystems comprise a very small portion (approximately 0.5%) of the landscape (Ohmart and Anderson 1996), and yet they are used more than any other habitat by wildlife (Thomas 1979). Riparian refers to any vegetation on or near the bank of a watercourse. Conserving blocks of interconnected riparian ecosystems and their ecological functions is critical to biodiversity conservation in the (Hawkins 1994, Noss 1983, Noss et al. 1995). In fact, conservation of riparian ecosystems can be more advantageous than conservation of individual species for protecting biodiversity. In the transmission line ROW, riparian habitats have the potential to be reduced or degraded by IPC’s O&M activities, livestock grazing, recreational use, and land use conversions.

Our approach to describing existing riparian resources and assessing the effects of the O&M of transmission lines on riparian areas in the ROW was threefold. Because the ROW cover type map was created largely from methods too coarse to pick up small segments of riparian vegetation, we first refined this cover type map (described in section 3.1.1) for riparian locations by using other data sources to more accurately represent the riparian area present. In ROW sections that were cover-typed by helicopter or Idaho GAP, we examined digital orthophoto quadrangles, the IPC vegetation map, and field data recorded along service roads and then adjusted the cover type map accordingly. Second, we consulted with IPC’s vegetation management supervisor and digitally mapped all riparian areas that require trimming or removal. We collected data on species trimmed, clearing distance to line requirements, and frequency of maintenance. Data precision was variable. In some cases, discreet locations were identified, whereas in a few cases data was more coarsely mapped to include an entire tower span. We added these areas to the riparian ROW cover type map. Third, we made an assesment of the influence of the project lines on vegetation at Imnaha River line crossings. All bank edges where

Page 24 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line vegetation is removed or trimmed for line maintenance was digitized using a GPS. Data attributes include plant species affected and polygon size.

4. RESULTS / DISCUSSION

4.1. Cover Type Mapping

4.1.1. Rights-of-Way

Thirteen HCC transmission lines traverse 568 km (353 mi) of public or IPC lands, passing through 24 cover types (Table 4). Vegetation in the ROW were mapped using Idaho GAP cover types from a combination of helicopter survey, ground survey, and GAP cover type maps (see section 3.1.1. for details). Line 952 was not included because it is entirely on privately owned agricultural land. The vegetation in the ROW is predominately shrubland and grassland, which is present for 514 km (319 mi, or 91%). Disturbed areas, predominately roads, occupy 32 km (20 mi, or 6%) of the ROW. Forest, riparian, water, and barren land types each contribute less than 10 km (6.2 mi, or 2%) to the ROW.

In the eastern end of the study area, Lines 906, 912, and 951 cross the Snake River Plain from American Falls to Boise (Figure 4, panels 1 and 2). Elevations along these lines start at 1,370 m (4,500 ft) on the east end of Line 951 and gradually drop to 860 m (2,830 ft) at the Boise Bench Substation. Most of the route is in the 1,000- to 1,200-m range. These three lines are the longest in the HCC, totaling 295 km (183 mi), or 52% of all the lines. Their ROW are dominated by the big sagebrush cover type (19–53%), perennial grassland (9–46%), and annual grassland (17−34%) (Table 5). The Idaho GAP defines the big sagebrush cover type as shrubland principally dominated or codominated by Artemisia tridentata (basin big sagebrush) and Artemisia tridentata wyomingenisis (Wyoming big sagebrush). Perennial grassland is typified by common seeded grass species such as Agropyron cristatum (crested wheatgrass), Festuca idahoensis (Idaho fescue), Poa (bluegrass) species, and Stipa (needlegrass) species. Annual grassland is dominated or codominated by Bromus tectorum, Taeniatherum asperum (medusahead), and forbs including Lepidium perfoliatum (clasping pepperweed), Salsola kali (Russian thistle), and Sisymbrium altissimum (tumble mustard). Lines 951 and 912 pass through 10.3 and 21.7 km, respectively, of herbaceous burned area. Line 906 has 3.7 km of herbaceous burned area. These areas burned in 2000 just prior to the helicopter survey. Other than 1 km of ROW on Line 903, these are the only areas of recently burned vegetation in the ROW. The three lines cross small areas of rabbitbrush (3.2 km), salt-desert shrub (0.5 km), wet meadow (0.6 km), and barren land (1.1 km) (Table 4). Barren land is typically mud flats, river sand bars, or bare soil. These lines pass over only 400 m of water combined. The major crossings are near Gooding where Lines 912 and 906 cross the Big Wood River and Line 912 crosses the Little Wood River.

Line 923, at the very eastern end of the study area, traverses only 0.4 km of public (State of Idaho) land (Figure 4, panel 1). This line crosses the Snake River just below the American Falls

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Reservoir and passes through sagebrush, riverine riparian, and barren land. The Idaho GAP defines riverine riparian as a mixed riparian class dominated by conifer species and shrubs. Primary associated tree species are elevation dependent and can include Abies lasiocarpa (subalpine fir), Acer glabrum (Rocky Mountain maple), Picea engelmanni (Engelmann spruce), Pinus contorta (lodgepole pine), Pseudotsuga menziesii (Douglas-fir), and Populus (cottonwood) species. Primary associated shrubs include Amerlanchier (serviceberry) species, Prunus virginiana (chokecherry), Ribes (currant) species, and Salix (willow) species. Although these species define the riverine riparian cover type, Populus and other deciduous species are dominant along this section of line where it is associated with the Snake River.

In the central portion of the study area, Lines 904 and 911 extend 164 km (102 mi) from Boise to Brownlee Dam, passing through foothill and mid-elevation habitats (Figure 4, panel 3). Elevations rise from 860 m (2,830 ft) at the Boise Substation to 1,390 m (4,560 ft) at the Cuddy Mountains west of Cambridge and then drop down to 540 m (1,760 ft) at Brownlee Substation near the dam. The lines rise and fall in elevation as they go through several valleys where they cross the Boise, Payette, and Weiser rivers and numerous small creeks. Public land is present on 64 to 68 km of each line. Perennial and annual grasslands are the most common cover types in the ROW, representing 62 to 66% (Table 5). The big sagebrush cover type is less common than on the eastern lines, contributing to only 12 to 15% of the ROW. The bitterbrush, montane shrub, and low sagebrush cover types combined represent 18 to 21% of the ROW. The bitterbrush cover type is dominated by Purshia tridentata (antelope bitterbrush). The low sagebrush cover type is dominated by Artemisia arbuscula (low sagebrush). Montane shrub is typically dominated or codominated by Alnus (alder) species, Amerlanchier species, Berberis repens (Oregon grape), Ceanothus (snowbrush) species, Physocarpus malvaceus (mallow ninebark), Prunus virginiana, Ribes species, Salix scoulerian (scouler willow), and Symphoricarpos (snowberry) species. Line 911 has four segments of riverine riparian (totaling 1.2 km) and four segments of shrub riparian (1.3 km). The shrub riparian cover type is typically dominated by Salix species and may include Acer negundo (box elder maple), Alnus species, Artemisia cana (silver sage), Betula (birch) species, Prunus virginiana, and Potentilla fruticosa (cinquefoil). Remaining portions of the ROW for these two lines have 1.1 km of Douglas- fir/ponderosa pine in small forest pockets between Cambridge and Brownlee Dam.

At the western extent of the study area, Line 903 extends from Brownlee Substation near the dam to Baker City, Oregon, and 33 km (20.5 mi) of its 74 km (46 mi) pass through public land (Figure 4, panel 4). Elevations rise from 540 m (1,760 ft) to 1,070 m (3,500 ft) in Baker City. The line crosses through the Powder River Valley for about 25 km. Big sagebrush (14.6 km) and perennial (10.8 km) and annual grasslands (5.5 km) dominate these areas. Herbaceous burn (1 km), bitterbrush (0.2 km), low sage (0.4 km), and water (0.1 km) make up the remainder of the ROW (Table 4).

Lines 905 and 945 are entirely within Hells Canyon. Line 905 runs along the eastern shore of Oxbow Reservoir from Brownlee Dam to Oxbow Dam. Line 945 runs along the eastern shore of Hells Canyon Reservoir from Oxbow Dam to Hells Canyon Dam. Line elevation declines gradually from 540 m to 515 m (1,690 ft) at Hells Canyon Dam. The 13 km (8.1 mi) of public land ROW on Line 905 is 44% perennial grass, 27% annual grass, and 23% bitterbrush. Shrub riparian is present along about 200 m of the ROW. In contrast, Line 945 runs adjacent to a paved

Page 26 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line road and is classified as 93% (31 km) disturbed habitat. There are minor amounts (< 1 km) of big sagebrush, perennial grassland, and rock present (Table 5).

Line 907 extends downstream from Oxbow Dam along the west side of Hells Canyon Reservoir for about half its length before climbing into the forested WWNF and ending at Pallette Junction on the Imnaha River (Figure 4, panel 4). The line rises in elevation from 527 m (1,730 ft) to 1,660 m (5,450 ft) where it enters the HCNRA on the WWNF and then declines to 1,100 m (3,600 ft) along the Imnaha River. This line passes through 12 Idaho GAP cover types, more cover types than any of the other project lines. The canyon portion of the line is largely in bitterbrush (6.5 km) and perennial grassland (6.2 km) (Table 4). As it passes up into higher elevations, the line crosses through montane shrub (6.2 km), alpine shrub (0.7 km), and dry (2.1 km) and wet meadows (0.4 km). The alpine shrub cover type consists of shrubland principally dominated by Salix species or Vaccinium (blueberry) species. Potentilla fruticosa, Ribes species, and Symphoricarpos species may also be present. Three kilometers of the ROW have remained forested due to spans across valleys, spans that allow for tall trees without interference to the lines. There are 1.7 km of Douglas-fir, 0.8 km of ponderosa pine, and 0.5 km of grand fir cover types. Line 907 crosses and runs parallel to the Imnaha River for about 7 km. This area has 24 segments of riverine riparian totaling 2.7 km. The riparian habitat in this area is discussed in detail in section 4.3.3.

The three remaining project lines—908, 910, and 913—radiate out from Pallette Junction at the Imnaha River. Lines 908 and 910 are completely in the HCNRA. Line 913 is in it for only 2 km. Line 908 continues north 15 km along the river to the town of Imnaha through mostly private land, dropping gradually to an elevation of 600 m (1,965 ft). The majority (66% or 3.9 km) of public land portions of Line 908 is perennial grassland. The remaining portions include 0.9 km of Douglas-fir, 0.8 km of montane shrub, and 0.3 km of riverine riparian cover types. Line 910 heads east 13 km to drop to the Hells Canyon Dam. The Hells Canyon Wilderness Area surrounds the line for the last 5 km. This ROW is dominated by perennial grassland (44%) and montane shrub (35%). Less common cover types are Douglas-fir, white fir, and rock. Line 913 heads west to Enterprise for 47 km, of which 14 km is on public land. The line rises from the Imnaha River to 1,730 m (5,670 ft) and then gradually declines to 1,190 m (3,900 ft). ROW composition is similar to that of Lines 908 and 910, with a mixture of perennial grassland, alpine and montane shrub, Douglas-fir, and dry meadow cover types. This line is the only in the HCC that shows the cover type of herbaceous riparian (0.1 km), which consists of various Carex (sedge), Juncas (rush), and forb species.

4.1.2. Corridor

The cover type maps for the 10-km-wide transmission-line corridor includes 1,061 km (659 mi) of line, encompasses 880,732 ha (2,176,327 acres), and includes both public and private lands (Figure 1). Seventy Idaho GAP cover types, represented by 32 grouped cover types, are present in the corridor. Big sagebrush and perennial grassland dominate the landscape, each making up about 26% of the corridor (Table 6). Species components of these cover types were detailed in the previous section (4.1.1). Agricultural areas are the third most common vegetation type, occupying 15% of the corridor in primarily the eastern portion. A thorough discussion of cover type distribution throughout the corridor is presented in the next section (4.1.3). Bitterbrush

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(6.8% of the corridor), dry forest (6%), annual grassland (5.1%), low sagebrush (3.2%), and wet forest (2%) account for most of the remaining corridor area. The dry forest cover type consists of Pinus ponderosa and Pseudotsuga menziesii, with Abies grandis as a subdominant species. The wet forest group is made up of Abies lasiocarpa, Abies grandis, Picea engelmanni, Pinus albicaulis (whitebark pine), Pinus flexilis (limberpine), and Abies concolor. Typical subdominant species are Pseudotsuga menziesii and Pinus contorta.

Less common cover types representing 1 to 1.8% (8,655 to 15,680 ha) of the corridor include rabbitbrush, montane shrub, riparian, burned herbaceous, water, and perennial grass montane. The riparian cover type is a grouped class including riverine, deciduous tree, shrub, and herbaceous riparian cover types. The species components of these cover types were detailed in the previous section (section 4.1.1). Nine additional cover types contribute to 0.1 to 0.7% of the corridor (Table 6). Of these, the wetland type is the only grouped cover type; it consists of the Idaho GAP types deep marsh, shallow marsh, mud flat, and aquatic bed. Nine cover types are present over less than 0.1% (400 ha) of the corridor and five are not shown in Table 6. They include the juniper, alpine shrub, tall forb montane, barren, and low disturbed cover types.

4.1.3. Landscape Regions

The 10-km-wide transmission line corridor was divided into seven regions based on 1) state boundaries, 2) cover type map sources (Oregon and Idaho GAP and WWNF), 3) vegetation communities (USFS 1996), and 4) topographic homogeneity. Figures 5 to 8 show the distribution of cover types that are present in more than 0.1% of each region. Less common cover types are not visible on a map of this scale.

4.1.3.1. Snake River Plain The transmission-line corridor within the Snake River Plain region contains 241,519 ha (596,804 acres) and is about 190 km (118 mi) long in the easternmost portion of the study area (Figure 5). The region is bounded on the east by American Falls Reservoir and on the west by Pioneer Reservoir, near King Hill. Transmission Lines 923, 951, 952, and portions of 906 and 912 occur within the region and total about 250 km (155 mi). Although 20 of the 32 corridor cover types are present in the region, three dominate 90% of it. Agriculture covers 36.6%, perennial grassland covers 26.8%, and big sagebrush covers 26.1% (Table 6). About 43% of the region is privately owned, accounting for the high amount of agriculture. In fact, this region contributes to 67% of all agriculture present over the seven landscape regions. Perennial grassland is scattered throughout the region but occurs in large continuous tracts on the western half. Big sagebrush is also scattered throughout the region but exists in larger continuous tracts in the eastern one-third of the region, between Minidoka and American Falls and in areas around Gooding. Some of the more minor cover types include annual grassland (1.3% of the region), low sagebrush (2.3%), and rabbitbrush (2.4%). The latter two are intermingled with the sagebrush. Large lava fields, which occur only in this region, are east of Minidoka and east of Gooding. Urban areas are present within the region at American Falls, Rupert, Minidoka, and Bliss and on the outskirts of Gooding. The water cover type (1.9% of the region) is primarily made up of Lake Walcott, the Snake River, the Big Wood River, and a very small portion of American Falls Reservoir.

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The major landscape processes exerting an influence on vegetation in this region include agricultural development, livestock grazing, exotic plant invasion, and wildfires. As mentioned above, this region is almost 37% agriculture. Livestock grazing occurs throughout the corridor on all public land and on some private lands. Quigley and Arbelbide (1997) summarized broad- scale landscape conditions in each ecological reporting unit (ERU) of the Columbia River basin, focusing on historical to current changes in vegetation and disturbances. The Plain region is equally divided between the Owyhee Uplands ERU and the Upper Snake ERU. In general, the non-forested landscapes of both ERUs have been extensively fragmented, and excessive livestock grazing pressure has degraded many riparian areas. Invasion and dominance by exotic annual grasses have shortened the fire-return interval and caused a decline in abundance of native flora. The risk of intense fires on BLM and USFS lands was rated as moderate for the ERUs based on fires in the 1980s. ICBEMP data show 12 very small and 2 large fires near the transmission lines between 1986 and 1992. BLM fire data layers also show that very few fires occurred in the region between 1950 and 2000. In the Upper Snake ERU, a large proportion of the native shrublands has been extensively fragmented, largely by agricultural developments, and a large portion is highly susceptible to invasion by Bromus tectorum. The cover type map for the 10-km corridor shows the region to have only 1.3% annual grass cover, but the actual figure is probably much higher. On a satellite image, annual grass is very hard to distinguish from other grassland types. The accuracy of the Idaho land cover map is estimated at 68% (Homer 1998). When we compared the Idaho land cover map with the actual extent of annual grass within the ROW (known from our field study), we found 88% to be incorrectly typed. Therefore, our regional cover type map underestimates the extent of exotic annual grasses in the region.

Urbanization has contributed to minor changes within the region. Four cover types indicate extent of land development: high and low density urban and high and low disturbed. The high density urban type includes towns with populations greater than 1,000. The disturbed types include mines, airports, landing strips, golf courses, and parks and other recreation areas that are separate from urban areas. This region is 0.5% developed.

4.1.3.2. Snake River Plateau Just west of the Snake River Plain region is the 110-km (68.4 mi)-long Snake River Plateau region (Figure 6). This 152,774-ha (377,511-acre) region extends from Pioneer Reservoir on the east to just southeast of Boise. Transmission Lines 906 and 912 occur within the region for a total of about 215 km (134 mi). Compared with the Snake River Plain region, this area is characterized by higher elevations, much less agriculture, and a high interspersion of shrubland and grassland types. Twenty-one of the 32 corridor cover types are present in the region, with two dominating. Big sagebrush covers 40% of the region, while perennial grassland covers 24.3% (Table 6). Four other common shrubland types make up15.6% of the region. Bitterbrush occurs at the higher elevations in the center of the region. Rabbitbrush occurs at the lower elevations, in large continuous blocks near the eastern edge. Salt desert shrub also occurs at the lower elevations, scattered throughout the area. And low sage is concentrated on the eastern portion of the region upslope of the rabbitbrush. Annual grassland is probably under-represented by the cover type map (4.5%). The high extent of burned area makes this region different from the others. Large grass and shrub fires occurred over 8.2% of the area, probably in 1992. Agriculture (5.6%) is concentrated in the eastern, low-elevation areas. About 32% of the region is privately owned, and much of this is probably rangeland. This region has no large urban areas

Hells Canyon Complex Page 29 Effects of Road and Transmission Line Idaho Power Company or land development. There is less than 0.1% of low-density urban type at King Hill and Mayfield. Figure 6 shows several drainages with riparian habitat. Major patches of riparian habitat are present around Indian Creek Reservoir, around Mountain Home Reservoir, and in Canyon Creek. Undoubtedly, more riparian cover type is present in this and other regions, but cannot be detected at the coarse mapping scale.

As in the Snake River Plain region, the major landscape-changing processes occurring in the Plateau region include agricultural development, livestock grazing, exotic plant invasion, and wildfires. Livestock grazing occurs throughout the corridor on public and private lands. The Plateau region is in the Owyhee Uplands ERU, where there has been extensive habitat fragmentation and excessive livestock grazing pressure (Quigley and Arbelbide 1997). Invasion and dominance by exotic annual grasses, particularly within the big sagebrush cover type, has shortened the fire-return interval and caused a decline in abundance of native flora. The risk of intense fires on BLM and USFS lands was rated as moderate for the ERU based on fires in the 1980s. ICBEMP data show three large fires and several small fires near the transmission lines between 1986 and 1992. BLM fire data layers also show that many fires occurred in the region between 1980 and 1992. Areas that show as herbaceous and shrub burn on the regional cover type map appear to have burned in the early to mid-1980s and in 1992. Quigley and Arbelbide (1997) rated the line corridor as highly susceptible to invasion by Bromus tectorum. Our cover type map shows the region to have only 4.5% annual grass. Because of past fires and because our ROW maps show over 55 km of annual grass in the region, the actual percentage of annual grass in the region is probably much higher than 4.5%.

4.1.3.3. Payette Valley In the center of the study area, the Payette Valley region is about 140 km (87 mi) long (Figure 7). The 238,530-ha (589,418-acre) region is bounded on the east by Boise and on the west by the Cuddy Mountains west of Cambridge. The region can be broadly characterized as having a plains landform in the eastern and southern portion and foothills and mountain landforms in the northern and western portions. Transmission Lines 904 and 911 occur within the region and total about 280 km (174 mi). The region is diverse, having 22 of the 32 corridor cover types. Big sagebrush plays a smaller role in the shrubland component of this region than it does in the two Snake River regions, as big sagebrush is replaced by bitterbrush, low sagebrush, and to a smaller degree, montane shrub and mountain big sage. The three dominant cover types are perennial grassland (30.3%), bitterbrush (19.5%), and big sagebrush (17.2%) (Table 6). The shrubland is found throughout the region but in much larger continuous tracts in the western half. Grasslands are found to a greater degree in the eastern half. About 64% of the region is privately owned. Most of this private land is in shrub, grassland, and agriculture (6.6% of the region) types and is evenly distributed throughout the area. Some of the minor non-shrub cover types include annual grassland, dry forest, and riparian. As with the other regions, the extent of annual grassland is probably underestimated. The riparian cover type is distributed across the region in the numerous drainages. Large tracts of riparian type exist along Crane Creek, Big Willow Creek, the Boise River, Dry Creek, and Paddock Valley Reservoir. The water cover type (0.5% of the region) is primarily made up of Crane Creek Reservoir, Paddock Valley Reservoir, and the Weiser, Payette, and Boise rivers. This region has the greatest percentage of urban cover type (2.4%). Boise is the only high-density urban area in the region. Midvale, Cambridge, and the eastern edge of Emmett are the low-density urban areas.

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The Owyhee Uplands ERU covers the southern half of the region, and the Central Idaho Mountains ERU covers the northern half. The broad-scale landscape processes and disturbances occurring in the Owyhee Uplands ERU are described in the previous descriptions of the Snake River Plain and Snake River Plateau regions. The Central Idaho Mountains ERU is very large and mostly heavily forested. The portion of this ERU where the line corridor passes is not representative of most of the processes occurring in the ERU. However, the findings from Quigley and Arbelbide (1997) that may be applicable include degradation of riparian and south- facing upland areas due to excessive livestock grazing. As with all the corridor regions, livestock grazing occurs on public and private lands. At the transmission lines in this region, fire has played a large role in the landscape. BLM fire data layers show much of the southern two-thirds of the lines to have burned between 1986 and 1996. Quigley and Arbelbide (1997) rated the risk of intense fires on BLM and USFS lands as high to moderate and susceptibility to Bromus tectorum invasion as a mixed moderate and high. Our cover type map shows the region to have only 5.8% annual grass. Because of past fires and because our ROW map shows over 55 km of annual grass in the ROW, the actual percentage of annual grass in the region is probably much higher than 5.8%.

4.1.3.4. Idaho Canyon/Mountain The Idaho Canyon/Mountain region lies north and south from the Cuddy Mountains west of Cambridge to just north of Hells Canyon Dam (Figure 8). Downstream of Brownlee Dam the region is only a little over 5 km (3 mi) wide, as we truncated it on the west at the Idaho boundary of the Snake River. We did not include the Oregon portion due to different cover type map sources and scales. Transmission Lines 905 and 945 run along the western edge of the region adjacent to Oxbow and Hells Canyon reservoirs. Twenty kilometers (12.4 mi) of Lines 904 and 911 bisect the southern end of the region. In all, there are about 91 km (56.5 mi) of lines. The terrain is steep, with grassland at lower elevations changing to shrublands and then to forest at the upper elevations. This region is diverse, having 22 of the 32 corridor cover types. Perennial grassland makes up 33.7% of the region, and dry forest makes up 30.2% (Table 6). The dry forest type is predominantly Pinus ponderosa. Other common cover types are bitterbrush, montane shrub, low sagebrush, and wet forest. In 1992, a large, 7,080-ha (17,500-acre) fire burned on the east side of Hells Canyon Reservoir; that fire accounts for the 2.1% herbaceous burn. Annual grass is only 0.2%, the lowest percentage of all the regions. This estimate agrees with the low amount of annual grass found in the ROW. The extent of water cover type is greatest in this region due to the HCC reservoirs along the western edge. Riparian vegetation occurs throughout the numerous drainages and is most prominent in the Wildhorse River and Brownlee, Indian, and Salt creeks. About 19% of the region is privately owned. Most of this land is in open rangeland, as agriculture is only 0.3% of the region. There is no urban development and almost no disturbed areas, except for the three dam areas.

The major landscape-changing processes in this region include timber harvest, livestock grazing, and wildfires. Livestock grazing occurs throughout the region, and timber harvest occurs on the Payette National Forest, all along the eastern edge. This region is within the Blue Mountains ERU where forest landscapes have been substantially fragmented and many areas have changed from early-seral ponderosa pine to fir cover types (Quigley and Arbelbide 1997). In addition, the aerial extent of grassland and shrubland types has declined and been replaced by exotic plants. However, such replacement does not appear to be the case in the Idaho Canyon/Mountain region.

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Except for one large 1992 fire and one on the very northern edge of the region, the ICBEMP data shows only very small fires in the region. Quigley and Arbelbide (1997) rated this area as having no susceptibility to Bromus tectorum invasion.

4.1.3.5. Oregon Plateau and Canyon At the western end of the study area, the Oregon Plateau and Canyon region contains 84,125 ha (207,877 acres) and is about 109 km (68 mi) long (Figure 8). The region is bounded on the east by the Snake River and on the west by Baker City. Transmission Line 903 and a portion of Line 907 occur within the region and total about 84 km (52 mi). Downstream of Brownlee Dam the region is only a little over 5 km (3 mi) wide, as we truncated it on the east at the Oregon boundary of the Snake River. We did not include the Idaho portion due to different cover type map sources and scales. This region can be broadly characterized as having plateau and foothill landforms in the east-to-west extent and a canyon landform in the northern portion. This region shows the least diversity, having only 11 out of 32 corridor cover types. This lack of diversity is at least partially due to the 200-ha minimum mapping scale. Big sagebrush dominates the landscape, occupying 69%, the greatest percentage of any of the regions. Perennial grassland covers 12.6% (Table 6). The majority of the remaining area is either agriculture (10.6%) or riparian (4.2%) type. The agriculture type occurs in large continuous tracts surrounding four large riparian areas. The riparian habitat was typed by the Oregon GAP as National Wetland Inventory (NWI) palustrine shrubland. This data came from the NWI map, which defines this cover type as vegetated wetlands dominated by woody vegetation less than 6 m tall. Compared with the Idaho GAP riparian areas, the NWI palustrine shrubland appears to be much broader in definition and encompasses much larger areas. Riparian areas occur along two sections of the Powder River and along Eagle and Pine creeks. The water cover type (1.4% of the region) is primarily made up of the HCC reservoirs. About 54% of the region is privately owned, and most of this land is in open rangeland. No urban or disturbed areas show on the map, but the towns of Richland, New Bridge, and Brownlee are present within the region.

The major landscape-changing processes occurring in this region include agricultural development, livestock grazing, and wildfires. Livestock grazing occurs throughout the region. Most of the public land has been grazed since the 1860s (Quigley and Arbelbide 1997). This region is in the Blue Mountains ERU where non-forested areas—grassland and shrubland cover types—have declined from the historical to the current period (Quigley and Arbelbide 1997). The decline is partially attributable to colonizing exotic plants. The extent of annual grass in the region is unclear. Our cover type map shows the region to have no annual grass, even though 6 km (3.7 mi) of the Line 903 ROW is in annual grass. ICBEMP data show susceptibility to Bromus tectorum invasion to be moderate to high for two-thirds of the region and nonexistent for one-third. The data also show little change in the frequency and severity of fires from historical to current times. ICBEMP data show 15 very small fires and 2 moderate-size fires (300–400 ha) in the region between 1986 and 1992. Only 4 small fires within that period have burned within 500 m of the ROW.

4.1.3.6. Wallowa-Whitman National Forest Including only areas that were mapped by cover type by the WWNF, the 60,811-ha (150,267- acre) WWNF region lies within 5 km (3 mi) of Lines 907, 908, 910, or 913 (Figure 8). About

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80% of the region is within the HCNRA. The region is bounded on the east by Hells Canyon Reservoir and on the west by the western edge of the WWNF. About 20% of the region is in wilderness area, and about 30% is open to timber harvest activities (Figures 3–7 in USFS 1999). Wet and dry forest types interspersed throughout the region dominate 62% of it (Table 6). The most common tree species include Pseudotsuga menziesii, Abies grandis, and Abies lasiocarpa, as well as Pinus ponderosa and Pinus contorta. Perennial grassland covers 31% of the remaining area, primarily in the lower-elevation open valleys around the Imnaha River. Annual grassland is not present on the WWNF cover type map for our region, but it is adjacent. There are small shrubfields scattered throughout the region, with some large tracts on the west slope of Hells Canyon Reservoir. All shrub types combined make up less than 5% of the region. Large expanses of riparian habitat occur primarily as a 14-km (8.7-mi) continuous tract of riverine riparian along the Imnaha River and as a 4-km (2.5-mi) tract along Big Sheep Creek. Other than a small area at Imnaha, no urban or otherwise developed areas occur in this region. Only 7.5% of the region is in private land.

The major landscape-changing processes occurring in this region include timber harvest, livestock grazing, and wildfires. In regards to HCC lines, timber harvest activities are limited to Line 907, and most of this is along the Imnaha River corridor. The WWNF region occurs in the Blue Mountains ERU of the ICBEMP. Quigley and Arbelbide (1997) found the forested landscapes of the ERU to be substantially fragmented. In addition, many landscapes that were historically dominated by early seral Pinus ponderosa and Larix occidentalis (western larch) are now dominated by grand fir/white fir and Douglas-fir cover types. Substantial changes in the fire regimes have occurred as a result of fire exclusion and timber harvest practices. In the absence of fire and as a result of excessive livestock grazing, forest cover types have encroached into other physiognomic types. The risk of intense fires on BLM and USFS lands was rated as moderate to high for the ERU based on fires in the 1980s. ICBEMP data show 106 very small and 2 large fires near the transmission lines between 1986 and 1992. Bromus tectorum invasion susceptibility is rated as nonexistent by Quigley and Arbelbide (1997).

4.1.3.7. Oregon Upper Plateau The Oregon Upper Plateau region in the northwest corner of the transmission-line corridor contains 54,377 ha (134,368 acres) and about 46 km (28.6 mi) of lines. This region extends from the western edge of the WWNF west to Enterprise (Figure 8). Most of Line 913 and small portions of Lines 907 and 908 are included in the region. The eastern extent of the region includes forested areas not on the WWNF but interspersed with the WWNF region. The northern and western portions of the region are largely open valleys, foothills, and plateaus. Although this region has 17 cover types, 5 make up 98% of it (Table 6). This make up is at least partially due to the 200-ha minimum mapping scale. Annual grassland dominates the landscape, occupying 38%, the greatest percentage of any of the regions. Perennial grassland and montane perennial grassland combined cover 26% of the region, agriculture covers 18%, and dry forest covers 16.5%. According to the Oregon GAP land cover map, no shrubland occurs in this region. About 74% of the region is privately owned, and most of this land is in open rangeland. Enterprise is the only developed area within the region.

The major landscape-changing processes occurring in this region include timber harvest, agriculture, livestock grazing, and wildfires. Broad-scale landscape conditions for forests in the

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Blue Mountains ERU, where this region is located, were reported in the previous description for the WWNF region (section 4.1.3.6). In non-forested areas, grassland and shrubland cover types have declined from the historical to the current period. This decline is partially attributable to colonizing exotic plants, a trend that appears to be extreme in this region. Wildfires may have played a large role in that colonization; however, private land fire history is unknown. ICBEMP data show a moderate to high risk of severe fires for this region. Fire data recorded by the ICBEMP for BLM and USFS lands show only 22 very small (< 2 acre) fires in the region between 1986 and 1992. It appears that fire has not greatly affected public lands.

4.2. Surveys along Right-of-Way and Service Roads

4.2.1. Rare Plants

We located 63 new occurrences of 9 rare plant species along survey units in the HCC study area. The frequencies of rare plant occurrences within the road/pad location, within the 50-m buffer zone, and beyond the buffer zone appear in Table 7. Species identification and location information for 2 of the occurrences have yet to be confirmed. In Idaho, we located 3 occurrences of Allium aaseae (Aase’s onion), 19 occurrences of Astragalus atratus var. inseptus (mourning milkvetch), 10 occurrences of Rubus bartonianus (bartonberry), 13 occurrences of Stylocline filaginea (hooked stylocline), and 2 suspected occurrences of Astragalus purshii var. ophiogenes (Snake River milkvetch). In Oregon, we located 4 occurrences of Astragalus atratus var. owyheensis (Owyhee milkvetch), 1 occurrence of Bolandra oregana (Oregon bolandra), 10 occurrences of Carex backii (Back’s sedge), and 1 occurrence of Mimulus clivicola (bank monkeyflower). Individual species occurrences are discussed below in sections 4.2.1.1 to 4.2.1.9.

4.2.1.1. Allium aaseae Occurrences Allium aaseae is endemic to southwestern Idaho, with known occurrences in Ada, Boise, Gem, Payette, and Washington counties (Figure 9). Habitats include coarse, well-drained, deep sandy soil on gentle to steep south-facing slopes in open, xeric Purshia tridentata or Artemisia tridentata shrub-steppe communities occurring between elevations 825 and 1,550 m (Mancuso 1995b). The species is on the IPC priority search list for Idaho.

Allium aaseae is currently ranked as a species of concern by the USFWS, and as a sensitive species by the BLM. The IDCDC lists Allium aaseae as rare, but not imperiled at global and state levels. The Idaho Native Plant Society (INPS) includes Allium aaseae on the Global Priority (GP) 3 list and considers the species to have only low-magnitude, non-imminent threats (Appendix 5). As of August 2001, 69 occurrences of Allium aaseae were on file at the IDCDC (2001a). The 3 occurrences located during IPC surveys were located within the known range and expected habitat of the species, therefore supporting the current range description for Idaho. No changes in federal or state status rankings of the species are likely as a result of IPC findings.

We located 3 occurrences of Allium aaseae in Ada County in survey units associated with towers 367 to 371 on Line 904 (Table 8 and Figure 10). Occurrences 1 and 2 were found outside of the service road, within the 50-m buffer zone, while occurrence 3 was found within the service road.

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All 3 occurrences were found at elevations between 975 and 1,085 m, in habitats expected to support the species. Species associated with the occurrences included Purshia tridentata, Alyssum desertorum (desert allysum), Erodium cicutarium (stork’s bill), Aristida longiseta (red threeawn), and Bromus tectorum. The noxious weed Chondrilla juncea (rush skeletonweed) was locally frequent throughout most of surrounding area.

Intensity of non-project road disturbance was rated extreme, and disturbances from agriculture, livestock, road use, and service road construction were all rated high on the survey unit associated with occurrence 1 (Table 9). Moderate impacts by road use, fire, livestock, and service road maintenance and slight impacts from water erosion and recreational disturbance were recorded for units associated with the remaining 2 occurrences. Throughout the area surveyed, livestock grazing, recreational trail use, tower maintenance, and weed invasion (i.e., Bromus tectorum, Chondrilla juncea, and Erodium cicutarium) pose the most likely threats to the occurrences.

4.2.1.2. Astragalus atratus var. inseptus Occurrences Astragalus atratus var. inseptus is endemic to the north edge of the Snake River Plain, with known occurrences in Blaine, Camas, Elmore, Gooding, and Lincoln counties in Idaho (Figure 11). Habitats include grassy Artemisia tridentata communities on stony flats with clay and clay- loam soils below 1,500 m (Barneby 1989, Beck and Cole 2000). The species is on the IPC incidental search list for Idaho.

Astragalus atratus var. inseptus is currently ranked as a species of concern by the Snake River Basin Field Office of the USFWS and as a sensitive species by the BLM. The IDCDC lists Astragalus atratus var. inseptus as globally secure, and, in Idaho, as rare or uncommon, but not imperiled. The variety is listed as rare or uncommon across the range of the species. The INPS includes Astragalus atratus var. inseptus on the GP 3 list and considers the species to have only low, non-imminent threats (Appendix 5). As of August 2001, 60 occurrences of Astragalus atratus var. inseptus were on file at the IDCDC (2001a). The 19 occurrences located during IPC surveys were located within the known range and expected habitat of the species, therefore supporting the current range description for Idaho. No changes in federal or state status rankings of the species are likely as a result of IPC findings.

We located 19 occurrences of Astragalus atratus var. inseptus in south-central Idaho, along survey units associated with Lines 906 and 912. Fifteen occurrences were located in Elmore County, 3 in Gooding County, and 1 in Blaine County (Table 10 and Figure 12). Occurrences were located both within the service road and within the 50-m buffer zone in 10 survey units, in the buffer zone only in 6 units, in both the buffer zone and in the area beyond the buffer zone in 2 units, and in all three areas in 2 units. Occurrences were located between 1,030 to 1,475 m, at a mean elevation of 1,135 m, and were consistently found in Artemisia tridentata/Poa secunda (Sandberg bluegrass) habitat, on shallow-soiled, often rocky flats. Common associates included Purshia tridentata, Allium acuminatum (tapertip onion), hookeri (Hooker’s balsamroot), Bromus tectorum, and Taeniatherum caput-medusae (medusahead wildrye). Cover of noxious weeds in survey units associated with Astragalus atratus var. inseptus occurrences was relatively low, with Chondrilla juncea rare to locally occasional in 4 units, Convolvulus

Hells Canyon Complex Page 35 Effects of Road and Transmission Line Idaho Power Company arvensis (morning glory) locally abundant in 1 unit, and Centauria diffussa (diffuse knapweed) locally rare in 1 unit.

Livestock disturbance and service road construction disturbance were each rated moderate on all units associated with Astragalus atratus var. inseptus occurrences (Table 11). High disturbance ratings for fire were recorded in 3 units, for water erosion in 2 units, and for big game in 1 unit. All other disturbance was minimal. Throughout the area surveyed, livestock grazing, fire, and weed invasion (i.e., Bromus tectorum, Taeniatherum caput-medusae, and Chondrilla juncea) pose the most likely threats to the occurrences.

4.2.1.3. Astragalus atratus var. owyheensis Occurrences Astragalus atratus var. owyheensis occurs within, and in regions immediately adjacent to, the Owyhee Desert, with known occurrences in Owyhee, Twin Falls, and Washington counties in Idaho; Baker and Malheur counties in Oregon; and Elko County in Nevada (Figure 13). Habitats include Artemisia tridentata communities on rocky to clayey flats between 750 and 1,800 m (Barneby 1989). The species is on the IPC incidental search list for Oregon.

The USFWS and the ODA do not rank Astragalus atratus var. owyheensis. The species is listed as sensitive by the BLM. The ORNHP lists Astragalus atratus var. owyheensis as globally secure, and, in Oregon, as rare or uncommon, but not imperiled. The variety is listed as rare or uncommon across the range of the species. The taxon is on the ORNHP watch list, implying that it is one of conservation concern, but it is not currently threatened or endangered (Appendix 5). As of August 2001, 9 occurrences of Astragalus atratus var. owyheensis were on file at the ORNHP (S. Vrilakas, Oregon Natural Heritage Program, pers. comm.). The 4 occurrences located during IPC surveys were located within the known range and expected habitat of the species, therefore supporting the current range description for Oregon. No changes in federal or state status rankings of the species are likely as a result of IPC findings.

We located 4 occurrences of Astragalus atratus var. owyheensis along survey units associated with Line 903 in Baker County, near Keating, Oregon (Table 12 and Figure 14). Occurrences 1 to 3 were found outside of the service road, within the 50-m buffer zone, while occurrence 4 was found both within the service road and within the buffer zone. All occurrences were located between 850 and 975 m in sagebrush-steppe habitat on pale-colored clay soils. Common associates included Artemisia tridentata, Poa secunda, and Elymus elymoides (squirreltail). Cover of noxious weeds was moderate to high throughout the area surveyed. Cardaria draba (hoary cress) was locally occasional to locally abundant in the road and the buffer zone in survey units associated with occurrences 1 to 3 and was locally abundant throughout the entire survey unit associated with occurrence 4. Onopordum acanthium (Scotch thistle) was locally frequent in the buffer zone of the unit associated with occurrence 2 and locally frequent to locally abundant in the road and buffer zone of the unit associated with occurrence 4. Cirsium arvense (Canada thistle) was locally frequent in the buffer zone of the unit associated with occurrence 2.

Disturbance from big game and livestock were rated slight on all units associated with Astragalus atratus var. owyheensis occurrences (Table 13). Disturbance from service road construction was rated slight to moderate on 3 of 4 associated survey units. All other disturbance

Page 36 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line was minimal. Throughout the area surveyed, livestock grazing and weed invasion (i.e., Cardaria draba and Onopordum acanthium) are the most likely threats to the occurrences.

4.2.1.4. Astragalus purshii var. ophiogenes Occurrences Astragalus purshii var. ophiogenes is endemic to the Snake River trench and its immediate tributaries, from Twin Falls County, Idaho, west to the Owyhee River in Malheur County, Oregon. Known occurrences are in Ada, Elmore, Owyhee, and Twin Falls counties in Idaho and in Malheur County in Oregon. The plant is generally found on desertic sandy or gravelly bluffs, river terraces, talus, dunes, or volcanic ash between 700 and 1,075 m and is often associated with Artemisia tridentata/Poa secunda communities (Barneby 1989). The species is on the IPC incidental search list for both Idaho and Oregon.

Astragalus purshii var. ophiogenes is not ranked by the USFWS or the ODA. The species is listed as sensitive by the BLM. The IDCDC and the ORNHP list Astragalus purshii var. ophiogenes as widespread, abundant, and secure globally, and, at the state levels, as rare or uncommon, but not imperiled. The variety is listed as rare or uncommon across the range of the species. Astragalus purshii var. ophiogenes is on the INPS state sensitive list and on the ORNHP watch list, implying that it is one of conservation concern, but it is not currently threatened or endangered (Appendix 5). As of August 2001, 51 occurrences of Astragalus atratus var. owyheensis were on file at the IDCDC, and 26 occurrences were on file at the ORNHP (IDCDC 2001a; S. Vrilakas, Oregon Natural Heritage Program, pers. comm.). The two new IPC occurrence locations have not been verified. The accuracy of location and plant identification information is currently being investigated. Both occurrences occur outside the expected range and at a higher elevation than the endemic occurrences. If identification is verified, the occurrences will probably be regarded as disjunct occurrences of the endemic population. The federal and local status ranks for the species will probably remain unchanged.

We located 2 possible (not yet confirmed) occurrences of Astragalus purshii var. ophiogenes in Lincoln County, Idaho, along survey units associated with tower 621 on Line 912 (Table 14 and Figure 15). Plants in occurrence 1 were found both within the service road and within the 50-m buffer zone. Only occurrence 2 was located within the buffer zone. Both occurrences were located at 1,135 m in flat, open sagebrush-steppe habitat on sandy soils. Common associates included Artemisia tridentata, Sisymbrium altissimum (tumble mustard), and Bromus tectorum. The noxious weed Chondrilla juncea was locally rare throughout the area surveyed. Bromus tectorum dominated the understory across the landscape.

Livestock disturbance was rated extreme, and disturbance from road use and from service road construction were rated moderate on the unit associated with both occurrences of Astragalus purshii var. ophiogenes (Table 15). No other disturbance was recorded. Throughout the area surveyed, livestock grazing and weed invasion (i.e., Bromus tectorum and Chondrilla juncea) pose the most likely threats to the occurrences.

4.2.1.5. Bolandra oregana Occurrences Bolandra oregana occurs along the Imnaha, Snake, and lower Willamette rivers and associated tributaries in Oregon; known locations are in Baker, Hood, Multnomah, Union, and Wallowa

Hells Canyon Complex Page 37 Effects of Road and Transmission Line Idaho Power Company counties. Habitats include seeps, waterfalls, and moist rocky areas between 460 and 1,525 m (Hitchcock and Cronquist 1973). The species is on the IPC incidental search list for Oregon.

Bolandra oregana is not ranked by the USFWS. The ORNHP lists Bolandra oregana as globally secure, and, in Oregon, as rare or uncommon, but not imperiled. The taxon is on the ORNHP watch list, implying that it is one of conservation concern, but it is not currently threatened or endangered. The ODA lists the species as a candidate under the Oregon Endangered Species Act (Appendix 5). As of August 2001, 50 occurrences of Bolandra oregana were on file at the ORNHP (S. Vrilakas, Oregon Natural Heritage Program, pers. comm.). The occurrence located during IPC surveys was located within the known range and expected habitat of the species, therefore supporting the current range description for Oregon. No changes in federal or state status rankings of the species are likely as a result of IPC findings.

