APPENDIX G 

OREGON LNG SOILS, WETLANDS, AND WATERBODY INFORMATION

Appendix G1: Wetlands and Waterbodies Crossed by the Oregon LNG Pipeline 

Appendix G2: Landslide Hazard Areas Crossed by the Oregon LNG Pipeline 

Appendix G3: Site-specific Waterbody Crossing Plans 

Appendix G4: Stream Channel Assessment and Scour Analysis 

Appendix G5: Riparian Areas Crossed by the Oregon LNG Pipeline 

Appendix G6: Landslide and Debris Flow Risk Near Waterbody Crossings

 

APPENDIX G1 

WETLANDS AND WATERBODIES CROSSED 

BY THE OREGON LNG PIPELINE 

Facility Type Wetland ID

Cowardin 

Classification a HGM b Offsite Mapping c

Permanent 

Wetland 

Impact d 

(acres) 

Temporary 

Wetland 

Impact e 

(acres)

Total 

Construction 

Disturbance 

(acres)

Terminal W4BCL01 PSS Depressional N 2.962 0.129 3.091

W4BCL02 PSS Depressional N 0.076 0.000 0.076

W4BCL03 PSS Depressional N 0.135 0.000 0.135

W4BCL04 PSS Depressional N 0.313 0.000 0.313

W4BCL05 E2EM Estuarine Fringe N 26.748 0.827 27.575

W4BCL06 E2EM Estuarine Fringe N 0.012 0.006 0.018

W4BCL07 E2EM Estuarine Fringe N 0.489 0.121 0.610

W4BCL08 E2EM Estuarine Fringe N 0.293 0.017 0.310

W4BCL09 E2EM Depressional N 0.028 0.000 0.028

W4BCL11 E2EM Estuarine Fringe N 0.015 0.035 0.050

W4BCL12 E2EM Estuarine Fringe N 0.023 0.000 0.023

W5BCL016 E2EM Estuarine Fringe N 0.461 0.307 0.768

W5BCL020 PEM Depressional N 0.178 0.000 0.178

W5BCL048 PEM Depressional N 0.330 0.001 0.331

W5BCL049A PSS Depressional N 0.694 0.008 0.702

W5BCL059 PEM Estuarine Fringe N 0.010 0.012 0.022

Terminal Subtotal 32.767 1.463 34.230

Access Road W5BCL020 PEM Depressional N 0.012 0.042 0.054

W5BCL021 PEM Depressional N 0.397 0.199 0.596

W5BCL023 PEM Depressional N 0.507 0.382 0.889

W5BCL084 PFO Depressional N 0.001 0.000 0.001

W5BCL085 PFO Depressional N 0.160 0.000 0.160

W5BCL086 PSS Depressional N 0.028 0.013 0.041

Access Road Subtotal 1.105 0.636 1.741

Terminal Total 33.872 2.099 35.971

Nonjursidictional Facilities

Effluent & Potable Water Lines W5BCL019 PEM Depressional N 0.000 0.299 0.299

W5BCL023 PEM Depressional N 0.000 0.033 0.033

Potable Water Line W99CL0002 PFO/SS TBD Y 0.040 0.000 0.040

W99CL0003 PEM/SS TBD Y 0.000 0.029 0.029

W99CL0004 PSS TBD Y 0.000 0.014 0.014

W99CL0005 PEM TBD Y 0.000 0.187 0.187

W99CL0007 PFO TBD Y 0.002 0.000 0.002

Effluent and Potable Water Line Subtotal 0.042 0.23 0.272

HDD Drill Area W99CL0005 PEM TBD Y 0.000 0.013 0.013

W99CL0006 PFO TBD Y 0.104 0.000 0.104

W99CL0007 PFO TBD Y 0.892 0.000 0.892

W99CL0008 PEM TBD Y 0.000 0.026 0.026

HDD Pullback W5BCL019 PEM Depressional N 0.000 0.049 0.049

W5BCL020 PEM Depressional N 0.000 0.296 0.296

W5BCL021 PEM Depressional N 0.000 0.037 0.037

W5BCL023 PEM Depressional N 0.000 0.079 0.079

HDD Drill Area and Pullback Subtotal 0.996 0.500 1.496

Nonjursidictional Facilities Total 1.038 0.730 1.768

__________

a

 Cowardin Classification System: PEM = palustrine emergent; PSS = palustrine scrub-shrub; PFO = palustrine forested, E2EM=estuarine emergent. b

 Wetland classes based on Hydrogeomorphic Assessment Guidebook for Tidal Wetlands of the Oregon Coast, TBD = to be determined due to lack of site access. c

 Y = Oregon LNG surveyed wetland, N = no site access – proxy data used.

e

 Permanent impacts on wetlands requiring long term restoration including the functional conversion of forested wetlands to scrub-shrub wetlands, or conversation of scru

shrub wetlands to emergent wetlands.

f

 Temporary impacts on wetlands that are expected to recover to preconstruction conditions.

Table G1-1

Wetlands Impacted by Terminal and Associated Facilities

G1‐1
MP Wetland ID 

Cowardian 

Classification a HGM b County/State Tax Lot 

Offsite 

Mapping c

Length of 

pipeline 

(feet) d

Permanent

Wetland 

Impact 

(acres) e

Temporary

Wetland

Impact

(acres) f

Tota

Constru

Disturba

(acre

0.1 W5BCL050 PSS Depressional CLATSOP, OR 08N10W15D001600 N 141 0.1 0.2 0.1 W5BCL058 PEM Depressional CLATSOP, OR 08N10W15D001600 N 327 0.0 0.7 0.2 W5BCL021 PEM Depressional CLATSOP, OR 08N10W22AC01000 N 310 0.0 1.5 0.2 W5BCL052 PEM Depressional-Fringe CLATSOP, OR 08N10W15D001600 N 504 0.0 1.1 0.8 W99CL0021 E2USN Estuarine CLATSOP, OR 08N10W23BD00600 Y 1774 0.0 5.1 0.8 W99CL0021A PEM TBD CLATSOP, OR 08N10W23BD00600 Y 960 0.0 3.4 1.3 W5BCL015A AW TBD CLATSOP, OR 08N10W230000200 N 718 0.0 1.2 1.3 W5BCL015K PSS Depressional CLATSOP, OR 08N10W230000200 N 21 0.0 0.0 1.4 W5BCL015L PSS Depressional CLATSOP, OR 08N10W230000200 N 258 0.2 0.3 1.4 W5BCL015N PSS Depressional CLATSOP, OR 08N10W230000200 N 103 0.1 0.1 1.5 W5BCL015Q PSS Depressional CLATSOP, OR 08N10W230000200 N 110 0.1 0.1 1.5 W5BCL015R PSS Depressional CLATSOP, OR 08N10W260000500 N 44 0.0 0.1 1.6 W5BCL015O AW TBD CLATSOP, OR 08N10W260000500 N 933 0.0 3.0 1.7 W5BCL060 AW Depressional CLATSOP, OR 08N10W260000500 N 486 0.0 1.6 1.8 W5BCL061 PSS Depressional CLATSOP, OR 08N10W260000500 N 255 0.2 0.4 1.8 W99CL200 PSS TBD CLATSOP, OR 08N10W260000401 Y 115 0.2 0.3 2.0 W5BCL062 AW Depressional CLATSOP, OR 08N10W260000500 N 0 0.0 0.0 2.0 W99CL201 PFO TBD CLATSOP, OR 08N10W260000800 Y 937 2.2 0.0 2.3 W99CL202 PSS TBD CLATSOP, OR 08N10W250000500 Y 235 0.2 0.6 2.4 W38CL083 PEM TBD CLATSOP, OR 08N10W250000500 Y 0 0.0 0.0 2.4 W5BCL066 PEM Depressional CLATSOP, OR 08N10W250000400 N 239 0.0 1.1 2.5 W5BCL067 PSS Depressional CLATSOP, OR 08N10W250000400 N 513 0.4 0.6 2.7 W40CL001 PSS TBD CLATSOP, OR 08N10W250000400 Y 1464 1.0 2.6 3.3 W40CL010 AW TBD CLATSOP, OR 08N10W250001500 Y 327 0.0 1.9 3.4 W40CL011 AW TBD CLATSOP, OR 08N10W250001500 Y 175 0.0 0.3 3.4 W99CL026 AW TBD CLATSOP, OR 08N10W250001500 Y 161 0.0 0.3 3.5 W99CL077B AW TBD CLATSOP, OR 08N10W250001500 Y 143 0.0 0.3 3.6 W99CL030 PEM TBD CLATSOP, OR 08N10W360000200 Y 72 0.0 0.1 3.7 W99CL033 PFO TBD CLATSOP, OR 08N10W360000300 Y 365 0.5 0.0 3.7 W99CL077A AW TBD CLATSOP, OR 08N10W360000200 Y 1249 0.0 3.3 3.8 W99CL017 AW TBD CLATSOP, OR 08N10W360000300 Y 492 0.0 1.1 3.8 W99CL076 AW TBD CLATSOP, OR 08N10W360000300 Y 154 0.0 0.4 4.2 W5BCL042F AW TBD CLATSOP, OR 08N10W360001800 N 1800 0.0 5.4 4.5 W42CL001 PEM TBD CLATSOP, OR 08N10W360001800 Y 1423 0.0 5.1 4.5 W5BCL042A AW TBD CLATSOP, OR 07N10W010000200 N 0 0.0 0.0 4.5 W5BCL073 PFO TBD CLATSOP, OR 08N10W360001706 N 0 0.0 0.0 4.6 W5BCL042C AW TBD CLATSOP, OR

07N10W000000100 WATER N 561 0.0 1.8 

4.6 W5BCL043 PEM Depressional CLATSOP, OR 07N10W010000200 N 400 0.0 1.0 

Lower Columbia HUC 4 Subbasin - Clatsop County, Oregon

Table G1-2

Wetlands Crossed by the Oregon LNG Pipeline 

G1‐2
MP Wetland ID 

Cowardian 

Classification a HGM b County/State Tax Lot 

Offsite 

Mapping c

Length of 

pipeline 

(feet) d

Permanent

Wetland 

Impact 

(acres) e

Temporary

Wetland

Impact

(acres) f

Tota

Constru

Disturba

(acre

Table G1-2

Wetlands Crossed by the Oregon LNG Pipeline 

4.7 W42CL002 AW TBD CLATSOP, OR 07N10W010000500 Y 656 0.0 1.7 4.8 W5BCL044 PEM Depressional CLATSOP, OR 07N10W010001003 N 7 0.0 0.0 4.9 W5BCL042D AW TBD CLATSOP, OR 07N10W010001003 N 147 0.0 0.4 5.0 W40CL016 AW TBD CLATSOP, OR 07N10W010001003 Y 689 0.0 1.6 5.0 W40CL018 PFO TBD CLATSOP, OR 07N10W010001003 Y 0 0.1 0.0 5.1 W39CL004 AW TBD CLATSOP, OR 07N10W010001003 Y 100 0.0 1.0 5.5 W40CL023 AW TBD CLATSOP, OR 07N09W060001500 Y 241 0.0 4.0 5.5 W99CL074 AW TBD CLATSOP, OR 07N09W060001500 Y 289 0.0 1.1 5.6 W99CL073 AW TBD CLATSOP, OR 07N09W060001500 Y 301 0.0 1.4 6.2 W5BCL047 PEM Depressional CLATSOP, OR 07N10W120000500 N 67 0.0 0.1 6.3 W38CL007B PEM TBD CLATSOP, OR 07N10W120003000 Y 312 0.0 0.9 7.9 W1BCL001 PFO Slope CLATSOP, OR 07N10W130000801 N 222 0.4 0.0 8.0 W1BCL002 PEM Riverine CLATSOP, OR 07N10W240000100 N 146 0.0 0.2 8.0 W1BCL003 PEM Slope CLATSOP, OR 07N10W240000100 N 0 0.0 0.0 8.1 W1BCL005 PEM Slope CLATSOP, OR 07N10W240000100 N 0 0.0 0.0 8.8 W1BCL008 PEM Riverine CLATSOP, OR 07N10W240000100 N 111 0.0 0.2 

10.2 W1BCL011 PEM Slope CLATSOP, OR 07N10W360000100 N 135 0.0 0.2 10.2 W1BCL023 PEM Flats CLATSOP, OR 07N10W360000100 N 150 0.0 0.2 10.3 W1BCL022 PSS Flats CLATSOP, OR 07N10W360000100 N 60 0.0 0.1 10.9 W39CL006 PEM TBD CLATSOP, OR 07N09W310000400 Y 10 0.0 0.0 10.9 W99CL004 PEM TBD CLATSOP, OR 07N09W310000400 Y 143 0.0 0.7 10.9 W99CL007 PEM TBD CLATSOP, OR 07N09W310000500 Y 279 0.0 0.9 12.3 W1BCL032 PEM Flats CLATSOP, OR 06N09W000000600 N 123 0.0 0.2 12.3 W1BCL033 PEM Flats CLATSOP, OR 07N09W000000300 N 141 0.0 0.2 12.4 W1BCL030 PEM Flats CLATSOP, OR 06N09W000000600 N 59 0.0 0.1 12.4 W1BCL031 PEM Flats CLATSOP, OR 06N09W000000600 N 0 0.0 0.0 12.5 W1BCL025 PEM Riverine CLATSOP, OR 06N09W000000600 N 40 0.0 0.0 12.5 W1BCL028 PEM Slope CLATSOP, OR 06N09W000000600 N 0 0.0 0.0 12.5 W1BCL029 PEM Flats CLATSOP, OR 06N09W000000600 N 0 0.0 0.1 13.1 W1BCL035 PSS Slope CLATSOP, OR 06N09W000000600 N 102 0.1 0.1 13.1 W1BCL037 PEM Slope CLATSOP, OR 06N09W000000600 N 0 0.0 0.0 13.2 W1BCL036 PSS Slope CLATSOP, OR 06N09W000000600 N 244 0.2 0.3 15.1 W5BCL080 PEM Depressional CLATSOP, OR 06N09W000000600 N 17 0.0 0.0 15.8 W5BCL005 PEM Depressional CLATSOP, OR 06N09W360000100 N 2 0.0 0.0 15.9 W5BCL006 PEM Depressional CLATSOP, OR 06N09W360000100 N 0 0.0 0.0 15.9 W5BCL007 PEM Depressional CLATSOP, OR 06N09W000000000 N 162 0.0 0.3 15.9 W5BCL008 PEM Depressional CLATSOP, OR 06N09W000000000 N 47 0.0 0.1 15.9 W5BCL009 PEM Depressional CLATSOP, OR 06N09W360000100 N 0 0.0 0.0 16.0 W5BCL010 PEM Depressional CLATSOP, OR 06N09W360000100 N 6 0.0 0.0 16.0 W5BCL011 PEM Depressional CLATSOP, OR 06N09W000000000 N 66 0.0 0.1 

G1‐3
MP Wetland ID 

Cowardian 

Classification a HGM b County/State Tax Lot 

Offsite 

Mapping c

Length of 

pipeline 

(feet) d

Permanent

Wetland 

Impact 

(acres) e

Temporary

Wetland

Impact

(acres) f

Tota

Constru

Disturba

(acre

Table G1-2

Wetlands Crossed by the Oregon LNG Pipeline 

16.6 W5BCL012B PEM TBD CLATSOP, OR 06N09W360000100 N 0 0.0 0.0 17.8 W5BCL070 PEM Riverine CLATSOP, OR 06N09W360000100 N 63 0.0 0.1 17.8 W5BCL071 PEM Depressional CLATSOP, OR 06N09W360000100 N 0 0.0 0.0 18.3 W5BCL069 PSS Depressional CLATSOP, OR 06N08W000001800 N 0 0.0 0.0 18.4 W5BCL068 PEM Riverine CLATSOP, OR 06N08W000001800 N 0 0.0 0.0 18.6 W1BCL012 PFO Riverine CLATSOP, OR 06N08W000001800 N 71 0.1 0.0 18.6 W1BCL014 PFO Flats CLATSOP, OR 06N08W000001800 N 193 0.3 0.0 18.9 W1BCL015 PFO Slope CLATSOP, OR 06N08W000003400 N 19 0.0 0.0 19.0 W1BCL016 PFO Slope CLATSOP, OR 06N08W000003400 N 0 0.0 0.0 19.0 W1BCL018 PFO Slope CLATSOP, OR 06N08W000003700 N 0 0.0 0.0 19.0 W1BCL019 PEM Slope CLATSOP, OR 06N08W000003700 Y 0 0.0 0.0 19.3 W1BCL020 PEM Riverine CLATSOP, OR 06N08W000003400 N 97 0.0 0.1 19.3 W1BCL021 PFO Slope CLATSOP, OR 06N08W000003300 N 0 0.0 0.0 19.4 W7BCL004 PEM Slope CLATSOP, OR 06N08W000003400 N 9 0.0 0.0 19.6 W2BCL008 PFO Riverine CLATSOP, OR 06N08W000003400 N 245 0.4 0.0 19.7 W2BCL009 PEM Slope CLATSOP, OR 06N08W000003300 N 174 0.0 0.3 19.8 W2BCL007 PEM Slope CLATSOP, OR 06N08W160002000 N 0 0.0 0.0 22.1 W5BCL028 PEM Riverine CLATSOP, OR 06N08W160002000 N 67 0.0 0.1 22.4 W7BCL006 PFO Slope CLATSOP, OR 06N08W160002000 N 40 0.1 0.0 22.5 W6BCL003 PFO Riverine CLATSOP, OR 06N08W160002000 N 63 0.1 0.0 22.6 W6BCL002 PEM Riverine CLATSOP, OR 06N08W160002000 N 41 0.0 0.1 24.4 W5BCL001 PEM Slope CLATSOP, OR 06N08W260004100 N 25 0.0 0.0 24.8 W2BCL001 PSS Depressional CLATSOP, OR 06N08W260004100 N 60 0.0 0.1 24.9 W2BCL002 PEM Slope CLATSOP, OR 06N08W260004100 N 46 0.0 0.1 25.3 W2BCL003A PEM Riverine CLATSOP, OR 06N08W260004100 N 10 0.0 0.0 25.3 W2BCL004A PEM Riverine CLATSOP, OR 06N08W260004100 N 0 0.0 0.0 25.9 W2BCL006 PEM Riverine CLATSOP, OR 06N08W260004100 N 24 0.0 0.0 26.8 W5BCL003 PEM Slope CLATSOP, OR 05N08W010000100 N 0 0.0 0.0 27.3 W5BCL002 PEM Slope CLATSOP, OR 05N08W010000100 N 0 0.0 0.0 27.3 W5BCL078 PEM Depressional CLATSOP, OR 05N08W010000100 N 10 0.0 0.0 30.1 W6BCL001 PEM Depressional CLATSOP, OR 05N07W000000500 N 30 0.0 0.1 30.5 W1BCL039 PEM Flats CLATSOP, OR 05N07W000000500 N 41 0.0 0.0 30.7 W2BCL019 PEM Depressional CLATSOP, OR 05N07W000000500 N 0 0.0 0.0 31.3 W2BCL018 PEM Slope CLATSOP, OR 05N07W000000500 N 38 0.0 0.1 31.4 W2BCL017 PEM Riverine CLATSOP, OR 05N07W000000500 N 38 0.0 0.0 32.5 W3BCL001 PEM Slope CLATSOP, OR 05N07W000002500 N 42 0.0 0.1 33.8 W99CL102 PSS TBD CLATSOP, OR 05N07W330000300 Y 132 0.1 0.1 33.9 W39CL013 AW TBD CLATSOP, OR 05N07W330000300 Y 0 0.0 0.2 33.9 W39CL014 AW TBD CLATSOP, OR 05N07W330000300 Y 139 0.0 0.6 

Nehalem HUC 4 Subasin - Clatsop County, OR 

G1‐4
MP Wetland ID 

Cowardian 

Classification a HGM b County/State Tax Lot 

Offsite 

Mapping c

Length of 

pipeline 

(feet) d

Permanent

Wetland 

Impact 

(acres) e

Temporary

Wetland

Impact

(acres) f

Tota

Constru

Disturba

(acre

Table G1-2

Wetlands Crossed by the Oregon LNG Pipeline 

34.0 W39CL015 AW TBD CLATSOP, OR 05N07W330000300 Y 406 0.0 1.1 34.1 W99CL002 AW TBD CLATSOP, OR 05N07W330000300 Y 387 0.0 0.8 34.4 W5BCL026 PEM Riverine CLATSOP, OR 05N07W330000700 N 0 0.0 0.0 36.3 W3BCL101 PSS/PFO TBD CLATSOP, OR 04N07W000000400 N 458 1.0 0.0 36.5 W3BCL100 PSS/PFO TBD CLATSOP, OR 04N07W000000300 N 92 0.1 0.0 36.7 W3BCL101b PSS/PFO TBD CLATSOP, OR 04N07W000000400 N 2169 5.3 0.0 37.1 W3BCL003 PFO Slope CLATSOP, OR 04N07W000000102 N 29 0.1 0.0 37.2 W3BCL002 PFO Slope CLATSOP, OR 04N07W000000102 N 38 0.1 0.0 37.6 W8BCL004 PEM Slope CLATSOP, OR 04N07W000000100 N 803 0.0 1.4 38.3 W8BCL003 PSS Depressional CLATSOP, OR 04N07W000000100 N 42 0.0 0.0 38.4 W8BCL002 PSS Depressional CLATSOP, OR 04N07W000000100 N 43 0.0 0.0 38.5 W8BCL001 PSS Depressional CLATSOP, OR 04N07W000000100 N 50 0.0 0.0 39.1 W2BCL030B PEM Riverine CLATSOP, OR 04N07W130000304 N 16 0.0 0.0 39.3 W2BCL028 PEM Riverine CLATSOP, OR 04N07W130000304 N 124 0.0 0.2 39.5 W2BCL026 PEM Slope CLATSOP, OR 04N07W130000304 N 128 0.0 0.2 39.6 W1BCL050A PFO Slope CLATSOP, OR 04N07W000002500 N 462 0.8 0.0 40.6 W8BCL030 PEM TBD CLATSOP, OR ROW N 153 0.0 0.2 40.9 W8BCL007C PSS TBD CLATSOP, OR 04N06W000001000 N 101 0.1 0.1 41.4 W8BCL011A PFO TBD CLATSOP, OR 04N06W000000607 N 0 0.0 0.0 41.5 W8BCL011B PFO TBD CLATSOP, OR 04N06W000000607 N 108 0.2 0.0 41.6 W8BCL012 PFO Depressional CLATSOP, OR 04N06W000000607 N 87 0.2 0.0 41.7 W8BCL013 PFO Depressional CLATSOP, OR 04N06W000000607 N 80 0.1 0.0 41.9 W8BCL014 PSS Depressional CLATSOP, OR 04N06W000000603 N 152 0.1 0.2 42.0 W8BCL015 PSS Depressional CLATSOP, OR 04N06W000000603 N 86 0.1 0.1 42.2 W8BCL017 PSS Depressional CLATSOP, OR 04N06W000000603 N 133 0.1 0.0 42.3 W8BCL018 PFO Riverine CLATSOP, OR 04N06W000000603 N 292 0.5 0.0 42.6 W1BCL040 PEM Riverine CLATSOP, OR 04N06W000000603 N 0 0.0 0.0 43.0 W1BCL042 PEM Slope CLATSOP, OR 04N06W000000603 N 0 0.0 0.0 43.7 W1BCL045 PEM Riverine CLATSOP, OR 04N06W000000600 N 0 0.0 0.0 43.9 W1BCL046 PEM Riverine CLATSOP, OR 04N06W000000600 N 63 0.0 0.1 44.0 W1BCL047 PEM Riverine CLATSOP, OR ROW N 0 0.0 0.0 44.2 W1BTI001 PFO Riverine TILLAMOOK, OR 03N06W000099980 N 69 0.1 0.0 44.3 W1BTI002 PEM Riverine TILLAMOOK, OR 03N06W000099980 N 0 0.0 0.0 44.8 W5BTI003 PEM Riverine TILLAMOOK, OR 03N06W000004600 N 0 0.0 0.0 45.5 W1BTI004 PEM Slope TILLAMOOK, OR 03N06W000000800 N 58 0.0 0.1 47.4 W5BTI001 PEM Depressional TILLAMOOK, OR 03N06W000000100 N 49 0.0 0.1 47.6 W6BCO004 PFO Riverine COLUMBIA, OR 04N05W000004000 N 31 0.1 0.0 48.3 W1BCO001 PEM Depressional COLUMBIA, OR 04N05W000003900 N 0 0.0 0.0 48.3 W1BCO002 PSS Depressional COLUMBIA, OR 04N05W000003900 N 0 0.0 0.0 

Nehalem HUC 4 Subasin - Tillamook County, OR 

G1‐5
MP Wetland ID 

Cowardian 

Classification a HGM b County/State Tax Lot 

Offsite 

Mapping c

Length of 

pipeline 

(feet) d

Permanent

Wetland 

Impact 

(acres) e

Temporary

Wetland

Impact

(acres) f

Tota

Constru

Disturba

(acre

Table G1-2

Wetlands Crossed by the Oregon LNG Pipeline 

49.4 W4BCO001 PEM Depressional COLUMBIA, OR 04N05W000003600 N 18 0.0 0.0 50.6 W3BCO111 PFO Slope COLUMBIA, OR 04N05W000003600 N 115 0.1 0.0 50.7 W3BCO113 PEM Slope COLUMBIA, OR 04N05W000003400 N 0 0.0 0.0 50.8 W3BCO112 PFO Slope COLUMBIA, OR 04N05W000003400 N 89 0.1 0.0 53.6 W3BCO002 PSS Riverine COLUMBIA, OR 04N05W000001800 N 1 0.0 0.0 55.1 W4BCO002 PEM Depressional COLUMBIA, OR 04N05W000002100 N 0 0.0 0.0 55.4 W3BCO109 PEM Riverine COLUMBIA, OR 04N05W000000200 N 0 0.0 0.0 55.5 W3BCO110 PEM Depressional COLUMBIA, OR 04N05W000000200 N 0 0.0 0.0 55.8 W3BCO107 PEM Depressional COLUMBIA, OR 04N05W000000200 N 553 0.0 1.0 57.7 W3BCO100 PFO TBD COLUMBIA, OR 05N05W000007800 N 0 0.0 0.0 63.5 W3BCO102 PFO Slope COLUMBIA, OR 05N04W230000600 N 149 0.2 0.0 63.6 W3BCO103 PEM Riverine COLUMBIA, OR 05N04W230000600 N 0 0.0 0.1 63.6 W3BCO103c PEM Riverine COLUMBIA, OR 05N04W230000600 N 174 0.0 0.5 66.3 W3BCO101 PEM Slope COLUMBIA, OR 05N03W190000100 N 110 0.0 0.2 69.1 W6BCO005 PFO Riverine COLUMBIA, OR 05N03W220000200 N 112 0.3 0.0 70.2 W3BCO003 PEM Riverine COLUMBIA, OR 05N03W140000100 N 0 0.0 0.0 71.0 W1BCO020 PEM Depressional COLUMBIA, OR 05N03W140000100 N 0 0.0 0.0 71.1 W1BCO021 PEM Slope COLUMBIA, OR 05N03W130000100 N 0 0.0 0.0 71.2 W1BCO022 PEM Depressional COLUMBIA, OR 05N03W130000100 N 0 0.0 0.0 72.9 W3BCO007 PFO Depressional COLUMBIA, OR 05N02W180000100 N 77 0.3 0.0 73.5 W1BCO023 PFO Riverine COLUMBIA, OR 05N02W170000200 N 72 0.1 0.0 73.6 W1BCO024 PSS Depressional COLUMBIA, OR 05N02W170000200 N 106 0.1 0.1 74.6 W6BCO002 PFO Riverine COLUMBIA, OR 05N02W160000200 N 365 0.7 0.0 74.9 W6BCO001 PFO Riverine COLUMBIA, OR 05N02W160000200 N 21 0.0 0.0 

Lower Columbia Clastskanie HUC 4 Subasin - Columbia County, OR

76.4 W3BCO013 PEM/PFO Riverine COLUMBIA, OR 05N02W150000100 N 92 0.1 0.0 78.4 W3BCO121 PSS Riverine COLUMBIA, OR 05N02W130000100 N 13 0.0 0.0 78.7 W3BCO120 PSS Slope COLUMBIA, OR 05N02W130000100 N 137 0.1 0.1 78.9 W3BCO119 PSS Slope COLUMBIA, OR 05N02W130000100 N 94 0.2 0.0 79.0 W3BCO118 PSS Slope COLUMBIA, OR 05N01W180000500 N 199 0.0 0.3 79.1 W3BCO116 PSS Slope COLUMBIA, OR 05N01W180000500 N 0 0.0 0.0 79.1 W3BCO117 PFO Slope COLUMBIA, OR 05N01W180000500 N 198 0.3 0.0 79.2 W3BCO115 PSS Slope COLUMBIA, OR 05N01W180000500 N 212 0.1 0.1 79.8 W3BCO114A PSS Riverine COLUMBIA, OR 05N01W180000300 N 0 0.0 0.0 79.8 W3BCO114B PSS Riverine COLUMBIA, OR 05N01W180000300 N 60 0.0 0.1 80.2 W5BCO012 PEM Slope COLUMBIA, OR 05N01W170000300 N 0 0.0 0.3 80.2 W99CO001 PEM TBD COLUMBIA, OR 05N01W170000204 Y 126 0.0 0.2 81.4 W5BCO013 PFO Riverine COLUMBIA, OR 05N01W160000100 N 306 0.8 0.0 

Lower Willamette HUC 4 Subbasin - Columbia County, ORLower Columbia Clastskanie HUC 4 Subasin - Columbia County, OR

G1‐6
MP Wetland ID 

Cowardian 

Classification a HGM b County/State Tax Lot 

Offsite 

Mapping c

Length of 

pipeline 

(feet) d

Permanent

Wetland 

Impact 

(acres) e

Temporary

Wetland

Impact

(acres) f

Tota

Constru

Disturba

(acre

Table G1-2

Wetlands Crossed by the Oregon LNG Pipeline 

81.5 W99CO030 PFOA TBD COLUMBIA, OR 05N01W170000200 Y 174 0.6 0.0 81.6 W99CO030 PFO/SSA TBD COLUMBIA, OR 05N01W160000100 Y 132 0.7 0.0 81.6 W99CO031 PEM TBD COLUMBIA, OR 05N01W160000100 Y 475 0.0 1.9 81.7 W3BCO009 PSS Riverine COLUMBIA, OR 05N01W160000201 N 173 0.1 0.1 81.7 W99CO005 PFOA TBD COLUMBIA, OR 05N01W160000100 Y 98 0.5 0.0 81.7 W99CO006 PFO TBD COLUMBIA, OR 05N01W160000100 Y 85 1.2 0.0 

81.7 W99CO007 PFOC TBD COLUMBIA, OR 05N01W160000100 Y 0 0.1 0.0 

81.7 W99CO032 PEM TBD COLUMBIA, OR 05N01W160000201 Y 77 0.0 0.3 82.0 W3BCO008 PEM Riverine COLUMBIA, OR

05N01W1600 WATER N 0 0.0 0.0 

82.7 W99CW001 PEM TBD COWLITZ, WA WB1502002 Y 353 0.0 1.6 83.0 W99CW002 PEM TBD COWLITZ, WA WB1502001 Y 3024 0.0 6.9 84.7 W99CW020 PEM TBD COWLITZ, WA 507810106 Y 0 0.0 0.1 85.8 W99CW022 PEM TBD COWLITZ, WA 50729 Y 765 0.0 2.1 86.6 W99CW011 PEM TBD COWLITZ, WA Y 125 0.0 0.2 

__________

a Cowardin Classification System: PEM = palustrine emergent; PSS = palustrine scrub-shrub; PFO = palustrine forested,E2USN= estuarine unconsoldiated bottom; AW= agriculturab Wetland classes based on Hydrogeomorphic Assessment Guidebook for Tidal Wetlands of the Oregon Coast, TBD = to be determined due to lack of site access.c Y = Oregon LNG surveyed wetland, N = no site access – proxy data used.e Permanent impacts on wetlands requiring long term restoration including the functional conversion of forested wetlands to scrub-shrub wetlands, or conversation of scrub-shrub wf Temporary impacts on wetlands that are expected to recover to preconstruction conditions.g Volumes based on a 10-foot width, 8-foot average depth, and the length of the pipeline through each wetland. Volumes include the temporary excavation of material from the trenc

material to backfill the trench but excludes temporary spoils piles in wetlands from trench excavation or temporary soil disturbances in temporary workspaces from equipment operatioLewis HUC 4 Subasin - Cowlitz County, WALower Columbia Clastskanie HUC 4 Subasin - Cowlitz County, WA

G1‐7
Milepost Stream ID

Stream 

Width 

(feet) Waterbody County/State

Crossing

Method

FERC 

Waterbody

Type

Stream

Type Oregon Stat

1.0 S99CL001 110 Adair Slough CLATSOP, OR HDD Major Perennial Categor

1.5 S5BCL074 20 Vera Creek CLATSOP, OR Flume Intermediate Perennial Categor

2.6 S40CL001 50 Tributary of Lewis and Clark River CLATSOP, OR Open cut Intermediate Perennial Categor

3.1 S40CL002 1250 Lewis and Clark River CLATSOP, OR HDD Major Perennial Categor

3.5 S99CL019 60 Tributary of Jeffers Slough CLATSOP, OR Flume Intermediate Intermittent Categor

4.1 S5BCL059 1.5 Tributary of Barrett Slough CLATSOP, OR Flume Minor Perennial Categor

4.2 S5BCL062 2 Tributary of Barrett Slough CLATSOP, OR Open cut Minor Perennial Categor

4.3 S5BCL063 4.5 Tributary of Barrett Slough CLATSOP, OR Open cut Minor Intermittent Categor

4.5 S5BCL064 12 Barrett Slough CLATSOP, OR Flume Intermediate Intermittent Categor

4.6 S5BCL066 3 Tributary of Barrett Slough CLATSOP, OR Open cut Minor Perennial Categor

4.8 S5BCL068 8 Tributary of Green Slough CLATSOP, OR Open cut Minor Intermittent Categor

4.8 S5BCL069 7 Tributary of Green Slough CLATSOP, OR Open cut Minor Intermittent Categor

4.9 S5BCL070 2 Unnamed CLATSOP, OR Open cut Minor Intermittent NA 

5.0 S5BCL071 5 Unnamed CLATSOP, OR HDD Minor Intermittent NA 

5.2 S5BCL072 7 Tributary of Lewis and Clark River CLATSOP, OR HDD Minor Intermittent Categor

5.2 S99CL111 340 Lewis and Clark River CLATSOP, OR HDD Major Perennial Categor

5.4 S99CL034 20 Tributary of Lewis and Clark River CLATSOP, OR HDD Intermediate Perennial Categor

5.5 S99CL024 13 Tributary of Lewis and Clark River CLATSOP, OR Open cut Intermediate Perennial Categor

5.7 S99CL064 340 Lewis and Clark River CLATSOP, OR HDD Major Intermittent Categor

5.8 S38CL003 8 Tributary of Lewis and Clark River CLATSOP, OR HDD Minor Perennial Categor

7.9 S1BCL001 10 Heckard Creek CLATSOP, OR Flume Intermediate Intermittent Categor

8.1 S1BCL050 10 Unnamed CLATSOP, OR Open cut Intermediate Intermittent NA 8.6 S1BCL002 4 Tributary of Lewis and Clark River CLATSOP, OR Open cut Minor Perennial Categor

8.8 S1BCL018 25 Tributary of Lewis and Clark River CLATSOP, OR Flume Intermediate Intermittent Categor

9.1 S1BCL003 3 Tributary of Lewis and Clark River CLATSOP, OR Open cut Minor Perennial Categor

9.3 S1BCL004 4 Tributary of Lewis and Clark River CLATSOP, OR Open cut Minor Intermittent Categor

9.7 S1BCL006 3 Tributary of Lewis and Clark River CLATSOP, OR Open cut Minor Intermittent Categor

9.7 S1BCL005 8 Tributary of Lewis and Clark River CLATSOP, OR Open cut Minor Intermittent Categor

9.9 S1BCL007 3 Tributary of Lewis and Clark River CLATSOP, OR Open cut Minor Intermittent Categor

10.0 S1BCL008 10 Tributary of Lewis and Clark River CLATSOP, OR Flume Intermediate Intermittent Categor

11.0 S99CL018 35 Lewis and Clark River CLATSOP, OR HDD Intermediate Perennial Categor

12.8 S1BCL016 8 Tributary of Speelyai Creek CLATSOP, OR Flume Minor Perennial Categor

13.8 S5BCL040 0.8 Tributary of Youngs River CLATSOP, OR Flume Minor Perennial Categor

13.8 S5BCL041 2 Tributary of Youngs River CLATSOP, OR Flume Minor Perennial Categor

13.9 S5BCL042 5 Tributary of Youngs River CLATSOP, OR Open cut Minor Perennial Categor

Table G1-3

Waterbodies Crossed by the Oregon LNG Pipeline 

Lower Columbia HUC 4 Subbasin 

G1‐8
Milepost Stream ID

Stream 

Width 

(feet) Waterbody County/State

Crossing

Method

FERC 

Waterbody

Type

Stream

Type Oregon Stat

Table G1-3

Waterbodies Crossed by the Oregon LNG Pipeline 

13.9 S5BCL043 20 Tributary of Youngs River CLATSOP, OR Open cut Intermediate Intermittent Categor

14.1 S5BCL045 8 Tributary of Youngs River CLATSOP, OR Flume Minor Intermittent Categor

14.2 S5BCL044 5 Tributary of Youngs River CLATSOP, OR Flume Minor Perennial Categor

14.8 S5BCL038 2 Tributary of Youngs River CLATSOP, OR Open cut Minor Perennial Categor

15.3 S5BCL035 3 Tributary of Youngs River CLATSOP, OR Open cut Minor Intermittent Categor

15.6 S5BCL030 4 Tributary of Youngs River CLATSOP, OR Flume Minor Intermittent Categor

15.6 S5BCL034 4 Tributary of Youngs River CLATSOP, OR Flume Minor Perennial Categor

15.8 S5BCL031 5 Tributary of Youngs River CLATSOP, OR Flume Minor Perennial Categor

16.1 S99CL016 7 Bayney Creek CLATSOP, OR Flume Minor Perennial Categor

16.6 S5BCL032 3 Tributary of Youngs River CLATSOP, OR Open cut Minor Perennial Categor

17.3 S5BCL077 6 Tributary of Youngs River CLATSOP, OR Flume Minor Intermittent Categor

17.8 S5BCL078 6 Tributary of Youngs River CLATSOP, OR Open cut Minor Perennial Categor

17.8 S5BCL079 5 Tributary of Youngs River CLATSOP, OR Open cut Minor Intermittent Categor

17.9 S5BCL080 4 Tributary of Youngs River CLATSOP, OR Open cut Minor Intermittent Categor

18.4 S5BCL076 4 Tributary of Rock Creek CLATSOP, OR Flume Minor Intermittent Categor

18.5 S1BCL009 10 Rock Creek CLATSOP, OR Flume Intermediate Perennial Category 

18.8 S1BCL010 5 Tributary of Youngs River CLATSOP, OR Open cut Minor Perennial Categor

19.0 S1BCL011 6 Tributary of Youngs River CLATSOP, OR Flume Minor Intermittent Categor

19.1 S1BCO012 3 Unnamed CLATSOP, OR Open cut Minor Perennial NA 19.3 S1BCL014 8 Osgood Creek CLATSOP, OR Flume Minor Intermittent Categor

19.6 S2BCL013A 7 Tributary of Osgood Creek CLATSOP, OR Flume Minor Perennial Categor

20.1 S2BCL013B 35 Fox Creek CLATSOP, OR Flume Intermediate Perennial Categor

21.4 S38CL013 3 South Fork Youngs River CLATSOP, OR Flume Minor Perennial Categor

21.6 S42CL003 3 Unnamed CLATSOP, OR Open cut Minor Perennial NA 21.8 S5BCL058 15 Tributary of Youngs River CLATSOP, OR Flume Intermediate Perennial Categor

