Currents_Investigation_Final_ReportReducedSize.pdf

U.S. Army Corps of Engineers

CURRENTS INVESTIGATION

FINAL REPORT

September 21, 2010

Prepared For:

Chicago District 111 North Canal Street Chicago, IL 60606-7206

Prepared By:

Black & Veatch 6601 College Blvd

Overland Park, KS 66211

Page Left Intentionally Blank

Table of Contents

1.0 Purpose......................................................................................................................................... 1-1

2.0 Health and Safety Concerns ....................................................................................................... 2-1

2.1 Safety Concerns:....................................................................................................................... 2-1

2.2 Health Concerns: ..................................................................................................................... 2-4

3.0 Field Investigation – Equipment and Process........................................................................... 3-1

3.1 Voltage Measurements ............................................................................................................. 3-1

3.1.1 Field Test Equipment:.......................................................................................................... 3-2

3.1.2 Means and Method .............................................................................................................. 3-3

3.2 Soil and Water Resistivity Measurements................................................................................. 3-5

3.2.1 Field Test Equipment:.......................................................................................................... 3-6

3.2.2 Means and Method .............................................................................................................. 3-6

4.0 Field Data Measurements – Location of Strong and Weak Values ........................................ 4-1

4.1 Voltage Measurements ............................................................................................................. 4-1

4.1.1 Demonstration Barrier ......................................................................................................... 4-2

4.1.2 Fish Barrier 2A .................................................................................................................... 4-2

4.2 Measurements Comparison ...................................................................................................... 4-5

Table 4.1: Weather Data Recorded During Site Visits.......................................................................... 4-6

5.0 Corrosion Effects on Adjacent Utilities..................................................................................... 5-1

5.1 Background Information .......................................................................................................... 5-1

5.2 Corrosion Investigation............................................................................................................ 5-4

5.2.1 Barrier 2A Building Corrosion ............................................................................................ 5-4

5.2.2 Romeo Bridge Footing Corrosion........................................................................................ 5-4

5.2.3 Enbridge Pipeline ................................................................................................................ 5-5

5.2.4 Residential Utilities ............................................................................................................. 5-5

5.2.5 Railroad Tracks.................................................................................................................... 5-6

6.0 CDEGS Computer Model........................................................................................................... 6-1

6.1 Model Theory ........................................................................................................................... 6-1

6.2 Model Development.................................................................................................................. 6-4

6.3 Model Analysis ......................................................................................................................... 6-9

6.3.1 Calibration ......................................................................................................................... 6-10

6.3.2 Predictions of 2A & 2B Simultaneously Under Normal Operating Conditions ................ 6-13

6.3.3 Predictions of 2A With Increased Operating Conditions................................................... 6-13

6.3.4 Predictions of 2A & 2B Simultaneously With Increased Operating Conditions ............... 6-15

6.3.5 Predictions of Varying Soil Conditions ............................................................................. 6-15

6.3.6 Predictions of Varying Canal Conductivity ....................................................................... 6-15

6.4 Zone of Influence .................................................................................................................... 6-16

6.5 Conclusion.............................................................................................................................. 6-17

7.0 Probability of Adverse Impacts of Electric Gradients ............................................................. 7-1

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8.0 Methods to Reduce the Site Electric Gradient Potential ......................................................... 8-1

8.1 Alternatives for Existing Fencing............................................................................................. 8-2

8.1.1 Improved Grounding. .......................................................................................................... 8-2

8.1.2 Non-Conductive Fencing..................................................................................................... 8-3

8.2 Concrete Foundations .............................................................................................................. 8-4

8.3 Personal Property Owners/Residents....................................................................................... 8-5

8.4 Residential Propane Tanks....................................................................................................... 8-5

8.5 Natural Gas Pipeline................................................................................................................ 8-5

8.6 System Operation ..................................................................................................................... 8-5

8.7 Midwest Generation Fence Line............................................................................................... 8-6

8.8 Isolation of Electrical Energy .................................................................................................. 8-6

8.9 Future Construction and Renovations...................................................................................... 8-6

9.0 Best Practices for Grounding Equipment and Structures in Vicinity of the Fish Barrier ... 9-1

9.1 General Electrical Grounding Principles ................................................................................ 9-1

9.2 Fences In the Vicinity of Fish Barrier ...................................................................................... 9-1

10.0 Other Concerns and Unknowns............................................................................................... 10-1

10.1 Temporary Construction Facilities ........................................................................................ 10-1

10.2 Transferred Potentials............................................................................................................ 10-1

10.3 Changing of Barrier Parameters............................................................................................ 10-2

10.4 Local Well Pumps................................................................................................................... 10-2

11.0 Summary.................................................................................................................................... 11-1

Appendices

Appendix A: Field Measurements Data Appendix B: CDEGS Computer Soil Data Appendix C: Site Overview Map Appendix D: Electrical Signal Maps Appendix E: Non-Conductive Fence Options Appendix F: Grounding Details Appendix G: Midwest Generation Observed Grounding Details Appendix H: Soil and Water Resistivity Data Appendix I: RMS Sample Calculations Appendix J: Instruments and Calibration Information Appendix K: February 19th Draft Report Appendix L: Professional Peer Review

