Corrosion Protection for Pipelines Draft Basis of Design

Corrosion Protection for Pipelines

Draft Basis of Design Report

Sacramento County Regional Sanitation District (Regional San)

HARVEST WATER PROGRAM

Prepared for: Michael Harrison, PE

Engineering Lead, Harvest Water Program C-PMO

Sacramento Regional County Sanitation District

8521 Laguna Station Road

Elk Grove, CA 95758

Prepared by: Ken Kalemkarian, EIT

Chelsea Teall, PE

Reviewed by: Chris Sheldon, PE

Glenn Willson, PE

Date: October 30, 2020

V&A Project No. 19-0093

Harvest Water Program: Corrosion Protection for Pipelines BODR Introduction

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1 Introduction V&A Consulting Engineers, Inc. (V&A) is a corrosion engineering subconsultant to Brown & Caldwell

(B&C) and Carollo on the Capital Program Management Services (C-PMO) team for Sacramento Regional

County Sanitation District’s (Regional San’s) Harvest Water Program. The Harvest Water Program was

developed to meet Regional San’s long-term goals of increasing the production and use of recycled

water. The Harvest Water Program offers multiple benefits, including providing a safe and reliable

supply of tertiary-treated water for agricultural uses, reducing groundwater pumping, supporting habitat

restoration efforts, and providing both near-term and long-term benefits to the Sacramento-San Joaquin

Delta. The facilities to be constructed by this Program will include a recycled water pump station

(approximately 75 MGD at build-out), about 14 miles of transmission pipeline (18- to 66-inch diameter),

25 miles of distribution pipelines and laterals, appurtenant facilities, and potentially a dedicated

recharge basin. The scope of this Basis of Design Report (BODR) includes the transmission and

distribution pipelines, which are shown in Figure 1-1.

The role of the C-PMO is to design and construct facilities that have been planned by the A-PMO, or

Administration Program Management Office. The A-PMO is led by Regional San’s Department of Policy

and Planning. The C-PMO will work closely with the A-PMO to support their continued efforts related to

planning, permitting, end-user coordination, public outreach, etc. The C-PMO will develop a Basis of

Design for the overall system and establish a plan for sequencing the design and construction of the

various system components. The C-PMO will develop and issue separate RFPs for design services for

each of the discrete projects defined by the sequencing plan and will manage those projects throu gh

commissioning.

The first step in designing a corrosion control system is to investigate the soil corrosivity. The methods

used to perform the investigations, detailed results of the investigations, and recommendations for

corrosion control of the proposed pipeline materials shall be summarized in a preliminary design report

for each project. The objectives of the soil corrosivity investigations conducted by each project team

should include the following:

1. Review the results of the in-situ soil resistivity testing performed by the C-PMO, which are

summarized in Section 2 and Appendix A of this BODR

2. Collect and review the results of soil sample resistivity testing

3. Collect and review the results of soil sample chemical analysis

4. Discuss the influence of soil parameters on soil corrosivity towards the proposed pipeline materials

5. Recommend either a cathodic protection (CP) system or corrosion monitoring sys tem for metallic

portions of the pipelines based on the soil corrosivity

A corrosion monitoring system consists of test stations, joint bonds, and insulating joints. A CP system

includes a CP current source in addition to all the elements of a corrosion mo nitoring system. The types

of CP systems are discussed further in Section 3.

One of the primary driving factors for designing the CP system is the current requirement of the p ipeline

to be protected. The current required to protect the pipeline can be determined empirically, if the

pipeline is already installed, or theoretically, if it is not. Since the Harvest Water Program involves

installing new pipelines, the CP current requirement will be estimated using theoretical calculations.

Harvest Water Program: Corrosion Protection for Pipelines BODR Introduction

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Once the current requirement is known, the number and type of anodes, rectifier current and voltage,

and other parameters for the CP system are calculated, as discussed in Section 4. Other variables and

components of the CP system design are discussed in this report as well, such as electrical isolation

from foreign metallic structures (Section 5), joint bonds for providing an electrically continuous pipeline

(Section 6), and test stations (Section 7).

Additionally, foreign utilities could accelerate the corrosion of the pipeline regardless of whether the

pipeline is cathodically protected. There are two types of foreign utilities that are of concern: (1) Buried

pipelines with CP and (2) overhead AC transmission lines. The circumstances under which these foreign

utilities are of concern and mitigating measures are discussed in Section 8.

Figure 1-1. Harvest Water Program Transmission and Distribution Pipeline Alignments

Harvest Water Program: Corrosion Protection for Pipelines BODR Soil Corrosivity

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2 Soil Corrosivity Soil corrosivity can be estimated based on measured soil properties, such as soil resistivity, pH, and

concentrations of water-soluble chloride, sulfate, and bicarbonate ions.

Soil resistivity is a property that quantifies how strongly soil opposes the fl ow of electric current.

Since corrosion is an electrochemical process accompanied by current flow, it is of primary

importance to measure resistivity when investigating soil corrosivity. A lower soil resistivity value

generally corresponds with a greater degree of electrical activity and a higher corrosion rate.

Lower pH (more acidic) soil tends to prevent the formation of protective oxide layers on the surface

of metallic structures. The formation of a protective layer in high pH environments is referred to as

passivation.

Higher concentrations of ions can break down protective oxide films, reduce the quality of concrete

cover, and decrease soil resistivity in wet weather conditions.

▪ In addition to lowering soil resistivity in wet weather conditions, high concentrations of chloride

ions tend to break down otherwise protective surface oxide films and can promote corrosion of

buried metallic structures and reinforcing steel embedded in concrete.

▪ In addition to reducing soil resistivity in wet weather conditions, high concentrations of sulfate

ions can chemically attack concrete structures and promote corrosion of buried metallic

structures.

▪ Although bicarbonates are not directly aggressive to buried metallic or concrete structures,

higher concentrations tend to decrease soil resistivity and promote corrosion activity.

V&A measured in-situ soil resistivity along the transmission and distribution pipeline alignments to

preliminarily assess the soil corrosivity for the Harvest Water Program. The corrosion enginee r for each

project within the program should perform additional measurements on soil samples collected at the

pipeline depths from borings taken by the project geotechnical engineers to further characterize the

soil. The soil samples should be tested in the laboratory for minimum soil resistivity, pH, and

concentrations of water-soluble chloride, sulfate, and bicarbonate ions.

The methods used to perform the in-situ soil resistivity testing, detailed results of the testing, and

corresponding preliminary soil corrosivity are presented in this section. V&A performed the in-situ soil

resistivity testing from September 8th through October 21st, 2020. Testing was performed at 167

locations along the proposed pipeline alignment to depths of 5, 10, 15, and 20 feet. Measurements

were also taken to a depth of 30 feet at locations where the pipeline will cross rivers, railroads, or other

features requiring the pipeline to be buried deeper.

A map showing an overview of the proposed pipeline alignment featuring the in-situ soil resistivity test

locations is shown in Figure 2-1. Note that not all measurement locations are labeled on Figure 2-1;

however, all points are clearly labeled on the more detailed maps in Appendix B.


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Figure 2-1. Project Vicinity Map


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2.1 Methods

Soil resistivity is a property that quantifies how strongly soil opposes the flow of electric current. Since

corrosion is an electrochemical process accompanied by current flow, it is of primary importance to

measure resistivity when investigating soil corrosivity. A lower soil resistivity value generally

corresponds with a greater degree of electrical activity and a higher corrosion rate. The methods used

to measure soil resistivity are discussed in this section.

In-situ Soil Resistivity Testing

In-situ soil resistivity testing was performed using the Wenner 4-Pin Method in accordance with

ASTM G57. This test method involves the use of four metallic pins driven into the soil in a straight line at

equidistant spacing. A ground resistance tester is used to discharge alternating current into the soil

from the two outer pins. The current creates a voltage gradient in the soil proportional to the average

resistance of the soil. The voltage drop between the two inner pins is measured, and the resistance of

the soil to a depth equal to the p in spacing is calculated by the meter using Ohm’s Law (“resistance is

equal to voltage divided by current,” or R = V/I). A typical Wenner 4-pin resistivity test setup is

presented in Figure 2-2, and an example setup is shown in Photo 2-1.

Figure 2-2. Soil Resistivity Measurement Setup

Soil Resistance Meter

C1 P1 P2 C2

1.53 Ω Calculate Resistance

Pin

x x x

Pin Spacing

Test Wire

Measure Voltage (V)

Apply Current (A)


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Photo 2-1. Example of Wenner 4-Pin Test Setup

The soil resistance value from the meter is recorded, and resistivity of the soil to a depth equal to the

pin spacing is calculated with the following formula:

𝜌 = 2𝜋𝑥𝑅

where ρ = soil resistivity (Ω-cm)

π = 3.14 (approximately)

x = distance between pins (cm)

R = soil resistance, value from meter (Ω)

At the completion of each test, the pin spacing is adjusted and the test is repeated.


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Barnes Soil Layer Resistivity Calculations

The soil resistance values from the meter are also used to calculate the resistivity of individual layers of

soil; this procedure is referred to as the Barnes Soil Layer Resistivity Calculations. The relation between

soil resistivity to depth and soil layer resistivity is shown graphically in Figure 2-3.

Figure 2-3. Soil Resistivity to Depth and Soil Layer Resistivity

Individual soil layer resistances (RA-B) are calculated using the following formula:

𝑅𝐴−𝐵 =𝑅𝐴𝑅𝐵𝑅𝐴 − 𝑅𝐵

where RA-B = resistance of soil layer between depth A and depth B (Ω)

RA = soil resistance to depth A, value from meter (Ω)

RB = soil resistance to depth B, value from meter (Ω)

Note that the resistance of the soil layer from grade to 5 feet below grade ( R0-A) is equivalent to

resistance to depth A (RA) and is not calculated using the Barnes Layer formula. Average resistivity of a

layer of soil (ρA-B) is calculated with the following equation:

𝜌𝐴−𝐵 = 2𝜋(𝐵 − 𝐴)𝑅𝐴−𝐵

where ρA-B = average resistivity of soil layer from depth A to depth B (Ω-cm)

π = 3.14 (approximately)

A = depth below grade to top of soil layer (cm)

B = depth below grade to bottom of soil layer (cm)

RA-B = resistance of soil layer between depth A and depth B (Ω)

Layer 0-A (5 feet)

Layer A-B (5 feet)

Layer B-C (5 feet)

Layer C-D (5 feet)

Layer D-E (10 feet)

Soil Layer Resistivity

Depth 0 (0 feet below grade)

Depth A (5 feet below grade)

Depth B (10 feet below grade)

Depth C (15 feet below grade)

Depth D (20 feet below grade)

Depth E (30 feet below grade)

Soil Resistivity to Depth


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Interpretation of Soil Resistivity Data

The correlation between resistivity and anticipated corrosion activity of steel is presented in Table 2-1.