22.1 S5BCL049 2.5 Tributary of Youngs River CLATSOP, OR Flume Minor Perennial Categor

22.2 S5BCL048 5 Tributary of Youngs River CLATSOP, OR Open cut Minor Intermittent Categor

22.5 S6BCL016 2 Tributary of Youngs River CLATSOP, OR Open cut Minor Intermittent Categor

22.6 S6BCL014 4 Tributary of Youngs River CLATSOP, OR Open cut Minor Intermittent Categor

22.6 S6BCL013 1 Tributary of Youngs River CLATSOP, OR Open cut Minor Intermittent Categor

22.6 S6BCL015 2 Tributary of Youngs River CLATSOP, OR Open cut Minor Intermittent Categor

22.8 S6BCL017 3.5 Tributary of Youngs River CLATSOP, OR Open cut Minor Intermittent Categor

22.8 S6BCL010 2 Tributary of Youngs River CLATSOP, OR Open cut Minor Intermittent Categor

22.8 S6BCL011 2 Tributary of Youngs River CLATSOP, OR Open cut Minor Intermittent Categor

22.9 S6BCL018 4 Tributary of Fall Creek CLATSOP, OR Open cut Minor Intermittent Categor

23.0 S6BCL019 20 Tributary of Fall Creek CLATSOP, OR Flume Intermediate Perennial Categor

G1‐9
Milepost Stream ID

Stream 

Width 

(feet) Waterbody County/State

Crossing

Method

FERC 

Waterbody

Type

Stream

Type Oregon Stat

Table G1-3

Waterbodies Crossed by the Oregon LNG Pipeline 

23.1 S6BCL020 3 Tributary of Fall Creek CLATSOP, OR Open cut Minor Intermittent Categor

23.4 S38CL014 10 Fall Creek CLATSOP, OR Flume Intermediate Perennial Categor

24.3 S5BCL016 3.5 Tributary of Fishhawk Creek CLATSOP, OR Open cut Minor Intermittent Categor

24.4 S5BCL018 6 Tributary of Fishhawk Creek CLATSOP, OR Flume Minor Perennial Categor

24.4 S5BCL017 3.5 Tributary of Fishhawk Creek CLATSOP, OR Open cut Minor Intermittent Categor

24.8 S2BCL002 25 Tributary of Fishhawk Creek CLATSOP, OR Open cut Intermediate Intermittent Category 24.8 S2BCL001 7 Tributary of Fishhawk Creek CLATSOP, OR Open cut Minor Intermittent Categor

25.1 S2BCL003 8 Tributary of Fishhawk Creek CLATSOP, OR Open cut Minor Intermittent Category 

25.2 S2BCL004 3 Tributary of Fishhawk Creek CLATSOP, OR Open cut Minor Perennial Category 

25.2 S2BCL005 10 Tributary of Fishhawk Creek CLATSOP, OR Flume Intermediate Intermittent Category 25.3 S2BCL007 3 Tributary of Fishhawk Creek CLATSOP, OR Flume Minor Perennial Category 

25.4 S2BCL008A 15 Tributary of Fishhawk Creek CLATSOP, OR Flume Intermediate Perennial Category 25.7 S2BCL009 10 Tributary of Little Fishhawk Creek CLATSOP, OR Flume Intermediate Perennial Category 25.7 S2BCL010 4 Tributary of Little Fishhawk Creek CLATSOP, OR Open cut Minor Intermittent Category 

25.9 S2BCL012 10 Tributary of Little Fishhawk Creek CLATSOP, OR Open cut Intermediate Intermittent Category 26.3 S5BCL019 1.2 Tributary of Little Fishhawk Creek CLATSOP, OR Flume Minor Perennial Category 

26.5 S5BCL029 1.5 Tributary of Little Fishhawk Creek CLATSOP, OR Flume Minor Perennial Category 

26.6 S5BCL027 1 Tributary of Little Fishhawk Creek CLATSOP, OR Flume Minor Perennial Category 

26.6 S5BCL028 2 Tributary of Little Fishhawk Creek CLATSOP, OR Open cut Minor Intermittent Category 

26.8 S5BCL025 1.4 Tributary of Little Fishhawk Creek CLATSOP, OR Flume Minor Perennial Category 

26.8 S5BCL023 1.3 Tributary of Little Fishhawk Creek CLATSOP, OR Flume Minor Perennial Category 

27.0 S5BCL022 3 Tributary of Little Fishhawk Creek CLATSOP, OR Open cut Minor Intermittent Category 

27.2 S5BCL021 6 Tributary of Little Fishhawk Creek CLATSOP, OR Flume Minor Perennial Category 

27.3 S5BCL020 1.8 Tributary of Little Fishhawk Creek CLATSOP, OR Flume Minor Perennial Category 

27.4 S5BCL015 4 Tributary of Little Fishhawk Creek CLATSOP, OR Flume Minor Perennial Category 

27.6 S5BCL014 2.4 Tributary of Little Fishhawk Creek CLATSOP, OR Open cut Minor Intermittent Category 

27.8 S5BCL012 2 Tributary of Little Fishhawk Creek CLATSOP, OR Open cut Minor Intermittent Category 

27.8 S5BCL013 2 Tributary of Little Fishhawk Creek CLATSOP, OR Open cut Minor Intermittent Category 

27.9 S5BCL011 3 Tributary of Little Fishhawk Creek CLATSOP, OR Open cut Minor Intermittent Category 

28.1 S5BCL010 3.5 Tributary of Little Fishhawk Creek CLATSOP, OR Flume Minor Perennial Category 

28.4 S5BCL007 6 Tributary of East Humbug Creek CLATSOP, OR Open cut Minor Intermittent Category 28.5 S5BCL005 4 Tributary of East Humbug Creek CLATSOP, OR Open cut Minor Intermittent Category 28.5 S5BCL004 7 Tributary of East Humbug Creek CLATSOP, OR Open cut Minor Intermittent Category 

29 S5BCL001 3 Tributary of East Humbug Creek CLATSOP, OR Open cut Minor Intermittent Category 

29 S5BCL002 2 Tributary of East Humbug Creek CLATSOP, OR Open cut Minor Intermittent Category 

Nehalem HUC 4 Subasin 

G1‐10
Milepost Stream ID

Stream 

Width 

(feet) Waterbody County/State

Crossing

Method

FERC 

Waterbody

Type

Stream

Type Oregon Stat

Table G1-3

Waterbodies Crossed by the Oregon LNG Pipeline 

29.4 S6BCL007 1 Tributary of East Humbug Creek CLATSOP, OR Open cut Minor Intermittent Category 29.4 S6BCL008 1.5 Tributary of East Humbug Creek CLATSOP, OR Open cut Minor Intermittent Category 29.5 S6BCL005 6 Tributary of East Humbug Creek CLATSOP, OR Flume Minor Perennial Category 29.5 S6BCL006 7 Tributary of East Humbug Creek CLATSOP, OR Flume Minor Perennial Category 29.9 S6BCL004 5 Tributary of East Humbug Creek CLATSOP, OR Open cut Minor Intermittent Category 30.9 S2BCL021 2 Tributary of East Humbug Creek CLATSOP, OR Open cut Minor Intermittent Categor

31.4 S2BCL008B 15 Alder Creek CLATSOP, OR Flume Intermediate Perennial Categor

31.6 S6BCL001 3.5 Tributary of Alder Creek CLATSOP, OR Open cut Minor Intermittent Categor

32 S3BCL002 6 Tributary of Nehalem River CLATSOP, OR Open cut Minor Intermittent Categor32 S3BCL001 6 Tributary of Nehalem River CLATSOP, OR Open cut Minor Intermittent Categor

32.1 S3BCL004 6 Tributary of Nehalem River CLATSOP, OR Open cut Minor Intermittent Categor

32.1 S3BCL003 4 Tributary of Nehalem River CLATSOP, OR Open cut Minor Intermittent Categor

32.3 S3BCL005 8 Tributary of Nehalem River CLATSOP, OR Open cut Minor Intermittent Categor

32.3 S3BCL006 10 Tributary of Nehalem River CLATSOP, OR Open cut Intermediate Intermittent Categor

32.4 S3BCL007 8 Tributary of Nehalem River CLATSOP, OR Open cut Minor Intermittent Categor

33.5 S99CL108 120 Nehalem River CLATSOP, OR HDD Major Perennial Categor

34.4 S5BCL046 2 Tributary of Nehalem River CLATSOP, OR Flume Minor Perennial Categor

36.2 S3BCL101 10 Unnamed CLATSOP, OR Flume Intermediate Perennial NA 

36.3 S3BCL102 5 Unnamed CLATSOP, OR Flume Minor Perennial NA 37.5 S8BCL004 5 Tributary of NF Quartz Creek CLATSOP, OR Flume Minor Perennial Categor37.7 S8BCL003 2.3 Tributary of NF Quartz Creek CLATSOP, OR Open cut Minor Intermittent Categor38.5 S8BCL001 2 Tributary of SF Quartz Creek CLATSOP, OR Flume Minor Perennial Categor39.6 S1BCL029 2.6 Tributary of Military Creek CLATSOP, OR Open cut Minor Intermittent Category 39.8 S1BCL027 1.5 Tributary of Military Creek CLATSOP, OR Open cut Minor Intermittent Category 39.8 S1BCL028 2.6 Tributary of Military Creek CLATSOP, OR Open cut Minor Intermittent Category 

41 S8BCL005 20 Rock Creek CLATSOP, OR HDD Intermediate Perennial Category 

42.3 S8BCL009 11 Tributary of South Fork Rock Creek CLATSOP, OR Flume Intermediate Perennial Category 

42.7 S1BCL020 6 Tributary of South Fork Rock Creek CLATSOP, OR Flume Minor Perennial Category 43.1 S1BCL021 15 South Fork Rock Creek CLATSOP, OR HDD Intermediate Perennial Category 

43.4 S1BCL022 12 Bear Creek CLATSOP, OR HDD Intermediate Perennial Category 

43.5 S1BCL023 1.3 Tributary of Bear Creek CLATSOP, OR HDD Minor Intermittent Category 43.7 S1BCL024 1.6 Tributary of Bear Creek CLATSOP, OR Flume Minor Perennial Category 43.9 S1BCL025 4 Tributary of Bear Creek CLATSOP, OR Open cut Minor Intermittent Category 

44 S1BCL026 3 Tributary of Bear Creek CLATSOP, OR Open cut Minor Intermittent Category 

44.2 S1BTI001 6 Bear Creek Tillamook, OR Flume Minor Perennial Category 44.3 S1BTI002 1.8 Tributary of Bear Creek Tillamook, OR Open cut Minor Intermittent Category 

G1‐11
Milepost Stream ID

Stream 

Width 

(feet) Waterbody County/State

Crossing

Method

FERC 

Waterbody

Type

Stream

Type Oregon Stat

Table G1-3

Waterbodies Crossed by the Oregon LNG Pipeline 

44.8 S5BTI001 8 Tributary of Wolf Creek Tillamook, OR Flume Minor Perennial Category 45.1 S1BTI003 4 Tributary of Wolf Creek Tillamook, OR Open cut Minor Intermittent Category 47.6 S6BCO002 30 North Fork Wolf Creek COLUMBIA, OR Flume Intermediate Perennial

g y

48.3 S1BCO000 3 Tributary of North Fork Wolf Creek COLUMBIA, OR Flume Minor Perennial Categor

50.5 S3BCO012 30 Clear Creek COLUMBIA, OR Flume Intermediate Perennial Categor

53.6 S3BCO002 1 Fall Creek COLUMBIA, OR Flume Minor Perennial NA 55.7 S3BCO107 10 Cedar Creek COLUMBIA, OR Flume Intermediate Perennial NA 

55.8 S3BCO106 4 Tributary of Cedar Creek COLUMBIA, OR Flume Minor Perennial NA 57.7 S3BCO101B 10 Braided Channel to Rock Creek COLUMBIA, OR HDD Intermediate Perennial Category 

57.7 S3BCO100 10 Tributary of Rock Creek COLUMBIA, OR HDD Intermediate Perennial Categor

57.7 S3BCO101 30 Rock Creek COLUMBIA, OR HDD Intermediate Perennial Categor

63.8 S3BCO014 30 Nehalem River COLUMBIA, OR HDD Intermediate Perennial Category 

66.3 S3BCO103 1 Tributary of Oak Ranch Creek COLUMBIA, OR Open cut Minor Intermittent NA 

67.7 S6BCO004 3 Unnamed COLUMBIA, OR Open cut Minor Intermittent NA 

68 S6BCO003 3 Unnamed COLUMBIA, OR Flume Minor Perennial NA 

70.2 S3BCO003 1 Tributary of Clatskanie River COLUMBIA, OR Flume Minor Perennial Categor

70.7 S99CO020 18.5 Clatskanie River COLUMBIA, OR Flume Intermediate Perennial Cat 2, Cat 3, Cat 

71 S99CO021 1 Unnamed COLUMBIA, OR Flume Minor Perennial NA 

71.8 S5BCO001 2 Little Clatskanie River COLUMBIA, OR Flume Minor Perennial Categor

72.7 S3BCO008 2 Tributary of Milton Creek COLUMBIA, OR Flume Minor Perennial/Inte Categor

73 S3BCO010 12 Milton Creek COLUMBIA, OR Flume Intermediate Perennial Category 

73.5 S1BCO004 3 Apilton Creek COLUMBIA, OR Open cut Minor Intermittent NA 73.6 S1BCO005 1 Tributary of Apilton Creek COLUMBIA, OR Open cut Minor Intermittent NA 74.5 S5BCO011 5 Unnamed COLUMBIA, OR Flume Minor Perennial NA 74.6 S5BCO010 30 Unnamed COLUMBIA, OR Flume Intermediate Perennial NA 

74.9 S6BCO001 22 Milton Creek COLUMBIA, OR Flume Intermediate Perennial Categor

Lower Columbia Clastskanie HUC 4 Subasin

76.3 S3BCO110 1 Tributary of Merril Creek COLUMBIA, OR Open cut Minor Intermittent NA 

76.4 S3BCO017 35 Merrill Creek COLUMBIA, OR Flume Intermediate Perennial NA 

78.2 S2BCO009 3 Tributary of Merrill Creek COLUMBIA, OR Open cut Minor Intermittent Categor

78.4 S3BCO122 10 Tributary of Merrill Creek COLUMBIA, OR Flume Intermediate Perennial Categor

79 S3BCO120 1 Tributary of Merrill Creek COLUMBIA, OR Open cut Minor Intermittent Categor

79 S3BCO119 1 Tributary of Merrill Creek COLUMBIA, OR Open cut Minor Intermittent Categor

79.9 S3BCO115 1 Tributary of Merrill Creek COLUMBIA, OR Flume Minor Perennial Categor

Lower Columbia Clastskanie HUC 4 Subasin Lower Willamette HUC 4 Subbasin 

G1‐12
Milepost Stream ID

Stream 

Width 

(feet) Waterbody County/State

Crossing

Method

FERC 

Waterbody

Type

Stream

Type Oregon Stat

Table G1-3

Waterbodies Crossed by the Oregon LNG Pipeline 

81.6 S99CO011 280 Deer Island Slough COLUMBIA, OR Flume Major Perennial Category 

82.0 S3BCO123 20 Dyna Nobel Channel COLUMBIA, OR HDD Intermediate Perennial Categor

82.3 S99CO014 3300 Columbia River COLUMBIA, OR HDD Major Perennial Cat 2, Cat 3, Cat 

83.3 S99CW020 10 Burris Creek COWLITZ, WA Flume Intermediate Perennial NA 

85.8 S99CW021 2 Unnamed COWLITZ, WA Flume Minor Perennial NA 

86 S99CW022 2 Unnamed COWLITZ, WA Flume Minor Perennial NA 

86.5 S99CW023 3 Unnamed COWLITZ, WA Open cut Minor Intermittent NA 

86.7 S99CW025 3 Unnamed COWLITZ, WA Open cut Minor Intermittent NA 

86.8 S99CW026 3 Unnamed COWLITZ, WA Flume Minor Perennial NA 

__________

Category 1: All standards are met. (This category is not used.)Category 2: Attaining - Some of the pollutant standards are met.Category 3: Insufficient data to determine whether a standard is met.

3B: Potential concern - Some data indicate nonattainment of a criterion, but data are insufficient to assign another category.

HDD: horizontal directional drillOpen cut: Conventional Open cut. Applicable to intermittent and ephemeral streams that are not fish-bearing, fish-bearing intermittent or ephemeral streams if dry at the time o

Category 4: Water is water quality limited but a Total Maximum Daily Load (TMDL) is not needed. This category encompasses:

4A: TMDL approved - TMDLs needed to attain applicable water quality standards have been approved.4B: Other pollution control requirements are expected to address all pollutants and will attain water quality standards.4C: Impairment is not caused by a pollutant (e.g., flow or lack of flow is not considered a pollutant).

Category 5: Water is water quality limited and a TMDL is needed, Section 303(d) list.Cat = categoryTMDL = total maximum daily load; NA = not applicable.Precision loss may occur because of rounding.Crossing Method Flume: Water will be diverted around the construction area using a flume or flumes to allow a dry Open cut. If no fish are present, the crossing method may be modified with a d

G1‐13

APPENDIX G2 

LANDSLIDE HAZARD AREAS CROSSED BY THE OREGON LNG

PIPELINE

 G2-1 

Appendix G2 

Landslide Hazard Areas Crossed by the Oregon LNG Pipeline 

Mapped Landslide Hazard a

From MP To MP Type of Landslide Hazard Refere

6.5 7.8 Landslide Topography; Potential Rapidly Moving Landslide; Potential 

Gullying/Erosion/Debris Flow 

Schlicker et al., 1972; Burns et 2002; CH2M HILL, 2009 

8.0 8.6 Landslide Topography Schlicker et al., 1972; Burns et 8.7 10.2 Landslide Topography; Potential Gullying/Erosion/Debris Flow Schlicker et al., 1972; Burns et 11.2 15.6 Inactive Landslide; Landslide Topography; Potential Rapidly Moving Landslide; 

Potential Gullying/Erosion/Debris Flow 

Schlicker et al., 1972; Burns et 2002; CH2M HILL, 2009 

16.5 17.8 Mass Movement Topography, Landslide Topography Schlicker et al., 1972; Burns et 

2009 

17.4 17.6 Potential Rapidly Moving Landslide Hazard Burns et al., 2011; Hofmeister, 17.8 b 21.5 Mass Movement Topography, Landslide Topography; Potential Rapidly Moving 

Landslide; Potential Gullying/Erosion/Debris Flow 

Beaulieu, 1973; Burns et al., 2

21.6 22.1 Potential Rapidly Moving Landslide Hofmeister, 2002 22.1 23.8 Mass Movement Topography; Potential Gullying/Erosion/Debris Flow Beaulieu, 1973; Burns et al., 223.8b 25.3 Mass Movement Topography; Potential Rapidly Moving Landslide; Potential 

Gullying/Erosion/Debris Flow 

Beaulieu, 1973; Burns et al., 2CH2M HILL, 2009 

25.0 25.1 2007–2008 Landslides—2,000 to 3,500 feet from alignment CH2M HILL, 2009 25.3 b 26.2 b Mass Movement Topography Beaulieu, 1973; Burns et al., 226.2 27.2 Potential Gullying/Erosion/Debris Flow CH2M HILL, 2009 26.9 2007–2008 Landslide—1,200 feet from alignment CH2M HILL, 2009 27.3 30.3 Mass Movement Topography; Potential Rapidly Moving Landslide; Potential 

Gullying/Erosion/Debris Flow 

Beaulieu, 1973; Hofmeister, 20

30.7 31.9 b Mass Movement Topography; Potential Rapidly Moving Landslide Beaulieu, 1973; Hofmeister, 2031.9 32.3 Mass Movement Topography Beaulieu, 1973; Burns et al., 233.0 33.3 Mass Movement Topography Beaulieu, 1973; Burns et al., 234.2 37.2 b Mass Movement Topography Beaulieu, 1973; Burns et al., 235.7 Recent Landslide—2,500 feet from alignment Burns et al., 2011 36.1 Recent Landslides—1,300 to 1,500 feet from alignment Burns et al., 2011 37.2 Recent Landslide—1,900 feet from alignment Burns et al., 2011; CH2M HILL37.5 38.1 Potential Rapidly Moving Landslide; Potential Gullying/Erosion/Debris Flow Hofmeister, 2002, CH2M HILL37.7 38.8 Mass Movement Topography Beaulieu, 1973; Burns et al., 238.7 39.0 Potential Rapidly Moving Landslide Hofmeister, 2002 38.8 Recent Landslide—1,300 feet from alignment Burns et al., 2011 39.0 39.8 Potential Gullying/Erosion/Debris Flow CH2M HILL, 2009 40.2 Recent Landslide—400 feet from alignment Burns et al., 2011 40.2 41.0 Potential Rapidly Moving Landslide Hofmeister, 2002 
 G2-2 

Appendix G2 

Landslide Hazard Areas Crossed by the Oregon LNG Pipeline 

Mapped Landslide Hazard a

From MP To MP Type of Landslide Hazard Refere

42.0 42.8 Potential Gullying/Erosion/Debris Flow CH2M HILL, 2009 43.1 43.2 Potential Rapidly Moving Landslide Hofmeister, 2002 41.5 44.7 Mass Movement Topography; Potential Rapidly Moving Landslide Beaulieu, 1973; CH2M HILL, 245.0 Recent Landslide - 300 feet from alignment CH2M HILL, 2013 45.2 Recent Landslide – 300 feet from alignment Burns et al., 2011 45.6 45.6 Potential Gullying/Erosion/Debris Flow, Recent Landslide – 500 feet from alignment CH2M HILL, 2013, Burns et al46.3 b Recent Landslides – 500 feet from alignment Burns et al., 2011 46.5 b Recent Landslide – 400 feet from alignment Burns et al., 2011 46.3 46.6 Mass Movement Topography, Potential Rapidly Moving Landslide Burns et al., 2011; Hofmeister, 46.9 47.3 Mass Movement Topography Burns et al., 2011 47.5 Recent Landslide – 1,500 feet from alignment Burns et al., 2011 47.6 49.0 Landslide Topography, Potential Gullying/Erosion/Debris Flow, Potential Rapidly 

Moving Landslide 

CH2M HILL, 2013; Hofmeister

49.2 49.4 Landslide Topography CH2M HILL, 2013 49.4 b 49.8 b Potential Gullying/Erosion/Debris Flow CH2M HILL, 2013 50.0 50.1 Potential Rapidly Moving Landslide Hofmeister, 2002 50.6 50.6 Potential Rapidly Moving Landslide Hofmeister, 2002 50.8 50.8 Potential Rapidly Moving Landslide Hofmeister, 2002 51.4 51.9 b Landslide Topography, Potential Gullying/Erosion/Debris Flow CH2M HILL, 2013 52.8 52.9 Potential Rapidly Moving Landslide Hofmeister, 2002 53.4 53.6 Potential Rapidly Moving Landslide, Potential Gullying/Erosion/Debris Flow Hofmeister, 2002; CH2M HILL53.8 54.2 Landslide Topography CH2M HILL, 2013 54.6 54.7 Landslide Topography CH2M HILL, 2013 54.9 55.7 Landslide Topography CH2M HILL, 2013 55.9 55.9 Potential Gullying/Erosion/Debris Flow CH2M HILL, 2013 55.9 56.4 Landslide Topography CH2M HILL, 2013 57.4 57.7 Landslide Topography CH2M HILL, 2013 57.8 58.3 Potential Rapidly Moving Landslide, Landslide Topography Hofmeister, 2002; CH2M HILL59.2 59.3 Landslide Topography CH2M HILL, 2013 59.9 60.1 Landslide Topography CH2M HILL, 2013 60.9 61.1 Landslide Topography CH2M HILL, 2013 62.0 62.0 Potential Gullying/Erosion/Debris Flow CH2M HILL, 2013 62.3 62.5 Landslide Topography CH2M HILL, 2013 
 G2-3 

Appendix G2 

Landslide Hazard Areas Crossed by the Oregon LNG Pipeline 

Mapped Landslide Hazard a

From MP To MP Type of Landslide Hazard Refere

62.7 62.7 Potential Rapidly Moving Landslide Hofmeister, 2002 63.4 63.4 Potential Rapidly Moving Landslide Hofmeister, 2002 63.7 Recent Landslide – 2,400 feet from alignment Burns et al., 2011 63.8 Recent Landslides – 1,300 to 2,100 feet from alignment Burns et al., 2011 63.9 63.9 Potential Rapidly Moving Landslide Hofmeister, 2002 64.5 64.6 Landslide Topography CH2M HILL, 2013 65.3 65.4 Landslide Topography CH2M HILL, 2013 65.8 65.9 Landslide Topography CH2M HILL, 2013 66.2 66.3 Landslide Topography CH2M HILL, 2013 66.7 66.7 Potential Gullying/Erosion/Debris Flow CH2M HILL, 2013 67.2 67.3 Landslide Topography CH2M HILL, 2013 67.6 68.0 Landslide Topography, Potential Gullying/Erosion/Debris Flow CH2M HILL, 2013 69.1 69.1 Potential Gullying/Erosion/Debris Flow CH2M HILL, 2013 69.7 69.9 Landslide Topography CH2M HILL, 2013 70.2 70.2 Potential Gullying/Erosion/Debris Flow CH2M HILL, 2013 70.6 71.3 Landslide Topography; Potential Gullying/Erosion/Debris Flow CH2M HILL, 2013 71.6 71.7 Landslide Topography CH2M HILL, 2013 71.8 71.8 Potential Gullying/Erosion/Debris Flow CH2M HILL, 2013 72.1 72.9 Landslide Topography, Potential Gullying/Erosion/Debris Flow CH2M HILL, 2013 73.6 73.6 Potential Gullying/Erosion/Debris Flow CH2M HILL, 2013 73.7 74.2 Landslide Topography, Potential Gullying/Erosion/Debris Flow CH2M HILL, 2013 75.4 75.4 Potential Gullying/Erosion/Debris Flow CH2M HILL, 2013 76.1 76.8 Landslide Topography, Potential Gullying/Erosion/Debris Flow CH2M HILL, 2013 77.9 79.3 Landslide Deposits, Landslide Topography Burns et al., 2011; CH2M HILL85.6 86.0 Mapped Deep-Seated Composite Landslide, Landslide Topography DNR, 2010; CH2M HILL, 2013 86.3 86.4 Mapped Deep-Seated Composite Landslide DNR, 2010; CH2M HILL, 2013 86.6 86.8 Mapped Deep-Seated Rotational Landslide DNR, 2010; CH2M HILL, 2013 
 G2-4 

Appendix G2 

Landslide Hazard Areas Crossed by the Oregon LNG Pipeline 

Mapped Landslide Hazard a

From MP To MP Type of Landslide Hazard Refere

__________ a The milepost numbers in this table identify landslide hazards shown on published landslide hazard mapping and on the project-specific landslide invento

prepared for Oregon LNG. Source documentation is provided in the “References” column of this table. 

b Milepost numbers adjusted for consistency with CH2M HILL, 2013. 

References Beaulieu, J.D. 1973. “Environmental Geology of Inland Tillamook and Clatsop Counties.” Oregon Department of Geology and Mineral Industries. Bulletin 7Burns, W.J., K.A. Mickelson, and E.C Saint-Pierre. 2011. Statewide Landslide Information Database for Oregon (SLIDO) Release 2. Oregon Department o

Industries. Publication SLIDO-2. 

CH2M HILL. 2009. Geologic Hazard: Slope Instability/Landslide Inventory Maps prepared for Resource Report 6. 

CH2M HILL. 2013. Geologic Hazard: Slope Instability/Landslide Inventory Map, Attachment 4A to Resource Report 6. Hofmeister, J.R. 2002. Hazard Map of Potential Rapidly Moving Landslides in Western Oregon. Oregon Department of Geology and Mineral Industries. Pu

Series IMS-22. 

Schlicker, H.G., R.J. Deacon, J.D. Beaulieu, and G.W. Olcott. 1972. Environmental Geology of the Coastal Region of Tillamook and Clatsop Counties, Ore

Geology and Mineral Industries. Bulletin 74. 

Washington State Department of Natural Resources (DNR). 2010. Landslides. Geographic Information Systems data dated June 2010. 

http://www.dnr.wa.gov/ResearchScience/Topics/GeosciencesData/Pages/gis_data. aspx. Scale: 1: 24,000. Last accessed April 1, 2013. 
APPENDIX G3 

SITE-SPECIFIC WATERBODY CROSSING PLANS






























20140811-5160 FERC PDF (Unofficial) 8/11/2014 3:46:27 PM
20140811-5160 FERC PDF (Unofficial) 8/11/2014 3:46:27 PM

APPENDIX G4 

STREAM CHANNEL ASSESSMENT AND SCOUR ANALYSIS

TECHNICAL MEMORANDUM

Channel Response Matrix for Pipeline Crossings of Perennial 

Endangered Species Act Streams

PREPARED FOR: Oregon LNG

PREPARED BY: Greg White/CH2M HILL

Paul Casperson/CH2M HILL

Dana Larson/CH2M HILL

COPIES: Jay Lorenz/CH2M HILL

DATE: May 16, 2013

Introduction

This technical memorandum presents the results of a high-level stream channel assessment and scour analysis for 

the waterbodies crossed by the Oregon Pipeline. Oregon LNG proposes to construct and operate the Oregon 

Pipeline and associated LNG terminal. The Oregon Pipeline consists of approximately 86.8 miles of 36-inchdiameter pipeline to be constructed between Warrenton, Oregon, and Woodland, Washington, crossing three 

counties, Clatsop, Columbia, and Cowlitz. The pipeline will cross numerous intermittent and perennial streams 

and rivers. Specific scour analyses and migration studies may be performed at a later date for specific crossings as 

required by Oregon LNG and/or permitting agencies.

This stream channel assessment combines an evaluation of channel morphology and channel-forming processes 

to simplify a wide variety of channels into a manageable analysis framework. Channel segments (subreach units) 

are areas of streams that respond to disturbances in a similar fashion based on similarities in channel-forming 

processes. The assessment of channel conditions provides a context for evaluating the influence of changes in 

land management or activities on channel conditions and processes. Major changes in channel morphology 

(scour) are caused by changes in discharge, sediment supply, and vegetation in the channel. The scour analysis 

focuses on fluvial-dominated stream channels and provides a first-cut method of identifying stream crossings with 

a potential for vertical and/or lateral scouring (i.e., lateral channel migration). 

Methods

Streams with perennial flow regimes and supporting Federal Endangered Species Act (ESA)-listed salmonids were 

evaluated to determine which pipeline crossings have a predisposition for vertical scouring or lateral migration. A 

total of 120 streams crossed by the Oregon Pipeline have perennial flow regimes, support ESA-listed salmonids, or 

have designated critical habitat. Twenty-four of those streams support ESA-listed salmonids or have designated 

critical habitat. Although some intermittent and ephemeral drainages not supporting ESA-listed salmonids will 

require further investigation prior to final engineering design, these sites were not included at this time for this 

study.

Stream segment slope (gradient) and channel confinement provide a useful orientation for stream classification 

and provide a method to distinguish between the possible responses of a stream channel to disturbances. 

Channel confinement is the ratio of the valley or floodplain width to the channel width.

Stream slope at potential pipeline crossings was determined from field reconnaissance surveys. Where field 

reconnaissance surveys were not conducted, channel gradient was determined from 1:24,000 U.S. Geological 

Survey (USGS) topographic maps by measuring the distance between a contour line upstream and a contour line 

downstream of the crossing, or by using Washington 10-meter Digital Elevation Model (DEM) elevations. Channel 

confinement was determined by measuring the valley width or floodplain (distance between contour lines on 

either side of the channel at the crossing based on a 1:24,000 USGS topographic map) and comparing this width 

to the channel width (ordinary high water [OHW] width).

ES030613113935PDX 1
CHANNEL RESPONSE MATRIX FOR PIPELINE CROSSINGS OF PERENNIAL ENDANGERED SPECIES ACT STREAMS

After determining channel gradient, channel confinement, and valley width at Pipeline crossings, streams were 

grouped into categories based on their similarities and channel characteristics. Streams with specific similarities 

are expected to have similar responses to disturbances or be predisposed to specific conditions. These responses 

or conditions are based in part on the Washington Department of Natural Resources (DNR) Watershed 

Assessment Methodology (1994) Channel Response Matrix. This approach is also consistent with previous pipeline 

projects in the area that have included multiple waterbody crossings. In addition, the Rosgen channel type 

(Rosgen, 1996), which was identified by channel characteristics collected during field reconnaissance surveys, was 

used to verify and support DNR Channel Response Matrix characteristics.

Ephemeral drainages (defined as streams with flows generated by periodic surface runoff along the Pipeline route 

were not analyzed for scour events. Ephemeral drainages, as defined in the assessment method, only flow during 

and shortly after a large precipitation event and lack the hydrological and morphological characteristics of a 

perennial or intermittent stream. Ephemeral drainages may not have a well-defined channel and may be 

vegetated. Therefore, ephemeral drainages are not considered to have vertical or lateral scour potential. 

However, ephemeral drainages could experience mass wasting events, such as landslides or slope failure, which 

could affect the pipeline. Landslide and slope failure potential along the Pipeline are further evaluated in Resource 

Report 6 — Geologic Resources.

In addition to ephemeral drainages, non-ESA intermittent streams were also excluded as they are primarily minor 

waterways with generally lower scour risk. However, as discussed above, they may still experience mass wasting 

events that could affect the pipeline.

According to Rosgen (1996) and personal communication with Janine Castro of the U.S. Fish and Wildlife Service 

(Castro, 2009), only streams with a gradient of less than 4 percent typically have the potential for significant 

lateral scouring at the reach level. Streams with a greater than 4 percent gradient have no functional floodplain 

and therefore have no, or little, potential for lateral channel migration at the reach scale.

At ESA stream crossings and within Federal Emergency Management Agency floodways, the pipeline will be 

buried at a depth that minimizes the risk of exposure from vertical scour and channel migration. The actual depth 

of the pipeline will be determined during final engineering to address risks of vertical scour and channel 

migration.

Results

Stream channels with similar characteristics are expected to respond to disturbances similarly or be predisposed 

to specific events. Channel slope can be used as a surrogate for stream energy, which is the dominant aspect 

controlling channel morphology. Channel confinement controls the characteristics of potential channel responses 

and manifests the long-term history of a valley (DNR, 1994). Increased entrenchment is one possible channel 

response to disturbance. Entrenchment is defined as the vertical containment and the degree to which a channel 

is incised in the valley floor (DNR, 1994).

Channel slope and confinement are general indicators of a stream’s transport capacity and the balance between 

sediment supply and transport capacity (DNR, 1994). The Channel Response Matrix provides a simple method for 

categorizing potential channel responses in terms of gradient and channel confinement and is based on 

geomorphic reasoning and professional experience. The matrix differentiates between fluvial and mass-wasting 

dominated channels. Twenty percent channel slope typically defines the upper limit of fluvially dominated 

channel systems (DNR, 1994).

The DNR Channel Response Matrix shows a channel’s predisposition to specific events given specific channel 

characteristics. These characteristics are based on channel slope, channel confinement, and valley width. The 

potential channel responses based on these characteristics include fine sediment deposition, bank erosion, wood 

loss, debris flow scour, and debris flow deposition. Channel reaches can be grouped into source, transport, and 

response reaches using gradient as the criterion. Reaches greater than 20 percent gradient are considered source 

reaches, 3 to 20 percent gradient are transport reaches, and less than 3 percent gradient are response reaches. 

ES030613113935PDX 2
CHANNEL RESPONSE MATRIX FOR PIPELINE CROSSINGS OF PERENNIAL ENDANGERED SPECIES ACT STREAMS

Six gradient groupings are used to generally correspond to gradients associated with changes in channel 

morphology that reflect relative transport capacity and the response potential (DNR, 1994).

The 24 streams evaluated using this methodology were categorized into six distinct groups based on slope, 

channel width, and confinement (Table 1). Table 2 (located at the end of this technical memorandum) provides 

specific stream crossing ID numbers, stream slope (gradient %), valley width, confinement, and vertical and/or 

lateral scour potential for each of the 24 ESA perennial streams.

TABLE 1

Channel Response Matrix for Pipeline Crossings of Perennial Waterbodies and Streams Supporting ESA-listed Salmonids

Channel Type

Scour Potential of Evaluated Stream Crossings (Vertical/Lateral)

None

(at Reach 

Scale)/Slight Slight/Moderate Moderate/Severe

Moderate to 

Severe/None Severe/None

Severe (Mass 

Wasting 

Dominated)/None

Valley Width (VW) > 4 Channel 

Width (CW) (Unconfined)

11 3 7 1

2 CW < VW < 4 CW 

(Moderately Confined)

1

VW < 2 CW (Confined) 1

Gradient and Typical Channel Bed Morphology

Channel Gradient Percentage 

(Stream Type)

< 1

(Pool-Riffle)

1 to 2

(Pool-Riffle, 

Plane-Bed)

2 to 4

(Plane-Bed, 

Forced Pool-Riffle)

4 to 8

(Step-Pool)

8 to 20

(Cascade)

> 20

(Colluvial)

Source: DNR, 1994.

Notes: Valley width (VW) = distance between first contour lines on either side of channel (1:24,000 scale USGS). Channel width (CW) = OHW 

channel width.

Based on DNR (1994) Standard Watershed Analysis Methodology, six channel types with the potential for either 

lateral (bank erosion causing channel migration) and/or vertical (debris flow) scour potential were identified for 

streams being crossed by the pipeline. Of the 24 perennial/ ESA stream crossings, 11 possess some potential for 

vertical scouring or debris flow events, while 23 have at least some potential for lateral channel migration.

Unconfined channels with slopes less than 1 percent (11 streams) are associated with:

• Fine sediment deposition

• Bank erosion

• Wood accumulation

Unconfined channels with slopes between 1 and 2 percent (3 streams) are associated with:

• Wood loss

• Scour potential

• Fine sediment deposition

• Bank erosion

Unconfined channels with slopes between 2 and 4 percent (7 streams) are associated with:

• Dam break flood

• Debris flow deposition

• Bank erosion

• Coarse sediment deposition

• Scour potential

• Wood loss

ES030613113935PDX 3
CHANNEL RESPONSE MATRIX FOR PIPELINE CROSSINGS OF PERENNIAL ENDANGERED SPECIES ACT STREAMS

Unconfined channels with slopes between 4 and 8 percent (1 stream) are associated with:

• Debris flow scour/debris flow deposition

• Dam break flood

• Wood loss

Moderately confined channels with slopes less than 1 percent (1 stream) are associated with:

• Fine sediment deposition

• Bank erosion

• Wood accumulation

Confined channels with slopes less than 1 percent (1 stream) are associated with:

• Coarse sediment deposition

• Wood loss

Ten of the evaluated waterways will be crossed via horizontal directional drilling (HDD). Of these 10 crossings, one

(Bear Creek) has more than a slight vertical scour potential. Of the remaining nine HDD crossings, all have no 

vertical scour potential and have a slight lateral scour potential. The remaining crossing has a severe lateral scour 

potential (Bear Creek). 

This high-level method of scour potential determination relies exclusively on gradient, valley width, and channel 

width, excluding additional factors such as substrate type. For certain waterways, historical observation and 

empirical evidence suggest that the scour potential may be different than that estimated by this model. In these 

cases, engineering will determine the accurate depth for the pipe crossing.

Conclusions

Of the 24 perennial ESA streams being crossed by the pipeline, 11 have a slight or higher potential for vertical 

scouring. Of these, eight have a moderate or higher potential for vertical scouring. One channel has a severe 

potential for vertical scouring, and eight channels are mass-wasting dominated (MWD). The only stream with 

moderate/severe vertical scour potential is an intermediate waterway. Seven of the MWD streams are classified 

as intermediate, with the one remaining classified as minor. Thirteen streams have no vertical scour potential. Of 

the streams evaluated, five are considered major streams (100 feet or greater in width as defined by the Federal 

Energy Regulatory Commission’s Wetland and Waterbody Construction and Mitigation Procedures [2003]), none 

of which have a slight or higher potential for experiencing vertical scouring flows (no vertical scour potential).

One crossing (Little Clatskanie River) has no or negligible potential for lateral channel migration (lateral scouring) 

at the reach scale, 13 have a slight potential, 3 have a moderate potential, and 7 have a severe potential for 

lateral channel migration. Of the seven streams with a severe potential for lateral scour, all are intermediate 

waterbodies. The five major stream crossings have a slight potential for lateral channel migration. Potential for 

vertical scour and channel migration will be used to inform engineers which streams require special attention 

regarding depth of pipeline during final design.

Literature Cited

Castro, J.M. 2009. Personal communications with Janine Castro, Ph.D. Geomorphologist, U.S. Fish and Wildlife 

Service, Portland, Oregon. April 9, 2009.