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1.0 Purpose

The objectives of this report are to collect and gather information on the earth surface potential gradients in the areas surrounding the demonstration fish barrier, fish barrier 2A, and future fish barrier 2B. The results of the data gathered will be used to determine the immediate effects of the demonstration fish barrier and fish barrier 2A on personal safety, as well as the possible impacts of future fish barrier 2B. The data and physical information will be used as input in the Current Distribution, Electromagnetic

Fields, Grounding and Soil Structure Analysis (CDEGS) software, to model different fish barrier operating scenarios and possible mitigations. In addition to modeling the different scenarios, this report will provide information on how and where field data was gathered, provide graphical representation based on the findings, identify potential adverse impacts in the immediate area and surroundings, and include discussion of possible solutions.

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2.0 Health and Safety Concerns

The fish barrier consists of pairs of electrode arrays arranged near the bottom of the Chicago Sanitary and Ship Canal (Chicago Canal) and oriented perpendicular to the water flow. DC voltage pulses applied between the electrode pairs creates electric field gradients in the water and surrounding soil adjacent to the fish barrier installation.

Generally, the electric energy measured in the ground adjacent to the canal is considered low voltage. When a person walks on the ground adjacent to the fish barrier along the high bank of the canal, he is essentially walking on ground that has elevated voltage gradients when compared to a remote reference point. Unless proper precautions are taken, the different potential gradients along the earth’s surface may be of sufficient magnitude to endanger people in the area. Site conditions will often change such as;

weather and soil conditions, increased output from the fish barriers or physical changes such as signs new and old fencing. Precaution should always be taken as these changes in condition can increase the potential shock hazards. In this report health and safety concerns are evaluated on the basis of electric potentials and the resulting electrical current flowing through the body.

2.1 Safety Concerns:

Electric energy present in the earth due to the fish barriers varies in all directions.

This variation is predominately the result of the soil/rock resistivity and the variation in the magnitude of the DC pulses produced by the fish barriers. The electric energy dissipates with distance from the fish barriers’ electrodes. The electric energy may vary across small distances (3 to 5 feet). The amount of electric energy present in fencing, signs and other metal items embedded in the ground will vary as well. The variation in electric energy is characterized as electric potential gradients. When a person bridges the gap between two electric potential gradients of different levels, current may flow through the person, equalizing the potentials. The magnitude of the current the human is exposed to is the result of the person’s resistance and the difference between the two electric gradients. The Institute of Electrical and Electronics Engineers (IEEE) defines the following types of electric potential exposures for a human:

• Touch Potential: The potential difference between the ground potential rise and the surface potential at the point where a person is standing while at the same time having a hand in contact with a grounded structure.

• Reach Potential or Metal-to-Metal Touch Potential: The difference in potential between metallic objects or structures that may be bridged by direct

2-1 hand-to-hand or hand-to-feet contact. Most reach potentials are present where there is a possibility for a person to be touching two conductive grounded structures at the same time. Reach potentials include: between metallic hand rails, between chain link gates that are not electrically bonded, between permanent grounded and temporary fences, and between metallic signage and fencing.

• Step Potential: The difference in surface potential experienced by a person bridging a distance of 1 meter with the feet without contacting any grounded object.

Typically exposure of a human to electricity is evaluated based on exposure to

AC electrical systems. The nature of the DC pulse emanating from the fish barrier has an

AC component. The safety issues associated with exposure to an AC system is applicable to the situation that has developed adjacent to the fish barrier. In order to make judgments regarding health and safety concerns, the RMS Values are used for evaluation. The effective value of the AC component and DC component from the fish barriers is referred to as the RMS Value.

AC potentials on structures must be maintained at safe levels to prevent shock hazards to people. The degree of shock hazard and the threshold levels of current that can be tolerated by human beings depend on many factors. The possibility of shock from lower voltages is the most difficult to assess. The degree of shock hazard depends on factors such as the voltage level and duration of human exposure, human body weight, human skin conditions, and the path and magnitude of any current conducted by the human body. The magnitude of current conducted by the human body is a function of the internal impedance of the voltage source, the voltage impressed across the human body, and the electrical resistance of the body path. This resistance also depends on the contact resistance (e.g., wet or dry skin, standing on dry land or in water), and on the current path through the body (e.g., hand-to-foot, hand-to-hand, etc.). Tables 2.1 and 2.2 indicate the probable human resistance to electrical current and current values affecting humans.

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Table 2.1

Human Resistance to Electrical Current

Current Path Resistance

Dry skin 100,000 to 600,000 ohms

Wet skin 1,000 ohms

Internal body hand to foot

400 to 600 ohms

Ear to ear about 100 ohms

NACE SP0177-2007, “Mitigation of Alternating Current and Lightning Effects on Metallic Structures and Corrosion Control Systems.”

