Appendix B—Transmission Line
and Substation Components
Prepared by:
Idaho Power Company
1221 W Idaho Street
Boise, ID 83702
November 2011
Transmission Line and Substation Components
Appendix B
1
TABLE OF CONTENTS
2
1.0 PROJECT FACILITIES ........................................................................................................ 1
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
1.1 Transmission Structures.............................................................................................. 1
1.1.1 Types of Transmission Line Support Structures .............................................. 1
1.1.2 Structure and Conductor Clearances .............................................................. 8
1.1.3 Structure Foundations ..................................................................................... 8
1.2 Conductors .................................................................................................................. 9
1.3 Other Hardware ......................................................................................................... 10
1.3.1 Insulators ....................................................................................................... 10
1.3.2 Grounding Systems ....................................................................................... 10
1.3.3 Minor Additional Hardware ............................................................................ 11
1.4 Communication Systems........................................................................................... 12
1.4.1 Optical Ground Wire ...................................................................................... 12
1.4.2 Communications Stations .............................................................................. 12
1.5 Access Roads ........................................................................................................... 13
1.6 Substations................................................................................................................ 21
1.6.1 Substation Components ................................................................................ 21
1.6.2 Distribution Supply Lines ............................................................................... 22
19
2.0 SYSTEM CONSTRUCTION .............................................................................................. 23
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21
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24
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26
27
28
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31
32
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34
35
36
37
38
39
40
41
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43
44
45
46
47
48
2.1 Land Requirements and Disturbance ........................................................................ 23
2.1.1 Right-of-Way Width ....................................................................................... 23
2.1.2 Right-of-Way Acquisition ............................................................................... 25
2.1.3 Land Disturbance .......................................................................................... 26
2.2 Transmission Line Construction ................................................................................ 32
2.2.1 Transmission Line System Roads ................................................................. 32
2.2.2 Soil Borings ................................................................................................... 34
2.2.3 Staging Areas ................................................................................................ 34
2.2.4 Site Preparation ............................................................................................. 35
2.2.5 Install Structure Foundations ......................................................................... 35
2.2.6 Erect Support Structures ............................................................................... 36
2.2.7 String Conductors, Shield Wire, and Fiber Optic Ground Wire ..................... 37
2.2.8 Cleanup and Site Reclamation ...................................................................... 39
2.3 Communication System ............................................................................................ 39
2.3.1 Communication Sites ..................................................................................... 39
2.3.2 Access Road ................................................................................................. 39
2.4 Substation Construction ............................................................................................ 39
2.4.1 Substation Roads .......................................................................................... 40
2.4.2 Soil Borings ................................................................................................... 40
2.4.3 Clearing and Grading .................................................................................... 40
2.4.4 Storage and Staging Yards ........................................................................... 40
2.4.5 Grounding ...................................................................................................... 40
2.4.6 Fencing .......................................................................................................... 40
2.4.7 Foundation Installation .................................................................................. 41
2.4.8 Oil Containment ............................................................................................. 41
2.4.9 Structure and Equipment Installation............................................................. 41
2.4.10 Conduit and Control Cable Installation .......................................................... 42
2.4.11 Construction Cleanup and Landscaping ........................................................ 42
2.5 Special Construction Techniques .............................................................................. 42
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2
3
4
5
6
7
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2.5.1 Blasting .......................................................................................................... 42
2.5.2 Helicopter Use ............................................................................................... 44
2.5.3 Water Use...................................................................................................... 45
2.6 Construction Elements .............................................................................................. 45
2.6.1 Construction Workforce ................................................................................. 46
2.6.2 Construction Equipment and Traffic .............................................................. 47
2.6.3 Removal of Facilities and Waste Disposal .................................................... 50
2.6.4 Construction Schedule .................................................................................. 50
9
3.0 SYSTEM OPERATIONS AND MAINTENANCE ................................................................ 54
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3.1 Routine System Operations and Maintenance .......................................................... 54
3.1.1 Routine System Inspection, Maintenance, and Repair .................................. 54
3.1.2 Transmission Line Maintenance .................................................................... 55
3.1.3 Hardware Maintenance and Repairs ............................................................. 57
3.1.4 Access Road and Work Area Repair ............................................................. 60
3.1.5 Vegetation Management ............................................................................... 60
3.1.6 Noxious Weed Control................................................................................... 62
3.1.7 Substation and Communication Site Maintenance ........................................ 62
3.2 Emergency Response ............................................................................................... 63
3.2.1 Fire Protection ............................................................................................... 63
20
4.0 DECOMMISSIONING ........................................................................................................ 65
21
LIST OF TABLES
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35
36
37
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39
Table 1-1.
Table 1-2.
Table 1-3.
Table 1-4.
Table 2-1.
Table 2-2.
Table 2-3.
Table 2-4.
Table 2-5.
Table 2-6.
Table 2-7.
Table 2-8.
Table 2-9.
Table 2-10.
Table 2-11.
Table 2-12.
Proposed Structure Characteristics .................................................................. 8
Foundation Excavation Dimensions ................................................................. 9
Proposed Communications Station Locations ................................................ 12
Access Road Requirements for Transmission Line System ........................... 14
Summary of Land Required for Construction and Operations ........................ 23
Summary of Land Disturbed during Construction and Used during Permanent
Operations ...................................................................................................... 26
Miles of New and Improved off-ROW Access Roads ..................................... 33
Miles of New and Improved Access Roads1 ................................................... 34
Construction Staging Areas and Helicopter Fly Yards .................................... 35
Summary of Shallow Bedrock ......................................................................... 43
Estimated Water Usage for Construction by County ...................................... 45
Projected Workers and Population Change during Peak Construction .......... 46
Transmission Line Construction Equipment Requirements ............................ 47
Equipment Requirements for Grassland and Hemingway Substations .......... 48
Average and Peak Construction Traffic (per spread) ..................................... 49
Solid Waste Generation from Construction Activities ..................................... 50
40
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Appendix B
LIST OF FIGURES
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Figure 1-1.
Figure 1-2.
Figure 1-3.
Figure 1-4.
Figure 1-5.
Figure 1-6.
Figure 1-7.
Figure 1-8.
Figure 1-9.
Figure 1-10.
Figure 1-11.
Figure 1-12.
Figure 2-1.
Figure 2-2.
Figure 2-3.
Figure 2-4.
Figure 2-5.
Figure 2-6.
Figure 3-1. Figure 3-2.
November 2011
Proposed 500-kV Single Circuit Lattice Steel Structure ................................... 2
Proposed 500-kV Single Circuit Tubular Steel Pole H-frame Structure ............ 3
Proposed 138/69-kV Double Circuit Structure with Distribution Underbuild ..... 4
Proposed ROW Designs................................................................................... 5
Alternative 500-kV Single Shaft Steel Pole Structure ....................................... 6
Alternative ROW Design ................................................................................... 7
Typical Communication Site ........................................................................... 13
Typical Road Sections for Different Terrains .................................................. 15
Type 1 Drive Through Stream Crossing Methods .......................................... 16
Type 2 and Type 3 Crossing Methods ............................................................ 18
Type 4 – Channel Spanning Structures Including Fish Passage .................... 19
Typical 500-kV Substation .............................................................................. 22
Disturbance Area for Tower Structures .......................................................... 29
Typical Disturbance Area................................................................................ 30
Example Access Roads and Tower Locations ............................................... 31
Transmission Line Construction Sequence .................................................... 32
Conductor Installation ..................................................................................... 37
Project Construction Schedule ....................................................................... 52
Live-line Maintenance Space Requirements, Single-Circuit 500-kV Lattice
Tower .............................................................................................................. 59
Right-of-Way Vegetation Management ........................................................... 61
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Appendix B
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3
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This appendix contains detailed information provided by Idaho Power Company (IPC) regarding
the components of the transmission system including the transmission structures, the
communications system, and the substations. It provides details regarding construction of the
system (Section 2.0), goes on to provide information regarding the operations and maintenance
of the system (Section 3.0), and finally details the proposed abandonment and restoration
techniques (Section 4.0).
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1.0
PROJECT FACILITIES
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9
10
11
12
This section describes the various components of the transmission system for the Boardman to
Hemingway Transmission Line Project (Boardman to Hemingway or Project), including the
structures themselves, the conductors used, other hardware needed, the communication
system, the access roads, and finally the substations. Both the proposed and alternative
structures are described herein
13
1.1 Transmission Structures
14
1.1.1 Types of Transmission Line Support Structures
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The majority of the proposed transmission line circuits will be supported by steel single-circuit
steel lattice towers. Figure 1-1 illustrates the typical tangent lattice tower structure configuration.
In some instances, single-circuit tubular steel H-frame structures will be used where required to
mitigate sensitive environmental resources or where land use requires shorter structure heights.
Figure 1-2 illustrates a tangent tubular steel H-frame structure. Figure 1-3 provides an
illustration of a typical 138/68-kilovolt (kV) structure with 12.5-kV underbuild distribution that
1
would be used for approximately 5.3 miles.
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25
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Tangent structures are primarily used in straight line segments and are the most common type
of structure. Running angles are used when a transmission line changes direction up to a
specified threshold line angle. Dead-end structures are needed for extremely long spans, when
the line angle exceeds the threshold of a running angle tower, in highly varied terrain which can
create uplift conditions, or when there is a need for a failure containment structure. Angle and
dead-end structures are heavier and require larger foundations.
28
Figure 1-4 illustrates the right-of-way (ROW) design configurations for proposed structures.
29
1
Of the 5.3 miles, 0.3 miles would be a 138-kV single-circuit which because of its limited extent, is not further discussed in this
document.
November 2011
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Transmission Line and Substation Components
Appendix B
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Figure 1-1.
Proposed 500-kV Single Circuit Lattice Steel Structure
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November 2011
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Transmission Line and Substation Components
Appendix B
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2
Figure 1-2.
Proposed 500-kV Single Circuit Tubular Steel Pole H-frame Structure
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November 2011
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Appendix B
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2
3
4
Figure 1-3.
November 2011
Proposed 138/69-kV Double Circuit Structure with Distribution
Underbuild
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Transmission Line and Substation Components
Appendix B
1
2
Figure 1-4.
Proposed ROW Designs
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November 2011
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Transmission Line and Substation Components
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2
3
Appendix B
Figure 1-5 presents the configuration of the alternative 500-kV monopole structure which could
be used in active agricultural areas where location is critical to farming operations. Figure 1-6
illustrates the alternative ROW design configuration.
4
5
Figure 1-5.
November 2011
Alternative 500-kV Single Shaft Steel Pole Structure
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Transmission Line and Substation Components
Appendix B
1
2
Figure 1-6.
Alternative ROW Design
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1.1.1.1 Proposed 500-kV Single Circuit Galvanized Lattice Steel Structures
Lattice steel towers will be fabricated with galvanized steel members treated to produce a dulled
galvanized finish. The average distance between 500-kV towers will be 1,200 to 1,300 feet.
Structure heights will vary depending on terrain and the requirement to maintain minimum
conductor clearances from ground. The 500-kV single-circuit towers will vary in height from 110
to 195 feet.
1.1.1.2 Proposed 500-kV Single Circuit Tubular Steel H-Frame Structures
The 500-kV H-frame structures will be fabricated with self-weathering tubular steel treated to
produce a rust-like finish. The average distance between 500-kV H-frames will be 1,200 to
1,300 feet. Structure heights will vary depending on terrain and the requirement to maintain
minimum conductor clearances from ground. The 500-kV H-frame structures will vary in height
from 100 to 165 feet.
1.1.1.3 Proposed 138/69-kV Double Circuit Galvanized Monopole Structures
Monopole structures will be fabricated with self-weathering steel treated to produce a rust-like
finish. The average distance between 138/69-kV towers will be 350 feet. Structure heights will
vary depending on terrain and the requirement to maintain minimum conductor clearances from
ground. The 138/69-kV double-circuit towers will vary in height from 55 to 100 feet.
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1.1.1.4 Alternative 500-kV Single Circuit Monopole Structures
The alternative 500-kV Monopole structures if use would be fabricated with self-weathering
tubular steel treated to produce a rust-like finish. The average distance between 500-kV
Monopoles would be 800 to 1,000 feet. Structure heights would vary depending on terrain and
the requirement to maintain minimum conductor clearances from ground. The 500-kV Monopole
structures would vary in height from 120 to 130 feet.
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28
Table 1-1 describes the number and type of structures by typical height, typical distances
between structures, and temporary and permanent disturbance areas by structure.
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30
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Table 1-1.
Appendix B
Proposed Structure Characteristics
Typical
Height
(feet)
No. of
Structures1/
Average
Distance
Between
Structures1
(feet)
500-kV Single Circuit
Lattice Structure
110-195
1,228
1,200-1,300
500-kV Single Circuit HFrame Structure
100-165
75
900-1,300
138/69-kV Double Circuit
Monopole Structure
55-100
72
350
Structure Type
1
Short Term
Disturbance
Area per
structure
(sq. feet.)
Long Term
Disturbance
Area per
structure
(sq. feet.)
ROW Width 250
feet x 250 feet =
1.43 acre
ROW Width 250
feet x 250 feet =
1.43 acre
ROW Width 100
feet x 100 feet =
0.23 acre
ROW Width 50
feet x 50 feet =
0.06 acre
ROW Width 50
feet x 50 feet =
0.06 acre
ROW Width 50
feet x 50 feet =
<0.01 acre
Reasonable estimate from preliminary engineering.
2
3
1.1.2 Structure and Conductor Clearances
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Conductor phase-to-phase and phase-to-ground clearance parameters are determined in
accordance with IPC Company Standards and the National Electrical Safety Code (NESC),
ANSI C2, produced by the American National Standards Institute (ANSI). These documents
provide minimum distances between the conductors and ground, crossing points of other lines
and the transmission support structure, and other conductors, and minimum working clearances
for personnel during energized operation and maintenance activities (IEEE 2007). Typically, the
clearance of conductors above ground is 37 feet for 500-kV, but where the line crosses land
used for agricultural purposes a minimum clearance of 40 feet will be used. For the 138/69-kV
double-circuit section, the 12.5-kV underbuild distribution conductor clearance is 22 feet above
grade. During detailed design, clearances may be increased to account for localized conditions.
14
1.1.3 Structure Foundations
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The 500-kV single-circuit lattice steel structures each require four foundations with one on each
of the four corners of the lattice towers. The foundation diameter and depth will be determined
during final design and are dependent on structure loading conditions and the type of soil or
rock present at each specific site. Typically, the foundations for the single-circuit tangent lattice
towers will be composed of steel-reinforced concrete drilled piers with a typical diameter of 4
feet and a depth of approximately 15 feet. For the 500-kV H-frame structures each structure will
require two foundations, one for each pole that comprises the H-frame structure. At angle and
dead-end structures the H-frames will be replaced with three poles each with its own foundation.
They will be steel-reinforced drilled piers with a typical diameter of 6 feet and a depth of
approximately 25 feet. The 138/69-kV monopole structures will be a combination of directembedded steel poles and self-supported poles on drilled pier foundations. Tangent structures
will be direct-embedded in a single drilled boring, typically 5 feet in diameter and 15 feet deep.
Angle and dead-end structures will be on steel-reinforced drilled pier foundations with a typical
diameter of 5 feet and a depth of approximately 20 feet.
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Typical foundation diameters and depths for the proposed structure families are shown in Table
1-2.
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Table 1-2.
Appendix B
Foundation Excavation Dimensions
Proposed Structures
Number of Holes Per
Structures Structure
500-kV Single Circuit - Light Tangent Lattice Tower
500-kV Single Circuit - Heavy Tangent Lattice Tower
500-kV Single Circuit - Small Angle Lattice Tower
500-kV Single Circuit - Medium Angle Lattice Tower
500-kV Single Circuit - Medium Dead-End Lattice
1
Tower
500-kV Single Circuit - Heavy Dead-End Lattice
Tower
500-kV Single Circuit – Tangent H-Frame Structure
500-kV Single Circuit – Angle H-Frame Structure
500-kV Single Circuit – Dead-end H-Frame Structure
138/69-kV Double Circuit - Monopole Tangent
Structure
138/69-kV Double Circuit - Monopole Angle Structure
138/69-kV Double Circuit - Monopole Dead-end
Structure
2
1
3
1.2 Conductors
Depth
(feet)
Diameter
(feet)
Concrete
(cubic
yards)
964
82
12
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103
4
4
4
4
4
15
18
16
21
28
4
5
6
6.5
7
28
52
68
104
160
40
4
30
7
172
61
8
6
37
2
3
3
1
25
30
40
15
6
7
8
5
53
129
224
N/A
5
30
1
1
20
25
5
6
15
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“Dead-end structure” typically refers to a structure that is placed at a point where the transmission line turns direction.
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The proposed conductor for the 500-kV lattice structure lines is 1,272 KCM2 45/7 ACSR “Bittern”
45/73. Each phase of a 500-kV three-phase circuit4 will be composed of three subconductors in
a triple bundle configuration. The individual 1,272 KCM conductors will be bundled in a
triangular configuration with spacing of 25 inches between horizontal subconductors and 18
inches of diagonal separation between the top two conductors and the lower conductor (see
Figure 1-1). The triple-bundled configuration is proposed to provide adequate current carrying
capacity and to provide for a reduction in audible noise and radio interference as compared to a
single large-diameter conductor. Each 500-kV subconductor will have a 45/7 aluminum/steel
stranding, with an overall conductor diameter of 1.345 inches and a weight of 1.432 pounds per
foot and a non-specular finish5.
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The proposed conductor for the 138/69-kV monopole structure lines is 397 KCM 26/7 ACSR
“Ibis” (138KV, one conductor per phase), 4/0 6/1 ACSR “Penguin” (69 KV, one conductor per
phase), No. 4 Copper Conductor (12.5-kV Distribution, one conductor per phase plus neutral
wire), and a 3/8” EHS 7-strand shield wire. Conductors will be aligned with typical vertical
spacing of 8 feet between shield wire and 69 or 138 KV phase wires, 6 feet between phase
wires, and a minimum of 12 feet between 138 or 69 KV phase wires and distribution wires.