Table 2-1. Effect of Resistivity on Soil Corrosivity1

Soil Resistivity

(Ω-cm) Degree of Corrosivity

≤ 500 Very High

501 – 1,000 High

1,001 – 2,000 Moderate

2,001 – 10,000 Mild

> 10,000 Negligible

The interpretation of this correlation varies somewhat among corrosion engineers; however, Table 2-1 is

a generally accepted guide.

2.2 Results and Conclusions

The results of the soil resistivity measurements indicate that soil resistivity is relatively consistent along

the proposed pipeline alignments. In general, the soil at the program location is in the range of 1,000

to 2,500 Ω-cm.

A summary of the in-situ soil resistivity results is presented in Table 2-2 and Table 2-3. The individual

results for each resistivity test location are presented in Appendix A.

Table 2-2. Summary of In-Situ Soil Resistivity Results

Depth

(ft)

Soil Resistivity to Depth (Ω-cm) Layer

(ft)

Resistivity of Layer (Ω-cm)

Average Minimum Maximum Average Minimum Maximum

5 2,327 613 24,513 0 - 5 2,318 613 24,513

10 1,767 594 8,810 5 - 10 1,703 481 7,762

15 1,718 632 6,923 10 - 15 2,058 477 14,676

20 1,679 651 7,009 15 - 20 2,291 440 32,768

30 1,484 1,034 2,356 20 - 30 958 493 1,856

All

Depths

1,863 594 24,513 All Layers 2,063 440 32,768

1 Peabody, A. and Parker, M. “Corrosion Basics, an Introduction,” Ed. By Brasunas, A. NACE International, p. 191 (1984)


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Table 2-3. Overall Percentage of Soil Layer Corrosivity

Corrosivity

Percent of Measurements (%) per Soil Layer (feet)

All Layers 0 - 5 5 - 10 10 - 15 15 - 20 20 - 30

Very High 1 0 1 1 1 0

High 16 12 20 18 17 6

Moderate 52 50 57 51 51 44

Mild 30 37 23 29 28 50

Negligible 1 1 0 1 2 0

Conclusion: Based on the results of the in-situ soil resistivity testing, the soil at the program location

ranges from negligibly to very highly corrosive with most soils ranging from mildly to highly corrosive.

2.3 Recommendations

The following recommendations are presented based on the results and conclusions of the soil

corrosivity investigation:

1. Collect and provide laboratory analysis of soil samples at the pipeline depth every 5,000 feet for

minimum soil resistivity, pH, and concentrations of chloride, sulfate, and bicarbonate ions. The soil

samples shall be collected by the project geotechnical engineer at the direction of a Corrosion

Engineer. A Corrosion Engineer is a Registered Professional Corrosion Engineer or a NACE CP4 (CP

Specialist) with a Professional Engineering license in a related discipline. The Corrosion Engineer

shall assess the soil corrosivity to buried metallic piping and provide recommendations for

corrosion protection in a report.

2. Preliminary results indicate that it is likely that cathodic protection (CP) systems will be required on

buried metallic piping and fittings. The CP system or corrosion monitoring system shall be designed

by a Corrosion Engineer.

3. When designing the CP systems, run scenarios for high, low, and typical resistivities to ensure the

CP system can protect the pipelines within all these conditions (to a reasonable degree).

4. A Coatings Specialist shall either prepare or review the coating and lining specifications for metallic

pipelines and fittings. A Coatings Specialist is a Registered Professional Corrosion Engineer or a

NACE CIP3 with a Professional Engineering license in a related discipline. The specified coatings

and linings shall be suitable for the application.

Harvest Water Program: Corrosion Protection for Pipelines BODR General Information About CP

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3 General Information About CP

CP is a method of corrosion control that uses an external anode as a current source to impress DC

current through the soil onto a pipeline. CP reverses the flow of corrosion currents that occur when a

pipeline is installed in corrosive soil. The pipeline is made more electronegative with respect to the soil,

and the pipeline becomes the cathode in the corrosion cell. The current flows along the pipeline to the

drain cable to complete the circuit.

The first decision the designer, owner, and operator of the CP system need to make is whether to install

a galvanic anode cathodic protection (GACP) or impressed current cathodic protection (ICCP) system.

There are guidelines for when to use each system type based on soil resistivity and the pipeline current

requirement. In addition, each project has unique requirements to consider.

3.1 GACP System Discussion

Within certain limits, galvanic anodes offer a relatively inexpensive and convenient means of controlling

corrosion. In a GACP system, the anodes are constructed from an active metal, such as magnesium or

zinc. The electric potential available to produce the flow of electric current is limited to the difference in

potential between the galvanic anode and the pipeline. The driving voltage between the anode and the

pipeline results in corrosion of the anode and current flow to the pipeline. The use of galvanic anodes is

usually economical in applications where the pipeline has a lower cathodic protection current

requirement (typically less than 1 A), and the soil resistivity is less than 3,000 ohm-cm.

Galvanic anodes have an insulated copper lead wire connected to the anode at one end. The free end

of the lead wire is terminated in a test station for monitoring. The test station includes a terminal board

with mechanical lugs for terminating the anode lead wires and pipeline drain cable. Installation of a test

station allows the pipeline potential and anode current to be measured and monitored to ensure proper

operation of the system. A schematic showing a GACP system is shown in Figure 3-1.


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Figure 3-1. GACP System Schematic

3.2 ICCP System Discussion

Impressed current CP (ICCP) systems use a power source to impress current from an external anode

through the soil to a pipeline. The impressed current anode is constructed from an inert material, such

as graphite or cast iron. A wire from the negative terminal of the power source is connected to the

pipeline and wires from the positive terminal are connected to anodes. A schematic of an impressed

current CP system with a rectifier and anodes in a deep well (one possible anode configuration) is

shown in Figure 3-2.

Power is typically sourced as alternating current (AC) from the electrical grid that is t hen rectified to

direct current (DC). Existing AC power at structures and transformers are used as much as possible.

When possible, rectifiers will be located along access roads or in other areas that provide convenient

access. Alternate power sources can also be used, such as solar systems with photovoltaic panels,

batteries, and charge controllers.

An advantage of an ICCP system over a GACP system is the ability to adjust the amount of protective

current applied to the pipeline and the capability to protect several miles of pipe from one current

source. ICCP systems are generally applicable to situations where AC power is available, the pipeline

has a higher CP current requirement, or soil resistivity is greater than 3,000 oh m-cm.


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Figure 3-2. Impressed Current CP System Schematic

3.3 CP Criteria

One criterion used to determine whether a steel or ductile iron pipeline is adequately protected from

corrosion is commonly called the “−850 mV criterion,” which comes from NACE SP0169, Section

6.2.1.3:

"A structure-to-electrolyte potential of −850 mV or more negative as measured with respect to a saturated

copper/copper sulfate (CSE) reference electrode. This potential may be either a direct measurement of the

polarized potential or a current-applied potential. Interpretation of a current-applied measurement requires

consideration of the significance of voltage drops in the earth and metallic paths."

The polarized potential is measured when the cathodic protection current is momentarily interrupted,

which is called the “instant off” potential. An alternate criterion for determining whether a steel or

ductile iron pipeline is adequately protected from corrosion is commonly called the “100 mV shift

criterion,” which comes from NACE SP0169, Section 6.2.1.2:

"A minimum of 100 millivolts of cathodic polarization. Either the formation or the decay of polarization must be

measured to satisfy this criterion."

The 100 mV shift criterion is satisfied if the difference between the " instant off" and the "native"

potential is at least 100 mV. A “native” potential is measured before the application of CP current. Once

the CP system is installed, the pipeline and CP system shall be tested to ensure either the −850 mV

criterion or the 100 mV shift criterion per NACE 0169 is satisfied.

Harvest Water Program: Corrosion Protection for Pipelines BODR CP System Design Calculations Approach

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4 CP System Design Calculations Approach

4.1 Theoretical Current Requirement

For new pipelines that have not been installed yet, the current requirement is typically th eoretically

calculated based on the expected pipeline surface area and assumed required current density, which is

dependent upon the pipe material and coating. The theoretical current requirement is calculated using

the following equation:

𝐼𝑆 = 𝜋𝐷𝐿𝐶𝐷𝑆 (1 −𝐶𝐸𝑆100

)

where IS = theoretical current requirement (mA)

D = diameter of piping (ft)

L = length of piping (ft)

CDS = assumed required current density (mA/ft2)

CES = assumed coating efficiency (%)

4.2 Sizing the CP System

When designing a CP system, multiple iterations of calculations must be performed until a design can

be found that has a current capacity that exceeds the current requirement of the pipeline, a voltage

capacity that can discharge the required amount of current, and an anod e life of at least 20 years. An

example of some key equations that are used in the design process are the following.

The required voltage and current output are related to one another along with CP circuit resistance by

Ohm’s Law:

𝑉𝑅 = 𝐼𝐶𝑃𝑅𝐶𝑃

where VR = Required voltage (V)

ICP = CP current output (A)

RCP = CP circuit resistance (Ω)

The CP circuit resistance is the sum of the anode resistance, pipeline resistance, and wire resi stance:

𝑅𝐶𝑃 = 𝑅𝐴 + 𝑅𝑊 + 𝑅𝑆

where RCP = CP circuit current (Ω)

RA = resistance of anodes to remote earth (Ω)

RW = resistance of wires (Ω)

RS = resistance of pipeline to remote earth (Ω)

Harvest Water Program: Corrosion Protection for Pipelines BODR Electrical Isolation

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5 Electrical Isolation Metallic pipelines shall be electrically isolated from existing pipes, vaults, and structures. It is important

to electrically isolate the pipelines from these foreign structures because the foreign structures can

drain the CP current (act like a CP current sink). If the structures drain enough CP current from the

pipeline, then the NACE SP0169 CP protection criteria may no longer be achieved, and the pipeline may

not be adequately protected from corrosion. It is also important to isolate new pipelines from old

pipelines because they may have differences in electrochemical potential resulting in galvanic

corrosion. It is recommendation that electrical isolation be designed and installed in accordance with

NACE SP0286, Electrical Insulation of Cathodically Protected Pipelines.

5.1 Insulating Flange Kit

Insulating flange kits refer to flanged joints with insulating components that prevent current passing

from one side of the joint to the other. Insulating flange kits include a gasket that goes between the

flanges, insulating sleeves that prevent the bolt shaft from contacting the flange holes, and insulating

washers that prevent the bolt head and nuts from directly contacting either flange face. Stainless steel

washers are installed along with the insulating washers to provide added strength and distribute load

across the washer.

After the insulating flange kit is installed, it is recommended that the joint be wrapped in petrolatum

wax tape to inhibit current from flowing through the electrolyte and around the join t. The petrolatum wax

tape has the added benefit of providing barrier protection to the electrically isolated stainless steel

fasteners of the joint.

