Fish_Barrier_Site_Reports_for_Contractor_Informational_Purposes.pdf

CSSC Fish Barrier Simulated

Rescuer Touch Point Results, Operating Guidance, and

Recommendations for Rescuer

Safety – Final Report

September 2011

Distribution Statement A.: Approved for public release, distribution is unlimited.

CSSC Fish Barrier Simulated Rescuer Touch Point Results, Operating Guidance, and Recommendations for Rescuer Safety – Final Report

UNCLAS//Public | CG-926 RDC | M. Slater et al. | Public ii

N O T I C E

This document is disseminated under the sponsorship of the Department of Homeland Security in the interest of information exchange. The United States Government assumes no liability for its contents or use thereof.

The United States Government does not endorse products or manufacturers.

Trade or manufacturers’ names appear herein solely because they are considered essential to the object of this report.

This report does not constitute a standard, specification, or regulation.

Gary L. Hover Aviation Branch Chief United States Coast Guard Research & Development Center 1 Chelsea Street New London, CT 06320 iii

Technical Report Documentation Page

1. Report No.

2. Government Accession Number

3. Recipient’s Catalog No.

4. Title and Subtitle

CSSC Fish Barrier Simulated Rescuer Touch Point Results, Operating Guidance, and Recommendations for Rescuer Safety – Final Report

5. Report Date

September 2011

6. Performing Organization Code

Project No. 1022

7. Author(s)

Michael Slater, Norbert Yankielun, John Parker, M. J. Lewandowski

8. Performing Organization Report No.

RDC UDI No. 1142

9. Performing Organization Name and Address

U.S. Coast Guard Research and Development Center 1 Chelsea Street New London, CT 06320

SAIC

23 Clara Drive, Suite 206 Mystic, CT 06355-1959

10. Work Unit No. (TRAIS)

11. Contract or Grant No.

Contract HSCG32-10-D-R00021/ Task Order HSCG32-10-J-300002

12. Sponsoring Organization Name and Address

U.S. Department of Homeland Security Commandant (CG-534), (CG-5213) United States Coast Guard 2100 Second St. SW Washington, DC 20593-0001

13. Type of Report & Period Covered

Final

14. Sponsoring Agency Code

Commandant (CG-534), (CG-5213) U.S. Coast Guard Headquarters Washington, DC 20593-0001

15. Supplementary Notes

The R&D Center's technical point of contact is Marion J. Lewandowski, 860-271-2692, email: M.J.Lewandowski@uscg.mil.

16. Abstract (MAXIMUM 200 WORDS)

Purpose: The Chicago Sanitary and Ship Canal (CSSC) has electric dispersal barriers in operation to prevent the spread of aquatic nuisance species. The experiment was to better understand what would actually occur during a rescue in the electrified waters with three barriers energized. An additional purpose was to identify any methods, devices, or operating guidance to prevent potential harm to a rescuer.

Methods: Voltage measurements under controlled conditions were taken during transits in the regulated navigation area using aluminum and fiberglass-hulled vessels to determine the current a rescuer would be exposed to. Monitoring of voltage levels and vessel position continuously took place throughout the transit. Devices evaluated for potential rescuer use included life rings/throw lines and non-conducting boat hooks. Measurements taken along the canal bank assisted in determining currents a rescuer from shore would experience.

Results: Under certain operating conditions and with non-conductive apparatus, rescuers may be able to safely assist person in the water to move them away from the barriers. The rescuer and victim must be isolated from a vessel metal hull for recovery, and use of a fiberglass-hulled vessel provides improved protection over an aluminum-hulled vessel. Some areas of the canal upstream of Barriers IIA and IIB may support a shore-side rescue.

17. Key Words

Electric fish barrier, electrified water, rescue, CSSC, Asian carp, Barrier IIA, Barrier IIB, demonstration barrier

18. Distribution Statement

Distribution Statement A. Approved for public release, distribution is unlimited.

19. Security Class (This Report)

UNCLAS//Public

20. Security Class (This Page)

UNCLAS//Public

21. No of Pages

22. Price mailto:M.J.Lewandowski@uscg.mil iv

This page intentionally left blank.

v

ACKNOWLEDGEMENTS

The Coast Guard Research & Development Center (RDC) would like to express deep gratitude to the U.S.

Army Corps of Engineers (USACE) Chicago District Engineer staff for their wholehearted support to the field-test team while working in the vicinity of the Chicago Sanitary and Ship Canal (CSSC) barrier. The RDC and Science Applications International Corporation (SAIC) greatly appreciate the technical assistance provided to help expedite data collection, especially the on-site effort to allow clear access to the West bank of the Canal, help with solving data recording power supply and equipment mobility issues, and the frequent changing of barrier operating parameters during data collection runs.

The RDC also recognizes the support of the local Coast Guard units, including Sector Lake Michigan, Marine Safety Unit Chicago, and Station Calumet Harbor, and the Illinois Department of Natural Resources for providing canal closure and patrol efforts that played a significant contribution to the field team safety during in-the-water data collection efforts.

vi vii

EXECUTIVE SUMMARY

The U.S. Army Corps of Engineers (USACE) constructed a demonstration electric fish barrier (Barrier I) across the Chicago Sanitary and Ship Canal (CSSC) at river mile 296.5 and first energized it in 2002.

USACE initially constructed the demonstration barrier to prevent dispersal of aquatic nuisance species, including the round goby and white perch, to and from the Great Lakes and Mississippi River Basins.

Additionally, the barrier is intended to counter an invasive species threat from the Asian carp, which is seen as a significant impact to native species in the Great Lakes. Various species of Asian carp were originally imported into the U.S. in the early 1970’s for use in Arkansas fish farms to improve water quality and increase fish production.