Table 2.2 Effects of 60 Hz AC Body Currents on Humans

Current mA) Physiological Effect

<1 No Sensation

1 to 8 Threshold of perception, painless

8 to 15 Painful, no loss of muscular control

15 to 20 Painful, loss of muscular control, can’t let go

20 to 50 Painful, severe muscular contractions, breathing difficulties

50 to 100 Ventricular fibrillation possible

100 to 200 Fibrillation certain, death results without defibrillation

>200 Severe burns, severe muscular contractions

NACE SP0177-2007, “Mitigation of Alternating Current and Lightning Effects on Metallic Structures and Corrosion Control Systems.”

Small electrical shocks can be a risk and can potentially cause an involuntary movement that may cause an accident. However; the smallest shock of significance is the current at which a person loses voluntary muscular control and cannot let go of an energized object. The maximum current at which a person can still let go is known as the let-go current. This is considered the maximum possible current for sustained shocks because a person can withstand repeated exposure to their let-go current without serious after-effects.

As current increases beyond the let-go current, shocks become increasingly painful and more dangerous to the body. The most serious shock hazard occurs when

2-3 currents are capable of causing ventricular fibrillation. When ventricular fibrillation occurs, the electrical signals to the heart become disrupted and the heart stops pumping.

Under these circumstances, the heart almost never starts pumping again on its own and death can only be prevented by administering cardiopulmonary resuscitation (CPR) until defibrillation can be applied.

Dry skin has a resistance range of 100KΩ to 600KΩ while the generally excepted value of wet human skin can be as low as 1000Ω. For the purpose of this report the available current will be calculated using the formula:

Current = Voltage/ Resistance.

The measured RMS values will be used for the voltage and 1000Ω (wet human skin) for the resistance. See Appendix A for Measured rms voltage and calculated current.

There are other accepted standards for the effects of 60 Hz AC current of the human body. Other accepted standards have slightly different descriptions and range of current values. The NACE SP0177-2007 effect of body currents on humans (see Table

2.2) breaks down the current values in to more detail than the other standards such as

IEEE 80 or OSHA.

When comparing the highest current for the demonstration fish barrier of 8.3mA to the NACE Table 2 above, the value is on the lower end of the 8-15mA “Painful, no loss of muscular control” physiological effect description. This category is considered unpleasant and painful, but tolerable and not a life safety hazard.

When comparing the highest current calculated for fish barrier 2A of 60-70mA to the NACE Table 2.2 above, the value is in the middle of the 50 to 100mA “Ventricular fibrillation possible” physiological effect description. This does not imply that ventricular fibrillation will occur; rather it indicates that ventricular fibrillation is a distinct possibility. A current in the 60-70mA range will cause severe muscular contractions, inability to “let go” and breathing difficulties, creating a life safety hazard.

Based on the modeling results and using judgment gained through understanding of how the fish barrier systems operates, current levels will most likely increase when barrier 2B is in operation. There is the distinct possibility that other locations will develop higher current levels.

2.2 Health Concerns:

The immediate concern associated with exposure to voltage is from a safety perspective. The field testing performed indicated that the main source of electrical current was coming through the ground from the DC pulses and not from an EMF

(electromagnetic field) generated by the Fish Barrier system.

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Health concerns have traditionally been evaluated on the basis of long term exposure to electromagnetic fields (EMFs). A review of reports located on the internet revealed that health concerns associated with exposure to EMFs have been evaluated for overhead lines, and localized exposure to fields created by equipment. The following are two applicable references that discuss health concerns associated with exposure to EMFs:

• Electromagnetic Fields: A Consumer's Guide to the Issues and How to Protect

Ourselves, Authored by B. Blake Levitt, Published by iUniverse.Inc, 1995 and

2007.

• Effects of high-intensity power-frequency electric fields on implanted modern multiprogrammable cardiac pacemakers'; Authored by: G S Butrous MB chB

S J Meldrum BSC PhD, Departments of Cardiology and Medical Electronics, St Bartholomew's Hospital, London EC; D G Barton MB MSC J C Male BSC

PhD

Based on field measurements performed, there is generally very little or no EMF present along the high banks of the canal and landward from the canal. In addition to the field testing, a report was reviewed documenting evaluation of EMFs associated with the

Fish Barrier system. This report is entitled:

• Magnetic Field Range-Finding Exposure Assessment of Extremely Low

Frequency (ELF) Fish Barriers, Published by the Federal Occupational

Health, dated December 15, 2009.

This report indicates that the exposure to EMF in the vicinity of the Fish Barrier is well within acceptable limits. There are localized EMFs near the electrodes entering the canal on fish barrier 2A that were detected by a site visit.

Additional research into pulsed electric fields revealed that there is interest within the Scientific and Medical communities regarding effects on human and non-human biology. The following three articles discuss various aspects of exposure to pulsed current:

• The Effect of Pulsed Electric Fields on Biological Cells: Experiments and

Applications, Authored by Karl H. Schoenbach, Fellow, IEEE; Frank E.