Quality control and care during installation are paramount when using insulating flange kit s, especially

for pipelines with large diameters (such as greater than 42-inches in diameter). Insulating flange kits

have been used successfully on large diameter pipes, but they require careful attention to be installed

correctly. If they are not installed correctly, then there may be electrical shorts, which are oftentimes

found after the pipe has been backfilled.

5.2 Monolithic Insulating Joint

Monolithic insulating joints are factory assembled insulating joints that arrive to the job site as a single

component. This unique design provides proven long-term isolation properties for the joint and should

be considered for large diameter pipelines (over 48-inches in diameter) that are prone to pipeline

settlement. Monolithic insulating joints are designed so that they are either welded into the field piping

during installation or installed via bolted flanges.

Electrical isolation across a monolithic insulating joint is tested before leaving the factory, reducing the

number of electrical shorts found in the field. Monolithic insulating joints typically cost more than

insulating flange kits and have a longer lead time; however, they can be installed at a lower cost, which

makes both types of insulating joint designs competitive alternatives.

Harvest Water Program: Corrosion Protection for Pipelines BODR Electrical Isolation

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5.3 Isolation at Casings

Dielectric spacers are used to isolate the casing from the carrier pipe. The casing is often uncoated

bare steel with a large surface area, which poses the risk of draining significant CP current if it

becomes shorted to the carrier pipe. Properly installed and sufficient dielectric spacers typically provide

effective separation distance for metallic isolation.

End seals are used at the casing ends to minimize the risk of an electrolytic short between the pipeline

and casing. Filling the annular space with a high-resistivity grout should be considered if the casing is

below the water line to prevent electrolytic shorts due to water intrusion in the annular space.

Harvest Water Program: Corrosion Protection for Pipelines BODR Joint Bonds

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6 Joint Bonds The purpose of joint bonds is to decrease the linear resistance of the pipeline and provide electrical

continuity. A CP system behaves as an electrical circuit; current flows to structures (cathodes) that are

electrically continuous with the anodes. When a pipeline is electrically discontinuous, CP current is

unable to protect the pipeline at locations past the discontinuity because the current has no way of

returning back to the rectifier to complete the CP circuit.

Joint bonds are required for non-welded pipe joints, such as bell-and-spigot, bolted, or mechanically

coupled field joints. Joint bonds should not be installed on insulating joints, which are intention ally

installed to provide electrical isolation at the joint.

Joint bonds typically consist of insulated, stranded, copper wires that are exothermically welded to each

side of the joint. The length, gauge, and number of copper wires at each joint shall be determined by

calculating the acceptable increase in attenuation. Typically, an acceptable amount of increased

attenuation is double the amount of attenuation that would be present for a welded pipeline of the

same dimensions. In practice, this means the electrical resistance at each joint should be less than or

equal to the electrical resistance of one stick of pipe.

Harvest Water Program: Corrosion Protection for Pipelines BODR Test Stations

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7 Test Stations The purpose of providing the pipeline with a CP system is to mitigate the harmful effects of external

corrosion due to the soil corrosivity and extend the useful life of the pipeline. Various types of test

stations are used to monitor the performance of the CP system. The pipe-to-soil potentials of the

pipeline can be measured at all of the following types of test stations, whic h is then compared to NACE

criteria for adequate corrosion control to determine the effectiveness of the CP system .

7.1 Monitoring Test Stations (MTS)

MTS are used to measure pipe-to-soil potentials of the pipeline. Two test leads are attached to the

pipeline and terminated in a test station box. The maximum distance between test stations of any type

shall be 1,000 feet, and MTS shall be placed at appropriate intervals between other test station types

to maintain this requirement.

7.2 Insulating Joint Test Stations (IJTS)

IJTS are installed at insulating joints to measure the effectiveness of the insulating joint and ensure it is

functioning properly. IJTS consist of test leads initiating from both sides of the insulating joint and

terminating in a test station box.

7.3 Casing Test Stations (CTS)

CTS are installed at the ends of casings to measure the effectiveness of the isolation between the

carrier pipe and casing. When casings are used, the casing should be electrically isolated from the

carrier pipe. Test leads from the casing and carrier pipe are terminated in a test station box.

7.4 Foreign Pipeline Test Stations (FPTS)

FPTS may be installed at foreign pipeline crossings to measure the electrical interaction between the

project pipeline and the foreign pipeline. The FPTS consists of project pipeline test leads, foreign

pipeline test leads, and galvanic anode test leads terminated in a test station box. If current is

discharging from the project pipeline to the foreign pipeline, then the galvanic anode test leads can be

connected to the project pipeline at the test station box so current will discharge from the anodes

instead of the project pipeline. A neoprene mat should be installed between the project pipeline and

foreign pipeline to increase resistance and reduce current flow through the soil between the pipelines.

7.5 Anode Test Stations (ATS)

ATS are installed where galvanic anodes are cathodically protecting metallic pipelines or metallic

fittings that are associated with PVC pipelines. Test leads from the pipeline or fitting and galvanic

anodes are terminated in a test station box. The current output and open circuit potential of the

galvanic anodes providing CP current should be measured in addition to the pipe -to-soil potentials.

Harvest Water Program: Corrosion Protection for Pipelines BODR Test Stations

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7.6 Post-mounted vs. Flush-mounted Test Station Box

All test leads are terminated in either a post-mounted or flush-mounted test station box. It is common to

use post-mounted test stations in rural areas and open fields because they are easier to find and spot

from a distance. Flush-mounted test stations are commonly used in urban environments and along the

sides of roads because they do not create obstacles. In areas where flush -mounted test stations could

easily be covered up (with vegetation, for instance), then post -mounted test stations should be used.

Harvest Water Program: Corrosion Protection for Pipelines BODR Stray Current Mitigation

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8 Stray Current Mitigation

8.1 DC Stray Current from Buried Foreign Utilities

Interference occurs when a foreign CP system protecting a foreign pipeline influences the project

pipeline, which is not part of the intended system. The voltage gradient created by the foreign CP anode

bed may cause current to flow onto the project pipeline. This DC stray current returns to the foreign CP

rectifier through the project pipeline, which acts as a low resistance conductor. Current discharge from

the project pipeline may occur where the two pipelines cross or in areas of low resistivity soil. Corrosion

occurs at the point where the current leaves the project pipeline (i.e., current discharges) to return to

the foreign CP rectifier. A schematic of DC stray current influence is shown in Figure 8-1. V&A

recommends installing foreign pipeline test stations (FPTS) at foreign pipeline crossings. Refer to

Section 7.4 for detailed information about the FPTS.

Figure 8-1. DC Stray Current Influence

Most DC stray current problems are generally considered to be a combination of two types of

interference:

1. Anodic interference, which occurs where the project pipeline receives CP current from a foreign

pipeline’s anode bed, and generally occurs where the project pipeline is near the foreign pipeline’s

rectifier. The potential of the project pipeline will be shifted electronegatively in areas of anodic

interference.

2. Cathodic interference, which occurs where the project pipeline is discharging CP current into the

soil to the foreign pipeline, and generally occurs where the project pipeline crosses the foreign

Harvest Water Program: Corrosion Protection for Pipelines BODR Stray Current Mitigation

| Project No. 19-0093 | 20

pipeline. The potential of the project pipeline will be shifted electropositively in areas of cathodic

interference.

8.2 AC Stray Current from Overhead Power Lines

AC stray current effects should be considered when pipelines are installed in close vicinity to overhead

electric transmission facilities. Based on experience, general guidance promotes AC stray current

evaluation when the overhead circuit loading is 69 kV and higher and the buried pipeline is within

2,000 feet of the electric corridor; however, specific conditions can modify this guidance. There are two

primary concerns resulting from AC stray currents:

1. Step touch potentials, which pose a safety hazard to employees working on the pipeline (when

touching valves, test leads, etc.).

▪ Locations with induced voltage of 15 VAC or more are a safety risk. This is commonly referred to

as “step touch potential.” Individuals exposed to pipel ines that may have induced voltages

should safely determine the induced voltage value prior to touching the pipeline or its

components.

2. Pipeline corrosion resulting from induced AC.

▪ AC current density can be calculated when induced AC potential and soil resistivity have been

measured. When AC current density is below 20 A/m2, the risk of pipeline corrosion is minimal.

When AC current density values are above 100 A/m2, pipeline corrosion is likely. Between these

two values, pipeline corrosion risk is indeterminate. It is important to note that AC current

density can be high in locations with very low soil resistivity, and locations with pipeline

corrosion risk can exist with induced AC voltage levels as low as 2 VAC.

▪ Typically, AC related pipeline corrosion risk is higher for pipelines that are well coated (steel

pipelines with dielectric coating) as compared to pipelines with low coating efficiency (mortar

coated pipelines). This is due to AC current discharge from the pipeline that may occur at small ,

focused coating holidays (breaks or damaged coating). This project includes both types of

pipelines.

Induced AC potentials on the pipeline can be measured with a referenc e electrode and a calibrated

multimeter. Typically, maximum induced AC potential on the buried pipeline can be found where the

pipeline deviates from the overhead electric corridor after long lengths of parallel occupancy. The

location of pipeline insulating joints are also areas of concern, and induced AC potential should be

measured on each side of the insulating joint.

The project corrosion engineer should review the plan and profile drawings in addition to google earth

maps to identify locations of AC stray current concern for the pipeline. It is recommended that AC

monitoring test stations be installed at strategic “hot spot” locations where induced AC potential may be

highest. AC monitoring test stations should employ a “dead front” test panel to minimize risk associated

with electrical shock. Induced AC potential can be measured at these test stations after installation to

evaluate the pipeline’s AC corrosion and safety risk. Induced AC potential will vary depending on the

overhead electric transmission circuit loading, which changes within a 24-hour cycle and seasonally.

Following commissioning of the cathodic protection system, testing should be coordinated with the

electric utility provider to capture the maximum induced AC conditions on the pipeline .

AC stray current can be effectively managed with the installation of grounding systems an d solid state

decouplers. These devices allow AC stray current to safely drain from the pipeline while maintaining DC

cathodic protection current. Should AC stray current mitigation be required, decoupler sizing and

grounding system design should be completed by a registered Corrosion Engineer or an experienced

NACE-certified Corrosion Specialist (CP4) after cooperative testing with the electric utility provider.

Harvest Water Program: Corrosion Protection for Pipelines BODR Appendix A

In-situ Soil Resistivity Data

| Project No. 19-0093 | A-1

Appendix A In-situ Soil Resistivity Data The following data was collected and analyzed by V&A.