We located 1occurrence of Bolandra oregana near Loyd Creek in the 50-m buffer zone of survey unit 908 to 147-A1 (Table 16 and Figure 16). The occurrence was found growing in the cracks of exposed basalt under a small waterfall at 800 m. Overhanging Physocarpus malvaceus (mallow ninebark) branches shaded the plants. Other associates included Elymus glaucus (blue wildrye) and Cystopteris fragilis (brittle bladder-fern). Seven species of noxious weeds were present in the unit associated with the occurrence. Convolvulus arvensis and Dipsacus sylvestris (common teasel) were locally abundant in the road and in the buffer zone. Cynoglossum officinale (houndstongue), Hypericum perforatum (St. Johnswort), and Onopordum acanthium were locally frequent to locally abundant in both the road and the buffer zone, while Cirsium arvense was locally frequent in the buffer zone only.

Livestock disturbance was rated high in the unit associated with the occurrence, while disturbances from road use, service road construction, and water erosion were rated moderate (Table 17). No other disturbance was recorded. Although livestock disturbance and weed invasions are both moderately high within the survey unit, the location of the Bolandra oregana occurrence is such that livestock disturbance is not a likely threat, and because the plants occupy such a narrow niche, invasion by other species is also unlikely.

4.2.1.6. Carex backii Occurrences Carex backii occurs in southern British Columbia, northern Washington, and northeast Oregon east to Utah, Colorado, New York, and Quebec (Hitchcock and Cronquist 1973). In Oregon, it is known to occur in Baker, Grant, Harney, Morrow, Umatilla, Union, and Wallowa counties (Figure 17). Habitats include moist woods and thickets in lowlands to moderate elevations in the mountains (Cronquist et al. 1977). The species is on the IPC incidental search list for Oregon.

Carex backii is not ranked by the USFWS or the ODA. The ORNHP lists the species as widespread, abundant and secure globally, but critically imperiled at the state level (Appendix 5). Plant species are ranked as critically imperiled in the case of extreme rarity (usually 5 or fewer occurrences) or because some factor of their biology making them especially vulnerable to extinction (ORNHP 2001a). Although there are 26 known occurrences of Carex backii in Oregon, most occurrences have fewer than 10 plants (clumps or ramets), and nearly all are reportedly threatened by intensive grazing or timber harvest (S. Vrilakas, Oregon Natural

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Heritage Program, pers. comm.). Therefore, no changes in federal or state status rankings of the species are likely as a result of IPC findings.

We located 10 occurrences of Carex backii in Oregon: 8 in Wallowa County and 2 in Baker County (Table 18 and Figure 18). Occurrences were located in only the service road in 4 survey units, both within the road and the 50-m buffer zone in 2 units, and only in the buffer zone in 6 units. Occurrence 1 was locally abundant in the road, with most plants occurring on road cuts. Occurrences 8 and 9 were locally rare in the buffer zone, and occurrence 10 was rare within the service road. All other occurrences were locally occasional to locally frequent in occurrence. Sites occurred between 670 and 1,645 m, at a mean elevation of 1,265 m, and were consistently found in montane shrub or forested riparian habitats. Common associates included Pinus ponderosa, Pseudotsuga menziesii, Populus trichocarpa (black cottonwood), Physocarpus malvaceus, Prunus virginiana, Symphoricarpos albus (snowberry), Achillea millefolium (common yarrow), and Carex geyeri (elk sedge). Noxious weeds were widespread and generally locally common to locally abundant throughout the majority of units associated with Carex backii occurrences. Cynoglossum officinale was present in all units, while Hypericum perforatum was present in half of the units. Other noxious weeds, present in 3 or fewer units, included Centauria repens (Russian knapweed), Cirsium arvense, Convolvulus arvensis, Dipsacus sylvestris, Onopordum acanthium, Rumex crispus (curly dock), and Taeniatherum caput- medusae.

Disturbance from water erosion and service road construction were each present on 67% of units associated with Carex backii occurrences, each of the two disturbance types having an average rating of moderate. Disturbance from corridor clearing and livestock occurred on 42% and 33% of units, respectively, having an average rating of moderate. All other disturbance types were minimal (Table 19). Throughout the area surveyed, livestock grazing and noxious weed invasion pose the most likely threats to the occurrences.

4.2.1.7. Mimulus clivicola Occurrences Mimulus clivicola occurs in northern Idaho and adjacent Washington to the southern end of the Snake River Canyon, where it occurs along the east slopes of the Wallowa Mountains in Oregon and east into central Idaho (Hitchcock and Cronquist 1973). It is known to occur in Adams, Benewah, Clearwater, Idaho, Kootenai, Latah, Lewis, Nez Perce, Shoshone, Valley, and Washington counties in Idaho and in Baker and Wallowa counties in Oregon (Figure 19). The species is on the IPC incidental search list for both Idaho and Oregon.

Mimulus clivicola is not ranked by the USFWS or the ODA. The BLM lists the species as sensitive. The IDCDC and the ORNHP indicate that at the global level, Mimulus clivicola is not rare and is apparently secure, but that there is cause for long-term concern at the global level. The IDCDC lists the species as rare or uncommon, but not imperiled, at the state level, while the ORNHP lists it as imperiled at the state level. Mimulus clivicola is on the INPS monitor list and on the ORNHP watch list, implying that it is one of conservation concern, but it is not currently threatened or endangered (Appendix 5). As of August 2001, 140 occurrences of Mimulus clivicola were on file at the IDCDC, and 30 were on file at the ORNHP (IDCDC 2001a; S. Vrilakas, Oregon Natural Heritage Program, pers. comm.). The occurrence located during IPC surveys was within the known range and expected habitat of the species, therefore supporting the

Hells Canyon Complex Page 39 Effects of Road and Transmission Line Idaho Power Company current range descriptions for both Idaho and Oregon. No changes in federal or state status rankings of the species are likely as a result of IPC findings.

We located 1 occurrence of Mimulus clivicola near tower 84 on Line 907 in Oregon. (Table 20 and Figure 20). The occurrence was found growing in saturated sphagnum soil, along the banks of a small perennial stream at 1,400 m. Associated species included Physocarpus malvaceus, Carex backii, Delphinium (larkspur) species, Collinsia (blue-eyed Mary) species, and Achillea millefolium. Three species of noxious weeds were present in the unit associated with the occurrence. Cynoglossum officinale was frequent in the service road and rare in the 50-m buffer zone, while Cirsium arvense was locally frequent in the buffer zone only and Hypericum perforatum was rare in the service road only.

Disturbance from corridor clearing, industry, and water erosion were each rated moderate in the unit associated with the occurrence, while disturbance from road use and from big game were rated slight (Table 21). No other disturbance was recorded. In the area surrounding the occurrence, livestock and logging pose the most likely threats to the occurrence.

4.2.1.8. Rubus bartonianus Occurrences Rubus bartonianus is endemic to the Snake River Canyon, occurring in thickets on canyon sides along Hells Canyon Reservoir and a few miles below Hells Canyon Dam (Hitchcock and Cronquist 1973). The species is known to occur in Adams and Idaho counties in Idaho and in Wallowa County in Oregon (Figure 21). Habitats include ravines and talus slopes, often near seeps or other water. The species is on the IPC priority search lists for both Idaho and Oregon.

Rubus bartonianus is listed as a species of concern by the Snake River Field Office of the USFWS and is on the BLM watch list. The IDCDC and the ORNHP list the species as imperiled because of rarity at both the global and state levels. The INPS includes Rubus bartonianus on the GP 2 list and considers the species to have low-magnitude, imminent threats. The ODA lists the species as a candidate under the Oregon Endangered Species Act (Appendix 5). As of August 2001, 9 occurrences of Rubus bartonianus were on file at the IDCDC, and 9 were on file at the ORNHP (IDCDC 2001a; S. Vrilakas, Oregon Natural Heritage Program, pers. comm.). The occurrences located during IPC surveys were within the known range and expected habitat of the species, therefore supporting the current range descriptions for both Idaho and Oregon. No changes in federal or state status rankings of the species are likely as a result of IPC findings.

We located 10 occurrences of Rubus bartonianus in Adams County, along the access road associated with Line 945 (Table 22 and Figure 22). Occurrences were found on steep, rocky, west-facing slopes between elevations 520 and 620 m. Associated species included Sambucus cerulea (blue elderberry), Rhus glabra (smooth sumac), (arrowleaf balsamroot), Lomatium (lomatium) species, and Pseudoroegneria spicata (bluebunch wheatgrass). Eight species of noxious weeds were present in units associated with Rubus bartonianus occurrences. All noxious weeds occurred along side the road, with the exception of Onopordum acanthium and Conium maculatum (poison hemlock). Onopordum acanthium averaged locally frequent along the road in 5 of 15 units and locally occasional in the 50-m buffer zone in 2 of 15 units, while Conium maculatum was locally rare in the buffer zone of 1 unit. Tribulus terrestris (puncturevine) was present along the road in 7 units; Cardaria draba,

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Centaurea diffusa, and Linaria dalmatica (dalmatian toadflax) were each present in 3 units; and Cirsium arvense and Convolvulus arvensis were each present in 2 units. No weeds were noted within the Rubus bartonianus occurrences.

Disturbance on units associated with Rubus bartonianus occurrences was relatively minimal. Industrial disturbance was slight to high in 7 of 15 units, while water erosion was slight to moderate on 6 units and big game disturbance was slight to moderate in 5 units (Table 23). Fire, livestock, and recreational disturbances were each rated slight in 1 unit. No other disturbance was recorded. Throughout the area surveyed, noted threats included road maintenance, reservoir fluctuations, road use, and rockslides.

4.2.1.9. Stylocline filaginea Occurrences Stylocline filaginea occurs in California and northeastern Nevada north to the east Cascade Range of Oregon and portions of southern of Idaho (Hitchcock and Cronquist 1973). It is known to occur in Ada, Blaine, Elmore, Gooding, Lincoln, and Owyhee counties in Idaho and in Baker and Jefferson counties in Oregon (Figure 23). Habitats include open or vernally wet places in valleys and foothills, on shallow basalt soils with cindery surficial gravel. The species is on the IPC incidental search list for Idaho.

Stylocline filaginea is not ranked by the USFWS. The BLM lists the species as sensitive. The IDCDC indicates that at the global level, Stylocline filaginea is not rare and is apparently secure, but that there is cause for long-term concern; at the state level, the species is imperiled in Idaho. The species is on the INPS monitor list (Appendix 5). As of August 2001, 13 occurrences of Stylocline filaginea were on file at the IDCDC. Though only doubling the known Idaho occurrences, the 13 new occurrences located by IPC were so large and widespread that the findings will likely change the status of the species in Idaho. In addition, IPC botanists observed numerous unreported occurrences between survey units associated with Lines 906 and 912 in portions of south-central Idaho. IPC will recommend, at the 2002 meeting of the INPS, that Stylocline filaginea should either be moved from the state monitor list to the review list or be dropped from consideration altogether.

We located 13 occurrences of Stylocline filaginea: 8 in Elmore County, 1 in Gem County, and 4 in Washington County along Lines 904, 911, 906, and 912 from Brownlee to Boise and in the Jerome area (Table 24 and Figure 24). Occurrences were generally found in high, open, rocky sagebrush or grassy flats, on pale to reddish clay soils, between 835 and 1,185 m at a mean elevation of 1,020 m. Common associates included Artemisia tridentata, Artemisia rigida (stiff sage), Allium acuminatum, Epilobium paniculatum (autumn willow-herb), Microsteris gracilis (microsteris), Poa secunda, Bromus tectorum, and Taeniatherum caput-medusae. Four species of noxious weeds were present in units associated with Stylocline filaginea occurrences. Chondrilla juncea averaged locally occasional in the 50-m buffer zone in 46% of units. Convolvulus arvensis averaged locally occasional in both the road and the buffer zone on 3 units, while Onopordum acanthium was locally occasional to locally frequent in 2 units and Euphorbia esula (leafy spurge) was locally frequent to locally abundant in 1 unit.

Disturbances from big game, livestock, road use, and service roads were slight to moderate in all units, while disturbance from fire and water erosion each averaged moderate in 8 units

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(Table 25). Disturbance from non-project roads and off-highway vehicle use was rated slight on 7 units, and agriculture disturbance was slight on 1 unit. No other disturbance was recorded. Throughout the area surveyed, livestock grazing, fire, and weed invasion (i.e., Bromus tectorum and Taeniatherum caput-medusae) pose the most likely threats to the occurrences.

4.2.2. Noxious Weeds

IPC botanists recorded 1,118 occurrences of 17 different noxious weed species on survey units within the HCC study area. At least 1 noxious weed was located on 607 of 785 units surveyed (77%) (Table 26). Widespread noxious weed occurrences are discussed below in sections 4.2.2.1 through 4.2.2.13. Section 4.2.2.14 (Other Weed Occurrences) covers noxious weeds recorded on 3 or fewer units. Tabular results of all noxious weed surveys are presented in Appendix 10.

4.2.2.1. Cardaria draba Occurrences Cardaria draba (hoary cress) is found throughout most of the United States and is extensive in both Idaho and Oregon (Figure 25). It is a perennial species that reproduces by both seed and root segments. The species is common in alkaline soils, but can survive in a wide variety of environmental conditions. It increases with drought and disturbance and is extremely competitive once established. Deep, extensively branching root systems make control of the plant’s spread difficult (Callihan and Miller 1999, Whitson et al. 2000). Cardaria draba is considered noxious in both Idaho and Oregon (Appendix 8).

We located Cardaria draba on 146 of 785 units surveyed (19%). The occurrences averaged locally frequent in the roadway on 121 units, locally frequent in the 50-m buffer zone on 128 units, and frequent outside of the buffer zone on 30 units. Occurrences were highly concentrated in Hells Canyon, with 61 occurrences on Line 903, 57 on Line 904, 10 on Line 905, and 13 on Line 911 (Table 27).

Intensity of livestock disturbance and intensity of disturbance from service road construction each averaged moderate on over 90% of units containing Cardaria draba, while big game disturbance averaged slight to moderate on 73% of units containing the species (Table 28). Other disturbances present on units containing Cardaria draba included water erosion (moderate on 52 units), road use (moderate on 34 units), non-project roads (slight to moderate on 36 units), fire (slight to moderate on 18 units), and off-highway vehicles (slight on 28 units). All other disturbance types were minimal.

4.2.2.2. Centaurea diffusa Occurrences Centaurea diffusa (diffuse knapweed) is widespread in the western half of both the United States and Canada and is extensive in both Idaho and Oregon (Figure 26). Centaurea diffusa is an annual, biennial, or short-lived perennial species that reproduces by seed. It is common along roadsides, in waste areas, and in dry rangeland, but it can survive in a wide variety of environmental conditions. The species increases with drought and disturbance and spreads rapidly. An extremely competitive plant, it often replaces desirable forage species, posing a threat to pastures and rangelands (Callihan and Miller 1999, Whitson et al. 2000). Centaurea diffusa is noxious in both Idaho and Oregon (Appendix 8).

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We located Centaurea diffusa on 29 of 785 units surveyed (4%). The occurrences averaged occasional in the roadway on 21 units, occasional in the 50-m buffer zone on 15 units, and rare outside of the buffer zone on 3 units. Occurrences were concentrated in the northern portion of the study area, with 10 occurrences on Line 907 and 4 on Line 908 (Table 27).

Livestock disturbance and disturbance from service road construction each averaged moderate on 86% of units containing Centaurea diffusa, while disturbance from road use and water erosion each averaged moderate to high on approximately half of the units containing the species (Table 29). Other disturbance present on units containing Centaurea diffusa included non-project roads (moderate on 12 units), big game (slight on 12 units), corridor clearing (moderate to high on 8 units), off-highway vehicles (slight on 7 units), and fire (moderate to high on 5 units). All other disturbance types were minimal.

4.2.2.3. Chondrilla juncea Occurrences Chondrilla juncea (rush skeletonweed) is widespread in the western United States and is extensive in both Idaho and Oregon (Figure 27). It is a perennial species that reproduces primarily by seed but is also spread by tillage. It commonly inhabits roadsides, ditches, rangelands, grain fields, and pastures. Deep, extensively branching root systems make control of the species difficult (Callihan and Miller 1999, Whitson et al. 2000). Chondrilla juncea is noxious in both Idaho and Oregon (Appendix 8).

We located Chondrilla juncea on 212 of 785 units surveyed (27%). The occurrences averaged occasional in the roadway on 116 units, occasional in the 50-m buffer zone on 194 units, and occasional to locally frequent outside of the buffer zone on 79 units. Occurrences were concentrated on lines between Brownlee Dam and Midpoint, with 53 occurrences on Line 904, 31 on Line 906, 70 on Line 911, and 58 on Line 912 (Table 27). Chondrilla juncea was not located on the 7 remaining lines.

Livestock disturbance averaged moderate on 94% of units containing Chondrilla juncea, while disturbance from service road construction and road use averaged moderate on 86% of units. Fire disturbance averaged moderate on 70% of units containing the species (Table 30). Other disturbances on units containing Chondrilla juncea included big game (slight to moderate on 160 units), off-highway vehicles (slight on 117 units), non-project roads (slight to moderate on 94 units), and water erosion (moderate on 109 units). All other disturbance types were minimal.

4.2.2.4. Cirsium arvense Occurrences Cirsium arvense (Canada thistle) is widespread throughout most of the United States and Canada and is extensive in both Idaho and Oregon (Figure 28). It is a perennial species that reproduces by seed and by extensive, colony-forming rhizomes that are readily spread by tillage. It grows in a wide range of soils and environmental conditions, posing threats to cropland, rangeland, pastures, and wetlands. Extensive rhizomes make control of the species difficult (Callihan and Miller 1999, Whitson et al. 2000). Cirsium arvense is noxious in both Idaho and Oregon (Appendix 8).

We located Cirsium arvense on 101 of 785 units surveyed (13%). The occurrences averaged occasional in the roadway on 55 units, occasional to locally frequent in the 50-m buffer zone on

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79 units, and frequent outside of the buffer zone on 4 units. Occurrences were spread throughout the study area with the highest concentrations occurring between Oxbow and Enterprise. We located 41 occurrences along Line 907, between Oxbow and the Imnaha Junction, and 34 occurrences along Line 913, between the Imnaha Junction and Enterprise (Table 27).

Disturbance from service road construction averaged moderate on 88% of units containing Cirsium arvense, while disturbance from livestock and corridor clearing averaged moderate and moderate to high, respectively, on nearly two-thirds of units containing the species. Disturbance present on all units containing Cirsium arvense is summarized in Table 31.

4.2.2.5. Conium maculatum Occurrences Conium maculatum (poison hemlock) grows throughout most of the United States, with extensive occurrences in Idaho. It is found throughout most of western Oregon and in Umatilla and Wallowa counties in northeastern Oregon (Figure 29). A biennial species that reproduces by seed, Conium maculatum inhabits poorly drained soils near streambanks, ditches, and other surface water. It often borders pastures and cropland, threatening perennial crops such as alfalfa. The species contains poisonous alkaloids that are toxic to humans and all classes of livestock (Callihan and Miller 1999, Whitson et al. 2000). Conium maculatum is noxious in both Idaho and Oregon (Appendix 8).

We located Conium maculatum on 10 of 785 units surveyed (1%). The occurrences averaged locally occasional in the roadway on 5 units, locally occasional to occasional in the 50-m buffer zone on 8 units, and was not located outside of the buffer zone. Occurrences were concentrated near Brownlee Dam, with 5 occurrences on Line 904, 1 occurrence on Line 905, and 4 occurrences on Line 911 (Table 27). Conium maculatum was not located on the 8 remaining lines.

Livestock disturbance averaged moderate, and disturbance from service road construction averaged moderate to high on all units containing Conium maculatum (Table 32). Other disturbance present on units containing Conium maculatum included big game (averaged moderate on 6 units), fire (averaged high on 3 units), non-project roads (averaged moderate on 5 units), road use (averaged moderate on 10 units), and water erosion (averaged moderate to high on 7 units). All other disturbance types were minimal.

4.2.2.6. Convolvulus arvensis Occurrences Convolvulus arvensis (field bindweed) is widespread in the United States, except for the southeastern states, and is extensive in both Idaho and Oregon (Figure 30). It is a perennial species that reproduces by seed and creeping roots and often inhabits cultivated fields, waste places, roadbeds, and lawns. Twisting, prostrate stems can form dense mats and often climb other vegetation. With seeds that remain viable for up to 50 years and roots that can penetrate soil up to 20 ft, Convolvulus arvensis is extremely difficult to eradicate (Callihan and Miller 1999, Whitson et al. 2000). Convolvulus arvensis is noxious in both Idaho and Oregon (Appendix 8).

We located Convolvulus arvensis on 75 of 785 units surveyed (10%). The occurrences averaged locally frequent in the roadway on 69 units, locally frequent to frequent in the 50-m buffer zone

Page 44 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line on 53 units, and frequent outside of the buffer zone on 7 units. Occurrences were concentrated in the northern portion of the study area, with 18 occurrences on Line 903, 22 occurrences on Line 904, and 10 occurrences each on Lines 907 and 911 (Table 27).

Livestock disturbance averaged moderate to high and disturbance from service road construction averaged moderate on 97% of units containing Convolvulus arvensis, while water erosion averaged moderate on 70% of units containing the species (Table 33). Other disturbance present on units containing Convolvulus arvensis included big game (slight to moderate on 52 units), fire (slight to moderate on 18 units), off-highway vehicles (slight on 24 units), non-project roads (slight to moderate on 37 units), and road use (moderate on 74 units). All other disturbance types were minimal.

4.2.2.7. Cynoglossum officinale Occurrences Cynoglossum officinale (houndstongue) has been reported in all of the United States except for Alabama, Florida, Louisiana, Oklahoma, South Carolina, and . Infestations are common, but scattered in Idaho and Oregon. A biennial species that reproduces by seed, Cynoglossum officinale often inhabits rangeland, pasture, roadsides, and other disturbed habitat. The species contains toxic alkaloids that can cause liver damage in some mammals (Whitson et al. 2000). Cynoglossum officinale is noxious in Oregon, but not in Idaho (Appendix 8). The distribution of the species in Oregon is illustrated in Figure 31.

We located Cynoglossum officinale on 160 of 299 units surveyed in Oregon (54%). The occurrences averaged locally occasional to occasional in the roadway on 120 units, occasional in the 50-m buffer zone on 132 units, and locally occasional outside of the buffer zone on 9 units. Occurrences were concentrated in the northern portion of the study area, with 74 occurrences on Line 907, 44 on Line 913, 19 on Line 908, 14 on Line 910, and 8 on Line 903 (Table 27).

Disturbance types associated with Cynoglossum officinale are summarized in Table 34. Disturbance from service road construction averaged moderate on 91% of units containing Cynoglossum officinale, while disturbance from livestock averaged moderate on 66% of units containing the species. Other disturbance present on units containing Cynoglossum officinale included big game (slight on 57 units), corridor clearing (moderate to high on 89 units), non-project roads (moderate on 74 units), road use (moderate on 102 units), and water erosion (moderate on 64 units).

4.2.2.8. Dipsacus sylvestris Occurrences Dipsacus sylvestris (common teasel) is widespread in North America and is spreading rapidly in the Northwest. Infestations are common, but scattered, in Idaho and Oregon. Dipsacus sylvestris is a biennial species that spreads by seed and commonly inhabits moist sites such as along irrigation ditches, canals, and disturbed streambanks (Whitson et al. 2000). Dipsacus sylvestris is noxious in Oregon, but not in Idaho (Appendix 8). The species’ distribution in Oregon is illustrated in Figure 32.

We located Dipsacus sylvestris on 39 of 299 units surveyed in Oregon (13%). The occurrences averaged frequent in the roadway on 23 units, frequent in the 50-m buffer zone on 36 units, and frequent outside of the buffer zone on 5 units. Occurrences were concentrated in the northern

Hells Canyon Complex Page 45 Effects of Road and Transmission Line Idaho Power Company portion of the study area, with 18 occurrences on Line 908, 15 on Line 903, 4 on Line 907, and 2 on Line 913 (Table 27). Dipsacus sylvestris was not located on the 8 remaining lines.

Disturbance types associated with Dipsacus sylvestris are summarized in Table 35. Disturbance from service road construction averaged moderate on all units containing Dipsacus sylvestris, while road use averaged moderate on 95% of units and livestock disturbance averaged moderate to high on 90% of units containing the species. Other disturbance present on units containing Dipsacus sylvestris included big game (slight to moderate on 21 units), non-project roads (slight to moderate on 16 units), and water erosion (moderate on 31 units).

4.2.2.9. Euphorbia esula Occurrences Euphorbia esula (leafy spurge) is common in the western and north-central United States and in southern Canada. It is extensive in both Idaho and Oregon (Figure 33). A perennial species, Euphorbia esula reproduces by seed and vigorous rootstalks, and it commonly inhabits unplanted pasture or rangeland along streambanks. The species contains milky latex that can cause irritation of the mouth and digestive tract in cattle and horses (Callihan and Miller 1999, Whitson et al. 2000). Euphorbia esula is noxious in both Idaho and Oregon (Appendix 8).

We located Euphorbia esula on 7 of 785 units surveyed. The occurrences averaged occasional in the roadway on 3 units, frequent in the 50-m buffer zone on 6 units, and frequent outside of the buffer zone on 3 units. Occurrences were located on units associated with Lines 904 and 911. Units containing Euphorbia esula are summarized in Table 27.

Livestock and big game disturbance averaged slight on all units containing Euphorbia esula, while disturbance from road use and from service road construction each averaged moderate on 6 of 7 units containing the species (Table 36). Other disturbance present on units containing Euphorbia esula included water erosion (moderate on 5 units) and off-road vehicles (slight on 5 units). All other disturbance types were minimal.

4.2.2.10. Hypericum perforatum Occurrences Hypericum perforatum (St. Johnswort) is widespread in the western United States and in portions of Canada. It is common in both Idaho and Oregon. A perennial species, Hypericum perforatum reproduces by seed and by underground runners. It commonly inhabits sandy or gravelly soils, but can survive in a variety of environmental conditions, often invading pasture and rangeland. The species contains toxins that can be cumulatively poisonous to livestock, especially to light- pigmented animals (Whitson et al. 2000). Hypericum perforatum is noxious in Oregon, but not in Idaho (Appendix 8). The distribution of the species in Oregon is illustrated in Figure 34.

We located Hypericum perforatum on 69 of 299 units surveyed in Oregon (23%). The occurrences averaged occasional in the roadway on 41 units, occasional in the 50-m buffer zone on 57 units, and occasional to locally frequent outside of the buffer zone on 11 units. Occurrences were concentrated in the northern portion of the study area with 33 occurrences on Line 907, 18 on Line 908, 9 on Line 903, and 5 on Line 910 (Table 27).

Disturbance from service road construction averaged moderate on 91% of units containing Hypericum perforatum, while livestock disturbance averaged moderate to high and water erosion

Page 46 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line averaged moderate on 59% of units containing the species. Other disturbance types present on units containing Hypericum perforatum varied greatly (Table 37).

4.2.2.11. Onopordum acanthium Occurrences Onopordum acanthium (Scotch thistle) is widespread over much of North America and is common throughout Idaho and eastern Oregon (Figure 35). It is a biennial species that spreads primarily by seed. Onopordum acanthium commonly inhabits waste areas, moist areas, and drainages in dry locations. The species is very aggressive and often forms dense, impenetrable stands (Callihan and Miller 1999, Whitson et al. 2000). The species is noxious in both Idaho and Oregon (Appendix 8).

We located Onopordum acanthium on 157 of 785 units surveyed (20%). The occurrences averaged locally occasional to occasional in the roadway on 99 units, occasional in the 50-m buffer zone on 127 units, and occasional outside of the buffer zone on 11 units. Occurrences were widespread, but concentrated in the northern portion of the study area, with 40 occurrences on Line 903, 33 on Line 904, 43 on Line 905, 13 on Line 907, and 16 on Line 911 (Table 27).

Disturbance from livestock and from service road construction each averaged moderate on more than 90% of units containing Onopordum acanthium, while big game disturbance averaged moderate on 75% of units containing the species (Table 38). Other common disturbance types present on units containing Onopordum acanthium included water erosion (moderate on 76 units), road use (slight to moderate on 143 units), off-highway vehicles (slight on 38 units), and non-project roads (slight to moderate on 38 units). All other disturbance types were minimal.

4.2.2.12. Rumex crispus Occurrences Rumex crispus (curly dock) is found throughout North America and is common in both Idaho and Oregon. It is a tap-rooted perennial that reproduces by seed and commonly inhabits wet meadows, ditch banks, and waste areas (Whitson et al. 2000). Rumex crispus is noxious in Oregon, but not in Idaho (Appendix 8). The distribution of Rumex crispus in Oregon is illustrated in Figure 36.

We located Rumex crispus on 41 of 299 units surveyed in Oregon (14%). The occurrences averaged locally occasional to occasional in the roadway on 17 units, locally occasional in the 50-m buffer zone on 35 units, and rare outside of the buffer zone on 1 unit. Occurrences were concentrated in the northern portion of the study area, with 19 occurrences on Line 903, 7 on Line 907, 11 on Line 908, and 4 on Line 913 (Table 27).

Disturbance from service road construction averaged moderate on 93% of units containing Rumex crispus, while road use averaged moderate on 90%, disturbance from livestock averaged moderate to high on 88% and disturbance from water erosion averaged slight to moderate on 76% of units containing the species (Table 39). Other disturbance types present on units containing Rumex crispus varied greatly.

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4.2.2.13. Taeniatherum caput-medusae Occurrences Taeniatherum caput-medusae (medusahead rye) is common in the western United States and is scattered throughout much of Oregon and south-central Idaho. Extremely competitive, this winter annual can out-compete many species, including such aggressive ones as Bromus tectorum. The species is unpalatable to livestock at all growth stages and can cover enough acres to render rangeland useless for grazing (Whitson et al. 2000). Taeniatherum caput-medusae is noxious in Oregon, but not in Idaho (Appendix 8). The distribution of the species in Oregon is illustrated in Figure 37.

We located Taeniatherum caput-medusae on 64 of 299 units surveyed in Oregon (21%). The occurrences averaged frequent in the roadway on 42 units, frequent in the 50-m buffer zone on 63 units, and locally abundant outside of the buffer zone on 18 units. Occurrences were concentrated along Line 903, on 55 units (Table 27).

Livestock disturbance averaged moderate to high on 97% of units containing Taeniatherum caput-medusae, while disturbance from service road construction averaged moderate on 94% of units and big game disturbance averaged slight to moderate on 75% of units (Table 40). Other disturbance present on units containing Taeniatherum caput-medusae included road use (moderate on 60 units), water erosion (moderate on 38 units), non-project roads (slight to moderate on 30 units), off-highway vehicles (slight on 22 units), and fire (slight on 13 units). Other disturbance types were minimal.

4.2.2.14. Other Weed Occurrences Aegilops cylindrica Occurrences Aegilops cylindrica (jointed goatgrass) is common in most areas growing winter wheat in North America, including much of Idaho and much of Benton and Baker counties in Oregon (Figure 38). It is a winter annual that spreads by seed. The species most commonly inhabits cultivated fields, waste areas, and roadsides, but it can also invade grasslands (Callihan and Miller 1999, Whitson et al. 2000). Aegilops cylindrica is noxious in (Appendix 8).

We located 2 occurrences of Aegilops cylindrica along Line 904, on units associated with towers 29 and 32. The plant was locally rare in the roadway of 1 unit and frequent in the roadway of the other unit. No occurrences were located outside of the roadway. Disturbance from service road construction was moderate to high, livestock disturbance was moderate, and big game disturbance was slight in both units, while disturbance from non-project roads was moderate on 1 unit. No other disturbance types were recorded.

Centaurea maculosa Occurrences Centaurea maculosa (spotted knapweed) is widespread in North America and is found throughout Idaho and most of Oregon (Figure 39). It is a biennial or short-lived perennial that reproduces by seed and readily inhabits any disturbed soil. Seed production is prolific, and seeds can remain viable in the soil for 8 years. Early spring growth makes the species highly competitive for soil moisture and nutrients (Callihan and Miller 1999, Whitson et al. 2000). Centaurea maculosa is noxious in both Idaho and Oregon (Appendix 8).

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We located 1 occurrence of Centaurea maculosa on Line 911. The plant was locally abundant in both the roadway and the 50-m buffer zone, but was not observed outside the buffer zone. Livestock disturbance was moderate, while disturbance from agriculture, big game, and water erosion were each slight on the unit. No other disturbance types were recorded.

Centaurea repens Occurrences Centaurea repens (Russian knapweed) is widespread in western North America and is found throughout Idaho and much of Oregon (Figure 40). It is a perennial species that reproduces by seed and adventitious roots and commonly inhabits cultivated fields, orchards, pastures, and roadsides. Extensive, deep root systems with prolific root shoot production make the species difficult to control (Callihan and Miller 1999, Whitson et al. 2000). Centaurea repens is noxious in both Idaho and Oregon (Appendix 8).

We located 3 occurrences of Centaurea repens in the northern portion of the study area, with 2 occurrences on Line 913 and 1 on Line 907. The plant was locally frequent in the roadway on the first unit, locally frequent in the 50-m buffer zone in the second unit, and locally rare in the roadway of the third unit. It was not observed outside of the buffer zone. Disturbance from service road construction was slight on all units, while disturbance from corridor clearing was high on 2 units and disturbance from livestock and from non-project roads were each slight on 2 units. Disturbance from water erosion was moderate on 1 unit and from big game was slight on 1 unit. No other disturbance types were recorded.

Tribulus terrestris Occurrences Tribulus terrestris (puncturevine) is widespread over much of North America and is common throughout most of Idaho and parts of Oregon (Figure 41). It is an annual species that reproduces by seed and commonly inhabits sandy dry or gravelly sites in cultivated fields, pastures, waste areas, and roadsides. Because hard spines on fruit segments can puncture bicycle tires, the species reduces the recreational value of some sites. The spines also damage wool, contaminate hay, and can injure livestock. Tribulus terrestris is noxious in both Idaho and Oregon (Appendix 8).

We located 2 occurrences of Tribulus terrestris, with 1 occurrence each on Lines 903 and 905. The species was locally frequent in the roadway on both units and locally occasional in the 50-m buffer zone in 1 unit. It was not observed outside of the buffer zone. Disturbance from service road construction was moderate to high in both units, while disturbance from big game, livestock, and water erosion were slight to moderate on both units. Road use was high in 1 unit, and off-highway vehicle disturbance was slight on 1 unit. No other disturbance types were recorded.

4.2.3. Disturbances

We rated disturbance types and their intensities on qualitative scales, and so responses of rare plants and noxious weeds to disturbance factors were not directly evaluated. However, some estimation about disturbance impacts can be made based on knowledge of general threats posed by individual disturbance types and on knowledge of habitat requirements of individual plant species. For example, it is known that livestock grazing can alter the structure, function, and

Hells Canyon Complex Page 49 Effects of Road and Transmission Line Idaho Power Company species diversity in grassland ecosystems and reduce cover and diversity of native plant species (Yuguang et al. 2001). It is also known that livestock can increase soil erosion and compaction, increase water erosion potential, trample desirable vegetation, and promote the spread of weedy plant species. In addition, various responses of certain plant species to livestock grazing are recognized. Taeniatherum caput-medusae, for example, is most likely to invade areas in which native vegetation has been weakened by overgrazing, intense fires, or cultivation (Miller et al. 1999), and Cirsium vulgare thrives in heavily grazed pastures, but is rarely found in ungrazed pastures (Beck 1999).

Of the 13 disturbance types evaluated, service road construction was the most commonly observed type throughout the study area. It was recorded on 99% of all kilometers surveyed, with an average intensity rating of moderate. Livestock grazing was the second most commonly observed disturbance type, occurring on 90% of all kilometers surveyed, with intensity ratings of slight to high on 83%, and extreme on 7%, of units surveyed. The frequencies of other disturbance types present on surveyed units are as follows: road use (97%), big game (71%), water erosion (52%), off-highway vehicles (49%), non-project roads (47%), fire (45%), corridor clearing (5%), agriculture and logging (3% each), industry (1%), and residences (< 1%). The distribution of disturbance types throughout the study area is discussed below (section 4.2.3.1 and 4.2.3.2.). Potential impacts of each disturbance type evaluated on survey units are further discussed in sections 4.2.3.1.

4.2.3.1. General Disturbance Types Agricultural Disturbance Agricultural disturbance intensities for individual lines are illustrated in Figure 42 and summarized in Table 41. Agricultural disturbance pertains to disturbance directly attributable to past or present agricultural activities, such as cultivation, habitat conversion, herbicide damage, and erosion and runoff. This disturbance type also includes invasion of exotic species from nearby agricultural seed sources (agricultural disturbance and all other disturbance types are further defined in Appendix 9). Throughout the study area, agricultural disturbance was minimal. No agricultural disturbance was observed on 456 km (97%) of survey units. Slight disturbance was recorded on 11 km of survey units on Lines 904, 906, 907, and 911, and moderate disturbance was recorded on 1.3 km of survey units on Lines 904 and 906.

Some of the possible impacts imposed by agricultural development include habitat destruction or conversion and subsequent loss of species diversity (Hull and Hull 1974, Stribley and Haufler 1999), increased soil or water erosion, water course diversion, water table fluctuation, (Douglas and Johnson 1994, McCann 1999), chemical contamination (Miller 1993, ISDA 2000), and increased opportunity for weedy species to spread and establish (McCollough and Ring 1990, McIvor 1997).

Associated Rare Plants Occurrences of Allium aaseae, Astragalus atratus var. inseptus, and Stylocline filaginea were located on units with agricultural disturbance; however, none of the occurrences were located within sites disturbed by agriculture, and none of the individual rare plant observation forms indicated the presence of direct or indirect agricultural threats.

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Associated Noxious Weeds Eleven species of noxious weeds were present on units with agricultural disturbance. The two most common species present were Chondrilla juncea and Onopordum acanthium. These species have long been widespread in portions of the study area where agricultural disturbance was recorded. All of the species present, in fact, are ones expected to occur throughout the study area. Although historical agriculture likely influenced the spread of noxious weeds in the study area, recent and current agricultural practices have probably had little influence on the presence or spread of noxious weeds along surveyed units.

Big Game Disturbance Big game disturbance intensities for individual lines are illustrated in Figure 43 and summarized in Table 42. Big game disturbance pertains to disturbance, such as clipping or trampling vegetation, that is directly attributable to past or present activities of large, nondomesticated ungulates. The majority of big game disturbance recorded in the study area is from foraging of mule deer (Odocoileus hemionus) and elk (Cervus elaphus). Big game disturbance was observed on 332 km (71%) of survey units. Intensity of disturbance was recorded as slight on 187 km of survey units, moderate on 129 km of units, high on 15 km of units, and extreme on 1.7 km of units. Distribution of disturbance intensities was relatively uniform across the study area. Slight big game disturbance was observed on all lines, moderate disturbance was observed on all lines (except Lines 908, 910, and 951), high disturbance was observed on Lines 904, 905, 907, 911, and 912, and extreme disturbance was observed on only Line 904.

Some of the possible impacts of big game include reduced vegetation cover or biomass, altered vegetation composition or physiognomy (Ostfeld and Canham 1993, Kay 1995, Russell et al. 2001), reduced seed production (Kay 1995), increased soil erosion or compaction (Cole 1988, Clary and Leininger 2000), and increased opportunity for weedy species to spread and establish (Olson 1999, Sheley et al. 1999a).

Associated Rare Plants Five rare plant species were located on units with big game disturbance. Occurrences of Astragalus atratus var. inseptus were in or near 18 units with big game disturbance, with intensity ratings of slight on 11 units, moderate on 6 units, and high on 1 unit. One observation form for one occurrence indicates that pronghorn (Antilocarpa americana) and/or mule deer use was heavy in the area surrounding the occurrence, suggesting that big game may pose a threat to that occurrence. Occurrences of Astragalus atratus var. owyheensis were in or near 4 units with slight big game disturbance, and none of the rare plant observation forms for the species indicate the presence of direct or indirect big game disturbance threats. Occurrences of Carex backii were in or near 8 units that had big game disturbance, with intensity ratings of slight on 6 units, moderate on 1 unit, and high on 1 unit. Rare plant observation forms for these sites did not mention direct or indirect impacts from big game use. Mimulus clivicola was located on 1 unit that had slight big game disturbance. The rare plant observation form for that site indicates that big game use, along with livestock grazing and logging disturbance, pose potential, but not imminent, threats to the occurrence. Occurrences of Stylocline filaginea were in or near 13 units having big game disturbance, with ratings of slight on 6 units and moderate on 7 units. Rare plant observation forms indicate that big game disturbance is of little consequence to the occurrences.

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Associated Noxious Weeds Seventeen species of noxious weeds were present on units with big game disturbance. The 3 most common species present were Chondrilla juncea, Onopordum acanthium, and Cardaria draba, each occurring on over 100 units. Other species widespread on units with big game disturbance include Cynoglossum officinale (houndstongue), present on 57 units; Convolvulus arvensis, present on 52 units; and Taeniatherum caput-medusae, present on 48 units. Due to the widespread occurrence of noxious weed species and the extensive range of big game throughout the study area, it is difficult to infer direct or indirect impacts of big game disturbance relative to spread or presence of noxious weeds on surveyed units.

Corridor-Clearing Disturbance Corridor disturbance intensities for individual lines are illustrated in Figure 44 and summarized in Table 43. Corridor-clearing disturbance pertains to disturbance directly attributable to mechanically removing woody vegetation to maintain nearby or adjacent transmission-line corridors. As the majority of the transmission lines in the HCC cross non-forested lands, corridor disturbance was minimal, affecting only 22 km (5%) of survey units. With one exception, all corridor disturbance observations were made on portions of Lines 907, 908, 910, and 913, which lie within the WWNF in northeastern Oregon. Corridor clearing was rated as slight along 2 km of survey units, moderate along 6 km of survey units, and high along 14 km of survey units within the WWNF. Outside the WWNF, disturbance was rated as moderate along a 0.1-km road segment on Line 911.

Some of the possible impacts imposed by corridor-clearing disturbance include disrupting or displacing wildlife (Ellis et al., 1978, Lidicker 1999); disturbing or destroying wildlife habitat (Anderson et al. 1977, Kroodsma 1987); and altering vegetation composition, physiognomy, or continuity (Luken et al. 1991, 1992; Brisson et al. 1997). Cleared corridors can also act as passageways for the spread and establishment of noxious weed species (GANDA 1996).

Associated Rare Plants Two rare plant species were located on units having corridor-clearing disturbance. Occurrences of Carex backii were in or near 5 units having such disturbance, with ratings of moderate on 2 units and high on 3 units. All occurrences, however, were located away from corridor-clearing disturbance, and rare plant observation forms do not mention direct or indirect impacts from corridor clearing. One occurrence of Mimulus clivicola was located on a unit with moderate corridor-clearing disturbance, but the observation form for the site does not mention direct or indirect impacts from corridor clearing.

Associated Noxious Weeds Eight species of noxious weeds were present on units with corridor-clearing disturbance. The three most common species present were Cynoglossum officinale, present on 89 units; Cirsium arvense, present on 66 units; and Hypericum perforatum, present on 23 units. Other noxious species present occurred on 8 or fewer units. Cynoglossum officinale, Cirsium arvense, and Hypericum perforatum, all common noxious weeds in forested ecosystems, were concentrated in the WWNF (Figure 3), where corridor clearing is most likely to occur. Due to the widespread occurrence of these 3 species in the area, it is difficult to infer direct or indirect correlations

Page 52 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line between the presence of the species and disturbance from corridor clearing. However, characteristics of these 3 species suggest that corridor clearing could enhance the ability of each to establish and survive. Like many noxious weeds, all 3 species are disturbance increasers and would therefore benefit from ground disturbance associated with corridor clearing. In addition, Cirsium arvense tends to grow in open areas, suggesting that openings created by corridor clearing could enhance the species’ survival. Cirsium arvense is often found growing along roadsides, railroad ROW, rangeland, and forest land (Morishita 1999). Likewise, Hypericum perforatum prefers sunny exposures and is known to infest forest clearings, ROW, and neglected land (Piper 1999).