Peterkin; Raymond W. Alden, III; and Stephen J. Beebe, Published in the

IEEE Transactions on Plasma Science, Vol. 25, No. 2, April 1997

• Increased Cell Killing and DNA Damage in Cells Exposed to Ultra-Short

Pulsed Electrical Fields, Authored by M. Stacey, J. Stickley, P. Fox, C.

O’Donnell, K. Schoenbach, S. Beebe, and S. Buescher, Published in the 2002

Annual Report Conference on Electrical Insulation and Dielectric Phenomena

• Differential Effects in Cells Exposed to Ultra-Short, High Intensity Electric

Fields: Cell Survival, DNA Damage, and Cell Cycle Analysis, Authored by

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M. Stacey, J. Stickley, P. Fox, V. Statler, K. Schoenbach, S. J. Beebe, and S.

Buescher, Published by Elsevier B.V., 2003. Available on line at www.sciencedirect.com

These three publications indicate that cell damage could be possible if exposed directly to a pulsed electric field. These experiments were performed on the basis of direct exposure or introduction of the pulse electric field into the cell or groups of cells.

Based on this understanding, a person would have to be in the water within the Fish

Barrier electrical field to be exposed directly to the pulsed electric field. It is not clear if there would be any health concerns for a person walking along the high banks. When a person walks along the high banks or within the vicinity of the high banks, the electrical current generally will not enter their body as long as they are wearing rubber soled shoes or do not bridge differential potentials that allow the electricity to flow through the body.

2-6 http://www.sciencedirect.com/

3.0 Field Investigation – Equipment and Process

The field investigation process evolved over time as the Project Team gathered data and began to understand the impact of the fish barriers on the surrounding area. The intent of the initial field investigation was to take measurements and gather information to help determine how the fish barrier signal was propagating.

Measurements between a suspended antenna and a ground rod were taken to determine whether or not the chain link fence along the canal could be acting as an antenna. The antenna setup included a solid bare copper wire attached to a 1000 Ω resistor and the meter tied to ground through a metal plate or ground rod. The antenna was run through a piece of PVC pipe for support purposes and suspended across two ladders. The antenna was lengthened and shortened at variable lengths with the grounding plate and with the grounding rod to gather signals. The antenna was also suspended at various heights above the ground to note changes due to the distance between the antenna and ground. The last modification to the setup changed the orientation of the ladder. The antenna was placed in either a north south orientation running parallel to the canal or in an east/west orientation putting the antenna perpendicular to the canal. The antenna measurements were taken adjacent to the fish barrier electrodes because of high electrical signals measured between a ground rod and chain link fence. Suspended antenna RMS voltage values ranged from 69mV to 200mV, suggesting electrical signals are being propagated through the ground. Measurements of the electric signal between a ground rod and the fence reinforced the idea that the electrical energy in the fence was being introduced through the ground.

Once this data was evaluated, the Project Team determined that a better method for establishing a ground was required. The measurements taken in February may have been hindered by the inability to establish a proper ground. The primary method used to establish a ground was to drive a copper clad ground rod into the soil surface. After consultation with grounding experts it was determined that a better ground reference could be established by using a copper-copper sulfate reference electrode. A copper-copper sulfate reference electrode will produce repeatable results, keeping field measurements consistent. The field measurements taken in April, May and July are considered more reliable than the measurements taken in February.

3.1 Voltage Measurements

The majority of data was collected during the weeks of April 5, April 13, May 5, 3-1

July 12 and July 20, 2010. See Appendix A for Field Measurement Data. The remainder of the data was gathered during the week of February 15, 2010 and can be found in

Appendix K in the Draft Report submitted on February 19, 2010. During each site visit weather conditions such as humidity, temperature, and precipitation varied as documented in Table 4.1. Soil resistivity measurements were taken in six different locations on both the east and west side of the Chicago Canal. Water samples were taken from flooded woodlands, I&M Canal, and the quarry on the property. Both water and soil sample locations are indicated on the Site Overview Map in Appendix C. Readings were taken by measuring the voltage across conductive objects (reach potentials), conductive object and reference ground electrode (touch potentials), and between reference ground electrodes (step potentials). The test point locations are indicated on the

Site Overview Map in Appendix C and the test point data can be found in Appendix K for February measured data and Appendix A for Field Measurement Data. The possible touch and reach potentials changed from each site visit as the construction of fish barrier

2B progressed and mitigations were in place.

3.1.1 Field Test Equipment:

The field measurements at the sample locations were carried out using a Trimble

GeoExplorer 2008 Series GeoXH handheld GPS unit pre-loaded with ESRI’s ArcPad 7.1 software. The GeoExplorer 2008 series has an accuracy of 1 to 3 meters (3 to 9 feet) and under ideal conditions can have submeter accuracy. There were, however, a variety of factors (overcast skies, road overpass, overhead power lines etc.) encountered while in the field which made it difficult to achieve submeter accuracy, but had no effect on establishing contact with a sufficient number of satellites to ensure that all points were collected within the 1 to 3 meter accuracy.