With the success of the demonstration barrier, USACE determined it necessary to construct a permanent barrier (Barrier II) in two phases, IIA and IIB. Barriers IIA and IIB reached final operational status in 2009 and June 2011, respectively. The combined electrical capabilities of Barriers IIA/B exceed Barrier I (demonstration barrier) electrical capability.

USACE conducted in-water testing in 2008 on barge operations in the canal barrier zone, with efforts made to evaluate the risk to vessels and humans from electrified waters. Under contract by USACE, the Navy Experimental Diving Unit (NEDU) published a study that found that voltage gradients measured in the CSSC could be life threatening, and could pose a significant risk to humans immersed in the canal near the fish barriers. USACE conducted additional in-water testing through 2011. As a result of these various tests and studies, specific precautions are required of all vessels and personnel transiting the barriers from river mile 296.1 through 296.7, from Romeo Road Bridge to the aerial pipeline arch. Testing to date has also (1) characterized the electrical voltage field in the canal, (2) determined its effects on surface vessels and barges, (3) evaluated electrical contacts among vessels comprising a long tow, and (4) evaluated the potential for sparking during barge fleeting operations or in the case of an allision.

Coast Guard Sector Lake Michigan (SLM) is the Coast Guard operational field commander with overall responsibility for marine safety and maritime search and rescue (SAR) in the area of the electrified barrier.

After the initial safety studies, SLM requested the Coast Guard Research & Development Center (RDC) to assist in developing a CSSC Fish Barrier SAR policy. RDC conducted a short-term project that reviewed and summarized the previous work. Recommendations of the project were to further investigate SAR mission capabilities and gaps for electrified water conditions and to identify or develop specialized SAR equipment (non-conductive poles, rescue loops or devices) for safe retrieval of persons in the water (PIWs).

The primary purpose of this study is to focus on the ability to provide safe rescuer response actions to assist a PIW. At certain levels, electrical current through the human body can have a range of effects: from a tingle sensation at the threshold of perception, to uncontrollable muscle contractions, to direct effects on the heart. This study focuses on assessing possible conditions that would be encountered during a rescue, specifically the amount of electrical current potentially experienced by the rescuer.

RDC and Science Applications International Corporation (SAIC) designed and conducted a series of tests at the CSSC on 17, 18, and 19 November, 2010. These tests followed a variety of specific data acquisition and test apparatus set-up conditions from a formal test plan to assess whether identified rescue techniques are safe and effective for use in a real rescue scenario within the electrified area. A series of follow-on tests viii were designed and conducted at the CSSC on 18, 19, 20, and 21 July, 2011 to better understand rescue methods, including testing with a fiberglass-hulled vessel. Testing in July 2011 included conditions with Barriers IIA and IIB operating at 2.3 volts/inch.

Experimental efforts focused on measuring electrical current flow through a simulated human rescuer under each touch-point condition outlined in the test plan. A series of detailed measurements along the west bank of the CSSC quantified the effects to a potential rescuer conducting a shore-side rescue, and to identify areas that might be suitable for shore-side rescue.

Data analysis showed that significant electrical currents could be encountered within the electrified area of the CSSC and, without significant precautions, could endanger rescue personnel. Voltage levels in the canal were of sufficient strength, and with a sufficient level of electrical current capacity, to impart potentially harmful electrical currents to rescuers. In general, non-conductive or resistive materials, such as rubber, plastic and fiberglass, are effective in reducing the electrical current risk to a rescuer, so long as rescuers understand the electrical current paths, and take actions to avoid or minimize them. A fiberglass-hulled vessel provides good protection for rescuers if precautions are taken to avoid touching metallic items on the vessel that are in contact with the water, such as the motor or motor brackets, and would include other items such as over-the-side ladders or railings.

Additionally, a rescuer on shore could encounter significant electrical currents within the electrified area of the CSSC and, without precautions, could put themselves or others in danger. However, there are limited locations along the West bank of the canal where a rescuer might not encounter an measurable electrical current by making contact with a PIW. As with rescue from a vessel, a potential rescuer must take many of the same precautions, including use of non-conductive equipment and isolation materials, and avoid contact with metallic objects such as fence posts, sign posts, or electrical boxes which were shown during testing to provide a low-resistance ground path for electrical current, thus creating a higher risk of shock hazard.

WARNING

Under no circumstances should a rescuer enter or immerse any part of their body directly into the electrified waters in the CSSC. A rescuer should not make contact with any PIW (in the electrified area) unless the rescuer is electrically isolated from the PIW. Any attempt at rescue in electrified water conditions is inherently hazardous.

This report offers recommendations to mitigate hazards to rescuers, but not eliminate them. Nothing in this report should be construed that rescue in electrified water is anything but a hazardous undertaking.

ix

TABLE OF CONTENTS

ACKNOWLEDGEMENTS .......................................................................................................................... v

EXECUTIVE SUMMARY ......................................................................................................................... vii

LIST OF FIGURES ...................................................................................................................................... xi

LIST OF TABLES ....................................................................................................................................... xii

LIST OF ACRONYMS AND SYMBOLS ................................................................................................ xiii