20
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Where multiple conductors are utilized in a bundle for each phase, the bundle spacing will be
maintained through the use of conductor spacers at intermediate points along the conductor
bundle between each structure. The spacers serve a dual purpose: in addition to maintaining
2
KCM (1,000 cmils) is a quantity of measure for the size of a conductor; kcmil wire size is the equivalent cross-sectional area in
thousands of circular mils. A circular mil (cmil) is the area of a circle with a diameter of one thousandth (0.001) of an inch.
3
Aluminum/steel refers to the conductor material composition. The preceding numbers indicate the number of strands of each
material type present in the conductor (i.e., 45/7 aluminum/steel stranding has 45 aluminum strands wound around 7 steel
strands).
4
For AC transmission lines, a circuit consists of three phases. A phase may consist of one conductor or multiple conductors (i.e.,
subconductors) bundled together.
5
Non-specular finish refers to a “dull” finish rather than a “shiny” finish.
November 2011
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Appendix B
1
2
3
the correct bundle configuration and spacing, the spacers are also designed to damp out windinduced vibration in the conductors. The number of spacers required in each span between
towers will be determined during the final design of the transmission line.
4
1.3 Other Hardware
5
1.3.1 Insulators
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As shown in Figure 1-1 and Figure 1-2, the typical insulator assemblies for 500-kV steel lattice
tangent structures and H-frame structures will consist of two insulators hung in the form of a “V.”
As shown in Figure 1-3, insulator assemblies for 138/69-kV tangent structures will consist of
supported insulators which extend horizontally away from the monopole. Insulators are used to
suspend each conductor bundle (phase) from the structure, maintaining the appropriate
electrical clearance between the conductors, the ground, and the structure. The V-shaped
configuration of the 500-kV insulators also restrains the conductor so that it will not swing into
the structure in high winds. Dead-end insulator assemblies for the transmission lines will use an
I-shaped configuration, which consists of insulators hung from either a tower dead-end arm or a
dead-end pole in the form of an “I.” Insulators will be composed of grey porcelain or green-tinted
toughened glass.
17
1.3.2 Grounding Systems
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Alternating current (AC) transmission lines such as the Project transmission lines have the
potential to induce currents on adjacent metallic structures such as transmission lines, railroads,
pipelines, fences, or structures that are parallel to, cross, or are adjacent to the transmission
line. Induced currents on these facilities will occur to some degree during steady-state operating
conditions and during a fault condition on the transmission line. For example, during a lightning
strike on the line, the insulators may flash over, causing a fault condition on the line and current
will flow down the structure through the grounding system (i.e., ground rod or counterpoise) and
into the ground. The magnitude of the effects of the AC induced currents on adjacent facilities is
highly dependent on the magnitude of the current flows in the transmission line, the proximity of
the adjacent facility to the line, and the distance (length) for which the two facilities parallel one
another in proximity.
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The methods and equipment needed to mitigate these conditions will be determined through
electrical studies of the specific situation. As standard practice and as part of the design of the
Project, electrical equipment and fencing at the substation will be grounded. All fences, metal
gates, pipelines, metal buildings, and other metal structures adjacent to the ROW that cross or
are within the transmission line ROW will be grounded as determined necessary. If applicable,
grounding of metallic objects outside of the ROW may also occur, depending on the distance
from the transmission line as determined through the electrical studies. These actions take care
of the majority of induced current effects on metallic facilities adjacent to the line by shunting the
induced currents to ground through ground rods, ground mats, and other grounding systems,
thus reducing the effect that a person may experience when touching a metallic object near the
line (i.e., reduce electric shock potential). In the case of a longer parallel facility, such as a
pipeline parallel to the Project over many miles, additional electrical studies will be undertaken
to identify any additional mitigation measures (more than the standard grounding practices) that
will need to be implemented to prevent damaging currents from flowing onto the parallel facility,
and to prevent electrical shock to a person that may come in contact with the parallel facility.
Some of the typical measures that could be considered for implementation, depending on the
degree of mitigation needed, could include:
46
47
x
Fault Shields – shallow grounding conductors connected to the affected structure
adjacent to overhead electrical transmission towers, poles, substations, etc. They are
November 2011
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Transmission Line and Substation Components
Appendix B
intended to provide localized protection to the structure and pipeline coating during a
fault event from a nearby electric transmission power system.
1
2
3
4
5
x
Lumped Grounding – localized conductor or conductors connected to the affected
structure at strategic locations (e.g., at discontinuities). They are intended to protect
the structure from both steady-state and fault AC conditions.
6
7
8
9
10
x
Gradient Control Wires – a continuous and long grounding conductor or conductors
installed horizontally and parallel to a structure (e.g., pipeline section) at strategic
lengths and connected at regular intervals. These are intended to provide protection
to the structure and pipeline coating during steady-state and fault AC conditions from
nearby electric transmission power systems.
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25
x
Gradient Control Mats – typically used for aboveground components of a pipeline
system, these are buried ground mats bonded to the structure, and are used to
reduce electrical step and touch voltages in areas where people may come in
contact with a structure subject to hazardous potentials. Permanent mats bonded to
the structure may be used at valves, metallic vents, cathodic protection test stations,
and other aboveground metallic and nonmetallic appurtenances where electrical
contact with the affected structure is possible. In these cases there is no “standard”
solution that will solve these issues every time. Instead, each case must be studied
to determine the magnitude of the induced currents and the most appropriate
mitigation given the ground resistivity, distance paralleled, steady-state and fault
currents, fault clearing times expected on the transmission line, and distance
between the line and the pipeline, to name a few of the parameters. If the electrical
studies indicate a need to install cathodic protection devices on a parallel pipeline
facility, a distribution supply line interconnection may be needed to provide power to
the cathodic protection equipment.6
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27
28
During final design of the transmission line, appropriate electrical studies will be conducted to
identify the issues associated with paralleling other facilities and the types of equipment that will
need to be installed (if any) to mitigate the effects of the induced currents.
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1.3.3 Minor Additional Hardware
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32
33
In addition to the conductors, insulators, and overhead shield wires, other associated hardware
will be installed on the tower as part of the insulator assembly to support the conductors and
shield wires. This hardware will include clamps, shackles, links, plates, and various other pieces
composed of galvanized steel and aluminum.
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A grounding system will be installed at the base of each transmission structure that will consist
of copper or galvanized ground rods embedded into the ground in immediate proximity to the
structure foundation and connected to the structure by a buried copper lead. When the
resistance to ground for a grounded transmission structure is greater than a specified
impedance value with the use of ground rods, counterpoise will be installed to lower the
resistance to below a specified impedance value. Counterpoise consists of a bare copper-clad
or galvanized-steel cable buried a minimum of 12 inches deep, extending from structures (from
one or more legs of structure) for approximately 200 feet within the ROW.
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43
44
Other hardware that is not associated with the transmission of electricity may be installed as
part of the Project. This hardware may include aerial marker spheres or aircraft warning lighting
as required for the conductors or structures per Federal Aviation Administration (FAA)
6
NACE International. 2003. Grounding Systems. Houston, TX. Available online at
http://www.nace.org/content.cfm?parentid=1001&currentID=1001
November 2011
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Transmission Line and Substation Components
Appendix B
1
2
3
4
regulations.7 Structure proximity to airports and structure height are the determinants of whether
FAA regulations will apply based on an assessment of wire/tower strike risk. IPC does not
anticipate that structure lighting will be required because proposed structures will be less than
200 feet tall and will not be near airports that require structure lighting.
5
1.4 Communication Systems
6
1.4.1 Optical Ground Wire
7
8
9
10
11
12
13
Reliable and secure communications for system control and monitoring is very important to
maintain the operational integrity of the Project and of the overall interconnected system.
Primary communications for relaying and control will be provided via the optical ground wire
(OPGW) that will be installed on the transmission lines; this path is solely for IPC use and will
not be used for commercial purposes. A secondary communication path may also be developed
using a power line carrier. No new microwave sites are anticipated for the Project. Updated
microwave equipment may be installed at the substations.
14
15
16
17
18
19
20
21
Each structure will have two lightning protection shield wires installed on the structure peaks
(see Figure 1-1 and Figure 1-2). One of the shield wires will be composed of extra high strength
steel wire with a diameter of 0. 495 inch and a weight of 0.517 pound per foot. The second
shield wire will be an OPGW constructed of aluminum and steel, which carries 48 glass fibers
within its core. The OPGW will have a diameter of 0.646 inch and a weight of 0.407 pound per
foot. The glass fibers inside the OPGW shield wire will provide optical data transfer capability
among IPC’s facilities along the fiber path. The data transferred are required for system control
and monitoring.
22
1.4.2 Communications Sites
23
24
25
26
27
As the data signal is passed through the optical fiber cable, the signal degrades with distance.
Consequently, signal communications sites are required to amplify the signals if the distance
between substations or communications sites exceeds approximately 40 miles. As summarized
in Table 1-3, a total of eight communications sites will be required. Communication sites will be
located on private and public lands.
28
Table 1-3.
County
Morrow
Umatilla
Union
Baker
Malheur
Owyhee
29
30
31
32
33
34
Proposed Communications Site Locations
Number
1
1
1
2
3
0
Total Construction
Acres
0.2
0.2
0.2
0.5
0.7
0
Total Operations
Acres
0.1
0.1
0.1
0.3
0.4
0
Ownership
Private
Private
BLM
Private, BLM
2 BLM, 1 Private
--
The typical site will be 100 feet by 100 feet, with a fenced area of 75 feet by 75 feet. A
prefabricated concrete communications shelter with dimensions of approximately 11.5-foot by
32-foot by 12-foot-tall will be placed on the site and access roads to the site and power from the
local electric distribution circuits will be required. An emergency generator with a liquid
petroleum gas fuel tank will be installed at the site inside the fenced area. Two diverse cable
7
U.S. Department of Transportation, Federal Aviation Administration, Advisory Circular AC 70/7460-1K Obstruction
Marking and Lighting, August 1, 2000; and Advisory Circular AC 70/7460-2K Proposed Construction or Alteration of
Objects that May Affect the Navigable Airspace, March 1, 2000.
November 2011
12
Transmission Line and Substation Components
Appendix B
1
2
routes (aerial and/or buried) from the transmission ROW to the equipment shelter will be
required. Figure 1-7 illustrates the plan arrangement of a typical communications sites.
3
4
Figure 1-7.
5
1.5 Access Roads
Typical Communication Site
6
7
8
9
10
The Project will require vehicular access to each structure for the life of the Project. For the
purposes of calculating ground disturbance and operational needs, the Project has classified
access roads into five categories—four of them permanent roads and one of them temporary.
Table 1-4 summarizes the five categories of roads needed for accessing the transmission line
structures for the Project.
11
12
13
14
15
16
17
18
19
The largest of the heavy equipment needed, which dictates the minimum needed road
dimensions, is a truck-mounted aerial lift crane with 100,000 pounds gross vehicle weight, 8-by8 drive, and a 210-foot telescoped boom. To accommodate this equipment, the road
specifications require a 14-foot-wide travel surface and 16- to 20-foot-wide travel surface for
horizontal curves (Figure 1-8). The required travel way in areas of rolling to hilly terrain will
require a wider disturbance to account for cuts and fills. In addition, IPC plans to conduct
maintenance using live-line maintenance techniques, thereby avoiding an outage to the critical
transmission line infrastructure. High-reach bucket trucks along with other equipment will be
used to conduct these activities.
20
November 2011
13
Transmission Line and Substation Components
1
Table 1-4.
Road
Category
Existing roads
requiring no
improvement
Existing roads
requiring
improvement
New roads
- Bladed
- Overland
Travel
- Overland
Travel with
Clearing
ATV Trails
ATV access to
helicopter sites
Temporary
roads
Access to
laydown and fly
yards
Access for
construction,
pulling and
tension
November 2011
Appendix B
Access Road Requirements for Transmission Line System
Construction Use
Routine Operations Use
Non-Routine
Operations
Use
No change
No change
No change
Surfaced and unsurfaced 14foot-wide straight sections of
road and 16- to 20-foot-wide
sections at corners. Heavy
machinery used as needed to
ensure safe operation and
access of vehicles.
For routine activities, an 8-foot portion of the
authorized road will be used and vehicles will
drive over the vegetation and brush where safe
and practicable. Vegetation that may interfere
with the safe operation of vehicles will be
removed as necessary.
New surfaced and un-surfaced,
14-foot-wide straight sections of
road and 16- to 20-foot-wide
sections at corners.
Bladed Roads may be
constructed to access structures
in steep or uneven terrain. Used
on sideslopes greater than 8%.
For routine activities, an 8-foot portion of the
road will be used and vehicles will drive over
the vegetation where safe and practicable.
Vegetation that may interfere with the safe
operation of vehicles will be removed as
necessary.
Overland Travel Routes created
by direct vehicle travel over low
growth vegetation ; or with
minor clearing and grading
using heavy machinery to
remove larger vegetation or
other obstructions as needed to
ensure safe operation and
access of vehicles.
Unsurfaced 8-foot-wide straight
sections of road and 8- to 10foot-wide sections at corners.
14-foot-wide straight sections of
road and 16- to 20-foot-wide
sections at corners.
For nonroutine
maintenance
requiring
access by
larger vehicles
the full width of
the access
road may be
used. Access
roads will be
maintained, as
necessary, but
will not be
routinely
graded.
For routine activities, an 8-foot portion of the
road will be used and vehicles will drive over
the vegetation where safe and practicable.
Vegetation that may interfere with the safe
operation of vehicles will be removed as
necessary.
None
None—contours will be restored, and the road
will be ripped and seeded.
None
14
Transmission Line and Substation Components
Appendix B
1
2
Figure 1-8.
November 2011
Typical Road Sections for Different Terrains
15
Transmission Line and Substation Components
Appendix B
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Waterbody Crossings with Access Roads: Access roads will be constructed to minimize
disruption of natural drainage patterns including perennial, intermittent and ephemeral streams.
In order to estimate the impact on stream crossings, an assessment of stream crossing types
was made based on preliminary engineering plans. These are conservative estimates using
consistent quantitative descriptions for each crossing method. As the engineering plans are
advanced for new access roads, site specific crossings will be designed and crossing
disturbance will vary. On all federally managed lands, IPC will consult with the managing
agency regarding relevant standards and guidelines pertaining to road crossing methods at
waterbodies. Consultation will include site assessment, design, installation, maintenance, and
decommissioning. New crossings of canals, ditches and perennial streams will be avoided to
the extent practical by using existing crossings, but some new crossings are expected. The
performance of stream crossings will be monitored for the life of the access road, and
maintained or repaired as necessary to protect water quality. Four types of waterbody crossings
are considered as part of the Project (Figure 1-9 through Figure 1-11). They are:
15
16
17
Type 1 – Drive through with or without minor grading and/or minimal fill to match existing
stream profile: Crossing of a seasonally dry channel with minimal grading and/or fill to
repair surface ruts or re-contour minor surface erosion (Figure 1-9).
18
19
20
21
22
23
24
25
26
27
Figure 1-9. Type 1 Drive Through Stream Crossing Methods
Type 2 – Drive through/ Ford: Crossing of a channel that includes grading and
stabilization. Stream banks and approaches would be graded to allow vehicle passage
and stabilized with rock, geotextile fabric or other erosion control devices. The stream
bed would in some areas be reinforced with coarse rock material, where approved by
the land-management agency, to support vehicle loads, prevent erosion and minimize
sedimentation into the waterway. The rock would be installed in the stream bed such
that it would not raise the level of the streambed, thus allowing continued movement of
water, fish and debris. Fords may be constructed in small, shallow streams (less than 2’
November 2011
16
Transmission Line and Substation Components
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
Appendix B
stream depth and 20’ active stream width) and rocky substrates. Fords may also be
appropriate on wider streams when they have a poorly defined channel that often
changes course from excessive bedload. A ford crossing results in an average
disturbance profile of 25 feet wide (along the water body) and 50 feet long (along the
roadway) for 1,000 square feet or 0.02 acre at each crossing. Disturbance amount is
estimated based on need to get equipment into the riparian area to build the 14-footwide travel way and protect it from erosion by adding armoring. Flowing streams may
warrant temporary structures to maintain fish passage, hydrology and water quality to
span active the channel during construction activities (Figure 1-10).
Type 3 – Culvert: Crossing of a stream or seasonal drainage that includes installation
of a culvert and a stable road surface established over the culvert for vehicle passage.
Culverts would be designed and installed under the guidance of a qualified engineer
who, in collaboration with a hydrologist and aquatic biologist where required by the land
management agency, would recommend placement locations; culvert gradient, height,
and sizing; and proper construction methods. Culvert design would consider bedload
and debris size and volume. The disturbance footprint for culvert installation is estimated
to be 50 feet wide (along the waterbody) and 150 feet long (along the road) for 7,500
square feet or 0.17 acre at each crossing. Ground-disturbing activities would comply with
Agency-approved BMPs. Construction would occur during periods of low flow. The use
of equipment in streams would be minimized. All culverts would be designed and
installed to meet desired riparian conditions, as identified in applicable unit management
plans. Culvert slope would not exceed stream gradient. Typically, culverts would be
partially buried in the streambed to maintain streambed material in the culvert. Sandbags
or other non-erosive material would be placed around the culverts to prevent scour or
water flow around the culvert. Adjacent sediment control structures such as silt fences,
check dams, rock armoring, or riprap may be necessary to prevent erosion or
sedimentation. Stream banks and approaches may be stabilized with rock or other
erosion control devices (Figure 1-10).