Site

Number

Depth

(feet)

Resistance

to Depth

(ohm)

Resistivity

to Depth

(ohm-cm)

Layer

(feet)

Resistance

of Soil Layer

(ohm)

Resistivity

of Soil Layer

(ohm-cm)

Degree of

Corrosivity for

Layer

1 5 1.00 958 0 - 5 1.00 958 High

10 0.51 977 5 - 10 1.04 997 High

15 0.36 1,034 10 - 15 1.22 1,172 Moderate

20 0.28 1,072 15 - 20 1.26 1,207 Moderate

2 5 1.64 1,570 0 - 5 1.64 1,570 Moderate

10 0.62 1,187 5 - 10 1.00 955 High

15 0.43 1,235 10 - 15 1.40 1,344 Moderate

20 0.32 1,226 15 - 20 1.25 1,198 Moderate

3 5 2.11 2,020 0 - 5 2.11 2,020 Mild

10 0.93 1,781 5 - 10 1.66 1,592 Moderate

15 0.51 1,465 10 - 15 1.13 1,081 Moderate

20 0.36 1,379 15 - 20 1.22 1,172 Moderate

4 5 1.23 1,178 0 - 5 1.23 1,178 Moderate

10 0.54 1,034 5 - 10 0.96 922 High

15 0.41 1,178 10 - 15 1.70 1,631 Moderate

20 0.32 1,226 15 - 20 1.46 1,396 Moderate

5 5 0.86 823 0 - 5 0.86 823 High

10 0.39 747 5 - 10 0.71 683 High

15 0.30 862 10 - 15 1.30 1,245 Moderate

20 0.26 996 15 - 20 1.95 1,867 Moderate

30 0.22 1,264 20 - 30 1.43 2,739 Mild

6 5 1.53 1,465 0 - 5 1.53 1,465 Moderate

10 0.82 1,570 5 - 10 1.77 1,692 Moderate

15 0.62 1,781 10 - 15 2.54 2,434 Mild

20 0.46 1,762 15 - 20 1.78 1,707 Moderate

30 0.32 1,839 20 - 30 1.05 2,014 Mild



| Project No. 19-0093 | A-2

Site

Number

Depth

(feet)

Resistance

to Depth

(ohm)

Resistivity

to Depth

(ohm-cm)

Layer

(feet)

Resistance

of Soil Layer

(ohm)

Resistivity

of Soil Layer

(ohm-cm)

Degree of

Corrosivity for

Layer

7 5 0.64 613 0 - 5 0.64 613 High

10 0.34 651 5 - 10 0.73 695 High

15 0.26 747 10 - 15 1.11 1,058 Moderate

20 0.22 843 15 - 20 1.43 1,369 Moderate

8 5 1.08 1,034 0 - 5 1.08 1,034 Moderate

10 0.71 1,360 5 - 10 2.07 1,984 Moderate

15 0.55 1,580 10 - 15 2.44 2,337 Mild

20 0.46 1,762 15 - 20 2.81 2,692 Mild

9 5 2.61 2,499 0 - 5 2.61 2,499 Mild

10 0.59 1,130 5 - 10 0.76 730 High

15 0.27 776 10 - 15 0.50 477 Very High

20 0.17 651 15 - 20 0.46 440 Very High

10 5 1.91 1,829 0 - 5 1.91 1,829 Moderate

10 0.84 1,609 5 - 10 1.50 1,436 Moderate

15 0.49 1,408 10 - 15 1.18 1,126 Moderate

20 0.33 1,264 15 - 20 1.01 968 High

11 5 2.62 2,509 0 - 5 2.62 2,509 Mild

10 1.22 2,336 5 - 10 2.28 2,186 Mild

15 0.68 1,953 10 - 15 1.54 1,471 Moderate

20 0.46 1,762 15 - 20 1.42 1,361 Moderate

12 5 1.18 1,130 0 - 5 1.18 1,130 Moderate

10 0.63 1,207 5 - 10 1.35 1,294 Moderate

15 0.44 1,264 10 - 15 1.46 1,397 Moderate

20 0.33 1,264 15 - 20 1.32 1,264 Moderate

13 5 4.67 4,472 0 - 5 4.67 4,472 Mild

10 1.47 2,815 5 - 10 2.15 2,054 Mild

15 0.65 1,867 10 - 15 1.17 1,116 Moderate

20 0.44 1,685 15 - 20 1.36 1,304 Moderate

30 0.27 1,551 20 - 30 0.70 1,338 Moderate

14 5 0.94 900 0 - 5 0.94 900 High

10 0.61 1,168 5 - 10 1.74 1,664 Moderate

15 0.45 1,293 10 - 15 1.72 1,643 Moderate

20 0.35 1,341 15 - 20 1.58 1,508 Moderate



| Project No. 19-0093 | A-3

Site

Number

Depth

(feet)

Resistance

to Depth

(ohm)

Resistivity

to Depth

(ohm-cm)

Layer

(feet)

Resistance

of Soil Layer

(ohm)

Resistivity

of Soil Layer

(ohm-cm)

Degree of

Corrosivity for

Layer

15 5 1.01 967 0 - 5 1.01 967 High

10 0.61 1,168 5 - 10 1.54 1,475 Moderate

15 0.44 1,264 10 - 15 1.58 1,512 Moderate

20 0.32 1,226 15 - 20 1.17 1,124 Moderate

16 5 3.21 3,074 0 - 5 3.21 3,074 Mild

10 1.10 2,107 5 - 10 1.67 1,602 Moderate

15 0.48 1,379 10 - 15 0.85 815 High

20 0.36 1,379 15 - 20 1.44 1,379 Moderate

30 0.23 1,321 20 - 30 0.64 1,220 Moderate

17 5 4.21 4,031 0 - 5 4.21 4,031 Mild

10 1.75 3,351 5 - 10 2.99 2,868 Mild

15 0.99 2,844 10 - 15 2.28 2,183 Mild

20 0.65 2,490 15 - 20 1.89 1,812 Moderate

18 5 1.74 1,666 0 - 5 1.74 1,666 Moderate

10 0.71 1,360 5 - 10 1.20 1,149 Moderate

15 0.46 1,321 10 - 15 1.31 1,251 Moderate

20 0.32 1,226 15 - 20 1.05 1,007 Moderate

30 0.25 1,436 20 - 30 1.14 2,189 Mild

19 5 2.01 1,925 0 - 5 2.01 1,925 Moderate

10 0.67 1,283 5 - 10 1.01 962 High

15 0.36 1,034 10 - 15 0.78 745 High

20 0.25 958 15 - 20 0.82 783 High

30 0.18 1,034 20 - 30 0.64 1,231 Moderate

20 5 4.29 4,108 0 - 5 4.29 4,108 Mild

10 1.32 2,528 5 - 10 1.91 1,826 Moderate

15 0.59 1,695 10 - 15 1.07 1,022 Moderate

20 0.37 1,417 15 - 20 0.99 950 High

21 5 1.77 1,695 0 - 5 1.77 1,695 Moderate

10 0.73 1,398 5 - 10 1.24 1,190 Moderate

15 0.46 1,321 10 - 15 1.24 1,191 Moderate

20 0.33 1,264 15 - 20 1.17 1,118 Moderate

22 5 1.61 1,542 0 - 5 1.61 1,542 Moderate

10 0.78 1,494 5 - 10 1.51 1,449 Moderate

15 0.49 1,408 10 - 15 1.32 1,262 Moderate

20 0.38 1,455 15 - 20 1.69 1,621 Moderate



| Project No. 19-0093 | A-4

Site

Number

Depth

(feet)

Resistance

to Depth

(ohm)

Resistivity

to Depth

(ohm-cm)

Layer

(feet)

Resistance

of Soil Layer

(ohm)

Resistivity

of Soil Layer

(ohm-cm)

Degree of

Corrosivity for

Layer

24 5 2.00 1,915 0 - 5 2.00 1,915 Moderate

10 0.66 1,264 5 - 10 0.99 943 High

15 0.37 1,063 10 - 15 0.84 806 High

20 0.28 1,072 15 - 20 1.15 1,102 Moderate

30 0.21 1,207 20 - 30 0.84 1,609 Moderate

25 5 1.65 1,580 0 - 5 1.65 1,580 Moderate

10 0.73 1,398 5 - 10 1.31 1,254 Moderate

15 0.43 1,235 10 - 15 1.05 1,002 Moderate

20 0.30 1,149 15 - 20 0.99 950 High

26 5 1.41 1,350 0 - 5 1.41 1,350 Moderate

10 0.95 1,819 5 - 10 2.91 2,788 Mild

15 0.62 1,781 10 - 15 1.78 1,709 Moderate

20 0.44 1,685 15 - 20 1.52 1,451 Moderate

30 0.32 1,839 20 - 30 1.17 2,247 Mild

27 5 1.46 1,398 0 - 5 1.46 1,398 Moderate

10 0.93 1,781 5 - 10 2.56 2,453 Mild

15 0.58 1,666 10 - 15 1.54 1,476 Moderate

20 0.59 2,260 15 - 20 * * *

28 5 1.14 1,092 0 - 5 1.14 1,092 Moderate

10 0.63 1,207 5 - 10 1.41 1,348 Moderate

15 0.36 1,034 10 - 15 0.84 804 High

20 0.29 1,111 15 - 20 1.49 1,428 Moderate

30 0.22 1,264 20 - 30 0.91 1,745 Moderate

29 5 1.12 1,072 0 - 5 1.12 1,072 Moderate

10 0.73 1,398 5 - 10 2.10 2,007 Mild

15 0.48 1,379 10 - 15 1.40 1,342 Moderate

20 0.37 1,417 15 - 20 1.61 1,546 Moderate

30 0.28 1,609 20 - 30 1.15 2,205 Mild

30 5 0.72 689 0 - 5 0.72 689 High

10 0.40 766 5 - 10 0.90 862 High

15 0.27 776 10 - 15 0.83 796 High

20 0.24 919 15 - 20 2.16 2,068 Mild



| Project No. 19-0093 | A-5

Site

Number

Depth

(feet)

Resistance

to Depth

(ohm)

Resistivity

to Depth

(ohm-cm)

Layer

(feet)

Resistance

of Soil Layer

(ohm)

Resistivity

of Soil Layer

(ohm-cm)