1 INTRODUCTION

2 METHODOLOGY

2.1 Mobilization and Test Set-up

2.2 Data Acquisition Set-up

2.2.1 Sensors

2.2.2 Rescue Test Apparatus

2.2.3 Electrical Sensing and Recording

2.2.4 Position Instrumentation

2.3 Ancillary Data

2.3.1 USACE Barrier Data Logs

2.3.2 Water Conductivity Measurements

3 DATA COLLECTION AND ANALYSIS

3.1 Data Collection Overview

3.2 Observations

3.2.1 Test Condition 1: Free-field Current

3.2.2 Test Condition 2: Rescue Vessel Recovery Touch-point Current

3.2.3 Test Condition 3: Shore Recovery Touch-point Current

3.2.4 Test Condition 6: Rescue Apparatus

4 ELECTRIC CURRENTS AND THE HUMAN BODY

4.1.1 An Illustration

4.1.2 Cardiac Physiology

5 DISCUSSION OF RESULTS

6 CONCLUSIONS

7 RECOMMENDATIONS

8 REFERENCES

APPENDIX A MEASUREMENT TEST BOX SCHEMATIC .......................................................... A-1

APPENDIX B BARRIER ELECTRICAL OPERATING PARAMETERS ..................................... B-1

APPENDIX C SHORE TOUCH POINT DATA LOG ....................................................................... C-1 x xi

LIST OF FIGURES

Figure 1. L&R aluminum test vessels Figure 2. Towed free-field sensor array apparatus loaded on test vessel

Figure 3. General arrangement of Safety Zone and major landmarks Figure 4. Lindahl Marine Contractors fiberglass test vessel Figure 5. Shore touch-point data acquisition equipment set-up Figure 6. Free-field towed array apparatus during tow Figure 7. Configuration of electrode sensor array with color-coded electrode pairs

Figure 8. Shore touch-point wet-end electrode Figure 9. Shore touch-point ground electrode

Figure 10. Polypropylene rope test

Figure 11. Non-conductive rescue hook test Figure 12. Electric field recording system block diagram Figure 13. Electrical sensing test box physical set-up Figure 14. GPS receivers and loggers on deck of test vessel

Figure 15. Peak free-field electrical current (mA) between horizontal electrodes, 72” apart, oriented parallel to vessel track, 2.3 volts/inch

Figure 16. Peak free-field electrical current (mA) between horizontal electrodes, 72” apart, oriented parallel to vessel track, 2.0 volts/inch

Figure 17. Peak rescue vessel electrical current (mA), aluminum hull, 2.3 volts/inch

Figure 18. Peak rescue vessel electrical current (mA), aluminum hull, 2.0 volts/inch Figure 19. Peak rescue vessel electrical current (mA), fiberglass hull, 2.3 volts/inch

Figure 20. Peak rescue vessel electrical current (mA), fiberglass hull, 2.0 volts/inch

Figure 21. Peak rescue vessel electrical current (mA), fiberglass hull, metal motor mount,

2.0 volts/inch

Figure 22. Results for shore touch-point current, “earth ground”, all barriers operating Figure 23. Results for shore touch-point current, “metallic ground”, all barriers operating

Figure 24. Results for shore touch-point current, “earth ground”, Barrier IIA “off” Figure 25. Results for shore touch-point current, “metallic ground”, Barrier IIA “off”

Figure A-1. Measurement test box schematic diagram. ............................................................................. A-1 xii

LIST OF TABLES

Table 1. Daily mobilization schedule Table 2. GPS data recording format

Table 3. Canal conductivity Table 4. Test condition log Table 5. Test Condition 1, free field test results Table 6. Test Condition 2, vessel touch-point results Table 7. Test Condition 6, rescue apparatus results

Table B-1. Barrier IIA nominal electrical parameters (18-21 July 2011). .................................................. B-1 Table B-2. Barrier IIB nominal electrical parameters (18-21 July 2011). .................................................. B-1

Table C-1. Test Condition 3 highest peak currents, all barriers operating. ................................................ C-1

Table C-2. Test Condition 3 highest peak currents, demonstration barrier and Barrier IIB only. ............. C-2 xiii

LIST OF ACRONYMS AND SYMBOLS

µS/cm MicroSiemens per centimeter A/D Analog-to-digital AC Alternating current amp Ampere ATV all-terrain vehicle AWG American Wire Gauge COTP Captain of the Port CSSC Chicago Sanitary and Ship Canal DC Direct current EKG Electrocardiogram GMT Greenwich mean time GPS Global Positioning System HDOP Horizontal dilution of position Hz Hertz ID Identification IL Illinois kHz Kilohertz kW KiloWatt L&R Lakes & Rivers Contracting, Inc.

mA Milliampere mph Mile per hour ms Millisecond NEDU Navy Experimental Diving Unit PIW Person in the water RDC Research & Development Center RF Radio frequency rms Root mean square SAIC Science Applications International Corporation SAR Search and rescue SLM Sector Lake Michigan TSS Three-conductor, shielded, shipboard U.S. United States UPS Uninterruptible power supply USACE United States Army Corps of Engineers USB Universal serial bus USCG United States Coast Guard V/in Volts/inch VAC Volts alternating current VDC Volts direct current xiv

1 INTRODUCTION

The United States Army Corps of Engineers (USACE) operates a series of electric barriers in the Chicago Sanitary and Ship Canal (CSSC) in an effort to reduce the risk of inter-basin transfer of fish between the Great Lakes and Mississippi River Basins via the CSSC. USACE installed Barrier I (Demonstration) in 2002; it operates at a nominal level of 1 volt/inch, with a 5 Hertz (Hz) repetition rate and 4 milliseconds

(ms) pulse duration. It was initially constructed to prevent dispersal of aquatic nuisance species, including the round goby and white perch, to and from the Great Lakes and Mississippi River Basins (Reference 1).

The barrier is also intended to counter an invasive species threat from the Asian carp, which is seen as a significant threat to native species in the Great Lakes. Various species of Asian carp (Reference 2) were originally imported into the United States (U.S.) in the early 1970’s for use in Arkansas fish farms to improve water quality and increase fish production (Reference 2).