The maps contained herein were produced using the data management and layout functionality within ESRI ’s ArcMap 9.3 GIS software platform. All data used in the production of the maps not provided by either the USACE Chicago District or created were obtained free of charge from public data sources.

FLUKE Industrial scopemeters Model Number 123 with software version V02.00 were used to take potential measurements for this report. The Fluke scopemeters can be used to take measurements such as peak-to-peak voltages, DC voltages, and root mean square (RMS) voltages. The scopemeter can also be used to capture the wave form displayed on the screen at the time of the measurement.

Ground references were established by the use of copper-copper sulfate reference electrodes. Each reference electrode consists of a container holding a copper rod and a

3-2 saturated solution of copper sulfate with a porous ceramic plug allowing contact with the ground. Reference electrodes were used to measure step and touch potentials. See

Appendix J for more information on the reference electrodes, the Fluke Scopemeter, certificates of calibration, and other instruments used during the data gathering process.

3.1.2 Means and Method

Touch Potential - During the field investigation, touch potentials were measured between a copper-copper sulfate reference electrode contacting the soil and a grounded structure. The reference electrode was placed approximately 1 meter from the metallic structure representing the reach of an adult while standing. During each measurement the same polarity was kept with the meter. The common (black) wire was connected to the reference electrode placed on the ground, while the positive (red) wire was connected to the grounded object such as a metal fence post. The majority of the grounded structures were chain link fences, both permanent and temporary. Other structures measured include warning signs, light pole equipment with direct contact to the earth, pole grounding cable, and guy wire anchors. See Figure 3.1 and 3.4 for an example of a touch potential situation (Figure 3.4 taken from IEEE Std 80-2000).

Figure 3.1: Touch Potential Situation

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Reach Potential - Most reach potentials are present where there is a possibility for a person to be touching two conductive grounded structures at the same time. Reach potentials include: between metallic hand rails, between chain link gates that are not electrically bonded, between permanent grounded and temporary fences, and between metallic signage and fencing. See Figure 3.2 and 3.4 for an example of reach (metal-to-metal) potential situation

Figure 3.2: Reach Potential Situation

Step Potential - Step potentials were measured between two copper-copper sulfate reference electrodes placed approximately 1 meter apart. Each reference electrode represents an individual’s feet spaced 1 meter apart. Step potential measurements were taken using reference electrodes oriented perpendicular and parallel to the Chicago Canal.

See Figure 3.3 and 3.4 for an example of step potential

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Figure 3.3: Step Potential Situation

Figure 3.4—IEEE Figure of basic shock situations

3.2 Soil and Water Resistivity Measurements

The field investigation included measurements of the soil resistivity at six locations adjacent to the fish barrier site. Water resistivity measurements were performed on ground water west of the Chicago Canal, on a sample from the Illinois & Michigan

Canal, and on a sample obtained from the quarry east of the Chicago Canal. See

Appendix A for soil measurement location and Appendix H for Soil Resistivity Data.

Information obtained from these measurements is used to develop the CDEGS soil analysis.

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3.2.1 Field Test Equipment:

The soil and water resistivity measurements were performed using an Advanced

Geosciences MiniSting earth resistivity meter, serial number S0610119. Information and data on this instrument can be found in Appendix J.

3.2.2 Means and Method

The soil resistivity testing was performed using the Wenner Four-Electrode

Method in accordance with ASTM G57. The Wenner four-electrode method requires that four metal electrodes be placed with equal separation in a straight line in the surface of the soil to a depth not exceeding 5 % of the minimum separation of the electrodes. The resulting resistivity measurement represents the average resistivity of a hemisphere of soil of a radius equal to the electrode separation distance “A”. A voltage is impressed between the outer electrodes, causing current to flow, and the voltage drop between the inner electrodes is measured using the earth resistivity meter which displays the resistance measured and the soil resistivity. Refer to Figure 3.5 and 3.6 for diagrams of the soil resistivity measurement procedure:

Figure 3.5 – Wenner Four Electrode Method for Measuring Soil Resistivity

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Figure 3.6: Soil Resistivity Procedure

Soil resistivity varies with depth and also in horizontal directions. Measurements were performed at six locations using electrode "A" spacings of 1, 2, 3, 6, 10, 20, 30, and

50 feet. Use of multiple “A” spacing’s at each location allows for development of a soil model by layers. The resistivity, ρ, is then calculated from the resistance value obtained as follows:

ρ, ohm·cm = 2π aR Where:

a = electrode separation in cm, and

R = resistance, in ohms.

Electrical resistivity measurements were performed on water samples using the

AGI Ministing meter and an MC Miller soil box as indicated in Figure 3.7. The multiplication factor for the Soil Box is 1 when the soil box is filled level. When used with a soil resistance meter, no calculations are necessary because the multiplication factor is 1 ohm-cm. Therefore, the resistivity value of the sample can be read directly from the meter resistance value. Refer to Appendix H for soil resistivity and water resistivity test results.