Fire Disturbance Fire disturbance intensities for individual lines are illustrated in Figure 45 and summarized in Table 44. Fire disturbance pertains to disturbance directly attributable to natural, manmade, or prescribed fires. This disturbance type does not include slash pile burning, which is covered under logging disturbance, unless the disturbance extends beyond slash pile burn sites. Fire disturbance was observed on 212 km (45%) of survey units. Disturbance was most common, and intensities were highest, along survey units in non-forested areas, where 202 km of survey units were affected. Outside of the forest, fire disturbance was rated as slight along 44 km of survey units, moderate along 76 km of units, high along 51 km of units, and extreme along 22 km of units. The majority of Lines 907, 908, 910, and 913 lie within forested habitats. Disturbance on Lines 907 and 913 was rated as slight for 8 km of survey units and moderate for 1.0 km of survey units. No disturbance was recorded on Lines 908 or 910.

Some of the possible impacts imposed by fire disturbance include disruption of vegetation composition, structure, and landscape patterns (Stein 1988, Smith 2000); temporary or permanent reduction of productivity and seedling establishment for wildlife forage (Freedman and Habeck 1985, Brown et al. 1999); increased soil erosion or soil nutrient loss (Covington and Sackett 1984, Little and Ohmann 1988); and increased opportunity for weedy species to spread and establish (Hassan and West 1986, Melgoza et al. 1990).

Associated Rare Plants Four rare plant species were located on units with fire disturbance. Occurrences of Allium aaseae were located on 2 units with a fire disturbance intensity of moderate. However, rare plant observation forms do not mention fire disturbance as a direct or indirect threat to the occurrences. Occurrences of Astragalus atratus var. inseptus were in or near 8 units having slight to high fire disturbance. All the occurrences were located within the Snake River Plain and Snake River Plateau regions (sections 4.1.3.1 and 4.1.3.2), in areas with widespread infestations of Bromus tectorum and Taeniatherum caput-medusae. Both of these weedy grass species are known to alter fire frequencies and intensities in sagebrush communities in southern Idaho (ISDA 1999). All rare plant observation forms for Astragalus atratus var. inseptus occurrences cite fire disturbance as an imminent threat, and most cite recent fires in the vicinity of occurrences. One occurrence of Carex backii was located on 1 unit with moderate fire disturbance. The rare plant observation form for this site does not mention fire as a direct or indirect threat. Occurrences of Stylocline filaginea were in or near 9 units having fire disturbance, with ratings of slight on 1 unit, moderate on 7 units, and extreme on 1 unit. Like occurrences of Astragalus atratus var. inseptus, many of the Stylocline filaginea occurrences are

Hells Canyon Complex Page 53 Effects of Road and Transmission Line Idaho Power Company in areas with altered fire regimes due to widespread annual grass infestations, and most rare plant observation forms cite fire as a possible threat to occurrences.

Associated Noxious Weeds Twelve species of noxious weeds were present on units with fire disturbance. With the exception of Chondrilla juncea (present on 70% of fire-disturbed units), these species were present on 10% or fewer of such units. Within the study area, occurrences of Chondrilla juncea were concentrated on Lines 906 and 912, running between Brownlee Dam and Midpoint (near Jerome, Idaho). In addition to extensive livestock grazing and widespread infestation of annual weedy grasses in the area, fire disturbance was observed on 79% of units along these two lines. Although livestock grazing is widespread along Lines 906 and 912 and Chondrilla juncea tends to infest areas weakened by heavy livestock grazing (Sheley et al. 1999b), fire disturbance is also a probable factor in the spread and establishment of the species. The perennial habit and root structure of Chondrilla juncea probably increases its survivability during fire disturbance. The roots of Chondrilla juncea often reach depths of 8 ft and produce shoots that can reach the soil surface from depths of 4 ft (Sheley et al. 1999b).

Industrial Disturbance Industrial disturbance intensities for individual lines are illustrated in Figure 46 and summarized in Table 45. Industrial disturbance pertains to disturbance that is directly attributable to past or present industrial activities such as building, excavating, mining, and paving; the category does not include access roads built for such sites. Throughout the study area, industrial disturbance was very minimal, affecting only 5 km (1%) of survey units. Disturbance was recorded as slight on 2.5 km of survey units on Lines 904, 907, and 913; moderate on 1 km of survey units on Lines 904 and 907; and extreme on 1.7 km of survey units on Line 904.

Some of the possible impacts of industrial disturbance include habitat destruction or conversion, increased soil erosion, and increased opportunity for the weedy species to spread and establish.

Associated Rare Plants Two rare plant occurrences were located on a unit having industrial disturbance, which was rated moderate. However, neither of the occurrences was located within sites affected by the disturbance, and neither of the individual rare plant observation forms indicated the presence of direct or indirect industrial use.

Associated Noxious Weeds Nine species of noxious weeds were present on units with industrial disturbance. Cynoglossum officinale, Cirsium arvense, Onopordum acanthium, and Cardaria draba were the most common species, each present on 4 to 6 of the 29 units. As industrial disturbance was observed on so few units, it is difficult to infer direct or indirect impacts of industrial disturbance relative to the spread or presence of noxious weeds on surveyed units.

Livestock Disturbance Livestock disturbance intensities for individual lines are illustrated in Figure 47 and summarized in Table 46. Livestock disturbance pertains to disturbance that is directly attributable to past or

Page 54 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line present activities, such as grazing or trampling, of large, domestic animals. Livestock disturbance was widespread throughout the study area and was observed on 90% (422 km) of survey units. The distribution of livestock disturbance was relatively even across the study area, with fewer occurrences along roads in forested habitats. Disturbance was rated as moderate on 179 km (38%) of units surveyed. Overall, disturbance was rated as slight along 118 km of survey units, moderate along 179 km of survey units, high along 92 km of survey units, and extreme along 34 km of survey units.

Some of the possible impacts of livestock disturbance include habitat destruction or conversion, alteration of vegetation composition or physiognomy, trampling or denuding of vegetation, increased soil erosion or compaction, increased water erosion potential, and increased opportunity for weedy species to spread and establish.

Associated Rare Plants Seven rare plant species were located on units with livestock disturbance. Occurrences of Allium aaseae were in or near 3 units, with intensity ratings of moderate on 2 units and high on 1 unit. Rare plant observation forms cite livestock grazing as one of the most likely threats to Allium aaseae in the area. Occurrences of Astragalus atratus var. inseptus were in or near 22 units having livestock disturbance, with ratings of slight on 9 units, moderate on 10 units, and high on 3 units. Nearly all of the rare plant observation forms mention livestock grazing as among the likely threats. Occurrences of Astragalus atratus var. owyheensis were in or near 4 units with slight livestock disturbance. Rare plant observation forms indicated that livestock grazing was a potential, but not imminent, threat to occurrences. One occurrence of Astragalus purshii var. ophiogenes was located in a unit having extreme livestock disturbance. The rare plant observation form for this site states that the area is heavily grazed and also overrun with Bromus tectorum. Beck and Cole (2000) note that previous studies suggested that the genus Astragalus increases with livestock disturbance; however, extremely intense disturbance may negatively impact occurrences. One occurrence of Bolandra oregana was located in a unit having high livestock disturbance; however, due to the isolated location of the occurrence, livestock disturbance there is insignificant. Carex backii occurrences were in or near 4 units having livestock disturbance, with ratings of slight on 1 unit, moderate on 1 unit, and high on 2 units. On all observation forms, livestock grazing was cited as an imminent threat. Two forms noted numerous cattle trails and significant trampling in the vicinity of Carex backii occurrences. In spite of the presence of 26 known occurrences of Carex backii within Oregon, the species remains on the state’s critically imperiled list. Most occurrences have fewer than 10 plants (clumps or ramets), and nearly all are reportedly threatened by intensive grazing and/or timber harvest (S. Vrilakas, Oregon Natural Heritage Program, pers. comm.). Occurrences of Stylocline filaginea were in or near 14 units having livestock disturbance, with ratings of slight on 6 units, moderate on 7 units, and high on 1 unit. Rare plant observation forms for the species indicate that livestock grazing, as well as exotic species invasions, pose the most likely threats to occurrences.

Associated Noxious Weeds Seventeen species of noxious weeds were present on units with livestock disturbance. The four most common species were Chondrilla juncea, present on 200 units; Onopordum acanthium, on 145 units; Cardaria draba, on 140 units; and Cynoglossum officinale, on 106 units. These four

Hells Canyon Complex Page 55 Effects of Road and Transmission Line Idaho Power Company species are the most commonly occurring noxious weeds in the study area. Due to the widespread occurrence of noxious weed species and the extensive occurrence of livestock disturbance throughout the study area, it is difficult to infer direct or indirect impacts of livestock disturbance relative to the spread or presence of noxious weeds on surveyed units.

Logging Disturbance Logging disturbance intensities for individual lines are illustrated in Figure 48 and summarized in Table 47. Logging disturbance pertains to disturbance directly attributable to past or present logging activities such as tree removal, slash burning, or construction of roads and landings for the purpose of logging activities. As the majority of the transmission lines in the HCC cross non-forested lands, logging disturbance was minimal, affecting only 14 km (3%) of survey units. Disturbance was recorded as slight on 5 km of survey units on Lines 907 and 913; moderate on 8 km of survey units on Lines 907, 910, and 913; and high on 1 km of survey units on Line 913. No extreme logging disturbance was recorded.

Some of the possible impacts of logging disturbance include habitat destruction or conversion, alteration of species composition, increased soil or water erosion, and increased opportunity for weedy species to spread and establish.

Associated Rare Plants Carex backii was the only plant species located on units having logging disturbance. It occurred on 1 unit with slight logging disturbance and 1 unit with moderate logging disturbance. One occurrence was reportedly located adjacent to a clearing; however, neither rare plant observation form indicated direct or indirect threats from logging activity.

Associated Noxious Weeds Eight species of noxious weeds were present on units with associated logging disturbance. The two most common species present were Cirsium arvense and Cynoglossum officinale, present on 28 and 27 units, respectively. Due to the widespread occurrence of these species, it is difficult to infer direct or indirect correlations between the presence of the species and disturbance from logging activities. However, both species possess characteristics that suggest logging disturbance could enhance their establishment and survivability. Both Cirsium arvense and Cynoglossum officinale are common noxious weeds in forested ecosystems, and, like many noxious weeds, both species are disturbance increasers that would probably benefit from ground disturbance associated with logging activity. In addition, Cirsium arvense tends to grow in open areas, suggesting that openings created by logging could enhance the species survival.

Non-Project Road Disturbance Intensities for disturbance from non-project roads for individual lines are illustrated in Figure 49 and summarized in Table 48. Non-project road disturbance pertains to disturbance directly attributable to non-project roads that merge or intersect with the service road being surveyed. Disturbance from non-project roads was observed on nearly half (218 km) of all survey units. Such disturbance was distributed evenly across the study area. The majority of disturbance (164 km of survey units) was recorded as slight. Disturbance was recorded as moderate on 37 km of survey units, high on 14 km of survey units, and extreme on 2.5 km of survey units.

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Some of the possible impacts of non-project road disturbance include increased soil erosion or compaction, increased water erosion potential, alteration of vegetation composition, and increased opportunity for weedy species to spread and establish.

Associated Rare Plants Five rare plant species were located on units with non-project road disturbance. One occurrence of Allium aaseae was located on a unit with extreme non-project road disturbance; however, the occurrence is located away from disturbed portions of the unit. The rare plant observation form for the site indicates that livestock grazing and invasion of exotic species pose the most likely threats to the occurrences. Occurrences of Carex backii were located in or near 6 units having non-project road disturbance, with ratings of slight on 5 units and moderate on 1 unit. Rare plant observation forms note that activities such as non-project road use pose potential habitat threats as some of the Carex backii occurrences lie within or adjacent to the bed of such roads. While non-project road use is listed as a possible threat, livestock grazing and exotic weed invasion are listed as current, imminent threats to the occurrences. Other rare plant occurrences present on units with non-project road disturbance include Astragalus atratus var. inseptus, in or near 10 units; Stylocline filaginea, in or near 8 units; and Astragalus atratus var. owyheensis, located on 1 unit. Rare plant observation forms for all of these species indicate some combination of livestock grazing, fire, or weed invasion as posing the most likely threats to occurrences. Disturbance from non-project roads is not noted and is apparently inconsequential.

Associated Noxious Weeds Fifteen species of noxious weeds were present on units with non-project road disturbance. The 6 most common species were Chondrilla juncea, present on 94 units; Cynoglossum officinale, on 74 units; Cirsium arvense, on 43 units; Onopordum acanthium, on 38 units; Convolvulus arvensis, on 37 units; and Cardaria draba, on 36 units. As non-project road disturbance pertains to disturbance directly attributable to non-project roads merging or intersecting with the service road being surveyed, such disturbance is intermittent when present. The discontinuity of non-project road disturbance coupled with the widespread occurrence of noxious weeds throughout the study area make it difficult to infer direct or indirect impacts of non-project road disturbance relative to the spread or presence of noxious weeds.

Off-Highway Vehicle Disturbance Intensities for off-highway vehicle (OHV) disturbance for individual lines are illustrated in Figure 50 and summarized in Table 49. OHV disturbance pertains to disturbance directly attributable to OHV use. It includes disturbance from any vehicle capable of using service roads. OHV disturbance was observed on nearly half (229 km) of all survey units. It was distributed relatively even across the study area. The majority of disturbance (198 km of survey units) was recorded as slight; the remainder was recorded as moderate on 29 km of survey units and high on 1 km of survey units. No extreme OHV disturbance was observed.

Some of the possible impacts of OHV disturbance include increased soil erosion or compaction, increased water erosion potential, habitat destruction or conversion, and increased opportunity for weedy species to spread and establish.

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Associated Rare Plants Four rare plant species were located on units with OHV disturbance. Occurrences of Astragalus atratus var. inseptus were in or near 16 units having OHV disturbance, with intensity ratings of slight on 15 units and moderate on 1 unit. One occurrence of Astragalus atratus var. owyheensis was located on a unit with slight OHV disturbance. Occurrences of Carex backii were on 2 units having OHV disturbance, with ratings of slight on 1 unit and moderate on 1 unit. Occurrences of Stylocline filaginea were located in or near 9 units with OHV disturbance, all with ratings of slight. Disturbance from OHV is not noted on any of the rare plant observation forms for these species and is apparently inconsequential.

Associated Noxious Weeds Thirteen species of noxious weeds were present on units with OHV disturbance. The 5 most common species were Chondrilla juncea, present on 117 units; Onopordum acanthium, present on 38 units; Cardaria draba, on 28 units; Convolvulus arvensis, on 24 units; and Taeniatherum caput-medusae, on 22 units. Due to the widespread occurrence of noxious weed species and the presence of OHV use throughout the study area, it is difficult to infer direct or indirect impacts of OHV disturbance relative to the spread or presence of noxious weeds on surveyed units.

Residential Disturbance Residential disturbance intensities for individual lines are illustrated in Figure 51 and summarized in Table 50. Residential disturbance pertains to disturbance directly attributable to residential activities; this category includes current activities, as well as past building and excavating. It does not include access roads built for such sites. Throughout the study area, residential disturbance was minimal, affecting less than 1.2 km (< 1%) of survey units. Eleven survey units on Line 907 were the only units with residential disturbance recorded: 0.9 km of survey units were rated as slight; 0.3 km, as moderate.

Some of the possible impacts of residential disturbance include habitat destruction or conversion, increased soil erosion, and increased opportunity for weedy species to spread and establish. No rare plant species were located on units with residential disturbance. Seven noxious weed species were present on such units; however, no significant evidence infers direct or indirect impacts of residential disturbance relative to the spread or presence of the weeds.

Road Use Road use intensities for individual lines are illustrated in Figure 52 and summarized in Table 51. Road use pertains to the relative amount of traffic a service road receives, rather than to the disturbance the traffic creates. Road use intensity was rated as moderate in nearly 40% of all units surveyed. Overall, this category was rated as slight along 144 km of survey units, moderate along 283 km of survey units, and high along 28 km of survey units. No road use was detected on 12.3 km of survey units, and no extreme road use was observed.

Some of the possible impacts of road use include habitat destruction or conversion, alteration of vegetation composition, denuding of vegetation, increased soil erosion or compaction, increased water erosion potential, and increased opportunity for weedy species to spread and establish.

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Associated Rare Plants Four rare plant species were located on units with road use. Occurrences of Astragalus atratus var. inseptus were in or near 18 units having road use disturbance, with intensity ratings of slight on 6 units, moderate on 10 units, and high on 2 units. One occurrence of Astragalus atratus var. owyheensis was located on a unit with slight road use. Occurrences of Carex backii were located on 3 units having road use disturbance, with ratings of slight on 2 units and moderate on 1 unit. Occurrences of Stylocline filaginea were in or near 14 units having road use, with ratings of slight on 9 units and moderate on 5 units. With the exception of Carex backii, road use disturbance is not mentioned as a potential threat on any of the rare plant observation forms for these species and is apparently inconsequential. Rare plant observation forms for Carex backii indicate that road use may be a potential impact since parts of some occurrences lie within or adjacent to some roads. While road use is listed as a possible threat, livestock grazing and exotic weed invasion are listed as imminent threats to the occurrences.

Associated Noxious Weeds Fourteen species of noxious weeds were present on units with road use. The 4 most common species were Chondrilla juncea, present on 140 units; Cynoglossum officinale, on 47 units; Onopordum acanthium, on 39 units; and Cardaria draba, on 34 units. These 4 species are the most commonly occurring noxious weeds in the study area. Due to the widespread occurrence of noxious weed species and the occurrence of road use throughout the study area, it is difficult to infer direct or indirect impacts of road use relative to spread or presence of noxious weeds on surveyed units.

Service Road Construction Disturbance Intensities for service road construction disturbance for individual lines are illustrated in Figure 53 and summarized in Table 52. Service road construction disturbance pertains to disturbance directly attributable to construction of the service road that was surveyed, including disturbance related to road cuts or tower site pads created when the ROW was constructed. This disturbance includes only the area on or associated with the immediate roadway (i.e., does not include the 50-m buffer zone on each side of the roadway). Slight to extreme service road disturbance was recorded on 99% (462 km) of survey units. This percentage is necessarily high, since service roads were a primary unit of survey in this study. During surveys, 9 km of service roads were not located for 6 survey units on Line 903 and 1 unit on Line 913; therefore, no disturbance was recorded for these units. These units were probably accessible by overland travel when the line was constructed, and so no roads were built. Disturbance was rated as moderate in nearly 70% of all units surveyed. Overall, disturbance was rated as slight along 82 km of survey units, moderate along 321 km of survey units, high along 56 km of survey units, and extreme along 3 km of survey units.

Some of the possible impacts of service road construction disturbance include habitat destruction or conversion, alteration of vegetation composition, denuding of vegetation, increased soil erosion or compaction, increased water erosion potential, and increased opportunity for weedy species to spread and establish.

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Associated Rare Plants Seven rare plant species were located on units with service road construction disturbance. Occurrences of Allium aaseae were on 3 units having such disturbance, with intensity ratings of moderate on 2 units and high on 1 unit. Occurrences of Astragalus atratus var. inseptus were in or near 22 units having service road construction disturbance, with ratings of slight on 4 units and moderate on 18 units. Occurrences of Astragalus atratus var. owyheensis were on 3 units having service road construction disturbance, with ratings of slight on 2 units and moderate on 1 unit. One occurrence of Astragalus purshii var. ophiogenes was in a unit with moderate service road construction disturbance. One occurrence of Bolandra oregana (Oregon bolandra) was located in a unit with moderate service road construction disturbance. Occurrences of Carex backii were in or near 8 units having service road construction disturbance, with ratings of moderate on 6 units and high on 2 units. Occurrences of Stylocline filaginea were in or near 14 units having service road construction disturbance, with ratings of slight on 5 units and moderate on 9 units. Because the service road construction disturbance category pertains to disturbance created in the past by the construction of service roads, it is difficult to evaluate direct or indirect impacts that the disturbance my have on rare plant species. None of the rare plant observation forms noted direct disturbance from service road construction; however, some of the possible threats listed on the forms may be indirectly linked to past construction disturbance.

Associated Noxious Weeds Fifteen species of noxious weeds were present on units having service road construction disturbance. The 5 most common were Chondrilla juncea, present on 171 units; Cynoglossum officinale, on 109 units; Onopordum acanthium, on 62 units; Cirsium arvense, on 57 units; and Hypericum perforatum, on 55 units. Due to the widespread occurrence of noxious weed species and the extensive occurrence of service-road construction disturbance throughout the study area, it is difficult to infer direct or indirect impacts of service-road construction relative to the spread or presence of noxious weeds on surveyed units.

Water Erosion Disturbance Intensities of water erosion disturbance for individual lines are illustrated in Figure 54 and summarized in Table 53. Water erosion disturbance pertains to disturbance directly attributable to flooding or overland flow of water. Such disturbance was observed on 52% (243 km) of survey units. The majority of the disturbance intensity was recorded as slight (23%) or moderate (20%), with only 8% recorded as high and 1.3% as extreme. Distribution of disturbance intensities was relatively uniform across the study area. Slight disturbance was observed on all lines; moderate disturbance was observed on all lines except Lines 906 and 951; high disturbance was observed on all lines except Lines 906, 908, 910, and 951; and extreme disturbance was on Lines 904, 905, 907, and 908.

Some of the possible impacts of water erosion include increased soil erosion, loss or destruction of habitat, and increased opportunity for weedy species to spread or establish.

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Associated Rare Plants Seven rare plant species were located on units having water erosion disturbance. One occurrence of Allium aaseae was located on a unit with such disturbance rated slight in intensity. Occurrences of Astragalus atratus var. inseptus were in or near 9 units having water erosion disturbance, with ratings of slight on 5 units, moderate on 2 units, and high on 2 units. Two occurrences of Astragalus atratus var. owyheensis were located on units having slight water erosion disturbance. One occurrence of Bolandra oregana was located in a unit with moderate water erosion disturbance. Occurrences of Carex backii were in or near 9 units having water erosion disturbance, with ratings of slight on 5 units and moderate on 4 units. Occurrences of Stylocline filaginea were in or near 8 units having water erosion, with ratings of slight on 2 units, moderate on 4 units, and high on 2 units. Water erosion was not listed as a potential threat on any of the rare plant observation forms for these species and is apparently inconsequential.

Associated Noxious Weeds Sixteen species of noxious weeds were present on units having water erosion disturbance. The five most common species were Chondrilla juncea, present on 109 units; Onopordum acanthium, on 76 units; Cynoglossum officinale, on 64 units; Convolvulus arvensis, on 53 units; and Cardaria draba, on 52 units. Water erosion disturbance was generally observed in isolated patches within a given unit and pertained to the condition of survey roads (i.e., whether or not the road contained rills, shallow channels, incised channels, or impassible gullies). Such observations rarely pertained to areas within or beyond the 50-m buffer zone; therefore, it is difficult to infer direct or indirect impacts of water erosion relative to the spread or presence of noxious weeds on surveyed units.

4.2.3.2. General Distribution of Disturbance Types Disturbance types along primary service roads were largely the same for all transmission lines running southeast from Brownlee Dam (Lines 904, 906, 911, 912, and 951). Slight to high livestock disturbance and moderate disturbance from service road construction were present on nearly all units surveyed along these lines, while slight to high fire disturbance was present on 50 to 75% of units in the area. Other major disturbances along lines southeast of Brownlee Dam include big game, road use, and OHV disturbances, with intensity ratings of slight to moderate.

Service roads along Lines 903 and 905 also experience similar disturbance types. Lines 903 and 905 both start at Brownlee Dam and run west and north, respectively, through BLM land. Again, slight to high livestock disturbance and moderate disturbance from service road construction are the primary disturbance types on units along these lines. Big game disturbance was more intense and fire disturbance was less intense along Lines 903 and 905 than on lines running southeast from Brownlee Dam. Big game disturbance averaged slight to moderate on 49.3 km (74%) of units surveyed on Line 903 and averaged moderate on 20.8 km (77%) of units surveyed on Line 905. Fire disturbance was minimal on Line 905 and rated as slight to moderate on 11.5 km (17%) of units surveyed on Line 903. While water erosion disturbance was minimal along lines southeast of Brownlee Dam, it averaged moderate on 37.4 km (56%) of units on Line 903 and 11.5 km (17%) of units on Line 905.

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Lines 907, 908, 910, and 913 run through the WWNF in the northwestern portion of the study area. Disturbance from service road construction and the presence of corridor-clearing disturbance characterize service road disturbance along these lines. Disturbance from service road construction averaged slight to high along these lines, while averaging only slight to moderate on all other lines. Because of the necessity for corridor clearing in forested regions, Lines 907, 908, 910, and 913 were the only lines with observations of corridor-clearing disturbance (with the exception of one observation of slight corridor-clearing disturbance on a small forested unit on Line 911). Corridor-clearing disturbance was rated as slight to high on 21 km (35%) of units surveyed on Line 907, moderate on less than 1 km on Line 908, slight to moderate on 2.6 km (30%) of units on Line 910, and moderate to high on 9.3 km (56%) of units on Line 913. Unlike for all other lines, disturbance from livestock grazing and big game were generally not primary disturbance types on lines in the forested region. Disturbance from livestock was rated as slight to high on 10.4 km (30%) of units surveyed on Line 907, slight to extreme on 10 km (95%) of Line 908, minimal on units on Line 910, and slight to high on 14.5 km (88%) of units on Line 913. Big game disturbance was rated as slight to moderate on 18.7 km (58%) of units on Line 907, minimal on units on Lines 908 and 910, and slight to moderate on 4.9 km (30%) of units on Line 913. Fire disturbance was minimal on Line 907, not observed on Lines 908 or 910, and slight on 5.9 km (36%) of units surveyed on Line 913.

4.2.3.3. Disturbance on Individual Lines Line 903—Brownlee to Quartz Junction The kilometers of each disturbance type, by intensity category, along Line 903 survey units is illustrated in Figure 55. In addition, Table 54 summarizes, for each disturbance type, the percent of survey units in each intensity category. A total of 69.3 km of survey units on this line lie on public land. Most (66.7 km) were fully surveyed, 2.6 km were not surveyed. Livestock disturbance was observed on all but 0.33 km of survey units, with intensity ratings of slight on 17 km, moderate on 28 km, high on 13 km, and extreme on 9 km. Slight to moderate big game disturbance was observed on 49.3 km (or 74% of survey units). Disturbance from service road construction was moderate on 42.7 km (or 64% of survey units), slight on 18 km, high on 2 km, and absent on 2 km. Road use disturbance was relatively light. It was slight on 15.6 km of survey units, moderate on 33.8 km, high on 6.9 km, and absent on 10.4 km. OHV disturbance and disturbance from non-project roads were each slight on approximately 33% of survey units. Water erosion was slight to moderate on 35 km (50% of survey units), high on 3 km, and absent on 30.6 km. Fire disturbance was slight to moderate on 11.5 km of survey units and absent on 57.5 km. No agricultural, corridor-clearing, industrial, logging, or residential disturbances were observed (Table 54).

Line 904—Brownlee to Boise #1 and #2 The kilometers of each disturbance type, by intensity category, along Line 904 survey units is illustrated in Figure 56. In addition, Table 55 summarizes, for each disturbance type, the percent of survey units in each intensity category. On this line, 85.4 km of survey units lie on public land. Most (78 km) were fully surveyed, 5.8 km were subsampled, and 1.5 km were not surveyed. Livestock disturbance was observed on all but 1.9 km of survey units, with intensity ratings of slight on 30 km, moderate on 24 km, high on 15 km, and extreme on 7 km. Big game disturbance was slight on 36 km, moderate on 14 km, high on 1 km, and extreme on 2 km of

Page 62 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line survey units. Disturbance from service road construction was moderate on 48.7 km (62% of survey units), with ratings of slight on 13 km, high on 16 km, and extreme on 0.7 km. Road use and OHV disturbance were rated as slight to moderate on approximately half of survey units. Disturbance from non-project roads was absent on 53.8 km (63% of survey units), with ratings of slight on 22 km, moderate on 3.6 km, high on 2.7 km, and extreme on 0.3 km. Water erosion was slight on 15 km of survey units, moderate on 16.8 km, high on 11.6 km, and extreme on 3.6 km. Fire disturbance was present on 41.8 (49% of survey units), with ratings of slight on 5.4 km, moderate on 10.7 km, high on 12.1 km, and extreme on 2.3 km. Agricultural and industrial disturbances were minimal. No corridor-clearing, logging, or residential disturbances were observed (Table 55).

Line 905—Brownlee to Oxbow The kilometers of each disturbance type, by intensity category, along Line 905 survey units is illustrated in Figure 57. In addition, Table 56 summarizes, for each disturbance type, the percent of survey units in each intensity category. All 27 km of survey units lying on public land on Line 905 were surveyed. Livestock disturbance was observed on all but 2.1 km of survey units, with intensity ratings of slight on 4.6 km, moderate on 8.8 km, high on 10.1 km, and extreme on 1.4 km. Big game disturbance was slight on 5.3 km, moderate on 8.5 km, high on 7 km, and absent on 6.2 km. Moderate to extreme disturbance from service road construction was observed on all survey units, with ratings of moderate on 14 km, high on 11.9 km, and extreme on 1.1 km. Road use was slight on all units. Water erosion was rated as slight on 2.9 km of survey units, moderate on 5.9 km, high 2.3 km, and extreme on 0.4 km. Disturbance from fire, OHV use, and non-project roads was minimal, and no agricultural, corridor-clearing, industrial, logging, or residential disturbances were observed (Table 56).

Line 906—Boise to Midpoint #2 The kilometers of each disturbance type, by intensity category, along Line 906 survey units is illustrated in Figure 58. In addition, Table 57 summarizes, for each disturbance type, the percent of survey units in each intensity category. On this line, 103.1 km of survey units lie on public land. Of these, 58.9 km (57%) were fully surveyed, 41.4 km were subsampled, and 2.8 km were not surveyed. Livestock disturbance was observed on all but 0.9 km of survey units, with intensity ratings of slight on 6.6 km, moderate on 39 km, and high on 12.4 km. Slight to moderate big game disturbance was observed on 40.8 km (69% of survey units). Disturbance from service road construction was moderate on 41.4 km (70% of survey units) and slight on the remaining 17.5 km. Road use was slight to moderate on 56.9 km of survey units. OHV disturbance and disturbance from non-project roads were each rated as slight to moderate on approximately 70% of survey units. Fire disturbance was observed on 45.5 km (77% of survey units), with ratings of slight on 10.4 km, moderate on 20.7 km, high on 9.9 km, and extreme on 4.5 km. Disturbance from agriculture and water erosion was minimal, and no corridor-clearing, industrial, logging, or residential disturbances were observed (Table 57).

Line 907—Oxbow to Pallette Junction The kilometers of each disturbance type, by intensity category, along Line 907 survey units is illustrated in Figure 59. In addition, Table 58 summarizes, for each disturbance type, the percent of survey units in each intensity category. On this line, 31.4 km of survey units lie on public land. Most (30.2 km) were fully surveyed, 1.2 km were not surveyed. Big game disturbance was

Hells Canyon Complex Page 63 Effects of Road and Transmission Line Idaho Power Company observed on 18.7 km (58% of survey units) with intensity ratings of slight on 10.6 km, moderate on 5.9 km, and high on 1.1 km. Livestock disturbance was only observed on 10.4 km (30% of survey units), with ratings of slight on 1.4 km, moderate on 3.3 km, and high on 4.7 km. Slight to high disturbance from service road construction was observed on 29.9 km (99% of survey units), with ratings of slight on 2.4 km, moderate on 19.6 km, and high on 7.9 km. Road use was slight to moderate on 29.7 km of survey units. Disturbance from non-project roads and corridor clearing were each rated slight to high on approximately 35% of survey units. Water erosion occurred on approximately half of survey units, with ratings of slight on 6 km, moderate on 7.3 km, high on 1 km, and extreme on 1.7 km. Agricultural, fire, industrial, logging, and residential disturbances were minimal (Table 58).

Line 908—Pallette Junction to Imnaha The kilometers of each disturbance type, by intensity category, along Line 908 survey units is illustrated in Figure 60. In addition, Table 59 summarizes, for each disturbance type, the percent of survey units in each intensity category. On this line, 10.6 km of survey units lie on public land. Most (10.5 km) were fully surveyed, 0.1 km was not surveyed. Livestock disturbance was relatively high, with observations on all but 0.5 km (4.9% of survey units). Such disturbance was rated extreme in intensity on over half (5.7 km) of survey units and slight on 0.5 km, moderate on 2.4 km, and high on 1.4 km. Big game disturbance was minimal. Disturbance from service road construction was rated as moderate on 9.5 km (90.5% of survey units). Road use disturbance was slight on 0.5 km, moderate on 8.6 km, and high on 1.4 km of survey units. OHV and non-project road disturbances were slight to moderate on 20 to 30% of survey units, and water erosion was slight to moderate on most roads. Corridor-clearing disturbance was minimal, and no agricultural, fire, industrial, logging, or residential disturbances were observed (Table 59).

Line 910—Hells Canyon to Pallette Junction The kilometers of each disturbance type, by intensity category, along Line 910 survey units is illustrated in Figure 61. In addition, Table 60 summarizes, for each disturbance type, the percent of survey units in each intensity category. On this line, 10.8 km of survey units lie on public. Most survey units (8.6 km) were fully surveyed, 2.3 km were not surveyed. Livestock and big game disturbances were rated slight in intensity. Disturbance from service road construction was moderate to high on all survey units. Road use was moderate on 6.2 km (73%) and slight on 2.3 km (27% of survey units). Disturbance from non-project roads was slight on 2.8 km, moderate on 1.4 km, and high on 0.4 km. Disturbance from OHV use was minimal. Water erosion and corridor-clearing disturbances were each rated slight to moderate on approximately 30% of survey units. No agricultural, fire, industrial, logging, or residential disturbances were observed (Table 60).

Line 911—Brownlee to Boise #3 and #4 The kilometers of each disturbance type, by intensity category, along Line 911 survey units is illustrated in Figure 62. In addition, Table 61 summarizes, for each disturbance type, the percent of survey units in each intensity category. On this line, 99.2 km of survey units lie on public land. Most (56.4 km) were fully surveyed, 0.2 km was subsampled, and 22.7 km were not surveyed. Livestock disturbance was observed on all but 5.9 km of survey units, with intensity ratings of slight on 25.1 km, moderate on 30.8 km, high on 13.6 km, and extreme on 0.8 km. Big

Page 64 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line game disturbance was slight on 31.9 km of survey units, moderate on 33.4 km, and high on 2.1 km. Disturbance from service road construction was moderate on 63.1 km (83% of survey units), slight on 6 km, and high 5.5 km. Non-project road and OHV disturbances were slight to moderate on approximately 45% of survey units. Road use disturbance was moderate, with ratings of slight on 22 km, moderate on 50.1 km, and high on 4.1 km. Water erosion was slight on 15.4 km, moderate on 28.8 km, and high on 12.2 km. Fire disturbance was present on 55.6 km of survey units, with ratings of slight on 14.7 km, moderate on 15.9 km, high on 10.1 km, and extreme on 2 km. Agricultural disturbance was minimal, and no corridor-clearing, industrial, logging, or residential disturbances were observed (Table 61).

Line 912—Boise to Midpoint #3 The kilometers of each disturbance type, by intensity category, along Line 912 survey units is illustrated in Figure 63. In addition, Table 62 summarizes, for each disturbance type, the percent of survey units in each intensity category. On this line, 158.8 km of survey units lie on public land. Approximately half (77.1 km) of units were fully surveyed, 64 km were subsampled, and 17.8 km were not surveyed. Livestock disturbance was observed on all but 4.8 km of survey units, with intensity ratings of slight on 16.6 km, moderate on 31.4 km, high on 15.4 km, and extreme on 8.9 km. Slight to moderate big game disturbance was observed on 56.1 km (73% of survey units). Disturbance from service road construction was moderate on 60.9 km (79% of survey units), slight on17.5 km, and high on 3.4 km. Road use disturbance was moderate on 58.8 km (73% of survey units), slight on 10.9 km, and high on 7.3 km. OHV disturbance was slight on the majority (60.1 km) of survey units, moderate on 3.7 km, and high on 1 km. Fire disturbance was observed on 58.8 km (76% of survey units), with ratings of slight on 13.8 km, moderate on 18.9 km, high on 13.8 km, and extreme on 12.4 km. Non-project road disturbance was slight on 34.6 km, moderate on 0.8 km, high on 1.7 km, and extreme on 1.5 km. Water erosion was slight on 20.9 km, moderate on 10.9 km, and high on 4.2 km. No agricultural, corridor-clearing, industrial, logging, or residential disturbances were observed (Table 62).

Line 913—Pallette Junction to Enterprise The kilometers of each disturbance type, by intensity category, along Line 913 survey units is illustrated in Figure 64. In addition, Table 63 summarizes, for each disturbance type, the percent of survey units in each intensity category. For this line, we surveyed all 16.6 km of survey units lying on public land. Livestock disturbance was observed on 14.5 km (88% of survey units), with intensity ratings of slight on 7.4 km, moderate on 2.9 km, and high on 4.1 km. Slight to moderate big game disturbance was observed on 4.9 km (30% of survey units). Disturbance from service road construction was observed on all survey units with ratings of slight on 5.1 km, moderate on 6.8 km, high on 3.3 km, and extreme on 1.5 km. Disturbance from non-project roads was slight on 4.4 km, moderate on 3.7 km, high on 2.5 km, and extreme on 0.5 km. Slight fire disturbance was observed on 5.9 km (36% of survey units). Water erosion was slight on 2.1 km, moderate on 0.9 km, and high on 2 km. Disturbance from corridor clearing was moderate to high on 9.3 km of survey units, with ratings of moderate on 2.1 km and high on 7.2 km. Industrial, OHV, and road use disturbances were minimal, and no agricultural, logging, or residential disturbances were observed (Table 63).

Hells Canyon Complex Page 65 Effects of Road and Transmission Line Idaho Power Company

Line 951—Midpoint to Borah #2 The kilometers of each disturbance type, by intensity category, along Line 951 survey units is illustrated in Figure 65. In addition, Table 64 summarizes, for each disturbance type, the percent of survey units in each intensity category. On this line, 81.9 km of survey units lie on public land. Of these, 18 km (22%) were fully surveyed, and 63.9 km were subsampled. Livestock disturbance was observed on all survey units, with intensity ratings of slight on 5.7 km, moderate on 8.9 km, high on 1.7 km, and extreme on 1.7 km. Slight big game disturbance was observed on 11.2 km (62% of survey units). Disturbance from service road construction was recorded on all survey units, with ratings of slight on 5.7 km and moderate on 12.3 km. Road use was slight to moderate on 16.5 km (91% of survey units), with the remaining 1.7 km (9%) rated as high. Disturbance from non-project roads and OHV use was slight over the majority of survey units. Water erosion was slight on 9.8 km and absent on the remaining 72.1 km. Fire disturbance was observed on 13.3 km (74% of survey units), with ratings of slight on 1.7 km, moderate on 5.5 km, high on 5.1 km, and extreme on 1 km. No agricultural, corridor-clearing, industrial, logging, or residential disturbances were observed (Table 64).

4.3. Operation and Maintenance Activities

O&M activities for transmission lines are presented for each line in Table 65. A summary of O&M activities for individual transmission lines is described below. Both the summary below and the details in Table 65 are based on past maintenance activities and expected future maintenance requirements. We describe activities for the lines as a whole rather than describing site-specific activities. Public and private lands are not separated for these summaries. For each line, we provide a brief description of maintenance activities, including how often these activities occur, the window available for scheduled maintenance, and the predicted level of occurrences of emergency maintenance. Since details of the vegetation management activities are presented in section 4.4.2, we only briefly mention those activities here. Refer to Figure 1 for line location information. An outage window refers to the time of year that a line is allowed to go out of service to facilitate maintenance activities. Scheduled maintenance is coordinated around the heavy load periods so that power delivery and reliability are not compromised.

Line 903—Brownlee to Quartz Junction This 230-kilovolt (kV) single-circuit transmission line runs from Brownlee Dam to Quartz Junction Substation, just west of Baker City (Figure 1). It consists primarily of H-framed wood pole structures (Table 1). There is virtually no need for vegetation management along Line 903 because of the scarcity of forested vegetation. An air patrol of the line is done annually between March and May. Using a helicopter, a 2- or 3-person crew can patrol the line in less than a day. A ground patrol by a single patrolman using a pickup or all-terrain vehicle (ATV) occurs annually between June and October over about a 5-day period. The last climbing inspection took place in 1997; a 4-person crew took about 30 days to complete it. Such an inspection can take place any time of the year, depending on weather. The next scheduled detailed air or climbing inspection is in 2005. In 2000, 4 days of routine annual structure and conductor maintenance occurred. Spring and fall outage windows are available for maintenance. An inspection of the wood pole integrity takes place about every 10 years. The inspection can take place any time of the year and requires about 20 days for a single 6-person crew to complete. The follow-up

Page 66 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line replacement of deteriorated poles was last done in 1998. One 6-person crew required about 32 days to replace poles. We estimate about 6 emergencies within a 10-year time frame for this line.

Line 904—Brownlee to Boise #1 and #2 Line 904 runs between the Brownlee switchyard and the Boise Bench Substation (Figure 1). The line consists of two 230-kV circuits on steel lattice structures (Table 1). Vegetation management consists of limited hazard tree removal and trimming of tall vegetation on approximately 1,260 m (0.08%) of linear ROW, 420 m of which is on public land. An air patrol of this line is done annually between March and May. Using a helicopter, a 2- or 3-person crew can patrol the line in less than a day. A ground patrol by a single person using a pickup or ATV occurs annually between June and October. Line 904 takes about 15 days to patrol from the ground. Approximately every 5 years, the patrolman will test the cathodic protection on steel lattice towers during the normal ground patrol. A detailed aerial inspection takes place approximately every 10 years. In 1999 when the last air inspection took place, a 2-person crew took about 10 days to complete it. Such an inspection can take place from December to February or June through August, depending on weather. Follow-up maintenance to the aerial inspection usually occurs the following year. In 2002, 15 days of follow-up maintenance on structures and conductors was required. Three days of routine annual maintenance occurred the same year. Spring and fall outage windows are available for maintenance. We estimate about 4 emergencies within a 10-year time frame for this line.

Line 905—Brownlee to Oxbow Line 905 runs between the Brownlee and Oxbow switchyards (Figure 1). The line consists of two 230-kV circuits on steel lattice structures (Table 1). Vegetation management occurs on about 120 m (0.67%) of linear ROW, all of which is on public land. In 1999, three 3-person crews required fewer than 2 days to complete vegetation management activities. Cyclical vegetation management on this line occurs every 5 to 10 years. An air patrol of Line 905 is done annually between March and May. Using a helicopter, a 2- or 3-person crew can patrol the line in less than a day. A ground patrol by a single person using a pickup or ATV occurs annually between June and February. Line 905 takes about 1 day to patrol from the ground. Approximately every 5 years, the patrolman will test the cathodic protection on steel lattice towers during the normal ground patrol. A detailed aerial inspection takes place approximately every 10 years. In 2000 when the last air inspection took place, a 2-person crew took about 1 day to complete it. Such an inspection can take place from June through August, depending on weather. Follow-up maintenance to the aerial inspection usually occurs the following year. In 2001, 5 days of follow-up maintenance on structures and conductors was required. Three days of routine annual maintenance occurred the same year. Spring and fall outage windows are available for maintenance. We estimate about 1 emergency within a 10-year time frame for this line.

Line 906—Boise to Midpoint #2 Line 906 runs between the Boise and Midpoint substations (Figure 1). The line consists of a single 230-kV circuit on H-frame wood structures (Table 1). Vegetation management is limited on this line because of the lack of tall shrubs or trees in the ROW. A ground patrol by 2 people using a pickup or ATV occurs annually between April and October. The ground patrol takes about 13 days to complete. A detailed ground or aerial inspection takes place approximately

Hells Canyon Complex Page 67 Effects of Road and Transmission Line Idaho Power Company every 10 years. The next detailed climbing inspection is scheduled for 2002. It will take one 4-person crew about 60 days to complete. Such an inspection can take place from April through October. Follow-up maintenance to the aerial inspection usually occurs the following year. In 2000, 7 days of routine annual maintenance occurred. Outage windows may be available year- round. An inspection of the wood pole integrity takes place about every 10 years. The inspection can take place any time of the year and requires a single 6-person crew about 30 days to complete. The follow-up replacement of deteriorated poles was last done in 1995. One 6-person crew required about 68 days to replace poles. As for emergencies, we estimate about 3 incidents within a 10-year time frame for this line.