USACE conducted testing in 2008 on barge operations in the canal barrier zone with efforts made to evaluate the risk to vessels and humans from electrified waters (Reference 3). Under contract by USACE, the Navy Experimental Diving Unit (NEDU) published a study that found that voltage gradients measured in the CSSC could be life threatening, and could pose a significant risk to humans immersed in the canal near the fish barriers (Reference 4). USACE conducted additional in-water testing through 2011 (Reference 5). As a result of these various tests and studies, specific precautions are required of all vessels and personnel transiting the barriers from river mile 296.1 through 296.7, from Romeo Road Bridge to the aerial pipeline arch. Testing to date has also (1) characterized the electrical voltage field in the canal barrier zone, (2) determined its effects on surface vessels and barges, (3) evaluated electrical contacts among vessels comprising a long tow and (4) evaluated the potential for sparking during barge fleeting operations or in the case of an allision. Reference 5 provides comprehensive results from these tests.

Coast Guard Sector Lake Michigan (SLM) is the Coast Guard operational field commander with overall responsibility for marine safety and maritime search and rescue (SAR) in the area of the electrified barrier.

After the initial safety studies (Reference 6), SLM requested the RDC to assist in developing a CSSC Fish Barrier SAR policy. RDC conducted a short-term project that reviewed and summarized the previous work.

Recommendations of the project were to further investigate SAR mission capabilities and gaps for electrified water conditions and to identify or develop specialized SAR equipment (non-conduction poles, rescue loops or devices) for safe retrieval of persons in the water (PIWs) (References 7 and 8).

With the success of the demonstration barrier, USACE determined it necessary to construct a permanent barrier (Barrier II) in two phases, IIA and IIB. Barrier IIA, a permanent barrier which is larger and more powerful than the demonstration barrier, has been operational since 2009, initially with the same operational parameters as the demonstration barrier; then in August 2009, USACE increased the strength of the electric field produced by Barrier IIA to 2.0 volts/inch, with a 15 Hz repetition rate and 6.5 ms pulse duration.

USACE has completed construction on a third barrier, Barrier IIB, which was energized during the July 2011 data collection period. Barriers IIA and IIB were operated at 2.0 and 2.3 volts/inch during specific tests identified to evaluate and compare results between the two operational conditions. This study is not intended to characterize the electric field itself, but to focus on the effects of the field on potential rescuers and rescue scenarios. Section 4 provides a brief tutorial on the effect of electric currents on the human body.

2 METHODOLOGY

We conducted all testing in accordance with an experiment test plan (Reference 7) that laid out the test conditions, resources, and experimental apparatus for each scenario. We conducted testing from vessels in the canal and from shore along the west bank. Prior to testing each day, the Test Director provided a briefing to all embarked personnel, and reviewed communications and safety procedures. We tested barriers at 2.0 volts/inch and 2.3 volts/inch. Due to safety considerations for other traffic on the CSSC at the higher voltage conditions, the canal was shut down to traffic during specific time periods each test day. We conducted all test vessel operations in accordance with a regulatory waiver from the United States Coast Guard (USCG) Captain of the Port (COTP) Lake Michigan. Coast Guard Sector Lake Michigan (SLM) and Illinois Department of Natural Resources stationed vessels at either end of the Safety Zone during all test days for canal closure enforcement and immediate response, if required.

2.1 Mobilization and Test Set-up

We mobilized for each test day depending on the specific needs to achieve test conditions in the plan. On 18 and 19 July we mobilized aluminum vessels from the Lakes & Rivers Contracting, Inc. (L&R) facility, Lemont, Illinois (IL). We used an enclosed aluminum-hulled vessel for free-field testing on 18 July (see Figure 1, left photo), which was the same test vessel used during November 2010 testing (Reference 8). A mechanical issue with this vessel prevented continuation of this testing on the following day, so an open cockpit aluminum-hulled vessel was used for testing on 19 July (see Figure 1, right photo).

Figure 1. L&R aluminum test vessels.

We configured a towed sensor array apparatus (to be described in section 2.2) using a commercial pontoon boat, with outriggers and keel features to attach electrodes. We loaded the apparatus onto the test vessel, and secured it to the deck (Figure 2). We stowed the data recording electronics inside the cabin, and powered the system using 120 volts alternating current (VAC) conditioned power from a commercial uninterruptible power supply (UPS) fed by the output of a small gasoline-powered portable generator. With the open cockpit vessels, we mounted a temporary awning to protect the data recording equipment and crew from the sun.

Figure 2. Towed free-field sensor array apparatus loaded on test vessel.

We transited to an electrically safe area north of the aerial pipeline arch and deployed the towed array apparatus into the water and attached it to the aft railing of the test vessel with a polypropylene tow rope.

Next, we confirmed the operation of the sensor array and data acquisition system and proceeded to perform the scheduled survey with the vessel maintaining a speed (measured by a Global Positioning System (GPS)) in the range of approximately 0.5 to 3.0 miles per hour (mph). This speed permitted high spatial density data acquisition. We arranged the transects to acquire data along tracks near the eastern and western banks and in the mid-channel of the canal within the barrier zone. The canal was closed to traffic during testing, enabling uninterrupted data collection. We exited the barrier area to make configuration changes to the sensor and test conditions in accordance with the experiment test plan (Reference 7). Figure 3 shows the general arrangement of the barrier Safety Zone with major landmarks.

We tested using a fiberglass-hulled vessel provided by Lindahl Marine Contractors on 20 July (see Figure 4), and loaded test equipment pier-side at Hanson Materials Services in Romeoville.

Figure 3. General arrangement of Safety Zone and major landmarks.

Figure 4. Lindahl Marine Contractors fiberglass test vessel.

The team conducted shore touch-point measurements from the west canal bank on 21 July, and did not use a test vessel for support. Instead, we loaded the data acquisition equipment into an all-terrain vehicle (ATV), and connected to a gasoline-powered generator in a small trailer (see Figure 5). We maneuvered the ATV along the roadway along the canal, but outside the security fence. We routed an insulated sensor cable from the ATV to the bank of the canal where we connected it to the wet end and grounding electrodes.