Federal Energy Regulatory Commission. 2003. Wetland and Waterbody Construction and Mitigation Procedures. 

http://www.ferc.gov/industries/gas/enviro/guidelines.asp. January 17, 2003.

Rosgen, D. 1996. Applied River Morphology. Wildland Hydrology, Pagosa Springs, Colorado.

Washington Department of Natural Resources (DNR). 1994. Board Manual: Standard Methodology for Conducting 

Watershed Analysis Under Chapter 222-22 WAC. Washington Department of Natural Resources, Olympia, 

Washington.

ES030613113935PDX 4
CHANNEL RESPONSE MATRIX FOR PIPELINE CROSSINGS OF PERENNIAL ENDANGERED SPECIES ACT STREAMS

TABLE 2

Oregon Pipeline Crossings of Perennial ESA Streams

Stream ID

MP at 

Crossing

Crossing 

Method Flow Regime

Waterbody 

Type Waterbody

Valley 

Width 

(ft)a

OHW 

Width 

(ft) Channel Confinementb

Gradient 

(%)c

Vertical Scour 

Potentiald

Lateral Channel 

Migration 

Potentiale

S99CL001 1.0 HDD Perennial Major Adairs Slough 5,258 110 Unconfined <1 None Slight

S5BCLo74 1.5 HDD Perennial Intermediate Vera Creek 4,960 20 Unconfined <1 None Slight

S40CL002 3.1 HDD Perennial Major Lewis and Clark River 5,808 1250 Unconfined <1 None Slight

S5BCL064 4.5 Dry/Flume Perennial Intermediate Barrett Slough 3,844 12 Unconfined <1 None Slight

S99CL064 5.7 HDD Perennial Major Lewis and Clark River 2,261 340 Unconfined <1 None Slight

S1BCL001 7.9 Dry/Flume Perennial Intermediate Heckard Creek 1,139 10 Unconfined <1 None Slight

S99CL018 11.0 HDD Perennial Intermediate Lewis and Clark River 1,365 35 Unconfined <1 None Slight

S2BCL008A 25.4 Dry/Flume Perennial Intermediate Little Fishhawk Creek 104 15 Unconfined <1 None Slight

S2BCL008B 31.4 Open cut Perennial Intermediate Alder Creek 421 15 Unconfined 3.6 Moderate Severe

S99CL108 33.5 HDD Perennial Major Nehalem River 3,601 120 Moderately Confined <1 None Slight

S8BCL005 41.0 Open cut Perennial Intermediate Rock Creek 470 20 Unconfined 2.2 Moderate Severe

S1BCL021 43.1 Dry/Flume Perennial Intermediate South fork Rock Creek 2,302 15 Unconfined 3.0 Moderate Severe

S1BCL022 43.4 HDD Perennial Intermediate Bear Creek 436 12 Unconfined 2.3 Moderate Severe

S6BCO002 47.5 Dry/Flume Perennial Intermediate North Fork Wolf Creek 143 30 Unconfined 1.0 Slight Moderate

S3BCO012 50.5 Dry/Flume Perennial Intermediate Clear Creek 780 30 Unconfined 2.1 Moderate Severe

S3BCO107 55.7 Dry/Flume Perennial Intermediate Cedar Creek 976 10 Unconfined 1.6 Slight Moderate

S3BCO101 57.7 HDD Perennial Intermediate Rock Creek 1,157 30 Unconfined <1 None Slight

S3BCO014 63.8 HDD Perennial Intermediate Nehalem River 113 30 Moderately Confined <1 None Slight

S99CO020 70.7 Open cut Perennial Intermediate Clatskanie River 219 19 Unconfined <1 None Slight

S5BCO001 71.8 Open cut Perennial Minor Little Clatskanie River 244 2 Unconfined 4 Moderate/Severe None

S3BCO010 73.0 Open cut Perennial Intermediate Milton Creek 317 12 Unconfined 3.2 Moderate Severe

S3BCO018 76.4 Open cut Perennial Minor Merril Creek 376 1 Unconfined 1.1 Slight Moderate

S99CO011 81.6 Open cut Perennial Intermediate Deer Island Slough 780 38 Unconfined 2.1 Moderate Severe

S99BCO014 82.4 HDD Perennial Major Columbia River 5,637 3300 Confined <1 None Slight

a Valley width (VW) = distance between first contour lines on either side of channel (1:24,000 scale U.S. Geological Survey).

b Channel confinement based on Channel Response Matrix (Table E-2) in DNR (1994):

VW > 4CW = Unconfined

2CW < VW < 4CW = Moderately Confined

VW < 2CW = Confined

c Where gradient not field collected, used 1:24,000 USGS topographic maps. Gradient listed as 0.0% means gradient < 1%.

d For vertical scour potential, “None” means on a reach scale. There will still likely be pool scour etc.

e Lateral channel migration potential based on DNR (1994):

ES030613113935PDX 5
CHANNEL RESPONSE MATRIX FOR PIPELINE CROSSINGS OF PERENNIAL ENDANGERED SPECIES ACT STREAMS

TABLE 2

Oregon Pipeline Crossings of Perennial ESA Streams

Stream ID

MP at 

Crossing

Crossing 

Method Flow Regime

Waterbody 

Type Waterbody

Valley 

Width 

(ft)a

OHW 

Width 

(ft) Channel Confinementb

Gradient 

(%)c

Vertical Scour 

Potentiald

Lateral Channel 

Migration 

Potentiale

None = Could be microbank erosion but not lateral channel migration.

Slight = Unconfined or moderately confined channel with gradient < 1%.

Moderate = Unconfined or moderately confined channel with gradient 1% - 2%.

Severe = Unconfined or moderately confined channel with gradient 2% - 4%.

Stream ID = stream identification number

ft = feet 

MP = milepost

ES030613113935PDX 6
APPENDIX G5 

RIPARIAN AREAS CROSSED BY THE OREGON LNG PIPELINE

G5-1 

Appendix G5 

Riparian Areas Crossed by the Oregon LNG Pipeline

Milepost Stream ID a

Stream Width b Waterbody c Crossing Method d Stream Type 

Miles to 

Salmonid 

Habitat 

ODFW 

Stream 

Type ODFW Habitat Type e

R

1 S99CL001 110 Adairs Slough HDD Perennial 0.00 2 PEM2, PSS2, ST2 88 

1.5 S5BCL074 20 Vera Creek Flume Perennial 0.49 2 PEM2, PEM3, PSS2, PSS3, 

ST2 

18 

2.6 S40CL001 50 Tributary of Lewis 

and Clark River 

Open Cut Intermittent 0.47 3 PSS2, ST3 87 

3.1 S40CL002 1250 Lewis and Clark 

River 

HDD Perennial 0.00 2 ST2 

3.5 S99CL019 13 Tributary of Jeffers 

Slough 

Flume Perennial 0.23 3 PEM5, ST3 

4.1 S5BCL059 1.5 Tributary of Barrett 

Slough 

Flume Perennial 0.10 3 PEM5, ST3 

4.2 S5BCL062 2 Tributary of Barrett 

Slough 

Open Cut Intermittent 0.12 3 PEM5, ST3 

4.3 S5BCL063 4.5 Tributary of Barrett 

Slough 

Open Cut Intermittent 0.06 3 PEM5, ST3 

4.5 S5BCL064 12 Barrett Slough Flume Perennial 0.00 2 DF4, PEM2, PEM5, PFO2, 

ST2 

5 D

4.6 S5BCL066 3 Tributary of Barrett 

Slough 

Open Cut Intermittent 0.11 3 BP6, PEM2, PEM5, ST3 

4.8 S5BCL068 8 Tributary of Green 

Slough 

Open Cut Intermittent 0.30 3 PEM3, PEM5, ST3 

4.8 S5BCL069 7 Tributary of Green 

Slough 

Open Cut Intermittent 0.40 3 PEM3, PEM5, ST3 

4.9 SBCL070 2 Unnamed Open Cut Intermittent 0.20 2 AW5, DF4, ST2 4 D5 S5BCL071 5 Unnamed HDD Intermittent 0.54 3 DF4, PEM5, PFO2, ST3 11 

5.2 S5BCL072 7 Tributary of Lewis 

and Clark River 

HDD Perennial 0.09 2 DF4, PEM2, PEM5, PFO2, 

PSS2, ST2 

55 PSS

5.2 S99CL111 300 Lewis and Clark 

River 

HDD Perennial 0.00 2 BP5, DF4, PEM2, PEM5, 

PSS2, ST2 

31 

5.4 S99CL034 20 Tributary of Lewis 

and Clark River 

HDD Perennial 0.08 2 BP5, PEM2, PEM5, ST2 

5.5 S99CL024 13 Tributary of Lewis 

and Clark River 

Open Cut Intermittent 0.10 2 PEM5, ST2 

5.7 S99CL064 340 Lewis and Clark 

River 

HDD Perennial 0.00 2 NO4, PEM2, PEM3, PEM5, 

ST2 

 

5.8 S38CL003 8 Tributary of Lewis 

and Clark River 

HDD Intermittent 0.41 3 PEM2, PEM3, PEM5, 

PSS2, ST3 

11 
G5-2 

Appendix G5 

Riparian Areas Crossed by the Oregon LNG Pipeline

Milepost Stream ID a

Stream Width b Waterbody c Crossing Method d Stream Type 

Miles to 

Salmonid 

Habitat 

ODFW 

Stream 

Type ODFW Habitat Type e

R

7.9 S1BCL001 10 Heckard Creek Flume Perennial 0.02 2 CF4, PEM2, PEM3, PFO2, 

ST2 

72 C

8.1 S1BCL050 10 Unnamed Open Cut Intermittent 0.13 3 CF4, CF5, PEM3 68 C

PEM

8.6 S1BCL002 4 Tributary of Lewis 

and Clark River 

Open Cut Intermittent 1.17 2 CF4, ST2 99 C

8.8 S1BCL018 25 Tributary of Lewis 

and Clark River 

Flume Perennial 1.29 2 CF4, PEM2, ST2 95 C

9.1 S1BCL003 3 Tributary of Lewis 

and Clark River 

Open Cut Intermittent 0.86 2 CF4, ST2 99 C

9.3 S1BCL004 4 Tributary of Lewis 

and Clark River 

Open Cut Intermittent 0.82 3 CF5, ST3 99 C

9.7 S1BCL005 8 Tributary of Lewis 

and Clark River 

Open Cut Intermittent 0.97 2 CF4, CF5, ST2 88 C

9.7 S1BCL006 3 Tributary of Lewis 

and Clark River 

Open Cut Intermittent 0.96 2 CF4, ST2 99 C

9.9 S1BCL007 3 Tributary of Lewis 

and Clark River 

Open Cut Intermittent 0.97 2 CF4, ST2 99 C

10 S1BCL008 10 Tributary of Lewis 

and Clark River 

Flume Perennial 0.98 2 CF4, ST2 99 C

11 S99CL018 35 Lewis and Clark 

River 

HDD Perennial 0.00 2 BP6, CF3, NO5, PEM2, 

PEM5, PFO2, ST2 

6 C

12.8 S1BCL016 8 Tributary of Speelyai 

Creek 

Flume Perennial 1.03 2 CF4, ST2 99 C

13.8 S5BCL040 0.8 Tributary of Youngs 

River 

Flume Perennial 2.02 2 BP5, CF4, ST2 99 C

13.8 S5BCL041 2 Tributary of Youngs 

River 

Flume Perennial 2.03 2 BP5, CF4, ST2 99 C

13.9 S5BCL042 5 Tributary of Youngs 

River 

Open Cut Intermittent 2.05 2 CF4, ST2 98 C

13.9 S5BCL043 20 Tributary of Youngs 

River 

Open Cut Intermittent 2.08 2 CF4, ST2 95 C

14.1 S5BCL045 8 Tributary of Youngs 

River 

Flume Perennial 2.15 2 CF4, ST2 99 C

14.2 S5BCL044 5 Tributary of Youngs 

River 

Flume Perennial 2.16 2 CF4, ST2 99 C

14.8 S5BCL038 2 Tributary of Youngs 

River 

Open Cut Intermittent 2.28 2 CF4, DF4, ST2 84 C
G5-3 

Appendix G5 

Riparian Areas Crossed by the Oregon LNG Pipeline

Milepost Stream ID a

Stream Width b Waterbody c Crossing Method d Stream Type 

Miles to 

Salmonid 

Habitat 

ODFW 

Stream 

Type ODFW Habitat Type e

R

15.3 S5BCL035 3 Tributary of Youngs 

River 

Open Cut Intermittent 2.09 2 CF4, CF5, ST2 0 C

15.6 S5BCL030 4 Tributary of Youngs 

River 

Flume Perennial 2.11 2 CF4, CF5, ST2 77 C

15.6 S5BCL034 4 Tributary of Youngs 

River 

Flume Perennial 2.08 2 CF4, CF5, ST2 58 C

15.8 S5BCL031 5 Tributary of Youngs 

River 

Flume Perennial 2.25 2 CF4, DF3, DF4, PEM2, 

PEM3, ST2 

11 CDF4 

16.1 S99CL016 7 Bayney Creek Flume Perennial 2.49 3 DF3, ST3 99 16.6 S5BCL032 3 Tributary of Youngs 

River 

Open Cut Intermittent 2.98 2 CF4, DF3, PEM3, ST2 96 C

17.3 S5BCL077 6 Tributary of Youngs 

River 

Flume Perennial 3.61 2 CF4, ST2 99 C

17.8 S5BCL078 6 Tributary of Youngs 

River 

Open Cut Intermittent 4.05 2 DF3, PEM2, ST2 95 

17.8 S5BCL079 5 Tributary of Youngs 

River 

Open Cut Intermittent 4.09 2 DF3, PEM2, ST2 90 

17.9 S5BCL080 4 Tributary of Youngs 

River 

Open Cut Intermittent 4.20 2 DF3, ST2 99 

18.4 S5BCL076 4 Tributary of Rock 

Creek 

Flume Perennial 4.64 3 CF4, DF4, PEM2, ST3 78 C

18.5 S1BCL009 10 Rock Creek Flume Perennial 4.78 3 CF4, DF3, DF4, PFO2, ST2, 

ST3 

15 CDF4

18.8 S1BCL010 5 Tributary of Youngs 

River 

Open Cut Intermittent 5.08 2 CF4, DF3, ST2 82 C

19 S1BCL011 6 Tributary of Youngs 

River 

Flume Perennial 5.25 2 DF3, PEM3, PFO2, PFO3, 

ST2 

97 PFO

19.14 S1BCO012 3 Unnamed Open Cut Intermittent 2.93 2 DF3, ST2 99 19.3 S1BCL014 8 Osgood Creek Flume Perennial 5.55 3 CF3, CF4, CF5, DF3, 

PEM2, PEM3, PFO2, ST3 

30 CCF5

19.6 S2BCL013A 7 Tributary of Osgood 

Creek 

Flume Perennial 5.79 3 CF3, CF4, PEM3, PFO2, 

ST3 

13 CPFO

20.1 S2BCL013B 35 Fox Creek Flume Perennial 6.10 3 CF4, DF3, ST3 71 C21.4 S38CL013 3 South Fork Youngs 

River 

Flume Perennial 7.16 2 CF4, DF3, ST2 71 C

21.6 S42CL003 3 Unnamed Open Cut Intermittent 2.83 2 CF4, DF3, ST2 81 C21.8 S5BCL058 15 Tributary of Youngs 

River 

Flume Perennial 7.58 2 CF3, CF4, ST2 16 C
G5-4 

Appendix G5 

Riparian Areas Crossed by the Oregon LNG Pipeline

Milepost Stream ID a

Stream Width b Waterbody c Crossing Method d Stream Type 

Miles to 

Salmonid 

Habitat 

ODFW 

Stream 

Type ODFW Habitat Type e

R

22.1 S5BCL049 2.5 Tributary of Youngs 

River 

Flume Perennial 7.85 3 CF4, DF3, PEM2, ST2, ST3 95 C

22.2 S5BCL048 5 Tributary of Youngs 

River 

Open Cut Intermittent 7.92 3 CF4, DF3, ST3 98 C

22.5 S6BCL016 2 Tributary of Youngs 

River 

Open Cut Intermittent 8.20 2 CF4, DF3, PEM2, PFO2, 

ST2 

20 CPFO

22.6 S6BCL013 1 Tributary of Youngs 

River 

Open Cut Intermittent 8.28 2 CF4, DF3, PEM2, ST2 88 C

22.6 S6BCL014 4 Tributary of Youngs 

River 

Open Cut Intermittent 8.29 2 CF4, DF3, ST2 96 C

22.6 S6BCL015 2 Tributary of Youngs 

River 

Open Cut Intermittent 8.23 2 CF4, DF3, PEM2, PFO2, 

ST2 

36 CPFO

22.8 S6BCL010 2 Tributary of Youngs 

River 

Open Cut Intermittent 8.49 2 CF4, ST2 98 C

22.8 S6BCL011 2 Tributary of Youngs 

River 

Open Cut Intermittent 8.45 2 CF4, ST2 99 C

22.8 S6BCL017 3.5 Tributary of Youngs 

River 

Open Cut Intermittent 8.51 2 CF4, ST2 99 C

22.9 S6BCL018 4 Tributary of Fall 

Creek 

Open Cut Intermittent 8.62 3 CF4, ST3 99 C

23 S6BCL019 20 Tributary of Fall 

Creek 

Flume Perennial 8.66 3 CF3, CF4, ST3 54 C

23.1 S6BCL020 3 Tributary of Fall 

Creek 

Open Cut Intermittent 8.77 3 CF3, ST3 99 C

23.4 S38CL014 10 Fall Creek Flume Perennial 9.11 3 CF3, CF4, DF3, ST3 40 C

DF3 

24.3 S5BCL016 3.5 Tributary of 

Fishhawk Creek 

Open Cut Intermittent 2.36 3 CF4, ST3 99 C

24.4 S5BCL017 3.5 Tributary of 

Fishhawk Creek 

Open Cut Intermittent 2.34 3 CF4, PEM2, ST3 94 C

24.4 S5BCL018 6 Tributary of 

Fishhawk Creek 

Flume Perennial 2.32 3 CF4, PEM2, ST3 98 C

24.8 S2BCL001 7 Tributary of 

Fishhawk Creek 

Open Cut Intermittent 2.09 3 CF4, PSS2, ST3 82 C

24.8 S2BCL002 25 Tributary of 

Fishhawk Creek 

Open Cut Intermittent 2.08 3 CF4, PSS2, ST3 84 C

25.1 S2BCL003 8 Tributary of 

Fishhawk Creek 

Open Cut Intermittent 1.97 3 CF4, ST3 97 C
G5-5 

Appendix G5 

Riparian Areas Crossed by the Oregon LNG Pipeline

Milepost Stream ID a

Stream Width b Waterbody c Crossing Method d Stream Type 

Miles to 

Salmonid 

Habitat 

ODFW 

Stream 

Type ODFW Habitat Type e

R

25.2 S2BCL004 3 Tributary of 

Fishhawk Creek 

Open Cut Intermittent 1.96 3 CF4, ST3 96 C

25.2 S2BCL005 10 Tributary of 

Fishhawk Creek 

Flume Perennial 1.96 3 CF4, PEM2, ST3 97 C

25.3 S2BCL007 3 Tributary of 

Fishhawk Creek 

Flume Perennial 1.95 3 CF3, CF4, PEM2, ST3 10 C

PEM

25.4 S2BCL008A 15 Tributary of 

Fishhawk Creek 

Flume Perennial 1.95 3 CF3, CF4, PEM2, ST3 10 C

PEM

25.7 S2BCL009 10 Tributary of Little 

Fishhawk Creek 

Flume Perennial 4.29 3 CF4, DF3, ST3 80 C

25.7 S2BCL010 4 Tributary of Little 

Fishhawk Creek 

Open Cut Intermittent 4.27 3 CF4, ST3 98 C

25.9 S2BCL012 10 Tributary of Little 

Fishhawk Creek 

Open Cut Intermittent 4.19 3 CF4, PEM2, ST3 94 C

26.3 S5BCL019 1.2 Tributary of Little 

Fishhawk Creek 

Flume Perennial 3.87 2 CF4, ST2 100 

26.5 S5BCL029 1.5 Tributary of Little 

Fishhawk Creek 

Flume Perennial 3.68 2 CF4, ST2 99 C

26.6 S5BCL027 1 Tributary of Little 

Fishhawk Creek 

Flume Perennial 3.63 2 CF4, ST2 99 C

26.6 S5BCL028 2 Tributary of Little 

Fishhawk Creek 

Open Cut Intermittent 3.63 2 CF4, ST2 99 C

26.8 S5BCL023 1.3 Tributary of Little 

Fishhawk Creek 

Flume Perennial 3.40 3 CF3, CF4, PEM2, ST3 61 C

26.8 S5BCL025 1.4 Tributary of Little 

Fishhawk Creek 

Flume Perennial 3.41 3 CF3, CF4, PEM2, ST3 48 C

27 S5BCL022 3 Tributary of Little 

Fishhawk Creek 

Open Cut Intermittent 3.27 3 CF3, CF4, ST3 50 C

27.2 S5BCL021 6 Tributary of Little 

Fishhawk Creek 

Flume Perennial 3.05 3 CF3, CF4, PEM2, ST3 19 C

27.3 S5BCL020 1.8 Tributary of Little 

Fishhawk Creek 

Flume Perennial 2.97 3 CF3, CF4, CF5, PEM2, ST3 18 C

CF5 

27.4 S5BCL015 4 Tributary of Little 

Fishhawk Creek 

Flume Perennial 2.89 3 CF4, CF5, ST3 99 C

27.6 S5BCL014 2.4 Tributary of Little 

Fishhawk Creek 

Open Cut Intermittent 2.68 3 CF4, ST3 99 C

27.8 S5BCL012 2 Tributary of Little 

Fishhawk Creek 

Open Cut Intermittent 2.55 3 CF3, CF4, ST3 11 C
G5-6 

Appendix G5 

Riparian Areas Crossed by the Oregon LNG Pipeline

Milepost Stream ID a

Stream Width b Waterbody c Crossing Method d Stream Type 

Miles to 

Salmonid 

Habitat 

ODFW 

Stream 

Type ODFW Habitat Type e

R

27.8 S5BCL013 2 Tributary of Little 

Fishhawk Creek 

Open Cut Intermittent 2.56 3 CF3, CF4, ST3 12 C

27.9 S5BCL011 3 Tributary of Little 

Fishhawk Creek 

Open Cut Intermittent 2.46 3 CF4, CF5, ST3 49 C

28.1 S5BCL010 3.5 Tributary of Little 

Fishhawk Creek 

Flume Perennial 2.35 3 CF4, CF5, ST3 4 C

28.4 S5BCL007 6 Tributary of East 

Humbug Creek 

Open Cut Intermittent 1.24 3 CF4, ST3 98 C

28.5 S5BCL004 7 Tributary of East 

Humbug Creek 

Open Cut Intermittent 1.13 3 CF4, ST3 98 C

28.5 S5BCL005 4 Tributary of East 

Humbug Creek 

Open Cut Intermittent 1.19 3 CF4, ST3 99 C

29 S5BCL001 3 Tributary of East 

Humbug Creek 

Open Cut Intermittent 0.79 3 CF4, ST3 97 C

29 S5BCL002 2 Tributary of East 

Humbug Creek 

Open Cut Intermittent 0.81 3 CF4, DF3, ST3 73 C

29.4 S6BCL007 1 Tributary of East 

Humbug Creek 

Open Cut Intermittent 0.81 3 CF3, CF4, ST3 2 C

29.4 S6BCL008 1.5 Tributary of East 

Humbug Creek 

Open Cut Intermittent 0.80 3 CF3, CF4, ST3 1 C

29.5 S6BCL005 6 Tributary of East 

Humbug Creek 

Flume Perennial 0.78 3 CF4, ST3 98 C

29.5 S6BCL006 7 Tributary of East 

Humbug Creek 

Flume Perennial 0.79 3 CF3, CF4, ST3 1 C

29.9 S6BCL004 5 Tributary of East 

Humbug Creek 

Open Cut Intermittent 0.59 3 CF3, CF4, ST3 15 C

30.9 S2BCL021 2 Tributary of East 

Humbug Creek 

Open Cut Intermittent 0.72 3 CF4, ST3 99 C

31.4 S2BCL008B 15 Alder Creek Flume Perennial 0.00 2 CF3, CF4, PEM2, PEM3, 

ST2 

32 C

31.6 S6BCL001 3.5 Tributary of Alder 

Creek 

Open Cut Intermittent 0.21 2 CF4, ST2 99 C

32 S3BCL001 6 Tributary of 

Nehalem River 

Open Cut Intermittent 0.69 2 CF3, CF4, ST2 3 C

32 S3BCL002 6 Tributary of 

Nehalem River 

Open Cut Intermittent 0.68 3 CF3, CF4, ST2, ST3 24 C

32.1 S3BCL003 4 Tributary of 

Nehalem River 

Open Cut Intermittent 0.67 3 CF3, CF4, ST2, ST3 25 C
G5-7 

Appendix G5 

Riparian Areas Crossed by the Oregon LNG Pipeline

Milepost Stream ID a

Stream Width b Waterbody c Crossing Method d Stream Type 

Miles to 

Salmonid 

Habitat 

ODFW 

Stream 

Type ODFW Habitat Type e

R

32.1 S3BCL004 6 Tributary of 

Nehalem River 

Open Cut Intermittent 0.66 2 CF4, ST2 98 C

32.3 S3BCL005 8 Tributary of 

Nehalem River 

Open Cut Intermittent 0.67 3 CF3, CF4, ST3 68 C

32.3 S3BCL006 10 Tributary of 

Nehalem River 

Open Cut Intermittent 0.67 3 CF3, CF4, ST3 74 C

32.4 S3BCL007 8 Tributary of 

Nehalem River 

Open Cut Intermittent 0.68 3 CF3, CF4, ST3 83 C

33.5 S99CL108 120 Nehalem River HDD Perennial 0.00 2 BP4, BP5, BP6, CF3, DF3, 

ST2 

32 C

34.4 S5BCL046 2 Tributary of 

Nehalem River 

Flume Perennial 1.06 2 CF4, PEM3, ST2 99 C

36.2 S3BCL101 10 Unnamed Flume Perennial 0.26 3 CF4, ST2, ST3 92 C36.3 S3BCL102 5 Unnamed Flume Perennial 0.27 3 CF4, ST2, ST3 93 C37.5 S8BCL004 5 Tributary of North 

Fork Quartz Creek 

Flume Perennial 0.47 3 CF3, CF4, PEM3, ST2, ST3 66 C

37.7 S8BCL003 2.3 Tributary of North 

Fork Quartz Creek 

Open Cut Intermittent 0.54 3 CF4, PEM3, ST3 35 C

38.5 S8BCL001 2 Tributary of South 

Form Quartz Creek 

Flume Perennial 1.28 3 CF3, CF4, PSS3, ST2, ST3 7 C

PSS

39.6 S1BCL029 2.6 Tributary of Military 

Creek 

Open Cut Intermittent 0.28 3 CF3, CF4, PFO2, ST3 23 C

PFO

39.8 S1BCL027 1.5 Tributary of Military 

Creek 

Open Cut Intermittent 0.17 3 BP4, CF3, CF4, ST3 1 B

CF4 

39.8 S1BCL028 2.6 Tributary of Military 

Creek 

Open Cut Intermittent 0.18 3 BP4, CF4, ST3 2 B

41 S8BCL005 20 Rock Creek HDD Perennial 0.00 2 CF4, DF3, PEM2, PFO2, 

PSS3, ST2 

67 CPFO

42.3 S8BCL009 11 Tributary of South 

Fork Rock Creek 

Flume Perennial 0.00 2 CF4, CF5, DF3, DF4, 

PFO2, ST2 

46 CDF3PFO

42.7 S1BCL020 6 Tributary of South 

Fork Rock Creek 

Flume Perennial 0.03 2 CF4, DF3, ST2 77 C

43.1 S1BCL021 15 South Fork Rock 

Creek 

HDD Perennial 0.00 2 CF3, CF4, DF3, PEM3, ST2 17 C

DF3 

43.4 S1BCL022 12 Bear Creek HDD Perennial 0.00 2 BP6, CF3, DF3, PFO2, ST2 78 C

PFO
G5-8 

Appendix G5 

Riparian Areas Crossed by the Oregon LNG Pipeline

Milepost Stream ID a

Stream Width b Waterbody c Crossing Method d Stream Type 

Miles to 

Salmonid 

Habitat 

ODFW 

Stream 

Type ODFW Habitat Type e

R

43.5 S1BCL023 1.3 Tributary of Bear 

Creek 

HDD Intermittent 0.04 2 BP6, CF3, PFO2, ST2 81 C

43.7 S1BCL024 1.6 Tributary of Bear 

Creek 

Flume Perennial 0.09 2 BP4, CF3, PEM3, ST2 95 C

43.9 S1BCL025 4 Tributary of Bear 

Creek 

Open Cut Intermittent 0.12 2 BP4, CF3, PEM3, ST2 71 C

44 S1BCL026 3 Tributary of Bear 

Creek 

Open Cut Intermittent 0.11 2 BP4, CF3, PEM3, ST2 92 C

44.2 S1BTI001 6 Bear Creek Flume Perennial 0.18 2 BP4, CF3, PFO2, ST2 82 C44.3 S1BTI002 1.8 Tributary of Bear 

Creek 

Open Cut Intermittent 0.27 3 BP4, CF3, PEM3, ST3 79 C

44.8 S5BTI001 8 Tributary of Wolf 

Creek 

Flume Perennial 2.70 3 CF3, PEM2, ST3 99 C

45.1 S1BTI003 4 Tributary of Wolf 

Creek 

Open Cut Intermittent 2.41 3 CF3, ST3 99 C

47.62 S6BCO002 30 North Fork Wolf 

Creek 

Flume Perennial 0.00 2 CF3, ST2 97 C

48.3 S1BCO000 3 Tributary of North 

Fork Wolf Creek 

Flume Perennial 0.64 3 BP5, CF4, CF5, PEM3, ST3 37 C

50.5 S3BCO012 30 Clear Creek Flume Perennial 0.03 2 BP3, CF4, CF5, DF3, ST2 32 C

DF3 

53.6 S3BCO002 1 Fall Creek Flume Perennial 2.28 2 BP4, CF3, CF4, PEM3, ST2 70 C55.7 S3BCO107 10 Cedar Creek Flume Perennial 0.01 2 CF3, CF4, PEM3, ST2 24 C55.8 S3BCO106 4 Tributary of Cedar 

Creek 

Flume Perennial 0.21 2 BP5, CF3, CF4, CF5, 

PEM3, ST2 

11 CCF5 

57.7 S3BCO100 10 Tributary of Rock 

Creek 

HDD Perennial 0.01 2 BP5, CF4, CF5, ST2 22 C

57.7 S3BCO101 30 Rock Creek HDD Perennial 0.00 2 CF5, ST2 92 C57.7 S3BCO101B 10 Braided Channel to 

Rock Creek 

HDD Perennial 0.00 2 CF5, ST2 87 C

63.8 S3BCO014 30 Nehalem River HDD Perennial 0.00 2 BP6, CF4, DF3, ST2 77 C66.3 S3BCO103 1 Tributary of Oak 

Ranch Creek 

Open Cut Intermittent 0.68 3 BP5, CF5, PEM3, ST3 91 C

67.7 S6BCO004 3 Unnamed Open Cut Intermittent 0.38 3 CF3, CF4, ST3 2 C68 S6BCO003 3 Unnamed Flume Perennial 0.49 3 CF4, ST3 100 70.2 S3BCO003 1 Tributary of 

Clatskanie River 

Flume Perennial 0.59 2 CF4, PEM3, ST2 99 C
G5-9 

Appendix G5 

Riparian Areas Crossed by the Oregon LNG Pipeline

Milepost Stream ID a

Stream Width b Waterbody c Crossing Method d Stream Type 

Miles to 

Salmonid 

Habitat 

ODFW 

Stream 

Type ODFW Habitat Type e

R

70.7 S99CO020 18.5 Clatskanie River Flume Perennial 0.00 2 BP6, CF3, CF4, CF5, ST2 39 C

CF5 

71 S99CO021 1 Unnamed Flume Perennial 0.19 3 CF4, PEM3, ST3 99 C71.8 S5BCO001 2 Little Clatskanie 

River 

Flume Perennial 0.06 2 CF3, CF4, ST2 49 C

72.7 S3BCO008 2 Tributary of Milton 

Creek 

Flume Perennial/ 

Intermittent 0.24 

2 CF3, ST2 100 

73 S3BCO010 12 Milton Creek Flume Perennial 0.02 2 CF4, DF3, PEM/PSS/PFO3, 

ST2 

36 CPEM

73.5 S1BCO004 3 Apilton Creek Open Cut Intermittent 0.54 3 CF3, CF4, PSS/PFO3, ST3 23 C

PSS

73.6 S1BCO005 1 Tributary of Apilton 

Creek 

Open Cut Intermittent 0.58 3 CF3, PEM3, ST3 76 C

74.5 S5BCO011 5 Unnamed Flume Perennial 0.12 2 CF4, DF3, PFO3, ST2 58 C

PFO

74.6 S5BCO010 30 Unnamed Flume Perennial 0.12 2 CF3, CF4, DF3, PFO3, ST2 20 C

DF3

74.9 S6BCO001 22 Milton Creek Flume Perennial 0.00 2 CF4, CF5, DF3, PFO3, ST2 65 C

DF3

76.3 S3BCO110 1 Tributary of Merrill 

Creek 

Open Cut Intermittent 0.24 2 CF3, ST2 100 

76.4 S3BCO017 35 Merrill Creek Flume Perennial 0.00 3 CF3, CF4, PEM/PFO3 1 C

PEM

78.2 S2BCO009 3 Tributary of Merrill 

Creek 

Open Cut Intermittent 0.38 2 CF3, ST2 99 C

78.4 S3BCO122 10 Tributary of Merrill 

Creek 

Flume Perennial 0.20 2 CF3, CF4, PSS/PFO3, ST2 43 C

PSS

79 S3BCO119 1 Tributary of Merrill 

Creek 

Open Cut Intermittent 0.92 2 CF3, PEM3, ST2 69 C

79 S3BCO120 1 Tributary of Merrill 

Creek 

Open Cut Intermittent 0.87 2 CF3, PEM3, ST2 58 C

79.9 S3BCO115 1 Tributary of Merrill 

Creek 

Flume Perennial 2.01 2 CF3, DF3, PEM3, ST2 45 C

81.6 S99CO011 280 Deer Island Slough Flume Perenniall 0.46 2 PEM, PFO, ST 63 82 S3BCO123 20 Dyna Nobel Channel HDD Perennial 0.45 2 BP, NO, PEM, PFO, PSS, 

ST 

21 

82.3 S99CO014 3300 Columbia River HDD Perennial 0.00 2 BP, NO, PEM, ST 83.3 S99CW020 10 Burris Creek Flume Perennial 0.00 NO 85.8 S99CW021 2 Unnamed Flume Perennial 0.36 PEM 
G5-10 

Appendix G5 

Riparian Areas Crossed by the Oregon LNG Pipeline

Milepost Stream ID a

Stream Width b Waterbody c Crossing Method d Stream Type 

Miles to 

Salmonid 

Habitat 

ODFW 

Stream 

Type ODFW Habitat Type e

R

86 S99CW022 2 Unnamed Flume Perennial 0.31 BP, NO, PEM 86.5 S99CW023 3 Unnamed Open Cut Intermittent 0.48 DF, MO, PEM 10 86.7 S99CW025 3 Unnamed Open Cut Intermittent 0.40 BP, DF, PEM 48 86.8 S99CW026 3 Unnamed Flume Perennial 0.39 BP, DF, PEM 65 

__________

a Stream ID numbers beginning in S99 and S38 are for areas with no field access and are based on aerial photography and Pacific Northwest Hydrography Network da

numbers may occur as a result of rounding of mileposts to the nearest tenth of a mile. 

b Widths in feet are stream ordinary high water mark. c Waterbody includes any natural or artificial stream, river, or drainage with perceptible flow at the time of crossing, and other permanent waterbodies. d Construction methods for crossing waterbodies are flume, HDD (horizontal directional drilling), or open-cut. e ODFW habitat types: 

BP = Buildings and developed land CF = Coniferous forest DF = Deciduous forest NO = Agricultural land PEM = Palustrine emergent wetland PFO = Palustrine Forest PSS = Palustrine scrub/shrub wetland ST = Stream 

f Riparian area = DF4, 3, 2; CF4, 3, 2; PFO; PSS. g Riparian area widths are for side of stream with maximum width. 
APPENDIX G6 

LANDSLIDE AND DEBRIS FLOW RISK NEAR WATERBODY CROSSINGS

 

1 

TECHNICAL MEMORANDUM 

Landslide and Debris Flow: Relative Risk Assessment for the 

Bidirectional Project Pipeline 

PREPARED FOR: Peter Hansen/Oregon Pipeline Company, LLC

PREPARED BY: Todd Cotten/CH2M HILL

DATE: November 15, 2013

PROJECT NUMBER: 199863.PT.07; 199863.PP.07

Introduction 

The purpose of this technical memorandum is to evaluate landslide and erosion hazards near 13 stream

crossings selected along the proposed liquefied natural gas (LNG) pipeline (Pipeline) for the Bidirectional

Project (Project). Two types of landslide hazards were evaluated: rotational slides and debris flows. Thirteen

stream crossings along approximately 87 miles of the Pipeline between the Terminal near Warrenton,

Oregon, and the interconnect with the existing Northwest Pipeline LLC (Northwest) pipeline near Woodland,

Washington, were identified for this evaluation based on the following criteria: (1) salmon habitat protected

under the endangered species act (ESA) has been identified in the stream to be crossed, and (2) the

proposed Pipeline construction method consists of traditional cut‐and‐cover in conjunction with fluming of

the stream at the crossing.

Other ESA‐listed streams will be crossed using horizontal directional drilling (HDD) or other trenchless

installation techniques. Trenchless installation methods have less impact in the immediate vicinity of stream

crossings because the primary work areas at the entry and exit locations are typically at least 700 feet away

from the stream and very little disturbance occurs between these work areas. In addition, the Pipeline will

be installed at much greater depths below the stream when installed using HDD or other trenchless

methods. ESA stream crossings where trenchless installation methods are proposed therefore are not

discussed in this memorandum.

The relative risk of two types of landslides hazards, rotational slides and debris flows/rapid erosion, were

assessed for the stream crossings evaluated using a set of risk factors. The primary risk factor evaluated

relates to the presence of landslide hazards that are shown on published geologic hazard mapping and on

landslide inventory mapping developed for the Project. Where mapped landslides or debris flow/rapid

erosion hazards are identified on landslide mapping, the type and location of hazard is summarized for each

of the selected stream crossings. Additional risk factors are evaluated for each crossing location to

determine a relative hazard score for each of the 13 stream crossings evaluated. The risk factors used in the

assessment consisted of the following:

 Slope Steepness

 Landform

 Geology

 Land Use

 Scour Potential

 Channel Migration

Table 1 lists the 13 stream crossings evaluated for landslide potential and the location, by milepost (MP),

along the alignment. All 13 stream crossings evaluated are located in Oregon. The first 3 stream crossings

listed are in Clatsop County and the remaining 10 are in Columbia County.
LANDSLIDE AND DEBRIS FLOW: RELATIVE RISK ASSESSMENT FOR THE BIDIRECTIONAL PROJECT PIPELINE 

2 

TABLE 1

Stream Crossing Summary

Waterbody Stream ID

Milepost

(approximate)

Barrett Slough S5BCL064 4.4

Heckard Creek S1BCL001 7.9

Alder Creek S2BCL008B 31.4

North Fork Wolf Creek S6BCO002 47.6

Clear Creek S3BCO012 50.5

Cedar Creek S3BCO107 55.7

Clatskanie River S99CO020 70.7

Little Clatskanie River S5BCO001 71.8

Milton Creek S3BCO010 73.0

Milton Creek S6BCO001 74.9

Merrill Creek S3BCO017 76.4

Tributary of Merrill Creek S3BCO122 78.4

Deer Island Slough S99CO011 81.6

Note: Milepost refers to the approximate milepost along the Pipeline for the Oregon

Pipeline Project.

ID = identification

This memorandum is organized into the following sections: Landslide Risk Factors, Stream Crossings,

Summary of Landslide Risk Assessment, Limitations, and References.