Line 907—Oxbow to Pallette Junction Line 907 runs between the Oxbow switchyard and Pallette Junction, along the Imnaha River in Oregon (Figure 1). The line consists of two 230-kV circuits on steel lattice structures (Table 1). Vegetation management occurs on about 6,800 m (20.0%) of linear ROW, of which about 6,500 m is on public land. Four 3-person crews took about 12 days to complete all clearing activities in 2000. The available window for vegetation management on Line 907 is between May and November, depending on weather conditions. Cyclical vegetation management on this line occurs every 5 to 10 years. An air patrol of the line is done annually between March and May. Using a helicopter, a 2- or 3-person crew can patrol the line in less than a day. A ground patrol by a single person using a pickup or ATV occurs annually between June and November. Line 907 takes about 5 days to patrol from the ground. Approximately every 5 years, the patrolman tests the cathodic protection on steel lattice towers during the normal ground patrol. A detailed aerial inspection takes place approximately every 10 years. In 2000 when the last air inspection took place, a 2-person crew took about a day to complete it. Such an inspection can take place from December to February or June through August, depending on weather. Follow-up maintenance to the aerial inspection usually occurs the following year. In 2000, 5 days of follow-up maintenance on structures and conductors was required. Two days of routine annual maintenance occurred the same year. Spring and fall outage windows are available for maintenance. We estimate about 3 emergency incidents within a 10-year time frame for this line.

Line 908—Pallette Junction to Imnaha Line 908 runs between Pallette Junction and the town of Imnaha, along the Imnaha River in Oregon (Figure 1). The line consists of a single 230-kV circuit on H-frame wood structures (Table 1). Vegetation management occurs on about 1,712 m (4.4%) of linear ROW, of which about 1,190 m is on public land. Three 3-person crews took about 18 days to complete all clearing activities in 1999. The available window for vegetation management on Line 908 is between May and November, depending on weather conditions. Cyclical vegetation management on this line occurs every 5 to 10 years. An air patrol of Line 908 is done annually between March and May. Using a helicopter, a 2- or 3-person crew can patrol the line in less than a day. A ground patrol by a single person using a pickup or ATV occurs annually between June and November. Line 908 takes about 4 days to patrol from the ground. A detailed climbing or aerial inspection takes place approximately every 10 years. In 1998 when the last climbing inspection took place, one 4-person crew took about 15 days to complete it. Such an inspection can take place from December to February or from June through August, depending on weather. In 2000, 3 days of routine annual maintenance occurred. Spring and fall outage windows are available for maintenance. An inspection of the wood pole integrity takes place about every 10 years. The

Page 68 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line inspection can take place between March and November and requires a single 6-person crew about 20 days to complete. The follow-up replacement of deteriorated poles was last done in 1999. One 6-person crew took about 16 days to replace poles. As for emergencies, we estimate about 4 incidents within a 10-year time frame for this line.

Line 910—Hells Canyon to Pallette Junction Line 910 runs between the Hells Canyon switchyard and Pallette Junction (Figure 1). The line consists of two 230-kV circuits on steel lattice structures (Table 1). Vegetation management occurs on about 4,150 m (31.9%) of linear ROW, of which 4,115 m occurs on public land. Three 3-person crews took about 13 days to complete line clearing in 2001. The available window for vegetation management on Line 910 is between June and October, depending on weather conditions. Cyclical vegetation management on this line occurs every 5 to 10 years. An air patrol of Line 910 is done annually between March and May. Using a helicopter, a 2- or 3-person crew can patrol the line in less than a day. A ground patrol by a single person using a pickup or ATV occurs annually between June and November. Line 910 takes about 2 days to patrol from the ground. Approximately every 5 years, the patrolman tests the cathodic protection on steel lattice towers during the normal ground patrol. A detailed aerial inspection takes place approximately every 10 years. In 2000 when the last air inspection took place, a 2-person crew took about 11 days to complete it. Such an inspection can take place from December to February or from June through August, depending on weather. Follow-up maintenance to the aerial inspection usually occurs the following year. In 2001, 5 days of follow-up maintenance on structures and conductors was required in 2001. Two days of routine annual maintenance occurred the same year. Spring and fall outage windows are available for maintenance. We estimate about 1 emergency incident within a 10-year time frame for this line.

Line 911—Brownlee to Boise #3 and #4 Line 911 runs between the Brownlee switchyard and the Boise Bench Substation (Figure 1). The line consists of two 230-kV circuits on steel lattice structures (Table 1). Vegetation management occurs on about 930 m of linear ROW, of which about 180 m is on public land. Three 3-person crews took about 2 days to complete all line clearing in 1999. Cyclical vegetation management on this line occurs every 5 to 10 years. An air patrol of Line 911 is done annually between March and May. Using a helicopter, a 2- or 3-person crew can patrol the line in less than a day. A ground patrol by a single person using a pickup or ATV occurs annually between June and November. Line 911 takes about 15 days to patrol from the ground. Approximately every 5 years, the patrolman tests the cathodic protection on steel lattice towers during the normal ground patrol. A detailed aerial inspection takes place approximately every 10 years. In 2000 when the last air inspection took place, a 2-person helicopter crew took about 11 days to complete it. Such an inspection can take place from December to February or June through August, depending on weather. Follow-up maintenance to the aerial inspection usually occurs the following year. In 2001, 16 days of follow-up maintenance on structures and conductors was required. Two days of routine annual maintenance occurred the same year. Spring and fall outage windows are available for maintenance. We estimate about 4 emergencies within a 10-year time frame for this line.

Hells Canyon Complex Page 69 Effects of Road and Transmission Line Idaho Power Company

Line 912—Boise to Midpoint #3 Line 912 runs between the Boise and Midpoint substations (Figure 1). The line consists of a single 230-kV circuit on H-frame wood structures (Table 1). Vegetation management is limited on this line because of the lack of tall shrubs or trees in the ROW. A ground patrol by a single person using a pickup or ATV occurs annually between March and November. The ground patrol takes about 14 days to complete. A detailed ground or aerial inspection takes place approximately every 10 years. The last detailed climbing inspection took place in 1996. One 4-person crew required about 30 days to complete it. Such an inspection can take place from March through November. Follow-up maintenance to the aerial inspection usually occurs the following year. In 2000, 3 days of routine annual maintenance occurred. Outage windows may be available year-round. An inspection of the wood pole integrity takes place about every 10 years. The inspection can take place between March and November and requires a single 6-person crew about 20 days to complete. The follow-up replacement of deteriorated poles was last done in 1997. One 6-person crew required about 25 days to replace poles. As for emergencies, we estimate about 3 incidents within a 10-year time frame for this line.

Line 913—Pallette Junction to Enterprise Line 913 runs between Pallette Junction and the town of Enterprise in eastern Oregon (Figure 1). The line consists of a single 230-kV circuit on H-frame wood structures (Table 1). Vegetation management occurs on about 5,817 m (12.4%) of linear ROW, of which 5,817 m is on public land. Three 3-person crews required about 17 days to complete all line clearing activities in 1997. The available window for vegetation management on Line 913 is between May and November, depending on weather conditions. Cyclical vegetation management on this line occurs every 5 to 10 years. Hazard tree removal or trimming is done on an as-needed basis. In 1999, two 3-person crews took about a day to remove hazards. An air patrol of Line 913 is done annually between March and May. Using a helicopter, a 2- or 3-person crew can patrol the line in less than a day. A ground patrol by a single person using a pickup or ATV occurs annually between June and October. Line 913 takes about 6 days to patrol from the ground. A detailed climbing or aerial inspection takes place approximately every 10 years. In 1998 when the last climbing inspection took place, one 4-person crew took about 20 days to complete it. Such an inspection can take place from March through November, depending on weather. In 2000, 3 days of routine annual maintenance occurred. Spring and fall outage windows are available for maintenance. An inspection of the wood pole integrity takes place about every 10 years. The inspection can take place from March through November and requires a single 6-person crew about 20 days to complete. The follow-up replacement of deteriorated poles was last done in 2000. One 6-person crew required about 18 days to replace poles. As for emergencies, we estimate about 2 incidents within a 10-year time frame for this line.

Line 923—Borah to Brady #2 Line 923 runs between the Borah and Brady substations in eastern Idaho near American Falls (Figure 1). The line consists of a single 230-kV circuit on H-frame wood structures (Table 1). Vegetation management is limited on this line because of the lack of tall shrubs or trees in the ROW. A ground patrol by a single person using a pickup or ATV occurs annually between March and November. The ground patrol takes about a day to complete. A detailed ground or aerial inspection takes place approximately every 10 years. The last detailed climbing inspection

Page 70 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line took place in 2000. One 4-person crew required about 4 days to complete it. Such an inspection can take place from March through November. Follow-up maintenance to the climbing inspection usually occurs the following year. In 2000, 1 day of routine annual maintenance occurred. Spring and fall outage windows are available for maintenance. An inspection of the wood pole integrity takes place about every 10 years. The inspection can take place from March through November and requires about 3 days for a single 6-person crew to complete. The follow-up replacement of deteriorated poles was last done in 2000. A 6-person crew needed about 2 days to replace the poles. As for emergencies, we estimate about 3 incidents within a 10-year time frame for this line.

Line 945—Oxbow to Hells Canyon Line 945 runs between the Oxbow and Hells Canyon dams (Figure 1). The line consists of a single 69-kV circuit on single-pole, wood structures (Table 1). Vegetation management occurs on about 240 m of linear ROW, of which about 180 m is on public land. It took a 3-person crew about 3 days to complete in 1998. Cyclical vegetation management on this line occurs every 5 to 10 years. Hazard tree removal or trimming is done on an as-needed basis. The line parallels a paved road most of the distance. A ground patrol by a single person using a pickup or ATV occurs annually between August and September. The ground patrol takes about a day to complete. In 2000, 3 days of routine annual maintenance occurred. Maintenance on this line can occur year-round. An inspection of the wood pole integrity takes place about every 10 years. The inspection can take place any time of the year and requires a single 6-person crew about 20 days to complete. The follow-up replacement of deteriorated poles was last done in 1999. One 6-person crew needed about 15 days to replace poles. As for emergencies, we estimate about 4 incidents within a 10-year time frame for this line.

Line 951—Midpoint to Borah #2 Line 951 runs between the Midpoint and Borah substations in eastern Idaho (Figure 1). The line consists of a single 345-kV circuit on H-frame wood structures (Table 1). Vegetation management is limited on this line because of the lack of tall shrubs or trees in the ROW. A ground patrol by a single person using a pickup or ATV occurs annually between March and November. The ground patrol takes about 8 days to complete. A detailed ground or aerial inspection takes place approximately every 10 years. In 1990 when the last air inspection took place, a 2-person helicopter crew took about 8 days to complete it. Such an inspection can take place from January to May or from September through December, depending on weather. Follow-up maintenance to the aerial inspection usually occurs the following year. In 2000, 3 days of routine annual maintenance. An outage window is available between May and August for maintenance. An inspection of the wood pole integrity takes place about every 10 years. The inspection can take place from March through November and requires about 45 days for a single 6-person crew to complete. The follow-up replacement of deteriorated poles was last done in 1991. One 6-person crew needed about 50 days to replace poles. As for emergencies, we estimate about 5 incidents within a 10-year time frame for this line.

Line 952—Midpoint to Adelaide Tap Line 952 is a short tap that runs between the Midpoint Substation and Adelaide Tap in eastern Idaho. The line consists of a single 345-kV circuit on H-frame laminated wood structures (Table 1). Vegetation management is limited on this line because of the lack of tall shrubs or trees in the

Hells Canyon Complex Page 71 Effects of Road and Transmission Line Idaho Power Company

ROW. A ground patrol by a single person using a pickup or ATV occurs annually between March and November. The ground patrol takes about a day to complete. A detailed ground or aerial inspection takes place approximately every 10 years. In 2001 when the last air inspection took place, a 2-person helicopter crew took less than a day to complete it. Such an inspection can take place from January to May or from September through December, depending on weather. Follow-up maintenance to the aerial inspection usually occurs the following year. In 2000, 1 day of routine annual maintenance occurred. An outage window is available between May and August for maintenance. As for emergencies, we estimate about 1 incident within a 10-year time frame for this line.

4.4. Transmission Line Effects on Vegetation

4.4.1. Rights-of-Way Effects on Landscape Level Vegetation Patterns

In this section we report the results of spatial analysis of cover types that intersect either the ROW or the comparison areas that are 1 km from, and on either side of, the ROW. The spatial analysis process often selected very large continuous patches of vegetation that extended up to 220 km from the ROW. In the Snake River Plain region, the hectares of vegetation patches selected for the ROW and comparison areas were very similar (only 0.2% different), had a high level of overlap and thus had similar composition, and were very large (~1,776,000 ha, Table 66). By comparison, the actual ROW is 1,126 ha. The selected patches for the Snake River Plateau and Payette Valley regions were also very large compared with their ROW, and vegetation composition in these two regions was similar to that of the comparison areas of each (Table 66). The eastern comparison area in the Idaho Canyon/Mountain region and the southern side of the WWNF region intersected with very large continuous forest vegetation polygons, so their total hectares for comparison areas are five and two times larger, respectively, than the ROW hectares (Table 66). Like the total hectares, the number of patches in the ROW and comparison areas was similar for the Snake River Plain, Snake River Plateau, and Payette Valley regions (Table 66). The eastern comparison area in the Idaho Canyon/Mountain region had 68% more patches (412 vs. 280 in the ROW) than the ROW did. On the WWNF, the ROW had the most patches (131 vs. 91 and 102 in the comparison areas) because we used our map of ROW cover types.

Region-specific spatial composition and configurations are presented below. Figures 66 through 70 were designed to show the extent of overlap between patches selected in the ROW and those selected in comparison areas. The figures do not show cover types, but they can be interpreted to a certain degree for the dominant types within each region by using Table 66. We did not evaluate the effect of ROW on landscape-level vegetation patterns for the Oregon Plateau and Canyon and the Oregon Upper Plateau regions because the available data did not support these analyses (see section 3.4.1.).

Snake River Plain At the scale at which we conducted our examination, we found no apparent differences in spatial composition and configuration between the ROW and the surrounding vegetation in the Snake River Plain region at the scale that we conducted our examination. Vegetation patches that

Page 72 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line intersected the ROW and comparison areas extended up to 140 km north of the ROW and 55 km south of the ROW (Figure 66). These patches are predominately very large continuous cover types of sagebrush and agriculture that continue through all three areas (ROW and two comparison areas). There is an extremely high extent of overlap among the vegetation patches common to all three areas (Figure 66). Agriculture makes up 48% of the selected patches, and sagebrush makes up 47% (Table 67). Most of the remaining areas are perennial grass (4%). Each comparison area has several other uncommon cover types (Table 67). The ROW intersects 15 cover types, the north comparison area intersects 11 cover types, and the south comparison area intersects 13 cover types (Table 67). Cover types not present in the ROW but present in surrounding areas include wetland (1 patch) and bitterbrush (1 patch).

If the presence of the ROW is changing the vegetation landscape, we might expect to see more patches in the ROW, yet the number of patches differed only slightly between the ROW and two comparison areas. The south side has the most patches—398, the ROW has 383, and the north side has the least—355 (Table 67). If the presence of the ROW is fragmenting the vegetation landscape, we might also expect to see a smaller mean patch size in the ROW than in surrounding areas. However, if we look at the three most dominant cover types, the mean patch sizes in the ROW are between the values for patch sizes in the two comparison areas. All three areas are similar in patch size, and their standard deviations are large and similar. Mean agricultural patch sizes ranged from 95,584 ha on the south side of the ROW to 142,860 ha on the north side (Table 67), a difference of 33%. However, the standard deviations are large (due to only 6 to 9 agriculture polygons), so this difference is not statistically significant. Differences among mean patch size and patch size standard deviation can be difficult to evaluate because a small sample size can dramatically change the results. Also, because the vegetation patches are very large in this region, all three areas often selected the same patches. If one area selected just one additional patch, this difference could substantially change the patch size and standard deviation. Mean sagebrush patch size ranges from 7,117 ha on the north side, to 7,785 ha in the ROW, to 8,092 ha on the south side. Comparison areas are 4% to –9% different from the ROW for patch size. The standard deviations in this case are 10 times larger than the mean patch sizes, indicating that sagebrush patch size is highly variable. Among the three areas, there are 103 to 117 sagebrush patches. Mean patch size for perennial grass ranges from 485 ha to 575 ha, with the ROW having a value between these. Comparison area patch values are 7% to –10% different from the ROW values. The standard deviations in this case are 10 times larger than the mean patch sizes, indicating that perennial grass patch size is highly variable.

Snake River Plateau As for the Snake River Plain, we found no apparent differences in spatial composition and configuration between the ROW and the surrounding vegetation in the Snake River Plateau region. Vegetation patches intersecting the ROW and comparison areas extend up to 220 km north of the ROW but only 10 km south of the ROW (Figure 67). The hectares of vegetation patches selected for the ROW and comparison areas are nearly the same and very large (~920,000 ha, Table 66). In comparison, the actual ROW is 986 ha. Many of the vegetation patches selected in the Snake River Plain region were also selected for the Plateau region. These patches are almost exclusively large, continuous cover types of sagebrush that continue through all three areas (ROW and two comparison areas). There is an extremely high extent of overlap among the vegetation patches common to all three areas (Figure 67). Sagebrush makes up 94%

Hells Canyon Complex Page 73 Effects of Road and Transmission Line Idaho Power Company of the vegetation selected (Table 68). Most of the remaining areas are burned herbaceous cover (2%), perennial grass (2%), agriculture (1%), and rabbitbrush (0.4%). Each area has several other uncommon cover types (Table 68), with the exception of bitterbrush (0.8%), which is only in the north comparison area. The ROW intersects 12 cover types, the north comparison area intersects 15 cover types, and the south comparison area intersects 11 cover types (Table 68). Cover types that are not present in the ROW but that are present in surrounding areas include water (5 patches), dry forest (2 patches), montane shrub (1 patch), mountain big sage (2 patches), and wet meadow (1 patch).

The number of patches in the Snake River Plateau region differs only slightly among the three areas, but is almost twice the number as in the Snake River Plain region. This greater number of patches is due to the lack of large agriculture patches and the inclusion of more perennial grassland and other less common shrub and grassland types. As with the ROW in the Snake River Plain region, the ROW in the Snake River Plateau has a value for the number of patches that is between those of the comparison areas—not the greatest number that one would expect if the ROW had fragmented the habitat. The north side has the most patches—629, the ROW has 606, and the south side has 621 (Table 66). There are 148 to 189 sagebrush patches among the three areas. Mean sagebrush patch sizes are a little smaller than in the Snake River Plain region (7,117 to 8,092 ha) and range from 5,848 ha on the south side, to 5,508 ha in the ROW, to 4,572 ha on the north side (Table 68). Comparison area differences from the ROW are 6% to −17%. The standard deviations in this case are ten times larger than the mean patch sizes, indicating that sagebrush patch size is highly variable and that differences among the comparison areas are not statistically significant. Mean patch size for burned herbaceous cover (the second most dominant type) ranges from 17,729 ha (sample of 1 patch) to 1,3845 ha (sample of 13 patches). There is one large (17,729 ha) burn on the north side of the ROW, along with many smaller burns in the same general area. Perennial grassland and agricultural patches are very similar among the three areas. This region has a fair number of patches of other cover types, such as rabbitbrush, annual grassland, salt desert shrub, low sagebrush, bitterbrush, and riparian. Most of these cover types are fairly similar among the three areas. Rabbitbrush increases from north to south, and mean patch size decreases. Mean patch size of annual grassland is slightly smaller in the ROW than in adjacent areas (28 ha vs. 40 ha). Low sagebrush is the least common cover type in the ROW, but it has a mean patch size (8 ha) similar to that in the comparison areas.

Payette Valley The Payette Valley region has much smaller mean patch sizes, more patches, and an overall greater diversity of cover types than do the Snake River Plain and Plateau regions to the east. As in the eastern regions, we found no apparent significant differences in spatial composition and configuration among the ROW and comparison areas; however, we noted some trends. Vegetation patches intersecting the ROW and the two comparison areas extend up to 35 km west of the ROW and 10 km east of the ROW (Figure 68). There is about 50% overlap of the vegetation patches selected for all three areas. The amount of total hectares is much smaller than in the eastern regions (~140,000 ha, Table 66). In comparison, the actual ROW is 1,140 ha. Perennial grass, high density urban (Boise), sagebrush, bitterbrush, and agriculture are the dominant cover types for all three areas (Table 69). Dry forest also contributes to the western area (11.5%). Most of the subdominant cover types are common to all three areas. The ROW intersects 17 cover types, and the east and west comparison areas intersect 18 cover types

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(Table 69). Cover types not present in the ROW but present in surrounding areas include highly disturbed land (1 patch) and wetland (1 patch).

The Payette Valley region intersects have almost twice the number of patches than the Snake River Plateau region (the region having the next highest number of patches). Overall, the ROW has the most patches—1,191, the east side has 1,145, and the west side has 1,115 (Table 66). For three cover types, the number of patches in the ROW is 7 to 15% higher than in the surrounding areas: perennial grassland (276 vs. 260 patches), sagebrush (185 vs. 158 patches), and bitterbrush (273 vs. 254 patches) cover types. For the remaining cover types, the number of patches in the ROW is either similar to the other areas or a number between that of the comparison areas. Despite more patches in the three cover types, the mean patch size in the ROW is comparable to that in the other two areas, except for sagebrush, for which patch size is smallest in the ROW (126 ha vs. 149 and 177 ha). However, when we look at standard deviations, these differences in patch sizes for these three cover types are not significant. It is interesting to note that among the regions, the mean patch size for sagebrush dropped from about 7,600 ha in the Snake River Plain region and about 5,200 ha in the Snake River Plateau region to about 150 ha in this region. This region has a fair number of patches of other cover types, such as annual grassland, low sagebrush, montane shrub, riparian, water, and mountain big sage. Most of these cover types are fairly similar among the three areas in terms of mean patch size. Annual grassland increases from east to west, and mean patch size is lowest in the ROW (15 ha). Mean patch size of the three shrub types is similar (4 to 13 ha) and much smaller than sagebrush (126 to 177 ha).

Idaho Canyon/Mountain For the Idaho Canyon/Mountain region, we found some differences in the spatial composition and configuration of vegetation patches intersecting the ROW and the comparison area 1 km to the east. Elevational changes due to steep slopes in this reach of Hells Canyon can result in changes in vegetation within relatively short distances. The comparison area intersected one exceptionally large (289,590 ha) dry forest patch near Line 945, a patch that extends 88 km from the ROW (Figure 69). In contrast, the farthest patch that intersects the ROW, also dry forest, extends 28 km. The single dry forest patch accounts for the large difference in total hectares between the ROW and the comparison areas (330,996 ha vs. 61,102 ha) (Table 66). Ninety-six percent of the comparison area is dry forest, and most of the remaining 4% is perennial grass (Table 70). In contrast, only 73% of the area intersected by the ROW is dry forest, and 21% is perennial grassland. The ROW and comparison areas both have small proportions of several shrub and riparian cover types (Table 70).

The presence of the ROW does not appear to have increased the number of habitat patches or to have reduced mean patch size. The comparison area has 132 more vegetation patches than the ROW, a difference greater than in any of the other regions (Table 66). There are almost twice as many dry forest, bitterbrush, montane shrub, and riparian patches 1 km east of the ROW than in the ROW (Table 70). This difference is probably because diversity increases as habitats change from canyon open grassland types to forested areas. Mean patch size for the bitterbrush, montane shrub, and riparian cover types is similar between the two areas. Mean patch size for the dry forest cover type in the comparison area is substantially larger (5,200 ha) than the ROW area (1,661 ha) due to the inclusion of the one large forest patch in the comparison area. However,

Hells Canyon Complex Page 75 Effects of Road and Transmission Line Idaho Power Company even with this very large difference, the standard deviations for both areas are large and the range of possible patch values overlap.

Wallowa-Whitman National Forest About 50 km of transmission-line ROW are in the WWNF region. Cover types on about 24 km of the ROW appear to be changed from adjacent forest cover types. About 17 km have changed from a forest to a non-forested type, mostly montane shrub. About 7 km have changed from a non-forest type to a different non-forest type. In the present analysis, using the true ROW habitat patches, we found the ROW to be intercepting about 56,000 ha and 131 vegetation patches (Table 66). In contrast, the north/east comparison area intersected about 57,000 ha and 102 patches, and the south/west comparison area intersected about 98,000 ha over 91 patches. One wet forest patch in the south/west area accounts for 60% of the area (~58,000 ha). There is a high extent of overlap among the vegetation patches common to all three areas, especially near Lines 910 and 908 (Figure 70). This overlap indicates that the presence of the ROW has not caused habitat fragmentation in these areas. Habitat patches running through the ROW extend at least as far as 1 km on either side of the ROW and usually much farther.

The ROW and the north/east areas have similar proportions of cover types. Along Lines 908, 910, and 913, the ROW intercepts most of the same patches as the north/east area (Figure 70). The northern half of Line 907 did not intercept the same habitat patches because the riverine riparian habitat does not extend out to 1 km. For both these line areas, wet forest (~37%), perennial grassland (~32%), and dry forest (~29%) make up 98% of the vegetation selected (Table 71). Proportionally, the amount of riparian (0.9%) cover is similar between the two areas, but the ROW has 5 patches of riparian, while the north/east area has only 1 patch. In the south/west comparison area, wet forest dominates (63%), and perennial grassland (20%) and dry forest (17%) codominate. Most of the remaining cover types for all three areas are riparian (0.5−0.9%), rock (0.3–0.6%), and montane shrub (0.2–0.3%). There appears to be greater habitat diversity in the ROW as it intersects 13 cover types, twice as many as the two comparison areas intersect. This higher number of cover types in the ROW, however, may be due to our ground surveys detecting the less common cover types.

A few differences are evident between the ROW and comparison areas regarding the number of patches and mean patch size. Overall, the ROW has the most patches in the WWNF region (131 vs. 91 and 102). Again, this higher number is likely due to our ground surveys. The WWNF cover type map was not designed to detail such narrow habitat patches as the 30-m ROW. Specifically, the ROW has fewer wet and dry forest and perennial grassland patches than both adjacent comparison areas (Table 71). But it does have many more montane shrub (39 vs. 11), alpine shrub (7 vs. 0), riparian (5 vs. 1), and dry meadow (12 vs. 0) patches.

Mean patch sizes for the wet forest cover type are very different among the three areas. The south/west area has a mean patch size of 6,182 ha, compared with 1,465 for the ROW and 970 for the north/east area (Table 71). The large size for the south/west area is due to one very large (57,817 ha) patch. The standard deviations in this case are about three times larger than the mean patch sizes, indicating that wet forest patch size is highly variable and that differences among the comparison areas are not statistically significant. Mean patch size for perennial grassland (the second most dominant type) is similar among the three areas (444–594 ha). Montane shrub mean patch size in the ROW (4 ha) is much smaller than in the comparison areas (11–28 ha).

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4.4.2. Operation and Maintenance Effects on Vegetation

To assess the influence of O&M activities on vegetation, we used an O&M Activity Index (Activity Index) and O&M Risk Index (Risk Index) (see section 3.4.2.) to represent potential O&M impacts at two different scales. The Activity Index is applicable on a broad scale—to an entire transmission line. The Risk Index is applied on a fine scale—to single road survey units or transmission tower sites. Categories for each rating, from most impact to least, are termed highest, moderate, moderately low, and low.

4.4.2.1. Effects on General Vegetation The Activity Index represents the relative level of presence of O&M activities, and thus the potential impact that O&M activities may have, on any one area of a transmission line ROW (Table 72). Line 923 had the highest Activity Index at 19.0. It is the only line that was classified in the highest potential impact category. This line traverses private land and a small section of state land. Land use along this transmission line is primarily agriculture, and therefore the line is unlikely to impact native plant communities. Lines 910, 908, and 907 were all classified as having a moderate impact potential, with Activity Indices of 14.4, 12.4, and 9.7, respectively. These lines are on the WWNF, and the survey units of the lines parallel and intersect the Imnaha River. Vegetation clearing is the primary activity contributing to the Activity Index level for these lines. Vegetation clearing and its impacts are addressed more site specifically in section 4.4.3. Lines 913, 945, 905, and 903 are all classified as having a moderately low impact potential, with Activity Indices of 7.8, 7.1, 5.7, and 5.6, respectively. Vegetation clearing on these lines is more site specific, and several of these lines have steel lattice towers, which require less maintenance. Categorized as having low potential impacts, Lines 951, 906, 912, 904, and 911, had Activity Indices of 3.6, 3.1, 1.7, 1.4, and 1.2, respectively. These lines require limited vegetation clearing, and maintenance needs are more limited for these lines than for others. Site-specific problems are likely to be present on all of these lines, but the Risk Index presented below more appropriately addresses those impacts.

Vegetation that is growing on or adjacent to a road or tower survey unit has a higher risk of being impacted by O&M activities than does vegetation farther from these sites. Also, higher levels of O&M activity could result in a higher potential for vegetation to be disturbed. Therefore, because we used such factors to determine the Risk Index, a higher Risk Index level should equate to a higher potential for disturbance. One hundred fifty-five survey units were classified as having a low risk for disturbance; 340 survey units, as having moderately low risk; 178 survey units, moderate risk; and 37 survey units, highest risk (Table 73).

The distribution of Risk Index levels by transmission line indicates that survey units with moderate or highest ratings are more concentrated on Lines 903, 907, 908, 910, and 911 (Table 74). Of the 13 survey units on Line 910, nine had a moderate Risk Index level and one had a highest rating. Line 908 has 19 survey units, but the Risk Index level for all units are either moderate or highest. Eighty-one percent of Line 907’s survey units were in the moderate and highest levels; 43% of Line 903’s units were rated moderate and highest. Thirty-four percent of survey units on Line 911 were at the moderate or highest level. All other lines had less than 25% of their survey units in the two highest Risk Index levels. The topography in these units is more

Hells Canyon Complex Page 77 Effects of Road and Transmission Line Idaho Power Company prone to road-related erosion or slumping problems, a condition that likely accounts for the higher Risk Index levels.

4.4.2.2. Effects on Rare Plants We analyzed survey units in each Risk Index class for rare plant occurrences (Table 73). Twelve survey units in the low risk class had 13 occurrences of rare plants, consisting of 3 different species or subspecies. Of those 12 survey units, 1 survey unit had 2 rare plant species. The moderately low risk class had 20 survey units containing 21 occurrences of rare plants, consisting of 8 species or subspecies. Of the 20 survey units, only 1 had 2 species or subspecies present. Sixteen moderate risk survey units contained 17 occurrences of rare plants, consisting of 4 species or subspecies. Of those 16 survey units, 1 had 2 species or subspecies present. Only 1 highest risk survey unit contained rare plants—two species.

Survey units rated with Risk Indices of low (to moderately low are considered to have a low risk of potential impacts from O&M activities; therefore, only rare plant occurrences on survey units with a Risk Index of moderate or highest are considered here. The Risk Index categories are a function of the Activity Index and road-related parameters, such as road use and road-related water erosion (see section 3.4.2). We located 17 rare plant species occurrences on survey units with a moderate Risk Index and 2 occurrences on survey units with a highest Risk Index (Table 73). All occurrences were either within the roadway or within the 50-m buffer zone. None occurred outside the buffer zone.

Astragalus atratus var. inseptus Five of the 19 occurrences of Astragalus atratus var. inseptus (mourning milkvetch) that we located were in units having potential O&M impacts (Table 75). Occurrences 9, 11, 14, 17, and 18 (Table 10) were located in survey units with a moderate Risk Index. The survey units with these 5 occurrences were all located on Line 912, which falls within the low category for the Activity Index (Table 72). Road use, water erosion, and disturbance from service road construction all averaged moderate on corresponding survey units (Table 11). No occurrences of Astragalus atratus var. inseptus were located in units with a highest Risk Index category.

Astragalus atratus var. owyheensis One of the 4 occurrences of Astragalus atratus var. owyheensis (Owyhee milkvetch) that we located was in a survey unit with a moderate Risk Index category (Table 75). Occurrence 1 (Table 12) was rare in the buffer zone and absent in both the roadway and the area beyond the buffer zone in survey unit 903-030-A1. The survey unit occurs on Line 903, which falls within the moderately low Activity Index category (Table 72). Water erosion was rated slight, while road use and disturbance from service road construction were both rated moderate on the survey unit (Table 13). No occurrences of Astragalus atratus var. owyheensis were located in units with a highest Risk Index category.

Bolandra oregana We located the 1 occurrence of Bolandra oregana (Oregon bolandra) in a survey unit with a highest Risk Index category (Table 75). Occurrence 1 (Table 16) was locally rare in the buffer zone and absent in both the roadway and the area beyond the buffer zone in survey unit

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908-147-A1. The survey unit occurs on Line 908, which falls within the moderate Activity Index category (Table 72). Road use, water erosion, and disturbance from service road construction were all rated moderate on the survey unit (Table 17).

Carex backii Six of the 10 occurrences of Carex backii (Back’s sedge) were in units with potential O&M impacts (Table 75). Occurrence 9 (Table 18) was located in a survey unit with a highest Risk Index category. The survey unit occurs on Line 907, which falls within the moderate Activity Index category (Table 72). Water erosion was not detected, while road use and disturbance from service road construction were both rated moderate on the survey unit (Table 19). Occurrences 1, 3, 6, 8, and 10 (Table 19) were in survey units with a moderate Risk Index category. Survey units containing these 5 occurrences occur on Lines 907, 908, or 910, all of which fall within the moderate Activity Index category (Table 72). Disturbance from service-road construction averaged moderate, road use averaged slight to moderate, and water erosion averaged slight on corresponding survey units (Table 19).

Stylocline filaginea Five of the 13 occurrences of Stylocline filaginaea (hooked stylocline) were in units with potential O&M impacts (Table 75). Occurrences 1, 10, 11, 12, and 13 (Table 24) were located in survey units with a moderate Risk Index category. The survey units containing these 5 occurrences occur on Lines 904, 911, or 912, all of which fall within the low Activity Index category (Table 72). Water erosion averaged moderate to high, disturbance from service-road construction averaged moderate, and road use averaged slight to moderate on corresponding survey units (Table 25). No occurrences of Stylocline filaginaea were located in units with a highest Risk Index category.

4.4.2.3. Effects on Noxious Weeds Noxious weeds were widespread throughout the study area, resulting in a high number of weed occurrences in all Risk Index classes—103 occurrences in the low risk class, 401 in the moderately low risk class, 360 in the moderate risk class, and 133 in the highest risk class (Table 73). Numerous survey units in all Risk Index classes had multiple weed species present on them (Table 73), with up to 7 weed species present on some survey units. We found a positive correlation between the number of weed occurrences on a survey unit and the Risk Index class: the average number of weed occurrences per survey unit increases with increasing Risk Index class (Table 73). The low risk class survey units have a mean of 0.6 weed occurrences per survey unit. Survey units categorized as moderately low risk have a mean of 1.2 occurrences per survey unit. Moderate risk survey units have a mean of 2.0 weed occurrences per survey unit. And highest risk survey units have a mean of 3.6 weed occurrences per survey unit.

The mean number of noxious weed occurrences per survey unit on each transmission line is indicated in the following table. Lines 908 and 905 contained the greatest average number of weed occurrences per survey unit (n = 1.7).

Line Number: 905 908 913 903 904 910 911 907 912 906 951 Mean no. weed occurrences/survey unit: 1.7 1.7 1.4 1.3 1.3 1.1 0.9 0.6 0.4 0.3 0.1

Hells Canyon Complex Page 79 Effects of Road and Transmission Line Idaho Power Company

4.4.3. Rights-of-Way Clearance Studies

4.4.3.1. Forest Region Cleared Rights-of-Way Areas Four transmission lines (907, 908, 910, and 913) pass through about 50 km of the WWNF (Figure 4, panel 4). Forest cover types in this region include Pseudotsuga menziesii, Abies grandis, Abies concolor, and Pinus ponderosa. Tree stand patterns in this part of the WWNF are variable, ranging from dense canopies to stringers of trees on the steeper slopes. Forest openings are very common and typically either montane shrubfields or perennial grasslands. Most of the transmission lines on the WWNF are within the HCNRA. Timber harvest on the HCNRA in the vicinity of the lines is limited to portions of Line 907. Timber harvest outside the HCNRA, but still within the region, occurs along all of Line 913.

The Imnaha River is a predominate feature of the area. It flows northward from the for 124 km to the Snake River. Line 907 follows the river closely for about 7 km within the WWNF. Line 908 follows the river for the line’s entire length (39 km) where the river is mostly bordered by private land. River edge cover types in the forested region where the lines are present are dominated by riverine riparian and wet and dry meadows. Effects of the ROW on the riparian vegetation of the river are discussed below in section 4.4.3.3.

Of the 50 km of ROW on the WWNF, about 27 km have the same cover types as adjacent areas outside the ROW. These same cover types include 7 km of forest cover type where the lines do not affect forest stands because the lines are high enough above the trees to avoid interference. In the remaining 20 km, the cover types are shrub or grass types that require no or minimal vegetation removal.

Twenty-three kilometers of ROW have cover types different from adjacent areas. About 17 km appear to have changed from a tree cover type to a shrub or grass cover type, and about 7 km have changed from non-forested to other non-forested types (Table 76). Some of this latter change may be due to natural succession, and some is probably due to suppression of tall vegetation by IPC. The most common conversion of forested to non-forested cover type has been to montane shrub (12.6 km). The remaining conversion is almost all dry meadow (2.6 km) or alpine shrub (1.6 km) (Table 76). Some of the shrub areas were probably understory areas prior to tree removal. A small amount of riparian (149 m) cover type appears to have been either created from tree removal or exposed after tree removal.

When habitat is fragmented (i.e., vegetation patches are broken into smaller pieces), total habitat area, as well as patch size and complexity, is reduced. Although the impact of fragmentation is usually analyzed for wildlife on a species-specific basis, it is important to identify the processes causing fragmentation. In forested environments, cleared ROW that are typically 30 m wide may cause habitat fragmentation. The WWNF in which the transmission-line corridor is situated is naturally fragmented; that is, the forest cover is not contiguous, but patchy due to topography, soils, and aspect. Large, homogeneous forest stands are rare or nonexistent in the corridor area. Therefore, although line clearing affects site-specific habitat conditions, it is not likely to cause landscape-level fragmentation. The effect of fragmentation on wildlife is investigated in Dumas and Carpenter (2002). However, because the forested environment that is crossed by the

Page 80 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line transmission line is naturally patchy, the transmission line’s fragmentation effects on the forested environment are likely to be small, if existing at all.

4.4.3.2. Snag, Large Tree, and Log Characteristics Adjacent to Rights-of-Way We surveyed snags, large trees, and logs on 40 transects, which totaled 12 ha of sampling area. The transects were stratified evenly into the hazard zone and the control zone. Plot size analysis showed that the 30-m transect width we used was optimal for the forest stands we surveyed. Pseudotsuga menziesii was the most common species encountered as snags, large trees, and logs; this species made up 31 to 48% of each type. Pinus ponderosa and Abies grandis evenly made up most of the remainder of the species with only a few Larix occidentalis, Pinus contorta, and Picea engelmanni.

We counted twice as many snags in the control zone as in the hazard zone (Table 77). Twenty- one snags were present on 50% of the hazard zone transects, while 42 snags were present on 65% of the control transects. Although snag density was greater in the control zone than in the hazard zone (7.0 vs. 3.5 snags/ha, respectively) (Table 77), the variance in both samples was high. The difference in the means was not statistically significant when we used the Student’s t-test (P = 0.15). The mean dbh and height of snags were similar between the two sample areas (Table 77). Sample size analysis indicated at least 38 hazard zone transects and 70 control transects would be needed to return snag density estimates to within 20% of the true mean 90% of the time. Our field reconnaissance indicated that forest habitat adjacent to the ROW is limited and that obtaining the recommended number of samples may not be possible.

Additional data collected on the snags included structural condition and foraging and cavity use. Structural condition was similar between the hazard zone and control: class 1 (recently dead, 31 vs. 33%), class 2 (dead several years, 41 vs. 43%), and class 3 (advanced decay, 24 vs. 29%). We recorded avian nest cavities and foraging activity for each snag encountered. Nineteen of 21 snags in the hazard zone and 29 of 42 snags in the control zone had foraging sign. Nine snags in the hazard zone and 17 snags in the control zone had nesting cavities.

Unlike for snags, distribution of large trees in the control and hazard zones was similar. One hundred thirty-three trees were present on 19 of the hazard zone transects, and 140 trees were on 17 control transects. Densities of large trees did not differ significantly in the two areas (22.2/ha vs. 23.3/ha) (Table 77). Likewise, the mean size in dbh and height was almost identical in the two zones (Table 77). Sample size analysis indicated only one additional transect in each zone would be needed to return large tree density estimates to within 20% of the true mean 90% of the time. All large trees sampled were structurally sound.

Sampled logs had similar characteristics in the control and hazard zones. We counted 154 logs on 95% of hazard zone transects and 166 logs on 90% of control transects. There were 24 logs per hectare (24/ha) in the hazard zone and 26/ha in the control zone (Table 77). Mean length of logs was 10 m for both areas. Log presence was more variable in the hazard zone, and sample size analysis indicated 10 additional transects would be needed for density estimates within 20% of the true mean 90% of the time. In the hazard zone, 58% of the logs were natural falls and 42% were cut. In the control area, 66% were natural falls and 34% were cut.

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Snags are important structures in forest ecosystems (Harrod et al. 1998). Snags provide wildlife habitat to many species of primary and secondary cavity nesters (Thomas 1979). Dumas and Carpenter (2002) discuss the effects of the reduction of snags on wildlife. The HCNRA management plan (USFS 1999) recommends snag densities be maintained at the 100% population level for primary cavity excavators. The recommended levels are based on guidelines in Thomas (1979) and on more recent work done in the interior Columbia River basin (Bull and Holthausen 1993, Bull et al. 1997). Recommended snag densities depend on the forest cover type and the bird species being managed. For northeastern Oregon, in closed-canopy, mixed conifer forests, pileated woodpeckers (Dryocopus pileatus) were supported in areas of 1.4 snags/ha (> 25.4 cm) (Bull et al. 1997). On the Payette National Forest, mixed conifer snag densities of 1 to 3.6/ha are recommended (Bull et al. 1997). The Lewis’ woodpecker (Melanerpes lewis) and white-headed woodpecker (Picoides albolarvatus) in ponderosa pine forests require snag densities of 2.5/ha and 5.6/ha, respectively, according to Thomas (1979). All three woodpecker species are IPC species of special concern, and the pileated woodpecker is a forest indicator species. Our results indicate snag densities may be adequate in the hazard zone (mean 3.5/ha) for some species.

4.4.3.3. Riparian Characteristics in Rights-of-Way Table 78 details line-by-line estimates (in meters) of four types of riparian habitat present on public land portions of the transmission lines. We classified riparian habitat into riverine, deciduous tree, shrub, and wet meadow types. Ninety-four locations totaled approximately 9.7 km of riparian habitat, which were made up of 4.6 km of riverine, 3.3 km of shrub, 1.1 km of wet meadow, and 0.7 km of deciduous tree habitat (Table 78). Riverine habitat tends to cover larger areas than the other three types as it includes conifer species as well as shrubs and it can extend away from the water source. The 9.7 km of riparian habitat was 1.7% of the 568 km of lines on public land. No riparian habitat was mapped for Lines 951 and 952 on public lands. The distances presented should be considered maximum estimates because in a few cases our mapping included entire tower spans when the actual extent of riparian present was probably only a small portion of the span. Lines 907 and 911 have the most riparian habitat, with over 3 km each. Line 907 riparian habitat is present primarily along the Imnaha River (see later discussion in this section). Line 911 riparian habitat occurs at 15 locations; this line is the one most likely to be over-represented in our estimates.

Of the 9.7 km of riparian habitat, we estimated that 1.5 km (15%) requires vegetation management in the form of periodic trimming or removal (Table 78). Five of the 12 lines with riparian habitat require such management. The 1.5 km is probably an overestimate, and the actual amount to be managed is likely to be less. Over half of the vegetation management occurs on Line 907 discussed below. For the remaining riparian habitat, sufficient space between the conductors and the vegetation prevents the vegetation from interfering with conductors.

The Imnaha River corridor on the WWNF has the most substantial and contiguous riparian habitat of the project area. The river is designated as a National Wild and Scenic River that flows 124 km (77 mi) from the Eagle Cap Wilderness to the Snake River (Figure 4, panel 4). The 45-km river section adjacent to Transmission Lines 907 and 908 is designated as recreational. Beginning near Blackhorse Campground, Line 907 parallels the Imnaha River for 7 km on public land, crossing it 13 times. The line then parallels the river on private land for 0.5 km. As

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Line 907 ends, Line 908 begins and parallels the river for 38 km, crossing it 8 times. Thirty-two kilometers of this line are on public land. The WWNF cover type map shows a 115-ha, 14-km-long polygon of riverine riparian habitat in the vicinity of Line 907 and the first 5 km of Line 908. Public land riverine riparian is limited to Line 907, so we focused our discussion of riparian vegetation management on this line.