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Figure 3.7 – Soil Box Method for Measuring Water Resistivity

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4.0 Field Data Measurements – Location of Strong and Weak

Values

The process of gathering field data focused on acquiring relevant information related to the various potentials that a person might be exposed to when working or entering the areas adjacent to the fish barrier. The intent of the data gathering was to determine the extent of the fish barrier electrical influence in the adjacent areas. The field measurements confirmed that the electrical energy present in the ground peaks near the fish barrier and dissipates with distance away from the fish barrier. The Fish barrier

DC pulse was detectable in some areas approximately 400 feet landward from the East high bank of the canal and approximately 800 feet landward from the West high bank of the canal (along the Northern Midwest Generation property fence line). The measured potentials varied significantly across this distance. There may be localized points outside of this area that have measureable electric potential that is the result of the fish barrier electrical energy. Factors that might allow this to occur include local soil/rock resistivity, water table elevation and resistivity and depth of metal item. A map has been created that portrays the measured surface voltage, (reference electrode to reference electrode and reference electrode to grounded objects) gradients around the fish barriers, see Appendix

D “Measured Extent of Surface Influence” map. The map incorporated all points taken with 2 colored areas: the inner orange color shape represents the area where the fish barrier DC pulse could be detected, while the outer yellow color shape represents the area where the fish barrier DC pulse was not detected or distinguished from other signals.

4.1 Voltage Measurements

At each test location voltage measurements were taken to represent three different basic hazards: touch, step, and reach (metal-to-metal) potentials. Touch and reach potentials were measured where grounded structures were available, such as metallic fencing, signs, and handrails. In areas of cleared grounds and open fields without grounded structures, only step potential measurements were taken. Step potential measurements were taken parallel and perpendicular to the Chicago Canal to capture variations in the electric field. Locations where measurements were can be seen on the site overview map in Appendix C. A summary of the voltage readings and calculated current levels are summarized in Appendix A.

Whether it is step, touch, or reach potential, three separate values were measured:

DC component, RMS value, and peak-to-peak. The RMS value is defined as the effective power for a wave form. Each barrier produces a DC pulse or pulses that

4-1 inherently have an AC component. As the DC pulse frequency and width changes so does the AC component. Some of the wave forms captured with the scope-meter indicated change in the pulse polarity (see Figure 4.1), thus increasing the peak-to-peak voltage, but not the RMS voltage. If the frequency of the pulses is increased while maintaining the same pulse width and amplitude, the RMS value or effective power will increase and peak-to-peak voltage will remain the same. Therefore, the RMS or effective voltage measured from the barriers was used as the voltage to calculate the possible current through the human body. See Appendix I for sample RMS calculations.

Measurements were taken around fish barrier 2A and the demonstration fish

Barrier. In most cases the DC signature pulse dissipated with distance from each barrier, as anticipated.

4.1.1 Demonstration Barrier

The demonstration fish barrier uses about 10 times less power then fish barrier 2A and thus the voltage measurements around the demonstration fish barrier are much lower.

There was a DC signature detected on the chain link fence around the mechanical pipe bridge north of the demonstration fish barrier (Points 36, 199, and 200 on the map).

However, the DC voltage that was measured is assumed to be part of the pipe line cathodic protection system. Very little, if any, influence from the demonstration fish barrier could be detected along the chain link fence between the quarry and rail road track

(Points 104, 105, and 106 on the map). Measurements on the fence around the demonstration fish barrier trailer on the east side and the electrode fence on the west side averaged around 3 to 3.5 Vrms. The highest reading measured for the demonstration fish barrier was 8.3 Vrms, between the temporary fence and ground, along the Chicago Canal

100 feet north of the demonstration fish barrier (Point 85 on the map).

4.1.2 Fish Barrier 2A

The influence of fish barrier 2A affects a much larger area and is significantly higher in magnitude than the demonstration fish barrier. Fish barrier 2A signals can be detected along the permanent chain link fence on each side of the Chicago Canal, gradually declining the further away from the source. At the corner of the fence line on the south side between the coal power plant and Romeo Road the signal dissipates but still can be detected at Point 163. The Chicago Canal front property next to the Midwest

Generation power plant had small reach potential values between the grading, rail tracks, metallic signage, and barge tie-offs. The 2A fish barrier was most influential at Point

133. Signals from fish barrier 2A were not detected along the refinery west parking lot

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(Points 117 through 123). A very slight signal of 0.9 Vrms was measured across the

I&M Canal (Point 107).

Measurements were also taken along the BNSF railroad track on the East side of the Chicago Canal (Points 298 through 331). Data was measured between each set of rails, between individual train tracks, from each set of train tracks to ground and from each set of train tracks and the track ballast (crushed rock approximately 3ft from the track). The voltage readings between the train tracks was insignificant while the voltage between the train tracks and ground increased in magnitude the closer the measurements were to the fish barrier

The highest measurements taken around fish barrier 2A were along the permanent and temporary chain link fence on both sides of the Chicago Canal. Points 19, 20, 78

126, 222 and 223 had touch potentials (ground-to-fence) above 30 to 64 Vrms, while reach potentials between permanent and temporary fence were 47 to 61.3 Vrms.