Figure 5. Shore touch-point data acquisition equipment set-up.

Table 1 summarizes the daily mobilization schedule for the July 2011 test series.

Table 1. Daily mobilization schedule.

Test Date Test Vessel, Location, and Condition 18 July, 2011 L&R enclosed aluminum hull, free-field with towed apparatus;

Mobilized from L&R Contracting at Lemont, IL 19 July, 2011 L&R open aluminum hull, rescue apparatus;

Mobilized from L&R Contracting at Lemont, IL 20 July, 2011 Lindahl Marine, enclosed fiberglass hull, rescue apparatus;

Mobilized from Hanson Materials Services near Romeoville, IL 21 July, 2011 No vessel used, shore touch-point current, west bank;

Mobilized at CSSC, west bank location

2.2 Data Acquisition Set-up

We used a similar instrumentation set-up as was used during the November 2010 data collection period (Reference 8). The apparatus and data acquisition set-up also incorporated recommendations and lessons learned from USACE experience in electric field data collection in the CSSC. The electronics signal conditioning, sensing, and recording equipment was the same for both test periods. The primary difference with the new set-up was the in-water sensing configuring, including the use of a commercial pontoon boat as the towed sensor array for free-field testing (see Figure 6). The new fixture allowed free-field measurements of a simulated PIW away from the tow vessel, and furthermore provided simultaneous sensing of horizontal field strength conditions in two orthogonal directions (along the canal, parallel the test vessel track, and side-to-side in the canal, perpendicular to the test vessel track.)

Figure 6. Free-field towed array apparatus during tow.

2.2.1 Sensors

2.2.1.1 Input Electrodes, In-water Testing

Input electrodes consisting of 1/2” diameter, 6” long copper rods were wired to separate conductors of a shielded, commercially available, underwater-rated electrical cable (three-conductor, shielded, shipboard cable (TSS-2), 18 American Wire Gauge (AWG) stranded copper). Electrode pairs shared a single signal cable to minimize interference from external sources during testing. We polished the surface of electrodes with fine grit sandpaper prior to use to ensure the best electrical continuity between the water and electrode by removing any copper oxide. This electrode configuration differed from the previous (July 2010) configuration, in which copper rod electrodes were encapsulated in a conductive diatomaceous mixture to provide an approximate bulk resistivity of a PIW. We observed during the November 2010 testing that we could more closely control the simulated resistivity of a PIW using series resistors in the signal path.

We mounted six electrodes to a wooden framework mounted to the towed pontoon boat frame to create three pairs of electrodes (Figure 7). We arranged one pair of electrodes to provide 72” spacing fore-and-aft, nominally 12” below the water surface, a second pair to provide 72” spacing side-to-side, also 12” below the water surface, and the third pair 48” vertically, with the upper electrode 12” beneath the surface, and the other 60” below the surface. We used this configuration to assess the electrical exposure to a PIW swimming along the canal, across the canal, or in a vertical position. (Due to hydrodynamic limitations of the towed platform, we were not able to attain the originally desired 72” vertical spacing.) We twisted pairs of 1000 V rated electrode wires, secured them to the tow rope, and terminated them to the TSS-2 cable located on the back desk of the test vessel. We labeled each wire pair with colored electrical tape (green, yellow, and red) to provide ease of identification for each pair of electrodes: green for 72” side-to-side orientation, yellow for 72” fore-aft orientation, and red for 48” foot vertical separation.

72" fore-and-aft

Direction of Travel

48" vertical

72" side-to-side

Figure 7. Configuration of electrode sensor array with color-coded electrode pairs.

2.2.1.2 Input Electrodes, Shore Touch-point Testing

For the wet-end electrode, we arranged a bare copper electrode for our positive lead (see Figure 8, left photo) similar to those used for in-water testing, with floats (see Figure 8, right photo) rigged to maintain an electrode depth in water of approximately 12”. Our ground electrode was comprised of an aluminum plate and flexible copper grounding strap (see Figure 9, left photo). For testing, we moistened the vegetation and soil immediately beneath the plate at each test location with fresh water, and weighted the plate with a

2.5 gallon water jug (Figure 9, right photo). Both electrodes were cabled to the TSS-2 cable using 1000 V rated insulated wire. We fastened the wet electrode to a monofilament fishing line and lowered it into the water at each test location with a fiberglass fishing rod.

Figure 8. Shore touch-point wet-end electrode.

Figure 9. Shore touch-point ground electrode.

2.2.2 Rescue Test Apparatus

We tested two types of rescue apparatus from the aluminum and fiberglass-hulled test vessels:

(1) polypropylene rope to simulate towing a PIW; and (2) a non-conductive rescue hook to simulate grasping or towing a PIW. A commercially available life-ring rope bag (Stearns part number #I023ORG- 00-000) with a 3/8” open-braid polypropylene line served as the test line for the poly rope test. The wet-end of the poly rope was wrapped around a copper electrode, and submerged beneath the life ring for towing.

The dry end of the rope was wrapped around a metal wrench, and terminated into the electrical sensing instrumentation. The ground lead was connected to the test vessel hull. The test vessel towed the simulated PIW and life-ring assembly approximately one boat length (Figure 10) behind it. A length of the polypropylene line approximately 25’ long was predominately out of water during the tow. We submerged the rope prior to the test to ensure it was as wet as possible during the electrical current testing.

Figure 10. Polypropylene rope test.

We fitted the non-conductive rescue hook to a copper electrode on the wet end (hook end) to simulate the PIW, and lashed it to the life ring to provide flotation during towing. The dry end was wrapped in foil to provide some continuity with the pole, and the electrically isolated from the test vessel with switchgear mat and a wooden strut (see Figure 11).

Figure 11. Non-conductive rescue hook test.