29
November 2011
17
Transmission Line and Substation Components
Appendix B
1
2
TYPE 3 CULVERT
3
4
5
6
7
8
9
10
11
12
Figure 1-10. Type 2 and Type 3 Crossing Methods
Type 4 – Channel spanning structures including fish passage: Crossing of a water
body identifies as containing a sensitive fish species that includes installation of a large
diameter culvert, arch culvert or short span bridge and a stable road surface established
over the structure for vehicle passage. Channel spanning structures would be designed
and installed under the guidance of a qualified engineer who, in collaboration with a
hydrologist and aquatic biologist would recommend placement locations; structure
gradient, height, and sizing; and proper construction methods. The disturbance footprint
for channel spanning structure installation is estimated to be 60 feet wide (along the
November 2011
18
Transmission Line and Substation Components
1
2
3
4
5
Appendix B
water body) and 150 feet long (along the road) for 9,000 square feet or 0.2 acre at each
crossing. (Figure 1-11).
Figure 1-11.
November 2011
Type 4 – Channel Spanning Structures Including Fish Passage
19
Transmission Line and Substation Components
Appendix B
1
2
3
4
Wetlands Crossings with Access Roads: During construction and for routine and emergency
operations, access across wetlands to individual structure locations may be necessary.
Selection of final wetland crossing techniques will be based on final access road alignment and
wetland characteristics:
5
6
7
8
1. Constructing at grade roads with geotextiles and road materials which allow for water
through-flow. This type of road will be below water during certain times of the year which
will make locating the roads difficult, and the depth of the water over the drivable surface
may make travel over the submerged road surface impractical or not feasible.
9
10
11
12
13
14
15
16
17
18
19
2. Limiting structure access across wetlands to dry or frozen conditions along with the use
of low ground pressure tires or specialized tracked vehicles. This approach does not
allow sufficient flexibility for emergency restoration and for operation and maintenance
as the depth of water and/or soil conditions will not allow access to the structures during
certain times of the year. Construction of ice roads in wetlands involves using lightweight
equipment such as snowmobiles to tamp down existing snow cover and vegetation to
allow penetration of frost into the wetland soils. This operation is followed by packing
with heavier tracked equipment such as Bombardiers or wide tracked dozers. There is a
relatively small window of time during the year where cold enough weather is present to
allow for this technique thereby restricting the flexibility required for operation and
maintenance in other seasons besides winter.
20
21
22
23
24
25
26
3. Installing temporary matting materials to allow access for heavy vehicles and equipment.
The mats typically come in the form of heavy timbers bolted together or interlocking
pierced-steel planks. Mats spread the concentrated axle loads from equipment over a
much larger surface area thereby reducing the bearing pressure on fragile soils.
However, mats are less effective when standing water is present. Matting has a limited
service life before replacement is required and must be stored for maintenance and
emergency restoration activities.
27
28
29
30
31
32
33
34
35
36
4. Constructing raised fill embankments for permanent above-grade access roads in
wetlands such that the travel surface is higher in elevation than the ordinary high water
level. The construction of above-grade access roads allows for the use of the types of
equipment described above and the most flexibility for construction. All waterbody and
wetland disturbances will be completed under the terms of a U.S. Army Corps of
Engineers Clean Water Act Section 404 permit, the National Pollutant Discharge
Elimination System Construction Stormwater Permit (Clean Water Act 402), and State
401 water quality certification requirements that govern activities within any waters of the
United States. In Idaho, there is an additional requirement for a stream channel
alteration permit.
37
38
39
40
41
5. Construction using helicopters in wetlands. Transmission tower structures proposed for
the Project could be erected by helicopter, if needed. However, in each case, the use of
ground based vehicles will still be required and will not eliminate the need for an access
road to each structure to complete construction or during inspections and live-line
maintenance activities.
November 2011
20
Transmission Line and Substation Components
Appendix B
1
1.6 Substations
2
3
The Project includes expansion at one planned (Grassland) and one existing (Hemingway)
substation.
4
1.6.1 Substation Components
5
The following sections describe key components of substations.
6
7
8
9
10
11
12
1.6.1.1 Bay
A substation “bay” is the physical location within a substation fenced area where the highvoltage circuit breakers and associated steel transmission line termination structures, highvoltage switches, bus supports, controls, and other equipment are installed. For each
transmission line, 500-kV circuit breakers, high-voltage switches, bus supports, and
transmission line termination structures would typically be installed. The 500-kV transmission
line termination structures are approximately 125 to 135 feet tall.
13
14
15
16
17
The tallest structures in the substations will be the 500-kV dead-end structures, from 125 to 135
feet tall, and/or a microwave antenna tower, which will be in the range of 100 feet or more,
depending on the height needed to maintain line of sight to the nearest microwave relay site.
Figure 1-12 is a perspective sketch illustrating the appearance of a typical 500-kV substation
with multiple line connections.
18
1.6.1.2 Access Road
Permanent all-weather access roads are required at substation sites to provide access for
personnel, material deliveries, vehicles, trucks, heavy equipment, low-boy tractor trailer rigs
(used for moving large transformers), and ongoing maintenance activities at each site.
Substation access roads are normally well-compacted, graded gravel roads approximately
20 feet in width with a minimum 110-foot turning radius to accommodate the delivery of large
transformers to the site. No new access roads are necessary for access to the Grassland and
Hemingway substation locations.
19
20
21
22
23
24
25
November 2011
21
Transmission Line and Substation Components
1
2
3
4
5
6
7
8
9
Figure 1-12.
Appendix B
Typical 500-kV Substation
1.6.1.3 Control Building
One or more control buildings are required at each substation to house protective relays, control
devices, battery banks for primary control power, and remote monitoring equipment. The size
and construction of the building depends on individual substation requirements. Typically, the
control building will be constructed of concrete block, pre-engineered metal sheathed, or
composite surfaced materials. Special control buildings may be developed within the substation
developments to house other control and protection equipment.
11
12
13
14
15
16
1.6.1.4 Fencing and Landscaping
Security fencing will be installed around the entire perimeter of each new or expanded
substation to protect sensitive equipment and prevent accidental contact with energized
conductors by third parties. This 7-foot-high fence will be constructed of chain link with steel
posts, with one foot of barbed wire above the chain link, and with locked gates. If required by
the landowner or permitting agency, landscaping will be established using drought-resistant
vegetation where allowed. The Hemingway Substation is already fenced.
17
1.6.2 Distribution Supply Lines
18
19
20
21
22
23
Station service power will be required at each substation or communication sites. Typically,
station service power is provided from a local electric distribution line, located in proximity to the
substation or communication site. The voltage of the distribution supply line is typically 34.5-kV
or lower and carried on wood poles. For the Grassland Substation, it will be necessary to extend
the electric distribution line from a suitable take-off point on the existing distribution line to the
new substation site. The location and routing of the existing distribution lines to the new
10
November 2011
22
Transmission Line and Substation Components
Appendix B
1
2
3
4
5
6
substation will be determined during the final design process. The distance from Grassland
Substation to the nearest existing distribution supply is approximately 4,000 feet. The
Hemingway Substation exists and new distribution line extensions to provide station service
power will not be required. However, modifications to the existing distribution facilities may be
necessary to provide increased capacity to support the expansions at the existing Hemingway
Substation.
7
2.0
8
9
The following section and subsections detail construction activities for the Project, including
transmission line, substation communication, and associated ancillary features.
SYSTEM CONSTRUCTION
10
2.1 Land Requirements and Disturbance
11
2.1.1 Right-of-Way Width
12
13
14
15
IPC proposes to acquire a permanent 250-foot-wide ROW for the 500-kV single-circuit sections
of the Project and a 100-foot-wide ROW for the 138/69-kV portions of the Project. Figure 1-4
illustrates the ROW width requirements for the proposed structures. The determination of these
widths is based on two criteria:
16
17
x
Sufficient clearance must be maintained during a high wind event when the
conductors are blown towards the ROW edge.
18
19
20
x
Sufficient room must be provided within the ROW to perform transmission line
maintenance. See Section 3.1 of this appendix for details of maintenance
requirements.
21
22
23
24
25
26
27
28
Table 2-1 provides a breakdown of the amount of land needed temporarily for construction and
for operation over the life of the Project. During construction, temporary permission will be
required from landowners and land management agencies during construction for off-ROW
access, staging areas, helicopter fly yards, and material storage. During operation, Project land
requirements will be restricted to the ROW, substations, and communication facilities. Access to
the ROW will be in accordance with the land rights obtained as part of the easement acquisition
process. As further details of the final Project design are engineered, the amount of land
required may change.
29
Table 2-1.
Summary of Land Required for Construction and Operations
Division by County
Morrow County
T-Line ROW
Off-ROW Staging Area
Off-ROW Fly Yards
Off ROW Wire Pulling/Splicing Sites
Off-ROW Access Roads
OPGW Communication Sites (1)
Grassland Substation
County Total Segment Subtotal
Land Required for
Construction (acres)
Land Required for Operations
(acres)
1,388.4
39.9
15.3
104.8
18.6
0.2
30.0
1,597.2
1,388.4
0
0
0
9.3
0.1
6.0
1,403.8
30
November 2011
23
Transmission Line and Substation Components
1
Table 2-1.
Appendix B
Summary of Land Required for Construction and Operations (continued)
Division by County
Umatilla County
T-Line ROW
Off-ROW Staging Area
Off-ROW Fly Yards
Off ROW Wire Pulling/Splicing Sites
Off-ROW Access Roads
OPGW Communication Sites (1)
County Total Segment Subtotal
Union County
T-Line ROW
Off-ROW Staging Area
Off-ROW Fly Yards
Off ROW Wire Pulling/Splicing Sites
Off-ROW Access Roads
OPGW Communication Sites (1)
County Total Segment Subtotal
Baker County
T-Line ROW
Off-ROW Staging Area
Off-ROW Fly Yards
Off ROW Wire Pulling/Splicing Sites
Off-ROW Access Roads
OPGW Communication Sites (2)
County Total Segment Subtotal
Malheur County
T-Line ROW
Off-ROW Staging Area
Off-ROW Fly Yards
Off ROW Wire Pulling/Splicing Sites
Off-ROW Access Roads
OPGW Communication Sites (3)
County Total Segment Subtotal
Owyhee County
T-Line ROW
Off-ROW Staging Area
Off-ROW Fly Yards
Off ROW Wire Pulling/Splicing Sites
Off-ROW Access Roads
Hemingway Substation
County Total Segment Subtotal
Land Required for
Construction (acres)
Land Required for Operations
(acres)
1,498.2
41.2
44.5
140.5
71.8
0.2
1,796.4
1,498.2
0
0
0
35.9
0.1
1,534.2
1,195.2
41.1
103.8
38.2
72.0
0.2
1,450.5
1,195.2
0
0
0
36.0
0.1
1,231.3
2,157.7
43.8
116.1
112.3
161.5
0.5
2,591.9
2,157.7
0
0
0
80.8
0.3
2,238.8
2,184.3
63.9
134.0
120.2
163.0
0.7
2,666.1
2,184.3
0
0
0
81.5
0.4
2,266.2
720.9
42.5
59.8
41.9
55.6
4.0
924.7
720.9
0
0
0
27.8
2.0
750.7
2
November 2011
24
Transmission Line and Substation Components
1
Table 2-1.
Appendix B
Summary of Land Required for Construction and Operations (continued)
Division by County
Total Project
Transmission line ROW
Off-ROW Staging Area
Off-ROW Fly Yards
Off ROW Wire Pulling/Splicing Sites
Off-ROW Access Roads
OPGW Communication Site(s)
Substations
Total Project
Land Required for
Construction (acres)
Land Required for Operations
(acres)
9,145.1
272.4
473.5
557.9
542.5
1.8
34.0
11,027.2
9,145.1
0
0
0
271.3
1.0
8.0
9,425.4
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
Assumptions/Notes:
1. The exact land requirements would depend on the final detailed design of the transmission line, which is influenced by the
terrain, land use, and economics. Alignment options may also slightly increase or decrease these values.
2. ROW width for 500-kV single circuit is 250 feet.
3. ROW width for 138/69-kV double-circuit is 100 feet.
4. The dimensions of the tower construction pads and area permanently occupied by towers after restoration are based on the
dimensions specified in Figure 1-1.
5. The staging areas would serve as field offices, reporting locations for workers, parking space for vehicles and equipment,
sites for material storage, fabrication assembly, equipment maintenance, and concrete batch plants. Staging/material storage
yards/batch plants would be approximately 20 acres for 500-kV lines. They would be located every 20 to 30 miles along the
line.
6. Fly yards would be 10 to 15 acres located every 5 to 10 miles. Values in table assume helicopter construction throughout all
single-circuit 500-kV lines. The construction contractor may choose to construct using ground-based techniques, therefore,
not utilizing fly yards.
7. Typical wiring pulling/splicing sites would be the ROW width x 600 to 900 feet located every 2 to 3 miles. Typically, the only
sites that would be off of the ROW would be at large-angle dead-ends. It is estimated that one in four sites would be off of the
ROW.
8.
Miles of access road are based on an indicative layout of access roads along the current preferred route as of the date of this
document.
22
2.1.2 Right-of-Way Acquisition
23
24
25
All portions of the route must obtain new ROWs through a combination of ROW grants and
easements between IPC and various federal, state, and local governments; other companies
(e.g., utilities and railroads), and private landowners.
26
27
28
29
30
Close coordination with all property owners and land agencies during initial surveys and the
construction phase of the Project is essential for successful completion of the Project. In the
early stages of the Project, landowners will be contacted to obtain right-of-entry for surveys and
for geotechnical drilling at selected locations. Each landowner along the final centerline route
will be contacted to explain the Project and to secure right-of-entry and access to the ROW.
31
32
33
34
35
36
All negotiations with landowners will be conducted in good faith, and the Project’s effect on the
parcel or any other concerns the landowner may have will be addressed. ROWs for
transmission line facilities on private lands will be obtained as perpetual easements. Land for
substation or communication sites will be obtained in fee simple where located on private land.
Every effort will be made to purchase the land and/or obtain easements on private lands
through reasonable negotiations with the landowners.
37
38
39
40
41
42
Section 2.2.4 of the POD describes North American Electricity Reliability Corporation (NERC)
and Western Electricity Coordinating Council (WECC) reliability standards and capacity needs
for the Project. To achieve the capacity needed to serve present and future loads within IPC’s
service areas, the WECC requires a minimum separation from existing transmission lines that
serve substantially the same load as that served by the new Boardman to Hemingway
transmission project. In these cases, the Project transmission lines must be located at least
November 2011
25
Transmission Line and Substation Components
Appendix B
1
2
3
4
5
1,500 feet as a general rule from the nearest existing 230 kV or higher-voltage transmission
lines or the length of the longest span where the two lines are adjacent to each other. Land
between ROWs that are separated to meet reliability criteria will not be encumbered with an
easement but could practically be limited in land uses due to the proximity of two or more large
transmission lines.
6
2.1.3 Land Disturbance
7
8
9
10
Land disturbance as described in Table 2-2 is the estimated amount of land that will be
disturbed during construction or required to be permanently converted to operational uses. The
areas are reported by county. These uses are less than the amount of land for which
operational controls are required over the life of the Project as described in Table 2-1.
11
12
Table 2-2.
Summary of Land Disturbed during Construction and Used during
Permanent Operations
Segment/Project Component
Morrow County
Single Circuit 500-kV Pad
On ROW Pulling/Tensioning Sites
ON ROW Construction Roads
Off ROW Pulling/Tensioning Sites
Off ROW Access Roads
Staging Yards
Fly Yards
Communications Station (1)
Grassland Substation
County Total Segment Subtotal
Umatilla County
Single Circuit 500-kV Pad
On ROW Pulling/Tensioning Sites
ON ROW Construction Roads
Off ROW Pulling/Tensioning Sites
Off ROW Access Roads
Staging Yards
Fly Yards
Communications Station (1)
County Total Segment Subtotal
Land Affected During
Construction (acres)
Land Affected During Operations
(acres)
304.0
159.3
59.4
104.8
18.6
39.9
15.3
0.2
30.0
731.5
12.2
0
29.6
0
9.3
0
0
0.1
6.0
57.2
294.7
191.3
53.8
140.5
71.8
41.2
44.5
0.2
838.0
11.9
0
26.9
0
35.9
0
0
0.1
74.8
13
November 2011
26
Transmission Line and Substation Components
1
2
Table 2-2.
Appendix B
Summary of Land Disturbed during Construction and Used during
Permanent Operations (continued)
Segment/Project Component
Union County
Single Circuit 500 kV Pad
On ROW Pulling/Tensioning Sites
ON ROW Construction Roads
Off ROW Pulling/Tensioning Sites
Off ROW Access Roads
Staging Yards
Fly Yards
Communications Stations (1)
County Total Segment Subtotal
Baker County
Single Circuit 500 kV Pad
Double Circuit 138/69-kV Pad
On ROW Pulling/Tensioning Sites
ON ROW Construction Roads
Off ROW Pulling/Tensioning Sites
Off ROW Access Roads
Staging Yards
Fly Yards
Communications Station (2)
County Total Segment Subtotal
Malheur County
Single Circuit 500 KV Pad
On ROW Pulling/Tensioning Sites
ON ROW Construction Roads
Off ROW Pulling/Tensioning Sites
Off ROW Access Roads
Staging Yards
Fly Yards
Communications Station (3)
County Total Segment Subtotal
Owyhee County
Single Circuit 500 KV Pad
On ROW Pulling/Tensioning Sites
ON ROW Construction Roads
Off ROW Pulling/Tensioning Sites
Off ROW Access Roads
Staging Yards
Fly Yards
Communications Station
Hemingway Substation
County Total Segment Subtotal
Land Affected During
Construction (acres)
248.1
213.1
42.7
38.2
72.0
41.1
103.8
0.2
759.2
10.0
0
21.3
0
36.0
0
0
0.1
67.4
418.9
16.5
342.1
78.2
112.3
161.5
43.8
116.1
0.5
1,289.9
16.8
4.1
0
39.1
0
80.8
0
0
0.3
141.1
456.7
263.1
80.1
120.2
163.0
63.9
134.0
0.7
1,281.7
18.4
0
40.0
0
81.5
0
0
0.4
140.3
147.7
121.1
20.5
41.9
55.6
42.5
59.8
0
4.0
493.1
5.9
0
10.2
0
27.8
0
0
0
2.0
45.9
3
November 2011
Land Affected During Operation
(acres)
27
Transmission Line and Substation Components
1
2
Table 2-2.