Landslide Risk Factors 

Landslides can have multiple causes. This section examines the physical, geological, and human‐made causes

of landslides and the risk factors that contribute to landslide potential. The following risk factors are

addressed: mapped landslide hazard, slope steepness, landform, geology, land use, scour potential, and

channel migration. A scoring system for each risk factor was developed in order to determine the relative

landslide hazard for each of the 13 stream crossings.

Mapped Landslide Hazard 

The most critical risk factor affecting the potential for future landslides is judged to be the presence of

existing landslide features in the immediate vicinity of the stream crossings evaluated. The presence of

mapped landslide features is critical because hill slope areas that have failed in the past often remain in a

weakened state, and may tend to fail repeatedly over time. Additionally, large landslide complexes may

have moved several times over thousands of years, with long periods of stability punctuated by episodes of

movement. Thus, previously failed areas are particularly important to identify because they may be

susceptible to future instability.

Two general types of landslide mapping were evaluated: published geologic mapping and landslide hazard

inventory mapping developed specifically for the Project.

Published Hazard Mapping 

In addition to using the landslide hazard inventory mapping developed for the Project, the potential for

landslide hazards to be present in the vicinity of each of the 13 stream crossings has been evaluated by

reviewing published geologic and landslide hazard reports. Some of these reports focus on identifying
LANDSLIDE AND DEBRIS FLOW: RELATIVE RISK ASSESSMENT FOR THE BIDIRECTIONAL PROJECT PIPELINE 

3 

documented historical landslides, others focus on identifying landslide topography, and a third group focus

on identifying potential landslide areas. The following four primary sources of landslide hazard information,

published by the Department of Geology and Mineral Industries (DOGAMI), have been used to identify the

potential hazards for slope instability at each stream crossing:

 Statewide Landslide Information Database for Oregon (SLIDO‐2)

 Slope Failures in Oregon: GIS Inventory for Three 1996/97 Storm Events; Oregon Department of Geology

and Mineral Industries, Special Paper 34 (Hofmeister, 2000)

 “Potential Rapidly Moving Landslide Hazards in Western Oregon” (IMS‐22) (Hofmeister, 2002)

Numerous additional geologic and hazard maps produced by DOGAMI were reviewed to identify potential

landslide hazards at the stream crossings. These maps typically identify the locations of active landslides,

inactive landslides, and landslide debris.

The following maps from DOGAMI Bulletin 79, Environmental Geology of Inland Tillamook and Clatsop

Counties, Oregon, were included in this review:

 Hazard Map of the Birkenfeld Quadrangle (Beaulieu, 1972a)

 Hazard Map of the Saddle Mountain Quadrangle (Beaulieu, 1972b)

Project-Specific Landslide Hazard Inventory Mapping 

A landslide deposit inventory map has been developed for the Project. Landslide inventory maps typically

show the locations of identified historic and prehistoric landslide deposits for an area along with the

characteristics of each landslide. Landslide inventory maps provide basic information for identifying areas of

higher and lower hazards, and landslide susceptibility, which is the first step in risk reduction.

Although areas with mapped landslide deposits are likely to be at higher risk than other areas, these areas

will not automatically experience problems in the future. However, hill slope areas that have failed in the

past often remain in a weakened state, and may tend to fail repeatedly over time. Large landslide complexes

may have moved several times over thousands of years, with long periods of stability punctuated by

episodes of movement. Thus, previously failed areas are particularly important to identify because they may

be susceptible to future instability.

Landslide and mass‐movement topography, recent landslides, and areas that appear to be susceptible to

gullying or rapid erosion were mapped on 1:24,000‐scale, color stereo‐pairs of aerial photographs. For the

portion of the Project between MP 0.0 and approximately MP 47.5, the aerial photographs utilized were

taken in June 2007 by i‐TEN Associates of Portland, Oregon, and the mapping developed in 2009 (CH2M

HILL, 2009). These aerial photographs provide coverage within Clatsop and Tillamook counties, Oregon. In

Columbia County, Oregon, and Cowlitz County, Washington, from approximately MP 47.5 to the end of the

Pipeline near MP 87.8, mapping was conducted using 1:13,560 scale aerial photographs taken in September

2011 by Continental Mapping Consultants, Inc., and the mapping developed in 2011 (CH2M HILL, 2011).

Figures 1 through 18 in the Attachment to this memorandum show the combined 2009 and 2011 landslide

inventory and geologic hazard maps developed for the Project.

In addition, light detection and ranging (LIDAR) data of the alignment are available to assist in delineating

landslide areas in Columbia County. These data provide a detailed image of the ground surface and allow the

identification of the topographic features associated with landslides. According to Burns and Madin (2009),

the use of LIDAR data resulted in identification of 3 to 200 times the number of landslide found with other

data sets, and the accuracy of the spatial extent of the landslides identified was greatly improved with LIDAR

data.

Large areas of mass movement terrain were identified by the following features:

 Steep, arcuate, curved headscarps (pull‐away zone) that form bowl‐shaped areas
LANDSLIDE AND DEBRIS FLOW: RELATIVE RISK ASSESSMENT FOR THE BIDIRECTIONAL PROJECT PIPELINE 

4 

 Irregular, hummocky topography; disrupted or poorly developed drainage patterns and high drainage

density; closed depressions and ponds within the slide mass; transverse ridges, and raised toes and

lobes

 Deep gullies eroded into the weak, disturbed soils and rock

 Concave, nonplanar hillsides with steep upper slopes and flatter irregular lower slopes

 Drainages blocked by slide toes and lobes that often result in low‐gradient streams that have areas of

alluvium “ponded” behind them

The general direction of landslide movement is shown by an arrow. Obvious younger headscarps and

smaller scarps within the slide mass are delineated on the landslide inventory mapping. Scarps in thick trees

are more difficult to identify, but often have semi‐circular logging roads following them around heads of

drainages and are distinguished from “V” shaped drainage heads. Large areas of “mass movement terrain”

are delineated by a triangular stippled pattern (similar to mass movement terrain shown on previous

published mapping by Beaulieu, 1973). The landslide masses are typically downslope from the arcuate

headscarps, which are outlined on the maps.

As landslides age and are subjected to erosion and weathering, the topographic features become more

subdued and difficult to identify. Outlines of older landslides with a lower confidence of identification are

shown by dashed outlines. The landslide inventory mapping also shows features such as rock quarries and

areas of ponded stream alluvium. Generally, features such as hummocky topography, steep headscarps,

gullies, ridges, and closed depressions were more easily observed in clearcut areas on the aerial

photographs.

Areas that appear to be more susceptible to rapid erosion and gullying were also delineated on the aerial

photographs. These areas are where the proposed alignment crosses side slopes that exhibit debris flows

and steep‐sided, deep erosional channels in weak soils. These areas are shown by an arrow. Often, in

landslide areas, the erosional channels do not follow the “fall‐line” towing to diversion by the irregular slide

mass (deviation from the expected drainage patterns). Steep‐sided gullies could be observed in the landslide

mass, where the weakened, disturbed slide mass is more easily eroded.

Slope angles are often considered in landslide susceptibility and general landslide hazard, particularly for the

hazard of potentially rapid‐moving landslides. However, in the Project vicinity, the presence of large areas of

landslide topography appears to be related more to lithology and areas of weak, interbedded sedimentary

rocks rather than steeper slope angles. For example, stronger rocks such as basalt flows, intrusive basalts,

and sandstones form steeper, more stable slopes that are not as susceptible to sliding. The steepest slopes

along the Project are found in areas underlain by these types of rocks, and they actually exhibit fewer

landslides despite being steeper. For example, between approximately MP 40 and 44, slopes are steep but

fewer landslides were mapped because much of this area is underlain by sandstones (Sunset Highway

member). In fact, Beaulieu (1973) notes that “slopes within the slide mass are gentler than those of the

surrounding intact terrain.” Steep slopes thus do not necessarily equate to greater landslide hazard. Steep

slopes are often underlain by harder rock, and are actually more stable. For example, in the Birkenfeld

Quadrangle, many large areas of landslides form flatter terrain, especially where very old slide masses are

highly eroded and exhibit subdued topography and low slope angles.

Limitations of the Data and Landslide Inventory Mapping. Landslide inventory mapping is based on

available aerial photographs and LIDAR data. Mapping is subject to interpretation or misinterpretation of

the data, and landslides can be missed or overlooked. No field checking or verification of the mapping was

conducted for Columbia County. Limited field checks were conducted for Clatsop County. Field checking

tends to be time consuming and expensive and detailed geologic mapping is generally not completed as part

of the Federal energy Regulatory Commission (FERC) permitting process. Limitations of the landslide

inventory mapping include the following:
LANDSLIDE AND DEBRIS FLOW: RELATIVE RISK ASSESSMENT FOR THE BIDIRECTIONAL PROJECT PIPELINE 

5 

 At this level of inventory mapping, landslides were not classified by type (i.e., slump/earthflow versus

debris flow).

 Features of older landslide deposits are more difficult to identify because of erosion and the tendency to

be covered with younger deposits.

 The ages of landslides were not estimated, and landslides were not assigned to historic and pre‐historic

categories (i.e., younger and older than 150 years). However, landslides with less‐recognizable features

are generally interpreted to be older, and are delineated by dashed lines.

 Landslides were not classified as “deep” or “shallow” and the depths of landslides were not estimated.

However, where a larger, deeper slide mass was recognizable, the mass was shown by a triangular

stippled pattern.

 Landslide inventory/deposit mapping is NOT a map or complete inventory of locations of all past

landslides.

 Very small landslide deposits cannot always be identified because of the resolution of LIDAR data, scale

of aerial photos, and forest cover. Also, some areas of landslide terrain extend over several square miles

and extend beyond the mapping corridor.

 The aerial photographs and LIDAR data are “snapshot” views of the existing landscape at the time of the

photographs or generation of terrain model. New landslides may occur as the result of increased

precipitation or changes in land use in the vicinity.

Table 2 presents the scoring system used for the risk related to a mapped landslide hazard. Because the

presence of mapped landslide hazard is judged to be the single most important factor in predicting the

possibility of future landslide events, the scoring range for this criterion is set between zero and 10, where

other factors have a range between 0 and six. The system was developed based on the relative distance of

each stream crossing to the mapped hazard. A score of 0 represents the lowest relative hazard for a mapped

landslide area and a score of 9 represents the highest relative hazard.

TABLE 2

Mapped Landslide Hazard Scoring System

Mapped Landslide Hazard Score

No documented or mapped landslide hazard in the vicinity of the stream crossing 0

Mapped areas of low landslide hazard   2

Mapped areas of landslide topography or areas of moderate landslide hazard 5

Areas meeting one of the following conditions:

1. Steam crossing is in the immediate vicinity of potential Gullying/Rapid Erosion/or Debris Flow

2. Within mapped area of inferred landslide

3. Area shown as high landslide hazard

8

Adjacent to recent documented landslide or within mapped landslide area 10

Slope Steepness 

An important risk factor affecting the potential for landslides is slope steepness in the general vicinity of

each of the 13 stream crossings evaluated. For this evaluation, slope refers to the steepness of the ground,

or the height the slope rises in a given distance. For example, if the elevation difference between the toe of

a slope and the crest of a slope is 50 feet and the horizontal distance between the toe and crest of the slope

is 100 feet, an average slope geometry of 50 percent exists. As a general rule, the steeper the slope, the

more susceptible it will be to landslides. This theory has been corroborated by a number of studies,

including one study by the Oregon Department of Forestry (ODF), which found that all debris flows in the
LANDSLIDE AND DEBRIS FLOW: RELATIVE RISK ASSESSMENT FOR THE BIDIRECTIONAL PROJECT PIPELINE 

6 

study areas were initiated on slopes greater than 40 percent steepness and most landslides (86 percent)

were initiated where slope steepness was measured to be over 70 percent (Robison et al., 1999).

Various land survey studies have been performed in the past for each of the 13 stream crossings evaluated.

These studies provided contour information that CH2M HILL used to determine the character of any slopes

located at or near each crossing. As a result, the scoring system for slope steepness presented in Table 3 was

developed based on the general characteristics of the slopes at each crossing and previous experience

regarding the stability of various slopes comprising materials native to the region. A score of 0 represents

the lowest relative hazard regarding slope steepness and a score of 6 represents the highest relative hazard.

TABLE 3

Slope Steepness Scoring System

Slope Steepness

(Percent) Score

Less than 10 0

10 to 20 2

20 to 30 3

30 to 40 4

40 to 50 5

Greater than 50 6

Landform 

The shape of slopes, referred to as landform, has an impact on the potential for landslides and debris flows.

Sharply convergent (concave) slopes tend to develop thicker soil deposits and are locations where drainage

is concentrated (Dietrich and Dunne, 1978). Many studies report that convergent slope locations have

higher landslide hazard than straight (planar) and divergent (convex) landforms (Tsukamoto et al., 1982;

Reneau and Dietrich, 1987; Benda and Cundy, 1990; May, 1998; Millard, 1999). While landslides and debris

flows do occur on slopes with no apparent distinctive landform, convergent landforms tend to have a higher

landslide occurrence in western North America (Hofmeister, 2002). Table 4 presents the scoring system used

for landform. The system was developed based on the general shape of slopes at the location of each

stream crossing. A score of 1 represents the lowest relative hazard regarding geology and a score of 5

represents the highest relative hazard.

TABLE 4

Landform Scoring System

Landform Score*

Divergent (convex) shape of slopes at stream crossing 1

Straight (planar) shape of slopes at stream crossing 3

Convergent (concave) shape of slopes at stream crossing 5

*A score of zero (0) will be applied when there are no slopes or slopes of less than

10 percent steepness in the vicinity of the steam crossing.

Geology 

The geology of Oregon is complex and varies widely across the state. Much of this variation can be

attributed to the offshore Cascadia Subduction Zone, which is where the Juan de Fuca Plate is being actively

subducted beneath the western margin of the North American Plate. The ongoing subduction has created

accretionary wedges, fore‐arc sediment basins, uplift of the Oregon Coast Range, and a seismically active
LANDSLIDE AND DEBRIS FLOW: RELATIVE RISK ASSESSMENT FOR THE BIDIRECTIONAL PROJECT PIPELINE 

7 

area with numerous faults, volcanoes, mountains, and valleys (Orr et al., 1992). The geology exclusive to

each stream crossing site can have a large impact on the landslide and debris flow hazard. The following

sources were used to identify the mapped geology for each of the 13 stream crossings evaluated:

 Oil and Gas Investigation of the Astoria Basin, Clatsop and Northwest Tillamook Counties, Northwest

Oregon (Niem and Niem, 1985)

 Oregon Geologic Data Compilation (OGDC) Release 5. OGDC‐5. (DOGAMI, 2009).

Table 5 presents the scoring system used for geology. The system was developed based on the established

characteristics of geologic formations mapped at each stream crossing. A score of 1 represents the lowest

relative hazard regarding geology and a score of 5 represents the highest relative hazard.

TABLE 5

Geology Scoring System

Geology Score

Geology mapped at stream crossing known to not be susceptible to landsliding hazard (i.e., intact rock) 1

Geology mapped at stream crossing unknown or inconclusive regarding susceptibility to landsliding hazard 3

Geology mapped at stream crossing known to be susceptible to landsliding hazard 5

Land Use 

Impacts from human activity can have an adverse effect on the stability of slopes. For this landslide risk

assessment, the primary land use activity that could potentially affect the stability of slopes at the 13 stream

crossing evaluated is logging and the removal of vegetation at or near each location. Most evidence suggests

that the more vegetation present at a site, the lower its susceptibility to landslides. Both vegetative type and

cover can significantly impact the potential for landslides (Hofmeister, 2002). Therefore, aerial photographs

were studied in order to identify the stream crossings that are located in areas in proximity to timber

harvesting and clearcutting activities. Table 6 presents the scoring system used for land use. A score of 1

represents the lowest relative hazard regarding land use and a score of 3 represents the highest relative

hazard.

TABLE 6

Land Use Scoring Assessment

Land Use Score

No evidence of timber harvesting or clearcutting activities in vicinity of the stream crossing 1

Evidence of timber harvesting or clearcutting activities in vicinity of the stream crossing 3

Scour Potential 

Separate analyses were performed to evaluate the potential for scour at the 13 stream crossings. These

analyses used characteristics such as stream segment slope, channel confinement, and entrenchment.

Stream slope (gradient) at proposed Pipeline crossings were determined from field reconnaissance surveys.

Where field reconnaissance surveys were not conducted, channel gradient was determined from 1:24,000

U.S. Geological Survey (USGS) topographic maps by measuring the distance between two contour lines

encompassing the Pipeline crossing or by using Oregon 10‐meter Digital Elevation Model elevations. Channel

confinement was determined by measuring the valley width or floodplain (distance between contour lines

on either side of the channel based on 1:24,000 USGS topographic map) and comparing it to the channel

width (bankfull width).
LANDSLIDE AND DEBRIS FLOW: RELATIVE RISK ASSESSMENT FOR THE BIDIRECTIONAL PROJECT PIPELINE 

8 

After determining channel gradient, channel confinement, and valley width at the Pipeline crossing, streams

were grouped into categories based on their similarities and channel characteristics. Streams with specific

similarities are expected to have similar responses to disturbance or are predisposed to specific conditions.

These responses or conditions are based in part on the Washington Department of Natural Resources

(WDNR) Watershed Assessment Methodology (1994) Channel Response Matrix. In addition, the Rosgen

channel type (Rosgen, 1996) collected during field reconnaissance surveys was used to verify and support

WDNR Channel Response Matrix characteristics. Table 7 presents a summary of the categories the stream

crossings were grouped into and the associated scoring system used for scour potential. A score of 1

represents the lowest relative hazard regarding scour potential and a score of 5 represents the highest

relative hazard.

TABLE 7

Scour Potential Scoring System

Scour Potential Score

None or Slight 1

Moderate 2

Moderate/Severe 3

Severe 4

Severe (Mass‐Wasting Dominated) 5

Channel Migration 

Channel migration can have an adverse effect on stability of slopes if the stream channel erodes into the toe

or base of a slope. As with scour potential, separate analyses were performed to determine the potential for

channel migration at the proposed stream crossings. The analyses considered the valley width, channel

width, and the gradient of each stream in order to determine the potential for channel migration. Table 8

presents a summary of the scoring system used for channel migration as it relates to landslide hazard. A

score of 0 represents the lowest relative hazard regarding channel migration and a score of 3 represents the

highest relative hazard.

TABLE 8

Channel Migration Scoring Assessment

Channel Migration Score

Minimal bank erosion or channel migration potential 0

Bank erosion and channel migration 3

Summary 

A total of seven risk factors that have varying levels of influence on landslide hazard were evaluated for each

stream crossing. As shown by the scoring systems presented in Tables 2 through 8, mapped landslide hazard

has been determined to be the most critical of the seven risk factors. However, each risk factor does impact

the landslide hazard at each of the 13 stream crossings. Landslides often have several causes, some of which

are listed above, but only one trigger (Varnes, 1978). A trigger is an external stimulus such as intense rainfall

or a seismic event, and the hazard associated with these triggers is considered to be relatively equal across

all of the proposed stream crossings.

Stream Crossings 

This section summarizes the evaluation of the landslide hazard at each of the 13 stream crossings. A score

for each landslide hazard risk factor is presented with a justification for that score. A sum of each risk factor
LANDSLIDE AND DEBRIS FLOW: RELATIVE RISK ASSESSMENT FOR THE BIDIRECTIONAL PROJECT PIPELINE 

9 

score for a stream crossing is presented as the total score in order to quantify the relative landslide hazard

at that specific stream crossing.

Barrett Slough (S5BCL064) 

The Barrett Slough (stream ID S5BCL064) crossing is located at MP 4.4 along the Pipeline alignment in an

alluvial valley created by the Lewis and Clark River approximately 2 miles south of the confluence of the

Lewis and Clark River and Youngs Bay.  

The width and depth of the slough channel at the crossing are approximately 12 and less than 3 feet,

respectively. Table 9 presents a score value and justification for each risk factor evaluated for this crossing.

Stream crossing Figure 6A‐5 presents an aerial view and cross‐section of the crossing.

TABLE 9

Scoring Assessment—Barrett Slough (S5BCL064)

Risk Factor Score Justification

Mapped Landslide Hazard 0 No documented or mapped landslide hazard in vicinity of crossing.

Slope Steepness 0 Stream located in alluvial valley where topography is primarily flat. Slope geometry

approximately equal to 0.

Landform 0 No slopes adjacent to stream crossing.

Geology 3 Geology at crossing mapped to be quaternary alluvium (Qal) consisting of unconsolidated flood

plain deposits of clay, silt, sand, and basalt gravel (Niem and Niem, 1985).

Land Use 1 Land use primarily consists of agriculture. Stream setting is an alluvial valley with sporadic trees.

No timber harvesting in general vicinity due to stream location.

Scour Potential 1 Analysis results show none or slight scour potential.  

Channel Migration 3 Analysis results show bank erosion and channel migration potential.

Total Score 8

Heckard Creek (S1BCL001) 

The Heckard Creek (stream ID S1BCL001) crossing is located at MP 7.9 for the main Pipeline alignment in the

foothills along the western flank of the Oregon Coast Range in a forested setting.  

The width and depth of the creek channel at the crossing are approximately 10 and 3 feet, respectively.

Table 10 presents a score value and justification for each risk factor evaluated for this crossing. Figure 6A‐8

presents an aerial view and cross‐section of the stream crossing.

TABLE 10

Scoring Assessment—Tributary of Heckard Creek (S1BCL001)

Risk Factor Score Justification

Mapped Landslide Hazard 5 Landslide topography mapped at crossing location (SLIDO‐2).

Slope Steepness 2 Stream crossing located in foothills along western flank of Coast Range. Average slope geometry

of slope located south of crossing approximately equal to 15 to 20 percent.

Landform 3 General shape of slopes located at crossing is planar.

Geology 1 Geology at crossing mapped to be Smuggler Cove Formation (Tsc2), which consists primarily of

thick‐bedded bioturbated tuffaceous claystone and siltstone (Niem and Niem, 1985).

Land Use 3 Evident that predominant land use activity in the general vicinity of the crossing is timber

harvesting.

Scour Potential 1 Analysis results show a slight potential for scour.  

Channel Migration 3 Analysis results show bank erosion and channel migration potential.
LANDSLIDE AND DEBRIS FLOW: RELATIVE RISK ASSESSMENT FOR THE BIDIRECTIONAL PROJECT PIPELINE 

10 

TABLE 10

Scoring Assessment—Tributary of Heckard Creek (S1BCL001)

Risk Factor Score Justification

Total Score 18   

Alder Creek (S2BCL008B) 

The Alder Creek (stream ID S2BCL008B) crossing is located at MP 31.4 of the Pipeline alignment in the

Oregon Coast Range in a forested setting approximate 1 mile east‐northeast from Camp 18 and

US Highway 26.  

The width and depth of the creek channel at the crossing are approximately 13 and 4 feet, respectively.

Table 11 presents a score value and justification for each risk factor evaluated for this crossing. Figure 6A‐10

presents an aerial view and cross‐section of the stream crossing.

TABLE 11

Scoring Assessment—Alder Creek (S2BCL008B)

Risk Factor Score Justification

Mapped Landslide Hazard 8 Stream is near potential gullying/rapid erosion location. Crossing location is also in area

mapped to have mass movement topography (Beaulieu, 1972b).

Slope Steepness 4 Stream crossing located in Oregon Coast Range. Average slope geometry of slope located

south of crossing approximately equal to 30 to 40 percent.

Landform 1 General shape of steeper slopes at stream crossing is divergent.

Geology 1 Geology at crossing mapped to be either Sager Creek Formation (Tg) or Keasey Formation (Tkj).

Sager Creek Formation primarily consists of well‐laminated micaceous and carbonaceous

mudstone. Keasey Formation primarily consists of thin‐bedded to laminated tuffaceous to

glauconitic mudstone (Niem and Niem, 1985).

Land Use 3 Evident that predominant land use activity in the general vicinity of the crossing is timber

harvesting. Clearcut located adjacent to stream crossing.

Scour Potential 3 Analysis results show a moderately severe potential for scour.  

Channel Migration 0 Analysis results show no or minimal potential for bank erosion or channel migration.

Total Score 20

North Fork Wolf Creek (S6BCO002) 

The North Fork Wolf Creek (stream ID S6BCO002) crossing is located at MP 47.6 along the Pipeline in the

Oregon Coast Range in a forested setting approximately 1,200 feet north of US Highway 26 about three‐

quarters of a mile west of the intersection with North Fork Wolf Creek Road.

The width and depth of the creek channel at the crossing are approximately 35 and 5 feet, respectively.

Table 12 presents a score value and justification for each risk factor evaluated for the crossing. Figure 6A‐14

presents an aerial view and cross‐section of the stream crossing.
LANDSLIDE AND DEBRIS FLOW: RELATIVE RISK ASSESSMENT FOR THE BIDIRECTIONAL PROJECT PIPELINE 

11 

TABLE 12

Scoring Assessment—North Fork Wolf Creek (S6BCO002)

Risk Factor Score Justification

Mapped Landslide Hazard 8 Stream is near potential gullying/rapid erosion location. Crossing location is also adjacent to

area mapped as landslide topography (CH2M HILL, 2013), potential rapidly moving landslide

(Hofmeister, 2002).

Slope Steepness 5 Stream crossing located in Oregon Coast Range. Geometry of slopes adjacent to crossing

ranges from 40 to 50 percent on south side of creek and between 20 and 30 percent on north

side of creek.

Landform 3 General shape of slopes located at crossing is planar.

Geology 5 Geology consists of marine sedimentary rock. Deep landslides are uncommon in this geology,

but shallow landslides are known to occur.

Land Use 3 Evidence of clearcutting activities northeast of the stream crossing.

Scour Potential 2 Analysis results show a slight to moderate potential for scour at the stream crossing.

Channel Migration 0 Minimal bank erosion or channel migration potential.

Total Score 26

Clear Creek (S3BCO012) 

The Clear Creek (stream ID S3BCO012) crossing is located at MP 50.5 along the Pipeline alignment in the

Oregon Coast Range in a forested setting approximately 2 miles north of US Highway 26 about 2 miles west

of Timber Road. The width of the creek channel at the crossing is approximately 30 feet and the depth of the

creek is unknown. Table 13 presents a score value and justification for each risk factor evaluated for the

crossing. Figure 6A‐15 presents an aerial view and cross‐section of the stream crossing.

TABLE 13

Scoring Assessment—Clear Creek (S3BCO012)

Risk Factor Score Justification

Mapped Landslide Hazard 2 No documented or mapped landslide hazard at crossing, but Potential Rapidly Moving

Landslide located northeast of crossing locations (Hofmeister, 2002).

Slope Steepness 3 Slope ranges between 20 and 30 percent with steeper slopes located northeast of stream

crossing.

Landform 1 Slopes on either side of stream crossing are slightly divergent.

Geology 3 Geology at crossing mapped to Marine Sedimentary Rock consisting of sandstone –

specifically Cowlitz Formation, Clark and Wilson Sandstone Member (Tccw) (DOGAMI, 2009).

Land Use 3 Evidence of clearcutting activities east of the stream crossing.

Scour Potential 3 Analysis results show a moderate to severe potential for scour.

Channel Migration 0 Analysis results show minimal potential for bank erosion and channel migration.

Total Score 15

Cedar Creek (S3BCO107) 

The Cedar Creek (stream ID S3BCO107) crossing is located at MP 55.7 of the Pipeline alignment in the

Oregon Coast Range in a forested setting approximately 1 mile west of the Vernonia Airfield and

approximately 0.15 mile southwest of Koster Road.
LANDSLIDE AND DEBRIS FLOW: RELATIVE RISK ASSESSMENT FOR THE BIDIRECTIONAL PROJECT PIPELINE 

12 

The width and depth of the creek channel at the crossing are approximately 20 and 5 feet, respectively.

Table 14 presents a score value and justification for each risk factor evaluated for the crossing. Figure 6A‐16

presents an aerial view and cross‐section of the stream crossing.

TABLE 14

Scoring Assessment—Cedar Creek (S3BCO107)

Risk Factor Score Justification

Mapped Landslide Hazard 8 Mapped landslide located south of stream crossing with small areas of rapid erosion and

gullying potential (CH2M HILL, 2013).  

Slope Steepness 4 Creek is deeply incised with slopes immediately adjacent to the creek crossing ranging in

steepness between 30 and 40percent. Slopes further from incised creek are flatter with typical

slopes less than 10 percent.  

Landform 3 General shape of slopes located at crossing is planar.

Geology 3 Geology at crossing mapped to be Keasey Formation (Tk), which primarily consists of

tuffaceous sedimentary rocks (DOGAMI, 2009).

Land Use 3 Evidence of clearcutting activities north of the stream crossing.

Scour Potential 2 Analysis results show slight to moderate scour potential.  

Channel Migration 0 Minimal potential for bank erosion and channel migration potential.

Total Score 23

Clatskanie River (S99CO020) 

The Clatskanie River (stream ID S99CO020) crossing is located at MP 70.7 of the main Pipeline alignment on

the east side of the Oregon Coast Range. The crossing is in a forested area approximate 0.1 mile west of

Schaffer Road, 2 miles north of its intersection with Pittsburg Road, and about 10 miles west of the Columbia

River.

The width of the creek channel is estimated to be approximately 20 and the depth of the creek is expected

to range between 2 feet and 7 feet for the majority of the year. Table 15 presents a score value and

justification for each risk factor evaluated for the crossing. Figure 6A‐19 presents an aerial view and cross‐

section of the stream crossing.

TABLE 15

Scoring Assessment—Clatskanie River (S39CLI001)

Risk Factor Score Justification

Mapped Landslide Hazard 8 Mapped landslide located immediately west of stream crossing with small areas of rapid erosion

and gullying potential (CH2M HILL, 2013).  

Slope Steepness 4 Geometry of slopes adjacent to crossing generally range from 25 to 35 percent.

Landform 3 General shape of slopes located at crossing is planar.

Geology 5 Geology at crossing mapped Scappoose Formation (Ts) consisting of sandstone (DOGAMI, 2009).

However, it is believe that shallow deposits of recent quaternary alluvium (Qal) overly the

sandstone at this crossing location (CH2M HILL, 2013).  

Land Use 3 The stream crossing is immediately east of a clearcut.  

Scour Potential 1 Analysis results show none to slight scour potential.  

Channel Migration 0 Minimal potential for bank erosion and channel migration potential.

Total Score 24   
LANDSLIDE AND DEBRIS FLOW: RELATIVE RISK ASSESSMENT FOR THE BIDIRECTIONAL PROJECT PIPELINE 

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Little Clatskanie River (S5BCO001) 

The Little Clatskanie River (stream ID S5BCO001) crossing is located at MP 71.8 of the Pipeline alignment in

the Oregon Coast Range, approximately 0.2 miles east of Janshaw Road.

The width and depth of the creek channel at the time of a site visit were less than 10 and less than 2 feet,

respectively. Table 16 presents a score value and justification for each risk factor evaluated for the crossing.

Figure 6A‐20 presents an aerial view and cross‐section of the stream crossing.

TABLE 16

Scoring Assessment—Little Clatskanie River (S5BCO001)

Risk Factor Score Justification

Mapped Landslide Hazard 8 Mapped landslide located west of stream crossing with potential for rapid erosion and/or

gullying at stream crossing (CH2M HILL, 2013).  

Slope Steepness 2 Geometry of slopes adjacent to crossing ranges from 10 to 20 percent.

Landform 3 General shape of slopes located at crossing is planar.

Geology 1 Geology at crossing mapped Columbia River Basalt Group (Tcr) consisting of basalt rock

(DOGAMI, 2009). However, it is believe that shallow deposits of recent quaternary alluvium

(Qal) overly the basalt at this crossing location (CH2M HILL, 2013).

Land Use 3 The stream crossing is immediately west of a clearcut.  

Scour Potential 3 Analysis results show moderate to severe scour potential.

Channel Migration 0 Minimal potential for bank erosion and channel migration potential.

Total Score 20   

Milton Creek (S3BCO010) 

The Milton Creek (stream ID S3BCO010) crossing is located at MP 73.0 of the Pipeline alignment in the

Oregon Coast Range approximately 0.1 mile east of S Canaan Road.

At the time of the field visit to evaluate the stream characteristics, the width and depth of the creek channel

at the crossing were approximately 10 and less than 2 feet, respectively. Table 17 presents a score value and

justification for each risk factor evaluated for the crossing. Figure 6A‐21 presents an aerial view and cross‐

section of the stream crossing.

TABLE 17

Scoring Assessment—Milton Creek (S3BCO010)

Risk Factor Score Justification

Mapped Landslide Hazard 8 Mapped potential for rapid erosion and/or gullying at stream crossing (CH2M HILL, 2013).

Slope Steepness 4 Geometry of slopes adjacent to crossing generally range from 25 to 35 percent.

Landform 1 Slopes on either side of stream crossing are slightly divergent.

Geology 1 Geology at crossing mapped Columbia River Basalt Group (Tcr) consisting of basalt rock

(DOGAMI, 2009). However, it is believe that shallow deposits of recent quaternary alluvium

(Qal) overly the basalt at this crossing location (CH2M HILL, 2013).

Land Use 1 No evidence of timber harvesting or clearcutting activities in vicinity of the stream crossing.

Scour Potential 3 Analysis results show moderate to severe scour potential.

Channel Migration 0 Minimal potential for bank erosion and channel migration potential.

Total Score 18
LANDSLIDE AND DEBRIS FLOW: RELATIVE RISK ASSESSMENT FOR THE BIDIRECTIONAL PROJECT PIPELINE 

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Milton Creek (S6BCO001) 

The Milton Creek (stream ID S6BCO001) crossing is located at MP 74.9 of the Pipeline alignment in the

Oregon Coast Range. The crossing is approximately 0.2 mile south of Pinkney Road.

At the time of the field visit to evaluate the stream characteristics, the width of the creek channel at the

crossing was approximately 20 feet. No information was obtained relative to the depth of the creek channel.

Table 18 presents a score value and justification for each risk factor evaluated for the crossing. Figure 6A‐22

presents an aerial view and cross‐section of the stream crossing.

TABLE 18

Scoring Assessment—Milton Creek (S6BCO001)

Risk Factor Score Justification

Mapped Landslide Hazard 5 Mapped landslide hazards both north and south of crossing location with potential for gullying

and/or rapid erosion upstream and downstream of crossing, but not directly at crossing

location.  

Slope Steepness 5 Geometry of slopes adjacent to crossing generally range from 40 to 50 percent east of the

stream crossing and less than 20 percent west of the stream crossing.

Landform 1 Slopes on either side of stream crossing are divergent.

Geology 5 Geology at crossing mapped to be Scappoose Formation, Oligocene Sediment (Tos) which

primarily consists of sandstone (DOGAMI, 2009). However, it is believe that shallow deposits of

recent quaternary alluvium (Qal) overly the sandstone at this crossing location (CH2M HILL,

2013).

Land Use 3 The stream crossing is west of a clearcut area.  

Scour Potential 3 No data are available for the relative scour potential at the crossing. Therefore, a medium score

of 3 is used.  

Channel Migration 0 Minimal potential for bank erosion and channel migration potential.

Total Score 22

Merrill Creek (S3BCO017) 

The Merrill Creek (stream ID S3BCO017) crossing is located at MP 76.4 of the Pipeline alignment in the

foothills of the Oregon Coast Range, approximately 1.1 miles due south of the intersection of Hawks Run

Lane and Canaan Road.

At the time of the field visit to evaluate the stream characteristics, the full width of the stream channel was

noted at 35 feet but no information was recorded on the width or depth of the stream. Table 19 presents a

score value and justification for each risk factor evaluated for the crossing. Figure 6A‐23 presents an aerial

view and cross‐section of the stream crossing.
LANDSLIDE AND DEBRIS FLOW: RELATIVE RISK ASSESSMENT FOR THE BIDIRECTIONAL PROJECT PIPELINE 

15 

TABLE 19

Scoring Assessment—Merrill Creek (S3BCO017)

Risk Factor Score Justification

Mapped Landslide Hazard 8 Mapped landslide hazards in the vicinity, but not directly at the crossing location. Potential for

gullying and/or rapid erosion in the vicinity of the crossing location.  

Slope Steepness 3 Geometry of slopes adjacent to crossing generally range from 20 to 30 percent east of the

stream crossing and less than 20 percent west of the stream crossing.

Landform 5 Slope to the east of the crossing is divergent and the slope to the west of the crossing is

convergent.

Geology 1 Geology at crossing mapped Columbia River Basalt Group (Tcr) consisting of basalt rock

(DOGAMI, 2009).  

Land Use 1 No evidence of recent timber harvesting or clearcutting in the vicinity of the stream crossing.

Scour Potential 2 Analysis results show slight to moderate scour potential.  

Channel Migration 0 Minimal potential for bank erosion and channel migration potential.

Total Score 20

Tributary of Merrill Creek (S3BCO122) 

The Tributary of Merrill Creek (stream ID S3BCO122) crossing is located at MP 78.4 of the Pipeline alignment

in the foothills of the Oregon Coast Range, approximately 0.8 mile south of the terminus of Hills Haven

Avenue.

At the time of the field visit to evaluate the stream characteristics, the width of the creek channel at the

crossing was approximately 10 feet. No information was obtained relative to the depth of the stream. Table

20 presents a score value and justification for each risk factor evaluated for the crossing. Figure 6A‐24

presents an aerial view and cross‐section of the stream crossing.

TABLE 20

Scoring Assessment—Tributary of Merrill Creek (S3BCO122)

Risk Factor Score Justification

Mapped Landslide Hazard 8 Both sides of stream crossing are shows as landslide topography. Multiple small areas where

there is a potential for gullying and/or rapid erosion are located in the vicinity of the crossing

location.  

Slope Steepness 4 Geometry of slopes adjacent to crossing ranges from 30 to 40 percent.

Landform 3 Slope to the east of the crossing is divergent and the slope to the west of the crossing is planar.

Geology 5 Geology at crossing mapped Scappoose Formation (Ts) consisting of sandstone (DOGAMI,

2009). However, it is believe that shallow deposits of recent quaternary alluvium (Qal) overly

the sandstone at this crossing location (CH2M HILL, 2013).  

Land Use 1 No evidence of recent timber harvesting or clearcutting in the vicinity of the stream crossing.

Scour Potential 2 Analysis results show slight to moderate scour potential.  

Channel Migration 0 Minimal potential for bank erosion and channel migration potential.

Total Score 23

Deer Island Slough (S99CO011) 

The Deer Island Slough (stream ID S99CO011) crossing is located at MP 81.6 of the Pipeline alignment at the

edge of the Coast Range in the Willamette Valley ecoregion. The crossing is immediately adjacent to the

Columbia River and is bordered on both sides by open areas.  
LANDSLIDE AND DEBRIS FLOW: RELATIVE RISK ASSESSMENT FOR THE BIDIRECTIONAL PROJECT PIPELINE 

16 

The proposed Pipeline alignment is along a flood control levee that also serves as an access road, called Dike

Road, to Deer Island. The slough flows under Dike Road via culverts. The planned location for the Pipeline

would be along the toe of the existing levee, above the culverts that carry water of the Deer Island Slough.

Therefore, the proposed location of the Pipeline would not have any impacts to the landslide potential at

this crossing. However, an assessment of the potential hazard is included to evaluate the potential hazard at

the crossing in the unlikely event that the location of the Pipeline is modified.  

At the time of the field visit to evaluate the stream characteristics, the width of the creek channel at the

crossing was approximately 38 feet. No information was obtained relative to the depth of the stream. Table

21 presents a score value and justification for each risk factor evaluated for the crossing. Figure 6A‐25

presents an aerial view and cross‐section of the stream crossing.

TABLE 21

Scoring Assessment—Deer Island Slough (S99CO011)

Risk Factor Score Justification

Mapped Landslide Hazard 0 No documented or mapped landslide hazard in vicinity of crossing.

Slope Steepness 0 Stream located in alluvial valley where topography is primarily flat. Slope geometry

approximately equal to 0.

Landform 0 Slopes adjacent to stream crossing are less than 10 percent.  

Geology 5 Geology at crossing mapped to be artificial fill (af), which makes up the Dike Road. The

material around the dike road is mapped as Alluvium (Qa) (DOGAMI, 2009).

Land Use 1 No timber harvesting in general vicinity because of stream location.

Scour Potential 3 Analysis results show moderate to severe scour potential.  

Channel Migration 3 Analysis results show bank erosion and channel migration potential.

Total Score 12

Summary of Landslide Risk Assessment 

The systematic assessment methodology described in this technical memorandum resulted in the

quantification of relative landslide hazard at each of the 13 selected Pipeline stream crossings. Table 22

presents the range of total score values relative to the landslide hazard.