2.2.3 Electrical Sensing and Recording

The data acquisition collection system included a Dell D520 laptop computer, a 4-channel analog-to-digital (A/D) converter, high-voltage differential probes, measurement resistors, and input electrodes. Figure 12 depicts a top-level block diagram of the data acquisition system. We wired the input electrodes to the data acquisition system inputs via submersible electrical cables. We used the electronics, which were housed in a weather-proof case, to sample, digitize, and store collected data onto the laptop hard drive for real-time monitoring, playback, and analysis.

Isolation Switches

Calibration Resistors

Input Electrodes

Analog-to-Digital Converter

High-Voltage Differential Probes

Laptop Computer with Real-Time Display

Isolation Switches

Calibration Resistors

Input Electrodes

Analog-to-Digital Converter

High-Voltage Differential Probes

Laptop Computer with Real-Time Display

Figure 12. Electric field recording system block diagram.

We wired three-pole, double-throw switches to the input side of the test box to enable the user to completely disconnect and isolate the test box from electrodes in the water if required for testing or system reconfiguration. We used these switches between test condition set-ups, and they were necessary during troubleshooting of the system while deployed. We used Tektronix P5200 High-Voltage Differential Probes for each channel of measurement for voltage stepdown and circuit protection and personnel safety. Each P5200 contains optical isolation circuitry that prevents excessive voltages on the signal side of the unit that could damage the low voltage circuits on the recorder. This protection was necessary due to the high voltages produced by the barriers. The P5200s were powered by a 9 volts direct current (VDC) supply and were configured for a 1:500 stepdown rate.

We measured voltage levels across commercial high-power resistors of a nominal 500 ohm resistance. The high power rating (200 watts) allowed safe use and substantial power dissipation when exposed to high voltages from the barrier. We wired the measurement resistors in series with the input electrodes. Figure 13 shows the measurement test box; Appendix A provides an electrical schematic.

Measurement

Resistors

Isolation

Switches

High Voltage

Differential

Probes

4-Channel

USB A/D

Measurement

Resistors

Isolation

Switches

High Voltage

Differential

Probes

4-Channel

USB A/D

Figure 13. Electrical sensing test box physical set-up.

We wired the signals for each sensor to individual channels of a differential input, 4-channel National Instruments USB-9215A universal serial bus (USB)-powered A/D unit, which digitized the data at a 10 kilohertz (kHz) sampling rate and transmitted the digital data to the laptop computer. We equipped the laptop computer with customized automated signal processing LabVIEW™ software that received the data and formatted it for storage in a binary file format on the laptop hard drive. Data were continuously sampled and stored at 5-minute periods for all test conditions. We programmed the recording system to autonomously record data for a continuous 5-minute period throughout the testing period. We saved data files in a time-tagged format to allow reconstruction with the vessel positional information.

2.2.4 Position Instrumentation

Portable GPS receivers with built-in data logging capabilities provided positional information during periods of data collection. Two units periodically recorded test vessel position as a function of time, one unit as the primary, and the other as a backup. We staged GPS units on the deck of the test vessel (see Figure 14).

Figure 14. GPS receivers and loggers on deck of test vessel.

During the survey, two onboard GPSs continually and simultaneously recorded the test vessel position at a rate of approximately 10 to 12 times a minute. Data recorded by the GPS included: latitude (DD.DDDDDD format), longitude (DD.DDDDDD format), date (ddmmyy), time (hhmmss) relative to Greenwich mean time (GMT), vessel speed (mph), and vessel track (degrees magnetic), and other data.

Table 2 shows the basic recording format with a segment of run data from the 18 July testing. GPS positions were recorded using WGS84 datum. We computed positional graphs of test vessel transects each run day for each test condition and time-synchronized them to the recorded electric field data.

Table 2. GPS data recording format.

Fix Latitude (N)

Longitude

(W) Time Date Speed Vessel

Track Altitude HDOP* Satellites

D 41.64565 88.05968 154222 180711 2.1 006 587 1.2 10 D 41.64568 88.05967 154226 180711 2.2 007 587 1.2 10 D 41.64572 88.05967 154230 180711 2.2 008 587 1.3 9 D 41.64577 88.05965 154236 180711 2.2 005 587 1.4 10 D 41.64582 88.05965 154240 180711 2.2 003 587 1.1 10

*horizontal dilution of position

The GPS latitude and longitude data acquired during each survey were synchronized in time with the recorded electrical data files, and plotted in ArcView over satellite imagery.

2.3 Ancillary Data

In addition to electronically recorded data, barrier operational conditions and water conductivity data were also acquired.

2.3.1 USACE Barrier Data Logs

USACE personnel at each barrier logged operational conditions of each barrier, including the voltage, current, and power levels, as well as pulse length and pulser frequency. Conductivity measurements of the canal water and nominal in-water voltages were also logged. Appendix B provides summary values of the barrier operating conditions during the test days for Barriers IIA and IIB.

2.3.2 Water Conductivity Measurements

We used a commercial hand-held conductivity meter and probe to measure the electrical conductivity of the water in the canal each test day. Table 3 shows measured values which were taken over the side of the test vessel outside the electrified zone near the pipeline arch, at the water surface. Water conductivity differed slightly each day, and values agreed within a few percentage points. Measured values were similar to those logged by USACE personnel taken at the same time. Values were logged periodically throughout each test day by USACE personnel, and values did not vary more than approximately 8% over the course of the week.

Table 3. Canal conductivity.

Date (2011) Time

Measured Conductivity

(µS/cm*)

Conductivity from Barrier IIA Logs1

(µS/cm) 18 July 11:45 AM 749 818 19 July 08:43 AM 747 843 20 July 09:05 AM 815 818 21 July 11:00 AM N/A2 827

*microSiemens per centimeter 1Logged at approximately the same time as the measured values.