Appendix B
Summary of Land Disturbed during Construction and Used during
Permanent Operations (continued)
Segment/Project Component
Total Project
Single Circuit 500 KV Pad
Double Circuit 138/69-kV Pad
On ROW Pulling/Tensioning Sites
ON ROW Construction Roads
Off ROW Pulling/Tensioning Sites
Off ROW Access Roads
Staging Yards
Fly Yards
Communications Station
Substations
Total Project
Land Affected During
Construction (acres)
1,870.2
16.5
1,290.0
334.7
557.9
542.5
272.4
473.5
1.8
34.0
5,393.5
Land Affected During Operations
(acres)
75.2
4.1
0
167.1
0
271.3
0
0
1.0
8.0
526.7
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
1
19
20
21
22
23
24
25
26
27
Estimates for construction disturbances are based on best professional judgment and
experience with this type of project. Components estimated include transmission support
structures; their associated construction pads; pulling sites for tensioning conductors; access
roads to each structure, communications station, and substation; staging areas; fly yards where
helicopter construction would be used; communications stations; and substations. As part of the
conceptual design and in order to aid quantification of effects, preliminary indicative locations
were assigned for all components of the Proposed Route and alternatives. Figure 2-1 through
Figure 2-3 illustrate how disturbance was estimated for each of the components. Sections 2.2
through 2.4 of this appendix describe typical disturbance areas for each construction activity.
The exact land requirements would depend on the final detailed design of the transmission line, which is influenced
by the terrain, land use, and economics. Alignment options may also slightly increase or decrease these values.
Assumptions/Notes:
1. ROW widths for 500-kV single circuit segments are 250 feet and 100 feet for 138/69-kV segments.
2. The staging areas would serve as field offices, reporting locations for workers, parking space for vehicles and equipment, sites
for material storage, fabrication assembly and stations for equipment maintenance, and concrete batch plants.
3. Staging/material storage yards/batch plants would be approximately 20 acres for 500 kV and located every 20 to 30 miles along
the line.
4. Fly yards would be 10 to 15 acres located every 5 miles. Values in table assume helicopter construction throughout all singlecircuit 500-kV segments. The construction contractor may choose to construct using ground-based techniques, therefore, not
utilizing fly yards for those sections.
5. For 500 kV, wiring pulling/splicing sites would be the ROW width x 600 to 900 feet located every 2 to 3 miles. Typically, the only
sites that would be off of the ROW would be at large angle dead-ends. It is estimated that one in four sites would be off of the
ROW.
28
November 2011
28
Transmission Line and Substation Components
Appendix B
1
2
Figure 2-1.
November 2011
Disturbance Area for Tower Structures
29
Transmission Line and Substation Components
1
Figure 2-2.
November 2011
Appendix B
Typical Disturbance Area
30
Transmission Line and Substation Components
Appendix B
1
2
Figure 2-3.
November 2011
Example Access Roads and Tower Locations
31
Transmission Line and Substation Components
Appendix B
1
2.2 Transmission Line Construction
2
3
4
5
6
7
8
The following sections detail the transmission line construction activities and procedures for the
304 miles of transmission lines and associated support structures, including 5.3 miles to be
rebuilt/relocated. Construction equipment and work force requirements are described in Section
2.6. Figure 2-4 illustrates the transmission line construction sequence. Substation construction
is described in Section 2.4. Various construction activities will occur during the construction
process, with several construction crews operating simultaneously at different locations. The
proposed construction schedule is described in Section 2.6.4 of this appendix.
9
10
Figure 2-4.
11
2.2.1 Transmission Line System Roads
12
13
14
15
Construction of the new transmission lines would require vehicle, truck, and crane access to
each new structure site for construction crews, materials, and equipment. Similarly, construction
of other Project components such as staging areas and substation sites would require vehicle
access.
16
17
18
19
20
21
Transmission line ROW access would be a combination of new access roads, improvements to
existing roads, and use of existing roads as is. Unimproved, overland travel routes will be
established in flat and moderate terrain where safe and practical. They may consist of existing
or new roads with minor grading or clearing; two track roads created by construction vehicles
driving directly over low growth vegetation and brush, leaving no defined roadway beyond
crushed vegetation; or any combination along the route. In some cases stumps or large root
November 2011
Transmission Line Construction Sequence
32
Transmission Line and Substation Components
Appendix B
1
2
3
4
5
6
7
8
wads will be removed with the aid of a bulldozer and surface restored with a grader. In steep
terrain new bladed access roads would be constructed using a bulldozer or grader, followed by
a roller to compact and smooth the ground. Front-end loaders will be used to move the soil
locally or off-site as necessary. Typically, access to the transmission line ROW and tower sites
requires a 14-foot-wide travel way for straight sections of road and a 16- to 20-foot-wide travel
way at corners to facilitate safe movement of equipment and vehicles. In steep, rugged terrain,
8-foot-wide all-terrain vehicle (ATV) trails may be established to facilitate permanent access for
off-road 4-wheel maintenance utility vehicles (UTVs).
9
10
11
12
13
14
15
Wherever possible existing roads will be used and new access roads would be constructed
within the proposed transmission line ROW. In other cases, new access roads would be
required between the proposed transmission line and existing roads outside of the ROW,
particularly in steep terrain where new bladed roads will often follow the contours to minimize
grades. Erosion control and sedimentation measures such as at-grade water bars, culverts,
sediment basins, or perimeter control would be installed as required to minimize erosion during
and subsequent to construction of the Project.
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
After Project construction, existing and new permanent access roads would be used by
maintenance crews and vehicles for inspection and maintenance activities. New roads created
to access tower sites would be revegetated but not restored to original contours in the event that
emergency access is needed to a tower location or for periodic inspection and maintenance
activities. Temporary construction roads not required for future maintenance access will be
restored after completion of Project construction. For example, access roads to staging areas
will not be required once the staging area is restored. Depending on Agency or landowner
preference, gates may be installed at fence crossings and other locations as requested to
restrict unauthorized vehicular access to the ROW. Roads retained for operations would be
seeded with an approved native grass mix and allowed to revegetate. For normal maintenance
activities, an 8-foot portion of the road would be used and vehicles would drive over the
vegetation. For non-routine maintenance requiring access by larger vehicles, the full width of the
access road may be used. Access roads would be repaired, as necessary, but not be routinely
graded. Vegetation (e.g., taller shrubs and trees) that may interfere with the safe operation of
equipment would be managed on a cyclical basis.
31
32
33
Table 2-3 lists the estimated miles of proposed off ROW access roads by county. The table will
be revised to show proposed locations of access roads once they are identified during the
design phase.
34
Table 2-3.
County
Morrow
Umatilla
Union
Baker
Malheur
Owyhee
Total
Miles of New and Improved off-ROW Access Roads
New Access Roads
(miles)
7.3
21.4
9.1
38.1
33.1
5.2
114.8
Existing Access Roads
to be Improved (miles)
2.2
15.6
28.1
44.8
50.9
23.5
165.1
35
November 2011
33
Total Miles
9.5
37.0
37.2
82.9
84.1
28.7
279.9
Transmission Line and Substation Components
Appendix B
1
2
3
Table 2-4 lists the estimated miles of proposed on and off road access roads. The table will be
revised to show any changes in the locations of access roads once they are identified during the
design phase.
4
Table 2-4.
County
Morrow
Umatilla
Union
Baker
Malheur
Owyhee
Total2
1
2
5
Miles of New and Improved Access Roads1
New
Access
Roads
Miles
37.3
44.2
27.4
72.6
69.0
12.2
262.7
Existing Access Roads
to be Improved
Miles
2.8
20.5
31.6
50.4
56.3
27.0
188.6
Totals
Miles
40.1
64.7
59.0
123.0
125.3
39.2
451.3
Includes on- and off-ROW access roads (including roads shown in Table 2-2).
Acreages in table are rounded to the nearest acre; column therefore may not sum exactly.
2.2.2 Soil Borings
6
7
8
9
10
11
12
13
At the discretion of the Project engineer, soil borings will be completed along the route to
determine depth to bedrock and the engineering properties of the soil. Based on the soil
properties, foundation designs will be completed for transmission line towers and other
structures. Borings would be made with truck- or track-mounted equipment. Access for
exploration drilling will be primarily overland travel with possible crushing of vegetation under
the vehicle; clearing/cutting of vegetation; temporary road building; road cuts or a combination
of these four types. In steep rugged terrain where overland access is not feasible, access by a
helicopter transported platform rig may be required.
14
15
The borings will be approximately 4 inches in diameter, range from 15 to over 60 feet deep, and
will be backfilled in accordance with State Water Resources Department rules.
16
2.2.3 Staging Areas
17
18
19
20
21
22
23
24
Construction of the Project will begin with the establishment of staging areas, or laydown yards.
The staging areas will serve as field offices; reporting locations for workers; parking space for
vehicles and equipment; and sites for material storage, fabrication assembly, concrete batch
plants, and stations for equipment maintenance. Staging areas, about 20 acres each for 500-kV
construction and 10 acres each for 138/69-kV construction, will be located approximately every
25 miles along the route. Additionally, fly yards for helicopter operations will be located
approximately every 10 miles along the route where helicopter construction is planned, and will
occupy approximately 10 to 15 acres.
25
26
27
28
29
30
Staging areas and helicopter fly yards will be fenced and their gates locked. Security guards will
be stationed where needed. Staging area locations will be finalized following discussion with the
land management agency or negotiations with landowners. In some areas, the staging area
may need to be scraped by a bulldozer and a temporary layer of rock laid to provide an allweather surface. Unless otherwise directed by the landowner, the rock will be removed from the
staging area upon completion of construction and the area will be restored.
31
32
Table 2-5 lists the frequency and estimated acreage disturbance for proposed staging areas
and helicopter fly yards by county. In locating yards, the preference is for relatively flat areas
November 2011
34
Transmission Line and Substation Components
Appendix B
1
2
3
with easy existing access to minimize site grading and new road construction. The staging
areas will be located in previously disturbed sites or in areas of minimal vegetative cover where
possible.
4
Table 2-5.
County
Morrow
Umatilla
Union
Baker
Malheur
Owyhee
Total
Construction Staging Areas and Helicopter Fly Yards
Staging Areas
Number
Acres
2
39.9
2
41.2
2
41.1
2
43.8
3
63.9
2
42.5
13
272.4
Fly Yards
Number
1
3
7
8
9
4
32
Acres
15.3
44.5
103.8
116.1
134.0
59.8
473.5
5
6
2.2.4 Site Preparation
7
8
9
10
11
12
13
14
15
16
Individual structure sites will be cleared to install the transmission line support structures and
facilitate access for future transmission line and structure maintenance. Clearing individual
structure sites will be done using a bulldozer to blade the required area. At each single-circuit
500-kV structure location, an area approximately 250 feet by 250 feet will be needed for
construction laydown, tower assembly, and erection at each tower site. This area will provide a
safe working space for placing equipment, vehicles, and materials. The work area will be
cleared of vegetation only to the extent necessary. For 138/69-kV structures the site prep area
will be approximately 100 feet by 100 feet. After line construction, areas not needed for normal
transmission line maintenance, including fire and personnel safety clearance areas, will be
graded to blend as near as possible with the natural contours, then revegetated as required.
17
18
19
20
21
22
23
Additional equipment may be required if solid rock is encountered at a structure location. Rockhauling, hammering, or blasting may be required to remove the rock. Excess rock that is too
large in size or volume to be spread at the individual structure sites will be hauled away and
disposed of at approved landfills or at a location specified by the landowner. Table 2-2 provides
the dimensions of each of the foundation holes required for each structure. See Section 1.1.1 of
this appendix for a description of each structure type and Figure 1-1 through Figure 1-3 for
structure illustrations.
24
2.2.5 Install Structure Foundations
25
Table 1-1 lists the number of and type of support structures that will be installed.
26
2.2.5.1 Lattice Steel Tower Foundations
Each 500-kV support structure will require the installation of foundations, which are typically
drilled concrete piers. First, four holes will be excavated for each structure. The holes will be
drilled using truck- or track-mounted augers of various sizes depending on the diameter and
depth requirements of the hole to be drilled. Each foundation will extend approximately 1 to 2
feet above the ground level.
27
28
29
30
31
32
33
34
35
2.2.5.2 H-Frame Installation
Each 500-kV H-frame will require the installation of drilled pier foundations. Two or three
foundations will be required per H-frame structures. The holes for each foundation will be drilled
using truck- or track-mounted augers of various sizes depending on the diameter and depth
November 2011
35
Transmission Line and Substation Components
Appendix B
1
2
3
requirements of the hole to be drilled. The diameter of each foundation will be approximately 7
to 8 feet at a depth of 30 to 40 feet. Each foundation will extend approximately 1 to 2 feet above
the ground level.
4
5
6
7
8
9
10
11
2.2.5.3 Monopole Installation
Tangent 138/69-kV monopole structures will require the poles to be directly embedded in the
ground. Holes will be drilled in the ground using a truck- or track-mounted auger. The diameter
of the hole excavated for embedment is typically between 5 and 6 feet (see Table 1-2). Depths
of the holes range from 15 to 25 feet deep. When the poles are placed in the holes, the hole will
be backfilled with native or select backfill. When backfill must be imported, material must be
obtained from commercial sources or from areas free of noxious weed species. See Section
1.1.1 of this appendix for a description a monopole structure and Figure 1-3 for an illustration.
12
13
14
15
16
Angle and dead-end 138/69-kV monopole structures will require the installation of drilled pier
foundations. The hole for each foundation will be drilled using a truck- or track-mounted auger of
various sizes depending on the diameter and depth requirements of the hole to be drilled. The
diameter of the foundation will be approximately 5 to 6 feet with at a depth of 20 to 25 feet deep.
Each drilled pier foundation will extend approximately one to two feet above the ground level.
17
18
19
20
21
22
Where solid rock is encountered, blasting (see Section 2.5.1 of this appendix), rock hauling, or
the use of a rock anchoring or micro-pile system may be required. Micro-piles are high capacity,
small diameter (5-inch to 12-inch) drilled and grouted in-place piles designed with steel
reinforcement to primarily resist structural loading. The rock anchoring or micro-pile system will
be used in areas where site access is limited or adjacent structures could be damaged as a
result of blasting or rock hauling activities.
23
24
25
26
27
28
In environmentally sensitive areas with very soft soils, a HydroVac, which uses water pressure
and a vacuum, may be used to excavate material into a storage tank. Alternatively, a temporary
casing may be used during drilling to hold the excavation open, after which the casing is
withdrawn as the concrete is placed in the hole. In areas where it is not possible to operate
large drilling equipment due to access or environmental constraints, hand digging may be
required.
29
30
31
32
33
34
Reinforced-steel anchor bolt cages will be installed after excavation and prior to structure
installation. These cages are designed to strengthen the structural integrity of the foundations
and will be assembled at the nearest Project laydown yard and delivered to the structure site via
flatbed truck or helicopter. These cages will be inserted in the holes prior to pouring concrete.
The excavated holes containing the reinforcing anchor bolt cages will be filled with concrete
(Table 1-2).
35
36
37
38
39
40
Typically, and because of the remote location of much of the transmission line route, concrete
will be provided from portable batch plants set up approximately every 25 miles along the line
route in one of the staging areas. Concrete will be delivered directly to structure sites in
concrete trucks with a capacity of up to 10 cubic yards. In the more developed areas along the
route and in proximity to the substations, the construction contractor may use local concrete
providers to deliver concrete to the site when economically feasible.
41
2.2.6 Erect Support Structures
42
43
44
45
46
The steel support structures will be assembled on site, except where helicopter delivery is
employed, as described in Section 2.5.2 of this appendix. Steel members for each structure will
be delivered to the site by flatbed truck. Assembly will be facilitated on site by a truck-mounted
crane. Subsequent to assembly, the structures will be lifted onto foundations using a large crane
designed for erecting towers. Where possible, the crane will move along the ROW from
November 2011
36
Transmission Line and Substation Components
Appendix B
1
2
structure to structure site erecting the towers, if access along the ROW is not possible the crane
will leave the ROW and use the access road network to reach the next structure.
3
4
5
6
7
8
9
The H-frame and monopole structures will be framed on site. Two methods of assembly can be
used to accomplish this, the first of which is to assemble the poles, braces, cross arms,
hardware, and insulators on the ground. A crane is then used to set the fully framed structure by
placing the poles in the excavated holes. Alternatively, aerial framing can be used by setting the
poles in the ground first and assembling the braces, cross arms, hardware, and insulators in the
air. Where possible, the crane will move along the ROW from structure to structure site setting
the structures.
10
2.2.7 String Conductors, Shield Wire, and Fiber Optic Ground Wire
11
12
13
14
15
Conductor, shield wire, and OPGW will be placed on the transmission line support structures by
a process called stringing. The first step to wire stringing will be to install insulators (if not
already installed on the structures during ground assembly) and stringing sheaves. Stringing
sheaves are rollers that are temporarily attached to the lower portion of the insulators at each
transmission line support structure to allow conductors to be pulled along the line.
16
Figure 2-5 illustrates the sequence of steps in installing conductors.
17
18
Figure 2-5.
19
20
21
22
23
24
Additionally, temporary clearance structures (also called guard structures) will be erected where
required prior to stringing any transmission lines. The temporary clearance structures are
typically vertical wood poles with cross arms and are erected at road crossings or crossings with
other energized electric and communication lines to prevent contact during stringing activities.