Degree of

Corrosivity for

Layer

31 5 1.98 1,896 0 - 5 1.98 1,896 Moderate

10 1.05 2,011 5 - 10 2.24 2,141 Mild

15 0.63 1,810 10 - 15 1.58 1,508 Moderate

20 0.45 1,724 15 - 20 1.58 1,508 Moderate

30 0.24 1,379 20 - 30 0.51 985 High

32 5 0.95 910 0 - 5 0.95 910 High

10 0.65 1,245 5 - 10 2.06 1,971 Moderate

15 0.51 1,465 10 - 15 2.37 2,267 Mild

20 0.42 1,609 15 - 20 2.38 2,279 Mild

33 5 1.39 1,331 0 - 5 1.39 1,331 Moderate

10 0.69 1,321 5 - 10 1.37 1,312 Moderate

15 0.46 1,321 10 - 15 1.38 1,321 Moderate

20 0.33 1,264 15 - 20 1.17 1,118 Moderate

34 5 1.43 1,369 0 - 5 1.43 1,369 Moderate

10 0.57 1,092 5 - 10 0.95 908 High

15 0.47 1,350 10 - 15 2.68 2,565 Mild

20 0.30 1,149 15 - 20 0.83 794 High

35 5 1.41 1,350 0 - 5 1.41 1,350 Moderate

10 0.60 1,149 5 - 10 1.04 1,000 Moderate

15 0.38 1,092 10 - 15 1.04 992 High

20 0.29 1,111 15 - 20 1.22 1,172 Moderate

30 0.22 1,264 20 - 30 0.91 1,745 Moderate

36 5 2.28 2,183 0 - 5 2.28 2,183 Mild

10 0.95 1,819 5 - 10 1.63 1,559 Moderate

15 0.55 1,580 10 - 15 1.31 1,251 Moderate

20 0.36 1,379 15 - 20 1.04 998 High

37 5 1.25 1,197 0 - 5 1.25 1,197 Moderate

10 0.67 1,283 5 - 10 1.44 1,383 Moderate

15 0.45 1,293 10 - 15 1.37 1,312 Moderate

20 0.34 1,302 15 - 20 1.39 1,332 Moderate

38 5 0.82 785 0 - 5 0.82 785 High

10 0.47 900 5 - 10 1.10 1,054 Moderate

15 0.34 977 10 - 15 1.23 1,177 Moderate

20 0.28 1,072 15 - 20 1.59 1,519 Moderate



| Project No. 19-0093 | A-6

Site

Number

Depth

(feet)

Resistance

to Depth

(ohm)

Resistivity

to Depth

(ohm-cm)

Layer

(feet)

Resistance

of Soil Layer

(ohm)

Resistivity

of Soil Layer

(ohm-cm)

Degree of

Corrosivity for

Layer

39 5 1.72 1,647 0 - 5 1.72 1,647 Moderate

10 0.66 1,264 5 - 10 1.07 1,025 Moderate

15 0.37 1,063 10 - 15 0.84 806 High

20 0.29 1,111 15 - 20 1.34 1,284 Moderate

30 0.23 1,321 20 - 30 1.11 2,129 Mild

40 5 1.58 1,513 0 - 5 1.58 1,513 Moderate

10 0.93 1,781 5 - 10 2.26 2,165 Mild

15 0.78 2,241 10 - 15 4.84 4,631 Mild

20 0.29 1,111 15 - 20 0.46 442 Very High

30 0.23 1,321 20 - 30 1.11 2,129 Mild

41 5 1.10 1,053 0 - 5 1.10 1,053 Moderate

10 0.58 1,111 5 - 10 1.23 1,175 Moderate

15 0.38 1,092 10 - 15 1.10 1,055 Moderate

20 0.29 1,111 15 - 20 1.22 1,172 Moderate

42 5 1.45 1,388 0 - 5 1.45 1,388 Moderate

10 0.99 1,896 5 - 10 3.12 2,988 Mild

15 0.82 2,356 10 - 15 4.78 4,573 Mild

20 0.71 2,719 15 - 20 5.29 5,068 Mild

43 5 0.98 938 0 - 5 0.98 938 High

10 0.57 1,092 5 - 10 1.36 1,305 Moderate

15 0.43 1,235 10 - 15 1.75 1,676 Moderate

20 0.37 1,417 15 - 20 2.65 2,539 Mild

44 5 1.94 1,858 0 - 5 1.94 1,858 Moderate

10 0.73 1,398 5 - 10 1.17 1,121 Moderate

15 0.49 1,408 10 - 15 1.49 1,427 Moderate

20 0.37 1,417 15 - 20 1.51 1,447 Moderate

45 5 1.85 1,771 0 - 5 1.85 1,771 Moderate

10 0.94 1,800 5 - 10 1.91 1,830 Moderate

15 0.49 1,408 10 - 15 1.02 980 High

20 0.30 1,149 15 - 20 0.77 741 High

46 5 2.18 2,087 0 - 5 2.18 2,087 Mild

10 0.79 1,513 5 - 10 1.24 1,186 Moderate

15 0.43 1,235 10 - 15 0.94 904 High

20 0.39 1,494 15 - 20 4.19 4,015 Mild



| Project No. 19-0093 | A-7

Site

Number

Depth

(feet)

Resistance

to Depth

(ohm)

Resistivity

to Depth

(ohm-cm)

Layer

(feet)

Resistance

of Soil Layer

(ohm)

Resistivity

of Soil Layer

(ohm-cm)

Degree of

Corrosivity for

Layer

47 5 1.97 1,886 0 - 5 1.97 1,886 Moderate

10 0.86 1,647 5 - 10 1.53 1,462 Moderate

15 0.58 1,666 10 - 15 1.78 1,706 Moderate

20 0.48 1,839 15 - 20 2.78 2,666 Mild

48 5 3.20 3,064 0 - 5 3.20 3,064 Mild

10 1.06 2,030 5 - 10 1.59 1,518 Moderate

15 0.75 2,155 10 - 15 2.56 2,456 Mild

20 0.65 2,490 15 - 20 4.88 4,668 Mild

49 5 1.45 1,388 0 - 5 1.45 1,388 Moderate

10 0.59 1,130 5 - 10 0.99 953 High

15 0.40 1,149 10 - 15 1.24 1,189 Moderate

20 0.23 881 15 - 20 0.54 518 High

50 5 1.31 1,254 0 - 5 1.31 1,254 Moderate

10 0.75 1,436 5 - 10 1.75 1,680 Moderate

15 0.50 1,436 10 - 15 1.50 1,436 Moderate

20 0.37 1,417 15 - 20 1.42 1,363 Moderate

51 5 6.10 5,841 0 - 5 6.10 5,841 Mild

10 1.90 3,639 5 - 10 2.76 2,642 Mild

15 0.95 2,729 10 - 15 1.90 1,819 Moderate

20 0.58 2,222 15 - 20 1.49 1,426 Moderate

52 5 2.36 2,260 0 - 5 2.36 2,260 Mild

10 0.55 1,053 5 - 10 0.72 687 High

15 0.34 977 10 - 15 0.89 853 High

20 0.27 1,034 15 - 20 1.31 1,256 Moderate

53 5 3.41 3,265 0 - 5 3.41 3,265 Mild

10 0.94 1,800 5 - 10 1.30 1,243 Moderate

15 0.74 2,126 10 - 15 3.48 3,330 Mild

20 0.44 1,685 15 - 20 1.09 1,039 Moderate

54 5 2.12 2,030 0 - 5 2.12 2,030 Mild

10 0.83 1,590 5 - 10 1.36 1,306 Moderate

15 0.43 1,235 10 - 15 0.89 854 High

20 0.31 1,187 15 - 20 1.11 1,064 Moderate

56 5 2.63 2,518 0 - 5 2.63 2,518 Mild

10 1.46 2,796 5 - 10 3.28 3,143 Mild

15 0.84 2,413 10 - 15 1.98 1,894 Moderate

20 0.57 2,183 15 - 20 1.77 1,698 Moderate



| Project No. 19-0093 | A-8

Site

Number

Depth

(feet)

Resistance

to Depth

(ohm)

Resistivity

to Depth

(ohm-cm)

Layer

(feet)

Resistance

of Soil Layer

(ohm)

Resistivity

of Soil Layer

(ohm-cm)

Degree of

Corrosivity for

Layer

57 5 2.37 2,269 0 - 5 2.37 2,269 Mild

10 1.00 1,915 5 - 10 1.73 1,657 Moderate

15 0.82 2,356 10 - 15 4.56 4,362 Mild

20 0.67 2,566 15 - 20 3.66 3,507 Mild

58 5 25.60 24,513 0 - 5 25.60 24,513 Negligible

10 2.19 4,194 5 - 10 2.39 2,293 Mild

15 1.59 4,568 10 - 15 5.80 5,557 Mild

20 0.69 2,643 15 - 20 1.22 1,167 Moderate

59 5 1.75 1,676 0 - 5 1.75 1,676 Moderate

10 0.65 1,245 5 - 10 1.03 990 High

15 0.39 1,120 10 - 15 0.98 934 High

20 0.27 1,034 15 - 20 0.88 840 High

60 5 0.81 776 0 - 5 0.81 776 High

10 0.31 594 5 - 10 0.50 481 Very High

15 0.22 632 10 - 15 0.76 726 High

20 0.18 689 15 - 20 0.99 948 High

61 5 1.43 1,369 0 - 5 1.43 1,369 Moderate

10 0.53 1,015 5 - 10 0.84 806 High

15 0.34 977 10 - 15 0.95 908 High

20 0.25 958 15 - 20 0.94 904 High

62 5 1.75 1,676 0 - 5 1.75 1,676 Moderate

10 0.86 1,647 5 - 10 1.69 1,619 Moderate

15 0.56 1,609 10 - 15 1.61 1,537 Moderate

20 0.43 1,647 15 - 20 1.85 1,774 Moderate

63 5 1.67 1,599 0 - 5 1.67 1,599 Moderate

10 0.69 1,321 5 - 10 1.18 1,126 Moderate

15 0.55 1,580 10 - 15 2.71 2,596 Mild

20 0.45 1,724 15 - 20 2.48 2,370 Mild

64 5 14.30 13,693 0 - 5 14.30 13,693 Negligible

10 4.60 8,810 5 - 10 6.78 6,494 Mild

15 2.41 6,923 10 - 15 5.06 4,847 Mild

20 1.32 5,056 15 - 20 2.92 2,795 Mild

65 5 2.22 2,126 0 - 5 2.22 2,126 Mild

10 1.17 2,241 5 - 10 2.47 2,369 Mild

15 0.80 2,298 10 - 15 2.53 2,422 Mild

20 0.55 2,107 15 - 20 1.76 1,685 Moderate



| Project No. 19-0093 | A-9

Site

Number

Depth

(feet)

Resistance

to Depth

(ohm)

Resistivity

to Depth

(ohm-cm)

Layer

(feet)

Resistance

of Soil Layer

(ohm)

Resistivity

of Soil Layer

(ohm-cm)