In the Line 907 ROW between towers 104 and 129, there are 19 ha of riverine riparian and 3 ha of river surface. We trim or remove 0.6 ha (1.5 acre) of riparian habitat on bank edges and 3.7 ha of montane shrub, conifer, and dry meadow habitat away from the river’s edge. The remaining 14.7 ha of ROW do not appear to require vegetation management because of naturally low vegetation height. The 0.6 ha of bank edge that is trimmed or cut is scattered among 24 locations at 13 river crossings; areas average 15 by 15 m in area. Species managed include Alnus species, Crataegus douglasii, and Pseudotsuga menziesii.

5. CONCLUSIONS / MANAGEMENT IMPLICATIONS

5.1. Impacts on General Vegetation

5.1.1. Rights-of-Way Effects on Landscape-Level Vegetation Patterns

There is little evidence that the transmission line and service-road ROW affect vegetation composition or pattern in most regions of the study area. Vegetation in the Snake River Plain, Snake River Plateau, Payette Valley, and Idaho Canyon/Mountain regions has departed significantly from historical composition levels and patterns and continues to be fragmented by landscape-level processes (Quigley and Arbelbide 1997). Our survey results for disturbances associated with the transmission-line and service-road ROW reinforce this notion. Agriculture is a dominant footprint on the southern Idaho landscape; it accounted for 37% of the vegetation in the Snake River Plain region (Table 6). Fire and livestock grazing were ubiquitous in most of the regions (Tables 44 and 46). Resulting changes in vegetation composition and pattern clearly reflect fragmented ecosystems (Knick and Rotenberry 1995). The role of IPC in the fragmentation process of these shrub-steppe ecosystems is limited. However, IPC can help reduce further fragmentation of these ecosystems by maintaining and repairing the transmission lines and thus reducing potential fire ignition associated with faults in the electrical system.

Although the effects of the ROW were not fully analyzed for the Oregon Plateau and Canyon and the Oregon Upper Plateau regions, we suggest that there are negligible impacts to these shrub-steppe habitats, as evidenced by the lack of impacts to the shrub-steppe habitats discussed above. We observed improved vegetation conditions in these zones when compared with the shrub-steppe zones in Idaho. High-quality sagebrush and native bunchgrass communities were more prevalent in these zones. Invasive annual grass communities were present, but to a lesser degree than is seen to the east.

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In the WWNF region, our studies indicate that the ROW are having an effect on vegetation patterns. Clearing of tall vegetation from below the transmission lines has, in essence, resulted in strips of clear-cuts within forest stands. About 17 km of ROW are managed to eliminate tall vegetation from interfering with the transmission lines. However, the effects of this clearing appear only locally and not on the landscape scale. Where the ROW occur, the nature of the environment has resulted in naturally fragmented patches of denser forest canopy mixed with open forest savannah and shrublands or grasslands. Although vegetation clearing has a localized impact on the composition and pattern of vegetation within the ROW, it has minimal impacts on the adjacent communities and thus is probably not causing fragmentation. Historically, fire played a more prominent role in the ecology of these forests, resulting in less dense, smaller patches of earlier successional species (Quigley and Arbelbide 1997, Heyerdahl et al. 2001).

5.1.2. Operation and Maintenance Effects on Vegetation

O&M activities, including ROW vegetation clearing, have only site-specific impacts in the regions outside of the WWNF, including the areas of Lines 904 and 911 on the Payette National Forest. ROW clearing occurs on about 23 km of ROW. The greatest potential for impacts of IPC O&M activities associated with HCC transmission lines are on riparian vegetation associated with the Imnaha River and on the resources of snags, large woody materials, and large trees associated with the ROW. These potential impacts are discussed in more detail in this section.

5.1.2.1 Riparian Rights-of-Way Clearing Transmission Lines 907 and 908 parallel and cross the Imnaha River on public land (WWNF) for approximately 39 km. Within this area, vegetation clearing is required on about 1.3 km, all of which occurs on Line 907. Along that length, vegetation clearing occurs on approximately 4.3 ha (10.6 acres), of which 0.6 ha (1.5 acres) is riparian vegetation. These riparian patches tend to be small and numerous; 24 different patches are managed for tall-growing vegetation. In addition to ROW clearing, areas of Lines 907 and 908 receive heavy use because of grazing (Table 46) and recreational activities, and they are influenced by land use activities on adjacent private property. Line 907’s location along the Imnaha River coincides with the south-to-north transition from closed-canopy, forested riparian communities to more open, savannah-like riparian communities. If not for this transition, ROW clearing would have a much greater impact on the riparian and riverine plant communities in this area. ROW clearing has no impact on riparian communities on public land along Line 908. Line 908 intercepts public land (WWNF) away from the river on more upland landscapes.

IPC could reduce the impact of vegetation clearing along the Imnaha River by developing a more detailed vegetation management plan. Such a plan could promote a more frequent, less intensive clearing cycle, which would allow for riparian vegetation to develop more beneath the lines, while still not representing a threat to system reliability or safety. Growth rates of vegetation communities below Line 907 could be studied and mapped in relation to conductor sag levels to provide managers with better spatial information on where and when clearing is likely to be needed. To mitigate impacts to riparian patches that must be cleared, trees and other tall-growing vegetation could be promoted or planted in riparian areas that are deficient in such resources and that are not in conflict with transmission lines.

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5.1.2.2 Snags, Large Woody Debris, and Large Trees Although the results of snag inventories are variable due to low sample sizes, little difference in the structure and the composition of the forest was noted between the hazard zone or the area outside the hazard zone. Results from section 4.4.3.1 indicated that 17 km of non-forest type ROW have forested cover types adjacent to areas where occasional hazard tree removal is likely. If we conservatively assume that the hazard tree zone extends 30 m on either side of this area, up to 100 ha (247 acres) of habitat may have reduced snag densities and 50 ha within the cleared zone may have had all trees removed. This area is extremely small compared with the 251,436 ha (621,311 acres) of the HCNRA or the 968,215 ha (2,392,508 acres) of the WWNF. Snags that are felled in the hazard zone are not removed and will continue to perform important ecosystem functions (Bull et al. 1997). The absence of snags in the cleared zone may impact wildlife species by limiting cavity nesting and foraging opportunities. However, it is unlikely that this reduction causes fragmentation or other impacts to populations of cavity-dependent species in the vicinity of the ROW. Given that openings in forest stands created by the ROW are not any larger than opening that can be found throughout the forest, there should be no impediment to the distribution of snag-dependent species that populate these forests. Based on our survey, ample snag resources are available adjacent to the cleared zones.

The HCNRA land management plan (USFS 1999), which covers all the lines except for a small part of Line 913, indicates that the HCNRA provides large amounts of unharvested forest, much of it with high densities of snag and downed woody habitat. The current regional forester’s direction in amendment 2 is to maintain snag densities at the 100% population level for primary excavators. No data is provided on what the levels are, but in these areas, populations of primary excavators are assumed to be near the 100%, or natural, population levels. The WWNF land and resource management plan (USDA 1990) refers to maintaining snags at 40 to 60% of the optimum habitat level for cavity nesters. Lines 907, 908, and 910 and most of Line 913 are in management zones 10 and 11. In management zone 10, there is no timber harvest, and the plan assumes that natural tree mortality will provide snag habitat for snag-dependent species at 100% of potential. In management zone 11, the management direction is to manage snags of all sizes at a level that provides habitat for snag-dependant species at 60% of optimum. No explanation is provided on the optimum. Some of Line 913 is in management zone 1, where timber production is emphasized. Snag management direction states that snags 12 to 18 inches in diameter will usually exceed 40% of the optimum habitat for cavity nesters through natural mortality in managed stands. Some specific recommendations for old-growth areas are to manage for at least one 21-inch dbh snag per acre and 3 logs per acre (> 9 inches in diameter). For pileated woodpeckers, management direction is to maintain at least 2 hard snags of 10 inches dbh or larger per acre. We found in our study zones 1.4 snags per acre with 22-inch mean dbh in the hazard zone and 2.8 snags per acre of 20-inch dbh in the control zone. We found 9.7 logs per acre in the hazard zone and 10.5 in the control zone. Therefore, the number of snags and logs in the hazard zone appears to be adequate for current management direction. There was no apparent difference in large tree (> 50-cm dbh) resources between the hazard zone and the control area.

Because of a lack of large tree resources within the cleared ROW, there is no direct recruitment of snags and large woody material. An IPC management objective is to keep the ROW cleared of trees and snags that are hazardous to the safety and to the reliability of the transmission lines. Therefore, these low-wood conditions will persist in the future. IPC can reduce potential impacts

Hells Canyon Complex Page 85 Effects of Road and Transmission Line Idaho Power Company to these wood resources within the hazard zone by implementing a timely hazard tree removal program to remove only those trees and snags having a high likelihood of interfering with the transmission lines. By leaving cut trees and snags on site, recruitment of large, downed wood within the hazard zone should be adequate.

5.2. Impacts on Rare Plants

IPC surveys located 62 occurrences of 9 rare plant species along service roads or tower sites associated with HCC transmission lines. No federally listed threatened or endangered plant species were found. For each rare species encountered, phenologic, demographic, and topographic characteristics were recorded, along with information regarding associated plant species, adjacent cover types, and possible habitat threats. We did not directly study disturbance responses of rare species. However, we can make some estimation about disturbance impacts based on habitat characteristics of individual species and knowledge of general threats posed by individual disturbance types.

5.2.1. Rare Plant Species

Conservation of rare plants in the study area may involve several measures, depending on the natural history of the species and our knowledge of the dynamics of the occurrences under consideration and of threats to species occurrences. Protecting populations from physical disturbance, controlling encroaching weed species, and monitoring species occurrences are a few of the many conservation and enhancement measures that may be taken. Conservation concerns for each rare plant species are considered in this section. See Appendix 6 for an explanation of species status designations.

5.2.1.1. Allium aaseae We located 3 occurrences of Allium aaseae in the Boise Foothills, along Line 904. Two occurrences were located within the 50-m road buffer zone, and 1 occurrence lay within the service-road ROW. These occurrences were located in the eastern half of the species’ distribution range, where occurrences are vulnerable to urban development and private land management (Mancuso 1995b). Two of the 3 occurrences are on public land, and 1 occurrence spans a property line between private and public land. Rare plant observation forms cite livestock grazing, recreational trail use, urbanization, and exotic species invasion as the most likely threats to the occurrences. These findings are not surprising, as Mancuso lists livestock grazing, urban/suburbanization, sand mining, and recreational use as the major land uses impacting occurrences of Allium aaseae since European settlement.

Conservation Concerns and Recommendations All 3 occurrences of Allium aaseae located by IPC are threatened by livestock grazing. Mancuso (1995b) states that, because of the early phenology of the species, livestock grazing is not likely to result in the direct loss of Allium aaseae habitat; however, he notes that indirect effects of livestock grazing (i.e., increase of invasions by exotic species due to disturbance) contribute to habitat decline. Regulation of grazing intensity in the general area is recommended to ensure that

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Allium aaseae habitat is not adversely affected. In addition to livestock grazing, exotic species invasions pose threats to all 3 occurrences. In particular, infestations of Bromus tectorum and Chondrilla juncea are widespread throughout the area. Some means of containment or control of these species is recommended to curb encroachment upon Allium aaseae occurrences and to promote continued existence of healthy stand structure. Disturbance from road-maintenance activities should also be considered because such activities can promote the spread of noxious weeds and may also negatively affect the 1 occurrence of Allium aaseae that lies within the service-road ROW. Disturbance from urbanization and recreational use strains conservation efforts. As the population of Boise increases, recreational use of the Boise Foothills will undoubtedly increase. Effective means of regulating recreational use of public lands are lacking. Nonetheless, the BLM is actively implementing measures to conserve Allium aaseae, and other public organizations, including the Boise National Forest, Ada County, and Boise City, have contributed funds for additional survey work in the Boise Foothills (Mancuso 1995b).

5.2.1.2. Astragalus species We located occurrences of three rare Astragalus species. In the southeastern portion of the study area, 19 occurrences of Astragalus atratus var. inseptus were located along Lines 906 and 912, and 2 possible (not yet confirmed) occurrences of Astragalus purshii var. ophiogenes were located along Line 912. In Oregon, 4 occurrences of Astragalus atratus var. owyheensis were located along Line 903. Livestock grazing is extensive in most of the area along Lines 906 and 912. The area is also heavily infested with Bromus tectorum and Taeniatherum caput-medusae. These two weedy grass species are not only very aggressive invaders, but they are also known to alter fire frequencies and intensities in sagebrush communities in southern Idaho (ISDA 1999). Intensive livestock grazing, altered fire regimes, and exotic species invasions, therefore, pose the most likely threats to Astragalus species occurrences on Lines 906 and 912. Rare plant observations forms for Astragalus atratus var. owyheensis in Oregon indicate that all occurrences lie within good-quality Artemisia tridentata /Poa secunda habitat, with slight livestock disturbance and potential invasion from nearby occurrences of Cardaria draba.

Conservation Concerns and Recommendations Livestock grazing was reported as an imminent threat to Astragalus species occurrences along Lines 906 and 912, where grazing was rated as extreme around occurrences of Astragalus purshii var. ophiogenes and moderate around occurrences of Astragalus atratus var. inseptus. Livestock grazing, rated as slight around occurrences of Astragalus atratus var. owyheensis along Line 903, was noted as a potential, but not imminent threat. Regulation of grazing intensity around Astragalus species along Lines 906 and 912 is recommended to ensure that species habitat is not adversely affected. Exotic species invasions pose major threats to all Astragalus species occurrences. Bromus tectorum and Taeniatherum caput-medusae dominate the understory in much of the area surrounding Astragalus species occurrences along Lines 906 and 912. In addition, Chondrilla juncea was often found in units associated with these occurrences. The Astragalus species occurrences along Line 903 were observed in good-quality Artemisia tridentata habitat, but were located within units having severe Cardaria draba infestations. Some means of containing or controlling exotic species occurring in close proximity to rare Astragalus species occurrences is recommended to curb encroachment and to promote continued existence of healthy stand structure. Management of Bromus tectorum and Taeniatherum caput-

Hells Canyon Complex Page 87 Effects of Road and Transmission Line Idaho Power Company medusae is particularly important along Lines 906 and 912 as both species encourage fire events. Rare plant observation forms for all Astragalus species occurrences along Lines 906 and 912 report fire disturbance as an imminent threat. Disturbance from road-maintenance activities should also be considered as such activities can promote the spread of noxious weeds and may also negatively effect the 14 occurrences of Astragalus species that lie within service-road ROW (Table 7).

5.2.1.3. Bolandra oregana We located 1 occurrence of Bolandra oregana along Line 908 in Oregon. Intensity of livestock disturbance was rated high in the survey unit associated with the occurrence, while disturbance from service road construction and water erosion was each rated as moderate. Seven species of noxious weeds were present in the unit, but no other disturbance was recorded. The occurrence was found growing in the cracks of exposed basalt under a small waterfall. Because of this location, livestock and service road construction are not likely threats. Also, the occurrence occupies such a narrow niche environmentally that invasion by other species is unlikely. Finally, because the water erosion disturbance recorded for the associated unit pertains to erosion on the service-road ROW, water erosion does not pose a threat to the occurrence. The absence of perceived threats to the Bolandra oregana occurrence suggests that no conservation measures are needed at this time.

5.2.1.4. Carex backii We located 10 new occurrences of Carex backii in Oregon, with 2 occurrences on Line 908, 7 occurrences on Line 907, and 1 occurrence on Line 910. Disturbance from livestock was an imminent threat: numerous cattle trails and significant trampling were present in the vicinity of Carex backii occurrences. Noxious weeds were widespread and generally locally frequent to locally abundant throughout the majority of survey units with Carex backii occurrences. Service road construction was cited as a potential threat to 1 occurrence.

Conservation Concerns and Recommendations Livestock grazing and timber harvest reportedly pose the most imminent threat to occurrences of Carex backii in Oregon. Timber harvest was not noted as a major threat to Carex backii occurrences located by IPC; however, livestock disturbance was reported as an imminent threat to 4 occurrences. On units associated with these 4 occurrences, intensity of grazing was rated as high on 2 of the occurrences, moderate on 1, and slight on 1. Regulation of grazing intensity around noted occurrences of Carex backii is recommended to ensure that species habitat is not adversely affected. Although exotic species invasion was not noted as a potential threat to Carex backii occurrences, the abundance of exotic species in units with Carex backii indicates that future invasion may be a potential threat. Therefore, an evaluation of the proximity of invasive species and some means of containing or controlling those occurring near rare Carex backii occurrences are recommended to curb encroachment and to promote continued existence of healthy stand structure. Disturbance from road-maintenance activities should also be considered as such activities can promote the spread of noxious weeds and may also negatively affect the 6 occurrences of Carex backii that lie within service-road ROW (Table 7).

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5.2.1.5. Mimulus clivicola We located 1 new occurrence of Mimulus clivicola on Line 907 in Oregon. Disturbances by big game, livestock grazing, and logging pose potential, but not imminent, threats to the occurrence. Three species of noxious weeds were present in the survey unit associated with the occurrence; however, exotic species invasion was not noted as a threat to the occurrence. The apparent stability of the Mimulus clivicola occurrence suggests that no conservation measures are needed at this time; however, the occurrence should continue to be monitored.

5.2.1.6. Rubus bartonianus We located 10 new occurrences of Rubus bartonianus in the Payette National Forest along Line 945. Disturbance on units associated with Rubus bartonianus occurrences was relatively minimal. Eight species of noxious weeds were present in survey units associated with the occurrences, but no noxious weeds were noted to occur within those occurrences. Johnson and Mattson (1978) described the Hells Canyon Reservoir occurrences as widespread between Hells Canyon Dam and Kinney Creek, adding that the occurrences successfully withstood disturbance from dam construction. Moseley (1989) described occurrences of Rubus bartonianus in Hells Canyon Reservoir as secure, with no major threats. He recommended, however, that the species be ranked as sensitive in Idaho based on its narrow range and on potential threats to some of the occurrences. IPC surveys suggest that Rubus bartonianus occurrences remain stable in the study area. As a result, no conservation measures are recommended at this time; however, the occurrences should continue to be monitored.

5.2.1.7. Stylocline filaginea We located 13 new occurrences of Stylocline filaginea in Idaho along Lines 904, 906, 911, and 912. Livestock grazing, fire, and exotic species invasion (i.e., Bromus tectorum, Taeniatherum caput-medusae, and Chondrilla juncea) impacts were ubiquitous and represent threats to the occurrences. In spite of these threats, Stylocline filaginea has recently been observed to be widespread and relatively secure in Idaho. Nonetheless, conservation concerns are considered here.

Conservation Concerns and Recommendations The environmental conditions for occurrences of Stylocline filaginea located along Lines 904, 906, 911, and 912 are very similar to those for the Astragalus species located along Lines 906 and 912 (see section 5.9.1.2). Therefore, conservation strategies for Stylocline filaginea are similar to those for Astragalus species. Regulation of grazing intensity around Stylocline filaginea occurrences is recommended to ensure that species habitat is not adversely affected. In addition, some means of containing or controlling exotic species occurring in close proximity to rare Stylocline filaginea occurrences is recommended to curb encroachment and to promote continued existence of healthy stand structure. Management of Bromus tectorum and Taeniatherum caput-medusae may be particularly useful in limiting fire disturbance. Disturbance from road-maintenance activities should also be considered as such activities can promote the spread of noxious weeds and may also negatively affect the 9 occurrences of Stylocline filaginea that lie within service-road ROW (Table 7). If Stylocline filaginea is moved or dropped from the

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INPS monitor list in the near future, the above conservation measures will not be necessary. In any case, the occurrences should continue to be monitored.

Five of the 13 occurrences of Stylocline filaginea were located in units with potential O&M impacts (Table 75).

5.2.2. Management Implications for Rare Plants

Within the study area, livestock grazing and fire disturbance pose the most imminent threats to rare plant occurrences. Livestock disturbance was listed as an imminent threat to the occurrences of Carex backii that were located during surveys, as well as to those occurrences already known to exist in the study area. Livestock was also considered a possible threat to occurrences of Allium aaseae, Astragalus atratus var. inseptus, Astragalus purshii var. ophiogenes, and Stylocline filaginea. Fire disturbance was believed to pose a threat to occurrences of Astragalus atratus var. inseptus and Stylocline filaginea in portions of the study area southeast of Brownlee Dam. In addition to livestock and fire disturbance, big game disturbance was noted to pose a slight threat to one occurrence of Astragalus atratus var. inseptus and a potential threat to one occurrence of Mimulus clivicola. Disturbances from road use, OHV use, service road construction, and non-project road use were noted to pose potential threats to one occurrence of Carex backii. All other disturbance types were considered to have little negative impact to rare plant occurrences.

Management Recommendations IPC has no jurisdiction over livestock grazing in the study area, but controlling grazing intensity would have the most benefit to several occurrences of rare plants in the vicinity of several transmission lines. Implementation of such grazing management practices is at the discretion of the federal land management agencies in these areas.

In Oregon, regulation of grazing intensity for occurrences of Astragalus atratus var. owyheensis along Line 903 and for occurrences of Carex backii along Lines 907, 908, and 910 would reduce negative impacts. In Idaho, control of grazing intensity around Allium aaseae occurrences on Line 904, Astragalus species occurrences along Lines 906 and 912, and Stylocline filaginea occurrences along Lines 904, 906, 911, and 912 would be warranted.

Noxious weeds were present on 77% of units surveyed and can pose potential threats to rare plant occurrences in the study area. In particular, three noxious weeds, Cardaria draba, Chondrilla juncea, and Taeniatherum caput-medusae, and the weedy annual grass, Bromus tectorum, are noted as the disturbances most likely to negatively impact rare plant occurrences. In Oregon, some means of containing or controlling occurrences of Cardaria draba is recommended to curb encroachment into Astragalus atratus var. owyheensis occurrences along Line 903. In Idaho, similar measures for containing or controlling Chondrilla juncea, Bromus tectorum, and Taeniatherum caput-medusae are recommended around Allium aaseae occurrences on Line 904, Astragalus species occurrences along Lines 906 and 912, and Stylocline filaginea occurrences along Lines 904, 906, 911, and 912. Management of Bromus tectorum and Taeniatherum caput-medusae along lines southeast of Brownlee Dam (904, 906, 911, and 912) may be particularly useful in limiting fire disturbance.

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In general, we recommend working cooperatively with federal land management agencies to protect rare plant sites threatened by disturbance activities. Specific actions to reduce disturbance from O&M activities should be implemented. O&M activities can promote the spread of noxious weeds, which may negatively impact the 38 rare plant occurrences that lie within service-road ROW (Table 7). Rare plant occurrences that lie within survey units rated as having O&M Risk Index categories of moderate or highest are considered to be at risk for impacts from O&M activities (see Section 4.4.2.1). Sixteen rare plant occurrences were located in survey units having a moderate Risk Index category, and 2 occurrences were located on survey units having highest Risk Index category (Table 73). Specific protection activities should be adopted to minimize negative impacts from O&M activities to rare plants and specifically to these 18 occurrences. Some basic protection activities are identified here.

The O&M plan for these transmission lines should include provisions to update the database of rare plant locations near service-road and transmission-line ROW. These locations should be updated annually based on new information from the USFS, BLM, ORNHP, and IDCDC. In addition, rare plant occurrences on service roads with O&M Risk Index categories of moderate and highest (classes 3 and 4) should be further evaluated to determine whether impacts are occurring, and if they are, a plan should be coordinated with the appropriate land management agencies to protect or enhance those sites. All rare plant occurrences on service roads should be considered constraints to O&M activities, and those occurrences should be evaluated prior to major O&M activities.

Before O&M activities are carried out in areas harboring rare plant species, the known plant sites should be marked on the ground to help ensure that the species can be avoided and protected. However, only those sites that occur directly within the transmission-line ROW or near possible O&M activities need to be marked. If rare species are found before or during maintenance or construction activities, IPC should establish a buffer zone around the occurrence and contact the appropriate federal land management agency.

5.3. Noxious Weeds

Noxious weeds have been a part of rangeland ecosystems for many years. Such weeds began invading North American rangeland habitats as early as the nineteenth century and continue to be introduced today (Sheley and Petroff 1999). Means by which noxious weeds establish and spread are multifaceted, and disturbances that promote such activity are highly interrelated. Weeds are spread in a number of ways including by wind, water, animals, recreation, vehicle travel, and movement of contaminated equipment or products (ODA 2001). Weeds tend to establish in highly disturbed sites such as overgrazed areas, roadsides, trailheads, streambanks, building sites, wildlife bedding grounds, and campgrounds (Sheley and Petroff 1999). Because of the complexity of the spread and establishment of weedy species, it is difficult to make inferences about direct or indirect impacts of individual disturbance types relative to the presence of noxious weeds. Within the study area, widespread disturbance types, including service road construction, livestock, big game, non-project roads, OHVs, road use, and water erosion, cannot easily be related to noxious weed invasions.

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We located 1,118 occurrences of 17 different weed species along service roads in the HCC study area. At least 1 noxious weed was located on 607 of 785 units surveyed (77%). Weedy species tend to invade disturbed ground; however, some are capable of invading healthy communities of native vegetation. The means by which each noxious species spreads and establishes are quite variable. Likewise, the methods for containing or controlling each species vary greatly. Invasion potential, possible impacts, and management techniques for each noxious weed located during surveys are discussed in sections 5.3.1.1 to 5.3.1.14.

5.3.1. Noxious Weed Species

5.3.1.1. Cardaria draba We located Cardaria draba on 146 of 785 units surveyed (19%). Occurrences were highly concentrated in Hells Canyon, with 61 occurrences on Line 903, 57 on Line 904, 10 on Line 905, and 13 on Line 911 (Table 27). Livestock grazing, service road construction, big game, and water erosion comprise the major disturbance types present on survey units containing Cardaria draba.

Invasion Potential and Impacts Cardaria draba grows in open, unshaded areas and generally occupies disturbed ground. It most often invades sub-irrigated pastures, rangeland, ditch banks, roadsides, and waste areas. It is also well adapted to irrigated cropland. Cardaria draba often forms dense monocultures, displacing native plant species, and consequently reduces biodiversity, wildlife habitat, and forage production. The species also competes aggressively with crops for soil moisture and contains glucosinolates, which can be toxic to cattle (Sheley and Stivers 1999).

Management Some forms of mechanical control are effective on Cardaria draba. Hand pulling of above ground parts is ineffective, but small infestations can be removed by digging. Complete plant removal must be achieved and digging generally needs to be repeated for 2 to 4 seasons. Mowing Cardaria draba can reduce biomass and seed production, but mowing alone does not provide long-term control. Mowing combined with herbicide applications can be effective (Sheley and Stivers 1999). Metsulfuron is the most widely recommended herbicide for control of Cardaria draba. Bussan et al. (2001) rate the response of Cardaria draba to metsulfuron as excellent, while rating its response to glyphosate and 2,4-D as fair.

5.3.1.2. Centaurea diffusa We located Centaurea diffusa on 29 of 785 units surveyed (4%). Occurrences were concentrated in the northern portion of the study area, with 10 occurrences on Line 907, 4 occurrences on each of Lines 906, 908, and 912, 2 occurrences on each of Lines 903, 910, and 913, and 1 occurrence on Line 904. Livestock grazing, service road construction, road use, and water erosion comprise the major disturbance types present on survey units containing Centaurea diffusa.

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Invasion Potential and Impacts Centaurea diffusa is most competitive in open habitats with light, well-drained soils. It commonly invades Purshia tridentata/Pseudoroegnaria spicata shrub steppe, short grass steppe, and forest fringes. Centaurea diffusa can reduce biodiversity and land value, increase soil erosion and roadside maintenance costs, and replace wildlife and livestock forage on rangeland and pasture (Roché and Roché 1999).

Management Pulling or digging Centaurea diffusa can be effective if enough of the taproot is removed. Mowing alone is not an effective control method, though it may be used to reduce seed production and plant vigor. Twelve species of insects, now established in the western United States, are available as biological controls for Centaurea diffusa (Roché and Roché 1999). In addition to mechanical and biological control, a number of herbicides have been proven effective on Centaurea diffusa. Picloram and picloram plus 2,4-D both exhibit excellent control on Centaurea diffusa, while clopyralid and clopyralid plus 2,4-D exhibit good to excellent control on the species. The efficacy of either glyphosate or 2,4-D, when used alone, was rated as fair for the control of Centaurea diffusa (Bussan 2001).

5.3.1.3. Chondrilla juncea We located Chondrilla juncea on 212 of 785 units surveyed (27%). Occurrences were concentrated on lines south and east of Brownlee Dam, with 53 occurrences on Line 904, 31 on Line 906, 70 on Line 911, and 58 on Line 912 (Table 27). Livestock grazing, service road construction, fire, road use, big game, and OHV use comprise the major disturbance types present on survey units containing Chondrilla juncea.

Invasion Potential and Impacts Chondrilla juncea thrives in well-drained, sandy-textured, or rocky soils and often dominates land weakened or disturbed by overgrazing or drought. It commonly invades Purshia tridentata/Pseudoroegnaria spicata habitat types and occupies rangeland, pastures, grain fields, roadways, and waste areas. Chondrilla juncea often forms dense monocultures, displacing native plant species, and consequently reduces biodiversity, wildlife habitat, and forage production. The species also competes aggressively with crops for soil moisture, and the wiry stems interfere with harvesting (Sheley et al. 1999b).

Management Hand pulling Chondrilla juncea can be effective if enough of the taproot is removed. Hand pulling generally needs to be repeated for 6 to 10 seasons and is therefore only cost effective for small infestations. Mowing Chondrilla juncea is ineffective, and cultivation spreads root fragments and can increase the area of infestation. In addition to cultural and mechanical control, rust, a mite, and a midge have all been released as biological control agents for Chondrilla juncea in North America (Sheley et al. 1999b). Picloram is the most widely recommended herbicide for control of Chondrilla juncea. Bussan et al. (2001) rate the response of Chondrilla juncea to picloram and picloram plus 2,4-D as excellent, while rating its response to clopyralid plus 2,4-D as good and glyphosate as poor.

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5.3.1.4. Cirsium arvense We located Cirsium arvense on 101 of 785 units surveyed (13%). Occurrences were widespread throughout the study area with concentrations on Lines 907 and 913 between Oxbow and Enterprise (Table 27). Service road construction, livestock grazing, and corridor-clearing comprise the major disturbance types present on survey units containing Cirsium arvense.

Invasion Potential and Impacts Cirsium arvense is most productive in well-aerated soils, but can adapt to a variety of soil types. It is commonly found in open areas along roadsides and in railroad ROW, rangeland, forestland, lawns, gardens, cropland, abandoned fields, streambanks, lakeshores, and other riparian areas. It often forms dense monocultures, which can limit forage and livestock production and reduce land value, crop production, and recreational value (Morishita 1999).

Management Due to the extensive carbohydrate reserves of Cirsium arvense, hand pulling the plant is not generally effective. Repeated cultivation can deplete carbohydrate reserves if shoots are eliminated each time. Mowing Cirsium arvense is most effective when combined with herbicide treatment. In addition to cultural and mechanical control, insects, nematodes, and fungi have all been released as biological control agents for Cirsium arvense in North America. Various herbicides, including 2,4-D, dicamba, clopyralid, metsulfuron, glyphosate, and picloram, are recommended for control of Cirsium arvense; however, effective control from any of these herbicides requires multiple applications (Morishita 1999). Picloram is the most widely recommended herbicide for control of Cirsium arvense. Bussan et al. (2001) rate the response of Cirsium arvense to picloram, picloram plus 2,4-D, clopyralid, and clopryralid plus 2,4-D as excellent, while rating its response to glyphosate as good and its response to dicamba and metsulfuron as fair.

5.3.1.5. Conium maculatum We located Conium maculatum on 10 of 785 units surveyed (1%). Occurrences were concentrated near Brownlee Dam, with 5 occurrences on Line 904, 1 on Line 905, and 4 on Line 911. Livestock grazing, service road construction, and big game comprise the major disturbance types present on survey units containing Conium maculatum.

Invasion Potential and Impacts Conium maculatum is most competitive under wet soil conditions, and it commonly inhabits roadsides, ditch banks and streambanks, creek beds, fence lines, waste places, and cultivated fields. Conium maculatum can invade perennial crops and contaminate seed harvested from grain fields. It also crowds out desirable forage species and causes livestock poisoning and subsequent loss (DiTomaso 1999).

Management Repeated cultivation can prevent establishment of Conium maculatum. Repeated mowing can deplete carbohydrate reserves, prevent seed production, and reduce the competitive ability of the species. One moth species, Agonopterix alstroemeriana (palearctic moth has become established

Page 94 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line in the United States and is a widespread biocontrol agent in Idaho, Oregon, and Washington. Tibuthiuron, chlorosulfuron, metsulfuron, and hexazinone provide effective preemergent control of Conium maculatum. Glyphosate, 2,4-D, and MCPA can also provide effective postemergent control (DiTomaso 1999).

5.3.1.6. Convolvulus arvensis We located Convolvulus arvensis on 75 of 785 units surveyed (10%). Occurrences were concentrated in the northern portion of the study area, with 18 occurrences on Line 903, 22 on Line 904, 10 occurrences on each of Lines 907 and 911 (Table 27). Livestock grazing, service road construction, water erosion, and big game comprise the major disturbance types present on survey units containing Convolvulus arvensis.

Invasion Potential and Impacts Convolvulus arvensis is most competitive in strong sunlight and in areas with moderate to low moisture. It commonly inhabits orchards, vineyards, roadsides, ditch banks, cropland, and streambanks. Convolvulus arvensis can be particularly devastating in agricultural crops because roots, which can penetrate up to 20 ft, compete aggressively for soil moisture. In addition, long vines can climb and choke or topple other species. Convolvulus arvensis has been labeled as 12th most serious weed species for agriculture (Callihan and Miller 1999).

Management Due to extensive root systems, hand pulling Convolvulus arvensis is generally not effective. Tilling 2 weeks after plant emergence can be effective if repeated every 2 weeks of the growing season over a period of 2 to 3 years. Effective biological control agents are not yet available for Convolvulus arvensis (Callihan and Miller 1999). Dicamba, 2,4-D, and picloram are generally recommended for control of Convolvulus arvensis. Bussan et al. (2001) rate the response of Convolvulus arvensis to picloram and picloram plus 2,4-D as good, while rating its response to dicamba, glyphosate, and 2,4-D as fair.

5.3.1.7. Cynoglossum officinale We located Cynoglossum officinale on 160 of 299 units surveyed in Oregon (54%). Occurrences were concentrated in the northern portion of the study area, with 74 occurrences on Line 907, 44 on Line 913, 19 on Line 908, 14 on Line 910, and 8 on Line 903 (Table 27). Service road construction, livestock grazing, corridor clearing, and non-project road use comprise the major disturbance types present on survey units containing Cynoglossum officinale.

Invasion Potential and Impacts Cynoglossum officinale commonly inhabits pastures, roadsides, and other disturbed habitats. The species contains pyrrolizidine alkaloids that can cause liver damage in some mammals. In addition, the barbed seeds of Cynoglossum officinale readily adhere to animal hair, wool, and fur and can cause irritation to range animals and decrease the value of sheep wool. Cynoglossum officinale can also displace native plant species, significantly reducing biodiversity, wildlife habitat, and forage production (Whitson et al. 2000).

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Management No single management method is particularly effective in controlling Cynoglossum officinale. Cultivation of young rosettes in fall or early spring can give effective control, while cutting and mowing are effective in reducing seed set. Prevention, by fostering competing native plants, along with an integrated strategy involving several control methods, is the best strategy for long- term control of Cynoglossum officinale. Effective biocontrol agents are not currently available; however, two potential agents exist: Mogulones cruciger (root-feeding weevil) has been approved and released in Canada, and Longitarsus quadriguttatus (root-feeding flea-beetle) has shown promise, but may affect other members of the North American Boraginaceae (Washington State Noxious Weed Control Board 2001). Dicamba, 2,4-D, metsulfuron, and picloram are generally recommended for control of Cynoglossum officinale. Bussan et al. (2001) rate the response of Cynoglossum officinale to metsulfuron as excellent, while rating its response to picloram and dicamba as good and 2,4-D as fair.

5.3.1.8. Dipsacus sylvestris We located Dipsacus sylvestris on 39 of 299 units surveyed in Oregon (13%). Occurrences were concentrated in the northern portion of the study area, with 18 occurrences on Line 908, 15 on Line 903, 4 on Line 907, and 2 on Line 913. Service road construction, livestock, water erosion, big game, and non-project road use comprise the major disturbance types present on survey units containing Dipsacus sylvestris.

Invasion Potential and Impacts Dipsacus sylvestris prefers moist sites with rich soils and increases with disturbance. It is common in meadows and waste areas and is often found along roadsides, irrigation ditches, and canals (Whitson et al. 2000). Dipsacus sylvestris is a common agricultural pest in both corn and sorghum crops (Bussan et al. 2001).

Management Literature on the control of Dipsacus sylvestris in North America is lacking; however, a number of herbicides provide effective control of the species. Dicamba, 2,4-D, metsulfuron, and chlorosulfuron are commonly recommended for control of Dipsacus sylvestris (William et al. 1999). Bussan et al. (2001) do not rate herbicide responses for Dipsacus sylvestris.

5.3.1.9. Euphorbia esula We located Euphorbia esula on 7 of 785 units surveyed (< 1%). Occurrences were east of Brownlee Dam, with 33 occurrences on Line 904 and 4 occurrences on Line 911. Livestock grazing, big game, service road construction, water erosion, and OHV use comprise the major disturbance types present on survey units containing Euphorbia esula.

Invasion Potential and Impacts Euphorbia esula is most productive in bottomlands. It thrives in a variety of soil types and is particularly competitive in disturbed soils. Euphorbia esula commonly inhabits pastures, rangelands, roadsides, waste areas, and abandoned cropland. It is a highly competitive plant that often forms dense monocultures, consequently displacing native vegetation. Euphorbia esula

Page 96 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line reduces plant diversity, wildlife forage and habitat, and rangeland productivity. Where heavy infestations occur, land value is greatly reduced because of the difficulty and expense of controlling Euphorbia esula.

Management Hand pulling Euphorbia esula is generally ineffective due to the depth of the root system and numerous root buds. Intensive cultivation throughout the growing season or cultivation of regrowth in the fall can effectively reduce Euphorbia esula. Mowing and burning are ineffective, though burning prior to herbicide applications can increase weed visibility and spray coverage. Thirteen species of insect biological control agents are available for Euphorbia esula control in the United States. In addition, sheep and goats will graze the species. Dicamba, 2,4-D, imazapic, picloram, and glyphosate are commonly recommended for control of Euphorbia esula. Bussan et al. (2001) rate the response of Euphorbia esula to imazapic, picloram, and glyphosate as good, while rating its response to dicamba and 2,4-D as fair.

5.3.1.10. Hypericum perforatum We located Hypericum perforatum on 69 of 299 units surveyed in Oregon (23%). Occurrences were concentrated in the northern portion of the study area, with 33 occurrences on Line 907, 18 on Line 908, 9 on Line 903, and 5 on Line 910 (Table 27). Service road construction, livestock grazing, and water erosion comprise the major disturbance types present on survey units containing Hypericum perforatum.

Invasion Potential and Impacts Hypericum perforatum is a highly competitive plant that thrives in well-drained, gravelly, or sandy soils in open, sunny sites. The species increases with disturbance and commonly inhabits pastures, rangeland, forest clearings, transportation ROW, and neglected lands. Hypericum perforatum displaces native vegetation and valued forage and reduces species diversity as well as livestock and wildlife carrying capacities (Piper 1999).

Management Hand-pulling or digging small infestations of young Hypericum perforatum plants can be effective if the entire plant is removed; however, hand-pulling is not practical for large occurrences of older, deeply rooted plants. Repeated tillage can be effective on Hypericum perforatum occurring in areas that are intensively put into crops. Cutting and mowing are largely ineffective, though they can reduce spread of the plant if they are implemented before seed production occurs. Several insects have been approved for use as biological controls of Hypericum perforatum in the United States (Piper 1999). Metsulfuron, 2,4-D, and picloram are commonly recommended for control of Hypericum perforatum. Bussan et al. (2001) do not rate herbicide responses for Hypericum perforatum.

5.3.1.11. Onopordum acanthium We located Onopordum acanthium on 157 of 785 units surveyed (20%). Occurrences were widespread, but concentrated in the northern portion of the study area, with 40 occurrences on Line 903, 33 on Line 904, 43 on Line 915, 13 on Line 907, and 16 on Line 911 (Table 27).

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Livestock grazing, service road construction, big game, and water erosion comprise the major disturbance types present on survey units containing Onopordum acanthium.

Invasion Potential and Impacts Onopordum acanthium is most productive in areas with high soil moisture. It often inhabits swales, gullies, draws, meadows, and pastures, as well as abandoned land and roadside ditches. Onopordum acanthium competes with and decreases desirable forage in pastures. In addition, the spiny nature of the species often deters livestock (Beck 1999).

Management Because Onopordum acanthium is a biennial thistle, tilling, hoeing, digging, and even hand-pulling can provide effective control when population sizes are manageable. Mowing is not very effective, but can reduce seed production. Biological controls are not yet available specifically for Onopordum acanthium (Beck 1999). Picloram, clopyralid, metsulfuron, 2,4-D, and dicamba are commonly recommended for control of Onopordum acanthium. Bussan et al. (2001) rate the response of Onopordum acanthium to picloram, picloram plus 2,4-D, metsulfuron, and clopyralid as excellent, while rating its response to clopryalid plus 2,4-D as good and its response to 2,4-D and dicamba as fair.

5.3.1.12. Rumex crispus We located Rumex crispus on 41 of 299 units surveyed in Oregon (14%). Occurrences were concentrated in the northern portion of the study area, with 19 occurrences on Line 903, 7 on Line 907, 11 on Line 908, and 4 on Line 913. Service road construction, livestock grazing, and water erosion comprise the major disturbance types present on survey units containing Rumex crispus.

Invasion Potential and Impacts Rumex crispus is most productive in areas with high soil moisture. It often inhabits crops, wet meadows, pastures, ditch banks, and waste areas. Rumex crispus competes with and decreases desirable forage in pastures and on rangeland (Whitson et al. 1999). Rumex crispus is a common agricultural pest in alfalfa, corn, sorghum, potato, and sugar beet crops (Bussan et al. 2001).

Management Literature on the control of Rumex crispus in North America is lacking; however, a number of herbicides provide effective control of the species. Dicamba, 2,4-D, picloram, metsulfuron, chlorosulfuron, and glyphosate are commonly recommended for control of Rumex crispus (William et al. 1999). Bussan et al. (2001) do not rate herbicide responses for Rumex crispus.

5.3.1.13. Taeniatherum caput-medusae We located Taeniatherum caput-medusae on 64 of 299 units surveyed in Oregon (21%). Occurrences were concentrated along Line 903 (Table 27). Livestock grazing, service road construction, big game, non-project roads, road use, and OHV use comprise the major disturbance types present on survey units containing Taeniatherum caput-medusae.

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Invasion Potential and Impacts Taeniatherum caput-medusae often invades native vegetation in areas weakened by overgrazing, intense fires, or cultivation. It is an aggressive annual grass that can out-compete previously established weeds including Bromus tectorum. It can also crowd out perennial grass seedlings. Dense litter from Taeniatherum caput-medusae can burn readily, encouraging frequent fire disturbance. Taeniatherum caput-medusae greatly reduces rangeland production and value as high amounts of silica in the species make it coarse and unpalatable to livestock (Miller et al. 1999).

Management Because Taeniatherum caput-medusae is an annual grass, spring plowing or disking after germination can be an effective control method. Fusarium culmorum (crown rot), a pathogen commonly found on wheat, has been shown to cause severe disease on Taeniatherum caput-medusae. This pathogen is promising as it has a much less severe effect on native grasses often associated with Taeniatherum caput-medusae. Glyphosate, atrazine, bromacil, siduron, and dalapon are recommended herbicides for the control of Taeniatherum caput-medusae. Glyphosate is best when applied before the seed head is produced. Atrazine, bromacil, and siduron are all pre-emergent, soil-active herbicides. Dalapon works best when applied to foliage during the vegetative stage (Miller et al. 1999).