Bucket trucks may also be used to provide temporary clearance. Bucket trucks are trucks fitted
with a hinged arm ending in an enclosed platform called a bucket, which can be raised to let the
November 2011
Conductor Installation
37
Transmission Line and Substation Components
Appendix B
1
2
worker in the bucket service portions of the transmission structure as well as the insulators and
conductors without climbing the structure.
3
4
5
6
7
8
9
10
11
Once the stringing sheaves and temporary clearance structures are in place, the initial stringing
operation will commence with the pulling of a lightweight “sock” line through the sheaves along
the same path the transmission line will follow. Typically the sock line is pulled in via helicopter.
The sock line is attached to the hard line, which follows the sock line as it is pulled through the
sheaves. The hard line will then be attached to the conductor, shield wire, or OPGW to pull
them through the sheaves into their final location. Pulling the lines may be accomplished by
attaching them to a specialized wire stringing vehicle. Following the initial pulling of the wire into
the sheaves, the wire will then be tensioned to achieve the correct sag between support
structures.
12
13
14
15
16
17
18
19
20
21
22
23
24
Pulling and tensioning sites for 500-kV construction will be required approximately every 1.5 to
2 miles along the ROW and at angle points greater than 30 degrees and will require
approximately 5 acres at each end of the wire section to accommodate required equipment. The
138/69-kV pulling and tensioning sites will be required approximately every 1 to 2 miles along
the ROW and will require approximately 1.2 acres each to accommodate required equipment.
Equipment at sites required for pulling and tensioning activities will include tractors and trailers
with spooled reels that hold the conductors and trucks with the tensioning equipment. To the
extent practicable, pulling and tensioning sites will be located within the ROW. However, angle
points typically necessitate pulling and tensioning sites outside of the ROW. Depending on
topography, minor grading may be required at some sites to create level pads for equipment.
Finally, the tension and sag of conductors and wires will be fine-tuned, stringing sheaves will be
removed, and the conductors will be permanently attached to the insulators at the support
structures.
25
26
27
28
29
30
31
32
33
34
35
36
At the tangent and small angle structures, the conductors will be attached to the insulators using
clamps to “suspend” the conductors from the bottom of the insulators. At the larger angle deadend structures, the conductors cannot be pulled through and so they are cut and attached to the
insulator assemblies at the structure which “dead ends” the conductors. There are two primary
methods to attach the conductor to the insulator assembly at the dead-end structure. The first
method, hydraulic compression fittings, uses a large press and pump that closes a metal clamp
or sleeve onto the conductor. This method requires heavy equipment and is time consuming.
The second method, implosive fittings, uses explosives to compress the metal together.
Implosive fittings do not require heavy equipment, but do create noise similar to a loud
explosion when the primer is struck. The implosive type sleeve is faster to install and results in a
secure connection between the conductor and the sleeve. Implosive sleeves are planned for the
Project.
37
38
39
40
41
42
The 500-kV single-circuit line uses a three conductor bundle for each phase. At each singlecircuit 500-kV dead-end structure, 18 implosive dead-end sleeves (six per phase, one for each
of the three subconductors on each of the three phases, and on each side of the structure) will
be required. Additionally, 18 compression or implosive sleeves will be required to fabricate and
install the jumpers that connect the conductors from one side of the dead-end structure to the
other, for a total of 36 sleeves for each single-circuit dead-end structure.
43
44
45
46
The 138/69-kV double-circuit lines use a single-conductor bundle for each phase. Each of these
dead-end structures will require 12 implosive or compression type sleeves to dead-end the
conductors and 12 sleeves to fabricate the jumpers, for a total of 24 sleeves at each dead-end
structure. For the overall Project, approximately 8,000 to 10,000 implosive fittings will be used.
November 2011
38
Transmission Line and Substation Components
Appendix B
1
2.2.8 Cleanup and Site Reclamation
2
3
4
5
6
7
Construction sites, staging areas, material storage yards, pulling and tensioning yards, batch
plants and access roads will be kept in an orderly condition throughout the construction period.
Approved enclosed refuse containers will be used throughout the Project. Refuse and trash will
be removed from the sites and disposed of in an approved manner. Oils or chemicals will be
hauled to a disposal facility authorized to accept such materials. Open burning of construction
trash will not be allowed.
8
9
10
11
12
13
14
15
16
17
18
19
20
Disturbed areas not required for access roads and maintenance areas around structures will be
restored and revegetated, as required by the property owner or land management agency.
Service roads will be decompacted and the topsoil replaced. If a road prism was established it
will not be restored to original contours so that a stable road base is present if equipment is
needed to access a tower during operation. The landowner, land-management agency, or local
Natural Resources Conservation Service will be consulted regarding the appropriate seed mix
and rate to revegetate the road surface. Vegetation on an 8-foot width of road surface may be
periodically managed to allow equipment travel if necessary. Temporary culverts and bridges
will be removed. Drivable at-grade waterbars will be installed where needed with frequency
proportional to road slope to prevent erosion of the roadbed. Applicable agency BMPs and unit
management plan requirements will be implemented. All practical means will be made to restore
the land outside the minimum areas needed for safe operation to its original contour and to
restore natural drainage patterns along the ROW.
21
2.3 Communication System
22
23
24
OPGW for the communication system will be installed at the same time as the conductors on
each of the transmission line structures. It will be spliced and tensioned in the same way. The
AFL Telecommunications OPGW installation instructions will be used on this Project.
25
2.3.1 Communication Sites
26
27
28
29
30
31
Similar to the substations, the selected area is graded, vegetation is removed, and a layer of
crushed rock is installed. A pre-fabricated concrete communications shelter approximately 12foot by 32-foot by 9-foot tall will be constructed on the site. An emergency generator with a
liquid petroleum gas fuel tank will be installed at the site inside the fenced area. Two diverse
cable routes (aerial and/or buried) from the transmission ROW to the equipment shelter will be
installed.
32
2.3.2 Access Road
33
34
35
Communications station roads will be constructed using a bulldozer or grader, followed by a
roller to compact and smooth the ground. Front-end loaders will be used to move the soil locally
or off site. Typically, gravel will be applied to the prepared base layer.
36
2.4 Substation Construction
37
38
39
40
41
There are two substation construction scenarios. Scenario one assumes that the Grassland
Substation is built by PGE and only minor construction is required for the Project at this
substation and Hemingway Substation. In scenario two, IPC assumes the major construction of
the Grassland Substation and minor modifications within the fence line at Hemingway
Substation.
November 2011
39
Transmission Line and Substation Components
Appendix B
1
2.4.1 Substation Roads
2
3
4
Substation roads will be constructed using a bulldozer or grader, followed by a roller to compact
and smooth the ground. Front-end loaders will be used to move the soil locally or offsite. Either
gravel or asphalt will be applied to the prepared base layer.
5
2.4.2 Soil Borings
6
7
8
9
10
11
Typically, soil borings will be made at three to four locations in the substation, particularly at the
approximate location of large structures and equipment such as transmission line dead ends
and transformers, to determine the engineering properties of the soil. Borings will be made with
truck- or track-mounted equipment. The borings will be approximately 4 inches in diameter,
range from 15 to over 60 feet deep, and be backfilled with the excavated material upon
completion of soil sampling.
12
2.4.3 Clearing and Grading
13
14
15
16
17
Clearing of all vegetation will be required for the entire substation area, including a distance of
about 10 feet outside the fence. This is required for personnel safety due to grounding concerns
and because of lower clearances to energized conductors within the substations as compared
to transmission lines. These lower clearances are allowed by the NESC because the entire
substation is fenced.
18
19
20
21
22
23
24
25
26
27
28
An insulating layer on the surface of the substation is required to protect personnel from high
currents and voltages during electrical fault conditions. Typically, vegetation is removed and a 4to 6-inch layer of crushed rock is applied to the finished surface of the substation. Then the
substation is usually treated with a soil sterilizer to prevent vegetation growth because the
vegetation will degrade the insulating qualities of the crushed rock. The entire substation area
will be graded essentially flat, with just enough slope to provide for runoff of precipitation. The
substation will be graded to use existing drainage patterns to the extent possible. In some
cases, drainage structures, such as ditches, culverts, and sumps, may be required. Clearing
and grading material will be disposed of in compliance with local ordinances. Material from off
site will be obtained at existing borrow or commercial sites and will be trucked to the substation
using existing roads and the substation access road.
29
2.4.4 Storage and Staging Yards
30
31
32
33
Construction material storage yards may be located outside the substation-fenced area near the
substation. These storage yards may be part of the substation property or leased by the
contractor. After construction is completed, all debris and unused materials will be removed and
the staging/storage yards returned to preconstruction conditions by the construction contractor.
34
2.4.5 Grounding
35
36
37
38
39
40
A grounding system is required in each substation for detection of faults and for personnel
safety. The grounding system typically consists of buried copper conductor arranged in a grid
system and driven ground rods, typically 8 to 10 feet long. The ground rods and any equipment
and structures are connected to the grounding conductor. The amount of conductor and length
and number of ground rods required are calculated based on fault current and soil
characteristics.
41
2.4.6 Fencing
42
43
44
45
Security fencing is installed around the entire perimeter of each new or expanded substation to
protect sensitive equipment and prevent accidental contact with energized conductors by third
parties. This 7-foot-high fence will be constructed of chain link with steel posts. One foot of
barbed wire or other similar material is installed on top of the chain link yielding a total fence
November 2011
40
Transmission Line and Substation Components
Appendix B
1
2
height of 8 feet. Locked gates will be installed at appropriate locations for authorized vehicle and
personnel access.
3
2.4.7 Foundation Installation
4
5
6
7
8
9
10
11
12
Foundations for supporting structures are of two types—spread footings or drilled piers. Spread
footings are placed by excavating the foundation area, placing forms and reinforced-steel and
anchor bolts, and pouring concrete into the forms. After the foundation has been poured, the
forms will be removed, and the surface of the foundation dressed. Pier foundations are placed in
a hole generally made by a truck-mounted auger. Reinforced-steel and anchor bolts are placed
into the hole using a truck-mounted crane. The portion of the foundation above ground will be
formed. The portion below ground uses the undisturbed earth of the augered hole as the form.
After the foundation has been poured, the forms will be removed, the excavation will be
backfilled, and the surface of the foundation dressed.
13
14
15
16
17
18
19
20
21
22
23
Equipment foundations for circuit breakers and transformers will be slab-on-grade type. These
foundations are placed by excavating the foundation area; placing forms, reinforced steel, and
anchor bolts (if required); and placing concrete into the forms. After the foundations have been
poured, the forms will be removed, and the surface of the foundation dressed. Where
necessary, provision will be made in the design of the foundations to mitigate potential problems
due to frost. Reinforced steel and anchor bolts will be transported to each site by truck, either as
a prefabricated cage or loose pieces, which will then be fabricated into cages on the site.
Concrete will be hauled to the site in concrete trucks. Excavated material will be spread at the
site or disposed of in accordance with local ordinances. Structures and equipment will be
attached to the foundations by means of threaded anchor bolts embedded in the concrete.
Some equipment such as transformers and reactors may not require anchor bolts.
24
2.4.8 Oil Containment
25
26
27
28
29
30
31
32
33
34
Some types of electrical equipment, such as transformers and some types of reactors and
circuit breakers are filled with an insulating mineral oil. Containment structures are required to
prevent equipment oil from getting into the ground or waterbodies in the event of a rupture or
leak. These structures take many forms depending on site requirements, environmental
conditions, and regulatory restrictions. The simplest type of oil containment is a pit, of a
calculated capacity, under the oil-filled equipment that has an oil-impervious liner. The pit is
filled with rock to grade level. In case of an oil leak or rupture, the oil captured in the
containment pit is pumped into tanks or barrels and transported to a disposal facility. If required,
more elaborate oil containment systems can be installed. This may take the form of an on- or
off-site storage tank and/or oil-water separator equipment depending on site requirements.
35
2.4.9 Structure and Equipment Installation
36
37
38
39
40
41
42
43
44
Supporting steel structures are erected on concrete foundations as noted above. These are set
with a truck-mounted crane and attached to the foundation anchor bolts by means of a steel
base plate. These structures will be used to support the energized conductors and certain types
of equipment. This equipment is lifted onto the structure by means of a truck-mounted crane
and bolted to the structures; electrical connections are then made. Some equipment, such as
transformers, reactors, and circuit breakers, are mounted directly to the foundations without
supporting structures. These are set in place by means of a truck-mounted crane. Some of this
equipment requires assembly and testing on the pad. Electrical connections to the equipment
are then made.
November 2011
41
Transmission Line and Substation Components
1
2
3
4
5
6
7
8
Appendix B
2.4.9.1 Control Building Construction
One or more control buildings are required at each substation to house protective relays, control
devices, battery banks for primary control power, and remote monitoring equipment. The size
and construction of the building depends on individual substation requirements. Typically, the
control building will be constructed of concrete block, pre-engineered metal sheathed, or
composite surfaced materials. Once the control house is erected, equipment is mounted and
wired inside. In some cases an emergency generator may be located just outside the control
house within the substation fenced area.
10
11
12
13
14
15
2.4.9.2 Conductor Installation
The two main types of high voltage conductors used in substations are tubular aluminum for
rigid bus sections and/or stranded aluminum conductor for strain bus and connections to
equipment. Rigid bus will be a minimum of 4 inches in diameter for this Project and will be
supported on porcelain or polymer insulators on steel supports. The bus sections will be welded
together and attached to special fittings for connection to equipment. Stranded aluminum
conductors will be used as flexible connectors between the rigid bus and the station equipment.
16
2.4.10 Conduit and Control Cable Installation
17
18
19
20
21
Most substation equipment requires low-voltage connections to protect relaying and control
circuits. These circuits allow metering, protective functions, and control (both remote and local)
of the power system. Connections are made from the control building to the equipment through
multi-conductor control cables installed in conduits and/or pre-cast concrete cable trench
system.
22
2.4.11 Construction Cleanup and Landscaping
23
24
25
26
27
28
The cleanup operation will be performed after construction activities are completed. All waste
and scrap material will be removed from the site and deposited in local permitted landfills in
accordance with local ordinances. Ruts and holes outside the substation fence due to
construction activities will be regraded. Revegetation and restoration will be conducted as
required. Landscaping required by the permitting agency will use drought-tolerant plant
materials. A permanent access road will be constructed to the new substation.
29
2.5 Special Construction Techniques
30
2.5.1 Blasting
31
32
33
34
35
36
37
38
39
40
41
42
As described in Section 2.2.5 of this appendix, 500-kV lattice tower, H-frame structure and
138/69-kV angle and dead-end structure foundations will normally be installed using drilled
shafts or piers and 138/69-kV tangent structures will be directly embedded. If hard rock is
encountered within the planned drilling depth and rock coring is not economically viable,
alternative foundation systems, such as micropile or rock anchor supported “pile caps” may be
required to provide axial upward and downward resistance in addition to sliding and overturning
resistance. Areas where relatively shallow rock is located has been identified based on the
geologic setting of the proposed alignment. Table 2-6 summarizes the relatively shallow bed
rock conditions along the Proposed Route as determined from the U.S. Natural Resources
Conservation Service (NRCS) soil database and regional geologic maps. More precise locations
where these specialty foundation systems may be required will be identified based on sitespecific geotechnical studies carried out as part of detailed design.
9
November 2011
42
Transmission Line and Substation Components
1
Table 2-6.
Total
Miles
304
Appendix B
Summary of Shallow Bedrock
Route Miles within
1 to 4 feet of
Shallow Bedrock
164
Route Miles
within 4 to 8 feet
of Shallow
Bedrock
120
Route Miles
within 8 to 12 feet
of Shallow
Bedrock
20
Percent of
Proposed Route
Miles Within
Shallow Bedrock
100
2
3
4
5
6
7
8
9
The construction contractor will be required to prepare an overall Blasting Plan for the Project,
subject to the approval of IPC. The Blasting Plan will detail the contractor’s proposals for
compliance with IPC’s blasting specifications and will detail the general concepts proposed to
achieve the desired excavations using individual shot plans. In addition, the plan will address
proposed methods for controlling fly rock, for blasting warnings, and for use of non-electrical
blasting systems. The contractor will be required to provide data to support the adequacy of the
proposed efforts regarding the safety of structures and slopes and to ensure that an adequate
foundation is obtained. When utilized, blasting will take place between sunrise and sunset.
10
11
12
13
The shot plans will detail, including sketches, the drilling and blasting procedures; the number,
location, diameter, and inclination of drill holes; the amount, type, and distribution of explosive
per hole and delay; and pounds of explosive per square foot for presplitting and smooth
blasting. The contractor will be required to maintain explosives logs.
14
15
16
17
Blasting near buildings, structures, and other facilities susceptible to vibration or air blast
damage will be carefully planned by the contractor and IPC and controlled to eliminate the
possibility of damage to such facilities and structures. The Blasting Plan will include provisions
for control to eliminate vibration, fly rock, and air blast damage.
18
19
20
21
22
Blasting will be very brief in duration (milliseconds), and the noise will dissipate with distance.
Blasting produces less noise and vibration than comparable non-blasting methods to remove
hard rock. Non-blasting methods include track drill rigs, rock breakers, jack hammers, rotary
percussion drills, core barrels, and rotary rock drills with rock bits. Which all require much longer
time duration to excavate approximately the same amount of rock as blasting.
23
24
25
Table 2-6 indicates that 100 percent of the route is within shallow bedrock. However, some
bedrock may be soft enough to accommodate soil drilling methods to construct foundations. The
bedrock characteristics will be more completely determined by on-site geotechnical testing.
26
27
28
29
30
31
32
33
34
Micropiles are high-capacity, small-diameter steel casing that are drilled into place, reinforced
with an internal structural bar, and pressure grouted. The grout creates a bond between the
interior casing wall and structural bar, as well as the external casing wall and the rock.
Micropiles are installed using water flush rotary drilling or rotary percussion drilling techniques.