The waveforms from the DC pulses changed from point to point. There were four

DC pulse pattern observed on the scope-meter while readings were being taken during the various site visits. Below is a collection of captured DC pulses from Fish barrier identifying each pattern observed with a brief description.

Figure 4.1 Positive & Negative DC Pulses

Figure 4.1 illustrates where wide and narrow array pulses have opposite polarity.

It appears that the smaller pulse (wide array) is negative and the larger pulse (narrow array) is positive with a frequency of about 15 Hz. This waveform was detected at map point 20.

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Figure 4.2 Positive DC Pulses

Figure 4.2 illustrates where both DC pulses have positive polarity with a frequency of about 15 Hz. This waveform was detected at map point 158.

Figure 4.3 Negative DC Pulses

Figure 4.3 illustrates where both pulses have negative polarity with a frequency of about 15 Hz. This waveform was detected at map point 195.

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Figure 4.4 Overlapping DC Pulses

Figure 4.4 illustrates where the pulses are overlapping with a frequency of about

15 Hz. This waveform was detected at map point 72.

4.2 Measurements Comparison

There are several factors that can attribute to different values taken in the same location from day-to-day and month-to-month. While it is difficult to pin point only one reason, a few of the major contributing factors are weather conditions and conductivity of the canal water.

The weather conditions varied each trip: February weather conditions consisted of dry, frozen soil with snow on the ground, April weather conditions consisted of wet, rain with saturated unfrozen ground, and May weather consisted of dry conditions with no standing water. Soil moisture at different elevations in the ground will affect the resistance of the current. The weather data for each of the site visits is listed in Table 4.1 below.

The conductivity variance in the canal water has a direct correlation to the intensity or power output of the barriers. As conductivity in the Chicago Canal water increases then more power is required to maintain a predetermined volt per inch on the surface of the Chicago Canal water and as conductivity decrease lower power output is required to maintain the same volts per inch value.

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Table 4.1: Weather Data Recorded During Site Visits

Date High Temp (ºF) Low Temp (ºF) Precipitation Observed Data 2/16/2010 32 25 0 Frozen conditions and cool temperatures 2/17/2010 32 26 <1 Frozen conditions and cool temperatures 4/5/2010 72 50 0.82 Heavy rain with pooling water 4/6/2010 76 47 0.37 Cloudy with showers (pooling water) 4/7/2010 49 37 0.13 Partly Cloudy (pools of water) 4/8/2010 40 34 0 Partly Cloudy

4/13/2010 63 48 0 Partly cloudy 5/5/2010 72 56 0 Sunny and dry

7/12/2010 84 65 0 Humid, cloudy with light rain fall 7/13/2010 84 70 0.17 Humid and partly cloudy 7/20/2010 86 68 <1 Very humid sunny 7/21/2010 91 72 0 Very humid sunny

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5.0 Corrosion Effects on Adjacent Utilities

The electrical energy that migrates into the ground from the fish barrier can cause corrosion of metal items. The corrosion of the metal items will be limited to the areas where the electrical potentials can be detected. As indicated, electric potentials were detected 400 feet and 800 feet landward of the East and West banks of the canal, respectively. Thus, metal items in this area have the possibility of being exposed to corrosion resulting from the fish barrier electrical energy. However, there may be metal items outside this area that experience increase corrosion due to influence from the fish barrier electrical energy. Factors that might allow this to occur include local soil/rock resistivity, water table elevation, and resistivity and depth of metal items.

5.1 Background Information

The fish barriers intentionally introduce a pulsed DC electrical current in the

Chicago Canal. This signal migrated into the surrounding earth. This DC electrical current may also unintentionally flow through metallic structures located in the soil, such as piping, concrete reinforcing steel, fence posts, etc and is commonly referred to in industry as “stray current”. Stray current is defined as current in an unintended path.

Figure 5.1 indicates a typical stray current situation on an underground metallic structure that is not electrically connected to the source of stray current. The stray current pattern consists of a pick-up of stray current from the earth at one or more locations and the subsequent discharge of stray current to the earth at one or more locations.

Figure 5.1 – NACE Figure of Typical Stray Current Interference on a Metallic Underground Structure

The effect of a stray current pick-up and a stray current discharge from an iron structure from a thermodynamic perspective can cause corrosion, passivation, or immunity, depending upon the direction of current and the pH of the aqueous electrolyte at the charge transfer location.

Identification of the current discharge site receives considerable attention in stray current investigations because it is the location where corrosion damage is most likely to

5-1 occur on all metallic structures. When a current transfers from a metallic structure to earth (Figure 5.2), it must do so via an oxidation reaction that converts electronic current to ionic current.