TABLE 22

Relative Landslide Hazard

Total Score Relative Landslide Hazard

10 or less Very Low

11 to 15 Low

16 to 20 Moderate

21 to 25 High

25 and greater Very High

Table 23 presents a summary of the scores for each risk factor applied to each of the 13 selected stream

crossings, as well as the total score and corresponding relative landslide hazard.
LANDSLIDE AND DEBRIS FLOW: RELATIVE RISK ASSESSMENT FOR THE BIDIRECTIONAL PROJECT PIPELINE 

17 

TABLE 23

Landslide Risk Assessment Summary

Waterbody Stream ID

Mapped

Landslide

Hazard

Slope

Steepness Landform Geology

Land

Use

Scour

Potential

Channel

Migration

Total

Score

Relative

Landslide

Hazard

Barrett Slough S5BCL064 0 0 3 0 1 1 3 8 Very Low

Heckard Creek S1BCL001 5 2 3 1 3 1 3 18 Moderate

Alder Creek S2BCL008B 8 4 1 1 3 3 0 20 Moderate

North Fork Wolf Creek S6BCO002 8 5 3 5 3 2 0 26 Very High

Clear Creek S3BCO012 2 3 1 3 3 3 0 15 Low

Cedar Creek S3BCO107 8 4 3 3 3 2 0 23 High

Clatskanie River S99CO020 8 4 3 5 3 1 0 24 High

Little Clatskanie River S5BCO001 8 2 3 1 3 3 0 20 Moderate

Milton Creek S3BCO010 8 4 1 1 1 3 0 18 Moderate

Milton Creek S3BCO001 5 5 1 5 3 3 0 22 High

Merrill Creek S3BCO017 8 3 5 1 1 2 0 20 Moderate

Tributary of Merrill Creek S3BCO122 8 4 3 5 1 2 0 23 High

Deer Island Slough S99CO011 0 0 0 5 1 3 3 12 Low

ID = identification.

Limitations 

This memorandum has been prepared for the exclusive use of LNG Development Company, LLC, and the

Oregon Pipeline Company, LLC, and CH2M HILL, for application to the specific stream crossings described

along the Oregon Pipeline Project in Clatsop and Columbia counties, Oregon. It has been prepared in

accordance with generally accepted geotechnical engineering practice. No other warranty, express or

implied, is made.

The geologic information contained in this memorandum is from published geology and geologic hazard

maps. Data related to ground surface topography are from various sources that include in order of

decreasing accuracy and detail, field surveys, aerial photography, and 1:24,000 USGS topographic maps.

Information on land use is based on aerial photographs available at the time of this assessment and

observations made during field reconnaissance of sites where access to stream crossings could be obtained.

The interpretations and recommendations contained in this memorandum are based on limited data and

should be considered preliminary. Site‐specific information for each Pipeline stream crossing should be

collected. CH2M HILL is not responsible for any claims, damages, or liability associated with interpretation of

subsurface data or for reuse of subsurface data, without CH2M HILL’s express written authorization.

References 

Beaulieu, John D. 1972a. Hazard Map of the Birkenfeld Quadrangle, Oregon. Oregon Department of Geology

and Mineral Industries. Bulletin 79. Map Scale 1:62,500.

Beaulieu, John D. 1972b. Hazard Map of the Saddle Mountain Quadrangle, Oregon. Oregon Department of

Geology and Mineral Industries. Bulletin 79. Map Scale 1:62,500.

Beaulieu, John D. 1973. “Environmental Geology of Inland Tillamook and Clatsop Counties.” Oregon

Department of Geology and Mineral Industries. Bulletin 79.
LANDSLIDE AND DEBRIS FLOW: RELATIVE RISK ASSESSMENT FOR THE BIDIRECTIONAL PROJECT PIPELINE 

18 

Benda, L.E. and T.W. Cundy. 1990. “Predicting Deposition of Debris Flows in Mountain Channels.” Canadian

Geotechnical Journal. Vol. 27, No. 4, pp. 409‐417.

Burns, W. J., and Madin, I. P. 2009. Protocol for Inventory Mapping of Landslide Deposits from Light

Detection and Ranging (LIDAR) Imagery. Oregon Department of Geology and Mineral Industries.

Special Paper 42.

CH2M HILL. 2009. Geologic Hazard: Slope Instability/Landslide Inventory Map. Prepared for Resource

Report 6. Prepared for Oregon LNG.

CH2M HILL. 2013. Geologic Hazard: Slope Instability/Landslide Inventory Map. Prepared for Resource

Report 6. Prepared for Oregon LNG. November.

Dietrich, W.E. and T. Dunne. 1978. “Sediment budget for a small catchment in mountainous terrain.”

Zeitschrift fur Geomorphologie. Bd. 29, pp. 191‐206.

Oregon Department of Geology and Mineral Industries (DOGAMI). 2009. Oregon Geologic Data Compilation

(OGDC) Release 5. OGDC‐5. Compiled by Lina Ma, Ian P. Madin, Keith V. Olson, and Rudie J. Watzig.

Hofmeister, R. Jon. 2000. Slope Failures in Oregon: GIS Inventory for Three 1996/97 Storm Events. Oregon

Department of Geology and Mineral Industries. Special Paper 34.

Hofmeister, R. Jon. 2002. Hazard Map of Potential Rapidly Moving Landslides in Western Oregon. Oregon

Department of Geology and Mineral Industries. Interpretive Map Series IMS‐22.

May, C.L. 1990. Debris Flow Characteristics Associated with Forest Practices in the Central Oregon Coast

Range. Oregon State University. Corvallis, Oregon. Master’s Thesis.

Millard, T. 1999. Debris Flow Initiation in Coastal British Columbia Gullies. British Columbia Forest Service.

Forest Research Technical Report TR‐002.

Niem, Alan R. and Wendy A. Niem. 1985. Oil and Gas Investigation of the Astoria Basin, Clatsop and

Northernmost Tillamook Counties, Northwest Oregon. Oregon Department of Geology and Mineral

Industries, Oil and Gas Investigations 14. Map Scale 1:100,000.

Orr, Elizabeth L., William N. Orr, and Ewart Baldwin. 1992. Geology of Oregon. Kendall/Hunt Publishing

Company. Dubuque, Iowa.

Reneau, S.L. and W.E. Dietrich. 1987. The Importance of Hollows in Debris Flow Studies. Examples from

Marin County, California, in Costa, J.E., and Wieczorek, G.F., eds., Debris Flows/Avalanches. Process,

Recognition, and Mitigation. Geological Society of America Reviews in Engineering Geology VII.

Robison, E.G., K. Mills, J. Paul, L. Dent, L., and A. Skaugset. 1999. Storm Impacts and Landslides of 1996. Final

Report. Oregon Department of Forestry Forest Practices Technical Report 4.

Rosgen, Dave. 1996. Applied River Morphology. Copyright 1996 by Wildland Hydrology, Pagosa Springs,

Colorado.

Tsukamoto, Y., T. Ohta, and H. Noguchi. 1982. “Hydrological and geomorphological studies of debris slides

on forested hillslopes in Japan, in recent developments in the explanation of prediction of erosion

and sediment yield.” Proceedings of the Exeter Symposium. July 1982. pp. 89‐98.

Varnes, D.J. 1978. Slope‐Movement Types and Processes. Special Report 176: “Landslides: Analysis and

Control” (R.L. Schuster and R.J. Krizek, eds.). Transportation Research Board, National Research

Council, Washington D.C., pp. 11‐33.

Washington Department of Natural Resources (WDNR). 1994. Board Manual: Standard Methodology for

Conducting Watershed Analysis Under Chapter 222‐22 WAC. Washington Department of Natural

Resources, Olympia, Washington.  
Attachment 

Landslide Inventory and Geologic Hazard Maps 
 
APPENDIX H 

OTHER SPECIAL STATUS SPECIES FOR OREGON LNG PROJECT

H-1 

Table H-1 

Other Special Status Species for Oregon LNG Project

Species a Status b Habitat Impacts MiPlants Bradshaw’s desert parsley Lomatium bradshawii

F-E OR-E OCS WA-E 

Range extends from western Washington south through the Willamette Valley. Historically found in lowland Deschampsia cespitosa prairies with heavy clay soils; especially Bashaw soils. Also in wetland depressions, grassy swales, and along seasonally wet waterways and flooded prairie lowlands. Unlikely to occur in project area. Associated plant species include Deschampsia caespitosa, Juncus tenuis, Carex stipata, Carex uniLateralis, Poa pratensis, Hordeum brachyantherum, Perideridia sp., Juncus sp. 

If present in the right-of-way, these plants would be disturbed and potentially lost to vegetation clearing and ground disturbing activities. However, most of the pipeline would be routed through previously disturbed industrial forest or agricultural areas that likely preclude these plant species. 

ForignatwitLNseeProA bconremrar

Wayside aster Eucephalus vialis OR-T OCS Many of the 100 known populations occur in disturbed areas (ODFW, 2006). Found in second growth and old-growth Douglas fir forests, mixed coniferous/hardwood forest openings, along shaded 

roadsides, in residential areas, and on prairie balds. 

White rock larkspur Delphinium leucophaeum

OR-E OCS WA-E 

Only 17 known occurrences in Oregon (OSU, 2008). Historically occurred in upland prairies. Due to habitat loss, species is found in 

remnant habitat patches, along dry roadsides, dry roadside ditches, 

open fields, dry hillsides, meadow and grassland. Also, some occurrences on the edge of oak woodlands. 

Invertebrates Haddock’s rhyacophilan caddisfly Rhyacophila haddocki

F-SOC OCS 

Requires cool, clear streams with coarse sediment and little silt. Waterbody crossings would temporary disturb 

substrate and cause turbidity that could inhibit the growth and survival of aquatic insects. Following construction, stream substrate is expected to return to preconstruction conditions. 

OrcerdisCoProop

Roth’s blind ground beetle Pterostichus rothi

F-SOC OCS 

Requires cool, moist, closed-canopy conifer forests with deep, welldrained soils. Lives within soil but requires coarse woody debris for refugia. 

Pipeline construction in conifer forests may result in the loss of ground dwelling insects. 

OravopoClepreWhwo

Willamette floater (freshwater mussel) Anodonta wahlametensis

OCS WA-SC 

Occurs in lakes, slow-moving rivers, streams and sloughs. Substrate is either mud or sand. Uses waters with low gradient, 

especially waterways in coastal areas. As with most mussels, this species requires specific species of native fish to fulfill portions of its larval life history. 

In-water excavation and dewatering associated with waterbody crossings could result in the loss of freshwater mussels if they are present in the substrate. Following construction, stream substrate is expected to return to preconstruction conditions. 

Orcerimpcroaqwh
H-2 

Table H-1 

Other Special Status Species for Oregon LNG Project

Species a Status b Habitat Impacts MiFish Pacific lamprey Entosphenus tridentatus 

F-SOC OR-SV OCS 

Feed and grow in the ocean, then return to freshwater rivers for spawning and early development. Requires fine gravel beds for 

spawning and cool clean water for development within river systems. 

In-water excavation and dewatering associated with waterbody crossings could result in the loss of lamprey if they are present in the substrate. Following construction stream substrate is expected to return to preconstruction conditions. 

OrcerbeOrspeincCoBabalam

River lamprey Lampetra ayresii 

F-SOC WA-C 

Riffle and side channel habitats are important for spawning and for 

ammocoete rearing. Lamprey ammocoetes colonize areas with soft substrate and good water quality. Adults feed in nearshore marine and estuarine habitat. 

Waterbody crossings in Cowlitz County may support river lamprey. In-water excavation and dewatering associated with waterbody crossings could result in the loss of ammocoetes buried in the sediment. Following construction stream substrate is expected to return to preconstruction conditions. 

At saldewto t

Coastal cutthroat Oncorhynchus clarki clarki 

F-SOC OR-SV 

Utilize a wide variety of habitat types during their complex life cycle. Spawn in small tributary streams and utilize slow flowing backwater areas, low velocity pools, and side channels for rearing of young. Large woody debris, instream structures and vegetation are important for protection while in freshwater. Clean gravel is needed 

for spawning and rearing. 

Coastal cutthroat are documented as occurring in 10 streams to be crossed by the project, although their presence is assumed in all other fish bearing streams that would be crossed. Waterbody crossings would temporarily displace cutthroat due to inwater work and increased turbidity. Direct mortality may occur if fish are trapped in the dewatered area at open cut crossings. 

OrwaimpcropreCoBabacutErotur

Amphibians and Reptiles Western toad Bufo boreas

WA-C Found in a variety of habitats, including slow moving rivers and 

streams; wetlands; near ponds and lakes; and in woodlands, grasslands and forests. Elevation range extends from sea level to above the tree-line. Main factor for selecting habitat is proximity to 

water for breeding. Requires sun exposed shallows with little to no vegetation for egg laying and tadpole rearing habitat. Unlikely to occur in project area. 

Waterbody and wetland crossings could temporarily displace or result in the mortality of toads and frogs. Following construction stream and riparian habitat is expected to return to preconstruction conditions. 

ThwapoavopreOrwaimpAt salamWh

Coastal tailed frog Ascaphus truei

OR-SV OCS 

Limited to cold, clear, fast-flowing streams that contain water year round; typically in conifer forests, but some populations have been found in non-forested streams. Adults require small boulders in the stream channel for egg laying. Larvae require moss free rocks, which they attach themselves to in well-oxygenated stream sections. 
H-3 

Table H-1 

Other Special Status Species for Oregon LNG Project

Species a Status b Habitat Impacts MiRed-legged frog Rana aurora

OCS OR-SV 

Undisturbed, continuously watered streams with shallow pools and emergent vegetation. Also found in marshes, wet meadows and occasionally ponds and ephemeral pools. Selects sites that provide access to forested areas. 

left Erotur

Foothill yellowlegged frog Rana boylii 

F-SOC OCS OR-SC OR-SV 

Found in permanently watered, slow-flowing streams and backwaters and in coniferous and deciduous forests and woodlands. Streams typically have rocky substrate, sloping banks and vegetation on the stream bank. 

Columbia torrent salamander Rhyacotriton kezeri

OR-SV OCS 

Range extends from the Chehalis River in Grays Harbor County, Washington, south to the Little Nestucca River, in Tillamook County, Oregon. Both adults and larvae live beneath or close to mosscovered rocks. Found in streams that are perennial, have loose gravel, and are located in steep, mountainous areas within coniferous forests where the banks are heavily vegetated and shaded. Headwater streams, springs, and seeps are often used. 

Construction in or near waterbodies and wetlands could result in the temporary displacement or loss of salamanders. Following construction, stream and riparian habitat is expected to return to preconstruction conditions. 

OrwaimpAt salamWhleft Erotur

Clouded salamander Aneides farreus

OR-SV OCS 

Found in forested habitats. Inhabits moist areas within conifer forests in the Coastal Range. Often found beneath downed logs and vegetation. Also commonly found in recently burned and cleared areas, as long as large logs are left behind. Strongly associated with Douglas-fir logs. 

Southern torrent salamander Rhyacotriton variegatus 

F-SOC OR-SV OCS 

Range extends from the Little Nestucca River in Tillamook County, Oregon, south to Mendocino County, California. Occurs in permanently flowing, steep, mountainous streams in moist, conifer 

forests. Utilizes shallow sections of streams, including splash zones and riffles. Requires loose gravel substrate, as larvae rear in cobble and gravel beds that receive stream flow. 

Western painted turtle Chrysemys picta bellii

OR-SC OCS 

Inhabits marshy ponds, small lakes and backwaters of rivers and slowing moving streams. Often selects waterways with mud substrate and emergent vegetation. Requires logs, large rocks, or vegetation mats for basking, and bare patches of ground close to water to lay eggs. Possibly occurs in project area. 

Oregon LNG would generally avoid ponds, lakes, or large wetlands with standing water. Therefore, the potential for impacts on turtles is low. However, turtles could be temporary displaced or lost if they are present at waterbody or wetlands crossings. 

OrwaimpAt salfroWhleft 

Birds 

American bald eagle Haliaeetus leucocephalus 

F-SOC OCS OR-SV WA-S 

Associated with large waterbodies that support fish populations 

including rivers, lakes, and the ocean. Area must have large trees that provide nesting structure. They also require variable wintering habitats that support a varied food web. 

Eagles forage along the Columbia River and Youngs Bay near the terminal, but the terminal site does not contain suitable habitat structure for eagles. There are four known eagle nests within 0.5 miles of the pipeline. Construction noise may disturb eagles. 

OrtreactbreOrnepla
H-4 

Table H-1 

Other Special Status Species for Oregon LNG Project

Species a Status b Habitat Impacts MiLittle willow flycatcher Empidonax traillii brewsteri

F-SOC OR-SV OCS 

Inhabits scrub-shrub patches of vegetation adjacent to water for nesting and foraging. 

Wetland crossings may temporarily disturb scrub shrub wetland habitat, but vegetation is expected to recover following construction. 

Orbe

Mammals 

California myotis Myotis californicus

OR-SV OCS 

Inhabits a mixture of forest types using large snags for day roosts. 

Often found night roosting under bridges. 

The pipeline would avoid caves, cliffs, and bridges that could be used by bats as roosting sites. The pipeline would also avoid late successional confer forest by crossing industrial forest or agricultural lands to the extent possible. Timber clearing within the right-of-way could reduce available roosting sites for bats. 

WhconOrthe for

Fringed myotis Myotis thysanodes 

F-SOC OR-SV OCS 

Inhabits a mixture of forest types using large snags for day roosts. 

Requires large snags and rock features for day, night, and maternity roosts (occasionally uses bridges). Caves and old mines are often used for hibernacula. 

Hoary bat Lasiurus cinereus 

OR-SV OCS 

Inhabits a mixture of forest habitats but is often associated with late successional forests for roosting. 

Long legged myotis Myotis volans

F-SOC OR-SV OCS 

Often associated with late successional conifer forests or other forested habitat with late successional components. Uses large snags and hollows of trees primarily in riparian zones for day, night, and maternity roosts. Occasionally found in caves and old mines. Forages in forest riparian and forest edge areas. 

Silver haired bat Lasionycteris noctivagans 

F-SOC OR-SV OCS 

Inhabits late-successional conifer forests where it uses large snags 

and hollows in trees for day, night, and maternity roosting. Is migratory in nature. 

Townsend’s bigeared bat Corynorhinus townsendii 

F-SOC WA-SC OR-SC OCS 

Inhabits caves, mines, and old buildings for day, night, and maternity roosts or hibernacula. Occasionally uses hollows in trees or bridges 

for day and night roosting. Primarily feeds on moths. 

American marten Martes americana 

OR-SV OCS 

Inhabits forest habitats with high density of snags and fallen logs for 

den sites and foraging. Often associated with late-successional mixed conifer habitats with multi-layer stands. 

Timber clearing would reduce the quantity and quality of forest habitat. Small mammals may be temporarily or permanently displaced due to the loss of habitat. However, the pipeline would not cross large tracts of old forest that is preferred by American marten and red tree vole, so there would be low likelihood of encountering these species. 

ThconinsanminmasucWhremthe Orthe forred 

Red tree vole Arborimus longicaudus 

F-C OR-SV OCS 

Found in dense, moist conifer forests. Prefers large stand size. Has a highly specialized diet of Douglas-fir needles. Nest at least 50 feet above ground level in highly developed conifers. 

__________

a Special status species that are also federally listed are addressed in section 4.1.8; OCS species that are not likely to occur in the project area are excluded. b OCS = Oregon Conservation Strategy species; OR-SV = ODFW Sensitive Vulnerable; OR-SC = ODFW Sensitive Critical; WA-E = Washington Endangered; WA

Washington Sensitive; F-E = Federal Endangered Species; F-C = Federal Candidate Species; F-SOC = Federal Species of Concern 
APPENDIX I 

WEP FACILITY MAPS, DRAWINGS, AND TABLES

Appendix I1: WEP Facility Location Maps 

Appendix I2: Pipeline Construction Right-of-way Cross Sections and Configuration Table 

Appendix I3: Pipeline Route Minor Variations 

Appendix I4: Additional Temporary Workspace for the Pipeline Route 

Appendix I5: Table of Access Roads 

Appendix I6: Site-specific Residential Construction Plans; Table of Residences within 50 Feet of WEP 

Construction Right-of-way and ATWS; Site-specific School Construction Plans 

Appendix I7: Utilities Crossed 

Appendix I8: Major Roads and Railroads Crossed 

APPENDIX I1 

WEP FACILITY LOCATION MAPS 

Battle Ground District Office Yard 3.54 Acres

NE 219Th St

Source: Esri, DigitalGlobe, GeoEye, i-cubed, USDA, USGS, AEX, Getmapping,

Aerogrid, IGN, IGP, and the GIS User Community

DRAWING

NUMBER:

WASHINGTON EXPANSION 

PROJECT

DRAWN BY:

CHECKED BY:

APPROVED BY:

DATE:

DATE:

DATE:

ISSUED FOR BID:

ISSUED FOR CONSTRUCTION:

SCALE: 1"=1000'

SHEET

OF

DRAWING NO. TITLE

REFERENCE DRAWINGS

REVISIONS

NO. DATE BY DESCRIPTION W.O. NO. CHK. APP.

Pipe Yard Locations

5/17/2013

t

CLARK COUNTY

T3N, R2E, Sec. 5

Figure 1.1 - 17

MC

01 5/15/2013 MC
Fredrickson Pipe Yard 13.87 Acres 38Th Ave E

 192Nd St E

Source: Esri, DigitalGlobe, GeoEye, i-cubed, USDA, USGS, AEX, Getmapping,

Aerogrid, IGN, IGP, and the GIS User Community

DRAWING

NUMBER:

WASHINGTON EXPANSION 

PROJECT

DRAWN BY:

CHECKED BY:

APPROVED BY:

DATE:

DATE:

DATE:

ISSUED FOR BID:

ISSUED FOR CONSTRUCTION:

SCALE: 1"=1000'

SHEET

OF

DRAWING NO. TITLE

REFERENCE DRAWINGS

REVISIONS

NO. DATE BY DESCRIPTION W.O. NO. CHK. APP.

Pipe Yard Locations

5/17/2013

t

PIERCE COUNTY

T19N, R3E, Sec 36

Figure 1.1 - 18

MC

01 5/15/2013 MC
Redmond District Office Yard 3.04 Acres

NE Redmond Fall City Rd 

Source: Esri, DigitalGlobe, GeoEye, i-cubed, USDA, USGS, AEX, Getmapping,

Aerogrid, IGN, IGP, and the GIS User Community

DRAWING

NUMBER:

WASHINGTON EXPANSION 

PROJECT

DRAWN BY:

CHECKED BY:

APPROVED BY:

DATE:

DATE:

DATE:

ISSUED FOR BID:

ISSUED FOR CONSTRUCTION:

SCALE: 1"=1000'

SHEET

OF

DRAWING NO. TITLE

REFERENCE DRAWINGS

REVISIONS

NO. DATE BY DESCRIPTION W.O. NO. CHK. APP.

Pipe Yard Locations

5/17/2013

t

KING COUNTY

T25N, R6E, Sec. 22

Figure 1.1 - 19

MC

01 5/15/2013 MC
Sumas Pipe Yard 11.81 Acres Bob Mitchell Ave

Sumas Pipe Yard 11.81 Acres Bob Mitchell Ave

Source: Esri, DigitalGlobe, GeoEye, i-cubed, USDA, USGS, AEX, Getmapping,

Aerogrid, IGN, IGP, and the GIS User Community

DRAWING

NUMBER:

WASHINGTON EXPANSION 

PROJECT

DRAWN BY:

CHECKED BY:

APPROVED BY:

DATE:

DATE:

DATE:

ISSUED FOR BID:

ISSUED FOR CONSTRUCTION:

SCALE: 1"=1000'

SHEET

OF

DRAWING NO. TITLE

REFERENCE DRAWINGS

REVISIONS

NO. DATE BY DESCRIPTION W.O. NO. CHK. APP.

Pipe Yard Locations

5/17/2013

t

WHATCOM COUNTY

T41N, R4E, Sec. 34

Figure 1.1 - 20

MC

01 5/15/2013 MC
D D

D

D 

104 100.1

HYDROSTATIC

SOURCE

PROPOSED 36" MLV

AND LAUNCHER/RECEIVER

(OREGON PIPELINE TIE-IN)

1244.29

PROPOSED 36" MLV

HYDROSTATIC TEST BREAK

AND DISCHARGE

STATE HWY. 503

INTERSTATE 5

101.1

100 103.1

101

106

10

102

103

105 100.2 

1245

1246

1247

1248

6N 1E

Woodland

Source: Esri, DigitalGlobe, GeoEye, i-cubed, USDA, USGS, AEX, G

NOTES:

DRAWN BY: 

0 2 1,000 ,000 4,000

Feet

P

WO

Sources: Esri, DeLorme,NAVTEQ, USGS, NRCAN,METI, iPC, TomTom

DATE:

CHECKED BY: DATE

APPROVED BY:

MC 5/6

MD

Legend

New Pipeline Segment

D Mileposts

Existing Access RoadTemporary Construction ROWTemporary Extra Work SpaceTownship & Range LineCities 
D

D

D

D

D

KALAMA RIVER

(HYDROSTATIC SOURCE 

AND DISCHARGE)

KALAMA RIVER

110

111

114 112

115.1

11

116.1

112.1

111.1

110 113

115 111

1252

1253

1251 1250

1254

7N 1W

Source: Esri, DigitalGlobe, GeoEye, i-cubed, USDA, USGS, AEX, G

NOTES:

DRAWN BY: 

0 2 1,000 ,000 4,000

Feet

PR

WO

Sources: Esri, DeLorme,NAVTEQ, USGS, NRCAN,METI, iPC, TomTom

DATE:

CHECKED BY: DATE

APPROVED BY:

MC 5/6

MD

Legend

New Pipeline Segment

D Mileposts

Existing Access RoadTemporary Construction ROWTemporary Extra Work SpaceTownship & Range LineCities 
D

D

D

D

D

121.1 122

122.1

COWEEMA(HYDROSTAND DISC

INTERSTATE 5

121

121

119

117

118

120

1256

1257 1258

1259

1260 

7N 1W

Carrolls

Rose Valley

Vision Acres

Source: Esri, DigitalGlobe, GeoEye, i-cubed, USDA, USGS, AEX, G

NOTES:

DRAWN BY: 

0 2 1,000 ,000 4,000

Feet

P

WO

Sources: Esri, DeLorme,NAVTEQ, USGS, NRCAN,METI, iPC, TomTom

DATE:

CHECKED BY: DATE

APPROVED BY:

MC 5/6

MD

Legend

New Pipeline Segment

D Mileposts

Existing Access RoadTemporary Construction ROWTemporary Extra Work SpaceTownship & Range LineCities 
D

D

D

D

D

123

127

127.1

128

PROPOSED 36" MLV

INTERSTATE 5

STATE HWY. 411

127.2

125 124

125.1

126

126.1

1266 1263 1262

1265

1264

8N 2W

Lexington

Source: Esri, DigitalGlobe, GeoEye, i-cubed, USDA, USGS, AEX, G

NOTES:

DRAWN BY: 

0 2 1,000 ,000 4,000

Feet

P

WO

Sources: Esri, DeLorme,NAVTEQ, USGS, NRCAN,METI, iPC, TomTom

DATE:

CHECKED BY: DATE

APPROVED BY:

MC 5/6

MD

Legend

New Pipeline Segment

D Mileposts

Existing Access RoadTemporary Construction ROWTemporary Extra Work SpaceTownship & Range LineCities 
DD

D

D

D

PROPOSED 36" MLV

INTERSTATE 5

STATE HWY. 411

COWLITZ RIVER STATE HWY. 504

134.4

134

133

134.2

129

130

134.3 

131 

132 134.1 

1272 1271 1269 1270 1268

Castle Rock High School

9N 2W

Silver Lake

Castle Rock

Source: Esri, DigitalGlobe, GeoEye, i-cubed, USDA, USGS, AEX, G

NOTES:

DRAWN BY: 

0 2 1,000 ,000 4,000

Feet

PR

WOO

Sources: Esri, DeLorme,NAVTEQ, USGS, NRCAN,METI, iPC, TomTom

DATE:

CHECKED BY: DATE

APPROVED BY:

MC 5/6

MD

Legend

New Pipeline Segment

D Mileposts

Existing Access RoadTemporary Construction ROWTemporary Extra Work SpaceTownship & Range LineCities 
D

D

D

D

D

D

136.2

136.3

TOUTLE RIVER(HYDROSTATIC SOURCEAND DISCHARGE)

INTERSTATE 5

TOUTLE RIVER

138

137

137.2

137 

13

138.1

137.3

137.1

138.2

136.1

137

137

137.4

137.5

1274

1275

1277

1276

1278

Source: Esri, DigitalGlobe, GeoEye, i-cubed, USDA, USGS, AEX, G

NOTES:

DRAWN BY: 

0 2 1,000 ,000 4,000

Feet

PR

WOO

Sources: Esri, DeLorme,NAVTEQ, USGS, NRCAN,METI, iPC, TomTom

DATE:

CHECKED BY: DATE

APPROVED BY:

MC 5/6

MD

Legend

New Pipeline Segment

D Mileposts

Existing Access RoadTemporary Construction ROWTemporary Extra Work SpaceTownship & Range LineCities 
D

D

D

D D

PROPOSED 36" MLV

HDD ENTRY

COWLITZ RIVER(HYDROSTATIC SOURCEAND DISCHARGE)

HDD EXIT

INTERSTATE 5

S

TAT

E

H

W

Y.

5

0

5

141

139

141.1

142

141

140

141.2 

1284

1283

1281 1282 1280

11N 2W

Toledo

Source: Esri, DigitalGlobe, GeoEye, i-cubed, USDA, USGS, AEX, G

NOTES:

DRAWN BY: 

0 2 1,000 ,000 4,000

Feet

P

WO

Sources: Esri, DeLorme,NAVTEQ, USGS, NRCAN,METI, iPC, TomTom

DATE:

CHECKED BY: DATE

APPROVED BY:

MC 5/6

MD

Legend

New Pipeline Segment

D Mileposts

Existing Access RoadTemporary Construction ROWTemporary Extra Work SpaceTownship & Range LineCities 
DD DD

147

PROPOSED 36" MLVAND LAUNCHER/RECEIVER

CHEHALIS COMPRESSORSTATION

INTERSTATE 5

U

.

S.

H

WY

1

2

148

144

146

145

1289 1288

1287

1286

12N 2W

Source: Esri, DigitalGlobe, GeoEye, i-cubed, USDA, USGS, AEX, G

NOTES:

DRAWN BY: 

0 2 1,000 ,000 4,000

Feet

P

WO

Sources: Esri, DeLorme,NAVTEQ, USGS, NRCAN,METI, iPC, TomTom

DATE:

CHECKED BY: DATE

APPROVED BY:

MC 5/6

MD

Legend

New Pipeline Segment

D Mileposts

Existing Access RoadTemporary Construction ROWTemporary Extra Work SpaceTownship & Range LineCities 
D D

D

D

200

203

PROPOSED 36" MLVAND LAUNCHER/RECEIVER

HDD ENTRY HDD EXIT

NEWAUKUM RIVER(HYDROSTATIC SOURCEAND DISCHARGE)

INTERSTATE 5

204

201

207

202 206 205

Newaukum Valley Golf Course

13N 2W

13N 1W

12N 2W

12N 1W

1292

1293

1295 1294

Source: Esri, DigitalGlobe, GeoEye, i-cubed, USDA, USGS, AEX, G

NOTES:

DRAWN BY: 

0 2 1,000 ,000 4,000

Feet

PR

CHE

LE

Sources: Esri, DeLorme,NAVTEQ, USGS, NRCAN,METI, iPC, TomTom

DATE:

CHECKED BY: DATE

APPROVED BY:

MC 5/6

MD

Legend

New Pipeline Segment

D Mileposts

Existing Access RoadTemporary Construction ROWTemporary Extra Work SpaceTownship & Range LineCities 
D

D

D

D

D

211 211.1

214.1

212

212.1

212.2

210

214

214

213

209

14N 1W

14N 2W

13N 1W

13N 2W

1302

1299

1298

1300

1301

Source: Esri, DigitalGlobe, GeoEye, i-cubed, USDA, USGS, AEX, G

NOTES:

DRAWN BY: 

0 2 1,000 ,000 4,000

Feet

P

C

Sources: Esri, DeLorme,NAVTEQ, USGS, NRCAN,METI, iPC, TomTom

DATE:

CHECKED BY: DATE

APPROVED BY:

MC 5/6

MD

Legend

New Pipeline Segment

D Mileposts

Existing Access RoadTemporary Construction ROWTemporary Extra Work SpaceTownship & Range LineCities 
D

D D

D D

216

218.2

218.3

21

218

216

218.1

216.2

215

216.1

217

14N 1W

1304

1305

1306

1307

1308

Source: Esri, DigitalGlobe, GeoEye, i-cubed, USDA, USGS, AEX, G

NOTES:

DRAWN BY: 

0 2 1,000 ,000 4,000

Feet

PR

CH

L

Sources: Esri, DeLorme,NAVTEQ, USGS, NRCAN,METI, iPC, TomTom

DATE:

CHECKED BY: DATE

APPROVED BY:

MC 5/6

MD

Legend

New Pipeline Segment

D Mileposts

Existing Access RoadTemporary Construction ROWTemporary Extra Work SpaceTownship & Range LineCities 
D D

D

D

D

219

222

PROPOSED 36" MLV

221 221 221.4

220

221

221.1

221 223

221.2

221

221.3 223

16N 1E

16N 1W

1310

1312

1311

1313

1314

Source: Esri, DigitalGlobe, GeoEye, i-cubed, USDA, USGS, AEX, G

NOTES:

DRAWN BY: 

0 2 1,000 ,000 4,000

Feet

PR

CH

L

Sources: Esri, DeLorme,NAVTEQ, USGS, NRCAN,METI, iPC, TomTom

DATE:

CHECKED BY: DATE

APPROVED BY:

MC 5/6

MD

Legend

New Pipeline Segment

D Mileposts

Existing Access RoadTemporary Construction ROWTemporary Extra Work SpaceTownship & Range LineCities 
D D D

D D

302.2 303

EXISTING 36" MLV

(REMOVE LAUNCHER/RECEIVER)

302.1

304 301

302 300

19N 4E

19N 3E18N 4E

18N 3E

South Hill

Frederickson

Stahl Junior High School

Brouillet Elementary School

Pioneer Valley Elementary SCH

1338

1339

1340

1342

1341

Source: Esri, DigitalGlobe, GeoEye, i-cubed, USDA, USGS, AEX, G

NOTES:

DRAWN BY: 

0 2 1,000 ,000 4,000

Feet

WAS

SU

Sources: Esri, DeLorme,NAVTEQ, USGS, NRCAN,METI, iPC, TomTom

DATE:

CHECKED BY: DATE

APPROVED BY:

Cities 

MC 5/6

MD

Legend

New Pipeline Segement

D Mileposts

Exitsting Access RoadTemporary Construction ROWTemporary Extra Work SpaceTownship & Range Line
D

D

D

D D

306

PROPOSED 36" MLV

PROPOSED 36" MLV

H

PUYALLUP RIVER(HYDROSTATIC SOURCEAND DISCHARGE)

STATE HWY. 512

STATE HWY. 161

STATE HWY. 161

307

308

310

309

19N 4E

19N 5E

Puyallup

Alderton

South Hill Mall

Pierce College

Linden Golf Course and Coun

Woodbine Cemetery 

Ballou Junior High School

Ferrucci Junior High School

Cascade Christian Jr and Sr HS

Meridian Place Shopping Center Shaw Road Elementary School

Sunrise Elementary School

McAlder Elementary School

Ridgecrest Elementary School

Good Samaritan Community Hospital

Firgrove Elementary School

Wildwood Park Elementary SCH

Spinning Elementary School

Puyallup Cascade Christian SCH

1343 1344

1345 1347

1346

Source: Esri, DigitalGlobe, GeoEye, i-cubed, USDA, USGS, AEX, G

NOTES:

DRAWN BY: 

0 2 1,000 ,000 4,000

Feet

WA

S

Sources: Esri, DeLorme,NAVTEQ, USGS, NRCAN,METI, iPC, TomTom

DATE:

CHECKED BY: DATE

APPROVED BY:

Cities 

MC 5/6

MD

Legend

New Pipeline Segement

D Mileposts

Exitsting Access RoadTemporary Construction ROWTemporary Extra Work SpaceTownship & Range Line
D

D

314

EXISTING 36" MLV

(REMOVE LAUNCHER/RECEIVER)

SUMNER COMPRESSOR STATION

STATE HWY.

410

Lakeridge Junior High School

Sumner High School

Crestwood Elementary School

North Tapps Elementary Sch

Tapps Island Golf Course

Lake Tapps Elementary School

Tapps Island Golf Course

Tapps Island Golf Course

Tapps Island Golf Course

Tapps Island Golf Course

Tapps Island Golf Course

1350

1351

Source: Esri, DigitalGlobe, GeoEye, i-cubed, USDA, USGS, AEX, G

NOTES:

DRAWN BY: 

0 2 1,000 ,000 4,000

Feet

WAS

SU

Sources: Esri, DeLorme,NAVTEQ, USGS, NRCAN,METI, iPC, TomTom

DATE:

CHECKED BY: DATE

APPROVED BY:

Cities 

MC 5/6

MD

Legend

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D Mileposts

Exitsting Access RoadTemporary Construction ROWTemporary Extra Work SpaceTownship & Range Line
D D

D

D

402

404 

405

401

STATE HWY. 18

GREEN RIVER(HYDROSTATIC SOURCEAND DISCHARGE)

400

407 406 

21N 5E

Washington National Golf Club

Jade Greens Golf Course

Auburn Adventist Academy

Lakeview Elementary School

Chinook Elementary School

Buena Vista Sda Elementary SCH

Green River Community College

Lake Morton-Berrydale

1357

1359

1358 1360

Source: Esri, DigitalGlobe, GeoEye, i-cubed, USDA, USGS, AEX, G

NOTES:

DRAWN BY: 

0 2 1,000 ,000 4,000

Feet

WASH

SUMNE

K

Sources: Esri, DeLorme,NAVTEQ, USGS, NRCAN,METI, iPC, TomTom

DATE:

CHECKED BY: DATE

APPROVED BY:

Cities 

MC 5/6

MD

Legend

New Pipeline Segment

D Mileposts

Existing Access RoadTemporary Construction ROWTemporary Extra Work AreaTownship & Range Line
D

D

STATE HWY. 18

STAE

HWY.

516

STATE

HWY.

169

HYDROSTATIC SOURCE

AND DISCHARGE

413 412

22N 6E

21N 6E

22N 5E

Lake Wilderness Golf Course

Elk Run Golf Club

Druids Glenn Golf Course

Covington Square

Cedar Heights Junior High SCH

Lake Wilderness Elementary SCH

Jenkins Creek Elementary SCH

Cedar River Elementary School

Grass Lake Elementary School

Lake Wilderness Golf Course

Cedar Valley Elementary School

Covington Elementary School

Shadow Lake Elementary School

Kentlake High School

Covington

Maple Valley

Cherokee Bay Park

1363

1362

Source: Esri, DigitalGlobe, GeoEye, i-cubed, USDA, USGS, AEX, G

NOTES:

DRAWN BY: 

0 2 1,000 ,000 4,000

Feet

WASHIN

SUM

1363.9

Sources: Esri, DeLorme,NAVTEQ, USGS, NRCAN,METI, iPC, TomTom

DATE:

CHECKED BY: DATE

APPROVED BY:

Cities 

MC 5/6

MD

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D Mileposts

Existing Access RoadTemporary Construction ROWTemporary Extra Work AreaTownship & Range Line
D

D

D

D

D 507

508 502

EXISTING 36" MLV(REMOVE LAUNCHER/RECEIVER)

ISSAQUAH CREEK(HYDROSTATIC SOURCEAND DISCHARGE)

HYDROSTATIC TEST BREAKAND DISCHARGE

510 511 509 500 502.1

501

504 505

503

506

23N 6E

Issaquah Middle Scho

Issaquah High School

Clark Elementary School

Hillside Ce

1371

1373 

1372

1374

1375

Source: Esri, DigitalGlobe, GeoEye, i-cubed, USDA, USGS, AEX, G

NOTES:

DRAWN BY: 

0 2 1,000 ,000 4,000

Feet

WASHIN

SUM

1381.9

Sources: Esri, DeLorme,NAVTEQ, USGS, NRCAN,METI, iPC, TomTom

DATE:

CHECKED BY: DATE

APPROVED BY:

Cities 

MC 5/6

MD

Legend

New Pipeline Segment

D Mileposts

Existing Access RoadTemporary Construction ROWTemporary Extra Work Space
D

D

D

D

D

513

514

PROPOSED 36" MLV(EXISTING NORTH BEND/SNOQUALMIEMETER STATION)

515

24N 6E

Skyline High School

Lutheran Bible Institute

Klahanie Center

Pine Lake Village

The Commons at Issaquah

Pine Lake Middle School

Beaver Lake Middle School

Town & Country Square

Endeavour Elementary School

Sunnyhills Elementary School

Discovery Elementary School

Challenger Elementary School

Gilman Village 

Arbor Elementary School

1380

1378

1379

1377

Source: Esri, DigitalGlobe, GeoEye, i-cubed, USDA, USGS, AEX, G

NOTES:

DRAWN BY: 

0 2 1,000 ,000 4,000

Feet

WASHI

SUM

1381.