This can be done remotely and requires a limited amount of disturbance and ground clearing.
Each pile measures between 6 and 12 inches in diameter and micropiles consistently achieve
capacities of 60 to 100 tons, with special installations of up to 200 tons. Drilled micropiles offer
excellent axial up and down capacity in hard rocks, with the added advantage of capability of
helicopter importing the micropile drill rig.
35
36
37
38
39
40
Rock anchors supporting a foundation “pile cap” is most advantageous when the rock is very
hard and very shallow. It consists of two parts; a foundation “pile cap” in addition to anchor bars
embedded in the grouted or epoxy anchor holes. The top part of the bar is embedded in the
concrete of the “pile cap”. The depth of embedment, diameter and number of anchor bars will
depend upon the uplift, moment and sliding force on the “pile cap”. The determination of
whether a rock formation is suitable for installation of rock anchors is a geotechnical
November 2011
43
Transmission Line and Substation Components
Appendix B
1
2
3
4
5
determination based on rock quality. Since the bearing capacity of rock is usually much greater,
geotechnical assessments would center around designing for uplift. The rock surfaces may be
roughened grooved or shaped to increase the uplift capacity, depending on the final “pile cap”
configuration. This system may also be considered with the use of epoxy grout anchors to
facilitate a tidy construction area.
6
2.5.2 Helicopter Use
7
8
9
10
11
12
13
14
15
16
Access roads are required to each tower site for construction and for operation and
maintenance activities. Helicopters may be used to support these activities. Project construction
activities potentially facilitated by helicopters may include delivery of construction laborers,
equipment, and materials to structure sites; structure placement; hardware installation; and wire
stringing operations. Helicopters may also be used to support the administration and
management of the Project by IPC. Where construction access by truck is not practical due to
steep terrain, ATV trails may be utilized to support maintenance activities. The use of helicopter
construction methods for this Project will not change the length of the access road system
required for operating the Project because vehicle access is required to each tower site
regardless of the construction method employed.
17
18
19
20
21
22
23
The typical single-circuit 500-kV towers weigh approximately 25,000 pounds and in some cases
it may be desirable to employ heavy lift helicopters in the tower erection process. To allow the
construction contractor flexibility in construction methods, the construction specification will be
written to allow the contractor the option of using ground-based or helicopter construction
methods, or a combination thereof. Use of a helicopter for structure erection may be driven by
various factors, including access to the structure locations, construction schedule, and/or
construction economics.
24
25
26
27
28
29
30
31
32
When helicopter construction methods are employed, helicopter construction activities will be
based at a fly yard, which is a Project-material staging area (see Table 2-5). The fly yards will
be approximately 10 to 15 acres in area and will be sited at locations to permit a maximum fly
time of 4 to 8 minutes to reach structure locations, typically at about 10-mile intervals. Fly yards
will be used for material storage and erection of structure sections prior to transport to the final
structure locations for installation. Additionally, fueling trucks, maintenance trucks, and
operations crews will be based in the fly yards. Appropriate dust control measures will be
implemented at these fly yard locations as well as the locations where helicopters will be used
along the route.
33
34
35
36
37
38
Prior to installation, each tower structure will be assembled in multiple sections at the fly yard.
Tower sections or components will be assembled by weight based on the lifting capacity of the
helicopter in use. The lift capacity of helicopters is dependent on the elevation of the fly yard,
the tower site, and the intervening terrain. The heavy lift helicopters that could be used to erect
the single-circuit 500-kV tower sections will be able to lift a maximum of 15,000 to 20,000
pounds per flight, depending on elevation.
39
40
41
42
43
44
After assembly at the fly yard, the tower sections will be attached by cables from the helicopter
crane to the top four corners of the structure section and airlifted to the structure location. Upon
arrival at the structure location, the section will be placed directly on to the foundation or atop
the previous structure section. Guide brackets attached on top of each section will assist in
aligning the stacked sections. Once aligned correctly, line crews will climb the structures to bolt
the sections together permanently.
45
46
47
It should be noted that the fly yard locations provided are considered approximate and subject
to change, additions, or deletions upon acquisition of an installation contractor prior to the
beginning of construction. Upon completion of field review, a final determination will be made on
November 2011
44
Transmission Line and Substation Components
Appendix B
1
2
the necessity of certain fly yards and the respective locations that provide the most efficient,
economic, safest, and least impact use of the fly yards that are needed.
3
2.5.3 Water Use
4
5
6
7
8
Construction of the transmission lines and substations will require water. Major water uses are
for transmission line structure and substation foundations, and dust control during ROW and
substation grading and site work. A minor use of water during construction will include the
establishment of substation landscaping where required. Table 2-7 lists the estimated amount of
water required for the Project by County.
9
Table 2-7.
County
Morrow
Umatilla
Union
Baker
Malheur
Owyhee
Estimated Water Usage for Construction by County
Foundation
Construction
(gallons)
350,000
450,000
300,000
600,000
550,000
200,000
Substation
(gallons)
263,500
NA
NA
NA
NA
301,000
Communication
Sites (gallons)
400
400
700
400
1,100
0
Dust
Abatement
(gallons)
1,400,000
1,500,000
1,200,000
2,300,000
2,200,000
750,000
Total, All
Uses
(gallons)
2,013,900
2,000,000
1,500,000
2,900,000
2,800,000
1,251,000
10
11
12
13
14
15
16
Transmission lines use water for two primary purposes: foundation construction and ROW dust
control. The required water will be procured from municipal sources, from commercial sources,
or under a temporary water use agreement with landowners holding existing water rights. No
new water rights will be required. In the construction of foundations, water is transported to the
batch plant site where it will be used to produce concrete. From the batch plant the wet concrete
will be transported to the structure site in concrete trucks for use in foundation installation (refer
to Section 2.2.4 for more details on foundation installation).
17
18
19
20
Construction of the transmission lines and related facilities will generate a temporary increase in
fugitive dust. If the level of fugitive dust is too high in specific Project areas, as determined in
cooperation with the landowner or agency, water will be applied to disturbed areas to minimize
dust.
21
22
23
24
25
Water usage for substation construction is primarily for dust control during site preparation work.
During this period, construction equipment will be cutting, moving, and compacting the subgrade
surface. As a result, water trucks patrolling the site to control dust will make as many as one
pass per hour over the station site. Once site preparation work is complete, concrete for the
placement of foundations becomes the largest user of water and dust control becomes minimal.
26
27
28
Once site grading is complete, the balance of the substation construction work will be performed
on bare subgrade soil or subgrade with a thin layer of rock. Fire risk will be minimal due to the
bare ground or rock surface and will be contained within the confines of station fenced area.
29
2.6 Construction Elements
30
31
32
For the construction element section, much of the schedule and manpower discussion is based
on division of the project into two spreads of equal length. This was done to show that different
labor forces will be working independently in different parts of the Project.
November 2011
45
Transmission Line and Substation Components
1
Appendix B
2.6.1 Construction Workforce
2
3
4
5
6
7
8
9
10
11
The proposed Project will be constructed primarily by contract personnel, with IPC responsible
for Project administration and inspection. The construction workforce will consist of laborers,
craftsmen, supervisory personnel, support personnel, and construction management personnel
who will perform the construction tasks. Estimated construction workforce requirements are
summarized by Engineering, Procurement, and Construction (EPC)8 spread9 in Table 2-8.
These projections were developed for the various Project components by IPC’s transmission
engineering contractor using project planning computer software. Overall, Project construction is
expected to occur between 2014 and 2016, with multiple contractors working concurrently on
different portions of the route and substations of the Project to meet the planned in-service
dates.
12
Table 2-8.
Projected Workers and Population Change during Peak Construction
Construction Spread
Workers
Commute to the Job Site Daily
Move to the Project Area alone
Move to the Project Area with family
Total
1
61
164
18
243
2
63
169
19
251
13
14
15
16
17
18
19
20
IPC’s proposed schedule identifies general construction timeframes for the transmission line
and substations, generally 2 to 2.5 years. Project-wide, the workforce will reach a peak of
approximately 300 to 350 workers in the late summer months in 2014 and 2015. The
construction personnel peak on site in any portion of the route will be when the wire stringing
operations begin while several other operations are occurring at the same time, which includes
foundation installation, hauling materials, assembling structures, and erecting/setting structures.
Due to snowfall at the higher elevations, the workforce will be slightly lower in the winter
months.
21
22
23
24
25
With respect to each substation, installation of the ground grid, installation of the conduit and
cable trench system, assembly and erection of steel structures, construction of the control
building, and installation of major equipment will start when the foundations are 50 percent
complete and will overlap with each other, resulting in the highest concentration of the work
force on site.
26
27
28
29
30
31
32
33
34
35
36
37
The substation work is estimated to take between 40 and 60 personnel at each site. Site
grading requires a small number of people including a surveyor, heavy equipment operators,
foreman, and construction management personnel. Each station will require numerous concrete
crews in order to complete the below grade construction and concrete placement on schedule.
Concrete will be provided by a batch plant producing approximately 150 cubic yards per day
delivered in 8- to 10-cubic yard trucks. Other below-grade crews will be needed to install
conduit, cable trench, and ground mat material. The below-grade crews will be on site
overlapping the schedule of the concrete crew. Several three-man crews working with boom
trucks and bucket trucks will erect the steel and install the physical equipment in the yard.
Considering the size of the substation expansions, this will require approximately three fully
equipped crews per station. Electrical installation will be handled by 20 men arranged into twoman teams alternating between indoor and outdoor activity. Construction will generally occur
8
EPC contract means that the final engineering, all or some of the procurement, and the construction are performed by one
contractor.
9
A spread is a geographic segment within which a complete construction sequence will be executed.
November 2011
46
Transmission Line and Substation Components
Appendix B
1
2
between 7 a.m. and 7 p.m., Monday through Saturday. Additional hours may be necessary to
make up schedule deficiencies or to complete critical construction activities.
3
2.6.2 Construction Equipment and Traffic
4
5
6
7
8
9
10
Equipment required for construction of the Project transmission lines and substations will
include, but is not limited to, that listed in Table 2-9 and Table 2-10. The Hemingway Substation
is an existing substation planned for the minor Project additions within the existing fence line.
Table 2-10 includes construction equipment requirements for both substations. These tables
also include the anticipated daily duration of equipment use for each type. Table 2-11 provides
an estimate of the average and peak construction traffic during the construction period by
spread.
11
12
13
Construction access will occur at several locations along the transmission line route, resulting in
dispersed construction traffic. Truck deliveries will normally be on weekdays between 7:00 a.m.
and 7:00 p.m.
14
Table 2-9.
Transmission Line Construction Equipment Requirements
Equipment
Pickup
Bulldozer
Motor Grader
Water Truck
Hole Digger
Truck (2-ton)
Concrete Truck
Carry All
Crane
Steel Haul Truck
Fork Lift
Wire Reel Trailer
Diesel Tractor
Boom Truck (5-ton)
Splicing Truck
3-Drum Puller
Single Drum Puller
Tensioner
Sagging Dozer
Static Wire Reel Trailer
Dump Truck
Loader
Helicopter2
15
16
17
18
Qty.
10
3
2
2
2
3
4
12
7
2
3
6
5
3
2
2
2
2
2
2
2
3
1
Spread 11
hrs/ day days/ wk
8
6
4
6
4
6
6
6
8
6
5
6
6
6
6
6
7
6
7
6
6
6
7
6
5
6
6
6
3
6
4
6
3
6
4
6
3
6
5
6
4
6
4
6
6
6
1
Qty.
10
3
2
2
2
3
4
12
7
2
3
6
5
3
2
2
2
2
2
2
2
3
1
Spread 2
hrs/ day days/ wk
8
6
4
6
4
6
6
6
8
6
5
6
6
6
6
6
7
6
7
6
6
6
7
6
5
6
6
6
3
6
4
6
3
6
4
6
3
6
5
6
4
6
4
6
6
6
Project divided into two segments of approximately equal length.
For structures which can only be set by helicopter, or if the contractor elects to erect structures by helicopter, one or
more heavy lift helicopters would be required.
2
November 2011
47
Transmission Line and Substation Components
1
Table 2-10.
Equipment Requirements for Grassland and Hemingway Substations
Equipment
Auger
Backhoe
Front Loader
Ditch Witch
Concrete Truck
Water Truck
Dump Truck
Trailer
Crew Truck/Car
Hauler
Skid Steer Loader
Batch Plant
Drill Rig
Truck with Trailer
Compressor
Construction Fork
980 Loader
Vibrating Roller
Light Pickup
Crane
Bucket Truck
Boom Truck
Trailer
Fork Lift
Overhead Line Rig
1
2
Appendix B
Grassland Substation 1
Qty.
Hrs/Day Days/Wk
10
10
6
2
10
6
1
10
6
2
10
6
10
10
6
1
10
6
1
10
6
2
10
6
4
10
6
1
10
6
1
10
6
1
10
6
1
10
6
4
10
6
2
10
6
1
10
6
1
10
6
1
10
6
1
10
6
1
10
6
2
10
6
2
10
6
1
10
6
1
10
6
1
10
6
Hemingway Substation2
Qty.
Hrs/Day
Days/Wk
0
10
6
1
10
6
0
10
6
0
10
6
0
10
6
1
10
6
0
10
6
0
10
6
1
10
6
0
10
6
0
10
6
0
10
6
0
10
6
0
10
6
1
10
6
1
10
6
0
10
6
0
10
6
1
10
6
1
10
6
1
10
6
1
10
6
0
10
6
1
10
6
1
10
6
The equipment requirements for the Grassland Substation only apply if IPC builds this substation.
The equipment requirements for the Hemingway Substation expansion are only for work within the fence line.
2
3
November 2011
48
Transmission Line and Substation Components
1
Table 2-11.
Appendix B
Average and Peak Construction Traffic (per spread)
Vehicle Type
Spread 1
Construction Workers
Delivery
Heavy Trucks
Water Trucks
Total
Spread 2
Construction Workers
Delivery
Heavy Trucks
Water Trucks
Total
Grassland Substation
Construction Workers
Delivery
Heavy Trucks
Water Trucks
Total
Hemingway Substation
Construction Workers
Delivery
Heavy Trucks
Water Trucks
Total
Average Daily Round Trips
Peak Daily Round Trips
18
2
10
2
32
28
4
15
4
51
18
2
10
2
32
28
4
15
4
51
8
5
15
6
34
24
10
30
12
72
5
3
8
2
18
7
5
12
4
28
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
The equipment required for transmission line construction is similar for both the 500-kV and
69/138-kV lines, although the equipment needed for smaller voltage lines construction is
generally smaller than for 500-kV construction. The following is a summary of anticipated
equipment to be used for each construction activity. Survey work only requires the use of pickup
trucks or ATVs. Road construction will utilize pickups, bulldozers, motor graders, and water
trucks. To dig holes and install the directly embedded structures or install 500-kV foundations it
is anticipated that pickup trucks, 2-ton trucks, hole diggers, bulldozers, concrete trucks, water
trucks, carry alls, cranes, hydro crane, wagon drill, dump trucks, and front-end loaders will be
used. Hauling lattice steel members, tubular poles, braces and hardware to the structure sites
will require the use of steel haul trucks; carry alls, cranes, and forklifts. For assembly and
erection of structures it is anticipated that pickup trucks, 2-ton trucks, carry alls, cranes, and a
heavy lift helicopter may be used. Wire installation requires the most equipment including
pickups, wire reel trailers, diesel tractors, cranes, 5-ton boom trucks, splicing trucks, three drum
pullers, single drum pullers, tensioners, sagging dozers, carry alls, static wire reel trailers, and a
light helicopter. Final cleanup, reclamation, and restoration will utilize pickups, 2-ton trucks,
bulldozers, motor graders, dump trucks, front-end loaders, and water trucks. The highest level
of traffic will be when the wire stringing operations begin while several other operations are
occurring at the same time which will likely include excavating holes, installing foundations,
hauling steel, assembling structures, and erecting structures.
21
22
23
For the substation work, the highest level of traffic will be during site grading and foundation
installation. It is estimated that 2,000 to 4,000 cubic yards of topsoil will not be suitable for reuse at the Grassland Substation site and will have to be disposed of at an authorized off-site
November 2011
49
Transmission Line and Substation Components
1
2
3
4
5
6
7
8
9
Appendix B
location. Dump trucks will be leaving and returning to the site on a constant basis each day for
the duration of the site grading. Each site will require between 4,000 and 7,000 cubic yards of
concrete. Delivering, placing, and finishing concrete is labor intensive. Once concrete placement
is complete, traffic on the surrounding roads will subside. Workers will arrive in the morning and
leave at the end of the day. The balance of daily traffic will be material deliveries from
storerooms, which will probably be one or two trips per day. Each substation will require the
delivery of permitted loads such as transformers and/or reactors. Each reactor or transformer
bank required will require four large multiple-wheel lowboy trucks. Delivery will be scheduled to
match the completion of their respective foundations.
10
2.6.3 Removal of Facilities and Waste Disposal
11
12
13
14
15
16
17
Substation and ROW construction will generate a variety of solid wastes including concrete,
hardware, and wood debris. The solid wastes generated during construction will be recycled or
hauled away for disposal. Excavation along the ROW and at substations will generate solid
wastes that could potentially be used as fill; however, some of the excavated material will be
removed for disposal. Excavated material that is clean and dry will be spread along the ROW.
The volumes shown in Table 2-12 reflect the waste that will be hauled away and not disposed of
in the ROW for each segment during construction of the Project.
18
Table 2-12.