Degree of

Corrosivity for

Layer

66 5 2.76 2,643 0 - 5 2.76 2,643 Mild

10 1.29 2,470 5 - 10 2.42 2,319 Mild

15 1.03 2,959 10 - 15 5.11 4,893 Mild

20 0.84 3,217 15 - 20 4.55 4,360 Mild

67 5 1.50 1,436 0 - 5 1.50 1,436 Moderate

10 0.74 1,417 5 - 10 1.46 1,399 Moderate

15 0.48 1,379 10 - 15 1.37 1,308 Moderate

20 0.37 1,417 15 - 20 1.61 1,546 Moderate

68 5 4.00 3,830 0 - 5 4.00 3,830 Mild

10 1.14 2,183 5 - 10 1.59 1,527 Moderate

15 0.56 1,609 10 - 15 1.10 1,054 Moderate

20 0.46 1,762 15 - 20 2.58 2,467 Mild

69 5 1.95 1,867 0 - 5 1.95 1,867 Moderate

10 0.74 1,417 5 - 10 1.19 1,142 Moderate

15 0.44 1,264 10 - 15 1.09 1,039 Moderate

20 0.32 1,226 15 - 20 1.17 1,124 Moderate

70 5 1.28 1,226 0 - 5 1.28 1,226 Moderate

10 0.67 1,283 5 - 10 1.41 1,346 Moderate

15 0.53 1,523 10 - 15 2.54 2,429 Mild

20 0.42 1,609 15 - 20 2.02 1,938 Moderate

71 5 1.55 1,484 0 - 5 1.55 1,484 Moderate

10 0.68 1,302 5 - 10 1.21 1,160 Moderate

15 0.41 1,178 10 - 15 1.03 989 High

20 0.28 1,072 15 - 20 0.88 846 High

72 5 1.87 1,791 0 - 5 1.87 1,791 Moderate

10 0.58 1,111 5 - 10 0.84 805 High

15 0.34 977 10 - 15 0.82 787 High

20 0.26 996 15 - 20 1.11 1,058 Moderate

73 5 3.44 3,294 0 - 5 3.44 3,294 Mild

10 0.89 1,704 5 - 10 1.20 1,150 Moderate

15 0.51 1,465 10 - 15 1.19 1,144 Moderate

20 0.36 1,379 15 - 20 1.22 1,172 Moderate

74 5 0.81 776 0 - 5 0.81 776 High

10 0.39 747 5 - 10 0.75 720 High

15 0.30 862 10 - 15 1.30 1,245 Moderate

20 0.25 958 15 - 20 1.50 1,436 Moderate



| Project No. 19-0093 | A-10

Site

Number

Depth

(feet)

Resistance

to Depth

(ohm)

Resistivity

to Depth

(ohm-cm)

Layer

(feet)

Resistance

of Soil Layer

(ohm)

Resistivity

of Soil Layer

(ohm-cm)

Degree of

Corrosivity for

Layer

75 5 1.42 1,360 0 - 5 1.42 1,360 Moderate

10 0.59 1,130 5 - 10 1.01 967 High

15 0.42 1,207 10 - 15 1.46 1,396 Moderate

20 0.35 1,341 15 - 20 2.10 2,011 Mild

76 5 1.65 1,580 0 - 5 1.65 1,580 Moderate

10 0.84 1,609 5 - 10 1.71 1,638 Moderate

15 0.54 1,551 10 - 15 1.51 1,448 Moderate

20 0.46 1,762 15 - 20 3.11 2,973 Mild

77 5 2.75 2,633 0 - 5 2.75 2,633 Mild

10 1.11 2,126 5 - 10 1.86 1,782 Moderate

15 0.78 2,241 10 - 15 2.62 2,512 Mild

20 0.55 2,107 15 - 20 1.87 1,786 Moderate

78 5 1.01 967 0 - 5 1.01 967 High

10 0.61 1,168 5 - 10 1.54 1,475 Moderate

15 0.42 1,207 10 - 15 1.35 1,291 Moderate

20 0.34 1,302 15 - 20 1.79 1,709 Moderate

79 5 1.01 967 0 - 5 1.01 967 High

10 0.47 900 5 - 10 0.88 842 High

15 0.36 1,034 10 - 15 1.54 1,473 Moderate

20 0.33 1,264 15 - 20 3.96 3,792 Mild

80 5 1.92 1,839 0 - 5 1.92 1,839 Moderate

10 0.63 1,207 5 - 10 0.94 898 High

15 0.52 1,494 10 - 15 2.98 2,852 Mild

20 0.44 1,685 15 - 20 2.86 2,739 Mild

30 0.30 1,724 20 - 30 0.94 1,806 Moderate

81 5 2.72 2,605 0 - 5 2.72 2,605 Mild

10 0.64 1,226 5 - 10 0.84 801 High

15 0.45 1,293 10 - 15 1.52 1,451 Moderate

20 0.29 1,111 15 - 20 0.82 781 High

82 5 2.55 2,442 0 - 5 2.55 2,442 Mild

10 0.92 1,762 5 - 10 1.44 1,378 Moderate

15 0.58 1,666 10 - 15 1.57 1,503 Moderate

20 0.40 1,532 15 - 20 1.29 1,234 Moderate



| Project No. 19-0093 | A-11

Site

Number

Depth

(feet)

Resistance

to Depth

(ohm)

Resistivity

to Depth

(ohm-cm)

Layer

(feet)

Resistance

of Soil Layer

(ohm)

Resistivity

of Soil Layer

(ohm-cm)

Degree of

Corrosivity for

Layer

84 5 2.51 2,403 0 - 5 2.51 2,403 Mild

10 1.40 2,681 5 - 10 3.17 3,031 Mild

15 0.80 2,298 10 - 15 1.87 1,787 Moderate

20 0.52 1,992 15 - 20 1.49 1,423 Moderate

85 5 1.03 986 0 - 5 1.03 986 High

10 0.56 1,072 5 - 10 1.23 1,175 Moderate

15 0.47 1,350 10 - 15 2.92 2,800 Mild

20 0.38 1,455 15 - 20 1.98 1,900 Moderate

86 5 10.37 9,930 0 - 5 10.37 9,930 Mild

10 3.69 7,067 5 - 10 5.73 5,485 Mild

15 1.91 5,487 10 - 15 3.96 3,791 Mild

20 1.35 5,171 15 - 20 4.60 4,409 Mild

87 5 1.40 1,341 0 - 5 1.40 1,341 Moderate

10 0.69 1,321 5 - 10 1.36 1,303 Moderate

15 0.47 1,350 10 - 15 1.47 1,412 Moderate

20 0.35 1,341 15 - 20 1.37 1,313 Moderate

88 5 1.39 1,331 0 - 5 1.39 1,331 Moderate

10 0.81 1,551 5 - 10 1.94 1,859 Moderate

15 0.63 1,810 10 - 15 2.84 2,715 Mild

20 0.46 1,762 15 - 20 1.70 1,632 Moderate

89 5 0.91 871 0 - 5 0.91 871 High

10 0.59 1,130 5 - 10 1.68 1,607 Moderate

15 0.46 1,321 10 - 15 2.09 1,999 Moderate

20 0.37 1,417 15 - 20 1.89 1,811 Moderate

90 5 1.84 1,762 0 - 5 1.84 1,762 Moderate

10 1.27 2,432 5 - 10 4.10 3,926 Mild

15 0.87 2,499 10 - 15 2.76 2,645 Mild

20 0.69 2,643 15 - 20 3.34 3,193 Mild

91 5 8.99 8,608 0 - 5 8.99 8,608 Mild

10 0.70 1,341 5 - 10 0.76 727 High

15 0.52 1,494 10 - 15 2.02 1,936 Moderate

20 0.43 1,647 15 - 20 2.48 2,379 Mild

92 5 2.12 2,030 0 - 5 2.12 2,030 Mild

10 1.04 1,992 5 - 10 2.04 1,955 Moderate

15 0.70 2,011 10 - 15 2.14 2,050 Mild

20 0.53 2,030 15 - 20 2.18 2,090 Mild



| Project No. 19-0093 | A-12

Site

Number

Depth

(feet)

Resistance

to Depth

(ohm)

Resistivity

to Depth

(ohm-cm)

Layer

(feet)

Resistance

of Soil Layer

(ohm)

Resistivity

of Soil Layer

(ohm-cm)

Degree of

Corrosivity for

Layer

93 5 3.78 3,620 0 - 5 3.78 3,620 Mild

10 2.42 4,635 5 - 10 6.73 6,441 Mild

15 1.69 4,855 10 - 15 5.60 5,365 Mild

20 1.20 4,596 15 - 20 4.14 3,963 Mild

94 5 1.05 1,005 0 - 5 1.05 1,005 Moderate

10 0.59 1,130 5 - 10 1.35 1,290 Moderate

15 0.45 1,293 10 - 15 1.90 1,816 Moderate

20 0.42 1,609 15 - 20 6.30 6,033 Mild

95 5 4.52 4,328 0 - 5 4.52 4,328 Mild

10 0.92 1,762 5 - 10 1.16 1,106 Moderate

15 0.43 1,235 10 - 15 0.81 773 High

20 0.31 1,187 15 - 20 1.11 1,064 Moderate

96 5 1.44 1,379 0 - 5 1.44 1,379 Moderate

10 0.65 1,245 5 - 10 1.18 1,135 Moderate

15 0.38 1,092 10 - 15 0.91 876 High

20 0.27 1,034 15 - 20 0.93 893 High

97 5 2.48 2,375 0 - 5 2.48 2,375 Mild

10 0.94 1,800 5 - 10 1.51 1,450 Moderate

15 0.61 1,752 10 - 15 1.74 1,664 Moderate

20 0.50 1,915 15 - 20 2.77 2,655 Mild

98 5 2.19 2,097 0 - 5 2.19 2,097 Mild

10 1.24 2,375 5 - 10 2.86 2,737 Mild

15 0.81 2,327 10 - 15 2.34 2,237 Mild

20 0.56 2,145 15 - 20 1.81 1,737 Moderate

99 5 2.73 2,614 0 - 5 2.73 2,614 Mild

10 1.67 3,198 5 - 10 4.30 4,118 Mild

15 1.07 3,074 10 - 15 2.98 2,852 Mild

20 0.85 3,256 15 - 20 4.13 3,959 Mild

101 5 1.67 1,599 0 - 5 1.67 1,599 Moderate

10 0.84 1,609 5 - 10 1.69 1,618 Moderate

15 0.59 1,695 10 - 15 1.98 1,898 Moderate

20 0.53 2,030 15 - 20 5.21 4,990 Mild

103 5 1.50 1,436 0 - 5 1.50 1,436 Moderate

10 0.63 1,207 5 - 10 1.09 1,040 Moderate

15 0.45 1,293 10 - 15 1.58 1,508 Moderate

20 0.35 1,341 15 - 20 1.58 1,508 Moderate



| Project No. 19-0093 | A-13

Site

Number

Depth

(feet)

Resistance

to Depth

(ohm)

Resistivity

to Depth

(ohm-cm)

Layer

(feet)

Resistance

of Soil Layer

(ohm)

Resistivity

of Soil Layer

(ohm-cm)