Figure 5.2 – NACE Figure of Current Discharge from a Metal Structure to Earth via an Oxidation Reaction

On an iron or steel structure without cathodic protection, the oxidation reaction is usually the dissolution (corrosion) of the metal according to the following equation:

Fe0

= Fe++ + 2e–

The severity of corrosion depends on the magnitude of the stray current and time as related by Faraday’s Law. The consumption rate of metals discharging one ampere of

DC current for one year is indicated in Table 5.1. Stray current can cause rapid corrosion of steel structures at a rate of 9.13 kg of steel corroded for each amp-year of current discharge.

At the area of current pick-up, a negative shift will result in cathodic polarization.

If the foreign structure is mild steel, then there is a beneficial effect because the structure is receiving some measure of cathodic protection.

Stray current in a metallic structure does not usually cause damaging effects between the stray current pick-up and discharge locations unless the current is very large or the structure is not electrically continuous. If the structure is electrically discontinuous

(as is often the case with cast iron water distribution piping or PCCP transmission piping), the structure resistance (Rs) is greater than if it were electrically continuous, which reduces the magnitude of Is, but creates a current discharge/current pick-up pattern at each electrical discontinuity (Figures 5.3 and 5.4).

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Figure 5.3-Stray Current Discharge and Pick-Up Around an Electrically Discontinuous Joint Through the

Earth (from NACE CP Interference)

Table 5.1 Theoretical Consumption Rate of Various Metals and Substances

From NACE CP Interference

Reduced Species

Oxidized Species

Molecular Weight, M

(g)

Electrons Transferred

(n)

Equivalent Weight, M/n

(g)

Theoretical Consumption Rate

(Kg/A-y)

Al

Al+++ 26.98 3 8.99 2.94

Cd Cd++ 112.4 2 56.2 18.4

Be Be++ 9.01 2 4.51 1.47

Cr

Cr++

52.00 2 17.3 5.65

Cu

Cu++

63.54 2 31.77 10.38

H2

H2++

2.00 2 1.00 0.33

Fe

Fe++ 55.85 2 27.93 9.13

Zn Zn++ 65.37 2 32.69 10.7

In many of these structures not every joint is discontinuous, but localized corrosion will occur on the discharge side of the discontinuous joints. Furthermore, on water and sewer piping, there is not only a soil path for the stray current but also an internal path through the aqueous medium where corrosion will occur as illustrated in

Figure 5.4

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Figure 5.4-Stray Current Discharge and Pick-Up Through the Internal Aqueous Medium Around an

Electrically Discontinuous Bell and Spigot Joint Through on Cast Iron Piping (from NACE CP Interference)

5.2 Corrosion Investigation

The field investigation included testing to determine if the fish barrier signal is having any deleterious effects on adjacent buried utilities. The investigation included utilities at the three local residences, the Enbridge petroleum pipeline, barrier 2A building foundation/slab, Romeo bridge foundations, and the railroad rails.

5.2.1 Barrier 2A Building Corrosion

The floor of the building housing Barrier 2A equipment was evaluated on July 13, 2010 to determine if it is subject to corrosion from the fish barrier current flow.

Inspection methods included a visual examination and potential measurement testing.

The visual examination did not yield any evidence of cracking or rust staining of the building floor. Rebar potential measurements were performed at approximate 10 foot intervals. Refer to potential test results in Appendix A. Results indicated that the rebar in the building floor is under the influence of the barrier current. Negative potentials extreme as -924 mV were observed indicating current pickup locations. Positive potentials extreme as +410 mV were measured in the southwest corner of the building.

These positive potentials are indicative of current discharge and active corrosion.

5.2.2 Romeo Bridge Footing Corrosion

Potential measurements were attempted on the Romeo Bridge footings to determine if the rebar is subject to current pickup and discharge from the fish barrier.

Attempts to make electrical connection to the footing rebar through the bridge beams and expansion joints were not successful. There was some cracking and rust staining observed on the exposed supports. This is probably the result of chloride ingress from

5-4 road de-icing salts and not associated with current discharge and associated corrosion.

5.2.3 Enbridge Pipeline

Pipe-to-soil potential measurements were performed on the Enbridge pipeline at the east and west sides of the pipe bridge and at a rectifier location on 135th Street across from CITGO. There was no evidence of the fish barrier signature at either the west side of the pipe bridge or at the 135th Street location. A very slight signature was observed at the east side of the pipe bridge. Potential measurements indicate that the piping is meeting the criteria for cathodic protection at all locations tested. The fish barrier is not having any adverse corrosion effects on the pipeline at the locations spot tested. Refer to

Appendix A for the Enbridge piping test data.

5.2.4 Residential Utilities

The owner of the local residences replaced three water well pumps at 800 E Old

Romeo Rd since February 2010 due to corrosion damage. The owner recounted the history of pump replacement. A Franklin pump was replaced in February 2010 after 16 years of service. The new pump was replaced on 18 Jun 2010 with a Flotec pump, which required replacement on 29 Jun 2010. The pump currently in service is a Franklin

Electric pump. An inspection of the replaced pumps indicated through-wall corrosion and corrosion of the pump screws.

The well construction consists of a 220 V AC submersible pump approximately

60 ft below the ground surface. The well casing from the ground surface down is 5” PVC casing followed by 4” diameter…