County
Morrow
Umatilla
Union
Baker
Malheur
Owyhee
Solid Waste Generation from Construction Activities
Transmission Line
Imported
Solid
Native
Waste
Material
Total2
Total1
(cu. yard) (cu. yard)
1,800
700
1,900
800
1,600
700
2,900
1,200
2,800
1,200
1,000
400
Communication Sites
Imported
Native
Solid
Material
Waste
Total1
Total2
(cu. yard) (cu. yard)
100
10
110
10
200
20
100
10
330
30
0
0
Substation
Native
Material
Total1
(cu. yard)
2,000
NA
NA
NA
NA
400
Imported
Solid Waste
Total2
(cu. yard)
200
NA
NA
NA
NA
100
19
20
21
22
23
24
25
26
1
27
28
29
30
31
32
33
The majority of waste associated with substation construction results from spoils created during
site grading. The values shown in Table 2-12 reflect the amount of vegetation and rock larger
than 6 inches in diameter that cannot be processed and converted into backfill for compaction.
Very little of the soil excavated during foundation installation is waste product. Above-grade
waste will be packing material such as crates, pallets, and paper wrapping to protect equipment
during shipping. It is assumed a 12-yard dumpster will be filled once a week with waste material
for the duration of each substation project.
34
2.6.4 Construction Schedule
35
36
IPC intends to continue to refine the design of the Project during the BLM approval process in
order to immediately commence construction if the Project is approved. Final engineering
Native materials consist of stripped vegetation, excess soil, large rocks, or other natural materials that cannot be reused on-site.
This was assumed at approximately 10% of excavation. Native materials may be suitable for disposal at fill dirt sites, or County
Construction and Demolition landfills, as approved by local entities.
2
Imported solid waste is non-hazardous refuse delivered to the Project, such containers, boxes, bags, sacks, packing materials,
broken insulators, scrap conductor, empty wire spools, and other miscellaneous non-hazardous paper, plastic or similar materials.
These are materials that will be recycled, hauled directly, or placed in a dumpster or roll-off for disposal at a municipal solid waste
landfill, as approved by local entities.
November 2011
50
Transmission Line and Substation Components
Appendix B
1
2
3
4
5
6
7
8
9
10
surveys will determine the exact locations of towers, access roads, and other features prior to
the start of construction and will be included in the Plan of Development. Due to the broad
scope of construction, the varied nature of construction activities, and the geographic diversity
of the Project area, IPC intends to hire multiple contractors to complete Project work within the
projected timeframe and in accordance with industry performance standards. The Proposed
Action will involve one EPC contracts with two construction spreads for the transmission line
and division of the Project into discrete construction phases. Each portion of the route will be
under construction at the same time. IPC developed a Project construction schedule based on
this strategy. Figure 2-6 provides a general schedule, showing preliminary construction
schedule time frames.
11
12
13
14
15
16
17
Although the construction rate of progress will be reduced in the winter, IPC has planned an
aggressive schedule and it is anticipated that construction will continue through the winter
months in the lower-elevation areas of the Project, except during winter storms. In the higherelevation areas of the Project, winter storms and snow will limit access to the ROW, for example
in the Blue Mountains. In these areas, it is expected that construction will be suspended on
some portions of the ROW during the peak winter months and construction resources will either
be demobilized or shifted to other portions of the Project.
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
Transmission line construction commences with contractor mobilization. The contractor will
mobilize equipment and personnel to the construction site at various stages in the Project
schedule depending on operational requirements. This will cumulatively require approximately
30 days throughout the schedule for each segment. Construction management, engineering
support, inspection, materials handling, and administration are required throughout the Project.
First, surveyors will start at one end of the route and stake the locations of access roads. Road
construction can start 1 to 2 weeks after the surveyors begin, which may require clearing in
higher elevations where tree removal is required prior to road construction. After a couple of
weeks of road construction another survey crew can begin staking the structure locations. A
week or two after the survey crew starts staking structure locations, excavation of holes for
foundations for 500-kV towers, or for directly embedded poles for smaller voltage structures,
can begin. For 500-kV construction, the installation of the concrete pier foundations will begin
within the next couple of weeks. The foundations need time to cure and develop to full structural
strength (measured by compressive strength) before lattice towers can be installed. Five to six
weeks after foundation installation has begun, lattice tower assembly and erection can begin.
For 138/69-kV construction, structure assembly and setting can begin immediately after the
excavation of holes has begun. The wire installation crews will start approximately 8 to 12
weeks after assembly and erection/setting begins. This will be followed by final cleanup,
reclamation, and restoration.
37
November 2011
51
Transmission Line and Substation Components
Appendix B
1
2
Figure 2-6.
Project Construction Schedule
3
November 2011
52
Transmission Line and Substation Components
1
2
3
4
5
6
7
8
Appendix B
Substation construction includes five activities: 1) site grading (grading and access road
development), 2) below-grade construction (primarily the installation of foundations, 3) abovegrade construction (steel erection and building construction), 4) electrical (installation and
termination of control wiring), and 5) testing (functional testing of control and monitoring
schemes). Typically, these activities overlap and complement each other, allowing the
construction of a substation to proceed more quickly than line construction. It is estimated that
the site grading activity and access road work for Grassland and Hemingway substations will
take 4 to 8 weeks to complete, depending on the size of the site.
9
10
11
12
Below-grade construction can be completed in 3 months or less for the Hemingway Substation.
In this case, the basic infrastructure is already in place, having been installed with the initial
substation and designed for the future expansion requirements. If the Grassland Substation is
not constructed ahead of the Project and full buildout is required, the duration will be longer.
13
14
15
16
17
18
19
20
21
22
23
24
25
Above-grade construction duration is highly dependent on the level of construction force the
contractor chooses. For the substation expansions at Grassland or Hemingway Substations, it is
estimated that erection of steel, bus assembly, and major equipment assembly will take up to
9 months. Due to the size of each station, many crews can work on steel erection and
equipment assembly without interfering with each other. The greatest amount of schedule
recovery or acceleration in a station’s construction schedule can be achieved during this
timeframe. Electrical construction is a long and labor-intensive task. Although multiple crews
can work in a yard at any given time, the space in a control building is very limited and will
determine the length of this task. In the case of each of these stations, given the size and type
of equipment to be installed, there will be miles of cable to be pulled into conduit and duct banks
and thousands of connections to be made and double checked prior to the start of testing. New
substations will take longer than existing substations that already have the basic infrastructure
in place.
26
27
28
29
30
31
Prior to starting construction, IPC may be required to conduct on-site surveys in accordance
with applicable protocols or mitigation measures adopted by BLM and other agencies as Project
conditions. Accordingly, adjustments might occur to the Project schedule as necessary to avoid
sensitive resources. Pre-construction activities, including pre-construction environmental
surveys, materials procurement, design, contracting, ROW acquisition, and permitting efforts,
are not shown in the summary schedule.
32
33
The schedule is predicated upon IPC’s ability to complete the following tasks in a timely
manner:
34
x
Secure all necessary permit approvals;
35
x
Secure agency support;
36
x
Complete biological and cultural survey work;
37
x
Construct within environmental time constraints;
38
x
Order and receive equipment;
39
40
x
Secure construction contractor resources and associated construction equipment;
and
41
42
x
Maintain continuous construction activity with no delay due to environmental,
administrative, or legal issues.
43
November 2011
53
Transmission Line and Substation Components
Appendix B
1
3.0
SYSTEM OPERATIONS AND MAINTENANCE
2
3
4
5
6
The 500-kV transmission lines to be constructed as part of the Project will comprise critical
infrastructure of the IPC transmission systems, and of the western U.S. electrical grid. Limiting
the duration of unplanned outages and planning for the use of live-line maintenance techniques
to minimize the requirement for any outages is an important part of the design, construction, and
operations/maintenance requirements for this Project.
7
3.1 Routine System Operations and Maintenance
8
9
10
11
12
13
IPC’s goal is to provide their customers with a reliable supply of electricity while maintaining the
overall integrity of the regional electrical grid. IPC’s obligation to maintain reliable operation of
the electrical system is documented in IPC’s agreements with the various states through the
public service commissions, and is directed through compliance with industry standard codes
and practices such as the National Electrical Safety Code (ANSI C2), which governs the design
and operation of high-voltage electric utility systems.
14
15
16
17
18
19
20
21
22
23
24
25
In 2005, Congress passed the Energy Policy Act of 2005, which provided a regulatory basis for
the implementation of specific incentives (and penalties) for maintaining reliable service, among
other issues. As a result of the passage of the Act, the FERC selected the NERC to act as the
enforcement agency for compliance with electric utility reliability and operating standards,
among other issues. IPC is required to be in compliance with the various reliability standards
promulgated through the implementation of the NERC policies and procedures. Additionally,
PacifiCorp and IPC are governed by the WECC standards that may be in addition to or more
stringent than those currently required by NERC. In response, IPC has prepared internal
operation and maintenance policies and procedures designed to meet the requirements of the
NERC, WECC, and the state public utility commissions, while remaining in compliance with the
applicable codes and standards with respect to maintaining the reliability of the electrical
system.
26
27
28
29
30
31
32
Operations and maintenance activities will include transmission line patrols, climbing
inspections, tower and wire maintenance, insulator washing in selected areas as needed, and
access roads repairs. IPC will keep necessary work areas around structures clear of vegetation
and will limit the height of vegetation along the ROW. Periodic inspection and maintenance of
each of the substations and communications facilities is also a key part of operating and
maintaining the electrical system. The following sections provide details on the anticipated
operation and maintenance activities for the Project.
33
34
35
36
37
After the transmission line has been energized, land uses that are compatible with safety
regulations will be permitted in and adjacent to the ROW. Existing land uses such as agriculture
and grazing are generally permitted within the ROW. Incompatible land uses within the ROW
include construction and maintenance of inhabited dwellings and any use requiring changes in
surface elevation that will affect electrical clearances of existing or planned facilities.
38
39
40
41
Land uses that comply with local regulations will be permitted adjacent to the ROW. Compatible
uses of the ROW on public lands will have to be approved by the appropriate agency.
Permission to use the ROW on private lands will have to be obtained from the utility owning the
transmission line.
42
3.1.1 Routine System Inspection, Maintenance, and Repair
43
44
Regular inspection of transmission lines, substations, and support systems is critical for safe,
efficient, and economical operation of the Project.
November 2011
54
Transmission Line and Substation Components
Appendix B
1
3.1.2 Transmission Line Maintenance
2
3
4
5
6
Regular ground and aerial inspections will be performed in accordance with the IPC’s
established policies and procedures for transmission line inspection and maintenance. IPC
transmission lines and substations will be inspected for corrosion, equipment misalignment,
loose fittings, vandalism, and other mechanical problems. The need for vegetation management
will also be determined during inspection patrols.
7
8
9
10
11
12
13
14
15
16
Inspection of the entire transmission line system will be conducted semi-annually. Aerial
inspection will be conducted by helicopter semi-annually and will require two or three crew
members, including the pilot. Detailed ground inspections will take place on an annual basis
using service roads to each structure. Ground inspection will use 4x4 trucks or 4x4 ATVs. The
inspector will assess the condition of the transmission line and hardware to determine if any
components need to be repaired or replaced, or if other conditions exist that require
maintenance or modification activities. The inspector will also note any unauthorized
encroachments and trash dumping on the ROW that could constitute a safety hazard. The
inspector will access each of the structure locations along each line and use binoculars and
spotting scopes to perform this inspection.
17
18
19
20
21
22
IPC performs a number of activities to keep its transmission lines operational and in good repair.
These activities can be planned, such as those for routine patrols, inspections, scheduled
maintenance, and scheduled emergency maintenance, or they can be unplanned, such as
those for emergency maintenance in cases where public safety and property are threatened.
For the purpose of this POD, activities are divided into routine, corrective, and emergency
maintenance.
23
24
25
26
27
28
29
30
31
Maintenance activities will be conducted in accordance with this POD and ROW grant
stipulations. Unless specifically noted, IPC will implement the environmental protection
measures described in Section 4 of this POD while conducting routine, corrective, and
emergency maintenance activities. IPC will notify the BLM of proposed activities when
previously identified threatened, endangered, and sensitive (TES) species and cultural
resources occur within, or adjacent to, the work area. IPC also will notify the BLM of emergency
maintenance activities as soon as possible. Routine and corrective maintenance activities that
are not adjacent to TES species or cultural resources will be conducted as necessary and
without prior notification to the BLM.
32
3.1.2.1 Routine Maintenance
Routine maintenance activities are conducted on a regular basis, have been carried out
historically, do not damage vegetation or soil outside of the ROW, and do not adversely impact
sensitive resources—including known TES species, waters of the United States, and cultural
resources. Personnel are generally present in any one area for less than 1 day. The following
are examples of routine maintenance activities.
33
34
35
36
37
38
39
x
Routine air patrols from a helicopter to inspect for structural and conductor defects,
conductor clearance problems, and hazard tree identification.
40
41
42
43
44
45
x
Routine ground patrols to inspect structural and conductor components. Such
inspections may require either an ATV or a pickup truck traveling on access and
service roads and may rely on either direct line-of-sight or binoculars. Patrols are
typically conducted in the spring and fall. Follow-up maintenance is scheduled
depending on the severity of the problem—either as soon as possible or as part of
routine scheduled maintenance.
November 2011
55
Transmission Line and Substation Components
Appendix B
1
2
x
Climbing structures to inspect hardware or make repairs. Personnel access these
structures by pickup truck or ATV or by foot.
3
4
x
Structure or conductor maintenance from a bucket truck. The bucket truck may be
located on or off a road, and no grading is necessary to create a safe work area.
5
6
7
x
Cathodic protection surveys typically require personnel to use an ATV or a pickup
truck and make brief stops to check the integrity and functionality of the anodes and
ground beds.
8
9
10
11
12
x
Routine cyclical vegetation clearing to trim or remove tall shrubs and trees to ensure
adequate ground-to-conductor clearances. Vegetation clearing cycles vary from 3 to
6 years. Personnel access the area by pickup truck or ATV or by foot; use chainsaws
to clear the vegetation; and typically spend less than a half a day in any one specific
area.
13
14
15
16
17
18
19
x
Removal of individual trees or snags (hazard trees) that pose a risk of falling into
conductors or structures and causing outages or fires. Personnel access hazard
trees by ATV or by foot from an access or service road and cut them with a
chainsaw. Any felled trees or snags are left in place as sources of large woody
debris. Felled green trees are limbed to reduce fire hazard. Vegetation management
to remove hazard vegetation is expected to be limited to a few tower spans because
of the lack of tall shrubs or trees within the ROWs.
20
21
22
23
x
Wood pole treatment to retard rotting and structural degradation. Personnel access
structures by pickup truck or ATV or by foot; inspect and test (including the
subsurface) the poles; and then treat them by injecting preservatives into the poles.
Wood pole inspections and treatments occur on a 10-year cycle.
24
25
26
27
28
29
30
31
x
Routine road maintenance, such as grading the road to improve surface condition
and drainage, or removing minor physical barriers such as rocks and debris. All initial
road maintenance is performed by hand crews using ATVs, pickup trucks,
chainsaws, and hand tools. Trees and brush are cut off at grade to minimize damage
to vehicles. Slash, deadfall, and boulders are placed at the edge of the road or down
slope of the road bed, depending on site topography, to serve as a filtering windrow
to minimize erosion and sedimentation. Smaller vegetation (e.g., grasses) is left in
the road bed unless it is too tall and hinders access.
32
33
34
x
Vegetation removal on service roads to allow the necessary clearance for access
and provide for worker safety. Hand crews access the service roads by pickup truck
or ATV and use chainsaws and hand tools to clear the vegetation.
35
36
37
x
Reduction of fuel loads around wood poles in fire-prone areas by 1) removal of
vegetation within a 10-foot radius and treatment with herbicide or 2) application of a
fire retardant coating to the base of wood poles.
38
39
x
Installation of bird protection devices, bird perch discouragers, and relocation or
removal of bird nests.
40
41
42
43
44
45
3.1.2.2 Corrective Maintenance
On a periodic basis, corrective maintenance may result in more extensive vegetation clearing or
earth movement, and typically involve rehabilitation seeding or measures to control noxious
weeds. Personnel are present in any one location or area for a prolonged time, generally more
than 1 day. The following are examples of corrective maintenance.
x
Non-cyclical vegetation clearing to remove saplings or larger trees in the ROW.
November 2011
56
Transmission Line and Substation Components
Appendix B
1
2
x
Structure or conductor maintenance in which earth must be moved, such as the
creation of a landing pad for construction or maintenance equipment.
3
x
Structure (e.g., cross-arm, insulator, pole) replacement.
4
5
6
7
x
Road maintenance involving erosion control, water drainage installation or repair
(such as culverts or rock crossings), road rehabilitation after major disturbances
(such as slumping), or other road maintenance requiring heavy equipment (not
including routine grading).
8
9
x
Follow-up restoration activities, such as seeding, noxious weed control, and erosion
control.
10
11
x
Conductor replacement will require the use of several types of trucks and equipment
and grading to create a safe work area to hang and pull the conductor into place.
12
13
14
15
3.1.2.3 Emergency Situations
Emergency situations are those conditions that may result in eminent or direct threats to public
safety or threaten or impair IPC’s ability to provide power to its customers or the Western grid.
The following examples include, but are not limited to, real and potential emergency situations.
16
x
Failure of conductor splices.
17
x
Lightning strike or wildfire, resulting in burning of wood pole structures.
18
x
Damage to structures from high winds, ice, or other weather-related conditions.
19
x
Line or system outages or fire hazards caused by trees falling into conductors.
20
21
x
Breaking or eminent failure of crossarms or insulators, potentially causing conductor
failures.
22
x
Vandalism to structures or conductors from shooting or other destructive activities.
23
24
25
26
27
28
29
30
31
32
33
34
If an emergency situation arises, IPC may take immediate corrective action to fix the problem,
safeguard human health, and prevent damage to the environment. Actions are frequently the
same as those that occur during routine operation and maintenance activities (e.g., structure
replacement, road repair), but are in response to a threatening situation. IPC will implement
feasible and practicable measures to avoid and minimize impacts during emergency actions and
will notify the BLM of emergency actions as soon as possible. Activities conducted in response
to emergency situations may not adhere to the conditions of this POD. Where appropriate,
especially regarding rehabilitation efforts, IPC will follow the conditions described within this
POD when responding to an emergency. Site rehabilitation (e.g., remedial grading) will be
implemented where necessary and in consultation with the land managing agency or land
owner. Follow-up actions and additional reporting requirements will be coordinated with the BLM
and USFS on a project-specific basis.