Degree of

Corrosivity for

Layer

104 5 1.44 1,379 0 - 5 1.44 1,379 Moderate

10 0.59 1,130 5 - 10 1.00 957 High

15 0.49 1,408 10 - 15 2.89 2,768 Mild

20 0.44 1,685 15 - 20 4.31 4,129 Mild

105 5 1.67 1,599 0 - 5 1.67 1,599 Moderate

10 0.87 1,666 5 - 10 1.82 1,739 Moderate

15 0.65 1,867 10 - 15 2.57 2,461 Mild

20 0.46 1,762 15 - 20 1.57 1,507 Moderate

106 5 1.07 1,025 0 - 5 1.07 1,025 Moderate

10 0.55 1,053 5 - 10 1.13 1,084 Moderate

15 0.43 1,235 10 - 15 1.97 1,887 Moderate

20 0.35 1,341 15 - 20 1.88 1,801 Moderate

108 5 1.38 1,321 0 - 5 1.38 1,321 Moderate

10 0.65 1,245 5 - 10 1.23 1,177 Moderate

15 0.43 1,235 10 - 15 1.27 1,217 Moderate

20 0.41 1,570 15 - 20 8.81 8,441 Mild

109 5 1.86 1,781 0 - 5 1.86 1,781 Moderate

10 0.95 1,819 5 - 10 1.94 1,859 Moderate

15 0.58 1,666 10 - 15 1.49 1,426 Moderate

20 0.46 1,762 15 - 20 2.22 2,129 Mild

110 5 1.55 1,484 0 - 5 1.55 1,484 Moderate

10 0.67 1,283 5 - 10 1.18 1,130 Moderate

15 0.60 1,724 10 - 15 5.74 5,499 Mild

20 0.47 1,800 15 - 20 2.17 2,077 Mild

111 5 4.45 4,261 0 - 5 4.45 4,261 Mild

10 1.69 3,237 5 - 10 2.72 2,609 Mild

15 1.11 3,189 10 - 15 3.23 3,097 Mild

20 0.88 3,371 15 - 20 4.25 4,067 Mild

113 5 1.38 1,321 0 - 5 1.38 1,321 Moderate

10 0.68 1,302 5 - 10 1.34 1,284 Moderate

15 0.39 1,120 10 - 15 0.91 876 High

20 0.35 1,341 15 - 20 3.41 3,268 Mild

114 5 0.94 900 0 - 5 0.94 900 High

10 0.59 1,130 5 - 10 1.58 1,517 Moderate

15 0.48 1,379 10 - 15 2.57 2,465 Mild

20 0.42 1,609 15 - 20 3.36 3,217 Mild



| Project No. 19-0093 | A-14

Site

Number

Depth

(feet)

Resistance

to Depth

(ohm)

Resistivity

to Depth

(ohm-cm)

Layer

(feet)

Resistance

of Soil Layer

(ohm)

Resistivity

of Soil Layer

(ohm-cm)

Degree of

Corrosivity for

Layer

115 5 6.12 5,860 0 - 5 6.12 5,860 Mild

10 1.64 3,141 5 - 10 2.24 2,145 Mild

15 0.77 2,212 10 - 15 1.45 1,390 Moderate

20 0.48 1,839 15 - 20 1.27 1,220 Moderate

116 5 2.58 2,470 0 - 5 2.58 2,470 Mild

10 0.90 1,724 5 - 10 1.38 1,323 Moderate

15 0.53 1,523 10 - 15 1.29 1,234 Moderate

20 0.41 1,570 15 - 20 1.81 1,734 Moderate

117 5 2.25 2,155 0 - 5 2.25 2,155 Mild

10 0.86 1,647 5 - 10 1.39 1,333 Moderate

15 0.47 1,350 10 - 15 1.04 992 High

20 0.33 1,264 15 - 20 1.11 1,061 Moderate

118 5 1.72 1,647 0 - 5 1.72 1,647 Moderate

10 0.86 1,647 5 - 10 1.72 1,647 Moderate

15 0.76 2,183 10 - 15 6.54 6,259 Mild

20 0.69 2,643 15 - 20 7.49 7,173 Mild

119 5 1.53 1,465 0 - 5 1.53 1,465 Moderate

10 0.66 1,264 5 - 10 1.16 1,111 Moderate

15 0.49 1,408 10 - 15 1.90 1,822 Moderate

20 0.41 1,570 15 - 20 2.51 2,405 Mild

120 5 1.64 1,570 0 - 5 1.64 1,570 Moderate

10 0.78 1,494 5 - 10 1.49 1,424 Moderate

15 0.50 1,436 10 - 15 1.39 1,334 Moderate

20 0.37 1,417 15 - 20 1.42 1,363 Moderate

121 5 3.01 2,882 0 - 5 3.01 2,882 Mild

10 1.29 2,470 5 - 10 2.26 2,162 Mild

15 0.99 2,844 10 - 15 4.26 4,076 Mild

20 0.83 3,179 15 - 20 5.14 4,918 Mild

122 5 2.67 2,557 0 - 5 2.67 2,557 Mild

10 1.29 2,470 5 - 10 2.50 2,390 Mild

15 0.54 1,551 10 - 15 0.93 889 High

20 0.41 1,570 15 - 20 1.70 1,631 Moderate

123 5 0.90 862 0 - 5 0.90 862 High

10 0.68 1,302 5 - 10 2.78 2,664 Mild

15 0.54 1,551 10 - 15 2.62 2,512 Mild

20 0.41 1,570 15 - 20 1.70 1,631 Moderate



| Project No. 19-0093 | A-15

Site

Number

Depth

(feet)

Resistance

to Depth

(ohm)

Resistivity

to Depth

(ohm-cm)

Layer

(feet)

Resistance

of Soil Layer

(ohm)

Resistivity

of Soil Layer

(ohm-cm)

Degree of

Corrosivity for

Layer

125 5 1.75 1,676 0 - 5 1.75 1,676 Moderate

10 0.65 1,245 5 - 10 1.03 990 High

15 0.39 1,120 10 - 15 0.98 934 High

20 0.27 1,034 15 - 20 0.88 840 High

126 5 1.71 1,637 0 - 5 1.71 1,637 Moderate

10 0.94 1,800 5 - 10 2.09 1,999 Moderate

15 0.55 1,580 10 - 15 1.33 1,269 Moderate

20 0.36 1,379 15 - 20 1.04 998 High

128 5 1.70 1,628 0 - 5 1.70 1,628 Moderate

10 0.96 1,839 5 - 10 2.21 2,112 Mild

15 0.79 2,269 10 - 15 4.46 4,272 Mild

20 0.70 2,681 15 - 20 6.14 5,884 Mild

129 5 1.17 1,120 0 - 5 1.17 1,120 Moderate

10 0.60 1,149 5 - 10 1.23 1,179 Moderate

15 0.43 1,235 10 - 15 1.52 1,453 Moderate

20 0.32 1,226 15 - 20 1.25 1,198 Moderate

130 5 5.14 4,922 0 - 5 5.14 4,922 Mild

10 1.11 2,126 5 - 10 1.42 1,356 Moderate

15 0.72 2,068 10 - 15 2.05 1,962 Moderate

20 0.40 1,532 15 - 20 0.90 862 High

131 5 4.10 3,926 0 - 5 4.10 3,926 Mild

10 1.12 2,145 5 - 10 1.54 1,476 Moderate

15 0.64 1,839 10 - 15 1.49 1,430 Moderate

20 0.33 1,264 15 - 20 0.68 652 High

132 5 3.40 3,256 0 - 5 3.40 3,256 Mild

10 1.20 2,298 5 - 10 1.85 1,776 Moderate

15 0.61 1,752 10 - 15 1.24 1,188 Moderate

20 0.44 1,685 15 - 20 1.58 1,512 Moderate

134 5 3.79 3,629 0 - 5 3.79 3,629 Mild

10 0.94 1,800 5 - 10 1.25 1,197 Moderate

15 0.60 1,724 10 - 15 1.66 1,588 Moderate

20 0.32 1,226 15 - 20 0.69 657 High

135 5 8.97 8,589 0 - 5 8.97 8,589 Mild

10 1.00 1,915 5 - 10 1.13 1,078 Moderate

15 0.66 1,896 10 - 15 1.94 1,859 Moderate

20 0.36 1,379 15 - 20 0.79 758 High



| Project No. 19-0093 | A-16

Site

Number

Depth

(feet)

Resistance

to Depth

(ohm)

Resistivity

to Depth

(ohm-cm)

Layer

(feet)

Resistance

of Soil Layer

(ohm)

Resistivity

of Soil Layer

(ohm-cm)

Degree of

Corrosivity for

Layer

136 5 1.56 1,494 0 - 5 1.56 1,494 Moderate

10 0.85 1,628 5 - 10 1.87 1,788 Moderate

15 0.61 1,752 10 - 15 2.16 2,069 Mild

20 0.50 1,915 15 - 20 2.77 2,655 Mild

137 5 1.63 1,561 0 - 5 1.63 1,561 Moderate

10 0.68 1,302 5 - 10 1.17 1,117 Moderate

15 0.36 1,034 10 - 15 0.77 733 High

20 0.27 1,034 15 - 20 1.08 1,034 Moderate

139 5 2.30 2,202 0 - 5 2.30 2,202 Mild

10 1.61 3,083 5 - 10 5.37 5,139 Mild

15 0.73 2,097 10 - 15 1.34 1,279 Moderate

20 0.54 2,068 15 - 20 2.07 1,987 Moderate

140 5 5.19 4,970 0 - 5 5.19 4,970 Mild

10 1.98 3,792 5 - 10 3.20 3,065 Mild

15 1.07 3,074 10 - 15 2.33 2,229 Mild

20 0.55 2,107 15 - 20 1.13 1,084 Moderate

142 5 1.24 1,187 0 - 5 1.24 1,187 Moderate

10 0.53 1,015 5 - 10 0.93 886 High

15 0.30 862 10 - 15 0.69 662 High

20 0.23 881 15 - 20 0.99 944 High

143 5 3.12 2,988 0 - 5 3.12 2,988 Mild

10 1.01 1,934 5 - 10 1.49 1,430 Moderate

15 0.79 2,269 10 - 15 3.63 3,473 Mild

20 0.66 2,528 15 - 20 4.01 3,841 Mild

144 5 5.05 4,836 0 - 5 5.05 4,836 Mild

10 1.85 3,543 5 - 10 2.92 2,796 Mild

15 1.06 3,045 10 - 15 2.48 2,377 Mild

20 0.96 3,677 15 - 20 10.18 9,744 Mild

145 5 3.13 2,997 0 - 5 3.13 2,997 Mild

10 1.72 3,294 5 - 10 3.82 3,656 Mild

15 0.80 2,298 10 - 15 1.50 1,432 Moderate

20 0.40 1,532 15 - 20 0.80 766 High

146 5 0.76 728 0 - 5 0.76 728 High

10 0.44 843 5 - 10 1.05 1,001 Moderate

15 0.31 891 10 - 15 1.05 1,005 Moderate

20 0.26 996 15 - 20 1.61 1,544 Moderate



| Project No. 19-0093 | A-17

Site

Number

Depth

(feet)

Resistance

to Depth

(ohm)

Resistivity

to Depth

(ohm-cm)

Layer

(feet)

Resistance

of Soil Layer

(ohm)

Resistivity

of Soil Layer

(ohm-cm)