Sources: Esri, DeLorme,NAVTEQ, USGS, NRCAN,METI, iPC, TomTom

DATE:

CHECKED BY: DATE

APPROVED BY:

Cities 

MC 5/6

MD

Legend

New Pipeline Segment

D Mileposts

Existing Access RoadTemporary Construction ROWTemporary Extra Work Space
D

D

D

D

D D

SNOHOMISH COMPRESSOR STATION

PROPOSED 36" MLV AND RECEIVER

HDD EXIT SNOHOMISH RIVER (HYDROSTATIC SOURCE

AND DISCHARGE)

HDD ENTRY

PROPOSED 36" MLV

STATE

HWY.

522

603.1

603.1

603

600

602

601

The Golf Club at Echo Falls

Echo Lake

1394

1397

139

1395

1396

Source: Esri, DigitalGlobe, GeoEye, i-cubed, USDA, USGS, AEX, G

NOTES:

DRAWN BY: 

0 2 1,000 ,000 4,000

Feet

PR

SNO

Sources: Esri, DeLorme,NAVTEQ, USGS, NRCAN,METI, iPC, TomTom

DATE:

CHECKED BY: DATE

APPROVED BY:

MC 5/6

MD

Legend

New Pipeline Segement

D Mileposts

Existing Access RoadTemporary Construction ROWTemporary Extra Work AreaCities
D

D D D

U.S.

HWY.

2

605

604 608

607 606

28N 6E

Snohomish Golf Course

Lobo Country Club

Dutch Hill Elementary School

Roosevelt

1401 1404 1403

1402

Source: Esri, DigitalGlobe, GeoEye, i-cubed, USDA, USGS, AEX,

NOTES:

DRAWN BY: 

0 2 1,000 ,000 4,000

Feet

 EXPAN

SN

SN

Sources: Esri, DeLorme,NAVTEQ, USGS, NRCAN,METI, iPC, TomTom

DATE:

CHECKED BY: DATE

APPROVED BY:

MC 5/6

MD

Legend

New Pipeline Segement

D Mileposts

Existing Access RoadTemporary Construction ROWTemporary Extra Work AreaCities
D

D

D

D

PILCHUCK RIVER

(HYDROSTATIC SOURCE AND DISCHARGE)

EXISTING 36" MLV(REMOVE LAUNCHER/RECEIVER)

613 614

610

615

611612

29N 6E

28N 6E

Lak

North 

Mount Pilchuck Elementary 

Machias

Lake Stevens

1407

1406

1409

Source: Esri, DigitalGlobe, GeoEye, i-cubed, USDA, USGS, AEX, G

NOTES:

DRAWN BY: 

0 2 1,000 ,000 4,000

Feet

W

PRO

SNOH

Sources: Esri, DeLorme,NAVTEQ, USGS, NRCAN,METI, iPC, TomTom

DATE:

CHECKED BY: DATE

APPROVED BY:

MC 5/6

MD

Legend

New Pipeline Segement

D Mileposts

Existing Access RoadTemporary Construction ROWTemporary Extra Work AreaCities
D 

D

D

702

PROPOSED 36" MLV

AND LAUNCHER/RECEIVER

HYDROSTATIC

DISCHARGE

HYDOSTATIC SOURCE

AND DISCHARGE

STATE HWY. 9 

700

703.1

701

703

700

1436

1438

1437

Overlook

Golf Course

Montborne

34

33N 5E

Source: Esri, DigitalGlobe, GeoEye, i-cubed, USDA, USGS, AEX, G

NOTES:

DRAWN BY: 

0 2 1,000 ,000 4,000

Feet

WASHI

Mt. 

1440

SK

Sources: Esri, DeLorme,NAVTEQ, USGS, NRCAN,METI, iPC, TomTom

DATE:

CHECKED BY: DATE

APPROVED BY:

Existing Access RoadTemporary Construction ROW Temporary Extra Work Area Township & Range Line

Cities 

MC 5/6

MD

Legend

New Pipeline Segment

D Mileposts
D

D 

D

D

705

708

PROPOSED 36" MLV

AND LAUNCHER/RECEIVER

MT. VERNON COMPRESSOR STATION

PROPOSED 36" MLV

AND LAUNCHER/RECEIVER

EAST FORK OF NOOKACHAMPS RIVER

(HYDROSTATIC SOURCE AND DISCHARGE)

HYDROSTATIC TEST BREAK

AND DISCHARGE

(H

STATE HWY. 9

800

707

801 802 801.1 

706

1443

1442 

1440

1441

Clearlake

ClearLake

34N 4E

34N 5E

Source: Esri, DigitalGlobe, GeoEye, i-cubed, USDA, USGS, AEX, G

NOTES:

DRAWN BY: 

0 2 1,000 ,000 4,000

Feet

WASHIN

Mt. V

1440

SK

Sources: Esri, DeLorme,NAVTEQ, USGS, NRCAN,METI, iPC, TomTom

DATE:

CHECKED BY: DATE

APPROVED BY:

Existing Access RoadTemporary Construction ROW Temporary Extra Work Area Township & Range Line

Cities 

MC 5/6

MD

Legend

New Pipeline Segment

D Mileposts
D D D D

D

901 903

904 PROPOSED 36" MLV

EXISTING 36" MLV

(REMOVE LAUNCHER/RECEIVER)

STATE HWY. 9

904.1

902

9

900

37N 4E

Wickersham

1456

1457 1455 1458 1454

Source: Esri, DigitalGlobe, GeoEye, i-cubed, USDA, USGS, AEX, G

NOTES:

DRAWN BY: 

0 2 1,000 ,000 4,000

Feet

WAS

Mt. VERN

SKAGIT & 

Sources: Esri, DeLorme,NAVTEQ, USGS, NRCAN,METI, iPC, TomTom

DATE:

CHECKED BY: DATE

APPROVED BY:

Cities 

MC 5/6

MD

Legend

New Pipeline Segment

D Mileposts

Existing Access RoadTemporary Construction ROWTemporary Extra Work AreaTownship & Range Line
D

D

906

HDD EXIT

NOOKSACK RIVER

(HYDROSTATIC SOURCE AND DISCHARGE)

HDD ENTRY

EXISTING 36" MLV

(REMOVE LAUNCHER/RECEIVER)

STATE HWY. 9

3

37N 4E

38N 4E

Acme

Saxon

1460

1461

Source: Esri, DigitalGlobe, GeoEye, i-cubed, USDA, USGS, AEX, G

NOTES:

DRAWN BY: 

0 2 1,000 ,000 4,000

Feet

WA

Mt. VER

SKAGIT 

Sources: Esri, DeLorme,NAVTEQ, USGS, NRCAN,METI, iPC, TomTom

DATE:

CHECKED BY: DATE

APPROVED BY:

Cities 

MC 5/6

MD

Legend

New Pipeline Segment

D Mileposts

Existing Access RoadTemporary Construction ROWTemporary Extra Work AreaTownship & Range Line
D

D

D D

D

PROPOSED 36" MLV

AND LAUNCHER/RECEIVER

STATE HWY. 44

STATE HWY. 9

1001

1002

1000

1003

40N 4E

40N 5E

1483

1481 1482

1480

1479

Source: Esri, DigitalGlobe, GeoEye, i-cubed, USDA, USGS, AEX, G

NOTES:

DRAWN BY: 

0 2 1,000 ,000 4,000

Feet

PR

S

WH

Sources: Esri, DeLorme,NAVTEQ, USGS, NRCAN,METI, iPC, TomTom

DATE:

CHECKED BY: DATE

APPROVED BY:

Cities 

MC 5/6

MD

Legend

New Pipeline Segment

D Mileposts

Existing Access RoadTemporary Construction ROWTemporary Extra Work AreaTownship & Range Line

APPENDIX I2 

PIPELINE CONSTRUCTION RIGHT-OF-WAY CROSS SECTIONS 

AND CONFIGURATION TABLE

Appendix I2 

Pipeline Construction Right-of-way Cross Sections and Configuration Table 

 I2-1 

Milepost Start Milepost End ROW Typical a

Woodland Loop 

1244.29 1244.46 1 

1244.46 1244.48 2 

1244.48 1244.50 Nontypical 

1244.50 1244.50 2 

1244.50 1244.95 1 

1244.95 1244.96 Nontypical 

1244.96 1245.01 2 

1245.0 1245.64 1 

1245.64 1246.02 2 

1246.02 1246.06 1 

1246.06 1246.22 2 

1246.22 1246.22 Nontypical 

1246.22 1246.28 2 

1246.28 1246.73 1 

1246.73 1246.76 2 

1246.76 1247.42 1 

1247.42 1247.45 2 

1247.45 1247.63 1 

1247.63 1247.66 2 

1247.66 1247.73 1 

1247.73 1247.74 2 

1247.74 1248.30 1 

1248.30 1248.32 2 

1248.32 1248.45 1 

1248.45 1248.73 2 

1248.73 1248.75 1 

1248.75 1248.90 Nontypical 

1248.90 1248.97 1 

1248.97 1248.97 2 

1248.97 1251.32 1 

1251.32 1251.38 2 

1251.38 1253.44 1 

1253.44 1253.50 2 

1253.50 1253.52 1 

1253.52 1253.53 2 

1253.53 1255.30 1 

1255.30 1255.32 2 

1255.32 1255.74 1 

1255.74 1255.75 Nontypical 

1255.75 1256.41 1 

1256.41 1256.42 2 

1256.42 1256.90 1 

1256.90 1256.91 2 

1256.91 1256.93 1 

1256.93 1256.94 2 

1256.94 1256.95 Nontypical 

1256.95 1257.28 2 

1257.28 1257.47 1 

1257.47 1257.48 2 

1257.48 1257.52 1 

1257.52 1257.53 Nontypical 

1257.53 1257.59 1 

1257.59 1257.70 2 

1257.70 1257.74 1 

Milepost Start Milepost End ROW Typical a

1257.74 1257.75 Nontypical 

1257.75 1257.75 2 

1257.75 1257.77 1 

1257.77 1257.79 2 

1257.79 1258.02 1 

1258.02 1258.03 2 

1258.03 1258.05 Nontypical 

1258.05 1258.20 1 

1258.20 1258.37 2 

1258.37 1258.97 1 

1258.97 1259.00 2 

1259.00 1260.82 1 

1260.82 1260.83 2 

1260.83 1260.86 1 

1260.86 1260.88 2 

1260.88 1260.89 Nontypical 

1260.89 1260.92 2 

1260.92 1261.20 1 

1261.20 1261.21 2 

1261.21 1262.20 1 

1262.20 1262.59 Nontypical 

1262.59 1262.61 2 

1262.61 1263.12 1 

1263.12 1263.17 2 

1263.17 1263.19 1 

1263.19 1263.24 2 

1263.24 1263.25 Nontypical 

1263.25 1263.26 2 

1263.26 1265.25 1 

1265.25 1265.32 2 

1265.32 1269.06 1 

1269.06 1269.21 Nontypical 

1269.21 1269.54 1 

1269.54 1269.55 2 

1269.55 1274.00 1 

1274.00 1274.02 2 

1274.02 1274.22 1 

1274.22 1274.74 2 

1274.74 1275.67 1 

1275.67 1275.68 2 

1275.68 1275.77 1 

1275.77 1277.82 Nontypical 

1277.82 1278.16 1 

1278.16 1279.32 Nontypical 

1279.32 1279.71 1 

1279.71 1279.72 2 

1279.72 1280.15 1 

1280.15 1280.20 2 

1280.20 1280.21 Nontypical 

1280.21 1280.32 2 

1280.32 1280.34 1 

1280.34 1280.38 2 

1280.38 1280.48 1 

1280.48 1280.67 2 

1280.67 1280.76 1 
Appendix I2 

Pipeline Construction Right-of-way Cross Sections and Configuration Table 

 I2-2 

Milepost Start Milepost End ROW Typical a

1280.76 1280.82 2 

1280.82 1281.09 1 

1281.09 1281.13 2 

1281.13 1281.14 Nontypical 

1281.14 1281.14 2 

1281.14 1281.20 1 

1281.20 1281.20 2 

1281.20 1281.92 Nontypical 

1281.92 1282.03 2 

1282.03 1282.68 Nontypical 

1282.68 1282.87 1 

1282.87 1282.89 2 

1282.89 1282.92 1 

1282.92 1282.95 2 

1282.95 1283.12 1 

1283.12 1283.47 2 

1283.47 1284.03 1 

1284.03 1284.11 2 

1284.11 1284.25 1 

1284.25 1284.26 2 

1284.26 1284.74 1 

1284.74 1284.75 2 

1284.75 1284.92 1 

1284.92 1285.05 Nontypical 

1285.05 1285.43 1 

1285.43 1285.46 2 

1285.46 1285.79 1 

1285.79 1285.80 2 

1285.80 1286.17 1 

1286.17 1286.18 2 

1286.18 1286.77 1 

1286.77 1286.80 2 

1286.80 1286.88 1 

1286.88 1286.94 Nontypical 

1286.94 1287.33 1 

1287.33 1287.37 2 

1287.37 1287.72 1 

1287.72 1287.73 2 

1287.73 1288.10 1 

1288.10 1288.19 2 

1288.19 1288.27 1 

1288.27 1288.32 2 

1288.32 1288.87 1 

1288.87 1288.92 2 

1288.92 1289.03 1 

1289.03 1289.04 Nontypical 

1289.04 1289.54 1 

Chehalis Loop

1291.27 1291.40 1 

1291.40 1291.56 5 

1291.56 1291.59 Nontypical 

1291.59 1292.06 5 

1292.06 1292.28 1 

1292.28 1292.65 5 

1292.65 1293.14 1 

1293.14 1293.40 5 

Milepost Start Milepost End ROW Typical a

1293.40 1293.63 1 

1293.63 1293.89 5 

1293.89 1294.00 1 

1294.00 1294.30 Nontypical 

1294.30 1295.52 1 

1295.52 1295.56 2 

1295.56 1295.61 1 

1295.61 1295.61 Nontypical 

1295.61 1295.95 1 

1295.95 1295.98 2 

1295.98 1296.26 1 

1296.26 1296.30 2 

1296.30 1297.20 1 

1297.20 1297.21 Nontypical 

1297.21 1297.96 1 

1297.96 1297.98 2 

1297.98 1298.07 1 

1298.07 1298.15 2 

1298.15 1298.53 1 

1298.53 1298.68 Nontypical 

1298.68 1299.10 1 

1299.10 1299.17 2 

1299.17 1299.19 1 

1299.19 1299.70 Nontypical 

1299.70 1300.77 1 

1300.77 1300.78 2 

1300.78 1302.72 1 

1302.72 1302.75 2 

1302.75 1304.31 1 

1304.31 1306.17 Nontypical 

1306.17 1308.42 1 

1308.42 1309.80 Nontypical 

1309.80 1310.10 1 

1310.10 1311.88 Nontypical 

1311.88 1315.62 1 

Sumner South Loop

1338.00 1338.21 1 

1338.21 1338.33 2 

1338.33 1338.40 1 

1338.40 1338.46 2 

1338.46 1338.48 Nontypical 

1338.48 1338.51 2 

1338.51 1338.54 Nontypical 

1338.54 1338.56 2 

1338.56 1338.58 Nontypical 

1338.58 1338.60 2 

1338.60 1338.63 Nontypical 

1338.63 1338.66 2 

1338.66 1339.12 1 

1339.12 1339.24 Nontypical 

1339.24 1339.38 1 

1339.38 1339.38 Nontypical 

1339.38 1340.17 1 

1340.17 1340.46 2 

1340.46 1340.47 Nontypical 

1340.47 1340.59 2 
Appendix I2 

Pipeline Construction Right-of-way Cross Sections and Configuration Table 

 I2-3 

Milepost Start Milepost End ROW Typical a

1340.59 1340.64 1 

1340.64 1340.66 2 

1340.66 1340.67 Nontypical 

1340.67 1340.78 2 

1340.78 1340.79 Nontypical 

1340.79 1340.80 2 

1340.80 1340.80 Nontypical 

1340.80 1340.82 2 

1340.82 1340.82 Nontypical 

1340.82 1340.86 2 

1340.86 1340.86 Nontypical 

1340.86 1340.90 2 

1340.90 1340.90 Nontypical 

1340.90 1341.10 2 

1341.10 1341.13 1 

1341.13 1341.17 Nontypical 

1341.17 1341.19 2 

1341.19 1341.19 Nontypical 

1341.19 1341.21 1 

1341.21 1341.22 Nontypical 

1341.22 1341.38 2 

1341.38 1341.45 1 

1341.45 1341.46 Nontypical 

1341.46 1341.47 3 

1341.47 1341.48 Nontypical 

1341.48 1341.60 3 

1341.60 1341.60 Nontypical 

1341.60 1341.61 3 

1341.61 1341.62 Nontypical 

1341.62 1341.68 3 

1341.68 1341.69 Nontypical 

1341.69 1341.70 3 

1341.70 1341.71 Nontypical 

1341.71 1341.75 3 

1341.75 1341.77 Nontypical 

1341.77 1341.79 3 

1341.79 1341.84 Nontypical 

1341.84 1341.86 3 

1341.86 1341.86 2 

1341.86 1341.95 1 

1341.95 1342.06 2 

1342.06 1342.11 1 

1342.11 1342.13 Nontypical 

1342.13 1342.32 1 

1342.32 1342.35 2 

1342.35 1342.46 1 

1342.46 1342.47 2 

1342.47 1342.50 1 

1342.50 1342.50 Nontypical 

1342.50 1342.56 2 

1342.56 1342.56 Nontypical 

1342.56 1342.59 2 

1342.59 1342.83 1 

1342.83 1343.02 Nontypical 

1343.02 1343.12 1 

1343.12 1343.12 2 

Milepost Start Milepost End ROW Typical a

1343.12 1343.13 Nontypical 

1343.13 1343.14 2 

1343.14 1343.17 1 

1343.17 1343.21 Nontypical 

1343.21 1343.23 1 

1343.23 1343.26 Nontypical 

1343.26 1343.26 1 

1343.26 1343.29 Nontypical 

1343.29 1343.30 2 

1343.30 1343.31 1 

1343.31 1343.35 Nontypical 

1343.35 1343.35 3 

1343.35 1343.44 Nontypical 

1343.44 1343.46 1 

1343.46 1343.51 2 

1343.51 1343.52 1 

1343.52 1343.58 2 

1343.58 1343.59 Nontypical 

1343.59 1343.60 3 

1343.60 1343.62 Nontypical 

1343.62 1343.64 3 

1343.64 1343.65 Nontypical 

1343.65 1343.66 3 

1343.66 1343.70 Nontypical 

1343.70 1343.72 3 

1343.72 1343.79 Nontypical 

1343.79 1343.79 1 

1343.79 1344.18 Nontypical 

1344.18 1344.24 3 

1344.24 1344.25 Nontypical 

1344.25 1344.35 3 

1344.35 1344.36 2 

1344.36 1344.37 1 

1344.37 1344.38 Nontypical 

1344.38 1344.44 1 

1344.44 1344.45 Nontypical 

1344.45 1344.46 1 

1344.46 1344.53 2 

1344.53 1344.60 1 

1344.60 1344.61 Nontypical 

1344.61 1344.66 1 

1344.66 1344.67 2 

1344.67 1345.10 1 

1345.10 1345.29 Nontypical 

1345.29 1345.45 3 

1345.45 1345.46 Nontypical 

1345.46 1345.50 3 

1345.50 1345.50 Nontypical 

1345.50 1345.57 3 

1345.57 1345.57 Nontypical 

1345.57 1345.60 3 

1345.60 1345.61 Nontypical 

1345.61 1345.76 3 

1345.76 1345.77 Nontypical 

1345.77 1345.93 3 

1345.93 1346.05 Nontypical 
Appendix I2 

Pipeline Construction Right-of-way Cross Sections and Configuration Table 

 I2-4 

Milepost Start Milepost End ROW Typical a

1346.05 1346.16 3 

1346.16 1346.17 Nontypical 

1346.17 1346.26 3 

1346.26 1346.30 Nontypical 

1346.30 1346.51 3 

1346.51 1346.52 Nontypical 

1346.52 1346.53 3 

1346.53 1346.55 Nontypical 

1346.55 1346.56 3 

1346.56 1346.60 Nontypical 

1346.60 1346.63 3 

1346.63 1346.63 Nontypical 

1346.63 1346.69 3 

1346.69 1346.71 2 

1346.71 1346.72 Nontypical 

1346.72 1347.13 2 

1347.13 1347.13 Nontypical 

1347.13 1347.20 2 

1347.20 1347.29 1 

1347.29 1347.30 2 

1347.30 1347.39 1 

1347.39 1347.42 Nontypical 

1347.42 1347.43 2 

1347.43 1347.45 Nontypical 

1347.45 1347.78 1 

1347.78 1348.10 Nontypical 

1348.10 1348.16 1 

1348.16 1348.17 2 

1348.17 1348.18 Nontypical 

1348.18 1348.19 2 

1348.19 1348.20 Nontypical 

1348.20 1348.22 2 

1348.22 1348.24 Nontypical 

1348.24 1348.26 2 

1348.26 1348.27 Nontypical 

1348.27 1348.28 2 

1348.28 1348.46 Nontypical 

1348.46 1348.48 3 

1348.48 1348.49 Nontypical 

1348.49 1348.50 2 

1348.50 1348.53 Nontypical 

1348.53 1348.54 2 

1348.54 1348.55 Nontypical 

1348.55 1348.61 2 

1348.61 1348.62 Nontypical 

1348.62 1348.63 2 

1348.63 1348.94 1 

1348.94 1349.08 Nontypical 

1349.08 1349.32 1 

1349.32 1349.42 Nontypical 

1349.42 1349.46 2 

1349.46 1349.47 Nontypical 

1349.47 1349.55 2 

1349.55 1349.65 Nontypical 

1349.65 1349.66 1 

1349.66 1349.91 Nontypical 

Milepost Start Milepost End ROW Typical a

1349.91 1349.92 1 

1349.92 1349.95 Nontypical 

1349.95 1349.96 1 

1349.96 1349.97 Nontypical 

1349.97 1349.99 2 

1349.99 1349.99 Nontypical 

1349.99 1351.15 1 

1351.15 1351.28 Nontypical 

1351.28 1351.35 2 

1351.35 1351.36 Nontypical 

1351.36 1351.44 2 

1351.44 1351.45 Nontypical 

1351.45 1351.48 2 

1351.48 1351.50 Nontypical 

1351.50 1351.57 2 

1351.57 1351.58 Nontypical 

1351.58 1351.61 2 

1351.61 1351.61 Nontypical 

1351.61 1351.82 2 

Sumner North A Loop

1356.90 1356.91 2 

1356.91 1356.92 1 

1356.92 1356.94 Nontypical 

1356.94 1357.17 1 

1357.17 1357.24 2 

1357.24 1358.00 1 

1358.00 1358.01 2 

1358.01 1358.11 1 

1358.11 1358.16 2 

1358.16 1358.31 1 

1358.31 1358.34 2 

1358.34 1358.47 1 

1358.47 1358.49 2 

1358.49 1358.70 1 

1358.70 1358.73 2 

1358.73 1358.75 1 

1358.75 1358.78 2 

1358.78 1359.00 1 

1359.00 1359.01 2 

1359.01 1359.04 1 

1359.04 1359.14 Nontypical 

1359.14 1359.50 1 

1359.50 1359.56 Nontypical 

1359.56 1359.66 1 

1359.66 1359.83 Nontypical 

1359.83 1360.05 1 

1360.05 1360.07 Nontypical 

1360.07 1360.37 1 

1360.37 1360.39 2 

1360.39 1360.51 1 

1360.51 1360.52 2 

1360.52 1360.63 1 

1360.63 1360.64 2 

1360.64 1360.65 Nontypical 

1360.65 1360.66 2 

1360.66 1360.68 1 
Appendix I2 

Pipeline Construction Right-of-way Cross Sections and Configuration Table 

 I2-5 

Milepost Start Milepost End ROW Typical a

1360.68 1360.69 Nontypical 

1360.69 1360.71 1 

1360.71 1360.75 2 

1360.75 1360.86 1 

1360.86 1360.91 Nontypical 

1360.91 1361.39 1 

1361.39 1361.47 Nontypical 

1361.47 1361.53 1 

1361.53 1361.55 Nontypical 

1361.55 1361.60 1 

1361.60 1361.74 Nontypical 

1361.74 1361.89 2 

1361.89 1361.95 1 

1361.95 1362.27 2 

1362.27 1362.35 1 

1362.35 1362.40 2 

1362.40 1362.42 1 

1362.42 1362.62 2 

1362.62 1362.71 1 

1362.71 1362.83 2 

1362.83 1362.84 3 

1362.84 1362.85 Nontypical 

1362.85 1362.88 3 

1362.88 1363.24 Nontypical 

1363.24 1363.31 2 

1363.31 1363.34 Nontypical 

1363.34 1363.34 2 

1363.34 1363.36 Nontypical 

1363.36 1363.73 2 

1363.73 1363.81 Nontypical 

1363.81 1363.83 2 

1363.83 1363.93 1 

Sumner North B Loop

1370.89 1370.97 1 

1370.97 1371.31 Nontypical 

1371.31 1371.32 2 

1371.32 1371.87 1 

1371.87 1371.89 2 

1371.89 1371.90 Nontypical 

1371.90 1371.91 2 

1371.91 1371.95 1 

1371.95 1371.98 2 

1371.98 1372.02 1 

1372.02 1372.08 Nontypical 

1372.08 1372.09 1 

1372.09 1372.11 2 

1372.11 1372.47 1 

1372.47 1372.61 Nontypical 

1372.61 1372.76 1 

1372.76 1372.78 2 

1372.78 1372.78 Nontypical 

1372.78 1372.82 2 

1372.82 1372.82 Nontypical 

1372.82 1372.97 2 

1372.97 1373.17 Nontypical 

1373.17 1373.25 1 

Milepost Start Milepost End ROW Typical a

1373.25 1373.29 2 

1373.29 1373.52 1 

1373.52 1373.56 Nontypical 

1373.56 1373.65 1 

1373.65 1373.69 2 

1373.69 1373.71 Nontypical 

1373.71 1373.80 2 

1373.80 1373.89 Nontypical 

1373.89 1373.90 2 

1373.90 1373.96 1 

1373.96 1373.96 Nontypical 

1373.96 1373.99 1 

1373.99 1374.06 2 

1374.06 1374.61 1 

1374.61 1374.87 Nontypical 

1374.87 1375.86 1 

1375.86 1375.89 2 

1375.89 1376.69 1 

1376.69 1377.01 2 

1377.01 1377.63 1 

1377.63 1377.65 2 

1377.65 1377.67 1 

1377.67 1377.68 Nontypical 

1377.68 1377.72 2 

1377.72 1377.72 Nontypical 

1377.72 1377.77 2 

1377.77 1377.79 Nontypical 

1377.79 1377.80 2 

1377.80 1377.84 Nontypical 

1377.84 1377.87 2 

1377.87 1377.90 Nontypical 

1377.90 1377.93 2 

1377.93 1377.95 Nontypical 

1377.95 1378.40 2 

1378.40 1378.44 1 

1378.44 1378.45 2 

1378.45 1378.51 1 

1378.51 1378.53 2 

1378.53 1378.57 1 

1378.57 1378.65 2 

1378.65 1378.66 Nontypical 

1378.66 1378.67 2 

1378.67 1378.69 Nontypical 

1378.69 1379.03 2 

1379.03 1379.06 1 

1379.06 1379.14 Nontypical 

1379.14 1379.21 1 

1379.21 1379.23 2 

1379.23 1379.25 Nontypical 

1379.25 1379.32 2 

1379.32 1379.36 Nontypical 

1379.36 1379.83 2 

1379.83 1379.91 1 

1379.91 1380.19 2 

1380.19 1380.21 1 

1380.21 1380.47 2 
Appendix I2 

Pipeline Construction Right-of-way Cross Sections and Configuration Table 

 I2-6 

Milepost Start Milepost End ROW Typical a

1380.47 1380.49 1 

1380.49 1380.68 2 

1380.68 1380.73 1 

1380.73 1380.74 2 

1380.74 1380.87 Nontypical 

1380.87 1381.18 2 

1381.18 1381.27 1 

1381.27 1381.49 Nontypical 

1381.49 1381.75 2 

1381.75 1381.92 Nontypical 

Snohomish Loop

1393.84 1394.06 1 

1394.06 1394.39 Nontypical 

1394.39 1394.41 1 

1394.41 1394.43 2 

1394.43 1394.47 1 

1394.47 1394.48 2 

1394.48 1394.87 1 

1394.87 1394.89 2 

1394.89 1395.30 1 

1395.30 1395.33 2 

1395.33 1395.37 1 

1395.37 1395.49 2 

1395.49 1395.60 1 

1395.60 1396.11 Nontypical 

1396.11 1396.22 1 

1396.22 1396.35 2 

1396.35 1396.59 1 

1396.59 1396.95 Nontypical 

1396.95 1396.99 1 

1396.99 1397.06 Nontypical 

1397.06 1397.39 1 

1397.39 1397.43 2 

1397.43 1398.35 Nontypical 

1398.35 1399.65 1 

1399.65 1399.67 Nontypical 

1399.67 1399.72 1 

1399.72 1399.75 2 

1399.75 1399.89 1 

1399.89 1399.95 2 

1399.95 1399.97 Nontypical 

1399.97 1400.03 2 

1400.03 1400.04 Nontypical 

1400.04 1400.10 2 

1400.10 1400.11 Nontypical 

1400.11 1400.30 2 

1400.30 1400.33 1 

1400.33 1400.34 2 

1400.34 1400.42 1 

1400.42 1400.44 2 

1400.44 1400.45 1 

1400.45 1400.46 2 

1400.46 1400.72 1 

1400.72 1400.87 2 

1400.87 1401.57 4 

1401.57 1401.58 Nontypical 

Milepost Start Milepost End ROW Typical a

1401.58 1402.86 4 

1402.86 1403.21 1 

1403.21 1403.30 2 

1403.30 1403.38 1 

1403.38 1403.40 2 

1403.40 1403.66 1 

1403.66 1403.73 Nontypical 

1403.73 1403.80 1 

1403.80 1403.82 Nontypical 

1403.82 1403.88 1 

1403.88 1403.89 Nontypical 

1403.89 1404.12 1 

1404.12 1404.15 2 

1404.15 1404.32 1 

1404.32 1404.34 2 

1404.34 1404.40 1 

1404.40 1404.43 2 

1404.43 1404.94 1 

1404.94 1404.94 Nontypical 

1404.94 1404.97 1 

1404.97 1405.01 2 

1405.01 1405.36 1 

1405.36 1405.39 2 

1405.39 1405.48 1 

1405.48 1405.49 Nontypical 

1405.49 1405.65 1 

1405.65 1405.70 2 

1405.70 1405.85 1 

1405.85 1405.89 2 

1405.89 1406.00 1 

1406.00 1406.06 Nontypical 

1406.06 1406.08 2 

1406.08 1406.32 1 

1406.32 1406.39 2 

1406.39 1406.53 1 

1406.53 1406.59 2 

1406.59 1406.66 1 

1406.66 1406.67 2 

1406.67 1406.95 1 

1406.95 1407.45 Nontypical 

1407.45 1407.53 2 

1407.53 1407.63 1 

1407.63 1407.64 Nontypical 

1407.64 1407.64 2 

1407.64 1407.93 1 

1407.93 1407.98 2 

1407.98 1407.99 Nontypical 

1407.99 1408.02 2 

1408.02 1408.21 1 

1408.21 1408.22 2 

1408.22 1408.54 1 

1408.54 1408.60 2 

1408.60 1408.75 1 

1408.75 1408.76 Nontypical 

1408.76 1408.95 1 

1408.95 1408.96 2 
Appendix I2 

Pipeline Construction Right-of-way Cross Sections and Configuration Table 

 I2-7 

Milepost Start Milepost End ROW Typical a

1408.96 1409.4 1 

Mt. Vernon South Loop

1435.67 1437.19 1 

1437.19 1437.20 2 

1437.20 1437.60 1 

1437.60 1437.61 2 

1437.61 1437.73 1 

1437.73 1437.74 2 

1437.74 1437.87 1 

1437.87 1437.93 2 

1437.93 1437.96 1 

1437.96 1438.02 2 

1438.02 1438.73 1 

1438.73 1438.76 2 

1438.76 1438.87 1 

1438.87 1438.94 2 

1438.94 1439.00 1 

1439.00 1439.17 Nontypical 

1439.17 1440.07 1 

1440.07 1440.18 Nontypical 

Mt. Vernon North A Loop

1440.20 1441.44 1 

1441.44 1441.45 2 

1441.45 1442.10 1 

1442.10 1442.12 2 

1442.12 1443.08 1 

1443.08 1443.10 2 

1443.10 1444.88 1 

1444.88 1444.97 River Crossing 

1444.97 1444.98 1 

1444.98 1445.02 Nontypical 

Mt. Vernon North B Loop

1453.53 1454.17 1 

1454.17 1454.18 2 

1454.18 1454.24 1 

1454.24 1454.24 2 

1454.24 1454.87 1 

1454.87 1454.88 2 

1454.88 1458.43 1 

1458.43 1458.45 2 

1458.45 1458.47 Nontypical 

1458.47 1458.73 4 

1458.73 1458.78 Nontypical 

1458.78 1458.82 4 

1458.82 1458.95 Nontypical 

1458.95 1459.03 4 

1459.03 1459.39 Nontypical 

1459.39 1459.64 4 

1459.64 1459.66 Nontypical 

1459.66 1460.37 4 

1460.37 1460.48 Nontypical 

1460.48 1461.37 4 

1461.37 1461.74 Nontypical 

1461.74 1461.88 2 

Sumas Loop

1478.58 1478.97 1 

Milepost Start Milepost End ROW Typical a

1478.97 1478.98 Nontypical 

1478.98 1479.29 1 

1479.29 1479.33 2 

1479.33 1479.74 1 

1479.74 1479.76 2 

1479.76 1479.90 1 

1479.90 1479.94 2 

1479.94 1479.98 1 

1479.98 1479.99 2 

1479.99 1480.03 1 

1480.03 1480.05 2 

1480.05 1480.30 1 

1480.30 1480.33 2 

1480.33 1480.68 1 

1480.68 1480.72 2 

1480.72 1480.87 1 

1480.87 1480.88 2 

1480.88 1481.53 1 

1481.53 1481.56 Nontypical 

1481.56 1483.05 4 

1483.05 1483.13 Nontypical 

1483.13 1484.21 4 

1484.21 1484.48 Nontypical 

a The numbers in this column correlate with the 

typical drawings that follow. Nontypical right-of-way 

configurations are those areas for which the typicals 

do not apply. Nontypical configurations occur for 

23.0 miles of WEP. 
Appendix I2 

Pipeline Construction Right-of-way Cross Sections and Configuration Table 

 I2-8 
Appendix I2 

Pipeline Construction Right-of-way Cross Sections and Configuration Table 

 I2-9 
Appendix I2 

Pipeline Construction Right-of-way Cross Sections and Configuration Table 

 I2-10 
Appendix I2 

Pipeline Construction Right-of-way Cross Sections and Configuration Table 

 I2-11 
Appendix I2 

Pipeline Construction Right-of-way Cross Sections and Configuration Table 

 I2-12 
APPENDIX I3 

PIPELINE ROUTE MINOR VARIATIONS

D

D

D

D

1252

1253

1254

1255

 ́

0 1,000 2,000

Feet

LEGEND

Area of Interest

$SSHQGL[,

)LJXUH1

D Washington Expansion Project Route Milepost (10th mile) C

S") Compressor Station

Washington ExpansionProject Route

Minor Route Variations

Kalama River - Option B

*

Kalama River Option C is collocated within the

WEP route, but utilizes a different crossing method.