35
3.1.3
36
37
38
39
40
41
42
43
44
Routine maintenance activities are ordinary maintenance tasks that have historically been
performed and are regularly carried out on a routine basis. The work performed is typically
repair or replacement of individual components (no new ground disturbance), performed by
relatively small crews using a minimum of equipment, and usually is conducted within a period
from a few hours up to a few days. Work requires access to the damaged portion of the line to
allow for a safe and efficient repair of the facility. Equipment required for this work may include
4-wheel-drive trucks, material (flatbed) trucks, bucket trucks (low reach), boom trucks (high
reach), or man lifts. This work is scheduled and is typically required due to issues found during
inspections. Typical items that may require periodic replacement on transmission line towers
Hardware Maintenance and Repairs
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Transmission Line and Substation Components
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
Appendix B
include insulators, hardware or tower members. It is expected that these replacements will be
required infrequently.
IPC plans to conduct maintenance on the critical 500-kV transmission line system using live line
maintenance techniques. Maintenance on the transmission lines can be completed safely using
live line techniques thereby avoiding an outage to the critical transmission line infrastructure.
High reach bucket trucks along with other equipment are used to conduct these activities. For
the 500-kV lattice tower structures, this requires that adequate space be available at each
structure site so that the high reach bucket truck can be positioned to one side or the other of
the structure and reach up and over the lower phases to access the upper center phase for liveline maintenance procedures. For the H-frame and monopole structures, this requires that
adequate space be available at each structure site so that a bucket truck can be positioned to
access the outside phases. Figure 3-1 depicts the space requirements for live-line maintenance
for the 500-kV lattice structures. The size and location of these required pads near the
structures may vary depending on the side slope and access road at each site. The work areas
and pads will be cleared to the extent needed to safely complete the work. These pads will
remain in place after construction, but will be revegetated after the initial construction is
completed.
18
November 2011
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Transmission Line and Substation Components
Appendix B
1
2
3
Figure 3-1.
November 2011
Live-line Maintenance Space Requirements, Single-Circuit 500-kV
Lattice Tower
59
Transmission Line and Substation Components
Appendix B
1
3.1.4
Access Road and Work Area Repair
2
3
4
5
6
7
ROW repairs include grading or repair of existing maintenance access roads and work areas,
and spot repair of sites subject to flooding or scouring. Required equipment may include a
grader, backhoe, four-wheel-drive pickup truck, and a cat-loader or bulldozer. The cat-loader
has steel tracks whereas the grader, backhoe, and truck typically have rubber tires. Repairs to
the ROW will be scheduled as a result of line inspections, or will occur in response to an
emergency situation.
8
3.1.5 Vegetation Management
9
10
11
12
13
14
15
16
IPC must maintain work areas adjacent to electrical transmission structures and along the ROW
for vehicle and equipment access necessary for operations, maintenance, and repair, including
live-line maintenance activities as described above under Hardware Maintenance and Repairs.
Shrubs and other obstructions will be regularly removed near structures to facilitate inspection
and maintenance of equipment and to ensure system reliability. At a minimum, trees and brush
will be cleared within a 25-foot radius of the base or foundation of all electrical transmission
structures, and to accommodate equipment pads to conduct live line maintenance operations as
noted.
17
18
19
20
21
22
Vegetation management practices along the ROW will be in accordance with the IPC clearing
specifications and vegetation management plans (Idaho Power 2008). The ROWs for the
Project are dominated by agricultural and shrub-steppe vegetation communities except for the 5
miles across the Wallowa-Whitman National Forest. Interference with conductors is not
anticipated. However, if vegetation management is required, IPC will generally schedule it
according to maintenance cycles (e.g., 5- or 10-year cycles).
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
A wire-border zone method is used to control vegetation. This method results in two zones of
clearing and revegetation. The wire zone is the linear area along the ROW under the wires and
extending 10 feet outside of the outermost phase conductor. After initial clearing, vegetation in
the wire zone would be maintained to consist of native grasses, legumes, herbs, ferns, and
other low-growing shrubs that remain under 5 feet tall at maturity. The border zone is the linear
area along each side of the ROW extending from the wire zone to the edge of the ROW.
Vegetation in the border zone would be maintained to consist of tall shrubs or short trees (up to
25 feet high at maturity), grasses, and forbs. These cover plants benefit the ROW by competing
with and excluding undesirable plants. The width of the wire and border zones for the various
transmission lines are depicted in Figure 3-1. During operations, vegetation growth will be
monitored and managed to maintain the wire-border zone objectives. IPC’s approach is to
remove all tree species within the ROW where the conductor ground clearance is less than 50
feet, leaving grasses, legumes, herbs, ferns, and low-growing shrubs within the ROW. When
conductor ground clearance is greater than 50 feet, for example a canyon or ravine crossing
with high ground clearance at mid-span, trees and shrubs will be left in place as long as the
conductor clearance to the vegetation tops is 50 feet or more (see Figure 3-2).
39
November 2011
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Transmission Line and Substation Components
1
2
Appendix B
Single-Circuit 500 kV
3
4
5
Figure 3-2.
Right-of-Way Vegetation Management
6
November 2011
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Transmission Line and Substation Components
Appendix B
1
2
3
4
5
Vegetation will be removed using mechanical equipment such as chain saws, weed trimmers,
rakes, shovels, mowers, and brush hooks. Clearing efforts in heavy growth areas will use
equipment such as a Hydro-Ax or similar. The duration of activities and the size of crew and
equipment required will depend on the amount and size of the vegetation to be trimmed or
removed.
6
7
8
In selected areas, herbicides may be used to control noxious weeds and to meet vegetation
management objectives. All herbicide applications will be performed in accordance with federal,
state, and local regulations, and in compliance with managing land agency requirements.
9
3.1.6 Noxious Weed Control
10
11
12
13
14
15
16
17
18
The States of Idaho and Oregon list modes of action that are capable of disseminating noxious
weeds and the duties to control the spread of listed noxious weeds. Equipment and supplies
necessary for line construction and future operation and maintenance activities, and the
activities themselves, are possible agents for the spread of noxious weeds. Under the
requirements of a ROW grant or SUP, IPC is responsible for control of noxious weed species
that result or will result from the construction, operation, and maintenance of the improvements
authorized under the grant. Therefore, a noxious weed control strategy to reduce the
opportunity for weeds to invade new areas and to minimize the spread of weeds within the
Project area will be addressed in the Framework Reclamation Plan.
19
20
21
22
23
24
25
The responsible party will clean all equipment that may operate off-road or disturb the ground
before beginning construction or operation and maintenance activities within a pre-determined
project area. This process will clean tracks and other parts of the equipment that could trap soil
and debris and will reduce the potential for introduction or spread of undesirable exotic
vegetation. Preferably, the cleaning will occur at an IPC operation center, commercial car wash,
or similar facility. Vehicles traveling only on established paved roads are not required to be
cleaned.
26
3.1.7 Substation and Communication Site Maintenance
27
28
29
30
31
32
33
34
35
36
37
Substation and communication site monitoring and control functions are performed remotely
from IPC’s operation center in Boise, Idaho. Unauthorized entry into substations or
communication sites is prevented with the provision of fencing and locked gates. Warning signs
will be posted and entry to the operating facilities will be restricted to authorized personnel.
Project substations and communication sites will not be staffed; however, a remotely monitored
security system will be installed. Several forms of security are planned for each of the locations,
although the security arrangements at each of the substations or communication sites may differ
somewhat. Security measures may include fire detection in the control building via the remote
monitoring system; alarming for forced entry; and a perimeter security system coupled with
remote sensing infrared camera equipment in the fenced area of the station to provide visual
observation/confirmation to the system operator of disturbances at the fence line.
38
39
40
41
42
43
44
45
46
47
Maintenance activities include equipment testing, equipment monitoring and repair, and
emergency and routine procedures for service continuity and preventive maintenance. It is
anticipated that maintenance at each substation will require approximately six trips per year by a
2- to 4-person crew. Routine operations will require one or two workers in a light utility truck to
visit the substations monthly. Typically, once per year a major maintenance inspection will take
place requiring up to 15 personnel for 1 to 3 weeks. Communication sites will be visited every 2
to 3 months by one individual in a light truck to inspect the facilities. Annual maintenance will be
performed by a two man crew in a light truck over a 2- to 5-day period. If substation landscaping
is required by the permitting agency, drought-tolerant plant materials will be used to minimize
watering requirements after plant establishment.
November 2011
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Transmission Line and Substation Components
Appendix B
1
2
3
4
5
Safety lighting at the substations will be provided inside the substation fence for the purpose of
emergency repair work. Because night activities are not expected to occur more than once per
year, the safety lighting inside the substation fence will normally be turned off. One floodlight,
mounted near the entry gate to safely illuminate the substation entry gate, may be left on during
nighttime hours.
6
3.2 Emergency Response
7
8
9
10
The operation of the system is remotely managed and monitored by IPC from their operation
center in Boise, Idaho. Electrical outages or variations from normal operating protocols will be
sensed and reported at these operation centers. As well, the substations are equipped with
remote monitoring, proximity alarms, and in some cases video surveillance.
11
12
13
Emergency situations are those conditions that may result in eminent or direct threats to public
safety or threaten or impair IPC’s ability to provide power to its customers or the Western grid.
The following examples include, but are not limited to, real and potential emergency situations:
14
x
Failure of conductor splices.
15
x
Lightning strike or wildfire.
16
x
Damage to structures from high winds, ice, or other weather-related conditions.
17
x
Line or system outages or fire hazards caused by trees falling into conductors.
18
19
x
Breaking or eminent failure of crossarms or insulators, which could, or does, cause
conductor failures.
20
x
Vandalism to structures or conductors from shooting or other destructive activities.
21
22
23
24
25
26
The implementation of routine operation and maintenance activities on powerlines will minimize
the need for most emergency repairs. Emergency maintenance activities are often those
activities necessary to repair natural hazard, fire, or human-caused damages to a line. Such
work is required to eliminate a safety hazard, prevent imminent damage to the powerline, or
restore service if there is an outage. In an emergency, IPC must respond as quickly as possible
to restore power.
27
28
29
30
The equipment necessary to carry out emergency repairs is similar to that necessary to conduct
routine maintenance, in most cases. Emergency response to outages may require additional
equipment to complete the repairs. For example, where the site of the outage is remote,
helicopters may be used to respond quickly to emergencies.
31
32
33
In practice, as soon as an incident is detected, the control room dispatchers will notify the
responsible operations staff in the area(s) affected and crews and equipment will be organized
and dispatched to respond to the incident.
34
3.2.1 Fire Protection
35
36
37
All federal, state, and county laws, ordinances, rules, and regulations pertaining to fire
prevention and suppression will be strictly adhered to. All personnel will be advised of their
responsibilities under the applicable fire laws and regulations.
38
39
40
IPC will regularly inspect the transmission line for fire hazards. IPC crews and contractors will
have the following equipment when working in or around the transmission line on BLMmanaged and National Forest lands:
41
42
x
All power-driven equipment, except portable fire pumps, shall be equipped with one
fire extinguisher having a UL rating of at least 5 BC, and one “D” handled or long
November 2011
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Transmission Line and Substation Components
handled round point shovel, size “0” or larger. In addition, each motor patrol, truck
and passenger-carrying vehicle shall be equipped with a double-bit axe or Pulaski,
3½ pounds or larger.
1
2
3
4
5
6
7
Appendix B
x
Each internal combustion engine shall be equipped with a spark arrester meeting
either 1) USDA Forest Service Standard 5100-1a, or 2) appropriate Society of
Automotive Engineers recommended practice J335(b) and J350(a) as now or
hereafter amended unless it is:
8
9
–
Equipped with a turbine-driven exhaust supercharger such as the turbocharger.
There shall be no exhaust bypass.
10
11
12
–
A passenger-carrying vehicle or light truck, or medium truck up to 40,000 GVW,
used on roads and equipped with a factory-designed muffler complete with
baffles and an exhaust system in good working condition.
13
14
15
–
A heavy-duty truck, such as a dump or log truck, or other vehicle used for
commercial hauling, used on roads only and equipped with a factory-designed
muffler and with a vertical stack exhaust system extending above the cab.
16
17
x
Exhaust equipment, including spark arresters and mufflers, shall be properly installed
and constantly maintained in serviceable condition.
18
19
20
21
22
When working on public or National Forest lands, IPC’s employees and contractors will be
equipped with approved suppression tools and equipment. IPC or their construction contractor
will notify local fire authorities and the BLM or Forest Service (as appropriate) if a Project-related
fire occurs within or adjacent to a construction area. Smoking is not allowed outside of vehicles,
cleared storage yards/staging areas, and/or construction trailers.
23
24
25
26
27
28
29
30
31
32
If IPC becomes aware of an emergency situation that is caused by a fire on or threatening BLMmanaged or National Forest lands and that could damage the transmission lines or their
operation, they will notify the appropriate agency contact. Specific construction-related activities
and safety measures will be implemented during construction of the transmission line to prevent
fires and to ensure quick response and suppression if a fire occurs. Typical practices to prevent
fires during construction and maintenance/repair activities include brush clearing prior to work,
stationing a water truck at the job site to keep the ground and vegetation moist in extreme fire
conditions, enforcing red flag warnings, providing “fire behavior” training to all pertinent
personnel, keeping vehicles on or within designated roads or work areas, and providing fire
suppression equipment and emergency notification numbers at each construction site.
November 2011
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Transmission Line and Substation Components
Appendix B
1
4.0
DECOMMISSIONING
2
3
4
5
6
7
8
The proposed transmission line will have a projected operational life of at least 50 years or
longer. At the end of the useful life of the Project and if the facility were no longer required, the
transmission line will be removed from service. At such time, conductors, insulators, and
hardware will be dismantled and removed from the ROW. Structures will be removed and
foundations removed to below ground surface. Decommissioning and restoration on USFS
lands shall be consistent with the terms and conditions of the USFS authorization and shall not
include abandoning foundations or leaving in-place.
9
10
11
12
13
14
15
Following abandonment and removal of the transmission line structures and equipment from the
ROW, any areas disturbed areas during line dismantle will be restored and rehabilitated. If a
substation is no longer required, the substation structures and equipment will be dismantled and
removed from the site. The station structures will be disassembled and either re-used at another
station or sold for scrap. Major equipment such as breakers, transformers, and reactors will be
removed, refurbished, and stored for use at another facility. Foundations will be either
abandoned in-place or cut off below ground level and buried.
16
17
18
19
20
21
22
23
24
25
26
IPC describes roads necessary for the operation and maintenance of transmission lines as
access roads or service roads. The sole purpose of service roads is to provide maintenance
crews access to the transmission lines. These roads will not exist if the transmission lines did
not exist. In contrast, access roads serve a broader purpose, such as contributing to the federal,
county, or state road systems. Access roads provide direct or indirect access to the
transmission lines but that access is not their primary purpose. IPC is responsible for the
reclamation of service roads following abandonment and in accordance with the landowner’s
direction but is not responsible for reclamation of access roads unless mutually agreed upon by
IPC and the landowner. Service roads will be abandoned following removal of the structures
and lines and may be abandoned while the lines are in-service if they are determined to no
longer be necessary.
27
28
29
30
When a service road has been identified as no longer necessary, the road will be reclaimed and
seeded as soon as possible during the optimal seeding season. In some cases, reseeding may
not be necessary, given the existing amount of soil compaction and vegetation currently in
place.
31
32
33
34
35
36
37
38
The seed mix used for any restoration and revegetation project will be determined in
consultation with the landowner or land-managing agency. All seed will meet all of the
requirements of the Federal Seed Act and applicable Idaho and Oregon laws regarding seeds
and noxious weeds. Only seed certified as “noxious weed-free” will be used. If requested, IPC
or their contractor will provide the landowner with evidence of seed certification. Any seed
mixture will not contain aggressive, non-native species that might invade the site. Where
necessary, the surface of the ground will be prepared prior to seeding. Where practical, IPC will
follow these guidelines for preparing the seedbed:
39
40
41
x
The road surface will be cleared of foreign materials, such as garbage, paper, and
other materials, but all rocks, limbs, or minor woody debris will be left in place. IPC or
their contractor will prepare the seedbed immediately prior to seeding.
42
43
44
45
x
Under the right soil-moisture conditions, a standard disk or spring bar harrow will be
used to roughen the topsoil layer to create the desired surface texture before the
seed is applied. Dirt clods and chiseled voids resulting from the roughening process
increase the surface area for water collection and provide micro-sites for seed
November 2011
65
Transmission Line and Substation Components
establishment. The soil should be disked or harrowed to no more than 2 inches deep
at a time when soil moisture allows the surface to remain rough, with clods
approximately 2 to 4 inches in diameter.
1
2
3
4
5
6
Appendix B
x
Disking or harrowing will be performed parallel to surface contours. In this way,
downslope alignment of furrows can be avoided. In areas that already have the
desired soil characteristics; the seedbed does not need to be prepared.
7
8
9
10
11
12
13
After the seedbed has been prepared, IPC or their contractor will broadcast the seed on the
disturbed area, after which the seed will be lightly harrowed into the roadbed or raked into the
ground. Mulch and fertilizers may be added if necessary. An area will not be seeded when wind
velocities prohibit the seed mix from being applied evenly. If the seed does not germinate and
establish to an agreed-upon level of vegetation cover (e.g., consistent with adjacent site
conditions) after two growing seasons, IPC or their contractor will do a one-time reseeding
during a period acceptable to the landowner.
14
15
Other seeding methods, such as drilling, hydroseeding, or aerial application, may be used
depending on the area that requires reclamation and site conditions.
16
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