Degree of

Corrosivity for

Layer

148 5 2.00 1,915 0 - 5 2.00 1,915 Moderate

10 0.59 1,130 5 - 10 0.84 801 High

15 0.35 1,005 10 - 15 0.86 824 High

20 0.29 1,111 15 - 20 1.69 1,620 Moderate

149 5 2.20 2,107 0 - 5 2.20 2,107 Mild

10 1.01 1,934 5 - 10 1.87 1,788 Moderate

15 0.69 1,982 10 - 15 2.18 2,085 Mild

20 0.56 2,145 15 - 20 2.97 2,846 Mild

150 5 3.57 3,418 0 - 5 3.57 3,418 Mild

10 0.67 1,283 5 - 10 0.82 790 High

15 0.45 1,293 10 - 15 1.37 1,312 Moderate

20 0.35 1,341 15 - 20 1.58 1,508 Moderate

151 5 3.18 3,045 0 - 5 3.18 3,045 Mild

10 1.25 2,394 5 - 10 2.06 1,972 Moderate

15 0.87 2,499 10 - 15 2.86 2,740 Mild

20 0.61 2,336 15 - 20 2.04 1,955 Moderate

153 5 5.16 4,941 0 - 5 5.16 4,941 Mild

10 0.99 1,896 5 - 10 1.23 1,173 Moderate

15 0.47 1,350 10 - 15 0.89 857 High

20 0.35 1,341 15 - 20 1.37 1,313 Moderate

154 5 4.40 4,213 0 - 5 4.40 4,213 Mild

10 1.27 2,432 5 - 10 1.79 1,710 Moderate

15 1.00 2,873 10 - 15 4.70 4,504 Mild

20 0.68 2,605 15 - 20 2.13 2,035 Mild

155 5 1.26 1,207 0 - 5 1.26 1,207 Moderate

10 0.84 1,609 5 - 10 2.52 2,413 Mild

15 0.74 2,126 10 - 15 6.22 5,952 Mild

20 0.45 1,724 15 - 20 1.15 1,100 Moderate

156 5 1.64 1,570 0 - 5 1.64 1,570 Moderate

10 0.60 1,149 5 - 10 0.95 906 High

15 0.38 1,092 10 - 15 1.04 992 High

20 0.32 1,226 15 - 20 2.03 1,941 Moderate

157 5 1.29 1,235 0 - 5 1.29 1,235 Moderate

10 0.66 1,264 5 - 10 1.35 1,294 Moderate

15 0.48 1,379 10 - 15 1.76 1,685 Moderate

20 0.35 1,341 15 - 20 1.29 1,237 Moderate



| Project No. 19-0093 | A-18

Site

Number

Depth

(feet)

Resistance

to Depth

(ohm)

Resistivity

to Depth

(ohm-cm)

Layer

(feet)

Resistance

of Soil Layer

(ohm)

Resistivity

of Soil Layer

(ohm-cm)

Degree of

Corrosivity for

Layer

159 5 1.82 1,743 0 - 5 1.82 1,743 Moderate

10 0.55 1,053 5 - 10 0.79 755 High

15 0.39 1,120 10 - 15 1.34 1,284 Moderate

20 0.27 1,034 15 - 20 0.88 840 High

161 5 2.43 2,327 0 - 5 2.43 2,327 Mild

10 0.89 1,704 5 - 10 1.40 1,345 Moderate

15 0.58 1,666 10 - 15 1.67 1,594 Moderate

20 0.36 1,379 15 - 20 0.95 909 High

163 5 1.49 1,427 0 - 5 1.49 1,427 Moderate

10 0.74 1,417 5 - 10 1.47 1,408 Moderate

15 0.54 1,551 10 - 15 2.00 1,913 Moderate

20 0.52 1,992 15 - 20 14.04 13,444 Negligible

30 0.41 2,356 20 - 30 1.94 3,712 Mild

164 5 2.57 2,461 0 - 5 2.57 2,461 Mild

10 0.89 1,704 5 - 10 1.36 1,304 Moderate

15 0.69 1,982 10 - 15 3.07 2,940 Mild

20 0.62 2,375 15 - 20 6.11 5,852 Mild

165 5 3.45 3,304 0 - 5 3.45 3,304 Mild

10 2.42 4,635 5 - 10 8.11 7,762 Mild

15 2.09 6,004 10 - 15 15.33 14,676 Negligible

20 1.83 7,009 15 - 20 14.71 14,086 Negligible

166 5 1.63 1,561 0 - 5 1.63 1,561 Moderate

10 1.22 2,336 5 - 10 4.85 4,644 Mild

15 1.13 3,246 10 - 15 15.32 14,668 Negligible

20 0.64 2,451 15 - 20 1.48 1,413 Moderate

167 5 1.07 1,025 0 - 5 1.07 1,025 Moderate

10 0.45 862 5 - 10 0.78 744 High

15 0.31 891 10 - 15 1.00 954 High

20 0.23 881 15 - 20 0.89 853 High

168 5 1.14 1,092 0 - 5 1.14 1,092 Moderate

10 0.61 1,168 5 - 10 1.31 1,256 Moderate

15 0.40 1,149 10 - 15 1.16 1,113 Moderate

20 0.29 1,111 15 - 20 1.05 1,010 Moderate



| Project No. 19-0093 | A-19

Site

Number

Depth

(feet)

Resistance

to Depth

(ohm)

Resistivity

to Depth

(ohm-cm)

Layer

(feet)

Resistance

of Soil Layer

(ohm)

Resistivity

of Soil Layer

(ohm-cm)

Degree of

Corrosivity for

Layer

169 5 1.23 1,178 0 - 5 1.23 1,178 Moderate

10 0.49 938 5 - 10 0.81 780 High

15 0.33 948 10 - 15 1.01 968 High

20 0.24 919 15 - 20 0.88 843 High

170 5 1.74 1,666 0 - 5 1.74 1,666 Moderate

10 0.73 1,398 5 - 10 1.26 1,204 Moderate

15 0.53 1,523 10 - 15 1.93 1,852 Moderate

20 0.42 1,609 15 - 20 2.02 1,938 Moderate

30 0.31 1,781 20 - 30 1.18 2,267 Mild

171 5 1.02 977 0 - 5 1.02 977 High

10 0.58 1,111 5 - 10 1.34 1,287 Moderate

15 0.40 1,149 10 - 15 1.29 1,234 Moderate

20 0.35 1,341 15 - 20 2.80 2,681 Mild

172 5 3.50 3,351 0 - 5 3.50 3,351 Mild

10 1.21 2,317 5 - 10 1.85 1,771 Moderate

15 0.60 1,724 10 - 15 1.19 1,140 Moderate

20 0.39 1,494 15 - 20 1.11 1,067 Moderate

173 5 1.08 1,034 0 - 5 1.08 1,034 Moderate

10 0.59 1,130 5 - 10 1.30 1,245 Moderate

15 0.49 1,408 10 - 15 2.89 2,768 Mild

20 0.40 1,532 15 - 20 2.18 2,085 Mild

174 5 1.19 1,139 0 - 5 1.19 1,139 Moderate

10 0.72 1,379 5 - 10 1.82 1,746 Moderate

15 0.62 1,781 10 - 15 4.46 4,275 Mild

20 0.42 1,609 15 - 20 1.30 1,247 Moderate

175 5 0.97 929 0 - 5 0.97 929 High

10 0.50 958 5 - 10 1.03 988 High

15 0.34 977 10 - 15 1.06 1,017 Moderate

20 0.25 958 15 - 20 0.94 904 High

177 5 1.88 1,800 0 - 5 1.88 1,800 Moderate

10 0.77 1,475 5 - 10 1.30 1,249 Moderate

15 0.45 1,293 10 - 15 1.08 1,037 Moderate

20 0.28 1,072 15 - 20 0.74 710 High



| Project No. 19-0093 | A-20

Site

Number

Depth

(feet)

Resistance

to Depth

(ohm)

Resistivity

to Depth

(ohm-cm)

Layer

(feet)

Resistance

of Soil Layer

(ohm)

Resistivity

of Soil Layer

(ohm-cm)

Degree of

Corrosivity for

Layer

178 5 2.72 2,605 0 - 5 2.72 2,605 Mild

10 0.67 1,283 5 - 10 0.89 851 High

15 0.39 1,120 10 - 15 0.93 894 High

20 0.29 1,111 15 - 20 1.13 1,083 Moderate

179 5 1.34 1,283 0 - 5 1.34 1,283 Moderate

10 0.54 1,034 5 - 10 0.90 866 High

15 0.39 1,120 10 - 15 1.40 1,344 Moderate

20 0.32 1,226 15 - 20 1.78 1,707 Moderate

30 0.21 1,207 20 - 30 0.61 1,170 Moderate

180 5 1.33 1,274 0 - 5 1.33 1,274 Moderate

10 0.67 1,283 5 - 10 1.35 1,293 Moderate

15 0.44 1,264 10 - 15 1.28 1,227 Moderate

20 0.41 1,570 15 - 20 6.01 5,758 Mild

181 5 2.97 2,844 0 - 5 2.97 2,844 Mild

10 0.85 1,628 5 - 10 1.19 1,140 Moderate

15 0.51 1,465 10 - 15 1.28 1,221 Moderate

20 0.29 1,111 15 - 20 0.67 644 High

183 5 2.92 2,796 0 - 5 2.92 2,796 Mild

10 1.76 3,371 5 - 10 4.43 4,242 Mild

15 0.86 2,470 10 - 15 1.68 1,610 Moderate

20 0.59 2,260 15 - 20 1.88 1,799 Moderate

184 5 1.98 1,896 0 - 5 1.98 1,896 Moderate

10 1.17 2,241 5 - 10 2.86 2,739 Mild

15 0.79 2,269 10 - 15 2.43 2,329 Mild

20 0.57 2,183 15 - 20 2.05 1,960 Moderate

185 5 2.79 2,672 0 - 5 2.79 2,672 Mild

10 1.27 2,432 5 - 10 2.33 2,232 Mild

15 0.93 2,672 10 - 15 3.47 3,326 Mild

20 0.69 2,643 15 - 20 2.67 2,560 Mild

186 5 2.82 2,700 0 - 5 2.82 2,700 Mild

10 1.26 2,413 5 - 10 2.28 2,181 Mild

15 1.12 3,217 10 - 15 10.08 9,652 Mild

20 0.61 2,336 15 - 20 1.34 1,283 Moderate

Harvest Water Program: Corrosion Protection for Pipelines BODR Appendix B

In-situ Soil Resistivity Maps

| Project No. 19-0093 | B-1

Appendix B In-situ Soil Resistivity Maps



| Project No. 19-0093 | B-2

Figure B-1. In-situ Soil Resistivity Map Overview Designating Areas of Detailed Maps by Figure Number

B-2

B-3 B-4

B-5

B-6

B-7



| Project No. 19-0093 | B-3

Figure B-2. In-situ Soil Resistivity Detailed Map



| Project No. 19-0093 | B-4




| Project No. 19-0093 | B-5




| Project No. 19-0093 | B-6




| Project No. 19-0093 | B-7




| Project No. 19-0093 | B-8




| Project No. 19-0093 | B-9


Documents

Corrosion Protection for Pipelines Draft Basis of Design