2Measurement of the canal conductivity from the west canal bank was not possible due to safety constraints in gaining access to the canal from the bank.

3 DATA COLLECTION AND ANALYSIS

3.1 Data Collection Overview

We performed all testing in accordance with the experiment test plan (Reference 7). Table 4 provides a summary of the test conditions conducted, and start/stop times for each condition.

Table 4. Test condition log.

Test Condition Test Condition Description

Barrier

IIA

(V/in*)

Barrier

IIB

(V/in) Start Date/Time Finish Date/Time

1 Free-field current, towed sensor array 2.3 2.3 2.3

2.0 2.3 2.3

7/18/2011 10:32 AM

7/18/2011 10:49 AM

7/18/2011 13:13 PM

7/18/2011 10:49 AM

7/18/2011 11:24 AM

7/18/2011 13:53 PM

1 Free-field current, towed sensor array 2.0 2.0 7/18/2011 13:55 PM 7/18/2011 14:51 PM 2 Rescue vessel recovery touch-point current, aluminum hull

2.3 2.3 7/19/2011 09:05 AM 7/19/2011 10:25 AM

2 Rescue vessel recovery touch-point current, aluminum hull

2.0 2.0 7/19/2011 10:30 AM 7/19/2011 12:05 AM

6A Polypropylene line, aluminum hull 2.3 2.3 7/19/2011 13:18 PM 7/19/2011 13:55 PM 6C Non-conductive rescue hook, aluminum hull

2.3 2.3 7/19/2011 14:23 PM 7/19/2011 14:49 PM

6C Non-conductive rescue hook, aluminum hull

2.0 2.0 7/19/2011 14:50 PM 7/19/2011 15:20 PM

2 Rescue vessel recovery touch-point current, fiberglass hull

2.3 2.3 7/20/2011 09:09 AM 7/20/2011 9:40 AM

6C Non-conductive rescue hook, fiberglass hull

2.3 2.3 7/20/2011 10:27 AM 7/20/2011 10:50 AM

6A Polypropylene line, fiberglass hull 2.3 2.3 7/20/2011 13:05 PM 7/20/2011 13:28 PM 6A Polypropylene line, fiberglass hull 2.0 2.0 7/20/2011 13:35 PM 7/20/2011 13:51 PM 6C Non-conductive rescue hook, aluminum hull

2.0 2.0 7/20/2011 14:02 PM 7/20/2011 14:16 PM

2 Rescue vessel recovery touch-point current, fiberglass hull

2.0 2.0 7/20/2011 14:22 PM 7/20/2011 14:38 PM

2 Rescue vessel recovery touch-point current, fiberglass hull, motor mount

2.0 2.0 7/20/2011 14:38 PM 7/20/2011 14:56 PM

3 Shore recovery touch-point current 2.3 2.3 0.0

2.3 2.3 2.3

7/21/2011 07:57 AM

7/21/2011 13:10 PM

7/21/2011 13:48 PM

7/21/2011 10:56 AM

7/21/2011 13:38 PM

7/21/2011 15:53 PM

*volts/inch

We conducted time-series analysis for each test condition, correlating specific maximum current (or voltage) events to a given test condition. For each test condition, we analyzed data recordings in back-to-back 5-second long periods, synchronizing results with the GPS positional data using Microsoft® Office Excel® and MATLAB® functions. For each 5-second period, we determined the peak voltage across each calibration resistor by locating the absolute value of the single sample with the highest magnitude within that period. In general, this single peak occurred at the “top” of the pulsed waveform, and occurred with both positive and negative polarity, depending on the location of the test vessel with respect to the pulser electrodes. In addition, we computed the root mean square (rms) amplitude of each 5-second period to establish the average current measured through each resistor during the period. We computed electrical currents using Ohm’s Law by dividing the measured voltage across each calibration resistor and dividing by the known resistance (500 ohms).

The measurement environment was very noisy from an electrical perspective. Several times during the experiment period, we intermittently observed external sources of electrical or radio frequency (RF) energy in the recorded data. Because the pulsed energy from the barriers provided a highly recognizable waveform, we edited suspected interference patterns from the data and did not process them for peak or rms data results. For various test conditions identified in Table 4, this report provides tabularized values and graphical charts that show the data results, and indicate the measured electrical current to human threshold sensitivity with a colorized scale.

Published human sensitivity data for electrical current were not available for the frequencies produced by the barrier pulsers (5, 15, and 30 Hz). Therefore, we analyzed human sensitivity to 60 Hz alternating current (AC) current following the human responses as described in the NEDU report (Reference 4) to approximate the expected response. In all cases, the peak currents are shown, which provides a more conservative (i.e., “worst-case”) estimate compared to the average or rms current for the same test condition.

3.2 Observations

3.2.1 Test Condition 1: Free-field Current

The objective of this test was to measure the expected worst-case electrical current flowing through the chest area of a PIW exposed to electric fields immersed in the CSSC. A towed sensor array was used such that it could be towed well behind the tow vessel to ensure that a true free-field condition was sensed;

previous tests used an apparatus mounted to the side of a test vessel, which could have affected the sensed readings. The towed sensor array provided measurement points along two orthogonal, horizontal directions (along the canal, parallel the test vessel track, and side-to-side in the canal, perpendicular to the test vessel track.), and one vertical direction. As expected, measured levels parallel to the canal varied substantially as the test vessel transited across each barrier. However, measured data in the orientation parallel to the canal flow direction did not vary significantly across the canal (center of the canal to the canal bank).

We observed significant electrical currents in this test condition, with barriers operating at both 2.0 and

2.3 volts/inch. Maximum currents measured occurred horizontally along the direction parallel to the canal axis, with peak levels of 330 milliampere (mA) observed for Barrier IIB operating at 2.3 volts/inch (see Table 5). Using 72” spacing, this current was equivalent to the nominal barrier setting of 2.3 volts/inch.