5.3.1.14. Other weed species Aegilops cylindrica We located Aegilops cylindrica on 2 units along Line 904 in Idaho. Disturbance intensity from service road construction was moderate on one unit and high on the other, while livestock disturbance was moderate on both, big game disturbance was slight on both, and non-project road use was moderate on one. No other disturbance types were recorded on the units associated with Aegilops cylindrica.

Aegilops cylindrica is most commonly found in wheat fields, but also invades roadsides, waste areas, alfalfa fields, and pastures. Because Aegilops cylindrica reproduces primarily by seed, spring tillage can provide excellent control (Callihan and Miller 1999). Biological control agents are not yet available. Sulfometuron and glyphosate provide good control of Aegilops cylindrica (Bussan et al. 2000), but no herbicides are available that provide selective control of the species (Callihan and Miller 1999).

Centaurea maculosa We located 1 occurrence of Centaurea maculosa on Line 905 in Oregon. Livestock disturbance was moderate, while agriculture, big game, and water erosion were each slight on the unit. No other disturbance types were recorded on the units associated with Centaurea maculosa.

Centaurea maculosa readily establishes on disturbed soils. It contaminates such crops as alfalfa and clover, and it is a problem weed on rangeland and pastures (Whitson et al. 2000). Persistent hand-pulling and repeated cultivation up to 18 cm (7 inches) can both provide good control of Centaurea maculosa. Two seedhead-feeding flies and four root-mining insects have been approved in the United States for controlling Centaurea maculosa. In addition, a soil fungus and

Hells Canyon Complex Page 99 Effects of Road and Transmission Line Idaho Power Company a bacterial pathogen are also available for biological control of the species (Sheley et al. 1999c). Bussan (2001) rates the response of Centaurea maculosa to picloram and clopyralid as excellent and its response to dicamba and 2,4-D as good.

Centaurea repens We located Centaurea repens on 3 units in Oregon, with 2 occurrences on Line 913 and 1 on Line 907. Disturbance intensity from service road construction was slight on all units, while disturbance from corridor clearing was high. Livestock grazing and non-project road disturbances were each slight on two units. Water erosion and big game disturbance were each slight on one unit. No other disturbance types were recorded on units associated with Centaurea repens.

Centaurea repens invades open, disturbed sites, and commonly inhabits cultivated fields, orchards, pastures, streambanks, and roadsides (Whitson et al., 1999). Among the biological control agents available for Centaurea repens, two seedhead gall flies and one seedhead moth have been effective (Callihan and Miller 1999). Metsulfuron, picloram, clopryalid, and 2,4-D are commonly recommended for the control of Centaurea repens. Bussan (2001) rates the response of Centaurea repens to picloram and picloram plus 2, 4-D as excellent, its response to clopyralid and clopyralid plus 2, 4-D as good, and its response to dicamba and metsulfuron as fair.

Tribulus terrestris (puncturevine) We located 2 occurrences of Tribulus terrestris in Oregon, with 1 occurrence on Line 903 and 1 on Line 905. Disturbance intensity from service road construction was moderate on one unit and high on the other, while disturbance from road use was high on one unit, and OHV use was slight on one unit. No other disturbance types were recorded on units associated with Tribulus terrestris.

Tribulus terrestris prefers sandy, dry, or gravelly sites and is commonly found in pastures, roadsides, waste places, and cultivated fields. Repeated cultivation after germination, but before seed set, can be effective. Two weevils have been approved as biological controls for Tribulus terrestris in the United States. Also, 2,4-D and chlorosulfuron are commonly recommended for control of the species, and picloram can provide adequate, though not complete, control of the species when applied as a pre-emergent spray (Washington State Noxious Weed Control Board 2001).

5.3.2. Distribution of Major Noxious Weed Occurrences

Five of the 17 weed species occurred on 10% or more of the survey units. Chondrilla juncea was most commonly recorded, occurring on 27% of units surveyed, followed by Cynoglossum officinale and Onopordum acanthium, both present on 20%; Cardaria draba, present on 19%; and Cirsium arvense, present on 13%. Chondrilla juncea occurrences were concentrated on lines south and east of Brownlee Dam (i.e., Lines 904, 906, 911, and 912), while the other 4 most commonly recorded species were concentrated in the northern portion of the study area. Onopordum acanthium was concentrated on Lines 903, 904, 905, 907 and 911, Cirsium arvense was concentrated on Lines 907 and 913, and Cardaria draba was concentrated on Lines 903, 904, 905, and 911. Cynoglossum officinale is abundant in both Idaho and Oregon; however, it

Page 100 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line was only recorded on survey units occurring within Oregon because it is not considered noxious in Idaho. As a result, the concentration of Cynoglossum officinale occurrences north and west of Brownlee Dam is misleading. Chondrilla juncea, Onopordum acanthium, Cardaria draba, and Cirsium arvense are all noxious in both Idaho and Oregon.

5.3.3. Major Disturbance Types Associated With Noxious Weed Occurrences

Service road condition and livestock grazing were the major disturbance types present on survey units where noxious weed species were recorded. Big game use and water erosion were disturbance factors in many areas. Corridor clearing, fire, OHVs, and non-project road use were more site-specific disturbance factors. Agriculture, industry, logging, and residential use were not major disturbance factors associated with noxious weeds. Because we rated disturbance types and intensities on qualitative scales, the responses of noxious weeds to disturbance factors were not directly evaluated.

Of the four most common disturbance types, service road disturbance is the only one directly related to IPC activities. Livestock and big game disturbances are directly attributable to livestock or big game activities, and water erosion disturbance is directly attributable to flooding and overland flow of water. On the other hand, service road disturbance is directly attributable to construction of the service road and includes disturbance related to road cuts or tower site pads created during construction of the ROW. Service road disturbance includes only the area on or associated with the immediate roadway (i.e., it does not include the 50-m buffer zone on each side of the roadway) and does not include current disturbance caused by other roads intersecting the road being surveyed, disturbance caused by OHVs, or damage to the road caused by water erosion (disturbance type definitions are further outlined in Appendix 9).

Although service road disturbance was recorded on 99% of units surveyed, it must be noted that the service roads were the reason for the study and were expected to have a high frequency. It is also important to keep in mind the rating scale for such disturbance (Appendix 9). For service road disturbance, an intensity rating of slight merely indicates that the service road was present, but barely noticeable; a rating of moderate indicates that road cuts are present, but limited in size and area and generally stabilized by vegetation; a rating of high indicates that road cuts are present and occur along most of the length of the survey unit with minimal stabilization; and a rating of extreme indicates that steep, bare road cuts occur along most of the length of the unit, with little to no stabilization. The majority of service road disturbance was minimal, with 17% of units rated as slight and 69% rated as moderate, while only 12% were rated as high and less than 1% as extreme.

5.3.4. Management Implications for Noxious Weeds

We recommend working cooperatively with federal land management agencies and other private landowners to control establishment and spread of noxious weeds. Specifically, we recommend participating with local Cooperative Weed Management Areas for the areas that are traversed by the transmission-line ROW. These groups build cooperative relationships among agencies,

Hells Canyon Complex Page 101 Effects of Road and Transmission Line Idaho Power Company landowners, land managers, and other interested individuals and organizations—relationships that are needed for effective management of noxious weeds.

Specific goals of cooperative efforts should include the following: • Prevent the introduction, reproduction, and spread of designated noxious weeds and invasive exotic plants along transmission-line corridors, • Reduce the extent and density of established noxious weeds to a point that natural resource damage is within some acceptable limits, • Restore/revegetate infested areas to reduce re-invasive potential, • Implement the most effective, economical, and appropriate control methods for each specifically targeted weed or infestation, • Implement an integrated management system that uses all appropriate, available methods or combination of methods for specific sites or weed species. Management priorities would 1) prevent the initial establishment of listed noxious weeds, 2) eradicate new invaders if technically possible or economically feasible, 3) treat new satellite infestations of listed weeds, and 4) treat centers of established noxious weeds.

Specific management practices to control noxious weed sites and to restore and revegetate areas disturbed by O&M activities should be identified in an O&M plan for the transmission lines. These practices should include the following concepts, which would minimize negative impacts from O&M activities on the spread of noxious weeds throughout the study area.

Because maintenance vehicles and equipment can transport weed seeds from one area to another through dirt and debris that collect on the equipment, care should be taken to assure that the equipment is weed free. Before beginning an O&M project on public lands, employees should clean all equipment that will operate off-road or disturb ground. The cleaning process should involve washing tracks and other parts of the equipment that could trap soil and debris. Equipment should be cleaned with high-pressure water or compressed air and in a relatively flat area away from flowing water to prevent seed from being transported downstream. Preferably, the wash-down should occur at an operation center or commercial car wash. Construction vehicles traveling only on bladed areas and roads would not be required to be washed down.

To help limit the reestablishment and spread of noxious weeds, disturbed areas should be reseeded as soon as possible, but during the optimal planting period following disturbance activities. Weather, soil conditions, and scheduling would affect reseeding dates. In some cases, revegetation operations may not be necessary, given limited amount of soil compaction and vegetation destruction. For each project, the degree and methods used in revegetation efforts should be coordinated with the federal land management agencies. It is anticipated that IPC would provide all seed used in the projects. The seed mix should meet all requirements of the Federal Seed Act and of applicable Oregon and Idaho laws about seeds and noxious weeds. Only seed certified as noxious weed free should be used. If requested, IPC should provide the federal land managers with evidence of seed certification. Seed should be appropriate to the geographic and elevation characteristics of the area to be seeded.

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Along the transmission lines, the best time to seed is in the fall (September to November). If seeding cannot be done then, spring seeding should take place as conditions dictate. Following reseeding activities and in consultation with federal land managers, IPC should monitor reseeding projects to insure that an agreed-upon level of vegetation cover exists after two growing seasons. If success criteria are not met, IPC should compensate by doing a one-time reseeding during a period acceptable to the federal agencies.

6. ACKNOWLEDGMENTS

We thank Kelly Wilde for coordinating the field surveys and supervising the field crews. We had excellent field crews, including Heather Swartz, Holly Nielsen, Lisa Hahn, Rhett Johnson, and Casey Pevey. Chris Huck, Sonny Cabbage, and Sam Adams provided GIS and GPS support to the project. Natalie Sunderman-Turley coordinated the snag study. Lynnette Blas and Patty Auch provided administrative support. Vicki Aguirre and the group at IPC Corporate Publishing helped get us out of some word processing jams. Steve Popovich and Lynda Smithman verified voucher specimens. Chavez Writing & Editing provided critical editing to the report. Thank you to everyone who helped produce this report.

7. LITERATURE CITED

Alt, D. D. and D. W. Hyndman. 1989. Roadside geology of Idaho. Mountain Press Publishing Co., Missoula, MT.

Anderson, S. H., K. Mann, and H. H. Shugart. 1977. The effect of transmission-line corridors on bird populations. Am. Midl. Natur. 97(1):216-221.

Barneby, R. C. 1989. Fabales. Pages 39-176 in: A. C. Cronquist, A. H. Holmgren, N. H. Holmgren, and J. L. Reveal (eds.). Intermountain flora: vascular plants of the Intermountain West, U.S.A. Vol. 3, Part B. New York Botanical Garden, N.Y.

Bate, L. J., E. O. Garton, and M. J. Wisdom. 1999. Estimating snag and large tree densities and distribution on a landscape for wildlife management. PNW-GTR-425. USDA For. Serv. Pacific Northwest Res. Sta., Portland, OR. 76 p.

Beck, K. G. 1999. Biennial thistles. Pages 145−161 in: R. L. Sheley and J. K. Petroff (eds.). Biology and management of noxious rangeland weeds. Oregon State Univ. Press, Corvallis.

Beck, H. H. and N. K. Cole. 2000. Vegetation of the Upper and Lower Malad Study Area. New license application: Malad Hydroelectric Project. Technical Report E.3.3-A. Idaho Power, Boise, ID. 36 p.

Hells Canyon Complex Page 103 Effects of Road and Transmission Line Idaho Power Company

Beley, J. R., T. M. Butt, and C. D. Johnson. 1982. Arthropods, plants and transmission lines in : community dynamics during secondary succession in a pinyon-juniper chaparral habitat. Southwest Nat. 27:325−333.

Bramble, W. C. and W. R. Byrnes. 1983. Thirty years of research on development of plant cover on an electric transmission rights-of-way. J. Arboricult. 9:67−74.

Brisson, J., A. Meileur, M. Fortin, and A. Bourchard. 1997. Edge effects on vegetation in rights-of-way. Pages 25-34 in: J. R. Williams, J. W. Goodrich-Mahoney, J. R. Wisniewski, and J. Wisnieski (eds.). Environmental concerns in rights-of-way management: the sixth international symposium. Elsevier Science LTD, United Kingdom.

Brody, A. J. and M. R. Pelton. 1989. Effects of roads on black bear movements in western North Carolina. Wildl. Soc. Bull. 17(1):5−10.

Brothers, T. S. and A. Spingarn. 1992. Forest fragmentation and alien plant invasion of central Indiana old-growth forests. Conserv. Biol. 6(1):91−100.

Brown, D. 1994. The development of woody vegetation in the first 6 years following clearcutting of a hardwood forest for a utility rights-of-way. For. Ecol. and Manage. 65:171−181.

Brown, P. M., M. R. Kaufmann, and W. D. Shepperd. 1999. Long-term, landscape patterns of past fire events in montane ponderosa pine forest of central Colorado. Landscape Ecol. 14:513−532.

Bull, E. L., C. G. Parks, and T. R. Torgersen. 1997. Trees and logs important to wildlife in the interior Columbia River basin. USDA For. PNW-GTR-391. USDA For. Serv. Pacific Northwest Res. Sta., Portland, OR. 55 p.

Bull, E. L. and R. S. Holthausen. 1993. Habitat use and management of pileated woodpeckers in northeastern Oregon. J. Wildl. Manage. 57(2):335−345.

Bussan, A. J., S. D. Dewey, T. D. Whitson, and M. A. Trainor (eds.). 2001. Weed management handbook: 2001−2002. Coop. Ext. Serv., Montana. 294 p.

Callihan, R. H. and T. W. Miller. 1999. Idaho’s noxious weeds. Univ. Idaho, Moscow. 74 p.

Champlin, J. B. F. 1973. Ecological studies along transmission lines in southwestern United States. J. Environ. Sci. 16:11−18.

Chen, J., J. F. Franklin and S. J. Lowe. 1996. Comparison of abiotic and structurally defined patch patterns in a hypothetical forest landscape. Conserv. Biol. 10:854−862.

Chen, J., J. F. Franklin and T. A. Spies. 1993. Contrasting microclimates among clearcut, edge, and interior old growth Douglas-fir forest. Agricult. and For. Meteorol. 63:219−237.

Page 104 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line

Chen, J., S. C. Saunders, T. R. Crow, R. J. Naiman, K. D. Brosofske, G. D. Mroz, B. L. Brookshire, and J. F. Franklin. 1999. Microclimate in forest ecosystem and landscape ecology. BioScience 49(4):288−297.

Clausnitzer, R. R. 1993. The grand fir series of northeastern Oregon and southeastern Washington: successional stages and management guide. USDA For. Serv., Pac. Northw. Region, Wallowa-Whitman Nat. For. R6-ECO-TP-050-93. 193 p.

Clary, W. P. and W. C. Leininger. 2000. Stubble height as a tool for management of riparian areas. J. Range Manag. 53:562−573.

Cole, D. N. 1988. Disturbance and recovery of trampled montane grassland and forests in Montana. USDA For. Serv. Intermountain Res. Sta. Res. Paper INT-389. 37 p.

Covington, W. W. and S. S. Sackett. 1984. The effects of a prescribed burn in southwestern ponderosa pine on organic matter and nutrients in woody debris and forest floor. For. Sci. 30(1):183−192.

Cronquist, A. C. 1994. . Pages - in: A. C. Cronquist, A. H. Holmgren, N. H. Holmgren, J. L.Reveal, and P. K. Holmgren (eds.). Intermountain flora: vascular plants of the Intermountain West, U.S.A. Vol. 5. New York Botanical Garden, N.Y.

Cronquist, A. C., A. H. Holmgren, N. H. Holmgren, J. L. Reveal, and P. K. Holmgren. 1977. Intermountain flora: vascular plants of the Intermountain West, U.S.A. Vol. 6. The . Columbia Univ. Press, N.Y. 584 p.

Cronquist, A. C., A. H. Holmgren, N. H. Holmgren, J. L. Reveal, and P. K. Holmgren. 1984. Intermountain flora: vascular plants of the Intermountain West, U.S.A. Vol. 4. Subclass Asteridae (except ). New York Botanical Garden, N.Y. 573 p.

Cronquist, A. C., N. H. Holmgren, and P. K. Holmgren. 1997. Intermountain flora: vascular plants of the Intermountain West, U.S.A. Vol. 3, Part A. Subclass Rosidae (except Fabales). New York Botanical Garden, N.Y.

Crowe, E. A. and R. R. Clausnitzer. 1995. Mid-Montane wetlands classification of the Malheur, Umatilla, and Wallowa-Whitman National Forests. USDA For. Serv., Pac. Northw. Reg. 187 p.

DeBolt, A. 1989. An illustrated guide to the sensitive plants of Burley District, Idaho BLM. Tech. Bull. 89-3. 40 p.

DeBolt, A. and R. Rosentreter. 1988. An illustrated guide to the sensitive plants of Boise District, Idaho BLM. Tech. Bull 88-4. 81 p.

DiTomaso, J. M. 1999. Poison-hemlock. Pages 290-297 in: R. L. Sheley and J. K. Petroff (eds.). Biology and management of noxious rangeland weeds. Oregon State Univ. Press, Corvallis.

Hells Canyon Complex Page 105 Effects of Road and Transmission Line Idaho Power Company

Douglas, A. J. and R. L. Johnson. 1994. Drainage investment and wetlands loss: an analysis of the natural resources inventory data. J. Environ. Manage. 40:341−355.

Dumas, B. C. and L. B. Carpenter. 2001. Effects of roads and transmission-line rights-of-way on wildlife resources including species of special concern. In: Technical appendices for new license application: Hells Canyon Hydroelectric Project. Technical Report E.3.2-37. Idaho Power, Boise, ID.

Elkie, P., R. Rempel, and A. Carr. 1999. Patch analyst user’s manual. Ont. Min. Natur. Resour. Northwest Sci. and Technol. TM-002. Thunder Bay, Ont. 16 p. + append.

Ellis, D. H., J. G. Goodwin, Jr., and J. R. Hunt. 1978. Wildlife and electric power transmission. Pages 81-168 In: J. L. Fletcher and R. G. Busnel (eds.). Effects of noise on wildlife. Academic Press, Inc., New York.

Environmental System Research Institute (ESRI). 1992. Understanding GIS: the ARC/INFO method. Environmental Systems Research Institute, Redlands, CA.

Franklin, J. F. and C. T. Dyrness. 1988. Natural vegetation of Oregon and Washington. Oregon State Univ. Press, Corvallis.

Freedman, J. D. and J. R. Habeck. 1985. Fire, logging, and white-tailed deer interrelationships in the Swan Valley, Western Montana. In: USDA Forest Service, 1986, Fire’s effects on wildlife habitat—symposium proceedings (Missoula, MT, March 21, 1984). USDA For. Serv. Intermountain Res. Sta. Gen. Tech. Rept. INT186. Ogden, UT.

Garcia and Associates (GANDA). 1996. Impacts of hydroelectric operations on botanical and wildlife resources: a literature review. Draft report. Garcia and Associates, Tiburon, CA. 59 p.

Greenberg, C. H., S. H. Crownover, and D. R. Gordon. 1997. Roadside soils: a corridor for invasion of xeric scrub by nonindigenous plants. Natur. Areas J. 17(2):99−109.

Harrod, R. J., W. L. Gaines, W. E. Hartl, and A. Camp. 1998. Estimating historical snag density in dry forests east of the Cascade Range. USDA, Forest Service, Pacific Northwest Research Station, Portland, OR. 16 P.

Hassan, M. A. and N. E. West. 1986. Dynamics of soil seed pools in burned and unburned sagebrush semi-deserts. Ecol. 67(1):269−272.

Hawkins, C. P. 1994. What are riparian ecosystems and why are we worried about them? Pages 1−9 In: G. A. Rasmussen and J. P. Dobrowki (eds.). Riparian resources: a symposium on the disturbances, management, economics, and conflicts associated with riparian ecosystems. Coll. Nat. Res., Utah State Univ., Logan.

Hemker, T. 1997. Idaho sage grouse management plan. Idaho Dept. Fish and Game, Boise.

Page 106 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line

Hessing, M. B. and C. D. Johnson. 1982. Disturbance and revegetation of Sonoran Desert vegetation in an Arizona powerline corridor. J. Range Manage. 35:254−258.

Heyerdahl, E. K., L. B. Brubaker, and J. K. Agee. 2001. Spatial controls of historical fire regimes: a multiscale example from the interior west, USA. Ecol. 82(3):660−678.

Hickman, J. C. (ed.). 1993. The Jepson manual: higher plants of California. Univ. California Press, Berkeley. 1400 p.

Hitchcock, C. L. and A. Cronquist. 1973. Flora of the Pacific Northwest. Univ. Washington Press, Seattle. 730 p.

Hitchcock, C. L., Cronquist, A., Ownbey, M., and J. W. Thompson. 1977−1997. Vascular plants of the Pacific Northwest. Univ. Washington Press, Seattle. 5 vols.

Holmstead, G. L. 2001. Vegetation of the Snake River corridor in Hells Canyon—Weiser, Idaho, to the . In: Technical appendices for new license application: Hells Canyon Hydroelectric Project. Technical Report E.3.3-1. Idaho Power, Boise, ID.

Homer, C. G. 1998. Idaho/Western Wyoming landcover classification: report and metadata. Dept. Geography and Earth Res., Utah State Univ., Logan.

Hull, A. C. and M. K. Hull. 1974. Presettlement vegetation of Cache Valley, Utah and Idaho. J. Range Manage. 27(1):27−29.

Huschle, G. 1975. Analysis of the vegetation along the middle and lower Snake River. Univ. Idaho, Moscow. 269 p.

Idaho Conservation Data Center (IDCDC). 2001a. Element occurrence record database and species rankings. Idaho. Dept. Fish and Game, IDCDC, Boise, ID.

Idaho Conservation Data Center (IDCDC). 2001b. Species of conservation concern: special status species. http://www2.state.id.us/fishgame/info/cdc/cdc.htm and http://www2.state.id.us/fishgame/info/cdc/rare.htm.

Idaho State Department of Agriculture (ISDA). 1999. Idaho’s strategic plan for managing noxious weeds. ISDA, Boise. 22 p.

Idaho State Department of Agriculture (ISDA). 2000. Idaho pesticide applicator training manual. ISDA, Boise. 148 p.

Johnson, C. G. and S. A. Simon. 1987. Plant associations of the Wallowa-Snake Province, Wallowa-Whitman National Forest. USDA For. Serv., Pacific Northw. Reg. R6-ECOL- TP-255A-86. Enterprise, Ore. 399 p.

Johnson, F. D. and D. J. Mattson. 1978. A survey of sensitive plants of the Snake River corridor, Hells Canyon National Recreation Area, USFS. College of Forest, Wildlife and Range Science, Univ. Idaho, Moscow. 114 p.

Hells Canyon Complex Page 107 Effects of Road and Transmission Line Idaho Power Company

Kapos, V. 1989. Effects of isolation on the water status of forest patches in the Brazilian Amazon. J. Tropical Ecol. 5:173−185.

Kay, C. E. 1995. Browsing by native ungulates: effects on shrub and seed production in the Greater Yellowstone Ecosystem. Pages 310-320 In: B. A. Roundy, E. D. McArthur, J. S. Haley, and D. K. Mann (comps.). Proceedings: wildland shrub and arid land restoration symposium (Las Vegas, Nev, 1993). USDA For. Serv., Intermountain Res. Sta., Ogden, UT.

Kiilsgaard, C. 1999. Land cover type descriptions: Oregon GAP analysis—1998 land cover for Oregon. Oregon Natural Heritage Program, Portland, OR.

Knick, S. T. and J. T. Rotenberry. 1995. Landscape characteristics of fragmented shrubsteppe habitats and breeding passerine birds. Conserv. Biol. 9(5):1059−1071.

Knick, S. T. and J. T. Rotenberry. 1997. Landscape characteristics of disturbed shrubsteppe habitats in southwestern Idaho (U.S.A.). Landscape Ecol. 12:287−297.

Krichbaum, R. S. 1995. Rare plant survey: Idaho Power Company Brownlee-Oxbow Transmission Line. Technical Report 95-03. Eagle Cap Consulting, Enterprise, Ore. 34 p.

Kroodsma, R. L. 1987. Edge effect on breeding birds along power-line corridors in east Tennessee. Am. Midl. Natur. 118(2):275−283.

Lidicker, W. Z., Jr. 1999. Responses of mammals to habitat edges: an overview. Landscape Ecol. 14:333−343.

Little, S. N. and J. L. Ohmann. 1988. Estimating nitrogen loss from forest floor during prescribed fires in Douglas-fir/western hemlock clearcuts. For. Sci. 34(1):152−164.

Loney, B. and R. J. Hobbs. 1991. Management of vegetation corridors: maintenance, rehabilitation and establishment. Pages 299−311 in D.A. Saunders and R. J. Hobbs, eds. Nature conservation 2: The role of corridors.

Luken, J. O., A. C. Hinton, and D. G. Baker. 1991. Forest edges associated with power-line corridors and implications for corridor siting. Land. Urban Plann. 20:315−324.

Luken, J. O., A. C. Hinton, and D. G. Baker. 1992. Response of woody plant communities in power-line corridors to frequent anthropogenic disturbance. Ecol. Appl. 2(4):356−362.

MacLellan, P. and J. M. Stewart. 1986. Latitudinal gradients in vegetation along a disturbed transmission line rights-of-way in Manitoba. Canadian J. of Botany 64:1311−1320.

Mancuso, M. 1995a. A vegetation map of the Rocking M Ranch, Upper Dennett Creek/Raft Creek Wildlife Conservation Easement Area, Washington County, Idaho. Idaho Dept. Fish Game, Boise. 66 p.

Page 108 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line

Mancuso, M. 1995b. Draft habitat conservation assessment for Allium aaseae Ownbey (Aase's onion). Conservation Data Center, Idaho Department of Fish and Game, Boise. 19 p.

Mancuso, M. and R. Moseley. 1995. A vegetation map for Brownlee Wildlife Management Area, Washington County, Idaho. Idaho Dept. Fish Game, Boise. 112 p.

McCann, J. M. 1999. Before 1942: the making of the Pre-Columbian landscape. Ecol. Restoration. 17 (1&2):15−30.

McCollough, S. A. and T. W. Ring. 1990. Electrical transmission lines in Montana: mitigation of impacts to soil and biological resources. Pages 336−345 in: Fifth Billings symposium on disturbed land rehabilitation, Vol. II. Reclamation Res. Unit Publ. 9003. Montana State Univ., Bozeman.

McGarigal, K. and B. J. Marks. 1995. FRAGSTATS: spatial pattern analysis program for quantifying landscape structure. USDA For. Serv. Gen. Tech. Rep. PNW-GTR-351. Pacific Northwest Res. Sta., Portland, OR.

McIvor, J. G. 1997. Pasture management in semi-arid tropical woodlands: effects on species diversity. Austr. J. Ecol. 23:349−364.

Melgoza, G., R. S. Nowak, and R. J. Tauch. 1990. Soil water exploitation after fire: competition between Bromus tectorum (cheatgrass) and two native species.

Miller, H. C., D. Clausnitzer, and M. M Borman. 1999. Medusahead. Pages 271−281 in: R. L. Sheley and J. K. Petroff (eds.). Biology and management of noxious rangeland weeds. Oregon State Univ. Press, Corvallis.

Miller, T. L. 1993. Oregon pesticide applicator manual: a guide to the safe use and handling of pesticides. EM8532. Oregon State Univ. Ext. Office, Corvallis. 280 p.

Morishita, D. 1999. Canada thistle. Pages 162-174 in: R. L. Sheley and J. K. Petroff (eds.). Biology and management of noxious rangeland weeds. Oregon State Univ. Press, Corvallis.

Morrow, S. D. 1997. Effective integrated vegetation management. Pages 127-132 in: J. R. Williams, J. W. Goodrich-Mahoney, J. R. Wisniewski, and J. Wisnieski (eds.). Environmental concerns in rights-of-way management: the sixth international symposium. Elsevier Science LTD, United Kingdom.

Moseley, R. K. 1989. Field investigations of Leptodactylon pungens ssp. hazeliae (Hazel's prickly phlox) and Mirabilis macfarlanei (Macfarlane's four-o-clock), Region 4 sensitive species, on the Payette National Forest, with notes on Astragalus vallaris (Snake Canyon milkvetch) and Rubus bartonianus (bartonberry). Idaho Dept. Fish and Game, Conservation Data Center, Boise. 16 p.

Noss, R. F. 1983. A regional landscape approach to maintain diversity. BioSci. 33: 700−706.

Hells Canyon Complex Page 109 Effects of Road and Transmission Line Idaho Power Company

Noss, R. F., E. T. LaRoe, and J. M. Scott. 1995. Endangered ecosystems of the United States: a preliminary assessment of loss and degradation. USDI Nat. Biol. Serv. Biol. Rep. 28. Washington, D.C.

Ohmart, R. D. and B. W. Anderson. 1996. Riparian habitat. Pages 169−200 in: A. Y. Cooperrider, R. J. Boyde, and H. R. Stuart (eds.). Inventory and monitoring of wildlife habitat. USDI Bur. Land Manage. Serv. Cen., Denver, CO.

Olson, B. E. 1999. Grazing and weeds, p. 69−72. In: R. L. Sheley and J. K. Petroff (eds.). Biology and management of noxious rangeland weeds. Oregon State Univ. Press, Corvallis.

Oregon Department of Agriculture (ODA). 2001. Oregon noxious weed strategic plan: comprehensive guide for the protection of Oregon’s resources. ODA, Salem. 60 p.

Oregon Natural Heritage Program (ORNHP). 1996. The biological and conservation data system, element occurrence record digital data set. ORNHP, Portland.

Oregon Natural Heritage Program (ORNHP). 1998. The biological and conservation data system, element occurrence record digital data set. ORNHP, Portland.

Oregon Natural Heritage Program (ORNHP). 2001a. Rare, threatened and endangered plants and animals of Oregon. ORNHP, Portland, Ore. 94 p.

Oregon Natural Heritage Program (ORNHP). 2001b. The Biological and Conservation Data System, element occurrence record digital data set. ORNHP, Portland, Ore.

Ostfeld, R. S. and C. D. Canham. 1993. Ecological perspectives on tree invasion in rights-of-way: effects of herbivory by mammals. Pages 159−164 in: Proceedings—Fifth international symposium on environmental concerns in rights-of-way management, September 19−22, 1993, Montréal, Québec, Canada.

Palik, B. J. and P. G. Murphy. 1990. Disturbance versus edge effects in sugar-maple/beech forest fragments. For.st Ecol. and Manage. 32:187−202.

Parks, C. G., E. L. Bull, and T. R. Torgersen. 1997. Field guide for the identification of snags and logs in the interior Columbia River basin. USDA For. Serv., Pacific Northwest Res. Sta., Portland, OR. PNW-GTR-390. 40 p.

Peters, E. F. and S. C. Bunting. 1994. Fire conditions pre- and postoccurrence of annual grasses on the Snake River Plain. Pages 31−36 in: S. B. Monsen and S. G. Kitchen (comps.). Proceedings—Ecology and management of annual rangelands. Gen. Tech. Rep. INT- GTR-313. USDA For. Serv., Intermountain Res. Sta., Ogden, Ut.

Piper, G. L. 1999. St. Johnswort. Pages - in: R. L. Sheley and J. K. Petroff (eds.). Biology and management of noxious rangeland weeds. Oregon State Univ. Press, Corvallis.

Page 110 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line

Quigley, T. M. and S. J. Arbelbide. 1997. An assessment of ecosystem components in the interior Columbia basin and portions of the Klamath and Great Basins. 4 volumes. Gen. Tech. Rep. PNW-GTR-405. USDA For. Serv., Pacific Northwest Res. Sta., Portland, OR.

Ranney, J. W., M. C. Bruner, and J. B. Levenson. 1981. The importance of edge in the structure and dynamics of forest islands. Pages 67-95 in: R. L. Burgess and D. M. Sharp (eds.). Forest island dynamics in a man-dominated landscape. Springer-Verlag, New York.

Raynor, G. S. 1971. Wind and temperature structure in a coniferous forest and a contiguous field. For. Sci. 17:351−363.

Rice, P. M. 2001. INVADERS database system. Div. Biol. Sci., Univ. Montana, Missoula. . Accessed on December 14, 2001.

Roché, B. F. and C. T.Roché. 1999. Diffuse knapweed. Pages 217−230 in: R. L. Sheley and J. K. Petroff (eds.). Biology and management of noxious rangeland weeds. Oregon State Univ. Press, Corvallis. 438 p.

Redmond, R. L., Z. Ma, T. P. Tady, J. C. Winne, J. Schumacher, J. Troutwine, and S. W. Holloway. 1996. Mapping existing vegetation and land cover across western Montana and northern Idaho. Wildl. Spatial Analysis Lab, Univ. Montana, Missoula.

Russell, F. L., D. B. Zippin, and N. L. Fowler. 2001. Effects of white-tailed deer (Odocoileus virginianus) on plants, plant populations and commuities: a review. Amer. Midl. Natur. 146:1−26.

Science Applications International Corporation (SAIC) and Spatial Dynamics. 2000. An evaluation of avian electrocution at transmission lines associated with the Hells Canyon Hydroelectric Complex. In: Technical appendices for new license application: Hells Canyon Hydroelectric Project. Idaho Power, Boise, ID. Technical Report E.3.2−19.

Saunders, S. C., J. Q. Chen, T. R. Crow, and K. D. Brosofske. 1998. Hierarchical relationships between landscape structure and temperature in a managed forest landscape. Landscape Ecology 13(6):381−95.

Sheley, R. L. and J. Stivers. 1999. Whitetop. Pages 401−407 in: R. L. Sheley and J. K. Petroff (eds.). Biology and management of noxious rangeland weeds. Oregon State Univ. Press, Corvallis.

Sheley, R. L. and J. K. Petroff (eds.). 1999. Biology and management of noxious rangeland weeds. Oregon State Univ. Press, Corvallis. 438 p.

Sheley, R. L., J. M. Hudak, and R. T. Grubb. 1999b. Rush skeletonweed. Pages 308−314 in: R. L. Sheley and J. K. Petroff (eds.). Biology and management of noxious rangeland weeds. Oregon State Univ. Press, Corvallis.

Hells Canyon Complex Page 111 Effects of Road and Transmission Line Idaho Power Company

Sheley, R. L., J. S. Jacobs, and M. L. Carpinelli. 1999c. Spotted knapweed. Pages 350-361 in: R. L. Sheley and J. K. Petroff (eds.). Biology and management of noxious rangeland weeds. Oregon State Univ. Press, Corvallis.

Sheley, R. L., M. Manoukian, and G. Marks. 1999a. Preventing noxious weed invasion. Pages 69-72 in: R. L. Sheley and J. K. Petroff (eds.). Biology and management of noxious rangeland weeds. Oregon State Univ. Press, Corvallis.

Smith, J. K. (ed.). 2000. Wildland fire in ecosystems: effects of fire on fauna. USDA For. Serv., Rocky Mountain Research Station, Ogden, Ut. Gen. Tech. Rep. RMRS-GTR-42-vol. 1. 83 p.

Stein, S. J. 1988. Explanation of the imbalanced age structure and scattered distrubution of ponderosa pine within a high-elevation mixed coniferous forest. For. Ecol. and Manage. 25:139−153.

Stribley, J. M. and J. B. Haufler. 1999. Landscape effects on cowbird occurrences in Michican: implications to research needs in forests of the inland west. Studies in Avian Biol. 18:68−72.

Thomas, J. W. (tech. ed.). 1979. Wildlife habitats in managed forests, the Blue Mountains of Oregon and Washington. USDA For. Serv. Agric. Handbook No. 553. Washington, D.C. 469 p.

Thompson, R. L., G. L. Wade, and R. A. Straw. 1996. Natural and planted flora of the Log Mountain Surface-mined Demonstration Area, Bell County. Pages 484-503 in: W. L Daniels, J. A. Burger, and C. E. Zipper (eds.). 1996 proceedings, annual meeting of the American Society for Surface Mining and Reclamation (Knoxville, Tenn., May 18−22, 1996).

Tisdale, E. W. 1979. A preliminary classification of Snake River Canyon grasslands in Idaho. Univ. Idaho, Moscow. Station Note No. 32. 8 p.

Tisdale, E. W. 1986. Canyon grasslands and associated shrublands of west-central Idaho and adjacent areas. Univ. Idaho, Moscow. Bull. No. 40. 42 p.

Tisdale, E. W. and M. Hironaka. 1981. The sagebrush-grass region: a review of the ecological literature. Univ. Idaho, Moscow. Contribution No. 209. 31 p.

Tyser, R. W. and C. A. Worley. 1992. Alien flora in grasslands adjacent to road and trail corridors in Glacier National Park, Montana, USA. Conservation Biology. 6(2):253−262.

U.S. Department of Agriculture (USDA). 1990. Final environmental impact statement, land and resource management plan. U.S. Forest Service, Pacific Northwest Region, Wallowa-Whitman National Forest, Baker, Oregon, USA.

Page 112 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line

U.S. Forest Service (USFS). 1996. Interior Columbia River basin ecosystem management Project classification of existing vegetation by broad vegetative communities. Intermountain Fire Sci. Lab, Missoula, MT.

U.S. Forest Service (USFS). 1999. Hells Canyon National Recreation Area comprehensive management plan. Draft Environmental Impact Statement. USDA For. Serv., Pacific Northwest Region, Wallowa-Whitman Nat. For.

Vasek, F. C., H. B. Johnson, and G. D. Brum. 1975. Effects of power transmission lines on vegetation of the Mojave Desert. Madroño 23:114−130.

Wales, B. 1972. Vegetation analysis of north and south edges in a mature oak-hickory forest. Ecol. Monogr. 42:451−471.

Wallowa-Whitman National Forest (WWNF). 1999. GIS vegetation coverage. Baker City, OR.

Washington State Noxious Weed Control Board. 2001. Houndstongue. . Accessed on December 19, 2001.

Water Resources Climate Center (WRCC). 1998. Climatological data summaries. . Accessed on June 29, 1999.

Welsh, S. L., N. D. Atwood, S. Goodrich, and L. C. Higgins. 1987. A Utah flora. Nat. Memoirs No. 9. Brigham Young Univ. Press, Provo, UT. 894 p.

Whisenant, S. G. 1990. Changing fire frequencies on Idaho's Snake River Plains: ecological and management implications. Pages 4−11 in: E. D. McArthur, E. M. Romney, S. D. Smith, and P. T. Tueller (comps.). Proceedings—Symposium on cheatgrass invasion, shrub die- off, and other aspects of shrub biology and management. Gen. Tech. Rep. INT-276. USDA For. Serv., Intermountain Res. Sta., Ogden, UT.

Whitney, G. G. and J. R. Runkle. 1981. Edge versus age effects in the development of a beech- maple forest. Oikos 37:377−381.

Williams-Linera, G. 1990. Vegetation structure and environmental conditions of forest edges in Panama. J. Ecology 78:356−373.

Whitson T. D., L. C. Burrill, S. A. Dewey, D. W. Cudney, B. E. Nelson, R. D. Lee, and R. Parker. 1999. Weeds of the West: 8th edition. Grand Teton Lithography, Jackson, WY.

Whitson T. D., L. C. Burrill, S. A. Dewey, D. W. Cudney, B. E. Nelson, R. D. Lee, and R. Parker. 2000. Weeds of the West: 9th edition. Grand Teton Lithography, Jackson, WY.

Hells Canyon Complex Page 113 Effects of Road and Transmission Line Idaho Power Company

William, R. D., D. Bal, T. Miller, R. Parker, J. P. Yenish, T. W. Miller, G. A. Lee, and D. Morishita (comps.). 1999. Pacific Northwest weed control handbook. Oregon State Univ., Corvallis. 380 p.

Yuguang, B, A. Zoheir, and R. E. Redmann. 2001. Relationship between plant species diversity and grassland condition. J. Range Manage. 54(2):177−183.

Page 114 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line

Table 1. Transmission lines to be relicensed with the Hells Canyon Complex.

Right-of- Way Width Line Line Name Location kV Km Structure Type (m) Brownlee Dam to 903 Brownlee to Quartz Jct. Quartz Junction (Baker) 230 74 H-Frame Wood 46 Brownlee to Brownlee Dam to 904 Boise Bench #1 and #2 Boise Bench Substation 230 161 Steel Lattice 46 905 Brownlee to Oxbow Brownlee Dam to Oxbow Dam 230 18 Steel Lattice 46 Boise Bench to Midpoint 906 Boise Bench to Midpoint #2 Substation 230 169 H-Frame Wood 46 Oxbow to Lolo and Oxbow Dam to Pallette 907 Brownlee Junction 230 34 Steel Lattice 30 908 Oxbow to Lolo Pallette Junction to Imnaha 230 39 H-Frame Wood 30 Brownlee to Hells Canyon and Hells Canyon to Hells Canyon Dam to Pallette 910 Hurricane Junction 230 13 Steel Lattice 30 Brownlee to Brownlee Dam to 911 Boise Bench #3 and #4 Boise Bench Substation 230 164 Steel Lattice 30 Boise Bench Substation to H-Frame 912 Boise Bench to Midpoint #3 Midpoint Substation 230 171 Wood/Laminate 46 913 Hells Canyon to Hurricane Pallette Jct. to Enterprise, OR 230 47 H-Frame Wood 30 923 Borah to Brady #2 Borah to Brady 230 6 H-Frame Wood 46 Pine Creek-Oxbow Tap-Ballard Park-Lime Point Creek-Big Bar-Eagle Bar- 945 Pine Creek to Hells Canyon Hells Canyon Big Bar Tap 69 35 Single Pole Wood 15 Midpoint Tap to Adelaide Tap 951 Midpoint to Borah #2 to Borah 345 125 H-Frame Wood 46 952 Adelaide Tap Midpoint Tap to Borah #1 345 5 H-Frame Laminate 15

Hells Canyon Complex Page 115 Effects of Road and Transmission Line Idaho Power Company

Table 2. Linear length (Kilometers) of land ownership in Hells Canyon Complex transmission-line rights-of-way.

Bureau of Line Land US Forest Bureau of State Number Line Length Managemen Service Reclamation of Idaho Private Miscellaneous 903 74.0 33.6 0 0 0 40.2 0.2 904 160.7 36.4 1.1 0.8 24.6 97.2 0.6 905 17.2 7.1 0 0 4.5 5.3 0.3 906 168.9 87.1 0 0.6 4.0 77.2 0 907 32.9 8.5 16.7 0 0 7.4 0.3 908 39.6 0 6.3 0 0 33.3 0 910 13.2 0 12.7 0 0 0.5 0 911 164.7 38.3 2.9 0.2 25.6 97.4 0.3 912 171.1 110.1 0 3.2 9.8 48.0 0 913 46.7 0 13.5 0 0 33.2 0 923 6.5 0 0 0 0.2 6.1 0.2 945 34.9 7.2 25.3 0 0 2.4 0 951 125.2 72.7 0 5.6 3.4 43.3 0.2 952 5.8 0 0 0 0 5.8 0 All lines 1061.4 401.0 78.5 10.4 72.1 497.3 2.1

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Table 3. Kilometers of Hells Canyon Complex transmission-line service roads on public land and portions that were surveyed and those that were not surveyed (subsampled or missed).

Not Surveyed Line but Total not Number Service Roads Surveyed Units Subsampled Missed Surveyed 903 70 67 0 3 3 904 85 78 6 1 7 905 27 27 0 0 0 906 103 59 41 3 44 907 31 30 0 1 1 908 10 10 0 0 0 910 11 9 0 2 2 911 97 76 0 21 21 912 159 77 64 18 82 913 17 17 0 0 0 951 82 18 64 0 64

Totals: 692 468 175 49 224

Hells Canyon Complex Page 117 Effects of Road and Transmission Line Idaho Power Company

Table 4. Linear length (Kilometers) of cover types on public and IPC lands in the Hells Canyon Complex transmission-line rights-of-way.