Kalama River Crossing
0 1,000 2,000

Feet

LEGEND

Area of Interest

Existing Williams Pipeline Route Alternative A Alternative BAlternative B/C

Alternative CAlternative DAlternative E

$SSHQGL[,

)LJXUH

2

2007 Toutle River 

HDD Evaluation
D

D

D

D

D

1275

1276

1277

1273

1274

 ́

0 1,000 2,000

Feet

LEGEND

Area of Interest

$SSHQGL[,

)LJXUH

D Washington Expansion Project Route Milepost (10th mile) C

S") Compressor Station

Washington ExpansionProject Route

Minor Route Variations

Toutle River - Option B

Toutle River - Option CToutle River - Option DToutle River - Option E

Toutle River Crossing
D

D

D

D

D

1309

1310

1311

1312

1313

 ́

0 1,000 2,000

Feet

LEGEND

Area of Interest

$SSHQGL[,

)LJXUH

4

a

D Washington Expansion Project Route Milepost (10th mile) C

S") Compressor Station

Washington ExpansionProject Route

Minor Route Variations

Deschutes River/Vail Moutain -Option B

Deschutes River and Vail Mountain Crossing
D

D

D

1313

1314

1315

 ́

0 1,000 2,000

Feet

LEGEND

Area of Interest

Appendix,

Figure 4b

D Washington Expansion Project Route Milepost (10th mile) C

S") Compressor Station

Washington ExpansionProject Route

Minor Route Variations

Deschutes River/Vail Moutain -Option B

Deschutes River and Vail Mountain Crossing
D

D

D

1379

1380

1381

 ́

0 1,000 2,000

Feet

LEGEND

Area of Interest

Appendix,

Figure 5

D Washington Expansion Project Route Milepost (10th mile) C

S") Compressor Station

Washington ExpansionProject Route

Minor Route Variations

Queens Bog - Option BUnnamed Bog at MP 1381.3 -Option B

Queens Bog and Unnamed Bog at MP 1381.3 Crossing
D

D

D

1443

1444

1445

 ́

0 1,000 2,000

Feet

LEGEND

Area of Interest

Appendix,

Figure 6

D Washington Expansion Project Route Milepost (10th mile)

C

S") Compressor Station

Washington ExpansionProject Route

Minor Route Variations

Skagit River - Option B

Skagit River and Heartbreak Hill Crossing

APPENDIX I4 

ADDITIONAL TEMPORARY WORKSPACE FOR THE PIPELINE ROUTE

Loop 

Number Loop Name ATWS ID Description/Justificationa Access Land Use Cod

1 Woodland 1244.31a Mobilization, pipe stockpile, hydrotest, aboveground facilities installation AR 100.1 62-Nonforested we

21-Cropland and p62-Nonforested we62-Nonforested we11-Residential 14-Transportation, 

1 Woodland 1244.89 Steep terrain ROW 11-Residential 

1 Woodland 1245.12 Removal of existing pipe, equipment staging AR 101 43-Mixed forest lan

1 Woodland 1246.03 Spoil storage, passing lane ROW 21-Cropland and p

1 Woodland 1246.04 Spoil storage, passing lane ROW 21-Cropland and p

1 Woodland 1246.19 Removal of existing pipe, equipment staging AR 103 11-Residential 

1 Woodland 1246.99 Removal of existing pipe, timber storage, equipment staging, nearby 

valve installation

AR 105 43-Mixed forest lan

1 Woodland 1248.09 Steep terrain, point of intersection ROW 43-Mixed forest lan

1 Woodland 1248.21 Steep terrain, point of intersection ROW 21-Cropland and p

21-Cropland and p14-Transportation, 

1 Woodland 1248.65 Spoil storage, slight side hill ROW 21-Cropland and p

1 Woodland 1249.07 Removal of existing pipe, timber storage, equipment staging AR 109.1 43-Mixed forest lan

1 Woodland 1249.21 Removal of existing pipe, timber storage, equipment staging AR 109 43-Mixed forest lan

1 Woodland 1249.22 Side slope AR 109 43-Mixed forest lan

1 Woodland 1249.38 Point of intersection ROW 43-Mixed forest lan

1 Woodland 1250.66 Removal of existing pipe, timber storage, equipment staging AR 110 14-Transportation, 

11-Residential 14-Transportation, 

1 Woodland 1251.67 Removal of existing pipe, timber storage, equipment staging AR 111 43-Mixed forest lan

1 Woodland 1252.46 Steep terrain, timber storage AR 112.1 43-Mixed forest lan

1 Woodland 1252.58 Steep terrain, timber storage ROW 21-Cropland and p

1 Woodland 1252.94 Removal of existing pipe, equipment staging AR 113 43-Mixed forest lan

1 Woodland 1253.37 Point of intersection, river crossing construction, equipment egress, 

hydrotest

AR 114 43-Mixed forest lan

11-Residential 51-Streams and ca

14-Transportation, 11-Residential 14-Transportation, 

1 Woodland 1253.471 Woodland 1253.52 Road crossing, equipment staging Kalama River 

RoadKalama River Road

Point of intersection, river crossing construction, road crossing, hydrotest

Appendix I4

Additional Temporary Workspace for the Pipeline Route

Removal of existing pipe, equipment staging, road crossing, vehicle AR 107parking

1 Woodland 1248.42

China Garden Road

1 Woodland 1251.27 Existing Northwest Pipeline facility, road crossing1 Woodland 1244.31b Mobilization, pipe stockpile, hydrotest AR 100.1

1 Woodland 1244.78 Steep terrain ROW

I4-1
Loop 

Number Loop Name ATWS ID Description/Justificationa Access Land Use Cod

Appendix I4

Additional Temporary Workspace for the Pipeline Route

1 Woodland 1253.95 Equipment/crew staging, parking area AR 115.1 43-Mixed forest lan

1 Woodland 1253.96 Pipe staging, removal of existing pipe, timber storage, steep terrain, 

turnaround area

AR 115.1 43-Mixed forest lan

1 Woodland 1253.97a Equipment/crew staging, parking area AR 115.1 43-Mixed forest lan

1 Woodland 1253.97b Equipment/crew staging, parking area AR 115.1 43-Mixed forest lan

1 Woodland 1253.98 Removal of existing pipe, equipment staging AR 115.1 43-Mixed forest lan

42-Evergreen fores43-Mixed forest lan21-Cropland and p14-Transportation, 

1 Woodland 1256.58 Removal of existing pipe, timber storage, equipment staging AR 117 43-Mixed forest lan

1 Woodland 1256.95 Pipe staging, removal of existing pipe, road crossing, wetland staging Fishpond 

Road

21-Cropland and p

1 Woodland 1257.07 Point of intersection, wetland/stream crossing ROW 21-Cropland and p

1 Woodland 1257.09 Wetland/stream crossing ROW 21-Cropland and p

21-Cropland and p11-Residential 14-Transportation, 

1 Woodland 1257.20 Pipe staging, removal of existing pipe, equipment staging AR 118 21-Cropland and p

21-Cropland and p14-Transportation, 

1 Woodland 1258.19a Existing Northwest Pipeline facility, parking AR 120 14-Transportation, 

1 Woodland 1258.19b Removal of existing pipe, equipment staging, wetland staging AR 120 21-Cropland and p

1 Woodland 1258.33 Passing lane, wetland crossing ROW 21-Cropland and p

43-Mixed forest lan14-Transportation, 43-Mixed forest lan14-Transportation, 43-Mixed forest lan11-Residential 14-Transportation, 43-Mixed forest lan11-Residential 

1 Woodland 1259.16 Steep terrain, stream crossing ROW 43-Mixed forest lan

1 Woodland 1259.36 Steep terrain, stream crossing ROW 43-Mixed forest lan

1 Woodland 1259.55 Steep terrain, stream crossing ROW 43-Mixed forest lan

1 Woodland 1259.02 Side slope, stream crossing ROW

1 Woodland 1258.86 Side slope, wetland crossing AR 120

Points of intersection, road crossing, side slope, 26-inch abandonment AR 120cap

1 Woodland 1258.95

Rose Valley Road

1 Woodland 1257.51 Point of intersection, road crossing, wetland staging

1 Woodland 1258.78 Road crossing AR 121.1

1 Woodland 1255.74 Road crossing, valve installation Kool Road

1 Woodland 1257.15 Wetland/stream crossing, passing lane AR 1181 Woodland 1254.50 Timber storage, turnaround area, equipment staging AR 116

I4-2
Loop 

Number Loop Name ATWS ID Description/Justificationa Access Land Use Cod

Appendix I4

Additional Temporary Workspace for the Pipeline Route

1 Woodland 1259.78 Side slope, steep terrain, stream crossing ROW 43-Mixed forest lan

1 Woodland 1260.07 Steep terrain, stream crossing AR 122 43-Mixed forest lan

21-Cropland and p43-Mixed forest lan62-Nonforested we62-Nonforested we51-Streams and ca

21-Cropland and p51-Streams and ca

62-Nonforested we

1 Woodland 1260.68 Removal of existing pipe, pipe/equipment staging AR 122 21-Cropland and p

1 Woodland 1261.40 Removal of existing pipe, pipe/equipment staging AR 123 43-Mixed forest lan

1 Woodland 1262.23 Removal of existing pipe, timber storage, 26-inch abandonment cap ROW 43-Mixed forest lan1 Woodland 1262.56 Turnaround area, valve installation ROW 11-Residential 

11-Residential 14-Transportation, 

1 Woodland 1263.67 Timber storage, removal of existing pipe, equipment/pipe staging AR 124 43-Mixed forest lan

1 Woodland 1264.16 Point of intersection ROW 43-Mixed forest lan

1 Woodland 1264.90 Waterbody crossing ROW 43-Mixed forest lan

1 Woodland 1264.94 Waterbody crossing ROW 43-Mixed forest lan

1 Woodland 1265.08 Pipe staging, removal of existing pipe, timber storage, road crossing, 

wetland staging

Ostrander Road

21-Cropland and p62-Nonforested we14-Transportation, 21-Cropland and p14-Transportation, 43-Mixed forest lan14-Transportation, 

1 Woodland 1265.22 Wetland staging, stream crossing ROW 43-Mixed forest lan

43-Mixed forest lan14-Transportation, 

1 Woodland 1266.55 Side slope, wetland/stream crossing ROW 43-Mixed forest lan

21-Cropland and p43-Mixed forest lan21-Cropland and p43-Mixed forest lan

1 Woodland 1266.95 Side slope, wetland/stream crossing ROW 43-Mixed forest lan

1 Woodland 1267.00 Side slope, wetland/stream crossing ROW 43-Mixed forest lan

1 Woodland 1266.68 Side slope, wetland/stream crossing ROW

1 Woodland 1266.84 Side slope, wetland/stream crossing ROW

1 Woodland 1265.21 Side slope ROW

1 Woodland 1266.26 Side slope, parking, stream crossing, parking AR 128

1 Woodland 1265.14 Existing Northwest Pipeline facility, parking, road crossing AR 126.1

Pipe staging, removal of existing pipe, timber storage, road crossing, AR 126wetland staging

1 Woodland 1265.17

1260.49 Waterbody crossing, points of intersection, hydrotest AR 122.1/AR 

122.2

1 Woodland

Mt Brynion Road

Existing Northwest Pipeline facility, parking, road crossing, 26-inch abandonment cap

1 Woodland 1262.60

AR 122.1/AR 122.2

Side slope, steep terrain, wetland/waterbody crossing, points of intersection

1 Woodland 1260.44

I4-3
Loop 

Number Loop Name ATWS ID Description/Justificationa Access Land Use Cod

Appendix I4

Additional Temporary Workspace for the Pipeline Route

1 Woodland 1267.11 Wetland/stream crossing, timber storage ROW 43-Mixed forest lan

21-Cropland and p43-Mixed forest lan

1 Woodland 1267.28 Side slope, wetland/stream crossing ROW 43-Mixed forest lan

1 Woodland 1267.31 Wetland/stream crossing, turnaround area, equipment staging ROW 43-Mixed forest lan

21-Cropland and p43-Mixed forest lan14-Transportation, 21-Cropland and p14-Transportation, 43-Mixed forest lan14-Transportation, 

1 Woodland 1267.77 Side slope, stream crossing AR 129 43-Mixed forest lan

1 Woodland 1267.95 Side slope, wetland/stream crossing ROW 43-Mixed forest lan

1 Woodland 1268.20 Side slope, wetland/stream crossing ROW 43-Mixed forest lan

43-Mixed forest lan14-Transportation, 

1 Woodland 1268.60 Side slope, wetland/stream crossing ROW 11-Residential 

1 Woodland 1268.64 Pipe/equipment staging, removal of existing pipe, timber storage AR 130 21-Cropland and p

1 Woodland 1268.75 Wetland/stream crossings, side slope AR 130/ROW 11-Residential 

43-Mixed forest lan11-Residential 

1 Woodland 1269.26 Point of intersection, wetland/stream crossings AR 131 43-Mixed forest lan

1 Woodland 1269.39 Pipe staging, removal of existing pipe, timber storage, road crossing, 

wetland staging

AR 132 21-Cropland and p

43-Mixed forest lan14-Transportation, 

1 Woodland 1269.63 Side slope, point of intersection, 26-inch abandonment cap, road 

crossing, valve installation

Kalmbach Road

43-Mixed forest lan

1 Woodland 1269.75 Side slope, road crossing, stream crossing Kalmbach 

Road

43-Mixed forest lan

1 Woodland 1270.77 Vehicle parking AR 134.1 43-Mixed forest lan

1 Woodland 1271.26 Pipe/equipment staging, timber storage, removal of existing pipe AR 134.2 43-Mixed forest lan

1 Woodland 1272.08 Side slope, point of intersection, 26-inch abandonment cap ROW 43-Mixed forest lan

1 Woodland 1272.19 Pipe/equipment staging, timber storage, removal of existing pipe AR 134 43-Mixed forest lan

1 Woodland 1272.40 Wetland crossing ROW 43-Mixed forest lan

1 Woodland 1272.48 Wetland/stream crossings ROW 43-Mixed forest lan

1 Woodland 1272.51 Point of intersection, timber storage ROW 43-Mixed forest lan

1 Woodland 1269.46 Side slope, point of intersection, 26-inch abandonment cap AR 133

1 Woodland 1268.47 Side slope, wetland/stream crossing AR 130

1 Woodland 1269.04 Point of intersection, wetland/stream crossings ROW

Headquarters Road

1 Woodland 1267.54 Road crossing, pipe/equipment staging

Headquarters Road

1 Woodland 1267.60 Stream crossing, road crossing

1 Woodland 1267.15 Side slope, wetland/stream crossing ROW

Headquarters Road

1 Woodland 1267.49 Wetland/stream crossing, road crossing

I4-4
Loop 

Number Loop Name ATWS ID Description/Justificationa Access Land Use Cod

Appendix I4

Additional Temporary Workspace for the Pipeline Route

1 Woodland 1272.60 Timber storage, removal of existing pipe AR 135 43-Mixed forest lan

1 Woodland 1272.71 Road crossing 504 Road 21-Cropland and p

21-Cropland and p43-Mixed forest lan

1 Woodland 1272.77 Pipe/equipment staging, removal of existing pipe, road crossing 504 Road 21-Cropland and p

21-Cropland and p43-Mixed forest lan43-Mixed forest lan14-Transportation, 

1 Woodland 1273.50 Pipe/equipment staging, removal of existing pipe AR 136.1 43-Mixed forest lan

21-Cropland and p51-Streams and ca

21-Cropland and p

43-Mixed forest lan

51-Streams and ca73-Barren land - N21-Cropland and p43-Mixed forest lan51-Streams and ca

73-Barren land - N43-Mixed forest lan73-Barren land - N

1 Woodland 1276.17 Pipe/equipment staging, removal of existing pipe, timber storage AR 137 43-Mixed forest lan

1 Woodland 1276.95 Parking AR 137.4 42-Evergreen fores

21-Cropland and p42-Evergreen fores43-Mixed forest lan

1 Woodland 1277.33 Side slope, steep terrain, points of intersection, wetland/stream 

crossings

ROW 43-Mixed forest lan

1 Woodland 1277.65 Side slope, points of intersection ROW 42-Evergreen fores

1 Woodland 1278.42 Pipe/equipment staging, removal of existing pipe, timber storage, 

wetland crossing

AR 138 43-Mixed forest lan

1 Woodland 1278.47 Pipe/equipment staging, removal of existing pipe AR 138 43-Mixed forest lan

1 Woodland 1279.04a Pipe/equipment staging, removal of existing pipe, timber storage AR 139 43-Mixed forest lan

1 Woodland 1279.04b Pipe/equipment staging, removal of existing pipe, timber storage AR 139 43-Mixed forest lan

62-Nonforested we62-Nonforested we

1 Woodland 1280.73a Pipe/equipment staging, removal of existing pipe, road crossing Jackson Hwy 21-Cropland and p

Smokey Valley Road

1 Woodland 1279.83 Road crossing, valve installation

1275.43 Passing lane, pipe staging, pipeline crossover, timber storage ROW

1 Woodland1 Woodland

Side slope, steep terrain, points of intersection, wetland/stream AR 137/ROWcrossings

1277.08

1 Woodland 1273.22 Point of intersection ROW

1 Woodland 1273.48 Pipe/equipment staging, removal of existing pipe AR 136.1

1 Woodland 1274.13 Passing lane, equipment staging AR 136.2

1274.22b Spoil placement for waterbody crossing, pipe section layout, sharp point 

of intersection, 26 inch abandonment cap, timber storage, hydrotest

AR 136.3/AR 137.1

1 Woodland 1274.22a Spoil placement for waterbody crossing, timber storage, hydrotest AR 136.31 Woodland

1 Woodland 1272.76 Pipe/equipment staging, removal of existing pipe, road crossing 504 Road

I4-5
Loop 

Number Loop Name ATWS ID Description/Justificationa Access Land Use Cod

Appendix I4

Additional Temporary Workspace for the Pipeline Route

21-Cropland and p14-Transportation, 

1 Woodland 1281.30 Parking, turnaround area AR 141.2 21-Cropland and p

1 Woodland 1281.32 Parking, turnaround area AR 141.2 21-Cropland and p

1 Woodland 1281.78 HDD entry, hydrotest AR 141.1 21-Cropland and p

61-Forested wetlan

43-Mixed forest lan62-Nonforested we

1 Woodland 1282.94 Wetland crossing, pipeline crossover ROW 43-Mixed forest lan

1 Woodland 1283.12 Road crossing Toledo Vader 

Road

42-Evergreen fores

1 Woodland 1283.16 Road crossing, pipe/equipment staging Toledo Vader 

Road

42-Evergreen fores21-Cropland and p14-Transportation, 

1 Woodland 1283.63 Road crossing, pipe/equipment staging Drews Prairie 

Road

21-Cropland and p

1 Woodland 1284.21 Wetland crossing ROW 42-Evergreen fores

1 Woodland 1284.75 Road crossing 505 Hwy 43-Mixed forest lan

43-Mixed forest lan62-Nonforested we21-Cropland and p43-Mixed forest lan

1 Woodland 1285.78 Wetland crossing, parking AR 144 41-Deciduous fores

21-Cropland and p11-Residential 

1 Woodland 1286.57 Pipe/equipment staging, removal of existing pipe AR 145 21-Cropland and p

1 Woodland 1287.16 Pipe/equipment staging, removal of existing pipe AR 146 21-Cropland and p

1 Woodland 1287.53a Road crossing Bremgartner 

Road

21-Cropland and p

1 Woodland 1287.53b Road crossing Bremgartner 

Road

21-Cropland and p21-Cropland and p62-Nonforested we14-Transportation, 

1 Woodland 1288.61 Spoil storage, passing lane, pipe/equipment staging ROW 21-Cropland and p

21-Cropland and p62-Nonforested we14-Transportation, 

Existing Northwest Pipeline facility, demobilization, removal of existing AR 148pipe, aboveground facilities installation, hydrotest

1 Woodland 1289.00

1 Woodland 1286.40 Road crossing Frost Road

1 Woodland 1287.92 Road crossing, wetland crossing Park Road

1 Woodland 1284.78 Road crossing 505 Hwy

Pipe/equipment staging, removal of existing pipe, timber storage, AR 143wetland/stream crossings

1 Woodland 1284.89

1 Woodland 1282.34 HDD pullback AR 142

Drews Prairie Road

1 Woodland 1283.59 Road crossing, wetland crossing

1 Woodland 1280.73b Pipe/equipment staging, removal of existing pipe, road crossing AR 140

I4-6
Loop 

Number Loop Name ATWS ID Description/Justificationa Access Land Use Cod

Appendix I4

Additional Temporary Workspace for the Pipeline Route

2 Chehalis 1291.27 Mobilization, pipe stockpile, hydrotest, aboveground facilities installation Koontz Road 21-Cropland and p

43-Mixed forest lan14-Transportation, 

2 Chehalis 1291.46 Pipe/equipment staging, removal of existing pipe, wetland crossing AR 200 21-Cropland and p

62-Nonforested we62-Nonforested we11-Residential 

2 Chehalis 1292.64 Road crossing Hwy 508 61-Forested wetlan

2 Chehalis 1292.68 Road crossing Hwy 508 11-Residential 

2 Chehalis 1292.69 Road crossing Hwy 508 11-Residential 

2 Chehalis 1292.76 Removal of existing pipe, timber storage, wetland staging AR 202 11-Residential 

21-Cropland and p62-Nonforested we

2 Chehalis 1293.47 Point of intersection, wetland crossing ROW 42-Evergreen fores

2 Chehalis 1293.59 Parking, turnaround area AR 203 42-Evergreen fores

2 Chehalis 1293.60 Parking, turnaround area AR 203 42-Evergreen fores

2 Chehalis 1294.01 HDD entry AR 204 43-Mixed forest lan

21-Cropland and p43-Mixed forest lan14-Transportation, 21-Cropland and p61-Forested wetlan

21-Cropland and p

62-Nonforested we

2 Chehalis 1294.48 Road crossing, wetlands Jackson Hwy 62-Nonforested we

2 Chehalis 1294.54 Road crossing, point of intersection Jackson Hwy 62-Nonforested we

62-Nonforested we62-Nonforested we14-Transportation, 21-Cropland and p43-Mixed forest lan62-Nonforested we21-Cropland and p11-Residential 

2 Chehalis 1295.67 Road crossing Yates Road 21-Cropland and p

2 Chehalis 1296.09 Point of intersection, road crossing, wetland/stream crossings ROW 43-Mixed forest lan

2 Chehalis 1296.12 Road crossing, wetland/stream crossings ROW 43-Mixed forest lan

21-Cropland and p43-Mixed forest lan

Logan Hill Road

2 Chehalis 1296.17 Road crossing, wetland/stream crossings

2 Chehalis 1295.44 Point of intersection, 26-inch abandonment cap ROW

Pipe/equipment staging, removal of existing pipe, road crossing, valve Yates Roadinstallation

2 Chehalis 1295.61

HDD pullback, equipment staging, pipe stockpile, road crossing, Jackson Hwywetlands, vehicle parking 

2 Chehalis 1294.42

2 Chehalis 1294.61 Pipe/equipment staging, removal of existing pipe, wetland crossing AR 205

2 Chehalis 1294.03 HDD entry AR 204

2 Chehalis 1294.14 Access to hydrotest/HDD water AR 204

2 Chehalis 1291.72 Wetland crossing AR 201

Forest Napavine 

2 Chehalis 1293.11 Road crossing, wetland staging

2 Chehalis 1291.35 Road crossing, wetland/stream crossing Koontz Road

I4-7
Loop 

Number Loop Name ATWS ID Description/Justificationa Access Land Use Cod

Appendix I4

Additional Temporary Workspace for the Pipeline Route

21-Cropland and p43-Mixed forest lan

2 Chehalis 1296.31 Removal of existing pipe, pipe/equipment staging AR 208 21-Cropland and p

2 Chehalis 1297.83 Removal of existing pipe, pipe/equipment staging, timber storage AR 210 42-Evergreen fores

2 Chehalis 1298.17 Existing Northwest Pipeline facility, road crossing, parking Centralia 

Alpha Road

14-Transportation, 42-Evergreen fores43-Mixed forest lan14-Transportation, 

2 Chehalis 1298.96 Timber storage, wetland/stream crossing, pipe/equipment staging ROW 21-Cropland and p

43-Mixed forest lan14-Transportation, 

2 Chehalis 1299.64 Removal of existing pipe, pipe/equipment staging, timber storage AR 211.1 43-Mixed forest lan

43-Mixed forest lan62-Nonforested we

2 Chehalis 1300.34 Removal of existing pipe, pipe/equipment staging, timber storage AR 212 43-Mixed forest lan

2 Chehalis 1300.51 Point of intersection ROW 43-Mixed forest lan

2 Chehalis 1300.63 Point of intersection ROW 43-Mixed forest lan

2 Chehalis 1300.98 Point of intersection, side slope ROW 14-Transportation, 

2 Chehalis 1301.06 Point of intersection, side slope ROW 14-Transportation, 

2 Chehalis 1301.07 Point of intersection, side slope, equipment staging ROW 43-Mixed forest lan

21-Cropland and p62-Nonforested we21-Cropland and p62-Nonforested we

Points of intersection AR 214 43-Mixed forest lan

14-Transportation, 

2 Chehalis 1302.94 Removal of existing pipe, pipe/equipment staging AR 214.2 43-Mixed forest lan

2 Chehalis 1304.23 Road crossing, stream crossing AR 215 43-Mixed forest lan

2 Chehalis 1304.31 Pipe/equipment staging, removal of existing pipe, timber storage, road 

i tl d i

AR 216 62-Nonforested we

2 Chehalis 1304.31 Pipe/equipment staging, removal of existing pipe, timber storage, road 

crossing wetland crossing

AR 216 75-Strip mines, qua

2 Chehalis 1305.07 wetland/stream crossing AR 216.1 43-Mixed forest lan

43-Mixed forest lan75-Strip mines, qua

2 Chehalis 1305.79 Pipe/equipment staging, removal of existing pipe, timber storage, road 

crossing

AR 216 43-Mixed forest lan

Pipe/equipment staging, removal of existing pipe, timber storage, road AR 216crossing

2 Chehalis 1305.70

Little Hanaford 

2 Chehalis 1301.61 Road crossing, wetland crossing

2 Chehalis 1302.24

2 Chehalis 1300.08 wetland crossing AR 212.2

Little Hanaford 

Pipe/equipment staging, removal of existing pipe, timber storage, road crossing, wetland crossing

2 Chehalis 1301.542 Chehalis

2 Chehalis 1299.08 Road crossing Profitt Road

Centralia Alpha Road

1298.20 Road crossing, equipment staging

ROW via Logan Hill 

2 Chehalis 1296.20 Road crossing, wetland/stream crossings

I4-8
Loop 

Number Loop Name ATWS ID Description/Justificationa Access Land Use Cod

Appendix I4

Additional Temporary Workspace for the Pipeline Route

2 Chehalis 1306.65 Road crossing Big Hanaford 

Road

21-Cropland and p43-Mixed forest lan62-Nonforested we

2 Chehalis 1308.01 Points of intersection AR 218 14-Transportation, 

2 Chehalis 1308.06 Points of intersection AR 218.3 14-Transportation, 

43-Mixed forest lan

62-Nonforested we

2 Chehalis 1309.32 Waterbody crossing, points of intersection ROW 43-Mixed forest lan

21-Cropland and p43-Mixed forest lan21-Cropland and p14-Transportation, 

2 Chehalis 1309.81 Point of intersection, road crossing, 26-inch abandonment cap AR 220 14-Transportation, 

2 Chehalis 1309.99 Equipment and pipe staging/layout area for short section of non-typical 

construction workspace

ROW 21-Cropland and p

21-Cropland and p43-Mixed forest lan14-Transportation, 

2 Chehalis 1310.40 Side slope, steep terrain, passing lane ROW 43-Mixed forest lan2 Chehalis 1310.51 Side slope, steep terrain, passing lane ROW 21-Cropland and p

21-Cropland and p43-Mixed forest lan43-Mixed forest lan14-Transportation, 

2 Chehalis 1312.32 Pipe/equipment staging, removal of existing pipe, timber storage AR 221 43-Mixed forest lan

43-Mixed forest lan62-Nonforested we43-Mixed forest lan14-Transportation, 

2 Chehalis 1314.10 Pipe/equipment staging, removal of existing pipe, timber storage AR 223 43-Mixed forest lan2 Chehalis 1314.28 Pipe/equipment staging, removal of existing pipe, timber storage AR 223 43-Mixed forest lan

43-Mixed forest lan62-Nonforested we

2 Chehalis 1315.13 Waterbody crossing, steep terrain, hydrotest ROW 43-Mixed forest lan2 Chehalis 1315.15 Waterbody crossing, steep terrain, hydrotest ROW 43-Mixed forest lan

2 Chehalis 1314.47 Steep terrain, side slope AR 223

2 Chehalis 1312.73 Pipe/equipment staging, removal of existing pipe, timber storage AR 221.2

2 Chehalis 1313.20 Pipe/equipment staging, removal of existing pipe, timber storage AR 221.3

2 Chehalis 1310.96 Steep terrain, side slope, timber storage ROW

2 Chehalis 1311.80 Point of intersection AR 221

Skookumchuck Road

Removal of existing pipe, pipe/equipment staging, sharp point of intersection, road crossing, valve installation

2 Chehalis 1309.77

Skookumchuck Road

Removal of existing pipe, pipe/equipment staging, sharp point of intersection, cross-over

2 Chehalis 1310.12

2 Chehalis 1309.03 Stream crossing, access AR 218

2 Chehalis 1309.40 Waterbody crossing, points of intersection, hydrotest ROW

2 Chehalis 1307.28 Pipe/equipment staging, removal of existing pipe AR 218.1

I4-9
Loop 

Number Loop Name ATWS ID Description/Justificationa Access Land Use Cod

Appendix I4

Additional Temporary Workspace for the Pipeline Route

2 Chehalis 1315.62 Existing Northwest Pipeline facility, demobilization, removal of existing 

pipe, aboveground facilities removal

AR 225 14-Transportation, 

21-Cropland and p43-Mixed forest lan14-Transportation, 21-Cropland and p43-Mixed forest lan14-Transportation, 

3 Sumner South 1338.14 Road crossing, pipe stockpile 192nd St 21-Cropland and p

15-Industrial and c14-Transportation, 15-Industrial and c14-Transportation, 15-Industrial and c14-Transportation, 

3 Sumner South 1338.63 Removal of existing pipe, pipe/equipment staging, road crossing, parking 184th St 15-Industrial and c3 Sumner South 1338.73 Spoil and concrete storage 184th St 15-Industrial and c

21-Cropland and p

14-Transportation, 42-Evergreen fores43-Mixed forest lan62-Nonforested we14-Transportation, 11-Residential 14-Transportation, 

3 Sumner South 1339.30 Road crossing 176th St 42-Evergreen fores

3 Sumner South 1339.35 Road crossing, wetland 176th St 11-Residential 

21-Cropland and p11-Residential 21-Cropland and p43-Mixed forest lan43-Mixed forest lan11-Residential 

3 Sumner South 1340.69 Road crossing, parking, turnaround area AR 302.2 11-Residential 

3 Sumner South 1340.15 Stream crossing, pipe/equipment staging ROW

3 Sumner South 1340.61 Removal of existing pipe, pipe/equipment staging, parking AR 302.1

3 Sumner South 1339.24 Existing Northwest Pipeline facility, parking, valve removal ROW

3 Sumner South 1339.45 Removal of existing pipe, pipe/equipment staging, road crossing, parking 176th St

Fredrickson Industrial Park

3 Sumner South 1338.87 Road/railroad crossing, pipe/equipment staging, parking

3 Sumner South 1339.18 Points of intersection, 26" abandonment caps ROW

3 Sumner South 1338.37 Road/railroad crossing, parking Canyon Road

3 Sumner South 1338.45 Parking Canyon Road

Existing Northwest Pipeline facility, mobilization, pipe stockpile, road 192nd Stcrossing

3 Sumner South 1338.03

3 Sumner South 1338.33 Removal of existing pipe, road crossing, parking Canyon Road

Existing Northwest Pipeline facility, demobilization, removal of existing AR 225pipe

2 Chehalis 1315.63

I4-10
Loop 

Number Loop Name ATWS ID Description/Justificationa Access Land Use Cod

Appendix I4

Additional Temporary Workspace for the Pipeline Route

21-Cropland and p43-Mixed forest lan

3 Sumner South 1341.13 Spoil storage ROW 11-Residential 

21-Cropland and p11-Residential 

3 Sumner South 1341.24 Parking, Road Crossing 76th Ave 11-Residential 

21-Cropland and p62-Nonforested we11-Residential 12-Commercial and 41-Deciduous fores14-Transportation, 

3 Sumner South 1342.41 wetland crossings ROW 41-Deciduous fores

3 Sumner South 1342.63 Removal of existing pipe, pipe/equipment staging, road crossing, 

parking, stream crossing

AR 305 41-Deciduous fores

12-Commercial and 41-Deciduous fores11-Residential 14-Transportation, 11-Residential 14-Transportation, 12-Commercial and 21-Cropland and p11-Residential 11-Residential 14-Transportation, 

3 Sumner South 1343.32 Road crossing 128th St 11-Residential 

11-Residential 14-Transportation, 

3 Sumner South 1343.51 Pipe/equipment staging access 98th Ave 11-Residential 

3 Sumner South 1343.52 Pipe/equipment staging, nearby valve installation 98th Ave 11-Residential 

3 Sumner South 1343.68 Spoil storage, point of intersection 99th Ave 

E /ROW

11-Residential 11-Residential 14-Transportation, 

3 Sumner South 1343.73 Spoil storage 122nd St

3 Sumner South 1343.28 Road crossing, Existing Northwest Facility 128th St

3 Sumner South 1343.45 Spoil storage 126th St

3 Sumner South 1342.98 Pipe/equipment staging, spoil storage 94th Ave

3 Sumner South 1343.19 Pipe/equipment staging, spoil storage ROW

3 Sumner South 1342.78 Road crossing, pipe/equipment staging 94th Ave

3 Sumner South 1342.84 Sharp point of intersection, road crossing 94th Ave

3 Sumner South 1342.14 Removal of existing pipe, pipe/equipment staging, road crossing, parking 86th Ave

3 Sumner South 1342.17 Pipe/equipment staging, road crossing, parking, wetlands 86th Ave

3 Sumner South 1341.07 Removal of existing pipe, pipe/equipment staging, parking AR 303

3 Sumner South 1341.21 Spoil storage AR 304

I4-11
Loop 

Number Loop Name ATWS ID Description/Justificationa Access Land Use Cod

Appendix I4

Additional Temporary Workspace for the Pipeline Route

12-Commercial and 14-Transportation, 

3 Sumner South 1343.93 Road crossing Meridian Ave 12-Commercial and 

3 Sumner South 1343.95 Road crossing Meridian Ave 12-Commercial and 

3 Sumner South 1344.11 Pipe staging, points of intersection, parking, spoil storage ROW 12-Commercial and 

12-Commercial and 11-Residential 21-Cropland and p42-Evergreen fores

3 Sumner South 1344.64 Road crossing, spoil storage ROW 11-Residential 

11-Residential 14-Transportation, 43-Mixed forest lan14-Transportation, 11-Residential 14-Transportation, 

3 Sumner South 1345.57 Removal of existing pipe, pipe/equipment staging, road crossing, 

parking, spoil storage

Thornhill Road

11-Residential 

3 Sumner South 1345.68 Removal of existing pipe, pipe/equipment staging, road crossing, 

parking, spoil storage

Larkspur Dr 11-Residential 

3 Sumner South 1345.72 Removal of existing pipe, pipe/equipment staging, road crossing, 

parking, spoil storage

ROW via 20th St

11-Residential 43-Mixed forest lan62-Nonforested we62-Nonforested we21-Cropland and p62-Nonforested we14-Transportation, 21-Cropland and p62-Nonforested we62-Nonforested we14-Transportation, 21-Cropland and p62-Nonforested we14-Transportation, 

Road/railroad crossing, pipe/equipment staging, spoil storage, point of AR 309intersection

3 Sumner South 1347.35

3 Sumner South 1347.25 Existing Northwest Pipeline facility, road/railroad crossing, parking Pioneer Way

Road/railroad crossing, pipe/equipment staging, spoil storage, point of AR 309intersection

3 Sumner South 1347.33

Removal of existing pipe, pipe/equipment staging, road crossing, 31st Aveparking, spoil storage

3 Sumner South 1345.44

Pipe/equipment staging, point of Intersection, wetland staging, valve 12th Aveinstallation

3 Sumner South 1346.91

3 Sumner South 1344.69 Road crossing 39th Ave

3 Sumner South 1344.72 Road crossing 39th Ave

3 Sumner South 1344.20 Pipe staging, side slope ROW

Removal of existing pipe, pipe stockpile, equipment staging, road 43rd Avecrossing, wetland crossing

3 Sumner South 1344.42

120th St/ROW

3 Sumner South 1343.89 Point of intersection

I4-12
Loop 

Number Loop Name ATWS ID Description/Justificationa Access Land Use Cod

Appendix I4

Additional Temporary Workspace for the Pipeline Route

21-Cropland and p62-Nonforested we21-Cropland and p43-Mixed forest lan62-Nonforested we

3 Sumner South 1348.02 HDD exit, spoil storage ROW via AR 

311

11-Residential 21-Cropland and p43-Mixed forest lan62-Nonforested we21-Cropland and p62-Nonforested we21-Cropland and p62-Nonforested we

3 Sumner South 1349.35 Highway crossing ROW 21-Cropland and p

3 Sumner South 1349.35 Highway crossing ROW 14-Transportation, 

12-Commercial and 21-Cropland and p62-Nonforested we11-Residential 14-Transportation, 62-Nonforested we11-Residential 14-Transportation, 

3 Sumner South 1349.67 Road crossing, spoil storage 64th St 11-Residential 

21-Cropland and p11-Residential 14-Transportation, 

3 Sumner South 1350.98 Road crossing, pipe/equipment staging ROW 21-Cropland and p

3 Sumner South 1351.26 Pipe/equipment staging, road crossing, parking, spoil storage 38th St 21-Cropland and p

11-Residential 14-Transportation, 

3 Sumner South 1349.8 Spoil storage, timber storage, pipe/equipment staging 60th St/ROW

Compressor Station (166th Ave)

Existing Northwest Pipeline facility, demobilization, removal of existing pipe, aboveground facilities removal, hydrotest

3 Sumner South 1351.74

3 Sumner South 1349.54 Spoil storage, sharp point of intersection, road crossing 64th St

3 Sumner South 1349.62 Road crossing, parking 64th St

3 Sumner South 1349.07 Point of intersection, pipeline crossover ROW

3 Sumner South 1349.26 Highway crossing AR 314

3 Sumner South 1347.86 Access to hydrotest/HDD water AR 310

Removal of existing pipe, point of intersection, pipeline crossover, spoil ROWstorage

3 Sumner South 1348.88

ROW via AR 309

3 Sumner South 1347.60 HDD pullback and entry point

I4-13
Loop 

Number Loop Name ATWS ID Description/Justificationa Access Land Use Cod

Appendix I4

Additional Temporary Workspace for the Pipeline Route

21-Cropland and p41-Deciduous fores61-Forested wetlan

21-Cropland and p14-Transportation, 

4 Sumner North A 1356.90c Existing Northwest Pipeline facility, mobilization, removal of existing 

pipe, road crossing

Green Valley Road

21-Cropland and p

4 Sumner North A 1356.92 Road crossing, avoidance of structure on east side of ROW Green Valley 

Road

11-Residential 

4 Sumner North A 1357.49 Point of intersection, equipment staging, parking, access AR 401 43-Mixed forest lan

4 Sumner North A 1358.01 Removal of existing pipe, pipe/equipment staging, road crossing, point of 

Intersection, valve installation

Lake Holm Road

11-Residential 

43-Mixed forest lan14-Transportation, 

4 Sumner North A 1358.84 Road crossings, hydrotest 326th St 41-Deciduous fores

4 Sumner North A 1359.09 Turnaround area, parking, spoil storage, pipe/equipment staging ROW via 

322nd St

11-Residential 21-Cropland and p42-Evergreen fores

4 Sumner North A 1359.33b Pipe staging, timber storage, spoil storage ROW 21-Cropland and p

4 Sumner North A 1359.65 Road crossing, spoil storage pipe/equipment staging 169th Ave 11-Residential 

4 Sumner North A 1360.04 Removal of existing pipe, avoidance of structure on east side of ROW AR 405 11-Residential 4 Sumner North A 1360.12 Existing Northwest Pipeline facility, road crossing, parking Kent Black 

Diamond Road

14-Transportation, 43-Mixed forest lan14-Transportation, 43-Mixed forest lan11-Residential 43-Mixed forest lan14-Transportation, 21-Cropland and p62-Nonforested we14-Transportation, 21-Cropland and p11-Residential 14-Transportation, 

4 Sumner North A 1361.58 Road crossing, pipe/equipment staging AR 409

4 Sumner North A 1360.88 Point of intersection, road crossing, wetland crossing Thomas Road

4 Sumner North A 1361.08 wetland crossing AR 408 

4 Sumner North A 1360.47 Removal of existing pipe, pipe/equipment staging AR 406

Removal of existing pipe, pipe/equipment staging, timber storage, spoil AR 407storage

4 Sumner North A 1360.59

Lake Holm Road

4 Sumner North A 1358.10 Road crossing, wetland staging

4 Sumner North A 1359.33a Pipe staging, timber storage, spoil storage ROW

ROW via Green Valley Road

4 Sumner North A 1356.90a Access to hydrotest/HDD water

Green Valley Road

Existing Northwest Pipeline facility, mobilization, removal of existing pipe, road crossing, hydrotest, aboveground facility installation

4 Sumner North A 1356.90b

I4-14
Loop 

Number Loop Name ATWS ID Description/Justificationa Access Land Use Cod

Appendix I4

Additional Temporary Workspace for the Pipeline Route

12-Commercial and 11-Residential 11-Residential 14-Transportation, 

4 Sumner North A 1361.99 Turnaround area, parking ROW 11-Residential 

4 Sumner North A 1362.05 Spoil storage, equipment/pipe staging ROW 11-Residential 

11-Residential 14-Transportation, 

4 Sumner North A 1362.69 Railroad crossing, stream crossing, points of intersection, 26-inch 

abandonment cap

ROW 11-Residential 

4 Sumner North A 1362.79 Existing Northwest Pipeline facility, road crossing, parking, 

equipment/pipe staging, removal of existing pipe

516th St 14-Transportation, 

4 Sumner North A 1363.51 Equipment/pipe staging, spoil storage 262nd St 43-Mixed forest lan

43-Mixed forest lan14-Transportation, 

5 Sumner North B 1370.89 Existing Northwest Pipeline facility, removal of existing pipe and 

aboveground facility, pipe/equipment staging, road crossing

AR 500 41-Deciduous fores

41-Deciduous fores62-Nonforested we

5 Sumner North B 1371.20 Removal of existing pipe, pipe/equipment staging AR 501 41-Deciduous fores

41-Deciduous fores11-Residential 

5 Sumner North B 1371.54 Stream crossings, staging ROW 43-Mixed forest lan5 Sumner North B 1371.89 Road crossing, stream crossing Issaquah 

Hobart Dr

43-Mixed forest lan11-Residential 14-Transportation, 15-Industrial and c11-Residential 

5 Sumner North B 1372.88 Removal of existing pipe, pipe/equipment staging IssaquahHobart Rd 11-Residential 

21-Cropland and p42-Evergreen fores11-Residential 

5 Sumner North B 1372.86 Pipeline crossover, spoil storage AR 507

5 Sumner North B 1373.91 Timber storage ROW

5 Sumner North B 1371.28 Equipment/pipe staging, spoil storage, timber storage AR 502

5 Sumner North B 1372.75 Existing Northwest Pipeline facility, parking AR 505

Existing Northwest Pipeline facility, demobilization, removal of existing AR 413pipe, aboveground facilities removal, hydrotest