Figure 15 shows the peak free-field electrical current between horizontal electrodes, 72” apart, oriented parallel to vessel track. Maximum levels from Barrier IIA in this same operating condition (2.3 volts/inch) resulted in a worst-case peak current of 310 mA, equivalent to approximately 2.2 volts/inch. Measured levels for Barrier IIB were consistently higher than the same condition for Barrier IIA, although worst-case levels generally agreed to within approximately 8 percent. Results are scaled proportionally with barrier operational voltage in this orientation.

Table 5. Test Condition 1, free field test results.

Test Point/

Channel

ID*

Test Point Description

Worst-Case Peak Current (mA)

Barrier IIA Barrier IIB

A0 Channel 1, free-field current, 72” spacing, side-to-side orientation, perpendicular to canal flow, 2.3 volts/inch

48 54

A0 Channel 1, free-field current, 72” spacing, side-to-side orientation, perpendicular to canal flow, 2.0 volts/inch

47 50

A1 Channel 2, free-field current, 72” spacing, fore-aft orientation, parallel to canal flow, 2.3 volts/inch

310 330

A1 Channel 2, free-field current, 72” spacing, fore-aft orientation, parallel to canal flow, 2.0 volts/inch

275 290

A2 Channel 3, free-field current, 48” spacing, vertical orientation, 2.3 volts/inch

36 38

A2 Channel 3, free-field current, 48” spacing, vertical orientation, 2.0 volts/inch

26 30

A3 Channel 4, terminated into 500 ohms, reference noise, cable on deck

0.41

*identification 1rms current noise, not peak value. Channel used to assess system noise floor.

Worst-case current in the side-to-side direction (72” spacing, oriented perpendicular to canal) was about one-sixth the strength of along-track measurements (see Table 5) at both 2.3 and 2.0 volts/inch operating conditions. Measured worst-case current at the 48” vertical sensor spacing was 38 mA on Barrier IIB at the

2.3 volts/inch operating condition. At 2.0 volts/inch (Figure 16), the 48” vertical level was 30 mA, which did not scale as predictably as the along-canal direction. Rms noise measured during this test using a dry-cable terminated into a 500 ohm resistor was 0.4 mA; thus measured values consistently exhibited good signal-to-noise ratios.

Figure 15. Peak free-field electrical current (mA) between horizontal electrodes, 72” apart, oriented parallel to vessel track, 2.3 volts/inch.

Figure 16. Peak free-field electrical current (mA) between horizontal electrodes, 72” apart, oriented parallel to vessel track, 2.0 volts/inch.

3.2.2 Test Condition 2: Rescue Vessel Recovery Touch-point Current The objective of this test series was to measure the electrical current flowing through the touch-point of a rescuer on aluminum and fiberglass vessels, in contact with a floating PIW victim, with an electrical current path through the rescuer’s body, returning to the canal water through the hull of the test vessel.

3.2.2.1 Aluminum Hull Test Vessel

As in Test Condition 1, we observed significant electrical currents in this test condition. The maximum current measured in this condition was 191 mA (see Table 6). Figure 17 shows the peak current flowing from a PIW in direct contact with the metallic hull of a rescue vessel with Barriers IIA and IIB operating at

2.3 volts/inch. This test condition demonstrated that significant electrical currents can flow via a “victim” in the water through a “rescuer” electrically connected with a well-grounded metallic object (a vessel).

Furthermore, this test showed that the PIW should not directly touch the hand of a rescuer on an aluminum vessel, or the vessel hull. For this test, we executed several transects through the center of the canal and along both sides. Figure 18 shows results with an aluminum hull when operating the barriers at 2.0 volts/inch.

Table 6. Test Condition 2, vessel touch-point results.

Test Point/ Channel ID Test Point Description

Worst-Case Peak Current (mA)

Barrier IIA Barrier IIB A0 Channel 1, vessel touch-point current, aluminum hull, nominal 12” electrode depth, 2.3 volts/inch 160 175

A0 Channel 1, vessel touch-point current, aluminum hull, nominal 12” electrode depth, 2.0 volts/inch

131 158

A0 Channel 1, vessel touch-point current, aluminum hull, nominal 39” electrode depth, 2.0 volts/inch

191 138

A0 Channel 1, vessel touch-point current, fiberglass hull, 12” electrode depth, 2.3 volts/inch

<2 <2

A0 Channel 1, vessel touch-point current, fiberglass hull, 12” electrode depth, 2.0 volts/inch

<2 <2

A0 Channel 1, vessel touch-point current, fiberglass hull to metal motor mount, 12” electrode depth, 2.0 volts/inch

131 159

A3 Channel 4, terminated into 500 ohms, reference noise, cable on deck

<2 mA peak <.4 mA rms

Worst-case peak currents measured with the aluminum test vessel in July 2011 were 191 mA, with typical peak levels ranging from 131 mA to 175 mA for various barrier settings and electrode configurations (see Table 6). Measured current values from November 2010 were substantially higher (nearly 1 ampere (amp)) than measured in July 2011, most likely due to the test vessel configuration. In November 2010, an aluminum-hulled test vessel with a painted hull was used for the test, and the actual electrical current path was not surveyed which was well beyond the scope of the test. Therefore, the separation distance from the test electrode and the hull was not known, but could have been several times further apart than with the new, unpainted hulled vessel. Regardless, in both cases with the aluminum-hulled test vessel, the measured electrical currents were well above the onset level for fibrillation.

Figure 17. Peak rescue vessel electrical current (mA), aluminum hull, 2.3 volts/inch.

Figure 18. Peak rescue vessel electrical…