Transmission Line Number Cover Type All 903 904 905 906 907 908 910 911 912 913 923 945 951 Big Sagebrush 152.9 14.6 9.3 49.0 8.4 56.3 0.1 0.1 15.1 Perennial Grassland 144.4 10.8 20.6 5.6 10.6 6.2 3.9 5.6 27.8 11.0 4.6 0.7 37.0

Annual Grass 118.6 5.5 21.5 3.4 27.2 0.8 13.7 31.9 14.6 Herb Burn 36.7 1.0 3.7 21.7 10.3 Disturbed 31.5 0.1 0.2 31.1 Bitterbrush 26.7 0.2 6.7 3.0 6.5 10.1 0.2 Montane Shrub 20.2 1.8 6.2 0.8 4.5 3.3 3.6 Douglas-Fir 4.9 1.7 0.9 0.7 1.5 Dry Meadow 4.5 2.1 2.4 Riverine 4.3 2.7 0.3 1.2 0.1 Riparian Low Sage 3.9 0.4 2.6 0.8 Rabbitbrush 3.2 0.5 0.9 1.9 Water 3.2 0.1 0.7 0.6 0.4 0.1 0.2 0.1 0.7 0.2 Alpine Shrub 1.9 0.7 1.2 Shrub Riparian 1.6 0.2 1.3 Barren Land 1.4 0.2 0.1 1.0 Douglas-Fir / 1.2 0.3 0.8 Ponderosa Pine

Ponderosa Pine 1.0 0.8 0.2 Wet Meadow 1.1 0.4 0.6 White Fir 1.0 1.0 Grand Fir 1.0 0.5 0.5 Rock 1.7 1.0 0.8 Salt-desert 0.5 0.5 Shrub Herbaceous 0.1 0.1 Riparian Total Km 567.6 32.7 63.7 12.8 91.8 29.1 5.8 12.8 67.5 123.1 14.3 0.4 33.4 80.2

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Table 5. Proportion (%) of cover types on public and IPC lands traversed by the Hells Canyon Complex transmission lines.

Transmission Line Number

Cover Type All 903 904 905 906 907 908 910 911 912 913 923 945 951

Big Sagebrush 26.9 44.7 14.6 53.4 12.4 45.7 0.1 33.9 0.2 18.8

Perennial Grassland 25.4 32.9 32.4 44.1 11.6 21.3 66.0 43.8 41.3 8.9 32.0 2.0 46.2

Annual Grass 20.9 16.9 33.8 26.6 29.7 2.8 20.2 25.9 18.2

Herb Burn 6.5 3.0 4.0 17.6 12.9

Disturbed 5.6 0.1 1.7 93.3

Bitterbrush 4.7 0.6 10.6 23.3 22.5 14.9 0.1

Montane Shrub 3.6 2.9 21.1 13.4 35.0 5.0 25.4

Douglas-Fir 0.9 5.9 16.2 5.4 10.8

Dry Meadow 0.8 7.3 16.5

Riverine Riparian 0.8 9.4 4.4 1.7 20.5

Low Sage 0.7 1.4 4.2 1.3

Rabbitbrush 0.6 0.5 0.7 2.4

Water 0.6 0.4 1.1 4.3 1.5 0.2 0.2 35.8 2.1 0.3

Alpine Shrub 0.3 2.4 8.6

Shrub Riparian 0.3 1.8 0.3 1.9 0.1

Barren Land 0.2 0.2 0.1 9.8 1.2 Douglas- Fir/Ponderosa Pine 0.2 0.5 1.2

Ponderosa Pine 0.2 2.6 1.3 0.1

Wet Meadow 0.2 1.4 0.5

White Fir 0.2 7.9

Grand Fir 0.2 1.9 3.2

Rock 0.3 7.5 2.3

Salt-desert Shrub 0.1 0.5

Herbaceous Riparian 0 0.4

Hells Canyon Complex Page 119 Effects of Road and Transmission Line Idaho Power Company

Table 6. Proportion (%) of grouped Idaho GAP cover types in the Hells Canyon Complex 10-km wide transmission lines corridor and associated landscape regions.

Landscape Regions

Wallowa Oregon Oregon Whitman Idaho Snake Snake Upper Plateau/ National Canyon/ Payette River River Grouped Cover Type Corridor Plateau Canyon Forest Mountain Valley Plateau Plain Perennial Grass 25.8 13.6 12.6 31.0 33.7 30.3 24.3 26.8 Big Sagebrush 25.5 69.2 0.6 1.5 17.2 40.1 26.1 Agricultural 14.9 17.8 10.6 0.1 0.3 6.6 5.6 36.6 Bitterbrush 6.8 -a - - 9.7 19.5 5.9 - Dry Forest 6.0 16.5 0.9 35.9 30.2 2.6 0.1 Annual Grass/Forb 5.1 38.1 0.2 5.8 4.5 1.3 Low Sagebrush 3.2 3.3 7.5 1.9 2.3 Wet Forest 2.0 0.7 25.9 2.6 0.1 Rabbitbrush 1.8 - - 6.4 2.4 Montane Shrub 1.6 - - 4.1 8.3 2.9 0.2 Riparian 1.4 - 4.2 0.9 2.3 2.0 0.8 0.4 Burned Herbaceous 1.4 2.1 - 7.3 Water 1.0 0.2 1.4 - 2.8 0.5 0.4 1.9 Perennial Grass 1.0 12.4 1.1 0.1 0.8 0.2 High Density Urban 0.7 0.7 2.3 0.3 Mountain Big Sage 0.6 1.7 1.9 - Lava 0.4 1.4 Salt Desert Shrub 0.3 0.1 1.4 - Burned Shrub 0.2 - 0.9 Rock 0.1 - - 1.0 0.2 - Low Density Urban 0.1 0.1 - 0.1 Wetland 0.1 - 0.1 - 0.1 Dry Meadow 0.1 0.1 0.1 - - Lodgepole pine - - 0.3 0.2 - Wet meadow - - - 0.1 High disturbed - - - - 0.1 Aspen - - 0.1 Low disturbed - - - - Barren - - - - Juniper - - Alpine shrub - - Tall forb montane - - a Cover types contributing less than 0.1%

Page 120 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line

Table 7. Frequency of rare plant occurrences within the road, within the 50-m buffer zone and beyond the buffer zone of Hells Canyon Complex transmission- line service roads.

Frequency of Occurrencesa Number of Species Occurrences In Service Road Within 50-m Buffer Beyond Buffer Allium aaseae 3 1 2 0 Astragalus atratus var. inseptus 19 12 19 4 Astragalus atratus var. owyheensis 4 1 4 0 Astragalus purshii var. ophiogenes 2 1 2 0 Bolandra oregana 1 0 1 0 Carex backii 10 6 8 0 Mimulus clivicola 1 0 1 0 Rubus bartonianus 10 8 10 5 Stylocline filaginia 13 9 11 2 a Larger occurrences often span more than one location category

Table 8. Occurrence summaries and community distributions for Allium aaseae located during surveys of Hells Canyon Complex transmission-line service roads.

Occurrence Unit Occurrence Number of Abundance Abundance in Abundance Number Number Size Plants in Roadwaya Buffer Zonea Beyond Buffera

1 904-367-A1 20 x 10 m 25 -- LR -- 2 904-369-A1 30 x 20 m ~100 -- LA -- 3 904-371-A1 50 x 100 m ~125 LR -- -- a Abundance: R = rare; LR = locally rare; O = occasional; LO = locally occasional; F = frequent; LF = locally frequent; A = abundant; LA = locally abundant. A “—“ indicates not present.

Table 9. Disturbance intensitiesa for units associated with Allium aaseae occurrences located during surveys of Hells Canyon Complex transmission-line service roads.

Occurrence Unit Non-project Road Service Water Number Number Agriculture Fire Livestock Roads Recreation Use Roads Erosion 1 904-367-A1 3 — 3 4 — 3 3 — 2 904-369-A1 — 2 2 — — 2 2 — 3 904-371-A1 — 2 2 — 1 2 2 1 a Disturbance intensities: 1 = slight; 2 = moderate; 3 = high; 4 = extreme. A “—“ indicates not present.

Hells Canyon Complex Page 121 Effects of Road and Transmission Line Idaho Power Company

Table 10. Occurrence summaries and community distributions for Astragalus atratus var. inseptus located during surveys of Hells Canyon Complex transmission-line service roads.

Occurrence Associated Occurrence Number Abundance Abundance in Abundance Number Unit Size of Plants in Roadwaya Buffer Zonea Beyond Buffera 1 906-248-A1 0.4–0.8 km >1000 O F — 2 906-258-A1 N/A N/A R O — 3 906-263-A1 N/A N/A — R — 4 906-463-A1 N/A 150 — LO LO 5 906-464-A1 60 x 600 m ~700 LO O — 6b 906-477-A1 N/A 30 — R — 6b 906-480-A1 N/A N/A R R R 7 906-488-A1 N/A ~400 — LO LO 8b 906-494-A2 N/A 15 — LR — 8b 906-496-A1 N/A N/A — LR — 9 912-200-A1 100 x 300 m ~500 LO LF — 10 912-211-A1 N/A ~500 LO LF — 11 912-344-A1 N/A ~600 O F — 12 912-345-A1 N/A N/A LO F — 13 912-355-A1 10 x 10 m ~200 LO LF — 14 912-373-A1 N/A N/A — LO — 15 912-378-A1 200 x 200 m ~400 — LF — 16 912-394-A1 N/A ~500 LR LF LF 17 912-395-A1 N/A N/A — LO — 18 912-517-A1 100 x 150 m ~700 LR LF — 19 912-522-A1 N/A N/A LO LF — a Abundance: R = rare; LR = locally rare; O = occasional; LO = locally occasional; F = frequent; LF = locally frequent; A = abundant; LA = locally abundant. A “—“ indicates not present. b Occurrence associated with more than one unit.

Page 122 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line

Table 11. Disturbance intensitiesa for units associated with Astragalus atratus var. inseptus occurrences located during surveys of Hells Canyon Complex transmission-line service roads.

Off- Non- Occurrence Unit Big Highway Project Service Road Water Number Number Agriculture Game Fire Livestock Vehicles Roads Roads Use Erosion

1 906-248-A1 — 1 — 2 1 — 2 1 — 2 906-258-A1 — 1 1 1 1 2 2 1 — 3 906-263-A1 — 1 — 1 1 2 2 1 — 4 906-463-A1 — 2 3 2 1 — 2 2 — 5 906-464-A1 1 2 2 2 1 1 2 1 1 6b 906-477-A1 — — — 2 — 1 1 — 6b 906-480-A1 — — — 3 — 1 1 — 7 906-488-A1 — 1 1 2 2 1 2 2 1 8b 906-494-A2 — — — 2 — 1 1 — 8b 906-496-A1 — — — 3 1 2 2 — 9 912-200-A1 — 1 — 1 1 — 2 2 2 10 912-211-A1 — 2 3 1 1 1 1 2 1 11 912-344-A1 — 2 — 1 — 2 1 3 12 912-345-A1 — 1 — 1 1 1 2 2 — 13 912-355-A1 — 1 — 1 — 2 1 — 14 912-373-A1 — 2 — 3 1 1 2 2 3 15 912-378-A1 — 2 2 1 1 — 2 2 — 16 912-394-A1 — 3 — 1 1 1 2 2 1 17 912-395-A1 — 1 3 2 1 — 2 2 2 18 912-517-A1 — 1 — 2 1 — 2 3 1 19 912-522-A1 — 1 — 2 1 2 2 3 — a Disturbance intensities: 1 = slight; 2 = moderate; 3 = high; 4 = extreme. A “—“ indicates not present. b Occurrence associated with more than one unit.

Hells Canyon Complex Page 123 Effects of Road and Transmission Line Idaho Power Company

Table 12. Occurrence summaries and community distributions for Astragalus atratus var. owyheensis located during surveys of Hells Canyon Complex transmission-line service roads.

Occurrence Associated Occurrence Number Abundance Abundance in Abundance Number Unit Size of Plants in Roadwaya Buffer Zonea Beyond Buffera 1 903-030-A1 500 x 500 m >1000 — R — 2 903-030-A2 50 x 50 m ~100 — O — 3 903-033-A1 50 x 50 m ~100 — O — 4 903-102-A1 250 x 500 m ~300 O O — a Abundance: R = rare; LR = locally rare; O = occasional; LO = locally occasional; F = frequent; LF = locally frequent; A = abundant; LA = locally abundant. A “—“ indicates not present.

Table 13. Disturbance intensitiesa for units associated with Astragalus atratus var. owyheensis occurrences located during surveys of Hells Canyon Complex transmission-line service roads.

Occurrence Unit Big Non-Project Service Road Water Number Number Game Livestock Roads Roads Use Erosion 1 903-030-A1 1 1 1 2 2 1 2 903-030-A2 1 1 — — — — 3 903-033-A1 1 1 — 1 1 1 4 903-102-A1 1 1 — 1 1 — a Disturbance intensities: 1 = slight; 2 = moderate; 3 = high; 4 = extreme. A “—“ indicates not present.

Table 14. Occurrence summaries and community distributions for Astragalus purshii var. ophiogenes located during surveys of Hells Canyon Complex transmission-line service roads.

Occurrence Associated Occurrence Number Abundance Abundance in Abundance Number Unit Size of Plants in Roadwaya Buffer Zonea Beyond Buffera 1 912-621-A1 100 x 50 m ~50 LR LO — 2 912-621-A1 20 x 10 m 12 — LO — a Abundance: R = rare; LR = locally rare; O = occasional; LO = locally occasional; F = frequent; LF = locally frequent; A = abundant; LA = locally abundant. A “—“ indicates not present.

Page 124 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line

Table 15. Disturbance intensitiesa for units associated with Astragalus purshii var. ophiogenes occurrences located during surveys of Hells Canyon Complex transmission-line service roads.

Occurrence Number Unit Number Livestock Road Use Service Roads 1 912-621-A1 4 2 2 2 912-621-A1 4 2 2 a Disturbance intensities: 1 = slight; 2 = moderate; 3 = high; 4 = extreme.

Table 16. Occurrence summaries and community distributions for Bolandra oregana located during surveys of Hells Canyon Complex transmission-line service roads.

Occurrence Associated Occurrence Number Abundance Abundance in Abundance Number Unit Size of Plants in Roadwaya Buffer Zonea Beyond Buffera 1 908-147-A1 5 x 5 m 25 — LR — a Abundance: R = rare; LR = locally rare; O = occasional; LO = locally occasional; F = frequent; LF = locally frequent; A = abundant; LA = locally abundant. A “—“ indicates not present.

Table 17. Disturbance intensitiesa for units associated with Bolandra oregana occurrences located during surveys of Hells Canyon Complex transmission-line service roads.

Occurrence Number Unit Number Livestock Road Use Service Roads Water Erosion 1 908-147-A1 3 2 2 2 a Disturbance intensities: 1 = slight; 2 = moderate; 3 = high; 4 = extreme.

Hells Canyon Complex Page 125 Effects of Road and Transmission Line Idaho Power Company

Table 18. Occurrence summaries and community distributions for Carex backii located during surveys of Hells Canyon Complex transmission-line service roads.

Occurrence Associated Occurrence Number Abundance Abundance in Abundance Number Unit Size of Plants in Roadwaya Buffer Zonea Beyond Buffera 1 907-042-A1 N/A ~800 LA — — 2 907-084-C1 5 x 5 m 3 — LO — 3b 907-093-A1 200 x 50 m ~100 — LO — 3b 907-094-A1 N/A N/A — LO — 3b 907-095-C1 N/A N/A — LO — 4 907-100-C1 2x5 m 5 LO O — 5 907-100-C1 N/A 1 LO O — 6 907-102-A1 2 x 5 m 15 LF — — 7 907-102-A1 N/A N/A LF — — 8 908-126-A2 N/A 1 — LR — 9 908-147-A1 3 x 5 m 3 — LR — 10 910-141-A1 5 x 20 m 5 R — — a Abundance: R = rare; LR = locally rare; O = occasional; LO = locally occasional; F = frequent; LF = locally frequent; A = abundant; LA = locally abundant. A “—“ indicates not present. b Occurrence associated with more than one unit.

Table 19. Disturbance intensitiesa for units associated with Carex backii occurrences located during surveys of Hells Canyon Complex transmission-line service roads.

Off- Non- Occurrence Unit Big Corridor Highway Project Service Road Water Number Number Game Clearing Fire Industry Livestock Logging Vehicles Roads Road Use Erosion 1 907-042-A1 3 — 2 — 3 — 2 — 2 2 1 2 907-084-C1 1 2 — 2 — — — — — 1 2 3 907-093-A1 — 3 — — 1 1 — 1 3 1 1 3b 907-094-A1 1 — — — — — — — 2 1 2 3b 907-095-C1 1 3 — — — — — 2 — — 2 4 907-100-C1 1 2 — — — — — — — — — 5 907-100-C1 1 2 — — — — — — — — — 6 907-102-A1 1 — — — — — — 1 2 1 2 7 907-102-A1 1 — — — — — — 1 2 1 2 8 908-126-A2 — — — — 2 — — 1 2 2 1 9 908-147-A1 — — — — 3 — — — 2 2 — 10 910-141-A1 1 — — — — 2 — 1 3 2 — a Disturbance intensities: 1 = slight; 2 = moderate; 3 = high; 4 = extreme. A “—“ indicates not present. b Occurrence associated with more than one unit.

Page 126 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line

Table 20. Occurrence summaries and community distributions for Mimulus clivicola located during surveys of Hells Canyon Complex transmission-line service roads.

Occurrence Associated Occurrence Number Abundance Abundance in Abundance Number Unit Size of Plants in Roadwaya Buffer Zonea Beyond Buffera 1 907-084-C1 1 X 10 m ~200 — LF — a Abundance: R = rare; LR = locally rare; O = occasional; LO = locally occasional; F = frequent; LF = locally frequent; A = abundant; LA = locally abundant. A “—“ indicates not present.

Table 21. Disturbance intensitiesa for units associated with Mimulus clivicola located during surveys of Hells Canyon Complex transmission-line service roads.

Occurrence Corridor Water Number Unit Number Big Game Clearing Industry Road Use Erosion 1 907-084-C1 1 2 2 1 2 a Disturbance intensities: 1 = slight; 2 = moderate; 3 = high; 4 = extreme.

Table 22. Occurrence summaries and community distributions for Rubus bartonianus located during surveys of Hells Canyon Complex transmission-line service roads.

Occurrence Associated Occurrence Number Abundance Abundance in Abundance

Number Unit Size of Plants in Roadwaya Buffer Zonea Beyond Buffera 1 945-225-A1 1000 x 200 m 50 O O — 2 945-235-A1 N/A N/A — F F 3 945-250-A1 N/A N/A — LF — 4 945-265-A1 350 x 150 m 200 F F F 5b 945-280-A1 N/A N/A LR LF LR 5b 945-285-A1 N/A N/A F F F 6b 945-290-A1 N/A N/A LF — — 6b 945-295-A1 N/A N/A — LR LR 6b 945-300-A1 N/A N/A — — LR 7b 945-305-A1 N/A N/A — F F 7b 945-310-A1 N/A N/A LR LF — 8b 945-315-A1 N/A N/A LR LF — 8b 945-320-A1 N/A N/A LR LR — 9 945-325-A1 N/A N/A LR LR — 10 945-330-A1 N/A N/A LF LF — a Abundance: R = rare; LR = locally rare; O = occasional; LO = locally occasional; F = frequent; LF = locally frequent; A = abundant; LA = locally abundant. A “—“ indicates not present. b Occurrence associated with more than one unit.

Hells Canyon Complex Page 127 Effects of Road and Transmission Line Idaho Power Company

Table 23. Disturbance intensitiesa for units associated with Rubus bartonianus occurrences located during surveys of Hells Canyon Complex transmission-line service roads.

Occurrence Unit Big Water Number Number Game Fire Industry Livestock Recreation Erosion 1 945-225-A1 1 — 2 — 1 2 2 945-235-A1 2 — — 1 — 3 3 945-250-A1 1 — — — — 3 4 945-265-A1 1 1 — — — 2 5b 945-280-A1 — — — — — 2 5b 945-285-A1 1 — — — — 2 6b 945-290-A1 — — — — — — 6b 945-295-A1 — — — — — — 6b 945-300-A1 — — 1 — — — 7b 945-305-A1 — — 3 — — — 7b 945-310-A1 — — — — — — 8b 945-315-A1 — — 1 — — — 8b 945-320-A1 — — 1 — — — 9 945-325-A1 — — 2 — — — 10 945-330-A1 — — 3 — — — a Disturbance intensities: 1 = slight; 2 = moderate; 3 = high; 4 = extreme. A “—“ indicates not present. b Occurrence associated with more than one unit.

Page 128 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line

Table 24. Occurrence summaries and community distributions for Stylocline filaginea located during surveys of Hells Canyon Complex transmission-line service roads.

Occurrence Associated Occurrence Number of Abundance in Abundance in Abundance Number Unit Size Plants Roadwaya Buffer Zonea Beyond Buffera

1 904-154-A1 50 x 100 m ~500 — LO — 2 904-165-A1 20 x 40 m >1000 LF LO — 3 906-111-A1 10 x 70 m ~300 — LO LO 4 906-263-A1 100 x 500 m >1000 LF LF — 5 906-279-A1 1 x 1 m 92 — R — 6 906-464-A1 60 x 600 m >10,000 LO LF — 7 906-516-A1 50 x 50 m >5,000 LA LA — 8 906-534-A1 100 x 400 m >5,000 LF LF LF 9 906-537-A1 50 x 50 m ~500 LO LO — 10 911-101-A1 200 x 200 m >5,000 LO LO — 11 911-181-A1 3 x 50 m ~500 LO — — 12 911-249-A1 20 x 20 m ~500 LO — — 13 912-344-A1 15 x 15 m ~50 — LF — a Abundance: R = rare; LR = locally rare; O = occasional; LO = locally occasional; F = frequent; LF = locally frequent; A = abundant; LA = locally abundant. A “—“ indicates not present.

Table 25. Disturbance intensitiesa for units associated with Stylocline filaginia occurrences located during surveys of Hells Canyon Complex transmission-line service roads.

Occurrence Unit Big Off-Highway Non-Project Service Road Water Number Number Agriculture Game Fire Livestock Vehicles Roads Road Use Erosion 1 904-154-A1 — 1 — 1 — 1 2 1 3 2 904-165-A1 — 1 1 1 — — 1 1 2 3 906-111-A1 — 1 2 3 — 1 1 1 — 4 906-263-A1 — 1 — 1 1 2 2 1 — 5 906-279-A1 — 1 4 2 1 1 1 1 — 6 906-464-A1 1 2 2 2 1 1 2 1 1 7 906-516-A1 — 2 2 1 1 1 2 2 1 8 906-534-A1 — 2 2 2 1 — 1 1 — 9 906-537-A1 — 2 2 2 1 — 1 1 — 10 911-101-A1 — 1 — 2 1 1 2 2 2 11 911-181-A1 — 2 — 2 — — 2 2 2 12 911-249-A1 — 2 2 2 1 — 2 2 2 13 912-344-A1 — 2 — 1 — — 2 1 3 a Disturbance intensities: 1 = slight; 2 = moderate; 3 = high; 4 = extreme. A “—“ indicates not present.

Hells Canyon Complex Page 129 Effects of Road and Transmission Line Idaho Power Company

Table 26. Number of units containing records of each of the noxious weed species located during surveys of Hells Canyon Complex transmission-line service roads.

Number of Units Latin Binomial Common Name with Species Records Chondrilla juncea rush skeletonweed 212 Cynoglossum officinalea houndstongue 160 Onopordum acanthium Scotch thistle 157 Cardaria draba whitetop 146 Cirsium arvense Canada thistle 101 Convolvulus arvensis field bindweed 75 Hypericum perforatuma St. Johnswort 69 Taeniatherum caput-medusaea medusahead rye 64 Rumex crispusa curly dock 41 Dipsacus sylvestrisa common teasel 39 Centaurea diffusa diffuse knapweed 29 Conium maculatum poison hemlock 10 Euphorbia esula leafy spurge 7 Centaurea repens Russian knapweed 3 Aegilops cylindrica jointed goatgrass 2 Tribulus terrestris puncturevine 2 Centaruea maculosa spotted knapweed 1 a Considered noxious only in Oregon.

Page 130 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line

Table 27. Number of units, per line, containing each of the 17 noxious weed species located during surveys of Hells Canyon Complex transmission-line service roads.

Line Number

Species 903 904 905 906 907 908 910 911 912 913 951

Aegilops cylindrica 0 2 0 0 0 0 0 0 0 0 0 Cardaria draba 61 57 10 1 1 0 0 13 3 0 0 Centaurea diffusa 2 1 0 4 10 4 2 0 4 2 0 Centaurea maculosa 0 0 0 0 0 0 0 1 0 0 0 Centaurea repens 0 0 0 0 1 0 0 0 0 2 0 Chondrilla juncea 0 53 0 31 0 0 0 70 58 0 0 Cirsium arvense 4 5 1 2 41 4 8 1 1 34 0 Conium maculatum 0 5 1 0 0 0 0 4 0 0 0 Convolvulus arvensis 18 22 2 2 10 7 0 10 4 0 0 Cynoglossum officinale 8 0 1 0 74 19 14 0 0 44 0 Dipsacus sylvestris 15 0 0 0 4 18 0 0 0 2 0 Euphorbia esula 0 3 0 0 0 0 0 4 0 0 0 Hypericum perforatum 9 0 1 0 33 18 5 0 0 3 0 Onopordum acanthium 40 33 43 1 13 9 0 16 1 0 1 Rumex crispus 19 0 0 0 7 11 0 0 0 4 0 Taeniatherum caput-medusae 55 0 1 0 6 1 0 0 0 1 0 Tribulus terrestris 1 0 1 0 0 0 0 0 0 0 0

Hells Canyon Complex Page 131 Effects of Road and Transmission Line Idaho Power Company

Table 28. Summary of activity types on 146 Hells Canyon Complex transmission-line service road survey units containing Cardaria draba.

Number Number of Survey Units by of Units Activity Level Average with Activity Activity a Activity Type Occurring 1 2 3 4 Intensity Agriculture 0 0 2 0 0 0 Big game 107 59 39 9 0 1.5 Corridor clearing 0 0 0 0 0 0 Fire 18 9 7 2 0 1.6 Industrial 4 1 1 2 0 2.8 Livestock 140 33 48 43 16 2.3 Logging 0 0 0 0 0 0 Off-highway vehicles 28 25 2 1 0 1.1 Non-project roads 36 24 7 4 1 1.5 Recreation 0 0 0 0 0 0 Residential 1 1 0 0 0 1 Road use 34 51 74 11 0 1.9 Service roads 134 34 71 27 2 1.9 Water erosion 52 20 20 10 2 1.9 a Activity intensities: 1 = slight; 2 = moderate; 3 = high; 4 = extreme.

Page 132 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line

Table 29. Summary of activity types on 29 Hells Canyon Complex transmission-line service road survey units containing Centaurea diffusa.

Number Number of Survey Units by of Units Activity Level Average with Activity Activity a Activity Type Occurring 1 2 3 4 Intensity Agriculture 2 0 0 2 0 3 Big game 12 9 3 0 0 1.3 Corridor clearing 8 1 3 4 0 2.4 Fire 5 1 2 1 1 2.4 Industrial 1 1 0 0 0 1 Livestock 25 6 10 8 1 2.2 Logging 3 1 Off-highway vehicles 7 5 1 1 0 1.3 Non-project roads 12 3 6 3 0 2 Recreation 0 0 0 0 0 0 Residential 1 1 0 0 0 1 Road use 19 3 9 7 0 1.8 Service roads 25 3 17 4 1 2.2 Water erosion 16 5 3 4 4 2.4 a Activity intensities: 1 = slight; 2 = moderate; 3 = high; 4 = extreme.

Hells Canyon Complex Page 133 Effects of Road and Transmission Line Idaho Power Company

Table 30. Summary of activity types on 212 Hells Canyon Complex transmission-line service road survey units containing Chondrilla juncea.

Number Number of Survey Units by of Units Activity Level Average with Activity Activity a Activity Type Occurring 1 2 3 4 Intensity Agriculture 4 3 0 1 0 105 Big game 160 102 55 4 0 1.4 Corridor clearing 0 0 0 0 0 0 Fire 149 39 60 42 11 2.2 Industrial 0 0 0 0 0 0 Livestock 200 56 99 39 9 2 Logging 0 0 Off-highway vehicles 117 101 16 1 0 1.2 Non-project roads 94 69 16 7 2 1.4 Recreation 4 2.3 Residential 0 0 0 0 0 0 Road use 182 54 119 9 0 1.5 Service roads 182 33 137 13 0 1.9 Water erosion 109 52 34 21 2 1.7 a Activity intensities: 1 = slight; 2 = moderate; 3 = high; 4 = extreme.

Page 134 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line

Table 31. Summary of activity types on 101 Hells Canyon Complex transmission-line service road survey units containing Cirsium arvense.

Number Number of Survey Units by of Units Activity Level Average with Activity Activity a Activity Type Occurring 1 2 3 4 Intensity Agriculture 2 0 0 2 0 3 Big game 27 22 3 2 0 1.3 Corridor clearing 66 3 15 48 0 2.7 Fire 22 19 2 1 0 1.2 Industrial 5 2 2 1 0 2 Livestock 63 23 20 16 3 2 Logging 28 2 Off-highway vehicles 7 6 1 0 0 1.1 Non-project roads 43 15 16 10 2 2 Recreation 0 0 Residential 1 0 1 0 0 2 Road use 56 13 40 3 0 1.7 Service roads 89 23 48 15 2 2 Water erosion 33 15 10 6 2 1.8 a Activity intensities: 1 = slight; 2 = moderate; 3 = high; 4 = extreme.

Hells Canyon Complex Page 135 Effects of Road and Transmission Line Idaho Power Company

Table 32. Summary of disturbance types on 10 Hells Canyon Complex transmission-line service road survey units containing Conium maculatum.

Number Number of Survey Units by of Units Activity Level Average with Activity Activity a Activity Type Occurring 1 2 3 4 Intensity Agriculture 0 0 0 0 0 0 Big game 6 3 2 1 0 1.7 Corridor clearing 0 0 0 0 0 0 Fire 3 0 1 2 0 2.7 Industrial 1 0 0 0 1 4 Livestock 10 3 4 2 1 2.1 Logging 0 0 Off-highway vehicles 2 2 0 0 0 1 Non-project roads 5 1 3 1 0 2 Recreation 0 0 Residential 2 0 0 0 0 1 Road use 10 4 5 1 0 1.7 Service roads 10 0 5 4 1 2.6 Water erosion 7 0 4 3 0 2.4 a Activity intensities: 1 = slight; 2 = moderate; 3 = high; 4 = extreme.

Page 136 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line

Table 33. Summary of activity types on 75 Hells Canyon Complex transmission-line service road survey units containing Convolvulus arvensis.

Number Number of Survey Units by of Units Activity Level Average with Activity Activity a Activity Type Occurring 1 2 3 4 Intensity Agriculture 3 3 0 0 0 1 Big game 52 29 20 3 0 1.5 Corridor clearing 0 0 0 0 0 0 Fire 18 9 7 1 1 1.7 Industrial 2 0 2 0 0 2 Livestock 73 13 21 26 14 2.6 Logging 0 0 Off-highway vehicles 24 18 6 0 0 1.2 Non-project roads 37 21 13 3 0 1.5 Recreation 3 1.7 Residential 2 1 1 0 0 1.5 Road use 74 11 55 8 0 1.9 Service roads 73 4 56 13 0 2.1 Water erosion 53 18 25 8 2 1.9 a Activity intensities: 1 = slight; 2 = moderate; 3 = high; 4 = extreme.

Hells Canyon Complex Page 137 Effects of Road and Transmission Line Idaho Power Company

Table 34. Summary of activity types on 160 Hells Canyon Complex transmission-line service road survey units containing Cynoglossum officinale.

Number Number of Survey Units by of Units Activity Level Average with Activity Activity a Activity Type Occurring 1 2 3 4 Intensity Agriculture 1 1 0 0 0 1 Big game 57 42 12 3 0 1.3 Corridor clearing 89 5 20 64 0 2.7 Fire 21 20 1 0 0 1 Industrial 6 2 3 0 1 2 Livestock 106 32 34 31 9 2.2 Logging 27 2 Off-highway vehicles 12 7 5 0 0 1.4 Non-project roads 74 26 31 14 3 1.9 Recreation 0 0 Residential 3 1 2 0 0 1.5 Road use 102 26 68 8 0 1.8 Service roads 146 30 84 30 2 2 Water erosion 64 25 28 7 4 1.8 a Activity intensities: 1 = slight; 2 = moderate; 3 = high; 4 = extreme.

Page 138 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line

Table 35. Summary of activity types on 39 Hells Canyon Complex transmission-line service road survey units containing Dipsacus sylvestris.

Number Number of Survey Units by of Units Activity Level Average with Activity Activity a Activity Type Occurring 1 2 3 4 Intensity Agriculture 0 0 0 0 0 0 Big game 21 10 10 1 0 1.6 Corridor clearing 3 0 3 0 0 2 Fire 4 2 2 0 0 1.5 Industrial 0 0 0 0 0 0 Livestock 35 6 11 8 10 2.6 Logging 2 1 Off-highway vehicles 11 7 4 0 0 1.4 Non-project roads 16 10 6 0 0 1.4 Recreation 0 0 Residential 0 0 0 0 0 0 Road use 37 2 29 6 0 2.1 Service roads 39 2 32 4 1 2.1 Water erosion 31 11 15 3 2 1.9 a Activity intensities: 1 = slight; 2 = moderate; 3 = high; 4 = extreme.

Hells Canyon Complex Page 139 Effects of Road and Transmission Line Idaho Power Company

Table 36. Summary of activity types on 7 Hells Canyon Complex transmission-line service road survey units containing Euphorbia esula.

Number Number of Survey Units by of Units Activity Level Average with Activity Activity a Activity Type Occurring 1 2 3 4 Intensity Agriculture 1 1 0 0 0 1 Big game 7 5 2 0 0 1.3 Corridor clearing 0 0 0 0 0 0 Fire 0 0 0 0 0 0 Industrial 0 0 0 0 0 0 Livestock 7 4 3 0 0 1.4 Logging 0 0 Off-highway vehicles 5 5 0 0 0 1 Non-project roads 2 2 0 0 0 1 Recreation 0 0 Residential 0 0 0 0 0 0 Road use 6 0 6 0 0 1.7 Service roads 6 1 5 0 0 1.8 Water erosion 5 2 2 1 0 1.8 a Activity intensities: 1 = slight; 2 = moderate; 3 = high; 4 = extreme.

Page 140 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line

Table 37. Summary of activity types on 69 Hells Canyon Complex transmission-line service road survey units containing Hypericum perforatum.

Number Number of Survey Units by of Units Activity Level Average with Activity Activity a Activity Type Occurring 1 2 3 4 Intensity Agriculture 0 1 0 0 0 0 Big game 29 19 7 3 0 1.4 Corridor clearing 23 2 13 8 0 2.3 Fire 8 6 2 0 0 1.3 Industrial 3 1 2 0 0 1.7 Livestock 41 8 10 9 14 2.7 Logging 4 1 Off-highway vehicles 5 2 3 0 0 1.6 Non-project roads 27 10 13 3 1 1.8 Recreation 1 1 Residential 0 0 0 0 0 0 Road use 53 13 35 5 0 1.8 Service roads 63 7 41 14 1 2.1 Water erosion 41 12 23 2 4 2 a Activity intensities: 1 = slight; 2 = moderate; 3 = high; 4 = extreme.

Hells Canyon Complex Page 141 Effects of Road and Transmission Line Idaho Power Company

Table 38. Summary of activity types on 157 Hells Canyon Complex transmission-line service road survey units containing Onopordum acanthium.

Number Number of Survey Units by of Units Activity Level Average with Activity Activity a Activity Type Occurring 1 2 3 4 Intensity Agriculture 4 1 0 3 0 1.5 Big game 117 55 45 17 0 1.7 Corridor clearing 6 1 2 3 0 2.3 Fire 17 9 4 4 0 1.7 Industrial 4 0 2 0 2 3 Livestock 145 32 47 49 17 2.4 Logging 1 1 Off-highway vehicles 38 30 7 1 0 1.2 Non-project roads 38 24 11 3 0 1.4 Recreation 1 1 Residential 1 1 0 0 0 1 Road use 143 69 62 12 0 1.5 Service roads 145 23 83 34 5 2.1 Water erosion 76 22 38 13 3 2 a Activity intensities: 1 = slight; 2 = moderate; 3 = high; 4 = extreme.

Page 142 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line

Table 39. Summary of activity types on 41 Hells Canyon Complex transmission-line service road survey units containing Rumex crispus.

Number Number of Survey Units by of Units Activity Level Average with Activity Activity a Activity Type Occurring 1 2 3 4 Intensity Agriculture 0 0 0 0 0 0 Big game 20 9 11 0 0 1.6 Corridor clearing 5 2 3 0 0 1.6 Fire 4 2 2 0 0 1.5 Industrial 0 0 0 0 0 0 Livestock 36 6 14 6 10 2.6 Logging 3 3 0 0 0 1 Off-highway vehicles 10 9 1 0 0 1.1 Non-project roads 16 10 6 0 0 1.4 Recreation 0 0 0 0 0 0 Residential 0 0 0 0 0 0 Road use 37 4 30 3 0 1.9 Service roads 38 3 30 4 1 2.1 Water erosion 31 12 16 2 1 1.7 a Activity intensities: 1 = slight; 2 = moderate; 3 = high; 4 = extreme.

Hells Canyon Complex Page 143 Effects of Road and Transmission Line Idaho Power Company

Table 40. Summary of activity types on 64 Hells Canyon Complex transmission-line service road survey units containing Taeniatherum caput-medusae.

Number Number of Survey Units by of Units Activity Level Average with Activity Activity a Activity Type Occurring 1 2 3 4 Intensity Agriculture 1 1 0 0 0 1 Big game 48 27 19 2 0 1.5 Corridor clearing 0 0 0 0 0 0 Fire 13 9 4 0 0 1.3 Industrial 1 0 1 0 0 2 Livestock 62 9 27 16 11 2.5 Logging 1 1 0 0 0 1 Off-highway vehicles 22 17 4 1 0 1.3 Non-project roads 30 20 8 2 0 1.4 Recreation 0 0 0 0 0 0 Residential 1 1 0 0 0 1 Road use 60 17 38 5 0 1.7 Service roads 60 14 40 5 1 1.9 Water erosion 38 13 18 7 0 1.8 a Activity intensities: 1 = slight; 2 = moderate; 3 = high; 4 = extreme.

Page 144 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line

Table 41. Summary of agricultural disturbance intensities along Hells Canyon Complex transmission-line service roads.

Km Km with Km with Km with Km with Km with Line Surveyed No Slight Moderate High Extreme Number per Line Disturbance Disturbance Disturbance Disturbance Disturbance 903 66.7 66.7 0.0 0.0 0.0 0.0 904 78.0 77.1 0.7 0.3 0.0 0.0 905 27.0 27.0 0.0 0.0 0.0 0.0 906 58.9 52.4 5.5 1.0 0.0 0.0 907 30.3 29.8 0.5 0.0 0.0 0.0 908 10.5 10.5 0.0 0.0 0.0 0.0 910 8.6 8.6 0.0 0.0 0.0 0.0 911 76.2 72.3 3.9 0.0 0.0 0.0 912 77.1 77.1 0.0 0.0 0.0 0.0 913 16.6 16.6 0.0 0.0 0.0 0.0 951 18.0 18.0 0.0 0.0 0.0 0.0

Total 467.8 456.0 10.5 1.3 0.0 0.0

Table 42. Summary of big game disturbance intensities along Hells Canyon Complex transmission-line service roads.

Km Km with Km with Km with Km with Km with Line Surveyed No Slight Moderate High Extreme Number per Line Disturbance Disturbance Disturbance Disturbance Disturbance 903 66.7 17.3 27.3 22.0 0.0 0.0 904 78.0 24.9 36.3 14.2 1.0 1.7 905 27.0 6.3 5.3 8.5 7.0 0.0 906 58.9 18.0 24.2 16.6 0.0 0.0 907 30.3 12.7 10.5 5.9 1.1 0.0 908 10.5 8.4 2.1 0.0 0.0 0.0 910 8.6 3.8 4.7 0.0 0.0 0.0 911 76.2 8.8 31.9 33.4 2.2 0.0 912 77.1 17.3 29.1 26.9 3.7 0.0 913 16.6 11.7 3.8 1.0 0.0 0.0 951 18.0 6.8 11.2 0.0 0.0 0.0

Total 467.8 136.0 186.5 128.6 14.9 1.7

Hells Canyon Complex Page 145 Effects of Road and Transmission Line Idaho Power Company

Table 43. Summary of corridor-clearing disturbance intensities along Hells Canyon Complex transmission-line service roads.

Km Km with Km with Km with Km with Km with Line Surveyed No Slight Moderate High Extreme Number per Line Disturbance Disturbance Disturbance Disturbance Disturbance 903 66.7 66.7 0.0 0.0 0.0 0.0 904 78.0 78.0 0.0 0.0 0.0 0.0 905 27.0 27.0 0.0 0.0 0.0 0.0 906 58.9 58.9 0.0 0.0 0.0 0.0 907 30.3 20.3 1.7 3.0 5.2 0.0 908 10.5 9.9 0.0 0.6 0.0 0.0 910 8.6 6.2 0.5 0.0 1.9 0.0 911 76.2 76.2 0.0 0.1 0.0 0.0 912 77.1 77.1 0.0 0.0 0.0 0.0 913 16.6 7.3 0.0 2.1 7.2 0.0 951 18.0 18.0 0.0 0.0 0.0 0.0

Total 467.8 445.6 2.2 5.7 14.3 0.0

Table 44. Summary of fire disturbance intensities along Hells Canyon Complex transmission-line service roads.

Km Km with Km with Km with Km with Km with Line Surveyed No Slight Moderate High Extreme Number per Line Disturbance Disturbance Disturbance Disturbance Disturbance 903 66.7 55.1 8.1 3.4 0.0 0.0 904 78.0 47.7 5.4 10.7 12.1 2.3 905 27.0 26.0 0.7 0.4 0.0 0.0 906 58.9 13.4 10.4 20.7 9.9 4.5 907 30.3 27.1 2.2 1.0 0.0 0.0 908 10.5 10.5 0.0 0.0 0.0 0.0 910 8.6 8.6 0.0 0.0 0.0 0.0 911 76.2 33.6 14.7 15.9 10.1 2.0 912 77.1 18.3 13.8 18.9 13.8 12.4 913 16.6 10.6 5.9 0.0 0.0 0.0 951 18.0 4.7 1.7 5.5 5.1 1.0

Total 467.8 255.5 62.9 76.4 51.0 22.0

Page 146 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line

Table 45. Summary of industrial disturbance intensities along Hells Canyon Complex transmission-line service roads.

Km Km with Km with Km with Km with Km with Line Surveyed No Slight Moderate High Extreme Number per Line Disturbance Disturbance Disturbance Disturbance. Disturbance 903 66.7 66.7 0.0 0.0 0.0 0.0 904 78.0 75.2 0.6 0.6 0.0 1.7 905 27.0 27.0 0.0 0.0 0.0 0.0 906 58.9 58.9 0.0 0.0 0.0 0.0 907 30.3 29.3 0.4 0.5 0.0 0.0 908 10.5 10.5 0.0 0.0 0.0 0.0 910 8.6 8.6 0.0 0.0 0.0 0.0 911 76.2 76.2 0.0 0.0 0.0 0.0 912 77.1 77.1 0.0 0.0 0.0 0.0 913 16.6 15.1 1.5 0.0 0.0 0.0 951 18.0 18.0 0.0 0.0 0.0 0.0

Total 467.8 462.5 2.5 1.1 0.0 1.7

Table 46. Summary of livestock grazing disturbance intensities along Hells Canyon Complex transmission-line service roads.

Km Km with Km with Km with Km with Km with Line Surveyed No Slight Moderate High Extreme Number per Line Disturbance. Disturbance Disturbance Disturbance. Disturbance 903 66.7 0.3 17.2 27.5 13.0 8.6 904 78.0 1.9 30.5 23.7 15.2 6.8 905 27.0 2.1 4.6 8.7 10.1 1.4 906 58.9 0.9 6.6 39.0 12.4 0.0 907 30.3 21.0 1.4 3.2 4.7 0.0 908 10.5 0.5 0.6 2.4 1.4 5.6 910 8.6 5.9 2.6 0.0 0.0 0.0 911 76.2 5.9 25.1 30.8 13.6 0.8 912 77.1 4.8 16.6 31.4 15.4 8.8 913 16.6 2.1 7.4 2.9 4.1 0.0 951 18.0 0.0 5.7 8.9 1.7 1.7

Total 467.8 45.5 118.3 178.6 91.6 33.8

Hells Canyon Complex Page 147 Effects of Road and Transmission Line Idaho Power Company

Table 47. Summary of logging disturbance intensities along Hells Canyon Complex transmission-line service roads.