4 Sumner North A 1363.92

5 Sumner North B 1371.14 Stream crossing, wetland staging, point of Intersection ROW

4 Sumner North A 1361.92 Spoil storage, pipe/equipment staging ROW

4 Sumner North A 1362.63 Railroad crossing, stream crossing ROW

4 Sumner North A 1361.64 Avoidance of firehouse, valve removal AR 410

I4-15
Loop 

Number Loop Name ATWS ID Description/Justificationa Access Land Use Cod

Appendix I4

Additional Temporary Workspace for the Pipeline Route

41-Deciduous fores43-Mixed forest lan11-Residential 14-Transportation, 

5 Sumner North B 1375.65 Parking, timber storage AR 512 14-Transportation, 

42-Evergreen fores43-Mixed forest lan14-Transportation, 42-Evergreen fores14-Transportation, 

5 Sumner North B 1376.08b Highway crossing I-90 14-Transportation, 

5 Sumner North B 1376.09 Highway crossing, stream crossing I-90 14-Transportation, 

5 Sumner North B 1376.13 Highway crossing, stream crossing I-90 14-Transportation, 

43-Mixed forest lan14-Transportation, 43-Mixed forest lan14-Transportation, 

5 Sumner North B 1376.26 Parking, turnaround area, hydrotest ROW 43-Mixed forest lan

5 Sumner North B 1376.47 Road crossing, spoil storage ROW 14-Transportation, 5 Sumner North B 1377.07 Steep terrain, road crossings Black Nugget 

Road

43-Mixed forest lan

5 Sumner North B 1377.14 Pipe/equipment staging, parking Black Nugget 

Road

43-Mixed forest lan43-Mixed forest lan62-Nonforested we62-Nonforested we

5 Sumner North B 1377.43 wetland crossings ROW 43-Mixed forest lan

12-Commercial and 43-Mixed forest lan

5 Sumner North B 1377.62 Road crossing Issaquah Fall 

City Road

14-Transportation, 

5 Sumner North B 1378.42 Removal of existing pipe, pipe/equipment staging, spoil storage 244th Pl 43-Mixed forest lan5 Sumner North B 1378.55 Road crossing Klahanie Blvd 43-Mixed forest lan

5 Sumner North B 1377.54 Removal of existing pipe, pipe/equipment staging, timber storage ROW

5 Sumner North B 1376.17b Highway crossing, stream crossing I-90

5 Sumner North B 1377.40 wetland crossings AR 514

5 Sumner North B 1376.08a Highway crossing I-90

5 Sumner North B 1376.17a Highway crossing, stream crossing I-90

Removal of existing pipe, pipe/equipment staging, points of intersection, AR 51126-inch abandonment caps

5 Sumner North B 1374.20

Removal of existing pipe, pipe/equipment staging, points of intersection, AR 51226-inch abandonment caps

5 Sumner North B 1375.67

I4-16
Loop 

Number Loop Name ATWS ID Description/Justificationa Access Land Use Cod

Appendix I4

Additional Temporary Workspace for the Pipeline Route

5 Sumner North B 1379.05 Wetland crossing, 26” abandonment ROW 43-Mixed forest lan

43-Mixed forest lan14-Transportation, 

5 Sumner North B 1379.19 Existing Northwest Pipeline facility, parking, abovegound facility 

installation

32nd St 14-Transportation, 

5 Sumner North B 1379.28 Passing lane, parking, turnaround area, spoil storage ROW 11-Residential 

5 Sumner North B 1380.61 Removal of existing pipe, pipe/equipment staging, passing lane, parking, 

turnaround area

ROW 11-Residential 

5 Sumner North B 1380.70 Road crossing, staging 244th Ave 41-Deciduous fores

21-Cropland and p11-Residential 

5 Sumner North B 1381.22 Pipe/equipment staging for wetland crossing, steep terrain ROW 43-Mixed forest lan

43-Mixed forest lan62-Nonforested we11-Residential 51-Streams and ca

61-Forested wetlan

43-Mixed forest lan62-Nonforested we61-Forested wetlan

43-Mixed forest lan

5 Sumner North B 1381.84 Removal of existing pipe, demobilization, timber storage AR 518.1 43-Mixed forest lan

43-Mixed forest lan62-Nonforested we43-Mixed forest lan14-Transportation, 

6 Snohomish 1395.93 Pipe/equipment staging, wetland crossing ROW 21-Cropland and p

43-Mixed forest lan14-Transportation, 21-Cropland and p43-Mixed forest lan14-Transportation, 

6 Snohomish 1397.40 HDD pullback ROW 21-Cropland and p

21-Cropland and p43-Mixed forest lan62-Nonforested we

6 Snohomish 1397.92 HDD entry, point of intersection, 26-inch abandonment cap, hydrotest AR 603 43-Mixed forest lan

6 Snohomish 1397.43 HDD pullback, point of intersection ROW

6 Snohomish 1396.95 Highway crossing, parking Hwy 522

6 Snohomish 1397.05 26-inch abandonment cap, sharp point of intersection Elliott Road

Existing Northwest Pipeline facility, hydrotest, aboveground facility AR 518removal

5 Sumner North B 1381.89

Echo Lake Road

Existing Northwest Pipeline facility, mobilization, pipe/equipment staging, road crossing, aboveground facility installation

6 Snohomish 1393.94

ROW via AR 517

5 Sumner North B 1381.49a Pipe/equipment staging for wetland crossing, steep terrain

ROW via AR 517

5 Sumner North B 1381.49b Pipe/equipment staging for wetland crossing, steep terrain

Removal of existing pipe, pipe/equipment staging, passing lane, parking, ROWturnaround area, spoil storage

5 Sumner North B 1380.90

5 Sumner North B 1381.26 Pipe/equipment staging for wetland crossing, steep terrain ROW

5 Sumner North B 1379.18 Wetland crossing, road crossing 32nd St

I4-17
Loop 

Number Loop Name ATWS ID Description/Justificationa Access Land Use Cod

Appendix I4

Additional Temporary Workspace for the Pipeline Route

43-Mixed forest lan14-Transportation, 21-Cropland and p43-Mixed forest lan51-Streams and ca

14-Transportation, 

6 Snohomish 1398.64 Steep terrain, wetland crossings ROW 43-Mixed forest lan

41-Deciduous fores43-Mixed forest lan

6 Snohomish 1399.49 Steep terrain, wetland crossings ROW 41-Deciduous fores

41-Deciduous fores43-Mixed forest lan

6 Snohomish 1399.82 Steep terrain, wetland crossings 139th Ave SE 14-Transportation, 

6 Snohomish 1400.74 Road crossing, removal of existing pipe, pipe/equipment staging Old 

Snohomish Monroe Road

21-Cropland and p

6 Snohomish 1400.74 Road crossing, removal of existing pipe, pipe/equipment staging Old 

Snohomish Monroe Road

14-Transportation, 21-Cropland and p43-Mixed forest lan14-Transportation, 

6 Snohomish 1401.59 Road crossing AR 605 43-Mixed forest lan

21-Cropland and p62-Nonforested we21-Cropland and p62-Nonforested we

6 Snohomish 1402.41 Ditch crossing ROW 21-Cropland and p

6 Snohomish 1402.44 Ditch crossing ROW 21-Cropland and p

21-Cropland and p61-Forested wetlan

62-Nonforested we14-Transportation, 

6 Snohomish 1402.97 Existing Northwest Pipeline facility, road crossing, removal of existing 

pipe, pipe/equipment staging, point of intersection

State Hwy 2- Stevens Pass Hwy

14-Transportation, 

Road crossing, removal of existing pipe, pipe/equipment staging, point of AR 606intersection

6 Snohomish 1402.88

6 Snohomish 1401.60 Road crossing AR 605

6 Snohomish 1401.62 Road crossing, removal of existing pipe, pipe/equipment staging AR 605

6 Snohomish 1399.82 Steep terrain, wetland crossings 139th Ave SE 

6 Snohomish 1401.58 Road crossing AR 605

6 Snohomish 1398.19 HDD entry, pipe/equipment staging AR 603.1

6 Snohomish 1399.00 Steep terrain, wetland crossings ROW

6 Snohomish 1398.02 Valve installation AR 603.1

I4-18
Loop 

Number Loop Name ATWS ID Description/Justificationa Access Land Use Cod

Appendix I4

Additional Temporary Workspace for the Pipeline Route

6 Snohomish 1403.72 Removal of existing pipe, pipe/equipment staging AR 608 21-Cropland and p

6 Snohomish 1403.90 Road crossing 84th St 21-Cropland and p

43-Mixed forest lan62-Nonforested we62-Nonforested we

6 Snohomish 1404.96 Road crossing Three Lakes 

Road

11-Residential 

6 Snohomish 1405.15 Valve installation, 26-inch abandonment cap, wetland crossing, and spoil 

storage for pipeline crossover

ROW via AR 609

43-Mixed forest lan

6 Snohomish 1406.72 Pipeline crossover, road crossing ROW via 

Dubuque Road

11-Residential 

6 Snohomish 1406.78 Road crossing, parking Dubuque 

Road

14-Transportation, 

6 Snohomish 1407.04 Removal of existing pipe, pipe/equipment staging AR 611 21-Cropland and p

6 Snohomish 1407.78a Point of intersection, steep terrain, waterbody crossing ROW 43-Mixed forest lan

6 Snohomish 1407.78b Point of intersection, steep terrain, waterbody crossing ROW 43-Mixed forest lan

6 Snohomish 1407.84a Point of intersection, steep terrain, waterbody crossing, road crossing, 

hydrotest water access

Pilchuck Way 43-Mixed forest lan

6 Snohomish 1407.84b Point of intersection, steep terrain, waterbody crossing, road crossing, 

hydrotest water access

Pilchuck Way 43-Mixed forest lan

21-Cropland and p43-Mixed forest lan

6 Snohomish 1407.89 Removal of existing pipe, pipe/equipment staging, pipe stockpile Pilchuck Way 21-Cropland and p

21-Cropland and p43-Mixed forest lan14-Transportation, 43-Mixed forest lan14-Transportation, 

6 Snohomish 1409.39 Existing Northwest Pipeline facility, demobilization, removal of existing 

pipe, road crossing, wetland crossing, hydrotest, aboveground facility removal

ROW via Meridian St

14-Transportation, 43-Mixed forest lan14-Transportation, 43-Mixed forest lan14-Transportation, 

Lake Cavanaugh Road

7 Mt Vernon South 1435.70 Road crossing

Existing Northwest Pipeline facility, demobilization, removal of existing Meridian Stpipe, road crossing, wetland crossing, hydrotest, aboveground facility removal

6 Snohomish 1409.35

Lake Cavanaugh Road

Existing Northwest Pipeline facility, mobilization, pipe/equipment staging, road crossing, hydrotest, aboveground facility installation

7 Mt Vernon South 1435.67

6 Snohomish 1407.88 Removal of existing pipe, pipe/equipment staging Pilchuck Way

Existing Northwest Pipeline facility, removal of existing pipe, AR 613pipe/equipment staging

6 Snohomish 1408.50

Road crossing, removal of existing pipe, pipe/equipment staging, 26-inch 80th Stabandonment cap, hydrotest

6 Snohomish 1404.21

I4-19
Loop 

Number Loop Name ATWS ID Description/Justificationa Access Land Use Cod

Appendix I4

Additional Temporary Workspace for the Pipeline Route

43-Mixed forest lan14-Transportation, 

Passing lane, parking 41-Deciduous fores

43-Mixed forest lan41-Deciduous fores14-Transportation, 41-Deciduous fores11-Residential 14-Transportation, 

7 Mt Vernon South 1437.05 Passing lane, hilly terrain, side slope Crestwood Dr 41-Deciduous fores

7 Mt Vernon South 1437.10 Turnaround area, parking, staging Briarwood Ct 41-Deciduous fores

41-Deciduous fores11-Residential 

7 Mt Vernon South 1437.46 Point of intersection ROW 21-Cropland and p

7 Mt Vernon South 1437.69 Point of intersection ROW 21-Cropland and p

7 Mt Vernon South 1437.77a Road crossing, pipe/equipment staging Walker Valley 

Road

14-Transportation, 

7 Mt Vernon South 1437.77b Road crossing, pipe/equipment staging Walker Valley 

Road

14-Transportation, 42-Evergreen fores61-Forested wetlan

7 Mt Vernon South 1439.00 Wetland crossings, points of intersection, 26-inch abandonment cap ROW 21-Cropland and p7 Mt Vernon South 1439.18 Wetland crossings, points of intersection, 26-inch abandonment cap ROW 21-Cropland and p

Road crossing, wetland crossing, pipe/equipment staging, turnaround area

62-Nonforested we14-Transportation, 42-Evergreen fores62-Nonforested we

7 Mt Vernon South 1439.45 Wetland crossings AR 706 42-Evergreen fores

62-Nonforested we14-Transportation, 

7 Mt Vernon South 1439.96 wetland crossings AR 708 21-Cropland and p

7 Mt Vernon South 1440.01 wetland crossings ROW 21-Cropland and p

7 Mt Vernon South 1440.03 wetland crossings, removal of existing pipe, points of intersection, 26-

inch abandonment cap

ROW 21-Cropland and p

7 Mt Vernon South 1439.44 Wetland crossings AR 706

7 Mt Vernon South 1439.69 Passing lane, parking, wetland crossings AR 707

AR 703.1/AR 704

Hilly terrain, side slope, parking, turnaround area, timber storage, wetland crossings

7 Mt Vernon South 1438.42

Gunderson Road

7 Mt Vernon South 1439.32

7 Mt Vernon South 1436.91 Passing lane, hilly terrain, side slope Crestwood Dr

7 Mt Vernon South 1437.18 Passing lane, parking ROW

7 Mt Vernon South 1436.36 AR 700

7 Mt Vernon South 1436.81 Access to hydrotest water Stonewood Dr

Lake Cavanaugh Road

7 Mt Vernon South 1435.79 Passing lane, hilly terrain, side slope

I4-20
Loop 

Number Loop Name ATWS ID Description/Justificationa Access Land Use Cod

Appendix I4

Additional Temporary Workspace for the Pipeline Route

21-Cropland and p62-Nonforested we14-Transportation, 

8 Mt Vernon North A 1440.39 Waterbody crossing, hydrotest water access and discharge ROW 21-Cropland and p

8 Mt Vernon North A 1440.45 Waterbody crossing, hydrotest water access and discharge ROW 21-Cropland and p

8 Mt Vernon North A 1440.60 Existing Northwest Pipeline facility, road crossing, parking Beaver Lake 

Road

14-Transportation, 

8 Mt Vernon North A 1441.55 wetland crossings, road crossing, turnaround area, parking, staging ROW 21-Cropland and p8 Mt Vernon North A 1442.75 Steep terrain, wetland crossing, timber storage, point of intersection, 

parking, turnaround area

ROW 14-Transportation, 

8 Mt Vernon North A 1442.82 Steep terrain, removal of existing pipe, timber storage, pipe/equipment 

staging, hydrotest 

AR 801.1 21-Cropland and p

8 Mt Vernon North A 1443.59 Steep terrain, timber removal, removal of existing pipe, hydrotest ROW 42-Evergreen fores8 Mt Vernon North A 1443.90 Steep terrain, timber removal, removal of existing pipe ROW 42-Evergreen fores

42-Evergreen fores14-Transportation, 

8 Mt Vernon North A 1444.81 Steep terrain, points of intersection, valve installation, demobilization, tiein to existing span AR 804 42-Evergreen fores

8 Mt Vernon North A 1444.83 Steep terrain, points of intersection, valve installation, demobilization, tiein to existing span, hydrotest AR 804 42-Evergreen fores

21-Cropland and p14-Transportation, 21-Cropland and p14-Transportation, 11-Residential 14-Transportation, 

9 Mt Vernon North B 1454.08 Parking, turnaround area Cruse Road 14-Transportation, 9 Mt Vernon North B 1454.12 Wetland crossings, parking, turnaround area Cruse Road 14-Transportation, 

41-Deciduous fores14-Transportation, 

9 Mt Vernon North B 1454.81 Stream crossing, timber storage, parking, staging ROW 11-Residential 

9 Mt Vernon North B 1454.04 Cross-over Cruse Road

9 Mt Vernon North B 1454.31 Wetland crossings, parking, turnaround area Cruse Road

Existing Northwest Pipeline facility, aboveground facility removal, AR 805demobilization, tie-in to existing span, hydrotest

8 Mt Vernon North A 1444.99

Existing Northwest Pipeline facility, aboveground facility removal, AR 900mobilization, pipe/equipment staging, road crossing, hydrotest

9 Mt Vernon North B 1453.53

Existing Northwest Pipeline facility, mobilization/demobilization, removal Lange Roadof existing pipe, aboveground facilities installation, pipe/equipment staging

7 Mt Vernon South 1440.17

8 Mt Vernon North A 1444.15 Steep terrain, pipe/equipment staging AR 803

I4-21
Loop 

Number Loop Name ATWS ID Description/Justificationa Access Land Use Cod

Appendix I4

Additional Temporary Workspace for the Pipeline Route

ROW 41-Deciduous fores

61-Forested wetlan

9 Mt Vernon North B 1455.48 Pipeline crossover, timber storage, staging ROW 43-Mixed forest lan9 Mt Vernon North B 1456.55 Removal of existing pipe, timber storage, pipe/equipment staging, valve 

installation

AR 901/AR 902 

42-Evergreen fores21-Cropland and p43-Mixed forest lan

9 Mt Vernon North B 1458.21 Removal of existing pipe, pipe/equipment staging, timber storage AR 904.1 43-Mixed forest lan

21-Cropland and p43-Mixed forest lan21-Cropland and p62-Nonforested we

9 Mt Vernon North B 1459.57 Road crossing, pipe/equipment staging Saxon Road 21-Cropland and p

21-Cropland and p14-Transportation, 

9 Mt Vernon North B 1459.87 Removal of existing pipe, pipe/equipment staging, road crossing, 

wetland staging

Maleng Road 21-Cropland and p

21-Cropland and p14-Transportation, 

9 Mt Vernon North B 1461.19 Road crossing, HDD equipment, extra pipe for HDD 2nd weld Rothenbuhler 

Road

21-Cropland and p21-Cropland and p62-Nonforested we21-Cropland and p62-Nonforested we51-Streams and ca

14-Transportation, 21-Cropland and p62-Nonforested we51-Streams and ca

21-Cropland and p43-Mixed forest lan14-Transportation, 

10 Sumas 1478.58 Existing Northwest Pipeline facility, mobilization, pipe/equipment staging, 

d i hd t t

Leibrant Road 21-Cropland and p

10 Sumas 1478.58 Existing Northwest Pipeline facility, mobilization, aboveground facility 

installation, pipe/equipment staging, road crossing, hydrotest

Leibrant Road 14-Transportation, 

10 Sumas 1479.19 Removal of existing pipe, pipe/equipment staging AR 1000 21-Cropland and p

9 Mt Vernon North B 1461.46 Hydrotest water access ROW

Mosquito Lake Road

Existing Northwest Pipeline Facility, demobilization, hydrotest, waterbody crossing, HDD Entry, aboveground facility removal

9 Mt Vernon North B 1461.80

Rothenbuhler Road

9 Mt Vernon North B 1461.21 HDD pullback, road crossing

Rothenbuhler Road

HDD pullback, HDD equipment, removal of existing pipe, 26-inch abandonment cap

9 Mt Vernon North B 1461.30

Saxon Road/Lay Road

9 Mt Vernon North B 1459.62 Road crossing, pipe/equipment staging

Rothenbuhler Road

9 Mt Vernon North B 1461.17 HDD pullback

9 Mt Vernon North B 1458.60 wetland crossing, point of intersection ROW

Removal of existing pipe, pipe/equipment staging, wetland crossings, Doren Roadroad crossing

9 Mt Vernon North B 1458.90

9 Mt Vernon North B 1455.23 Pipeline crossover, timber storage

Removal of existing pipe, timber storage, pipe/equipment staging, AR 903stream crossing

9 Mt Vernon North B 1457.44

I4-22
Loop 

Number Loop Name ATWS ID Description/Justificationa Access Land Use Cod

Appendix I4

Additional Temporary Workspace for the Pipeline Route

10 Sumas 1480.61 Removal of existing pipe, timber storage, pipe/equipment staging AR 1002 43-Mixed forest lan

21-Cropland and p14-Transportation, 21-Cropland and p14-Transportation, 21-Cropland and p14-Transportation, 

Reese Hill Road

21-Cropland and p43-Mixed forest lan

10 Sumas 1482.82 Waterbody crossing, road crossing ROW 21-Cropland and p

21-Cropland and p14-Transportation, 

10 Sumas 1483.05 Waterbody crossing ROW 21-Cropland and p10 Sumas 1483.08 Waterbody crossing ROW 21-Cropland and p10 Sumas 1483.86 Road crossing, removal of existing pipe, pipe/equipment staging Rock Road 21-Cropland and p

21-Cropland and p

62-Nonforested we

11-Residential 14-Transportation, 21-Cropland and p14-Transportation, 

10 Sumas 1484.48 Existing Northwest Pipeline facility, mobilization/demobilization, pipe 

stockpile, aboveground facility installation, hydrotest, removal of existing pipe

Jones Road 14-Transportation, 

Existing Northwest Pipeline facility, mobilization/demobilization, pipe Jones Roadstockpile, removal of existing pipe

10 Sumas 1484.3210 Sumas 1482.96 Road crossing, removal of existing pipe, pipe/equipment staging Hillview Road

Existing Northwest Pipeline facility, mobilization/demobilization, pipe Jones Roadstockpile, removal of existing pipe

10 Sumas 1484.3010 Sumas10 Sumas 1482.78 Waterbody crossing

1481.47 Removal of existing pipe, pipe/equipment staging, road crossing Minaker Road

1481.55 Road crossing Minaker Rd

10 Sumas10 Sumas 1481.51 Road crossing Minaker Road

b Amounts showing as 0.00 indicate a fractional amount less than two decimal places. However, these values are included in TEWA totals presented on the Alig

 Revised Appendix 1C of Revised Resource Report 1—General Project Description. 

c ROW = right-of-waya Only major hydrotest sources and discharge TEWAs are identified on the Alignment Sheets provided in Revised Appendix 1C of Revised Resource Report 1—

I4-23

APPENDIX I5 

TABLE OF ACCESS ROADS

Access # Milepost

Length

(Miles)

Approximate 

Width

(Feet) Road Name Surfacing Road Statusd

Woodland 

100 1244.29 0.86 24 Insel Road Asphalt Existing Permanent

100.1 1244.29 0.06 20 Insel Road Extension Gravel Future Permanent

100.2 1244.60 0.06 20 Bozarth Heights Road Gravel Existing Permanent

101 1245.10 1.07 24 Hillsdale Drive Asphalt Existing Permanent

101.1 1245.01 0.01 24 Insel Road Asphalt Existing Permanent

102 1245.65 0.15 24 Fairwood Road Asphalt Existing Permanent

103 1246.17 0.30 24 Pompano Road/Runyan Road Asphalt Existing Permanent

103.1 1246.20 0.01 24 No Name Asphalt Existing Permanent

104 1246.53 0.20 20 No Name Gravel Existing Permanent

105 1246.98 0.11 24 No Name Asphalt Temporary

106 1247.32 0.72 24 Varsity Road Asphalt Existing Permanent

107 1248.43 0.19 20 No Name Gravel Existing Permanent

108 1248.90 0.05 20 No Name Gravel Temporary

109 1249.20 0.16 12 No Name Two Track Temporary

109.1 1249.08 0.06 20 No Name Gravel Temporary

110 1250.44 4.88 20 JE Johnson Road Gravel Existing Permanent

111 1251.65 1.01 20 No Name Gravel Future Permanent

111.1 1251.79 0.36 12 No Name Two Track Existing Permanent

112 1252.71 1.04 24 Faber Road Asphalt Existing Permanent

112.1 1252.46 0.43 24 No Name Asphalt Existing Permanent

113 1252.94 0.29 12 Lady Blue Lane Two Track Existing Permanent

114 1253.40 0.57 20 Bates Road Gravel Existing Permanent

115 1253.55 0.30 12 No Name Two Track Existing Permanent

115.1 1253.97 0.99 12 No Name Two Track Existing Permanent

116 1254.51 0.74 12 No Name Two Track Existing Permanent

116.1 1254.22 0.27 12 No Name Two Track Existing Permanent

117 1256.58 0.16 12 No Name Two Track Existing Permanent

118 1257.19 0.11 12 No Name Two Track Existing Permanent

119 1257.78 0.33 24 Owl Creek Road Asphalt Existing Permanent

120 1258.21 0.03 24 Ranch Road Asphalt Existing Permanent

121 1258.93 2.03 20 Walker Road Gravel Existing Permanent

121.1 1258.79 0.17 24 Wildlife Drive Asphalt Existing Permanent

122 1260.13 0.57 12 No Name Two Track Existing Permanent

122.1 1260.47 0.06 12 No Name Two Track Existing Permanent

122.2 1260.51 0.07 12 No Name Two Track Existing Permanent

123 1261.40 0.70 24 Harris Street Asphalt Existing Permanent

124 1263.67 0.50 12 No Name Two Track Existing Permanent

125 1264.84 1.23 12 No Name Two Track Existing Permanent

125.1 1264.69 0.13 12 No Name Two Track Existing Permanent

126 1265.19 0.20 20 No Name Gravel Existing Permanent

126.1 1265.15 0.12 20 No Name Gravel Existing Permanent

127 1265.49 0.74 12 No Name Two Track Existing Permanent

127.1 1265.69 0.19 12 No Name Two Track Existing Permanent

127.2 1265.80 0.01 12 No Name Two Track Existing Permanent

128 1266.22 0.12 12 Walnut Acres Road Two Track Existing Permanent

129 1267.82 0.20 12 No Name Two Track Existing Permanent

130 1268.46 0.38 20 No Name Gravel Existing Permanent

131 1269.23 0.09 20 No Name Gravel Existing Permanent

132 1269.38 0.06 12 No Name Two Track Existing Permanent

Appendix I5

Table of Access Roads

Washington Expansion Project Access Roads a, b, c

I5-1
Access # Milepost

Length

(Miles)

Approximate 

Width

(Feet) Road Name Surfacing Road Statusd

Appendix I5

Table of Access Roads

Washington Expansion Project Access Roads a, b, c

133 1269.48 0.12 24 Kalmbach Road Asphalt Existing Permanent

134 1272.18 2.04 12 No Name Two Track Existing Permanent

134.1 1270.76 0.04 12 No Name Two Track Existing Permanent

134.2 1271.25 0.41 12 No Name Two Track Existing Permanent

134.3 1271.62 0.25 12 No Name Two Track Existing Permanent

134.4 1271.98 0.10 12 No Name Two Track Existing Permanent

135 1272.61 0.11 12 No Name Two Track Existing Permanent

136 1272.71 1.44 20 Kroll Road Gravel Existing Permanent

136.1 1273.49 0.13 12 No Name Two Track Existing Permanent

136.2 1274.10 0.19 24 No Name Asphalt Existing Permanent

136.3 1274.21 0.59 12 No Name Two Track Existing Permanent

137 1276.65 4.06 20 Burma Road Gravel Existing Permanent

137.1 1274.77 0.90 30 Toutle Park Road Gravel Existing Permanent

137.2 1275.94 1.05 20 No Name Gravel Existing Permanent

137.3 1276.15 0.11 12 No Name Two Track Existing Permanent

137.4 1276.33 0.82 20 No Name Gravel Existing Permanent

137.5 1277.44 0.07 12 No Name Two Track Existing Permanent

138 1278.96 1.48 20 No Name Gravel Existing Permanent

138.1 1278.37 0.77 20 No Name Gravel Existing Permanent

138.2 1278.61 0.22 20 No Name Gravel Existing Permanent

139 1279.57 1.35 20 No Name Gravel Existing Permanent

139.1 1279.84 0.20 20 No Name Gravel Existing Permanent

140 1281.21 0.07 20 No Name Gravel Existing Permanent

141 1281.38 0.57 24 Herriford Road / Mandy Road Asphalt Existing Permanent

141.1 1282.20 0.89 24 Shoreline Drive Asphalt Existing Permanent

141.2 1281.82 0.05 24 No Name Asphalt Existing Permanent

142 1282.74 0.67 24 Bill Creek Road Asphalt Temporary

143 1285.37 0.07 12 No Name Two Track Existing Permanent

144 1286.30 0.28 20 Campground Lane Gravel Existing Permanent

145 1287.12 0.18 12 No Name Two Track Existing Permanent

146 1287.69 0.30 20 Florence Place Gravel Existing Permanent

147 1288.69 0.35 12 No Name Two Track Existing Permanent

148 1289.44 0.35 24 Meier Road West Asphalt Existing Permanent

Chehalis

200 1291.46 0.16 12 No Name Two Track Temporary

201 1291.70 0.34 12 No Name Two Track Existing Permanent

202 1292.75 0.08 20 No Name Gravel Temporary

203 1293.59 0.30 12 No Name Two Track Future Permanent

204 1294.04 0.58 24 Pier Road Asphalt Existing Permanent

205 1294.52 0.19 24 Taylor Road South Asphalt Temporary

206 1294.87 0.06 20 No Name Gravel Existing Permanent

207 1295.80 0.14 24 Yates Road Asphalt Existing Permanent

208 1296.30 0.24 24 Ryan Drive Asphalt Existing Permanent

209 1297.16 0.22 20 Mountain Sun Road Gravel Existing Permanent

210 1297.85 0.31 12 No Name Two Track Temporary

211 1299.48 0.97 12 No Name Two Track Future Permanent

211.1 1299.64 0.10 12 No Name Two Track Future Permanent

212 1300.33 0.88 24 Reinke Road Asphalt Future Permanent

212.1 1300.00 0.14 12 No Name Two Track Existing Permanent

212.2 1300.09 0.11 12 No Name Two Track Temporary

I5-2
Access # Milepost

Length

(Miles)

Approximate 

Width

(Feet) Road Name Surfacing Road Statusd

Appendix I5

Table of Access Roads

Washington Expansion Project Access Roads a, b, c

213 1301.21 0.41 12 No Name Two Track Existing Permanent

214 1302.23 1.67 12 Anderson Road Two Track Existing Permanent

214.1 1301.93 0.11 12 No Name Two Track Existing Permanent

214.2 1302.81 1.18 20 No Name Gravel Existing Permanent

215 1303.78 0.73 12 No Name Two Track Existing Permanent

216 1304.29 1.46 20 No Name Gravel Existing Permanent

216.1 1304.77 0.65 12 No Name Two Track Existing Permanent

216.2 1305.31 1.02 20 No Name Gravel Existing Permanent

217 1306.85 0.19 20 Elkview Lane Gravel Existing Permanent

218 1308.04 3.67 20 Thompson Creek Road SE Gravel Existing Permanent

218.1 1307.27 1.25 20 No Name Gravel Existing Permanent

218.2 1307.81 0.05 12 No Name Two Track Existing Permanent

218.3 1308.10 0.05 12 No Name Two Track Existing Permanent

218.4 1308.57 0.22 12 No Name Two Track Existing Permanent

219 1309.65 0.25 12 No Name Two Track Temporary

220 1309.80 0.02 20 No Name Gravel Temporary

221 1310.16 5.86 12 No Name Two Track Existing Permanent

221.1 1310.30 0.06 12 No Name Two Track Existing Permanent

221.2 1312.77 0.75 20 No Name Gravel Existing Permanent

221.3 1313.22 1.05 12 No Name Two Track Existing Permanent

221.4 1313.48 0.11 12 No Name Two Track Existing Permanent

222 1310.84 1.56 12 No Name Two Track Temporary

223 1314.11 1.91 20 No Name Gravel Existing Permanent

224 1314.76 3.40 20 NF-900 Gravel Existing Permanent

225 1315.60 0.27 12 160th Lane SE Two Track Existing Permanent

Sumner South

300 1339.96 0.56 20 No Name Gravel Existing Permanent

301 1340.44 0.46 24 70th Avenue East / 164th Street East Asphalt Existing Permanent

302 1340.52 0.17 20 74th Avenue East Gravel Existing Permanent

302.1 1340.58 0.07 20 No Name Gravel Temporary

302.2 1340.69 0.06 20 No Name Gravel Existing Permanent

303 1341.05 0.08 20 No Name Gravel Temporary

304 1341.22 0.42 24 74th Avenue E / 152nd Street East Asphalt Existing Permanent

305 1342.59 0.17 24 137th Street East Asphalt Existing Permanent

306 1344.82 0.10 24 10th Street SE Asphalt Existing Permanent

307 1344.96 0.21 24 No Name Asphalt Existing Permanent

308 1347.14 0.15 20 No Name Gravel Temporary

309 1347.38 0.10 24 134th Avenue East Asphalt Existing Permanent

310 1347.84 0.12 12 No Name Two Track Temporary

311 1348.10 0.45 24 143rd Avenue East / Rivergrove Drive East Asphalt Existing Permanent

311.1 1348.17 0.14 24 Village Drive East Asphalt Existing Permanent

311.2 1348.25 0.16 24 72nd St E / 74th St Ct East Asphalt Existing Permanent

312 1348.31 0.03 12 No Name Two Track Temporary

313 1348.54 0.29 24 74th Street East / Riverside Road East Asphalt Existing Permanent

314 1349.28 0.06 20 No Name Gravel Future Permanent

Sumner North A

400 1357.07 0.26 12 144th Avenue SE Two Track Existing Permanent

401 1357.49 0.21 12 No Name Two Track Existing Permanent

402 1358.79 0.01 12 No Name Two Track Existing Permanent

404 1359.91 0.02 12 No Name Two Track Existing Permanent

405 1360.05 0.16 12 No Name Two Track Temporary

I5-3
Access # Milepost

Length

(Miles)

Approximate 

Width

(Feet) Road Name Surfacing Road Statusd

Appendix I5

Table of Access Roads

Washington Expansion Project Access Roads a, b, c

406 1360.47 0.16 12 No Name / 176th Avenue SE Two Track Existing Permanent

407 1360.61 0.14 12 SE 303rd Street Asphalt Existing Permanent

408 1361.05 0.09 20 SE 299th Place Gravel Temporary

409 1361.55 0.04 20 No Name Gravel Existing Permanent

410 1361.65 0.05 12 186th Place SE Two Track Existing Permanent

411 1361.80 0.42 12 184th Place SE / SE 287th Street Two Track Existing Permanent

412 1362.78 0.03 12 No Name Two Track Existing Permanent

413 1363.89 0.04 20 No Name Gravel Existing Permanent

Sumner North B

500 1370.89 0.01 20 No Name Gravel Existing Permanent

501 1371.18 0.17 20 No Name Gravel Temporary

502 1371.30 0.10 20 SE 148th Place Gravel Existing Permanent

502.1 1371.45 0.15 20 23Road Avenue SE Gravel Existing Permanent

503 1372.00 0.03 20 SE 137th Street Gravel Existing Permanent

504 1372.62 0.09 20 SE 127th Street Gravel Existing Permanent

505 1372.76 0.05 20 SE 125th Place Gravel Existing Permanent

506 1372.83 0.03 24 No Name Asphalt Existing Permanent

507 1372.89 0.01 24 No Name Asphalt Temporary

508 1373.05 0.01 20 No Name Gravel Temporary

509 1373.68 0.18 24 SE 111th Street Asphalt Existing Permanent

510 1373.99 0.24 20 SE 106th Place Gravel Existing Permanent

511 1374.23 0.19 20 SE 103Road Street Gravel Existing Permanent

512 1375.64 1.41 20 SE 79th Street Gravel Existing Permanent

513 1376.84 0.07 20 No Name Gravel Temporary

514 1377.43 0.32 20 No Name Gravel Temporary

515 1380.13 0.47 24 245th Avenue SE / 244th Avenue SE / 242nd Avenue SAsphalt Existing Permanent

517 1381.57 0.51 24 237th Place NE / NE 5th Street / 242nd Avenue NE Asphalt Existing Permanent

518 1381.88 0.15 24 238th Avenue NE Asphalt Existing Permanent

518.1 1381.82 0.01 12 No Name Two Track Existing Permanent

Snohomish

600 1394.18 0.07 24 No Name Asphalt Temporary

601 1395.69 0.03 20 No Name Gravel Existing Permanent

602 1396.60 0.05 24 No Name Asphalt Existing Permanent

603 1397.95 0.17 20 Tester Branch Road / No Name Gravel Existing Permanent

603.1 1398.01 0.28 20 No Name Gravel Existing Permanent

604 1400.61 0.09 20 No Name Gravel Existing Permanent

605 1401.59 1.51 20 No Name Gravel Existing Permanent

606 1402.89 0.05 20 No Name Gravel Existing Permanent

607 1402.94 0.01 20 No Name Gravel Existing Permanent

608 1403.75 0.08 20 84th Street SE Gravel Existing Permanent

609 1405.09 0.10 20 No Name Gravel Existing Permanent

610 1406.19 0.11 20 No Name Gravel Existing Permanent

611 1407.02 0.07 20 No Name Gravel Existing Permanent

612 1407.25 0.04 20 No Name Gravel Existing Permanent

613 1408.53 0.13 24 12th Street SE Asphalt Existing Permanent

614 1408.60 0.13 20 No Name Gravel Existing Permanent

615 1408.75 0.12 20 No Name Gravel Existing Permanent

Mt. Vernon South

700 1435.70 0.61 20 No Name Gravel Existing Permanent

701 1437.64 0.18 20 Walker Valley Road Gravel Existing Permanent

702 1437.75 0.03 24 No Name Asphalt Existing Permanent

I5-4
Access # Milepost

Length

(Miles)

Approximate 

Width

(Feet) Road Name Surfacing Road Statusd

Appendix I5

Table of Access Roads

Washington Expansion Project Access Roads a, b, c

703 1437.90 0.13 20 No Name Gravel Existing Permanent

703.1 1438.20 0.36 20 No Name Gravel Existing Permanent

704 1438.41 0.74 20 No Name Gravel Temporary

705 1439.13 0.01 20 No Name Gravel Temporary

706 1439.46 0.04 20 No Name Gravel Temporary

707 1439.59 0.17 20 No Name Gravel Temporary

708 1439.97 0.04 20 No Name Gravel Existing Permanent

Mt. Vernon North A

800 1442.14 0.52 20 Fox Road Gravel Existing Permanent

801 1442.89 0.17 20 No Name Gravel Existing Permanent

801.1 1442.83 0.03 20 No Name Gravel Existing Permanent

802 1443.14 0.09 20 No Name Gravel Existing Permanent

803 1444.13 0.57 20 Morford Road Gravel Existing Permanent

804 1444.83 0.05 20 No Name Gravel Existing Permanent

805 1444.99 0.30 20 River Lane Gravel Existing Permanent

Mt. Vernon North B

900 1453.55 0.22 20 Duvall Drive Gravel Existing Permanent

901 1456.81 0.39 20 No Name Gravel Temporary

902 1456.61 0.39 20 Pacific Northwest Trail Gravel Existing Permanent

903 1457.47 0.15 20 No Name Gravel Temporary

904 1457.67 0.46 20 No Name Gravel Existing Permanent

904.1 1458.24 0.84 20 No Name Gravel Existing Permanent

905 1459.65 0.03 20 No Name Gravel Existing Permanent

906 1461.03 0.37 20 No Name Gravel Temporary

Sumas

1000 1479.19 0.13 20 No Name Gravel Temporary

1001 1480.20 0.57 20 No Name Gravel Existing Permanent

1002 1480.59 0.34 20 No Name Gravel Temporary

1003 1481.61 0.08 20 No Name Gravel Existing Permanent

NE= northeast

SE= southeast

Note

a

b

c

d

Purpose

Safety

Terrain

Traffic

Explanation

It is necessary to provide sufficient access for emergency vehicles. The pipeline crosses many locations along 

the right-of-way (ROW) that emergency vehicles would not be able to travel, and the ability to get emergency 

vehicles into the ROW requires several access points.

The pipeline crosses several locations along the ROW that construction vehicles would not be able to access, 

including areas with steep terrain, gorges, creeks, or rivers. Additionally, in order to minimize construction 

impacts, the ROW is narrow and has multiple side slopes. This type of terrain requires access points for pipe 

trucks to enter at one end of a construction site and leave at the opposite end. There is limited space for two-way 

traffic along the construction site and there are minimal turnaround locations for long equipment such as pipe 

trucks and trailers.

During construction, multiple construction tasks will occur concurrently, including removal of existing 26-inch 

pipe, delivery of new pipe, timber removal, and dust control operations, and will necessitate continual site access 

for construction vehicles and equipment.

Existing Permanent: Existing roads used currently and in the past by Northwest operations personnel for ROW, 

I5-5