Km Km with Km with Km with Km with Km with Line Surveyed No Slight Moderate High Extreme Number per Line Disturbance Disturbance Disturbance Disturbance Disturbance 903 66.7 66.7 0.0 0.0 0.0 0.0 904 78.0 78.0 0.0 0.0 0.0 0.0 905 27.0 27.0 0.0 0.0 0.0 0.0 906 58.9 58.9 0.0 0.0 0.0 0.0 907 30.3 27.3 2.2 0.7 0.0 0.0 908 10.5 10.5 0.0 0.0 0.0 0.0 910 8.6 6.0 0.0 2.5 0.0 0.0 911 76.2 76.2 0.0 0.0 0.0 0.0 912 77.1 77.1 0.0 0.0 0.0 0.0 913 16.6 7.3 3.3 4.9 1.1 0.0 951 18.0 18.0 0.0 0.0 0.0 0.0

Total 467.8 452.9 5.6 8.2 1.1 0.0

Table 48. Summary of non-project road disturbance intensities along Hells Canyon Complex transmission-line service roads.

Km Km with Km with Km with Km with Km with Line Surveyed No Slight Moderate High Extreme Number per Line Disturbance Disturbance Disturbance Disturbance. Disturbance 903 66.67 36.39 24.62 5.35 0.30 0.00 904 78.04 49.35 22.16 3.60 2.66 0.26 905 27.01 24.75 0.70 1.56 0.00 0.00 906 58.86 18.03 33.11 6.70 1.02 0.00 907 30.29 18.87 3.59 4.73 2.91 0.19 908 10.45 7.22 1.06 2.17 0.00 0.00 910 8.55 3.95 2.75 1.41 0.44 0.00 911 76.25 43.50 22.47 6.99 3.30 0.00 912 77.06 38.45 34.61 0.77 1.71 1.52 913 16.57 5.43 4.43 3.69 2.49 0.52 951 18.02 4.01 14.01 0.00 0.00 0.00

Total 467.76 249.95 163.50 36.98 14.83 2.50

Page 148 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line

Table 49. Summary of off-highway vehicle disturbance intensities along Hells Canyon Complex transmission-line service roads.

Km Km with Km with Km with Km with Km with Line Surveyed No Slight Moderate High Extreme Number per Line Disturbance Disturbance Disturbance Disturbance. Disturbance 903 66.67 43.85 21.54 1.17 0.11 0.00 904 78.04 44.00 26.90 7.13 0.00 0.00 905 27.01 23.86 2.54 0.61 0.00 0.00 906 58.86 12.85 37.93 8.08 0.00 0.00 907 30.29 25.78 4.16 0.36 0.00 0.00 908 10.45 9.08 0.00 1.37 0.00 0.00 910 8.55 6.94 1.62 0.00 0.00 0.00 911 76.25 41.46 27.52 7.27 0.00 0.00 912 77.06 12.25 60.21 3.66 0.95 0.00 913 16.57 16.17 0.40 0.00 0.00 0.00 951 18.02 2.51 15.51 0.00 0.00 0.00

Total 467.76 238.74 198.33 29.64 1.06 0.00

Table 50. Summary of residential disturbance intensities along Hells Canyon Complex transmission-line service roads.

Km Km with Km with Km with Km with Km with Line Surveyed No Slight Moderate High Extreme Number per Line Disturbance Disturbance Disturbance Disturbance. Disturbance 903 66.67 66.67 0.00 0.00 0.00 0.00 904 78.04 78.04 0.00 0.00 0.00 0.00 905 27.01 27.01 0.00 0.00 0.00 0.00 906 58.86 58.86 0.00 0.00 0.00 0.00 907 30.29 29.11 0.87 0.31 0.00 0.00 908 10.45 10.45 0.00 0.00 0.00 0.00 910 8.55 8.55 0.00 0.00 0.00 0.00 911 76.25 76.25 0.00 0.00 0.00 0.00 912 77.06 77.06 0.00 0.00 0.00 0.00 913 16.57 16.57 0.00 0.00 0.00 0.00 951 18.02 18.02 0.00 0.00 0.00 0.00

Total 467.76 466.58 0.87 0.31 0.00 0.00

Hells Canyon Complex Page 149 Effects of Road and Transmission Line Idaho Power Company

Table 51. Summary of road use intensities along Hells Canyon Complex transmission- line service roads.

Km Km with Km with Km with Km with Km with Line Surveyed No Slight Moderate High Extreme Number per Line Disturbance Disturbance Disturbance. Disturbance. Disturbance. 903 66.7 10.4 15.6 33.8 6.9 0.0 904 78.1 0.0 17.9 57.8 2.4 0.0 905 27.0 0.0 27.0 0.0 0.0 0.0 906 58.8 0.0 26.7 30.2 1.9 0.0 907 30.3 1.9 9.5 16.2 2.7 0.0 908 10.5 0.0 0.5 8.6 1.4 0.0 910 8.5 0.0 2.3 6.2 0.0 0.0 911 76.2 0.0 22.0 50.1 4.1 0.0 912 77.0 0.0 10.9 58.8 7.3 0.0 913 16.5 0.0 5.9 10.6 0.0 0.0 951 18.0 0.0 5.7 10.6 1.7 0.0

Total 467.6 12.3 144.0 282.9 28.4 0.0

Table 52. Summary of service road disturbance intensities along Hells Canyon Complex transmission-line service roads.

Km Km with Km with Km with Km with Km with Line Surveyed No Slight Moderate High Extreme Number per Line Disturbance Disturbance Disturbance Disturbance. Disturbance 903 66.67 3.58 18.39 42.72 1.98 0.00 904 78.04 0.00 12.81 48.71 15.82 0.70 905 27.01 0.00 0.02 14.11 11.77 1.11 906 58.86 0.00 17.48 41.37 0.00 0.00 907 30.29 0.39 2.42 19.62 7.86 0.00 908 10.45 0.00 0.44 9.46 0.55 0.00 910 8.55 0.00 0.12 2.33 6.09 0.00 911 76.25 1.70 5.95 63.11 5.48 0.00 912 77.06 0.00 13.47 60.94 2.65 0.00 913 16.57 0.00 5.08 6.76 3.25 1.48 951 18.02 0.00 5.68 12.34 0.00 0.00

Total 467.76 5.68 81.86 321.48 55.46 3.29

Page 150 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line

Table 53. Summary of water erosion disturbance intensities along Hells Canyon Complex transmission-line service roads.

Km Km with Km with Km with Km with Km with Line Surveyed No Slight Moderate High Extreme Number per Line Disturbance Disturbance Disturbance Disturbance Disturbance 903 66.67 30.63 15.29 18.04 2.70 0.00 904 78.04 31.04 14.98 16.76 11.62 3.64 905 27.01 15.59 2.87 5.85 2.30 0.40 906 58.86 37.22 21.63 0.00 0.00 0.00 907 30.29 14.31 6.03 7.26 1.01 1.69 908 10.45 2.07 2.81 5.02 0.00 0.55 910 8.55 6.05 1.74 0.76 0.00 0.00 911 76.25 19.89 15.42 28.79 12.15 0.00 912 77.06 40.48 20.88 10.89 4.82 0.00 913 16.57 11.60 2.06 0.92 2.00 0.00 951 18.02 15.92 2.10 0.00 0.00 0.00

Total 467.76 224.80 105.80 94.29 36.60 6.28

Table 54. Summary of disturbance types and intensities on Hells Canyon Complex transmission-line survey units (%) on Line 903.

Units with Units with Units with Units with Units with No Slight Moderate High Extreme Disturbance Type: Disturbance Disturbance Disturbance Disturbance Disturbance Agriculture 100 0 0 0 0 Big game 26 41 33 0 0 Corridor clearing 100 0 0 0 0 Fire 83 12 5 0 0 Industrial 100 0 0 0 0 Livestock 0 26 41 20 13 Logging 100 0 0 0 0 Non-project roads 66 32 2 0 0 Off-highway vehicles 55 37 8 0 0 Residential 100 0 0 0 0 Road use 21 25 44 10 0 Service roads 5 28 64 3 0 Water erosion 46 23 27 4 0

Hells Canyon Complex Page 151 Effects of Road and Transmission Line Idaho Power Company

Table 55. Summary of disturbance types and intensities on Hells Canyon Complex transmission-line survey units (%) on Line 904.

Units with Units with Units with Units with Units with No Slight Moderate High Extreme Disturbance Type: Disturbance Disturbance Disturbance Disturbance Disturbance Agriculture 99 1 0 0 0 Big game 32 46 18 1 2 Corridor clearing 100 0 0 0 0 Fire 61 7 14 15 3 Industrial 96 1 1 0 2 Livestock 2 39 30 19 9 Logging 100 0 0 0 0 Non-project roads 56 34 9 0 0 Off-highway vehicles 63 28 5 3 0 Residential 100 0 0 0 0 Road use 0 28 69 3 0 Service roads 0 16 62 20 1 Water erosion 40 19 21 15 5

Table 56. Summary of disturbance types and intensities on Hells Canyon Complex transmission-line survey units (%) on Line 905.

Units with Units with Units with Units with Units with No Slight Moderate High Extreme Disturbance Type: Disturbance Disturbance Disturbance Disturbance Disturbance Agriculture 100 0 0 0 0 Big game 23 20 31 26 0 Corridor clearing 100 0 0 0 0 Fire 96 3 1 0 0 Industrial 100 0 0 0 0 Livestock 8 17 32 37 5 Logging 100 0 0 0 0 Non-project roads 88 9 2 0 0 Off-highway vehicles 92 3 6 0 0 Residential 100 0 0 0 0 Road use 0 100 0 0 0 Service roads 0 0 52 44 4 Water erosion 58 11 22 9 1

Page 152 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line

Table 57. Summary of disturbance types and intensities on Hells Canyon Complex transmission-line survey units (%) on Line 906.

Units with Units with Units with Units with Units with No Slight Moderate High Extreme Disturbance Type: Disturbance Disturbance Disturbance Disturbance Disturbance

Agriculture 89 9 2 0 0 Big game 31 41 28 0 0 Corridor clearing 100 0 0 0 0 Fire 23 18 35 17 8 Industrial 100 0 0 0 0 Livestock 1 11 66 21 0 Logging 100 0 0 0 0 Non-project roads 22 64 14 0 0 Off-highway vehicles 31 56 11 2 0 Residential 100 0 0 0 0 Road use 0 49 46 5 0 Service roads 0 30 70 0 0 Water erosion 63 37 0 0 0

Table 58. Summary of disturbance types and intensities on Hells Canyon Complex transmission-line survey units (%) on Line 907.

Units with Units with Units with Units with Units with No Slight Moderate High Extreme Disturbance Type: Disturbance Disturbance Disturbance Disturbance Disturbance

Agriculture 98 2 0 0 0 Big game 42 35 20 4 0 Corridor clearing 67 6 10 17 0 Fire 89 7 3 0 0 Industrial 97 1 2 0 0 Livestock 69 4 11 15 0 Logging 90 7 2 0 0 Non-project roads 85 14 1 0 0 Off-highway vehicles 62 12 16 10 1 Residential 96 3 1 0 0 Road use 8 26 56 10 0 Service roads 1 8 65 26 0 Water erosion 47 20 24 3 6

Hells Canyon Complex Page 153 Effects of Road and Transmission Line Idaho Power Company

Table 59. Summary of disturbance types and intensities on Hells Canyon Complex transmission-line survey units (%) on Line 908.

Units with Units with Units with Units with Units with No Slight Moderate High Extreme Disturbance Type: Disturbance Disturbance Disturbance Disturbance Disturbance

Agriculture 100 0 0 0 0 Big game 80 20 0 0 0 Corridor clearing 95 0 5 0 0 Fire 100 0 0 0 0 Industrial 100 0 0 0 0 Livestock 5 5 23 13 54 Logging 100 0 0 0 0 Non-project roads 87 0 13 0 0 Off-highway vehicles 69 10 21 0 0 Residential 100 0 0 0 0 Road use 5 84 11 0 0 Service roads 0 4 90 5 0 Water erosion 20 27 48 0 5

Table 60. Summary of disturbance types and intensities on Hells Canyon Complex transmission-line survey units (%) on Line 910.

Units with Units with Units with Units with Units with No Slight Moderate High Extreme Disturbance Type: Disturbance Disturbance Disturbance Disturbance Disturbance

Agriculture 100 0 0 0 0 Big game 45 55 0 0 0 Corridor clearing 73 6 22 0 0 Fire 100 0 0 0 0 Industrial 100 0 0 0 0 Livestock 69 31 0 0 0 Logging 100 0 0 0 0 Non-project roads 81 19 0 0 0 Off-highway vehicles 46 32 17 5 0 Residential 100 0 0 0 0 Road use 0 31 69 0 0 Service roads 0 1 27 71 0 Water erosion 71 20 9 0 0

Page 154 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line

Table 61. Summary of disturbance types and intensities on Hells Canyon Complex transmission-line survey units (%) on Line 911.

Units with Units with Units with Units with Units with No Slight Moderate High Extreme Disturbance Type: Disturbance Disturbance Disturbance Disturbance Disturbance

Agriculture 95 5 0 0 0 Big game 11 42 44 3 0 Corridor clearing 100 0 0 0 0 Fire 44 19 21 13 3 Industrial 100 0 0 0 0 Livestock 8 33 40 18 1 Logging 100 0 0 0 0 Non-project roads 54 36 10 0 0 Off-highway vehicles 57 29 9 4 0 Residential 100 0 0 0 0 Road use 0 37 57 6 0 Service roads 2 8 83 7 0 Water erosion 26 20 38 16 0

Table 62. Summary of disturbance types and intensities on Hells Canyon Complex transmission-line survey units (%) on Line 912.

Units with Units with Units with Units with Units with No Slight Moderate High Extreme Disturbance Type: Disturbance Disturbance Disturbance Disturbance Disturbance

Agriculture 100 0 0 0 0 Big game 22 38 35 5 0 Corridor clearing 100 0 0 0 0 Fire 24 18 24 18 16 Industrial 100 0 0 0 0 Livestock 6 22 41 20 11 Logging 100 0 0 0 0 Non-project roads 16 78 5 1 0 Off-highway vehicles 50 45 1 2 2 Residential 100 0 0 0 0 Road use 0 18 73 9 0 Service roads 0 17 79 3 0 Water erosion 53 27 14 6 0

Hells Canyon Complex Page 155 Effects of Road and Transmission Line Idaho Power Company

Table 63. Summary of disturbance types and intensities on Hells Canyon Complex transmission-line survey units (%) on Line 913.

Units with Units with Units with Units with Units with No Slight Moderate High Extreme Disturbance Type: Disturbance Disturbance Disturbance Disturbance Disturbance

Agriculture 100 0 0 0 0 Big game 70 23 6 0 0 Corridor clearing 44 0 13 43 0 Fire 64 36 0 0 0 Industrial 91 9 0 0 0 Livestock 13 45 18 25 0 Logging 100 0 0 0 0 Non-project roads 98 2 0 0 0 Off-highway vehicles 33 27 22 15 3 Residential 100 0 0 0 0 Road use 0 35 65 0 0 Service roads 0 31 41 20 9 Water erosion 70 12 6 12 0

Table 64. Summary of disturbance types and intensities on Hells Canyon Complex transmission-line survey units (%) on Line 951.

Units with Units with Units with Units with Units with No Slight Moderate High Extreme Disturbance Type: Disturbance Disturbance Disturbance Disturbance Disturbance Agriculture 100 0 0 0 0 Big game 38 62 0 0 0 Corridor clearing 100 0 0 0 0 Fire 26 9 31 29 5 Industrial 100 0 0 0 0 Livestock 0 32 50 9 9 Logging 100 0 0 0 0 Non-project roads 14 86 0 0 0 Off-highway vehicles 22 78 0 0 0 Residential 100 0 0 0 0 Road use 0 27 64 9 0 Service roads 0 32 68 0 0 Water erosion 88 12 0 0 0

Page 156 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line

Table 65. Hells Canyon Complex transmission-line maintenance activities on a line- by-line basis.

Last Year Seasonal No. No. Incidence Next Treatment Techniquea Done Windowb Days Crews Crew Type per 10 yrsc Activity Equipmentd

Line 903 Corridor Clearing C, R 1999 5–11 2 3 3-man 2009 PU, ATV Emergency PU, LB, BT, CR, Maintenance 6 CAT, BK Inspection Climbing 1997 1–12 30 1 4-man 2005 PU, ATV Line 3–5, PU, LB, BT, CR, Maintenance Routine 2000 9–11 4 1 6-man 2001 CAT, BK Patrol Air 2000 3–5 1 1 2-man 2001 HEL Patrol Ground 2000 6–10 5 1 patrolman 2001 PU, ATV Pole Inspection 1996 1–12 20 1 6-man 2005 PU, ATV Pole 3–5, PU, LB, BT, CR, Replacement 1998 9–11 32 1 6-man 2007 CAT, BK Line 904 Cathodic Protection Surv Ground 2000 1–12 15 1 patrolman 2005 PU, ATV Corridor Clearing C, R, T 1999 4-11 2 3 3-man 2009 PU, ATV Emergency PU, CD, CR, Maintenance 4 CAT, HL, RT, BK Hazard Trees 1997 5–11 0.5 1 3-man 2000 PU, ATV 12–2, Inspection Air 1999 6–8 10 1 2-man 2009 HEL Inspection 3, 4, 10, PU, CD, CR, Maintenance 2000 11 15 1 6-man 2010 CAT, HL, RT, BK Line 3, 4, 10, PU, CD, CR, Maintenance Routine 2000 11 3 1 6-man 2001 CAT, HL, RT, BK Patrol Air 2000 3–5 1 1 2-man 2001 HEL Patrol Ground 2000 6–10 15 1 patrolman 2001 PU, ATV Line 905 Cathodic Protection Surv Ground 2001 1–12 1 1 patrolman 2006 PU, ATV Corridor Clearing C, R 1999 2 3 3-man PU, ATV Emergency PU, CD, CR, Maintenance 1 CAT, HL, RT, BK Inspection Air 2000 6–8 1 1 2-man 2110 HEL Inspection 1–4, PU, CD, CR, Maintenance 2001 10–12 5 1 6-man 2011 CAT, HL, RT, BK Line 1–4, PU, CD, CR, Maintenance Routine 2000 10–12 3 1 6-man 2001 CAT, HL, RT, BK 1–2, Patrol Ground 2000 6–12 1 1 patrolman 2001 PU, ATV Patrol Air 2000 3–5 1 1 2-man 2001 HEL

a Technique: C = chemical, R = removal, T = trim. b Season depicted numerically by month of the year (e.g., 1 = January, 2 = February, etc.). c "Per 10 year" estimates the number of emergency maintenance events that will occur over the next 10 years. d Equipment: ATV = all-terrain behicle, BK = backhoe, BT = bucket truck, CAT = caterpillar, CD = condor, CR = crane, HEL = helicopter, HL = hardline truck, LB = linebed truck, PU = pickup, RT = rope truck.

Hells Canyon Complex Page 157 Effects of Road and Transmission Line Idaho Power Company

Table 65. (Cont.)

Last Year Seasonal No. No. Incidence Next Treatment Techniquea Done Windowb Days Crews Crew Type per 10 yrsc Activity Equipmentd

Line 906 Emergency Maintenance 3 Inspection Air 1991 HEL Inspection Climbing 4–10 60 1 4-man 2002 PU, ATV Inspection Maintenance 1995 0 0 Line PU, LB, BT, CR, Maintenance Routine 2000 1–12 7 1 6-man 2001 CAT, BK Patrol Ground 2000 4–10 13 2 patrolmen 2001 PU, ATV Pole Inspection 1991 1–12 30 1 6-man 2002 PU, ATV Pole PU, LB, BT, CR, Replacement 1995 1–12 68 1 6-man 2003 CAT, BK Line 907 Cathodic Protection Surv Ground 2001 6–11 3 1 patrolman 2006 PU, ATV Corridor Clearing C, R 2000 5–11 12 4 3-man 0 2009 PU, ATV Hazard Trees T 1999 5–11 3 3 3-man 2009 PU, ATV Emergency PU, CD, CR, Maintenance 3 CAT, HL, RT, BK 12–2, Inspection Air 2000 6–8 1 1 2-man 2010 HEL Inspection 3–5, PU, CD, CR, Maintenance 2001 9–11 5 1 6-man 2011 CAT, HL, RT, BK Line 3–5, PU, CD, CR, Maintenance Routine 2000 9–11 2 1 6-man 2001 CAT, HL, RT, BK Patrol Air 2000 3–5 1 1 2-man 2001 HEL Patrol Ground 2000 6–11 5 1 patrolman 2001 PU, ATV Line 908 Corridor Clearing C, R 1999 5–11 18 3 3-man 2009 PU, ATV Emergency Maintenance 4 Hazard Tree 1997 5–11 3 3 3-man 2003 PU, ATV 12–2, Inspection Climbing 1998 6–8 15 1 4-man 2007 PU, ATV Line 3–5, PU, LB, BT, CR, Maintenance Routine 2000 9–11 3 1 6-man 2001 CAT, BK Patrol Ground 2000 6–11 4 1 patrolman 2001 PU, ATV Patrol Air 2000 3–5 1 1 2-man 2001 HEL Pole Inspection 1997 3–11 20 1 6-man 2007 PU, ATV Pole 3–5, PU, LB, BT, CR, Replacement 1999 9–11 16 1 6-man 2008 CAT, BK

a Technique: C = chemical, R = removal, T = trim. b Season depicted numerically by month of the year (e.g., 1 = January, 2 = February, etc.). c "Per 10 year" estimates the number of emergency maintenance events that will occur over the next 10 years. d Equipment: ATV = all-terrain behicle, BK = backhoe, BT = bucket truck, CAT = caterpillar, CD = condor, CR = crane, HEL = helicopter, HL = hardline truck, LB = linebed truck, PU = pickup, RT = rope truck.

Page 158 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line

Table 65. (Cont.)

Last Year Seasonal No. No. Incidence Next Treatment Techniquea Done Windowb Days Crews Crew Type per 10 yrsc Activity Equipmentd

Line 910 Corridor Clearing T, R 2001 6–10 13 3 3-man 2010 PU, ATV Emergency PU, CD, CR, Maintenance 1 CAT, HL, RT, BK Hazard Trees 1999 6–10 1 2 3-man 2001 PU, ATV 12–2, Inspection Air 2000 6–8 11 1 2-man 2010 HEL Inspection 3–5, PU, CD, CR, Maintenance 2001 9–11 5 1 6-man 2011 CAT, HL, RT, BK Line 3–5, PU, CD, CR, Maintenance Routine 2000 9–11 2 1 6-man 2001 CAT, HL, RT, BK Patrol Air 2000 3–5 1 1 2-man 2001 HEL Patrol Ground 2000 6–11 2 1 patrolman 2001 PU, ATV Line 911 Cathodic Protection Surv Ground 2002 3–11 15 1 patrolman 2007 PU, ATV Corridor Clearing C, T, R 1999 4–11 2 3 3-man 2009 PU, ATV Emergency PU, CD, CR, Maintenance 4 CAT, HL, RT, BK 12–2, Inspection Air 2000 6–8 11 1 2-man 2010 HEL Inspection 3, 4, 10, PU, CD, CR, Maintenance 2001 11 16 1 6-man 2011 CAT, HL, RT, BK Line 3, 4, 10, PU, CD, CR, Maintenance Routine 2000 11 2 1 6-man 2001 CAT, HL, RT, BK Patrol Ground 2000 6-11 15 1 patrolman 2001 PU, ATV Patrol Air 2000 3-5 1 1 2-man 2001 HEL Line 912 Corridor Clearing C, R 1999 5–11 0.5 1 3-man 2004 PU, ATV Emergency PU, CD, CR, Maintenance 3 CAT, HL, RT, BK Inspection Climbing 1996 3–11 30 1 4-man 2006 PU, ATV Line PU, CD, CR, Maintenance Routine 2000 1–12 3 1 6-man 2001 CAT, HL, RT, BK Patrol Ground 2000 3–11 14 1 patrolman 2001 PU, ATV Pole Inspection 1995 3–11 20 1 6-man 2006 PU, ATV Pole PU, CD, CR, Replacement 1997 1–12 25 1 6-man 2007 CAT, HL, RT, BK

a Technique: C = chemical, R = removal, T = trim. b Season depicted numerically by month of the year (e.g., 1 = January, 2 = February, etc.). c "Per 10 year" estimates the number of emergency maintenance events that will occur over the next 10 years. d Equipment: ATV = all-terrain behicle, BK = backhoe, BT = bucket truck, CAT = caterpillar, CD = condor, CR = crane, HEL = helicopter, HL = hardline truck, LB = linebed truck, PU = pickup, RT = rope truck.

Hells Canyon Complex Page 159 Effects of Road and Transmission Line Idaho Power Company

Table 65. (Cont.)

Last Year Seasonal No. No. Incidence Next Treatment Techniquea Done Windowb Days Crews Crew Type per 10 yrsc Activity Equipmentd

Line 913 Corridor Clearing 1997 5-11 17 3 3-man 2007 PU, ATV Emergency PU, CD, CR, Maintenance 2 CAT, HL, RT, BK Hazard Trees 1999 5–11 1 2 3-man 2004 PU, ATV Inspection Climbing 1998 3–11 20 1 4-man 2007 PU, ATV Line 3–5, PU, CD, CR, Maintenance Routine 2000 9–11 3 1 6-man 2001 CAT, HL, RT, BK Patrol Ground 2000 6-11 6 1 patrolman 2001 PU, ATV Patrol Air 2000 3-5 1 1 2-man 2001 HEL Pole Inspection 1997 3–11 20 1 6-man 2007 PU, ATV Pole 3–5, PU, CD, CR, Replacement 2000 9–11 18 1 6-man 2008 CAT, HL, RT, BK Line 923 Emergency PU, LB, BT, CR, Maintenance 3 CAT, BK Inspection Climbing 2000 3–11 4 1 4-man 2009 PU, ATV Line 3–5, PU, LB, BT, CR, Maintenance Routine 2000 9–11 1 1 6-man 2001 CAT, BK Patrol Ground 2000 3–11 1 1 patrolman 2001 PU, ATV Pole Inspection 1999 3–11 3 1 6-man 2009 PU, ATV Pole 3–5, PU, LB, BT, CR, Replacement 2000 9–11 2 1 6-man 2010 CAT, BK Line 945 Corridor Clearing 1998 5–11 3 1 3-man 2003 PU, ATV Emergency PU, LB, BT, CR, Maintenance 4 CAT, BK Line PU, LB, BT, CR, Maintenance Routine 2000 1–12 3 1 5-man 2001 CAT, BK Patrol Ground 2000 6-11 1 1 patrolman 2001 PU, ATV Patrol Air 2000 3-5 1 1 2-man 2001 HEL Pole Inspection 1999 1–12 20 1 6-man 2009 PU, ATV Pole PU, LB, BT, CR, Replacement 1999 1–12 15 1 6-man 2010 CAT, BK

a Technique: C = chemical, R = removal, T = trim. b Season depicted numerically by month of the year (e.g., 1 = January, 2 = February, etc.). c "Per 10 year" estimates the number of emergency maintenance events that will occur over the next 10 years. d Equipment: ATV = all-terrain behicle, BK = backhoe, BT = bucket truck, CAT = caterpillar, CD = condor, CR = crane, HEL = helicopter, HL = hardline truck, LB = linebed truck, PU = pickup, RT = rope truck.

Page 160 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line

Table 65. (Cont.)

Last Year Seasonal No. No. Incidence Next Treatment Techniquea Done Windowb Days Crews Crew Type per 10 yrsc Activity Equipmentd

Line 951 Emergency PU, LB, BT, CR, Maintenance 5 CAT, BK 1–5, Inspection Air 1990 9–12 8 1 2-man 2001 HEL Line PU, LB, BT, CR, Maintenance Routine 2000 5–8 3 1 6-man 2001 CAT, BK Patrol Ground 2000 3–11 8 1 patrolman 2001 PU, ATV Pole Inspection 1989 3–11 45 1 6-man 2000 PU, ATV Pole PU, LB, BT, CR, Replacement 1991 5–8 50 1 6-man 2001 CAT, BK Line 952 Emergency PU, CD, CR, Maintenance 1 CAT, HL, RT, BK 1–5, Inspection Air 2001 9–12 1 1 2-man 2011 HEL Inspection PU, CD, CR, Maintenance 2002 5–8 3 1 6-man 2012 CAT, HL, RT, BK Line PU, CD, CR, Maintenance Routine 2000 5–8 1 1 6-man 2001 CAT, HL, RT, BK Patrol Ground 2000 3–11 1 1 patrolman 2001 PU, ATV

a Technique: C = chemical, R = removal, T = trim. b Season depicted numerically by month of the year (e.g., 1 = January, 2 = February, etc.). c "Per 10 year" estimates the number of emergency maintenance events that will occur over the next 10 years. d Equipment: ATV = all-terrain behicle, BK = backhoe, BT = bucket truck, CAT = caterpillar, CD = condor, CR = crane, HEL = helicopter, HL = hardline truck, LB = linebed truck, PU = pickup, RT = rope truck.

Table 66. Regional summary of hectares and number of vegetation patches intersecting Hells Canyon Complex transmission line rights-of-way (ROW) and comparison areas (1 km out from either side of the ROW). The Idaho Canyon/Mountain region has only an east side.

Hectares Number of Patches North or South or North or South or Region East Side ROW West Side East Side ROW West Side Snake River Plain 1,778,006 1,774,604 1,776,222 355 383 398 Snake River Plateau 920,269 917,196 920,302 629 606 621 Payette 132,290 135,249 159,412 1,145 1,191 1,115 Idaho Canyon/ Mountain 330,996 61,102 412 280 Wallowa Whitman Forest 57,348 55,914 97,945 102 131 91

Hells Canyon Complex Page 161 Effects of Road and Transmission Line Idaho Power Company

Table 67. Snake River Plain region composition of cover types intersecting the transmission line rights-of-way (ROW) and comparison areas (1 km out from either side of the ROW). Cover types present but contributing less than 0.1% to dominance are shown as 0.

Dominance (%) Number of patches Mean patch size (ha) Patch size std dev (ha)

North South North South North South North South Cover type Side ROW Side Side ROW Side Side ROW Side Side ROW Side

Agricultural 48.2 48.3 48.4 6 8 9 142,860 107,171 95,584 201,623 185,229 177,684

Sagebrush 46.8 46.9 46.9 117 107 103 7,117 7,785 8,092 76,403 79,861 81,381

Perennial grass 4.1 4.2 4.1 128 138 150 575 536 485 4,950 4,769 4,577

Water 0.6 0.4 0.4 1 4 5 11,258 1,746 1,408 2,9892,758

Rabbitbrush 0.1 0.1 0.1 14 25 32 126 71 55 418 319 283

High density urban 0 0 1 1 696 696

Annual grassland 0 0 0 21 30 28 8 12 14 14 33 34

Low sagebrush 0 0 0 54 53 48 8 4 7 14 5 12

Highly disturbed land 0 0 1 1 107 107

Lava 0 0 0 8 7 7 19 14 22 44 22 27

Riparian 0 0 4 11 8 10 12 13

Low disturbed land 0 2 14 10

Barren 0 1 2

Dry meadow 0 0 0 4 1 1 2 1 1 1

Wet meadow 0 0 1 2 1 10 4

Wetland 0 1 1

Bitterbrush 0 1 1

Page 162 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line

Table 68. Snake River Plateau Region composition of cover types intersecting the transmission line rights-of-way (ROW) and comparison areas (1 km out from either side of the ROW). Cover types present but contributing less than 0.1% to dominance are shown as 0.

Dominance (%) Number of patches Mean patch size (ha) Patch size std dev (ha)

North South North South North South North South Cover Type Side ROW Side Side ROW Side Side ROW Side Side ROW Side Sagebrush 93.9 94.3 94.0 189 157 148 4,572 5,508 5,848 60,214 66,027 67,990

Burned herbaceous 2.0 1.9 1.9 13 4 1 1,384 4,441 17,729 4,719 7,672 0

Perennial grass 1.9 1.8 2.1 213 244 260 80 68 73 327 305 303

Agricultural 0.7 1.3 1.3 9 12 13 736 1,002 920 952 1,219 1,203

Rabbitbrush 0.4 0.4 0.4 39 62 84 90 63 41 379 305 242

Annual grassland 0.2 0.2 0.2 38 57 55 40 28 41 90 68 92

Water 0.1 0 4 1 265 1 396

Salt desert shrub 0 0 0 40 36 28 7 8 6 9 11 6

Low sagebrush 0 0 0 22 13 20 9 8 9 11 14 16

Bitterbrush 0.8 0 38 7 203 15 612 16

Riparian 0 0 0 14 12 10 18 7 5 18 8 5

Dry meadow 0 1 3

Burned shrub 0 0 5 1 3 2 2

Dry forest 0 2 3 2

Montane shrub 0 1 2

Mountain Big sage 0 2 1

Wet meadow 0 1 3

Hells Canyon Complex Page 163 Effects of Road and Transmission Line Idaho Power Company

Table 69. Payette Region composition of cover types intersecting the transmission line rights-of-way (ROW) and comparison areas (1 km out from either side of the ROW). Cover types present but contributing less than 0.1% to dominance are shown as 0.

Dominance (%) Number of patches Mean patch size (ha) Patch size std dev (ha)

Cover Type East Side ROW West Side East Side ROW West Side East Side ROW West Side East Side ROW West Side

Perennial grass 28.4 31.6 25.7 260 276 261 145 155 157 671 710 718 High density urban 30.8 30.1 25.5 1 1 1 40,726 40,726 40,726 Sagebrush 17.8 17.2 18.0 158 185 162 149 126 177 883 817 925 Bitterbrush 12.2 12.3 9.8 264 273 254 61 61 62 232 225 232 Agricultural 6.6 4.9 5.6 10 11 19 874 605 472 1,309 844 702 Annual grassland 1.0 1.1 1.5 71 104 119 19 15 21 60 48 54 Low sagebrush 1.4 1.1 1.0 159 152 126 12 10 13 34 25 43 Montane shrub 0.6 0.6 0.4 70 57 56 12 14 10 24 26 25 Riparian 0.5 0.4 0.4 63 59 56 10 9 10 17 16 17 Water 0.3 0.3 0.3 8 4 4 46 105 105 111 136 136 Mountain Big sage 0.3 0.1 0.2 59 43 22 6 4 13 12 6 37 Dry forest 0 0.1 11.5 8 11 19 7 10 966 9 19 4,060 Salt desert shrub 0 0 0 7 4 4 3 4 6 4 2 5 Rabbitbrush 0 0 4 2 3 2 2 1 Dry meadow 0 0 0 3 4 5 2 2 2 1 1 Low density urban 0 0 0 1 1 2 6 6 10 10 Perennial grass montane 0 0 0 1 2 1 1 1 13 1 Highly disturbed land 0 0.1 1 2 4 44 32 Wetland 0 1 2

Page 164 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line

Table 70. Idaho Canyon/Mountain region composition of cover types intersecting the transmission line rights-of-way (ROW) and comparison areas (1 km to the east of the ROW). Cover types present but contributing less than 0.1% to dominance are shown as 0.

Number of Mean Patch Patch Size Standard Dominance (%) Patches Size (ha) Deviation (ha)

Cover Type ROW East ROW East ROW East ROW East Dry forest 73.4 95.8 27 61 1,661 5,200 5,486 36,836 Perennial grass 21.4 3.1 52 63 252 161 779 637 Water 2.0 0.4 2 2 599 599 118 118 Bitterbrush 1.4 0.3 46 82 19 11 44 32 Montane shrub 0.5 0.1 36 66 8 7 12 10 Low sagebrush 0.4 0.1 37 44 7 8 13 12 Burned herbaceous 0.3 0 15 18 12 6 15 6 Sagebrush 0.3 0.1 28 28 6 10 7 29 Riparian 0.2 0.1 15 36 7 5 13 7 Rock 0.1 13 3 4 Mountain Big sage 0.1 0 5 8 6 5 8 7 Highly disturbed land 0 1 28 Agricultural 0 0 1 2 7 27 12 Annual grassland 0 0 2 2 2 15 0 13

Hells Canyon Complex Page 165 Effects of Road and Transmission Line Idaho Power Company

Table 71. Wallowa Whitman National Forest composition of cover types intersecting the transmission line rights-of-way (ROW) and comparison areas (1 km out from either side of the ROW). Cover types present but contributing less than 0.1% to dominance are shown as 0.

Patch Size Standard Dominance (%) Number of Patches Mean Patch Size (ha) Deviation (ha)

East or West or East or West or East or West or East or West or Cover Type North ROW South North ROW South North ROW South North ROW South

Wet forest 37.2 36.7 63.1 22 14 10 970 1,465 6,182 3,448 4,241 17,230

Perennial grass 33.6 31.9 19.1 43 30 42 448 594 444 1,535 1,817 1,556

Dry forest 28.1 29.6 16.7 23 18 25 701 919 653 2,944 3,301 2,832

Riparian 0.9 0.9 0.5 1 5 1 495 99 495 198

Rock 0.6 0.3 1 1 335 335

Montane shrub 0.2 0.3 0.3 11 39 11 11 4 28 7 11 51

Agricultural 0 1 20

Dry meadow 0 12 1 1 Perennial grass montane 0 0 1 1 10 7

Deciduous forest 0 0 1 1 5 5

Alpine shrub 0 7 1 1

Low disturbed land 0 1 5

Wet meadow 0 1 1

Lodgepole pine 0 1 10

Page 166 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line

Table 72. Activity Index ratings for Hells Canyon Complex transmission lines.

Activity Index Activity Category Index Value Line No. Line Name Highest 19.0 923 Borah to Brady Moderate 14.4 910 Hells Canyon to Pallette Junction 12.4 908 Pallette Junction to Imnaha 10.3 952 Midpoint to Adelaide Tap 9.7 907 Oxbow to Pallette Junction Moderately 7.8 913 Pallette Junction to Enterprise Low 7.1 945 Oxbow to Hells Canyon

5.7 905 Brownlee to Oxbow 5.6 903 Brownlee to Quartz Junction (Baker City) Low 3.6 951 Midpoint to Borah 3.1 906 Boise to Midpoint #2 1.7 912 Boise to Midpoint #3 1.4 904 Brownlee to Boise #1&2 1.2 911 Brownlee to Boise #3&4

Table 73. Number of service road and tower survey units and rare plant and noxious weed occurrences, by risk category, associated with Hells Canyon Complex transmission.

Rare Plants Noxious Weeds No. Survey Mean Risk No. No. No. Units with Occurences Risk Index Index Survey Survey No. Survey No. Multiple per Survey Category Value Units Units Occurences Units Occurences Occurences Unit

Highest 2.1 - 4.0 37 1 2 37 133 32 3.6 Moderate 1.6 - 2.0 178 16 17 163 360 90 2.0 Moderately 1.0 - 1.5 340 20 21 264 401 107 1.2 Low Low < 1.0 155 12 13 81 103 20 0.6

Hells Canyon Complex Page 167 Effects of Road and Transmission Line Idaho Power Company

Table 74. Distribution of survey unit Risk Index ratings for each Hells Canyon Complex transmission line.

Number of Survey Units Total Line Number of Moderately Number Survey Units Low Low Moderate Highest 903 93 15 38 35 5 904 118 17 77 22 2 905 57 0 43 13 1 906 77 38 39 0 0 907 73 0 14 42 17 908 19 0 0 10 9 910 13 0 3 9 1 911 100 22 44 33 1 912 122 59 46 16 1 913 26 0 20 5 1 951 12 4 8 0 0

Page 168 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line

Table 75. Rare plant occurrences located on Hells Canyon Complex transmission-line service road survey units with moderate or highest Risk Index Categories.

Survey Abundance Abundance Risk Index Species Unit in Roadwaya in Buffer Zonea Value

Astragalus atratus var. inseptus 912-200-A1 LO LF 1.6

Astragalus atratus var. inseptus 912-344-A1 O F 1.6

Astragalus atratus var. inseptus 912-373-A1 — LO 2

Astragalus atratus var. inseptus 912-395-A1 — LO 1.6

Astragalus atratus var. inseptus 912-517-A1 LR LF 1.6

Astragalus atratus var. owyheensis 903-030-A1 — R 1.6

Bolandra oregana 908-147-A1 — LR 2.3

Carex backii 907-042-A1 LA — 2

Carex backii 907-071-A1 LR LR 2

Carex backii 907-093-A1 — LO 1.6

Carex backii 907-094-A1 LO O 2

Carex backii 907-102-A1 LF — 2

Carex backii 908-126-A2 — LR 2

Carex backii 908-147-A1 — LR 2.3

Carex backii 910-141-A1 R — —

Stylocline filaginea 904-154-A1 — LO 1.6

Stylocline filaginea 911-101-A1 LO LO 1.6

Stylocline filaginea 911-181-A1 LO — 1.6

Stylocline filaginea 911-249-A1 LO — 1.6

Stylocline filaginea 912-344-A1 — LF 1.6 a Abundance: R = rare; LR = locally rare; O = occasional; LO = locally occasional; F = frequent; LF = locally frequent; A = abundant; LA = locally abundant. A “—“ indicates not present.

Hells Canyon Complex Page 169 Effects of Road and Transmission Line Idaho Power Company

Table 76. Meters of cover types in forest region Hells Canyon Complex transmission- line rights-of-way that are different from cover types outside the rights-of- way.

Transmission Lines All Lines 907 908 910 913 Cover Type Adjacent to Rights-of-Way Cover Type in Rights-of- Non- Non- Non- Non- Non- Way Forest Forest Forest Forest Forest Forest Forest Forest Forest Forest Montane shrub 12,606 2,535 4,309 1,880 1,184 4,106 218 3,007 438 Alpine shrub 1,599 249 610 21 989 228 Dry meadow 2,591 1,732 816 1,273 1,775 459 Riverine riparian 1,511 1,511 Perennial grassland 51 399 51 399 Wet meadow 384 384 Shrub riparian 104 44 104 44 Herbaceous riparian 45 12 45 12 Big sagebrush 15 15 Total meters 16,997 6,880 5,889 5,469 1,184 0 4,106 361 5,817 1,151

Page 170 Hells Canyon Complex Idaho Power Company Effects of Road and Transmission Line

Table 77. Snag, large tree, and log characteristics in two zones adjacent to Hells Canyon Complex transmission lines rights-of-way in the forested region of the Wallowa Whitman National Forest.

Mean Total Mean / Plot Mean dbh Height or Sample Counted (SD) Mean / ha Variance (cm) (SD)a Length (m) Sizeb Snags Hazard zone 21 1.1 (1.5) 3.5 24 56 (26) 16 38 Control zone 42 2.1 (2.6) 7.0 76 50 (19) 13 70 Large Trees Hazard zone 133 6.7 (5.0) 22.2 275 62 (13) 32 21 Control zone 140 7.0 (5.8) 23.3 370 63 (13) 32 21 Logs Hazard zone 154 7.2 (7.2) 24 581 23 30 Control zone 166 7.8 (6.0) 26 395 10 20 a dbh is diameter at breast height, 137cm (4.5 feet). SD is the standard deviation around the mean. b Sample size needed for an estimate within 20% of the true mean. Twenty samples were taken for the pilot study.

Table 78. Meters of riparian habitat and proportion trimmed/cut on public land transmission line rights-of-way for the Hells Canyon Complex.

Riparian Cover Type

Deciduous Wet All Types No. of Riparian Line Riverine Trees Shrubs Meadow Riparian Locations Trimmed / Cut (%) 903 41 41 1 904 107 90 624 821 18 60 (7) 905 94 775 869 22 906 35 35 1 907a 2,780 347 426 3,553 24 1,288 (36) 908 280 28 308 2 910 16 30 46 2 911 1,188 497 1,402 3,088 15 60 (2) 912 100 630 730 3 913 25 25 1 923 77 61 138 2 30 (22) 945 45 23 68 3 24 (35) All Lines 4,612 676 3,342 1,091 9,721 94 1,461 (15)

a See text for a more precise description of the extent of riparian present and trimmed on Line 907 in the Imnaha River corridor.

Hells Canyon Complex Page 171 Effects of Road and Transmission Line Idaho Power Company

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